ALBERT

Description: 〈h3〉Abstract〈/h3〉 〈p〉A fluorimetric and colorimetric method is described for the determination of glutathione (GSH) and silver (I). It is based on the use of MnO〈sub〉2〈/sub〉 nanosheets that were prepared by solution mixing and exfoliation. They display oxidase-mimicking activity and can catalyze the oxidation of o-phenylenediamine (OPD) to form yellow 2,3-diaminophenazine (DAP) with an absorption maximum at 410 nm. DAP also has a yellow fluorescence (with a peak at 560 nm). The MnO〈sub〉2〈/sub〉 nanosheets can be rapidly reduced to Mn〈sup〉2+〈/sup〉 by GSH. This reduces the efficiency of the oxidase mimic MnO〈sub〉2〈/sub〉 and causes a decrease in fluorescence and absorbance intensity. However, on addition of Ag〈sup〉+〈/sup〉, a complex is formed with GSH. It prevents the destruction of MnO〈sub〉2〈/sub〉 nanosheets so that the enzyme mimicking activity is retained. A dual-method for the determination of GSH and Ag(I) was developed. It has excellent sensitivity for GSH with lower detection limits of 62 nM (fluorimetric) and 0.94 μM (colorimetric). The respective data for Ag(I) are 70 nM and 1.15 μM. The assay was successfully applied to the determination of GSH and Ag(I) in spiked serum samples.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of a method for colorimetric and fluorometric determination of glutathione (GSH) and silver(I). MnO〈sub〉2〈/sub〉 nanosheets are reduced to Mn(II) by GSH. This reduces the enzyme-mimicking activity of MnO〈sub〉2〈/sub〉 nanosheets and causes a decrease in fluorescence and absorbance. On addition of Ag(I), the enzyme-like activity is increasingly retained. A decrease in fluorescence and absorbance is not observed any longer.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3613_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Carboxylic acids (CAs) have been reported as potential biomarkers of specific diseases or human body odors. A visual sensor array is described here that is based on indicator displacement assays (IDAs). The arrays were prepared by spotting solutions of the following metal complexes: Murexide-Ni(II), murexide-Cu(II), zincon-Zn(II) and xylenol orange-Cu(II), with the capability of discrimination of 15 carboxylic acids (CAs) and the quantitation of pyruvic acid (PA). Clear differences can be observed through distinctive difference maps obtained within 5 min by subtraction of red, green and blue (RGB) values of digital images after and before exposure to analytes. After an analysis of multidimensional data by pattern recognition algorithms including HCA, PCA and LDA, excellent classification specificity, and accuracy of 〉96% were obtained for all samples. The IDA array exhibited a linear range from 10 to 1500 μM with a theoretical detection limit of 3.5 μM towards PA. Recoveries of real samples varied from 84.8% to 114.3%. As-fabricated IDA sensor array showed an excellent selectivity among other organic interfering substances and a good batch to batch reproducibility, demonstrating its robustness. All these observations suggested that the IDA sensor array is one of the most promising paths for the discrimination of CAs.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic diagram of indicator displacement assay (a), the procedure for acquisition of difference maps (b), and pattern recognitions for CAs (c). The method uses hierarchical cluster analysis (HCA), principal component analysis (PCA) and linear discriminant analysis (LDA)〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3601_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Carwash effluents contain potentially toxic chemical and microbiological pollutants which may pose public health and ecotoxicological threats if directly discharged into surface waters. This work was aimed at determining the microbiological, physicochemical, and toxicological parameters of carwash effluents. Toxicity assays were determined using whole effluent toxicity (WET) using 〈em〉Danio rerio〈/em〉 and 〈em〉Daphnia pulex〈/em〉. For microbiological analysis, sample aliquots were spread plated onto R2A Agar for the isolation of heterotrophic bacteria followed by DNA extraction from axenic cultures for sequencing analysis. The pH of effluent samples lay in the alkaline range, and ranged from pH 7 to pH 10. Sample salinity ranged from 0.2 to 0.3 g/Kg. Electrical conductivity values ranged from 274 to 554 μS/cm. Concentrations of Co, Pb, and Ni were 〈 1 mg/L in all samples while the concentrations of Cu ranged from 0.94 to 3.8 mg/L and Zn from 1.15 to 3 mg/L. Oil and grease concentrations ranged from 5 to 24 mg/L. The concentrations of TPH-GRO were low at 〈 1 mg/L in all samples. All the carwash effluents were categorised as acutely toxic, with ≥ 75% mortality recorded for both test organisms within the first 24 h of exposure to the test solutions. Heterotrophic bacteria counts ranged from 2800 to 4600 CFU/100 ml. Sequencing analysis revealed that 57% of the isolates were closely related to 〈em〉Aeromonas〈/em〉 species, with 43% closely related to 〈em〉Pseudomonas〈/em〉 species. We conclude that carwash effluents are veritable sources of microbiological contaminants and potentially toxic chemical pollutants of public health and ecotoxicological concern.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A multifunctional nanoprobe is described for dual sensing of acidic pH values and glutathione (GSH) by combining the pH-responsive fluorescent probe 3-acetyl-7-hydroxy-2H-chromen-2-one (AHC) and MnO〈sub〉2〈/sub〉 nanosheets. The fluorescence of the MnO〈sub〉2〈/sub〉/AHC composite is weak due to an inner filter effect. If, however, the MnO〈sub〉2〈/sub〉 nanosheets are reductively decomposed by GSH, the blue fluorescence of the pH probe AHC (with excitation/emission maximum at 417/456 nm) will be restored. The MnO〈sub〉2〈/sub〉 nanosheets also are decomposed by acidic pH values, and the fluorescence of AHC is decreased. According to absorbance and fluorescence signal changes, the pH and GSH induced responses can be easily distinguished. Thus, the nanoprobe can be used for logical analysis of acidic pH values and GSH. The nanoprobe works in the pH range from 4 to 7, and GSH can be determined in the concentration range from 0.5 to 200 μM.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of a multifunctional nanoprobe for dual sensing of acidic pH values and glutathione by combining a pH-responsive fluorescent probe and MnO〈sub〉2〈/sub〉 nanosheets. According to absorbance and fluorescence signal changes, the nanoprobe can be used for logical analysis.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3590_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Two kinds of aptasensors for ampicillin (AMP) are described. The assay strategies include the use of gold nanoparticles (AuNPs) that were modified with (a) a thiolated aptamer (T-Apt), and (b) a non-thiolated polyadenine aptamer (polyA Apt). The AuNPs and the aptamers were brought to interaction prior to addition of AMP. T-Apt and polyA Apt are adsorbed on the AuNPs by different mechanisms. The adsorbed aptamer was able to bind the target while preventing non-specific interactions. Remarkably different optical absorbances (measured at 520 and 680 nm) are produced the absence and presence of AMP. The assay can selectively recognize AMP even in the presence of species of similar chemical structure. The T-Apt based assay has a linear response in the 1–600 nM AMP concentration range and a 0.1 nM limit of detection. The respective data for the polyA Apt assay are 1–400 nM and 0.49 nM.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of the colorimetric aptasensor for ampicillin detection using two kinds of anti-ampicillin aptamers and gold nanoparticles. Polydiallyldimethylammonium chloride (PDDA) acts as aggregation agent.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3524_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The present study evaluated the concentration of six trace elements in processed meat products and in meat cuts. We also assessed the risk associated with the consumption of these foods based on the estimated daily intake (EDI) of these elements. Fifty-eight processed meat and 148 meat cuts samples were analyzed using ICP-OES. As and Cd were not detected in any sample of processed meat. The highest mean level of lead was observed in frankfurters (0.056 μg g〈sup〉−1〈/sup〉), which is half the maximum permissible level. For Cr, the highest mean concentrations were detected in chicken nuggets and beef hamburger (0.121 and 0.105 μg g〈sup〉−1〈/sup〉, respectively), which are above the allowed limit. The comparison between the impact of a diet restricted to processed meats with a diet restricted to meats cuts showed that the individuals following the latter are exposed to higher amounts of the trace elements analyzed.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In order to examine associations between asthma morbidity and local ambient air pollution in an area with relatively low levels of pollution, we conducted a time-series analysis of asthma hospital admissions and fine particulate matter pollution (PM〈sub〉2.5〈/sub〉) in and around Jackson, MS, for the period 2003 to 2011. Daily patient-level records were obtained from the Mississippi State Department of Health (MSDH) Asthma Surveillance System. Patient geolocations were aggregated into a grid with 0.1° × 0.1° resolution within the Jackson Metropolitan Statistical Area. Daily PM〈sub〉2.5〈/sub〉 concentrations were estimated via machine-learning algorithms with remotely sensed aerosol optical depth and other associated parameters as inputs. Controlling for long-term temporal trends and meteorology, we estimated a 7.2% (95% confidence interval 1.7–13.1%) increase in daily all-age asthma emergency room admissions per 10 μg/m〈sup〉3〈/sup〉 increase in the 3-day average of PM〈sub〉2.5〈/sub〉 levels (current day and two prior days). Stratified analyses reveal significant associations between asthma and 3-day average PM〈sub〉2.5〈/sub〉 for males and blacks. Our results contribute to the current epidemiologic evidence on the association between acute ambient air pollution exposure and asthma morbidity, even in an area characterized by relatively good air quality.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this study, Moderate Resolution Imaging Spectrometer (MODIS) satellite measurements of aerosol optical depth (AOD) from different retrieval algorithms have been correlated with ground measurements of fine particulate matter less than 2.5 μm (PM〈sub〉2.5〈/sub〉). Several MODIS AOD products from different satellites (Aqua vs. Terra), retrieval algorithms (Dark Target vs. Deep Blue), collections (5.1 vs. 6), and spatial resolutions (10 km vs. 3 km) for cities in the Western, Midwestern, and Southeastern USA have been evaluated. We developed and validated PM〈sub〉2.5〈/sub〉 prediction models using remotely sensed AOD data. These models were further improved by incorporating meteorological variables (temperature, relative humidity, precipitation, wind gust, and wind direction) from the North American Land Data Assimilation System Phase 2 (NLDAS-2). Adding these meteorological data significantly improved the simulation quality of all the PM〈sub〉2.5〈/sub〉 models, especially in the Western USA. Temperature, relative humidity, and wind gust were significant meteorological variables throughout the year in the Western USA. Wind speed was the most significant meteorological variable for the cold season while for the warm season, temperature was the most prominent one in the Midwestern and Southeastern USA. Using this satellite-derived PM〈sub〉2.5〈/sub〉 data can improve the spatial coverage, especially in areas where PM〈sub〉2.5〈/sub〉 ground monitors are lacking, and studying the connections between PM〈sub〉2.5〈/sub〉 and public health concerns including respiratory and cardiovascular diseases in the USA can be further advanced.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The effects of childhood exposure to ambient air pollution and their influences on healthcare utilization and respiratory outcomes in Memphis pediatric asthma cohort are still unknown. This study seeks to (1) investigate individual-level associations between asthma and exposure measures in high asthma rate and low asthma rate areas and (2) determine factors that influence asthma at first year of a child’s life, first 2 years, first 5 years, and during their childhood. Datasets include physician-diagnosed asthma patients, on-road and individual PM〈sub〉2.5〈/sub〉 emissions, and high-resolution spatiotemporal PM〈sub〉2.5〈/sub〉 estimates. Spatial analytical and logistic regression models were used to analyze the effects of childhood exposure on outcomes. Increased risk was associated with African American (AA) (odds ratio (OR) = 3.09, 95% confidence interval (CI) 2.80–3.41), aged 〈 5 years old (OR = 1.31, 95% 1.17–1.47), public insurance (OR = 2.80, 95% CI 2.60–3.01), a 2.5-km radius from on-road emission sources (OR = 3.06, 95% CI 2.84–3.30), and a 400-m radius from individual PM〈sub〉2.5〈/sub〉 sources (OR = 1.33, 95% CI 1.25–1.41) among the cohort with residence in high asthma rate areas compared to low asthma rates areas. A significant interaction was observed between race and insurance with the odds of AA being approximately five times (OR = 4.68, 95% CI 2.23–9.85), public insurance being about three times (OR = 2.65, 95% CI 1.68–4.17), and children in their first 5 years of life have more hospital visits than other age groups. Findings from this study can guide efforts to minimize emissions, manage risk, and design interventions to reduce disease burden.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The spatial distribution of the prevalence of asthma and chronic obstructive pulmonary disease (COPD) remains under the influence of a wide array of environmental, climatic, and socioeconomic determinants. However, a large proportion of these influences remain unexplained. In completion, this study examined the spatial associations between asthma/COPD morbidity and their determinants using ordinary least squares (OLS) and geographically weighted regressions (GWR). Inpatient records collected from the secondary and tertiary care hospitals in Kandy from 2010 to 2014 were considered as the dependent variable. Potential risk factors (explanatory variables) were identified in four distinguished classes: 1) meteorological factors, (2) direct and indirect factors of air pollution, (3) socioeconomic factors, and (4) characteristics of the physical environment. All possible combinations of candidate explanatory variables were evaluated through an exploratory regression. A comparison between the regression models was also explored. The best OLS regression models revealed about 55% of asthma variation and 62% of COPD variation while GWR models yielded 78% and 74% of the variation of asthma and COPD occurrences respectively. Relative humidity, proximity to roads (0–200 m), road density, use of firewood as a source of fuel, and elevation play a vital role in predicting morbidity from asthma and COPD. Both local and global regression models are important in assessing spatial relationships of asthma and COPD. However, the local models exhibit a better prediction capability for assessing non-stationary relationships of asthma and COPD than global models. The geostatistical aspects used in this study may also provide insights for evaluating heterogeneous environmental risk factors in other epidemiological studies across different spatial settings.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Understanding patients’ travel behavior for seeking hospital care is fundamental for understanding healthcare market and planning for resource allocation. However, few studies examined the issue comprehensively across populations by geographical, demographic, and health insurance characteristics. Based on the 2011 State Inpatient Database in Florida, this study modeled patients’ travel patterns for hospital inpatient care across geographic areas (by average affluence, urbanicity) and calendar seasons, and across subpopulations (by age, gender, race/ethnicity, and health insurance status). Overall, travel patterns for all subpopulations were best captured by the log-logistic function. Patients in more affluent areas and rural areas tended to travel longer for hospital inpatient care, so did the younger, whites, and privately insured. Longer travel distances may be a necessity for rural patients to cope with lack of accessibility for local hospital care, but for the other population groups, it may indicate rather better mobility and more healthcare choices. The results can be used in various healthcare analyses such as accessibility assessment, hospital service area delineation, and healthcare resource planning.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The authors describe an immunosensor for the prostate specific antigen (PSA). It was obtained by modifying a glassy carbon electrode (GCE) first modified with gold nanoparticles and then with reduced graphene oxide that was decorated with gold nanoparticles. The AuNPs on reduced graphene oxide provide a suitable surface for attachment of antibodies. On binding of the antigen, the square wave voltammetric signal (measured by using hexacyanoferrate as a probe) reduced. This method has two logarithmically linear analytical ranges that extend from 25 to 55 fg.mL〈sup〉−1〈/sup〉 and from 1 to 36 ng.mL〈sup〉−1〈/sup〉, respectively. The lowest detection limit is 2 pg.mL〈sup〉−1〈/sup〉. Electrochemical impedance spectroscopy was also carried out for PSA determination. EIS works in the 0.0018 to 41 ng.mL〈sup〉−1〈/sup〉 concentration range and has an LOD of 60 pg.mL〈sup〉−1〈/sup〉. This method was applied to the determination of PSA in (spiked) human serum samples. In order to survey the selectivity of immunosensor, determination of PSA was performed in human serum samples, and finally sensitivity and reproducibility were examined.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Facile label free immunosensor based on reduced graphene oxide decorated with gold nanoparticles for early diagnosis prostate cancer via ultrasensitive detection of PSA biomarker: application in human serum.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3565_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉To improve accuracy and efficiency of monitoring remediated sites, the current study proposed the use of bivariate linear mixed modelling and subsequent hypothesis testing to determine significant change in contaminant concentrations over time. The modelling method integrated soil heavy metal (arsenic–As, lead–Pb and zinc–Zn) concentrations obtained from Bicentennial Park, Sydney, Australia, in the years 1990 (〈em〉n〈/em〉 = 144) and 2015 (〈em〉n〈/em〉 = 60), alongside potential influencing factors as predictor variables. Following variable selection, significant predictors included As (1990)—plan curvature, land cover change; As (2015)—multi-resolution ridge top flatness (MRRTF); Pb (1990)—elevation, MRRTF, type of nearest road; Pb (2015)—land cover change; Zn (1990)—distance to the nearest road and road type; and for Zn (2015)—aspect and land cover change. Model quality statistics (standardised squared prediction error; SSPE) indicated relatively good estimates of the prediction variance (mean ~ 1.0 for all metals, median = 0.512 for As (1990), 0.420 for As (2015), 0.417 for Pb (1990), 0.388 for Pb (2015), 0.342 for Zn (1990) and 0.263 for Zn (2015)), however Lin’s concordance correlation coefficient indicated poor prediction of point estimates (LCCC = 0.263 for As (1990), 0.414 for As (2015), 0.250 for Pb (1990), 0.166 for Pb (2015), 0.233 for Zn (1990) and 0.408 for Zn (2015)). Pb in 1990 exceeded the Australian guide value of 600 mg kg〈sup〉−1〈/sup〉 in small, isolated areas of the park, and by 2015, these ‘hotspots’ had significantly diminished (〈em〉P〈/em〉 〈 0.05). Concentrations of As were low in both 1990 and 2015, not exceeding the 300 mg kg〈sup〉−1〈/sup〉 guide; yet, in 2015, As had significantly increased in the south of the study area (〈em〉P〈/em〉 〈 0.2). Zn concentrations in 1990 were elevated but did not exceed the guide value of 30,000 mg kg〈sup〉−1〈/sup〉. Overall, the models exhibited good estimation of prediction variance and therefore are suitable for hypothesis testing; however, they exhibited poor prediction quality at times. Despite this, bivariate linear mixed modelling is worth exploring as it provides an advantage over modelling single time points and can assist with tracking potential contaminant sources before they cause harm.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Dengue is among the largest public health problems in Brazil. Reported dengue cases via DATASUS were correlated with reanalysis data from NCEP (rainfall and air temperature) and Brazil’s population data (2000 and 2010) from 1994 to 2014. The aim of this study was to evaluate relational patterns between climate variables together with population data from the last census and reported cases of dengue in Brazil from 1994 to 2014 by using statistical techniques. Several statistical methods [descriptive and exploratory statistics; simple and multiple linear regressions; Mann–Kendall (MK), Run, and Pettit nonparametric tests; and multivariate statistics via cluster analysis (CA)] were applied to time series. The highest percentages of Dengue cases were in Brazil’s Southeast (47.14%), Northeast (29.86%), and Central West (13.01%). Upon CA of the Brazilian regions, three homogeneous dengue groups were formed: G〈sub〉1〈/sub〉 (North and Central West), G〈sub〉2〈/sub〉 (Southeast and Northeast), and G〈sub〉3〈/sub〉 (South). Run testing indicated that the time series is homogenous and persistence free. MK testing showed a nonsignificant trend of increase of dengue cases in 23 states with positive trends and in four states with negative trends of Brazil. A significant increase in the magnitude of dengue at the regional level was recorded in the North, Southeast, South, and Central West regions. Statistical methods showed that dengue variability in Brazil is cyclical (2- to 3-year cycles), but not repetitive of El Niño-Southern Oscillation (ENSO) in the moderate, strong, and neutral categories. ENSO interferes with the action of weather systems, changing or intensifying rainfall and air temperatures in Brazil. The population increase in recent decades and the lack of effective public policies together with the action of ENSO contributed to the increase in dengue cases reported in Brazil.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Given the spatial and temporal variability in hydrological conditions and nitrogen (N) processes, it is of great uncertainty to identify the N sources and evaluate N transformation processes in the upper Han River. Investigations were conducted in November 2015 and January, April, and July 2016, using an isotopic method and water quality monitoring. The significant and positive correlation between NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 concentrations and Cl〈sup〉−〈/sup〉 (〈em〉p〈/em〉 〈 0.01) in most sampling months suggested that the great influence of human activities and sewage or manure was the dominant NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 source. The δ〈sup〉15〈/sup〉NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 values and NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉/Cl〈sup〉−〈/sup〉 variations indicated that riverine N mainly came from soil organic N and sewage in November. Fertilizer and sewage were the major N sources in January and April, respectively. In July, water was influenced by various N inputs. The nitrification process played an important role in the low δ〈sup〉15〈/sup〉NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 values in January, while both nitrification and plant uptake resulted in the increase in δ〈sup〉15〈/sup〉NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 values in April. The simultaneous effect of N fixation and plant uptake maintained the stabilization of δ〈sup〉15〈/sup〉NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 concentrations. Our study provides theoretical basis on N sources and transformations for controlling N pollution and improving water quality in the upper Han River in the near future.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Concentrations of arsenic, nickel and chromium in sediments of the nearshore Pilbara Region of Western Australia’s mid -north coast have caused concerns to regulators issuing ocean disposal permits for many years. A meta-analysis of data from a large number of surveys, conducted in support of permit applications over many years and across hundreds of kilometres of coastline, shows that, when assessed as total metal concentrations, chromium and nickel occur routinely at concentrations above those recommended as screening triggers by national guidelines and arsenic more rarely. Arsenic was concentrated in surface sediments, consistent with an organic origin. Concentrations of nickel and chromium were higher in deeper sediment layers, consistent with a natural geological origin. However, sediment particle sizing was a major determinant of total metal concentrations of all three metals, and bioavailability was always much lower and within recommended guidelines. Past dredging activity for channels and berths in the large ports of the Pilbara has most likely led to an elevation of fine fractions of surface sediments within operating port areas, when compared to the undisturbed surrounding areas, and may also have increased the proportion of sediment from deeper substrates at the surface. Whilst total concentrations of chromium and nickel commonly exceed screening guidelines throughout the nearshore Pilbara Region, their bioavailability was low and these metals present a little threat to biota.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A non-enzymatic hydrogen peroxide (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉) electrochemical sensor material was prepared from silver nanoparticles and a 2D copper-porphyrin framework (MOF). The structure and morphology of the nanocomposite were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The results showed that the MOF has a two-dimensional sheet structure, and a large number of Ag NPs are uniformly attached to it. The MOF also acts as a peroxidase mimic. The sensor has excellent catalytic performance in terms of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 reduction. Figures of merit include (a) an electrochemical sensitivity of 21.6 μA mM〈sup〉−1〈/sup〉 cm〈sup〉−2〈/sup〉 at a typical working potential of −0.25 V (vs. SCE), (b) a detection limit of 1.2 μM (at S/〈em〉N〈/em〉 = 3), and (c) a linear response range that extends from 3.7 μM to 5.8 mM. Compared to other sensors of the same type, the linear range of the sensor is extended by an order of magnitude.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Silver nanoparticles (Ag NPs) were reduced with sodium borohydride (NaBH〈sub〉4〈/sub〉) on the surface of copper(II)-porphyrin (Cu-TCPP) nanosheets prepared with the assistance of polyvinylpyrrolidone (PVP). Their synergistic effect improved the performance of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 sensor fabricated by immobilizing Ag NPs/Cu-TCPP nanocomposites on glassy carbon electrodes (GCE).〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3551_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Two adsorbents with covalently bound aminomethylenephosphonic acid functions (and referred to as MNPs/AMPA and MNPs/SiO〈sub〉2〈/sub〉-AMPA) were synthesized from two types of amino-functionalized magnetic nanoparticles (MNPs) via Moedritzer-Irani reaction. The sorbents with anchored dopamine ligand (MNPs/dopa) or aminopropyl groups (MNPs/SiO〈sub〉2〈/sub〉-NH〈sub〉2〈/sub〉), and the MNPs/AMPA were characterized by X-ray diffraction, FTIR, transmission electron microscopy and vibrating sample magnetometry. Surface modification does not adversely impact the physical properties of the starting magnetite. Compared to the size of the unmodified Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 (magnetite) nanoparticles (7–12 nm), the average size of functionalized nanoparticles is increased to 10–16 nm. Similarly, the magnetic saturation decreased from 67.5 emu g〈sup〉-1〈/sup〉 to 42.0 emu g〈sup〉−1〈/sup〉, and the surface area is increased up to 205 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉 for MNPs/SiO〈sub〉2〈/sub〉-AMPA. The kinetics of the adsorption of Eu(III) on the sorbent is ultra-fast, and equilibria are attained within 5–10 min at room temperature. The adsorption kinetics can be described by a pseudo-second-order model. Adsorption and desorption conditions were tested with respect to the removal of Eu(III) ions from water solution. The adsorption capacities for Eu(III) at pH 7.0 are 77 mg g〈sup〉−1〈/sup〉 and 69 mg g〈sup〉−1〈/sup〉 for MNPs/AMPA and MNPs/SiO2-AMPA nanoparticles, respectively. Eu(III) was quantified by ICP-MS. The limit of detection (LOD) for Eu(III) is 0.05 ng L〈sup〉−1〈/sup〉 (based on the 3σ criterion), with an enrichment factor of 150. The selectivity over ions such as Tb(III), Fe(III), Zn(II), Cu(II), and Ca(II) ions was studied. Under optimal condition the distribution coefficient for Eu(III) relative to these ions is near 10〈sup〉5〈/sup〉 mL g〈sup〉−1〈/sup〉. The sorbents can be easily retrieved from even large volumes of aqueous solutions by magnetic separations. The method was tested for spiked water samples (with recoveries from 96.6–102.5%) and for rock minerals.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉A schematic showing the regeneration of magnetite nanoparticles (MNPs), core-shell (MNPs/SiO〈sub〉2〈/sub〉), and the structures with covalently bonded aminomethylenephosphonic acid (AMPA) after preconcentration of Eu(III) from largewater sample volumes onto a small specimen.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3520_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A ratiometric electrochemical aptamer-based assay is described for the ultrasensitive and highly specific determination of adenosine triphosphate (ATP). It is based on ATP aptamer-mediated triple-helix molecular switch (THMS). The method uses (a) a hairpin DNA (MB-DNA-SH) labeled with the redox probe Methylene Blue (MB) at the 3′ end, and a thiol group at the 5′ end, and (b) a single strand ATP aptamer modified with two ferrocenes at each end (Fc-DNA-Fc). The labeled probe of type MB-DNA-SH was self-assembled onto the surface of a gold electrode via gold-thiol binding. On exposure to Fc-DNA-Fc, it will hybridize with MB-DNA-SH to form a stable THMS structure on electrode surface. In the presence of ATP, it hybridizes with the loop portion of Fc-DNA-Fc, and this results in the unwinding of the THMS structure. Such variation caused the changes of the differential pulse voltammetry (DPV) peak currents of both MB (at around −0.25 V) and Fc (at around 0.39 V; both vs. Ag/AgCl). A significant enhancement is found for the ratio of the two DPV peaks. Under the optimum experimental conditions, this assay has a response that covers the 0.05 to 100 pM ATP concentration range, and the detection limit is 5.2 fM (for 〈em〉S〈/em〉/〈em〉N〈/em〉 = 3). The method is highly selective for ATP over its analogs.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of a novel ratiometric electrochemical aptasensor for ATP via triple-helix molecular switch (THMS) strategy. MB-DNA-SH was self-assembled on GE surface through gold-thiol binding. Fc-DNA-Fc hybridized with MB-DNA-SH to form THMS structure. ATP specifically bond with its aptamer sequence of Fc-DNA-Fc to unwind the THMS structure. The ratio of DPV peak currents of MB and Fc was applied to monitor the concentration of ATP in real samples over its analogs.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3630_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Core-shell nanoparticles (NPs) consisting of a gold core and a metal-organic framework shell (type MOF-74) were synthesized via one-pot synthesis. The NPs exhibit highly sensitive and stable SERS activity for the detection of 4-nitrothiophenol, with a specific band at 1337 cm〈sup〉−1〈/sup〉. The method has a linear response in 0.10–10 μmol·L〈sup〉−1〈/sup〉 analyte concentration range and a lower detection limit of 69 nmol·L〈sup〉−1〈/sup〉. The potential application of this novel SERS substrate was evaluated by two model reactions involving 4-nitrothiophenol. The first involves in-situ SERS monitoring of the surface plasmon-induced nitration of aromatic rings without adding conventional acid catalyst. The second involves the photocatalytic reduction of 4-nitrothiophenol to 4-thioaminophenol in the presence of Au/MOF-74 under 785-nm laser irradiation. The plasmon-assisted dimerization of 4-nitrothiophenol to form 4,4′-dimercaptoazobenzene can also be monitored simultaneously.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of a nanoparticle SERS substrate consisting of gold core and MOF-74 shell, which was applied to detection of 4-nitrothiophenol. The Au/MOF-74 was successfully used for in-situ monitoring of two model reactions involving 4-nitrothiophenol by SERS.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3618_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉PM〈sub〉2.5〈/sub〉 air pollution is a significant issue for human health all over the world, especially in East Asia. A large number of ground-based measurement sites have been established over the last decade to monitor real-time PM〈sub〉2.5〈/sub〉 concentration. However, even this enhanced observational network leaves many gaps in characterizing the PM〈sub〉2.5〈/sub〉 spatial distribution. Machine learning provides a variety of algorithms to help deal with these large spatial gaps—combining both remotely sensed and in situ observation data to estimate the global PM〈sub〉2.5〈/sub〉 concentration. This study used a PM〈sub〉2.5〈/sub〉 data product of six regions from the results of an unsupervised self-organizing map (SOM) with optimized ensemble learning approaches to highlight the most important meteorological and surface variables associated with PM〈sub〉2.5〈/sub〉 concentration. These variables were then examined via multiple linear regression models to provide physical mechanistic insights into the morphology of the PM〈sub〉2.5〈/sub〉 annual cycles.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Heatwaves are one of the deadliest natural disasters that occur annually with thousands of people seeking medical attention. The spatio-temporal synchronization between peaks in disease manifestation and high temperature provides important insights into the seasonal timing of the heatwave and the response it may cause with respect to emergence, severity, and duration. The objectives of this study are to examine the association between hospitalizations due to heat stroke in older adults and heat in the United States (US) and explore synchronization with respect to heatwave sequence, time of arrival, and regional climate. Three large data sets were utilized: daily hospitalization records of the US elderly between 1991 and 2006, annual demographic summaries on Medicare beneficiaries maintained by the Centers for Medicare and Medicaid Services (CMS), and nationwide daily meteorological observations. We modeled seasonal fluctuations in health outcomes, such as the timing and intensity of the seasonal peak in hospitalizations using refined harmonic GLM for eight climatically similar regions. During the 16-year study period, there were 40,019 heat-related hospitalizations (HRH) in the conterminous  US. The rates of HRH varied substantially across eight climatic regions: with the highest rate of 7.05 cases per million residents observed in areas with temperate arid summers and winters (TaTa) and the lowest rate of 0.67—in areas with cold moderately dry summers and arid winters (CdCa), where summer temperatures are about  18.3 °C and 12.1 °C, respectively. We detected 400 heatwaves defined as any day when the night time temperature is above its 90th percentile for the current and previous nights. The first seasonal heatwave in a season resulted in 4274 hospitalizations over 342 heatwave-days: 34.3% of 12,442 hospitalizations occurred in 26% of 1308 heatwave-days. The relative risks of increased HRH associated with the first and second heatwaves were 10.4 (95%CI: 8.5; 12.3) and 11.4 (95%CI: 9.6; 13.3), respectively, indicating the disproportional effects of early heatwave arrivals. The seasonal spike in heat stroke hospitalizations in regions with relatively similar annual temperatures, e.g. in areas with temperate moderately dry summers and winters (TdTa: 12.8 °C) and (TaTa: 11.1 °C) ranged between 4.5 (95%CI: 3.3; 5.5) and 11.0 (95%CI: 8.2; 14.9) cases per million residents, respectively, indicating substantial regional differences. The differences in heat-related hospitalizations and response to heatwaves are substantial among older adults residing in different climate regions of the conterminous US. The disproportionally high response to the early seasonal heatwave deserves special attention, especially in the context of prevention and decision support frameworks.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Visceral leishmaniasis is a public health problem in Brazil. This disease is endemic in most of Bahia state, with increasing reports of cases in new areas. Ecological niche models (ENM) can be used as a tool for predicting potential distribution for disease, vectors, and to identify risk factors associated with their distribution. In this study, ecological niche models (ENMs) were developed for visceral leishmaniasis (VL) cases and 12 sand fly species captured in Bahia state. Sand fly data was collected monthly by CDC light traps from July 2009 to December 2012. MODIS satellite imagery was used to calculate NDVI, NDMI, and NDWI vegetation indices, MODIS day and night land surface temperature (LST), enhanced vegetation index (EVI), and 19 Bioclim variables were used to develop the ENM using the maximum entropy approach (Maxent). Mean diurnal range was the variable that most contributed to all the models for sand flies, followed by precipitation in wettest month. For 〈em〉Lutzomyia longipalpis〈/em〉 (〈em〉L. longipalpis〈/em〉), annual precipitation, precipitation in wettest quarter, precipitation in wettest month, and NDVI were the most contributing variables. For the VL model, the variables that contributed most were precipitation in wettest month, annual precipitation, LST day, and temperature seasonality. 〈em〉L. longipalpis〈/em〉 was the species with the widest potential distribution in the state. The identification of risk areas and factors associated with this distribution is fundamental to prioritize resource allocation and to improve the efficacy of the state’s program for surveillance and control of VL.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Light-harvesting nanoprobes were developed by self-assembly of nanoscale metal-organic frameworks (NMOFs) and stimuli-responsive polymers for fluorometric sensing of pH values and temperature. Two kinds of fluorescent NMOFs (acting as the energy donor) and stimuli-responsive polymers conjugated to fluorophores (acting as energy acceptors) were prepared and characterized. The NMOFs include zirconium(IV) and 〈em〉π〈/em〉-conjugated dicarboxylate ligands. The fluorophores inclued cyaine dyes and a Bodipy dye. The energy donor and energy acceptor form a Förster resonance energy transfer (FRET) nanosystem. In the light-harvesting system, the chain lengths of the stimuli-responsive polymers vary when the local pH value or temperature change. Ratiometric sensing of pH and temperature was accomplished by monitoring fluorescence. pH values were can be sensed between 3.0 and 8.0 under 420 nm excitation and by ratioing the emission peaks at 645 and 530 nm. Temperature can be sensed in the range from 25 to 50 °C under 550 nm excitation and by ratioing the emission peaks at 810 and 695 nm. The nanoprobes display excellent water dispersibility and cell membrane permeability. They were applied to image pH values and temperature in HeLa cells.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of an effective strategy to fabricate light-harvesting nanoprobes by self-assembly of MOFs and stimuli-responsive polymers for ratiometric pH and temperature sensing. The distance as the polymer length between energy donor and acceptor is crucial for energy transfer efficiency.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3608_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A paper-based electrochemical sensor is described that is based on the use of thiol-terminated poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC-SH) that was self-assembled on a gold nanoparticle-modified screen-printed electrode (SPE). The SPE sensor was used for label-free detection of C-reactive protein (CRP). Gold nanoparticles (AuNPs) were first electrodeposited on the SPCE, followed by the self-assembly of PMPC-SH on gold. The electrochemical response of the modified SPE to CRP was measured by differential pulse voltammetry (DPV). If the CRP on the paper device is contacted with Ca (II) ions, the current (measured by using hexacyanoferrate as the electrochemical probe) decreases. The signal drops in the 5 to 5000 ng·mL〈sup〉−1〈/sup〉 CRP concentration range, and the lower detection limit (at 3 SD/slope) is 1.6 ng·mL〈sup〉−1〈/sup〉. The use of a PMPC-modified surface also reduces the nonspecific adsorption of proteins. The sensor is not interfered by bilirubin, myoglobin and albumin. It was successfully applied to CRP detection in certified human serum. This sensor is applicable as an attractive protocol for an inexpensive, highly sensitive, and disposable material for electrochemical detection of CRP.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of highly sensitive and disposable paper-based electrochemical sensor using thiol-terminated poly(2-methacryloyloxyethyl phosphorylcholine) in the presence of Ca〈sup〉2+〈/sup〉 for the label-free C-reactive protein detection. The current was measured by differential pulse voltammetry.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3559_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A sandwich-type electrochemical aptasensor is described for detecting the carcinoembryonic antigen (CEA) with high sensitivity and accuracy. Two kinds of nanomaterials are used. The first was obtained by modifying gold nanoparticles with reduced graphene oxide and hemin (Hemin-rGO-AuNPs). The second consists of horseradish peroxidase-modified organic-inorganic hybrid nanoflowers linked to gold nanoparticles to obtain an architecture of type HRP-Cu〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉-HNF-AuNPs). These serve as carriers for two aptamers (apt1 and apt2) against CEA. Simultaneously, they were used to catalyze the precipitation reaction between 4-chloro-1-naphthol(4-CN) and H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. A sandwich-type assay linked to enzyme inhibition amplification was established for electrochemical determination of CEA. Under optimal experimental conditions and by using differential pulse voltammetry, the response peak currents (best measured at −0.34 V vs. Ag/AgCl) increases linearly with the logarithm of the CEA concentration in the range between 100 fg mL〈sup〉−1〈/sup〉 and 100 ng mL〈sup〉−1〈/sup〉. The detection limit is as low as 29 fg mL〈sup〉−1〈/sup〉.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of the sandwich-type electrochemical aptasensor based on signal inhibition amplification from biocatalytic precipitation reaction. (HRP-Cu〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉 hybrid nanoflowers: Horseradish Peroxidase-Cu〈sub〉3〈/sub〉(PO〈sub〉4〈/sub〉)〈sub〉2〈/sub〉 hybrid nanoflowers; AuNPs: Gold Nanoparticles; Hemin-rGO-AuNPs: Hemin-Reduced Graphene Oxide-Gold Nanoparticles; BSA: Bovine Serum Albumin; CEA: Carcinoembryonic Antigen; CEA〈sub〉apt1〈/sub〉: 5′-SH-(CH〈sub〉2〈/sub〉)〈sub〉6〈/sub〉-ATA CCA GCT TAT TCA ATT-3′; CEA〈sub〉apt2〈/sub〉: 5′-NH〈sub〉2〈/sub〉-(CH〈sub〉2〈/sub〉)〈sub〉6〈/sub〉-AGG GGG TGA AGG GAT ACC C-3′; GCE: Glassy carbon electrode; 4-CN: 4-Chloro-1-naphthol; DPV: Differential pulse voltammetry).〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3542_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Polyaniline and its composites with nanoparticles have been widely used in electrochemical sensor and biosensors due to their attractive properties and the option of tuning them by proper choice of materials. The review (with 191 references) describes the progress made in the recent years in polyaniline-based biosensors and their applications in clinical sensing, food quality control, and environmental monitoring. A first section summarizes the features of using polyaniline in biosensing systems. A subsequent section covers sensors for clinical applications (with subsections on the detection of cancer cells and bacteria, and sensing of glucose, uric acid, and cholesterol). Further sections discuss sensors for use in the food industry (such as for sulfite, phenolic compounds, acrylamide), and in environmental monitoring (mainly pesticides and heavy metal ions). A concluding section summarizes the current state, highlights some of the challenges currently compromising performance in biosensors and nanobiosensors, and discusses potential future directions.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of electrochemical sensor and biosensors applications based on polyaniline/nanoparticles in various fields of human life including medicine, food industry, and environmental monitoring. The simultaneous use of suitable properties polyaniline and nanoparticles can provide the fabrication of sensing systems with high sensitivity, short response time, high signal/noise ratio, low detection limit, and wide linear range by improving conductivity and the large surface area for biomolecules immobilization.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3588_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉New green-emissive carbon dots (G-CDs) are described here and shown to be viable fluorescent nanoprobes for the detection of changes in cellular pH values. By using 〈em〉m〈/em〉-phenylenediamine as the carbon source, G-CDs with an absolute quantum yield of 36% were solvothermally synthesized in the presence of strong H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉. The G-CDs have an average size of 2.3 nm and display strong fluorescence with excitation/emission peaks at 450/510 nm. The fluorescence intensity depends on the pH value in the range from 6.0 to 10.0, affording the capability for sensitive detection of intracellular pH variation. The nanosensor with excellent photostability exhibited good fluorescence reversibility in different pH solutions, and showed excellent stability against the influence of other biological species. The nanoprobe was successfully used in confocal fluorescence microscopy to determine pH values in SMMC-7721 cells.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of green-emissive carbon dots (G-CDs) synthesized using 〈em〉m〈/em〉-phenylenediamine and sufuric acid through a solvothermal method for real-time fluorometric monitoring of intracellular pH values. Mechanism can be ascribed to PET process from the electron lone pair in amino group to the CDs.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3569_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉An ultrasensitive and highly reliable ratiometric assay is described for the determination of microRNA-155. It works at the attomolar concentration level and has high selectivity which warrants its potential application in cancer biomarker tracking. The excellent performance of this method results from (a) the use of a hybrid conjugate prepared from Rhodamine B (RhB), carbon dots (CDs) and probe-microRNA, and (b) from the measurement of fluorescence resonance energy transfer (FRET) that is observed in the AuNP/target-microRNA system as a result of RNA hybridization. The dye RhB (emission peak at 580 nm) serves as an internal reference. The sensitivity of this assay is increased by about 30% because of the broad emissions of CDs (489 nm and 665 nm) through a sequential FRET phenomenon. RhB-CDs were covalently bio-conjugated to probe microRNA. In the presence of AuNPs, the fluorescence of the CDs is quenched, while in the presence of microRNA-155, the ratio of fluorescences at 489 and 665 nm (I〈sub〉489〈/sub〉/I〈sub〉665〈/sub〉) is enhanced again. A linear relationship exists between the ratio of fluorescence and the concentration of microRNA-155 in the range from 1 aM to 0.1 μM, and the detection limit is 0.3 aM. The assay was applied to quantitative studies of target microRNA-155 in multiple pathways associated with cancer progression in biological fluids include human serum samples and cancer cells. The nanoprobe also deliver clear signal to microRNA target in fixed and lived MDA-MB-231 cells.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉A ratiometric FRET sensing method used for microRNA-155 detection at aM concentration level using CDs and AuNPs as donor–acceptor respectively and Rhodamine B as amplification reagent. The application of assay for imaging of microRNA-155 in fixed and live MDA-MB-231 cells is demonstrated.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3446_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉An amperometric nonenzymatic dopamine sensor has been developed. Cobalt oxide (Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉) nanoparticles were uniformly dispersed inside mesoporous SiO〈sub〉2〈/sub〉/C. A sol-gel process was used for the preparation of this mesoporous composite material (SiO〈sub〉2〈/sub〉/C). This mesoporous composite has a pore size of around 13–14 nm, a large surface area (S〈sub〉BET〈/sub〉 421 m〈sup〉2〈/sup〉·g〈sup〉−1〈/sup〉) and large pore volume (0.98 cm〈sup〉3〈/sup〉·g〈sup〉−1〈/sup〉) as determined by the BET technique. The material compactness was confirmed by SEM images which showing that there is no phase segregation at the magnification applied. The chemical homogeneity of the materials was confirmed by EDX mapping. The SiO〈sub〉2〈/sub〉/C/Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanomaterial was pressed in desk format to fabricate a working electrode for nonenzymatic amperometric sensing of dopamine at a pH value of 7.0 and at a typical working potential of 0.25 V vs SCE. The detection limit, linear response range and sensitivity are 0.018 μmol L〈sup〉−1〈/sup〉, 10–240 μmol L〈sup〉−1〈/sup〉, and 80 μA·μmol L〈sup〉−1〈/sup〉 cm〈sup〉−2〈/sup〉, respectively. The response timé of the electrode is less than 1 s in the presence of 60 μmol L〈sup〉−1〈/sup〉 of dopamine. The sensor showed chemically stability, high sensitivity and is not interfered by other electroactive molecules present in blood. The repeatability of this sensor was evaluated as 1.9% (RSD; for 〈em〉n〈/em〉 = 10 at a 40 μmol L〈sup〉−1 〈/sup〉dopamine level.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of the preparation of a nanostructured composite of type SiO〈sub〉2〈/sub〉/C/Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 for electrooxidative sensing of dopamine.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3605_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Using the sub-seasonal to seasonal forecast model of Beijing Climate Center, several key physical parameters are perturbed by the Latin hypercube sampling method to find a better configuration for representation of Madden–Julian oscillation (MJO) in the free-run simulation. We find that although model simulation is especially sensitive to some parameters, there are overall no significant linear relationships between model skill and any one of the parameters, and the optimum performance can be obtained by combined perturbations of multiple parameters. By optimization, MJO’s spectrum, intensity, spatial structure and propagation, as well as the mean state and variance, are all improved to some extent, suggesting the correspondence and interrelation of model’s performances in simulating different characteristics of MJO. Further, several sets of initialized hindcasts using the optimized parameters are conducted, and their results are compared with the hindcasts using only improved initial conditions. We show that with an optimized model, the forecast of MJO beyond 3-week lead time is not improved, and the maximum useful skill is only slightly increased, implying that a decrease of model error does not always translate into an increase of forecast skill at all lead time. However, the skill is obviously enhanced during lead times of 2–3 weeks for forecasts in most seasons and initial phases except for a few cases. Particularly, the deficiency in forecasting MJO’s propagation from the Indian Ocean to the Pacific is relieved, further highlighting the positive contribution of reducing model error compared to previous work that only reduced initial condition error. In this study, we also show benefits of multi-scheme ensemble strategy in describing uncertainties of model error and initial condition error and thus improving MJO forecast.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The accurate characterization of seasonal and inter-annual site-level wind energy variability is essential during wind project development. Understanding the features and probability of low-wind years is of particular interest to developers and financers. However, a dearth of long-term, hub-height wind observations makes these characterizations challenging, and thus techniques to improve these characterizations are of great value. To improve resource characterization, we explicitly link wind resource variability (at hub-height, and at specific sites) to regional and synoptic scale wind regimes. Our approach involves statistical clustering of high-resolution modeled wind data, and is applied to California for a period covering 1980–2015. With this approach, we investigate the unique meteorological patterns driving low and high wind years at five separate wind project sites. We also find wind regime changes over the 36-year period consistent with global warming: wind regimes associated with anomalously hot summer days increased at half a day per year and stagnant conditions increased at one-third days per year. Despite these changes, the average annual resource potential remained constant at all project sites. Additionally, we identify correlations between climate modes and wind regime frequency, a linkage valuable for resource characterization and forecasting. Our general approach can be applied in any location and may benefit many aspects of wind energy resource evaluation and forecasting.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A new set of CORDEX simulations over South America, together with their coarser-resolution driving Global Climate Models (GCMs) are used to investigate added value of Regional Climate Models (RCMs) in reproducing mean climate conditions over the continent. There are two types of simulations with different lateral boundary conditions: five hindcast simulations use re-analysis as boundary conditions, and five other historical simulations use GCMs outputs. Multi-model ensemble means and individual simulations are evaluated against two or three observation-based gridded datasets for 2-m surface air temperature and total precipitation. The analysis is performed for summer and winter, over a common period from 1990 to 2004. Results indicate that added value of RCMs is dependent on driving fields, surface properties of the area, season and variable considered. A robust added value for RCMs driven by ERA-Interim is obtained in reproducing the summer climatology of surface air temperature over tropical and subtropical latitudes. Mixed results can be seen, however, for summer precipitation climatology in both hindcast and historical experiments. For winter, there is no noticeable improvement by the RCMs for the large-scale precipitation and surface air temperature climatology. To further understand the added value of RCMs, models deviations from observation are decomposed according to different terms that reflect the observational uncertainty, the representativeness error, the interpolation error, and the actual performance of the model. Regions where these errors are not negligible, such as in complex terrain regions, among others, can be identified. There is a clear need for complementary assessment to understand better the real value added by RCMs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The model fidelity in simulating the Northern Hemisphere storm track interannual variability and the connections of this variability to the low frequency atmospheric variations and oceanic variations are examined based on the atmospheric European Centre for Medium-Range Weather Forecasts (ECMWF) model and coupled NCAR Community Climate System Model (CCSM) systems at different horizontal resolutions. The atmospheric general circulation model (AGCM) runs are forced by observed sea surface temperatures (SST) with varying atmospheric resolutions, while the coupled general circulation model (CGCM) runs have a fixed atmospheric resolution but varying oceanic resolutions. The phases, between the North Pacific (NP) and North Atlantic (NA) sectors, of the simulated hemisphere-scale Empirical Orthogonal Function (EOF) modes of the storm track fluctuations change with the model resolution, suggesting the storm track variability in NP and NA basins are largely independent. The models can qualitatively reproduce the basin-scale EOFs of both NP and NA storm track variability. These EOFs are not sensitive to either atmospheric or oceanic model horizontal resolutions, but their magnitudes from the CGCM runs are substantially underestimated. The storm track variations over NP basin are hybrid of internal atmospheric variations and external forcing from the underlying conditions, but the fluctuations over the NA basin are merely atmospheric internal variability. The NP storm track variability from SST forcing accounts for 4.4% of the total variance in observations, while it only has less than 2% of the total in all AGCM simulations. The external forcing to the storm track variations is more realistically reproduced in the higher atmospheric resolution runs. The air–sea coupling makes the SST feedbacks to the atmospheric internal variability, absent in the atmospheric ECMWF model hindcasts, emerge in the coupled CCSM simulations.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Urban land use in East China has undergone considerable change since the 1990s. How such change affects both in situ and remote climate conditions is investigated through numerical modelling experiments with the Community Atmosphere Model Version 5.1. The results show that urbanization causes an increase in surface temperature due to reduced surface albedo but a decrease in specific humidity due to locally reduced surface evaporation. The change in specific humidity overwhelms the surface temperature change effect, leading to locally reduced precipitation. It is noted that urbanization causes changes in climate conditions not only locally but also remotely. Anomalous low-level divergence associated with the reduced precipitation in situ prevents the northward progression of the East Asian summer monsoon. As a result, the major monsoon rain band is strengthened and confined over South China and the tropical Asian monsoon zone along 12°–25°N. The increase of rainfall in the tropical zone, on one hand, induces the local overturning cell, leading to anomalous subsidence over mid-latitude Asia and the equatorial zone, and, on the other hand, perturbs the Subtropical Jet, generating a Rossby wave train disseminating along the Jet. Both of these processes cause anomalous dry and hot conditions over mid-latitude Asia.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Uncertainties in future changes of temperature and precipitation over the homogenous monsoon regions of India are investigated using the CMIP5 and CESM-LE datasets. The uncertainty is partitioned into epistemic (model) and aleatoric (internal variability) components for each season using the RCP8.5 scenario. The uncertainty in temperature change is dominated by epistemic uncertainty that increases over time. The uncertainty in precipitation change shows a more complex picture. Aleatoric uncertainty can remain quite large and comparable to epistemic uncertainty till the latter part of the twenty-first Century especially during the JJA and SON seasons. Much of the rainfall uncertainty is in the more arid Northwest region with the West Central region (part of the core monsoon area) exhibiting lower uncertainties. Considerable increase in rainfall is seen during the SON season indicating an extended monsoon season. During the DJF season aleatoric uncertainty is much larger than epistemic uncertainty over much of the century and shows considerable decadal scale variability. Using the 40-member CESM-LE ensemble to analyze the influence of ensemble size on aleatoric uncertainty we find that low ensemble sizes can lead to an underestimate of the uncertainty.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this study, we investigate the role of the Asian summer monsoon (ASM) anticyclone in the distribution of ozone over the southern India and tropical Indian Ocean. We present the horizontal and vertical structure of ozone in the upper troposphere and lower stratosphere (UTLS) region. The analysis shows that the region within the ASM anticyclone has low ozone, and high tropopause altitude, as compared to the region outside the anticyclone during boreal summer. The southern edge of the ASM anticyclone, i.e. the southern India and tropical Indian Ocean show a remarkably high ozone concentration in the UTLS region during summer. Analysis of daily fields shows that ozone concentration in the upper troposphere over the southern India and tropical Indian Ocean increases with the strength of the tropical easterly jet, which is an outcome of ASM circulation. Different mechanisms responsible for the ozone enhancement in the UTLS region over the tropical Indian region have been discussed in this paper. The in situ ozonesonde observations from six Indian stations also support the space-based Aura-MLS observations, concluding that ASM anticyclone effectively transports ozone from the mid-latitude stratosphere to deep tropics. Shear generated turbulence and mixing in the vicinity of easterly jet also likely to play a minor role in the local ozone distribution.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Global climate is a multi-scale system whose subsystems interact complexly. Notably, the Tropical-Andean region has a strong rainfall variability because of the confluence of many global climate processes altered by morphological features. An approach for a synthetical climate description is the use of global indicators and their regional teleconnections. However, typically this is carried out using filters and correlations, which results in seasonal and inter-annual teleconnections information, which are difficult to integrate into a modeling framework. A new methodology, based on rainfall signal extraction using dynamic-harmonic-regressions (DHR) and stochastic-multiple-linear-regressions (SMLR) between rainfall components and global signals for searching intra-annual and inter-annual teleconnections, is proposed. DHR gives non-stationary inter-annual trends and intra-annual quasi-periodic oscillations for monthly rainfall measurements. Time-variable amplitudes of quasi-periodical oscillations are crucial for finding intra-annual teleconnections using SMLR, while trends are better suited for the case of inter-annual ones. The methodology is tested over a Tropical-Andean region in southern Ecuador. The following results were obtained: (1) trans-Niño-Index (TNI) and Tropical-South-Atlantic signals are strongly connected to inter-annual and intra-annual time-scales. (2) However, TNI progressively weakens its relation with intra-annual components; meanwhile, El-Niño-Southern-Oscillation 3 gains ground for such time-scales. (3) Finally, an inter-annual connection with the North-Atlantic-Oscillation (NAO) is revealed. These results are consistent with previous literature, although the TNI and NAO connections are interesting findings, taking into account the differences in the connected scales. These results show the methodology’s capability of unraveling global teleconnections in different space and time scales using attributes embedded in an integral mathematical framework, which could be interesting for other purposes—such as the analysis of climate mechanisms or climate modeling.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Decadal changes in the teleconnection between the central tropical Pacific and the Southern Hemisphere extratropics are studied using the NCEP–NCAR reanalysis data. Concurrent and lagged relationships show that teleconnection strength in austral spring was weak (strong) before (after) 1996/1997. This decadal change coincides in time with the climate regime shift in the Pacific in the 1990s known from many studies. We show that, after the regime shift, the concurrent and delayed teleconnection with the Southern Hemisphere extratropics is insignificant in September and abruptly increases in October. Penetration of the stratospheric anomaly into the troposphere in October can indicate interacting tropospheric and stratospheric pathways of the teleconnection to strongly enhance the central tropical Pacific impact since the late 1990s. The results give evidence that the Southern Annular Mode seems to be connecting element between the two pathways in the recent decades. The common tendencies in the eastward shift of the tropical anomalies and zonal wave 1 phase in the Antarctic stratosphere in austral spring have been demonstrated. The difference between the central Pacific and eastern Pacific teleconnections is consistent with that known from previous studies and new tendencies in their decadal changes and delayed effects have been revealed. It has been found that the central Pacific contributions to the Pacific decadal oscillation and to the Northern Hemisphere stratosphere have also increased significantly after the 1990s. This characterizes the central tropical Pacific as one of the key regions impacting climate and teleconnection not only in the Southern Hemisphere, but also in the Northern Hemisphere. Our findings are consistent with and further develop the recent studies of the stratosphere–troposphere coupling in austral spring, and emphasize significant contribution of the delayed tropical signals to the climate variability in austral spring in both hemispheres.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A simple theoretical model is constructed to understand the cause of a peculiar cooling trend in North Pacific under the background of the greenhouse gases induced global warming during the past 50 years. It is found that the North Pacific cooling is caused by the increase of surface upward latent heat flux due to the atmosphere and the decrease of surface downward shortwave radiative flux. The former is attributed to enhanced low-level westerlies, while the latter is caused by the increase of stratus cloud over North Pacific. An atmosphere general circulation model is utilized to investigate the cause of the wind and low-level cloud changes. It is found that the strengthened westerly in North Pacific is the result of an atmospheric teleconnection pattern forced by the SSTAs warming in the tropical Pacific. The SSTAs warming in other tropical basins, along with the local cooling in North Pacific, tends to reduce the tropical Pacific SSTAs forcing effect. In addition, the increased local low-level cloud response to the tropical Pacific SSTAs forcing is also responsible for the cooling trend in North Pacific. The increased local stratus cloud may enhance the cooling through a positive feedback among the SST, atmospheric static stability and stratus cloud.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sitapur district in the Uttar Pradesh (U.P.) state of northern India has been observed to consume large amounts of WHO classified “extremely” and “highly hazardous” pesticides, in rice crop, posing significant health and environmental threats. Keeping in view this problem, integrated pest management (IPM) modules were synthesized for rice crop and then compared with non-IPM/farmer’s practice (NIPM). This study assisted in identifying pesticides with reduced risk to the environment. To measure and compare risks, environmental impact quotient (EIQ) has been used as a pesticide risk indicator model, between IPM and NIPM programs. Using this model, the field EIQ values (EIQ field use rating or EIQ-FUR), for 32 commonly used pesticides in the region, were evaluated based on dosage, frequency, and percent active ingredients present in the pesticide formulations. The results conclude that copper oxychloride (CuOCl〈sub〉2〈/sub〉) (50 WP at 1.25 kg/ha) and mancozeb (75 WP at 1.25 kg/ha) were the most detrimental to arthropod parasitoids and were the highest contributors to environmental risk (13–16%), in rice crop. This is based on the comparison of total dosage and active ingredients of pesticides applied under IPM and NIPM, with the total field EIQ values. The IPM modules were observed to have least impact on natural enemies with 30–40% increase in population, while keeping the weed population below 10%. NIPM, on the other hand, had resulted in 20% reduction in crop yields, 50% reduction in biodiversity, and about 150% increase in weed population, relative to the control (untreated) rice fields. Moreover, NIPM practices had been observed to pose 56% greater risk as per the total field EIQ values (62 for IPM and 141 for NIPM). The observations concluded that the EIQ model is a useful tool and can be easily used by the pesticide managers for assessing the risk against NIPM.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The present study was aimed to examine the concentration of heavy metals in the two edible fish species 〈em〉Carassius carassius〈/em〉 and 〈em〉Triplophysa kashmirensis〈/em〉 of the Dal Lake (Srinagar, Jammu, and Kashmir, India). Metals cadmium (Cd), manganese (Mn), copper (Cu), zinc (Zn), lead (Pb), and chromium (Cr) were analyzed using atomic absorption spectroscopy (AAS). Differences in the heavy metal accumulation were observed between the two species as well as between different sizes of the same species. Small size fishes exhibited more concentration of heavy metals than the larger size fishes of the same species. Heavy metals were found in the ranking order of Zn 〉 Cr 〉 Pb 〉 Cu 〉 Mn 〉 Cd in both species of fishes and in both sizes as well. Zn, being the most concentrated metal found in both species, can pose a threat in the near future. Since both species are edible and constitute an essential part of human diet, the heavy metals assessed can be bioaccumulated in humans when consumed; hence, an extensive investigation is needed to evaluate the heavy metal concentration of other edible fishes of the Dal Lake in the future. The study will also be helpful in providing baseline data on the heavy metal accumulation of edible fish species in freshwater ecosystems.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Atmospheric visibility (AV) is an indicator for assessing air quality and is measured in standard weather stations. The AV can change as a result of two main factors: air pollution and atmospheric humidity. This study aimed to investigate trends in the number of days with AV equal or less than 2 km (D〈sub〉AV2〈/sub〉) in Iran during 1968–2013. Consequently, 43 weather stations with different climates were evaluated across the country, using the Mann–Kendall (MK) trend test. The results show that the number of stations with positive (i.e., significant or non-significant) MK 〈em〉z〈/em〉 values was equal to, or greater than, those with negative MK 〈em〉z〈/em〉 values, in all months and seasons of the year, as well as annually. Furthermore, summer and autumn had, respectively, the least and most stations with positive MK 〈em〉z〈/em〉 values. Fewer trends in D〈sub〉AV2〈/sub〉 were detected in the central, east, and northeast regions of the country. Analyzing the D〈sub〉AV2〈/sub〉 and relative humidity together indicated that over 30% of stations had at-risk air quality in January, and that the largest number of stations with at-risk air quality was in the autumn and winter. These results are useful for better environmental planning to improve air quality, especially in developing countries such as Iran, where reduced air quality has been a major problem in recent decades.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Estuaries are dynamic transition zones linking freshwater and oceanic habitats. These productive ecosystems are threatened by a variety of stressors including human modification of coastal watersheds. In this study, we examined potential linkages between estuarine condition and the watershed using multimodel inference. We examined attributes at the watershed scale as well as those associated with riparian areas but found that they were highly correlated. We also examined whether attributes closer to the estuary were more strongly related to benthic invertebrate condition and found that this was not generally true. In contrast, variability within the estuary strongly impacted model results and suggests that future modeling should incorporate estuarine variability or focus on the individual stations within the estuary. Modeling estuarine condition indicated that inherent landscape structure (e.g., estuarine area, watershed area, watershed:estuary ratio) is important to predicting benthic invertebrate condition and needs to be considered in the context of watershed/ estuary planning and restoration.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A highly sensitive colorimetric assay is described for the determination of glutathione (GSH). It is based on the use of tungsten disulfide (WS〈sub〉2〈/sub〉) which is a peroxidase mimic. It catalyzes the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by hydrogen peroxide to form a blue-colored product (oxTMB) at near neutral pH values. In the presence of the analyte GSH, it is transformed to its oxidized form (GSSG), while the blue oxTMB is increasingly reduced and eventually is converted to colorless TMB. This can readily be detected with bare eyes. GSH can be determined spectroscopically (at 652 nm) by this method at concentrations down to 61 pM, and the response is linear in the 100 pM to 10 nM GSH concentration range. The assay is cost-effective and simple. Conceivably, it provides a promising tool for the determination of GSH in food and medical samples.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schemaric of a sensitive method for colorimetric detection of glutathione (GSH) based on WS〈sub〉2〈/sub〉-catalyzed oxidation of TMB by H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 and the reduction of blue oxTMB by GSH.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3365_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Glyphosate (GLP, 〈em〉N〈/em〉-(phosphonomethyl)glycine) is the most important broadband herbicide in the world, but discussions are controversial regarding its environmental behaviour and distribution. Residue analyses in a variety of environmental samples are commonly conducted by HPLC–MS where GLP needs to be derivatised with 9-fluoromethoxycarnonyl chloride (FMOC-Cl). Since this derivatisation reaction was suspected to be inhibited by metal ions in the sample matrix, the present study provides a comprehensive experimental study of the effect of metal ions (Al〈sup〉3+〈/sup〉, Ca〈sup〉2+〈/sup〉, Cd〈sup〉2+〈/sup〉, Co〈sup〉2+〈/sup〉, Cu〈sup〉2+〈/sup〉, Fe〈sup〉2+〈/sup〉, Fe〈sup〉3+〈/sup〉, Mg〈sup〉2+〈/sup〉, Mn〈sup〉2+〈/sup〉, Zn〈sup〉2+〈/sup〉) on derivatisation and GLP recovery. Results show that some metals (Cd〈sup〉2+〈/sup〉, Co〈sup〉2+〈/sup〉, Cu〈sup〉2+〈/sup〉, Mn〈sup〉2+〈/sup〉 and Zn〈sup〉2+〈/sup〉) decreased the GLP recovery down to 19 to 59%. Complementary, quantum chemical modelling of 1:1 GLP–metal complexes as well as their reactivity with respect to FMOC-Cl was performed. Here, a decrease in reactivity of FMOC-Cl towards GLP–metal complexes is observed; i.e. the reaction is non-spontaneous in contrast to the free GLP case. The present results are in accord with previous studies and provide an explanation that full GLP recovery in different matrices was never reached. Remedy strategies to compensate for the inhibition effect are explored such as pH adjustment to acidic or alkaline conditions or addition of ethylenediaminetetraacetic acid (EDTA). In general, our results question the use of internal isotopic labelled standards (ILS) since this presupposes the presence of the analyte and the ILS in the same (free) form.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The effect of cumulus parameterization (CP) on simulated climatological tropical cyclone (TC) activity over the CORDEX East Asia domain has been investigated by using the weather research and forecasting model. The simulations were conducted during 1988–2009 with a 25-km horizontal resolution, driven by the ERA-Interim reanalysis. Five experiments were performed and evaluated with different CP schemes including Kain–Fritsch (KF), KF with modified convective trigger function (KFML), multi-scale KF (MsKF), simplified Arakawa–Schubert (SAS) and Betts–Miller–Janjic (BMJ) schemes. Significant differences of TC genesis locations and tracks can be found between the CP schemes, which are attributed to simulated large-scale environment discrepancies. Simulations with the KF, KFML and MsKF schemes produced more TC numbers and stronger intensities than the SAS and BMJ simulations. The eastward extension and enhancement of the monsoon trough (MT) in the KF, KFML and MsKF simulations caused a southeast shift of the main TC genesis region, and provided a suitable environment for TC development. The KFML simulation reduced the excessive rainfall and TC activities that had appeared in the KF simulation and increased the proportion of intense TCs. The reduced tropical surface latent and moisture flux in the MsKF simulation, along with weaker upward vertical motion, contributed to weaker tropical rainfall and TC intensities. The SAS simulation produced less large-scale instabilities, which led to less active convections and weaker TC genesis and intensities. The genesis region in the BMJ simulation was shifted further north due to the northward-shifted reverse-oriented MT together with enhanced wind shear over the tropical ocean, resulting in detrimental environmental conditions for TC development. In addition, the BMJ scheme produced significant upper-tropospheric warming, attributed to enhanced grid-scale convective heat transport and latent heating of condensation in high-level stratiform cloud extending to the south boundary of WPSH, this resulted in the retreat of the subtropical high and caused the TC to recurve earlier.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Extracting annual cycle properly from climate series is important in the study of annual cycle and anomaly series. However, the extracting approaches are various and may lead to inconsistent results. Since the real annual cycle is unknown in observed records, the reliability and applicability of them are hard to estimate. In this study, five popular decomposition methods used to extract annual cycle in climate series are evaluated through idealized numerical experiments for the first time; i.e., fitting sinusoids, complex demodulation, ensemble empirical mode decomposition (EEMD), nonlinear mode decomposition (NMD) and seasonal trend decomposition procedure based on loess (STL). Their performances are examined by comparing the extracted annual cycles and its amplitude with the preset one. The annual cycles are set with three different changing amplitudes: constant, linear increasing and nonlinearly varying; superposed with fluctuations of different long-term persistence (LTP) strength. Results indicate that (1) NMD performs best in depicting annual cycle and obtaining its amplitude change; (2) fitting sinusoids, complex demodulation and EEMD methods are more sensitive to LTP strength of superimposed fluctuations, which leads to over-fitted annual cycles and noisy amplitude changes, oppositely, the STL are less responsive to the variation of annual cycle; (3) when overall long-time trend of annual cycle change is the main concern, all of these methods performed well. However, over short time scales, the errors on account of noise and LTP are common in the first three methods and STL is too rough to give the details of amplitude change. Those results are also verified by applying them to observed records and the case with both amplitude and phase change.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A statistical downscaling method (SDM) has been established through multiple stepwise regressions of predictor principal components using the ERA-Interim reanalysis data and the meteorological data collected from 115 stations in the low-latitude plateau in China from 1981 to 2015. The skill of the SDM was checked by comparing the results of the different predictor combinations and the different time lengths used to construct the SDM. In addition, compared to the historical simulation of the coupled Max Planck Institute Earth System Model (MPI-ESM-LR), better performance can be achieved by using the ERA-Interim data to construct the SDM in the low-latitude plateau. The long-term changes in temperature from 1981 to 2015 in the ERA-Interim reanalysis data are calibrated by the SDM over the low-latitude plateau of China. Furthermore, the SDM is projected into the simulation results of the MPI-ESM-LR model to construct a suitable SDM (ERA-SDM), and then the ERA-SDM is implemented to evaluate the future temperature changes in the low-latitude plateau during the period of 2018–2100 using the simulation results of the MPI-ESM-LR model under the RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. The results showed that an increase in temperature of 0.3 °C decade〈sup〉−1〈/sup〉 was found from 1981 to 2015, in which the fastest increase of 0.4 °C decade〈sup〉−1〈/sup〉 occurred in winter and the slowest increase of 0.2 °C decade〈sup〉−1〈/sup〉 occurred in autumn. Most models in CMIP5 failed to simulate the long-term changes in temperature over the last 30 years in the low-latitude plateau region, and the temperature in the low-latitude plateau was underestimated by 2.4 °C using the 22 models. The SDM improved the annual and seasonal temperature characteristics and inter-annual and seasonal changes simulated by the MPI-ESM-LR. The future temperature predictions by the ERA-SDM indicated that the fastest temperature increase of 0.271 °C decade〈sup〉−1〈/sup〉 was found in spring under the RCP8.5 scenario. A faster rate of temperature increase was found in the northern part of the low-latitude plateau than in the southern part under the RCP8.5 scenario.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A first systematic analysis was conducted to assess near-term future changes in climate extremes over East Asia during the summer season (June–August) using five regional climate model (RCM) simulations participating in the CORDEX-East Asia project (HadGEM3-RA, RegCM4, SNU-MM5, SNU-WRF, and YSU-RSM). The 20-year return values of extreme temperature and precipitation were compared between the present (1979–2005) and near-term future (2024–2049) periods, which were estimated using the generalized extreme value (GEV) analysis. Multi-RCM mean results show that temperature and precipitation will increase in both means and extremes and that the increase in precipitation extreme will follow the enhanced moisture availability with warming (~ 7% °C〈sup〉−1〈/sup〉, Clausius–Clapeyron relation). It was found that the increases in GEV location parameter (mean intensity) and scale parameter (inter-annual variability) contribute dominantly to the increase in extremes of temperature and precipitation, respectively. Robust inter-RCM relations were observed between mean and extreme projections over East Asia and even on grid scales, more strongly for temperature. Model biases and future projections exhibit a significant relationship for temperature such that RCMs with warmer biases tend to predict stronger warming and vice versa. Results from three sub-regions (South Korea, Southern China, and Mongolia and northern China) consistently indicate that temperature increase involves an overall shift of the daily temperature distribution toward warmer conditions while precipitation increases are due to dominant increases in moderate-heavy rainfall events. Our multi-RCM assessment provides new insights to the uncertainty in future climate extremes over East Asia.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The secular change of the Asian monsoon (AM)-El Niño–Southern Oscillation (ENSO) relationship has been recognized as a specter for seasonal forecast. The causes of such changes have not been well understood. How the monsoon-ENSO relationship underwent secular changes beyond instrumental period has rarely been discussed. Here we explore the multidecadal to centennial changes of the AM-ENSO relationship with the recently compiled Reconstructed Asian summer Precipitation (RAP) dataset (1470–2013) and multiple ENSO proxy indices. During the past five centuries, two leading modes of interannual variability of RAP are found to be associated with the ENSO developing and decaying phases, respectively. The mechanisms behind the modern monsoon-ENSO relationship can reasonably well explain the past monsoon behavior. In response to a developing ENSO, precipitation anomalies from the Maritime Continent (MC) via India to northern China are in phase, and this “chain reaction” tends to be largely steady since around 1620 AD when the Indian summer monsoon abruptly strengthened. Further, the strengthening of the link between developing-ENSO and Indian-northern China rainfall since 1620 AD concurred with a phase reversal of the Pacific Decadal Oscillation. During the decaying phase, however, the summer rainfall-ENSO relationship over the Yangtze River Valley-southern East China (YRV-SEC), the MC and central Asia, has gone through large multidecadal to centennial changes over the past five centuries. A remarkable reversal of sign in the AM-decaying ENSO relationship occurred roughly from 1740 to 1760 over the YRV-SEC and MC, which may be associated with the long-term strengthening of ENSO intensity. Future research should continue focusing on revealing the possible causes of the low-frequency changes in the monsoon-ENSO relationship using general circulation models and paleoclimate proxy reconstructions.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Groundwater resources are facing a high pressure due to drought and overexploitation. The main aim of this research is to apply rotation forest (RTF) with decision trees as base classifiers and an improved ensemble methodology based on evidential belief function and tree-based models (EBFTM) for preparing groundwater potential maps (GPM). The performance of these new models is then compared with three previously implemented models, i.e., boosted regression tree (BRT), classification and regression tree (CART), and random forest (RF). For this purpose, spring locations in the Meshgin Shahr in Iran were detected. The spring locations were randomly categorized into training (70% of the locations) and validation (30% of the locations) datasets. Furthermore, several groundwater conditioning factors (GCFs) such as hydrogeological, topographical, and land use factors were mapped and regarded as input variables. The tree-based algorithms (i.e., BRT, CART, RF, and RTF) were applied by implementing the input variables and training dataset. The groundwater potential values (i.e., spring occurrence probability) obtained by the BRT, CART, RF, and RTF models for all the pixels of the study area were classified into four potential classes and then used as inputs of the EBF model to construct the new ensemble model (i.e., EBFTM). At last, this paper implemented a receiver operating characteristics (ROC) curve for determining the efficiency of the EBFTM, RTF, BRT, CART, and RF methods. The findings illustrated that the EBFTM had the highest efficacy with an area under the ROC curve (AUC) of 90.4%, followed by the RF, BRT, CART, and RTF models with AUC-ROC values of 90.1, 89.8, 86.9, and 86.2%, respectively. Thus, it could be inferred that the ensemble approach is capable of improving the efficacy of the single tree-based models in GPM production.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The technology for remediating heavy metal–contaminated soil is considerably limited because heavy metals do not undergo decomposition. Off-site reuse has emerged as the main technique for treating heavy metal–contaminated soil. Soil is the primary material in red brick making; and in the sintering procedure, heavy metals could solidify and stabilize within bricks. In this study, lead-, nickel-, and chromium-contaminated soils were collected from multiple agricultural fields. The sintering process was performed using a kiln that was for making red bricks. The sintering temperature was approximately 1000 °C. Soil and brick samples, before and after sintering, were analyzed for metal extraction concentration and binding form distribution. After sintering, the concentrations of Pb, Ni, and Cr determined through X-ray fluorescence approximated the concentrations in the soil. However, in the bricks, the bioavailability concentration of Pb, Ni, and Cr is less than 1% of that in the soil; the toxicity characteristic leaching procedure (TCLP) leaching concentration of Pb in the bricks was only 4% of that in the soil, and the leaching concentrations of Ni and Cr were lower than the detectable concentration. For the aqua regia extraction method, in the bricks, the Pb, Ni, and Cr were extracted and the concentrations accounted for 4.6%, 8.8%, and 9.4% of the concentrations in the soil, respectively. After sintering, more than 95% of Ni and Cr in the bricks were in residual fractions. The sintering process has the ability to stabilize the heavy metals in the contaminated soil.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A fluorometric method was developed for the determination of the insecticide cartap. It is based on the use of green emitting carbon dots (CDs) and gold nanoparticles (Au NPs). The CDs were prepared from phenol and ethylene diamine by a hydrothermal route. They have excitation/emission maxima at 410/513 nm) and a fluorescence quantum yield of 29%. They were characterized by TEM, Raman, XRD, XPS, FT-IR, UV and fluorescence spectroscopies. The green fluorescence of the CDs is strongly reduced by the red-colored Au NPs because of an inner filter effect. Upon addition of cartap, it will cause the aggregation of the Au NPs owing to Au-N interaction between Au NPs and cartap to form purple colored aggregates with spectra that do not overlap the green emission of the CDs. Hence, their fluorescence is restored. Under optimum conditions, the method allows for the quantitation of cartap in the 5–300 nM concentration range, and the detection limit is 3.8 nM. The method was successfully applied to the determination of cartap in spiked real samples and gave satisfactory results.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of green emitting carbon dots for sensitive fluorometric determination of cartap based on its aggregation effect on gold nanoparticles.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3361_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The present study investigated the effect of contact time, the initial concentration of metal ions, and the biomass dose on the Cu(II) biosorption from an aqueous solution using dead biomass of filamentous fungus 〈em〉Penicillium ochrochloron〈/em〉, which was isolated at the Sossego mine, a copper-contaminated site located in Canaã dos Carajás city, Brazil. The Cu(II) biosorption started rapidly and increased gradually until the equilibrium was reached at 20 min. The Cu(II) uptake decreased as the initial Cu(II) concentration increased, reaching the saturation at 200 mg/L. The Cu(II) biosorption was considerably higher using 0.2 g than 0.5 g of the biomass in 50 mL of solution. The average biosorption capacity of Cu(II) was 7.53 mg/g and the maximum Cu(II) removal 75.0%. The Freundlich and Langmuir isotherm models adequately described the adsorption data. Our results evidenced that the dead biomass of 〈em〉P. ochrochloron〈/em〉 has a great potential as a biosorbent to remove copper from an aqueous solution. Therefore, it could be explored for the development of the environmental recovery process.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Palestine, being a developing country, faces lots of obstacles and deficiencies in the existing solid waste management (SWM) field. In wake of these circumstances, it seems hard for the public sector to run sustainable SWM systems. The overall objective of the research presented in this paper was to study the current status of the SWM field in the West Bank of Palestine under the perspective of potential private sector involvement. For this purpose, twelve Joint Service Councils (JSCs) for solid waste management were investigated. Out of them, only two are currently having a Public–Private Partnership (PPP) contract for the management and operation of the transfer station and the sanitary landfill. On the other hand, two JSCs are currently making arrangements and implementing studies for future PPPs on waste-to-energy, biowaste management and recycling projects. Jenin and Tubas Joint Service Council (JSC) had 3-month-duration PPP contract for the implementation of a recycling project, which is a worst case scenario as it failed to meet its objectives. The parameters that could encourage JSCs or ease the implementation of PPP in local SWM field are analysed. Overall conclusion is that sustainability can be accelerated once the government—represented by the Ministry of Local Government (MoLG)—is involved; providing legal support to local authorities and incentives to potential contractors in order to encourage them to join PPPs. Parameters that are believed to facilitate PPPs include the following: development or updating existing laws and regulations, facilitation of licensing procedures, and activation of the Investment Promotion Law. Feasibility and market analysis study implementation will indicate the appropriate actions required locally to achieve environmental and financial sustainability in all contracted PPPs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Global surface evapotranspiration is one of the most significant components of the response of the water cycle to a warming climate. However, trends in surface evapotranspiration differ considerably from the trend in climate warming according to recent studies, with some studies even showing an opposing trend. The reason for this difference in the response of surface evapotranspiration to climate warming is still not completely understood. We validated the gridded FLUXNET evapotranspiration dataset and the Global Land Surface Assimilation Dataset (GLDAS) against evapotranspiration data observed in northern China using the eddy covariance system. The response of surface evapotranspiration to an increase in temperature varied with the type of climate (classified by the amount of precipitation) and the trend of surface evapotranspiration with warming showed similar features to the transitions between these climate types. The climate type with precipitation in the range of 250–350 mm was the most sensitive to the effects of warming on evapotranspiration. In more humid climates, surface evapotranspiration increased with increasing temperature, whereas in drier climates surface evapotranspiration decreased with increasing temperature. A similar response of evapotranspiration to increasing temperatures was also observed elsewhere in regions of climate transition. There are two main mechanisms of evapotranspiration: (1) an increase in temperature resulting in a direct increase in potential evapotranspiration; and (2) an increase in temperature resulting in a loss of soil moisture due to the increase in evapotranspiration, which in turn will indirectly suppress surface evapotranspiration due to the loss of vegetation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The rectification of intraseasonal wind forcing on interannual sea surface temperature anomalies (SSTA) and sea level anomalies (SLA) associated with El Niño–Southern Oscillation (ENSO) during 1993–2016 are investigated using the LICOM ocean general circulation model forced with daily winds. The comparisons of the experiments with and without the intraseasonal wind forcing have shown that the rectified interannual SSTA and SLA by the intraseasonal winds are much weaker than the total interannual SSTA and SLA in the cold tongue, due to the much weaker rectified than the total interannual Kelvin and Rossby waves in the equatorial Pacific Ocean. The dynamics of the rectification are through the nonlinear zonal and vertical advection by the background currents, which produces downwelling equatorial Kelvin waves during El Niño. The meridional advection is much smaller than the zonal and vertical advection, suggesting that the rectification is not induced by the Ekman dynamics or the thermocline rectification. The rectified interannual Kelvin waves are found to be much smaller than reflected at the Pacific western boundary and those forced by the interannual winds, suggesting that the latter two play a much more important role in ENSO dynamics than the intraseasonal winds. The results of this study suggest an unlikely significant role of oceanic nonlinear rectification by intraseasonal winds during the onset and cycling of El Niño.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Future hydroclimate change is expected to generally follow a wet-get-wetter, dry-get-drier (WWDD) pattern, yet key uncertainties remain regionally and over land. It has been previously hypothesized that lake levels of the Last Glacial Maximum (LGM) could map a reverse analog to future hydroclimate changes due to reduction of CO〈sub〉2〈/sub〉 levels at this time. Potential complications to this approach include, however, the confounding effects of factors such as the Laurentide Ice Sheet and lake evaporation changes. Using the ensemble output of six coupled climate models, lake energy and water balance models, an atmospheric moisture budget analysis, and additional CO〈sub〉2〈/sub〉 sensitivity experiments, we assess the effectiveness of the LGM as a reverse analog for future hydroclimate changes for a transect from the drylands of North America to southern South America. The model ensemble successfully simulates the general pattern of lower tropical lake levels and higher extratropical lake levels at LGM, matching 82% of the lake proxy records. The greatest model-data mismatch occurs in tropical and extratropical South America, potentially as a result of underestimated changes in temperature and surface evaporation. Thermodynamic processes of the mean circulation best explain the direction of lake changes observed in the proxy record, particularly in the tropics and Pacific coasts of the extratropics, and produce a WWDD pattern. CO〈sub〉2〈/sub〉 forcing alone cannot account for LGM lake level changes, however, as the enhanced cooling from the Laurentide ice sheet appears necessary to generate LGM dry anomalies in the tropics and to deepen anomalies in the extratropics. LGM performance as a reverse analog is regionally dependent as anti-correlation between LGM and future P − E is not uniformly observed across the study domain.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Short-term concurrent droughts and heatwaves accompanied by high temperatures and low soil moisture (or low precipitation) may significantly impact ecosystems, societies, and economies although the individual events involved may not themselves represent severe extremes. There is little known about the potential frequency of short-term concurrent droughts and heatwaves in the future. Here, we use the Gan River Basin as a case study area to assess the effects of different warming levels on drought and heatwave concurrences based on the coupled model intercomparison project phase 5 and variable infiltration capacity (VIC) model. The results show that the VIC model has high reliability in the simulation of soil moisture and evapotranspiration compared with other well-recognized datasets in the Gan River Basin. The warming level over the Gan River Basin is close to the global warming level. Under RCP4.5 and RCP8.5 scenarios, the multi-model ensemble medians of concurrent events increased by 0.08–0.4 pentads/decade from 2006 to 2099. The uncertainty of concurrent events encompasses a wider range as global temperature increases. Compared to the reference period (1961–2005), drought and heatwave concurrences have increased by more than 50% in the most parts of the basin under 1.5 or 2.0 °C of global warming; there is a 20% frequency difference of 0.5 °C from 1.5 to 2.0 °C. The substantial pentad increases (at least greater than 50%) existed in historical low-pentad-value areas in a 1.5 or 2.0 °C world, especially pronounced for a 2.0 °C world. The greatest increase in concurrent event pentads came from the 25th percentile values in 1.5 or 2.0 °C scenarios. Climatological median pentads of concurrent droughts and heatwaves appear likely to be 9.6–17.6% more frequent in a 2.0 °C world than a 1.5 °C world with respect to the reference period.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Winter-to-early spring non-monsoonal precipitation over the Western Himalayas (WH) primarily comes from eastward propagating synoptic-scale weather systems known as western disturbances (WDs). Earlier studies have noted that an increasing trend of synoptic-scale WD activity in the past few decades has contributed to enhanced propensity of daily precipitation extremes over the WH, although it remains unclear as to whether these regional changes are manifestations of climate change. This issue is addressed by conducting a suite of long-term climate experiments using a global variable-grid climate model with high-resolution telescopic zooming over the South Asian region. Our findings highlight that human-induced climate change has implications on the rising trend of synoptic-scale WD activity and precipitation extremes over the WH during the recent few decades, and these changes cannot be explained by natural forcing alone. A stronger surface warming, in response to climate change, is noted over the vast expanse of the high-elevated eastern Tibetan Plateau relative to the western side. The model simulations show that strengthening of positive east–west temperature gradient across the Tibetan Plateau tends to alter the background mean circulation in a manner as to favor amplitude enhancements of the synoptic-scale WDs and orographic precipitation over the WH. With continuation of global warming in future and enhancement in the east–west temperature gradient across the Tibetan highlands, the trend of precipitation extremes over the WH and synoptic-scale WD activity are projected to rise into the twenty-first century. While the high-resolution simulations of this study offers promising potential to understand changes in synoptic-scale WD activity and precipitation extremes over the WH, further investigations are necessary to decipher the multi-scale behavior and intricacies of the Himalayan precipitation variability under changing climate.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Despite the monotonically rising greenhouse gas emission, global warming rate changes again and again, especially the slowdown during 1998–2013, challenging the current global temperature change mechanisms. Recently, different-scale natural climate variabilities have been individually recognized as the potential causes of global warming rate change, particularly the recent warming slowdown, but disagreements still exist on their relative importance. Here we quantify the contribution of interannual, interdecadal and multidecadal variabilities (IAV, IDV and MDV) in modulating the global warming rate during the period 1850–2017 via decomposing the global mean temperature timeseries derived from 12 datasets into several quasi-periodic fluctuations and a monotonical secular trend (ST) using the ensemble empirical mode decomposition method. Our results show that the IAV, IDV and MDV dominate the global warming rate change together, rather than one-scale variability alone. For example, during 1998–2013 both the IAV and IDV present obvious negative trends and combine to cut 59 ± 22% of global mean surface temperature (GMST) and 65 ± 38% of sea surface temperature (SST) positive trends which are caused by the steadily warming ST and the warming phase of MDV, thus causing an apparent warming slowdown during this period. Furthermore, we illustrate that the IAV, IDV and MDV mainly originate from the El Niño-Southern oscillation (ENSO), Pacific decadal oscillation (PDO) and Atlantic multidecadal oscillation (AMO), respectively. Our work partly reconciles the controversy over the importance of different-scale natural variabilities, and provides some insights for climate change attribution and prediction research.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In the present work, the mechanisms for the changes in moisture sources (evaporation minus precipitation; EmP) during boreal summer (May–September) are explored over the tropical Indian Ocean during 1979–2016. We apply a moisture budget analysis to quantify the thermodynamic and dynamic effects. Our results show that the EmP in the tropical central-eastern and southwestern Indian Oceans experienced significant increasing trends during boreal summer. The increased EmP in the tropical central-eastern Indian Ocean is due to the enhanced dynamic divergence (account for approximately 51%), while a stronger dynamic advection contributes more moisture supply to the southwestern Indian Ocean (account for approximately 34%). We find that during recent decades, the enhanced east–west thermal gradient in the Pacific strengthens the Walker Circulation, which leads to a westward shift in convection over the Indian Ocean warm pool, resulting in weakened convection and ascent over the tropical central-eastern Indian Ocean. The weakened convection leads to an anomalous low-level atmospheric divergent circulation, which intensifies the dynamic divergence contributing to the enhanced EmP over the tropical central-eastern Indian Ocean. Additionally, the warming climate during recent decades also increases the land–sea thermal contrast in the vicinity of the Indian Ocean, which enhances the southeastern wind in the low-level troposphere and leads to an enhanced EmP over the southwestern Indian Ocean.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The great rivers that flow from the southern Tibetan Plateau (TP) affect billions of people in the downstream countries of Asia. Understanding of the hydrological variability of these rivers is still limited, however, because of the lack of long-term streamflow records. Tree-ring width chronologies from six sites are applied to reconstruct annual streamflow of the Salween River, the last remaining large free-flowing transboundary river draining the southern TP, and a critical water source for countries of Southeast Asia. Response function analysis shows that precipitation is the main factor limiting the radial growth of the sampled trees. Linear regression of annual (September–June) Salween River streamflow on the first principal component of tree-ring chronologies explains 53.4% of the streamflow variance, 1958–2011, and yields a reconstruction for the interval 1500–2011 CE. A tally of droughts and wet periods emphasizes the severity of droughts before the start of the gauged records, and a tendency toward wetter conditions in recent decades. Regional temperature is negatively associated with the reconstructed streamflow. Cold wet summers controlled by the Asian summer monsoon are responsible for an increasing trend in streamflow over the last decades. Reconstructed hydrological change is linked to the history of mainland Southeast Asia through the impact of water shortages on Burma society. In particular, prolonged periods of low flow of the Salween River coincide with the falls of the Toungoo Empires and the First Anglo-Burmese War. This tree-ring reconstruction provides a long-term perspective on hydrological changes in the Upper Salween River Basin that can give insight for sustainable water management on the TP and in Myanmar.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The exorable climate changes leads to changes in the frequency and intensity of extreme rainfall events worldwide; however, the amendment in extreme rainfall events is not uniform over space, precisely it is more localized and a great threat to the society. Thus, study of rainfall extremes at a finer spatial scale is essential and identifying the large-scale parameters that are responsible factors is highly needed. Odisha state in India is one of the most vulnerable to weather extremes and considered as a study region. The present study is bi-fold, firstly examining the changes in the extreme rainfall (≥ 204.5 mm/day) over Odisha and exploring the foremost large-scale meteorological parameters responsible for heterogeneous characteristics of extreme rainfall within Odisha during 1980–2017 summer monsoon period. India Meteorological Department gridded high-resolution (0.25° × 0.25°) rainfall analysis and ERA-Interim (0.25° × 0.25°) reanalysis data at daily scale are used for the analysis. The study region has an increasing trend in extreme rainfall events and it is evident that the Indian Ocean is warmer during extreme rainfall events compared to the dry events, particularly near the seashore of Odisha. The stronger (weak) and cyclonic (anti-cyclonic) flows at 850-hPa exhibit during extreme rainfall (dry) events. The moisture flux is convergent during extreme rainfall events, while it is reverse during dry events. The monsoon trough has been shifted to south (north) from its normal position during extreme rainfall (dry) events. A detailed investigation is carried out for extreme rainfall events over five different regions in Odisha. It reveals that the wind at 850 hPa, omega at 500 hPa, and SST play the important role for Region I, while OLR and omega at 500 hPa are dominating for the Region IV in the occurrence of extreme rainfall. Moreover, the role of the dominant climatic parameters for the extreme rainfall occurrence varies for the other three regions. Analysis confirms that the role of main meteorological parameters is statistically significant for the extreme rainfall events over the respective region. Although the Odisha is a small state in India, not only the long-term trend in extreme rainfall varies region-to-region but also responsible factors associated with the climatic conditions differ for the occurrence of the extreme rainfall.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉We analyze European temperature variability from station data with the method of detrended fluctuation analysis. This method is known to give a scaling exponent indicating long range correlations in time for temperature anomalies. However, by a more careful look at the fluctuation function we are able to explain the emergent scaling behaviour by short time relaxation, the yearly cycle and one additional process. It turns out that for many stations this interannual variability is an oscillatory mode with a period length of approximately 7–8 years, which is consistent with results of other methods. We discuss the spatial patterns in all parameters and validate the finding of the 7–8 year period by comparing stations with and without this mode.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study contrasts two types of quasi-biweekly oscillations (QBWOs) over tropical Asia in late-summer and autumn (from August to October). Using a tracking method to calculate the frequency of QBWO events over the Asian monsoon region, two types of QBWOs in monsoon rainfall are revealed. One originates from 110° to 140°E and propagates westward to southern China with a notable impact on the regional rainfall, while the other initiates from 160°E to the dateline and does not affect southern China rainfall significantly. Analysis of the vertical structure of moisture flux shows that the moisture source for type 1 events is dominated by the zonal flux component and that for type 2 the meridional flux component. The nature of the moisture flux determines whether the oscillation can propagate across 120°E and affect rainfall over southern China. Results also show that the strength of the South Asian high and the western Pacific subtropical high differently modulate the generation of the two types of QBWOs. Specifically, mutually stronger (weaker) highs favor the first (second) type of the oscillation. A close relationship also exists between the QBWOs and western Pacific sea surface temperature (SST) anomalies, suggesting that the SST anomalies can potentially trigger the QBWOs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The presence of thin sea ice is indicative of active freezing conditions in the polar ocean. We propose a simple yet effective method to incorporate information of thin-ice category into coupled ocean–sea-ice model simulations. In our approach, the thin-ice distribution restricts thick-ice extent and constrains atmosphere–ocean heat exchange through the sea ice. Our model simulation with the incorporation of satellite-derived thin-ice data for the Arctic Ocean showed much improved representation of sea-ice and upper-ocean fields, including sea-ice thickness in the Canadian Archipelago and the region north of Greenland, mixed-layer depth over the Central Arctic, and surface-layer salinity over the open ocean. Enhanced sea-ice production by the thin-ice data constraint increased the total sea-ice volume of the Arctic Ocean by 〈span〉 〈span〉\(5 \times 10^{3}\)〈/span〉 〈/span〉–〈span〉 〈span〉\(10 \times 10^{3}\)〈/span〉 〈/span〉 km〈sup〉3〈/sup〉. Subsequent sea-ice melting was also enhanced, leading to the greater amplitude of the seasonal cycle by approximately 〈span〉 〈span〉\(2 \times 10^{3}\)〈/span〉 〈/span〉 km〈sup〉3〈/sup〉 (15% of the baseline value from the experiment without the thin-ice data incorporation). Overall, our results demonstrate that the incorporation of satellite-derived information on thin sea ice has great potential for the improvement of coupled ocean–sea-ice simulations.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper surveys the current state of knowledge regarding large-scale meteorological patterns (LSMPs) associated with short-duration (less than 1 week) extreme precipitation events over North America. In contrast to teleconnections, which are typically defined based on the characteristic spatial variations of a meteorological field or on the remote circulation response to a known forcing, LSMPs are defined relative to the occurrence of a specific phenomenon—here, extreme precipitation—and with an emphasis on the synoptic scales that have a primary influence in individual events, have medium-range weather predictability, and are well-resolved in both weather and climate models. For the LSMP relationship with extreme precipitation, we consider the previous literature with respect to definitions and data, dynamical mechanisms, model representation, and climate change trends. There is considerable uncertainty in identifying extremes based on existing observational precipitation data and some limitations in analyzing the associated LSMPs in reanalysis data. Many different definitions of “extreme” are in use, making it difficult to directly compare different studies. Dynamically, several types of meteorological systems—extratropical cyclones, tropical cyclones, mesoscale convective systems, and mesohighs—and several mechanisms—fronts, atmospheric rivers, and orographic ascent—have been shown to be important aspects of extreme precipitation LSMPs. The extreme precipitation is often realized through mesoscale processes organized, enhanced, or triggered by the LSMP. Understanding of model representation, trends, and projections for LSMPs is at an early stage, although some promising analysis techniques have been identified and the LSMP perspective is useful for evaluating the model dynamics associated with extremes.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉As the most significant interannual variability in the climate system, El Niño-Southern Oscillation (ENSO) has critical effects on global weather and climate patterns. To simulate and predict ENSO, coupled general circulation models (CGCMs) have become a key tool. However, the accurate simulation of ENSO is still a challenge for CGCMs. The performance of El Niño simulations conducted through FIO-ESM v1.0 is examined based on the outputs of the Coupled Model Intercomparsion Project phase 5 (CMIP5) historical experiments. The results show that FIO-ESM v1.0 suffers from similar common problems to other CMIP5 models, including an eastward shift in the central locations of El Niño, adopting a regular period of roughly 3 years, addressing excessively high amplitude, spurious eastward propagation of El Niño events, and Aborted El Niño events. El Niño composite and mixed layer heat budget analyses indicate that these simulation biases are mainly associated with the mean state biases, including a warm Sea Surface Temperature (SST) bias for the central-eastern Pacific, a cold SST bias for the western and central Pacific, seasonal cycles of SST of the equatorial eastern Pacific, and weaker trade winds. Weaker SST-cloud-shortwave radiation feedback in La Niña events than in El Niño events is what creates spurious ENSO amplitude symmetry in the model. We suggest that the improvement of El Niño simulations may be realized by focusing on the mean state and SST-cloud-shortwave radiation feedback in the tropical region. Specifically, further incremental improvements in the mean state of the tropical Pacific should constitute the first step to realizing more accurate ENSO simulation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The precise influence of climate change on extratropical cyclone genesis and evolution is an important (but as yet unsolved) problem, given their physical and economic impact on a large portion of the planet’s population. However, extratropical cyclones are also affected by the competing influences of forcing mechanisms at a wide range of spatial scales, complicating the problem. While the advent of idealized numerical modeling has allowed great strides in addressing these complications and achieving some qualitative consensus in the literature, there is still some quantitative disagreement about response magnitude and where local maxima and minima in the response may be located. Thus, the advantages inherent in the variety of idealized numerical modeling methods used to address this problem are also a drawback, as it can be difficult to draw one-to-one comparisons across experiments. Although the effects of particular model architecture choices such as microphysical and cumulus schemes are well-documented, others are less understood. In this study, we examine the role of Coriolis approximations by comparing a new set of ETC sensitivity experiments using a linear 〈em〉 β〈/em〉-plane approximation to an existing set of extratropical sensitivity experiments using a constant 〈em〉f〈/em〉-plane approximation. ETCs within the new 〈em〉 β〈/em〉-plane experiment are found to generally decrease in strength with temperature, as measured by both minimum sea level pressure and maximum eddy kinetic energy (EKE). A small increase in EKE is observed at the warmest temperatures, likely due to diabatic influences disrupting flow within the warm conveyor belt. While seemingly contradictory to the previous 〈em〉f〈/em〉-plane results, the two experiments are instead found to be qualitatively similar upon further inspection, with an offset of approximately 8 K. This offset is primarily due to the Coriolis approximations, although the initial stability profile (affected by the Coriolis approximation) has a marginal influence.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Regional Climate Models (RCMs) are increasingly used to add small-scale processes at higher grid resolution that are not represented by their Lateral Boundary Conditions (LBCs). Rossby Centre regional atmospheric model, RCA4, has downscaled three Global Climate Models (GCMs), namely, CNRM-CM5, EC-EARTH and GFDL-ESM2M in the COordinated Regional climate Downscaling EXperiment (CORDEX) framework for Middle East North Africa (MENA) and South Asia (SA) domains. Arabian Peninsula is covered in both MENA and SA simulations, which gives a unique opportunity to study the effects of CORDEX domain and LBCs on the simulation of temperature and precipitation by RCM. It is examined by calculating the differences between MENA and SA simulations for different driving GCMs in the historical (1976–2005) and future (2071–2100) periods under RCP8.5 emission scenario, for both summer (dry) and winter (wet) seasons. RCA4 performs generally well when simulating the observed temperature and precipitation patterns, with some local wet biases over Asir Mountains and cold bias over the north eastern parts of Saudi Arabia. The simulations of temperature seem to be very sensitive to the simulation domain (i.e., MENA and SA) and less sensitive to different LBCs, whereas in case of precipitation LBCs seems to play a dominant role. The MENA simulations generally project about 2 °C warmer and drier climate compared to SA simulations by the end of this century, which is comparable to the differences arising due to different LBCs and climate change.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study investigates the diurnal variation of the warm season precipitation simulated by the Goddard Earth Observing System version 5 atmospheric general circulation model for 2 years (2005–2006) at a horizontal resolution of 10 km. The simulation was validated with the satellite-derived Tropical Rainfall Measuring Mission (TRMM) 3B42 precipitation data and the Modern-Era Retrospective analysis for Research and Applications atmospheric reanalysis for atmospheric winds and moisture. The simulation is compared with the coarse-resolution run in 50 km to examine the impacts driven by resolution change. Overall, the 10 km model tends to reproduce the important features of the observed diurnal variation, such as the amplitude and phase at which precipitation peaks in the evening on land and in the morning over the ocean, despite an excessive amplitude bias over land. The model also reproduces the realistic propagation patterns of precipitation in the vicinity of ocean coasts and major mountains. The regional characteristics of the diurnal precipitation over two regions, the Bay of Bengal and the Great Plains in North America, are examined in detail, where the observed diurnal cycle exhibits a systematic transition in the peak phase due to the development and propagation of regional-scale convective systems. The model is able to reproduce this pattern as well as the diurnal variation of low-level wind and moisture convergence; however, it is less effective at representing the nocturnal peak of precipitation over the Great Plains. The model results suggest that increasing the horizontal resolution of the model to 10 km substantially improves the representation of the diurnal precipitation cycle. However, intrinsic model deficiencies in topographical precipitation and the accurate representation of mesoscale convective systems remain a challenge.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The influence of El Niño-Southern Oscillation (ENSO) on the Indian Ocean Dipole (IOD), a coupled ocean–atmosphere mode of interannual climate variability, has been widely investigated over recent decades. However, a latest study indicates that the South China Sea summer monsoon (SCSSM) might also be responsible for IOD formation. Furthermore, an abnormal SCSSM does not always coincide with ENSO during boreal summer (June–August, JJA); consequently, the individual and combined effects of the SCSSM and ENSO on the IOD remain elusive. This study shows that the amplitude of the IOD tends to be much stronger under the coexistence of SCSSM and ENSO than that under individual SCSSM or ENSO events during JJA and autumn. The findings also indicate that the SCSSM and ENSO play the dominant role around the eastern and western poles of the IOD, respectively. An anomalous local Hadley circulation closely related to the stronger SCSSM favors anomalous southeasterly off Sumatra and Java during JJA, which enhance oceanic upwelling and subsequently result in cooling of the sea surface temperature (SST) over this area. Similarly, it can be envisaged that the contemporaneous ENSO could influence JJA SST anomalies over the western Indian Ocean via the Walker circulation coupled with oceanic variations.〈/p〉

Description: 〈p〉In the original publication of the article Fig. 1 was incorrect. The correct Fig. 1 is given below.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Differences between two types of prediction skill estimates over Southern Africa are illustrated to better inform the users of seasonal precipitation forecasts over the region who desire assessments of forecast accuracy. Both seasonal precipitation prediction skill estimates for the African continent south of 15°S during the December–March rainy season are derived from the perfect-model method. The perfect-model method is based on a 40-member ensemble of Community Atmosphere Model version 5 simulations forced by observed time-evolving boundary conditions during 1920–2016. The first skill estimate is based on the verification of an ensemble mean forecast spanning many seasons and therefore unconditional on a single boundary forcing. The second skill estimate is based on the verification of an ensemble mean forecast for a single season and is therefore conditional on that year’s boundary forcing. Unconditional prediction skill calculated in 30-year increments for each of the 40 possible forecasts reveals: (1) large spread in skill among the individual forecasts for any given year and (2) temporal variations in skill for each forecast. The magnitude of conditional prediction skill varies greatly from 1 year to the next, revealing that the boundary conditions offer little prediction skill during some years and comparably large skill during others. The simultaneous behaviors of the El Niño–Southern Oscillation and the subtropical Indian Ocean Dipole are related to the largest conditional precipitation prediction skill years. Unconditional skill estimates may therefore mislead users of forecasts who desire assessments of forecast accuracy. Unconditional skill may be temporally unstable, and unlike conditional skill, is not representative of the skill for a given season.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Cellulose paper was coated with the metal-organic framework MIL-101(Cr) in a chitosan matrix and utilized for thin-film microextraction (TFME). The coated paper possesses excellent extraction efficiency for the triazine herbicides atraton, desmetryn, secbumeton, prometon, ametryn, dipropetryn, and dimethametryn. High-performance liquid chromatography-tandem mass spectrometry was applied to quantify target analytes. The effects of mass ratio of MIL-101(Cr) to chitosan, sample pH value, time of adsorption and desorption, and type and volume of desorption solvent on extraction efficiency were optimized. Under the optimal conditions, the method has limits of detection between 1.5 and 22 ng·L〈sup〉−1〈/sup〉. The recoveries of triazines from spiked tap water, drinking water, lake water and river water range from 77.0 to 125.3%, with relative standard deviations of 〈17.4%.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Cellulose paper was modified with metal-organic framework MIL-101(Cr)/chitosan by using a simple, efficient and environmentally friendly approach. The modified cellulose paper was then used as a novel extraction phase in thin-film microextraction (TFME).〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3889_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This work describes the synthesis of a nanocomposite consisting of Ag〈sub〉2〈/sub〉O, silver nanoparticles and N,S-doped carbon quantum dots (Ag〈sub〉2〈/sub〉O/Ag@NS-CQD). The NS-CQD were prepared by hydrothermal treatment of p-aminobenzenesulfonic acid. They act as both the reducing and stabilizing agent for synthesis of Ag〈sub〉2〈/sub〉O/Ag@NS-CQD. The composite was characterized by UV-vis spectroscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The glassy carbon electrode (GCE) was modified by coating it with Ag〈sub〉2〈/sub〉O/Ag@NS-CQD. It exhibits excellent amperometric response to catechol, typically at a low working potential of around 0.25 V. Under the best experimental conditions, the sensor has a wide linear response (0.2 to 180 μM) and a low detection limit (13 nM; at S/〈em〉N〈/em〉 = 3). The method was applied to analysis of spiked water samples and gave satisfactory results.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of the preparation of the Ag/Ag2O@N,S-doped carbon quantum dots composite using 〈em〉p〈/em〉-aminobenzenesulfonic acid and silver nitrate as the starting materials. The corresponding modified glassy carbon electrode exhibits the excellent amperometric sensing performance toward catechol at pH 7.0 with low detection limit and good selectivity.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3848_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A flower-like Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/GO/CdSe nanodot magnetic hybrid material was produced and applied to magnetic solid-phase extraction of ibuprofen from pharmaceuticals, water, and urine samples. The material was characterized by X-ray diffraction, Raman spectroscopy and field emission scanning electron microscopy and SEM-EDX. The pH value, volume of sample solution, amount of sorbent, type and volume of elution solvent and extraction time were optimized. Following elution with acetone, ibuprofen was quantified by HPLC-DAD detection. The recoveries of ibuprofen from spiked real samples ranged between 87 and 109%, and the intra-day and inter-day relative standard deviations from 1.25 to 3.02%. The limit of detection, limit of quantification and preconcentration factor are 0.36 ng·mL〈sup〉−1〈/sup〉,1.20 ng·mL〈sup〉−1〈/sup〉 and 150, respectively.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of the combination of flower-like Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉/GO/CdSe nanodot-based magnetic solid phase extraction (MSPE) and high-performance liquid chromatography (HPLC) procedure for the extraction and analysis of ibuprofen in pharmaceuticals, water, and urine samples.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3875_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The data presented here are from the Offinso North District Farm Health Study (ONFAHS), a population-based cross-sectional study among vegetable farmers in Ghana. The paper addresses knowledge, pesticide handling practices, and protective measures related to pesticide use by self-reported symptoms for 310 adult farmers who completed a comprehensive questionnaire on pesticide management practices and health. In addition, an inventory was prepared using information supplied by pesticide sellers/dealers in this district. We report that cough and wheezing (but not breathlessness) are positively associated with stirring pesticide preparations with bare hands/drinking water while mixing/applying pesticides, and stirring pesticide preparations with bare hands/drinking water/smoking cigarettes while mixing/applying pesticides. There is a significant exposure-response association between the number of precautionary measures practiced while handling pesticides and cough and wheezing but not with breathlessness. We also found unsafe practices to be associated with sexual dysfunction, nervousness, and lack of concentration. The results also suggest a negative association between practice of any precautionary measure when mixing/applying pesticides and sexual dysfunction, nervousness, and lack of concentration. We found that in spite of the fact that farmers have adequate knowledge about the environment and health effects of pesticides, several unhygienic practices are in widespread use, indicating that knowledge is not necessarily always translated in action. Further action is necessary to promote the safe use of pesticides and to replace existing poor management practices among these and other farmers in Ghana.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A luminescent metal organic framework (LMOF) of type UiO-66-NH〈sub〉2〈/sub〉 was chosen for specific and sensitive detection of trace levels of hypochlorite. Hypochlorite causes the quenching of the blue fluorescence of nano-UiO-66-NH〈sub〉2〈/sub〉 (with excitation/emission maxima at 325/430 nm), and this finding forms the basis for a fluorometric assay for hypochlorite. The method overcomes disadvantages of conventional redox-probes which are interfered by oxidants with oxidation capability stronger than that of hypochlorite. Compared with other fluorescent probes for sensing hypochlorite, UiO-66-NH〈sub〉2〈/sub〉 has a comparable detection limit of 0.3 μmol L〈sup〉−1〈/sup〉 and a broad linearity relationship in the range of 1–8 μmol L〈sup〉−1〈/sup〉. The probe was successfully applied to the detection of hypochlorite in complex water samples and living Hela cells.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of hypochlorite induced quenching of the blue fluorescence of nano-UiO-66-NH〈sub〉2〈/sub〉 (with excitation/emission maxima at 325/430 nm) through energy transfer. It overcomes disadvantages of conventional redox-probes which are interfered by oxidants with oxidation capability stronger than that of hypochlorite.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3806_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A protocol is described for chemical modification of graphene oxide with a Schiff base derived from diethylenetriamine and 2-hydroxy-4-methoxybenzophenone. The base was grafted onto an indium tin oxide (ITO) film and applied to electroanalytical determination of arsenite. Successful grafting was confirmed by Fourier transform-infrared spectroscopy, spectrophotometry, field emission scanning electron microscopy and cyclic voltammetry. Secondly, the coated ITO film served as a working electrode for the stripping voltammetric determination of arsenite. The analytical signal is generated by selective oxidation of metal species via multi-donor sites present in the derivatized Schiff base. The electroanalytical protocol was optimized by investigating the effects of deposition time, working potential, frequency and amplitude of square wave anodic stripping voltammetry. The method has attractive features including (a) the usage of a non-metallic, non-toxic and cost-effective material; (b) improved sensitivity (with limit of detection as low as 156 pM) due to better adsorption of arsenite in the Schiff base pockets on the ITO, and (c) the application to the determination of arsenite in real samples.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of the fabrication of a Schiff base-functionalized graphene oxide on an indium tin oxide (SB@SiO2@GO@ITO) electrode for selective electrochemical sensing of arsenite due to adsorption on multi-donor sites.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3807_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Atrazine is a synthetic herbicide applied to control broadleaf weeds in different crops. In many parts of the world, atrazine is mainly applied for controlling weeds in maize fields. However, studies on the possible adverse effects of atrazine on maize crop can hardly be found in literature. The present study was therefore conducted to evaluate the effect of atrazine on different characteristics of maize seedlings including germination, growth, chlorophyll contents, soluble sugars, proteins and proline levels, ions accumulation, cell viability, and cell injury. In addition, the effects of atrazine on reactive oxygen species (ROS) accumulation and antioxidant enzymes activities in maize seedlings were estimated. It was found that at high concentration, atrazine slightly but significantly inhibited seed germination and growth of maize seedlings. Light-harvesting pigments (chlorophylls 〈em〉a〈/em〉 and 〈em〉b〈/em〉, and total carotenoids) exhibited a higher sensitivity to atrazine and were negatively impacted by atrazine at doses above 50 ppm. Atrazine caused an increase in soluble sugars at all tested doses and decrease in soluble proteins at the highest tested dose. Exposure of maize seedlings to atrazine resulted in an increased cell injury and decreased cell viability. Atrazine did not affect the concentration of Na〈sup〉+〈/sup〉, K〈sup〉+〈/sup〉, and Ca〈sup〉2+〈/sup〉 ions in maize seedlings to any greater extent; however, some minor changes were observed in some cases. An increase in the stress marker, proline, was found upon exposure to atrazine. The observed effects of atrazine in maize seedlings can be attributed to oxidative stress as revealed by an increase in H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 content and higher activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) enzymes in atrazine-treated seedlings. The present investigation concludes that atrazine has the potential to adversely affect germination and growth of maize seedlings by inducing oxidative stress that causes increased cell injury and decreased cell viability as well as impairs the concentration of light-harvesting pigments.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study discusses the performance of various planetary boundary layer parameterization (PBL) schemes—the Quasi-Normal Scale Elimination (QNSE), the University of Washington Moist Turbulence (UWMT), and the Yonsei University (YSU)—for the simulation of rapidly developing North Atlantic (NA) mid-latitude winter storms. Sensitivity experiments with the three PBL schemes, YSU, QNSE, and UWMT, indicate that there are minor differences at the center of the storm while simulating the evolution of the three explosive storms Klaus (21–27 January 2009), Xynthia (25 February–03 March 2010), and Gong (16–20 January 2013). The differences are shown in terms of the central minimum pressure, 10-m wind, specific humidity, CAPE, transitional speed, boundary layer height and frictional velocity of these mid-latitude storms. One of the main result shows the capability of QNSE and UWMT PBL schemes to reproduce accurately both the cyclogenesis and explosive stage for these mid-latitude storms during the winter season, better than YSU scheme. Almost all PBL schemes show dry bias from middle to upper troposphere (600 hPa–250 hPa), while YSU scheme carries this bias at the surface boundary layer, for all simulations. Moreover, QNSE, UWMT and YMSU PBL schemes underestimate the tangential winds for these mid-latitude storms. The 24 h accumulated latent heat flux and precipitation from UWMT scheme show modified results as compared to YSU and QNSE PBL schemes. Overall results show the superiority of QNSE and UWMT PBL schemes for an accurate simulation of the explosive stage of these North Atlantic winter storms.〈/p〉

Description: 〈p〉The original version of this article unfortunately contained an error. All “〈strong〉50s〈/strong〉” and “〈strong〉70s〈/strong〉” were replaced by “〈strong〉1950s〈/strong〉” and “〈strong〉1970s〈/strong〉” throughout the published paper.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The functional root traits of 〈em〉Pyrus pyraster〈/em〉 (L.) Burgsd. and 〈em〉Sorbus domestica〈/em〉 L. during early growth stages were evaluated. The aim of the study was to identify the functional traits of root systems that determine the adaptability of these woody species to drought conditions. The experiment was carried out under the controlled environment of a growth chamber. The root systems were analyzed using WinRhizo software. Several functional root traits were identified, including specific root length, root surface area, root length, root volume, root-to-shoot mass ratio (R:S), fine root (〈em〉ϕ〈/em〉 ˂ 2 mm) volume, coarse root (〈em〉ϕ〈/em〉 〉 2 mm) volume, and fine-to-coarse root volume ratio (F/C). In drought, 〈em〉P. pyraster〈/em〉 maintained the absorptive root surface unchanged, when increased the volume of the fine root fraction. The different strategy of adaptation to drought has been confirmed for 〈em〉S. domestica〈/em〉, which accumulated more dry mass in the root system in comparison to aboveground organs (significant increase of R:S ratio). The functional root traits analyzed here were species-dependent. The key functional traits that indicate the responses of studied tree taxa to drought conditions include root thickening, F/C, and R:S. Increased values of these parameters indicate the investment of the plant towards root extension. A higher proportion of fine roots increases the absorbing surface of the root system, thereby promoting water uptake from the soil.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A self-powered photoelectrochemical (PEC) aptamer probe is presented for the determination of oxytetracycline (OTC). The assay is based on the use of g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and NiO nanocrystals (NCs) which form a heterojunction. The latter was prepared by two-step hydrothermal pyrolysis by using the ionic liquid 1-hydroxyethyl-3-methylimidazole chloride which functions as a morphological template to form NiO NCs. The heterojunction exhibits much better electronic conductivity, wider absorption range, higher electron-hole-separation productivity, and stronger photocurrent compared to plain g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉. The heterojunction was adopted to construct a self-powered PEC aptamer probe for OTC detection. An OTC-binding aptamer was immobilized on the heterojunction and the probe was constructed. The aptamer on the probe binding with OTC can form steric hindrance for transmitting of electrons and cause the PEC signal change depending on the OTC concentration. The photocurrent decreases with increasing OTC concentration in the 0.01 to 100 nM concentration range and its detection limit is 4 pM (at S/〈em〉N〈/em〉 = 3).〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of a self-powered photochemical aptamer probe. The probe performs enhanced ability for oxytetracycline (OTC) determination due to the formation of NiO nanocrystals/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 (NiO NCs/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) heterojunction and the specification recognition of the aptamer.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3856_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The peroxidase-like activity of hollow Prussian Blue nanocubes (hPBNCs) is used, in combination with the enzyme alcohol oxidase (AOx), in a colorimetric ethanol assay. Different from other nanozymes, the large cavity structure of the hPBNCs provides a larger surface and more binding sites for AOx to be bound on their surface or in the pores. This extremely enhances the sensitivity of the assay system. In the presence of ethanol, AOx is capable of catalyzing the oxidation of alcohols to aldehydes, accompanied by the generation of hydrogen peroxide (H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉). The hPBNCs act as peroxidase mimics and then can catalyze the oxidation of 3,3′5,5′-tetramethylbenzidine (TMB) by H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉, resulting in a color change of the solution from colorless to blue with a strong absorption at 652 nm. The lower detection limit for ethanol is 1.41 μg∙mL〈sup〉−1〈/sup〉. Due to the high catalytic activity of hPBNCs in weakly acidic and neutral solutions, the system was successfully applied to the determination of ethanol in mice blood. This is critically important for studying the alcohol consumption and monitoring the ethanol toxicokinetics.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of hollow Prussian Blue nanocubes (hPBNCs) used as both a peroxidase mimetic and as a carrier for alcohol oxidase. Utilizing hPBNCs along with the ethanol conversion enzyme, a sensitive colorimetric assay for ethanol was developed and applied to blood samples with satisfactory results.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3826_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Prussian Blue nanoparticles were deposited on g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanosheets. The resulting nanocomposite possesses peroxidase-like (POx) activity and can catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine at room temperature in the presence of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉. This leads to formation of a blue product with an absorption maximum at 650 nm. The formation of the Prussian Blue nanoparticles on the g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanosheets, and the POx-like activity of the composite were characterized in detail. The POx mimic was used for determination of L-lactic acid via detection of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 that is produced by the enzyme lactate oxidase (LOx). The assay has a linear range that extends from 5 to 100 μM, and the detection limit is 2.2 μM. The method was successfully applied to the determination of L-lactic acid in spiked human serum.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Ultra-small Prussian Blue (PB) nanoparticles were used to modify g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanosheets, and their peroxidase-like activity was explored for detection of L-lactic acid. LOx represent L-lactate oxidase, and TMB represents 3,3′,5,5′-tetramethylbenzidine.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3834_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Walnut shell was processed for preparing nanoporous carbon, which further underwent element doping in order to boost its performance. A novel electrochemical sensor was then built by using the nitrogen and sulfur co-doped walnut shell carbon (N,S-WSC). Morphology and microstructure of the materials were characterized by scanning electron microscopy and Brunauer-Emmett-Teller (de)sorption which showed that N,S-WSC has a large specific surface with abundant pores. Electrochemical properties of differently modified sensors were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. They demonstrated enhanced conductivity and enlarged surface after N,S co-doping. The modified electrode exhibits good catalytic ability towards paracetamol (ACOP) and p-aminophenol (PAP), and baseline separation of their oxidation peaks (peak potential difference is 0.24 V) allows for simultaneous detection of these two compounds. Under the optimal conditions, the calibration plot is linear in the 0.1 to 220 μM ACOP concentration range, with a 26 nM detection limit. Response to PAP is linear from 1.0 to 300 μM, and the detection limit is 38 nM (at S/N = 3). The sensor was successfully applied to quantify ACOP and PAP in tablets, and the accuracy of results is validated by HPLC.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of a novel electrochemical sensor based on N, S co-doped walnut shell carbon modified glassy carbon electrode for determination of paracetamol and 〈em〉p〈/em〉-aminophenol.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3870_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Multiple applications of nanoparticles (NPs) could result in their potential release into agricultural systems and raised concerns about food safety. The NPs once released in the environment may interact with numerous pollutants, including other NPs. Present study assessed the impact of a single (CuO and ZnO NPs) and binary mixture (CuO+ZnO NPs) on the germination of 〈em〉Raphanus sativus〈/em〉 seeds with a wide range of exposure concentration (0–1000 mg/L). Both the NPs have shown a deleterious effect on seeds at exposure concentration greater than 10 mg/L. Antagonistic interaction between effects of CuO and ZnO NPs on seeds was noticed for all the exposed concentrations. CuO NPs showed higher absorption capacity on the seedling surface than ZnO NPs. Internal uptake of Zn in ZnO NP–exposed seedlings was found to be greater than that due to CuO NP–exposed seedlings. Three different types of exposure adversely affected seed germination (reduction in root length, shoot length, and fresh weight). Reduction in growth parameters (length and weight) with concentration was compared using log-logistic dose-response model of “DRC” package of the “R” software, and EC〈sub〉50〈/sub〉 was determined. As per EC〈sub〉50〈/sub〉 values, the toxicity of CuO NPs was found to be maximum followed by CuO+ZnO NPs and then minimum for ZnO NPs. Seedlings accumulated Cu and Zn metals, and higher uptake was recorded for Zn (reported as mg/g seedling dry weight). The order of toxicity was found as CuO NPs 〉 binary mixture (CuO+ZnO) NPs 〉 ZnO NPs. Exposure concentration greater than 10 mg/L resulted in significant toxicity and uptake in germinated seedlings. These findings indicated that exposure of the mixture of NPs during germination might give different effects and thus, further attempts could prove quite beneficial to the literature.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In light of ongoing changes in how humans interact with the environment, it is of great importance to quantitatively assess the impact of land use and cover change (LUCC) on ecosystems. Using a variety of methods, we analyzed land-use patterns and ecosystem service values (ESV) in 1990, 2000, and 2010; normalized difference vegetation index (NDVI) from 1982 to 2010 in the arid region of Northwest China; and quantitatively assessed the effects of LUCC on changes in NDVI and ESV. The results indicate the following: (1) From 1990 to 2010, the rate of increase in the amount of cropland and urban land was highest at 19.13% and 18.25%, respectively, followed by the rate for water cover (5.10%) and forest land (3.55%), while grassland experienced a reduction of 2.25%. (2) From 1990 to 2010, the total ESV increased by 1.82%. Changes in the amount of water cover and cropland were responsible for an increase in ESV of 1.42% and 1.10%, respectively, while the change in the amount of grassland was responsible for a decrease of 1.09%. Based on this, it seems likely that climate variability is a substantial cause of change in ESV. (3) From 1982 to 2010, NDVI showed an overall increase, first increasing significantly between 1982 and 2002 and then decreasing somewhat from 2002 to 2010. From 1990 to 2010, the contribution rate of LUCC to change in total NDVI was 26.74%, indicating that the contribution rate of climate variability to NDVI change was up to 73.26%. Therefore, over those 20 years, climate warming and humidification had an important impact on the development of ecosystems in the arid region of Northwest China.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The suitability of a reference element or normalizer used in assessing soil contamination levels using enrichment factor (EF) is important for soil quality assessment and monitoring. This study evaluated the results of using three reference elements Ti, Fe, and Zr for EF determination of Rb and Sr in soils within treated wastewater discharge vicinity, Central Botswana. The upper continental crust (UCC), world average values (WAV), and the local background values (LBV) were used in EF assessment of eight pedons. The elemental concentrations of the soils were determined with portable X-ray fluorescence (pXRF) analyzer. Relationships between the elements were strongly significant between Rb and Ti (〈em〉r〈/em〉 = 0.600, 〈em〉p〈/em〉 〈 0.01), Rb and Fe (〈em〉r〈/em〉 = 0.735, 〈em〉p〈/em〉 〈 0.01), Sr and Ti (〈em〉r〈/em〉 = 0.545, 〈em〉p〈/em〉 〈 0.01), and Sr and Fe (〈em〉r〈/em〉 = 0.841, 〈em〉p〈/em〉 〈 0.01). Second-level correlation analysis between contamination factor (CF) and EF levels showed Zr as the best reference element for Rb and Sr in the soils. Results from this study provide baseline knowledge necessary for contamination assessment and monitoring of soils with similar environmental conditions.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper presents an electrochemical sensor for Cr(VI) (chromate ion) in water. A disposable screen-printed electrode was modified with gold nanostars (AuNSs) that were synthesized by Good’s buffer method. Linear sweep voltammetry (LSV) was employed for the detection of Cr(VI) in 0.1 M sulfuric acid solution. The AuNSs are shown to provide higher current response to Cr(VI) than spherically shaped gold nanoparticles. The sensor gives the strongest response at a scan rate of 0.05 V (vs Ag/AgCl) and exhibits minimal interference from other electroactive species. The linear range extends from 10 to 75,000 ppb, and the limit of detection is 3.5 ppb. This is well below the provisional guideline value given by the World Health Organization. Excellent recoveries (ranging between 95 and 97%) were found when analyzing contaminated ground water samples obtained from a site situated in Wellesley, MA.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic presentation of preparation of gold nanostars (AuNS) on carbon paste screen printed electrode (CPSPE) by drop casting and electrochemical detection of chromium (VI) using linear sweep voltammetry (LSV).〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3847_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Fluorescent polymer dots (PDs) with maximum excitation/emission wavelengths of 410/515 nm were prepared in water solution from 1,4-benzoquinone and ethylenediamine. The green fluorescence of these PDs is screened off by the red-colored oxidation product (PPDox, maximum absorption at 510 nm) formed by horseradish peroxidase (HRP)-catalyzed oxidation of 〈em〉p〈/em〉-phenylenediamine (PPD). It causes the reduction of the fluorescence intensity of the PDs due to spectral overlap and an inner filter effect (IFE). If glucose is enzymatically oxidized under the formation of H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉, the formed H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 can be quantified by the above IFE. The assay for HRP activity and glucose have detection limits of 0.2 U·L〈sup〉−1〈/sup〉 and 0.1 μM, respectively. The nanoprobe was further extended to an immunosorbent assay (ELISA) for the determination of insecticidal Cry1Ab/Ac protein with a detection limit of 0.25 ng·mL〈sup〉−1〈/sup〉. The ELISA was applied to rice leaf analysis.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphic abstract〈/strong〉 〈em〉 〈div〉Schematic representation of fluorometrict enzyme-linked immunosorbent assay for Cry1Ab/Ac protein detection based on horseradish peroxidase (HRP)-triggered fluorescence quenching of polymer dots (PDs). Quenching is caused by an inner filter effect (IFE) caused by PPDox, the oxidation product of 〈em〉p〈/em〉-phenylenediamine (PPD).〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3831_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The authors describe an electrochemical and an optical method for the determination of As(V) by using iron oxyhydroxide (FeOOH) nanorods that display peroxidase-mimicking activity. The nanorods catalyze the oxidation of substrate ABTS by H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 to form a green product with an absorption maximum at 418 nm. If, however, As(V) is electrostatically adsorbed on the nanorods, the oxidation is gradually inhibited. A colorimetric assay was worked out based on these findings. Response is linear in the 0 to 8 ppb and 8 to 200 ppb As(V) concentration range, and the detection limit is 0.1 ppb. Even higher sensitivity is achieved in an electrochemical method which is based on the excellent electrical conductivity of FeOOH nanorods. Electrochemical analysis of As(V) was achieved by first adsorbing As(V) on the nanorods. This inhibits the ABTS reduction current signal, best measured at a potential of 150 mV (vs. Ag/AgCl). The linear range extends from 0.04 to 200 ppb, and the detection limit is as low as 12 ppt.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of FeOOH nanorod-based colorimetric and electrochemical assays for arsenate (As(V)). As(V) adsorbed on FeOOH nanorods inhibits the peroxidase-mimicking activity of nanorods, and a colorimetric and electrochemical dual-signal assay was constructed to achieve sensitive determination of As(V).〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3863_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sita, a small tropical river originating in the Western Ghats, southwestern India, was chosen for this study to understand the spatial and temporal variability of dissolved trace elements and major ions. Sampling was done in monsoon, post-monsoon and pre-monsoon seasons across the river catchment. Dissolved elements like Zn, Ni, Cu and Co showed high concentrations during monsoon which could be because of the intense chemical weathering of silicate rocks in the catchment, surface runoff and wet atmospheric deposition. In the remaining seasons, the river is fed by the groundwater and anthropogenic effluents which is contributing to higher concentrations of dissolved Pb, Fe and Cd. The results are analysed using factor analysis (SPSS 12), which helped to delineate the sources of metal assemblages. Factor 1 is dominated by major ions (Na, K, Cl, Mg, Ca), which could be naturally sourced from atmospheric deposition and weathering of rocks. Factor 2 is dominated by trace metals (Cd, Pb, Co) and sulphates (SO〈sub〉4〈/sub〉) which may have anthropogenic sources such as the discharge of domestic and industrial effluents and agricultural effluents.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The inconsistent thermal quenching performance of manganese(II)-doped Cs〈sub〉3〈/sub〉Cu〈sub〉2〈/sub〉I〈sub〉5〈/sub〉 microparticles is exploited in a highly sensitive noninvasive optical thermometer. The ratio of the emissions of Cu(II) and Mn(II) ions in the microparticles is highly temperature dependent in the range from 298 to 498 K. The best absolute and relative sensitivities are 0.547 K〈sup〉−1〈/sup〉 and 0.525% K〈sup〉−1〈/sup〉, respectively. The emission spectrum, under 300-nm photoexcitation, has emission peaks at 448 and 556 nm. This is the result of energy transfer between the Cu(II) and Mn(II) ions whose efficiency can reach up to 57% when the Mn(II) ion concentration is 2 mol%. The emission color of the microparticles changes from cyan to green when increasing the temperature from 298 to 498 K.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Synthesis of novel Mn(II)-doped Cs〈sub〉3〈/sub〉Cu〈sub〉2〈/sub〉I〈sub〉5〈/sub〉 thermochromic halides with admirable luminescent behaviors for high sensitive ratiometric thermometry and safety sign in high temperature environment.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3881_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉An optical method for determination of Hg(II) is described that exploits the aggregation of gold nanoparticles (AuNPs) under dark-field microscope (DFM) observation. This assay is based on the use of a Hg(II)-specific aptamer, AuNPs modified with complementary DNA strands, and exonuclease I (Exo I). In the absence of Hg(II), the added dsDNA prevents salt-induced aggregation of the green-colored AuNPs. If Hg(II) is added, the aptamer will capture it to form T-Hg(II)-T pairs, and the complementary strand is digested by Exo I. On addition of a solution of NaCl, the AuNPs will aggregate. This is accompanied by a color change from green to orange/red) in the dark-field image. By calculating the intensity of the orange/red dots in the dark-field image, concentration of Hg(II) can be accurately determined. The limit of detection is as low as 36 fM, and response is a linear in the 83 fM to 8.3 μM Hg(II) concentration range.〈/p〉 〈p〉 〈span〉 〈caption〉 〈strong〉Graphical abstract〈/strong〉 〈em〉 〈div〉Schematic representation of a colorimetric assay for Hg(II) based on the use of a mercury(II)-specific aptamer, gold nanoparticles modified with complementary DNA strands, and exonuclease I.〈/div〉 〈/em〉 〈/caption〉 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/604_2019_3876_Figa_HTML.png"〉 〈/span〉 〈/span〉 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sequestration of atmospheric carbon-dioxide in biospheric carbon (C) pools is a key strategy towards climate change mitigation. Soil is a huge C reservoir and its storage potential varies greatly with forest types. Therefore, in the present study, the soil organic carbon (SOC) storage pattern was assessed from 70 plots laid at three selected forest types comprising seven study sites at Kanyakumari Wildlife Sanctuary, Western Ghats, India: tropical dry deciduous (TDD I and TDD II), tropical semi-evergreen (TSE I and TSE II) and tropical evergreen forest (TEF I, TEF II and TEF III) at three depths (0–10, 10.1–20 and 20.1–30 cm). Statistical analyses were performed to understand the relationships between SOC stocks with other predictor variables. The SOC stock varied markedly with forest type and site-wise. The SOC ranged from 58 (TEF III) to 123.6 (TDD I) Mg C/ha with a mean of 84.9 ± 4.4 Mg C/ha at 0–30 cm depth. SOC stock decreased, while soil bulk density increased with increase in soil depth. The TDD forest type (115.6 Mg C/ha) stocked the highest SOC compared to TEF (75.1 Mg C/ha) and TSE (68.9 Mg C/ha) forest types. Of the total SOC stock (0–30 cm), 44.2, 32.0 and 23.8% were stored in 0–10, 10.1–20 and 20.1–30 cm respectively in all the forest types. In contrast, litter C stock were high in TEF and TSE forest types and low in TDD forest type. SOC showed significant (〈em〉P〈/em〉 〈 0.01) negative relationships with bulk density, litter C, and vegetation attributes. The SOC stock stored in the study sites amount to 212.9 (TEF III) to 453.6 (TDD I) Mg of CO〈sub〉2〈/sub〉 equivalents. The present study reveals that forest type and site characteristics have a profound impact on SOC stock, which would, in turn, exert a great bearing on the ecosystem C cycling. These results would also enhance our ability to evaluate the role of these forest types in soil C sequestration and for developing and validating SOC models for tropical forest ecosystems.〈/p〉