ALBERT

Beschreibung: When cumulonimbus clouds aggregate, developing into a single entity with precipitation covering a horizontal scale of hundreds of kilometers, they are called mesoscale convective systems (MCSs). They account for much of Earth’s precipitation, generate severe weather events and flooding, produce prodigious cirriform anvil clouds, and affect the evolution of the larger-scale circulation. Understanding the inner workings of MCSs has resulted from developments in observational technology and modeling. Time–space conversion of ordinary surface and upper-air observations provided early insight into MCSs, but deeper understanding has followed field campaigns using increasingly sophisticated radars, better aircraft instrumentation, and an ever-widening range of satellite instruments, especially satellite-borne radars. High-resolution modeling and theoretical insights have shown that aggregated cumulonimbus clouds induce a mesoscale circulation consisting of air overturning on a scale larger than the scale of individual convective up- and downdrafts. These layers can be kilometers deep and decoupled from the boundary layer in elevated MCSs. Cooling in the lower troposphere and heating aloft characterize the stratiform regions of MCSs. As a result, long-lived MCSs with large stratiform regions have a top-heavy heating profile that generates potential vorticity in midlevels, thus influencing the larger-scale circulation within which the MCSs occur. Global satellite data show MCSs varying in structure, depending on the prevailing large-scale circulation and topography. These patterns are likely to change with global warming. In addition, environmental pollution affects MCS structure and dynamics subtly. Feedbacks of MCSs therefore need to be included or parameterized in climate models.

Beschreibung: The central change in understanding of the ocean circulation during the past 100 years has been its emergence as an intensely time-dependent, effectively turbulent and wave-dominated, flow. Early technologies for making the difficult observations were adequate only to depict large-scale, quasi-steady flows. With the electronic revolution of the past 50+ years, the emergence of geophysical fluid dynamics, the strongly inhomogeneous time-dependent nature of oceanic circulation physics finally emerged. Mesoscale (balanced), submesoscale oceanic eddies at 100-km horizontal scales and shorter, and internal waves are now known to be central to much of the behavior of the system. Ocean circulation is now recognized to involve both eddies and larger-scale flows with dominant elements and their interactions varying among the classical gyres, the boundary current regions, the Southern Ocean, and the tropics.

Beschreibung: Although atmospheric observing systems were already an important part of meteorology before the American Meteorological Society was established in 1919, the past 100 years have seen a steady increase in their numbers and types. Examples of how observing systems were developed and how they have enabled major scientific discoveries are presented. These examples include observing systems associated with the boundary layer, the upper air, clouds and precipitation, and solar and terrestrial radiation. Widely used specialized observing systems such as radar, lidar, and research aircraft are discussed, and examples of applications to weather forecasting and climate are given. Examples drawn from specific types of chemical measurements, such as ozone and carbon dioxide, are included. Sources of information on observing systems, including other chapters of this monograph, are also discussed. The past 100 years has been characterized by synergism between societal needs for weather observations and the needs of fundamental meteorological research into atmospheric processes. In the latter half of the period, observing system improvements have been driven by the increasing demands for higher-resolution data for numerical models, the need for long-term measurements, and for more global coverage. This has resulted in a growing demand for data access and for integrating data from an increasingly wide variety of observing system types and networks. These trends will likely continue.

Beschreibung: The polar regions present several unique challenges to meteorology, including remoteness and a harsh environment. We summarize the evolution of polar meteorology in both hemispheres, beginning with measurements made during early expeditions and concluding with the recent decades in which polar meteorology has been central to global challenges such as the ozone hole, weather prediction, and climate change. Whereas the 1800s and early 1900s provided data from expeditions and only a few subarctic stations, the past 100 years have seen great advances in the observational network and corresponding understanding of the meteorology of the polar regions. For example, a persistent view in the early twentieth century was of an Arctic Ocean dominated by a permanent high pressure cell, a glacial anticyclone. With increased observations, by the 1950s it became apparent that, while anticyclones are a common feature of the Arctic circulation, cyclones are frequent and may be found anywhere in the Arctic. Technology has benefited polar meteorology through advances in instrumentation, especially autonomously operated instruments. Moreover, satellite remote sensing and computer models revolutionized polar meteorology. We highlight the four International Polar Years and several high-latitude field programs of recent decades. We also note outstanding challenges, which include understanding of the role of the Arctic in variations of midlatitude weather and climate, the ability to model surface energy exchanges over a changing Arctic Ocean, assessments of ongoing and future trends in extreme events in polar regions, and the role of internal variability in multiyear-to-decadal variations of polar climate.

Beschreibung: The field of atmospheric science has been enhanced by its long-standing collaboration with entities with specific needs. This chapter and the two subsequent ones describe how applications have worked to advance the science at the same time that the science has served the needs of society. This chapter briefly reviews the synergy between the applications and advancing the science. It specifically describes progress in weather modification, aviation weather, and applications for security. Each of these applications has resulted in enhanced understanding of the physics and dynamics of the atmosphere, new and improved observing equipment, better models, and a push for greater computing power.

Beschreibung: Over the past century, the atmospheric and related sciences have seen incredible advances in our understanding of Earth’s environment and our ability to monitor and predict its behavior. These advances have had a profound impact on society and have been integrated into every aspect of daily life. The American Meteorological Society (AMS) has been instrumental in supporting these advances throughout its first 100 years of existence as a scientific and professional society serving the community of professionals in the atmospheric and related oceanic and hydrologic sciences. AMS has provided opportunities for researchers and practitioners to share their scientific findings and build fruitful collaborations to further the science and its application. Through strategic initiatives at key points in its history, AMS has pushed the science forward—highlighting areas ripe for development, creating frameworks for interdisciplinary interactions, and providing innovative approaches to the dissemination of research results. As a society made up of the scientific community and led by many of the most prominent scientists of their time, AMS has been able to respond to, and often anticipate, the needs of its community.

Beschreibung: A century ago, meteorologists regarded tropical cyclones as shallow vortices, extending upward only a few kilometers into the troposphere, and nothing was known about their physics save that convection was somehow involved. As recently as 1938, a major hurricane struck the densely populated northeastern United States with no warning whatsoever, killing hundreds. In the time since the American Meteorological Society was founded, however, tropical cyclone research blossomed into an endeavor of great breadth and depth, encompassing fields ranging from atmospheric and oceanic dynamics to biogeochemistry, and the precision and scope of forecasts and warnings have achieved a level of success that would have been regarded as impossible only a few decades ago. This chapter attempts to document the extraordinary progress in tropical cyclone research over the last century and to suggest some avenues for productive research over the next one.

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Progress in Oceanography, Volume 170〈/p〉 〈p〉Author(s): Alba María Martínez–Pérez, Teresa S. Catalá, Mar Nieto–Cid, Jaime Otero, Marta Álvarez, Mikhail Emelianov, Isabel Reche, Xosé Antón Álvarez–Salgado, Javier Arístegui〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fluorescent dissolved organic matter (FDOM) in the Mediterranean Sea was analysed by excitation–emission matrix (EEM) spectroscopy and parallel factor (PARAFAC) analysis during the cruise HOTMIX 2014. A 4–component model, including 3 humic–like and 1 protein–like compounds, was obtained. To decipher the environmental factors that dictate the distributions of these components, we run generalized additive models (GAMs) in the epipelagic layer and an optimum multiparametric (OMP) water masses analysis in the meso– and bathypelagic layers. In the epipelagic layer, apparent oxygen utilization (AOU) and temperature presented the most significant effects on the variability of the marine humic-like peak M fluorescence, suggesting that its distribution was controlled by the net community respiration of organic matter and photobleaching. On the contrary, the variability of the soil humic-like peak E and the protein–like peak T fluorescence was explained mainly by the prokaryotic heterotrophic abundance, which decreased eastwards. In the meso– and bathypelagic layers, water mass mixing and basin–scale mineralization processes explained 〉72% and 63% of the humic–like and protein–like fluorescence variability, respectively. When analysing the two basins separately, the OMP model offered a better explanation of the distribution of fluorescence in the eastern Mediterranean Sea, as expected from the reduced biological activity in this ultra–oligotrophic basin. Furthermore, while western Mediterranean deep waters display the usual trend in the global ocean (increase of humic–like fluorescence and decrease of protein–like fluorescence with higher AOU values), the eastern Mediterranean deep waters presented an opposite trend. Different initial fluorescence intensities of the water masses that mix in the eastern basin, with Adriatic and Aegean origins, seem to be behind this contrasting pattern. The analysis of the transect–scale mineralization processes corroborate this hypothesis, suggesting a production of humic–like and a consumption of protein–like fluorescence in parallel with water mass ageing. Remarkably, the transect–scale variability of the chromophoric dissolved organic matter (CDOM) absorbing at the excitation wavelength of the humic–like peak M indicates an unexpected loss with increasing AOU, which suggests that the consumption of the non–fluorescent fraction of CDOM absorbing at that wavelength exceeded the production of the fluorescent fraction observed here.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochimica et Biophysica Acta (BBA) - General Subjects, Volume 1863, Issue 2〈/p〉 〈p〉Author(s): Mathilde Ménard, Florent Meyer, Ksenia Parkhomenko, Cédric Leuvrey, Grégory Francius, Sylvie Bégin-Colin, Damien Mertz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Human serum albumin (HSA) nanoparticles emerge as promising carriers for drug delivery. Among challenges, one important issue is the design of HSA nanoparticles with a low mean size of ca. 50 nm and having a high drug payload. The original strategy developed here is to use sacrificial mesoporous nanosilica templates having a diameter close to 30 nm to drive the protein nanocapsule formation. This new approach ensures first an efficient high drug loading (ca. 30%) of Doxorubicin (DOX) in the porous silica by functionalizing silica with an aminosiloxane layer and then allows the one-step adsorption and the physical cross-linking of HSA by modifying the silica surface with isobutyramide (IBAM) groups. After silica template removal, homogenous DOX-loaded HSA nanocapsules (30–60 nm size) with high drug loading capacity (ca. 88%) are thus formed. Such nanocapsules are shown efficient in multicellular tumor spheroid models (MCTS) of human hepatocarcinoma cells by their significant growth inhibition with respect to controls. Such a new synthesis approach paves the way toward new protein based nanocarriers for drug delivery.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0304416518303416-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Data in Brief, Volume 21〈/p〉 〈p〉Author(s): Juan A. Parga, Ana I. Rodriguez-Perez, Maria Garcia-Garrote, Jannette Rodriguez-Pallares, Jose L. Labandeira-Garcia〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This article describes the effect of the oxidative stress inducers Angiotensin II and 6-hydroxydopamine (6-OHDA) on different cell lines. The levels of expression Angiotensin type 1 and type 2 receptors in different dopaminergic cell lines are shown. The data indicate that treatment with Angiotensin II and 6-OHDA increases the production of reactive oxygen species (ROS) and decreases cell viability. NRF2 is a transcription factor induced by ROS. We provide data that NRF2 overexpression increases cell viability in response to oxidative stress inducers compared to control cells, and that these inducers can, both separately and in combination, enhance the expression of NRF2-regulated genes heme oxygenase 1 (Hmox1), NAD(P)H quinone dehydrogenase 1 (Nqo1) and Kruppel like factor 9 (Klf9). Interpretation of these data and additional information is presented in the research article “Angiotensin II induces oxidative stress and upregulates neuroprotective signaling from the NRF2 and KLF9 pathway in dopaminergic cells“ (Parga et al., 2018) [1].〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Cytokine, Volume 113〈/p〉 〈p〉Author(s): Agnieszka Swidnicka-Siergiejko, Urszula Wereszczynska-Siemiatkowska, Andrzej Siemiatkowski, Justyna Wasielica-Berger, Jacek Janica, Barbara Mroczko, Andrzej Dabrowski〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈h6〉Introduction〈/h6〉 〈p〉The presence of esophageal varices in liver cirrhosis indicates clinically significant portal hypertension (PH), that results from structural and dynamic changes in the liver and systemic circulation including the activation of several fibrotic and inflammatory pathways. We assessed if interleukin-18 (IL-18) and transforming growth factor-β1 (TGF-β1) serum levels can be used as PH markers and reflect its severity.〈/p〉 〈/div〉 〈div〉 〈h6〉Material and methods〈/h6〉 〈p〉IL-18 and TGF-β1 peripheral blood levels were analyzed in 83 cirrhotic patients with esophageal varices compared to healthy individuals, in relation to MELD and Child-Pugh scores, laboratory and Doppler ultrasound parameters, and non-selective beta-blocker therapy (NSBB).〈/p〉 〈/div〉 〈div〉 〈h6〉Results〈/h6〉 〈p〉IL-18 concentration was significantly higher in cirrhotic patients, while TGF-β1 concentration was lower than in controls. MELD score correlated positively with IL-18 levels and negatively with TGF-β1 levels. IL-18 levels correlated positively with bilirubin, INR, ALT and AST levels, and negatively with albumin levels and erythrocyte count. TGF-β1 levels correlated positively with platelet count, leukocyte, and erythrocyte count, and negatively with bilirubin levels and prothrombin time. Moreover, significant correlations were found: between IL and 18 levels and portal, mesenteric superior, and splenic vein velocity, and between TGF-β1 levels and splenic vein diameter and spleen size. In a subgroup of patients, IL-18 levels significantly decreased after NSBB.〈/p〉 〈/div〉 〈div〉 〈h6〉Conclusion〈/h6〉 〈p〉The observed imbalance of peripheral IL-18 and TGF-β1 levels indicates clinically significant PH associated with the presence of esophageal varices in cirrhosis. The correlation of IL-18 levels with liver failure indicators and decrease with NSBB suggest an important role of IL-18 in disease progression and its potential use as noninvasive test for PH assessment.〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, Volume 1866, Issue 1〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solid State Ionics, Volume 327〈/p〉 〈p〉Author(s): W.G. Wang, X.Y. Li, T. Liu, G.L. Hao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The electrical performances and relaxation behaviors of the Na〈sub〉0.525〈/sub〉Bi〈sub〉0.475〈/sub〉TiO〈sub〉2.975〈/sub〉 and Bi-deficient Na〈sub〉0.51〈/sub〉Bi〈sub〉0.48〈/sub〉TiO〈sub〉2.975〈/sub〉 sample were investigated. The grain conductivity of the Na〈sub〉0.525〈/sub〉Bi〈sub〉0.475〈/sub〉TiO〈sub〉2.975〈/sub〉 sample is able to reach 1.51 × 10〈sup〉−3〈/sup〉 S/cm at 673 K. In the temperature range of measurement, the grain conductivity of the Bi-deficient Na〈sub〉0.51〈/sub〉Bi〈sub〉0.48〈/sub〉TiO〈sub〉2.975〈/sub〉 sample is lower than that of the Na〈sub〉0.525〈/sub〉Bi〈sub〉0.475〈/sub〉TiO〈sub〉2.975〈/sub〉 sample. By the internal friction and dielectric relaxation spectrum, the activation energy and relaxation time at infinite temperature were determined as (0.82 eV, 2.47 × 10〈sup〉−14〈/sup〉 s), (0.67 eV, 5.82 × 10〈sup〉−12〈/sup〉 s) and (0.85 eV, 5.8 × 10〈sup〉−13〈/sup〉 s), (0.52 eV, 2.55 × 10〈sup〉−10〈/sup〉 s) for the Na〈sub〉0.525〈/sub〉Bi〈sub〉0.475〈/sub〉TiO〈sub〉2.975〈/sub〉 and Na〈sub〉0.51〈/sub〉Bi〈sub〉0.48〈/sub〉TiO〈sub〉2.975〈/sub〉 samples at the different temperature regions. In the Na〈sub〉0.525〈/sub〉Bi〈sub〉0.475〈/sub〉TiO〈sub〉2.975〈/sub〉 compound, there is larger specific free volume, higher mobile oxygen vacancy content and better oxygen vacancy mobility, which cause the higher grain conductivity in the Na〈sub〉0.525〈/sub〉Bi〈sub〉0.475〈/sub〉TiO〈sub〉2.975〈/sub〉 compound. To some extent, by the Bi-deficient method, oxygen vacancies can be introduced into the Na〈sub〉0.51〈/sub〉Bi〈sub〉0.48〈/sub〉TiO〈sub〉2.975〈/sub〉 compound and the grain conductivity may be improved, but the other side of Bi-deficiency harms the oxygen vacancy diffusion capacities in the Na〈sub〉0.5〈/sub〉Bi〈sub〉0.5〈/sub〉TiO〈sub〉3〈/sub〉 compound.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solid State Ionics, Volume 327〈/p〉 〈p〉Author(s): Yonrapach Areerob, Ju Yong Cho, Won Kweon Jang, Kwang Youn Cho, Won-Chun Oh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A cost effective and efficient alternative counter electrode (CE) to replace commercially existing platinum (Pt)-based CEs for dye-sensitized solar cells (DSSCs) is necessary to make DSSCs competitive. Herein, we report the model-controllable synthesis of Graphene-La〈sub〉6〈/sub〉W〈sub〉2〈/sub〉O〈sub〉15〈/sub〉 doped NiSe-CoSe quantum dot (GLW-NiCoSe) nanosheets with various NiCoSe content via simple hydrothermal method and used as CE for DSSC application. Electrochemical impedance spectroscopy (EIS) results confirmed that the as-synthesized GLW-NiCoSe nanosheets quantum dot exhibited good electrocatalytic properties and a low charge transfer resistance at the electrolyte-electrode interface. In addition, Thermal images and Photocurrent also demonstrate stability effect of material with more exposed edge sites and appropriate NiCoSe ratio. GLW-NiCoSe nanosheets performed rough surfaces, well-defined interior voids, large specific surface areas and outstanding catalytic actives. Finally, the mechanism of this material has been reported. All of these results showed a high energy conversion efficiency of up to 8%, which was comparable to the Pt CE (7%). The simple fabricated and good electrocatalytic properties of GLW-NiCoSe nanosheets make them as an alternative CE for DSSCs.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0167273818304910-ga1.jpg" width="314" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solid State Ionics, Volume 327〈/p〉 〈p〉Author(s): Ho-Young Jung, Geon-O Moon, T. Sadhasivam, Chang-Soo Jin, Won-Shik Park, Hee-Tak Kim, Sung-Hee Roh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To confirm the viability of a porous polyethylene (PE) separator for using in vanadium redox flow batteries (VRFBs), we conduct a comparative electroanalytical and chemical stability studies of the PE separator and Nafion 212 membrane. We characterize the physicochemical properties of the separator, such as water uptake, dimensional change, and ion conductivity, and analyze its structural and compositional features using thermogravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy. We also test the chemical stability of the separator against highly oxidative V〈sup〉5+〈/sup〉 ions and the cell performance of VRFB using PE separator to assess practical applicability. In chemical stability, the change of VO〈sub〉2〈/sub〉〈sup〉+〈/sup〉 ion to VO〈sup〉2+〈/sup〉 ion is considerably lowered by the PE separator (0.01 mmol/L) than the Nafion 212 (0.27 mmol/L), which indicates that the PE separator possesses higher chemical stability. The energy efficiency of the VRFB with the PE separator is lower than that obtained with Nafion 212. However, the chemical stability of PE separator is 27 times higher than that of Nafion 212, indicating that its use will promote the long-term operation of the VRFB system. Hence, the PE separator can be considered a cost-effective option for VRFB operation, with appropriate modifications to its thickness, surface properties and pore structure.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface Science, Volume 681〈/p〉 〈p〉Author(s): Qingjun Chen, Ingeborg-Helene Svenum, Ljubisa Gavrilovic, De Chen, Edd A. Blekkan〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Trace amounts of potassium (K) have a significant influence on the activity and selectivity of cobalt-based catalysts in Fischer–Tropsch synthesis (FTS), in which hydrogen adsorption and dissociation is one of the initial and most important steps. In this work, hydrogen adsorption and dissociation behavior on typical facets ((0001), (10–11), (10–12), (10–15) and (11–20)) of hcp Co with and without adsorbed K were systematically studied. H〈sub〉2〈/sub〉 molecular adsorption results showed that H〈sub〉2〈/sub〉 mainly adsorbed in the perpendicular mode and close to the state of free H〈sub〉2〈/sub〉. Different facets and pre-adsorbed K did not show obvious effects on the H〈sub〉2〈/sub〉 adsorption energy. Atomic hydrogen adsorption was site and facet dependent, but the maximum hydrogen adsorption energy on the different facets of hcp Co were similar (-2.64 to -2.67 eV) with the exception on the (11–20) facet where the adsorption energy was significantly lower (-2.44 eV). K had a slight destabilizing effect on the H atom adsorption on the former Co surfaces due to a very weak repulsive interaction between K and H atoms. The initial H〈sub〉2〈/sub〉 dissociation had negligible energy barriers (0–0.07 eV) on the clean surface of hcp Co, suggesting the direct dissociative adsorption of H〈sub〉2〈/sub〉. The energy barriers for H〈sub〉2〈/sub〉 dissociation are mainly caused by the approach of molecular H〈sub〉2〈/sub〉 towards the Co surface and the rotation of the H〈sub〉2〈/sub〉 molecule from the perpendicular mode to the parallel mode. The H〈sub〉2〈/sub〉 dissociation energy barriers increase by 0.02–0.17 eV after the pre-adsorption of K, indicating a slight inhibition of H〈sub〉2〈/sub〉 dissociation by K. However, the energy barriers for H〈sub〉2〈/sub〉 dissociation in the presence of K were also small (0.05–0.21 eV). This indicates that H〈sub〉2〈/sub〉 dissociates readily at typical Co-based FTS reaction temperatures (210–240 °C), both in the absence and presence of K. Different K species (K and KOH) exhibit similar effects on H〈sub〉2〈/sub〉 dissociation on hcp Co. The B〈sub〉5〈/sub〉 sites on the stepped facets, the preferred sites for K adsorption are not the most favorable site for H〈sub〉2〈/sub〉 dissociation, and K slightly hinders H〈sub〉2〈/sub〉 dissociation at the B〈sub〉5〈/sub〉 site of hcp Co.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0039602818305144-fx1.jpg" width="301" alt="Image, graphical abstract" title="Image, graphical abstract"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Xing-Wei Xiang, Jin-Xing Xiao, Yu-Fang Zhou, Bin Zheng, Zheng-Shun Wen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The black seabream (〈em〉Sparus macrocephlus〈/em〉) is an economically pivotal aquaculture species cultured in China and Southeast Asian countries. To understand the molecular immune mechanisms underlying the response to 〈em〉Vibrio parahaemolyticus〈/em〉, a comparative gene transcription analysis were performed with utilized fresh livers of 〈em〉V. parahaemolyticus〈/em〉-immunized 〈em〉Sparus macrocephlus〈/em〉 with a control group through RNA-Seq technology. A total of 256663 contigs were obtained after excluded the low-quality sequences and assembly. The average length of contigs collected from this research is 1066.93 bp. Furthermore, blast analysis indicates 30747 contigs were annotated based on homology with matches in the NT, NR, gene, and string databases. A gene ontology analysis was employed to classify 21598 genes according to three major functional categories: molecular function, cellular component, and biological process. A total of 14470 genes were discovered in 303 KEGG pathways. RSEM and EdgeR were introduced to estimate 3841 genes significantly different expressed (False Discovery Rate〈0.001) which includes 4072 up-regulated genes and 3771 down-regulated genes. A significant enrichment analysis of these differentially expressed genes and isogenes were conducted to reveal the major immune-related pathways which refer to the toll-like receptor, complement, coagulation cascades, and chemokine signaling pathways. In addition, 92175 potential simple sequence repeats (SSRs) and 121912 candidate single nucleotide polymorphisms (SNPs) were detected and identified sequencely in the 〈em〉Sparus macrocephlus〈/em〉 liver transcriptome. This research characterized a gene expression pattern for normal and the 〈em〉V. parahaemolyticus〈/em〉 -immunized 〈em〉Sparus macrocephlus〈/em〉 for the first time and not only sheds new light on the molecular mechanisms underlying the host-〈em〉V. parahaemolyticus〈/em〉 interaction but contribute to facilitate future studies on 〈em〉Sparus macrocephlus〈/em〉 gene expression and functional genomics.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yi-Hong Chen, Jian-Guo He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The shrimp aquaculture industry is plagued by disease. Due to the lack of deep understanding of the relationship between innate immune mechanism and environmental adaptation mechanism, it is difficult to prevent and control the diseases of shrimp. The shrimp innate immune system has received much recent attention, and the functions of the humoral immune response and the cellular immune response have been preliminarily characterized. The role of environmental stress in shrimp disease has also been investigated recently, attempting to clarify the interactions among the innate immune response, the environmental stress response, and disease. Both the innate immune response and the environmental stress response have a complex relationship with shrimp diseases. Although these systems are important safeguards, allowing shrimp to adapt to adverse environments and resist infection, some pathogens, such as white spot syndrome virus, hijack these host systems. As shrimp lack an adaptive immune system, immunization therapy cannot be used to prevent and control shrimp disease. However, shrimp diseases can be controlled using ecological techniques. These techniques, which are based on the innate immune response and the environmental stress response, significantly reduce the impact of shrimp diseases. The object of this review is to summarize the recent research on shrimp environmental adaptation mechanisms, innate immune response mechanisms, and the relationship between these systems. We also suggest some directions for future research.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Fish & Shellfish Immunology, Volume 84〈/p〉 〈p〉Author(s): Yinnan Mu, Shimin Zhou, Ning Ding, Jingqun Ao, Xinhua Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chemokines are a superfamily of structurally related chemotactic cytokines exerting significant roles in regulating cell migration and activation. Currently, five subgroups of fish specific CXC chemokines, named CXCL_F1-CXCL_F5, have been identified in teleost fish. However, understanding of the functions of these fish specific CXC chemokines is still limited. Here, a new member of fish specific CXC chemokines, 〈em〉Lc〈/em〉CXCL_F6, was cloned from large yellow croaker 〈em〉Larimichthys crocea〈/em〉. Its open reading frame (ORF) is 369 nucleotides long, encoding a peptide of 122 amino acids (aa). The deduced 〈em〉Lc〈/em〉CXCL_F6 protein contains a 19-aa signal peptide and a 103-aa mature polypeptide, which has four conserved cysteine residues (C〈sup〉28〈/sup〉, C〈sup〉30〈/sup〉, C〈sup〉56〈/sup〉, and C〈sup〉72〈/sup〉), as found in other known CXC chemokines. Phylogenetic analysis showed 〈em〉Lc〈/em〉CXCL_F6 formed a separate clade with sequences from other fish species, tentatively named CXCL_F6, distinct from the clades formed by fish CXCL_F1-5 and mammalian CXC chemokines. The 〈em〉Lc〈/em〉CXCL_F6 transcripts were constitutively expressed in all examined tissues and significantly up-regulated in the spleen and head kidney tissues by poly (I:C) and 〈em〉Vibrio alginolyticus〈/em〉. Its transcripts were also detected in primary head kidney leukocytes (HKLs), peripheral blood leucocytes (PBLs), and large yellow croaker head kidney (LYCK) cell line, and significantly up-regulated by poly(I:C), lipopolysaccharide (LPS), and peptidoglycan (PGN) in HKLs. Recombinant 〈em〉Lc〈/em〉CXCL_F6 protein (r〈em〉Lc〈/em〉CXCL_F6) could not only chemotactically attract monocytes/macrophages and lymphocytes from PBLs, but also enhance NO release and expression of proinflammatory cytokines (TNF-α, IL-1β, and CXCL8) in monocytes/macrophages. These results indicate that 〈em〉Lc〈/em〉CXCL_F6 plays a role in mediating the inflammatory response.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 10 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Electrochimica Acta, Volume 296〈/p〉 〈p〉Author(s): Saheed Bukola, Stephen E. Creager〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Transmission rates for protons and deuterons across single-layer graphene embedded in Nafion | graphene | Nafion sandwich structures are measured as a function of temperature in electrochemical hydrogen pump cells. Rates of ion transmission through graphene are obtained in the form of area-normalized ion-transfer resistances, and are interpreted in terms of ion-exchange current densities and standard heterogeneous ion-transfer rate constants. An encounter pre-equilibrium model for the ion-transfer step is then used to provide rate constants for the fundamental microscopic step of ion (proton or deuteron) transmission across graphene. Application of this rate model to interpret variable-temperature data on proton and deuteron transmission rates provides values for the activation energy and pre-exponential factor for the fundamental ion transmission step across graphene. Activation energies obtained from the Arrhenius plots for proton and deuteron transmission are as follows; for proton, E〈sub〉act〈/sub〉 = 48 ± 2 kJ/mole (0.50 ± 0.02 eV) and for deuteron, E〈sub〉act〈/sub〉 = 53 ± 5 kJ/mole (0.55 ± 0.05 eV). The difference between these two values of approximately 5 kJ/mole is in good agreement with the expected difference in vibrational zero-point energies for O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉H and O-D bonds, albeit with some uncertainty given the uncertainties in the activation energy values. Pre-exponential frequency factor values of 8.3 ± 0.4 × 10〈sup〉13〈/sup〉 s〈sup〉−1〈/sup〉 and is 4.7 ± 0.5 × 10〈sup〉13〈/sup〉 s〈sup〉−1〈/sup〉 were obtained for proton and deuteron transmission respectively across graphene. These pre-factor values are both quite large, on the order of the values predicted from the Eyring – Polanyi equation with a transmission coefficient near one. The ratio of 1.8 for the rate pre-factors (H/D) is in reasonable agreement with the value of 1.3 for the ratio of bond vibrational frequencies for O〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉H and O-D stretching, respectively. Taken together, these data support a model in which proton and deuteron transmission across graphene are largely adiabatic processes for which the differences in transmission rate at room temperature are due largely to differences in activation energies.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Molecular Phylogenetics and Evolution, Volume 131〈/p〉 〈p〉Author(s): P.V. Bruyns, P. Hanáček, C. Klak〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The Crassulaceae is an important family in the Greater Cape Floristic Region of southern Africa and is the seventh largest family in the arid Succulent Karoo Biome. After the Aizoaceae it is the largest group of leaf-succulents in southern Africa.〈/p〉 〈p〉This is the first investigation of a broad selection (68%) of the ±170 species of 〈em〉Crassula〈/em〉. We used data from three chloroplast and two nuclear gene-regions, which yielded many informative characters and provided good resolution among the species.〈/p〉 〈p〉We show that only five of the 20 sections in 〈em〉Crassula〈/em〉 are monophyletic. However, the clades recovered show close correlation with the two subgenera that were once recognized. 〈em〉Crassula〈/em〉 contains more than 25 succulent annual species which are not closely related to each other but form early-diverging branches in each of the three major clades. One of these major clades contains far more perennial species than the others and is the greatest diversification within 〈em〉Crassula〈/em〉. This diversification mostly arose within the last 10 million years (my) and spread across much of southern Africa. Members of the smaller two major clades are often soft- and flat-leaved perennials (many with basic chromosome number x = 8, with high levels of polyploidy). Those in the largest diversification (where a basic chromosome number of x = 7 predominates) show other arid-adaptations (more highly succulent leaves with a dense covering of hairs or papillae or a smooth xeromorphic epidermis). Their flowers are also more variable in shape and bee-, moth- and butterfly-pollinated species are known among them.〈/p〉 〈p〉We establish that 〈em〉Crassula〈/em〉 arose in the Greater Cape Floristic Region of southern Africa. While much of its diversity has evolved in the last 10 my, 〈em〉Crassula〈/em〉 nevertheless contains species that are much older and itself arose ±46 my ago. Since all its species are succulent it is possible that they are part of an early arid-adapted flora that contributed to the Succulent Karoo Biome in the western part of southern Africa. Consequently this Biome may not be assembled only from ‘young lineages’ as is usually thought to be the case.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1055790318303567-ga1.jpg" width="104" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 7 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Theoretical Biology, Volume 462〈/p〉 〈p〉Author(s): Rani Anupama, Sajitha Lulu, Rout Madhusmita, Sundararajan Vino, Amitava Mukherjee, Subramanian Babu〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉Pseudomonas aeruginosa〈/em〉 is a pathogenic biofilm forming bacteria which exist in wide range of environments such as water, soil and human body. In an earlier study, we used a system biology approach based analysis of biofilm forming genes of 〈em〉P. aeruginosa〈/em〉 and their possible role in TiO〈sub〉2〈/sub〉 nanoparticle binding. The major protein of 〈em〉P. aeruginosa〈/em〉 targeted by TiO〈sub〉2〈/sub〉 was found to be KatA, a major catalase required for H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 resistance and acute virulence and the direct interacting protein partners of KatA were found to be DnaK, Hfq, RpoA and RpoS. To understand the protein-protein physical interaction characteristic of these key proteins involved in biofilm related processes, homology modeling, docking and molecular dynamic simulation were performed. For all these proteins, physical and chemical properties, amino acid composition, nest and cleft analysis were performed using online tools. The interactions between TiO〈sub〉2〈/sub〉NPs–KatA and four protein–protein complexes such as KatA–DnaK, KatA–Hfq, KatA–RpoA and KatA–RpoS were studied. Our results indicate that all four key proteins and TiO〈sub〉2〈/sub〉NPs can have stable complexation with KatA. The study has given enough clues to understand the interaction of TiO〈sub〉2〈/sub〉NPs with 〈em〉P. aeruginosa〈/em〉 biofilm in natural environment. Further investigations could lead to development of TiO〈sub〉2〈/sub〉NPs based therapeutic and sanitary interventions to combat this pathogenic bacterium.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Molecular Cell, Volume 72, Issue 3〈/p〉 〈p〉Author(s): Lorea Blazquez, Warren Emmett, Rupert Faraway, Jose Mario Bello Pineda, Simon Bajew, Andre Gohr, Nejc Haberman, Christopher R. Sibley, Robert K. Bradley, Manuel Irimia, Jernej Ule〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Recursive splicing (RS) starts by defining an “RS-exon,” which is then spliced to the preceding exon, thus creating a recursive 5′ splice site (RS-5ss). Previous studies focused on cryptic RS-exons, and now we find that the exon junction complex (EJC) represses RS of hundreds of annotated, mainly constitutive RS-exons. The core EJC factors, and the peripheral factors PNN and RNPS1, maintain RS-exon inclusion by repressing spliceosomal assembly on RS-5ss. The EJC also blocks 5ss located near exon-exon junctions, thus repressing inclusion of cryptic microexons. The prevalence of annotated RS-exons is high in deuterostomes, while the cryptic RS-exons are more prevalent in 〈em〉Drosophila〈/em〉, where EJC appears less capable of repressing RS. Notably, incomplete repression of RS also contributes to physiological alternative splicing of several human RS-exons. Finally, haploinsufficiency of the EJC factor 〈em〉Magoh〈/em〉 in mice is associated with skipping of RS-exons in the brain, with relevance to the microcephaly phenotype and human diseases.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1097276518308323-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Molecular Cell, Volume 72, Issue 3〈/p〉 〈p〉Author(s): Jodi Bubenik, Maurice S. Swanson〈/p〉 〈div〉〈p〉In this issue of 〈em〉Molecular Cell〈/em〉, Yap et al. (2018) identify a novel lncRNA (PNCTR) that contains short tandem repeats that trap the RNA splicing factor PTBP1 in the perinucleolar compartment and link this sequestration activity to cancer cell development.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Molecular Cell, Volume 72, Issue 3〈/p〉 〈p〉Author(s): Timothy R. Abbott, Lei S. Qi〈/p〉 〈div〉〈p〉In a recent issue of 〈em〉Nature〈/em〉, Halperin et al. (2018) develop a new technology to continuously diversify specific genomic loci by combining CRISPR-Cas9 with error-prone DNA polymerases.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Molecular Cell, Volume 72, Issue 4〈/p〉 〈p〉Author(s): Sandro Baldi, Dhawal S. Jain, Lisa Harpprecht, Angelika Zabel, Marion Scheibe, Falk Butter, Tobias Straub, Peter B. Becker〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Regular successions of positioned nucleosomes, or phased nucleosome arrays (PNAs), are predominantly known from transcriptional start sites (TSSs). It is unclear whether PNAs occur elsewhere in the genome. To generate a comprehensive inventory of PNAs for 〈em〉Drosophila〈/em〉, we applied spectral analysis to nucleosome maps and identified thousands of PNAs throughout the genome. About half of them are not near TSSs and are strongly enriched for an uncharacterized sequence motif. Through genome-wide reconstitution of physiological chromatin in 〈em〉Drosophila〈/em〉 embryo extracts, we uncovered the molecular basis of PNA formation. We identified Phaser, an unstudied zinc finger protein that positions nucleosomes flanking the motif. It also revealed how the global activity of the chromatin remodelers CHRAC/ACF, together with local barrier elements, generates islands of regular phasing throughout the genome. Our work demonstrates the potential of chromatin assembly by embryo extracts as a powerful tool to reconstitute chromatin features on a global scale 〈em〉in vitro〈/em〉.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1097276518308037-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Molecular Cell, Volume 72, Issue 3〈/p〉 〈p〉Author(s): Thomas Gonatopoulos-Pournatzis, Mingkun Wu, Ulrich Braunschweig, Jonathan Roth, Hong Han, Andrew J. Best, Bushra Raj, Michael Aregger, Dave O’Hanlon, Jonathan D. Ellis, John A. Calarco, Jason Moffat, Anne-Claude Gingras, Benjamin J. Blencowe〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Alternative splicing is crucial for diverse cellular, developmental, and pathological processes. However, the full networks of factors that control individual splicing events are not known. Here, we describe a CRISPR-based strategy for the genome-wide elucidation of pathways that control splicing and apply it to microexons with important functions in nervous system development and that are commonly misregulated in autism. Approximately 200 genes associated with functionally diverse regulatory layers and enriched in genetic links to autism control neuronal microexons. Remarkably, the widely expressed RNA binding proteins Srsf11 and Rnps1 directly, preferentially, and frequently co-activate these microexons. These factors form critical interactions with the neuronal splicing regulator Srrm4 and a bi-partite intronic splicing enhancer element to promote spliceosome formation. Our study thus presents a versatile system for the identification of entire splicing regulatory pathways and further reveals a common mechanism for the definition of neuronal microexons that is disrupted in autism.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1097276518308402-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 European Polymer Journal〈/p〉 〈p〉Author(s): Ali Behnood, Mahsa Modiri Gharehveran〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Asphalt binders play an integral role in the performance and properties of asphalt mixtures. Increased traffic-related factors on the roadways such as heavier loads, higher traffic volume, and higher tire pressure combined with substantial variation in daily and seasonal temperatures of the pavement have been responsible for the asphalt pavements failure. To prevent or mitigate these failures, many attempts have been made by polymer scientists and civil engineers to improve the performance of asphalt pavements by modifying the properties of asphalt binders. A good modifier changes the failure properties such that binder yields more stresses and strains before failure. Modification of asphalt binders through the addition of a polymer to improve their rheological and physical properties has a long history in asphalt industry. Once the polymer is properly mixed with the asphalt binder, a swallowed polymer network is formed, which contributes to the changes in viscoelastic behavior. However, polymer-modified asphalt binders may have some drawbacks related to the poor solubility of polymers. Understanding the internal structure of polymer-modified asphalt binders has been the subject of numerous research studies.〈/p〉 〈p〉Available studies regarding the affecting parameters on the properties of the polymer-modified asphalt binders are reviewed here. Various types of polymers used in asphalt industry and their effects on the rheological, morphological, physical and mechanical properties of polymer-modified asphalt binders are also discussed in this paper. In addition, this paper provides a review on the techniques used to overcome/mitigate the shortcomings of conventional polymer-modified asphalt binders.〈/p〉 〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0014305718318019-ga1.jpg" width="341" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 19 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Neuron, Volume 100, Issue 6〈/p〉 〈p〉Author(s): Giacomo Benvenuti, Yuzhi Chen, Charu Ramakrishnan, Karl Deisseroth, Wilson S. Geisler, Eyal Seidemann〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Humans have remarkable scale-invariant visual capabilities. For example, our orientation discrimination sensitivity is largely constant over more than two orders of magnitude of variations in stimulus spatial frequency (SF). Orientation-selective V1 neurons are likely to contribute to orientation discrimination. However, because at any V1 location neurons have a limited range of receptive field (RF) sizes, we predict that at low SFs V1 neurons will carry little orientation information. If this were the case, what could account for the high behavioral sensitivity at low SFs? Using optical imaging in behaving macaques, we show that, as predicted, V1 orientation-tuned responses drop rapidly with decreasing SF. However, we reveal a surprising coarse-scale signal that corresponds to the projection of the luminance layout of low-SF stimuli to V1’s retinotopic map. This homeomorphic and distributed representation, which carries high-quality orientation information, is likely to contribute to our striking scale-invariant visual capabilities.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 19 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Current Biology, Volume 28, Issue 22〈/p〉 〈p〉Author(s): Ignacio E. Schor, Giovanni Bussotti, Matilda Maleš, Mattia Forneris, Rebecca R. Viales, Anton J. Enright, Eileen E.M. Furlong〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Long non-coding RNAs (lncRNAs) can often function in the regulation of gene expression during development; however, their generality as essential regulators in developmental processes and organismal phenotypes remains unclear. Here, we performed a tailored investigation of lncRNA expression and function during 〈em〉Drosophila〈/em〉 embryogenesis, interrogating multiple stages, tissue specificity, nuclear localization, and genetic backgrounds. Our results almost double the number of annotated lncRNAs expressed at these embryonic stages. lncRNA levels are generally positively correlated with those of their neighboring genes, with little evidence of transcriptional interference. Using fluorescent 〈em〉in situ〈/em〉 hybridization, we report the spatiotemporal expression of 15 new lncRNAs, revealing very dynamic tissue-specific patterns. Despite this, deletion of selected lncRNA genes had no obvious developmental defects or effects on viability under standard and stressed conditions. However, two lncRNA deletions resulted in modest expression changes of a small number of genes, suggesting that they fine-tune expression of non-essential genes. Several lncRNAs have strain-specific expression, indicating that they are not fixed within the population. This intra-species variation across genetic backgrounds may thereby be a useful tool to distinguish rapidly evolving lncRNAs with as yet non-essential roles.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Neuron, Volume 100, Issue 5〈/p〉 〈p〉Author(s): Brian E. Kalmbach, Anatoly Buchin, Brian Long, Jennie Close, Anirban Nandi, Jeremy A. Miller, Trygve E. Bakken, Rebecca D. Hodge, Peter Chong, Rebecca de Frates, Kael Dai, Zoe Maltzer, Philip R. Nicovich, C. Dirk Keene, Daniel L. Silbergeld, Ryder P. Gwinn, Charles Cobbs, Andrew L. Ko, Jeffrey G. Ojemann, Christof Koch〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Gene expression studies suggest that differential ion channel expression contributes to differences in rodent versus human neuronal physiology. We tested whether h-channels more prominently contribute to the physiological properties of human compared to mouse supragranular pyramidal neurons. Single-cell/nucleus RNA sequencing revealed ubiquitous 〈em〉HCN1〈/em〉-subunit expression in excitatory neurons in human, but not mouse, supragranular layers. Using patch-clamp recordings, we found stronger h-channel-related membrane properties in supragranular pyramidal neurons in human temporal cortex, compared to mouse supragranular pyramidal neurons in temporal association area. The magnitude of these differences depended upon cortical depth and was largest in pyramidal neurons in deep L3. Additionally, pharmacologically blocking h-channels produced a larger change in membrane properties in human compared to mouse neurons. Finally, using biophysical modeling, we provide evidence that h-channels promote the transfer of theta frequencies from dendrite-to-soma in human L3 pyramidal neurons. Thus, h-channels contribute to between-species differences in a fundamental neuronal property.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 19 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Current Biology, Volume 28, Issue 22〈/p〉 〈p〉Author(s): Zhenli Huang, Luhai Wang〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Dams are considered to be a serious threat to migratory fish on a global scale. Most of the world's rivers have been dammed, including those containing hotspots of fish diversity [1, 2, 3]. The mechanism by which dams affect fish is unclear and has often led to an underestimation of their cumulative and far-reaching adverse effects. Remedial measures of fish rescue for existing dams, including fish passage facilities and restocking, are insufficient or inefficient [1]. Although small and old dams are increasingly being removed, it is clearly unrealistic to demolish large, multi-section dams [4]. Hence, designing environmental flow to rescue fish is a complex challenge [5] and requires an in-depth understanding of the mechanism. Here, we propose an essential theory to reveal the relationship between dams and fish and discover novel insights into the migration behaviors, gonadal degeneration, and population dynamics of the Chinese sturgeon. We show that since 1981, the Gezhouba Dam has reduced the migration distance by 1,175 km, resulting in gonadal development being delayed by 37 days, resulting in the effective breeding population size and environmental capacity of the new spawning ground respectively reduced to 24.1% and 6.5% of the original. Even worse, subsequently built dams, particularly the Three Gorges Dam and Xiluodu Dam, have further reduced the effective breeding quantity to 0%–4.5% by elevating the water temperature to inhibit breeding activity during the breeding season. The cumulative effect of the cascade dams has led to an ongoing decline in adult abundances in the Yangtze River and the sea.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0960982218312272-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 The American Journal of Human Genetics, Volume 103, Issue 5〈/p〉 〈p〉Author(s): Serge Bonnefoy, Christopher M. Watson, Kristin D. Kernohan, Moara Lemos, Sebastian Hutchinson, James A. Poulter, Laura A. Crinnion, Ian Berry, Jennifer Simmonds, Pradeep Vasudevan, Chris O’Callaghan, Robert A. Hirst, Andrew Rutman, Lijia Huang, Taila Hartley, David Grynspan, Eduardo Moya, Chunmei Li, Ian M. Carr, David T. Bonthron〈/p〉 〈div〉〈p〉Primary defects in motile cilia result in dysfunction of the apparatus responsible for generating fluid flows. Defects in these mechanisms underlie disorders characterized by poor mucus clearance, resulting in susceptibility to chronic recurrent respiratory infections, often associated with infertility; laterality defects occur in about 50% of such individuals. Here we report biallelic variants in 〈em〉LRRC56〈/em〉 (known as 〈em〉oda8〈/em〉 in 〈em〉Chlamydomonas〈/em〉) identified in three unrelated families. The phenotype comprises laterality defects and chronic pulmonary infections. High-speed video microscopy of cultured epithelial cells from an affected individual showed severely dyskinetic cilia but no obvious ultra-structural abnormalities on routine transmission electron microscopy (TEM). Further investigation revealed that LRRC56 interacts with the intraflagellar transport (IFT) protein IFT88. The link with IFT was interrogated in 〈em〉Trypanosoma brucei.〈/em〉 In this protist, LRRC56 is recruited to the cilium during axoneme construction, where it co-localizes with IFT trains and is required for the addition of dynein arms to the distal end of the flagellum. In 〈em〉T. brucei〈/em〉 carrying 〈em〉LRRC56〈/em〉-null mutations, or a variant resulting in the p.Leu259Pro substitution corresponding to the p.Leu140Pro variant seen in one of the affected families, we observed abnormal ciliary beat patterns and an absence of outer dynein arms restricted to the distal portion of the axoneme. Together, our findings confirm that deleterious variants in 〈em〉LRRC56〈/em〉 result in a human disease and suggest that this protein has a likely role in dynein transport during cilia assembly that is evolutionarily important for cilia motility.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 19 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Current Biology, Volume 28, Issue 22〈/p〉 〈p〉Author(s): Johannes Larsch, Herwig Baier〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Collective behavior, such as shoaling in teleost fish, is driven by the perceptual recognition of conspecific animals. Because social interactions are mutual, it has been difficult to disentangle the exact sensory cues that trigger affiliation in the first place from those that are emitted by receptive and responsive shoal mates. Here, we overcome this challenge in a virtual reality assay in zebrafish. We discovered that simple visual features of conspecific biological motion provide a potent shoaling cue. Individual juvenile fish shoal for hours with circular black dots projected onto a screen, provided these virtual objects mimic the characteristic kinetics of zebrafish swim bouts. Other naturalistic cues previously implicated in shoaling, such as fish-like shape, pigmentation pattern, or non-visual sensory modalities are not required. During growth, the animals’ stimulus preferences shift gradually, matching self-like kinetics, and this tuning exists even in fish raised in isolation. Virtual group interactions and our multi-agent model implementation of this perceptual mechanism demonstrate that kinetic cues can drive assortative shoaling, a phenomenon commonly observed in field studies. Coordinated behavior can emerge from autonomous interactions, such as collective odor avoidance in 〈em〉Drosophila〈/em〉, or from reciprocal interactions, such as the codified turn-taking in wren duet singing. We found that individual zebrafish shoal autonomously without evidence for a reciprocal choreography. Our results reveal individual-level, innate perceptual rules of engagement in mutual affiliation and provide experimental access to the neural mechanisms of social recognition.〈/p〉〈/div〉 〈div〉 〈h6〉Video Abstract〈/h6〉 〈p〉〈/p〉 〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0960982218312090-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of the Mechanics and Physics of Solids, Volume 122〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Marine Policy, Volume 99〈/p〉 〈p〉Author(s): Pablo Quero García, Javier García Sanabria, Juan Adolfo Chica Ruiz〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years the European Union has firmly committed itself to energy from oceans as a means of decarbonising the European energy system. Despite a favourable political landscape, the development of offshore renewables still faces economic and technological barriers, which are coupled with the inherent difficulties of an increasingly industrialised marine environment, such as complex evolving regulation, lack of knowledge regarding the possible environmental impact of such an activity, as well as spatial conflicts with other traditional and emerging uses. Most of the coastal Member States have adopted Maritime Spatial Planning (MSP) as a fundamental tool for integrated and sustainable management of human activities in the marine environment. MSP is capable of definitively driving the use of offshore renewable facilities. Its proper application supports decision making, simplifies and accelerates the process of obtaining permits, improves compatibility of uses, integrates stakeholders in planning, prevents environmental deterioration of sensitive areas, enhances the availability of information and promotes cross-border co-operation. This paper aims to evaluate the influence of maritime spatial planning processes on the advance of blue energy within the framework of the European Union. The results show positive relationships between MSP and the development of offshore renewable energy in countries such as Germany, the Netherlands and the United Kingdom.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0308597X1830304X-fx1.jpg" width="477" alt="fx1" title="fx1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Ocean & Coastal Management, Volume 167〈/p〉 〈p〉Author(s): Uxío Labarta, M〈sup〉a〈/sup〉 José Fernández-Reiriz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The mussels industry with a production that accounts for more than twenty five percent of the fresh product landings from the sea, and the full-time employment of more than 8000 people, is by far the largest productive activity of the Galician sea.〈/p〉 〈p〉In the 1980s was noticed an increase in productivity related to processes of innovation in the industry of mussel. Together with it, the first organizational forms of the Galician-based production sector was constituted, with a spatial and administrative reordering for mussel rafts and crops. A new reality of the sector was maintained in both the marketing guidelines and the fact of initiating a vertical integration between the mussel industry and the commercialization. Everything was accompanied by changes in markets and strong tensions: derived from red tides that limit the operating cycle and even its profitability and also from the conflicts between the producing and transforming organizations, added to the competition in the markets of other countries, mainly Chile.〈/p〉 〈p〉The reality of mussel culture and markets leads to a reformulation in the industry, with strategies for territorial diversification of suppliers, new technological improvements in production and even organizational, economic, and bioecological innovations.〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Electrochimica Acta, Volume 295〈/p〉 〈p〉Author(s): Kaili Jin, Man Zhou, Hong Zhao, Shixiong Zhai, Fengyan Ge, Yaping Zhao, Zaisheng Cai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the large theoretical capacity and environmental benignity, copper sulfide (CuS) becomes a prospective candidate electrode material for supercapacitors. In this work, electroconductive mesoporous carbonized clothes (Cc) was obtained by carbonizing the waste cotton fabrics. Then the CuS was galvanostatic electrodeposited on 〈em〉Cc〈/em〉 to prepare the binder-free 〈em〉g〈/em〉-CuS/Cc electrode. In the galvanostatic electrodeposition process, CuS grew along the crystal surface to form regular nanosheets, and a part of Cu〈sup〉2+〈/sup〉 were reduced to Cu〈sup〉1.1+〈/sup〉. In addition, on account of the synergistic effect of electrochemical double layer capacitance with pseudocapacitance and the high specific surface area (450.76 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉), the 〈em〉g〈/em〉-CuS/Cc composite displayed not only outstanding areal specific capacitance (4676 mF cm〈sup〉−2〈/sup〉 at 2 mA cm〈sup〉−2〈/sup〉) but also excellent cycling performance (89.8% retention after 10000 cycles). Meanwhile, the symmetrical flexible supercapacitor (SC) based on 〈em〉g〈/em〉-CuS/Cc electrodes with PVA-KOH gel electrolyte (〈em〉g〈/em〉-CuS/Cc-SC) accomplished a high specific capacitance of 1333 mF cm〈sup〉−2〈/sup〉 at 2 mA cm〈sup〉−2〈/sup〉 as well as ultrahigh energy density of 0.96 Wh cm〈sup〉−2〈/sup〉 at the power density of 4.36 W cm〈sup〉−2〈/sup〉. Therefore, 〈em〉g〈/em〉-CuS/Cc shows a great potential for applications in the next generation of flexible energy storage devices.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0013468618324447-fx1.jpg" width="384" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Electrochimica Acta, Volume 295〈/p〉 〈p〉Author(s): Kang Li, Zhanwei Xu, Xuetao Shen, Kai Yao, Jianshe Zhao, Ronglan Zhang, Jun Zhang, Li Wang, Jianfeng Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Commercial lithium/thionyl chloride (Li/SOCl〈sub〉2〈/sub〉) batteries cannot meet the 3.15 V platform required for most instruments. A 〈em〉hovenia acerba〈/em〉-like assembly constructed with cobalt tetrapyridinoporphyrazine of thickness of 5–15 nm is anchored on acid-functionalized multi-walled carbon nanotubes (CoTAP/MWCNTs), which were prepared using an 〈em〉in situ〈/em〉 solid synthesis process. The discharge time of Li/SOCl〈sub〉2〈/sub〉 batteries with a voltage greater than 3.15 V catalyzed by CoTAP/MWCNTs is found to be 11 min longer than batteries without catalysts and 4 min longer than those catalyzed by CoTAP alone. The energy of Li/SOCl〈sub〉2〈/sub〉 batteries with a voltage greater than 3.15 V catalyzed by CoTAP/MWCNTs is discovered to be 11.44-times higher than batteries with AF-MWCNTs and 6.17-times higher than those catalyzed by bulk CoTAP. This is due to the fact that more CoTAP ultrafine nanoparticulates are anchored on the AF-MWCNTs. These nanoparticulates provide more active sites for the catalytic reaction of SOCl〈sub〉2〈/sub〉. The assemblies are shown to have an adsorption-coordination effect on Li ions and to delay the deposition of lithium chloride passive films enhancing battery voltage platforms.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉A 〈em〉hovenia acerba〈/em〉-like assembly constructed with cobalt tetrapyridinoporphyrazine of thickness of 5–15 nm is anchored on acid-functionalized multi-walled carbon nanotubes (CoTAP/MWCNTs), which were prepared using an 〈em〉in situ〈/em〉 solid synthesis process. The discharge time of Li/SOCl〈sub〉2〈/sub〉 batteries with a voltage greater than 3.15 V catalyzed by CoTAP/MWCNTs is found to be 11 min longer than batteries without catalysts and 4 min longer than those catalyzed by CoTAP alone.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0013468618324319-fx1.jpg" width="270" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Marine Policy, Volume 99〈/p〉 〈p〉Author(s): Bong-Tae Kim, Christopher L. Brown, Do-Hoon Kim〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We assess the vulnerability to climate change of Korean aquaculture based on predicted changes in seawater temperature and salinity in adjacent sea areas of the Korean Peninsula according to representative concentration pathways (RCP) scenarios. Unlike previous studies that have been conducted mostly on a national scale, we classify 14 farming species in major production regions of the Republic of Korea, and assess their vulnerability for each region, using the indicator-based method and the Intergovernmental Panel on Climate Change's definition of vulnerability in order to overcome limitations in developing specific adaptation strategies within a country. First, for each exposure, sensitivity, and adaptive capacity, specific and proper indicators are selected. Subsequently, these indicators are estimated and weighted to analyze vulnerability to climate change. The results show that the absolute level of vulnerability is high in a long-term period of RCP8.5 in which exposure becomes severe, whereas the relative vulnerability is similar among farming species and regions. Specifically, vulnerability is at the highest level in seaweed, such as laver and sea mustard, while fish, shrimp, and abalone are relatively less vulnerable to climate change.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 13 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Cell, Volume 175, Issue 7〈/p〉 〈p〉Author(s): Zheng Shi, Zachary T. Graber, Tobias Baumgart, Howard A. Stone, Adam E. Cohen〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉The fluid-mosaic model posits a liquid-like plasma membrane, which can flow in response to tension gradients. It is widely assumed that membrane flow transmits local changes in membrane tension across the cell in milliseconds, mediating long-range signaling. Here, we show that propagation of membrane tension occurs quickly in cell-attached blebs but is largely suppressed in intact cells. The failure of tension to propagate in cells is explained by a fluid dynamical model that incorporates the flow resistance from cytoskeleton-bound transmembrane proteins. Perturbations to tension propagate diffusively, with a diffusion coefficient 〈em〉D〈/em〉〈sub〉σ〈/sub〉 ∼0.024 μm〈sup〉2〈/sup〉/s in HeLa cells. In primary endothelial cells, local increases in membrane tension lead only to local activation of mechanosensitive ion channels and to local vesicle fusion. Thus, membrane tension is not a mediator of long-range intracellular signaling, but local variations in tension mediate distinct processes in sub-cellular domains.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0092867418313059-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): X.Y. Wang, S.L. Zhang, S.D. Feng, L. Qi, R.P. Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The structures of the Ti〈sub〉75〈/sub〉Al〈sub〉25〈/sub〉 alloy during rapid-quenching with and without external pressure are investigated by using molecular dynamic techniques. The amorphous phase can be obtained at the cooling rate 10.0 K/ps without pressure. The alloy is composed of crystal and amorphous phase at the cooling rate 0.1 and 1.0 K/ps without pressure, but the pure amorphous phase can be formed when the pressure exceeds the critical value. The critical pressure is about 20 and 30 GPa when the cooling rate is 0.1 and 1.0 K/ps, respectively. H-A indices analysis indicates that high pressure favors the formation of the ideal icosahedral structures in the amorphous Ti〈sub〉75〈/sub〉Al〈sub〉25〈/sub〉 alloy, and the content of 1551 bond-type can reach near to 50% when the pressure is 30 GPa. The amorphous state can be maintained if the external pressure is removed from the alloy step-by-step. The content of 1551 bond-type decreases with the deceasing of the pressure, but the 1541 and 1431 bond-types increase in this process.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Physics and Chemistry of Solids, Volume 124〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Cell, Volume 175, Issue 4〈/p〉 〈p〉Author(s): Moshe Sade-Feldman, Keren Yizhak, Stacey L. Bjorgaard, John P. Ray, Carl G. de Boer, Russell W. Jenkins, David J. Lieb, Jonathan H. Chen, Dennie T. Frederick, Michal Barzily-Rokni, Samuel S. Freeman, Alexandre Reuben, Paul J. Hoover, Alexandra-Chloé Villani, Elena Ivanova, Andrew Portell, Patrick H. Lizotte, Amir R. Aref, Jean-Pierre Eliane, Marc R. Hammond〈/p〉 〈h5〉Summary〈/h5〉 〈div〉〈p〉Treatment of cancer has been revolutionized by immune checkpoint blockade therapies. Despite the high rate of response in advanced melanoma, the majority of patients succumb to disease. To identify factors associated with success or failure of checkpoint therapy, we profiled transcriptomes of 16,291 individual immune cells from 48 tumor samples of melanoma patients treated with checkpoint inhibitors. Two distinct states of CD8〈sup〉+〈/sup〉 T cells were defined by clustering and associated with patient tumor regression or progression. A single transcription factor, 〈em〉TCF7〈/em〉, was visualized within CD8〈sup〉+〈/sup〉 T cells in fixed tumor samples and predicted positive clinical outcome in an independent cohort of checkpoint-treated patients. We delineated the epigenetic landscape and clonality of these T cell states and demonstrated enhanced antitumor immunity by targeting novel combinations of factors in exhausted cells. Our study of immune cell transcriptomes from tumors demonstrates a strategy for identifying predictors, mechanisms, and targets for enhancing checkpoint immunotherapy.〈/p〉〈/div〉 〈h5〉Graphical Abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0092867418313941-fx1.jpg" width="375" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Surface Science, Volumes 467–468〈/p〉 〈p〉Author(s): S.P. Sun, J.L. Zhu, S. Gu, X.P. Li, W.N. Lei, Y. Jiang, D.Q. Yi, G.H. Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The surface stability and equilibrium morphology of MoO〈sub〉3〈/sub〉 were investigated by the first principles calculations. The thermodynamic energies of the stoichiometric surfaces of MoO〈sub〉3〈/sub〉 are in the order (0 1 0) 〈 (1 0 1) 〈 (0 0 1) 〈 (1 0 0). It is found that the (0 1 0) surface has a lowest surface energy, which agrees well with the previous calculations. The energies of the non-stoichiometric surfaces were evaluated as functions of temperature and oxygen partial pressure. The results show that the energies of Mo-terminated surfaces decrease with temperatures, and increase with oxygen partial pressures, while the energies of O-terminated surfaces show the opposite rule. The equilibrium morphology of MoO〈sub〉3〈/sub〉 was predicted by using the Gibbs-Wulff model, and then was compared with the other’s experiments and theoretical results.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Surface Science, Volumes 467–468〈/p〉 〈p〉Author(s): Sanju Gupta, Nicholas Dimakis〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interfacial interactions between transition metal oxides (vanadium oxide VO〈sub〉2〈/sub〉, vanadium pentoxide V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉, cobalt oxide CoO and Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉, manganese oxide MnO〈sub〉2〈/sub〉) and water adsorbates on graphene supports as solvated interfaces and influence of defects in graphene are studied using periodic density functional theory (DFT) calculations in view of their significance for applied electrochemistry. DFT complemented and synergized our experimental work. The optimized metal oxide adatom-graphene geometries identified the preferred adatom sites, whereas metal oxide-graphene strengths are correlated with the adatom distance from the graphene plane, the Metal-C overlap populations, and the adsorption energies. The presence of finite electronic density of states (DOS) near Fermi level and charge transfers between the adatom top layer and graphene supports reflect primarily covalent bonding nature. The presence of small orbital overlap integral of bonds between the s and p (and d) orbitals of the nearest carbon (graphene), carbon oxide (graphene oxide) and metal oxide atoms reveal localized orbital re-hybridization resulting in changes in DOS yielding high electrochemical activity. Moreover, for increased adatom coverage the extent of charge transfer reverses resulting in limited electroactivity. In fact, DFT calculations are corroborated with experimental findings, where graphene-based supports decorated with optimal mass loaded nanostructured Co〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 and MnO〈sub〉2〈/sub〉 (as well as V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉) were capable of delivering maximum specific energy storage capacity (C〈sub〉s〈/sub〉) 〉 550 F·g〈sup〉−1〈/sup〉 (Gupta et al. J. Mater. Res. 32, 301 (2017)) in contrast to higher or lower loading. The presence of defects in graphene materials results in new electronic states to endow unique functionalities that is not otherwise possible in the bulk and with adsorbed water molecules besides optimum C/O ratio in graphene oxide nanosheets that show redshift thus a decreasing bandgap and finite charge transfer from graphene to water molecules. The case examples studied in this work represent a first glimpse of what may become routine and integral step in materials design and discovery for alternative energy and sustainable environmental technologies.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Anne-Isabelle Bidegaray, Andrea Ceglia, Maria Rita Cicconi, Van-Thai Pham, Amandine Crabbé, El Amine Mernissi Cherigui, Karin Nys, Herman Terryn, Daniel R. Neuville, Stéphane Godet〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The analysis of iron, manganese and antimony in silicate glass is of great interest in chemistry, materials science, earth sciences and archaeological sciences. Yet, conclusions from different fields appear to be contradictory and many questions about redox reactions in glass remain. The purpose of this study is thus to discuss whether and how these multivalent elements interact in glass. Soda-lime silicate melts containing iron along with manganese and/or antimony have been analysed at different high temperatures under argon atmosphere. Using 〈em〉in-situ〈/em〉 XANES at the Fe K-edge, redox thermodynamics, kinetics and diffusivities have been assessed for the different compositions. The data obtained show that antimony is more efficient at oxidising iron compared to manganese at all temperatures. The oxidising power trend would thus be Sb 〉 Sb + Mn 〉 Mn. Furthermore, hypotheses on the formation of Fe-Mn complexes are also reported in glasses with stoichiometric proportions of iron and manganese. Based on the determination of redox diffusivities, it appears that presence of other multivalent elements does not significantly affect the iron redox mechanisms and that diffusivity is essentially controlled by the mobility of calcium.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Wentao Zhang, Feng He, Junlin Xie, Xiaoqing Liu, De Fang, Hu Yang, Zhihong Luo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glass ceramics from modified molten blast furnace (BF) slag were prepared. The crystallization behavior of the modified BF slag was characterized using differential thermal analysis (DTA), X-ray diffraction (XRD), and field emission scanning electron microscope (FESEM). The crystallization kinetics results indicated that the crystallization activation energy initially decreased and subsequently increased with increasing CaO/SiO〈sub〉2〈/sub〉. The crystallization temperature and the crystallization index (n) decreased from 916 to 867 °C, and 5.66–1.13, respectively. The crystallization mechanism transformed from bulk crystallization to surface crystallization. By XRD analyzing, Melilite was developed as the main crystal phase, and the transformation of crystal from akermanite to gehlenite was observed. The rapid surface crystallization was beneficial for maintaining the shape of glass ceramics. The complex replacement in melilite crystals resulted in the micro cracks in glass ceramics, therefore led to the decrease of flexural strength of glass ceramics〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): B.C. Jamalaiah〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different amounts of GeO〈sub〉2〈/sub〉 activated tellurite tungstate glasses were prepared by melt quenching technique. Thermal stability and glass forming ability were studied using differential scanning calorimetry. The chemical composition, homogeneity and amorphous nature of studied glasses were investigated. The phonon energy was estimated to be 721.34 cm〈sup〉−1〈/sup〉. Experimentally determined refractive indices were compared with those determined from optical band gap (E〈sub〉g〈/sub〉) and optical electronegativity (Δ〈em〉χ〈/em〉〈sup〉∗〈/sup〉). The dielectric constant (K) and electronic polarizability (α) were determined using refractive index value. The presence of disorder was estimated in terms of Urbach energy (E〈sub〉U〈/sub〉). The average electronegativity (〈em〉χ〈/em〉〈sub〉〈em〉ave〈/em〉〈/sub〉), oxide ion polarizability (〈em〉α〈/em〉〈sub〉〈em〉O〈/em〉〈/sub〉〈sup〉2−〈/sup〉) and covalent character (C〈sub〉cov〈/sub〉) were determined. The content of GeO〈sub〉2〈/sub〉 was optimized to be 10.0 mol% to design a novel host material for solid state lasers and fiber devices.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Chunhe Jiang, Kejiang Li, Jianliang Zhang, Qinghua Qin, Zhengjian Liu, Minmin Sun, Ziming Wang, Wang Liang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉SiO〈sub〉2〈/sub〉-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-CaO-MgO is the most significant slag system in the blast furnace ironmaking process and it is very important to investigate the microstructure and viscosity of the system. In this paper, molecular dynamics simulations were carried out to explore the effects of MgO/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 ratio on structure and properties of the system. Based on the self-diffusion coefficients, the viscosities were calculated by Einstein-Stokes equation and compared with the experimental value and the Factsage value. The results showed that with the increase of MgO/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 ratio, the stability of [SiO〈sub〉4〈/sub〉]〈sup〉4−〈/sup〉 and [AlO〈sub〉4〈/sub〉]〈sup〉5−〈/sup〉 tetrahedron became weaken and the relative proportions of bridge and non-bridge oxygen showed a decrease. And due to the increase of MgO, more Mg〈sup〉2+〈/sup〉 ions are used as network modifiers to reduce the degree of polymerization of the system, resulting in a decrease in the viscosity, which is consistent with experimental results. Finally, based on the present study, in the case of increasing Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 content of blast furnace slag, the fluidity of slag could be adjusted by controlling MgO/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 ratio, thereby providing a basis for stable operation of blast furnace ironmaking.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): A.I. Popov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The definition of glassy state presented by the authors of the article “The glassy state of matter: Its definition and ultimate fate” E. Zanotto and J. Mauro is considered. The importance of the contribution to the glassy state problem made in the article is emphasized. At the same time consideration of the glassy state as unstable state of matter causes definite objections. It is more correctly to consider the glassy state as metastable state of matter.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): M.G. Syamala Rao, M.A. Pacheco-Zuñiga, L.A. Garcia-Cerda, G. Gutiérrez-Heredia, J.A. Torres Ochoa, M.A. Quevedo López, R. Ramírez-Bon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we developed a novel inorganic-organic hybrid gate dielectric by combining zirconium and hafnium components to form zirconium hafnium oxide strongly linked with polymethyl methacrylate (ZrHfO〈sub〉2〈/sub〉-PMMA) and deposited at low temperature (200 °C) by sol-gel method. The obtained 108 nm thick, high-quality hybrid gate dielectric showed an exceptionally low surface roughness (0.9-nm), a low leakage current density (7.7 × 10〈sup〉−6〈/sup〉 A/cm〈sup〉2〈/sup〉) and reasonable dielectric properties such as gate capacitance along with dielectric constant (77 nF/cm〈sup〉2〈/sup〉 & 9.4 @1 kHz) respectively. To examine the ZrHfO〈sub〉2〈/sub〉-PMMA hybrid dielectric electrical properties we constructed thin-film transistors (TFTs) with room temperature r.f sputtered n-type metal oxide semiconductors, a-IGZO and ZnO, as active channels. The bottom gate fabricated a-IGZO TFTs driving at as low as below 6 V, with extracted field effect mobility of 2.45 cm〈sup〉2〈/sup〉/V. s, a low threshold voltage of 1.2 V with large ON/OFF current ratio 10〈sup〉7〈/sup〉 respectively. On the other hand, for comparison we employed ZnO TFTs by applying same hybrid dielectric system, the obtained parameters of bottom gate ZnO TFTs were good field effect saturation mobility of 12.8 cm〈sup〉2〈/sup〉/V. s, threshold voltage of 1.8 V and ON/OFF current ratio of 10〈sup〉3〈/sup〉.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Weidi Zhu, Mark Lockhart, Bruce Aitken, Sabyasachi Sen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The viscoelastic properties of supercooled As〈sub〉x〈/sub〉Se〈sub〉100-x〈/sub〉 (0 ≤ x ≤ 30) and As〈sub〉x〈/sub〉Se〈sub〉100-x-y〈/sub〉I〈sub〉y〈/sub〉 (x = 20, 30 and y = 10, 20) liquids are studied using oscillatory parallel plate rheometry. In addition to the α-relaxation process, the shear relaxation of liquids with selenium chains longer than ~ 3 atoms is also characterized by a low-frequency polymeric mode. The temporal decoupling of this low-frequency soft/floppy relaxation mode from that of the α-relaxation mode is a unique function of the average selenium chain length. The floppy mode abruptly vanishes for liquids with average chain lengths shorter than ~ 3 Se atoms, thus implying a dynamical rigidity transition. When taken together, these results indicate that, contrary to the conventional wisdom, the pertinent structural variable associated with such transition in the viscoelastic behavior is not the average coordination number but instead the intermediate-range structural elements such as the average selenium chain length.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): M.S.A. Mohd Saidi, S.K. Ghoshal, K. Hamzah, R. Arifin, M.F. Omar, M.K. Roslan, E.S. Sazali〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report the influence of silver (Ag) and titania (TiO〈sub〉2〈/sub〉) nanoparticles (ATNPs) co-embedment on the photoluminescence (PL) properties of dysprosium ions (Dy〈sup〉3+〈/sup〉) doped zinc-magnesium tellurite glass system prepared using conventional melt quenching method. Both up- and down- converted PL spectra of glasses revealed three emission bands located at 482 (blue: 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉15/2〈/sub〉), 574 (yellow: 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉13/2〈/sub〉) and 664 nm (weak red: 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉11/2〈/sub〉), where the band intensities were enhanced with the inclusion of ATNPs. Glasses with 0.2 mol% of ANPs and up to 0.3 mol% of TNPs disclosed highest PL intensity enhancement, which was majorly attributed to the ATNPs mediated localized surface plasmon resonance (LSPR) and large field enhancement (called hot spot) effects in the proximity of Dy〈sup〉3+〈/sup〉 ions. Absorption spectra of glasses displayed two plasmon bands characteristics of each type of nanoparticle. It was inferred that the superposition of localized SP modes from ATNPs could generate new hybridized modes (strong local field in the vicinity of Dy〈sup〉3+〈/sup〉 ions) shifted with respect to the single type of NPs resonance. HRTEM images showed the existence of both Ag and titania NPs inside the glass matrix. Glasses containing ATNPs exhibited anatase phase with (103) and (112) nanocrystalline lattice plane orientation. Proposed glass system may be useful for the development of solid state laser and photonic devices.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Magnetism and Magnetic Materials, Volume 474〈/p〉 〈p〉Author(s): Muhammad Arshad, M. Asghar, Muhammad Junaid, Muhammad Farooq Warsi, M. Naveed Rasheed, M. Hashim, M.A. Al-Maghrabi, Muhammad Azhar Khan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study Co-Ni co-doped nanocrystalline manganese ferrites were fabricated via co-precipitation method. The annealing of as prepared nanoferrites was done at 950 °C for 7 h. The powder X-ray diffraction (XRD) confirmed that all samples possessed cubic spinel structure. The crystallite size was determined by Scherrer’s equation that lies in the range of 27–35 nm. The spectral analysis confirmed bending and stretching of bonds at octahedral (B) and tetrahedral (A) sites. The spectral bands were shifted towards the longer wavelength side and these indicate the incorporation of dopants cations (Co-Ni). The magnetic parameters were measured from the M-H loops of nanoferrites. With the increase of Co-Ni contents, the saturation magnetization (Ms) increased up to x = 0.15 and then it decreased. The dielectric properties of all compositions were studied in 1 MHz–3 GHz range and were discussed in the light of Debye-type reduction phenomenon by following the Koop’s theory. The dielectric and magnetic behavior evaluation suggested that synthesized ferrites are suitable for microwave devices fabrication.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0304885318319127-ga1.jpg" width="282" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Infrared Physics & Technology, Volume 96〈/p〉 〈p〉Author(s): Chunyan Guo, Yaoyao Sun, Qingxuan Jia, Zhi Jiang, Dongwei Jiang, Guowei Wang, Yingqiang Xu, Tao Wang, Jinshou Tian, Zhaoxin Wu, Zhichuan Niu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A kind of wide spectrum infrared detectors based on InAs/GaSb type-II superlattices (T2SLs) operating from 0.5 μm to 5 μm wavelength range is reported. The materials were grown by Molecular Beam Epitaxy (MBE) on GaSb substrates. Diverse types and sizes microstructure are fabricated on the surface of the detector to form the photon traps (PTs) array. PTs decrease the reflectivity and increase the light absorption of epitaxial material. Compared with the planar mesa detectors without antireflection (AR) film, detectors with PTs array exhibits a high responsivity of 0.86 A/W at 1160 nm and maximum D* reaches to 10〈sup〉9〈/sup〉 cm Hz〈sup〉1/2〈/sup〉/W in visible wavelength. Also, the PTs processed on detector augment spectral response and QE in infrared wavelength. The peak responsivity of the detector with PTs is to 1.35 A/W and QE can exceed to 0.76 in the infrared wavelength. The infrared detector with PTs is attractive for numerous applications.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solid State Sciences, Volume 85〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solid State Sciences, Volume 85〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Solid State Sciences, Volume 85〈/p〉 〈p〉Author(s): 〈/p〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Biology and Biochemistry, Volume 128〈/p〉 〈p〉Author(s): J.M. Kranabetter〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Forest floor carbon (C) sequestration has been negatively correlated with manganese (Mn) availability, possibly due to reduced efficacy of Mn-peridoxase enzymes produced by Agaricomycete fungi. I examined a soil C and Mn dataset from a podzolization gradient, along with fungal sporocarp Mn concentrations, to potentially corroborate this finding. An inverse power relationship between soil C and soil Mn content across temperate rainforests was confirmed, which provides further evidence of a Mn bottleneck in C turnover. Average Mn concentrations of saprotrophic sporocarps were greater than those of ectomycorrhizal fungi, and displayed a similar inverse correlation with increasing soil C. The absence or limited effectiveness of select saprotrophic fungi across Mn-depleted forest soils may be one mechanism behind impeded turnover of recalcitrant organic matter.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Biology and Biochemistry, Volume 128〈/p〉 〈p〉Author(s): Charles R. Warren〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Phospholipids are isolated from crude lipid extracts by silica solid phase extraction (SPE), but for soils we don't know if phospholipids are the only fatty acid-based lipids present in the polar lipid fraction. Lipids extracted from three soils were fractionated with a silica SPE protocol commonly used for soils, with “neutrals” eluted by chloroform, “glycolipids” eluted by acetone, and “phospholipids” eluted by methanol. Fatty acid-based lipids were identified and quantified by liquid chromatography-mass spectrometry. Phospholipids were recovered in the methanol fraction, but this fraction also included betaine lipids. In two soils the methanol fraction was 3–6% betaine lipid while in one soil betaine lipids accounted for 48% of lipids in the methanol fraction. Clearly the fraction obtained by eluting lipids from silica with methanol is not purely phospholipid but can contain significant amounts of other polar lipids.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Surface Science, Volumes 467–468〈/p〉 〈p〉Author(s): Xu Wu, Yalin Feng, Yali Du, Xuezhen Liu, Chunlei Zou, Zhe Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉LDHs templates (marked as CoAl-MnO〈sub〉2〈/sub〉-LDH and CoMnAl-CO〈sub〉3〈/sub〉-LDH) were fabricated via ion-exchange/redox reaction and hexamethylenetetramine (HMT) hydrolysis methods respectively. CoMnAl mixed metal oxides (marked as MnO〈sub〉2〈/sub〉/CoAl-LDO and CoMnAl-LDO) from the as-prepared LDHs templates were novelly prepared and tested as low-temperature NH〈sub〉3〈/sub〉-SCR catalysts. Catalytic evaluation pronouncedly affirmed that the catalytic performances of the as-acquired catalysts were vulnerable to the preparation method of precursor template, where MnO〈sub〉2〈/sub〉/CoAl-LDO presented preferable DeNOx activity (over 90% NOx conversion), N〈sub〉2〈/sub〉 selectivity and SO〈sub〉2〈/sub〉 resistance in much broader working temperature window (90–300 °C) than CoMnAl-LDO. Multiple characterizations revealed that the excellent catalytic performance of the MnO〈sub〉2〈/sub〉/CoAl-LDO could be attributed to its higher specific surface area which could promote dispersion of abundant Mn〈sup〉4+〈/sup〉 and Co〈sup〉3+〈/sup〉 species, and resultantly afforded stronger redox ability and more acid sites. Moreover, dynamic calculation confirmed that the relatively lower activation energy on MnO〈sub〉2〈/sub〉/CoAl-LDO for low-temperature NH〈sub〉3〈/sub〉-SCR reaction should be closely related to the occurrence of a more rapid redox cycle and in agreement with the excellent DeNOx performance.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0169433218329702-ga1.jpg" width="413" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Surface Science, Volumes 467–468〈/p〉 〈p〉Author(s): Sandra Jendrzej, Leonard Gondecki, Jörg Debus, Henning Moldenhauer, Peter Tenberge, Stephan Barcikowski, Bilal Gökce〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The lubricant is a central element in the transmission design. It primarily separates the two contact partners through a pressure-induced solidification in the lubrication gap, thus enabling the operation of heavily loaded sliding-rolling contacts. On the one hand, the quality and properties of a lubricant depend on the base oils, which differ by their viscosity and process-technological parameters. The addition of particulate additives gives the lubricants further functional properties that are not contained in the base oil. In this study, the influence of laser-synthesized yttria-stabilized zirconia nano- or submicrometer spheres as dispersed functional elements in the lubricant is studied, and their impact on wear and fatigue on the tooth flank is investigated. The work includes systematic investigations on the influence of the particle’s shape and size by running tests on a FZG gear test rig. Finally, the potential of the laser-generated particles as a lubricant additive is evaluated in a first conclusion.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Nuclear Materials, Volume 513〈/p〉 〈p〉Author(s): Matic Pečovnik, Sabina Markelj, Anže Založnik, Thomas Schwarz-Selinger〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influence of grain size on deuterium transport and retention in tungsten was studied. For this purpose an experiment was carried out on three polycrystalline tungsten samples with different grain sizes and a single crystal sample with surface orientation 〈100〉. In order to increase deuterium retention and hence the sensitivity for detection, samples were first damaged by high energy W ions. After damaging, the samples were exposed to a flux of deuterium atoms at 600 K for 70 h. During the exposure the depth profile of the retained deuterium was measured by Nuclear Reaction Analysis using a 〈sup〉3〈/sup〉He ion beam. After the exposure the samples were also analysed by Thermal Desorption Spectroscopy. A clear difference in the time dependence of deuterium uptake was noticed between different samples. The experimental results were modeled using a rate-equation model. The influence of different grain size was modeled by changing the effective height of the potential barrier for deuterium atoms to enter into the bulk. We managed to successfully describe the transport of deuterium into the bulk of tungsten by reducing the potential barrier for samples with smaller grain sizes while the barrier for the sample with larger grain size was close to the value for the damaged single crystal sample.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022311518307256-fx1.jpg" width="256" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Nuclear Materials, Volume 513〈/p〉 〈p〉Author(s): P.A. Burr, E. Kardoulaki, R. Holmes, S.C. Middleburgh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The stability, diffusivity and clustering behaviour of defects in uranium diboride (UB〈sub〉2〈/sub〉) was investigated in light of the potential application as a burnable absorber in nuclear fuel. UB〈sub〉2〈/sub〉 was found to accommodate limited deviations from stoichiometry, which should be a consideration when manufacturing and operating the material. Self-diffusivity of both U and B was found to be sluggish (10〈sup〉−14〈/sup〉 cm〈sup〉2〈/sup〉/s for B and 10〈sup〉−19〈/sup〉 cm〈sup〉2〈/sup〉/s for U at 2000K) and highly anisotropic, with migration along the basal planes being orders of magnitude faster than 〈em〉c〈/em〉-axis migration. The anisotropy of defect migration (both interstitials and vacancies) is predicted to hinder recombination of defects produced by collision cascades, thus limiting the radiation tolerance of the material. Boron and uranium vacancies exhibit a drive to cluster. Boron vacancies in particular, which are mobile on basal planes, are predicted to cluster into strongly bound di-vacancy, which in turn are less mobile. These are then predicted to grow into larger two-dimensional vacancy clusters on the B plane, leading to anisotropic swelling. We provide an analytical expression to predict the stability of these clusters based on purely geometrical considerations. Finally, the accommodation of Li, He and Xe onto vacancy clusters was considered. Li appears to stabilise the structure upon U depletion, while the retention of He and Xe appears to rise with increasing B depletion, through the formation of vacancy clusters.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Physica B: Condensed Matter, Volume 554〈/p〉 〈p〉Author(s): D. Bessas, I. Kantor, D. Bourazani, K. Georgalas, N. Biniskos, L. Zhang, A.I. Dugulan, E. Syskakis〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bulk Sr〈sub〉2〈/sub〉PdO〈sub〉3〈/sub〉 was synthesized by a modified solid state reaction and a detailed characterization was carried out using both microscopic and macroscopic experimental techniques. Pd site exhibits an electric field gradient of 5.9(1) ⋅ 10〈sup〉17〈/sup〉 V/cm〈sup〉2〈/sup〉 due to the anisotropic local atomic configuration. A Curie - paramagnetic susceptibility indicating antiferromagnetic interactions superimposed to a core diamagnetic state is confirmed. A linear volume thermal expansion with a coefficient of 3.0(1) ⋅ 10〈sup〉−5〈/sup〉 K〈sup〉−1〈/sup〉 at room temperature is extracted. A collection of Einstein oscillators, with an Einstein temperature of about 115 K, is involved in the thermal transport. Large atomic displacements were observed in Sr vibrations. No Pd or Sr valence change is observed up to 900 K. A moderate anharmonicity is identified and quantified in a macroscopic Grüneisen parameter of 2.5(1) at room temperature. The electrical resistivity reveals a semiconducting behaviour. A systematic reduction in electrical resistivity and a change in the conduction mechanism is observed upon thermal cycling which indicates that a peculiar electronic mechanism is involved.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Phytochemistry, Volume 157〈/p〉 〈p〉Author(s): XingRong Peng, Lei Li, JinRun Dong, ShuangYang Lu, Jing Lu, XiaoNian Li, Lin Zhou, MingHua Qiu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Twelve previously undescribed lanostane-type triterpenoids, including three triterpenoids with a 〈em〉γ〈/em〉-lactone ring, namely applanlactones A‒C, four highly oxygenated lanostane triterpenoids, namely methyl applaniate A and applanoic acids B‒D, as well as five C21 nortriterpenoids, applanones A‒E were isolated from the fruiting bodies of 〈em〉Ganoderma applanatum〈/em〉 (Pers.) Pat.〈em〉.〈/em〉 Their structures were elucidated by 1D, 2D NMR and MS spectra, as well as X-ray crystallographic analyses. Meanwhile, applanlactone A, methyl applaniate A and applanoic acid B showed inhibitory effects for the proliferation of hepatic stellate cells (HSCs) induced by transforming growth factor-〈em〉β〈/em〉1 (TGF-〈em〉β〈/em〉1) 〈em〉in vitro〈/em〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Three polyoxygenated lanostane triterpenoids isolated from the fruiting bodies of 〈em〉Ganoderma applanatum〈/em〉 showed anti-liver fibrosis activities.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0031942218303352-fx1.jpg" width="369" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment〈/p〉 〈p〉Author(s): S. Monzani, A. Andreazza, M. Citterio, P. Fontana, M. Ianna, T. Lari, V. Liberali, F. Ragusa, C. Sbarra, A. Sidoti, A. Stabile〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Monochromatic X and gamma rays are a standard calibration tool for semiconductor detector. For finely segmented pixel detectors, like the ones foreseen for HL-LHC detector upgrades, the single pixel spectrum is affected by charge sharing across nearby pixels, due to diffusion and the finite range of photoelectrons, resulting in a low energy continuum below the photoelectric peak. In this paper a systematic simulation study will be presented. The shape of the transition between the photoelectric peak and the continuum is determined by diffusion and needs to be unfolded for a correct estimation of the energy resolution. Simulation results are compared with data collected with different high-resistivity CMOS devices with 50 × 250 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll" altimg="si1.gif"〉〈mi mathvariant="normal"〉μ〈/mi〉〈/math〉m〈sup〉2〈/sup〉 pixel size and photon energies between 13 and 60 keV. They show a good agreement, highlighting the potential usage of the whole single pixel spectrum to derive device characteristics.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): G. Gorni, M.J. Pascual, A. Caballero, J.J. Velázquez, J. Mosa, Y. Castro, A. Durán〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The crystallization mechanism of LaF〈sub〉3〈/sub〉 in sol-gel oxyfluoride glass-ceramics in the system SiO〈sub〉2〈/sub〉-LaF〈sub〉3〈/sub〉 has been studied using DTA, XRD, FTIR, HRTEM and NMR. Based on classical calculations of non-isothermal DTA curves involving Ozawas's plots, a diffusion-controlled process should be responsible for the fluorides crystallization similarly to that obtained for melt-quenching oxyfluoride glass-ceramics. Therefore, an increase of the crystal size and fraction is expected when increasing the time and/or temperature of the treatment. Nevertheless, XRD, FIR, HRTEM and NMR demonstrated that neither bigger crystals nor higher crystal fraction are obtained for treatment times longer than 1 min at 550 °C. However, further heat treatment causes that the structural order of the crystals is lost. On the other hand, typical fluorides crystallization temperatures (~300 °C) in sol-gel materials are much lower than T〈sub〉g〈/sub〉 of the matrix (~1130 °C) thus being very different to what observed for oxyfluoride glasses prepared by melt-quenching. The proposed crystallization mechanism is a fast process that occurs when crystallization temperature is reached. This behavior is explained as a chemical reaction from the xerogels, followed by the fast precipitation of the nanocrystals without energy barrier. The nanocrystals are unstable in the surrounding SiO〈sub〉2〈/sub〉 matrix for aging at crystallization or higher temperatures. These treatments lead to a dissolution process, favored by the compositional gradient between matrix and crystals, which drive the material to reach the equilibrium.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Jürn W.P. Schmelzer, Alexander S. Abyzov, Vladimir M. Fokin, Christoph Schick〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉General relations for the dependence of the thermodynamic driving force of crystallization and the specific interfacial energy melt-crystal of critical crystal clusters on temperature and pressure are derived. Its application to the analysis of experimental data on crystal nucleation seems to support at a first glance a proposal by Kauzmann on the existence of a pseudo-spinodal curve in melt-crystallization. Provided this assumption is true, Kauzmann temperature (and for pressure-induced nucleation, the Kauzmann pressure) cannot be reached by a metastable liquid due to intensive crystallization processes occurring in its vicinity. However, such suggestion cannot be retained taking into account the kinetic terms (diffusion coefficients, viscosity) in the expression for the nucleation rate. The absence of a pseudo-spinodal in melt-crystallization can be verified also in an alternative way by considering the characteristic time scales of crystallization and relaxation. Finally, it is shown that the phenomenon denoted commonly as Kauzmann paradox is merely an untypical as compared to normal conditions type of behavior. Neither in its original formulation nor in its consequences it results in any contradictions with basic laws of nature. They are prevented either by normal (not associated with a pseudo-spinodal) crystallization or a conventional glass transition.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): J. Gilabert, M.P. Gómez-Tena, V. Sanz, S. Mestre〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The effect of a post-synthesis thermal treatment on CoCr〈sub〉2−2Ψ〈/sub〉Al〈sub〉2Ψ〈/sub〉O〈sub〉4〈/sub〉 (0.0 ≤ Ψ ≤ 1.0) ceramic pigments synthesized by Solution Combustion Synthesis (SCS) has been studied. As-synthesized SCS pigments were treated at two different calcination temperatures (800 °C and 1000 °C) to study changes in mineralogy, microstructure and thermal behaviour, as well as their effect over the colouring power.〈/p〉 〈p〉Spinel-type 〈em〉Fd〈/em〉-3〈em〉m〈/em〉 crystalline structure was developed in all cases. Nevertheless, crystallinity parameters were highly affected by both analysed processing parameters: composition (Ψ) and post-synthesis calcination temperature (T〈sub〉c〈/sub〉). A Cr(III) enrichment along with T〈sub〉c〈/sub〉 increase favoured ion rearrangement to promote sample crystallization and crystallite growth. Fast kinetics of SCS makes Al-rich spinels with transition metals difficult to be synthesized. The application of a secondary thermal treatment resulted in a favourable evolution towards a well-crystallized structure. Lattice parameter did not seem to be affected by T〈sub〉c〈/sub〉, although it evolved indeed with composition. From a microstructural point of view, as-synthesized pigments were foamy, with a very low bulk density and nanometric grain size. After the thermal treatment, larger grain sizes were obtained, especially for the samples richer in Al and treated at higher T〈sub〉c〈/sub〉.〈/p〉 〈p〉All pigments developed intense colours in a transparent glaze without showing heterogeneities, indicating a stable behaviour against glazing process. Glaze colour evolved from green to perfectly blue shades, indicating an important dependence on composition. Nevertheless, colouring power seemed to be rather affected by calcination process.〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Radiation Measurements, Volume 119〈/p〉 〈p〉Author(s): Alessio Parisi, Luana de Freitas Nascimento, Olivier Van Hoey, Patrice Mégret, Hisashi Kitamura, Satoshi Kodaira, Filip Vanhavere〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lithium fluoride thermoluminescent radiation detectors with different dopant concentrations (〈sup〉7〈/sup〉LiF:Mg,Ti and 〈sup〉7〈/sup〉LiF:Mg,Cu,P) were exposed to 〈sup〉1〈/sup〉H and 〈sup〉4〈/sup〉He ions at the Heavy Ion Medical Accelerator in Chiba (HIMAC) in order to investigate their response to energetic light charged particles. Computer simulations with the Monte Carlo code PHITS were performed for a better interpretation of the experimental data. The results were compared with literature efficiency data and with the results of a recently developed microdosimetric efficiency model. In case of the main peak signal of 〈sup〉7〈/sup〉LiF:Mg,Ti detectors, the determined efficiency values are in good agreement with previous investigations. Discrepancies in the efficiency of high temperature signal due to well-known non-linearity effects are reported. For 〈sup〉7〈/sup〉LiF:Mg,Cu,P detectors, an anomalous thermoluminescence behavior in the low temperature part of the signal was found and discussed. Depending on the light quantification process, differences up to 30% in the dose assessment can be obtained, affecting also the relative efficiency determination process. An explanation of this phenomenon as a consequence of local migration of the charged carriers between the low temperature peaks and the main peak is presented. The implications of these findings on the use of LiF:Mg,Cu,P detectors in radiation environments characterized by the presence of 〈sup〉1〈/sup〉H and 〈sup〉4〈/sup〉He ions (i.e. space and proton therapy) are discussed. In order to avoid the occurrence of this anomalous behavior, it is advised to pre-heat the detectors after energetic light particle exposures.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Ecological Engineering, Volume 125〈/p〉 〈p〉Author(s): Cristina Lazcano, Cameron Robinson, Golnoush Hassanpour, Maria Strack〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Northern peatlands store approximately one third of the global soil carbon (C) stocks. Peat extraction for horticulture changes C fluxes turning these soils from sinks into large sources of C emitted to the atmosphere as greenhouse gases. Restoring hydrological conditions may not be enough for returning the C sink function of these ecosystems and a recovery of the original Sphagnum-dominated vegetation cover could be necessary. Here we tested the effects of the moss layer-transfer technique (MLTT) on the CO〈sub〉2〈/sub〉 and CH〈sub〉4〈/sub〉 fluxes three years after restoration of a minerotrophic cutover peatland in Quebec, Canada. Gas emissions were compared to nearby undisturbed plots, and plots with restored hydrology but without vegetation transfer. The main drivers for the observed emissions were inferred from the relationships with relevant environmental variables (vegetation cover, water table depth and temperature). Restoration of the extracted minerotrophic fen through the MLTT produced significant changes in the exchange of CO〈sub〉2〈/sub〉, bringing these fluxes closer to undisturbed plots than plots with restored hydrology only, which remained C sources throughout the study. Methane emissions were generally low across all the restored plots and far from natural levels, with only a slight increase at the MLTT restored plots observed during the third year. Even though the MLTT failed to recover the original bryophyte-dominated vegetation, the observed changes in the emissions of CO〈sub〉2〈/sub〉 and CH〈sub〉4〈/sub〉 at the restored plots were strongly associated with changes in vegetation cover (i.e. increase in vascular plants), supporting the use of this restoration technique to recover the C sink function of harvested minerotrophic peatlands.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 31 October 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil Dynamics and Earthquake Engineering〈/p〉 〈p〉Author(s): Vladimir A. Osinov, Stylianos Chrisopoulos, Theodoros Triantafyllidis〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The paper presents a numerical analysis of the dynamic deformation of the tunnel lining and the soil caused by a blast-induced pressure pulse of a moderate amplitude (several megapascals) inside the tunnel. The tunnel lining is circular and consists of individual concrete linearly elastic tubbings. The tunnel is located at a depth of 15 m in fully saturated granular soil. Effective-stress changes are described by a hypoplasticity model. The possibility of pore water cavitation at zero absolute pore pressure is taken into account. The problem is solved in a two-dimensional plane-strain formulation with the finite-element program Abaqus/Standard. Emphasis is placed on fine spatial discretization in order to obtain accurate solutions. Stresses and deformations in the lining and in the soil are analysed in detail. The solutions reveal an important role of the strong nonlinearity in the soil behaviour due to the pore water cavitation.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 514〈/p〉 〈p〉Author(s): Mahasin Ali Khan, Meghma Bera, Robert A. Spicer, Teresa E.V. Spicer, Subir Bera〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fossil leaf floras, from the latest Miocene-Pliocene Siwalik Group exposed in Bhutan, sub-Himalaya, are subjected to a CLAMP (Climate Leaf Analysis Multivariate Program) analysis using a high-resolution gridded climate calibration. The CLAMP analysis of 27 different morphotypes of fossil leaves indicates a mean annual temperature (MAT) of 24.1 °C ± 2.8 °C; a cold month mean temperature (CMMT) of 18.9 °C ± 4 °C and a warm month mean temperature (WMMT) of 27.8 °C ± 3.3 °C. The analysis also suggests a weak monsoonal climate (the monsoon index, MSI 46.7; present MSI 52) with growing season precipitation (GSP) of 1819 ± 916 mm (present GSP 2490 mm). Here we also compare palaeoclimate estimates of the latest Miocene-Pliocene Siwalik Group flora from Bhutan (c. 6 to 3.8 Ma) with those of previously investigated Siwalik Group floras from the Miocene-Pleistocene of Arunachal, India and Miocene Siwalik floras of Darjeeling, India which characterise the monsoon signature at the time of deposition. Since all the Siwalik floras of the eastern Himalaya (Darjeeling and Arunachal Pradesh) spanning the mid-Miocene to Pleistocene yield almost the same values we suggest that overall the eastern Himalayan Siwalik climate appears to have been remarkably uniform over the past 15 million years. The MAT result of the Bhutan Siwalik flora differs by just 0.6 °C from Arunachal and 1.2 °C from Darjeeling Siwalik floras. For all Siwalik fossil assemblages, WMMTs, CMMTs and LGSs (length of the growing season) are similar and consistent (WMMTs around 28 °C, CMMTs around 18 °C and LGSs around 12 months). Similarly, the mean annual relative humidity (RH) and specific humidity (SH) appear to have been uniformly around 80% and 14 g/kg respectively throughout the Neogene of the eastern Himalayan Siwaliks. Changes in the monsoon index suggest that in both Bhutan and Arunachal sub-Himalaya, there has been little change in the intensity of the monsoon since mid-Miocene time, while further west in the Darjeeling area precipitation seasonality has increased since the mid-Miocene.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0031018218303523-ga1.jpg" width="327" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Geoderma, Volume 337〈/p〉 〈p〉Author(s): R. Calvelo Pereira, M. Camps Arbestain, F.M. Kelliher, B.K.G. Theng, S.R. McNally, F. Macías, F. Guitián〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have investigated the effect of supercritical drying (SD) on the porosity and the BET-N〈sub〉2〈/sub〉 specific surface area (SSA) of five allophane-rich and three non-allophanic topsoils. The contribution of organic matter (OM) and short-range ordered (SRO) constituents to the nanoscale porosity (〈100 nm size) and SSA was also evaluated following chemical treatments to oxidise OM and then remove the SRO phase. The average pore volume and SSA of the soils, measured after SD, are greater than the values obtained after air drying. For soils that are rich in SRO constituents, oxidation of OM leads to an increase in SSA. This observation is attributed to the unblocking of pore necks previously covered by OM, while the subsequent removal of SRO constituents causes a sharp decrease in SSA. The SRO constituents containing oxalate-extractable Al, are the major contributors to the SSA of the inorganic fraction. Besides confirming that SD can help preserve the nanoscale porosity of allophane-rich soils, the results highlight the contribution of SRO constituents to the SSA of soils and their ability to accumulate OM.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Joanna Pisarska, Marta Sołtys, Joanna Janek, Agata Górny, Ewa Pietrasik, Tomasz Goryczka, Wojciech A. Pisarski〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Oxyfluoride lead-based and lead-free germanate glasses were heat-treated in order to fabricate transparent glass-ceramics. Cubic β-PbF〈sub〉2〈/sub〉 nanocrystals are well formed during crystallization of lead germanate glass. The up-conversion luminescence spectra of Er〈sup〉3+〈/sup〉 ions in lead germanate glass-ceramic system are enhanced significantly due to partial incorporation of the optically active ions into fluoride crystalline phase. These effects are not significant in oxyfluoride lead-free germanate glass after heat treatment process. The crystallization of barium gallo-germanate glass with BaF〈sub〉2〈/sub〉 is more complex and the presence of four crystalline phases BaF〈sub〉2〈/sub〉, BaO, Ba〈sub〉3〈/sub〉Ga〈sub〉2〈/sub〉Ge〈sub〉4〈/sub〉O〈sub〉14〈/sub〉 and GeO〈sub〉2〈/sub〉 was verified by X-ray diffraction measurements.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Thin Solid Films, Volume 669〈/p〉 〈p〉Author(s): Hirokazu Chiba, Rikyu Ikariyama, Shintaro Yasui, Hiroshi Funakubo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bismuth ruthenate (Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉) thin films were deposited on (111) yttria-stabilized zirconia (YSZ) single crystals and (111)YSZ//(111)Si substrates by chemical vapor deposition using Bi(CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉[2-(CH〈sub〉3〈/sub〉)〈sub〉2〈/sub〉NCH〈sub〉2〈/sub〉C〈sub〉6〈/sub〉H〈sub〉4〈/sub〉] and Ru(C〈sub〉7〈/sub〉H〈sub〉11〈/sub〉)(C〈sub〉7〈/sub〉H〈sub〉9〈/sub〉) as source materials and oxygen as a reactant gas. The film composition and X-ray diffraction 〈em〉ω〈/em〉-2〈em〉θ〈/em〉 scan profiles for thin films deposited using various source flow rate ratios revealed the existence of a process window to obtain stoichiometric Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉. Within the process window, the kind of substrates did not strongly affect the deposition rates of Bi and Ru or the Bi/Ru ratio of the deposited films. It was also confirmed that the Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 thin films grew epitaxially on both substrates within the process window. In particular, epitaxial Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 thin films grew on the Si substrate with a YSZ buffer layer. Scanning electron microscopy revealed the formation of continuous dense Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 films without any cracks or voids, and a relatively smooth interface between Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 and the YSZ buffer layer on Si. The resistivity of the Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 films was almost constant (~550 and ~950 μΩcm for the films deposited on (111)YSZ single-crystal substrates and (111)YSZ//(111)Si substrates, respectively), even when the ratio of Bi and Ru source gas flow rates was changed in the process window. In addition, the resistivity of Bi〈sub〉2〈/sub〉Ru〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 films prepared on both kinds of substrates was almost independent of temperature from 10 to 300 K.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 1 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Thin Solid Films, Volume 669〈/p〉 〈p〉Author(s): Hiroaki Uchiyama, Takahiro Bando, Hiromitsu Kozuka〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Titania (TiO〈sub〉2〈/sub〉) films were prepared from Ti(OC〈sub〉3〈/sub〉H〈sub〉7〈/sub〉〈sup〉〈em〉i〈/em〉〈/sup〉)〈sub〉4〈/sub〉 solutions of molar compositions, Ti(OC〈sub〉3〈/sub〉H〈sub〉7〈/sub〉〈sup〉〈em〉i〈/em〉〈/sup〉)〈sub〉4〈/sub〉: H〈sub〉2〈/sub〉O: HNO〈sub〉3〈/sub〉: C〈sub〉2〈/sub〉H〈sub〉5〈/sub〉OH = 1: 〈em〉x〈/em〉: 〈em〉y〈/em〉: 10 (〈em〉x〈/em〉 = 1.0–8.0, 〈em〉y〈/em〉 = 0.1–2.0), and the influence of the amount of H〈sub〉2〈/sub〉O and HNO〈sub〉3〈/sub〉 on the crystallization of the films during the heat treatment was investigated. The precipitation in the coating solutions containing a large amount of H〈sub〉2〈/sub〉O over 〈em〉x〈/em〉 = 4.0 was suppressed with increasing HNO〈sub〉3〈/sub〉 contents over 〈em〉y〈/em〉 = 1.0, where the H〈sub〉2〈/sub〉O contents in the solutions was able to be changed in the range of 〈em〉x〈/em〉 = 1.0–8.0. The increase in the H〈sub〉2〈/sub〉O contents led to the increase in the degree of crystallization, crystallite size and reflective index of the resultant TiO〈sub〉2〈/sub〉 films, while it decreased the size of the grains that were observed in the scanning electron microscope images. Anatase films with a higher refractive index of ca. 2.25 was obtained at 〈em〉x〈/em〉 = 8.0 and 〈em〉y〈/em〉 = 1.0–2.0.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Soil and Tillage Research, Volume 186〈/p〉 〈p〉Author(s): Márcio R. Nunes, Eloy A. Pauletto, José E. Denardin, Luis E.A. S. Suzuki, Harold M. van Es〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tillage and no-tillage result in different soil mechanical responses which in turn may affect crop growth. Better understanding of soil compressive behavior, therefore, is relevant for the assessment of tillage practices in agricultural systems. We studied the change in soil compressive properties and their relationship with soil physical attributes and plant growth through a chisel tillage chronosequence in a Nitisol where soil was untilled after chiseling for 24 months, 18 months, 12 months, 6 months, and zero months, and was under continuous (12-year) NT. The effects were measured for three soil depth layers: 0 to 7-cm, 7 to 17-cm and 20 to 30-cm. Mechanical chiseling was found to reduce both the degree of compactness and the pre-compression pressure compared to continuous NT, but made the soil more susceptible to new compaction. The effects of chisel tillage generally persisted for a period of 12–24 months. The degree of compactness and soil pre-compression pressure were found to be strongly correlated, and were strongly correlated with other soil physical attributes (soil penetration resistance, soil macroporosity, and soil aggregate stability). They were negatively correlated with root length, root density, and root volume, as well as stalk diameter, linking soil structure indicators to plant growth. Our results also showed that soil compressive parameter values can be estimated based on other soil physical properties that influence plant growth. These findings have potential for studies of crop response to soil structure and soil compaction and could be used to aid in choosing optimal soil management practices, in order to reduce the risk of soil compaction, linking soil compressive behavior and soil physical conditions to plant growth.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Applied Surface Science, Volumes 467–468〈/p〉 〈p〉Author(s): Cong Chen, Shouzhen Bao, Baoshun Zhang, Ying Chen, Wen Chen, Chengyu Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To reduce electromagnetic interference (EMI) and irradiation, one efficient path is to develop electromagnetic absorption (EMA) material with the aim of high-efficient convert electromagnetic wave into thermal energy. Presently strategy to design high-performance electromagnetic absorber is followed by the way of component optimization and microstructure design. This research reported an advanced HWCNTs/Fe@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 ternary absorber, which was fabricated by decorating H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 treated carbon nanotubes (HCNTs) with magnetic core-shell shaped Fe@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles. This HCNTs/Fe@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 composite exhibits various electromagnetic loss forms, including conductive, dipole, interface loss 〈em〉etc〈/em〉. which attribute to EMA ability. The largest qualified frequency width (〈em〉f〈sub〉E〈/sub〉〈/em〉) can up to 5.4 GHz with a thickness of 1.5 mm. To discuss the EMA loss mechanism, control experiments have been conducted by preparation of Fe@Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉, HCNTs@Fe@Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 composites. In this way, the attenuation mechanism can be better understood.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0169433218329179-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 536〈/p〉 〈p〉Author(s): Gang Yuan, Xiao Zhao, Yeru Liang, Lin Peng, Hanwu Dong, Yong Xiao, Chaofan Hu, Hang Hu, Yingliang Liu, Mingtao Zheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a new class of zero-dimensional carbon nanomaterials, carbon dots have triggered intensive research interest in various fields. However, the low surface area, hydrophilicity, and agglomeration characteristics limit their applications in energy storage fields. Herein, we demonstrate that nitrogen-doped carbon dots can be employed as efficient nanoenhancer to boost the electrochemical performance of three-dimensional graphene. The as-prepared materials exhibit an interconnected framework with abundant oxygen- and nitrogen-containing functional groups, which enable fast penetration and transport of electrolyte ions and provide more active sites and electric conductivity. Employed as binder-free electrode for supercapacitors, the resultant materials present high specific capacitance (338 F g〈sup〉−1〈/sup〉) and areal capacitance (604 μF cm〈sup〉−2〈/sup〉) at a current density of 0.5 A g〈sup〉−1〈/sup〉, which is much higher than that of pristine three-dimensional graphene (190 F g〈sup〉−1〈/sup〉, and 114 μF cm〈sup〉−2〈/sup〉), with an enhancement of 78% and 430%, respectively. Moreover, superior long-term cycling stability (94% of capacitance retention after 20 000 charging/discharging cycles at 10 A g〈sup〉−1〈/sup〉) as well as improved electric conductivity can also be achieved. These results certify that nitrogen-doped carbon dots can be applied as nanobooster to comprehensively improve the performance of graphene for high-performance electrochemical energy storage.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉Small nitrogen-doped carbon dots (〈em〉N〈/em〉-CDs) are employed as efficient nanoenhancer to significantly boost the electrochemical performances of three-dimensional graphene (3DG) for supercapacitors.〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979718312931-ga1.jpg" width="500" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 536〈/p〉 〈p〉Author(s): Yuanyuan Zhang, Lili Wang, Fengying Dong, Qiao Chen, Haiyan Jiang, Mei Xu, Jinsheng Shi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉-based ternary composite materials are generally synthesized by two- or multi-step method and special precursor of CO〈sub〉3〈/sub〉〈sup〉2−〈/sup〉 is usually utilized in synthesis of Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉, which are time-consuming, laborious and relatively costly. In this paper, for the first time, a facile one-step solvothermal method is used to fabricate Z-scheme Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉/Bi/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉 ternary composites. Interestingly, ethylene glycol not only acts as solvent for the reaction system, but also reduced Bi〈sup〉3+〈/sup〉 into metallic Bi and itself is oxidized to CO〈sub〉3〈/sub〉〈sup〉2−〈/sup〉, which could construct Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉. On this occasion, Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉/Bi/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉 ternary composites are obtained after one-step method. High resolution transmission electron microscopy clearly reveals each component in composites. The as-prepared samples could be applied in various photocatalytic activities. Under solar light irradiation, Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉/Bi/Bi〈sub〉2〈/sub〉WO〈sub〉6〈/sub〉 composites exhibited prominent photodegradation performances for both ciprofloxacin and bisphenol A. Meanwhile, these composites could also be used in efficient photoreduction of CO〈sub〉2〈/sub〉. The efficient photocatalytic activity could be mainly ascribed to Z-scheme electron transfer mechanism in ternary composites, which is determined by surface redox reactions, active species trapping experiment, electron spin resonance spectrum.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979718312918-ga1.jpg" width="425" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 536〈/p〉 〈p〉Author(s): Hua Guo, Ya Su, Yanling Shen, Yumei Long, Weifeng Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Optimizing heterostructure of nanocomposites holds great potential for making full use of their ability. Herein, gold nanoparticles (AuNPs) were in situ synthesized over the surface of graphitic carbon nitride (g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉) via one-step pyrolyzation route using a single source precursor. The precursor of melamine chloroauric (C〈sub〉3〈/sub〉H〈sub〉6〈/sub〉N〈sub〉6〈/sub〉H〈sup〉+〈/sup〉⋅AuCl〈sub〉4〈/sub〉〈sup〉−〈/sup〉) was obtained through chemical precipitation reaction between melamine and chloroauric acid. The morphological analysis confirmed the compact contact between Au nanoparticles and g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉. Then, the Au-g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 nanocomposites were employed to fabricate electrochemical sensor by modifying glassy carbon electrode (GCE). Electrochemical experiments showed that the Au-g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 exhibited enhanced electrocatalytic activity towards tetracycline oxidation as compared with either pure g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 or Au nanoparticles. Based on cyclic voltammetry (CV) method, the sensor was applied in the detection of tetracycline with a low detection limit of 0.03 μM (S/N = 3) and the linear range of concentration were 0.1–20 μM and 20–200 μM, respectively. Moreover, such an electrochemical sensor demonstrated high stability and good selectivity. Finally, the electrochemical sensor was applied to drug assays and exhibited sufficient precision and accuracy. Therefore, this work paves a new way of preparing g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉–based heterostructures and provides an efficient method for the detection of tetracycline in clinical analysis and quality control.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979718313018-ga1.jpg" width="419" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Colloid and Interface Science, Volume 536〈/p〉 〈p〉Author(s): Mingmei Zhang, Hong Liu, Ying Wang, Tianjiao Ma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three-dimensional (3D) flower center/petal nanostructure exhibits excellent electrochemical performance because of their unique unfold ultra-thin multi-layer structure benefit to the rapid transmission of electrons and the full infiltration of the electrolyte. A three-phase Fe〈sub〉5〈/sub〉Ni〈sub〉4〈/sub〉S〈sub〉8〈/sub〉 nanosflower is constructed by one step alcohothermal technique using a mixture solvent of glycerol, diethylene glycol and ethylenediamine. Ethylenediamine successfully functions as the complexing agent of metal ions to slowly release the metal ions in the process of reaction, which encourage the flower petal nanostructure formation. Interestingly, when the proportion of iron increased, a novel Fe〈sub〉7〈/sub〉S〈sub〉8〈/sub〉@Fe〈sub〉5〈/sub〉Ni〈sub〉4〈/sub〉S〈sub〉8〈/sub〉 flower center/petal nanostructure come into being. Benefiting from the interconnected structure of the multi-layer shell, the Fe〈sub〉7〈/sub〉S〈sub〉8〈/sub〉@ Fe〈sub〉5〈/sub〉Ni〈sub〉4〈/sub〉S〈sub〉8〈/sub〉 nanosflower displays high specific capacitance of 670.4C g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉, excellent rate capability of 79.2% (531.0C g〈sup〉−1〈/sup〉 at 20 A g〈sup〉−1〈/sup〉), and longer cycling stability of 92.1% retained capacitance after 5000 cycles. Furthermore, the assembled hybrid supercapacitor demonstrates high energy density of 49.9 Wh kg〈sup〉−1〈/sup〉 at power density of 770.0 W kg〈sup〉−1〈/sup〉. Our results provide a new strategy to design metal sulfides with special structure for application to asymmetrical supercapacitor cathode material.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉 〈p〉A three-phase core/shell flower-like Fe〈sub〉7〈/sub〉S〈sub〉8〈/sub〉@Fe〈sub〉5〈/sub〉Ni〈sub〉4〈/sub〉S〈sub〉8〈/sub〉 is successfully constructed by one step alcohothermal technique using a mixture solvent of glycerol, diethylene glycol and ethylenediamine. The as-obtained composites become a promising electrode material for the next generation energy storage devices with high specific capacitance (670.4C g〈sup〉−1〈/sup〉 at 1 A g〈sup〉−1〈/sup〉), excellent energy density (49.9 Wh kg〈sup〉−1〈/sup〉 at power density of 770.0 W kg〈sup〉−1〈/sup〉), as well as good long-term cycling stability (almost 88.9% retention after 10,000 cycles).〈/p〉 〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0021979718312906-ga1.jpg" width="496" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉 〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 562〈/p〉 〈p〉Author(s): Parisa Moazzam, Giorgio Luciano, Amir Razmjou, Ehsan Akbari, Pavel G. Ul’yanov, Soumitro Mahanty〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The degree of available energy on a surface determines how a surface interacts with its surrounding environment such as corrosion. Current approaches to protection of Aluminum surfaces from corrosion mainly focus on adding an organic or inorganic layer to either act as a barrier from oxidant or scarifying to inhibit the corrosion. Altering the surface energy of Al on a molecular level is another alternative approach to efficiently modify the Al surface without the need for another thick expensive protective or scarifying materials. Herein, an attempt was made to understand how a molecular scale energy alteration improves the anticorrosion behavior of an aluminum surface. Two different surface engineering alteration strategies have been discussed; termed ALOSH and ALTSH modification. A variety of analytical instruments, i.e., FTIR, EDAX, XPS, SEM, AFM, WCA, and SFE measurement were used to systematically characterize the samples. Electrochemical impedance spectroscopy revealed that there are different resistances after the surface modifications. The trapping air resistance appeared in ALTSH is approximately 2.4 and 36 times higher than that of ALOSH and bare samples, respectively. The potentiostat analysis results showed that the mili inch per year value of coating for ALTSH was 0.012 while that of ALOSH was 0.507. It was also found that the low surface energy alteration without using inert molecules is not enough to render corrosion inhibition property, as it needs to have a protective energy barrier with no or minimal active electrochemical behavior.〈/p〉〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0927775718311294-ga1.jpg" width="320" alt="Graphical abstract for this article" title=""〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Computational Physics, Volume 379〈/p〉 〈p〉Author(s): Takashi Shiroto, Naofumi Ohnishi, Yasuhiko Sentoku〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For more than half a century, most of the plasma scientists have encountered a violation of the conservation laws of charge, momentum, and energy whenever they have numerically solved the first-principle equations of kinetic plasmas, such as the relativistic Vlasov–Maxwell system. This fatal problem is brought by the fact that both the Vlasov and Maxwell equations are indirectly associated with the conservation laws by means of some mathematical manipulations. Here we propose a quadratic conservative scheme, which can strictly maintain the conservation laws by discretizing the relativistic Vlasov–Maxwell system. A discrete product rule and summation-by-parts are the key players in the construction of the quadratic conservative scheme. Numerical experiments of the relativistic two-stream instability and relativistic Weibel instability prove the validity of our computational theory, and the proposed strategy will open the doors to the first-principle studies of mesoscopic and macroscopic plasma physics.〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface Science, Volume 681〈/p〉 〈p〉Author(s): Xuejiang Chen, Yuan Li〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Stepped morphologies on vicinal 3C- and 4H-SiC (0001) surfaces with the miscut toward 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈mo〉[〈/mo〉〈mn〉1〈/mn〉〈mover〉〈mn〉1〈/mn〉〈mo〉¯〈/mo〉〈/mover〉〈mn〉00〈/mn〉〈mo〉]〈/mo〉〈/mrow〉〈/math〉 or 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈mo〉[〈/mo〉〈mn〉11〈/mn〉〈mover〉〈mn〉2〈/mn〉〈mo〉¯〈/mo〉〈/mover〉〈mn〉0〈/mn〉〈mo〉]〈/mo〉〈/mrow〉〈/math〉 directions have been studied with a three-dimensional kinetic Monte Carlo model. In the model, a three-dimensional lattice mesh was established based on the crystal lattice of 3C-and 4H-SiC to fix the positions of atoms and interatomic bonding. Periodic boundary conditions were applied in the lateral direction while helicoidal boundary conditions were used in the direction of crystal growth. Events, such as adatoms attachment, detachment and interlayer transport at the step edges, and adatoms adsorption and diffusion on the terraces were considered in the model. Effects of Ehrlich–Schwoebel barriers at downward step edges and incorporation barriers at upwards step edges were also considered. Moreover, the atoms of silicon and carbon were treated as the minimal diffusing species independently to achieve more elaborate information for the behavior of atoms in the crystal surface. The simulation results showed that multiple-height steps were formed on the vicinal 4H-SiC (0001) surfaces, whereas single bilayer-height stepped morphologies were observed on the vicinal 3C-SiC (0001) surfaces. Furthermore, zigzag shaped edges were observed for both of 3C- and 4H-SiC (0001) surfaces with the miscut toward 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.gif" overflow="scroll"〉〈mrow〉〈mo〉[〈/mo〉〈mn〉11〈/mn〉〈mover〉〈mn〉2〈/mn〉〈mo〉¯〈/mo〉〈/mover〉〈mn〉0〈/mn〉〈mo〉]〈/mo〉〈/mrow〉〈/math〉 direction. At last, the formation mechanism of the stepped morphology was also analyzed.〈/p〉〈/div〉 〈h5〉Graphical abstracts〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0039602818304618-fx1.jpg" width="301" alt="Image, graphical abstract" title="Image, graphical abstract"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 3 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 442〈/p〉 〈p〉Author(s): Jie Zhang, Edwin Reynders, Guido De Roeck, Geert Lombaert〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Many civil engineering structures have a repetitive or quasi-periodic geometry. Such structures have clustered modes with closely spaced natural frequencies corresponding to mode shapes with similar wavelengths. Such modes may be difficult to distinguish in modal tests and lead to difficulties when pairing calculated and experimentally determined modal characteristics in vibration-based model updating. For repetitive structures, the free wave characteristics, i.e. propagation constants and free waves, can be used alternatively to characterize their dynamic behaviour. The free wave characteristics can therefore be used instead of modal characteristics as data features in model updating of repetitive structures. This paper investigates the feasibility of model updating of repetitive structures based on free wave characteristics. First, the identification of the free wave characteristics from the measured vibration responses of a periodic structure is investigated. A stabilization diagram is constructed to pick up the stable free waves. Second, model updating of repetitive structures is performed through a match of the calculated and experimentally identified free wave characteristics. A least-squares cost function is formulated and minimized using a gradient-based optimization algorithm. This algorithm requires the sensitivity of the free wave characteristics to the model parameters that need to be updated. The analytical expressions for the free wave sensitivities are therefore derived. The proposed model updating procedure is demonstrated and validated by a numerical case study involving a repetitive frame structure and by an experiment on a four-storey steel frame structure. The results confirm the feasibility of model updating based on free wave characteristics for repetitive structures.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 3 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 442〈/p〉 〈p〉Author(s): Timo Theurich, Johann Gross, Malte Krack〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A linear vibration absorber can be tuned to effectively suppress the resonance of a particular vibration mode. It relies on the targeted energy transfer into the absorber within a narrow and fixed frequency band. Nonlinear energy sinks (NES) have a similar working principle. They are effective in a much wider frequency band but generally only in a limited range of excitation levels. To design NES, their working principle must be thoroughly understood. We consider a particular type of NES, a small mass undergoing impacts and dry friction within a cavity of a base structure (vibro-impact NES or impact absorber). The nonlinear dynamic regimes under near-resonant forcing and resulting operating ranges are first revisited. We then investigate how off-resonant vibration modes and dissipation via impacts and dry friction contribute to the vibration suppression. Moreover, we assess the effectiveness of the impact absorber for suppressing multiple resonances in comparison to a linear tuned vibration absorber (LTVA) and a pure friction damper with the same mass.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 3 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 442〈/p〉 〈p〉Author(s): Arian Bahrami〈/p〉

Beschreibung: 〈p〉Publication date: 3 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 442〈/p〉 〈p〉Author(s): Chuan-Xing Bi, Yuan Liu, Yong-Bin Zhang, Liang Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The equivalent source method (ESM)-based sound field separation technique has been successfully introduced into near-field acoustic holography as a preprocessing tool to eliminate the influence of disturbing sources or reflections from the opposite side of the array. In this paper, that technique is further extended in a sparsity framework, which makes it possible to take the advantage of the theory of compressive sensing to achieve reasonable separation accuracy with a limited number of spatial sampling points. In this study, three sparse bases are considered, including two existing bases that are suitable for spatially sparse and spatially extended sources, respectively, and a more flexible, redundant sparse basis that is constructed by combining the two sparse bases above, and the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mrow〉〈msub〉〈mi〉ℓ〈/mi〉〈mn〉1〈/mn〉〈/msub〉〈mo〉-〈/mo〉〈mtext〉norm〈/mtext〉〈/mrow〉〈/math〉 minimization is used to promote sparse solutions. Numerical simulation and experimental results demonstrate the validity of the proposed technique and show the superiority of the use of the redundant sparse basis. Besides, the effects of the relative strength of the target source to the disturbing source, the number of spatial sampling points and the signal-to-noise ratio on the separation accuracy are analyzed numerically.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 3 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 442〈/p〉 〈p〉Author(s): N.G.R. de Melo Filho, L. Van Belle, C. Claeys, E. Deckers, W. Desmet〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To enhance the sound insulation performance of double panel partitions at their mass-air-mass resonance frequency, novel compact and low-mass solutions are sought. This paper investigates the use of the locally resonant vibro-acoustic metamaterial concept as a possible solution. The metamaterial solution is applied to one panel of a double panel partition in order to enhance the sound transmission loss at the mass-air-mass resonance. To design the metamaterial solution and predict its sound transmission loss performance, an extension of the multiple reflection theory is proposed, incorporating the dynamic mass of a metamaterial panel. The latter is obtained from the metamaterial plate dispersion curves, calculated using finite element based unit cell modeling. The designed metamaterial solution is manufactured and its insertion loss is measured. The novel design outperforms the original double panel and an equivalent total mass double panel configuration in the targeted mass-air-mass resonance frequency region. The predictions obtained with the proposed method are in good agreement with the experimentally obtained results. This demonstrates the potential of the metamaterial solution to enhance the acoustic insulation at the mass-air-mass resonance and indicates that the proposed method allows a fast, simple and representative indication of their acoustic insulation performance.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 3 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 442〈/p〉 〈p〉Author(s): Zengwei Wang, Zhike Peng, Xi Shi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a method combining the structural modification method and an optimization algorithm is proposed for virtual decoupling of mechanical systems. The proposed method offers an alternative for virtual decoupling of mechanical systems in a very different way from the in-situ decoupling method, and performs better than the current virtual decoupling method for the relatively rigid links between subsystems. The relationship between structural modification and structural decoupling is first derived. A strategy for virtual decoupling of mechanical systems is presented, in which transfer functions of the modified system is used as an optimization object. Finally, the proposed method is validated by numerical and experimental case studies.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 3 March 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Sound and Vibration, Volume 442〈/p〉 〈p〉Author(s): Florian J. Krömer, Stéphane Moreau, Stefan Becker〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The type of fan-blade skew used in axial fans has a strong impact on the sound field, the flow field and their interrelations. In this study, the sound emission and the velocity distributions of three low-pressure axial fans with a similar design point and forward-, backward- and unskewed fan blades are investigated. The forward skewed fan is found to have best aerodynamic performance as well as the least sound emission over a broad operating range. More detailed investigations at the fan design point, based on sound pressure spectra and beamforming evaluations, reveal very dominant subharmonic narrowband components and increased turbulence-ingestion noise for the backward- and the unskewed fan. Moreover, an increase in the meridional velocity in the tip region is observed for the forward-skewed fan, which weakens the tip-vortex formation. For the backward- and the unskewed fan however, a reduced meridional velocity in the tip region is found, which is an indicator of an intensified tip gap flow. Additionally, values of the turbulent kinetic energy are substantially increased for the backward- and the unskewed fan, which also hints at unsteady flow phenomena in the tip region. These flow processes are linked to the subharmonic narrowband sound emission. Finally, unsteady flow features in the tip region lead to an increase in turbulence-ingestion noise.〈/p〉〈/div〉 〈/div〉