ALBERT

Description: The ligands 2-pyrazol-1-yl-1H-indole (HL1) and 2- 1 , 2 , 4 -triazol-1-yl-1H-indole (HL2) individually reacted with Ti(NMe 2 ) 4 in tetrahydrofuran to form the corresponding complexes Ti(L1) 2 (NMe 2 ) 2 ( 1 ) and Ti(L2) 2 (NMe 2 ) 2 ( 2 ), respectively. The titanium complexes were fully characterized by NMR measurement and elemental analysis as well as the single-crystal X-ray diffraction of 1 and 2 . Both 1 and 2 exhibit high activities towards intermolecular hydroamination of terminal alkynes with high selectivity, and they also efficiently promote the ring-opening polymerization of ϵ-caprolactone.

Description: In the mammalian ovaries, the primordial follicle pool determines the reproductive capability over the lifetime of a female. The primordial follicle is composed of two cell members, namely the oocyte and the pre-granulosa cells that encircle the oocyte. However, it is unclear what factors are involved in the reorganization of the two distinct cells into one functional unit. This study was performed to address this issue. Firstly, in an in vitro reconstruction system, dispersed ovarian cells from murine fetal ovaries at 19.0 days post coitum (dpc) reassembled into follicle-like structures, independent of the physical distance between the cells, implying that either oocytes or ovarian somatic cells (OSCs) were motile. We then carried out a series of transwell assay experiments, and determined that it was in fact 19.0 dpc OSCs (as opposed to oocytes), which exhibited a significant chemotactic response to both fetal bovine serum and oocytes themselves. We observed that S100A8, a multi-functional chemokine, may participate in the process as it is mainly expressed in oocytes within the cysts/plasmodia. S100A8 significantly promoted the number of migrating OSCs by 2.5 times in vitro , of which 66.9% were FOXL2 protein-positive cells, implying that the majority of motile OSCs were pre-granulosa cells. In addition, an S100A8-specific antibody inhibited the formation of follicle-like reconstruction cell mass in vitro . And, the primordial follicle formation was reduced when S100a8 -specific siRNA was applied onto in vitro cultured 17.5 dpc ovary. Therefore, S100A8 could be a chemokine of oocyte origin, which attracts OSCs to form the primordial follicles. This article is protected by copyright. All rights reserved

Description: Two-dimensional (2D) materials are being used widely for chemical sensing applications due to their large surface-to-volume ratio and photoluminescence (PL) emission and emission exciton band tunability. To better understand how the analyte affects the PL response for a model 2D platform, we used atomic force microscopy (AFM) and co-localized photoluminescence (PL) and Raman mapping to characterize tungsten disulfide (WS2) flakes on template-stripped gold (TSG) under acetone challenge. We determined the PL-based response from single- and few-layer WS2 arises from three excitons (neutral, A0; biexciton, AA; and the trion, A−). The A0 exciton PL emission is the most strongly quenched by acetone whereas the A− PL emission exhibits an enhancement. We find the PL behavior is also WS2 layer number dependent.

Description: Lactobacillus is a fairly diverse genus of bacteria with more than 260 species and subspecies. Many profiling methods have been developed to carry out phylogenetic analysis of this complex and diverse genus, but limitations remain since there is still a lack of comprehensive and accurate analytical method to profile this genus at species level. To overcome these limitations, a Lactobacillus-specific primer set was developed targeting a hypervariable region in the groEL gene—a single-copy gene that has undergone rapid mutation and evolution. The results showed that this methodology could accurately perform taxonomic identification of Lactobacillus down to the species level. Its detection limit was as low as 104 colony-forming units (cfu)/mL for Lactobacillus species. The assessment of detection specificity using the Lactobacillus groEL profiling method found that Lactobacillus, Pediococcus, Weissella, and Leuconostoc genus could be distinguished, but non-Lactobacillus Genus Complex could not be detected. The groEL gene sequencing and Miseq high-throughput approach were adopted to estimate the richness and diversity of Lactobacillus species in different ecosystems. The method was tested using kurut (fermented yak milk) samples and fecal samples of human, rat, and mouse. The results indicated that Lactobacillus mucosae was the predominant gut Lactobacillus species among Chinese, and L. johnsonii accounted for the majority of lactobacilli in rat and mouse gut. Meanwhile, L. delbrueckii subsp. bulgaricus had the highest relative abundance of Lactobacillus in kurut. Thus, this groEL gene profiling method is expected to promote the application of Lactobacillus for industrial production and therapeutic purpose.

Description: Lead-free single crystal ( Na 1/2 Bi 1/2 ) TiO 3 –1.5 at.% Bi ( Zn 1/2 Ti 1/2 ) O 3 (NBT–1.5BZT) with dimension of Φ35 mm × 12 mm was successfully grown by a top-seeded solution growth technique. The average and local structure were studied by a combination of X-ray diffraction and Raman spectroscopy. The electric and optical properties of 〈001〉-oriented single crystals were investigated systematically. Compared with pure NBT, the piezoelectric constant and transmission coefficient were both enhanced, that is, from 62 pC/N and ~60% to 121 pC/N and ~70%, respectively. Furthermore, domain structure observation suggested that the 〈110〉-oriented tetragonal ferroelastic domains in NBT were suppressed at room temperature with addition of BZT, which was responsible for the improved piezoelectric and optical properties of NBT–1.5BZT single crystal.

Description: ABSTRACT Titanium dioxide nanoparticles (TiO 2 NPs) have been used in environmental management, food, medicine, and industry. But TiO 2 NPs have been demonstrated to cross the blood–brain barrier and store up in the brain organization, leading to glutamate-mediated neurotoxicity. However, the neurotoxicity in the brain is not well understood. In this study, mice were exposed to 1.25, 2.5, or 5 mg/kg body weight TiO 2 NPs for 9 months, and the glutamate–glutamine cyclic pathway and expressions of glutamate receptors associated with the hippocampal neurotoxicity were investigated. Our findings showed elevations of glutamate release and phosphate-activated glutaminase activity, and reductions in glutamine and glutamine synthetase in the hippocampus following exposure to TiO 2 NPs. Furthermore, TiO 2 NPs significantly inhibited the expression of N -methyl- d -aspartate receptor subunits (including NR1, NR2A, and NR2B) and metabotropic glutamate receptor 2 in mouse hippocampus. These findings suggest that the imbalance of glutamate metabolism triggered inhibitions of glutamate receptor expression in the TiO 2 NP-exposed hippocampus. © 2014 Wiley Periodicals, Inc. Environ Toxicol, 2014.

Description: Abstract A series of low‐temperature firing ceramics with scheelite structure, [Ca0.55(Sm1‐xBix)0.3]MoO4 (x = 0.2–0.95), were prepared via solid‐state reaction. The sintering temperature ranges from 660 to 760°C. A standard tetragonal scheelite phase was formed without secondary phase. When the x value was 0.95, the temperature coefficient of resonant frequency (τf) moved to a near zero value (−2.1 ppm/°C) with a dielectric constant 13.7 and the quality factor (Qf) of 33 200 GHz. The Raman spectra shows that the more vibration modes appeared with x value, which is due to the increasing of Bi concentration and results in increase in permittivities and decrease in Qf values. The classical harmonic oscillator model is used in the infrared spectra and extrapolate to the microwave range. The [Ca0.55(Sm1‐xBix)0.3]MoO4 ceramics show high‐performance microwave dielectric properties at low‐sintering temperature.

Description: The occurrence of adverse weather exacerbates traffic flow conditions, often leading to severe traffic congestions. Many studies have been conducted based on field-collected data to obtain the effects of weather on traffic flow characteristics. However, there is a limitation for filed data-based studies, in that weather conditions and traffic conditions are both noncontrollable and nonrepeatable, making it difficult to comprehensively assess the influence of weather conditions, especially the rare extreme weather conditions, on traffic flow characteristics. This paper proposes to assess these effects with the combination of driving simulator and traffic simulation. A driving simulator can collect driving behavior by conducting weather-related driving simulation experiments, while a microscopic traffic simulation program can evaluate the changes in traffic flow characteristics by inputting driving behavior parameters coming from the driving simulator. The proposed method can overcome the limitation of the field data-based approach. In this paper, the structure of the assessment platform is introduced at first. Then a verification experiment is conducted to measure the influences of adverse weather conditions on traffic flow characteristics. The verification experiment results show that the influences of adverse weather on traffic flow characteristics have consistent tendencies with outcomes from previous research and demonstrate that the method is practicable for the analysis of the influence of weather on traffic flow characteristics. This paper provides a practical way to analyze the influence of weather on traffic flow from driving behavior’s point of view.

Description: A novel high-performance carbon foam (CF) was fabricated through the addition of phenolic resin (PR) into a coal tar pitch (CTP) based precursor. The effects of mass fraction of a PR additive on the crystalline structures, morphologies, compressive strength (σ) and thermal conductivity (λ) of resultant CF material were investigated systematically. Characterization showed a strong dependence of CF’s performance from the composition and optical texture of the precursor, which were mainly depending on the polycondensation and polymerization reactions between PR and raw CTP. Comparing with the strength of pristine CF at 6.5 MPa, the σ of mCF-9 (13.1 MPa) was remarkably enhanced by 100.1%. However, the λ of mCF-9 substantially reduced to 0.9 m−1K−1 compared with 18.2 W m−1K−1 of pristine CF. Thus, this modification strategy to produce microporous CF materials from raw CTP provides a new protocol for the fabrication of high-performance carbon based materials.

Description: In Northern China, many regions and cities are located in semi-arid regions, and groundwater is even the only source of water to support human survival and social development. Affected by human activities, the Bashang (BS) region (including Zhangjiakou City and part of Xilin Gol League) have showed a significant decline in groundwater levels in recent years. However, in the BS region, the causes for the decline in groundwater level were not clear. In this study, we used time series of multi-source data Moderate Resolution Imaging Spectroradiometer (MODIS), Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) to analyze vegetation and groundwater changes based on linear regression models. The variation trends of NDVI (Normalized Difference Vegetation Index, derived from MODIS) and GWSA (groundwater storage anomaly, derived from GRACE and GLDAS) indicated the increasingly better vegetation in the agriculture planting areas, partially degraded vegetation in the grassland, and the declining groundwater level in the whole study region. In order to assess the impact of human-induced factors on vegetation and groundwater, the R U E s e a s o n a l calculation model was proposed based on RUE (rain use efficiency) in this study. The R U E s e a s o n a l calculation results showed that human-induced factors promoted the growth of vegetation in agricultural areas and accelerated the consumption of groundwater. In addition, we also obtained temporal and spatial distributions of human activities-affected regions. The area affected by human-induced factors in the south-central study area increased, which accelerated the decline in groundwater levels. From bulletin data, we found that the increasing tourists and vegetable production are respectively the most important factors for the increased consumption of urban water and agricultural water. Based on multi-source data, the influences of various human-induced factors on the ecological environment were explored and the area affected by human-induced factors was estimated. The results provide the valuable guidance for water resource management departments. In the BS region, it is necessary to regulate agricultural water use and strengthen residential water management.