167 research outputs found

    Why is son preference so persistent in East and South Asia? a cross-country study of China, India, and the Republic of Korea

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    Son preference has persisted in the face of sweeping economic and social changes in China, India, and the Republic of Korea. The authors attribute this to their similar family systems, which generate strong disincentives to raise daughters while valuing adult women's contributions to the household. Urbanization, female education, and employment can only slowly change these incentives without more direct efforts by the state and civil society to increase the flexibility of the kinship system such that daughters and sons can be perceived as being more equally valuable. Much can be done to this end through social movements, legislation, and the mass media.Gender and Development,Health Monitoring&Evaluation,Anthropology,Public Health Promotion,Population&Development,Adolescent Health,Anthropology,Life Sciences&Biotechnology,Health Monitoring&Evaluation,Population&Development

    Plasmonically enhanced photoluminescence of monolayer MoS2 via nanosphere lithography-templated gold metasurfaces

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    We demonstrate a simple, cost-effective method to enhance the photoluminescence intensity of monolayer MoS2. A hexagonal symmetric Au metasurface, made by polystyrene nanosphere lithography and metal coating, is developed to enhance the photoluminescence intensity of monolayer MoS2. By using nanospheres of different sizes, the localized surface plasmon resonances of the Au metasurfaces can be effectively tuned. By transferring monolayer MoS2 onto the Au metasurface, the photoluminescence signal of the monolayer MoS2 can be significantly enhanced up to 12-fold over a square-centimeter area. The simple, large-area, cost-effective fabrication technique could pave a new way for plasmon-enhanced light-mater interactions of atomically thin two-dimensional materials.This work was supported in part by National Natural Science Foundation of China (Grant No. 62075093 and 61805113), China Postdoctoral Science Foundation (2020M672697), Natural Science Foundation of Guangdong Province (Grant No. 2018A030310224 and 2019A1515110864), Guangdong Innovative and Entrepreneurial Research Team Program (Grant No. 2017ZT07C071), and Shenzhen Science and Technology Innovation Commission (Grant No. GJHZ201809281552 07206, JCYJ20170817111349280, and JCYJ2018030518063 5082). Meng Zhao acknowledges the support from the Agency for Science, Technology and Research (A*STAR) (Grant No. 152700014 and H19H6a0025)

    Identification of the ADPR binding pocket in the NUDT9 homology domain of TRPM2

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    Activation of the transient receptor potential melastatin 2 (TRPM2) channel occurs during the response to oxidative stress under physiological conditions as well as in pathological processes such as ischemia and diabetes. Accumulating evidence indicates that adenosine diphosphate ribose (ADPR) is the most important endogenous ligand of TRPM2. However, although it is known that ADPR binds to the NUDT9 homology (NUDT9-H) domain in the intracellular C-terminal region, the molecular mechanism underlying ADPR binding and activation of TRPM2 remains unknown. In this study, we generate a structural model of the NUDT9-H domain and identify the binding pocket for ADPR using induced docking and molecular dynamics simulation. We find a subset of 11 residues—H1346, T1347, T1349, L1379, G1389, S1391, E1409, D1431, R1433, L1484, and H1488—that are most likely to directly interact with ADPR. Results from mutagenesis and electrophysiology approaches support the predicted binding mechanism, indicating that ADPR binds tightly to the NUDT9-H domain, and suggest that the most significant interactions are the van der Waals forces with S1391 and L1484, polar solvation interaction with E1409, and electronic interactions (including π–π interactions) with H1346, T1347, Y1349, D1431, and H1488. These findings not only clarify the roles of a range of newly identified residues involved in ADPR binding in the TRPM2 channel, but also reveal the binding pocket for ADPR in the NUDT9-H domain, which should facilitate structure-based drug design for the TRPM2 channel

    Platinum-nickel alloy excavated nano-multipods with hexagonal close-packed structure and superior activity towards hydrogen evolution reaction

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    铂镍合金在氢析出(HER)、氧还原(ORR)等重要能量转化反应中具有优异催化性质,受到了人们广泛的关注。近日,谢兆雄教授课题组通过简单的溶剂热方法,首次合成出六方晶系的铂镍合金枝状纳米晶,其中每个枝杈结构由六个{11-20}高能晶面裸露的超薄纳米片组装而成。与面心立方晶系铂镍合金相比,亚稳态的六方晶系铂镍合金在HER反应中表现出更加优异的性质。当电流密度为10 mA·cm-2时,其过电位仅有65 mV,同时质量电流密度高达3.03 mA·µgPt-1 (-70 m V vs. RHE),是目前为止报道的HER催化剂中质量活性最高的,其突出的催化性能主要来源于晶相作用(同质异晶)及大的比表面积。该项工作为发展高催化性能的铂基合金纳米晶提供了新的研究思路。该研究是在谢兆雄教授和蒋亚琪副教授指导下,与傅钢教授共同合作完成。实验部分由博士生曹振明(第一作者)、陈巧丽、沈守宇、卢邦安,硕士生李慧齐以及博士后张嘉伟共同完成,理论计算部分由傅钢教授课题组完成。【Abstract】Crystal phase regulations may endow materials with enhanced or new functionalities. However, syntheses of noble metal-based allomorphic nanomaterials are extremely difficult, and only a few successful examples have been found. Herein, we report the discovery of hexagonal close-packed Pt–Ni alloy, despite the fact that Pt–Ni alloys are typically crystallized in face-centred cubic structures. The hexagonal close-packed Pt–Ni alloy nano-multipods are synthesized via a facile one-pot solvothermal route, where the branches of nano-multipods take the shape of excavated hexagonal prisms assembled by six nanosheets of 2.5nm thickness. The hexagonal close-packed Pt–Ni excavated nano-multipods exhibit superior catalytic property towards the hydrogen evolution reaction in alkaline electrolyte. The overpotential is only 65mV versus reversible hydrogen electrode at a current density of 10 mAcm-2 , and the mass current density reaches 3.03mA µgPt-1 at -70mV versus reversible hydrogen electrode, which outperforms currently reported catalysts to the best of our knowledge.This work was supported by the National Basic Research Program of China (Grant 2015CB932301), the National Natural Science Foundation of China (Grants 21333008, 21603178 and J1030415) and the Natural Science Foundation of Fujian Province of China (No. 2014J01058). 该研究工作得到科技部(批准号:2015CB932301)、国家自然科学基金委(批准号:21333008, 21603178 和 J1030415)和福建省自然科学基金委(No. 2014J01058)的大力资助与支持

    Associations of Educational Attainment, Occupation, Social Class and Major Depressive Disorder among Han Chinese Women

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    Background The prevalence of major depressive disorder (MDD) is higher in those with low levels of educational attainment, the unemployed and those with low social status. However the extent to which these factors cause MDD is unclear. Most of the available data comes from studies in developed countries, and these findings may not extrapolate to developing countries. Examining the relationship between MDD and socio economic status in China is likely to add to the debate because of the radical economic and social changes occurring in China over the last 30 years. Principal findings We report results from 3,639 Chinese women with recurrent MDD and 3,800 controls. Highly significant odds ratios (ORs) were observed between MDD and full time employment (OR = 0.36, 95% CI = 0.25–0.46, logP = 78), social status (OR = 0.83, 95% CI = 0.77–0.87, logP = 13.3) and education attainment (OR = 0.90, 95% CI = 0.86–0.90, logP = 6.8). We found a monotonic relationship between increasing age and increasing levels of educational attainment. Those with only primary school education have significantly more episodes of MDD (mean 6.5, P-value = 0.009) and have a clinically more severe disorder, while those with higher educational attainment are likely to manifest more comorbid anxiety disorders. Conclusions In China lower socioeconomic position is associated with increased rates of MDD, as it is elsewhere in the world. Significantly more episodes of MDD occur among those with lower educational attainment (rather than longer episodes of disease), consistent with the hypothesis that the lower socioeconomic position increases the likelihood of developing MDD. The phenomenology of MDD varies according to the degree of educational attainment: higher educational attainment not only appears to protect against MDD but alters its presentation, to a more anxious phenotype

    Quality Characteristics of Karst Plateau Tea (Niaowang) in Southwest China and Their Relationship with Trace Elements

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    This study investigated the relationship between the characteristics of quality components and trace elements of Niaowang tea from Guizhou Province in mountainous plateau areas. The contents of catechin monomers and eight other trace elements were measured using high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The results showed that the tender summer leaves of Niaowang tea in Guizhou Province had the highest content of catechins at 3558.15~2226.52 μg·g−1. The content of ester catechins was the highest in summer, amounting to 69.75~72.42% of the total catechins. The content of non-ester catechins was the highest in autumn, reaching 52.54~62.28% of the total catechins; among ester catechins, the mass fraction of epigallocatechin gallate (EGCG) showed a pattern of mature summer leaves > tender summer leaves > mature autumn leaves > tender autumn leaves, and the mass fractions of gallocatechin gallate (GCG) and epicatechin gallate (ECG) were larger in autumn than in summer; gallocatechin (GC) had no significant correlation with different trace elements, and Mn had no significant correlations with different catechin monomers. EGCG was significantly negatively correlated with As, Se, Hg, Pb, Ni, and Zn. Additionally, gallic acid (GA) was significantly negatively correlated with As, Hg and Ni. Other catechin monomers were largely significantly positively correlated with trace elements. The biochemical indicators of the phenotype of Niaowang tea show that the summer and autumn buds are suited for making high-quality green tea

    Using Energy Difference for Speech Separation of Dual-microphone Close-talk System

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    Using the computational auditory scene analysis (CASA) as a framework, a novel speech separation approach based on dual-microphone energy difference (DMED) is proposed for close-talk system. The energy levels of the two microphones are calculated in time-frequency (T-F) units. The DMEDs are calculated as the energy level ratio between the two microphones, and used as a cue to estimate the signal to noise ratio (SNR) and ideal binary mask (IBM) for mix-acoustic of the close-to-mouth microphone. The binary masked units are grouped to generate the target speech. Test with speeches and different noises show that the algorithm is more than 95 % accurate. As the T-F units’ length increase, the accuracy increase as well. Using automatic speech recognition (ASR) analysis, we show that the proposed algorithm improves speech quality in actual close talk system
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