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991.
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SHEN Samuel S.P. 《中国科学:生命科学英文版》2005,48(1):41-48
Based on the physico-biophysical considerations, mathematical analysis and some approximate formulations generally adopted in meteorology and ecology, an ecological dynamic model of grassland is developed. The model consists of three interactive variables, i.e. the bio-mass of living grass, the biomass of wilted grass, and the soil wetness. The major biophysical processes are represented in parameterization formulas, and the model parameters can be determined inversely by using the observational climatological and ecological data. Some major parameters are adjusted by this method to fit the data (although incomplete) in the Inner Mongolia grassland, and other secondary parameters are estimated through sensitivity studies. The model results are well agreed with reality, e.g., (i) the maintenance of grassland requires a minimum amount of annual precipitation (approximately 300 mm); (ii) there is a significant relationship between the annual precipitation and the biomass of living grass; and (iii) the overgrazing will eventually result in desertification. A specific emphasis is put on the shading effect of the wilted grass accumulated on the soil surface. It effectively reduces the soil surface temperature and the evaporation, hence benefits the maintenance of grassland and the reduction of water loss in the soil. 相似文献
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995.
Efficient and Hysteresis‐Free Perovskite Solar Cells Based on a Solution Processable Polar Fullerene Electron Transport Layer
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Ying‐Chiao Wang Xiaodong Li Liping Zhu Xiaohui Liu Wenjun Zhang Junfeng Fang 《Liver Transplantation》2017,7(21)
Fullerene derivatives, which possess extraordinary geometric shapes and high electron affinity, have attracted significant attention for thin film technologies. This study demonstrates an important photovoltaic application using carboxyl‐functionalized carbon buckyballs, C60 pyrrolidine tris‐acid (CPTA), to fabricate electron transport layers (ETLs) that replace traditional metal oxide‐based ETLs in efficient and stable n‐i‐p‐structured planar perovskite solar cells (PSCs). The uniform CPTA film is covalently anchored onto the surface of indium tin oxide (ITO), significantly suppressing hysteresis and enhancing the flexural strength in the CPTA‐modified PSCs. Moreover, solution‐processable CPTA‐based ETLs also enable the fabrication of lightweight flexible PSCs. The maximum‐performing device structures composed of ITO/CPTA/CH3NH3PbI3/2,2′,7,7′‐tetrakis‐(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD)/Au yield power conversion efficiencies of more than 18% on glass substrates and up to 17% on flexible substrates. These results indicate that the CPTA layers provide new opportunities for solution‐processed organic ETLs by substantially simplifying the procedure for fabricating PSCs for portable applications. 相似文献
996.
Leilei?Xu Chao?Xia Xiaodong?Qin Weixiang?Sun Nelson?Leung-Sang?Tang Yong?Qiu Jack?Chun-Yiu?Cheng Zezhang?ZhuEmail author 《Molecular genetics and genomics : MGG》2017,292(4):789-794
Adolescent idiopathic scoliosis (AIS) is a structural curvature of the spine that was estimated to affect millions of children worldwide. Recent study shows that the functional variant rs10738445 could add to the risk of AIS through the regulation of BNC2 gene. This study aims to investigate whether the rs10738445 of BNC2 gene is a functional susceptible locus for AIS in the Chinese population and to further clarify the association of the BNC2 expression with the curve severity. SNP rs10738445 was genotyped in 1952 patients and 2492 controls, and further replicated in 693 patients and 254 controls. We found that patients have a significantly higher frequency of CC than the controls (21.9 vs. 17.7%, p?=?0.004 for stage 1; 12.6 vs. 7.9%, p?=?0.03 for stage 2). Allele C can significantly add to the risk of AIS with an OR of 1.14–1.24. AIS patients were found to have significantly higher BNC2 expression than the controls. The BNC2 expression was significantly correlated with the curve severity (r?=?0.316, p?=?0.02). In conclusion, our study suggests a functional role of BNC2 in the development and progression of the spinal deformity in AIS. 相似文献
997.
The climate has important influences on the distribution and structure of forest ecosystems, which may lead to vital feedback to climate change. However, much of the existing work focuses on the changes in carbon fluxes or water cycles due to climate change and/or atmospheric CO2, and few studies have considered how and to what extent climate change and CO2 influence the ecosystem structure (e.g., fractional coverage change) and the changes in the responses of ecosystems with different characteristics. In this work, two dynamic global vegetation models (DGVMs): IAP‐DGVM coupled with CLM3 and CLM4‐CNDV, were used to investigate the response of the forest ecosystem structure to changes in climate (temperature and precipitation) and CO2 concentration. In the temperature sensitivity tests, warming reduced the global area‐averaged ecosystem gross primary production in the two models, which decreased global forest area. Furthermore, the changes in tree fractional coverage (ΔFtree; %) from the two models were sensitive to the regional temperature and ecosystem structure, i.e., the mean annual temperature (MAT; °C) largely determined whether ΔFtree was positive or negative, while the tree fractional coverage (Ftree; %) played a decisive role in the amplitude of ΔFtree around the globe, and the dependence was more remarkable in IAP‐DGVM. In cases with precipitation change, Ftree had a uniformly positive relationship with precipitation, especially in the transition zones of forests (30% < Ftree < 60%) for IAP‐DGVM and in semiarid and arid regions for CLM4‐CNDV. Moreover, ΔFtree had a stronger dependence on Ftree than on the mean annual precipitation (MAP; mm/year). It was also demonstrated that both models captured the fertilization effects of the CO2 concentration. 相似文献
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999.
B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) belonging to the tumour necrosis factor (TNF) ligand family can bind three unusual TNF receptors (BCMA, TACI and BR3) with various binding affinities. BAFF and APRIL are regarded as promising therapeutic targets for autoimmune diseases because of their pivotal roles in cell survival and immune regulation. In this work, we carried out molecular dynamics calculations to explore the structural and chemical features responsible for ligand recognition by extracellular functional segments of TNF receptors. We found that the conserved pocket Dcons of BAFF/APRIL contacted the DxL motif of TNF receptors, while the Dspe1–3 sub-domains were responsible for their different affinities, especially Dspe1 and Dspe2. The residues at position II–V of DxL motif were wrapped into the Dcons pocket via salt-bridge and hydrophobic interactions. The hydrophobic residues of strand3 and helix1 in TNF receptors provided remarkable contributions for the affinities to BAFF/APRIL. Additionally, ArgVI of DxL motif played a key role in the binding selectivity via salt-bridge interaction with residue D275B in BAFF. Arg27 in BCMA contributed to the high affinity for APRIL so that BCMA showed a preference for APRIL. Our studies indicated that Arg84 and Gln95 in TACI2 played an important role in the selectivity of two cysteine-rich domain segments in TACI, leading to the higher binding affinities of TACI2 than those of TACI1. The primary cause of the disability to bind APRIL was the space conflict with the rigid conformation of the C-terminus coil of BR3. These thorough understanding of the molecular mechanism for BAFF/APRIL recognition by their receptors provides new insights for guiding inhibitor design. 相似文献
1000.
Picroside II Inhibits RANKL‐Mediated Osteoclastogenesis by Attenuating the NF‐κB and MAPKs Signaling Pathway In Vitro and Prevents Bone Loss in Lipopolysaccharide Treatment Mice
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Xiaobin Yang Wenjie Gao Biao Wang Xiaodong Wang Hua Guo Yuan Xiao Lingbo Kong Dingjun Hao 《Journal of cellular biochemistry》2017,118(12):4479-4486