分类： 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间： 2016-05-11
Yan, Yan
Wang, Hao
Chen, Hanqing
Lindstrom-Battle, Anya
Jiao, Renjie
Yan, Yan
Chen, Hanqing
Wang, Hao
Jiao, Renjie
摘要： Body size is one of the features that distinguish one species from another in the biological world. Animals have developed mechanisms to control their body size during normal development. However, how animals cope with genetic alterations and/or environmental stresses to develop into normal-sized adults remain poorly understood. The ability of the animals to develop into a normal-sized adult after the challenges of genetic alterations and/or environmental stresses reveals a robustness of body size control. Here we show that the mutation of dGPAT4, a de novo synthase of lysophosphatidic acid, is a genetic alteration that triggers such a robust response of the animals to body size challenges in Drosophila. Loss of dGPAT4 leads to a severe delay of development, slow growth and resultant small-sized animals during the larval stages, but results in normal-sized adult flies. The robust body size adjustment of the dGPAT4 mutant is likely achieved by corresponding changes in ecdysone and insulin signaling, which is also manifested by compromised food intake. Thus, we propose that a strategy has been evolved by the animals to reach final body size when challenged by genetic alterations, which requires the coordinated ecdysone and insulin signaling.
分类： 化学 >> 物理化学 提交时间： 2017-11-05 合作期刊: 《结构化学》
摘要： Three new coordination polymers, namely [Zn(FDA)(phen)(H2O)·H2O]n (1), [Cd(HFDA)(phen)2(NO3)] (2) and [Cd(FDA)(phen)]n (3) (H2FDA = 2,5-furandicarboxylic acid, phen = 1,10-phenanthroline) have been synthesized by the solvothermal method and characterized by elemental analysis, IR, powder X-ray diffraction, thermogravimetric analysis and X-ray single-crystal diffraction analysis. For 1, the neighboring Zn2+ ions are bridged by FDA2- as linkers to form one-dimensional (1D) chains, and phen ligands are as the terminal ligands. Furthermore, the 1D chains are packed into a three-dimensional (3D) supramolecular structure through hydrogen bonds and π-π interactions. For 2, the H2FDA ligand is partial deprotonation, which is a rare phenomenon among other coordination polymers based on H2FDA. Under the synergetic effect of phen ligands and the partial deprotonation of H2FDA, the structure of 2 is discrete. For 3, the Cd2+ ions are linked by two carboxylates of FDA2- ligand to give rise to 1D zig-zag chains, and phen ligands chelate the Cd2+ ions like 1. In addition, solid-state luminescent spectra of three coordination polymers were also studied at room temperature.
分类： 生物学 >> 生物物理学 提交时间： 2016-05-15
Wang, Lijuan
Zhang, Bei
Wang, Hao
Li, Mei
Niu, Qiuli
Wen, Shaojun
Wang, Lijuan
Zhang, Bei
Wang, Hao
Li, Mei
Niu, Qiuli
Wen, Shaojun
Zhou, Jiapeng
Chen, Yubao
Zhou, Jiapeng
Chen, Runsheng
摘要： Background: Aldosterone synthase (CYP11B2) is one of the most studied candidate genes related to essential hypertension (EH) and left ventricular hypertrophy (LVH). Some studies have focused on the relationship between -344C/T polymorphism (rs1799998) in the CYP11B2 gene and LVH, but the results are controversial. This meta-analysis is purposed to reveal the relationship between the -344C/T and the left ventricular structure and function, including left ventricular end diastolic dimension (LVEDD), left ventricular end systolic diameter (LVESD), left ventricular mass/left ventricular mass index (LVM/LVMI), left ventricular posterior wall thickness (LVPWT), and interventricular septal wall thickness (IVS). Methods: A literature search of PubMed and Embase databases was conducted on articles published before January 27, 2014. The odds ratios with 95% confidence intervals were calculated. Heterogeneity analyses were performed using meta-regression. Tests for publication bias were also performed and biased studies should be removed from subsequent analyses. Results: There were 20 studies with a total of 6780 subjects meeting the inclusion criteria. The main finding was that concentration levels of LVEDD and LVESD were higher in CC homozygous individuals than in TT homozygous individuals in the whole group. In the Asian subgroup, TT homozygous individuals had larger IVS than CC homozygous individuals. In the Caucasian normotension subgroup, CC homozygous individuals had larger LVM/LVMI than TT homozygous individuals. In the Asian essential hypertension subgroup, TT homozygous individuals had larger LVPWT values than CC homozygous individuals. Conclusions: The present findings support the hypothesis that CC homozygous individuals may have greater left ventricular diameters (LVEDD and LVESD) regardless of their ethnicities or physical conditions.
分类： 生物学 >> 植物学 >> 应用植物学 提交时间： 2020-05-31 合作期刊: 《干旱区科学》
摘要： In arid areas, ecological degradation aroused by over-exploitation of fresh water, expansion of artificial oasis and shrinkage of natural oasis, has drawn attention of many scholars and officials. The water and ecological footprints can be used to quantitatively evaluate the water consumption of social-economic activities and their influence on the eco-environments. In addition, increase of the water footprint indicates the expansion of artificial oasis, and the influence on the natural oasis could be reflected by the variation of the ecological footprint. This study was conducted to answer a scientific question that what is the quantitative relationship between the expansion of the artificial oasis and the degradation of the natural oasis in the arid environments of Xinjiang, China. Thus, based on the social-economic data, water consumption data and meteorological data during 2001–2015, we calculated the water and ecological footprints to express the human-related pressure exerted on the water resources and arid environments in Xinjiang (including 14 prefectures and cities), and explore the relationship between the water and ecological footprints and its mechanism by using the coupling analysis and Granger causality test. The results show that both the water and ecological footprints of Xinjiang increased significantly during 2001–2015, and the increasing rate of the ecological footprint was much faster than that of the water footprint. The coupling degree between the water and ecological footprints was relatively high at the temporal scale and varied at the spatial scale. Among the 14 prefectures and cities examined in Xinjiang, the greater social-economic development (such as in Karamay and Urumqi) was associated with the lower coupling degree between the two footprints. Increases in the water footprint will cause the ecological footprint to increase, such that a 1-unit increase in the consumption of water resources would lead to 2–3 units of ecological degradation. The quantitative relationship between the increases of the water and ecological footprints, together with the intensities of water consumption both in the natural and artificial oases of Tarim River Basin, have approved the fact that the formation and expansion of 1 unit of the artificial oasis would bring about the degradation of 2 units of the natural oasis. These conclusions not only provide a technical basis for sustainable development in Xinjiang, but also offer a theoretical guide and scientific information that could be used in similar arid areas around the world.
分类： 环境科学技术及资源科学技术 >> 环境科学技术基础学科 提交时间： 2020-04-23 合作期刊: 《干旱区科学》
摘要： In arid areas, ecological degradation aroused by over-exploitation of fresh water, expansion of artificial oasis and shrinkage of natural oasis, has drawn attention of many scholars and officials. The water and ecological footprints can be used to quantitatively evaluate the water consumption of social-economic activities and their influence on the eco-environments. In addition, increase of the water footprint indicates the expansion of artificial oasis, and the influence on the natural oasis could be reflected by the variation of the ecological footprint. This study was conducted to answer a scientific question that what is the quantitative relationship between the expansion of the artificial oasis and the degradation of the natural oasis in the arid environments of Xinjiang, China. Thus, based on the social-economic data, water consumption data and meteorological data during 2001–2015, we calculated the water and ecological footprints to express the human-related pressure exerted on the water resources and arid environments in Xinjiang (including 14 prefectures and cities), and explore the relationship between the water and ecological footprints and its mechanism by using the coupling analysis and Granger causality test. The results show that both the water and ecological footprints of Xinjiang increased significantly during 2001–2015, and the increasing rate of the ecological footprint was much faster than that of the water footprint. The coupling degree between the water and ecological footprints was relatively high at the temporal scale and varied at the spatial scale. Among the 14 prefectures and cities examined in Xinjiang, the greater social-economic development (such as in Karamay and Urumqi) was associated with the lower coupling degree between the two footprints. Increases in the water footprint will cause the ecological footprint to increase, such that a 1-unit increase in the consumption of water resources would lead to 2–3 units of ecological degradation. The quantitative relationship between the increases of the water and ecological footprints, together with the intensities of water consumption both in the natural and artificial oases of Tarim River Basin, have approved the fact that the formation and expansion of 1 unit of the artificial oasis would bring about the degradation of 2 units of the natural oasis. These conclusions not only provide a technical basis for sustainable development in Xinjiang, but also offer a theoretical guide and scientific information that could be used in similar arid areas around the world.
分类： 核科学技术 >> 核科学与技术 提交时间： 2023-06-16
Wang, Hao
Lai, Yuecheng
Zhong, Jiajun
Liu, Yunpeng
Yao, Lei
Qian, Lixiong
Xing, Xueqing
Chen, Zhongjun
Mo, Guang
Wu, Zhonghua
摘要： In certain exceptional cases, capillary samples must be used to measure X-ray absorption spectra (XAS). However, the inhomogeneous thickness of capillary samples causes XAS distortion. This study discusses the distortion and correction of the XAS curve caused by the inhomogeneous thickness of capillary samples. The relationship between the distorted XAS curve mdeq (measured values) and the real absorption coefficient msdeq (true values) of the sample was established. The distortion was slight and negligible when the vertical size (2h) of the X-ray beam spot was smaller than 60% of the capillary tubes inner diameter (2Rin). When h/Rin >1, X-ray leakage is inevitable and should be avoided during measurement. Partial X-ray leakage caused by an X-ray beam spot size larger than the inner diameter of the capillary tube leads to serious compressed distortion of the XAS curve. When h/Rin <1, the distorted XAS data were well corrected. Possible errors and their influence on the corrected XAS are also discussed. Simulations and corrections for distortions verify the feasibility and effectiveness of the corrected method.
分类： 物理学 >> 地球物理学、天文学和天体物理学 提交时间： 2024-02-01 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： During the long term evolution of globular clusters (GCs), some member stars are lost to the field. The recently found nitrogen-rich (N-rich) metal-poor field stars are promising candidates of these GC escapees, since N enhancement is the fingerprint of chemically enhanced populations in GCs. In this work, we discuss the possibility of identifying N-rich metal-poor field stars with the upcoming Chinese Space Station Telescope (CSST). We focus on the main survey camera with NUV, u, g, r, i, z, y filters and slitless spectrograph with a resolution about 200. The combination of UV sensitive equipment and prominent N-related molecular lines in the UV band bodes well for the identification: the color–color diagram of (u − g) versus (g − r) is capable of separating N-rich field stars from normal halo stars, if metallicity can be estimated without using the information on u-band photometry. Besides, the synthetic spectra show that a signal-to-noise ratio of 10 is sufficient to identify N-rich field stars. In the near future, a large sample of N-rich field stars found by CSST, combined with state-of-the-art N-body simulations will be crucial to deciphering GC-Galaxy co-evolution.
分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-05-02
Yan, HQ [Yan, Hongqiang][ 1 ]
Sun, C [Sun, Chuang][ 1 ]
Fang, ZP [Fang, Zhengping][ 1 ]
Liu, XQ [Liu, Xiaoqing][ 2 ]
Zhu, J [Zhu, Jin][ 2 ]
Wang, H [Wang, Hao][ 3 ]
摘要： An intrinsically flame retardant bio-based benzoxazine (diphenolic acid pentaerythritol caged phosphate benzoxazine, DPA-PEPA-Boz) monomer was synthesized from bio-based diphenolic acid (DPA) using a four-step process. The monomer of DPA-PEPA-Boz was characterized by FT-IR, 1H NMR and 13C NMR. The curing behavior of DPA-PEPA-boz was studied and compared with those of DPA based benzoxazine (DPA- Boz) and DPA ester derivative (MDP) based benzoxazine (MDP-Boz) without PEPA by means of non- isothermal differential scanning calorimetry. The results indicated that DPA-PEPA-Boz system showed a two-stage curing, assigned to the exothermic opening reactions of oxazine rings and PeOeC ring in PEPA respectively, while the DPA-Boz and MDP-Boz showed a one-stage curing. In addition, the effect of the introduction of PEPA on thermal and inflammable properties of the resin was evaluated. The residual char of the cured DPA-PEPA-Boz (P-DPA-PEPA-Boz) after 400 C was much higher than those of cured DPA-Boz (P-DPA-Boz) and cured MDP-Boz (P-MDP-Boz) under nitrogen and air atmospheres. Meanwhile, total heat release (THR), peak heat release rate (PHRR) and heat release capacity (HRC) of P-DPA-PEPA- Boz were about half of those of P-DPA-Boz and P-MDP-Boz. P-DPA-PEPA-Boz had a limiting oxygen index (LOI) of 33.5% and achieved V0 rating in UL94 test. P-DPA-PEPA-Boz behaved as a very good intrinsic thermal and flame retardant bio-based benoxazine resin.
点击量
待评议
点击量
下载量
评论
通过
