排序方式: 共有12条查询结果,搜索用时 31 毫秒
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目的探究妊娠晚期阴道B族链球菌(group B Streptococcus,GBS)的感染对肠道菌群和妊娠结局的影响。方法选取2018年3月至2019年11月大连市中心医院孕检并分娩的妊娠妇女744人为对象,调查并统计B族链球菌的感染率;筛选有和没有B族链球菌感染妊娠妇女各47人,调查不良妊娠结局的发生率;选取信息匹配的妊娠晚期阴道B族链球菌感染和未感染的妊娠妇女,采集粪便样本,提取菌群DNA,用16S rDNA方法分析菌群变化。结果744名妊娠妇女中B族链球菌检出49例,感染率为6.59%;B族链球菌感染组总的不良妊娠发生比例为76.6%,正常组发生比例为27.7%(χ^2=5.491,P<0.05)。B族链球菌感染组妊娠妇女胎膜早破(χ^2=16.177,P<0.01)、难产(χ^2=21.134,P<0.01)和羊水异常(χ^2=22.989,P<0.05)的发生率与未感染组比较显著增高。B族链球菌感染组妊娠妇女肠道菌群发生显著变化。结论妊娠晚期阴道B族链球菌的感染可能引起肠道菌群紊乱,增加不良妊娠结局。 相似文献
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Saber Hamdani Hongru Wang Guangyong Zheng Shahnaz Perveen Mingnan Qu Naveed Khan Waqasuddin Khan Jianjun Jiang Ming Li Xinyu Liu Xiaocen Zhu Govindjee Chengcai Chu Xin‐Guang Zhu 《Physiologia plantarum》2019,166(1):105-119
The maximum quantum yield of photosystem II (as reflected by variable to maximum chlorophyll a fluorescence, Fv/Fm) is regarded as one of the most important photosynthetic parameters. The genetic basis underlying natural variation in Fv/Fm, which shows low level of variations in plants under non‐stress conditions, is not easy to be exploited using the conventional gene cloning approaches. Thus, in order to answer this question, we have followed another strategy: we used genome‐wide association study (GWAS) and transgenic analysis in a rice mini‐core collection. We report here that four single‐nucleotide polymorphisms, located in the promoter region of β‐glucosidase 5 (BGlu‐5), are associated with observed variation in Fv/Fm. Indeed, our transgenic analysis showed a good correlation between BGlu‐5 and Fv/Fm. Thus, our work demonstrates the feasibility of using GWAS to study natural variation in Fv/Fm, suggesting that cis‐element polymorphism, affecting the BGlu‐5 expression level, may, indirectly, contribute to Fv/Fm variation in rice through the gibberellin signaling pathway. Further research is needed to understand the mechanism of our novel observation. 相似文献
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Hamdani Saber Khan Naveed Perveen Shahnaz Qu Mingnan Jiang Jianjun Govindjee Zhu Xin-Guang 《Photosynthesis research》2019,139(1-3):107-121
Photosynthesis Research - Non-photochemical quenching (NPQ) of the excited state of chlorophyll a is a major photoprotective mechanism plants utilize to survive under high light. Here, we report... 相似文献
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Xin Sun Jingru Liu Bin Lu Peng Zhang Mingnan Zhao 《The International Journal of Life Cycle Assessment》2017,22(9):1373-1383
Purpose
This study presents a life cycle assessment (LCA)-based sustainable and lightweight automotive engine hood design and compares the life cycle energy consumption and potential environmental impacts of a steel (baseline) automotive engine hood with three types of lightweight design: advanced high strength steel (AHSS), aluminum, and carbon fiber.Methods
A “cradle-to-grave” LCA including the production, use, and end-of-life stages is conducted in accordance with the ISO 14040/14044 standards. Onsite data collected by Chinese automotive companies in 2015 are used in the assessment. The Cumulative Energy Demand v1.09 method is applied to evaluate cumulative energy demand (CED), and the International Panel on Climate Change 2013 100a method is used to estimate global warming potential (GWP 100a).Results and discussion
Among the different lightweight designs for the engine hood, the aluminum design is the most sustainable and has the lowest CED and GWP (100a) from a life cycle perspective, which is based on a lifetime driving distance of approximately 150,000 km. In addition, the AHSS design is also sustainable and lightweight. The carbon fiber design results in higher CED and GWP (100a) values than the steel (baseline) design during the life cycle but results in the largest CED and GWP (100a) savings through waste material recycling. The AHSS design exhibits the best break-even distance based on CED and GWP (100a) within 150,000 km.Conclusions
Sensitivity analysis results show that the lifetime driving distance and material recycling rate have the largest impacts on the overall CEDs and GWPs of the three lightweight designs.5.
Khan Naveed Essemine Jemaa Hamdani Saber Qu Mingnan Lyu Ming-Ju Amy Perveen Shahnaz Stirbet Alexandrina Govindjee Govindjee Zhu Xin-Guang 《Photosynthesis research》2021,150(1-3):137-158
Photosynthesis Research - Photosynthesis can be probed through Chlorophyll a fluorescence induction (FI), which provides detailed insight into the electron transfer process in Photosystem II, and... 相似文献
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The impact of modifying photosystem antenna size on canopy photosynthetic efficiency—Development of a new canopy photosynthesis model scaling from metabolism to canopy level processes 下载免费PDF全文
Qingfeng Song Yu Wang Mingnan Qu Donald R. Ort Xin‐Guang Zhu 《Plant, cell & environment》2017,40(12):2946-2957
Canopy photosynthesis (Ac) describes photosynthesis of an entire crop field and the daily and seasonal integrals of Ac positively correlate with daily and seasonal biomass production. Much effort in crop breeding has focused on improving canopy architecture and hence light distribution inside the canopy. Here, we develop a new integrated canopy photosynthesis model including canopy architecture, a ray tracing algorithm, and C3 photosynthetic metabolism to explore the option of manipulating leaf chlorophyll concentration ([Chl]) for greater Ac and nitrogen use efficiency (NUE). Model simulation results show that (a) efficiency of photosystem II increased when [Chl] was decreased by decreasing antenna size and (b) the light received by leaves at the bottom layers increased when [Chl] throughout the canopy was decreased. Furthermore, the modelling revealed a modest ~3% increase in Ac and an ~14% in NUE was accompanied when [Chl] reduced by 60%. However, if the leaf nitrogen conserved by this decrease in leaf [Chl] were to be optimally allocated to other components of photosynthesis, both Ac and NUE can be increased by over 30%. Optimizing [Chl] coupled with strategic reinvestment of conserved nitrogen is shown to have the potential to support substantial increases in Ac, biomass production, and crop yields. 相似文献
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Pan Li Tiangen Chang Shuoqi Chang Xiang Ouyang Mingnan Qu Qingfeng Song Langtao Xiao Shitou Xia Qiyun Deng Xin-Guang Zhu 《植物学报(英文版)》2018,60(12):1154-1180
A large number of genes related to source, sink,and flow have been identified after decades of research in plant genetics. Unfortunately, these genes have not been effectively utilized in modern crop breeding. This perspective paper aims to examine the reasons behind such a phenomenon and propose a strategy to resolve this situation. Specifically, we first systematically survey the currently cloned genes related to source, sink, and flow;then we discuss three factors hindering effective application of these identified genes, which include the lack of effective methods to identify limiting or critical steps in a signaling network, the misplacement of emphasis on properties, at the leaf, instead of the whole canopy level,and the non-linear complex interaction between source,sink, and flow. Finally, we propose the development of systems models of source, sink and flow, together with a detailed simulation of interactions between them and their surrounding environments, to guide effective use of the identified elements in modern rice breeding. These systems models will contribute directly to the definition of crop ideotype and also identification of critical features and parameters that limit the yield potential in current cultivars. 相似文献
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We examined interactions in a soluble tapasin (TPN)/HLA-B*0801 complex to gain mechanistic insights into the functions of TPN. Results show that TPN acts as a chaperone by increasing the ratio of active-to-inactive peptide-deficient HLA-B*0801 molecules in solution. TPN causes peptides to associate and dissociate faster owing to its effect on widening the binding groove of HLA-B*0801 molecules. Our data indicate that a TPN-assisted mechanism of peptide selection relies on disruption of conserved hydrogen bonds at the C-terminal end of the groove. Peptide sequence-dependent interactions along the entire length of the groove also play a role in this mechanism. We suggest that TPN influences presentation of antigenic peptides according to a mechanistically complicated process in which bound candidate peptides that are unable to conformationally disengage TPN from class I molecules are excluded from the repertoire. Overall, these studies unify our understanding of the functions of TPN. 相似文献
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Antibiotics resistance of Helicobacter pylori in children with upper gastrointestinal symptoms in Hangzhou,China 下载免费PDF全文