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排序方式: 共有970条查询结果,搜索用时 201 毫秒
31.
Judith Morales Suvi Ruuskanen Toni Laaksonen Tapio Eeva Rafael Mateo Eugen Belskii Elena V. Ivankina Antero Järvinen Anvar Kerimov Erkki Korpimäki Indrikis Krams Raivo Mänd Chiara Morosinotto Markku Orell Anna Qvarnström Heli Siitari Fred M. Slater Vallo Tilgar Marcel E. Visser Wolfgang Winkel Herwig Zang Juan Moreno 《Journal of avian biology》2013,44(2):111-120
The expression and impact of maternal effects may vary greatly between populations and environments. However, little is known about large‐scale geographical patterns of variation in maternal deposition to eggs. In birds, as in other oviparous animals, the outermost maternal component of an egg is the shell, which protects the embryo, provides essential mineral resources and allows its interaction with the environment in the form of gas exchange. In this study, we explored variation of eggshell traits (mass, thickness, pore density and pigmentation) across 15 pied flycatcher populations at a large geographic scale. We found significant between‐population variation in all eggshell traits, except in pore density, suggesting spatial variation in their adaptive benefits or in the females’ physiological limitations during egg laying. Between‐ population variation in shell structure was not due to geographic location (latitude and longitude) or habitat type. However, eggshells were thicker in populations that experienced higher ambient temperature during egg laying. This could be a result of maternal resource allocation to the shell being constrained under low temperatures or of an adaptation to reduce egg water loss under high temperatures. We also found that eggshell colour intensity was positively associated with biliverdin pigment concentration, shell thickness and pore density. To conclude, our findings reveal large‐ scale between‐population variation of eggshell traits, although we found little environmental dependency in their expression. Our findings call for further studies that explore other environmental factors (e.g. calcium availability and pollution levels) and social factors like sexual selection intensity that may account for differences in shell structure between populations. 相似文献
32.
Lishan Wang Weidong Zang Jiang Liu Dongli Xie Weidong Ji Yaosheng Pan Zhiqiang Li Jiawei Shen Yongyong Shi 《PloS one》2013,8(4)
ObjectivesTo assess the association between the variant of Cytochrome P450 2A6 whole gene deletion (CYP2A6*4) polymorphism and risk of lung cancer.MethodsTwo investigators independently searched the PubMed, Elsevier, EMBASE, Web of Science, Wiley Online Library and Chinese National Knowledge Infrastructure (CNKI). Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for CYP2A6*4 and lung cancer were calculated in a fixed-effects model (the Mantel-Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate.ResultsThis meta-analysis included seven eligible studies, which included 2524 lung cancer cases and 2258 controls (cancer–free). Overall, CYP2A6*4 was associated with the risk of lung cancer (allele*4 vs. allele non-*4, pooled OR = 0.826, 95% CI = 0.725−0.941, P-value = 0.004). When stratifying for population, significant association was observed in Asian (additive model, pooled OR = 0.794, 95% CI = 0.694−0.909, P-value = 0.001; dominant model, pooled OR = 0.827, 95% CI = 0.709−0.965, P-value = 0.016; recessive model (pooled OR = 0.444, 95% CI = 0.293−0.675, P-value <0.0001). In the overall analysis, a comparably significant decrease in the frequency of *4/*4 genotype was detected between cases and controls in Asian while no *4/*4 genotype was detected in Caucasian in collected data.ConclusionThis meta-analysis suggests that the CYP2A6*4 polymorphism is associated with susceptibility of lung cancer in Asian. The whole gene deletion of CYP2A6 may decrease the risk of lung cancer in Asian samples. 相似文献
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Zhihai Mao Jing Sun Bo Feng Junjun Ma Lu Zang Feng Dong Daohai Zhang Minhua Zheng 《PloS one》2013,8(7)
Metastasis remains to be one of the most prevalent causes leading to poor long-term survival of colorectal cancer (CRC) patients. The clinical significances of tumor metastatic suppressor, N-myc downregulated gene 1 (NDRG1), have been inconsistently reported in a variety of cancerous diseases. In this study with 240 CRC clinical specimens, we showed that NDRG1 expression was significantly decreased in most of CRC tissues compared to the paired non-tumor counterparts. Statistical analysis revealed a significant inverse correlation of NDRG1 expression with tumor stage, differentiation status and metastasis. Compared with NDRG1-negative group, NDRG1-positve group had better disease-free/overall survival (p = 0.000) over 5 years’ follow-up. Furthermore, NDRG1 was considered to be an independent prognostic factor for overall survival (p = 0.001) and recurrence (p = 0.003). Our study concludes that NDRG1 is a novel favorable predictor for the prognosis in CRC patients. 相似文献
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Distribution and budget of dissolved and biogenic silica in the Bohai Sea and Yellow Sea 总被引:2,自引:0,他引:2
Jun Liu Jiaye Zang Lex Bouwman Sen Liu Zhigang Yu Xiangbin Ran 《Biogeochemistry》2016,130(1-2):85-101
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Developing new ABX3‐type perovskites is very important for expanding the family of perovskites and obtaining excellent light absorbing material. One strategy is replacing A site atoms with super‐alkali atoms for the perovskites, but super‐alkali perovskites with stable dynamics performance and high efficiency have not been found until now. Herein, massive super‐alkalis, such as Li3O, Li2F, H5O2, and so on, are introduced into the cubic CH3NH3PbI3 perovskites, and the perovskites with these super‐alkalis are systematically studied by using ab initio molecular dynamics simulation and density functional theory based first principles calculations. Calculated results indicate that the perovskites with the super‐alkalis including metal atoms show unstable dynamics performance under normal temperature and pressure. On the contrary, the first obtainable super‐alkali perovskites of cubic H5O2MBr3 (M = Ge, Sn, Pb) and H5O2PbI3 show stable dynamics performance. They also show suitable tolerance factors, negative formation energies, tunable direct band gaps, and small effective hole and electron masses. Moreover, the calculated power conversion efficiencies of 23.17% and 22.83% are obtained for the single‐junction solar cells based on the cubic H5O2SnBr3 and H5O2PbBr3 perovskites, respectively. 相似文献
40.
Jiangying Cao Jie Zang Xiujie Kong Chunlong Zhao Ting Chen Yingying Ran Hang Dong Wenfang Xu Yingjie Zhang 《Bioorganic & medicinal chemistry》2019,27(6):978-990
Aminopeptidase N (APN) has been proved to be deeply associated with cancer angiogenesis, metastasis and invasion. Therefore, APN gains increasing attention as a promising anti-tumor target. In the current study, we report the design, synthesis, biological evaluation and structure-activity relationship of one new series of leucine ureido derivatives containing the 1,2,3-triazole moiety. Among them, compound 31f was identified as the best APN inhibitor with IC50 value being two orders of magnitude lower than that of the positive control bestatin. Compound 31f possessed selective cytotoxicity to several tumor cell lines over the normal cell line human umbilical vein endothelial cells (HUVECs). Notably, when combined with 5-fluorouracil (5-Fu), 31f exhibited synergistic anti-proliferation effect against several tumor cell lines. At the same concentration, 31f exhibited much better anti-angiogenesis activities than bestatin in the HUVECs capillary tube formation assay and the rat thoracic aorta rings test. In the in vitro anti-invasion assay, 31f also exhibited superior potency over bestatin. Moreover, considerable in vivo antitumor potencies of 31f alone or in combination with 5-Fu were observed without significant toxic signs in a mouse heptoma H22 tumor transplant model. 相似文献