A New Comparison Principle for Impulsive Functional Differential Equations

通过归纳总结建立了一种关于具有有限时滞的脉冲泛函微分方程的新的比较原理,并利用这种比较原理,得到了几个时滞脉冲微分方程稳定性的充分条件。最后举出了一个例子来说明研究结果的有效性。In this paper,we establish a new comparison principle for impulsive differential systems with time delay,then,using this comparison principle,we obtain some sufficient conditions for several stabilities of impulsive delay differential equations.Finally,we present an example to show the effectiveness of our results

Phytoplankton community structures revealed by pigment signatures in Norwegian and Greenland Seas in summer 2012

对2012年中国第5次北极科学考察期间的挪威海和格陵兰海两个断面的光合色素进行了高效液相色谱(HPlC)分级分析,通过藻类色素化学分类分析软件(CHEMTAX)获得了不同浮游植物类群对叶绿素A的贡献,进而得到该海域表层和次表层(30 M)的浮游植物群落结构。结果表明:表层总叶绿素A的浓度为23.59 ng/l,低于次表层的30.38 ng/l,其中浮游植物根据粒径划分对总叶绿素A的贡献由高到低依次是微型浮游植物、小型浮游植物和微微型浮游植物。该海域同时存在葱绿叶绿素(PrASInO)、墨角藻黄素(fuCO)、别藻黄素(AllO)、多甲藻素(PErId)、玉米黄素(zEA)、19-丁墨甲藻黄素(19'bf)和19-六已墨甲藻黄素(19'Hf)等色素,其浓度和分布与温盐和营养盐等环境因子存在一定的相关性。不同粒径浮游植物色素组成显示,微微型浮游植物群落中以S型定鞭藻(28%)、n型定鞭藻(21%)、硅藻(18%)和青绿藻(12%)占优;微型浮游植物群落的优势类群为S型定鞭藻(53%)、n型定鞭藻(20%)和硅藻(12%);而小型浮游植物群落主要为硅藻(63%)和甲藻(17%)。Composition of phytoplankton controlled not only the formation of the Food Chain,but also the efficiency of energy transfer.At the same time,phytoplankton influenced the distribution of nutrient and the sedimentation of organic particulate matter.So study of phytoplankton community structures plays an important role in understanding the ecological function of phytoplankton.Photosynthetic pigments needed by photosynthesis,are very good biomarkers.They can be used to research and characterize phytoplankton community structure.Norwegian and Greenland Seas which are influenced by the Arctic water with low temperature and salinity and Atlantic water with high temperature and salinity.Understanding of correlation between environmental factors and phytoplankton community structure,is important for understanding the community structure of the marine organisms and their ecological function.During the 5thChinese Arctic Research Expedition in summer 2012,we analyze the photosynthetic pigments fromNorwegian and Greenland Seas by HPLC.Contributions of different phytoplankton assemblages to Chlorophyll a were obtained by Chemical Taxonomy( CHEMTAX),and thus resulted in composition of the phytoplankton community structure at the surface and subsurface water( about 30 m depth).The result showed that average concentration of Chlorophyll a at surface water was 23.59 ng / L,lower than that at upper water( 30.38 ng / L).The contributions of phytoplankton to Chlorophyll a were nano-> micro-> pico-one.Prasinoxanthin,Fucoxanthin,Alloxanthoxyletin,Peridinin,Zeaxanthin,19'-but-fucoxanthin,19-hexanoyloxyfucoxanthin were observed in the waters.Their distributions were relative to environmental factors,including Nutrients,temperature and salinity.These photosynthetic pigments showed negative correlations with temperature and salinity.Whereas they showed positive relations with nutrients,including NO-2,NO-3,SiO3 2-and PO3-4.The correlations of different phytoplankton and environmental factors were different.Diatoms had a very significant positive correlation with SiO3 2-,but had no correlation with PO3-4,NO-2and NO-3; Haptophytes-N had significant positive correlations with PO3-4,NO-2and NO-3; Haptophytes-S also had a positive correlation with PO3-4,but had no correlation with NO-2and NO-3.The maximum values of these photosynthetic pigments,except for Zea and Fuco,existed in the subsurface of the section BB.The distribution and concentration of photosynthetic pigments could explain the distribution and abundance of the phytoplankton to some extent.Not only because the pigments are complex and multiple,but also because there are inevitable errors in the testing and sampling,we cant determine the existence and abundance of the phytoplankton.So we use the CHEMTAX to obtain the contributions of different phytoplankton assemblages to Chlorophyll a,and thus resulted in composition of phytoplankton community structure.The composition of phytoplankton showed that Haptophytes-S( 28%), Haptophytes-N( 21%),Diatoms( 18%),and Prasinophytes( 12%) were main assemblages in the picoplankton; the main composition of nanophytoplankton were Haptophytes-S( 53%),Haptophytes-N( 20%),and Diatoms( 12%); meanwhile, Diatoms( 63%) dominated the microphytoplankton,followed by Dinoflagellates( 17%).Haptophytes-S,Haptophytes-N and Diatoms were dominant species in the surface and subsurface of section BB and AT belonging to the Norwegian and Greenland Sea.If Fucoxanthins and Diatomss existence in picophytoplankton could explain the tendency of phytoplankton to micro and miniaturization,these still need to be more sufficient evidence.国家自然科学基金(41076130;41206189); 南北极环境综合考察与评价专项(CHINARE2011-2015

三种检测方法对样品中沙门氏菌的检测结果比较

本实验采用VIDAS、API20E和SN0170-92三种不同的检测方法对CNCA举行的食品中常见致病菌能力验证计划中提供的一份盲样进行检验,总结对比了3种不同检验方法对沙门氏菌检测的各自优缺点

一种基于微电极的珊瑚共生体光补偿点测定方法探讨

珊瑚虫与虫黄藻互利共生形成共生体,虫黄藻通过光合作用为珊瑚虫提供重要的能量来源。珊瑚共生体的光补偿点可以较好地指示珊瑚的光适应性,是重要光合特性指标,但其测定方法鲜有报道。利用溶氧微电极结合光强可调节光源,以鹿角杯形珊瑚为实验材料,依据扩散平衡理论,建立了一种造礁石珊瑚的光补偿点的测定方法。实验结果表明珊瑚的扩散边界层溶氧浓度会快速响应光强变化。珊瑚扩散边界层溶氧浓度与光合有效辐射具有较好的相关性,且光强由高降低过程测得的相关系数更高。实验测得鹿角杯形珊瑚的光补偿点较低,为1.52μE/m~2/s,与喜阴植物的光补偿点相当。相对较低的光补偿点利于珊瑚栖居于水深范围更广的区域,有助于扩展珊瑚的生态位。溶氧微电极相关技术和方法在珊瑚光合作用研究中具有广泛的应用前景。中国科学院战略性先导科技专项A(XDA13020300)国家自然科学基金(41676163; 41406191; 41276113; 41276114)国家重点研发计划(2017YFC0506301,2018YFC1406500)广州市珠江科技新星(201806010017

Age-Related Loss of Innate Immune Antimicrobial Function of Dermal Fat Is Mediated by Transforming Growth Factor Beta

Dermal immature adipocytes fightagainstStaphylococcusaureusinfectionby secreting antimicrobial peptidesduring adipogenesis. Zhang et al.demonstrate that activation of the TGF-bpathway suppresses the adipogenicpotential of dermal fibroblasts andtherefore leads to an age-dependent lossof antimicrobial protection fromdermal fat. 皮下脂肪细胞作为皮肤的最后一道防线，有很重要的免疫抗菌功能，分化中脂肪细胞释放大量抗菌肽，这是一种人自源抗生素，能有效地抑制细菌生长。但这一重要的宿主天然免疫功能在发育和老化过程中如何被调控还不为人知。研究人员发现，老化过程中皮肤脂肪丢失是和真皮成纤维细胞（dermal fibroblasts）失去脂肪分化能力密切相关的。真皮成纤维细胞是皮肤深处的特化细胞，可以产生结缔组织并帮助皮肤从损伤中恢复。【Abstract】Dermal fibroblasts (dFBs) resist infection by locallydifferentiating into adipocytes and producing cathe-licidin antimicrobial peptide in response toStaphylo-coccusaureus(S.aureus). Here, we show thatneonatal skin was enriched with adipogenic dFBsand immature dermal fat that highly expressed cath-elicidin. The pool of adipogenic and antimicrobialdFBs declined after birth, leading to an age-depen-dent loss of dermal fat and a decrease in adipogene-sis and cathelidicin production in response to infec-tion. Transforming growth factor beta (TGF-b),which acted on uncommitted embryonic and adultdFBs and inhibited their adipogenic and antimicro-bial function, was identified as a key upstream regu-lator of this process. Furthermore, inhibition of theTGF-breceptor restored the adipogenic and antimi-crobial function of dFBs in culture and increasedresistance of adult mice toS.aureusinfection. Theseresults provide insight into changes that occur in theskin innate immune system between the perinataland adult periods of life.This work was supported by NIH grant R01-AR069653 to L.Z. and R.L.G. and NIH grants R01-AI083358, R01-AR052728, and U19-AI117673 to R.L.G. M.V.P. is supported by a Pew Charitable Trust grant, NIH grants U01-AR073159 and R01-AR067273, National Science Foundation (NSF) grant DMS1763272, and Simons Foundation grant 594598 (to Qing Nie). C.F.G.J. is supported by NSF-GRFP grant DGE-1321846 and MBRS-IMSD training grant GM055246. Y.Z. is supported by NIH grant R01-AI107027. 该项目研究得到了厦门大学双一流启动基金的支持

中国海洋生物研究70年

随着中国"海洋强国"战略的提出,加快建设海洋类学科的发展成为历史必然,海洋生物是海洋不可分割的一部分,海洋环境和生物相互依存,相互作用,海洋生物研究重要性日益凸显。为纪念中国科学家在海洋生物领域的突出贡献,本文回顾了建国以来中国海洋生物相关的重要研究进展,梳理了中国科学家在海洋生物领域的突出贡献,系统总结并讨论了未来研究方向,抛砖引玉,希望籍此助推中国海洋生物研究的新高潮。国家自然科学基金项目(41876134,41876171)中国大洋矿产资源研究开发协会专项项目(DY135-E2-5-03)教育部长江学者特聘教授项目(T2014253