温带荒漠中温度和土壤水分对土壤呼吸的影响

荒漠对气候变化具有高度敏感性,深刻认识和量化非生物因子对荒漠生态系统土壤呼吸的影响具有重要意义。采用自动CO2通量系统(Li-8100)监测了梭梭(Haloxylon ammodendron)、假木贼(Anabasis aphylla)和盐穗木(Halostachys caspica)群落生长季土壤呼吸及温度、土壤含水量等,深入分析了水热因子对土壤呼吸的影响。土壤呼吸具有不对称的日格局,最小值出现在8:00,最大值在12:00～14:00。土壤呼吸的季节格局与气温变化基本同步,最小值在生长季末期(10月),最大值在生长季中期(6～7月)。梭梭、假木贼和盐穗木群落生长季平均土壤呼吸速率分别为0.76、0.52和0.46μmol CO2·m-2·s-1。气温对假木贼(51%)和盐穗木群落(65%)土壤呼吸季节变化的解释率高于梭梭(35%)。梭梭、假木贼和盐穗木群落土壤呼吸温度敏感性(Q10)逐渐增大,基础呼吸速率(R10)逐渐减小。剔除温度影响后,梭梭、假木贼群落土壤呼吸与土壤含水量呈显著的幂二次方函数关系,盐穗木群落两者关系却明显减弱,未达到显著水平。气温、土壤含水量的二元方程均能解释群落土壤呼吸大部分的时间变异:梭梭群落71%～93%、假木贼群落79%～82%、盐穗木群落70%～80%。人工模拟降水后土壤呼吸速率表现出降水后10min减小、180min时明显增加、达到最大值后再次衰减的现象。5和2.5mm降水处理下的土壤呼吸速率最大值和其后的递减值高于对照处理,土壤呼吸增加、达到峰值和其后递减过程与5cm土壤温度变化基本同步

FEC基电解液对高压正极材料Li2CoPO4F电化学性能的影响

本文研究了以氟代碳酸乙烯酯FEC（fluoroethylene carbonate）为共溶剂的电解液对高压正极材料Li2CoPO4F电化学性能的影响,与碳酸酯基电解液1 mol·L-1LiPF6EC/DMC=1:1（m:m）相比,1 mol·L-1LiPF6FEC/DMC=1:1（m:m）可显著提高Li2CoPO4F的循环稳定性.通过线性扫描伏安法（LSV）、扫描电镜（SEM）、X射线光电子能谱（XPS）、X射线衍射（XRD）结合电化学阻抗（EIS）对FEC改善Li2CoPO4F材料循环稳定性的机理进行了探索,结果表明与传统碳酸酯基电解液相比,FEC基电解液在高压下有着优异的抗氧化性,能够有效抑制电解液的氧化分解.同时,FEC基电解液中形成的表面膜具有更高的稳定性,能够抑制电极/电解液界面副反应的发生,提高循环过程中电极材料结构稳定性,从而有益于提高Li2CoPO4F材料的电化学性能.福建省自然科学基金项目(No.2014J05019);;国家自然科学基金项目(No.21233004,No.21303147);;厦门大学校长基金(No.20720150090)资

Preliminary exploration of the experiments teaching reform on water quality monitoring and evaluation course for preventive medicine majors

水质监测与评价是预防医学专业实验教学的重要组成部分,熟悉并掌握水质监测与评价的方法与流程,对于本专业学生毕业后从事疾病预防控制、卫生监督等工作具有举足轻重的作用。针对目前国内水质监测与评价实验教学中存在的问题,通过增加现场教学环节、拓展实验教学内容以及强化实验教学管理与分析质量控制等改革措施,将实验教学与校园环境监测紧密结合起来,以激发学生学习的积极性和主动性,培养学生独立思考问题、分析问题和解决问题的能力,进而为全面提高实验教学质量进行了有益的探索与尝试。Water quality monitoring and evaluation is an important part of experimental teaching for preventive medicine majors.Familiarizing with and mastering the methods and procedures of water quality monitoring and evaluation is crucial for students engaging in disease prevention and control or health supervision after graduation.Aiming at solving the existing problems in experimental teaching of water quality monitoring and evaluation, a series of reformative measures, including increasing the frequency of field experimental teaching, expanding the contents of experimental teaching, strengthening the management of experimental teaching, and analyzing quality control, were implemented; and experiment teaching was combined with monitoring of the campus environment.These measures aimed to stimulate students' initiative to learn, cultivate students' independent thinking and problem analyzing and solving skills, and therefore provide useful exploration and trials in comprehensively improving the quality of experimental teaching

Research progress of high voltage electrolyte for lithium-ion batteries

随着对锂离子电池能量密度要求的提高,新一代高电压锂离子电池和与之匹配的高电压电解液的研究开发也日益受到重视。从优化电解液的组成和使用具有特殊功能的新型溶剂、添加剂等方面对锂离子电池高电压电解液的研究进行分析和总结,并对未来的应用前景进行展望。With the increasing requirements for the lithium-ion battery energy density, more and more attentions are focused on the research and development of a new generation of high voltage lithium-ion battery and high voltage electrolyte.The recent research progress related to high voltage electrolyte solutions was analyzed and summarized from the electrolyte composition, special solvent and additives

Synthesis and Bioactivity of 5-Ivermectin B_(1a) Esters

依维菌素B1a与羧酸在DMAP/DCC体系中直接酯化 ,得到 10个 5 IVB1a酯衍生物 ,产率 6 6 %～ 82 %;它们的化学结构得到IR ,1HNMR ,13 CNMR和MS谱的确证 .它们具有良好的杀虫、杀螨活性 .Ten 5-Ivermectin B 1a ester derivatives were prepared from Ivermectin B 1a and carboxylic acids in the systems of DCC/DMAP. Their chemical structures were determined by IR, 1H NMR, 13C NMR and MS spectra. The preliminary results of bioassay showed that L-1～L-10 have good insecticidal activities.国家自然科学基金(No .2 9832 0 5 0 )资助项

A preliminary study on the induction of spawning by sex pheromones in Bostrichthys sinensis

在陶瓷人工产卵管道内吊挂性外激素的研究表明,卵巢提取液对雄鱼的吸引作用大于雌鱼,而精巢和贮精囊提取液对雌鱼的吸引作用则大于雄鱼,17α-P、17α,20β-P和PGE2对雌鱼和雄鱼均具有相似的吸引作用。雌鱼在管道内的产卵次数、产卵量以及成熟卵的受精率均与产卵管道内吊挂的性外激素种类有关,17α,20β-P和PGE2两个实验组产卵次数最多,其中PGE2实验组的产卵量和受精率最高。17α-P在贮精囊和精巢提取液中的含量显著高于卵巢提取液(P精巢提取液>卵巢提取液。卵巢提取液刺激雄鱼所引起的平均EOG高于雌鱼,而精巢和贮精囊提取液刺激雌鱼所引起的平均EOG高于雄鱼,雌鱼和雄鱼对17α-P、17α,20β-P、PGE2和PGF2α刺激所产生的平均EOG,以PGE2为最高。The results obtained from fixing sex pheromones to the inside surface of the artificial ceramic spawning nests showed that ovarian extract attracted more males than females to enter the nests, while testis extract and seminal vesicle extract attracted more females than males. 17α-P, 17α, 20β-P and PGE_2 were equally effective in attracting both females and males. Spawning frequencies and the spawned egg number of females as well as fertilization rates were related to different kinds of sex pheromones. The most spawning frequencies were found in both 17α, 20β-P and PGE_2 treated groups. The greatest spawned egg number and the highest fertilization rate were observed in PGE_2 group. The levels of 17α-P in seminal vesicle extract and testis extract were significantly higher (Ptestis extract>ovarian extract. The mean EOG, stimulated by ovarian extract, was higher in males than in females, whereas the mean EOGs, stimulated by testis or seminal vesicle extract, were higher in females than in males. The mean highest EOG of both females and males in response to 17α-P,17α, 20β-P,PGE_2 and PGF_(2α) was observed in PGE_2 group.国家自然科学基金资助项目(40276040

Occurrence and Distribution of Organotin Compounds in Thais clavigera from Xiamen Coast

采用戊基化格式衍生法,gC-fPd分析了厦门港周边海域9个小岛屿分布的疣荔枝螺(THAIS ClAVIgErA)体内3种丁基锡化合物(buTylTInS)和3种苯基锡化合物(PHEnylTInS)的存在形态与分布特征.结果表明,丁基锡化合物总浓度(ΣbTS)为0.3~70.6ng.g-1,平均值为28.8ng.g-1,以一丁基锡化合物(MbT)为主.苯基锡化合物总浓度(ΣPHTS)为nd~18.8ng.g-1,平均值为7.9ng.g-1,以三苯基锡化合物为主.厦门港周边海域以丁基锡化合物为主要污染物,占到总有机锡化合物(ΣOTS)的74.3%~96.8%.疣荔枝螺体内(ΣbTS)和(ΣPHTS)呈现从厦门港内到港外逐渐降低的趋势.疣荔枝螺体内TbT和TPHT的浓度显示良好的相关关系(r2=0.7109,P<0.01),说明TPHT和TbT来源趋同,即来源于船舶防污涂料,或水产养殖污染源.与我国东南沿海港口相比,厦门海域疣荔枝螺体内丁基锡化合物的污染处于一个较低水平但比2002年有所加重.Occurrence and distribution of 6 organotin compounds including butyltin and phenyltin species were detected in Thais clavigera which were collected from 9 coastal areas sites around Xiamen Coast,by pentylized derivatization,GC-FPD.Results indicated that all Thais clavigera samples were contaminated with organotin compounds.The concentrations in Thais clavigera soft bodies varied from 0.3 to 70.6 ng.g -1 with a mean value of 28.8 ng.g -1 for butyltin compounds,and from nd to 18.8 ng.g -1 with a mean value of 7.9 ng.g -1 for phenyltin compounds,respectively.MBT and TPhT were high levels in butyltin compounds and phentyltin compounds,respectively.In addition,butyltin compounds were the dominant contaminates in all samples with high percentage from 74.3% to 96.8%.There was a significant correlation between TBT and TPhT (R2 = 0.710 9,p < 0.01).This result showed that both TBT and TPhT came from antifouling paints for ships or for mariculture nets.Compared with those data reported from the other regions around southeast coast of China,present study reveals that contaminated level of organotin compounds in Thais clavigera are relatively lower in Xiamen Coast.But it is higher than those in 2002.国家自然科学基金项目(40476048;20777060

骨髓间充质细胞联合PDMS支架构建移植胰岛微环境的实验研究

目的为了提高移植胰岛的活性和功能,构建适合移植胰岛生存的微环境。方法采用聚二甲基硅氧烷(PDMS)和氯化钠晶体构建三维支架,联合骨髓间充质细胞(MSCs)、纤维蛋白和胰岛共同构建迷你\"人工胰腺\"。采用链脲佐菌素(STZ)诱导的糖尿病大鼠移植模型评价效果,将\"人工胰腺\"移植到糖尿病大鼠大网膜内,对照组行假手术,术后隔天监测移植大鼠血糖水平;数据采用t检验和曼-惠特尼U检验。结果用PDMS构建的三维巨孔支架,支架内可见大量不规则孔洞空间。胰岛和MSCs可成功装载入支架内,HE染色结果显示,支架孔内存在胰岛,胰岛周围包绕有MSCs。糖尿病大鼠大网膜内移植结果显示,移植后各时间点(1,3,5,7 d),\"人工胰腺\"移植组糖尿病大鼠血糖水平分别为(278.70±86.06) mg/dl、(323.50±44.29) mg/dl、(283.30±74.00) mg/dl、(304.80±13.33) mg/dl,较假手术对照组(606.00±52.40) mg/dl、(589.70±55.78) mg/dl、(615.00±54.84) mg/dl、(630.30±48.17) mg/dl均降低,差异具有统计学意义(t=7.96、9.15、8.82,U=0.00,P均<0.01)。结论 MSCs联合PDMS三维支架构建的微环境,可为移植胰岛提供生存的环境,为临床开展胰岛移植提供新的策略

Imposex of Thais clavigera and Cantharus cecillei in the coastal waters of Xiamen

海产腹足类性畸变以其对有机锡的敏感性、特异性和不可逆性而成为海洋有机锡污染的理想指示种。调查研究了厦门海域岩相海岸带疣荔枝螺(THAIS ClAVIgErA)和甲虫螺(CAnTHAruS CECIllEI)的性畸变情况,通过生物学指标IOI(性畸变率)、rPSI(相对阴茎发展指数)、VdSI(输精管发展指数)及SrI(性比指数)综合评价其性畸变发展程度,间接指示厦门周边海域的有机锡污染程度。研究结果发现,在采集疣荔枝螺的17个站点中有5个站点种群性畸变率为100%,其中宝珠屿种群性畸变程度最为严重,VdSI达4,采集甲虫螺的4个站点的种群性畸变率均为100%。性畸变程度较严重的种群普遍集中于厦门西港,并且表现出由港内到港外逐渐减轻的趋势,而白城、会展中心和大嶝岛等位于开阔的厦门东海域的种群性畸变程度最轻,与往年厦门西海域有机锡污染监测数据相比一致,体现出性畸变程度与有机锡污染程度及海港码头远近之间的相互关系。The degree of imposex,i.e.the imposition of male characteristics onto females,in neogastropods can be used as a sensitive and accurate biomarker to evaluate organotin contamination in coastal marine environment.Now,the imposex status in females of Thais clavigera and Cantharus cecillei in 17 sites was investigated to evaluate the organotin contamination along Xiamen Bay during 2006 and 2007.The four indices including incidence of imposex(IOI),relative penis size index(RPSI),vas deferens sequences index(VDSI) and sex ratio index(SRI) were used comprehensively to assess the imposex status in order to ascertain the extent of organotin bioavailability in Xiamen Bay.Based on this research,T.clavigera in 5 sites and C.cecillei in all survey sites exhibited the IOI of 100%.At Bao ZhuYu Islet,the imposex level was the most serious with maximum VDSI value of 4.In general,the imposex level decreased from the inner to the outer of Xiamen Western Harbour,and the populations in the open Xiamen Eastern Waters including Bai Cheng,Convention and Exhibiton Center and Dadeng Island showed a lower imposex level.These results were accordant with the concentrations of organotins in 2005.The imposex degree also increased with increasing organotin contamination and decreasing distance from shipping facilities.国家自然科学基金资助项目(40476048);厦门大学近海海洋环境科学国家重点实验室开放基金资助项目;厦门大学新世纪优秀人才计划基金资助项

Synthesis and bioactivity of 5-Ivermectin B-1a esters

Ten 5-Ivermectin B-1a ester derivatives were prepared from Ivermectin B-1a and carboxylic acids in the systems of DCC/DMAP. Their chemical structures were determined by IR, H-1 NMR, C-13 NMR. and MS spectra. The preliminary results of bioassay showed that L-1 similar to L-10 have good insecticidal activities