犬囊状动脉瘤模型的制作

本文报道用“静脉囊镶嵌技术·制成犬的囊状动脉瘤模型。18个模型(6个单侧型,6个分叉型,6个末梢型)造型后2周经IA DSA检查。本模型在分型、血流动力学改变方面与人类囊状脑动脉瘤类似。不同类型的动脉瘤模型既有相同的血流动力学特征,又有各自的特点,这与动脉瘤与载瘤动脉的角度有关。我们认为该模型可应用于研究动脉瘤的血流动力学与血管内栓塞治疗。     

Reproductive biology of guitar,Rhinobatos hynnicephalus

Synopsis Reproductive biology of the guitarfish,Rhinobatos hynnicephalus, from Xiamen coastal waters is described. Males have two functional testes. Spermatogenic cells in different seminiferous follicles are at different developmental stages while those in the same follicle are at the same stage. The development of claspers suggests that males mature at 380–400 mm TL. Females mature at 390–440mm TL. Both ovaries are functional. The first generation of ovarian eggs reach mature size when 22–24mm in diameter in April or May. The subsequent crop of eggs is ready for ovulation when the intrauterine embryos reach full term. The guitarfish is aplacentally viviparous. Longitudinal folds were observed on the internal wall of the uterus. Gestation takes one year and parturition takes place in June or July. Fecundity ranges from 2 to 9, with the large females usually being more fecund. Of 29 embryos ranging from 52–157mm TL, there were 15 females and 14 males indicating an embryonic sex ratio 1:1.     

Marginal proportional hazards models for clustered interval-censored data with time-dependent covariates

The Botswana Combination Prevention Project was a cluster-randomized HIV prevention trial whose follow-up period coincided with Botswana's national adoption of a universal test and treat strategy for HIV management. Of interest is whether, and to what extent, this change in policy modified the preventative effects of the study intervention. To address such questions, we adopt a stratified proportional hazards model for clustered interval-censored data with time-dependent covariates and develop a composite expectation maximization algorithm that facilitates estimation of model parameters without placing parametric assumptions on either the baseline hazard functions or the within-cluster dependence structure. We show that the resulting estimators for the regression parameters are consistent and asymptotically normal. We also propose and provide theoretical justification for the use of the profile composite likelihood function to construct a robust sandwich estimator for the variance. We characterize the finite-sample performance and robustness of these estimators through extensive simulation studies. Finally, we conclude by applying this stratified proportional hazards model to a re-analysis of the Botswana Combination Prevention Project, with the national adoption of a universal test and treat strategy now modeled as a time-dependent covariate.     

朱鹮肠道微生物多样性与产酶活性

【背景】朱鹮是我国国家一级保护动物,属于世界上最濒危的鸟类之一。对朱鹮肠道微生物的多样性和产胞外酶活性进行分析,可为朱鹮种群数量恢复提供思路。【目的】了解朱鹮肠道微生物的多样性,测定其产胞外酶活性。【方法】采用纯培养的方法获得朱鹮肠道微生物,通过革兰氏染色和生理生化鉴定,结合16S rRNA基因扩增和序列分析对细菌进行鉴定。使用水解圈法筛选产淀粉酶、蛋白酶、纤维素酶、脂肪酶的菌株。【结果】从人工喂养的朱鹮新鲜粪便中共分离到296株细菌,共计2个门11个属。变形菌门(Proteobacteria) 236株,占分离总数的79.73%,分别为：埃希氏菌属(Escherichia) 137株,占分离总数的46.28%;哈夫尼亚菌属(Hafnia) 39株,占分离总数的13.18%;变形菌属(Proteus) 28株,占分离总数的9.46%;柠檬酸杆菌属(Citrobacter) 23株,占分离总数的7.77%;气单胞菌属(Aeromonas) 6株,占分离总数的2.03%;肠杆菌属(Enterobacter) 1株,占分离总数的0.34%;志贺菌属(Shigella) 1株,占分离总数的0.34%;克雷伯菌属(Klebsiella) 1株,占分离总数的0.34%。厚壁菌门(Firmicutes) 60株,占分离总数的20.27%,分别为：肠球菌属(Enterococcus) 33株,占分离总数的11.15%;库特氏菌属(Kurthia) 14株,占分离总数的4.73%;芽孢杆菌属(Bacillus) 13株,占分离总数的4.39%。优势菌群为变形菌门(Proteobacteria)中的埃希氏菌属(Escherichia),占细菌总数的46.28%。经过生理生化鉴定,每个菌株生理生化鉴定出的种属与各自的16S rRNA基因鉴定出的种属相一致。产酶活力分析结果显示有238株产蛋白酶、25株产脂肪酶、24株产淀粉酶、15株产纤维素酶,分别占分离总数的80.41%、8.45%、8.11%和5.07%。【结论】朱鹮肠道微生物分离出的细菌可分为2门11属,优势菌群为变形菌门(Proteobacteria)中的埃希氏菌属(Escherichia),占细菌总数的46.28%;产酶活性分析显示,80.41%的菌株具有产蛋白酶能力。     

北京东灵山地区植物群落多样性研究 Ⅹ.不同尺度下群落样带的β多样性及分形分析

选取不同尺度,采用β多样性指数和分形分析方法对东灵山暖温带森林样带上群落多样性随海拔梯度的空间变异规律进行了研究。结果表明,１）Ｃｏｄｙ指数揭示出乔木层在取样尺度２０ｍ和灌木层在取样尺度８０ｍ时,随海拔梯度变化呈明确的物种替代规律性;乔木层和灌木层在同一地点的物种替代速率具有互补性;群落多样性的空间变异在样带的起始（山底）和终止（山顶）地段较高。２）笔者提出的群落结构变异（ＣｏｍｍｕｎｉｔｙＳｔｒｕｃｔｕｒｅＶａｒｉａｔｉｏｎ,ＣＳＶ）指数介于０～１之间,作为Ｃｏｄｙ指数的改进,它对群落多样性沿环境梯度变化的揭示更接近于实际情况;ＣＳＶ指数分析显示乔木层在＞４０ｍ取样尺度,灌木层＞２０ｍ取样尺度群落结构出现明确变异规律;物种丰富度（Ｃｏｄｙ指数）和群落结构（ＣＳＶ指数）变化规律性的表现尺度（取样尺度）不同。３）分形分析的结果,乔木主林层在２００ｍ内不同尺度间不存在相关规律,乔木更新层只在＜４０ｍ尺度显示出尺度依赖性,灌木层的尺度依赖特征则表现为小尺度变异显著而较大尺度上变异程度降低;乔木更新层与灌木层的异质性规律发生显著变化（拐点）的尺度不同,分别为４０ｍ和９０～１００ｍ。同时,还对群落学研究中的取样尺度问题进行了探讨。     

氦氖激光对绵羊精清中酶活性效应的研究

本文研究结果表明低剂量的氦氖激光可以提高绵羊精清中GOT和LDH酶的活性,并对其机制作了初步的探讨。     

High‐Temperature Shock Enabled Nanomanufacturing for Energy‐Related Applications

Functional nanomaterials are playing a crucial role in the emerging field of energy‐related devices. Recently, as a novel synthesis method, high‐temperature shock (HTS), which is rapid, low cost, eco‐friendly, universal, scalable, and controllable, has provided a promising option for the rational design and synthesis of various high‐quality nanomaterials. In this report, the HTS technique, including the equipment setup and operating principle, is systematically introduced, and recent progress in the synthesis of nanomaterials for energy storage and conversion applications using this HTS method is summarized. The growth mechanisms of nanoparticles and carbonaceous nanomaterials are thoroughly discussed, followed by the summary of the characteristic advantages of the HTS strategy. A series of nanomaterials prepared by the HTS method, including carbon‐based films, metal nanoparticles and compound nanoparticles, show high performance in the diverse applications of storage energy batteries, highly active catalysts, and smart energy devices. Finally, the future perspectives and directions of HTS in nanomanufacturing for broader applications are presented.     

Loci and candidate gene identification for soybean resistance to Phytophthora root rot race 1 in combination with association and linkage mapping

Molecular Breeding - Northern corn leaf blight (NCLB) is one of the main diseases of maize, which greatly reduces production and causes millions of dollars in losses worldwide annually....     

Overexpression of the persimmon abscisic acid β‐glucosidase gene (DkBG1) alters fruit ripening in transgenic tomato

β‐Glucosidases (BG) are present in many plant tissues. Among these, abscisic acid (ABA) β‐glucosidases are thought to take part in the adjustment of cellular ABA levels, however the role of ABA‐BG in fruits is still unclear. In this study, through RNA‐seq analysis of persimmon fruit, 10 full‐length DkBG genes were isolated and were all found to be expressed. In particular, DkBG1 was highly expressed in persimmon fruits with a maximum expression 95 days after full bloom (DAFD). We verified that, in vitro, DkBG1 protein can hydrolyze ABA‐glucose ester (ABA‐GE) to release free ABA. Compared with wild‐type, tomato plants that overexpressed DkBG1 significantly upregulated the expression of ABA receptor PYL3/7 genes and showed typical symptoms of ABA hypersensitivity in fruits. DkBG1 overexpression (DkBG1‐OE) accelerated fruit ripening onset by 3–4 days by increasing ABA levels at the pre‐breaker stage and induced early ethylene release compared with wild‐type fruits. DkBG1‐OE altered the expression of ripening regulator NON‐RIPENING (NOR) and its target genes; this in turn altered fruit quality traits such as coloration. Our results demonstrated that DkBG1 plays an important role in fruit ripening and quality by adjusting ABA levels via hydrolysis of ABA‐GE.     

新建川藏铁路(雅安-昌都段)沿线外来入侵植物种类及分布特征

横断山区为全球生物多样性热点地区之一, 也是全国生态屏障的重要组成部分。新建川藏铁路雅安至昌都段横跨横断山核心地区, 铁路建设形成的交通网络将沿线生物多样性热点区域与外界相连, 导致生物入侵风险陡增。为获得区域内外来入侵植物的种类及分布特征信息, 为即将开始的铁路工程建设、生态保护及生态修复等工作提供参考, 我们在雅安-昌都段内选择43个位点各进行长度1 km、宽度20 m的样线调查。研究结果显示: 雅安-昌都段共发现外来入侵植物58种, 隶属于18科42属, 其中出现频度最高的种类依次是牛膝菊(Galinsoga parviflora)、秋英(Cosmos bipinnatus)和鬼针草(Bidens pilosa)。从危害等级来看, 其中10种为恶性入侵种, 16种为严重入侵种, 8种为局部入侵种, 15种为一般入侵种, 9种为有待观察种, 超过半数种类具有明显入侵性。原产地分析结果显示美洲是该区域外来入侵植物的主要原产地。基于海拔及主要河流区段的比较研究发现: 入侵植物的种类数量呈现出明显的由东向西、由低海拔向高海拔逐渐递减的趋势, 该分布格局是环境因子和人类活动共同作用的结果。结合铁路沿线入侵现状和生境特征, 本文分析了铁路建设可能造成的外来植物入侵风险, 并针对入侵的防范提出了相应的建议。