大型水电站分层取水叠梁门的脉动压力特性

为减少下泄低温水对下游生态环境的影响,某水电站进水口拟采取叠梁门分层取水方式.由于过流方式不同,叠梁门与普通平板闸门在荷载特性上存在明显差别.通过模型试验对进水口叠梁门的脉动压力进行测量,结合数值模拟结果,分析了叠梁门上脉动压力的分布规律及荷载特性.结果表明:在所有工况下,作用在叠梁门不同部位的脉动压力特性不同,但均在叠梁门下游侧底部出现了较大的脉动压力;叠梁门下游侧底部大漩涡产生的脉动压力是诱发叠梁门流激振动的主要激振力.提出了一种针对叠梁门顶部过流计算激振力的简易方法,可供工程设计参考使用.     

黑龙江省松嫩平原南部人群发硒和硒摄入量研究

黑龙江曾是我国克山病和大骨节病最为严重的地区之一,该病目前虽然已经基本得到控制,但还有散在病点.为了解该地区人群硒营养状况,在松嫩平原南部27个县采集了居民主食和头发样品分析测定硒摄入量和硒营养水平.结果表明,该地区大部分人群硒日摄入量不足,约半数人群发硒含量处于硒营养状况缺乏和亚缺乏状态,建议采取补硒措施纠正.     

V8进气管金属型重力铸造计算机模拟

采用Anycasting模拟软件对进气管金属型重力铸造进行充型和凝固模拟分析,比较了单边底注和双边底注浇注方案的影响。结果表明,单边底注浇注填充状态比较理想,补缩通道顺畅,基本消除了缩孔、缩松缺陷。     

大鼠5周高住低练减体重效果研究

将24只雄性SD大鼠随机分为常氧安静组（Ⅰ组）、低住低练组（Ⅱ组）、间歇低氧安静组（Ⅲ组）、高住低练组（Ⅳ组）,进行5周训练.采用称量法测定大鼠体重、食物摄入量,大鼠肾周、附睾脂肪垫及腓肠肌重量.5周末Ⅳ组大鼠体重低于Ⅰ、Ⅲ组（P〈0.05）和Ⅱ组（P〉0.05）,体重增幅低于其他各组（P〈0.05）.Ⅳ组大鼠脂肪垫总量低于Ⅲ组（P〈0.05）和Ⅰ组（P〉0.05）,腓肠肌重量高于Ⅲ组（P〈0.05）和Ⅰ组（P〉0.05）.试验中Ⅳ组大鼠食物摄入总量较其他各组大鼠低.5周高住低练具有良好的减体重效果,高住低练过程中食物摄入量减少是大鼠体重下降的一个重要因素.     

Elemental Analysis and Nutritional Value of Seaweed from the East Coast of KwaZulu-Natal,South Africa

Seaweed, biologically and phycologically referred to as algae, is classified as Rhodophyta (red), Chlorophyta (green), and Ochrophyta (brown). In this study, the concentrations of 13 elements (As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Se, and Zn) were investigated for 14 seaweed species of varying classes (Amphiroa bowerbankii, Ceramium virgatum, Dichotomaria tenera, Ellisolandia (Coralline) elongata, Gelidium abbottiorum, Gracilaria canaliculata, Jania rubens, and Jania (Haliptylon) squamata of the Rhodophyta (red); Caulerpa filiformis, Codium capitatum, Halimeda cuneata, and Ulva rigida of the Chlorophyta (green); and Cystoseira myrica and Sargassum elegans of the Ochrophyta (brown) to determine the nutritional value of seaweed based on its medicinal properties, industrial importance, and natural abundance. The elemental distribution in seaweeds was in decreasing order of Ca?>?Mg?>?Fe?>?Cu?>?Mn?>?Zn?>?Cr?>?Co?>?Se?>?As?>?Pb?>?Ni?>?Cd. All edible species contained high levels of macro and microelements with the corali sp. accumulating high levels of Ca. Of the edible seaweeds characterized, only three (G. abbottiorum, E. (Coralline) elongate and C. virgatum) are suitable for human consumption due to high levels of As, Cd, and Pb present in the other species. These three species are also rich in essential nutrients, specifically C. virgatum, which is high in Cu and Se. Hierarchical cluster analysis showed a clear similarity in distribution of essential and toxic elements in similar classes of seaweed.     

Presence of multiple peripheral circadian oscillators in the tissues controlling voiding function in mice

Circadian clocks are the endogenous oscillators that harmonize a variety of physiological processes within the body. Although many urinary functions exhibit clear daily or circadian variation in diurnal humans and nocturnal rodents, the precise mechanisms of these variations are as yet unclear. In the present study, we demonstrate that Per2 promoter activity clearly oscillates in neonate and adult bladders cultured ex vivo from Per2::Luc knock-in mice. In subsequent experiments, we show that multiple local oscillators are operating in all the bladder tissues (detrusor, sphincter and urothelim) and the lumbar spinal cord (L4–5) but not in the pontine micturition center or the ventrolateral periaqueductal gray of the brain. Accordingly, the water intake and urine volume exhibited daily and circadian variations in young adult wild-type mice but not in Per1^−/−Per2^−/− mice, suggesting a functional clock-dependent nature of the micturition rhythm. Particularly in PDK mice, the water intake and urinary excretion displayed an arrhythmic pattern under constant darkness, and the amount of water consumed and excreted significantly increased compared with those of WT mice. These results suggest that local circadian clocks reside in three types of bladder tissue and the lumbar spinal cord and may have important roles in the circadian control of micturition function.     

金华市地氟病病区摄氟总量调查

金华地区氟污染严重,地氟病病区居民摄氟总量偏高,平均日摄入量可达4.77 mg。饮水和食物是主要的摄氟途径。应该采用综合性的地氟病防治措施,仅仅靠改水是不够的。     

Assessing Human Exposure to Organic Pollutants in the Indoor Environment

There is an ongoing probing of the role of chemicals in the indoor environment. The majority of potential target substances are so‐called very volatile, volatile, and semi‐volatile organic compounds (VVOCs, VOCs, and SVOCs). Depending on their physical properties and the mass transfer conditions, they are distributed in or between the gas phase, particle phase, settled house dust, surface films, clothing, and other fabrics as well as the exposed skin and hair of the occupants themselves. Therefore, inhalation, ingestion, and dermal uptake all must be considered as relevant pathways for exposure assessment in human habitats. Exposure to VVOCs, VOCs, and SVOCs can be estimated by measuring their concentrations in relevant indoor compartments or by determining the amounts of the target compounds and/or their metabolites in urine and blood. Assessing the various routes of exposure often requires a combination of sophisticated and interdisciplinary theoretical background and experimental techniques. Consequently, close communication and collaboration between chemical and exposure scientists are needed to achieve a better understanding of human exposure to chemical substances in various indoor environments. Embedded in the toxicological context, this is the basis for assessing the corresponding health risks and for determining control strategies or approaches to limit such risks.     

进气门晚关与高压缩比技术在汽油机上的应用

针对混合动力汽车用发动机的特点,通过模拟和试验相结合的方法,研究了进气门晚关与高压缩比对汽油机部分负荷性能的改善作用以及由于发动机参数变化对外特性的影响.研究结果表明:部分负荷应用进气门晚关与高压缩比可在排放变化不大的前提下使发动机油耗降低4%~10%;进气门晚关控制负荷有效降低了泵气损失,配合几何压缩比的提高和点火提前角的优化,实现了较好的燃烧性能,提高了膨胀比;综合作用下使得有效热效率提高;较长进气持续期和较大几何压缩比的应用使得外特性扭矩降低2%~5%的同时,油耗平均5%.     

基于智能化分时区间采集技术的液相色谱-串联质谱法测定全血中磷脂酰乙醇及人群水平调查

磷脂酰乙醇是具有潜在临床应用价值的酒精摄入生物学标志物,准确测定其含量可以为酒精摄入监测提供客观、量化的重要参考依据。本研究建立了一种基于智能化分时区间采集技术的液相色谱-串联质谱分析方法,能够同时实现对人全血样品中18种磷脂酰乙醇的准确测定。采用甲醇-甲基叔丁基醚-水作为萃取体系,选用XBridge C18色谱柱,以2.5 mmol/L乙酸铵异丙醇溶液和2.5 mmol/L乙酸铵水溶液-乙腈（50∶50, v/v）为流动相进行梯度洗脱,采用电喷雾离子源、智能化分时间段-负离子多反应选择离子监测模式。经验证,该方法线性关系良好,相关系数≥0.9998,线性范围在10~2500 ng/mL之间,检出限和定量限分别为0.7~2.8 ng/mL、2.2~9.4 ng/mL,加标回收率在91.0%~102.2%之间,日内精密度和日间精密度在0.4%~7.4%之间。该方法简便、快速、精密,智能化分时区间采集方法为每个离子通道分配合适的扫描时间段,增加了每个目标物离子通道的有效采集时长,提高了各目标分析物的信号响应,从而实现了对人全血样本中18种磷脂酰乙醇的有效分析测定。使用本方法测定了359名有规律饮酒习惯的志愿者全血样本,样本中的总磷脂酰乙醇含量范围为51.13 ng/mL~2.89 μg/mL,平均为363.16 ng/mL。磷脂酰乙醇16∶0/18∶1、16∶0/18∶2是两个丰度最大的同系物,平均含量分别为74.21和48.75 ng/mL,各约占总量的20.43%和13.42%。Spearman相关性分析结果显示,磷脂酰乙醇之间相关性良好,并与临床现有酒精生物学标志物γ-谷氨酰转肽酶呈正相关;同时磷脂酰乙醇与肝肾功能相关临床生化指标显著相关。所建方法可以准确、精密检测人血磷脂酰乙醇含量,能够客观、可靠、量化反映人体酒精摄入状况,并可为临床酒精摄入监测提供有潜在应用价值的分析手段。