Effects of particulate matter on the pulmonary and vascular system: time course in spontaneously hypertensive rats

Background  

This study was performed within the scope of two multi-center European Commission-funded projects (HEPMEAP and PAMCHAR) concerning source-composition-toxicity relationship for particulate matter (PM) sampled in Europe. The present study aimed to optimize the design for PM in vivo toxicity screening studies in terms of dose and time between a single exposure and the determination of the biological responses in a rat model mimicking human disease resulting in susceptibility to ambient PM. Dust in thoracic PM size-range (aerodynamic diameter <10 μm) was sampled nearby a road tunnel (RTD) using a high volume cascade impactor. Spontaneously hypertensive rats were exposed to urban dust collected in Ottawa, Canada (EHC-93 10 mg/kg of body weight; reference PM) or different RTD doses (0.3, 1, 3, 10 mg/kg of body weight) by intratracheal instillation. Necropsy was performed at 4, 24, or 48 hr after exposure.     

Differential responses to blood pressure and oxidative stress in streptozotocin-induced diabetic wistar-kyoto rats and spontaneously hypertensive rats: effects of antioxidant (honey) treatment

Oxidative stress is implicated in the pathogenesis and/or complications of hypertension and/or diabetes mellitus. A combination of these disorders increases the risk of developing cardiovascular events. This study investigated the effects of streptozotocin (60 mg/kg; ip)-induced diabetes on blood pressure, oxidative stress and effects of honey on these parameters in the kidneys of streptozotocin-induced diabetic Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). Diabetic WKY and SHR were randomized into four groups and received distilled water (0.5 mL) and honey (1.0 g/kg) orally once daily for three weeks. Control SHR had reduced malondialdehyde (MDA) and increased systolic blood pressure (SBP), catalase (CAT) activity, and total antioxidant status (TAS). SBP, activities of glutathione peroxidase (GPx) and glutathione reductase (GR) were elevated while TAS was reduced in diabetic WKY. In contrast, SBP, TAS, activities of GPx and GR were reduced in diabetic SHR. Antioxidant (honey) treatment further reduced SBP in diabetic SHR but not in diabetic WKY. It also increased TAS, GSH, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio, activities of GPx and GR in diabetic SHR. These data suggest that differences in types, severity, and complications of diseases as well as strains may influence responses to blood pressure and oxidative stress.     

热电厂反渗透系统污堵原因解析及处理

某热电厂保安过滤器滤芯更换频繁,一级反渗透系统污堵较快.通过检查及分析,系统预处理未进行有效杀菌导致水体内微生物滋生是系统污堵的主要原因.现场采取调节杀菌剂加药量、增设分段杀菌装置及系统整体灭活等处理措施,取得了较好的效果.     

Lipid alterations and their reversion in the central nervous system of growing rats deficient in essential fatty acids

Essential fatty acid (EFA) deficiency modifies several biological parameters, i.e., growth, metabolic rate and water balance and induces functional changes in liver, kidney and lung tissues. The brain fatty acid changes reported in the literature are generally smaller than those observed in other tissues. However, EFA deficiency initiated in rats prior to birth and continued for a prolonged period of time results in decreased brain weight, brain lipid and phospholipid content and in considerable changes in polyunsaturated fatty acid distribution, especially in the ethanolamine phosphoglyceride fraction. The unsaturation level of this phospholipid is maintained at a constant level in spite of the fatty acid distribution changes. Brain lipid analyses, carried out at various time intervals in EFA deficient animals, indicate that brain weights are already reduced in 10-day-old deficient rats, that brain phospholipids decrease, especially in the males after three months, and that fatty acid distribution changes begin rather early. The latter consist of a decrease of tetraenes and increase of trienes and of the triene-tetraene ratios as early as at 10 days, a decrease of hexaenes after six months, and after six months, an increase of pentaenes, which are elevated at birth but usually disappear after three months of age. Similar changes are observed in myelin. The induced changes are not completely reversed upon return to normal diet. One of five papers to be published from the Symposium “Lipid Transport,” presented at the AOCS Meeting, New Orleans, April 1970. On leave of absence from the Department of Biochemistry, Medical School of the University of Mississippi, Jackson, Mississippi, Research Career Development Awardee (6-K3-HE-18, 345), National Heart Institute of U.S. Public Health Service.     

Effects of acidic polysaccharides from gastrodia rhizome on systolic blood pressure and serum lipid concentrations in spontaneously hypertensive rats fed a high-fat diet

The effects of acidic polysaccharides purified from Gastrodia rhizome on blood pressure and serum lipid levels in spontaneously hypertensive rats (SHR) fed a high-fat diet were investigated. Acidic polysaccharides were purified from crude polysaccharides by DEAE-Sepharose CL-6B. Thirty-six male SHR were randomly divided into three groups: Gastrodia rhizome crude polysaccharide (A), acidic polysaccharide (B) groups, and a control group (C). A 5-week oral administration of all treatment groups was performed daily in 3- to 8-week-old SHRs with a dose of 6 mg/kg of body weight/day. After 5 weeks of treatment, total cholesterol in the acidic polysaccharide group, at 69.7 ± 10.6 mg/dL, was lower than in the crude polysaccharide group (75.0 ± 6.0 mg/dL) and the control group (89.2 ± 7.4 mg/dL). In addition, triglyceride and low-density lipoprotein cholesterol levels in the acidic polysaccharide group were lower than in the crude polysaccharide and control groups. The atherogenic index of the acidic polysaccharide group was 46.3% lower than in the control group. Initial blood pressure after the initial three weeks on the high-fat diet averaged 195.9 ± 3.3 mmHg among all rats. Compared with the initial blood pressure, the final blood pressure in the control group was increased by 22.8 mmHg, whereas it decreased in the acidic polysaccharide group by 14.9 mmHg. These results indicate that acidic polysaccharides from Gastrodia rhizome reduce hypertension and improve serum lipid levels.     

浅谈MRI诊断在中枢神经系统血管炎患者中的应用

目的对于MRI诊断在中枢神经系统血管炎患者中的应用进行探讨。方法 2007年12月至2010年12月某医院收治的中枢神经系统血管炎患者,共选取10例,男6例,女4例,年龄为20～40岁,平均年龄为31.25岁,10例均行常规MRI平扫、增强及MRA检查。结果 10例均有异常MRI表现。其中6例为单侧病变,4例为双侧病变。结论 MRI诊断为临床诊断和观察疗效提供可靠依据,对治疗和估计预后亦有重要价值,对临床疑有中枢神经系统血管炎的患者,MRI可成为常规及首选检查方法。     

Neurophysiological Effects of Naturally Occurring Defensive Compounds on the Freshwater Snail Planorbis corneus: Comparison with Effects in Insects

The essential oil constituents citral, geraniol, and eugenol have toxic or repellent properties that are utilized by a variety of organisms to deter natural enemies. Their mechanism of action is unknown, but some essential oils such as eugenol are claimed to act on insects by specific binding to octopamine receptors. We studied their effects on the isolated buccal ganglia of Planorbis corneus, having demonstrated that they caused cessation of feeding and death when added to the aquarium water (approximately 5 x 10(-4) mol l(-1)). They abolished spike activity at 2 x 10(-3) mol l(-1) but at lower doses (threshold 5 x 10(-5) mol l(-1)) they resembled octopamine in eliciting burst firing indicative of the fictive feeding sequence. However, the octopamine antagonists phentolamine (10(-5) mol l(-1)), yohimbine (10(-4) mol l(-1); which blocked hyperpolarizing octopamine responses), and metoclopramide (10(-4) mol l(-1); which blocked depolarization) had no effect on any of the responses to the oils. The oils produced incomplete block of excitatory and inhibitory responses to octopamine even at high doses (10(-3) mol l(-1)), and they had similar effects on responses to dopamine and acetylcholine. The oils (10(-5)-2 x 10(-3) mol l(-1)) all increased the frequency of contractions of the isolated esophagus and progressively reduced their amplitude. The effects were similar to those of octopamine but were not blocked by phentolamine, metoclopramide, or prolonged exposure of the esophagus to octopamine. The results suggest a variety of actions that could contribute to toxic effects in molluscs, but there was no evidence for specific actions on octopamine receptors, either as agonists or antagonists. Evidence is presented that nonspecific depolarization produces their octopamine-like actions.     

循环水系统给回水温差减小原因探究

从凉水塔内填料、布水管、风机运行、水冷器运行等方面查找循环水系统给回水温差减小的原因,并提出了解决的方案.     

烧成系统旁路放风装置的过程研究与开发设计

为解决原燃料中钾、钠、氯、硫等元素对新型干法窑生产过程造成影响,使系统运行稳定,以保证产品质量.采用窑尾旁路放风装置是目前解决高含量钾、钠、氯问题的有效途径.采用CFD数值模拟技术,利用在开源代码OpenFOAM基础上的开发模型,通过对折流式放风装置的参数化研究,以及与直流式混合室的对比,对两种型式的放风装置进行综合分析.研究结果表明:(1)折流式放风装置,采用低入口风速有利于提高冷却效果;其出口面积的大小影响装置的阻力,据此可通过出口尺寸确定来调整系统平衡;但在出口处会有部分高温区域与器壁相接触,可能造成结皮堵塞.(2)细长型蜗壳折流式混合室的冷却风混合效果不如短蜗壳好. (3)直流式放风装置,在出口处克服了折流式的缺陷,但其进口处也会存在部分高温区域与器壁相接触现象,且其混合强度较弱,需较长的混合距离.     

急停系统在拉伸线生产中的应用

介绍了急停系统在拉伸线安全生产中的作用及原理,并对实际当中出现的问题进行了总结。急停系统直接切除了动力电源,同时在PLC程序中的报警,联锁功能是对其安全保护的补充。     

SHS of high-purity MAX compounds in the Ti-Al-C system

During the synthesis of MAX phases using combustion synthesis (or Self-Propagating High-temperature Synthesis), the main drawback is the presence of binary phases, and especially the simple MX carbide, when X = C. Our experiments were designed in order to check whether the cooling rate of the sample immediately after synthesis might play a key role for obtaining samples with low-level carbide contents. In the best conditions, a TiC content of about 2% only has been observed. A systematic study on the direct effect of the cooling rate on the final composition has then been conducted, and confirms that high cooling rates allow the synthesis of high-purity MAX phases in the Ti-Al-C system.      

HSE管理体系在石化装置的应用

本文对化工厂易发事故进行了分析,并将HSE管理体系应用于管理中,提出了应急预案模式,保证了安全生产。     

洗浴行业热水管道系统的清洗

根据洗浴中心的特点,制定出切实可行的工艺方案,在不影响洗浴中心生意的情况下,取得良好的清洗效果。     

氢气纳西姆机组在氢处理工序中的应用

介绍了氢气纳西姆机组在氢处理工序中的应用情况及其控制方案在生产中的实现和运行效果。     

国产聚酯装置PTA下料系统的优化

国产聚酯装置采用康柏斯PTA称量仪在使用中存在着下料量时大时小,稳定性差、浆料密度波动大等不足之处。通过分析异常现象并加以改进:在旋转下料阀上方增加一条氮气排气管、增加浆料密度校正模块、增加旋转下料阀支撑平台,使PTA下料系统得以优化。     

中性线在三相四线制供电系统中的作用

通过定量分析,论述了三相四线制供电系统中中性线的重要作用;强调指出,若要保证三相相电压在允许的电压范围内,必须使中性线连接完好,电压偏移在允许的范围内;并利用PSPICE仿真,说明了中性线阻抗变化对中性点电压偏移的影响,从而提出了保护措施。     

新疆天业滴灌系统的发展与创新

总结了新疆天业膜下滴灌系统10年发展历程中各阶段的特点,介绍了新疆天业研究开发出的新型滴灌系统,新疆天业新型滴灌系统过滤效率高、能量损耗小、安装简单、机耕作业便利、灌水及时,均匀度高,有利于与自动化控制系统相结合,平均亩增产6%左右、较原有系统亩综合效益增加百元以上,且系统性能高,推广应用前景广阔。     

芳烃装置水系统优化操作的研究

对吉林石化公司芳烃装置抽提单元水系统的参数进行了优化,通过控制水洗比、降低回收塔真空度、回流比等操作,节约了溶剂,降低了消耗。     

化工过程中真空系统的选型设计

阐述了化工过程中真空系统的选型设计与计算方法,并对真空泵选型设计提出一些建议。结合工程应用实例,验证了设计计算方法的可行性。