INVESTIGATION IN REDUCING EXHAUST EMISSIONS FROM TWO STROKE MOTORCYCLES

Test results of reducing two stroke motorcycle emissions with new type carburettors and electronic fuel injection systems are presented. Analyses and comparison between different systems are discussed. The adoption of electronically controlled injection and corresponding electronic control technique is an effective measure of prolonged vitality to improve emissions from two stroke motorcycles. Suggestions about the strategic steps of China′s motorcycle emission control are proposed.

CircR-ZC3HC1 mediates MiR-384-5p/SIRT1 axis to promote neuronal autophagy and relieves ischemic stroke

Objective:Circular RNAs(circRNAs)have been shown to involve in pathological processes of ischemic stroke(IS),including autophagy.This study was designed to explore the effect of circR-ZC3HC1 on neuronal autophagy in IS and the related mechanisms.Methods:Expression of circR-ZC3HC1 in blood samples of IS patients and healthy controls was detected.Hippocampal neurons were treated with oxygen and glucose deprivation(OGD)to establish IS in vitro model.The expression of LC3 and p62 and the number of autophagosomes were examined to evaluate the autophagy level of OGD induced neurons using western blotting and transmission electron microscope.Cell apoptosis rate and the expression of cleaved caspase-3,Bax,and Bcl-2 were assessed byflow cytometry and western blotting.The binding relationships among circR-ZC3HC1,miR-384-5p,and SIRT1 were predicted and verified.Results:Low expression of circR-ZC3HC1 was found in blood samples of IS patients and OGD-treated neurons.Overexpressed circR-ZC3HC1 or inhibited miR-384-5p expression promoted autophagy and inhibited apoptosis of OGD-treated neurons,which could be reversed by further 3-MA treatment.Mechanistically,circR-ZC3HC1 targeted miR-384-5p to mediate SIRT1 expression.miR-384-5p overexpression or SIRT1 knockdown in the presence of circR-ZC3HC1 overexpression in OGD-treated neurons lead to reduced autophagy and enhanced apoptosis.Conclusion:Collectively,circR-ZC3HC1 promoted neuronal autophagy to attenuate IS via miR-384-5p/SIRT1 axis.

The -250G>A polymorphism in the hepatic lipase gene promoter influences plasma lipid profile and lipoprotein ratio in patients with ischemic stroke

Objective:To evaluate the influence of–250G>A(rs2070895)polymorphism in hepatic lipase gene(LIPC)promoter on plasma lipid parameters of ischemic stroke patients.Methods:A total of 100 stroke patients and 100 control subjects matched for sex(59 men and 41 women)and age were selected.Hepatic lipase activity and lipid profiles were measured while lipoprotein ratios were calculated.Genotyping of the–250G>A promoter polymorphism of the LIPC was performed by the polymerase chain reaction and restriction fragment length polymorphism method combined with 2%gel electrophoresis and then confirmed by direct sequencing.The LIPC promoter gene sequencing data were compared with refseqNG011465.1 LIPC from GenBank.Results:The frequencies of GG,GA and AA genotypes of LIPC rs2070895 polymorphism were 39%,45%and 16%for the control,10%,37%and 53%for the stroke subjects(P<0.0001),respectively.The frequencies of G and A alleles were 61.5%and 38.5%for the control,and 28.5%and 71.5%for the stroke subjects(P<0.0001).Our study shows that the mutant allele of the LIPC promoter was associated with dyslipidemia,lower hepatic lipase activity,and this variation contributed to the increased defective plasma high-density lipoprotein-cholesterol(HDL-C),HDL2-C and HDL3-C concentration for both subjects.The control subjects had 6 single nucleotide polymorphism and 6 amino acid substitutions while the stroke subjects had 32 single nucleotide polymorphism and 20 amino acid substitutions.Conclusions:LIPC–250G>A polymorphism can influence plasma lipid profiles and lipoprotein ratios in patients with ischemic stroke.

基于stroke分级的道路网匹配研究

路网匹配一直是路网数据更新和变化发现的关键技术。针对用"弧段—结点"模型表达的路网数据,设计了stroke生成方法,对路网进行了stroke生成,并根据stroke长度进行了等级划分。在等级划分的基础上,提出了基于stroke分级的路网匹配算法。通过仿真验证,该匹配算法对研究数据进行stroke匹配的正确率达到91.4%,能得到较好的匹配效果。

microRNA-455-5p alleviates neuroinflammation in cerebral ischemia/reperfusion injury

Neuroinflammation is a major pathophysiological factor that results in the development of brain injury after cerebral ischemia/reperfusion.Downregulation of microRNA(miR)-455-5p after ischemic stroke has been considered a potential biomarker and therapeutic target for neuronal injury after ischemia.However,the role of miR-455-5p in the post-ischemia/reperfusion inflammatory response and the underlying mechanism have not been evaluated.In this study,mouse models of cerebral ischemia/reperfusion injury were established by transient occlusion of the middle cerebral artery for 1 hour followed by reperfusion.Agomir-455-5p,antagomir-455-5p,and their negative controls were injected intracerebroventricularly 2 hours before or 0 and 1 hour after middle cerebral artery occlusion(MCAO).The results showed that cerebral ischemia/reperfusion decreased miR-455-5p expression in the brain tissue and the peripheral blood.Agomir-455-5p pretreatment increased miR-455-5p expression in the brain tissue,reduced the cerebral infarct volume,and improved neurological function.Furthermore,primary cultured microglia were exposed to oxygen-glucose deprivation for 3 hours followed by 21 hours of reoxygenation to mimic cerebral ischemia/reperfusion.miR-455-5p reduced C-C chemokine receptor type 5 mRNA and protein levels,inhibited microglia activation,and reduced the production of the inflammatory factors tumor necrosis factor-αand interleukin-1β.These results suggest that miR-455-5p is a potential biomarker and therapeutic target for the treatment of cerebral ischemia/reperfusion injury and that it alleviates cerebral ischemia/reperfusion injury by inhibiting C-C chemokine receptor type 5 expression and reducing the neuroinflammatory response.

Association of ALOX5AP with ischemic stroke in eastern Chinese

BACKGROUND：5-1ipoxygenase protein （ALOX5AP） has been recognized as a susceptibility gene for stroke and coronary artery diseases. The present study was to explore the role of this gene in the eastern Chinese patients with ischemic stroke.METHODS： Using a case-control design, we studied 658 patients with ischemic stroke and 704 unrelated population-based controls who were age- and sex-matched. The 658 patients were classified by the Trial of Org 10172 in Acute Stroke Treatment （TOAST）. Two single-nucleotide polymorphisms （SNPs） covering ALOX5AP were genotyped. RESULTS： The genotype frequencies of TG of the SNPs rs17222919 located in the promoter of the ALOX5AP gene were significantly higher in patients with ischemic stroke than in controls （OR＊=1.34, 95%C1＊=1.02-1.75）, especially in patients with ischemic stroke caused by small-artery occlusion （SAO） （OR＊=1.40, 95%C1＊=1.02-1.93）. Meanwhile, the genotype frequencies of TG and TG/ GG were higher in female patients than in the controls. After specification, the genotype frequencies of TG and TG/GG were higher in the patients than in controls with hypertension. The genotype frequencies of AG and AG/GG of the SNPs rs9579646 located in the intron of the ALOX5AP gene were higher in the controls than in the patients. After specification, the genotype frequencies of TG were higher in the controls than patients without hypertension. CONCLUSIONS： The present study suggests that sequence variants in the ALOX5AP gene are significantly associated with ischemic stroke.

Silencing miRNA-324-3p protects against cerebral ischemic injury via regulation of the GATA2/A1R axis

Previous studies have suggested that miR-324-3p is related to the pathophysiology of cerebral ischemia,but the mechanism underlying this relationship is unclea r.In this study,we found that miR-324-3p expression was decreased in patients with acute ischemic stroke and in in vitro and in vivo models of ischemic stro ke.miR-324-3p agomir potentiated ischemic brain damage in rats subjected to middle cerebral artery occlusion,as indicated by increased infarct volumes and cell apoptosis rates and greater neurological deficits.In a PC12 cell oxygen-glucose deprivation/reoxygenation model,a miR-324-3 p mimic decreased cell viability and expression of the anti-apoptotic protein BCL2 and increased expression of the pro-apoptotic protein BAX and rates of cell apoptosis,whereas treatment with a miR-324-3p inhibitor had the opposite effects.Silencing miR-324-3p increased adenosine A1 receptor(A1R)expression thro ugh regulation of GATA binding protein 2(GATA2).These findings suggest that silencing miR-324-3p reduces ischemic brain damage via the GATA2/A1R axis.

SJ 10W-30四冲程摩托车油的开发及使用

随着我国环保法规的日益严格,四冲程摩托车数量越来越多,开发专门的四冲程摩托车油非常必要。文章介绍了四冲程摩托车油不同于普通汽油机油的性能特点,即同时满足离合器、齿轮、曲轴箱的润滑要求。介绍了JASO T903-2006的规格标准。SJ 10W-30四冲程摩托车油的研制过程,利用大庆加氢异构化基础油和RHY3061A复合剂调制的四冲程摩托车油,通过了API SJ的发动机台架试验,满足SJ级的规格要求,通过JSAO T904试验证明研制油为MA油。10000 km的使用试验证明研制油的清净性、抗氧化性能、抗磨损性能和参比油相当,满足WY-125C型摩托车的润滑要求,并且研制油的排放性能优于参比油,有利于环境保护。

降低二冲程摩托车废气排放的技术措施

介绍了国内外近年来在降低二冲程摩托车废气排放方面所采取的主要技术措施 ,分析比较了各种措施在结构、净化效果和成本等方面的特点 ,指出 :对现有二冲程摩托车化油器进行调整使混合气变稀、并改进化油器进气道形状 ,是降低二冲程摩托车废气排放的最简单且有效的措施 ;采用缸内燃料直接喷射技术是唯一能很好解决二冲程摩托车废气排放的技术措施 ;与采用缸内燃料直接喷射技术相比 ,分层扫气的结构简单、成本低 ,净化效果比化油器混合气稀化好 。

降低摩托车发动机排气排放的试验研究

在ＱＭ５０ＱＷ型摩托车用二冲程发动机上，通过在化油器后加装进气旋流器、活塞裙部打排气回流孔、消声器中装催化转化器以及排气口和扫气通道引入空气等措施的采用，使发动机排气排放和燃油经济性得到不同程度地改善。另外，还对不同怠速转速、不同怠速空气螺钉位置及不同气缸盖温度对排气排放的影响进行了探讨。

一种基于MC68HC08的摩托车电喷控制系统

根据摩托车发动机的工作原理,作者设计并调试完成了一个基于MC68HC08单片机的电喷控制系统,并应用该系统在台架上进行了单杠四冲程发动机CG125的匹配实验,较好地解决了发动机动力性、经济性及排放之间的矛盾.经实验测量表明,该电喷控制系统可以使摩托车发动机的功率提高10%左右,燃油消耗率降低15%左右,废气排放量减少20%左右.

城市中摩托车的大气污染及控制技术

论述了城市中，特别是在中国，摩托车对大气污染的严重性及其有害排放的特殊性；国际上排放法规的进步与中国的差距。在降低摩托车，主要是二冲程摩托车对大气污染的技术措施中，着重论述低烟二冲程油的试验研究。结果表明，采用低烟二冲程油是降低摩托车排烟污染的关键措施。

125mL摩托车发动机噪声分析

通过对某 1 2 5mL摩托车用四冲程发动机的近场噪声测量和频率跟踪分析 ,得到了发动机各部位的近场噪声频谱特性 ,因而可以识别和分离发动机噪声源 ,并提出应注意的问题和改进方向。

排气动力效应在二冲程摩托车上的应用

排气动力效应对于二冲程摩托车的性能有很大影响,特别体现在排气净化消声器的结构设计中,设计得合理,将会在保证排放控制的前提下,动力性和经济性比原车都有所改善,已经通过模拟计算及实践获得了证明。

我国摩托车排烟状况及其对策

以即将制定的《摩托车和轻便摩托车排气可见污染物限值及测量方法》标准中的限值为依据,用急加速法对我国新生产摩托车和在用摩托车的排烟进行部分抽样检测,结果表明,四冲程摩托车的排烟通过率为100%。对二冲程摩托车而言,采用自带润滑油以及自行润滑模式,无论是新生产摩托车还是在用摩托车其排烟通过率均在10%以下。若采用低烟油且混合比为50∶1时,则通过率可达60%以上。

摩托车发动机用油的发展趋势

分析了中国摩托车工业的发展趋势,介绍了四冲程摩托车发动机油的特点和规格。"长城"牌四冲程摩托车发动机油已获得JASO质量认证,能够满足四冲程摩托车发动机的特殊性能要求。

降低二冲程摩托车尾气排污的试验研究

通过在QM50QW和QS90二冲程摩托车上加装进气旋流器、催化器以及采取扫气道、排气口引入二次空气和活塞裙部钻排气回流孔等措施 。

液压盘式制动器制动泵性能仿真与试验台架检测

为检测摩托车制动泵性能,以液压盘式制动器制动泵活塞无效行程为研究对象,分析了节流口质量流量特性方程和有限容积气容的绝热放气能量方程,基于Matlab/Simulink搭建了气缸排气运动过程仿真模型,并结合VC++设计的摩托车制动泵性能检测系统,利用"压力突变点"计算活塞无效行程。对比分析了试验台架测试数据与仿真结果,结果表明,测试结果与仿真结果基本一致,测试数据准确,检测系统各部分性能稳定,在摩托车配件厂有较高的应用价值。

二、四冲程摩托车纵横谈(1)

二冲程摩托车发动机体积功率高,体积小,质量小且结构简单,但存在着油耗较高、污染严重的固有弊端;四冲程摩托车发动机油耗低、排污少,工作可靠,但配气机构复杂,配合精度要求高,所以造价昂贵,维修也不方便。因此二、四冲程摩托车用发动机各有利弊,应扬长避短,不断发展。

降低二冲程摩托车排气污染的研究

本文针对我国二冲程摩托车排气污染的现状, 简要分析了常见的控制排气污染的措施以及二冲程摩托车催化转化器的结构和工作原理。对二冲程摩托车催化转化器及二次空气供给阀的安装位置进行了试验研究,而且通过试验分析了催化转化器转化率的影响因素。试验表明:安装催化转化器和二次空气供给阀后的二冲程摩托车的排放有了明显的下降。