ABS汽车制动胎印的模拟与实现

汽车防抱死制动系统(ABS)的性能好坏有差异,制动时会在道路上留下不同的胎印。文中通过分析ABS汽车制动性能,建立了ABS汽车制动距离、滑移率与时间的关系,进而通过设置滑移率与制动胎印颜色深浅的关系模拟绘制出制动胎印,用于评价ABS汽车的制动性能及进行交通事故分析。

轮胎拖印分析道路交通事故车速的模型

道路交通事故发生前的车速(简称事故车速)是确定事故责任的依据,是研究事故再现的主要内容之一,也是目前国内外交通安全研究领域的一项重要课题。从事故现场的轮胎拖印出发,分析建立了根据轮胎拖印计算事故车速的模型。考虑到事故现场汽车各轮胎拖印的多样性和交警在事故现场采集数据快速准确的要求,运用能量守恒定律,将轮胎现场印迹分为胎印、擦印和拖印三阶段,将现场轮胎拖印测量起始点确定为轮胎胎印的起始点,并引入前后轴荷比和制动拖印修正系数。建立的事故车速分析计算模型综合考虑了事故车辆装载质量的变化、各车轮轮胎拖印长度的不等、制动过程轮胎与路面附着系数的变化等因素。

Expression and location of α-fetoprotein during rat colon development

AIM： To investigate the expression of α-fetoprotein （AFP）, a cancer-associated fetal glycoprotein, and its involvement during rat colon development. METHODS： Colons from Sprague-Dawley rat fetuses, young and adult （8 wk old） animals were used in this study. Expression levels of AFP in colons of different development stage were detected by reversetranscriptase PCR （RT-PCR） and Western blotting. To identify the cell location of AFP in the developing rat colons, double-immunofluorescent staining was performed using antibodies to specific cell markers and AFP, respectively. RESULTS： The highest levels of AFP mRNA were detected in colons of rats at embryonic day 18.5 （e18.5）. Compared to e18.5 d, the AFP expression was significantly decreased during rat development （85% for e20.5, P 〈 0.05, 58% for postnatal day 0.5 （P〈0.5）, P 〈 0.05, 37% for P7, P 〈 0.05, 24% for P14, P 〈 0.05, and 11% for P21, P 〈 0.05） and undetected in adult rats. Only the 72-kDa isoform of AFP was detected by Western blotting, the expression pattern was similar to AFP mRNA and conformed to the results of mRNA expression. The AFP positive staining was identical to different distribution patterns in fetuses, young and adult animals and positive staining for both AFP and vimentin was overlapped in mesenchymal cells at each stage tested. CONCLUSION： This study has for the first time demonstrated that AFP is localized in the mesenchyme of rat colon from the embryo to the weaning stage by immunofluorescence and presents 72-kDa isoform in the developing rat colons by Western blotting. The dynamic expression of AFP in the various developmental stages of the colon indicates that AFP might be involved in many aspects of colon development.

Surface Modification of Pyrolytic Carbon Black from Waste Tires and Its Use as Pigment for Offset Printing Ink

Pyrolysis has the potential of transforming waste into valuable products. Pyrolytic carbon black (PCB) is one of the most important products resulting from the pyrolysis of used tires. One of the most significant applica-tions of modified pyrolytic carbon black is its use as pigment for offset printing ink to obtain high added values. Inverse gas chromatography (IGC) results show that a large quantity of inorganic matters and carbonaceous deposit are removed by treating the pyrolytic carbon black with nitric acid solution. Plenty of active sites originally occu-pied by inorganic ash and coke are recovered. The surface energy of pyrolytic carbon black (TWPC)modified by titanate-coupling agent-especially the specific interaction γ sspdetermined by the specific probe molecule, tolu-ene-shows the strong interaction between the TWPC and the synthetic resins. The offset printing ink performance confirms the IGC prediction. And TWPC has the great potential of applications in printing ink industry as pigment.

滚动轴承内沟、外沟超精研机的工装改造

套圈精研工序是轴承套圈加工的最后一道工序,也是最关键的一道工序,因此通过改造加工工件工装支点、支点座、定心轴、不合理处解决影响外观质量的套圈划伤划痕磕碰伤及胎垫印等。

Glucose Metabolic and Gluconeogenic Pathways Disturbance in the Intrauterine Growth Restricted Adult Male Rats

Objective To explore the molecular mechanism of type 2 diabetes in intrauterine growth restricted adult rats through determination of blood glucose and expression of gluconeogenic enzymes in liver.Methods Male intrauterine growth restriction(IUGR) offspring induced by maternal protein-malnutrition and normal controls were studied.The body weights of offspring rats were weighted from birth to 12 weeks of age.Fasting plasma glucose and insulin levels were determined by glucose oxidase method and enzyme-linked immunosorbent assay(ELISA) respectively at 1 week,8 weeks,and 12 weeks.Peroxisome proliferator-activated receptor-γ coactivator-1α(PGC-1α),phosphoenolpyruvate carboxykinase(PEPCK),and glucose-6-phosphatase(G6Pase) mRNA and protein levels in liver were measured by real time RT-PCR and Western blot in newborn rats(Week 1) and adult rats(Week 12).Results Birth weights of IUGR rats were significantly lower than those of controls until 4 weeks later,when IUGR rats caught up to controls.Between 8 and 12 weeks,the growth of IUGR rats surpassed that of controls.No significant differences were observed in blood glucose and insulin levels at newborn rats between the two groups.However,by the end of 8 weeks IUGR rats developed hyperinsulinemia and high insulin resistance index.At the age of 12 weeks,IUGR rats had mild fasting hyperglycemia.In addition,hepatic PGC-1α mRNA and protein levels as well as hepatic mRNA levels of PEPCK and G6Pase at Week 1 and Week 12 in IUGR rats were all significantly higher than those of controls(P<0.05).Conclusions As a result of intrauterine malnutrition,the expression of gluconeogenic genes is exaggerated in offspring.This change stays through adulthood and may contribute to the pathogenesis of type 2 diabetes.

Canine Distemper Virus Utilizes Different Receptors to Infect Chicken Embryo Fibroblasts and Vero cells

Inducing animal viruses to adapt to chicken embryos or chicken embryo fibroblasts(CEF) is a common method to develop attenuated live vaccines with full security.Canine distemper virus(CDV) also does this,but the mechanisms and particular receptors remain unclear.Virus overlay protein blot assays were carried out on CEF membrane proteins,which were extracted respectively with a Mem-PER TM kit,a radioimmunoprecipitation assay buffer or a modified co-immunoprecipitation method,and revealed a common 57 kDa positive band that differed from the 42-kDa positive band in Vero cells and also from those receptors reported in lymphocytes and 293 cells,indicating a receptor diversity of CDV and the possibility of the 57-kDa protein acting as a receptor that is involved in adaptive infection of CDV Kunming strain to CEF.

Colon Duplication Combined with Mature Teratoma-A Case Report

Gastrointestinal duplication is an uncommon congenital abnormality, and colonic duplication combined with teratoma has rarely been reported. A 24-year-old man presented to the Emergency Department with a sudden onset of severe abdominal pain lasting 2 hours without intermission, and also complained to have who had chronic constipation since his birth.Multislice CT imaging showed 2 masses in the retroperitoneal space. The one huge cystic mass was detected behind the transverse colon, pancrease and stomach without infiltration into the surrounding tissues. The right mass containing soft tissues and bones pushed aside the inferior vena cava and right kidney.The cystic duplication and the right mass were excised separately.This case indicates that a patient diagnosed as colonic duplication should receive further differential diagnosis to identify if it coexists other diseases, espedally the teratoma.