Study of polymer thermal and mechanical properties using a fiber Bragg grating thermal sensor

A simple and practical method for the study of polymer thermal and mechanical properties using a fiber Bragg grating (FBG) sensor is presented for the first time, in which the FBG is embedded in a typical epoxy polymer. By measuring the sensitivity change of the FBG sensor, changes of the thermal-mechanical properties of the polymer with temperature and pressure can be measured. The experimental results show that this technique is capable of providing continuous in-line monitoring such properties with high sensitivity during transformation between the glassy state and the rubbery state of a polymer within the temperature and pressure range of 20 to 180 C and 0 to 15 MPa. (c) 2007 Society of Photo-Optical Instrumentation Engineers.

Study of polymer thermal and mechanical properties using a fiber Bragg grating thermal sensor

A simple and practical method for the study of polymer thermal and mechanical properties using a fiber Bragg grating (FBG) sensor is presented for the first time, in which the FBG is embedded in a typical epoxy polymer. By measuring the sensitivity change of the FBG sensor, changes of the thermal-mechanical properties of the polymer with temperature and pressure can be measured. The experimental results show that this technique is capable of providing continuous in-line monitoring such properties with high sensitivity during transformation between the glassy state and the rubbery state of a polymer within the temperature and pressure range of 20 to 180 C and 0 to 15 MPa. (c) 2007 Society of Photo-Optical Instrumentation Engineers.

一种鸡胚胎心率记录的新方法

鸡胚胎是一种被广泛应用于发育生物学研究的实验材料。在以鸡胚胎为动物模型的各项研究工作 中, 心率常被看作是一个很重要的反应胚胎生理活动指标。本文详细介绍了一种侵入性的心电记录新方法, 在 正常的生理条件下通过记录鸡胚胎心电的变化来监测心率。首先在蛋壳上钻孔, 将电极插人蛋内, 然后通过放 大器放大, 板转换, 将心电信号输人电脑进行分析处理, 提取与心率相关的信息。这种记录方式对胚胎损 伤较小, 不影响胚胎的正常发育具有灵敏度高, 操作简单, 容易掌握等特点。

Intraperitoneal injection of extracted microcystins results in hypovolemia and hypotension in crucian carp (Carassius auratus)

Circulatory responses of crucian carp injected intraperitoneally with extracted micro-cystins (MCs) were studied at sublethal and lethal doses (150 and 600 mu g MC kg(-1) body mass, respectively). Mean arterial blood pressure (MAP), heart rate, hematocrit (Hct), red blood cell (RBC) counts, and circulating blood volume (BV) were assayed at 0, 1, 3, 12, 24, and 48 h post-toxin administration. MAP decreased significantly in a dose-dependent manner over time. Within the 48-h test period, the lethal dose as well as the sublethal dose resulted in a steady decline of MAP without recovery. Heart rate significantly increased within 24 h post-injection as blood pressure significantly dropped, then showed a terminal decline to the control level. The dose-dependent decreases in BV and Hct were directly related to the drop in MAP. Intraperitoneal injection of a lethal dose of MCs led to hepatic and gill hemorrhage. Consequently, crucian carp given MCs suffered from hypovolemic hypotensive shock. (C) 2009 Elsevier Ltd. All rights reserved.

The profound effects of microcystin on cardiac antioxidant enzymes, mitochondrial function and cardiac toxicity in rat

Deaths from microcystin toxication have widely been attributed to hypovolemic shock due to hepatic interstitial hemorrhage, while some recent studies suggest that cardiogenic complication is also involved. So far, information on cardiotoxic effects of MC has been rare and the underlying mechanism is still puzzling. The present study examined toxic effects of microcystins on heart muscle of rats intravenously injected with extracted MC at two doses, 0.16LD(50) (14 mu g MC-LReq kg(-1) body weight) and 1LD(50) (87 mu g MC-LReq kg(-1) body weight). In the dead rats, both TTC staining and maximum elevations of troponin I levels confirmed myocardial infarction after MC exposure, besides a serious interstitial hemorrhage in liver. In the 1LD(50) dose group, the coincident falls in heart rate and blood pressure were related to mitochondria dysfunction in heart, while increases in creatine kinase and troponin I levels indicated cardiac cell injury. The corresponding pathological alterations were mainly characterized as loss of adherence between cardiac myocytes and swollen or ruptured mitochondria at the ultrastructural level. MC administration at a dose of 1LD(50) not only enhanced activities and up-regulated mRNA transcription levels of antioxidant enzymes, but also increased GSH content. At both doses, level of lipid peroxides increased obviously, suggesting serious oxidative stress in mitochondria. Simultaneously. complex I and III were significantly inhibited, indicating blocks in electron flow along the mitochondrial respiratory chain in heart. In conclusion, the findings of this study implicate a role for MC-induced cardiotoxicity as a potential factor that should be considered when evaluating the mechanisms of death associated with microcystin intoxication in Brazil. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

网络成瘾者心率变异性频谱特征及人格相关因素的研究

The aim of this research is to explore heart rate variability frequency field characteristics and personality influential factors of internet addicts by experimentation and questionnaire. Two studies were carried out: study 1 was to explore the pathological and mental mechanism of internet addicts by heart rate variability physiological index and EPQ and internet addiction scale. Study 2 was to compare the personality and mental characteristics between internet addicts and Non-addicts. The testees were 30 internet addict schoolboys who were in-patient and 43 schoolboys who accorded with qualification from grade 2 in senior high school and sophomore. It is found that: 1、 Internet addicts have obviously lower HFNU than Non-addicts， but have obviously higher LFNU and LF/HF ratio than Non-addicts. Internet addicts have dysfunction in their sympathetic and parasympathetic system; 2、 Internet addicts and Non-addicts have no significant difference in their EPQ except their lying point, but the nervous characteristics of EPQ of internet addicts have influence on their equipoise of parasympathetic system, that is to say when the score of nervous characteristics of EPQ become higher, equipoise of parasympathetic system become worse and worse. However the EPQ personality characteristics of non-addicts have no influence on their sympathetic and parasympathetic system. 3、 The extent of internet addiction of the internet addicts is independent of their equipoise of parasympathetic system, but non-addicts use internet more time, their equipoise of parasympathetic system become lower, there is the significant difference in the neurophysiology between internet addicts and non-addicts. That is to say internet environment is safe to most adolescent, they can make use of internet environment accurately, but internet addicts, their physiological and psychological level has changed to a certain, need to be treated.； 4、 Serious internet game addicts have the metal characteristics of low social support, low purpose in life and low adventure; 5、 The objective support、support utilization of social support questionnaire and sensation seeking characteristics have prognosticative function for internet addiction degree; 6、 Serious internet game addicts have the metal characteristics of low social support, low lying particularity, they are inclined to self abandonment. Serious internet game addicts of low N characteristic have high sensation seeking characteristic, and at the same E personality foundation, they also seek new stimulus with higher intension. There is a prompt that we should pay attention to internet addicts’ personality so that obtain better curative effect for internet addiction therapy.

不同干扰条件下社会认知偏离者两半球协同功能研究

Previous studies have witnessed some psychological or behavioral deviation (such as aggressive behavior) might have an association with cerebral hemisphere cooperative dysfunction, however, it is still unclear whether there is an association between individuals with social cognitive bias and their hemispheric cooperative functions especially while the interhemisphere cooperative processing is under the conditions of emotional interferences. The purpose of this study is to explore the differences between the social cognitive bias group and the normal group’s interhemispheric cooperative functional activity under the conditions of with or without interferences. Methods: According to Dodge’s (1993) model of “social-cognitive mechanisms in the development of conduct disorder and depression”, a 51 items of “social cognitive bias scale” was created and was used to screen the high score group. 20 male subjects was composed of high score group and other 23 matched the control group. Stimulus tachistoscopically presented to the bilateral visual field and compared with the central. Both group’s interhemispheric cooperative functional activity were observed and compared under the conditions of without interference- i.e. base level and with the emotional interferences of white noise level and negative evaluative feedback speech level while finishing: experiment one: Chinese word-figure Stroop analogue task; experiment two: two single Chinese Characters combination task. Heart rate and respiratory rate were simultaneously recorded as index of emotional changes. Results: ① The high score group showed a decrease in processing accuracy compared with the normal group under the condition of white noise interference level in experiment one. ② Still under the condition of white noise interference level, there were more reaction time and more errors were observed in high score group than normal in experiment two. ③ Both groups showed speed up effect and the strategic processing tendency of speed-accuracy trade-off effect under the condition of white noise interference level in both experiments. ④ Between group differences of interhemipheric cooperative function were not observed under the conditions of base level and the negative evaluative feedback speech level within both experiments. Conclusion: The results suggested that interhemispheric cooperative functional differences exists between the two groups, characterized as ① differences existed in interhemispheric cooperative processing strategy between the two groups, with the high score group presented “hierarchic” deficiency strategy. ② the appearance of the differences between the two groups were condition specified , and in this research it was only under the white noise interference condition. ③ the features of the differences between the two groups were the differences on multidimensional performances and with a deficit orientation in high score group. ④ the varieties of the differences were changing with cooperative tasks, as in this research the high score group performed worse in complementary cooperative task. In addition, both group adjusted the processing strategy respectively under the condition of white noise evoked emotional interference implied that the interaction between the interhemisphere cooperative processing and emotion might exist.