Conditional and indirect effects of age of first exposure on PTSD symptoms

Childhood violence exposure (CVE) in formative developmental years may have potent effects on severity and complexity of post-traumatic stress symptoms (PTSS) in adulthood, yet little research has examined the role of age of first exposure in the context of polyvictimization or gone beyond an examination of direct effects. The current study examines the specific associations between age of first exposure, total CVE, and posttraumatic stress symptoms in adulthood. Further, the conditional and indirect effects of age of first exposure on posttraumatic stress symptoms were examined. We hypothesized that age of first exposure to violence would be associated with higher total violence exposure across childhood, thereby predicting current posttraumatic stress symptom severity (i.e., indirect effect). We also postulated that age of first exposure would affect the relationship between total violence exposure and posttraumatic stress symptoms such that earlier exposure would exacerbate the effects of violence exposure (i.e., conditional effect). Participants included 269 violence-exposed adults recruited through MTurk; the mean age of first CVE was 6 years (SD = 3.29). Conditional process models indicated that age of first exposure was significantly associated with higher total childhood violence exposure, which in turn, was significantly associated with current posttraumatic stress symptoms in all domains. Further, a conditional effect of age of first exposure was present such that the relationship between total exposure to violence and symptoms of hyperarousal was stronger for those first exposed at earlier ages. Findings provide support suggesting the particular potency of early trauma on regulatory response systems.     

新兴煤矿地质构造体系分析

能过简单的力学分析,总结新兴煤矿断层发展、发育规律。     

Oxidative stress and disturbance in antioxidant balance in beta thalassemia major

Repeated blood transfusion in beta thalassemia major patients may lead to peroxidative tissue injury by secondary iron overload. In the present study, 72 children with beta thalassemia major were included. Serum levels of total lipid peroxides, Iron, Total Iron Binding Capacity, Copper, Zinc, Vitamin E, plasma Total Antioxidant Capacity, activity of Erythrocyte Superoxide Dismutase, were measured. The findings were compared with 72 age matched healthy controls irrespective of sex. A significant increase in the levels of lipid peroxide and Iron (p<0.001), whereas, significant decrease in the levels of vitamin-E, Total Antioxidant Capacity and Total Iron Binding Capacity (p<0.001) was observed. Serum Zinc was significantly increased (p<0.001) with significant decrease in the levels of copper (p<0.001). Non Significant increase in the activity of Erythrocyte Superoxide Dismutase (p>0.05) was found in the patients when compared with controls. This suggest that oxidative stress and reduced antioxidant defense mechanism play an important role in pathogenesis of beta thalassemia major.     

Serum copper in Alzheimer’s disease and vascular dementia

Alzheimer’s disease is the most common form of dementia in the elderly and it’s prevalence is rapidly rising. Oxidative stress plays important role in the pathophysiology of Alzheimer’s disease. Metals like copper, iron derived through diet can act as pro-oxidant under oxidative stress. In the present study, serum copper levels were evaluated in 50 patients with Alzheimer’s disease, 24 patients with Vascular Dementia and 30 controls. All the groups were also investigated for serum ceruloplsmin levels. The mean copper levels in Alzheimer’s disease and Vascular Dementia were significantly raised compared to controls. An attempt has been made to study the relationship of serum copper with ceruloplasmin. Our study found weak correlation between copper and ceruloplasmin levels in Alzheimer’s disease and Vascular Dementia.     

Plasma MDA and antioxidant vitamins in diabetic retinopathy

Hyperglycemia and dyslipidemia in diabetes mellitus induce increased lipid peroxidation and peroxyl radical formation, an important mechanism in genesis of microangiopathy. We took up a study on oxidative stress, measured by plasma MDA and antioxidant vitamin status in type − 2 DM patients with and without retinopathy and compared them with a control non-diabetic group. Lipid peroxidation marker MDA was significantly elevated (p < 0.001) in both the diabetic groups whereas, serum vitamin E and vitamin C registered a significant fall (p<0.001) as compared to controls. Our correlation study revealed a significant positive association between plasma MDA with both fasting and 2hr post prandial plasma glucose (r=0.81, p < 0.001, r=0.92, p <0.001) suggesting the role of hyperglycemia in free radical production. Plasma MDA also depicted significant positive relation (p< 0.001) with all lipid parameters except serum HDLc pointing the role of dyslipidemia towards lipid peroxidation. Plasma MDA level was also found to be negatively correlated with both the vitamins (p<0.001, p<0.001) in the study group explaining their protective consumption in the oxidative process prevailing in diabetic retinopathy.     

Oxidative stress and antioxidant status in normolipidemic AMI patients

The objective of the study was to observe the correlation between oxidative stress and antioxidants in myocardial infarct patients with normal lipid profile. In the present study investigation of lipid peroxidation and antioxidants were done in patients. This study was carried out on 165 AMI patients, (123 males and 42 females). The control group consisted on 165 normal healthy age-sex matched subjects (123 males and 42 females). Levels of Superoxide dismutase, Glutathione Peroxidase, Catalase, Malondialdehyde and Conjugated dienes were measured. The study found Superoxide dismutase, Glutathione Peroxidase, Catalase were significantly lower in activities (p<0.001) in AMI patients compared to controls. The markers of lipid peroxidation namely Malondialdehyde and Conjugated dienes were higher in AMI patients as compared to controls (p<0.001). The present study is clearly suggestive of increased oxidative stress in AMI patients. Oxidative stress appears as an etiological factor for myocardial infraction as a consequence the free radical scavengers levels are lowered in AMI patient.     

体育运动中青少年的控制信念和压力应对

大量研究表明主观控制与以问题为中心的应对策略相关,但主观控制与以情绪为中心的应对策略的关系则不是很明确。本研究以344名青少年运动参与者为被试（113名男性,231名女性）,通过让他们回忆经历过的压力情境,分别测量了压力、应对策略和控制信念。分层回归分析显示：对两种性别的人而言,主观压力能解释以情绪为中心的应对策略的较大部分的变异。总的来说,研究结果在很大程度上支持Compas的模型,即以问题为中心的应对策略与个体对压力情境的主观控制相关,而以情绪为中心的应对策略则与体验到的总体压力水平有更为密切的关系。在关于控制信念与应对策略的模型里,主观压力是一个需要考虑的重要变量。但是,它的重要性似乎取决于控制信念的维度。     

大学生热环境下中等强度运动的热调节反应和生理变化

为探讨大学生热环境下运动的热调节能力和生理变化情况。将18名男性大学生自愿者随机分为热环境运动组(HE组)和室温对照组(NE组),以55%VO2max强度分别在38±1℃和26±1℃环境下(相对湿度皆为73%±3%)进行60min功率自行车运动。每15min测定两组HR、RPE值和直肠温度,统计热环境下HR和RPE的相关关系;测定两组运动前后的体重变化、总出汗率、总出汗量、血尿素和疲劳指数。结果得出:两组被试运动15min HR、RPE组间差异不显著,但30min后HE组HR、RPE值显高于NE组并持续到运动结束;热环境下HR与RPE呈高度相关(r=0.839,P<0.01);运动过程中,NE组Tre低于HE组,运动30min后差异愈发明显;运动前后NE组体重丢失、总出汗量、总出汗率均低于HE组(P<0.05),BUN和FI明显低于HE组(P<0.01)。结论为:热环境下运动对HR、RPE、Tre的刺激更为深刻,并且体重丢失、脱水更为严重,更易导致肌体疲劳。