The effects of stress on dna repair capacity

Abstract

Research has shown that lymphocytes of high-distress patients have reduced DNA repair relative to that of low-distress patients and healthy controls. Furthermore, deficits in repair are associated with an increased risk of cancer. Using and academic stress model, we hypothesized that students would exhibit lower levels of Nucleotide Excision Repair (NER) during a stressful exam period when compared to a lower stress period. Participants were 19 healthy graduate level students. NER was measured in lymphocytes using the unscheduled DNA synthesis (UDS) assay with slide autoradiography. Contrary to prediction, mean values for NER significantly increased during the higher stress period relative to the lower stress period controlling for background differences in repair. Furthermore, lymphocytes had significantly increased repair of endogenous damage during the higher stress period. Stress appears to directly increase DNA repair. Additionally, stress may increase DNA repair indirectly by increasing damage to DNA.     

Toward an understanding of aging in plutonium from direct measurements of stored energy

ABSTRACT

We present here the first direct measurement of the radiation-damage-induced energy stored in δ-phase plutonium. The primary mode of radioactive decay of ²³⁹Pu occurs with a time constant of τ=1.1?×?10¹²?s. Each decay imparts about 85?keV of recoil energy to the uranium byproduct, 5.2?Mev to the alpha particle, and a spectrum of mostly low energy gamma rays with the most probable at 51?keV [1]. Most of the decay energy is converted immediately to heat, releasing about 1.9?mW/g. However, some thermally-recoverable energy remains trapped. Reported here are measurements of that stored energy using differential scanning calorimetry (DSC) applied to ²³⁹Pu-2.0 at.%Ga δ-phase alloy. Retained energy of ～2 J/g saturates at about 5 months and is unchanged after 30 years. The magnitude of the stored energy agrees with a short-bond defect model that that we present here. This model treats radiation damage as a Pu impurity with shortened bond lengths. It explains the change in known properties with age and predicts that density increases with age, contrary to current thinking. The short-bond impurities proposed are expected to act like other impurities, affecting strength, phase transitions, grain boundaries and other metallurgical properties.     

骨髓捐献人中途拒捐的民事责任探析——基于信赖保护的视角

基于捐献行为的公益性、单务性和人身性,各国法律赋予捐献人任意撤销权,但是出于对捐献人允诺的信赖而改变自身处境的接受人利益也应该得到保护.从信赖保护的视角出发,在血型高分辨检测之前,捐献人一旦签订了捐献协议,即负有保护接受人信赖利益的义务,捐献人虽然有权中途拒捐,但应当承担信赖赔偿责任.     

Does exercise-induced muscle damage impair subsequent motor skill learning?

Motor skill learning is a fundamental aspect of human behavior based on the calibration of internal models via sensory information such as proprioception. Some conditions, as exercise-induced muscle damage (EIMD), disrupt proprioceptive information, and may cause learning impairment. Such possible relation between EIMD and motor skill learning has not yet been investigated and it is the aim of this study. For this purpose, thirty male university students (19.3 ± 1.8 years) were equally assigned to two groups: EIMD and CON group. The EIMD group received a treatment to induce muscle damage consisting of a weight lifting protocol directed to the agonist muscles related to the task prior to the pretest and to the learning sessions. EIMD was verified and compared between groups and along the process (0–168 h) by means of the degree of delayed onset muscle soreness (DOMS), perceived total quality recovery and maximal isometric strength (MIS). To investigate motor skill learning, both groups practiced a dart throwing task for four sessions with 150 trials in each session. Recovery status and DOMS were recovered at 96 h in the EIMD group, and MIS was not recovered throughout 168 h. In contrast, muscle damage parameters were not altered across 168 h in the CON group. Accuracy and consistency were compared within and between groups in a pretest posttest design. The EIMD group showed less accurate and consistent results on the long term (delayed posttest). Results confirmed our hypothesis that EIMD, a common condition in sports and in rehab practices, may hinder motor skill learning, possibly due to neurological aspects such as proprioceptive information, its relation to central nervous system reorganization and internal model consolidation.     

公民健康权益视野下计划疫苗损害责任之探析

为了促进计划疫苗损害救济的实现, 保障公民健康权益, 基于法的规范分析, 计划疫苗预防接种应是一种具体行政行为, 体现了强制医疗法律关系。接种单位在履行预防接种职责时, 如果造成了受种者损害, 其损害赔偿应属于国家赔偿的范畴。计划疫苗预防接种行政行为损害赔偿责任构成要件具体包括:预防接种行为中的侵权主体属于国家赔偿责任的主体、有违法的预防接种行为、有预防接种法律损害事实、预防接种违法行为和损害后果之间存在因果关系。     

医疗器械致害责任实证调研报告

医疗器械是一种特殊产品。与一般医疗侵权责任和产品侵权责任相比,医疗器械致害责任具有特殊性。通过对法官及其他法律工作者的调查得知:关于医疗器械致害责任的性质,在一般医疗侵权与产品侵权责任之间仍存模糊之处;强制性标准在医疗器械缺陷判断中占有重要地位,但医疗鉴定却起决定性作用;法律工作者对实施《侵权责任法》针对医疗器械的售后跟踪义务规定较乐观,《涉外民事关系法律适用法》对医疗器械致害跨国诉讼的影响不大。     

Percentile Norms and Accompanying Interval Estimates from an Australian General Adult Population Sample for Self‐Report Mood Scales (BAI,BDI, CRSD,CES‐D,DASS, DASS‐21, STAI‐X,STAI‐Y,SRDS, and SRAS)

Despite their widespread use, many self‐report mood scales have very limited normative data. To rectify this, Crawford et al. have recently provided percentile norms for a series of self‐report scales. The present study aimed to extend the work of Crawford et al. by providing percentile norms for additional mood scales based on samples drawn from the general Australian adult population. Participants completed a series of self‐report mood scales. The resultant normative data were incorporated into a computer programme that provides point and interval estimates of the percentile ranks corresponding to raw scores for each of the scales. The programme can be used to obtain point and interval estimates of the percentile ranks of an individual's raw scores on the Beck Anxiety Inventory, the Beck Depression Inventory, the Carroll Rating Scale for Depression, the Centre for Epidemiological Studies Rating Scale for Depression, the Depression, Anxiety, and Stress Scales (DASS), the short‐form version of the DASS (DASS‐21), the Self‐rating Scale for Anxiety, the Self‐rating Scale for Depression, the State–Trait Anxiety Inventory (STAI), form X, and the STAI, form Y, based on normative sample sizes ranging from 497 to 769. The interval estimates can be obtained using either classical or Bayesian methods as preferred. The programme (which can be downloaded at http://www.abdn.ac.uk/~psy086/dept/MoodScore_Aus.htm ) provides a convenient and reliable means of obtaining the percentile ranks of individuals' raw scores on self‐report mood scales.     

Desire for control and optimistic time predictions

Halkjelsvik, T., Rognaldsen, M. & Teigen, K. H. (2012). Desire for control and optimistic time predictions. Scandinavian Journal of Psychology 53, 499–505. Few studies have investigated individual differences in time predictions. We report two experiments that show an interaction between the personality trait Desirability of Control and reward conditions on predictions of performance time. When motivated to perform a task quickly, participants with a strong desire for control produced more optimistic predictions than those with a weaker desire for control. This effect could also be observed for a completely uncontrollable task. The results are discussed in relation to the finding that power produces more optimistic predictions, and extend this work by ruling out some previously suggested explanations.     

Pooling data versus averaging model fits for some prototypical multinomial processing tree models

For a study with multinomial data where there are n_g individuals and with each person having n_r test trials, the question arises as to how to fit the parameters of a multinomial processing tree (MPT) model. Should each parameter be estimated for each individual and then averaged to obtain a group estimate, or should the frequencies in the multinomial categories be pooled so that the model is fit once for the entire group? This basic question is explored with a series of Monte Carlo simulations for some prototypical MPT models. There is a general finding of a pooling advantage for the case where there is a single experimental condition. Also when there are different experimental conditions, there is reduced bias for detecting condition differences for a method based on the pooled data. Although the focus of the paper is on multinomial models, a general theorem is advanced that establishes a basic condition that determines whether there is or is not a difference between the averaging of individual estimates and the estimate based on the pooled data.     

Investigation of the interaction of He and D in FeBSi alloy

He and H can be produced by nuclear reaction. In addition, energetic particles of He and T and D, which are isotopes of H, in the plasma of fusion reactor induce the damage in the surface of materials, such as erosion, sputtering and blistering. To investigate the interaction of He and D, amorphous and crystalline FeBSi alloys were irradiated by He or D₂ or He?+?D₂ ions with 5?keV. The results of thermal desorption indicated that more He atoms were trapped in both the amorphous and crystalline alloy irradiated by He ions than D atoms in those alloys irradiated by D₂ ions. Although He and D atoms were trapped in FeBSi alloy irradiated by He?+?D₂ ions, desorption peaks of D₂ and He were separated. Absorption of D in an amorphous alloy was influenced by the presence of He; however, absorption of He was independent of D₂ irradiation in both alloys.