Evening light exposure to computer screens disrupts human sleep,biological rhythms,and attention abilities

The use of electronic devices with light-emitting screens has increased exponentially in the last decade. As a result, humans are almost continuously exposed to unintentional artificial light. We explored the independent and combined effects of two aspects of screen illumination, light wavelength, and intensity, on sleep, its biological regulation, and related functional outcomes. The 2 × 2 repeated-measure design included two independent variables: screen light intensity (low ([LI] versus high [HI]) and wavelength (short [SWL] versus long [LWL]). Nineteen participants (11F, 8M; mean age 24.3 [±2.8] years) underwent four light conditions, LI/SWL, HI/SWL, LI/LWL, and HI/LWL, in counterbalanced order. Each light exposure lasted for two hours (21:00–23:00), following which participants underwent an overnight polysomnography. On each experimental night, oral temperature and urine samples (for melatonin analysis) were collected at multiple time points. Each morning, participants filled out questionnaires and conducted a computerized attention task. Irrespective of light intensity, SWL illumination significantly disrupted sleep continuity and architecture and led to greater self-reported daytime sleepiness. SWL light also altered biological rhythms, subduing the normal nocturnal decline in body temperature and dampening nocturnal melatonin secretion. Light intensity seemed to independently affect sleep as well, but to a lesser degree. Both light intensity and wavelength negatively affected morning attention. In sum, light wavelength seems to have a greater influence than light intensity on sleep and a wide-range of biological and behavioral functions. Given the widespread use of electronic devices today, our findings suggest that screen light exposure at evening may have detrimental effects on human health and performance.     

The biodiversity‐dependent ecosystem service debt

Habitat destruction is driving biodiversity loss in remaining ecosystems, and ecosystem functioning and services often directly depend on biodiversity. Thus, biodiversity loss is likely creating an ecosystem service debt: a gradual loss of biodiversity‐dependent benefits that people obtain from remaining fragments of natural ecosystems. Here, we develop an approach for quantifying ecosystem service debts, and illustrate its use to estimate how one anthropogenic driver, habitat destruction, could indirectly diminish one ecosystem service, carbon storage, by creating an extinction debt. We estimate that c. 2–21 Pg C could be gradually emitted globally in remaining ecosystem fragments because of plant species loss caused by nearby habitat destruction. The wide range for this estimate reflects substantial uncertainties in how many plant species will be lost, how much species loss will impact ecosystem functioning and whether plant species loss will decrease soil carbon. Our exploratory analysis suggests that biodiversity‐dependent ecosystem service debts can be globally substantial, even when locally small, if they occur diffusely across vast areas of remaining ecosystems. There is substantial value in conserving not only the quantity (area), but also the quality (biodiversity) of natural ecosystems for the sustainable provision of ecosystem services.     

罗氏沼虾繁殖行为的再描述

2007年6～9月对采自孟加拉国库尔纳专区羌纳县布苏尔河原产地罗氏沼虾(Macrobrachium rosenbergii)的繁殖行为进行了观察研究。配合摄像机录像技术,重点观察并记录了野生罗氏沼虾生殖过程中的主要行为特征。本文所涉及的繁殖过程特指在人工操控条件下,自两性遭遇、识别至雌虾抱卵为止这段时间。选择体重在80.0g以上的雄虾、40.0g以上的雌虾分别在当地河堤外侧的池沼中驯化适应15d,然后,在室内水泥池中观察其繁殖行为。罗氏沼虾在繁殖过程中呈现的典型行为主要有:两性遭遇及识别,雄虾的占位,雌虾的蜕壳,雄虾俘获雌虾及其交媾前的守卫、交媾及精荚传递,雄虾交媾后的守卫及释放雌虾,雌虾产卵及抱卵。其中,雄虾的配偶守卫行为是有效地保证两性生殖成功的交配策略之一。     

RNA干扰在昆虫中的作用机理及应用进展

RNA干扰（RNAi）是生物体内源基因发生转录后特异性降解的一种生理现象,作为抵抗病毒的免疫机制,广泛存在于生物体内。RNAi在秀丽隐杆线虫中的发生机制已明确,但昆虫的系统性RNAi不同于线虫,在昆虫中尚未发现线虫跨膜蛋白SID．2的同源蛋白,且果蝇中不存在依赖于RNA的RNA聚合酶（RdRP）,但存在具有相似活性的物质。昆虫发生RNAi的效率不仅与靶标基因自身及双链RNA的选择有关,而且与虫体的发育状态及摄入双链RNA的剂量相关。随着RNAi在昆虫中作用特点的阐明,RNAi的应用价值也逐渐体现。近年来,通过RNAi沉默靶标基因,不但促进了昆虫基因功能研究的发展,而且被广泛用于重要农业害虫抗药性基因的研究。最新研究表明,RNAi结合第2代测序技术,针对非模式昆虫,能迅速找到具有致死效应的靶标序列,加快了利用RNAi技术生产生物农药的步伐。     

Wild‐type p53 enhances endothelial barrier function by mediating RAC1 signalling and RhoA inhibition

Inflammation is the major cause of endothelial barrier hyper‐permeability, associated with acute lung injury and acute respiratory distress syndrome. This study reports that p53 “orchestrates” the defence of vascular endothelium against LPS, by mediating the opposing actions of Rac1 and RhoA in pulmonary tissues. Human lung microvascular endothelial cells treated with HSP90 inhibitors activated both Rac1‐ and P21‐activated kinase, which is an essential element of vascular barrier function. 17AAG increased the phosphorylation of both LIMK and cofilin, in contrast to LPS which counteracted those effects. Mouse lung microvascular endothelial cells exposed to LPS exhibited decreased expression of phospho‐cofilin. 17AAG treatment resulted in reduced levels of active cofilin. Silencing of cofilin pyridoxal phosphate phosphatase (PDXP) blocked the LPS‐induced hyper‐permeability, and P53 inhibition reversed the 17AAG‐induced PDXP down‐regulation. P190RHOGAP suppression enhanced the LPS‐triggered barrier dysfunction in endothelial monolayers. 17AAG treatment resulted in P190RHOGAP induction and blocked the LPS‐induced pMLC2 up‐regulation in wild‐type mice. Pulmonary endothelial cells from “super p53” mice, which carry additional p53‐tg alleles, exhibited a lower response to LPS than the controls. Collectively, our findings help elucidate the mechanisms by which p53 operates to enhance barrier function.     

Steps for the Autologous Ex vivo Perfused Porcine Liver-kidney Experiment

The use of ex vivo perfused models can mimic the physiological conditions of the liver for short periods, but to maintain normal homeostasis for an extended perfusion period is challenging. We have added the kidney to our previous ex vivo perfused liver experiment model to reproduce a more accurate physiological state for prolonged experiments without using live animals. Five intact livers and kidneys were retrieved post-mortem from sacrificed pigs on different days and perfused for a minimum of 6 hr. Hourly arterial blood gases were obtained to analyze pH, lactate, glucose and renal parameters. The primary endpoint was to investigate the effect of adding one kidney to the model on the acid base balance, glucose, and electrolyte levels. The result of this liver-kidney experiment was compared to the results of five previous liver only perfusion models. In summary, with the addition of one kidney to the ex vivo liver circuit, hyperglycemia and metabolic acidosis were improved. In addition this model reproduces the physiological and metabolic responses of the liver sufficiently accurately to obviate the need for the use of live animals. The ex vivo liver-kidney perfusion model can be used as an alternative method in organ specific studies. It provides a disconnection from numerous systemic influences and allows specific and accurate adjustments of arterial and venous pressures and flow.     

蒙古野驴的繁殖行为观察

2014年6月至2015年8月期间,对分布在内蒙古自治区包头市达尔罕茂明安联合旗中蒙边境地区(41°14′~42°40′N,109°16′~110°26′E)和内蒙古自治区巴彦淖尔市乌拉特梭梭林-蒙古野驴国家级自然保护区(41°50′~42°27′N,106°15′~108°00′E)的两个野驴群(1♂3♀和2♂3♀)的繁殖行为进行研究。采用目标取样法以及目标取样法与扫描取样法相结合的方法对蒙古野驴的发情交配、产前反应、生产过程及产后行为进行观察。共记录到4类35种繁殖行为,分别为争斗行为、性行为、分娩行为和母幼联系行为。结果表明,雄驴平均日爬跨(4.2±1.7)次(n=14),射精(3.7±1.3)次(n=13),平均邀配持续时间(从雌雄驴靠近调情始到爬跨或其中一个走开止)为(26.6±22.0)s(n=13),平均抽动持续时间为(10.6±1.9)s(n=14),平均阴茎置入持续时间为(18.3±8.8)s(n=13),平均爬跨间隔为(685.7±569.6)s(n=14),平均射精间隔为(924.0±790.0)s(n=10)。蒙古野驴的交配模式属于Dewsbury分类系统中的第11种(无锁结、有抽动、单次插入、多次射精)类型和Dixon分类系统中的第12种(无锁结、有抽动、单次插入、无单次长时间插入)类型。本研究较完整地建立了蒙古野驴繁殖行为谱,提供了繁殖行为方面的基础资料。     

小儿肺热咳喘口服液联合阿奇霉素对肺炎支原体肺炎患儿肺功能和炎性因子的影响

目的:探讨小儿肺热咳喘口服液联合阿奇霉素对肺炎支原体肺炎患儿肺功能和炎性因子的影响。方法:选取2016年1月～2017年12月期间我院收治的175例肺炎支原体肺炎患儿,根据随机数字表法将其分为对照组(n=87,阿奇霉素治疗)和研究组(n=88,小儿肺热咳喘口服液联合阿奇霉素治疗),比较两组患儿临床疗效、临床症状消失时间、肺功能指标[第1s用力呼气容积(FEV1)、用力肺活量(FVC)、FEV1/FVC]、炎性因子指标[肿瘤坏死因子-α(TNF-α)、白介素-6(IL-6)、C反应蛋白(CRP)],记录两组患儿不良反应发生情况。结果:研究组患儿治疗后临床总有效率为94.32%(83/88),高于对照组患儿的80.46%(70/87)(P0.05)。研究组患儿咳嗽、发热、湿啰音、哮鸣音的消失时间均短于对照组(P0.05)。两组患儿治疗后FEV1、FVC、FEV1/FVC均升高,且研究组高于对照组(P0.05)。两组患儿治疗后IL-6、CRP、TNF-α水平均降低,且研究组低于对照组(P0.05)。两组患儿不良反应发生率对比无统计学差异(P0.05)。结论:小儿肺热咳喘口服液联合阿奇霉素治疗肺炎支原体肺炎患儿的疗效优于单用阿奇霉素,且可有效改善患儿肺功能和炎性因子水平,快速缓解临床症状,促进患儿恢复。     

Sex‐related spatial patterns of Poa ligularis in relation to shrub patch occurrence in northern Patagonia

Abstract. Poa ligularis is a dioecious species and a valuable forage plant which is widespread in the arid steppe of northern Patagonia (Argentina). The vegetation in these areas consists of a system of perennial plant patches alternating with bare soil areas defining contrasting micro‐environments. We hypothesized that (1) male and female individuals of P. ligularis are spatially segregated in different micro‐environments, (2) the intensity of spatial segregation of sexes depends on plant structure and (3) spatial segregation of sexes is enhanced by competitive interactions between the sexes within the vegetation patches. We analysed the spatial distribution of female and male individuals in relation to the spatial pattern of vegetation in two areas differing in their vegetation structure. The location of P. ligularis within patches where either male, female or both sexes occurred was also analysed. The results indicate that different patterns of spatial distribution of sexes of P. ligularis may be found at the community level depending on the dominant life forms and geometric structure of plant patches. Where patches are of a lower height, with a high internal patch cover, individuals of both sexes are concentrated within patch canopies. In sites characterized by large, tall patches and less internal patch cover suitable microsites for female and male P. ligularis occur both within and outside the patch with males located at further distances from the patch edge. Where the patch is large and tall enough to allow the establishment of males and females at relatively high numbers, males occupy the patch periphery or even colonize the interpatch bare soil. These spatial patterns are consistent with selective traits in which females better tolerate intraspecific competition than males, while males tolerate wider fluctuations in the physical environment (soil moisture, nitrogen availability, wind intensity, etc.).     

Dielectric Properties of the Plasma Membrane of Cultured Murine Fibroblasts Treated with a Nonterpenoid Extract of Azadirachta indica Seeds

Neem oil is a natural product obtained from the seeds of the tree Azadirachta indica. In this report, we investigate the alterations of the biophysical properties of the plasma membrane caused by treatment with the nonterpenoid fraction of neem oil that we defined as methanolic extract (MEX). The dose-response effect was evaluated and a MEX-dependent cytoxicity evidenced. The effect of MEX on the plasma membrane was studied by a well-established dielectric spectroscopy technique: electrorotation, which allows single-cell analysis. Our results show a structural/functional alteration of the plasma membrane with an evident increase of specific capacitance and conductance. The biological implications of this effect are discussed.