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.     

非洲猪瘟病毒微滴数字PCR (ddPCR)方法的建立及应用

【目的】非洲猪瘟病毒(African swine fever virus,ASFV)能导致猪群高死亡率,从而造成严重的经济损失。因此,建立严密、高效的防控系统,包括灵敏、准确的诊断方法以及高效的预报预警机制等,以避免ASF传入我国。本文旨在建立一种新型而高灵敏度的ASFV微滴数字PCR(Droplet digital PCR,dd PCR)检测方法。【方法】针对ASFV K205R基因设计一对特异性引物和Taq Man探针,通过反应条件优化,建立了ASFV实时荧光定量PCR(q PCR)和dd PCR检测方法;并对两种方法的线性关系、灵敏性、特异性和重复性进行了评估,利用建立的ASFV检测方法对163份国内和进境的组织样本及血清样本进行检测,血清样本经商品化ASFV ELISA试剂盒复检,评估不同方法检测结果的符合率。【结果】建立的ASFV q PCR和dd PCR检测方法线性关系较好(R2≥0.998),dd PCR的最低检测限度可达到0.36拷贝,在20μL反应体系中约为10拷贝/反应,检测灵敏度是q PCR的10倍。ASFV dd PCR检测方法具有很高的特异性和重复性,不与其他猪常见病毒发生交叉反应。【结论】该方法灵敏度高、特异性强,可作为一种有效的分子生物学方法来诊断ASFV,为防止该病传入我国以及ASFV的实时监测提供新的技术储备,同时促进dd PCR技术在我国的发展和应用。     

Quantitative IR microscopy and spectromics open the way to 3D digital pathology

Currently, only mass‐spectrometry (MS) microscopy brings a quantitative analysis of chemical contents of tissue samples in 3D. Here, the reconstruction of a 3D quantitative chemical images of a biological tissue by FTIR spectro‐microscopy is reported. An automated curve‐fitting method is developed to extract all intense absorption bands constituting IR spectra. This innovation benefits from three critical features: (1) the correction of raw IR spectra to make them quantitatively comparable; (2) the automated and iterative data treatment allowing to transfer the IR‐absorption spectrum into a IR‐band spectrum; (3) the reconstruction of an 3D IR‐band matrix (x, y, z for voxel position and a 4^th dimension with all IR‐band parameters). Spectromics, which is a new method for exploiting spectral data for tissue metadata reconstruction, is proposed to further translate the related chemical information in 3D, as biochemical and anatomical tissue parameters. An example is given with oxidative stress distribution and the reconstruction of blood vessels in tissues. The requirements of IR microscopy instrumentation to propose 3D digital histology as a clinical routine technology is briefly discussed.

     

扩散型与繁殖型松材线虫数字基因表达谱对比分析

【目的】松材线虫作为林业重大外来入侵种,扩散型幼虫的形成对其传播扩散起着非常重要的作用,但扩散虫态的形成与维持机制尚未阐明。【方法】通过构建松材线虫数字基因表达谱(DGE),从滞育状态的维持、化学感受、代谢途径等方面分析松材线虫不同虫态的基因表达差异。【结果】参考松材线虫基因组数据,鉴定出2种扩散型幼虫(LⅢ,LⅣ)和繁殖型幼虫(Ln)各有11184、8533和10781个基因。相对于繁殖型虫态,大多数基因在LⅣ中下调表达,该虫态中特异上调表达的基因有化感受体基因、核受体基因以及一些代谢相关基因。推测这可能与扩散型线虫滞育状态的维持相关,并在其生理功能如化学感受和媒介/寄主互作中发挥作用。GO和Pathway富集分析显示,多数代谢相关通路在LⅣ中下调表达,而在LⅢ中的表达均活跃。【结论】以上结果与LⅣ处于不进食、总体代谢水平较低等生理状态的表型相一致。     

Dermatoglyphic asymmetry and diversity in some pathologies

The evaluation of dermatoglyphic asymmetry represents a specific estimate of the stability of intrauterine development. In the present study, we analyzed the level of asymmetry and diversity in the radial and ulnar counts of each finger in 400 health Sardinian individuals and in 469 Sardinian subjects with four common diseases in Sardinia: type 1 diabetes, type 2 diabetes, arterial hypertension and multiple sclerosis. To measure the asymmetry, we used three indices: fluctuating asymmetry, the index of asymmetry and the index of diversity. The differences from the control group are only rarely significant. The values of fluctuating asymmetry do not present a particular distribution in relation to the pathologies, while the values of {ie139-1} and diversity are usually higher in the pathological groups. The differentiation is especially evident in the subjects with multiple sclerosis, intermediate in the diabetics and practically nil in the hypertense individuals.     

数字照片在树干解析上的应用

介绍了一种利用摄影测量技术开展树干解析的新方法.通过求算横截面积,换算成理论直径及年轮宽度.此法可以提高测量精度,特别是在树干横截面不规则的情况下,可以提高准确度.选择一个基本圆满的圆盘,直接测量直径和由面积换算比较年轮宽度,二者差异平均为10%,最大达32%.由于图像上直接测量的是面积,树皮的横截面可以更加准确获得,而传统的方法无法克服这个缺点.数字照片还是储存年轮信息的理想形式,便于保存和复查.本法使用的是普通的数码照片,方便适用,是开展森林精密测量简单易行手段.     

Estimation of walrus populations on sea ice with infrared imagery and aerial photography

Population sizes of ice‐associated pinnipeds have often been estimated with visual or photographic aerial surveys, but these methods require relatively slow speeds and low altitudes, limiting the area they can cover. Recent developments in infrared imagery and its integration with digital photography could allow substantially larger areas to be surveyed and more accurate enumeration of individuals, thereby solving major problems with previous survey methods. We conducted a trial survey in April 2003 to estimate the number of Pacific walruses (Odobenus rosmarus divergens) hauled out on sea ice around St. Lawrence Island, Alaska. The survey used high altitude infrared imagery to detect groups of walruses on strip transects. Low altitude digital photography was used to determine the number of walruses in a sample of detected groups and calibrate the infrared imagery for estimating the total number of walruses. We propose a survey design incorporating this approach with satellite radio telemetry to estimate the proportion of the population in the water and additional low‐level flights to estimate the proportion of the hauled‐out population in groups too small to be detected in the infrared imagery. We believe that this approach offers the potential for obtaining reliable population estimates for walruses and other ice‐associated pinnipeds.     

基于PC声卡的生物医学电信号采集方法

把生物医学电信号以线性调幅的方法调制在音频载波信号之上,用PC声卡采集该已调波信号,用软件实现调幅波的解调,经数字低通滤波器的滤波,恢复出生物医学电信号,达到采集和显示生物医学电信号的的目的。实践证明,该方法具有成本低、多通道工作实时性好的特点,具有实用价值。     

3D analysis from micro-MRI during in situ compression on cancellous bone

A mini-compression jig was built to perform in situ tests on bovine trabecular bone monitored by micro-MRI. The MRI antenna provided an isotropic resolution of 78 μm that allows for a volume correlation method to be used. Three-dimensional displacement fields are then evaluated within the bone sample during the compression test. The performances of the correlation method are evaluated and discussed to validate the technique on trabecular bone. By considering correlation residuals and estimates of acquisition noise, the measured results are shown to be trustworthy. By analyzing average strain levels for different interrogation volumes along the loading direction, it is shown that the sample size is less than that of a representative volume element. This study shows the feasibility of the 3D-displacement and strain field analyses from micro-MRI images. Other biological tissues could be considered in future work.