Fluctuation and response in biology

In 1905, Albert Einstein proposed that the forces that cause the random Brownian motion of a particle also underlie the resistance to macroscopic motion when a force is applied. This insight, of a coupling between fluctuation (stochastic behavior) and responsiveness (non-stochastic behavior), founded an important branch of physics. Here we argue that his insight may also be relevant for understanding evolved biological systems, and we present a ‘fluctuation–response relationship’ for biology. The relationship is consistent with the idea that biological systems are similarly canalized to stochastic, environmental, and genetic perturbations. It is also supported by in silico evolution experiments, and by the observation that ‘noisy’ gene expression is often both more responsive and more ‘evolvable’. More generally, we argue that in biology there is (and always has been) an important role for macroscopic theory that considers the general behavior of systems without concern for their intimate molecular details.     

Common variants at 11q12, 10q26 and 3p11.2 are associated with prostate cancer susceptibility in Japanese

We have previously reported multiple loci associated with prostate cancer susceptibility in a Japanese population using a genome-wide association study (GWAS). To identify additional prostate cancer susceptibility loci, we genotyped nine SNPs that were nominally associated with prostate cancer (P < 1 × 10(-4)) in our previous GWAS in three independent studies of prostate cancer in Japanese men (2,557 individuals with prostate cancer (cases) and 3,003 controls). In a meta-analysis of our previous GWAS and the replication studies, which included a total of 7,141 prostate cancer cases and 11,804 controls from a single ancestry group, three new loci reached genome-wide significance on chromosomes 11q12 (rs1938781; P = 1.10 × 10(-10); FAM111A-FAM111B), 10q26 (rs2252004; P = 1.98 × 10(-8)) and 3p11.2 (rs2055109; P = 3.94 × 10(-8)). We also found suggestive evidence of association at a previously reported prostate cancer susceptibility locus at 2p11 (rs2028898; P = 1.08 × 10(-7)). The identification of three new susceptibility loci should provide additional insight into the pathogenesis of prostate cancer and emphasizes the importance of conducting GWAS in diverse populations.     

高压抗噪声干扰MOS栅驱动电路的设计

设计了一种高压抗噪声干扰MOS栅驱动电路,能有效抑制开关转换过程中产生的dv/dt噪声,消除高压电路工作过程中可能出现的误触发,提高系统的稳定性和可靠性.采用共模反馈从而使电路结构简单,同时采用窄脉冲触发式控制降低了功耗.本电路可以集成在高压集成电路(HVIC)中.采用某公司高压600V0.5μm BCD工艺模型,通过Cadence仿真验证表明:本电路可有效滤除dv/dt噪声,被消除的dv/dt噪声最高可以达到60V/ns,同时被消除的失调噪声可以达到20%,保证了高压栅驱动电路稳定、可靠地工作.     

放牧对荒漠草原群落多样性的影响

退化草地生态系统中物种多样性的严重丧失及其后果,至今仍缺乏有代表性的实验结论.放牧是人类施加于草原生态系统最主要的干扰因素,从荒漠草原群落多样性、植物功能群多样性以及物种多样性与生产力的关系3个方面综述相关研究进展.提出不同放牧制度对荒漠草原群落多样性、植物功能群多样性的影响过程和作用机制是研究荒漠草原利用与保护平衡的...     

四川盆地须二段储层孔隙演化定量描述

我国低渗透气藏产气量在天然气总产量中所占比例越来越大,研究低渗透气藏的形成机理及形成过程是非常必要的。四川盆地上三叠统须家河组二段是重要的含气层位,但由于其储层具有非均质性强、且具低孔低渗的特点,不仅储层预测难度大,而且开发的效果也差。因此需要研究其形成过程,提高储层预测精度以改善开发效果。以储层岩石学特征、孔隙类型及分布特征、胶结物充填次序及充填时间等研究为基础,定时、定量地研究孔隙的整个演化历史,描述了孔隙在不同历史阶段的大小及变化原因,从而再现了储层形成历史,为下一步须二段气藏有效储层的预测与有效开发打下基础。     

纵倾角对筒基平台气浮拖航影响模型试验研究

以某四筒一简型基础平台为对象,就不同后倾纵倾角（后倾角）拖航组合,采用1：20的模型进行顺浪和逆浪下的拖航试验．通过测定各试验组合拖航过程中平台运动加速度、筒内气压力、筒底水压力以及拖缆力变化,并对试验数据进行对比分析,得到纵倾角对筒型基础平台拖航基本力学参数的影响,进而得出其对平台拖航稳性的影响．结果表明：设置一定的后倾角,可明显降低筒型基础平台拖航时的摇摆以及升沉运动的幅度,但后倾角对提高平台拖航稳性是有限的,与逆浪拖航相比,后倾角对平台顺浪拖航影响较大．对于该四筒一筒型基础平台,在顺浪和逆浪拖航中,当设置1。的后倾角时,平台的拖航稳性和耐波性均最高．     

低温固相反应法合成ZnO纳米晶体

乙酸锌和草酸为原料,采用低温固相反应法制备纳米了ZnO。采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、傅里叶红外光谱仪(FT-IR),光致发光（PL)光谱对所制备的纳米ZnO进行了表征。结果表明：制备的纳米ZnO的粒径为15~25nm左右,六方晶系纤锌矿结构,形貌为类球形。研究了改变工艺条件中研磨时间和水浴温度对合成样品的结构、形貌的影响。发现随着研磨时间的延长,样品的结晶性增强。水浴温度的变化对纳米粒子的结晶性及尺寸有一定的影响。纳米氧化锌由于其对紫外线的高吸收率和可将紫外线转换为可见光而作为近紫外LED光转换材料有着潜在的应用。     

Dysfunction of lipid sensor GPR120 leads to obesity in both mouse and human

Free fatty acids provide an important energy source as nutrients, and act as signalling molecules in various cellular processes. Several G-protein-coupled receptors have been identified as free-fatty-acid receptors important in physiology as well as in several diseases. GPR120 (also known as O3FAR1) functions as a receptor for unsaturated long-chain free fatty acids and has a critical role in various physiological homeostasis mechanisms such as adipogenesis, regulation of appetite and food preference. Here we show that GPR120-deficient mice fed a high-fat diet develop obesity, glucose intolerance and fatty liver with decreased adipocyte differentiation and lipogenesis and enhanced hepatic lipogenesis. Insulin resistance in such mice is associated with reduced insulin signalling and enhanced inflammation in adipose tissue. In human, we show that GPR120 expression in adipose tissue is significantly higher in obese individuals than in lean controls. GPR120 exon sequencing in obese subjects reveals a deleterious non-synonymous mutation (p.R270H) that inhibits GPR120 signalling activity. Furthermore, the p.R270H variant increases the risk of obesity in European populations. Overall, this study demonstrates that the lipid sensor GPR120 has a key role in sensing dietary fat and, therefore, in the control of energy balance in both humans and rodents.     

物理教学中衍射物倾斜时的夫琅和费衍射研究

本文以矩形孔为例，给出了物体平面相对系统光轴倾斜时夫琅和费衍射场的理论计算。