延衰合剂对D-半乳糖诱导的亚急性衰老小鼠免疫功能影响的实验研究

目的 研究延衰合剂( yanshuai mixture,YSM)对D-半乳糖所致亚急性衰老小鼠胸腺、脾脏组织结构及白介素2水平的影响.方法 选昆明系小鼠,用D-半乳糖建立衰老模型.应用光镜、电镜技术观察延衰合剂治疗前后衰老小鼠胸腺、脾脏的形态学改变;检测胸腺指数及脾脏指数;酶联免疫分析法检测血清白介素2的变化.结果 衰...     

基于几何统计的无人机信道模型及硬件模拟

针对无人机(unmanned aerial vehicle, UAV)通信信号三维空间传播特点,提出了基于多圆柱体的非平稳几何统计模型(geometry-based stochastic channel model, GSCM),该模型通过引入天线位置变换矩阵,可支持UAV〖JP2〗和地面移动端(mobile terminal,MT)任意三维移动轨迹。在此基础上,构建了适合硬件模拟实现的离散化模型,并设计实现了模拟时变信道特性的随机簇生灭算法,以及基于线性调频叠加原理的非平稳衰落模拟方法。硬件实测结果表明,本文信道模拟器输出的衰落幅值分布、时延功率谱和多普勒功率谱等统计特性与理论结果比较吻合,有效复现了信道时变衰落、多径时延、多径功率和多普勒频率随着UAV的位置和速度变化而变化的过程。     

Melatonin and mitochondrial function during ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury occurs in many organs and tissues, and contributes to morbidity and mortality worldwide. Melatonin, an endogenously produced indolamine, provides a strong defense against IR injury. Mitochondrion, an organelle for ATP production and a decider for cell fate, has been validated to be a crucial target for melatonin to exert its protection against IR injury. In this review, we first clarify the mechanisms underlying mitochondrial dysfunction during IR and melatonin’s protection of mitochondria under this condition. Thereafter, special focus is placed on the protective actions of melatonin against IR injury in brain, heart, liver, and others. Finally, we explore several potential future directions of research in this area. Collectively, the information compiled here will serve as a comprehensive reference for the actions of melatonin in IR injury identified to date and will hopefully aid in the design of future research and increase the potential of melatonin as a therapeutic agent.     

The pathogenesis of cardiac fibrosis

Cardiac fibrosis is characterized by net accumulation of extracellular matrix proteins in the cardiac interstitium, and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. This review discusses the cellular effectors and molecular pathways implicated in the pathogenesis of cardiac fibrosis. Although activated myofibroblasts are the main effector cells in the fibrotic heart, monocytes/macrophages, lymphocytes, mast cells, vascular cells and cardiomyocytes may also contribute to the fibrotic response by secreting key fibrogenic mediators. Inflammatory cytokines and chemokines, reactive oxygen species, mast cell-derived proteases, endothelin-1, the renin/angiotensin/aldosterone system, matricellular proteins, and growth factors (such as TGF-β and PDGF) are some of the best-studied mediators implicated in cardiac fibrosis. Both experimental and clinical evidence suggests that cardiac fibrotic alterations may be reversible. Understanding the mechanisms responsible for initiation, progression, and resolution of cardiac fibrosis is crucial to design anti-fibrotic treatment strategies for patients with heart disease.     

Male-pattern baldness susceptibility locus at 20p11

We conducted a genome-wide association study for androgenic alopecia in 1,125 men and identified a newly associated locus at chromosome 20p11.22, confirmed in three independent cohorts (n = 1,650; OR = 1.60, P = 1.1 x 10(-14) for rs1160312). The one man in seven who harbors risk alleles at both 20p11.22 and AR (encoding the androgen receptor) has a sevenfold-increased odds of androgenic alopecia (OR = 7.12, P = 3.7 x 10(-15)).     

汽轮机通流部分清洗技术在6MW机组中的应用

通过对霍州煤电煤矸石热电厂2#汽轮机组推力瓦温度高原因分析,得出其主要原因为通流部分结垢严重,流通不畅,导致汽轮机做功能力下降,使机组无法带至额定负荷;并对通流部分结垢的原因进行分析、研究,作出清洗处理,有效降低了机组运行中的推力瓦温度,以提高机组的安全经济性。     

Heritable germline epimutation of MSH2 in a family with hereditary nonpolyposis colorectal cancer

Epimutations in the germline, such as methylation of the MLH1 gene, may contribute to hereditary cancer syndrome in human, but their transmission to offspring has never been documented. Here we report a family with inheritance, in three successive generations, of germline allele-specific and mosaic hypermethylation of the MSH2 gene, without evidence of DNA mismatch repair gene mutation. Three siblings carrying the germline methylation developed early-onset colorectal or endometrial cancers, all with microsatellite instability and MSH2 protein loss. Clonal bisulfite sequencing and pyrosequencing showed different methylation levels in different somatic tissues, with the highest level recorded in rectal mucosa and colon cancer tissue, and the lowest in blood leukocytes. This mosaic state of germline methylation with different tissue distribution could act as the first hit and provide a mechanism for genetic disease inheritance that may deviate from the mendelian pattern and be overlooked in conventional leukocyte-based genetic diagnosis strategy.     

两个“烧结”一个也不能少

“烧结”在矿物工程和粉末冶金两个学科领域都是核心名词，尽管两类烧结都是通过高温改变物料的凝聚状态，但已分别被赋予了互不相同的内涵，存在着一系列本质上的差别，不能相互取代。在汇编冶金学基本名词时，两个“烧结”应该分别列出，一个也不能少。     

不同侵蚀强度下崩岗表层土壤稀土元素分布特征及影响因素

崩岗是我国南方亚热带地区分布最为严重的土壤侵蚀类型,其发育的速度和强度对地表产生巨大破坏作用,同时对土壤中稀土元素的含量和分布产生重要影响.文章通过野外取样调查和室内ICP-MS测定,对福建省长汀县濯田镇黄泥坑崩岗群内3个不同侵蚀崩岗各部位表层土壤(0~10cm)进行取样研究.结果表明稀土元素总量变化依次为轻度侵蚀区中度侵蚀区强度侵蚀区,且轻稀土元素含量富集;不同侵蚀程度的崩岗的稀土元素含量变化基本呈现沿集水区到沟道逐步增加的趋势;其中,元素Ce元素含量极高,Eu元素含量低,有明显的亏损现象;植被覆盖条件好的区域表层土壤中稀土元素含量高.