Reactive and nonreactive scattering of H2 from a metal surface is electronically adiabatic

The Born-Oppenheimer approximation of uncoupled electronic and nuclear motion is a standard tool of the computational chemist. However, its validity for molecule-metal surface reactions, which are important to heterogeneous catalysis, has been questioned because of the possibility of electron-hole pair excitations. We have performed experiments and calculations on the scattering of molecular hydrogen from a catalytically relevant metal surface, obtaining absolute probabilities for changes in the molecule's velocity parallel to the representative Pt(111) surface. The comparison for in-plane and out-of-plane scattering and results for dissociative chemisorption in the same system show that for hydrogen-metal systems, reaction and diffractive scattering can be accurately described using the Born-Oppenheimer approximation.     

不同程度跛行奶牛血浆中E_2、GnRH、FSH和PGF2a的检测与分析

为研究跛行对产后奶牛主要生殖激素的影响,实验采用5分制跛行评价标准,在黑龙江地区某规模化牧场,对产后40 d泌乳牛(未使用任何生殖激素类药物)进行跛行评分,然后对跛行评分为1~5分奶牛血浆样品中的促性腺激素释放激素(Gn RH)、促卵泡生长激素(FSH)、雌二醇(E2)和前列腺素(PGF2a)含量进行测定,分析不同跛行评分奶牛血浆样品中4种激素的变化。共获得49头泌乳奶牛作为研究对象,其中1分为8头,2分为19头,3分为14头,4分为4头,5分为4头。研究结果显示,与健康奶牛相比,随着跛行评分的增加,E2、Gn RH、FSH和PGF2a的含量均呈现不同程度的减少趋势。研究结果提示,跛行能影响奶牛产后主要的生殖激素分泌。     

HTLV-I trans-activator protein, tax, is a trans-repressor of the human beta-polymerase gene

Human T cell leukemia virus type I (HTLV-I) is the etiological agent for adult T cell leukemia (ATL). The HTLV-I trans-activator protein Tax can activate the expression of its own long terminal repeat (LTR) and many cellular and viral genes. Tax down-regulated the expression of human beta-polymerase (hu beta-pol), a cellular enzyme involved in host cell DNA repair. This finding suggests a possible correlation between HTLV-I infection and host chromosomal damage, which is often seen in ATL cells.     

不同工艺提取的蜂胶对2型糖尿病大鼠降血糖作用比较

探讨了采用乙醇提取和超临界萃取的2种蜂胶的降血糖作用,并进行比较研究.将大鼠随机分组后连续9周灌喂蜂胶,每2周测空腹血糖和餐后血糖;于第9周进行糖耐量试验;处死大鼠后,测定其血液中甘油三脂、胆固醇、尿酸、肌酐、尿素氮的含量;解剖大鼠后分别称取其肝、肾重量.结果表明造模后试验组的终重与正常组的差异显著;超临界试验组的糖耐量和胆固醇指标与模型1组的差异显著;其他各项指标的差异均不显著.     

Cellulose metabolism by the flagellate trichonympha from a termite is independent of endosymbiotic bacteria

Continuous axenic cultures were established of Trichonympha sphaerica, a cellulose-digesting symbiotic protozoon in the gut of a termite. The cultured flagellates harbored no endosymbiotic bacteria and metabolized cellulose to acetate, carbon dioxide, and hydrogen. Thus, the cellulolytic activity of this flagellate is an inherent property and is not dependent on endosymbiotic bacteria.     

RIM-binding protein, a central part of the active zone, is essential for neurotransmitter release

The molecular machinery mediating the fusion of synaptic vesicles (SVs) at presynaptic active zone (AZ) membranes has been studied in detail, and several essential components have been identified. AZ-associated protein scaffolds are viewed as only modulatory for transmission. We discovered that Drosophila Rab3-interacting molecule (RIM)-binding protein (DRBP) is essential not only for the integrity of the AZ scaffold but also for exocytotic neurotransmitter release. Two-color stimulated emission depletion microscopy showed that DRBP surrounds the central Ca(2+) channel field. In drbp mutants, Ca(2+) channel clustering and Ca(2+) influx were impaired, and synaptic release probability was drastically reduced. Our data identify RBP family proteins as prime effectors of the AZ scaffold that are essential for the coupling of SVs, Ca(2+) channels, and the SV fusion machinery.     

我国治理公路三乱政策执行中“上有政策,下有对策”的问题分析及对策研究

现今公路三乱问题已经成为一个日趋严重的中国性难题。本文总结了三乱政策执行中上有政策,下有对策现象的表现形式、原因,并提出了相应对策。     

QTL-allele matrix detected from RTM-GWAS is a powerful tool for studies in genetics,evolution, and breeding by design of crops

正The plant germplasm resources harboring abundant genetic variations are necessary wealth in developing new cultivars adapted to various geographic and seasonal conditions. Unraveling the complex genetic architecture underlying phenotypic diversity in germplasm population is essential     

外周型直径<2 cm的T1a期肺腺癌患者发生淋巴结转移相关危险因素分析

目的 分析外周型直径<2 cm的T1a期肺腺癌患者发生淋巴结转移相关危险因素。方法 选取T1a期肺腺癌的患者347例,搜集入选对象的所有临床资料,对于行PET-CT检查的患者,记录最大标准摄取值,记录患者术前CT检查情况并分类,对可能影响淋巴结转移的因素进行单因素分析和Logistic多因素分析。结果 347例患者中位随访时间15.7个月,未出现死亡病例;单因素分析显示,影像学特征为实性结节或混合型、肿瘤直径1.0～2.0 cm、癌胚抗原>5 μg·L-1,以及行PET-CT检查最大标准摄取值(SUV_max)>5是淋巴结发生转移的重要危险因素(P＜0.05),非条件Logistic回归分析显示,影像学特征实性结节和混合型是淋巴结发生转移的独立危险因素(OR=13.642,95%CI:12.943～21.816,P＜0.001);对患者影像学表现与临床病理特征进行分析,影像学表现为纯毛玻璃影的56例患者中,均未发生淋巴结转移,表现为混合型的142例患者,134例(94.4%)未发生淋巴结转移,而表现为实性结节的149例患者,97例(65.1%)未发生淋巴结转移,差异有统计学意义(P＜0.05)。结论 影像学特征为实性结节或部分实性毛玻璃结节是直径<2 cm的T1a期肺腺癌患者发生淋巴结转移的独立危险因素,而影像学特征为纯毛玻璃影的患者一般不存在淋巴结转移。     

The present is not the key to the past: a polar forest from the permian of antarctica

An in situ Upper Permian fossil forest in the central Transantarctic Mountains near the Beardmore Glacier includes 15 permineralized trunks in growth position; the paleolatitude of the site was approximately 80 degrees to 85 degrees south. Numerous leaves of the seed fern Glossopteris are present in the shale in which the trunks are rooted. The trunks are permineralized and tree rings reveal that the forest was a rapidly growing and young forest, persisting in an equable, strongly seasonal climate-a scenario that does not fit with some climate reconstructions for this time period.