阴性的

With this in mind, the researchers then reanalysed data from knowingly HIV-positive heterosexual subjects in Uganda and Zambia who had HIV-negative sexual partners. Those with a viral load of one million particles per millilitre were more than ten times more likely to accidentally infect their partners each year than those with a load of one thousand.But when the researchers calculated the transmission potential over the entire predicted asymptomatic period, those with viral loads between ten thousand and a hundred thousand copies per millilitre of blood were the most likely to infect their partners. HIV-positive subjects with viral counts of 50,000 infected roughly twice as many people as those with counts of one million.

伦敦帝国学院流行病学家Christophe Fraser和他的同事对收集于1982年到1993年之间的100多例HIV阳性的男性同性恋者的数据进行分析，并结合分析来自乌干达和赞比亚的已知有HIV阴性性伴侣的HIV阳性异性恋受调查者的资料，他们发现中度病毒负荷而无症状的HIV携带者更易播散HIV，这是因为中度病毒负荷的HIV携带者的无症状期较长，而那些高病毒负荷而无症状的HIV携带者虽然传染性稍强，但其传染的持续时间却很短，并且在未经治疗的HIV携带者个体中中度病毒负荷是最常见的人群。

objective the aim of this study is to investigate the expression and the distribution of the nerve growth factor during the period of neural tube development of human embryo.method early development of neural tube was studied in human embryos about 35 gestational days by using immunocytochemical abc technique.result there were ngf immuno-positive substances in the cytoplasm and nuclei of neuroepithelial cells in the ventricular zones of neural tube.in the intermediate zone of neural tube,ngf immunoreactivity was detected in the nuclei of some neurons,or the processes of other neurons which contained no ngf-immunoreactive substances in their nuclei;the expression pattern of ngf in the marginal zone of neural tube was similar to that of the intermediate zone.the density of ngf-immunorecative particles was higher on the rostrum side of neural tube than on the caudal side.the ngf immuno-positive cells were also observed among the somites of embryo under the neural tube.conclusion these results suggest that ngf was an important signal molecule to induce neural tube differentiation,and that ngf may play a significant role in regulation of the biological function of neurons in developing neural tube.

目的 研究捷安肽素的抗真菌作用机理。方法采用形态学方法和同位素标记法。显微形态观察经捷安肽素处理后的供试真菌的形态学变化。进一步采用14c同位素标记的特异底物&尿苷二磷酸-（14c）-葡萄糖&示踪，研究捷安肽素对真菌(1，3)-β-d-葡聚糖合成酶活性反应的影响。结果研究神经生长因子在早期人胚神经管发育过程中的定位表达。方法采用免疫细胞化学 abc法染色，研究35天人胚的发育情况。结果在人胚神经管的室管带中，神经元的细胞质和细胞核ngf免疫反应阳性；在中间带，一部分神经元的细胞核ngf免疫反应阳性，另外一部分神经元的细胞核ngf免疫反应阴性，而其突起ngf免疫反应阳性；在边缘带ngf的表达与中间带相似。在神经管的头侧ngf阳性反应较强，神经管的尾侧ngf阳性反应较弱。结论 ngf在人胚神经管免疫反应阳性，表明ngf可能是诱导神经管分化发育的重要信号分子，提示ngf可能在人胚神经管的发育中具有十分重要的作用。神经生长因子；人胚；神经管；发育

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。