Negtive selection plays a very important role in maturate of T cell.

阴性选择是幼稚T细胞在分化发育过程中一个非常重要的步骤。

Results: Incidence of nosocomial lung infection was as high as 85.7% with Gram negtive bacteria species as main pathogen.

结果：脑出血患者并发医院内肺部感染的几率极高。 以G-菌多见，占85.7%。

BCG antigen was also positive in all the 20 multibacillary leprosy cases, 28/30 paucibacillary leprosy cases, 8/9 other mycobacterial or fungal cases, negtive in the 10 non-infectious cases.

BCG抗原20例多菌型麻风全部阳性，30例少菌型麻风中28例阳性，9例其他分支杆菌、真菌病中8例阳性，10例非感染性皮肤病未见表达。

Most coal selecting plant for power use have difficulties in simple tech. , single structure, wed capacity in market and negtive ability in meeting the requirements for environment protection.

动力煤选煤厂大多存在洗选工艺简单、产品结构不灵活、难以适应煤炭市场及环保要求的现状。