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71.
The formation and the deexcitation of the composite nucleus formed during the Ni + Al reaction at 28 A·MeV has been studied with the 4 π multidetector AMPHORA. A rigourous selection of the experimental data is described in order to extract a central collision sample. Then different models are compared to the data. The incomplete fusion process is in agreement with the data. The azimuthal angle correlations of He-Li and Li-Li pairs have been used to discriminate sequential or instantaneous emission. The sequential deexcitation is more consistent with all the data. The different analyses allow to describe all the characteristics of the compound nucleus and finally a fusion cross section of 300 ± 100 mbarn has been measured. Received: 11 February 1998 / Revised version: 1 August 1998  相似文献   
72.

Background  

Mycobacterium bovis BCG vaccine has displayed inconsistent efficacy in different trials conducted in various geographical regions. Nevertheless, it significantly reduces the risk of severe childhood tuberculosis and continues to be used to prevent tuberculosis in many countries. Many studies revealed that efficacy of vaccine wanes with age. Most of the studies were based on in vivo and in vitro responses to tuberculin. With the advent of newer tests such as in vitro interferon-γ assays and identification of potent immunogenic mycobacterial proteins there is a need to corroborate the observations. This study aims at ascertaining the need for a booster at a later age as indicated by in vitro release of IFN-γ while evaluating Ag85A as an antigen.  相似文献   
73.
Resveratrol (RVS) is a naturally occurring antioxidant, able to display an array of biological activities. In the present investigation, a new derivative of RVS, RVS(a), was synthesized, and its biological activity was determined on U937 cells. It was observed that RVS(a) showed pronounced activity on U937 cells than RVS. RVS(a) is able to induce apoptosis in tumor cell lines through subsequent DNA fragmentation. From the EMSA results, it was evident that RVS(a) was able to suppress the activity of NFkB by interfering its DNA binding ability. Furthermore, the molecular interaction analysis (docking and dynamics) stated that RVS(a) has strong association with the IkB-alpha site of NFkB compared with RVS; this binding nature of RVS(a) might be prevent the NFkB binding ability with DNA. The present findings represent the potential activity of propynyl RVS on U937 cells and signifying it as a one of putative chemotherapeutic drugs against cancer.  相似文献   
74.

Background  

Multiple neuropeptides, sometimes with opposing functions, can be produced from one precursor gene. To study the roles of the different neuropeptides encoded by one large precursor we developed a method to overexpress minigenes and establish local secretion.  相似文献   
75.
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