Development of vaccines against tuberculosis

Development of an effective vaccine against tuberculosis (TB) hinges on an improved understanding of the human immune responses to Mycobacterium tuberculosis. A successful vaccination strategy should be able to stimulate the appropriate arm of the immune system with concomitant generation of the memory cells. In the absence of a perfect strategy, while long term efforts of TB researchers continue to resolve the nature of protective immunity against TB and other related issues, the current approach, dictated by the urgency of a TB vaccine, employs available knowledge and technology to develop new TB vaccines and channel the promising ones to clinical trials. While Indian scientists have contributed in several areas towards the development of a TB vaccine, this review is an attempt to summarize their contributions mainly pertaining to the discovery of new antigens, immune responses elicited by antigens against TB and development of new vaccines and their evaluation in animal models. (C) 2011 Elsevier Ltd. All rights reserved.

Characterization of phase transformation behaviour and microstructural development of electroless Ni-B coating

Phase transformation behaviour of amorphous electroless Ni-B coating with a targeted composition of Ni-6wt% B is characterized in conjunction with microstructural development and hardness. Microscopic observations of the as-deposited coating display a novel microstructure which is already phase separated at multiple length scales. Spherical colonies of similar to 5 mu m consist of 2-3 mu m nodular regions which are surrounded by similar to 2-3 mu m region that contains fine bands ranging from 10 to 70 nm in width. The appearance of three crystalline phases in this binary system at different stages of heat treatment and the concomitant variation in hardness are shown to arise from nanoscale fluctuations in the as-deposited boron content from 4 to 8 wt%. High temperature annealing reveals continuous crystallization up to 430 degrees C, overlapping with the domain of B loss due to diffusion into the substrate. The implications of such a microstructure for optimal heat treatment procedures are discussed. (C) 2011 Elsevier B.V. All rights reserved.