No association was observed in any of the studied COX-2 polymorphisms with CP in North India. But, the study should be replicated in larger sample size to arrive at a definitive conclusion. Meta-analysis suggested a role of rs5275 COX-2 polymorphisms in susceptibility to overall CP, and on ethnic basis, rs20417 showed reduced risk of CP in Chinese population.

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Trace mineral zinc is present in our saliva and helps us ght bacteria as well as plaque that is responsible for dental caries and gum disease. Zinc in dentifrices has the potential for hampering the acid production by Streptococcus mutans by up to 50% whereas when used along with uoride, it proved to be bactericidal. Zinc can combat against Fusobacterium nucleatum and Prevotella intermedia, which are causative pathogens of gingivitis. Role of zinc in periodontitis is mainly related to its inuence on oral mucosa, bone metabolism and host response. Zinc deciency affects the functioning of immune cells and also increases the secretion of cytokines causing increased production of free radicals. Zinc deciency results in signicant reduction in collagen synthesis and reduced alkaline phosphatase activity. There is an inverse relationship between serum zinc levels and marginal alveolar bone loss. Therefore, its optimum levels are a prerequisite to maintain periodontal health.

Grade 91 ferritic steel (also known as P91) is widely used for constructing steam generators in prototype fast breeder reactors (PFBR) because of their stress corrosion cracking resistance, high thermal conductivity and low thermal expansion co-efficient for intermediate heat exchangers and austenitic stainless steels (SS304L, SS316L and SS316LN.) Due to their high temperature creep strength and good corrosion resistance, the dissimilar metal weld (DMW) joints between these materials are unavoidable. Inconel 82/182 filler metal is recommended to join these materials since its thermal expansion co-efficient lies between that of ferritic steel and stainless steel. In the present investigation, the tensile properties of each region of DMW joint have been evaluated. DMW joint between P91 and SS 316LN were fabricated using manual metal arc welding (MMAW) process with inconel 82/182 filler metals. The tensile properties of various regions of DMW were examined at a nominal strain rate of 1×10-3 s-1. Microstructural features of various regions of DMW were examined through optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Out of different regions, P91 parent metal exhibited higher tensile strength while the transverse tensile specimens failed at the outer edge of the HAZ of P91 steel. This heterogeneity in mechanical properties may be due to the evolution of complex microstructures developed during welding.