background: migarine is the most common headache around the world including iran. in recent years, vitamin d deficiency has been shown to a global health problem. a few studies have been determined inverse association between serum levels of vitamin d with a headache. so, in this study, we investigated the effect of vitamin d supplementation on symptoms and c-reactive protein(crp) among patient...

Maintenance management has a direct influence on equipment reliability and safety. However, a large portion of traditional maintenance models and reliability analysis methods usually assumes that only perfect maintenance is performed on the system and the system will restore to as good as new regardless of the kind of preventive maintenance work-order that is performed. This is not practical in...

background: although the precise etiology of multiple sclerosis (ms) is unknown, it seems that both genetic and environmental factors are important. recent studies suggest that low serum vitamin d levels are important environmental factor in ms. the aim of this study was to compare the serum levels of vitamin d between ms patients and healthy subjects, and to determine its association with disa...

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in more recent years, it has become increasingly recognized that r&d; (research and development) is a key driver of economic growth, a source of innovation and change, and as such stimulates improvements in productivity and economic competitiveness. it is closely associated with knowledge and flexibility, two factors that have gained new significance as a source of competitiveness in an increas...

Background: Several studies investigated the association of ACE I/D polymorphism with the risk and severity of COVID-19 infection.  However, the information in each of the published studies is limited, and the results were inconsistent or even contradictory. Accordingly, this meta-analysis evaluated the association between the ACE I/D polymorphism and COVID-19 susceptibility and severity. Metho...