Association of human leukocyte antigen DRB1 polymorphism and tuberculosis: a meta-analysis.

OBJECTIVE: To determine whether the human leukocyte antigen DRB1 (HLA-DRB1) is associated with clinical tuberculosis (TB). METHODS: Pooled odds ratios (OR) with 95% confidence intervals (CIs) were used to evaluate the strength of the association between HLA-DRB1 alleles and risk of TB. The χ(2)-based Q-test and I(2) statistics were calculated to examine heterogeneity. Egger's test was performed for the assessment of publication bias. Subgroup analysis was performed based on ethnicity and genotyping methods. RESULTS: A total of 19 case-control studies with 16 alleles (HLA-DRB1*01-HLA-DRB1*16) were included in this meta-analysis. No significant publication bias was detected among these studies. The HLA-DRB1*03 (OR 0.77, 95%CI 0.64-0.93, P = 0.0057) showed a protective effect, while HLA-DRB1*04 (OR 1.24, 95%CI 1.00-1.55, P = 0.0494), HLA-DRB1*08 (OR 1.45, 95%CI 1.14-1.86, P = 0.0030) and HLA-DRB1*16 (OR 1.39, 95%CI 1.04-1.87, P = 0.0269) were significantly associated with increased TB occurrence. Subgroup analysis showed that both ethnicity and genotyping method affected the association between HLA-DRB1*03, HLA-DRB1*04 and HLA-DRB1*08 alleles and TB occurrence. CONCLUSION: These results reinforce the importance of HLA-DRB1 alleles in the development of infectious diseases.

Oxidation pattern of small silicon oxide clusters: structures and stability of Si6On (n = 1-12).

We have performed systematic ab initio calculations to study the structures and stability of Si(6)O(n)() clusters (n = 1-12) in order to understand the oxidation process in silicon systems. Our calculation results show that oxidation pattern of the small silicon cluster, with continuous addition of O atoms, extends from one side to the entire Si cluster. Si atoms are found to be separated from the pure Si cluster one-by-one by insertion of oxygen into the Si-O bonds. From fragmentation energy analyses, it is found that the Si-rich clusters usually dissociate into a smaller pure Si clusters (Si(5), Si(4), Si(3), or Si(2)), plus oxide fragments such as SiO, Si(2)O(2), Si(3)O(3), Si(3)O(4), and Si(4)O(5). We have also studied the structures of the ionic Si(6)O(n)(+/-) (n = 1-12) clusters and found that most of ionic clusters have different lowest-energy structures in comparison with the neutral clusters. Our calculation results suggest that transformation Si(6)O(n)+(a) + O --> Si(6)O(n+1)+(a) should be easier.