Concordane of OSTA and lumbar spine BMD by DXA in identifying risk of osteoporosis

OBJECTIVE: To investigate the accuracy of Osteoporosis Self-assessment Tool for Asians (OSTA) in identifying the risk of osteoporosis in postmenopausal women. To validate use of OSTA risk index by comparing it with the bone mineral density (BMD) of lumbar spine measured by dual energy X-ray absorptiometry (DXA). METHODS: The data of lumbar spine BMD (LS BMD) measurements by DXA of 218 postmenopausal women of Han nationality in Sichuan province were compared with OSTA risk index. The concordance of OSTA and LS BMD were calculated and analyzed by fourfold table and receiver operating characteristic (ROC) curve. RESULTS: The prevalence of osteoporosis in these women was 40.4% and 61.5%, with the LS BMD T score cutoffs -2.5 and -2.0, respectively. The sensitivity, specificity, and accuracy of OSTA risk index compared with T score cutoff -2.5 of LS BMD were 59.1%, 56.9% and 57.8%, respectively, while they were 57.5%, 63.1%, 59.6% by T score cutoff -2.0. CONCLUSION: For identifying risk of osteoporosis, the concurrence was lower than those reported studies when comparing LS BMD measurements to OSTA risk index in Chinese Han nationality postmenopausal women of Sichuan province. Physicians should identify women who need BMD measurement according to more factors rather than age and body weight

The effects of facet-dependent palladium-titania interactions on the activity of Pd/Rutile catalysts for lean methane oxidation

Rod-shaped rutile materials with different proportions of (110) and (111) facets exposed were hydrothermally prepared, and the facet-dependent effects of rutile on the activity of supported palladium phases in lean methane oxidation were elucidated. Although a stronger interaction between palladium and the rutile (111) facet was confirmed by systematic characterizations, performance evaluation and in situ DRIFTS revealed deteriorated catalytic efficiencies of palladium catalysts. Specifically, while complete methane oxidation was achieved at temperature below 450 ◦C over a Pd/Rutile-(110) catalyst, only 39% of methane were eliminated at 500 ◦C over its counterpart supported on Rutile-(111). Investigations on rutile supported palladium catalysts further revealed that the facet-dependent palladium-titania interactions profoundly affected the particle sizes and chemical states of the deposited palladium species. In combination with DFT calculations, it was then found that Pd4+ species that might function synergistically with Pd2+ in methane activation were not as stable on the rutile (111) facet, due to the strong electron transfer from this substrate. It is hoped that the conclusions drawn in this work would provide supplementary understanding of the facet-dependent metal-TiO2 interactions and some inspirations on the further rutile-related catalyst design