Efficacy of intravenous zoledronic acid in the prevention and treatment of osteoporosis:A meta-analysis

Objective:To compare the eflect of zoledronic acid in treatment and prevention of osteoporosis with placebo.Methods:Random control trials regarding zoleilroiiic acid in treatment of osteoporosis were retrieved by selecting Medline.EMbase and Pubmed databases till April 2012. The RevMan software was used for all of the statistical analysis.Results:A total of 9 trials were included in this meta-analysis.The pooled effect shewed that zoledronic acid could increase the bone mineral density by 2.98 times compared with placebo,and reduce the rate of fracture in patients by 32%.The results should the zoledronic acid intervention had significantly less serious adverse events than controls,and the odds ratio was 0.81(0.76-0.87).The longer term intervention, more than 12 months intervention,could gain a better prevention effect for osteoporosis(OR,95% CI for RMD was 3.35.2.77-3.92:for fracture was 0.67.0.54-0.82).Conclusions:This present study shows that zoledronic acid could be effective approach in the prevention of osteoporosis,and could increase the bone mineral density and reduce the risk ol facture.

Mitigation effects on the reflected overpressure of blast shock with water surrounding an explosive in a confined space

The mitigation of blast shock with water has broad application prospects. Understanding the mitigation effects on the reflected overpressure of the explosion shock with water surrounding an explosive in a confined space is of great significance for military explosives safety applications. To estimate the effects of the parameters on the reflected overpressure of blasted shock wave, a series of experiments were carried out in confined containers with spherical explosives immersed in a certain thickness of water,and numerical simulations were conducted to explore the corresponding mechanisms. The results reveal that the reflected overpressure is abnormally aggravated at a small scaled distance. This aggravation is due to the high impulse of the bulk accelerated water shell converted from the explosion. With increasing scaled distance, the energy will be gradually dissipated. The mitigation effects will appear with the dispersed water phase front impacting at a larger scaled distance, except in the case of a dense water phase state. A critical scaled distance range of 0.7-0.8 m/kg^(1/3) for effective mitigation was found. It is suggested that the scaled distance of space walls should be larger than the critical value for a certain water-to-explosive weight ratio range(5-20).

Analysis on spectral gain characteristics of PPMgLN based quasi-phase-matching optical parametric amplification

A deep understanding of the spectral gain characteristics of optical parametric oscillators (OPOs) and optical parametric amplifiers (OPAs) is important for a highly efficient optical parametric conversion. We numerically calculated the spectral gain characteristics of a quasi-phase-matching (QPM) parametric conversion process using the periodically poled 6% (mol/mol) MgO doped LiNbO3 (PPMgLN) as the nonlinear crystal. In the simulation we utilized the approach of a transformative matrix of the periodically poled nonlinear medium, which results from the small-signal approximation of three-wave mixed nonlinear equations. Numerical simulation results show that: (1) The full width at half maximum (FWHM) of the spectral gain of the parametric process becomes wider with the increase of parametric wavelength and reaches the maximum at degeneration; (2) The gain coefficient decreases gradually with the increase of parametric wavelength; (3) The spectral gain bandwidth decreases correspondingly with the increase of the nonlinear material length; (4) There exists an optimal parametric wavelength band, which is most suitable for the high gain parametric conversion when pumped by a laser source with a wide wavelength band, such as the high power fiber laser.