ABSTRACT
<p><b>OBJECTIVE</b>To study the relationship between ultrasonic bone mineral density (BMD) of calcaneus and age, height, and body weight, and to establish the normal reference value for stiffness index (SI) of healthy subjects in Guangxi autonomous region and provide scientific foundation for the diagnosis and prevention of osteoporosis.</p><p><b>METHODS</b>SI of calcaneus in 1 816 healthy adults aged 11-90 years (775 men, 1 041 women) were measured with quantitative ultrasound. According to their ages, all the men and women were divided into 13 groups by 5-year age group.</p><p><b>RESULTS</b>SI reached peak values in 21-25 year group in men (range: 111.45 +/- 21.19) and in 16-20 year group in women (range: 101.26 +/- 17.51). Then the SI value began to decline with aging. The SI featured by a typical dual-peak curve in women and the decrease rate of SI was faster in women than in men over 61 years. Multivariate linear regression analysis showed significantly negative correlation between SI and age (P < 0.001), positive correlation between SI and body weight (P < 0.05 for men; P < 0.01 for women), and positive correlation between SI and height in women (P < 0.01).</p><p><b>CONCLUSION</b>SI correlates with age, height, and weight. The acquired SI value may provide a reference for the diagnosis of osteoporosis.</p>
Subject(s)
Adolescent , Adult , Aged , Aged, 80 and over , Child , Female , Humans , Male , Middle Aged , Bone Density , Calcaneus , Diagnostic Imaging , China , Epidemiology , Osteoporosis , Diagnosis , Epidemiology , UltrasonographyABSTRACT
Optically active form of alpha-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 degrees C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.