نتایج جستجو برای: mineral concentration
تعداد نتایج: 442679 فیلتر نتایج به سال:
As men age, their serum testosterone concentrations decrease, as do their bone densities. Because bone density is also low in hypogonadal men, we hypothesized that increasing the serum testosterone concentrations of men over 65 yr to those found in young men would increase their bone densities. We randomized 108 men over 65 yr of age to wear either a testosterone patch or a placebo patch double...
Abstract Increasing demand for nonfuel mineral commodities has increased concerns regarding the reliability of their supplies. “Criticality” assessments over past decade have attempted to capture this concern through a set indicators, most common which quantifies risk associated with market concentration by applying Herfindahl–Hirschman Index (HHI) world production given commodity country in ye...
Anthropogenic emissions completely overwhelmed natural marine lead (Pb) sources during the past century, predominantly due to leaded petrol usage. Here, based on Pb isotope measurements, we reassess the importance of natural and anthropogenic Pb sources to the tropical North Atlantic following the nearly complete global cessation of leaded petrol use. Significant proportions of up to 30-50% of ...
Mineral loss from bone can be measured accurately and reproducibly by neutron activation of the hand bones using a 5-min irradiation (10(6) n/cm2-sec) with two 200-microgram sources of Cf-252. The hand dose is 7.5 rad equivalent and the dose to the rest of body is 1.5 mrem. Controls (132) and osteoporotic patients (45) were compared. Between ages 20 and 60 the control group showed a bone calciu...
This report summarizes the evidence that the control of the concentration of free calcium ions in body fluids is centered at mineralized bone surfaces. This process involves an increase in the solubility of bone mineral produced by the non-collagenous proteins existing in the bone extracellular fluid (ECF) and on the adjacent surfaces of bone. The result is a basic equilibrium level produced in...
From preliminary studies of the feeding value for mediumwool Merino wethers of various samples of sorghum silage, the following points emerge : 1. Mature silage, in addition to being moderately unpalatable, had a low level of digestible protein, a variable digestible crude fibre and a high mineral content. In spite of the latter, most sheep had negative mineral balances. A feature of the ash co...
Mineral hydrocarbons consist of two fractions, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). MOAH is a potential public health hazard because it may include carcinogenic polycyclic compounds. In the present study, 400 MHz nuclear magnetic resonance (NMR) spectroscopy was introduced, in the context of official controls, to measure MOSH and MOAH in raw ma...
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