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Ca/vitamin D supplementation maintains bone health and decreases stress fracture risk during initial military training (IMT); however, there is evidence that Ca may negatively affect the absorption of other critical micronutrients, particularly Fe. The objective of this randomised, double-blind, placebo-controlled trial was to determine whether providing 2000 mg/d Ca and 25µg/d vitamin D in a fortified food product during 9 weeks of military training affects Fe status in young adults. Male (n 98) and female (n 54) volunteers enrolled in US Army basic combat training (BCT) were randomised to receive a snack bar with Ca/vitamin D (n 75) or placebo (snack bar without Ca/vitamin D; n 77) and were instructed to consume 2 snack bars/d between meals throughout the training course. Circulating ionised Ca was higher (P<0·05) following BCT among those consuming the Ca/vitamin D bars compared with placebo. Fe status declined in both groups over the course of BCT. Transferrin saturation, serum ferritin and Hb were reduced (P<0·05) and soluble transferrin receptor increased (P<0·05) following BCT. There were no differences (P>0·05) in markers of Fe status between placebo and Ca/vitamin D groups. Collectively, these data indicate that Ca/vitamin D supplementation through the use of a fortified food product consumed between meals does not affect Fe status during IMT.
Polarized radiation is used in a Fourier transform infrared (FTIR) microspectroscopic technique to detect molecular conformational change in collagen fibers resulting from deterioration. Absorbance spectra of single fibers are produced with polarization oriented first parallel (A‖) and then perpendicular (A⊥) to the fiber axis. The amide Ill band (1230- 1300 cm−1) shows strong positive dichroism, with up to six times greater absorbance occurring with parallel polarization. Losses of dichroism result from breakdown in the molecular structure of collagen. Integrations of the amide III bands are used in ratios, A‖/A⊥;, which provide a measure of the degree of molecular order. Ratios for degraded and undegraded material are compared to produce semi-quantitative information about deterioration.
Amorphous and microcrystalline germanium films prepared by glowdischarge and molecular beam deposition were hydrogenated after deposition, using a 3cm Kaufman ion source. The hydrogen profiles were determined using the N15p nuclear resonance reaction. We found that the surface region hydrogen concentration depended on ion beam modification of the material, and the bulk concentration was determined by the hydrogenation conditions and deposition conditions. The light and dark conductivities wee measured before and after hydrogenation. Several orders of magnitude change in the ratios of the conductivities were measured under optimum hydrogenation conditions. The aclivation energy for electrical conductivity was measured and found to be dependent on film structure thickness and hydrogenation conditions.
Low electrical contact resistance is essential for the fabrication of high efficiency thermoelectric generators in order to convert heat to electricity. These contacts must be stable to high temperatures and through thermal cycling. A ratio of the contact resistance to the leg resistance below 0.1 is the goal for fabrication of a high efficiency thermoelectric power generation device. Here we present the fabrication procedures and characterization of contacts of metal alloys to Pb-Sb-Ag-Te (LAST) and Pb-Sb-Ag-Sn-Te (LASTT) compounds. Contacts were fabricated and measured for both ingot and hot pressed materials. Stainless steel 316 has shown a low resistance contact to these thermoelectric materials when the proper bonding conditions are used. Different time-temperature-pressure conditions for bonding to n-type and to p-type legs are presented. Contact resistances below 10μΩcm2 have been measured. In addition, break tests have shown bond strengths exceeding the semiconductor fracture strength. One of the considerations used in selecting iron alloys for electrical interconnects is the similarity in the coefficient of thermal expansion to the LAST and LASTT materials which is 18 ppm/°C and relatively temperature insensitive. Contacts to the thermoelectric materials were accomplished by diffusion bonding in a furnace developed in our lab at Michigan State University. The furnace is capable of reaching temperatures of up to 1000°C with a controlled atmosphere of a reducing gas. Fabrication procedures and contact data are presented in this paper.
The background and planned research activities are outlined for a new UK research consortium focused on Decommissioning, Immobilisation And Management Of Nuclear-wastes for Disposal (DIAMOND). This consortium is the first integrated trans-disciplinary and multi-institution academic research network in the UK, focused on nuclear waste management.
Fe is an essential micronutrient required for optimal cognitive and physical performance. Cross-sectional studies indicate that training degrades Fe status in female military personnel; however, longitudinal studies to measure the direct impact of military training on Fe status and performance have not been conducted. As such, the objective of the present study was to determine the longitudinal effects of military training on Fe status in female soldiers. Fe status was assessed in ninety-four female soldiers immediately before and following a 9-week basic combat training (BCT) course. Fe status indicators included Hb, erythrocyte distribution width (RDW), serum ferritin, transferrin saturation and soluble transferrin receptor (sTfR). A 2-mile (3·2 km) run test was performed at the end of BCT to assess aerobic performance. Fe status was affected by BCT, as all Fe status indicators, excluding Hb, were diminished (P ≤ 0·01) at the end of BCT. Fe status indicators at the end of BCT (Hb and RDW) were associated (P ≤ 0·05) with running performance, as was the change in sTfR over the training period (r 0·320; P ≤ 0·05). In conclusion, Fe status in female soldiers is degraded during BCT, and degraded Fe status is associated with diminished aerobic performance. Female athletes and military personnel should strive to maintain Fe status to optimise physical performance.