912 resultados para Minerals in the body.
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OBJECTIVE To monitor the seasonal body composition alterations in 18 lightweight rowers (six females, 12 males) across a rowing season incorporating preseason, early competition, competition, and postseason. METHODS Subject age was 23.1 (SD 4.5) years, height 170.8 (5.6) cm (female, 23.5 (3.5) years, 180.5 (2.7) cm (male). Body weight, fat mass, and fat-free mass (FFM) were assessed using dual energy x ray absorptiometry (DXA-L Lunar) and skinfold techniques. Weight control techniques were documented before major regattas by a questionnaire. RESULTS Female body weight was reduced from 61.3 (2.9) to 57.0 (1.1) kg (5.9%), while male body weight was reduced from 75.6 (3.1) to 69.8 (1.6) kg (7.8%) preseason to competition season respectively. These body weight reductions were mirrored by a significant reduction in fat mass as indicated by the sum of skinfolds [female seven sites: 80.9 (8.1) to 68.2 (11.8) mm; male eight sites: 54.2 (8.7) to 41.8 (4.8) mm], percentage body fat [female 22.1 (1.0) to 19.7 (2.4)%; male 10.0 (0.9) to 7.8 (0.8)%], and total fat [female 12.5 (5.2) to 10.9 (1.4) kg; male 7.3 (1.9) to 5.6 (1.8) kg] (DXA). In contrast, no changes were observed in FFM despite a season of intensive rowing training. Seasonal body weight control was achieved through reduced total energy and dietary fat intakes. Acute body weight reductions were achieved by exercise in 73.3% of participants, food restriction in 71.4%, and fluid restrictions in 62.9%. CONCLUSIONS Seasonal body weight alterations in lightweight rowers are in response to a significant reduction in fat mass. However, the weight restrictions appear to be limiting an increase in FFM which could be beneficial to rowing performance.
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This paper explores the relationship between the physical strenuousness of work and the body mass index in Finland, using individual microdata over the period 1972-2002. The data contain self-reported information about the physical strenuousness of a respondent’s current occupation. Our estimates show that the changes in the physical strenuousness of work can explain around 8% at most of the definite increase in BMI observed over the period. The main reason for this appears to be that the quantitative magnitude of the effect of the physical strenuousness of work on BMI is rather moderate. Hence, according to the point estimates, BMI is only around 1.5% lower when one’s current occupation is physically very demanding and involves lifting and carrying heavy objects compared with sedentary job (reference group of the estimations), other things being equal. Accordingly, the changes in eating habits and the amount of physical activity during leisure time must be the most important contributors to the upward trend in BMI in industrialised countries, but not the changes in the labour market structure.
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Authors perform zeta potential studies on hematite, corundum, and quartz samples using starches to understand the adsorption behavior of polymeric starch flocculants at the oxide mineral-solution interface and to correlate this information with their flocculation characteristics and investigate effects of pH and CaCl#72 on zeta potential of Fe ore minerals.
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Calculated phase relations in the system MnOSi02-C02-02 were used to propose a thermodynamic explanation for the thermal metamorphism of rhodochrosite beds lying between chert strata. The metamorphic MnOS i 0 2 minerals are arranged in order quartz(chert), rhodonite. tephroite and manganosite-hausmannite-pyrochroite rhodonite across the ore bed. The calculation covered temperatures up to 1000 K and pressures up to 5 kb. The zoning was interpreted as the result of a continuous rise in metamorphic temperature. The equilibrium partner of rhodochrosite changed from rhodonite through manganosite. Across the ore bed there are gradients in the chemical potential of MnO and SiO2 but fugacities of volatlle components such as C02. 02 and H20 were probably uniform at any given time and location during formation of the zones. Assuming that the total pressure and the fugacity of C02 were at 1.4 kb and 1.0 1 b. respectively. rhodonite. tephroite and manganosite would have formed at 472. 478 and 629 K.
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Salmonella enterica causes a range of life-threatening diseases in humans and animals worldwide. Current treatments for S. enterica infections are not sufficiently effective, and there is a need to develop new vaccines and therapeutics. An understanding of how S. enterica spreads in tissues has very important implications for targeting bacteria with vaccine-induced immune responses and antimicrobial drugs. Development of new control strategies would benefit from a more sophisticated evaluation of bacterial location, spatiotemporal patterns of spread and distribution in the tissues, and sites of microbial persistence. We review here recent studies of S. enterica serovar Typhimurium (S. Typhimurium) infections in mice, an established model of systemic typhoid fever in humans, which suggest that continuous bacterial spread to new infection foci and host phagocytes is an essential trait in the virulence of S. enterica during systemic infections. We further highlight how infections within host tissues are truly heterogeneous processes despite the fact that they are caused by the expansion of a genetically homogeneous microbial population. We conclude by discussing how understanding the within-host quantitative, spatial and temporal dynamics of S. enterica infections might aid the development of novel targeted preventative measures and drug regimens.
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Clay mineral assemblages, crystallinity, chemistry, and micromorphology of clay particles in sediments from ODP Site 1146 in the northern South China Sea (SCS) were analyzed, and used to trace sediment sources and obtain proxy records of the past changes in the East Asian monsoon climate since the Miocene, based on a multi-approach, including X-ray diffraction (XRD) and scanning electron microscopy combined with energy dispersive X-ray spectrometry (SEM-EDS). Clay minerals consist mainly of illite and smectite, with associated chlorite and kaolinite. The illite at ODP Site 1146 has very well-to-well crystallinity, and smectite has moderate-to-poor crystallinity. In SEM the smectite particles at ODP Site 1146 often appear cauliflower-like, a typical micromorphology of volcanic smecites. The smectite at ODP Site 1146 is relatively rich in Si element, but poor in Fe, very similar to the smectite from the West Philippine Sea. In contrast, the chemical composition of illite at ODP Site 1146 has no obvious differences from those of the Loess plateau, Yellow River, Yangtze River, and Pearl River. A further study on sediment source indicates that smectite originates mainly from Luzon, kaolinite from the Pearl River, and illite and chlorite from the Pearl River, Taiwan and/or the Yangtze River. The clay mineral assemblages at ODP Site 1146 were not only controlled by continental eathering regimes surrounding the SCS, but also by the changing strength of the transport processes. The ratios of (illite+chlorite)/smectite at ODP Site 1146 were adopted as proxies for the East Asian monsoon evolution. Relatively higher ratios reflect strongly intensified winter monsoon relative to summer monsoon, in contrast, lower ratios indicate a strengthened summer monsoon relative to winter monsoon. The consistent variation of this clay proxy from those of Loess plateau, eolian deposition in the North Pacific, planktonic, benthic foraminifera, and black carbon in the SCS since 20 Ma shows that three profound shifts of the East Asian winter monsoon intensity, and aridity in the Asian inland and the intensity of winter monsoon relative to summer monsoon, occurred at about 15 Ma, 8 Ma, and the younger at about 3 Ma. The phased uplift of the Himalaya-Tibetan plateau may have played a significant role in strengthening the Asian monsoon at 15 Ma, 8 Ma, and 3 Ma.
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Arsenic is accumulated by free-living small mammals, but there is little information on the resultant concentrations in different tissues other than liver and kidney. Such information is important because the severity of toxicological effects may be related to the amount of arsenic accumulated in specific organs, and the availability of arsenic to predators is, in part, dependent on which tissues accumulate arsenic. The objective of this study was to quantify the arsenic concentrations and the percentage of the total body burden (%TBB) accumulated in different body tissues of free-living small mammals and to determine how these factors varied with severity of habitat contamination. Arsenic concentrations were measured in various tissues of wood mice (Apodemus sylvaticus) and bank voles (Clethrionomys glareolus) from a range of arsenic-contaminated sites in southwest Britain. Arsenic concentrations in the gastrointestinal (GI) tract (including contents), liver, kidneys, spleen, lung, femur, and fur of both species varied significantly between sites and were higher in mice and voles from heavily contaminated areas. Heart and brain arsenic concentrations did not vary with degree of environmental contamination. The GI tract and excised carcass contained roughly equal amounts of arsenic and, in sum, comprised 75-85% of the TBB on uncontaminated sites and 90-99% on contaminated sites. Although the excised carcass contains about half of the TBB, its importance in food-chain transfer of arsenic to predators may depend on the bioavailability of arsenic sequestered in fur. In contrast, the GI tract and its contents, provided that it is consumed, will always be a major transfer pathway for arsenic to predators, regardless of the severity of habitat contamination.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Objective: To review the literature on the role of calcium, phosphorus and trace elements in the nutrition of extremely low birth weight infants, considering their importance for metabolism, bone mineralization and as dietary components. Sources of data: MEDLINE, the Cochrane Database of Systematic Reviews and books on nutrition were searched between 1994 and 2004. Original research studies and reviews were selected. Summary of the findings: Extremely preterm infants are frequently growth-restricted at hospital discharge as a consequence of difficulties in the provision of adequate nutrition. The long-term effects of this growth restriction need to be determined. There is a paucity of studies about the role of minerals, especially micronutrients, in the nutrition of extremely preterm infants. The principal focus of this review was on calcium and phosphorus metabolism, bone mineralization and parenteral and enteral supplementation. A critical evaluation of post-discharge nutrition and its influence upon growth and bone mineralization was presented. Selenium and zinc requirements and the role of selenium as an antioxidant with possible effects on free radical diseases of the preterm infant were discussed. Conclusions: Extremely preterm infants have low mineral reserves and, as a consequence, may have deficiencies in the postnatal period if they do not receive parenteral or enteral supplementation. More studies are needed to elucidate the actual requirements and the appropriate supplementation of micronutrients. There are controversies about the outcome and the influence of post-discharge nutrition on bone disease of prematurity. Copyright © 2005 by Sociedade Brasileira de Pediatria.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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In der vorliegenden Studie wurden verschiedene Techniken eingesetzt um drei Proben (4, 7, and 8) die aus denrnKorrosionsprodukten von aus dem Kosovo Krieg stammenden Munitionskugeln, bestehend aus abgereichertem Uranrn(Depleted Uranium - DU), zu untersuchen. Als erstes Verfahren wurde die Raman-Spektroskopie eingesetzt. Hierbeirnzeigte sichin den Proben, charakterisiert durch einen Doppelpeak, die Anwesenheit von Schoepitrn(UO2)8O2(OH)12(H2O)12. Der erste und zweite Peakzeigte sich im Spektralbereich von 840,3-842,5 cm-1rnbeziehungsweise 853,6-855,8 cm-1. Diese Werte stimmen mit den Literaturwerten für Raman-Peaks für Schoepitrnüberein. Des Weiteren wurde bei dieser Untersuchungsmethode Becquerelite Ca(UO2)6O4(OH)6(H2O)8 mit einemrnPeak im Bereich zwischen 829 to 836 cm-1 gefunden. Aufgrund des Fehlens des Becquerelitespektrums in derrnSpektralbibliothek wurde eine in der Natur vorkommende Variante analysiert und deren Peak bei 829 cm-1 bestimmt,rnwas mit den Ergebnissen in den Proben korrespondiert. Mittels Röntgenbeugung (X-Ray Diffraction, XRD) zeigtenrnsich in allen Proben ähnliche Spektren. Das lässt darauf schließen, dass das pulverisierte Material in allen Probenrndas gleiche ist. Hierbei zeigte sich eine sehr gute Übereinstimmung mit Schoepit und/oder meta-rnSchoepit(UO2)8O2(OH)12(H2O)10, sowie Becquerelite. Weiterhin war weder Autunit, Sabugalit noch Uranylphosphatrnanwesend, was die Ergebnisse einer anderen Studie, durchgeführt an denselben Proben, wiederlegt. DiernAnwesenheit von P, C oder Ca im Probenmaterial konnte ausgeschlossen werden. Im Falle von Calciumkann diesrnmit der Anwesenheit von Uran erklärt werden, welches aufgrund seines Atomradius bevorzugt in Becquerelite (1:6)rneingebaut wird. Die beiden Hauptpeaks für Uran lagen im Falle von U 4f 7/2 bei 382.0 eV und im Falle von U 4f 5/2rnbei 392 eV. Diese Werte mit den Literaturwerten für Schoepit und meta-Schoepitüberein. Die Ergebnissernelektronenmikroskopischen Untersuchung zeigen U, O, Ca, Ti als dominante Komponenten in allen Messungen.rnElemente wie Si, Al, Fe, S, Na, und C wurden ebenfalls detektiert; allerdings kann nicht ausgeschlossen werden,rndass diese Elemente aus dem Boden in der unmittelbaren Umgebung der Munitionsgeschosse stammen. Gold wurdernebenfalls gemessen, was aber auf die Goldarmierung in den Probenaufbereitungsbehältern zurückgeführt werdenrnkann. Die Elektronenmikroskopie zeigte außerdem einige Stellen in denen elementares Uran und Bodenmineralernsowie sekundäre Uranminerale auftraten. Die Elementübersicht zeigt einen direkten Zusammenhang zwischen U andrnCa und gleichzeitig keine Korrelation zwischen U und Si, oder Mg. Auf der anderen Seite zeigte sich aber einrnZusammenhang zwischen Si und Al da beide Konstituenten von Bodenmineralen darstellen. Eine mit Hilfe derrnElektronenstrahlmikroanalyse durchgeführte quantitative Analyse zeigte den Massenanteil von Uran bei ca. 78 - 80%,rnwas mit den 78,2% and 79,47% für Becquerelite beziehungsweise Schoepit aufgrund ihrer Summenformelrnkorrespondiert. Zusätzlich zeigt sich für Calcium ein Massenanteil von 2% was mit dem Wert in Becquerelite (2.19%)rnrecht gut übereinstimmt. Der Massenanteil von Ti lag in einigen Fällen bei 0,77%, was auf eine noch nicht korrodierternDU-Legierung zurückzuführen ist. Ein Lösungsexperiment wurde weiterhin durchgeführt, wobei eine 0,01 M NaClO4-rnLösung zum Einsatz kam in der die verbliebene Probensubstanz der Korrosionsprodukte gelöst wurde;rnNatriumperchlorate wurde hierbei genutzt um die Ionenstärke bei 0,01 zu halten. Um Verunreinigungen durchrnatmosphärisches CO2 zu vermeiden wurden die im Versuch für die drei Hauptproben genutzten 15 Probenbehälterrnmit Stickstoffgas gespült. Eine Modelkalkulation für den beschriebenen Versuchsaufbau wurde mit Visual MINTEQrnv.3.0 für die mittels vorgenannten Analysemethoden beschriebenen Mineralphasen im pH-Bereich von 6 – 10 imrnFalle von Becquerelite, und Schoepit berechnet. Die modellierten Lösungskurven wurden unter An- und Abwesenheitrnvon atmosphärischem CO2 kalkuliert. Nach dem Ende des Lösungsexperiments (Dauer ca. 6 Monate) zeigten diernKonzentrationen des gelösten Urans, gemessen mittels ICP-OES, gute Übereinstimmung mit den modelliertenrnSchoepit und Becquerelite Kurven. Auf Grund des ähnlichen Löslichkeitverhaltens war es nicht möglich zwichen denrnbeiden Mineralen zu unterscheiden. Schoepit kontrolliert im sauren Bereich die Löslichkeit des Urans, währendrnbecquerelit im basichen am wenigsten gelöst wird. Des Weiteren bleibt festzuhalten, dass ein Anteil an CO2 in diernverschlossenen Probenbehälter eingedrungen ist, was sich mit der Vorhersage der Modeldaten deckt. Die Löslichkeitrnvon Uran in der Lösung als Funktion des pH-Wertes zeigte die niedrigsten Konzentrationen im Falle einer Zunahmerndes pH-Wertes von 5 auf 7 (ungefähr 5,1 x 10-6 mol/l) und einer Zunahme des pH-Wertes auf 8 (ungefähr 1,5 x 10-6rnmol/l bei). Oberhalb dieses Bereichs resultiert jeder weitere Anstieg des pH-Wertes in einer Zunahme gelösten Uransrnin der Lösung. Der ph-Wert der Lösung wie auch deren pCO2-Wert kontrollieren hier die Menge des gelösten Urans.rnAuf der anderen Seite zeigten im Falle von Becquerelite die Ca-Konzentrationen höhere Werte als erwartet, wobeirnwahrscheinlich auf eine Vermischung der Proben mit Bodensubstanz zurückgeführt werden kann. Abschließendrnwurde, unter Berücksichtigung der oben genannten Ergebnisse, eine Fallstudie aus Basrah (Irak) diskutiert, wo inrnzwei militärischen Konflikten Uranmunition in zwei Regionen unter verschiedenen Umweltbedingungen eingesetztrnwurden.