Search results for " mineral"
showing 10 items of 541 documents
Vitamin D status as a determinant of peak bone mass in young Finnish men.
2004
Severe vitamin D deficiency causes rickets, but scarce data are available about the extent to which vitamin D status determines the development of the peak bone mass in young adults. Our aim was to evaluate the prevalence of vitamin D deficiency [serum 25-hydroxyvitamin D (25-OHD) less than the lower limit of the reference range of 20–105 nmol/liter] and the relationship between vitamin D status and peak bone mass among young Finnish men. A cross-sectional study of determinants of peak bone mass with data on lifestyle factors collected retrospectively was performed in 220 young men, aged 18.3–20.6 yr. One hundred and seventy men were recruits of the Finnish Army, and 50 were men of similar …
Physical Activity and Exercise in the Maintenance of the Adult Skeleton and the Prevention of Osteoporotic Fractures
2013
Abstract Physical activity and exercise are promoted as a nonpharmacological strategy to maintain or enhance musculoskeletal health in adults and prevent osteoporotic fracture. Less clear is the optimal mode, intensity, duration, and frequency of activity to achieve this objective. Although a substantial osteogenic response to appropriate mechanical loading is clearly evident in animal models and strongly supported from athlete cross-sectional and prospective studies, the results from exercise interventions in adults are less impressive with modest net benefits generally of 1% to 3% in bone mineral density (BMD) (g/cm2) at the clinically relevant hip and spine following prolonged weight-bea…
Bone mineral metabolism in the micropremie
2000
Environmental factors, nutritional supplies, hormonal status, diseases, and treatments appear to affect postnatal skeletal growth and mineralization in VLBW infants. Compared with their term counterparts, ELBW infants are at risk of postnatal growth deficiency and osteopenia at the time of hospital discharge. From recent data, DXA is becoming one of the reference techniques to evaluate mineral status, whole-body composition, and effects of dietary manipulations on weight gain composition and mineral accretion in preterm infants. Weight gain and length increases need to be evaluated carefully during the first weeks of life, in the intensive care unit and out of it, in the step down unit. Nut…
Low volumetric BMD is linked to upper-limb fracture in pubertal girls and persists into adulthood: A seven-year cohort study
2009
Abstract The aetiology of increased incidence of fracture during puberty is unclear. This study aimed to determine whether low volumetric bone mineral density (vBMD) in the distal radius is associated with upper-limb fractures in growing girls, and whether any such vBMD deficit persists into adulthood. Fracture history from birth to 20 years was obtained and verified by medical records in 1034 Finnish girls aged 10–13 years. Bone density and geometry at distal radius, biomarkers and lifestyle/behavioural factors were assessed in a subset of 396 girls with a 7.5-year follow-up. We found that fracture incidence peaked during puberty (relative risk 3.1 at age of 8–14 years compared to outside …
Chemical weathering of volcanic rocks at the island of Pantelleria, Italy: Information from soil profile and soil solution investigations
2007
Abstract Concentrations of major, minor and trace elements were determined in soil profiles and soil solutions from the island of Pantelleria, Sicily Channel, to evaluate the weathering extent of soils evolved on trachytic and pantelleritic rocks and the aqueous transport of elements by their soil solutions. The chemical index of alteration (CIA) indicates a low-to-moderate degree of weathering; consistently, the mineralogical and geochemical imprints of the parent rocks are generally preserved. The chemical weathering appears to be incongruent, owing to primary minerals and glass dissolving to a variable degree while secondary minerals have formed. Based on the calculated saturation state …
Over-estimation of efficiency of weathering in tropical “Red Soils”: its importance for geoecological problems
2000
Abstract Weathering and soil formation rates are regarded as the main criteria of a tolerable soil loss. The efficiency of weathering in the seasonal semiarid tropics has often been greatly over-estimated especially in the geomorphologic literature in which weathering is assumed to be as fast or even faster than surface erosion. Six selected “Red Soils” in two intramontane basins of hyperthermic SW Nepal near the border with India, with 1500–1750 mm annual rainfall (5 humid months), and a “Black Soil” near Baroda, Gujarat, India (3–4 humid months) were studied mineralogically. Two of the “Red Soils” have TL ages between 10 and 30 ka, the “Black Soil” has one of about 10 ka. The yellowish si…
Clay minerals, oxyhydroxide formation, element leaching and humus development in volcanic soils
2008
Aweathering sequence with soils developing on volcanic, trachy-basaltic parent materials with ages ranging from 100–115,000 years in the Etna region served as the basis to analyse and calculate the accumulation and stabilisation mechanisms of soil organic matter (SOM), the transformation of pedogenic Fe and Al, the formation and transformation of clay minerals, the weathering indices and, by means of mass-balance calculations, net losses of the main elements. Although the soils were influenced by ash depositions during their development and the soil on the oldest lava flow developed to a great extent under a different climate, leaching of elements and mineral formation and transformation co…
Dažādu saimniecību graudaugu sastāva izvērtējums
2016
Dažādu saimniecību graudaugu sastāva izvērtējums. Andža K., zinātniskā vadītāja Ķīm.maģ. lektore Balcerbule Z. Bakalaura darbs, 54 lappuses, 21 attēli, 13 tabulas, 39 literatūras avoti, 4 pielikumi. Latviešu valodā. Darbā analizēti graudu paraugi no dažāda veida saimniecībām – intensīvās un bioloģiskās saimniecības. Kviešu, miežu un auzu paraugiem tika noteikti graudu kvalitātes raksturlielumi (proteīni, mitrums, lipeklis, Zeleny indekss, ciete, tilpummasa, krišanas skaitlis). Izmantota sausā mineralizācija graudu pelnu satura noteikšanai. Ar liesmas atomabsorbciometru un elektrotermālo atomabsorbciomeru tika noteikts svina, kadmija, cinka un vara saturs graudu paraugos, veikta iegūto rezul…
Dating of prograde metamorphic events deciphered from episodic zircon growth in rocks of the Dabie–Sulu UHP complex, China
2006
The timing of ultra-high pressure (UHP) metamorphism has been difficult to determine because of a lack of age constraints on crucial events, especially those occurring on the prograde path. New Sensitive High-Resolution Ion Microprobe (SHRIMP) U–Pb age and rare-earth element (REE) data of zircon are presented for UHP metamorphic rocks (eclogite, garnet peridotite, garnet pyroxenite, jadeite quartzite and garnet gneiss) along the Dabie–Sulu UHP complex of China. With multiphase metamorphic textures and index mineral inclusions within zircon, the Dabie data define three episodes of eclogite-facies metamorphism, best estimated at 242.1 ± 0.4 Ma, 227.2 ± 0.8 Ma and 219.8 ± 0.8 Ma. Eclogite-faci…
Experimental models of orthodontic tooth movement and their effects on periodontal tissues remodelling.
2021
Made available in DSpace on 2022-04-29T08:31:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Objectives: The present study aimed to compare two different models of orthodontic tooth movement (OTM) in rats by evaluating tooth movement efficiency and periodontal tissues remodelling. Design: Fifteen animals were randomly distributed into 3 groups: control group (untreated); ligature appliance (LA) as experimental OTM using a closed coil spring fixed around maxillary first molar by steel ligature; occlusal appliance (OA) as experimental OTM using a closed coil spring attached on the occlusal surface of the maxillary f…