Diet-induced milk fat depression: Association with changes in milk fatty acid composition and fluidity of milk fat

This experiment was designed to examine changes in milk fatty acids during fish oil-induced milk fat depression (MFD) and to test the theory that these changes are related to milk fat fluidity. The experiment was divided into three periods: 1) Baseline: all cows (n = 12) received a high fiber diet without fish oil (FO) for 12 days; 2) Treatment: 4 cows/group received the following treatments for 21 days: a) Low fiber diet without FO (LF), b) High fiber diet+FO (HF+FO) and c) Low fiber diet+FO (LF+FO); 3) Post-treatment: cows returned to the baseline diet and were monitored for 12 days. FO was included at 1.6% DM and HF and LF diets had 40 and 26% NDF, respectively. Milk fat content and yield were unchanged by the LF diet, but were reduced by FO diets at both dietary fiber levels and recovered in the post-treatment period. FO diets caused a pronounced reduction in stearic and oleic acid concentrations in milk fat and an equally pronounced increase in trans-18:1 fatty acid concentrations. Milk fat mean melting point (MMP) was correlated with MFD (r=0.73) and with milk oleic acid concentration (r=-0.92). The ratio of oleic:stearic in milk fat increased gradually and consistently in response to FO. Trans-C18:1 isomers with double bounds at carbon :<= 10 increased with greater MFD and those with double bonds at carbon ! I I decreased with greater MFD. Trans-9 cis-11 CLA explained more than 80% of MFD and was strongly correlated with trans-10 C18:1. Maintenance of MMP below 39-40 degrees C suggests that the mammary gland was able to secrete only milk fat with adequate fluidity and that MFD could be an adaptation mechanism to prevent secretion of milk with higher MMP. (C) 2007 Elsevier B.V. All rights reserved.

Leaf area index estimation with MODIS reflectance time series and model inversion during full rotations of Eucalyptus plantations

The leaf area index (LAI) of fast-growing Eucalyptus plantations is highly dynamic both seasonally and interannually, and is spatially variable depending on pedo-climatic conditions. LAI is very important in determining the carbon and water balance of a stand, but is difficult to measure during a complete stand rotation and at large scales. Remote-sensing methods allowing the retrieval of LAI time series with accuracy and precision are therefore necessary. Here, we tested two methods for LAI estimation from MODIS 250m resolution red and near-infrared (NIR) reflectance time series. The first method involved the inversion of a coupled model of leaf reflectance and transmittance (PROSPECT4), soil reflectance (SOILSPECT) and canopy radiative transfer (4SAIL2). Model parameters other than the LAI were either fixed to measured constant values, or allowed to vary seasonally and/or with stand age according to trends observed in field measurements. The LAI was assumed to vary throughout the rotation following a series of alternately increasing and decreasing sigmoid curves. The parameters of each sigmoid curve that allowed the best fit of simulated canopy reflectance to MODIS red and NIR reflectance data were obtained by minimization techniques. The second method was based on a linear relationship between the LAI and values of the GEneralized Soil Adjusted Vegetation Index (GESAVI), which was calibrated using destructive LAI measurements made at two seasons, on Eucalyptus stands of different ages and productivity levels. The ability of each approach to reproduce field-measured LAI values was assessed, and uncertainty on results and parameter sensitivities were examined. Both methods offered a good fit between measured and estimated LAI (R(2) = 0.80 and R(2) = 0.62 for model inversion and GESAVI-based methods, respectively), but the GESAVI-based method overestimated the LAI at young ages. (C) 2010 Elsevier Inc. All rights reserved.

MODIS NDVI time-series allow the monitoring of Eucalyptus plantation biomass

The use of remote sensing is necessary for monitoring forest carbon stocks at large scales. Optical remote sensing, although not the most suitable technique for the direct estimation of stand biomass, offers the advantage of providing large temporal and spatial datasets. In particular, information on canopy structure is encompassed in stand reflectance time series. This study focused on the example of Eucalyptus forest plantations, which have recently attracted much attention as a result of their high expansion rate in many tropical countries. Stand scale time-series of Normalized Difference Vegetation Index (NDVI) were obtained from MODIS satellite data after a procedure involving un-mixing and interpolation, on about 15,000 ha of plantations in southern Brazil. The comparison of the planting date of the current rotation (and therefore the age of the stands) estimated from these time series with real values provided by the company showed that the root mean square error was 35.5 days. Age alone explained more than 82% of stand wood volume variability and 87% of stand dominant height variability. Age variables were combined with other variables derived from the NDVI time series and simple bioclimatic data by means of linear (Stepwise) or nonlinear (Random Forest) regressions. The nonlinear regressions gave r-square values of 0.90 for volume and 0.92 for dominant height, and an accuracy of about 25 m(3)/ha for volume (15% of the volume average value) and about 1.6 m for dominant height (8% of the height average value). The improvement including NDVI and bioclimatic data comes from the fact that the cumulative NDVI since planting date integrates the interannual variability of leaf area index (LAI), light interception by the foliage and growth due for example to variations of seasonal water stress. The accuracy of biomass and height predictions was strongly improved by using the NDVI integrated over the two first years after planting, which are critical for stand establishment. These results open perspectives for cost-effective monitoring of biomass at large scales in intensively-managed plantation forests. (C) 2011 Elsevier Inc. All rights reserved.

Composition of phenolic acids content in apple (Malus sp) pomace

The present work aimed the study of phenolic acids composition in apple pomace of Gala and Fuji cultivars. Phenolic acids were fractionated in phenolic acids, esterified and insoluble and analyzed by gas chromatography-mass spectrometry (GC-MS). Sixteen phenolic acids were identified in apple pomace samples. Total phenolic acids in apple pomace from Gala and Fuji cultivars were, in dry weight, 93.94 mg/g and 68.38 mg/g, respectively. Content of free phenolic acids in apple pomace from Gala cultivar was 29.11 mg/g and the following acids were identified: salicylic, protocatequinic, quinic, p-coumaric, gallic, propylgallate and synapic. Content of free phenolic acids in apple pomace from Fuji cultivar was 16.03 mg/g and the following acids were identified: salicylic, protocatequinic, gallic, ferulic and sinapic. Salicylic was the predominant free phenolic acids found in both cultivars, consisting of 91.67% and 63.57% of the free phenolic acids in Gala and Fuji cultivars, respectively. Chlorogenic acid (1.147 mg/g) was found only in apple pomace from Fuji cultivar. Content of esterified phenolic acids in apple pomace from Gala and Fuji cultivars were 53.75 mg/g and 48.29 mg/g, respectively. It was verified that the predominant esterified phenolic acid in pomace from apple Gala is derived from salicylic acid (52.76 mg/g). Acids derived from gallic acid (0.175 mg/g), propylgallate acid (0.198 mg/g), ferulic acid (0.159 mg/g) and sinapic acid (0.140 mg/g) were also found in Gala cultivar. Regarding to pomace from cultivar Fuji, the main esterified phenolic acid found is also derived from salicylic acid (47.42 mg/g) followed by gallic acid (0.270 mg/g), benzoic acid (0.194 mg/g) and sinapic acid (0.115 mg/g). Content of insoluble phenolic acids in apple pomace from Gala and Fugi cultivars were, in dry weight, 11.08 mg/g and 4.05 mg/g, respectively Insoluble phenolic acids derived from salicylic acid were found in higher concentrations in apple pomace from both cultivars.

Alpha-tocopherol supplementation decreases electronegative low-density lipoprotein concentration [LDL(-)] in haemodialysis patients

Background. Oxidative stress is a significant contributor to cardiovascular diseases (CVD) in haemodialysis (HD) patients, predisposing to the generation of oxidized low-density lipoprotein (oxLDL) or electronegatively charged LDL subfraction. Antioxidant therapy such as alpha-tocopherol acts as a scavenger of lipid peroxyl radicals attenuating the oxidative stress, which decreases the formation of oxLDL. The present study was designed to investigate the influence of the alpha-tocopherol supplementation on the concentration of electronegative low-density lipoprotein [LDL(-)], a minimally oxidized LDL, which we have previously described to be high in HD patients. Methods. Blood samples were collected before and after 120 days of supplementation by alpha-tocopherol (400 UI/day) in 19 stable HD patients (50 +/- 7.8 years; 9 males). The concentrations of LDL(-) in blood plasma [using an anti-LDL- human monoclonal antibody (mAb)] and the anti-LDL(-) IgG auto-antibodies were determined by ELISA. Calculation of body mass index (BMI) and measurements of waist circumference (WC), triceps skin folds (TSF) and arm muscle area (AMA) were performed. Results. The plasma alpha-tocopherol levels increased from 7.9 mu M (0.32-18.4) to 14.2 mu M (1.22-23.8) after the supplementation (P = 0.02). The mean concentration of LDL(-) was reduced from 570.9 mu g/mL (225.6-1241.0) to 169.1 mu g/mL (63.6-621.1) (P < 0.001). The anti-LDL(-) IgG auto-antibodies did not change significantly after the supplementation. The alpha-tocopherol supplementation also reduced the total cholesterol and LDL-C levels in these patients, from 176 +/- 42.3 mg/dL to 120 +/- 35.7 mg/dL (P < 0.05) and 115.5 +/- 21.4 mg/dL to 98.5 +/- 23.01 mg/dL (P < 0.001), respectively. Conclusion. The oral administration of alpha-tocopherol in HD patients resulted in a significant decrease in the LDL(-), total cholesterol and LDL-C levels. This effect may favour a reduction in cardiovascular risk in these patients, but a larger study is required to confirm an effect in this clinical setting.

Modulation of human neutrophil oxidative metabolism and degranulation by extract of Tamarindus indica L. fruit pulp

The tamarind (Tamarindus indica L) is indigenous to Asian countries and widely cultivated in the American continents. The tamarind fruit pulp extract (ExT), traditionally used in spices, food components and juices, is rich in polyphenols that have demonstrated anti-atherosclerotic, antioxidant and immunomodulatory activities. This study evaluated the modulator effect of a crude hydroalcoholic ExT on some peripheral human neutrophil functions. The neutrophil reactive oxygen species generation, triggered by opsonized zymosan (OZ), n-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol myristate acetate (PMA), and assessed by luminol- and lucigenin-enhanced chemiluminescence (LumCL and LucCL, respectively), was inhibited by ExT in a concentration-dependent manner. ExT was a more effective inhibitor of the PMA-stimulated neutrophil function [IC(50) (in mu g/10(6)cells) = 115.7 +/- 9.7 (LumCL) and 174.5 +/- 25.9 (LucCL)], than the OZ- [IC(50) = 248.5 +/- 23.1 (LumCL) and 324.1 +/- 34.6 (LucCL)] or fMLP-stimulated cells [IC(50) = 178.5 +/- 12.2 (LumCL)]. The ExT also inhibited neutrophil NADPH oxidase activity (evaluated by O(2) consumption), degranulation and elastase activity (evaluated by spectrophotometric methods) at concentrations higher than 200 mu g/10(6) cells, without being toxic to the cells, under the conditions assessed. Together, these results indicate the potential of ExT as a source of compounds that can modulate the neutrophil-mediated inflammatory diseases. (C) 2008 Elsevier Ltd. All rights reserved.

Direct and Simultaneous Determination of Cd Cu, and Se in Blood Samples by Graphite Furnace Atomic Absorption Spectrometry

A graphite furnace atomic absorption spectrometric method is proposed for the direct and simultaneous determination of Cd, Cu, and Se in human blood. Samples were diluted 1:10 (v/v) in 0.5% (v/v) HNO(3) + 0.5% (v/v) Triton X-100 solution. For 12 mu L injected sample volume + 5 mu L, of 1000 mg L(-1) Pd(NO(3))(2) + 3 mu L of 1000 mg L(-1) Mg(NO(3))(2), the calculated characteristic masses (mo) were 0.9 pg Cd, 16 pg Cu, and 39 pg Se, which are close to those mo values for single-element conditions for THGA furnace (1.3 pg Cd, 17 pg Cu, and 45 pg Se). Calibration curves with linear correlations better than 0.999 were obtained. The limits of detection (LOD) were 0.03 mu g L(-1) Cd, 0.075 mu g L(-1) Cu and 0.3 mu g L(-1) Se, and the relative standard deviations (n= 12) were 2.5%, 0.3%, and 1.5%, respectively. The method was applied for Cd, Cu, and Se determination in 10 human blood samples and the results were in agreement at the 95% confidence level with those obtained by inductively coupled plasma mass spectrometry. Concentrations of analytes in the selected blood samples varied from 1.7 to 3.2 mu g L(-1) Cd, 700 to 921.7 mu g L(-1) Cu, and from 68.6 to 350 mu g L(-1) Se. The accuracy of the proposed method was also evaluated by an addition-recovery experiment and recoveries of Cd, Cu, and Se added to blood samples ranged from 99-109%, 91-103%,and 93-103%, respectively.

Myotoxic phospholipases A(2) isolated from Bothrops brazili snake venom and synthetic peptides derived from their C-terminal region: Cytotoxic effect on microorganism and tumor cells

This paper reports the purification and biochemical/pharmacological characterization of two myotoxic phospholipases A(2) (PLA(2)S) from Bothrops brazili venom, a native snake from Brazil. Both myotoxins (MTX-I and II) were purified by a single chromatographic step on a CM-Sepharose ion-exchange column up to a high purity level, showing M-r similar to 14,000 for the monomer and 28,000 Da for the dimer. The N-terminal and internal peptide amino acid sequences showed similarity with other myotoxic PLA2S from snake venoms, MTX-I belonging to Asp49 PLA(2) class, enzymatically active, and MTX-II to Lys49 PLA(2)S, catalytically inactive. Treatment of MTX-I with BPB and EDTA reduced drastically its PLA(2) and anticoagulant activities, corroborating the importance of residue His48 and Ca2+ ions for the enzymatic catalysis. Both PLA(2)S induced myotoxic activity and dose-time dependent edema similar to other isolated snake venom toxins from Bothrops and Crotalus genus. The results also demonstrated that MTXs and cationic synthetic peptides derived from their 115-129 C-terminal region displayed cytotoxic activity on human T-cell leukemia (JURKAT) lines and microbicidal effects against Escherichia coli, Candida albicans and Leishmania sp. Thus, these PLA(2) proteins and C-terminal synthetic peptides present multifunctional properties that might be of interest in the development of therapeutic strategies against parasites, bacteria and cancer. (C) 2008 Elsevier Inc. All rights reserved.

Snake venomics and antivenomics of Crotalus durissus subspecies from Brazil: Assessment of geographic variation and its implication on snakebite management

We report the comparative proteomic and antivenomic characterization of the venoms of subspecies cascavella and collilineatus of the Brazilian tropical rattlesnake Crotalus durissus. The venom proteomes of C. d. collilineatus and C. d. cascavella comprise proteins in the range of 4-115 kDa belonging to 9 and 8 toxin families, respectively. Collilineatus and cascavella venoms contain 20-25 main toxins belonging to the following protein families: disintegrin, PLA(2), serine proteinase, cysteine-rich secretory protein (CRISP), vascular endothelial growth factor-like (VEGF), L-amino acid oxidase, C-type lectin-like, and snake venom metalloproteinase (SVMP). As judged by reverse-phase HPLC and mass spectrometry, cascavella and collilineatus share about 90% of their venom proteome. However, the relative occurrence of the toxin families departs among the two C. durissus subspecies venoms. The most notable difference is the presence of the myotoxin crotamine in some C. d. collilineatus specimens (averaging 20.8% of the total proteins of pooled venom), which is absent in the venom of C. d. cascavella. On the other hand, the neurotoxic PLA2 crotoxin represents the most abundant protein in both C. durissus venoms, comprising 67.4% of the toxin proteome in C. d. collilineatus and 72.5% in C. d. cascavella. Myotoxic PLA(2)s are also present in the two venoms albeit in different relative concentrations (18.1% in C. d. cascavella vs. 4.6% in C. d. collilineatus). The venom composition accounts for the clinical manifestations caused by C. durissus envenomations: systemic neurotoxicity and myalgic symptoms and coagulation disturbances, frequently accompanied by myoglobinuria and acute renal failure. The overall compositions of C. d. subspecies cascavella and collilineatus venoms closely resemble that of C. d. terrificus, supporting the view that these taxa can be considered geographical variations of the same species. Pooled venom from adult C.d. cascavella and neonate C.d. terrificus lack crotamine, whereas this skeletal muscle cell membrane depolarizing inducing myotoxin accounts for similar to 20% of the total toxins of venom pooled from C.d. collilineatus and C.d. terrificus from Southern Brazil. The possible relevance of the observed venom variability among the tropical rattlesnake subspecies was assessed by antivenomics using anti-crotalic antivenoms produced at Instituto Butantan and Instituto Vital Brazil. The results revealed that both antivenoms exhibit impaired immunoreactivity towards crotamine and display restricted (similar to 60%) recognition of PLA(2) molecules (crotoxin and D49-myotoxins) from C. d. cascavella and C. d. terrificus venoms. This poor reactivity of the antivenoms may be due to a combination of factors: on the one hand, an inappropriate choice of the mixture of venoms for immunization and, on the other hand, the documented low immunogenicity of PLA(2) molecules. C. durissus causes most of the lethal snakebite accidents in Brazil. The implication of the geographic variation of venom composition for the treatment of bites by different C. durissus subspecies populations is discussed. (C) 2010 Elsevier B.V. All rights reserved.

Antitumor effects of snake venom chemically modified Lys49 phospholipase A(2)-like BthTX-I and a synthetic peptide derived from its C-terminal region

The present work evaluates both in vitro and in vivo antitumor activity of BPB-modified BthTX-I and its cationic synthetic peptide derived from the 115-129 C-terminal region. BPB-BthTX-1 presented cytotoxicity of 10-40% on different tumor cell lines, which were also susceptible to the lytic action of the synthetic peptide. Injection of the modified protein or the peptide in mice, 5 days after transplantation of S 180 tumor cells, reduced 30 and 36% of the tumor size on day 14th and 76 and 79% on day 60th, respectively, when compared to the untreated control group. Thus, these antitumor properties might be of interest in the development of therapeutic strategies against cancer. (C) 2009 The International Association for Biologicals. Published by Elsevier Ltd. All rights reserved.

Comparison of BR and QR Eigenvalue Algorithms for Power System Small Signal Stability Analysis

The BR algorithm is a novel and efficient method to find all eigenvalues of upper Hessenberg matrices and has never been applied to eigenanalysis for power system small signal stability. This paper analyzes differences between the BR and the QR algorithms with performance comparison in terms of CPU time based on stopping criteria and storage requirement. The BR algorithm utilizes accelerating strategies to improve its performance when computing eigenvalues of narrowly banded, nearly tridiagonal upper Hessenberg matrices. These strategies significantly reduce the computation time at a reasonable level of precision. Compared with the QR algorithm, the BR algorithm requires fewer iteration steps and less storage space without depriving of appropriate precision in solving eigenvalue problems of large-scale power systems. Numerical examples demonstrate the efficiency of the BR algorithm in pursuing eigenanalysis tasks of 39-, 68-, 115-, 300-, and 600-bus systems. Experiment results suggest that the BR algorithm is a more efficient algorithm for large-scale power system small signal stability eigenanalysis.

Peak bone mineral accrual and age at menarche in adolescent girls: A 6-year longitudinal study

Background and objectives: The greatest increase in bone mineral content occurs during adolescence. The amount of bone accrued may significantly affect bone mineral status in later life. We carried out a longitudinal investigation of the magnitude and timing of peak bone mineral content velocity (PBMCV) in relation to peak height velocity (PHV) and the age at menarche in a group of adolescent girls over a 6-year period. Methods: The 53 girls in this study are a subset of the 115 girls (initially 8 to 16 years) in a g-year longitudinal study of bone mineral accretion. The ages at PBMCV and PHV were determined by using a cubic spline curve fitting procedure. Determinations were based on height (n = 12) and bone (n = 6) measurements over 6 years. Results: The timing of PBMCV and menarche were coincident, preceded approximately 1 year earlier by PHV. Correlation showed a negative relationship between age at menarche and both peak bone mineral accrual (r = -0.42, P

X-ray properties of the Parkes sample of flat-spectrum radio sources: dust in radio-loud quasars?

We investigate the X-ray properties of the Parkes sample of Bat-spectrum radio sources using data from the ROSAT All-Sky Survey and archival pointed PSPC observations. In total, 163 of the 323 sources are detected. For the remaining 160 sources, 2 sigma upper limits to the X-ray flux are derived. We present power-law photon indices in the 0.1-2.4 keV energy band for 115 sources, which were determined either with a hardness ratio technique or from direct fits to pointed PSPC data if a sufficient number of photons were available. The average photon index is <Gamma > = 1.95(-0.12)(+0.13) for flat-spectrum radio-loud quasars, <Gamma > = 1.70(-0.24)(+0.23) for galaxies, and <Gamma > = 2.40(-0.31)(+0.12) for BL Lac objects. The soft X-ray photon index is correlated with redshift and with radio spectral index in the sense that sources at high redshift and/or with flat (or inverted) radio spectra have flatter X-ray spectra on average. The results are in accord with orientation-dependent unification schemes for radio-loud active galactic nuclei. Webster et al. discovered many sources with unusually red optical continua among the quasars of this sample, and interpreted this result in terms of extinction by dust. Although the X-ray spectra in general do not show excess absorption, we find that low-redshift optically red quasars have significantly lower soft X-ray luminosities on average than objects with blue optical continua. The difference disappears for higher redshifts, as is expected for intrinsic absorption by cold gas associated with the dust. In addition, the scatter in log(f(x)/f(o)) is consistent with the observed optical extinction, contrary to previous claims based on optically or X-ray selected samples. Although alternative explanations for the red optical continua cannot be excluded with the present X-ray data, we note that the observed X-ray properties are consistent with the idea that dust plays an important role in some of the radio-loud quasars with red optical continua.

STD syndrome packets: Improving syndromic management of sexually transmitted diseases in developing countries

Objective: To design, introduce, and evaluate STD syndrome packets containing recommended drugs for each syndrome, four condoms, a partner treatment card, and a patient information leaflet, with the goal of improving sexually transmitted disease (STD) case management. Methods: Packet design evolved around available packaging technology, informed by pilot testing with nurses working in primary care clinics, doctors in private medical practices, and patients with an STD, in Hlabisa, South Africa. Evaluation 1 year later included analysis of distribution records and interviews with 16 nurses and 61 patients. Results: A cheap packet (2 U, S, cents each, excluding contents) compatible with current legislation was designed and introduced to six public sector clinics and as a short pilot to five private medical practices, Four thousand eighty-five packets were distributed to the clinics, equivalent to approximately 115% of the STDs reported over that period. All 16 nurses reported using the packets, but only 63% did so all the time because of occasional supply problems, All believed the packets improved treatment by saving time (75%), improving supply of condoms and partner cards (44%), and making treatment easier (56%), Patients also responded positively, and most said they would buy a packet (up to $5) at a pharmacy (84%) or store (63%) if available. Conclusions: The STD syndrome packets have the potential to improve STD syndromic management by standardizing therapy and improving the supply of condoms, partner cards, and information leaflets. Packets are popular with practitioners and patients, but consistent supply is essential for maximal impact, There may be scope for social marketing of the packets, which could further increase use.

Calcium accretion in girls and boys during puberty: A longitudinal analysis

The primary purpose of this study was to estimate the magnitude and variability of peak calcium accretion rates in the skeletons of healthy white adolescents. Total-body bone mineral content (BMC) was measured annually on six occasions by dual-energy X-ray absorptiometry (DXA; Hologic 2000, array mode), a BMC velocity curve was generated for each child by a cubic spline fit, and peak accretion rates were determined. Anthropometric measures were collected every 6 months and a 24-h dietary recall was recorded two to three times per year. Of the 113 boys and 115 girls initially enrolled in the study, 60 boys and 53 girls who had peak height velocity (PHV) and peak BMC velocity values were used in this longitudinal analysis. When the individual BR IC velocity curves were aligned on the age of peak bone mineral velocity, the resulting mean peak bone mineral accrual rate was 407 g/year for boys (SD, 92 g/year; range, 226-651 g/year) and 322 g/year for girls (SD, 66 g/year; range, 194-520 g/year). Using 32.2% as the fraction of calcium in bone mineral, as determined by neutron activation analysis (Ellis et al., J Bone Miner Res 1996;11:843-848), these corresponded to peak calcium accretion rates of 359 mg/day for boys (81 mg/day; 199-574 mg/day) and 284 mg/day for girls (58 mg/day; 171-459 mg/day). These longitudinal results are 27-34% higher than our previous cross-sectional analysis in which we reported mean values of 282 mg/day for boys and 212 mg/day for girls (Martin et al., Am J Clin Nutr 1997;66:611-615). Mean age of peak calcium accretion was 14.0 years for the boys (1.0 years; 12.0-15.9 years), and 12.5 years for the girls (0.9 years; 10.5-14.6 years). Dietary calcium intake, determined as the mean of all assessments up to the age of peak accretion was 1140 mg/day (SD, 392 mg/day) for boys and 1113 mg/day (SD, 378 mg/day) for girls. We estimate that 26% of adult calcium is laid down during the 2 adolescent years of peak skeletal growth. This period of rapid growth requires high accretion rates of calcium, achieved in part by increased retention efficiency of dietary calcium.