External Bone Size Is a Key Determinant of Strength‐Decline Trajectories of Aging Male Radii

Given prior work showing associations between remodeling and external bone size, we tested the hypothesis that wide bones would show a greater negative correlation between whole‐bone strength and age compared with narrow bones. Cadaveric male radii (n = 37 pairs, 18 to 89 years old) were evaluated biomechanically, and samples were sorted into narrow and wide subgroups using height‐adjusted robustness (total area/bone length). Strength was 54% greater (p < 0.0001) in wide compared with narrow radii for young adults (<40 years old). However, the greater strength of young‐adult wide radii was not observed for older wide radii, as the wide (R2 = 0.565, p = 0.001), but not narrow (R2 = 0.0004, p = 0.944) subgroup showed a significant negative correlation between strength and age. Significant positive correlations between age and robustness (R2 = 0.269, p = 0.048), cortical area (Ct.Ar; R2 = 0.356, p = 0.019), and the mineral/matrix ratio (MMR; R2 = 0.293, p = 0.037) were observed for narrow, but not wide radii (robustness: R2 = 0.015, p = 0.217; Ct.Ar: R2 = 0.095, p = 0.245; MMR: R2 = 0.086, p = 0.271). Porosity increased with age for the narrow (R2 = 0.556, p = 0.001) and wide (R2 = 0.321, p = 0.022) subgroups. The wide subgroup (p < 0.0001) showed a significantly greater elevation of a new measure called the Cortical Pore Score, which quantifies the cumulative effect of pore size and location, indicating that porosity had a more deleterious effect on strength for wide compared with narrow radii. Thus, the divergent strength–age regressions implied that narrow radii maintained a low strength with aging by increasing external size and mineral content to mechanically offset increases in porosity. In contrast, the significant negative strength–age correlation for wide radii implied that the deleterious effect of greater porosity further from the centroid was not offset by changes in outer bone size or mineral content. Thus, the low strength of elderly male radii arose through different biomechanical mechanisms. Consideration of different strength–age regressions (trajectories) may inform clinical decisions on how best to treat individuals to reduce fracture risk. © 2019 American Society for Bone and Mineral Research.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149566/1/jbmr3661_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149566/2/jbmr3661.pd

Petrobrás planeja adiar a abertura de capital da BR Distribuidora

Queda no preço do petróleo e dúvidas sobre o desempenho da economia chinesa devem obrigar a estatal a rever estratégia de desinvestimento; mesmo a venda de gasodutos, uma das operações mais adiantadas da empresa, ainda não está garantida para este an

Sex and External Size Specific Limitations in Assessing Bone Health From Adult Hand Radiographs

Morphological parameters measured for the second metacarpal from hand radiographs are used clinically for assessing bone health during growth and aging. Understanding how these morphological parameters relate to metacarpal strength and strength at other anatomical sites is critical for providing informed decision- making regarding treatment strategies and effectiveness. The goals of this study were to evaluate the extent to which 11 morphological parameters, nine of which were measured from hand radiographs, relate to experimentally measured whole- bone strength assessed at multiple anatomical sites and to test whether these associations differed between men and women. Bone morphology and strength were assessed for the second and third metacarpals, radial diaphysis, femoral diaphysis, and proximal femur for 28 white male donors (18- 89- years old) and 35 white female donors (36- 89+ years old). The only morphological parameter to show a significant correlation with strength without a sex- specific effect was cortical area. Dimensionless morphological parameters derived from hand radiographs correlated significantly with strength for females, but few did for males. Males and females showed a significant association between the circularity of the metacarpal cross- section and the outer width measured in the mediolateral direction. This cross- sectional shape variation contributed to systematic bias in estimating strength using cortical area and assuming a circular cross- section. This was confirmed by the observation that use of elliptical formulas reduced the systematic bias associated with using circular approximations for morphology. Thus, cortical area was the best predictor of strength without a sex- specific difference in the correlation but was not without limitations owing to out- of- plane shape variations. The dependence of cross- sectional shape on the outer bone width measured from a hand radiograph may provide a way to further improve bone health assessments and informed decision making for optimizing strength- building and fracture- prevention treatment strategies. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/174792/1/jbm410653.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/174792/2/jbm410653_am.pd

Variability of soybean germplasm in relation to phosphorus uptake and use efficiency Variabilidade em germoplasma de soja para eficiência na absorção e utilização de fósforo

Plant efficiency for phosphorus uptake and utilization may contribute to improve crop yield potential in situations of low P availability. Twenty nine soybean [Glycine max (L.) Merr.] cultivars were evaluated and classified in relation to the response to phosphorus (P) levels in nutrient solution. P uptake and use efficiency were estimated by the variables: shoot and root dry matter (DM) yield, P-concentrations and contents in plant parts and P-efficiency index (EI). The experiment was conducted in a greenhouse, during 1999, at Campinas, State of São Paulo, Brazil. The experimental design consisted of randomized complete blocks, arranged in split-plots, with three replications. The main plots were the P levels in the nutrient solution (64.5; 129; 258 and 516 mmol L-1), and the subplots were the twenty-nine soybean cultivars, grouped according days to maturity. The plants were harvested at flowering, separated in shoots and roots for dry matter determination and chemical analysis. The analyses of variance indicated differences in plant responses to P-levels and cultivars. Multivariate analysis showed high correlation among the variables shoot-DM, total-DM and shoot P-concentration and P-efficiency index (EI). Cultivars were classified in efficient-responsive (ER)-- 'IAC-1', 'IAC-2', 'IAC-4', 'IAC-5', 'IAC-6', 'IAC-9', 'Sta. Rosa' and 'UFV-1'; efficient-non-responsive (ENR) -- 'IAC-7', 'IAC-11', 'IAC-15', 'S. Carlos' and 'Cristalina'; inefficient-responsive (IR) -- 'IAC-8', 'IAC-10', 'IAC-14', 'Bossier' and 'Foscarin'; and inefficient-non-responsive (INR) -- 'IAC-12', 'IAC-13', 'IAC-16', 'IAC-17', 'IAC-18', 'IAC-19', 'IAC-20', 'IAC-22', 'Paraná', 'IAS-5' and 'BR-4'. The efficient-responsive soybean cultivars showed the highest values for shoot and total DM and EI, and the lowest shoot P-concentrations.<br>A eficiência da planta na absorção e utilização de fósforo em situação de baixa disponibilidade do nutriente pode contribuir para aumentar o potencial produtivo da cultura. Vinte e nove cultivares de soja [Glycine max (L.) Merr.] foram avaliados e classificados quanto à resposta a concentrações de fósforo (P) em solução nutritiva. Determinaram-se as variáveis relacionadas com a eficiência na absorção e utilização de P: produção de matéria seca (MS) da parte aérea e das raízes, teores de P nas partes das plantas e os índices de eficiência de utilização de P (IE). O experimento foi instalado em casa de vegetação em Campinas, em 1999. Foi utilizado o delineamento em blocos ao acaso, em parcelas subdivididas com três repetições. As parcelas principais constituíram-se das concentrações de P na solução nutritiva (64,5; 129; 258 e 516 mmol L-1) e as subparcelas, dos vinte e nove cultivares de soja, agrupados de acordo com o ciclo. As plantas foram colhidas no florescimento, separadas em parte aérea e raízes para determinação da matéria seca e análise química de nutrientes. A análise de variância indicou diferenças nas respostas das plantas para concentrações de P e cultivares. A análise multivariada mostrou alta correlação entre a MS de parte aérea e MS-total com os teores de P na parte aérea e índices de eficiência de utilização de P (IE). Os cultivares foram classificados em eficientes e responsivos (ER) -- 'IAC-1', 'IAC-2', 'IAC-4', 'IAC-5', 'IAC-6', 'IAC-9', 'Sta. Rosa' e 'UFV-1'; eficientes não responsivos (ENR) -- 'IAC-7', 'IAC-11', 'IAC-15', 'S. Carlos' e 'Cristalina'; ineficientes responsivos (IR) -- 'IAC-8', 'IAC-10', 'IAC-14', 'Bossier' e 'Foscarin'; e ineficientes não responsivos (INR) -- 'IAC-12', 'IAC-13', 'IAC-16', 'IAC-17', 'IAC-18', 'IAC-19', 'IAC-20', 'IAC-22', 'Paraná', 'IAS-5' e 'BR-4'. Os cultivares eficientes e responsivos mostraram os maiores valores para MS de parte aérea, MS total e IE, e os menores teores de P na parte aérea