31 research outputs found

    Secondary Osteoporosis: Endocrine and Metabolic Causes of Bone Mass Deterioration

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    License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Secondary osteoporosis results from medical conditions or treatments that interfere with the attainment of peak bone mass and/or may predispose to accelerated bone loss. Although secondary osteoporosis is less common, it is becoming more frequently diagnosed. Apart from the welldefined risk of secondary osteoporosis in patients requiring long-term corticosteroids therapy, an increasing list of dietary, lifestyle, endocrine, metabolic, and other causes of bone mass deterioration has been identified (Table 1). Recently it has been demonstrated that, in contrast to primary osteoporosis which is associated with age, gender, and family history, secondary osteoporosis shows a prevalence in men similar to that in women (men 21 % versus women 17.5%

    Cortical thickness mapping to identify focal osteoporosis in patients with hip fracture.

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    BACKGROUND: Individuals with osteoporosis are predisposed to hip fracture during trips, stumbles or falls, but half of all hip fractures occur in those without generalised osteoporosis. By analysing ordinary clinical CT scans using a novel cortical thickness mapping technique, we discovered patches of markedly thinner bone at fracture-prone regions in the femurs of women with acute hip fracture compared with controls. METHODS: We analysed CT scans from 75 female volunteers with acute fracture and 75 age- and sex-matched controls. We classified the fracture location as femoral neck or trochanteric before creating bone thickness maps of the outer 'cortical' shell of the intact contra-lateral hip. After registration of each bone to an average femur shape and statistical parametric mapping, we were able to visualise and quantify statistically significant foci of thinner cortical bone associated with each fracture type, assuming good symmetry of bone structure between the intact and fractured hip. The technique allowed us to pinpoint systematic differences and display the results on a 3D average femur shape model. FINDINGS: The cortex was generally thinner in femoral neck fracture cases than controls. More striking were several discrete patches of statistically significant thinner bone of up to 30%, which coincided with common sites of fracture initiation (femoral neck or trochanteric). INTERPRETATION: Femoral neck fracture patients had a thumbnail-sized patch of focal osteoporosis at the upper head-neck junction. This region coincided with a weak part of the femur, prone to both spontaneous 'tensile' fractures of the femoral neck, and as a site of crack initiation when falling sideways. Current hip fracture prevention strategies are based on case finding: they involve clinical risk factor estimation to determine the need for single-plane bone density measurement within a standard region of interest (ROI) of the femoral neck. The precise sites of focal osteoporosis that we have identified are overlooked by current 2D bone densitometry methods

    The Open Anchoring Quest Dataset: Anchored Estimates from 96 Studies on Anchoring Effects

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    People’s estimates are biased toward previously considered numbers (anchoring). We have aggregated all available data from anchoring studies that included at least two anchors into one large dataset. Data were standardized to comprise one estimate per row, coded according to a wide range of variables, and are available for download and analyses online (https://metaanalyses.shinyapps.io/OpAQ/). Because the dataset includes both original and meta-data it allows for fine-grained analyses (e.g., correlations of estimates for different tasks) but also for meta-analyses (e.g., effect sizes for anchoring effects)

    R code and datasets for flower-visitor interactions (pollinators, robbers, thieves) and plant traits from Mount Cameroon

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    <p>Raw data and R code for: <strong>Cheaters among pollinators: Nectar robbing and thieving vary spatiotemporally with floral traits in Afrotropical forests. </strong><i>Ecosphere, 2023</i>. doi: 10.1002/ecs2.4696<br> </p><p>When using the dataset for anything, cite the Sakhalkar et al. <i>Ecosphere </i>paper.</p><p><br>All related information can be found in the cited paper. For additional information, refer to the paper or write to either [email protected] or [email protected].</p&gt

    Transparent and low-loss luminescent solar concentrators based on self-trapped exciton emission in lead-free double perovskite nanocrystals

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    Luminescent solar concentrators (LSCs) are light-harvesting devices that redirect solar light to an edge-attached photovoltaic cell, and thus, they have high potential to be incorporated directly into buildings' windows to allow for generating electricity. Perovskite nanocrystals (PNCs) are promising materials for LSCs because their enticing optical properties can be engineered to provide a high photoluminescence (PL) quantum yield (QY) and low overlap between absorption and emission spectra. Replacement of toxic, lead-containing perovskites in LSCs by lead-free PNCs, while retaining high optical efficiency of the device, remains the key challenge, which needs to be overcome to build environmentally friendly solar-harvesting platforms. In this work, we use nanocrystals of Bi-doped Cs2Ag0.4Na0.6InCl6 double perovskites with a self-trapped exciton emission to realize for the first time a transparent, low-reabsorption, lead-free perovskite-based LSC. Fabricated 100 cm(2) LSCs show an internal optical quantum efficiency of 21.2% with the corresponding internal concentration factor of 2.7. Monte Carlo (MC) ray-tracing simulations identified the loss caused by nonunity PL QY to be the most significant contribution to the overall efficiency loss. The MC simulations also allowed us to estimate the efficiency of 39.4% for 2,500 cm(2) LSCs with hypothetical unity PL. These results demonstrate a significant promise held by Bi-doped lead-free PNCs for LSCs.Web of Science476453644
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