922 research outputs found

    Gender-specific association of the K121Q Ectonucleotide Pyrophosphatase Phosphodiesterase (ENPP) 1 polymorphism with subcutaneous adiposity in a South African Black population

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    Purpose: This study aimed to determine whether the ENPP-1 K121Q (rs1044498) polymorphism was associated with adiposity and cardiometabolic disease markers within a South African Black population. Methods: Black participants from the greater Johannesburg–Soweto area in South Africa, for whom metabolic syndrome status, cardiometabolic disease markers, adipokine levels and body fat distribution had already been measured, were genotyped by PCR-RFLP for the presence of the K121Q polymorphism.Results: Within a cohort of 345 Black South Africans, the frequency of the ENPP-1 K121Q C allele was 0.89. In the total cohort, the K121Q polymorphism was not significantly associated with any cardiometabolic disease markers or adipokine levels. However, in the female population the CC genotype was shown to be associated with increased abdominal subcutaneous fat levels (p=0.007). Conclusion: This cohort of Black South Africans had a higher frequency of the C allele when compared to reported data for Asian and Caucasian populations, however this frequency was comparable to other African data. The presence of the rs1044498 polymorphism was not associated with markers of cardiometabolic disease, suggesting that these associations may be population dependent. The gender-specific genotypic association with subcutaneous fat levels is a novel finding requiring further investigation

    Alendronate or alfacalcidol in glucocorticoid-induced osteoporosis

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    BACKGROUND: Treatment with glucocorticoids is associated with bone loss starting soon after therapy is initiated and an increased risk of fracture. METHODS: We performed a randomized, double-placebo, double-blind clinical trial of 18 months' duration among patients with a rheumatic disease who were starting glucocorticoids at a daily dose that was equivalent to at least 7.5 mg of prednisone. A total of 201 patients were assigned to receive either alendronate (10 mg) and a placebo capsule of alfacalcidol daily or alfacalcidol (1 mu g) and a placebo tablet of alendronate daily. The primary outcome was the change in bone mineral density of the lumbar spine in 18 months; the secondary outcome was the incidence of morphometric vertebral deformities. RESULTS: A total of 100 patients received alendronate, and 101 received alfacalcidol; 163 patients completed the study. The bone mineral density of the lumbar spine increased by 2.1 percent in the alendronate group (95 percent confidence interval, 1.1 to 3.1 percent) and decreased by 1.9 percent in the alfacalcidol group (95 percent confidence interval, -3.1 to -0.7 percent). At 18 months, the mean difference of change in bone mineral density between the two groups was 4.0 percent (95 percent confidence interval, 2.4 to 5.5 percent). Three patients in the alendronate group had a new vertebral deformity, as compared with eight patients in the alfacalcidol group (of whom three had symptomatic vertebral fractures) (hazard ratio, 0.4; 95 percent confidence interval, 0.1 to 1.4). CONCLUSIONS: During this 18-month trial in patients with rheumatic diseases, alendronate was more effective in the prevention of glucocorticoid-induced bone loss than was alfacalcidol

    Validation of a simple canopy conductance model for estimating transpiration of different citrus species under non-limiting soil water conditions

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    XXXI International Horticultural Congress (IHC2022): International Symposium on Water: a Worldwide Challenge for Horticulture!Please read abstract in the article.South Africa’s Water Research Commission and Citrus Research International.https://www.ishs.org/acta-horticulturae2023-07-31hj2024Plant Production and Soil ScienceSDG-02:Zero Hunge

    Genetic variation associated with differential educational attainment in adults has anticipated associations with school performance in children

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    Genome-wide association study results have yielded evidence for the association of common genetic variants with crude measures of completed educational attainment in adults. Whilst informative, these results do not inform as to the mechanism of these effects or their presence at earlier ages and where educational performance is more routinely and more precisely assessed. Single nucleotide polymorphisms exhibiting genome-wide significant associations with adult educational attainment were combined to derive an unweighted allele score in 5,979 and 6,145 young participants from the Avon Longitudinal Study of Parents and Children with key stage 3 national curriculum test results (SATS results) available at age 13 to 14 years in English and mathematics respectively. Standardised (z-scored) results for English and mathematics showed an expected relationship with sex, with girls exhibiting an advantage over boys in English (0.433 SD (95%CI 0.395, 0.470), p<10-10) with more similar results (though in the opposite direction) in mathematics (0.042 SD (95%CI 0.004, 0.080), p = 0.030). Each additional adult educational attainment increasing allele was associated with 0.041 SD (95%CI 0.020, 0.063), p = 1.79Ă—10-04 and 0.028 SD (95%CI 0.007, 0.050), p = 0.01 increases in standardised SATS score for English and mathematics respectively. Educational attainment is a complex multifactorial behavioural trait which has not had heritable contributions to it fully characterised. We were able to apply the results from a large study of adult educational attainment to a study of child exam performance marking events in the process of learning rather than realised adult end product. Our results support evidence for common, small genetic contributions to educational attainment, but also emphasise the likely lifecourse nature of this genetic effect. Results here also, by an alternative route, suggest that existing methods for child examination are able to recognise early life variation likely to be related to ultimate educational attainment

    First-principles study of (BiScO3){1-x}-(PbTiO3){x} piezoelectric alloys

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    We report a first-principles study of a class of (BiScO3)_{1-x}-(PbTiO3)_x (BS-PT) alloys recently proposed by Eitel et al. as promising materials for piezoelectric actuator applications. We show that (i) BS-PT displays very large structural distortions and polarizations at the morphotropic phase boundary (MPB) (we obtain a c/a of ~1.05-1.08 and P_tet of ~1.1 C/m^2); (ii) the ferroelectric and piezoelectric properties of BS-PT are dominated by the onset of hybridization between Bi/Pb-6p and O-2p orbitals, a mechanism that is enhanced upon substitution of Pb by Bi; and (iii) the piezoelectric responses of BS-PT and Pb(Zr_{1-x}Ti_x)O3 (PZT) at the MPB are comparable, at least as far as the computed values of the piezoelectric coefficient d_15 are concerned. While our results are generally consistent with experiment, they also suggest that certain intrinsic properties of BS-PT may be even better than has been indicated by experiments to date. We also discuss results for PZT that demonstrate the prominent role played by Pb displacements in its piezoelectric properties.Comment: 6 pages, with 3 postscript figures embedded. Uses REVTEX and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/ji_bi/index.htm

    Using Genetic Variation to Explore the Causal Effect of Maternal Pregnancy Adiposity on Future Offspring Adiposity: A Mendelian Randomisation Study

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    Background: It has been suggested that greater maternal adiposity during pregnancy affects lifelong risk of offspring fatness via intrauterine mechanisms. Our aim was to use Mendelian randomisation (MR) to investigate the causal effect of intrauterine exposure to greater maternal body mass index (BMI) on offspring BMI and fat mass from childhood to early adulthood. Methods and Findings: We used maternal genetic variants as instrumental variables (IVs) to test the causal effect of maternal BMI in pregnancy on offspring fatness (BMI and dual-energy X-ray absorptiometry [DXA] determined fat mass index [FMI]) in a MR approach. This was investigated, with repeat measurements, from ages 7 to 18 in the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 2,521 to 3,720 for different ages). We then sought to replicate findings with results for BMI at age 6 in Generation R (n = 2,337 for replication sample; n = 6,057 for total pooled sample). In confounder-adjusted multivariable regression in ALSPAC, a 1 standard deviation (SD, equivalent of 3.7 kg/m2) increase in maternal BMI was associated with a 0.25 SD (95% CI 0.21–0.29) increase in offspring BMI at age 7, with similar results at later ages and when FMI was used as the outcome. A weighted genetic risk score was generated from 32 genetic variants robus

    Are simple empirical crop coefficient approaches for determining pecan water use readily transferrable across a wide range of conditions?

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    The accurate estimation of evapotranspiration (ET) of orchard crops is critical for judicious irrigation water management and planning. However, it is impossible to measure ET under all possible combinations of climate and management practices, which necessitates the use of ET models. Although empirical models are more likely to be adopted by consultants and growers, due to easier parameterization and the requirements for fewer, more easily measured input parameters, they may not always be transferable across a wide range of conditions. As a result these models may not always give acceptably accurate ET values outside of the area in which they were calibrated. This study therefore aimed to evaluate empirical crop coefficient models for pecans in two different orchards which differ in climate and/or fractional canopy cover from where the models were developed. When testing the FAO-56 approach it was found that pecans should not be grouped under stone fruit and that a six stage crop growth should be considered, instead of the traditional four stage curve. Improved accuracy in estimating ET of pecans could, however, be achieved by using a pecan specific reference crop coefficients for a mature orchard and scaling this with fractional canopy cover for different orchards, provided that an adjustment was made for the influence of climate on canopy development. This was achieved by using a published growing degree (GDD) day crop coefficient relationship, provided seasonal accumulated thermal time is below 1600 GDD and that crop coefficients do not exceed 1.1.The Water Research Commission (Project K5/1770) with co-funding from the National Department of Agriculture, Forestry and Fisheries of South Africa.http://www.actahort.orgam2017Plant Production and Soil Scienc

    Crop coefficient approaches based on fixed estimates of leaf resistance are not appropriate for estimating water use of citrus

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    The estimation of crop water use is critical for accurate irrigation scheduling and water licenses. However, the direct measurement of crop water use is too expensive and time consuming to be performed under all possible conditions, which necessitates the use of water use models. The FAO-56 procedure is a simple, convenient and reproducible method, but as canopy cover and height vary greatly among different orchards, crop coefficients may not be readily transferrable from one orchard to another. Allen and Pereira (2009) therefore incorporated a procedure into the FAO-56 approach which estimates crop coefficients based on a physical description of the vegetation and an adjustment for relative crop stomatal control over transpiration. Transpiration crop coefficients derived using this procedure and fixed values for citrus, did not provide good estimates of water use in three citrus orchards. However, when mean monthly leaf resistance was taken into account, good agreement was found with measured values. A relationship between monthly reference evapotranspiration and mean leaf resistance provided a means of estimating mean leaf resistance which estimated transpiration crop coefficients with a reasonable degree of accuracy. The use of a dynamic estimate of mean leaf resistance therefore provided reasonable estimates of transpiration in citrus.South Africa‟s Water Research Commission (Project K5/1770, Water use of fruit tree orchards), with cofounding from the South African National Department of Agriculture, Forestry and Fisheries.http://link.springer.com/journal/2712016-12-30hb201

    Modelling water use of subtropical fruit crops : the challenges

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    Subtropical fruit crops form an important part of the fruit industry in many countries. Many of these crops are grown in semi-arid regions or subtropical regions where rainfall is seasonal and as a result the vast majority of these perennial, evergreen orchards are under irrigation. This represents a significant irrigation requirement and with more emphasis being placed on the conservation of water and orchard profitability, it is becoming increasingly important to accurately estimate water use of these crops and schedule irrigation accordingly. The FAO-56 procedure is a simple, convenient and reproducible method for estimating water use. However, the transferability of crop coefficients between different orchards and growing regions is not always readily achieved, due largely to differences in canopy size and management practices. In addition, as subtropical crops tend to exhibit a higher degree of stomatal control over transpiration than most other agricultural crops, some measure of canopy or leaf resistance must be taken into account when using models based on atmospheric demand. The challenge is therefore to provide reliable and dynamic estimates of canopy resistance from relatively simple parameters which can be of use to irrigation consultants and farmers for determining the water requirements of these crops. The challenge remains to ensure that these dynamic estimates are realistic and readily applicable to a number of growing regions. The derivation of transpiration crop coefficients, based on canopy cover and height and a dynamic estimate of leaf resistance, provided reasonable estimates of transpiration in three orchards in contrasting climates, suggesting that this approach could prove useful in future for subtropical crops.http://www.actahort.org2018-05-10hj2017Plant Production and Soil Scienc

    The Experiment Data Depot: A Web-Based Software Tool for Biological Experimental Data Storage, Sharing, and Visualization

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    Although recent advances in synthetic biology allow us to produce biological designs more efficiently than ever, our ability to predict the end result of these designs is still nascent. Predictive models require large amounts of high-quality data to be parametrized and tested, which are not generally available. Here, we present the Experiment Data Depot (EDD), an online tool designed as a repository of experimental data and metadata. EDD provides a convenient way to upload a variety of data types, visualize these data, and export them in a standardized fashion for use with predictive algorithms. In this paper, we describe EDD and showcase its utility for three different use cases: storage of characterized synthetic biology parts, leveraging proteomics data to improve biofuel yield, and the use of extracellular metabolite concentrations to predict intracellular metabolic fluxes
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