158 research outputs found

    Nitrogen and phosphorus accumulation and remobilization of durum wheat as affected by soil gravel content

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    Soil gravel content affects many soil physical properties, as well as crop yield. Little is known regarding the influence of soil gravel content on growth and nutrient uptake of durum wheat (Triticum durum Desf.). The accumulation of nitrogen and phosphorous during the vegetative and reproductive periods and the contribution of pre-anthesis assimilates to grain N and P con- tent have been evaluated in two durum wheat varieties grown on soils with 0, 10, 20 and 30% gravel content. The two varieties showed similar behaviour and the increase of soil gravel de- creased plant biomass during the entire biological cycle. Nitrogen and P concentration of all plant parts was not affected by soil gravel content, while N and P content was greatly reduced, owing to the effect on dry matter yield. Post-anthesis accumulation and remobilization of N and P were greatly reduced: the decrease from gravel-free soil to 30% gravel content was about 41 kg N ha–1 and 4 kg P ha–1 for the former and 14 kg N ha–1 and 2 kg P ha–1 for the latter. The differences in growth rate were attributed to differences in development of the root system due to the restricted soil volume

    Grain yield of durum wheat as affected by waterlogging at tillering

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    Waterlogging is one of the limiting factors influencing durum wheat (Triticum durum L.) production. In this paper we investigated the impact of seven waterlogging durations of 4, 8, 12, 16, 20, 40, and 60 days, imposed at 3-leaf and 4-leaf growth stages, on grain yield, grain yield components, straw and root dry weight and nitrogen concentration of grain, straw, and roots of two varieties of durum wheat. Grain yield of both varieties showed a significant reduction only when waterlogging was prolonged to more than 20 days, and 40-d and 60-d waterlogging reduced grain yield by 19% and 30%. Waterlogging depressed grain yield preventing many culms from producing spikes. It slowed down spikelet formation, consequently reducing the number of spikelets per spike, and reduced floret formation per spikelet, thus reducing the number of kernels per spike

    Carotid artery stenting: a single-centre experience with up to 8 years' follow-up

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    Carotid artery stenting (CAS) may be an alternative to surgical endoarterectomy not only in high-risk patients. We report results in the endovascular treatment of carotid artery disease with up to 8 years' follow-up. In this retrospective study, we analysed data from 853 consecutive patients (946 arteries) treated for carotid artery stenosis between April 1999 and March 2007; 491 (52%) arteries were symptomatic and 455(48%) were asymptomatic. Preprocedural evaluation of the patients was performed with echo Doppler, magnetic resonance angiography (MRA) or computed tomographic angiography (CTA) and a neurological examination. A cerebral protection device was used in 879 (92.9%) procedures. Anti-platelet therapy was administered before and after the procedure. All patients were included in a follow-up of up to 8 years. Technical success was achieved in 943 (99.6%) lesions. At 30 days, there was a 0.21% (n = 2) death rate, a 0.42% major stroke rate, a 1.69% minor stroke/transient ischaemic attack (TIA) rate and a combined 2.32% TIA/stroke and death rate. During follow-up, echo Doppler evidenced restenosis in 39 (4.85%) cases; of these, only five, presenting restenosis > 80%, were treated with an endovascular reintervention. At the long-term follow-up, two strokes (0.23%) were reported, which both occurred within the first 2 years. In our experience, carotid artery stenting seems to be a safe and effective treatment, providing satisfactory long-term clinical results

    Chromosome Xq23 is associated with lower atherogenic lipid concentrations and favorable cardiometabolic indices

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    Autosomal genetic analyses of blood lipids have yielded key insights for coronary heart disease (CHD). However, X chromosome genetic variation is understudied for blood lipids in large sample sizes. We now analyze genetic and blood lipid data in a high-coverage whole X chromosome sequencing study of 65,322 multi-ancestry participants and perform replication among 456,893 European participants. Common alleles on chromosome Xq23 are strongly associated with reduced total cholesterol, LDL cholesterol, and triglycerides (min P = 8.5 × 10-72), with similar effects for males and females. Chromosome Xq23 lipid-lowering alleles are associated with reduced odds for CHD among 42,545 cases and 591,247 controls (P = 1.7 × 10-4), and reduced odds for diabetes mellitus type 2 among 54,095 cases and 573,885 controls (P = 1.4 × 10-5). Although we observe an association with increased BMI, waist-to-hip ratio adjusted for BMI is reduced, bioimpedance analyses indicate increased gluteofemoral fat, and abdominal MRI analyses indicate reduced visceral adiposity. Co-localization analyses strongly correlate increased CHRDL1 gene expression, particularly in adipose tissue, with reduced concentrations of blood lipids

    Long-Term Outcomes of Diabetic Patients With Critical Limb Ischemia Followed in a Tertiary Referral Diabetic Foot Clinic

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    We describe the long-term outcomes of 510 diabetic patients with critical limb ischemia (CLI) and an active foot ulcer or gangrene, seen at the University Hospital of Rome Tor Vergata, a tertiary care clinic

    Deep learning of the retina enables phenome- and genome-wide analyses of the microvasculature.

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    Background: The microvasculature, the smallest blood vessels in the body, has key roles in maintenance of organ health as well as tumorigenesis. The retinal fundus is a window for human in vivo non-invasive assessment of the microvasculature. Large-scale complementary machine learning-based assessment of the retinal vasculature with phenome-wide and genome-wide analyses may yield new insights into human health and disease. Methods: We utilized 97,895 retinal fundus images from 54,813 UK Biobank participants. Using convolutional neural networks to segment the retinal microvasculature, we calculated fractal dimension (FD) as a measure of vascular branching complexity, and vascular density. We associated these indices with 1,866 incident ICD-based conditions (median 10y follow-up) and 88 quantitative traits, adjusting for age, sex, smoking status, and ethnicity. Results: Low retinal vascular FD and density were significantly associated with higher risks for incident mortality, hypertension, congestive heart failure, renal failure, type 2 diabetes, sleep apnea, anemia, and multiple ocular conditions, as well as corresponding quantitative traits. Genome-wide association of vascular FD and density identified 7 and 13 novel loci respectively, which were enriched for pathways linked to angiogenesis (e.g., VEGF, PDGFR, angiopoietin, and WNT signaling pathways) and inflammation (e.g., interleukin, cytokine signaling). Conclusions: Our results indicate that the retinal vasculature may serve as a biomarker for future cardiometabolic and ocular disease and provide insights on genes and biological pathways influencing microvascular indices. Moreover, such a framework highlights how deep learning of images can quantify an interpretable phenotype for integration with electronic health records, biomarker, and genetic data to inform risk prediction and risk modification

    An Inclusive Study on the Effect of Strain Rate on the Stress-Strain Behavior and the Undrained Shear Strength of Clay Soils in Kombolcha, Ethiopia

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    This research aims to study the effect of strain rate on the stress-strain association and shear strength of clay soils in Kombolcha, Ethiopia. Field and laboratory experimentations were conducted on 3 soil samples collected at 4.5m depth, considering the physical and engineering properties of the soil. Unconsolidated, undrained triaxial compression tests were performed under confining pressure on the specimens that were axially loaded at a rate of strain varying from 0.38mm/min to 1.14mm/min by taking 2 points above and below 1% of the specimen height. Stress-strain relations were developed under the stated different rates of strains to describe their effect. It was revealed that the strain rate effect was observed. By increasing the strain rate shifts the stress-strain curve upward, and the corresponding shear strength of the soil also increased under effective stress. Accordingly, the strain rate increased the shear parameters. The average angle of friction increased by 13.43%, 15.08%, 13.18%, and 14.33% when the rate of strain changed from 0.38 to 0.57mm/min, 0.57 to 0.76mm/min, 0.76 to 0.95mm/min, and 0.95 to 1.14mm/min respectively, while the average cohesion increased by 17.67%, 19.52%, 14.87%, and 16.48%. The failure at strain rate 1%/min of sample height (0.76mm/min) was uniformly distributed and there was uniform pore pressure distribution throughout the sample height. The effect is slightly more when the shear strength increased at the left side than at the right side. Average shear strength parameters such as cohesion and angle friction were recorded for strain rates from 0.57mm/min to 1.25mm/min specifically for the clay soils found in Kombolcha town, Ethiopia
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