149 research outputs found

    Specific absorbed fraction of energy of silicon-boron alloys

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    213-217We have studied the energy absorption buildup factors and specific absorbed fraction of energy for the silicon-boron alloys of different composition such as alloy A-Si0.95-B0.05, alloy B- Si0.9-B0.1, alloy C- Si0.8-B0.2, alloy D- Si0.7-B0.3, alloy E- Si0.6-B0.4 and alloy F- Si0.5-B0.5. for wide energy range (0.015–15 MeV) up to the penetration depth of 40 mfp using geometric progression fitting method. Buildup factors increase with the increase in the penetration depth. It has been found that the shielding parameters such as mass attenuation coefficient, effective atomic number and buildup factor values are larger for the silicon-boron alloy Si0.95-B0.05 than the other studied silicon-boron alloys. Specific absorbed fraction of energy is maximum for the silicon-boron alloy Si0.95-B0.05. Hence, we can conclude that the silicon-boron alloy Si0.95-B0.05 is a good absorber of X-rays, gamma and neutrons among the studied alloys. The present study is useful in the field of radiation shielding

    Severe propylthiouracil-induced hepatotoxicity in pregnancy managed successfully by liver transplantation: A case report

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    <p>Abstract</p> <p>Introduction</p> <p>Propylthiouracil-induced severe hepatotoxicity is a relatively rare occurrence, with very few cases reported in the literature. The management of this complication in pregnancy can be a challenge because of the effects of the various treatment options on the fetus.</p> <p>Case presentation</p> <p>We report a rare case of fulminant hepatic failure in a 36-year-old gravida 2 black woman of African descent that occurred at 17 weeks gestation following propylthiouracil treatment for Graves' disease. Her liver failure was managed by liver transplantation and thyroidectomy. Her pregnancy was continued to term, though with not so favorable early childhood sequelae.</p> <p>Conclusion</p> <p>This case illustrates a very rare complication of treatment with a presumed safe drug during pregnancy followed by adverse neonatal outcomes due to the extensive treatment.</p

    Baroreflex sensitivity is impaired in survivors of mild COVID-19 at 3-6 months of clinical recovery; association with carotid artery stiffness

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    The association between the stiffening of barosensitive regions of central arteries and the derangements in baroreflex functions remains unexplored in COVID-19 survivors. Fifty-seven survivors of mild COVID-19 (defined as presence of upper respiratory tract symptoms and/or fever without shortness of breath or hypoxia; SpO2 > 93%), with an age range of 22-66 years (27 females) participated at 3-6 months of recovering from the acute phase of RT-PCR positive COVID-19. Healthy volunteers whose baroreflex sensitivity (BRS) and arterial stiffness data were acquired prior to the onset of the pandemic constituted the control group. BRS was found to be significantly lower in the COVID survivor group for the systolic blood pressure-based sequences (BRS SBP ) [9.78 (7.16-17.74) ms/mmHg vs 16.5 (11.25-23.78) ms/mmHg; p = 0.0253]. The COVID survivor group showed significantly higher carotid β stiffness index [7.16 (5.75-8.18) vs 5.64 (4.34-6.96); (p = 0.0004)], and pulse wave velocity β (PWVβ ) [5.67 (4.96-6.32) m/s vs 5.12 (4.37-5.41) m/s; p = 0.0002]. BRS quantified by both the sequence and spectral methods showed an inverse correlation with PWVβ in the male survivors. Impairment of BRS in the male survivors of mild COVID-19 at 3-6 months of clinical recovery shows association with carotid artery stiffness

    Central and local arterial stiffness in White Europeans compared to age-, sex-, and BMI-matched South Asians

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    Background Ethnicity impacts cardiovascular disease (CVD) risk, and South Asians demonstrate a higher risk than White Europeans. Arterial stiffness is known to contribute to CVD, and differences in arterial stiffness between ethnicities could explain the disparity in CVD risk. We compared central and local arterial stiffness between White Europeans and South Asians and investigated which factors are associated with arterial stiffness. Methods Data were collected from cohorts of White Europeans (the Netherlands) and South Asians (India). We matched cohorts on individual level using age, sex, and body mass index (BMI). Arterial stiffness was measured with ARTSENS® Plus. Central stiffness was expressed as carotid-femoral pulse wave velocity (cf-PWV, m/s), and local carotid stiffness was quantified using the carotid stiffness index (Beta) and pressure-strain elastic modulus (Epsilon, kPa). We compared arterial stiffness between cohorts and used multivariable linear regression to identify factors related to stiffness. Results We included n = 121 participants per cohort (age 53±10 years, 55% male, BMI 24 kg/m2). Cf-PWV was lower in White Europeans compared to South Asians (6.8±1.9 vs. 8.2±1.8 m/s, p0.05 for interaction). Systolic blood pressure was associated with carotid stiffness in both cohorts, whereas age was associated to carotid stiffness only in South Asians and BMI only in White Europeans. Conclusion Ethnicity is associated with central but not local arterial stiffness. Conversely, ethnicity seems to modify associations between CVD risk factors and local but not central arterial stiffness. This suggests that ethnicity interacts with arterial stiffness measures and the association of these measures with CVD risk factors

    A Comparison of the Pitfall Trap, Winkler Extractor and Berlese Funnel for Sampling Ground-Dwelling Arthropods in Tropical Montane Cloud Forests

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    Little is known about the ground-dwelling arthropod diversity in tropical montane cloud forests (TMCF). Due to unique habitat conditions in TMCFs with continuously wet substrates and a waterlogged forest floor along with the innate biases of the pitfall trap, Berlese funnel and Winkler extractor are certain to make it difficult to choose the most appropriate method to sample the ground-dwelling arthropods in TMCFs. Among the three methods, the Winkler extractor was the most efficient method for quantitative data and pitfall trapping for qualitative data for most groups. Inclusion of floatation method as a complementary method along with the Winkler extractor would enable a comprehensive quantitative survey of ground-dwelling arthropods. Pitfall trapping is essential for both quantitative and qualitative sampling of Diplopoda, Opiliones, Orthoptera, and Diptera. The Winkler extractor was the best quantitative method for Psocoptera, Araneae, Isopoda, and Formicidae; and the Berlese funnel was best for Collembola and Chilopoda. For larval forms of different insect orders and the Acari, all the three methods were equally effective

    Over-expression of the IGI1 leading to altered shoot-branching development related to MAX pathway in Arabidopsis

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    Shoot branching and growth are controlled by phytohormones such as auxin and other components in Arabidopsis. We identified a mutant (igi1) showing decreased height and bunchy branching patterns. The phenotypes reverted to the wild type in response to RNA interference with the IGI1 gene. Histochemical analysis by GUS assay revealed tissue-specific gene expression in the anther and showed that the expression levels of the IGI1 gene in apical parts, including flowers, were higher than in other parts of the plants. The auxin biosynthesis component gene, CYP79B2, was up-regulated in igi1 mutants and the IGI1 gene was down-regulated by IAA treatment. These results indicated that there is an interplay regulation between IGI1 and phytohormone auxin. Moreover, the expression of the auxin-related shoot branching regulation genes, MAX3 and MAX4, was down-regulated in igi1 mutants. Taken together, these results indicate that the overexpression of the IGI1 influenced MAX pathway in the shoot branching regulation
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