215 research outputs found

    A Critical Heat Generation for Safe Nuclear Fuels after a LOCA

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    This study applies a thermo-elasto-plastic-creep finite element procedure to the analysis of an accidental behavior of nuclear fuel as well as normal behavior. The result will be used as basic data for the robust design of nuclear power plant and fuels. We extended the range of mechanical strain from small or medium to large adopting the Hencky logarithmic strain measure in addition to the Green-Lagrange strain and Almansi strain measures, for the possible large strain situation in accidental environments. We found that there is a critical heat generation after LOCA without ECCS (event category 5), under which the cladding of fuel sustains the internal pressure and temperature for the time being for the rescue of the power plant. With the heat generation above the critical value caused by malfunctioning of the control rods, the stiffness of cladding becomes zero due to the softening by high temperature. The weak position of cladding along the length continuously bulges radially to burst and to discharge radioactive substances. This kind of cases should be avoid by any means

    Genetic diversity and divergence among Korean cattle breeds assessed using a BovineHD single-nucleotide polymorphism chip

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    Objective In Korea, there are three main cattle breeds, which are distinguished by coat color: Brown Hanwoo (BH), Brindle Hanwoo (BRH), and Jeju Black (JB). In this study, we sought to compare the genetic diversity and divergence among there Korean cattle breeds using a BovineHD chip genotyping array. Methods Sample data were collected from 168 cattle in three populations of BH (48 cattle), BRH (96 cattle), and JB (24 cattle). The single-nucleotide polymorphism (SNP) genotyping was performed using the Illumina BovineHD SNP 777K Bead chip. Results Heterozygosity, used as a measure of within-breed genetic diversity, was higher in BH (0.293) and BRH (0.296) than in JB (0.266). Linkage disequilibrium decay was more rapid in BH and BRH than in JB, reaching an average r2 value of 0.2 before 26 kb in BH and BRH, whereas the corresponding value was reached before 32 kb in JB. Intra-population, inter-population, and Fst analyses were used to identify candidate signatures of positive selection in the genome of a domestic Korean cattle population and 48, 11, and 11 loci were detected in the genomic region of the BRH breed, respectively. A Neighbor-Joining phylogenetic tree showed two main groups: a group comprising BH and BRH on one side and a group containing JB on the other. The runs of homozygosity analysis between Korean breeds indicated that the BRH and JB breeds have high inbreeding within breeds compared with BH. An analysis of differentiation based on a high-density SNP chip showed differences between Korean cattle breeds and the closeness of breeds corresponding to the geographic regions where they are evolving. Conclusion Our results indicate that although the Korean cattle breeds have common features, they also show reliable breed diversity

    Primary cilia mediate mitochondrial stress responses to promote dopamine neuron survival in a Parkinson’s disease model

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    A primary cilium is an antenna-like structure on the cell surface that plays a crucial role in sensory perception and signal transduction. Mitochondria, the ‘powerhouse’ of the cell, control cell survival, and death. The cellular ability to remove dysfunctional mitochondria through mitophagy is important for cell survival. We show here that mitochondrial stress, caused by respiratory complex inhibitors and excessive fission, robustly stimulates ciliogenesis in different types of cells including neuronal cells. Mitochondrial stress-induced ciliogenesis is mediated by mitochondrial reactive oxygen species generation, subsequent activation of AMP-activated protein kinase and autophagy. Conversely, abrogation of ciliogenesis compromises mitochondrial stress-induced autophagy, leading to enhanced cell death. In mice, treatment with mitochondrial toxin, MPTP elicits ciliary elongation and autophagy in the substantia nigra dopamine neurons. Blockade of cilia formation in these neurons attenuates MPTP-induced autophagy but facilitates dopamine neuronal loss and motor disability. Our findings demonstrate the important role of primary cilia in cellular pro-survival responses during mitochondrial stress. © 2019, The Author(s).1

    Diagnostic Value of Nitroglycerin-Induced Headache as a Negative Predictor of Coronary Atherosclerosis

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    The purpose of the present study was to clarify the possible relationship between nitroglycerin (NTG)-induced headache and both vascular functional and organic atherosclerosis. The study included 96 patients with NTG-induced headache (group I: 54.7±9.5 years, 52 males) and 204 patients without headache (group II: 58.1±9.1 years, 127 males) who suffered from new-onset chest pain. Flow-mediated dilation and nitroglycerin-mediated dilation were significantly greater in group I than in group II (8.8±4.1% vs. 7.1±3.5%, p=0.001, and 23.1±7.3% vs. 17.1±11.8%, p<0.001, respectively). The carotid intima-media thickness was significantly smaller in group I than in group II (0.55±0.15 mm vs. 0.67±0.22 mm, p=0.001). Heart-carotid pulse wave velocity was significantly lower in group I than in group II (784.5±160.1 m/s vs. 979.1±215.6 m/s, p=0.003). In the multiple regression analysis, the absence of NTG-induced headache was a predictor of coronary artery disease (CAD) (odds ratio: 17.89, 95% confidence interval: 7.89-40.02, p<0.001). NTG-induced headache developed more frequently in patients with normal coronary arteries or minimal CAD than in patients with obstructive CAD. The presence of NTG-induced headache might be helpful and provide additional information in evaluating patients with chest pain syndrome

    Melatonin receptor 1 B polymorphisms associated with the risk of gestational diabetes mellitus

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    <p>Abstract</p> <p>Backgrounds</p> <p>Two SNPs in <it>melatonin receptor 1B </it>gene, <it>rs10830963 </it>and <it>rs1387153 </it>showed significant associations with fasting plasma glucose levels and the risk of Type 2 Diabetes Mellitus (T2DM) in previous studies. Since T2DM and gestational diabetes mellitus (GDM) share similar characteristics, we suspected that the two genetic polymorphisms in <it>MTNR1B </it>may be associated with GDM, and conducted association studies between the polymorphisms and the disease. Furthermore, we also examined genetic effects of the two polymorphisms with various diabetes-related phenotypes.</p> <p>Methods</p> <p>A total of 1,918 subjects (928 GDM patients and 990 controls) were used for the study. Two <it>MTNR1B </it>polymorphisms were genotyped using TaqMan assay. The allele distributions of SNPs were evaluated by <it>x</it><sup>2 </sup>models calculating odds ratios (ORs), 95% confidence intervals (CIs), and corresponding <it>P </it>values. Multiple regressions were used for association analyses of GDM-related traits. Finally, conditional analyses were also performed.</p> <p>Results</p> <p>We found significant associations between the two genetic variants and GDM, <it>rs10830963</it>, with a corrected <it>P </it>value of 0.0001, and <it>rs1387153</it>, with the corrected <it>P </it>value of 0.0008. In addition, we also found that the two SNPs were associated with various phenotypes such as homeostasis model assessment of beta-cell function and fasting glucose levels. Further conditional analyses results suggested that <it>rs10830963 </it>might be more likely functional in case/control analysis, although not clear in GDM-related phenotype analyses.</p> <p>Conclusion</p> <p>There have been studies that found associations between genetic variants of other genes and GDM, this is the first study that found significant associations between SNPs of <it>MTNR1B </it>and GDM. The genetic effects of two SNPs identified in this study would be helpful in understanding the insight of GDM and other diabetes-related disorders.</p

    Incidentally detected breast lesions on chest CT with US correlation: a pictorial essay

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    With the increasing use of computed tomography (CT), incidental breast lesions are detected more frequently. When interpreting chest CT findings, it is important for radiologists to carefully review the breast to recognize any abnormal findings that could affect patient management. The purpose of this study is to discuss incidental breast lesions on chest CT with ultrasonography correlation that may be encountered in routine clinical practice

    Effects of Combined Therapy with Ezetimibe Plus Simvastatin After Drug-Eluting Stent Implantation in a Porcine Coronary Restenosis Model

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    The aim of this study was to examine the anti-proliferative and anti-inflammatory effects of ezetimibe/simvastatin (E/S) after drug-eluting stent (DES) implantation in a porcine coronary restenosis model. Pigs were randomized into two groups in which the coronary arteries (23 pigs) had DES. Stents were deployed with oversizing (stent/artery ratio 1.3:1) in porcine coronary arteries. Fifteen pigs were taken 10/20 mg of E/S and eight pigs were not taken E/S. Histopathologic analysis was assessed at 28 days after stenting. In neointima, most inflammatory cells were lymphohistiocytes. Lymphohistiocyte count was not different between two groups (337±227 vs. 443±366 cells, P=0.292), but neointima area was significantly smaller (1.00±0.49 mm2 vs. 1.69±0.98 mm2, P=0.021) and percent area stenosis was significantly lower (23.3±10% vs. 39±19%, P=0.007) in E/S group compared with control group. There were no significant differences in fibrin score (1.99±0.79 vs. 1.81±0.88, P=0.49), endothelial score (1.75±0.66 vs. 1.80±0.59, P=0.79), and the percent of endothelium covered lumen (43±21% vs. 45±21%, P=0.84) between E/S group and control group. Combined therapy with ezetimibe and simvastatin inhibits neointimal hyperplasia, but does not inhibit inflammatory infiltration and arterial healing after DES implantation in a porcine coronary restenosis model

    Transabdominal Embryofetoscopy for the Detection of Short Rib-polydactyly Syndrome, Type II(Majewski), in the First Trimester

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    Our aim was to demonstrate the potential of first-trimester embryofetoscopy for prenatal diagnosis in a continuing pregnancy. A patient at risk for giving birth to an infant with short rib-polydactyly syndrome, type II (Majewski), presented for prenatal diagnosis at 9 weeks of gestation. A 1 mm semirigid fiberoptic endoscope with an 18 gauge examination sheath and a single-chip digital camera were used for transabdominal embryofetoscopy. Transabdominal embryofetoscopy was performed at 13 weeks of gestation. Direct visualization of the fetus was achieved and no gross limb or facial abnormalities were seen. This case shows that embryofetoscopy is a useful tool for early diagnosis in high-risk patients in the first trimester for continuing pregnancies

    Endothelial Dysfunction and Increased Carotid Intima-Media Thickness in the Patients with Slow Coronary Flow

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    Flow mediated brachial dilatation (FMD) and carotid intima-media thickness (IMT) have been a surrogate for early atherosclerosis. Slow coronary flow in a normal coronary angiogram is not a rare condition, but its pathogenesis remains unclear. A total of 85 patients with angina were evaluated of their brachial artery FMD, carotid IMT and conventional coronary angiography. Coronary flow was quantified using the corrected thrombosis in myocardial infarction (TIMI) frame count method. Group I was a control with normal coronary angiography (n = 41, 56.1 ± 8.0 yr) and group II was no significant coronary stenosis with slow flow (n = 44, 56.3 ± 10.0 yr). Diabetes was rare but dyslipidemia and family history were frequent in group II. Heart rate was higher in group II than in group I. White blood cells, especially monocytes and homocysteine were higher in group II. The FMD was significantly lower in group II than in group I. Elevated heart rate, dyslipidemia and low FMD were independently related with slow coronary flow in regression analysis. Therefore, endothelial dysfunction may be an earlier vascular phenomenon than increased carotid IMT in the patients with slow coronary flow
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