1,585 research outputs found

    Tempcore Process Simulator to Analyze Microstructural Evolution of Quenched and Tempered Rebar

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    Featured Application Proposed process simulator can be widely applied to parameter design of industrial Tempcore process with reduced cost and time. Abstract Tempcore process simulator (TPS) has been developed in this study to analyze the microstructural evolution of quenched and tempered rebar. There has been an increasing need to relate the complex microstructures to the resulting properties of quenched and tempered rebar. However, information on such relationships typically requires precise thermal histories imposed on the workpiece. Therefore, TPS, capable of simulating the Tempcore process, has been developed to produce high-fidelity data. TPS mainly consists of a vacuum induction furnace, pilot rolling mill, box furnace, and cooling unit to simulate shop floor operations. A series of experimental tests were successfully carried out with various parameters, such as reheating temperature, water flow, water pressure, and cooling time. The effects of chemical compositions and cooling time on the microstructural evolution and mechanical properties of quenched and tempered rebar have been analyzed to validate the performance of TPS. The results show that TPS can simulate the Tempcore process with a high degree of fidelity and reliability.11Ysciescopu

    Sequential bipolar radiofrequency lumbar sympathectomy in Raynaud's disease -A case report-

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    A 39-year-old female was suffering from cold-induced Raynaud's attacks in both hands and feet, with symptoms being most severe in her left foot. The patient did not respond to medical treatments and was referred to our department of pain medicine. We performed sequential bipolar radiofrequency lumbar sympathectomy to the patient, which offered a long duration of symptom relief. Sequential bipolar radiofrequency lesions could create continuous strip lesion, and thus, could achieve better results, while the potential risk of liquid neurolytic agents could be avoided

    Postreperfusion Blood Pressure Variability After Endovascular Thrombectomy Affects Outcomes in Acute Ischemic Stroke Patients With Poor Collateral Circulation

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    Background and Purpose: We evaluated the effect of 24 h blood pressure variability (BPV) on clinical outcomes in acute ischemic stroke patients with successful recanalization after endovascular recanalization therapy (ERT).Methods: Patients with anterior circulation occlusion were evaluated if they underwent ERT based on multiphase computed tomography angiography and achieved successful recanalization (≥thrombolysis in cerebral ischemia 2b). Collateral degrees were dichotomized based on the pial arterial filling score, with a score of 0–3 defined as a poor collateral status. BPV parameters include mean, standard deviation, coefficient of variation, and variation independent of the mean (VIM) for systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure, and pulse rate (PR). These parameters were measured for 24 h after ERT and were analyzed according to occlusion sites and stroke mechanisms. Associations of BPV parameters with clinical outcomes were investigated with stratification based on the baseline collateral status.Results: BPV was significantly different according to the occlusion sites and stroke mechanisms, and higher BPV was observed in patients with internal carotid artery occlusion or cardioembolic occlusion. After adjustment for confounders, most BPV parameters remained significant to predict functional outcomes at 3 months in patients with poor collateral circulation. However, no significant association was found between BPV parameters and clinical outcomes in patients with good collateral circulation.Conclusion: Postreperfusion BP management by decreasing BPV may have influence on improving clinical outcome in cases of poor collateral circulation among patients achieving successful recanalization after ERT

    Inhibition of hepatic stellate cells by bone marrow-derived mesenchymal stem cells in hepatic fibrosis

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    Background/AimsTherapies involving bone-marrow-derived mesenchymal stem cells (BM-MSCs) have considerable potential in the management of hepatic disease. BM-MSCs have been investigated in regenerative medicine due to their ability to secrete various growth factors and cytokines that regress hepatic fibrosis and enhance hepatocyte functionality. The aim of this study was to determine the antifibrosis effect of BM-MSCs on activated hepatic stellate cells (HSCs) and the mechanism underlying how BM-MSCs modulate the function of activated HSCs.MethodsWe used HSCs in both direct and indirect co-culture systems with BM-MSCs to evaluate the antifibrosis effect of BM-MSCs. The cell viability and apoptosis were evaluated by a direct co-culture system of activated HSCs with BM-MSCs. The activations of both HSCs alone and HSCs with BM-MSCs in the direct co-culture system were observed by immunocytochemistry for alpha-smooth muscle actin (α-SMA). The levels of growth factors and cytokines were evaluated by an indirect co-culture system of activated HSCs with BM-MSCs.ResultsThe BM-MSCs in the direct co-culture system significantly decreased the production of α-SMA and the viability of activated HSCs, whereas they induced the apoptosis of activated HSCs. The BM-MSCs in the indirect co-culture system decreased the production of transforming growth factor-β1 and interleukin (IL)-6, whereas they increased the production of hepatocyte growth factor and IL-10. These results confirmed that the juxtacrine and paracrine effects of BM-MSCs can inhibit the proliferative, fibrogenic function of activated HSCs and have the potential to reverse the fibrotic process by inhibiting the production of α-SMA and inducing the apoptosis of HSCs.ConclusionsThese results have demonstrated that BM-MSCs may exert an antifibrosis effect by modulating the function of activated HSCs

    Mesenteric Pseudocyst of the Small Bowel in Gastric Cancer Patient: A Case Report

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    Mesenteric pseudocyst is rare. This term is used to describe the abdominal cystic mass, without the origin of abdominal organ. We presented a case of mesenteric pseudocyst of the small bowel in a 70-year-old man. Esophago-gastro-duodenoscopy showed a 3.5 cm sized excavated lesion on the posterior wall of angle. Endocopic biopsy confirmed a histologic diagnosis of the poorly differentiated adenocarcinoma, which includes the signet ring cell component. Abdominal computed tomography scan showed a focal mucosal enhancement in the posterior wall of angle of the stomach, a 2.4 cm sized enhancing mass on the distal small bowel loop, without distant metastases or ascites in rectal shelf, and multiple gallbladder stones. The patient underwent subtotal gastrectomy with gastroduodenostomy, segmental resection of the small bowel, and cholecystectomy. The final pathological diagnosis was mesenteric pseudocyst. This is the first case report describing incidentally detected mesenteric pseudocyst of the small bowel in gastric cancer patients

    Regional Characteristics of NO2 Column Densities from Pandora Observations during the MAPS-Seoul Campaign

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    Vertical column density (VCD) of nitrogen dioxide (NO2) was measured using Pandora spectrometers at six sites on the Korean Peninsula during the Megacity Air Pollution Studies-Seoul (MAPS-Seoul) campaign from May to June 2015. To estimate the tropospheric NO2 VCD, the stratospheric NO2 VCD from the Ozone Monitoring Instrument (OMI) was subtracted from the total NO2 VCD from Pandora. European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis wind data was used to analyze variations in tropospheric NO2 VCD caused by wind patterns at each site. The Yonsei/SEO site was found to have the largest tropospheric NO2 VCD (1.49 DU on average) from a statistical analysis of hourly tropospheric NO2 VCD measurements. At rural sites, remarkably low NO2 VCDs were observed. However, a wind field analysis showed that trans-boundary transport and emissions from domestic sources lead to an increase in tropospheric NO2 VCD at NIER/BYI and KMA/AMY, respectively. At urban sites, high NO2 VCD values were observed under conditions of low wind speed, which were influenced by local urban emissions. Tropospheric NO2 VCD at HUFS/Yongin increases under conditions of significant transport from urban area of Seoul according to a correlation analysis that considers the transport time lag. Significant diurnal variations were found at urban sites during the MAPS-Seoul campaign, but not at rural sites, indicating that it is associated with diurnal patterns of NO2 emissions from dense traffic
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