873 research outputs found

    Regulation of endothelial nitric oxide synthase by agmatine after transient global cerebral ischemia in rat brain

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    Nitric oxide (NO) production by endothelial nitric oxide synthase (eNOS) plays a protective role in cerebral ischemia by maintaining vascular permeability, whereas NO derived from neuronal and inducible NOS is neurotoxic and can participate in neuronal damage occurring in ischemia. Matrix metalloproteinases (MMPs) are up-regulated by ischemic injury and degrade the basement membrane if brain vessels to promote cell death and tissue injury. We previously reported that agmatine, synthesized from L-arginine by arginine decarboxylase (ADC) which is expressed in endothelial cells, has shown a direct increased eNOS expression and decreased MMPs expression in bEnd3 cells. But, there are few reports about the regulation of eNOS by agmatine in ischemic animal model. In the present study, we examined the expression of eNOS and MMPs by agmatine treatment after transient global ischemia in vivo. Global ischemia was induced with four vessel occlusion (4-VO) and agmatine (100 mg/kg) was administered intraperitoneally at the onset of reperfusion. The animals were euthanized at 6 and 24 hours after global ischemia and prepared for other analysis. Global ischemia led severe neuronal damage in the rat hippocampus and cerebral cortex, but agmatine treatment protected neurons from ischemic injury. Moreover, the level and expression of eNOS was increased by agmatine treatment, whereas inducible NOS (iNOS) and MMP-9 protein expressions were decreased in the brain. These results suggest that agmatine protects microvessels in the brain by activation eNOS as well as reduces extracellular matrix degradation during the early phase of ischemic insult

    Microstructure evolution modeling of square-diamond pass hot bar rolling of AISI 4135 steel

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    In this study, kinetics of the static (SRX) and metadynamic recrystallization (MDRX) of AISI4135 steel was investigated using hot torsion tests. Continuous torsion tests were carried out to determine the critical strain for dynamic recrystallization (DRX). The times for 50% recrystallization of SRX and MDRX were determined, respectively, by means of interrupted torsion tests. Furthermore, austenite grain size (AGS) evolution due to recrystallization (RX) was measured by optical microscopy. With the help of the evolution model established, the AGS for hot bar rolling of AISI4135 steel was predicted numerically. The predicted AGS values were compared with the results using the other model available in the literature and experimental results to verify its validity. Then, numerical predictions depending on various process parameters such as interpass time, temperature, and roll speed were made to investigate the effect of these parameters on AGS distributions for square-diamond pass rolling. Such numerical results were found to be beneficial in understanding the effect of processing conditions on the microstructure evolution better and control the rolling processes more accurately.<br /

    Fractional exhaled nitric oxide measurements in rhinitis and asthma in children.

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    Exaled nitric oxide (FeNO) is considered a good noninvasive marker to assess airway inflammation in asthma and allergic rhinitis. In asthma, exhaled NO is very useful to verify adherence to therapy, and to predict upcoming asthma exacerbations. It has been also proposed that adjusting anti-inflammatory drugs guided by the monitoring of exhaled NO, could improve overall asthma control. Other studies showed increased FeNO levels in subjects with allergic rhinitis

    Synthesis of Bifunctional Poly(Vinyl Phosphonic Acid-co-glycidyl Metacrylate-co-divinyl Benzene) Cation-Exchange Resin and Its Indium Adsorption Properties from Indium Tin Oxide Solution

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    ABSTRACT Poly(vinyl phosphonic acid-co-glycidyl methacrylate-co-divinyl benzene) (PVGD) and PVGD containing an iminodiacetic acid group (IPVGD), which has indium ion selectivity, were synthesized by suspension polymerization, and their indium adsorption properties were investigated. The synthesized PVGD and IPVGD resins were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury porosimetry. The cation-exchange capacity, the water uptake and the indium adsorption properties were investigated. The cation-exchange capacities of PVGD and IPVGD were 1.2 -4.5 meq/g and 2.5 -6.4 meq/g, respectively. The water uptakes were decreased with increasing contents of divinyl benzene (DVB). The water uptake values were 25% -40% and 20% -35%, respectively. The optimum adsorption of indium from a pure indium solution and an artificial indium tin oxide (ITO) solution by the PVGD and IPVGD ion-exchange resins were 2.3 and 3.5 meq/g, respectively. The indium adsorption capacities of IPVGD were higher than those of PVGD. The indium ion adsorption selectivity in the artificial ITO solution by PVGD and IPVGD was excellent, and other ions were adsorbed only slightly

    Incidence and clinicopathologic behavior of uterine cervical carcinoma in renal transplant recipients

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    <p>Abstract</p> <p>Background</p> <p>Renal allograft recipients are reported to have a higher incidence of malignancy than the general population. This single hospital-based study examined the incidence and clinicopathologic behavior of uterine cervical carcinoma in renal transplant recipients.</p> <p>Methods</p> <p>Among 453 women receiving renal transplantation from January 1990 to December 2008, 5 patients were diagnosed with cervical carcinoma. Medical records of these 5 patients were retrospectively reviewed, and clinicopathologic data were collected and analyzed.</p> <p>Results</p> <p>The incidence of cervical carcinoma in renal transplant recipients was 58.1 out of 100,000 per year, which is 3.5 times higher than in the general Korean population. The mean interval between the time of renal transplantation and the time of cervical carcinoma diagnosis was 80.7 months. After a median follow-up of 96.2 months, there was no recurrence of the disease or death. In 4 patients who were positive from human papillomavirus in situ hybridization (HPV ISH), high or probably high risk HPV DNA was detected in all. Punctate staining of HPV ISH was detected in 3 out of 4 patients.</p> <p>Conclusions</p> <p>Higher incidence of cervical carcinoma is expected in renal transplant recipients, so appropriate surveillance is needed to ensure early detection and treatment of cervical carcinoma.</p

    Dysprosium and Gadolinium Double Doped Bismuth Oxide Electrolytes for Low Temperature Solid Oxide Fuel Cells

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    Herein, we developed a novel double dopant bismuth oxide electrolyte system with dysprosium (Dy) and gadolinium (Gd). The effect of the co-dopants on phase stability and electrical properties was investigated. Phase transformation from cubic to rhombohedral was observed as Gd dopant concentration increased and consequently resulted in conductivity degradation. The stabilization of high temperature cubic phase was achieved with a total dopant concentration as low as ∼12 mol% with 8 mol% Dy and 4 mol% Gd double dopant composition (8D4GSB) and this composition showed one of the highest total conductivity reported at this low temperature regime. In addition, the long-term stability of DGSB electrolytes was investigated.1

    Deep Seawater flow Characteristics Around the Manganese Nodule Collecting Device

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    AbstractFlow field characteristics with outflow discharge from a collecting device in deep seawater while gathering manganese nodules have been analyzed by CFD. Numerical model is used for the analysis with CFD program of FLUENT. It is assumed that the collecting device is 4.5×5.4×6.7m with outflow speed = 1.75 m/s and the current speed = 0.1m/s.Overall seawater flow field characteristics are largely influenced by the outflow discharge from the collecting device and manganese nodule particle behavior. The outflow discharge effect reaches to about few times of the collecting device in back. As simulation results, flow velocity and streamline distributions are compared including turbulence kinetic energyvariation. This study will be useful for optimal design for manganese nodule collecting device system in deep sea

    The impact of sequential versus single anastomoses on flow characteristics and mid-term patency of saphenous vein grafts in coronary bypass grafting

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    ObjectiveTo assess the influence of bypass grafting technique on the flow characteristics and mid-term patency of saphenous vein coronary bypass grafts.MethodsIn the present study, 309 patients who underwent either sequential (group A, N = 84 grafts) or individual (group B, N = 244 grafts) saphenous vein coronary bypass grafting between February 2002 and September 2007 were investigated. Individual bypassing only was performed in 212 patients, and sequential bypassing only was performed in 78 patients. The remaining 19 patients received both. A total of 436 distal anastomoses were performed with 328 saphenous vein grafts. The intraoperative flow characteristics and the graft patency were assessed with the transit time flow meter and serial multi-detector computed tomography coronary angiograms, respectively.ResultsGroup A showed a higher mean flow compared with group B at 49.4 ± 27.4 mL/min versus 37.1 ± 20.1 mL/min, respectively (P = .001). The mean flow increased linearly as the number of anastomoses increased per graft (P < .001). Graft patency at 3 years was 93.3% ± 3.4% in group A and 86.5% ± 3.1% in group B (P = .048). After adjustment for baseline characteristics, group A showed a tendency for superior mid-term patency than group B (hazard ratio 0.362; 95% confidence interval, 0.129–1.017; P = .0538).ConclusionsSequential bypass grafts were associated with higher mean flows and superior mid-term patency compared with individual grafts. These findings suggest the more favorable results of sequential bypass grafting to be attributed to the enhanced flow hemodynamics
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