1,115 research outputs found

    Development of A New Coating System for The High Functional Mold in Thin-wall Casting

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    A new inorganic binder system has been developed to prepare the mold having a high strength for the thin-walled casting. To increase the fracture strength at high temperature, a large amount of inorganic binder should be converted into glass phase and the generated glass phase has to be homogeneously coated on the surface of starting particles. In this work, two types of process were employed to investigate the coating and glassification efficiencies of inorganic precursor. In the first process (process I), the green body consisting of starting powder and organic binder was dipped in the inorganic precursor solution. In the second process (process II), the starting powder was coated by inorganic precursor, and then the organic binder was used to form the green body. The mold sample prepared using process II showed the higher strength value than that using process I, owing to the inclement effect on the glassfication efficiency by the loss of inorganic precursor in process I. The prepared real mold was perfectly produced and the casted product showed a clean surface without defects such as dross, nonmetallic inclusions, and crack. Consequently, the new inorganic binder system could be applied for preparing the mold for the thin-wall casting having high mechanical properties

    Agmatine protects retinal ganglion cells from hypoxia-induced apoptosis in transformed rat retinal ganglion cell line

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    <p>Abstract</p> <p>Background</p> <p>Agmatine is an endogenous polyamine formed by the decarboxylation of L-arginine. We investigated the protective effects of agmatine against hypoxia-induced apoptosis of immortalized rat retinal ganglion cells (RGC-5). RGC-5 cells were cultured in a closed hypoxic chamber (5% O<sub>2</sub>) with or without agmatine. Cell viability was determined by lactate dehydrogenase (LDH) assay and apoptosis was examined by annexin V and caspase-3 assays. Expression and phosphorylation of mitogen-activated protein kinases (MAPKs; JNK, ERK p44/42, and p38) and nuclear factor-kappa B (NF-κB) were investigated by Western immunoblot analysis. The effects of agmatine were compared to those of brain-derived neurotrophic factor (BDNF), a well-known protective neurotrophin for retinal ganglion cells.</p> <p>Results</p> <p>After 48 hours of hypoxic culture, the LDH assay showed 52.3% cell loss, which was reduced to 25.6% and 30.1% when agmatine and BDNF were administered, respectively. This observed cell loss was due to apoptotic cell death, as established by annexin V and caspase-3 assays. Although total expression of MAPKs and NF-κB was not influenced by hypoxic injury, phosphorylation of these two proteins was increased. Agmatine reduced phosphorylation of JNK and NF-κB, while BDNF suppressed phosphorylation of ERK and p38.</p> <p>Conclusion</p> <p>Our results show that agmatine has neuroprotective effects against hypoxia-induced retinal ganglion cell damage in RGC-5 cells and that its effects may act through the JNK and NF-κB signaling pathways. Our data suggest that agmatine may lead to a novel therapeutic strategy to reduce retinal ganglion cell injury related to hypoxia.</p

    Attenuated Age-Related Thinning of Peripapillary Retinal Nerve Fiber Layer in Long Eyes

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    PURPOSE: To assess the impact of axial length on the age-related peripapillary retinal nerve fiber layer (RNFL) thinning. METHODS: This cross-sectional observational comparative case series included 172 eyes from 172 healthy Korean subjects. Peripapillary RNFL thickness was measured using an Optic Disc Cube 200 x 200 scan of spectral domain Cirrus HD OCT and the axial length was measured using IOL Master Advanced Technology. In age groups based on decade, the normal ranges of peripapillary RNFL thickness for average, quadrant, and clock-hour sectors were determined with 95% confidence intervals. After dividing the eyes into two groups according to axial length (cut-off, 24.50 mm), the degrees of age-related RNFL thinning were compared. RESULTS: Among the eyes included in the study, 53 (30.81%) were considered to be long eyes (axial length, 25.04 +/- 0.48 microm) and 119 (69.19%) were short-to-normal length eyes (axial length, 23.57 +/- 0.60 microm). The decrease in average RNFL thickness with age was less in long eyes (negative slope, -0.12 microm/yr) than in short-to-normal length eyes (negative slope, -0.32 microm/yr) (p < 0.001). CONCLUSIONS: Age-related thinning of peripapillary RNFL thickness is attenuated in long eyes compared to short-to-normal length eyes.ope

    The enhancer activity of long interspersed nuclear element derived microRNA 625 induced by NF-κB

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    Transposable elements (TEs) are DNA sequences that cut or introduced into the genome, and they represent a massive portion of the human genome. TEs generate a considerable number of microRNAs (miRNAs) are derived from TEs (MDTEs). Numerous miRNAs are related to cancer, and hsa-miRNA-625 is a well-known oncomiR derived from long interspersed nuclear elements (LINEs). The relative expression of hsa-miRNA-625-5p differs in humans, chimpanzees, crab-eating monkeys, and mice, and four primers were designed against the 3′UTR of GATAD2B to analyze the different quantities of canonical binding sites and the location of miRNA binding sites. Luciferase assay was performed to score for the interaction between hsa-miRNA-625 and the 3′UTR of GATAD2B, while blocking NF-κB. In summary, the different numbers of canonical binding sites and the locations of miRNA binding sites affect gene expression, and NF-κB induces the enhancer activity of hsa-miRNA-625-5p by sharing the binding sites

    Development of a standardized in-hospital cardiopulmonary resuscitation set-up

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    Objective. This study evaluated whether chest compression in a standardized inhospital cardiopulmonary resuscitation (CPR) set-up can be performed as effectively as when the rescuer is kneeling beside the patient lying on the floor. Specifically, the in-hospital test was standardized according to the rescuers’ average knee height. Methods. Experimental intervention (test 1) was a standardized, in-hospital CPR set-up: first, the bed height was fixed at 70 cm. Second, the height difference between the bed and a step stool was set to the average knee height of the CPR team members (45 cm). Control intervention (test 2) was kneeling on floor. Thirty-eight medical doctors on the CPR team each performed 2 minutes of chest compressions in test 1 and 2 in random order (cross-over trial). A Little Anne was used as a simulated patient who had experienced cardiac arrest. Chest compression parameters, such as average depth and rate, were measured using an accelerometer device. Results. In all tests, the average depths were those recommended in the most recent CPR guidelines (50–60 mm); there were no significant differences between Tests 1 and 2 (53.1 ± 4.3 mm vs. 52.6 ± 4.8 mm, respectively; p = 0.398). The average rate in Test 2 (119.1 ± 12.4 numbers/min) was slightly faster than that in Test 1 (116.4 ± 10.2 numbers/ min; p = 0.028). No differences were observed in any other parameters. Conclusions. Chest compression quality in our standardized in-hospital CPR set-up was similar with that performed in a kneeling position on the floor. Trial Registration: Clinical Research Information Service: KCT000159

    Acute Viral Myopericarditis Presenting as a Transient Effusive-Constrictive Pericarditis Caused by Coinfection with Coxsackieviruses A4 and B3

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    Acute myopericarditis is usually caused by viral infections, and the most common cause of viral myopericarditis is coxsackieviruses. Diagnosis of myopericarditis is made based on clinical manifestations of myocardial (such as myocardial dysfunction and elevated serum cardiac enzyme levels) and pericardial (such as inflammatory pericardial effusion) involvement. Although endomyocardial biopsy is the gold standard for the confirmation of viral infection, serologic tests can be helpful. Conservative management is the mainstay of treatment in acute myopericarditis. We report here a case of a 24-year-old man with acute myopericarditis who presented with transient effusive-constrictive pericarditis. Echocardiography showed transient pericardial effusion with constrictive physiology and global regional wall motion abnormalities of the left ventricle. The patient also had an elevated serum troponin I level. A computed tomogram of the chest showed pericardial and pleural effusion, which resolved after 2 weeks of supportive treatment. Serologic testing revealed coxsackievirus A4 and B3 coinfection. The patient received conservative medical treatment, including nonsteroidal anti-inflammatory drugs, and he recovered completely with no complications

    Alleviating psoriatic skin inflammation through augmentation of Treg cells via CTLA-4 signaling peptide

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    Psoriasis is a chronic inflammatory skin disease characterized by hyperplasia of keratinocytes and immune cell infiltration. The IL-17-producing T cells play a key role in psoriasis pathogenesis, while regulatory T (Treg) cells are diminished during psoriatic inflammation. Current psoriasis treatments largely focus on IL-17 and IL-23, however, few studies have explored therapeutic drugs targeting an increase of Treg cells to control immune homeostasis. In this study, we investigated the effects of a cytotoxic T lymphocyte antigen-4 (CTLA-4) signaling peptide (dNP2-ctCTLA-4) in Th17, Tc17, γδ T cells, Treg cells in vitro and a mouse model of psoriasis. Treatment with dNP2-ctCTLA-4 peptide showed a significant reduction of psoriatic skin inflammation with increased Treg cell proportion and reduced IL-17 production by T cells, indicating a potential role in modulating psoriatic skin disease. We compared dNP2-ctCTLA-4 with CTLA-4-Ig and found that only dNP2-ctCTLA-4 ameliorated the psoriasis progression, with increased Treg cells and inhibited IL-17 production from γδ T cells. In vitro experiments using a T cell-antigen presenting cell co-culture system demonstrated the distinct mechanisms of dNP2-ctCTLA-4 compared to CTLA-4-Ig in the induction of Treg cells. These findings highlight the therapeutic potential of dNP2-ctCTLA-4 peptide in psoriasis by augmenting Treg/Teff ratio, offering a new approach to modulating the disease
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