The automobile industry uses resistance spot welding, which is advantageous in terms of cost and productivity, for joining steel sheets the most. However, in actual field, the cost of inspection for ...quality evaluation is high. Therefore, research for real time prediction of the weld quality is ongoing. This study is focused on studying the button diameter prediction using artificial neural network and the power data monitored during the welding. The artificial neural network model was developed as a deep neural network model, the obtained predictions using the model are compared with the actual button diameter. As a result, a coefficient of determination of 0.99 and a root mean square error of 0.06 mm are obtained from the developed model.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This study aims to reduce greenhouse gas emissions to the atmosphere and effectively utilize wasted resources by converting methane, the main component of biogas, into hydrogen. Therefore, a reactor ...was developed to decompose methane into carbon and hydrogen using solar thermal sources instead of traditional energy sources, such as coal and petroleum. The optical distributions were analyzed using TracePro, a Monte Carlo ray-tracing-based program. In addition, Fluent, a computational fluid dynamics program, was used for the heat and mass transfer, and chemical reaction. The cylindrical indirect heating reactor rotates at a constant speed to prevent damage by the heat source concentrated at the solar furnace. The inside of the reactor was filled with a porous catalyst for methane decomposition, and the outside was surrounded by insulation to reduce heat loss. The performance of the reactor, according to the cavity model, was calculated when solar heat was concentrated on the reactor surface and methane was supplied into the reactor in an environment with a solar irradiance of 700 W/m2, wind speed of 1 m/s, and outdoor temperature of 25 °C. As a result, temperature, methane mass fraction distribution, and heat loss amounts for the two cavities were obtained, and it was found that the effect on the conversion rate was largely dependent on a temperature over 1000 °C in the reactor. Moreover, the heat loss of the full-cavity model decreased by 12.5% and the methane conversion rate increased by 33.5%, compared to the semi-cavity model. In conclusion, the high-temperature environment of the reactor has a significant effect on the increase in conversion rate, with an additional effect of reducing heat loss.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The HIV-1 restriction factor SAM domain- and HD domain-containing protein 1 (SAMHD1) is proposed to inhibit HIV-1 replication by depleting the intracellular dNTP pool. However, phosphorylation of ...SAMHD1 regulates its ability to restrict HIV-1 without decreasing cellular dNTP levels, which is not consistent with a role for SAMHD1 dNTPase activity in HIV-1 restriction. Here, we show that SAMHD1 possesses RNase activity and that the RNase but not the dNTPase function is essential for HIV-1 restriction. By enzymatically characterizing Aicardi-Goutières syndrome (AGS)-associated SAMHD1 mutations and mutations in the allosteric dGTP-binding site of SAMHD1 for defects in RNase or dNTPase activity, we identify SAMHD1 point mutants that cause loss of one or both functions. The RNase-positive and dNTPase-negative SAMHD1D137N mutant is able to restrict HIV-1 infection, whereas the RNase-negative and dNTPase-positive SAMHD1Q548A mutant is defective for HIV-1 restriction. SAMHD1 associates with HIV-1 RNA and degrades it during the early phases of cell infection. SAMHD1 silencing in macrophages and CD4(+) T cells from healthy donors increases HIV-1 RNA stability, rendering the cells permissive for HIV-1 infection. Furthermore, phosphorylation of SAMHD1 at T592 negatively regulates its RNase activity in cells and impedes HIV-1 restriction. Our results reveal that the RNase activity of SAMHD1 is responsible for preventing HIV-1 infection by directly degrading the HIV-1 RNA.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Virulence of human cytomegalovirus (HCMV) clinical isolates correlates with carriage of a 15 kb segment in the UL/b′ region of the viral genome, which is absent from attenuated strains. The ...mechanisms by which this segment contributes to HCMV virulence remain obscure. We observed that intergenic RNA sequences within the 15 kb segment function as a microRNA (miRNA) decay element (miRDE) and direct the selective, sequence-specific turnover of mature miR-17 and miR-20a encoded within the host miR-17-92 cluster. Unlike canonical miRNA-mRNA interactions, the miRNA-miRDE interactions did not repress miRDE expression. miRNA binding site mutations retargeted miRDE to other miR-17-92 cluster miRNAs, which are otherwise resistant to miRDE-mediated decay. miRDE function was required to accelerate virus production in the context of lytic HCMV infection. These results indicate a role for viral noncoding RNA in regulating cellular miRNAs during HCMV pathogenesis and suggest that noncoding RNAs may play a role in mature miRNA turnover.
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•A HCMV clinical strain selectively degrades miRNAs within the host miR-17-92 cluster•A HCMV intergenic noncoding RNA in UL144-145 region, miRDE, mediates host miRNA turnover•miRDE directs miRNA turnover via sequence-specific noncanonical miRNA-mRNA interactions•miRDE is specific to virus clinical strain, and its action accelerates HCMV lytic growth
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•CFD simulation for heat loss of central tower solar receiver was carried out under various conditions.•A correlation model for estimating convection loss was derived using the simulation ...results.•The model allows of a simple heat loss calculation for various solar receivers in different conditions.
Heat loss is an important factor in predicting the performance of solar receiver of concentrated solar power (CSP) systems. This study presents a numerical simulation calculating convection and radiation heat losses from four different receiver shapes including external and cavity type receivers with different opening ratios (ratio of cavity aperture area to receiver area). The simulation was carried out using Fluent CFD (computational fluid dynamics) software considering three different receiver temperatures (600, 750, and 900°C), three wind velocities (1, 5, and 10m/s), and two wind directions (head-on and side-on). The simulation results were then used for deriving a simplified correlation model which gives the fraction of convection heat loss by a function of opening ratio, receiver temperature, and wind velocity. The calculated fraction can be easily converted to convection heat loss, total heat loss, or receiver efficiency once the radiation heat loss is estimated by any applicable prediction model. Calculated heat loses by the proposed simple correlation model showed good agreements with the simulation results with 11.4% and 5.9% average absolute deviations for convection heat loss and total heat loss, respectively. Validation of the model with experimental data was also carried out using test results available from three central receiver systems (Martin Marietta, Solar One and Solar Two).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
► One-bout aerobic exercise induces increased BDNF levels in serum and plasma and within platelets. ► Basal BDNF levels are inversely correlated with cardiorespiratory fitness levels. ► BDNF ...immediately after exercise is positively correlated with cardiorespiratory fitness. ► Cardiorespiratory fitness levels are not correlated with platelet counts.
The most current human-based studies in which brain-derived neurotrophic factor (BDNF) levels in the peripheral blood system are analyzed use it as an indicator that represents BDNF levels in the CNS. However, whether circulating BDNF (serum and plasma) is positively or inversely associated with cardiorespiratory fitness levels (VO2max) is still controversial, and no study has done to investigate exercise effects on the concentration of BDNF stored in circulating platelets which, in fact, store a large amount of circulating BDNF. Thus, the purpose of this study was to determine the relation between VO2max and all circulating BDNF levels (serum, plasma and platelets) in college male students (N=18; age, 19±1 years; height, 173.22±7.65cm; weight, 78.25±14.25kg; body fat percent, 13.82±5.68%). Dual X-ray energy absorptiometry whole body scan was used to measure their body composition. After the overnight fast, all participants were performed VO2max test, and their blood was collected at rest and immediately after the exercise. Our data resulted in significant increases in platelet counts and serum, plasma and platelet BDNF levels immediately after the exercise (p<0.01). VO2max had a significant negative correlation with serum BDNF, plasma BDNF and platelet BDNF at rest (p<0.05) but a significant positive correlation with serum, plasma BDNF, and platelet BDNF immediately after the exercise (p<0.01). However, our data show no correlation between VO2max and platelet count both at rest and immediately after the exercise. In conclusion, this is the first study showing that basal BDNF levels are inversely correlated with cardiorespiratory fitness levels but that the inverse correlations turn into positive correlations with all circulating BDNF levels immediately after the exercise. Moreover, it is the first time to provide evidence that platelet BDNF levels are also positively affected by the exercise. However, future studies will be needed to investigate what tissues provide BDNF into the circulating system and to elucidate the role of circulating BDNF.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this research, a self-reinforced composite material was manufactured using a single polyethylene material, and this self-reinforced composite material has excellent recyclability and is ...environmentally friendly compared to composite materials composed of other types of material, such as glass fiber reinforced composites (GFRP) and carbon fiber reinforced composites (CFRP). In this research, the manufactured self-reinforced composite material consists of an outer layer and an inner layer. To manufacture the outer layer, low density polyethylene (LDPE) films were laminated on high density polyethylene (HDPE) fabrics and knitted fabrics, and composite materials were prepared at various temperatures using hot stamping. A 3D printing process was utilized to manufacture the inner layer. After designing a structure with a cross-sectional shape of a triangle, circle, or hexagon, the inner layer structure was manufactured by 3D printing high-density polyethylene material. As an adhesive film for bonding the outer layer and the inner layer, a polyethylene-based self-reinforced composite material was prepared using a low-density polyethylene material. Input data for simulation of self-reinforced composite materials were obtained through tensile property analysis using a universal testing machine (UTM, Shimadzu, Kyoto, Japan), and the physical property values derived as output data and actual experimental values were obtained. As a result of the comparison, the error rate between simulation data and experimental data was 5.4% when the shape of the inner layer of self-reinforced composite material was a hexagon, 3.6% when it was a circle, and 7.8% when a triangular shape showed the highest value. Simulation in a virtual space can reduce the time and cost required for actual research and can be important data for producing high-quality products.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Krill oil (KO) shows promise as a natural marine-derived ingredient for improving skin health. This study investigated its antioxidant, anti-inflammatory, anti-wrinkle, and moisturizing effects on ...skin cells and UVB-induced skin photoaging in hairless mice. In vitro assays on HDF, HaCaT, and B16/F10 cells, as well as in vivo experiments on 60 hairless mice were conducted. A cell viability assay, diphenyl-1-picryhydrazyl (DPPH) radical scavenging activity test, elastase inhibition assay, procollagen content test, MMP-1 inhibition test, and hyaluronan production assay were used to experiment on in vitro cell models. Mice received oral KO administration (100, 200, or 400 mg/kg) once a day for 15 weeks and UVB radiation three times a week. L-Ascorbic acid (L-AA) was orally administered at 100 mg/kg once daily for 15 weeks, starting from the initial ultraviolet B (UVB) exposures. L-AA administration followed each UVB session (0.18 J/cm2) after one hour. In vitro, KO significantly countered UVB-induced oxidative stress, reduced wrinkles, and prevented skin water loss by enhancing collagen and hyaluronic synthesis. In vivo, all KO dosages showed dose-dependent inhibition of oxidative stress-induced inflammatory photoaging-related skin changes. Skin mRNA expressions for hyaluronan synthesis and collagen synthesis genes also increased dose-dependently after KO treatment. Histopathological analysis confirmed that krill oil (KO) ameliorated the damage caused by UVB-irradiated skin tissues. The results imply that KO could potentially act as a positive measure in diminishing UVB-triggered skin photoaging and address various skin issues like wrinkles and moisturization when taken as a dietary supplement.
Various technical tools have been developed to probe the functions of microRNAs (miRNAs), yet their application has been limited by low efficacy and specificity. To overcome the limitations, we used ...transcription activator-like effector nucleases (TALENs) to knock out human miRNA genes. We designed and produced a library of 540 pairs of TALENs for 274 miRNA loci, focusing on potentially important miRNAs. The knockout procedure takes only 2-4 weeks and can be applied to any cell type. As a case study, we generated knockout cells for two related miRNAs, miR-141 and miR-200c, which belong to the highly conserved miR-200 family. Interestingly, miR-141 and miR-200c, despite their overall similarity, suppress largely nonoverlapping groups of targets, thus suggesting that functional miRNA-target interaction requires strict seed-pairing. Our study illustrates the potency of TALEN technology and provides useful resources for miRNA research.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Knowledge of exchange flow and its variations is important, because it determines the distribution of salt, nutrient, pollutant, and suspended sediment in estuaries. Although exchange flow has been ...studied extensively, their variations over the spring–neap tidal cycle remain unclear. Many studies have indicated that the exchange flow is weaker during spring tides than neap tides, but others have reported that it might be stronger during spring tides. Therefore, we investigated the spring–neap variation of an exchange flow and its cause based on intensive observational data and an analytical model applied to the Sumjin River estuary (SRE), Korea. The observations revealed that exchange flow increased during the spring tide but decreased during the neap tide. The horizontal salinity gradient increased about seven times more during spring tide than during neap tide in the middle of the estuary. The analytical model implied that the exchange flow in the SRE is mainly driven by the horizontal salinity gradient. The large horizontal salinity gradient and tidal current amplitude ratio in the SRE between the spring and neap tides suggests that the horizontal pressure gradient driven by the salinity gradient overwhelms vertical mixing in driving exchange flow in the SRE.
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