• Safety and Health at Work
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• v.6 no.4
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• pp.268-278
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• 2015

Background: This study aimed to assess the whole-body vibration (WBV) exposure among large blast hole drill machine operators with regard to the International Organization for Standardization (ISO) recommended threshold values and its association with machine- and rock-related factors and workers' individual characteristics. Methods: The study population included 28 drill machine operators who had worked in four opencast iron ore mines in eastern India. The study protocol comprised the following: measurements of WBV exposure [frequency weighted root mean square (RMS) acceleration ($m/s^2$)], machine-related data (manufacturer of machine, age of machine, seat height, thickness, and rest height) collected from mine management offices, measurements of rock hardness, uniaxial compressive strength and density, and workers' characteristics via face-to-face interviews. Results: More than 90% of the operators were exposed to a higher level WBV than the ISO upper limit and only 3.6% between the lower and upper limits, mainly in the vertical axis. Bivariate correlations revealed that potential predictors of total WBV exposure were: machine manufacturer (r = 0.453, p = 0.015), age of drill (r = 0.533, p = 0.003), and hardness of rock (r = 0.561, p = 0.002). The stepwise multiple regression model revealed that the potential predictors are age of operator (regression coefficient ${\beta}=-0.052$, standard error SE = 0.023), manufacturer (${\beta}=1.093$, SE = 0.227), rock hardness (${\beta}=0.045$, SE = 0.018), uniaxial compressive strength (${\beta}=0.027$, SE = 0.009), and density (${\beta}=-1.135$, SE = 0.235). Conclusion: Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

• Journal of Microbiology and Biotechnology
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• v.29 no.8
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• pp.1230-1239
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• 2019

Scutellaria baicalensis Georgi has been widely used in China for treatment of various diseases. This study investigated the effect of Scutellaria baicalensis Georgi extracts (SBE) against Coxsackievirus B3 (CVB3)-induced myocarditis in vitro and in vivo. In vitro, Hela cells and primary myocardial cells were infected with CVB3 and treated with SBE ($50-800{\mu}g/ml$) and ribavirin ($200{\mu}M$) for 48 h and then determined by CCK8 assay. Real-time PCR and western blotting assays were performed. In vivo, a myocarditis model was induced in male BALB/c mice by injecting CVB3 suspension intraperitoneally for three times, followed by treatment with SBE (400 and 200 mg/kg) and ribavirin (100 mg/kg) for 28 days. SBE ameliorated the cytotoxicity of CVB3 in Hela cells, especially at $400{\mu}g/ml$ (39.93% vs 65.67%, p < 0.05) without influencing cell growth and also significantly reduced CVB3 replication in primary myocardial cells. The levels of AKT, ERK, and p38 were increased after CVB3 infection. SBE could downregulate the expressions of AKT and p38. In vivo, the mortality rate from CVB3 reached to 66.67%, while 10.00% and 23.33% of this came after 400 and 200 mg/kg SBE treatment, respectively (p < 0.05). The CVB3 replication was obviously reduced after SBE administration from day 5. Similarly, the levels of AKT, ERK, and p38 mRNAs and proteins were increased, and SBE suppressed the expression of AKT and p38. Our study indicates that SBE is a promising potent antiviral agent against CVB3-induced myocarditis by inhibition of virus replication via depressing AKT and p38 expressions.

• Korean Journal of Agricultural Science
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• v.47 no.4
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• pp.815-827
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• 2020

The epidermal growth factor (EGF) transgenic soybean was developed and biosynthesis of human epidermal growth factor (hEGF) in soybean seeds was confirmed. Also, EGF transgenic soybean were found to contain a herbicide resistance selectable marker by introduction of phosphinothricin acetyltransferase (PAT) gene from the Streptomyces hygroscopicus. For biosafety assessment, the EGF transgenic soybean expressing the EGF biosynthesis gene EGF and herbicide resistant gene PAT was tested to determine effects on survival of Cyprinus carpio, commonly used as a model organism in ecotoxicological studies. C. carpio was fed 100% ground soybean suspension, EGF soybean or non-genetically modified (GM) counterpart soybean (Gwangan). Gene expression of EGF soybean was confirmed by PCR and ELISA to have EGF/PAT. Feeding test showed that no significant differences in cumulative immobility or abnormal response between C. carpio samples fed on EGF soybean and non-GM counterpart soybean. The 48 h-EC50 values of the EGF and non-GM soybean were 1,688 mg·L-1 (95% confidence limits: 1,585 - 1,798 mg·L-1) and 1,575 mg·L-1 (95% confidence limits: 1,433 - 1,731 mg·L-1), respectively. The soybean NOEC (no observed effect concentration) value for C. carpio was suggested to be 625 mg·L-1. We concluded that there was no significant difference in toxicity for non-target organisms (C. carpio) between the EGF soybean and non-GM counterparts.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.607-616
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• 2021

The purpose of this study is to simulate the transport of nonuniform sediment considering the hiding-exposure effect numerically. In order to calculate the transport of multi-disperse suspended sediment mixtures, the set of advection-diffusion equations for each particle class is solved. The applicability of the numerical model is examined by comparing the simulation results with experimental data. In this study, we calculate the vertical distribution of total concentration of sediment particles using two approaches: (1) by considering the mixture as represented by a single size; and (2) by combining the concentration of the sediment corresponding to several particle size classes; From the simulation results, it is shown that both approaches calculate reasonable results due to the narrow range of size distribution. Under the condition of nonuniform sediment, the critical shear stress of the sediment particle is influenced by the size-selective entrainment, i.e., hiding-exposure effect. It is shown in this study that the effect of hiding-exposure effect on the erosion rates of fine sand is negligibly small.

• Wind and Structures
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• v.35 no.1
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• pp.55-66
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• 2022

Tall buildings are often subjected to steady and unsteady forces due to external wind flows. Measurement and mitigation of these forces becomes critical to structural design in engineering applications. Over the last few decades, many approaches such as modification of the external geometry of structures have been investigated to mitigate wind-induced load. One such proven geometric modification involved the rounding of sharp corners. In this work, we systematically analyze the impact of rounded corner radii on the reducing the flow-induced loading on a square cylinder. We perform 3-Dimensional (3D) simulations for high Reynolds number flows (Re=1 × 105) which are more likely to be encountered in practical applications. An Improved Delayed Detached Eddy Simulation (IDDES) method capable of capturing flow accurately at large Reynolds numbers is employed in this study. The IDDES formulation uses a k-ω Shear Stress Transport (SST) model for near-wall modelling that prevents mesh-induced separation of the boundary layer. The effects of these corner modifications are analyzed in terms of the resulting variations in the mean and fluctuating components of the aerodynamic forces compared to a square cylinder with no geometric changes. Plots of the angular distribution of the mean and fluctuating coefficient of pressure along the square cylinder's surface illustrate the effects of corner modifications on the different parts of the cylinder. The windward corner's separation angle was observed to decrease with an increase in radius, resulting in a narrower and longer recirculation region. Furthermore, with an increase in radius, a reduction in the fluctuating lift, mean drag, and fluctuating drag coefficients has been observed.

• The Korea Journal of Herbology
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• v.28 no.1
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• pp.65-71
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• 2013

Objectives : Asthma is a chronic, complex respiratory disease, caused by airway obstruction, airway eosinophilic inflammation(AEI), and airway hyperresponsiveness(AHR). This study was conducted to determine whether oral administration of crude water extracts of Pinellia ternate Breitenbach(PTB) has an antiasthmatic potential in the treatment of asthma in mice. Methods : Asthmatic AEI and AHR were induced by systemic sensitization to ovalbumin(OVA) by intratracheal instillation with 0.1 mg/mL suspension of diesel exhaust particles(DEP) once a week for 10 weeks in BALB/c mice. Crude PTB water extracts(50 mg/kg and 200 mg/kg) were orally administered 5 times a week for 10 weeks. Cyclosporin(10 mg/kg) was administrered the same manner as a positive control. Results : Long-term treatment with crude PTB water extracts suppressed the infiltration of inflammatory cells, including eosinophils, into airways from blood. It also reduced asthmatic AEI and AHR by attenuating the increase in the levels of cytokines such as interleukin(IL)-4, IL-5 and IL-13 in bronchoalveolar lavage fluid(BALF), as well as the levels of histamine and OVA-specific IgE in blood. However, the effect of crude PTB water extracts(200 mg/kg) was not likely to be stronger than that of cyclosporin(10 mg/kg). Conclusion : These results suggest that crude PTB water extracts have inhibitory effects on AEI and AHR in a mouse model of asthma and may act as a potential Th2 cytokine antagonist, and have a therapeutic effect on allergic asthma.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.2
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• pp.136-143
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• 2022

Recent progress has been made to establish intestinal organoids for an in vitro model as a potential alternative to an in vivo system in animals. We previously reported a reliable method for the isolation of intestinal crypts from the small intestine and robust three-dimensional (3D) expansion of intestinal organoids (basal-out) in adult bovines. The present study aimed to establish next-generation intestinal organoids for practical applications in disease modeling-based host-pathogen interactions and feed efficiency measurements. In this study, we developed a rapid and convenient method for the efficient generation of intestinal organoids through the modulation of the Wnt signaling pathway and continuous apical-out intestinal organoids. Remarkably, the intestinal epithelium only takes 3-4 days to undergo CHIR (1 µM) treatment as a Wnt activator, which is much shorter than that required for spontaneous differentiation (7 days). Subsequently, we successfully established an apical-out bovine intestinal organoid culture system through suspension culture without Matrigel matrix, indicating an apical-out membrane on the surface. Collectively, these results demonstrate the efficient generation and next-generation of bovine intestinal organoids and will facilitate their potential use for various purposes, such as disease modeling, in the field of animal biotechnology.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.2
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• pp.199-206
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• 2022

A malfunction or breakdown of a manufacturing facility leads to product defects and the suspension of production lines, resulting in huge financial losses for manufacturers. Due to the spread of smart factory services, a large amount of data is being collected in factories, and AI-based research is being conducted to predict and diagnose manufacturing facility breakdowns or manufacturing site efficiency. However, because of the characteristics of manufacturing data, such as a severe class imbalance about abnormalities and ambiguous label information that distinguishes abnormalities, developing classification or anomaly detection models is highly difficult. In this paper, we present an deep learning algorithm for anomaly detection of a manufacturing facility using reconstruction loss of CNN-based model and ananlyze its performance. The algorithm detects anomalies by relying solely on normal data from the facility's manufacturing data in the exclusion of abnormal data.

• Smart Structures and Systems
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• v.31 no.1
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• pp.57-68
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• 2023

Bridge hangers, such as those in suspension and cable-stayed bridges, suffer from cumulative fatigue damage caused by dynamic loads (e.g., cyclic traffic and wind loads) in their service condition. Thus, the identification of damage to hangers is important in preserving the service life of the bridge structure. This study develops a new method for condition assessment of bridge hangers. The tension force of the bridge and the damages in the element level can be identified using the Bayesian optimization method. To improve the number of observed data, the additional mass method is combined the Bayesian optimization method. Numerical studies are presented to verify the accuracy and efficiency of the proposed method. The influence of different acquisition functions, which include expected improvement (EI), probability-of-improvement (PI), lower confidence bound (LCB), and expected improvement per second (EIPC), on the identification of damage to the bridge hanger is studied. Results show that the errors identified by the EI acquisition function are smaller than those identified by the other acquisition functions. The identification of the damage to the bridge hanger with various types of boundary conditions and different levels of measurement noise are also studied. Results show that both the severity of the damage and the tension force can be identified via the proposed method, thereby verifying the robustness of the proposed method. Compared to the genetic algorithm (GA), particle swarm optimization (PSO), and nonlinear least-square method (NLS), the Bayesian optimization (BO) performs best in identifying the structural damage and tension force.

• Advances in nano research
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• v.16 no.4
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• pp.341-352
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• 2024

This study investigates the heat and mass transfer characteristics of a MoS₂ nanoparticle suspension in ethylene glycol over a porous stretching sheet. MoS₂ nanoparticles are known for their exceptional thermal and chemical stability which makes it convenient for enhancing the energy and mass transport properties of base fluids. Ethylene glycol, a common coolant in various industrial applications is utilized as the suspending medium due to its superior heat transfer properties. The effects of variable thermal conductivity, variable mass diffusivity, thermal radiation and thermophoresis which are crucial parameters in affecting the transport phenomena of nanofluids are taken into consideration. The governing partial differential equations representing the conservation of momentum, energy, and concentration are reduced to a set of nonlinear ordinary differential equations using appropriate similarity transformations. R software and MATLAB-bvp5c are used to compute the solutions. The impact of key parameters, including the nanoparticle volume fraction, magnetic field, Prandtl number, and thermophoresis parameter on the flow, heat and mass transfer rates is systematically examined. The study reveals that the presence of MoS₂ nanoparticles curbs the friction between the fluid and the solid boundary. Moreover, the variable thermal conductivity controls the rate of heat transfer and variable mass diffusivity regulates the rate of mass transfer. The numerical and statistical results computed are mutually justified via tables. The results obtained from this investigation provide valuable insights into the design and optimization of systems involving nanofluid-based heat and mass transfer processes, such as solar collectors, chemical reactors, and heat exchangers. Furthermore, the findings contribute to a deeper understanding of stretching sheet systems, such as in manufacturing processes involving continuous casting or polymer film production. The incorporation of MoS₂-C₂H₆O₂ nanofluids can potentially optimize temperature distribution and fluid dynamics.