• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.543-548
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• 2002

Nowadays since the customers of HDD's are interested in their noise levels in addition to their primary performances such as their average access time, capacity, HDD manufacturers make efforts on reducing the noise. The works to reduce noise are usually based on the measurable physical quantities such as SPL or acoustic intensity level. However, since the HDD noise is Judged by human beings, the basis of noise reduction should be human sensations. In this paper, the noise levels of various HDD's are evaluated by the human jury test to find a relationship between the physical quantities used for noise control and the human sensations of noise. Discrepancies are found in the judgments by the human beings and by the physical quantities. The loudness level, a psychoacoustic variable, is used to solve the discrepancy.

• Journal of Digital Convergence
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• v.3 no.1
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• pp.27-44
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• 2005

Nowadays, demand for human resource for the e-learning industry is rapidly increasing along with the expansion of e-learning market capacity. However. there are numerous difficulties in expansion and industrialization of e-learning due to insufficient supply of human resources to meet the demand. Therefore, the goal of this study is to present various policy directions that can supplement the supply or e-learning manpower. Overall contents of this study focus on presenting the long-term directions for fostering of human resources for e-learning industry. Among these, role of government policies for fostering of human resources for e-learning industry is being particularly emphasized because e-learning industry is still at its infant stage.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.4
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• pp.563-570
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• 2007

This study was performed to observe the antioxidative effects, antimutagenic capacity, and cytotoxic activity of the 70% ethanol extract, and fractions, of Agaricus blazei Murill mycelium, using DPPH free radical scavenging ability, the Ames test, and SRB assay, respectively. Among the fractions, ethyl acetate showed the most effective antioxidative capacity according to the $RC_{50}$(73.6 $\mu$g/mL) of the scavenging effect on the DPPH radical. The inhibition rate of both the aqueous fraction and 70% ethanol extract(200 $\mu$g/plate) toward the Salmonella typhimurium TA100 strain was 94.6%, and it was 89.4% against the mutagenesis induced by MNNG(0.4 $\mu$g/plate). In addition, an identical concentration of the 70% ethanol extract in the TA98 strain, and the ethyl acetate fraction in the TA100 strain, showed inhibition rates of 80.3% and 76.9%, respectively, the highest activities against the mutagenesis induced by 4NQO(0.15 $\mu$g/plate). The cytotoxic effects of the 70% ethanol extract and its fractions increased with increasing sample concentration against human cervical adenocarcinoma(HeLa), human hepatocellular carcinoma(Hep3B), human breast adenocarcinoma(MCF-7), human stomach adenocarcinoma(AGS), and human lung carcinoma (A549). A 1 mg/mL concentration of the ethyl acetate fraction showed cytotoxicities of 77%, 83.8%, 82.1%, 83.1%, and 92.6% against HeLa, Hep3B, MCF-7, AGS and A549, respectively.

• 대한생식의학회:학술대회논문집
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• 2000.06a
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• pp.29-35
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• 2000

The imbalance between reactive oxygen species (ROS) production and total antioxidant capacity (TAC) in seminal fluid indicates oxidative stress and is correlated with male infertility. A composite ROS-TAC score may be more strongly correlated with infertility than ROS or TAC alone. We measured ROS, TAC, and ROS-TAC scores in semen from 127 patients and 24 healthy controls. Of the patients, 56 had varicocele, eight had varicocele with prostatitis, 35 had vasectomy reversals, and 28 had Idiopathic infertility. ROS levels were higher among infertile men, especially those with varicocele with prostatitis (mean ${\pm}$ SE, 3.25 ${\pm}$ 0.89) and vasectomy reversals (2.65 ${\pm}$ 1.01). All infertility groups had significantly lower ROS-TAC scores than control. ROS-TAC score identified 80% of patients and was significantly better than ROS at identifying varicocele and idiopathic infertility. The 13 patients whose partners later achieved pregnancies had a mean ROS-TAC score of 47.7 ${\pm}$ 13.2, similar to controls but significantly higher than the 39 patients who remained infertile (35.8 ${\pm}$ 15.0; P < 0.01). ROS-TAC score is a novel measure of oxidative stress and Is superior to ROS or TAC alone in discriminating between fertile and infertile men. Infertile men with male factor or idiopathic diagnoses had significantly lower ROS-TAC scores than controls, and men with male factor diagnoses that eventually were able to initiate a successful pregnancy had significantly higher ROS-TAC scores than those who failed.

• International Journal of Stem Cells
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• v.17 no.1
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• pp.59-69
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• 2024

Human pluripotent stem cells (hPSCs) such as human embryonic stem cells (hESCs), induced pluripotent stem cells, and somatic cell nuclear transfer (SCNT)-hESCs can permanently self-renew while maintaining their capacity to differentiate into any type of somatic cells, thereby serving as an important cell source for cell therapy. However, there are persistent challenges in the application of hPSCs in clinical trials, where one of the most significant is graft rejection by the patient immune system in response to human leukocyte antigen (HLA) mismatch when transplants are obtained from an allogeneic (non-self) cell source. Homozygous SCNT-hESCs (homo-SCNT-hESCs) were used to simplify the clinical application and to reduce HLA mismatch. Here, we present a xeno-free protocol that confirms the efficient generation of neural precursor cells in hPSCs and also the differentiation of dopaminergic neurons. Additionally, there was no difference when comparing the HLA expression patterns of hESC, homo-SCNT-hESCs and hetero-SCNT-hESCs. We propose that there are no differences in the differentiation capacity and HLA expression among hPSCs that can be cultured in vitro. Thus, it is expected that homo-SCNT-hESCs will possess a wider range of applications when transplanted with neural precursor cells in the context of clinical trials.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.14-28
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• 2018

Thanks to technical improvement on the vehicle to vehicle communication and the intelligent transportation system, gradual introduction of the autonomous vehicles is expected soon in the market. The study analyzes the autonomous vehicles' impacts on the network efficiencies. In order to measure the network efficiencies, the study applies the sequential procedures that combines the microscopic and macroscopic simulations. The microscopic simulation attends to the capacity changes due to the autonomous vehicles' proportions on the roadway while the macroscopic simulation utilizes the simulation results in order to identify the network-wide improvement. As expected, the autonomous vehicles efficiently utilizes the existing capacity of the roadway than the human driving does. Particularly, the maximum capacity improvements are expected by the 190.5% on the expressway. The significant capacity change is observed when the autonomous vehicles' proportions are about 80% or more. These improvements are translated into the macroscopic model, which also yields overall network efficiency improvement by the autonomous vehicles' penetration. However, the study identifies that the market debut of the autonomous vehicles does not promise the free flow condition, which implies the possible needs of the system optimal routing scheme for the era of the autonomous vehicles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.6
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• pp.244-257
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• 2017

Traffic congestion occurs from drivers' human factors such as driver reaction time, reckless lane change, and inexperienced driving. When Automated Vehicles are introduced, human factors are excluded, resulting in increased average vehicle speed, stabilizing traffic flow, and increasing road capacity. This study analyzed traffic flow changes through traffic volume-speed-density plots, and increased road capacity due to Automated Vehicles. As a result of the analysis, when rate of automated vehicles gests higher, the traffic flow became stable. Additionally, it was analyzed that when all vehicles were automated, the road capacity increased by about 120 %. It is expected that there will be a positive expectation in terms of traffic congestion and traffic demand management due to the introduction of Automated Vehicles.

• Molecules and Cells
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• v.45 no.12
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• pp.935-949
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• 2022

Liver cancer has a high prevalence, with majority of the cases presenting as hepatocellular carcinoma (HCC). The prognosis of metastatic HCC has hardly improved over the past decade, highlighting the necessity for liver cancer research. Studies have reported the ability of the KiSS1 gene to inhibit the growth or metastasis of liver cancer, but contradictory research results are also emerging. We, therefore, sought to investigate the effects of KiSS1 on growth and migration in human HCC cells. HepG2 human HCC cells were infected with lentivirus particles containing KiSS1. The overexpression of KiSS1 resulted in an increased proliferation rate of HCC cells. Quantitative polymerase chain reaction and immunoblotting revealed increased Akt activity, and downregulation of the G1/S phase cell cycle inhibitors. A significant increase in tumor spheroid formation with upregulation of β-catenin and CD133 was also observed. KiSS1 overexpression promoted the migratory, invasive ability, and metastatic capacity of the hepatocarcinoma cell line, and these effects were associated with changes in the expressions of epithelial mesenchymal transition (EMT)- related genes such as E-cadherin, N-cadherin, and slug. KiSS1 overexpression also resulted in dramatically increased tumor growth in the xenograft mouse model, and upregulation of proliferating cell nuclear antigen (PCNA) and Ki-67 in the HCC tumors. Furthermore, KiSS1 increased the angiogenic capacity by upregulation of the vascular endothelial growth factor A (VEGF-A) and CD31. Based on these observations, we infer that KiSS1 not only induces HCC proliferation, but also increases the metastatic potential by increasing the migratory ability and angiogenic capacity.

• Journal of Veterinary Clinics
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• v.25 no.2
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• pp.73-78
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• 2008

Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist and a short-acting general anaesthetic agent for human and veterinary use. We previously reported that treatment with ketamine impairs oxidative burst activity of canine peripheral blood leukocytes. In this study, the effect of ketamine on phagocytic capacity of canine peripheral blood leukocytes was examined in vitro. Phagocytic capacity was analyzed by using a flow cytometry. Ketamine directly decreased the phagocytic capacity of peripheral blood polymorphonuclear cells (PMN) and monocytes but not total peripheral blood mononuclear cells (PBMC). In addition, the phagocytic capacity of PMN and monocytes was inhibited by the ketamine-treated PBMC but not PMN culture supernatant. These results suggest that ketamine has a direct inhibitory effect on the phagocytic capacity of canine peripheral blood phagocytes and involves the production of soluble factor(s) from canine PBMC, which may suppress the phagocytic capacity.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.93-93
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• 2002

Oxidative stress has been associated with a number of diseases in humans. Among the sources that can generate oxidative stress, it has been reported that iron can generate reactive oxygen species (ROS) with thiol. In iron overload state, increased thiol levels in plasma appeared to be associated with human mortality.(omitted)