• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.683-692
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• 2007

Recently, plastic products in air-intake parts of automotive engines have become very popular due to advantages that include reduced weight, constricted cost, and lower intake air temperature. However, flow-induced noise in air-intake parts becomes a more serious problem for plastic intake-manifolds than for conventional aluminum-made manifolds. This is due to the fact that plastic manifolds transmit more noise owing to their lower material density. Internal aerodynamic noise from an idle speed control actuator(ISA) is qualitatively analyzed by using a scaling law, which is expressed with some flow parameters such as pressure drop, maximum flow velocity, and turbulence kinetic energy. First, basic flow characteristics through ISA passage are identified with the flow predictions obtained by applying computational fluid dynamics techniques. Then, the effects on ISA passage noise of each design factors including the duct turning shape and vane geometries are assessed. Based on these results, the preliminary low noise design for the ISA passage are proposed. The current method for the prediction of internal aerodynamic noise consists of the steady CFD and the scaling laws for the noise prediction. This combination is most cost-effective, compared with other methods, and therefore is believed to be suited for the preliminary design tool in the industrial field.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1553-1564
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• 2016

Identification of novel therapeutics in glioblastoma remains crucial due to the devastating and infiltrative capacity of this malignancy. The current study was aimed to appraise effect of arsenic trioxide (ATO) in U87MG cells. The results demonstrated that ATO induced apoptosis and impeded proliferation of U87MG cells in a dose-dependent manner and also inhibited classical NF-${\kappa}B$ signaling pathway. ATO further upregulated expression of Bax as an important proapoptotic target of NF-${\kappa}B$ and also inhibited mRNA expression of survivin, c-Myc and hTERT and suppressed telomerase activity. Moreover, ATO significantly increased adhesion of U87MG cells and also diminished transcription of NF-${\kappa}B$ down-stream targets involved in cell migration and invasion, including cathepsin B, uPA, MMP-2, MMP-9 and MMP-14 and suppressed proteolytic activity of cathepsin B, MMP-2 and MMP-9, demonstrating a possible mechanism of ATO effect on a well-known signaling in glioblastoma dissemination. Taken together, here we suggest that ATO inhibits survival and invasion of U87MG cells possibly through NF-${\kappa}B$-mediated inhibition of survivin and telomerase activity and NF-${\kappa}B$-dependent suppression of cathepsin B, MMP-2 and MMP-9.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.3805-3810
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• 2015

Arsenic trioxide (ATO) has been found to exert anti-cancer activity in various human malignancies. However, the molecular mechanisms by which ATO inhibits tumorigenesis are not fully elucidated. In the current study, we explored the molecular basis of ATO-mediated tumor growth inhibition in pancreatic cancer cells. We used multiple approaches such as MTT assay, wound healing assay, Transwell invasion assay, annexin V-FITC, cell cycle analysis, RT-PCR and Western blotting to achieve our goal. We found that ATO treatment effectively caused cell growth inhibition, suppressed clonogenic potential and induced G2-M cell cycle arrest and apoptosis in pancreatic cancer cells. Moreover, we observed a significant down-regulation of Skp2 after treatment with ATO. Furthermore, we revealed that ATO regulated Skp2 downstream genes such as FOXO1 and p53. These findings demonstrate that inhibition of Skp2 could be a novel strategy for the treatment of pancreatic cancer by ATO.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.85-90
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• 2013

In this paper, 6bit SAR ADC tolerant to ionizing radiation is presented. Radiation tolerance is achieved by using the Dummy Gate Assisted (DGA) MOSFET which was proposed to suppress the leakage current induced by ionizing radiation and its comparing sample is designed with the conventional MOSFET. The designed ADC consists of binary capacitor DAC, dynamic latch comparator, and digital logic and was fabricated using a standard 0.35um CMOS process. Irradiation was performed by Co-60 gamma ray. After the irradiation, ADC designed with the conventional MOSFET did not operate properly. On the contrary, ADC designed with the DGA MOSFET showed a little parametric degradation of which DNL was increased from 0.7LSB to 2.0LSB and INL was increased from 1.8LSB to 3.2LSB. In spite of its parametric degradation, analog to digital conversion in the ADC with DGA MOSFET was found to be possible.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2581-2587
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• 2010

Nitration of tyrosine and tryptophan residues is common in cells under nitrative stress. However, physiological consequences of protein nitration are not well characterized on a molecular level due to limited availability of the 3D structures of nitrated proteins. Molecular dynamics (MD) simulation can be an alternative tool to probe the structural perturbations induced by nitration. In this study we developed molecular mechanics parameters for 3-nitrotyrosine (NIY) and 6-nitrotryptophan (NIW) that are compatible with the AMBER-99 force field. Partial atomic charges were derived by using a multi-conformational restrained electrostatic potential (RESP) methodology that included the geometry optimized structures of both $\alpha$- and $\beta$-conformers of a capped tripeptide ACE-NIY-NME or ACE-NIW-NME. Force constants for bonds and angles were adopted from the generalized AMBER force field. Torsional force constants for the proper dihedral C-C-N-O and improper dihedral C-O-N-O of the nitro group in NIY were determined by fitting the torsional energy profiles obtained from quantum mechanical (QM) geometry optimization with those from molecular mechanical (MM) energy minimization. Force field parameters obtained for NIY were transferable to NIW so that they reproduced the QM torsional energy profiles of ACE-NIW-NME accurately. Moreover, the QM optimized structures of the tripeptides containing NIY and NIW were almost identical to the corresponding structures obtained from MM energy minimization, attesting the validity of the current parameter set. Molecular dynamics simulations of thioredoxin nitrated at the single tyrosine and tryptophan yielded well-behaved trajectories suggesting that the parameters are suitable for molecular dynamics simulations of a nitrated protein.

• Journal of the Semiconductor & Display Technology
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• v.9 no.1
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• pp.41-47
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• 2010

The effects of thermal treatment on CNTs, which were coated with a-$CN_x$ thin film, were investigated and related to variations of chemical bonding and morphologies of CNTs and also properties of field emission induced by thermal treatment. CNTs were directly grown on nano-sized conical-type tungsten tips via the inductively coupled plasma-chemical vapor deposition (ICP-CVD) system, and a-$CN_x$ films were coated on the CNTs using an RF magnetron sputtering system. Thermal treatment on a-$CN_x$ coated CNT-emitters was performed using a rapid thermal annealing (RTA) system by varying temperature ($300-700^{\circ}C$). Morphologies and microstructures of a-$CN_x$/CNTs hetero-structured emitters were analyzed by FESEM and HRTEM. Chemical composition and atomic bonding structures were analyzed by EDX, Raman spectroscopy, and XPS. The field emission properties of the a-$CN_x$/CNTs hetero-structured emitters were measured using a high vacuum (below $10^{-7}$ Torr) field-emission measurement system. For characterization of emission stability, the fluctuation and degradation of the emission current were monitored in terms of operation time. The results were compared with a-$CN_x$ coated CNT-emitters that were not thermally heated as well as with the conventional non-coated CNT-emitters.

• Journal of the Korean Magnetics Society
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• v.23 no.3
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• pp.83-88
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• 2013

The soft magnetic Fe-Si-Cr flakes with the thickness of about 1 ${\mu}m$ were annealed at 500 and $700^{\circ}C$ for 1 h, and the composite sheets for electromagnetic wave noise absorber available for quasi-microwave band were fabricated by using these annealed flakes and polymer. Further the power loss characteristics of the composite sheets was investigated to clarify the annealing effect on electromagnetic wave absorption properties. The power loss decreased in the frequency range of several GHz when the annealed flakes were used as compared to the sheet using the as-milled FeSiCr alloy flakes. Moreover the sheets using annealed flakes exhibited lower value of real and imaginary part of complex permeability. These inferior electromagnetic wave absorption properties of the composite sheets using annealed alloy flakes were considered to be obtained by the enhanced eddy current effect upon annealing-induced recovery of microstructure and resulted low complex permeability.

• Journal of Ginseng Research
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• v.34 no.2
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• pp.132-137
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• 2010

Lead (Pb) is a metal that is generally considered to be toxic to the cardiovascular system. Pb-exposed animals display the evidence of increased oxidative stress and hypertension. The current study was designed to examine whether Korean red ginseng (KRG) has protective effects against Pb-induced hypertension and oxidative stress in Pb-exposed rats. Male Sprague-Dawley rats were randomly assigned to Pb exposure or control groups. KRG was administered in drinking water at a concentration of 100 mg/kg/day; the control group received plain drinking water. Animals in the Pb-exposed groups were provided with drinking water containing 100 ppm Pb acetate for 12 weeks. Blood pressure, plasma glutathione, blood Pb concentration, and hematologic data, such as red blood cell quantity, were determined. Pb poisoning was assessed by measuring the blood Pb concentration. Pb exposure (100 ppm) for 12 weeks resulted in a marked rise in systolic blood pressure and blood Pb concentration, as well as a significant reduction in plasma glutathione levels and red blood cell quantity. Other measurements, such as heart rate, body weight, and white blood cell quantity, were unchanged. Treatment with KRG significantly lowered blood pressure, raised plasma glutathione and increased red blood cell numbers in Pb-exposed animals; it also had no effect on heart rate, body weight, or white blood cell quantity. However, the elevated blood Pb concentration was not reduced by treatment with KRG (100 mg/kg). Taken together, these data indicate that treatment with KRG in Pb-exposed animals can reduce oxidative stress and lower blood pressure, suggesting that KRG might be protective against Pb-exposed hypertension and oxidative stress.

• Current Optics and Photonics
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• v.3 no.6
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• pp.555-565
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• 2019

Development of a biomarker for predicting tumor-treatment efficacy is a matter of great concern, to reduce time, medical expense, and effort in oncology therapy. In a preclinical study, we hypothesized that the blood-flow parameter based on laser speckle flowmetry (LSF) could be a potential indicator to estimate the efficacy of breast-cancer treatment. To verify this hypothesis, a 13762-MAT-B-III rat breast tumor was grown in a dorsal skinfold window chamber applied to a nude mouse, and the change in blood flow rate (BFR) - or the speckle flow index (SFI) is used together as the same meaning in this manuscript - was longitudinally monitored during tumor growth and metronomic cyclophosphamide treatment. Based on the daily LSF angiogram, several BFR parameters (baseline SFI, normalized SFI, and △rBFR) were compared to tumor size in the normal, treated, and untreated tumor groups. Despite the incomplete tumor treatment, we found that the daily changes in all BFR parameters tended to have partially positive correlation with tumor size. Moreover, we observed that the changes in baseline SFI and normalized SFI responded one day earlier than the tumor shrinkage during chemotherapy. However, daily variations in the hypercapnia-induced △rBFR lagged tumor shrinkage by one day. This study would contribute not only to evaluating tumor vascular response to treatment, but also to monitoring blood-flow-mediated diseases (in brain, skin, and retina) by using LSF in preclinical settings.

• Science of Emotion and Sensibility
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• v.16 no.4
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• pp.457-468
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• 2013

Common theories of affect underscore valence and arousal dimensions or specific emotion. However, given the role of affect in transacting social behavior, sociality may determine the subjective experience and interpersonal response to positive stimuli. The current study examined the relationships between social positive affect and perspective taking as well as positive coping. One potential moderating effect of agreeableness on these relations was also examined. In two experiments, film segments induced socially and non-socially generated positive affects. We hypothesized and found that positive affect associated with sociality would enhance perspective taking ability and positive coping, while non-social positive affect would not. Moreover, these effects varied as a function of the level of agreeableness. These findings suggest that the social/non-social dimension influenced which positive affects elicited perspective taking and positive coping, which could not be explained by differences in subjective emotional valence or arousal. Taken together, these findings have important implications, as they point toward a previously overlooked relation linking sociality to positive affect.