• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.184-188
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• 2002

Unsaturated $Cr(CO)_x(1{\leq}x{\leq}5)$molecules were generated in the gas phase from photolysis of $Cr(CO)_6$vapor in He using an unfocussed weak UV laser pulse and their reactions with $O_2$ and $N_2O$ have been studied. The formation and disappearance of the ground state CrO molecules were identified by monitoring laser-induced fluorescence(LIF) intensities vs delay time between the photolysis and probe pulses. The photolysis laser power dependence as well as the delay time dependence of LIF intensities from the CrO orange system showed different behavior as those from ground state Cr atoms, suggesting that the ground state CrO molecules were generated from the reaction between $O_2/N_2O$ and photo-fragments of $Cr(CO)_6$ by one photon absorption. The depletion rate constants for the ground state CrO by $O_2$ and $N_2O$ are $5.4{\pm}0.2{\times}10^{-11}$ and $6.5{\pm}0.4{\times}10^{-12}cm^3molecule^{-1}s^{-1}$, respectively.

• 한국분말재료학회지
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• 제21권5호
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• pp.382-388
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• 2014

Fe-TiC composite powder was fabricated by high-energy milling of powder mixture of (Fe, TiC) and (FeO, $TiH_2$, C) as starting materials, respectively. The latter one was heat-treated for reaction synthesis of TiC phase after milling. Both powders were spark-plasma sintered at various temperatures of $680-1070^{\circ}C$ for 10 min. with sintering pressure of 70 MPa and the heating rate of $50^{\circ}C/min$. under vacuum of 0.133 Pa. Density and hardness of the sintered compact was investigated. Fe-TiC composite fabricated from (FeO, $TiH_2$, C) as starting materials showed better sintered properties. It seems to be resulted from ultra-fine TiC particle size and its uniform distribution in Fe-matrix compared to the simply mixed (Fe, TiC) powder.

• 한국운동역학회지
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• 제26권1호
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• pp.31-37
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• 2016

Purpose: The purpose of this study was to investigate the differences in FT (free-torque) components between non-fatigue and fatigue conditions induced by prolonged running. Methods: Fifteen healthy runners with no previous lower-extremity fractures ($22.0{\pm}2.1$ years of age) participated in this study. Ground reaction force data were collected for the right-stance phase for 10 strides of 5 and 125-min running periods at 1,000 Hz using an instrumented force platform (instrumented dual-belt treadmills, Bertec, USA) while the subjects ran on it. The running speed was set according to the preferences of the subjects, which were determined before the experiment. FT variables were calculated from the components of the moment and force output from the force platform. A repeated-measures one-way ANOVA was used to test for significant differences between the two conditions. The alpha level for all the statistical tests was 0.05. Results: The absolute FT at the peak braking force was significantly greater after 5 mins of running than after 125 mins of running-which was regarded as a fatigued state-but there were no significant differences in the absolute peak FT or impulse between the conditions. Conclusion: The FT variables in the fatigue condition during prolonged running hardly affect the tibial stress syndrome.

• 공업화학
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• 제2권2호
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• pp.155-164
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• 1991

o-자일렌 산화반응의 반응메카니즘과 촉매활성에 대한 산화바나듐의 산화상태 및 담체의 영향을 연구하였다. o-자일렌의 산화반응은 연계반응 메카니즘 및 병렬반응 메카니즘에 의해 동시에 진행되는 것으로 나타났다. 높은 산화수를 지닌 산화바나듐은 무수프탈산으로의 선택적 산화반응에 유리한 것으로 나타났고, 반면에 낮은 산화수의 경우는 무수프탈산의 CO 및 $CO_2$로의 완전 산화반응을 유발함을 알 수 있었다. 그리고 결정성 $V_2O_5$가 낮은 비결정성의 경우보다 부분 산화반응에 대한 높은 선택도를 나타내었다.

• Journal of Electrochemical Science and Technology
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• 제1권2호
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• pp.121-126
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• 2010

An amperometric ascorbic acid selective sensor utilizing the transfer reaction of proton liberated from the dissociation of ascorbic acid in aqueous solution across an elliptic micro-hole water/organic gel interface is demonstrated. This redox inactive sensing platform offers an alternative way for the detection of ascorbic acid to avoid a fouling effect which is one of the major concerns in redox based sensing systems. The detection principle is simply measuring the current change with respect to the assisted transfer of protons by a proton selective ionophore (e.g., ETH 1778) across the micro-hole interface between the water and the polyvinylchloride-2-nitrophenyloctylether gel phase. The assisted transfer reaction of protons generated from ascorbic acid across the polarized micro-hole interface was first characterized using cyclic voltammetry. An improved sensitivity for the quantitative analysis of ascorbic acid was achieved using differential pulse stripping voltammetry with a linear response ranging from 1 to $100\;{\mu}M$ concentrations of ascorbic acid. As a demonstration, the developed sensor was applied for analyzing the content of vitamin-C in different types of commercial pharmaceutical tablets and syrups, and a satisfactory recovery from these samples were also obtained.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2419-2431
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• 2023

Experiments related to Boron Neutron Capture Therapy (BNCT) accomplished at the Institute of Nuclear Techniques (INT), Budapest University of Technology and Economics (TUB) are presented. Relevant investigations are required before designing BNCT for vivo applications. Samples of relevant boron compounds (H₃BO₃, BDTPA) usually employed in BNCT were investigated with neutron beam. Channel #5 in the research reactor (100 kW) of INT-TUB provides the neutron beam. Boron samples are mounted on a carrier for neutron irradiation. The particle attenuation of several carrier materials was investigated, and the one with the lowest attenuation was selected. The effects of boron compound type, mass, and compound phase state were also investigated. To detect the emitted charged particles, a traditional ZnS(Ag) detector was employed. The neutron beam's interaction with the detector-detecting layer is investigated. Graphite (as a moderator) was employed to change the neutron beam's characteristics. The fast neutron beam was also thermalized by placing a portable fast neutron source in a paraffin container and irradiating the H₃BO₃. The obtained results suggest that the direct measurement approach appears to be insufficiently sensitive for determining the radiation dose committed by the Alpha particles from the ¹⁰B (n,α) reaction. As a result, a new approach must be used.

• The Korean Journal of Physiology and Pharmacology
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• 제20권1호
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• pp.63-67
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• 2016

Severe graft-versus-host disease (GVHD) is an often lethal complication of allogeneic hematopoietic stem cell transplantation (HSCT). The safety of clinical-grade mesenchymal stem cells (MSCs) has been validated, but mixed results have been obtained due to heterogeneity of the MSCs. In this phase I study, the safety of bone marrow-derived homogeneous clonal MSCs (cMSCs) isolated by a new subfractionation culturing method was evaluated. cMSCs were produced in a GMP facility and intravenously administered to patients who had refractory GVHD to standard treatment resulting after allogeneic HSCT for hematologic malignancies. After administration of a single dose ($1{\times}10^6cells/kg$), 11 patients were evaluated for cMSC treatment safety and efficacy. During the trial, nine patients had 85 total adverse events and the rate of serious adverse events was 27.3% (3/11 patients). The only one adverse drug reaction related to cMSC administration was grade 2 myalgia in one patient. Treatment response was observed in four patients: one with acute GVHD (partial response) and three with chronic GVHD. The other chronic patients maintained stable disease during the observation period. This study demonstrates single cMSC infusion to have an acceptable safety profile and promising efficacy, suggesting that we can proceed with the next stage of the clinical trial.

• 대한통합의학회지
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• 제7권4호
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• pp.61-69
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• 2019

Purpose : Human gingival fibroblast cell is one of the the main cell types in periodontal tissue, which they can show anti-inflammatory activity through the production of numerous lines of inflammatory mediators such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2 and interleukins. Porphyromonas gingivalis, one of the oral pathogens, has reported to play a critical role in the development of periodontal diseases. This study aimed to investigate anti-inflammatory and antioxidative activities of Gracilaria textorii ethanol extract (GTEE) in P. gingivalis derived lipopolysaccharide (LPS-PG) stimulated human gingival fibroblast (HGF)-1 cell line. Methods : In order to analyze anti-inflammatory and antioxidative activities of GTEE in HGF-1 cell line, NOS enzyme activity, expression levels of iNOS, COX-2, NAD(P)H quinone dehydrogenase (NQO)1 and their transcription factors were estimated by Griess reaction and western hybridization. Results : LPS-PG induced overexpression of iNOS and COX-2, which was significantly attenuated by GTEE treatment in a dose-dependent manner without any cytotoxicity. In addition, intracellular NOS activity was in accordance with the result of iNOS expression. Due to important role in the regulation of inflammatory responses, phosphorylated status of p65 and c-jun, each subunit of nuclear factor (NF)-κB and activator protein (AP)-1, was also dose-dependently ameliorated by GTEE treatment. One of phase II enzymes, NQO1, and its transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), were analyzed since elevated phase II enzyme expression inhibited inflammatory response, which was significantly elevated by GTEE treatment in HGF-1 cell line. Conclusion : In conclusion, GTEE mitigated LPS-PG-stimulated inflammatory responses by attenuating NF-κB and AP-1 activation as well as accelerating NQO1 and Nrf2 expression in HGF-1 cell line. These results indicate that GTEE might be utilized a promising strategy for potential anti-inflammatory agent in periodontal diseases.

• 한국운동역학회지
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• 제20권1호
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• pp.57-65
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• 2010

Korean traditional martial arts Taekkyon has a unique stepping method, Poombalbki. The purpose of this study was to investigate kinematic factors and ground reaction forces on two types of Poombalbki, one of which use knee bending and the other use chiefly hip bending. Six male taekkyoners who are the students of Y University participated in this study. Positions and velocities of CoM, the elapsed times of each phase, angles and angular velocities of low limb joints, and GRFs were analyzed for this study. The results were as follows; CoMs of whole body, trunk, and head were more posteriorly positioned in performing hip bending Poombalbki than knee bending one. Horizontal velocities of those were slower in performing hip bending Poombalbki. A player stayed more shortly within range of his opponent in performing hip bending Poombalbki. The vertical and horizontal components of GRF of forward-stepping foot were smaller in performing hip bending Poombalbki(p<.05). In conclusion hip bending is useful strategy, because A player is farther from his opponent, he stayed more shortly within range of his opponent, and the smaller weight is loaded on his front foot in performing hip bending Poombalbki than knee bending one.

• 자연과학논문집
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• 제8권1호
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• pp.61-69
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• 1995

$BaTiO_3$는 일반적으로 $BaCO_3$와 $TiO_2$의 고상반응으로 얻어지는데 BaO의 활성이 높고 이차상이 생성되므로 순수하게 합성하기가 어렵다. 순수한 $BaTiO_3$를 얻기 위해서 공침법, 가수분해법등이 연구되고 있으나 출발 원료가 비싸고 제조 공정상 문제로 고상반응으로 합성한 것과 별차이가 없다. 그래서 고상반응의 공정을 개선하는 연구가 다시 진행되고 있으며 본 연구에서도 $BaTiO_3$를 고상반응으로 합성할 때 물성에 좋지 않은 영향을 주는 이차상인 $Ba_2TiO_4$의 생성기구를 밝히고, 그것을 조절하려 했다. $BaTiO_3$의 이론조성중 Ba가 과잉인 영역에서는 $Ba_2TiO_4$가 $TiO_2$가 과잉인 영역에서는 $BaTiO_2O_5$와 $BaTiO_3O_7$이 소지의 팽창에 원인이 되었다. 환원에서 소결되는 $CeAIO_3$와 $BaTiO_3$계의 유전체는 공기중에서 $CeAIO_3$가 분해되고 이때 생성되는 $CeO_2$가 $BaTiO_3$의 전기적 물성에 큰 영향을 주었다.