• 한국식품영양과학회지
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• 제27권1호
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• pp.38-45
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• 1998

To extract insoluble proteins and to improve funtional properties of abolished proteins, an phytase producing Aspergillus sp. SM-15 was isolated from soil. The enzyme was purified and its enzymological characteristics were investigated. Phytase production reached to maximum when the wheat bran medium containing 1% mannose, 1% yeast extract, 1% (NH4)2HPO4 and 0.2% calcium chloride was cultured for 4 days. Phytase was purified 17.1 fold and specific activity was 244.32unit/mg by a sequencial process of ammonium sulfate fraction, ion exchange chromatography and gel filtrations Pruified enzyme was confirmed as a single band by the polyacrylamide gel electro-phoresis. The molecular weight of phytase was estimated to be 46,000. The optimum pH and temperature for the phytase activity were 5.5 and 5$0^{\circ}C$. The enzyme is stable in pH 4.5~5.5, 6$0^{\circ}C$. The activity of purified enzyme was inhibited by Hg2+ whereas activited by Pb2+ and Fe2+. The activity of phytase was inhibited by the treatment with iodine. The result indicate the possible involvement of histidine at active site. Km and Vmax of the puridied phytase were 37.037mM/L and 159.87umol/min, respectively.

• 센서학회지
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• 제18권6호
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• pp.441-448
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• 2009

Magnesia partially stabilized zirconia(Mg-PSZ) solid electrolytes for an improvement of thermal shock resistance, which is suitable for the measurement of oxygen activity in a molten steel, were prepared by post-thermal aging treatment. The steelmaking oxygen sensor elements were formed by an injection molding method, sintered at $1650^{\circ}C$, and then thermal aged ranged from 1250 to $1400^{\circ}C$. Sintered density and porosity were decreased as increasing the magnesia content in a zirconia-magnesia solid solution. Fractions of cubic phase to the synthesized Mg-PSZ solid electrolytes were ranged from 13.13 to 79.54.% after post-thermal aging treatment. Very dense microstructure without voids in the grains was obtained by the post-thermal aging process. Fine tetragonal phase crystallites precipitated on the cubic surface during post-thermal aging up to $1300^{\circ}C$ improve a thermal shock resistance and reappearance of electro motive force(EMF) curve.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.63-66
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• 2006

A long term deactivation study was carried out with commercial MEA provided by Hyundai Motor Co. The deactivation phenomena were observed only at high voltage region where there is no diffusion-limited reaction. A rapid deactivation was observed up to 40h owing to the sintering of Pt particles. This was followed a gradual increase in the activity up to 300 h, which is probably caused by improvement in the electrode properties in the presence of current during the reaction. After 300 h, monotonic decrease in the activity was observed owing to dissolution of Pt particles especially in the cathode. The presence oxygen is the cause of oxidation and dissolution of Pt. The dissolution rate can be somewhat retarded by generation of current, which reduces Pt ion back to Pt in the cathode.

• 폴리머
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• 제33권5호
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• pp.429-434
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• 2009

본 연구에서는 PMMA의 전기 방사 조건을 자세히 조사하였다. 즉, DMF 및 THF를 용매로 하여 최적의 혼합비 및 농도를 조사하였다. 또한, 은을 첨가했을 때 용액의 전도성 및 섬유 직경에 대해 검토하였고, 얻어진 나노섬유 부직포의 항균성을 조사하였다. 그 결과 DMF와 THF가 7:3이며 18 wt%일 때 섬유형성능이 우수하였고, 은을 1000ppm 넣어 전기방사하였을 때 섬유 직경은 100-400 nm 이었다. 투과형 전자현미경으로 관찰한 결과 은 나노입자는 섬유의 테두리에 분포되어 있었으며, 이들은 그램 양성균 및 그램 음성균에 대해 높은 항균성을 나타내었다.

• 공업화학
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• 제23권6호
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• pp.561-566
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• 2012

PtRuW/C 촉매를 Pt : Ru : W 비를 5 : 4 : 1, 2 : 1 : 1, 1 : 1 : 1, 1 : 2 : 2로 각각 합성하였다. 촉매의 조성은 EDX분석을 통해 이론값과 비슷하다는 것을 확인하였다. TEM분석과 XRD분석으로부터 3.5~5.5 nm의 균일한 입자 크기 및 결정질 분포를 가지고 있음을 확인하였다. 유효표면적, 전류밀도, 고유 활성 및 피독률과 같은 전기화학적 특성은 CO 스트리핑, 선형쓸음 전기량 측정법, 대시간 전류법 등과 같은 방법으로 분석하였다. 이러한 분석으로부터, $PtRu_2W_2/C$를 제외한 촉매는 상업촉매보다 우수한 반응성과 안정성을 가지고 있음을 확인하였다. 이 중 가장 우수한 촉매는 $Pt_5Ru_4W/C$였으며, $121.05mA{\cdot}m^{-2}$의 specific activity와 $0.01%{\cdot}s^{-1}$의 피독률을 보였다.

• Journal of Acupuncture Research
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• 제23권4호
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• pp.175-185
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• 2006

Objectives : This study was designed to investigate effects of electro-acupuncture's stimulated frequency, intensity, duration at 5736 on tile Small Intestine Motility in Rats. Methods The motor activity of small intestine in rats was evaluated by intestinal transportation rate. Changes in tile motility of ileum in vivo was measured at 10 minutes after electro-acupuncture. Various kinds of stimulus-frequency were used in this experiment: 2 Hz, 50 Hz, 100 Hz, 2 Hz-4 trains, 8 Hz groups treated with EA of the condition in S mA, 1 ms pulse duration, 30 minutes stimulated duration. Three different stimulus-intensity were used: 1, 5, 10 mA groups treated with EA of the condition in 2 Hz, 1 ms pulse duration, 30 minutes stimulated duration. Six different stimulus-duration were used: 10, 20, 30, 40, 50, 60 minutes groups treated with EA of the condition in 2 Hz, 5 mA, 1 ms pulse duration. Results : 2 and 100 Hz groups significantly increased the small intestine motility, but 50 Hz group did not induce a significant change. Besides, small intestine motility was significantly increased only in 5 mA intensity (5 times twitch). futhermore, at least 20 minutes EA treatment was necessary to increase the small intestine motility. Conclusion : Those basic data form this study can be applied to established the effective treatment of EA for gastrointestinal diseases in the clinical field.

• Korean Journal of Acupuncture
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• 제35권4호
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• pp.187-202
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• 2018

Objectives : Non-invasive transcranial electrical stimulation is one of therapeutic interventions to change in neural excitability of the cortex. Transcranial electro-acupuncture (TEA) can modulate brain functions through changes in cortical excitability as a model of non-invasive transcranial electrical stimulation. Some composites of fermented Scutellaria baicalenis (FSB) can activate intercellular signaling pathways for activation of brain-derived neurotrophic factor that is critical for formation of neural plasticity in stroke patients. This study was aimed at evaluation of combinatory treatment of TEA and FSB on behavior recovery and cortical neural excitability in rodent focal stroke model. Methods : Focal ischemic stroke was induced by photothrombotic injury to the motor cortex of adult rats. Application of TEA with 20 Hz and $200{\mu}A$ in combination with daily oral treatment of FBS was given to stroke animals for 3 weeks. Motor recovery was evaluated by rotating bean test and ladder working test. Electrical activity of cortical pyramidal neurons of stroke model was evaluated by using multi-channel extracellular recording technique and thallium autometallography. Results : Compared with control stroke group who did not receive any treatment, Combination of TEA and FSB treatment resulted in more rapid recovery of forelimb movement following focal stroke. This combination treatment also elicited increase in spontaneous firing rate of putative pyramidal neurons. Furthermore expression of metabolic marker for neural excitability was upregulated in peri-infract area under thallium autometallography. Conclusions : These results suggest that combination treatment of TEA and FSB can be a possible remedy for motor recovery in focal stroke.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.597-598
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• 2006

In this study, we used the ESD method to prepare the protein microarrays for observation the stem cell responses to pattern size, space and shapes. The ESD method allows a reduction in spot size, high efficiency of substance transfer, and high rate in fabrication as a result of ability to simultaneously deposit thousands of identical spots. Typical electro spraying conditions for the deposition of proteins were a voltage of $3{\sim}5keV$ and the humidity under 30%. The patterns of masks have a variety of shapes, spaces, and hole sizes from 10 um to $300{\mu}m$. Three kinds of proteins(collagen, fibronectin, and vitronectin dissolved in PBS) are deposited in a dry state, preserving the functional activity of proteins. Stem cells were cultured on each protein patterned sample at $37^{\circ}C$ for 1day.

• 전기화학회지
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• 제5권4호
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• pp.221-225
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• 2002

Assisted by the highly sensitive confocal microprobe Raman spectrometer and proper surface roughening procedure, the Raman investigation on the adsorption and reaction of methanol was performed on Pt-Ru electrodes with different coverages. A detailed description of the roughening process of the Pt electrodes and the underpotential deposition of the Ru was given. Reasonably good Raman signal reflecting the metal-carbon vibration and CO vibration was detected. The appearance of vibrations of the Ru oxides, together with the existence of Ru-C, Pt-C and CO bands, clearly demonstrates the participation of the bi-functional mechanism during the oxidation process of methanol on Pt-Ru electrodes. The Pt-Ru electrode was found to have a higher catalytic activity over Pt electrodes. This preliminary study shows that electrochemical Raman spectroscopy can be applied to the study of rough electrode surface.

• 대한정형도수물리치료학회지
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• 제29권2호
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• pp.49-57
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• 2023

Background: This study aims to investigate the effect of lower limb strengthening training combined with electro muscle stimulation on the quadriceps femoris muscle activity of soccer players. Methods: Thirty university soccer players were selected as study subjects and divided into a lower limb strengthening training group combined with EMS (Group I) and a general lower limb strengthening training group (Group II), and 15 subjects were randomly assigned. After receiving general soccer training, subjects in this study additionally mediated lower limb strengthening training combined with EMS and general lower limb strengthening training for 26 minutes, 3 times a week for 8 weeks. Quadriceps femoris muscle activity was analyzed before mediation. Vastus medialis, vastus lateralis, and rectus femoris were measured with maximum isometric contraction in the manual muscle test position in order to analyze leg muscle activity. The same items as above were re-measured and a between-group analysis was conducted after 8 weeks of mediation. Results: As a result of comparative analysis of lower extremity muscle activity between groups, the lower limb strengthening training group combined with EMS showed a statistically significant difference in lower extremity muscle activity compared to the general lower limb strengthening training group. Conclusion: As a result, it was found that lower limb strengthening training combined with EMS was more effective in improving quadriceps femoris muscle activity. Based on this study, we are going to provide basic data on the possibility of using EMS in the field of sports rehabilitation for soccer players.