• Bulletin of the Korean Chemical Society
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• 제20권6호
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• pp.672-676
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• 1999

Gas-Permeable polymeric membranes containing carboxyl groups which are suitable for enzyme immobilization were investigated in order to use them as gas electrode membranes in biosensors. Carboxylated polyurethane (CPU) was synthesized via a reaciton between 2,2-bis(hydroxymethyl)propionic acid as a chain extender and prepolymers prepared from polycarprolactone(Mn=2,000) and 4,4'-diphenylmethane diisocynate. It was difficult to prepared membranes from the pure CPU because of its high elasticity and cohesion. However, transparent free-standing membranes were easily prepared from the blend solution of CPU and carboxylated poly(vinyl chloride)(CPVC) in tetrahydrofuran. Both elasticity and cohesion of the CPU/CPVC membranes were decreased with increasing the content of CPVC. DSC experiment suggests that CPU and CPVC may be well mixed. Permeability coefficients for O₂and CO₂(Po₂and Pco₂)in the membranes increased as the proportion of CPU increased. The addition of dioxtyl phthalate(DOP), a plasticizer, significantly enhanced the Po₂and Pco₂which were 4,4 and 30 barrer, respectively, in the CPU/CPVC(80/20 wt/wt) membranes containing 20% of DOP at 25℃ and 100psi. Thus this type of membranes may have a potential for the use as gas electrode membranes in biosensors.

• Asian Journal of Atmospheric Environment
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• 제6권3호
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• pp.137-146
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• 2012

Poor indoor air quality is now worldwide concern due to its adverse impacts on our health and environment. Moreover, these impacts carry a significant burden to the economy. Various technical approaches (e.g., biological, activated carbon fiber (ACF), photocatlytic oxidation (PCO), etc.) have gained popularity in controlling indoor volatile organic compounds (VOCs). This is because removing indoor VOC sources or increasing ventilation rates is often not feasible or economical. This review provides an overview of the various air purification technologies used widely to improve indoor air quality. Although most of these technologies are very useful to remove indoor VOCs, there is no single fully satisfactory method due to their diversity and presence at the low concentration. To achieve technical innovations and the development of specific testing protocols, one should possess a better knowledge on the mechanisms of substrate uptake at VOC concentrations.

• 한국항공우주학회지
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• 제45권12호
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• pp.1007-1012
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• 2017

본 연구에서는 우주 안테나 설계용 형상기억 폴리머 시편의 전개 시험을 수행하였다. Poly(cyclooctene)을 dicumyl peroxide를 이용하여 가교시켜 PCO 형상기억 폴리머를 제조하고, 이를 이용하여 지름이 120 mm인 전개형 안테나의 축소 모델을 제작하였다. 전개 성능 시험을 위하여 원형 형태의 형상기억 폴리머 시편을 반으로 접어 임시 형상을 만든 후 두 개의 히터로 형상기억 폴리머의 유리 전이 온도보다 $15^{\circ}C$ 높은 온도로 시편을 가열하였다. 먼저 시편을 수평 설치하여 전개 실험을 수행하였다. 시편의 전개 영상을 디지털 카메라를 사용하여 촬영한 후 트래커 프로그램을 이용하여 분석하였다. 중력의 효과를 최소화하기 위하여 수직 설치하여 다시 실험을 수행하였다. 두 실험의 결과를 비교하여 형상기억 폴리머 시편의 전개 성능을 고찰하였다.

• Clinical and Experimental Reproductive Medicine
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• 제50권3호
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• pp.200-205
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• 2023

Objective: Polycystic ovary (PCO), a diagnostic component of polycystic ovary syndrome (PCOS), requires either an ovarian volume (OV) criterion or a follicle number per ovary (FNPO) criterion. This study investigated the association of OV and FNPO criteria with various manifestations of PCOS. Methods: This cross-sectional study was conducted at a university hospital among 100 patients newly diagnosed with PCOS (according to the revised Rotterdam criteria). Fasting blood samples were collected to measure glucose, total testosterone (TT), luteinizing hormone (LH), follicle-stimulating hormone (FSH), lipid, insulin, and hemoglobin A1c levels. An oral glucose tolerance test was performed. Transabdominal or transvaginal ultrasound of the ovaries was done, depending on patients' marital status. All investigations were conducted in the follicular phase of the menstrual cycle. OV >10 mL and/or FNPO ≥12 indicated PCO. A homeostasis model assessment of insulin resistance (IR) value ≥2.6 indicated IR, and metabolic syndrome (MS) was defined according to the international harmonization criteria. Results: Seventy-six participants fulfilled the OV criterion, 70 fulfilled the FNPO criterion, and 89 overall had PCO. Both maximum OV and mean OV had a significant correlation with TT levels (r=0.239, p=0.017 and r=0.280, p=0.005, respectively) and the LH/FSH ratio (r=0.212, p=0.034 and r=0.200, p=0.047, respectively). Mean OV also had a significant correlation with fasting insulin levels (r=0.210, p=0.036). Multivariate binary logistic regression analysis showed that IR (odds ratio [OR], 9.429; 95% confidence interval [CI], 1.701 to 52.271; p=0.010) and MS (OR, 7.952; 95% CI, 1.821 to 34.731; p=0.006) had significant predictive associations with OV alone, even after adjustment for age and body mass index. Conclusion: OV may be more closely related to the androgenic and metabolic characteristics of PCOS than FNPO.

• 한국환경보건학회지
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• 제30권2호
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• pp.92-97
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• 2004

Three methods for VOCs emissions control in indoor air are reduction at the source, ventilation between indoor and outdoor, and removal. The best alternative should be to replace highly emitting sources with sources having low emissions, but the pertinent information on VOCs is not always available from manufactures. Other ways of improving indoor air quality are needed. It is to increase the outside fresh-air flow to dilute the pollutants, but this method would generally provide only a dilution effect without destruction in residence. An ideal alternative to existing technologies would be a chemical oxidation process able to treat large volumes of slightly contaminated air at normal temperature without additional oxidant such as ozone generator and ion generator. Photocatalytic oxidation(PCO) represents such a process. It is characterized by a surface reaction assisted by light radiation inducing the formation of superoxide, hydroperoxide anions, or hydroxyl radicals, which are powerful oxidants. In comparison with other VOCs removal methods, PCO offers several advantages. The purpose of this study was to explore the possibilities for photocatalytic purification of slightly contaminated indoor air by using visible light such as flurescent visible light(FVL). In this study, a PCO of relatively concentrated benzene using common FVL lamps was investigated as batch type and total volatile organic compounds(TVOCs) using a common FVL lamp and penetrated sun light over window. The results of this study shown the possibility of TiO$_2$ photocatalyst application in the area of indoor air quality control.

• Journal of Korean Neurosurgical Society
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• 제40권1호
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• pp.16-21
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• 2006

Objective : Young neurosurgeons need to focus on the mortality and morbidity of aneurysmal neck clipping to develop a personal experience with an initial series. Methods : Total 88 aneurysms from 75 patients who underwent neck clipping by the same operator from 2001 to 2004 were reviewed. Patients were divided into three groups : first year [Group I], second year [Group II], and third year [Group III] in each group. Location of aneurysm, age, Fisher grade, Hunter-Hess grade [H-H grade], postoperative Glasgow outcome scale [GOS], and complications related to surgical procedures were evaluated with Chi-square and logistic regression analyses. Results : Fourteen patients had complications related to surgery [18.7%]. The major causes of mortality and morbidity related to surgery were cerebral infarction, hemorrhage and brain swelling due to intraoperative rupture, brain retraction and vasospasm. Among the 4 cases of mortality were 2 patients in Group I, 1 patient in Group II and 1 patient in Group III, and location of aneurysms were 2 internal carotid artery[ICA] and 2 posterior communicating artery[PCoA] aneurysms. There were 4 morbidity and new neurological deficits in Group I, 4 in Group II and 2 in Group III. Although mortality and morbidity during the learning curve had a statistical significance in H-H grade, age [>60 years old], and aneurysm location [especially ICA aneurysm] as variables, mortality mainly occurred in ICA and PCoA aneurysms. Conclusion : Experienced supervision or endovascular approach should be considered for the treatment of ICA and PCoA aneurysms during the learning curve.

• 시큐리티연구
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• 제49호
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• pp.67-93
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• 2016

본 연구는 성공적인 국제회의로 평가받고 있는 2010년 서울 G20 정상회의, 2012년 서울 핵안보정상회의 등 국제회의 개최사례를 중심으로 의전경호체계의 현황 및 문제점을 분석하고 그 개선방안을 제시하는데 그 목적이 있다. 본 연구에서 도출한 연구결과는 다음과 같다. 첫째, 국제회의 지원법규의 정립이 필요하다. 이를 위해서는 '국제회의산업 육성에 관한 법률'에 대한 국가차원 주무부처 정립, 국제회의 지원법규의 체계에 대한 조정, 국제회의 지원조직의 일관성 유지 등이 수반되어야 한다. 둘째, 경호안전체계 관련법규 소관부처 간 이해 조정이 필요하다. 국제회의 의전경호와 밀접한 관련이 있는 경호안전체계 관련 다수 법규 간의 충돌 가능성 해소가 필요하다. 셋째, 국제회의 의전경호체계 확립을 위한 정부합동 의전편람 제작이 필요하다. 행정부, 입법부 등에 산재하여 다소 국지적이고, 일관성이 없는 의전관련 주요지침(편람)을 정부합동 의전편람 제작을 통해 국제회의 의전체계 확립을 도모해야 할 것이다. 넷째, PCO의 전문역량 배양 및 강화가 필요하다. "분야별로 PCO를 선정, 활용하여 차세대 유망 산업으로 기대되는 국제 컨벤션 대행 산업의 기반을 육성하고 해당 분야의 인력을 양성한다"는 정부 방침이 충분히 달성할 수 있도록 다양한 분야의 PCO를 발굴하여 국가 차원의 지원을 병행해야 할 것이다.

• Journal of Evidence-Based Herbal Medicine
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• 제2권2호
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• pp.17-24
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• 2009

Poria cocos has been traditionally used for the treatment of edema, scanty urine, dizziness due to retention of fluid, reduced appetite due to asthenia of spleen, loose stool, diarrhea, distraction, sudden palpitation and insomnia in East Asia. The aim of this study was to confirm whether Poria cocos wonfire whethe(PCWE) and Poria cocos ointment (PCO) have a preventive e of ter Pthe development of afire wdethe(PCWE (AD) in 2,4-Diniwhochlorobenzene (oria)-applied Balb/ wme e. Oral administration (12.5wmg/kg, 25wmg/kg) of PCWE and fire al application (O.5wmg/mouse, 1.0mg/mouse) of PCO decreased the development of AD-like skin lesions, ear swelling, spleen weight, total serum IgE. PCWE and PCO significantly also inhibited the infiltration of mast cells in the dorsal skin.

• The Korean Journal of Physiology
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• 제26권1호
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• pp.45-54
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• 1992

Effects of pH, $PCO_2$, and adenosine on the vascular contractility were investigated in the pig coronary arteries. The helical strips of isolated coronary arteries were immersed in the HEPES or $HCO_3^-/CO_2$-buffered Tyrode's solution equilibrated with 100% $O_2\;or\;95%\;O_2-5%\;CO_2\;at\;35^{\circ}C$. The contraction was recorded isometrically using a force transducer. The amplitudes of contraction induced by ACh, high $K^+$, and electrical Held stimulation (EFS) were decreased by elevating extracellular pH (pHo) and were increased by lowering pHo. A shift from $0%\;CO_2\;to\;5%\;CO_2$ at constant pHo (pH 7.4) reduced the contractions induced by ACh, high $K^+$, EFS. However the contraction induced by 100mM $K^+$ was less influenced by the change of pHo or $CO_2$. The contraction induced by ACh in $Ca^{2+}$free Tyrode's solution as well as the contraction developed by the addition of extracellular of $Ca^{2+}$ were decreased by lowering pHo and were increased by elevating pHo. High $K^+$ (25mM) induced contraction at pH 6.8 was not returned to the level of the contraction at pH 7.4 by the elevation of extracellular. calcium $[Ca^{2+}]_o$. Adenosine-induced relaxation was more significant with 5% $CO_2$ than 0% $CO_2$ in the high $K^+$-induced contraction and was more significant with low pHo than high pHo in the contraction induced by EFS. From the above results, it is suggested that $H^+$ and $CO_2$ inhibit $Ca^{2+}$ influx as well as $Ca^{2+}$ release from intracellular $Ca^{2+}$ storage sites and enhance the relaxing effect of adenosine in the pig coronary artery.

• 한국환경과학회지
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• 제16권7호
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• pp.785-791
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• 2007

The current study evaluated the technical feasibility of the application of titanium dioxide ($TiO_{2}$) photo-catalytic air cleaners for the disinfection of bioaerosols present in indoor air. The evaluation included both laboratory and field tests and the tests of hydraulic diameter (HD) and lamp type (LT). Disinfection efficiency of photocatalytic oxidation (PCO) technique was estimated by survival ratio of bacteria or fungi calculated from the number of viable cells which form colonies on the nutrient agar plates. It was suggested that the reactor coating with $TiO_{2}$ did not enhance the adsorption of bioaerosols, and that the UV irradiation has certain extent of disinfection efficiency. The disinfection efficiency increased as HD decreased, most likely due to the decrease in the light intensity since the distance of the catalyst from the light source increased when increasing the HD. It was further suggested that the mass transfer effects were not as important as the light intensity effects on the PCO disinfection efficiency of bioaerosols. Germicidal lamp was superior to the black lamp for the disinfection of airborne bacteria and fungi, which is supported by the finding that the disinfection efficiencies were higher when the germicidal lamp was used compared to the black lamp in the laboratory test. These findings, combined with operational attributes such as a low pressure drop across the reactor and ambient temperature operation, can make the PCO reactor a possible tool in the effort to improve indoor bioaerosol levels.