• 대한치과보철학회지
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• 제44권5호
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• pp.654-664
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• 2006

Statement of problem: There has been a eat interest in the use of titanium for fixed and removable prostheses in recent because of its excellent biocompatibility. However, the melting temperature and chemical reactivity of titanium necessities casting system different from those used in conventional casting. The current titanium casting systems are based on an electric-arc design for melting the metal in an argon atmosphere and its exclusive investment. Despite the new development in Ti casting system, inadequate mold filling and internal porosity are frequently observed casting defects. Purpose : The purposes of this study were to compare the castibility and reaction layer of the casting titanium under the two casting machines and their investment condition. Material and method: coping and machine-milled titanium coping according to the casting methods and the marginal configurations. The total 28 specimens were used, and these are divided into 4 groups according to 2 casting machines and 2 investments. The castings were analyzed using x-ray microanalysis and microhardness testing. The reaction layer between margin of titanium casting and the investments was observed and analyzed with scanning electron microscope. Result: 1. Castabiliy of casting titanium specimen was best in the group of centrifugal casting machine and Selevest $CB^{\circledR}$ and good that of Selevest CB and pressure differential casting machine, Rematitan plus and centrifugal casting machine, Rematitan plus and pressure differential casting machine in order. 2. There was no significanct correlation in titanium castability in respect of casting machine. However ANOVA indicated that Selevest $CB^{\circledR}$ groups had significantly better castability than Rematitan $plus^{\circledR}$ groups.(p<0.05) 3. There was a significant microhardness difference between centrifugal casting machine groups and pressure differential groups.(p<0.05) Titanium castings in centifugal groups had significantly harder than those in pressure differential groups. 4. The addition of zirconia decreased interfacial reactivity. Conclusion: above result revealed that of the castability of titanium casting specimens had little correlation in casting machines and was better in magnesia-based investment contained ZrO2 groups. However in order to practice casting titanium in clininic, its castability should be improved, also there should be more research on factor of castability so that long-span prothesis and removable partial denture metla frame may be casted completly.

• Tuberculosis and Respiratory Diseases
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• 제81권4호
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• pp.319-329
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• 2018

Background: Bronchoalveolar lavage (BAL) is a necessary procedure for diagnosis of various lung diseases. High-flow nasal cannula (HFNC) oxygen delivery was recently introduced. This study aimed to investigate the safety and effectiveness of HFNC oxygen supply during BAL procedure in patients with acute respiratory failure (ARF). Methods: Patients who underwent BAL while using HFNC at a partial pressure of oxygen in arterial blood/fraction of inspired oxygen ($PaO_2/FiO_2$; PF) ratio of 300 or below among patients who had been admitted from March 2013 to May 2017 were retrospectively investigated. Results: Thirty-three BAL procedures were confirmed. Their baseline PF ratio was $166.1{\pm}46.7$. $FiO_2$ values before, during, and after BAL were $0.45{\pm}0.12$, $0.74{\pm}0.19$, and $0.57{\pm}0.14$, respectively. Flow (L/min) values before, during, and after BAL were $26.5{\pm}20.3$, $49.0{\pm}7.2$, and $40.8{\pm}14.2$, respectively. Both $FiO_2$ and flow during and after the procedure were significantly different from those before the procedure (both p<0.001). Oxygen saturation levels before, during, and after BAL measured by pulse oximeter were $94.8{\pm}2.9$, $94.6{\pm}3.5$, and $95.2{\pm}2.8%$, respectively. There were no significant differences in oxygen saturation among the three groups. Complications of BAL procedure included transient hypoxemia, hypotension, and fever. However, there was no endotracheal intubation within 24 hours. Baseline PF ratio in "without HFNC" group was significantly higher than that in "with HFNC" group. There were no differences in complications between the two groups. Conclusion: The use of HFNC during BAL procedure in ARF patients was effective and safe. However, there were no significant differences in oxygen saturation level and complications comparing "without HFNC" group in mild ARF. More studies are needed for moderate to severe ARF patients.

• Journal of Chest Surgery
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• 제32권5호
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• pp.413-421
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• 1999

배경: 폐장의 허혈-재관류 손상은 폐이식에서 발생하는 조기 이식장기 실패의 주요 원인의 하나로 알려져 있다. 최근 갑상선 호르몬의 활성형인 삼요드티로닌 (T3)이 심장을 비롯한 여러 장기의 허혈 손상을 줄여주는 효과가 있음을 시사하는 보고가 있다. 본 연구에서는 이러한 T3의 허혈-재관류 손상에 대한 효과가 폐장의 허혈 손상에도 효과가 있을 것으로 기대하고 덱스트란을 주성분으로 하는 세포외액성 폐보존액에 T3를 추가한 새로운 폐보존액을 제조하여 그 효과를 검증하고자 하였다. 대상 및 방법: 12마리의 황견을 6마리씩 두 군으로 나누어 제 1군에서는 새로 개발한 폐보존액을 사용하고, 제 2군에서는 유로콜린스 용액을 사용하여 폐를 적출 하였다. 적출한 폐장은 각각의 보존액에 담그어 섭씨 4도에서 20시간 보관한 후, 각 군에 6마리씩 총 12례의 좌측 폐이식을 시행하였다. 이식된 좌측폐만의 기능을 관찰하기 위해서 폐이식 후 재관류를 15분시킨 후에 우측 주폐동맥과 우측 주기관지를 결찰하고, 2시간 동안 혈역학적 변수와 가스분석을 시행하고, 측정이 종료된 후 바로 희생하여 폐조직 일부를 떼어내어 조직검사와 수분 함량 및 MDA양을 측정 비교하였다. 결과: 동맥혈 산소분압은 제 1군에서 재관류 후 60분, 90분 120분에 각각 147$\pm$25 mmHg, 148$\pm$22 mmHg, 159$\pm$21 mmHg, 제 2군에서는 각각 133$\pm$26 mmHg, 132$\pm$29 mmHg, 135$\pm$30 mmHg로 제 1군에서 조금 높은 경향을 보였으나 통계적으로 유의성은 없었다. 각 시간에서의 최대 흡기압은 제 1군에서 14.0$\pm$0.5 cmH2O, 14.2$\pm$0.6 cmH2O, 15.7$\pm$0.8 cmH2O, 제 2군에서는 17.8$\pm$2.0 cmH2O, 18.0$\pm$1.9 cmH2O, 19.3$\pm$2.7 cmH2O으로 제 1군에서 조금 낮은 경향을 보였으나 통계적 유의성은 없었다. 동맥혈 이산화탄소 분압은 제 1군에서 각 시간에 27.9$\pm$2.2 mmHg, 27.7$\pm$2.4 mmHg, 28.0$\pm$3.0 mmHg, 제 2군에서는 36.8$\pm$6.0 mmHg, 43.2$\pm$8.1 mmHg, 53.1$\pm$17.4 mmHg로 제 1군에서 유의하게 낮았다 (p<0.05). 폐혈관 저항 및 조직 MDA양은 두 군간에 유의한 차이가 없었다. 폐 조직 수분 함량은 제 1군에서 유의하게 낮았고, 조직학 검사상 폐조직 손상의 정도도 제 1군에서 적었다. 결론: 이상의 결과에서 T3를 포함한 새로 개발한 폐보존액이 유로콜린스 용액과 비교하여 폐보존능이 우수함을 확인할 수 있었고, 이는 T3가 폐이식시 폐장의 효과적 보존에 유용한 역할을 함을 시사하였다.

• Journal of Chest Surgery
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• 제43권1호
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• pp.104-107
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• 2010

급성호흡부전증후군은 치료가 어렵고 치명율이 높다. 인공호흡기 치료에 반응하지 않는 중증의 경우 체외막 산화기(Extracorporeal membrane oxygenation, ECMO)가 적용되고 있다. 교통사고로 다발성 외상을 받은 21세 여자가 흉부 방사선상 양측폐에 심한 침윤 소견과 동맥혈가스 검사상 급성호흡부전증후군(Acute respiratory distress syndrome, ARDS)으로 판단되어 정맥동맥 체외산화기(Veno- arterial Extracorporeal Membrane Oxygenation, VA ECMO) 치료를 시작하였다. ECMO 적용 2일째 흉부 방사선상 폐 침윤 소견 악화되면서 동맥혈 산소 포화도(Systemic oxygen saturation, $SaO_2$)가 85% 미만으로 저하되었다. 이에 중추신경계와 폐의 산소화를 향상시키기 위해 ECMO의 유출로에 곁회로를 이용하여 우측 경정맥에 연결하여 정맥-정맥동맥 ECMO (Veno-venoarterial ECMO, V-VA ECMO)로 전환하였고 이후 동맥혈 산소 분압($PaO_2$) 65 mmHg, $SaO_2$ 94%로 향상되었다. V-VA ECMO로의 전환은 전신에 산소 공급을 늘리기 위해 고려해 볼 수 있는 방법으로 생각된다.

• 한국재료학회지
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• 제8권11호
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• pp.977-981
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• 1998

Si 기판의 온도를 200에서 $500^{\circ}C$까지 변화시켜가면서 고집저 소자의 금속배선으로 응용되고 있는 저저항의 텅스텐 박막을 플라즈마 화학증착 방법에 의해 제작하였다. 이렇게 증착된 텅스텐 박막의 비저항은 $H_2/WF_6 $ 가스의 분압비에 따라 매우 민감하게 작용하는 것을 알 수있다. 플라즈마 밀도가 $0.7W/\textrm{cm}^2$ 이하에서는 박막내에 존재하는 잔류응력이 $2.4\times10^9dyne/\textrm{cm}^2$ 이하이다. 그러나 1.8에서 $2.7W/\textrm{cm}^2$로 증가함에 따라 잔류응력은 $8.1\times10^9$에서 $1.24\times10^{10}dyne/\textrm{cm}^2$로 갑자기 증가하는데 이는 박막을 증착할 때에 플라즈마 밀도가 증가하면 이온이나 radical bombardment 의 영향 때문이다.

• 한국전기전자재료학회논문지
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• 제32권5호
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• pp.371-375
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• 2019

Developing a thin-film transistor with characteristics such as a large area, high mobility, and high reliability are key elements required for the next generation on displays. In this paper, we have investigated the research trends related to improving the reliability of oxide-semiconductor-based thin-film transistors, which are the primary focus of study in the field of optical displays. It has been reported that thermal treatment in a high-pressure oxygen atmosphere reduces the threshold voltage shift from -7.1 V to -1.9 V under NBIS. Additionally, a device with a $SiO_2/Si_3N_4$ dual-structure has a lower threshold voltage (-0.82 V) under NBIS than a single-gate-insulator-based device (-11.6 V). The dual channel structure with different oxygen partial pressures was also confirmed to have a stable threshold voltage under NBIS. These can be considered for further study to improve the NBIS problem.

• 공업화학
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• 제21권3호
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• pp.317-322
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• 2010

본 연구에서는 폴리메틸메타아크릴에이트(polymethylmethacrylate : PMMA) 표면을 친수성으로 개질하기 위하여 불소와 산소의 혼합비율을 변수로 하여 함산소불소화를 실시하였다. 함산소불소화 처리 된 PMMA 표면 및 광투과 특성을 접촉각, 표면자유에너지. X-ray 광전자 분광기(XPS), UV-Vis 분광기를 통하여 분석하였다. 함산소불소화 처리된 PMMA의 표면은 친수화 되어 물 접촉각이 $69^{\circ}$에서 $44^{\circ}$로 감소하였다. 또한 PMMA의 표면자유에너지가 $46\;mN\;m^{-1}$ 에서 $58\;mN\;m^{-1}$로 증가하였다. 이는 함산소불소화를 통한 PMMA표면에 친수성 관능기의 형성으로 기인하였다. 또한, XPS 분석 결과로부터 함산소불소화 처리 시 PMMA 표면에 O/C비율이 증가하였고, 불소 부분압이 증가할수록 친수성을 나타내는 C-OH 결합의 �t량이 6.7%에서 24.8%로 증가하는 것을 알 수 있었다. 본 함산소불소화 조건(상온, 총압 1 bar, 불소 및 산소 혼합비 5 : 5)에서는 함산소불소화가 PMMA의 광투과 특성에 영향을 주지 않으면서도 그 표면특성이 개선됨을 관찰할 수 있었다. 이 결과로부터 함산소불소화는 PMMA 표면을 친수성으로 개질하는데 효과적인 방법으로 기대된다.

• Tuberculosis and Respiratory Diseases
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• 제69권4호
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• pp.243-249
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• 2010

Background: Chronic obstructive pulmonary disease (COPD) is one of the leading causes of disability and mortality worldwide. The aim of this study was to evaluate the risk factors associated with recurrent hospital admissions for exacerbation of COPD in Korea. Methods: A retrospective study of 77 consecutive patients hospitalized for exacerbation of COPD at Pusan National University Hospital during the time period January 2005 to May 2008 was performed. The information was collected from the hospitalization period: clinical information, spirometric measures, and laboratory variables. In addition, socioeconomic characteristics, co-morbidity, anxiety, and depression were reviewed. Frequent readmission was defined as 2 or more hospitalizations in the year following discharge. Results: During the 1-year period after discharge, 42 patients (54.6%) reported one hospital admission and 35 patients (45.4%) reported 2 or more hospital readmissions. Among the 35 frequent readmission patients, 4 had more than 10 readmissions. Univariate analysis showed that a body mass index (BMI) <$18.5kg/m^2$, duration >36 months, forced expiratory volume in 1 second ($FEV_1$) <50% predicted, arterial $CO_2$ partial pressure ($PaCO_2$) >40 mm Hg, and arterial oxygen saturation ($SaO_2$) <95% at discharge were associated significantly with frequent readmissions. The multivariate analysis revealed that BMI <$18.5kg/m^2$, $PaCO_2$ >40 mm Hg at discharge were independently associated with frequent readmissions for exacerbation of COPD. Conclusion: Frequent readmissions for exacerbation of COPD were associated with low BMI and hypercapnia at discharge.

• The Korean Journal of Pain
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• 제11권2호
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• pp.220-225
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• 1998

Background: The patients of facial hyperhidrosis have been known that they had much difficulties in interpersonal relationships and social activities due to excessive hidrosis when they were in stress, hot weather, or having meals. Previous drug therapy and stellate ganglion block have only temporary effects. The surgical method, $T_1$ sympathetomy has the risk of Hornor's syndrome. For that reasons, the sympathicotomy of proximal and distal portions of $T_2$ sympathetic ganglion with electroresectoscope used in transurethral resection seemed to be appropriate procedure, and we would like to report the results of our procedure. Method: Under the general anesthesia with semi-sitting position, and the portal was made through the small incision along the upper border of the 4th rib at the crossing point of mid-axillary line. After the partial collapse of lung by insufflation of 300 to 500 ml of $CO_2$, $T_2$ sympathetic ganglion was identified and resected proximally and distally with electro-cauterization. Finally the lung was expanded by limiting flow until the airway pressure reached 30 to 40 cm$H_2O$, and the wound was closed after removal of electroresectoscope. Result: There was no postoperative complication requiring surgical interventions. The facial sweating was stopped immediately after the operation and all the patients appeared to be satisfied. Conclusion: $T_2$ sympathicotomy with TUR electroresectoscope is thought be the minimal invasive and highly successful method in the treatment of facial hyperhidrosis. But longer terms follow-up will be needed to prove this result.

• 자원리싸이클링
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• 제17권3호
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• pp.42-47
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• 2008

침출온도 $100^{\circ}C{\sim}140^{\circ}C$, 산소압력 $40psi{\sim}100psi$, NaOH농도 $0.5M{\sim}2M$ 범위의 침출조건에서 황비철광과 방연광의 혼합황화광의 알카리산화에 의한 Pb 침출실험이 수행되었다. 혼합황화광중의 방연광침출에는 침출용액중의 $OH^-$농도가 큰 영향을 미치며 낮은 $OH^-$농도의 침출용액에서는 침출반응의 진행에 따른 $OH^-$저하에 의하여 침출된 $HPbO_2^-$가 화합물로 다시 석출이 일어나서 침출율을 저하시킬 수 있다. 침출온도 $120^{\circ}C$, 산소압력 100psi, 침출시간 30분, NaOH 2M의 침출조건에서 처리한 침출잔사 중의 Pb함량이 가장 낮은 결과를 얻었다.