Accuracy of cardiac output measurements during off-pump coronary artery bypass grafting: according to the vessel anastomosis sites

Sung Yong Park,Dae Hee Kim,Han Bum Joe,Ji Young Yoo,Jin Soo Kim,Min Kang,Yong Woo Hong 대한마취통증의학회 2012 Korean Journal of Anesthesiology Vol.62 No.5

Background: During beating heart surgery, the accuracy of cardiac output (CO) measurement techniques may be influenced by several factors. This study was conducted to analyze the clinical agreement among stat CO mode (SCO), continuous CO mode (CCO), arterial pressure waveform-based CO estimation (APCO), and transesophageal Doppler ultrasound technique (UCCO) according to the vessel anastomosis sites. Methods: This study was prospectively performed in 25 patients who would be undergoing elective OPCAB. Hemodynamic variables were recorded at the following time points: during left anterior descending (LAD) anastomosis at 1 min and 5 min; during obtuse marginal (OM) anastomosis at 1 min and 5 min: and during right coronary artery (RCA) anastomosis at 1 min and 5 min. The variables measured including the SCO, CCO, APCO, and UCCO. Results: CO measurement techniques showed different correlations according to vessel anastomosis site. However, the percent error observed was higher than the value of 30% postulated by the criteria of Critchley and Critchley during all study periods for all CO measurement techniques. Conclusions: In the beating heart procedure, SCO, CCO and APCO showed different correlations according to the vessel anastomosis sites and did not agree with UCCO. CO values from the various measurement techniques should be interpreted with caution during OPCAB. Background: During beating heart surgery, the accuracy of cardiac output (CO) measurement techniques may be influenced by several factors. This study was conducted to analyze the clinical agreement among stat CO mode (SCO), continuous CO mode (CCO), arterial pressure waveform-based CO estimation (APCO), and transesophageal Doppler ultrasound technique (UCCO) according to the vessel anastomosis sites. Methods: This study was prospectively performed in 25 patients who would be undergoing elective OPCAB. Hemodynamic variables were recorded at the following time points: during left anterior descending (LAD) anastomosis at 1 min and 5 min; during obtuse marginal (OM) anastomosis at 1 min and 5 min: and during right coronary artery (RCA) anastomosis at 1 min and 5 min. The variables measured including the SCO, CCO, APCO, and UCCO. Results: CO measurement techniques showed different correlations according to vessel anastomosis site. However, the percent error observed was higher than the value of 30% postulated by the criteria of Critchley and Critchley during all study periods for all CO measurement techniques. Conclusions: In the beating heart procedure, SCO, CCO and APCO showed different correlations according to the vessel anastomosis sites and did not agree with UCCO. CO values from the various measurement techniques should be interpreted with caution during OPCAB.

푸른길 공원의 대기 환경 특성에 관한 연구

민경우,이경석,박옥현,윤관주,김도술,박세일,정원삼,이대행,조영관,Min, Kyoung-Woo,Lee, Kyoung-Soek,Park, Ok-Hyun,Yoon, Kwan-Ju,Kim, Do-Sool,Park, Se-Il,Jeung, Won-Sam,Lee, Dae-Hang,Cho, Young-Gwan 한국환경보건학회 2015 한국환경보건학회지 Vol.41 No.3

Objectives: This study aimed to survey the characteristics of air quality and meteorological conditions in a greenway park. Methods: We measured meteorological and health related factors, including noise, particulate matter ($PM_{10}$) and selected gaseous air pollutants at three locations in a greenway park and on a general roadside as comparison. The measurements were repeated four times from April to October 2014. Results: The average air temperature in the greenway park was $20.7^{\circ}C$ which was $1-2^{\circ}C$ lower than on the general roadside. The average $PM_{10}$ concentration in the greenway park was $85.0{\mu}g/m^3$, a level 2-3 times lower than that at the roadside. The noise level at the greenway site was 4.4 dB(A)- 23.0 dB(A) lower than at the roadside. The average CO, $CO_2$, $SO_2$ and NOx concentrations in the greenway park were lower than at the roadside. The average phytoncide and anions concentrations in the greenway park were higher than at the roadside. Conclusions: The urban forest of the greenway park may have some impact on air quality and meteorological conditions.

Comparison of time and cost between conventional surgical planning and virtual surgical planning in orthognathic surgery in Korea

Park, Si-Yeon,Hwang, Dae-Seok,Song, Jae-Min,Kim, Uk-Kyu Korean Association of Maxillofacial Plastic and Re 2019 Maxillofacial Plastic Reconstructive Surgery Vol.41 No.-

Background: The purpose of this study was to measure the time of the conventional surgical planning (CSP) and virtual surgical planning (VSP) in orthognathic surgery and to compare them in terms of cost. Material and method: This is a retrospective study of the patients who underwent orthognathic surgery at the Pusan National University Dental Hospital from December 2017 to August 2018. All the patients were analyzed through both CSP and VSP, and all the surgical stents were fabricated through manual and three-dimensional (3D) printing. The predictor variables were the planning method (CSP vs. VSP) and the surgery type (group I: Le Fort I osteotomy + bilateral sagittal split osteotomy [LFI+BSSO] or group II: only bilateral sagittal split osteotomy [BSSO]), and the outcomes were the time and cost. The results were analyzed using the paired t test. Results: Thirty patients (12 females, 18 males) met the inclusion criteria, and 17 patients were excluded from the study due to missing or incomplete data. There were 20 group I patients (LFI+BSSO regardless of genioplasty) and 10 group II patients (BSSO regardless of genioplasty). The average time of CSP for group I was 385 ± 7.8 min, and that for group II was 195 ± 8.33 min. The time reduction rate of VSP compared with CSP was 62.8% in group I and 41.5% in group II. On the other hand, there was no statistically significant cost reduction. Conclusions: The time investment in VSP in this study was significantly smaller than that in CSP, and the difference was greater in group I than in group II.

Effects of hydrogen plasma treatment on SnO2:F substrates for amorphous Si thin film solar cells

Min-Seung Choi,Young-Ju Lee,Jung-Dae Kwon,Yongsoo Jeong,Ju-Yun Park,강용철,Pung Keun Song,Dong-Ho Kim 한국물리학회 2013 Current Applied Physics Vol.13 No.8

We investigated the effects of hydrogen plasma treatment on the physical and electrical properties of fluorine-doped tin oxide (FTO) films used for amorphous silicon (a-Si) thin film solar cells. A slight increase in carrier concentration by the hydrogen doping effect was observed for the FTO film exposed to the hydrogen plasma for 5 min. For further exposure to the plasma, the chemical reduction became prominent and resulted in deterioration of the electrical and optical properties of the film. XPS analysis revealed that the chemical reduction of SnO2 to Sn metallic state occurs on the surface region. It was found that the defects formed by hydrogen plasma act as recombination centers at the interface between FTO electrode and p-layer of a-Si solar cells. This phenomenon resulted in the deterioration of the cell performance. The averaged conversion efficiency (6.82%) of the cells on pristine FTO hydrogen substrate was decreased to 5.81% for the cells on FTO treated for 5 min, which is mainly attributed to the decrease in short-circuit current density.

Cutting performance of tungsten carbide tools coated with diamond thin films after etching for various times

Kim, Jong Seok,Park, Yeong Min,Bae, Mun Ki,Kim, Chi Whan,Kim, Dae Weon,Shin, Dong Chul,Kim, Tae Gyu World Scientific Publishing Company 2018 Modern physics letters. B, Condensed matter physic Vol.32 No.20

<P>In this study, diamond thin films were deposited on tungsten carbide tools using surface-wave plasma-enhanced chemical vapor deposition (SWP-CVD). To eliminate the adverse effects of cobalt on the diamond deposition process, the cobalt was removed from the surface of the tools by etching with Murakami’s reagent for various times (30, 60, and 120 min). The cutting performance of the untreated and the diamond-coated WC tools was examined by performing cutting test on carbon fiber-reinforced plastic (CFRP). The results showed that all the diamond-coated tools exhibited great improvement on the durability and wear resistance compared to the uncoated one. In addition, the diamond-coated tool lift time is found to be proportional to the etching time. An increase more than twofold has been achieved when the etch time was increased from 30 min to 120 min.</P>

대황의 항산화 효과 및 타이로시네이즈 저해 활성

김정은 ( Jung Eun Kim ),박찬하 ( Chan Ha Park ),오대석 ( Dae Seok Oh ),이승연 ( Seung Yeon Lee ),장세훈 ( Se Hun Jang ),홍지연 ( Jee Yeon Hong ),민혜진 ( Hye Jin Min ),박수아 ( Su Ah Park ),원두현 ( Doo Hyun Won ),박수남 ( Soo Nam 대한화장품학회 2011 대한화장품학회지 Vol.37 No.4

본 연구에서는 대황 추출물의 항산화 활성, 타이로시네이즈(tyrosinase) 저해 활성을 확인하였다. 대황의 50 % 에탄올 추출물, 에틸아세테이트(ethyl acetate) 분획, 아글리콘(aglycone) 분획으로 실험을 진행하였다. 대황 추출물들의 DPPH (1,1-diphenyl-2-picrylhydrazyl) 소거활성(FSC₅₀)은 대표적인 항산화제인 (+)-α-tocopherol보다 낮은 것으로 나타났다. Luminol 발광법을 이용한 Fe³⁺-EDTA/H₂O₂ 계에서 생성된 활성산소종에 대한 아글리콘 분획의 소거활성(총 항산화능, OSC₅₀)은 0.265 μg/mL로 매우 큰 활성을 나타내었다. 대황 추출물의 rose-bengal로 증감된 ¹O₂에 의한 적혈구 파괴에 대한 세포보호 효과는 모든 분획에서 농도 의존적(1∼50 μg/mL)으로 증가하였으며, 특히 아글리콘 분획은 10 μg/mL 농도에서 τ₅₀이 757.0 min으로 높은 세포 보호 활성을 나타내었다. 대황 추출물 중 아글리콘 분획의 타이로시네이즈 저해활성(IC₅₀)은 11.20 μg/mL으로 226.88 μg/mL인 알부틴(arbutin)보다 큰 활성을 보여주었다. 이상의 결과들로부터 대황 추출물은 활성산소종을 소거하는 항산화제로 이용가능하며, 특히 아글리콘 분획의 현저한 항산화 작용 및 큰 타이로시네이즈 저해 효과로부터 이들 분획 또한 화장품원료로서 응용 가능성이 큼을 알 수 있었다. In this study, the antioxidative effects and inhibitory activities on tyrosinase of Rheum undulatum (R. undulatum) L. extracts were investigated. 50 % ethanol extract, ethyl acetate and aglycone fractions of R. undulatum L. were used in experiments. The DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activities (FSC₅₀) of R. undulatum L. extracts was lower than (+)-α-tocopherol, known as a typical antioxidant. Reactive oxygen species (ROS) scavenging activities (OSC₅₀) of aglycone fraction on ROS generated in Fe³⁺-EDTA/H₂O₂ system using the luminol-dependent chemiluminescence assay showed the most prominent effect at a concentration of 0.265 μg/mL. The cellular protective effects of extract/fractions of R. undulatum L. on the rose-bengal sensitized photohemolysis of human erythrocytes were increased in a concentration dependent manner (1 ~ 50 μg/mL). Especially, aglycone fraction in 10 μg/mL concentration showed the most protective effect among extracts (τ₅₀, 757.0 min). The inhibitory effects (IC₅₀, 11.20 μg/mL) on tyrosinase of aglycone fraction was much higher than arbutin (226.88 μg/mL), known as a whitening agent. These results indicate that R. undulatum L. extracts can be used as antioxidant. Particularly, aglycone fraction of R. undulatum L. showed superior antioxdative activity and high inhibitory effect on tyrosinase. Therefore, aglycone fraction of R. undulatum L. could be applicable to new functional cosmetics.

갑상선 기능항진증 환자에서 인슐린감수성 및 인슐린분비능의 변화

최은진,강호철,이태희,정민영,이대호,장연진,박상선,조재현 대한내분비학회 1994 Endocrinology and metabolism Vol.9 No.2

The impairement of glucose metabolism is frequently associated in hyperthyroidism. The present study was performed to determine the effect of the thyroid hormone excess on insulin sensitivity and on insulin secretory function in vivo. Ten newly diagnosed hyperthyroid patients and fifteen healthy control subjects were subjected to frequently sampled intravenous glucose tolerance tests(FSIGT) after an overnight fast. Insulin sensitivity, represented by the insulin sensitivity index(S_1), was assessed by minimal model analysis of FSIGT data. Insulin secretion was measured by the total area under the insulin curve after glucose load. The results were as follows. 1) The K_G values, which represent glucose tolerance, were not different between the hyperthyroid patients and the normals(2.2+-0.3 vs. 2.5+-0.3%/min, p$gt;0.05). 2) S_1 was significantly decreased in the hyperthyroid patients in comparison to the normals(7.5+-1.4 vs. 2.6+-0.3X10^-4 min^-1/uU/ml, p$lt;0.05). 3) The basal insulin concentration was higher in the hyperthyroid patients than in the normals(8.3+-2.4 vs. 4.6+-0.4 uU/ml, p=0.07). In addition, the insulin secretory response to a glucose load was increased in the hyperthyroid patients as evidenced by the peak plasma insulin level(168.2+-30.4 vs. 89.2+-13.9 uU/ml, p$lt;0.05) and by the total area under the insulin curve(2641.1+-443.2 vs. 1696.7+-204.3 min uU/ml, p$lt;0.05). These results clearly demonstrated that insulin sensitivity was impaired in these newly diagnosed hyperthyroid patients. However, glucose tolerance was maintained by the increased insulin secretion (J Kor Soc Endocrinol 9:108-114, 1994).

간질환환자의 위내용물 배출시간에 관한 연구

함준수(Joon Soo Hahm),이동후(Dong Hoo Lee),박경남(Kyung Nam Park),이민호(Min Ho Lee),이종철(Jong Chul Rhee),기춘석(Choon Suck Kee),유대현(Dae Hyun Yoo) 대한소화기학회 1989 대한소화기학회지 Vol.21 No.2

N/A Gastric emptying time(GET) is influenced by several factors, such as neura), hormonal and composi- tion and physiochemical properties of food. The patients with delayed GET have some upper gastrointestinal symptoms such as recurrent nausea, vomiting, postprandia! Bloating, anorexia, and iveight loss. And also, almost of acute hepatitis and a part of chronic ]iver disease patients have similar symptoms of the patients with delayed GET. Therefore We performed GET measurement in liver disease patients to identify the relationship between nonspecific upper gastrointestinal symp- toms and gastric emptying function. The resu]ts are as followings; 1) Total ]iver disease patients are 28 in number, composed of acute hepatitis 3, chronic hepatitis 18, liver cirrhosis 7. 2) The GET(T1/2) of liver disease patients was delayed significantly than that of the normal volunteers. (Mean+SE;120.8+6.6 vs 89.4+5.9 mins.) 3) The GET of the symptomatic patients (N = 20 ) ivas 128.3+6.8 mins (Mean+SE), and that of the asymptomatic patients (N =8) was 101.8+13.2 mins. The symptomatic patients have delayed GET in 10 patients and asymptomatic patients have delayed GET in 3. 4) The GET of the patients who have elevated serum transaminase level higher than twice of normal is delayed significantly than that of the patients who have serum transaminase level lower than twice of normal. (Mean+SE; 143.4+2.6 vs 110.0+7.4 mins.)

Am-Be 선원을 통한 중성자의 전단면적 측정

민영기,오선영,노태익,박상태,이대원,이삼열 東亞大學校 1996 東亞論叢 Vol.33 No.-

Total cross sections was measured for 6.45MeV∼8.96MeV (average 7.7MeV) neutron on ??, ??, ?? absorber using ?? fast neutron source. The 2" ø×2" NE-213 organic liquid scitillation detector was used as a spectrometer of neutrons and gamma-rays. The zero crossing time analysis method was introduced in order to obtain the pulse heigh spectrum of neutrons and n-γ pulse-shape spectrum was investigated. The ratio of neutron peak for a Vally was 1:20. The total cross section resulting from the experiment enabled us to suppose a optical model as a neutron model, obtain the radius of a nuclei.

Cao-MgO-SiO₂-P₂O -CaF₂계 생체활성 결정화 유리의 기계적 성질에 미치는 ZrO₂및 Al₂O₃의 분산 강화 효과

박찬운,강건구,원대희,이민호,배태성 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.2

Bioactive glass-ceramics can form tight chemical bonds with bone, however, their poor mechanical properties may limit their clinical applications. Alumina ceramics show good biocompatibility and high strength but can't form chemical bonds with bone. Hydroxyapatite ceramics and bioglass form chemical bonds with bone but their strength and fracture are relatively low. Glass ceramics containing apatite and wollastonite crystals can form tight chemical bonds with bone and show relatively high strength and fracture toughness. Bioactive glass-ceramics toughened by alumina and tetragonal zirconia polycrystals show relatively high mechanical strength. Both bioactive and high strength ceramics will be widely applicable to many clinical applications. In this study, bioactive glass-ceramics toughened by alumina and zirconia polycrystals were fabricated, and crystallization behavior, biaxial flexure strength, fracture toughness, and bioactivity were measured. The results obtained were summarized as follows; 1. The major crystaline phase in the matrix glass were observed to be apatite, wollastonite, and β-TCP. 2. Biaxial flexure strength and fracture toughness values were more improved by the dispersion toughening of alumina and zirconia, and the improvement of mechanical strength was more higher in the dispersion toughening of zirconia than that of alumina. 3. The bioactivity, which was evaluted from apatite formation in the simulated body fluid, was higher in the dispersion toughening of Zr-O₂than that of Al₂O₃.