• The Journal of Natural Sciences
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• v.14 no.2
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• pp.93-102
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• 2004

A yeast strain SL-27 found to produce active intracellular tyrosinase inhibitor was screened from 972 kinds of yeasts. It was identified as Malassezia pachydermatis based on microbiological characteristics. The optimum pH and temperature for the growth of Malassezia pachydermatis SL-27 were pH 7.0 and $37^{\circ}C$, respectively. The optimal culture conditions for the production of tyrosinase inhibitor by Malassezia pachydermatis SL-27 were investigated. The optimal medium cimposition for tyrosinase inhibitor production was determined to be 1.0% casamino acid, 2.0% glucose, 0.1% $KH_2PO_4$, 0.05% $MgSo_{4-}7H20$ and each 0.01 of $CaCl_2$ and NaCl. Optimal initial pH and temperature for the production of tyrosinase inhibitor were pH 5.0 and $30^{\circ}C$, respectively. The maximum tyrosinase inhibitory activity of 84%/mL of cell-free extract was showed after 12 h of cultivation under the optimal culturing conditions.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.968-972
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• 2008

Ni/Ti/Al multilayer system ('/'denotes the deposition sequence) was tested for low-resistance ohmic contact formation to Al-implanted p-type 4H-SiC. Ni 30 nm / Ti 50 nm / Al 300 nm layers were sequentially deposited by e-beam evaporation on the 4H-SiC samples which were implanted with Al (norminal doping concentration = $4\times10^{19}cm^{-3}$) and then annealed at $1700^{\circ}C$ for dopant activation. Rapid thermal anneal (RTA) temperature for ohmic contact formation was varied in the range of $840\sim930^{\circ}C$. Specific contact resistances were extracted from the measured current vs. voltage (I-V) data of linear- and circular transfer length method (TLM) patterns. In constrast to Ni contact, Ni/Ti/Al contact shows perfectly linear I-V characteristics, and possesses much lower contact resistance of about $2\sim3\times10^{-4}\Omega{\cdot}cm^2$ even after low-temperature RTA at $840^{\circ}C$, which is about 2 orders of magnitude smaller than that of Ni contact. Therefore, it was shown that RTA temperature for ohmic contact formation can be lowered to at least $840^{\circ}C$ without significant compromise of contact resistance. X-ray diffraction (XRD) analysis indicated the existence of intermetallic compounds of Ni and Al as well as $NiSi_{1-x}$, but characteristic peaks of $Ti_{3}SiC_2$, a probable narrow-gap interfacial alloy responsible for low-resistance Ti/Al ohmic contact formation, were not detected. Therefore, Al in-diffusion into SiC surface region is considered to be the dominant mechanism of improvement in conduction behavior of Ni/Ti/Al contact.

• Asian Spine Journal
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• v.12 no.6
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• pp.967-972
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• 2018

Study Design: Biomechanical study. Purpose: To investigate the relative stiffness of a new posterior pelvic fixation for unstable vertical fractures of the sacrum. Overview of Literature: The reported operative fixation techniques for vertical sacral fractures include iliosacral screw, sacral bar fixations, transiliac plating, and local plate osteosynthesis. Clinical as well as biomechanical studies have demonstrated that these conventional techniques are insufficient to stabilize the vertically unstable sacral fractures. Methods: To simulate a vertically unstable fractured sacrum, 12 synthetic pelvic models were prepared. In each model, a 5-mm gap was created through the left transforaminal zone (Denis zone II). The pubic symphysis was completely separated and then stabilized using a 3.5-mm reconstruction plate. Four each of the unstable pelvic models were then fixed with two iliosacral screws, a tension band plate, or a transiliac fixation plus one iliosacral screw. The left hemipelvis of these specimens was docked to a rigid base plate and loaded on an S1 endplate by using the Zwick Roell z010 material testing machine. Then, the vertical displacement and coronal tilt of the right hemipelves and the applied force were measured. Results: The transiliac fixation plus one iliosacral screw constructions could withstand a force at 5 mm of vertical displacement greater than the two iliosacral screw constructions (p=0.012) and the tension band plate constructions (p=0.003). The tension band plate constructions could withstand a force at $5^{\circ}$ of coronal tilt less than the two iliosacral screw constructions (p=0.027) and the transiliac fixation plus one iliosacral screw constructions (p=0.049). Conclusions: This study proposes the use of transiliac fixation in addition to an iliosacral screw to stabilize vertically unstable sacral fractures. Our biomechanical data demonstrated the superiority of adding transiliac fixation to withstand vertical displacement forces.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.3
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• pp.301-306
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• 2023

Backgrounds/Aims: Postoperative delirium (POD) is a common complication that increases mortality and morbidity in older patients. This study aimed to evaluate the clinical significance of post-cholecystectomy delirium in older patients. Methods: This retrospective study included 201 patients aged > 75 years who underwent cholecystectomy for acute or chronic cholecystitis between January 2016 and December 2019. Patients were divided into the POD (n = 21) and non-POD (n = 180) groups, and their demographic features and clinical results were compared. Results: The mean patient age was 78.88 years; the female/male ratio was 44.8%/55.2%. Laparoscopic surgery was performed in 93.5% of patients. The univariate analysis showed that lower body mass index (BMI), immobilized admission status, neuropsychiatric disease history, preoperative intervention (percutaneous drainage), high C-reactive protein, hypoalbuminemia, neutrophilia, hypo-/hyperkalemia, and longer operative time were more frequently observed in the POD group. The multivariate analysis showed that lower BMI (odds ratio [OR], 2.796; p = 0.024), neuropsychiatric disease history (OR, 3.019; p = 0.049), hyperkalemia (OR, 5.972; p = 0.007), and longer operative time (OR, 1.011; p = 0.013) were significant risk factors for POD. Conclusions: POD was associated with inflammation degree, general condition, poor nutritional status, electrolyte imbalance, and stressful conditions. Recognizing risk factors requiring multidisciplinary team approaches is important to prevent and treat POD.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.94-103
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• 2021

The purpose of this study was to identify the association between regular physical activity (PA) types and metabolic syndrome (MetS) in fertile women. Data were obtained from the seventh Korea National Health and Nutrition Examination Survey (KNHANES VII-3, 2018). The sample consisted of 4,172 fertile women over 19 years of age. The data were analyzed using an independent t-test, χ2 test, and multiple logistic regression analysis for examining the association of regular PA and MetS. The prevalence of MetS in fertile women was 3.1% (n =128), and 1,972 fertile women (47.2%) practiced regular PA. Compared to the non-regular PA group, regular PA resulted in a significantly lower systolic blood pressure (p =.002), lower waist circumference (p <.001), lower fasting blood sugar (p =.007), and higher high-density lipoprotein cholesterol (p <.001). After controlling the confounding variables, multiple logistic regression showed that the regular PA group (odds ratio 0.59, 95% confidence interval 0.35-0.98, p =.040) and the regular muscle-strengthen PA group (odds ratio 0.34, 95% confidence interval 0.14-0.80, p =.013) were associated with a decreased risk of MetS. Therefore, regular PA, including muscle-strengthen PA should be considered to develop effective MetS intervention in fertile women.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.1
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• pp.516-526
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• 2015

The purpose of this study is to compare with work satisfaction, job stress and turnover intention of nurses who work in Comprehensive nursing care service ward, Anshim unit and general ward. The subjects are nurses of general ward, Anshim unit, Comprehensive nursing care service ward from two hospitals in Seoul and one hospital located in Gyeongi province. The summary of the research is as follows. Nurses in a general ward, a Comprehensive nursing care service ward and an Anshim unit don't have meaningful difference in job satisfaction(F=0.50, p=.602), job stress(F=1.12, p=.326), turnover intention.(F=0.02, p=.972). There were some statistic differences of Work satisfaction, job stress and turnover intention according to general characteristics. Henceforth it needs diverse consideration on these factors to reduce turnover intention of nurses.

• Journal of Microbiology and Biotechnology
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• v.12 no.6
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• pp.972-978
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• 2002

Streptomyces sp. AD001 is a Gram-positive soil actinomycetes secreting an uncharacterized 2,4-dichlorophenol (DCP) oxidizing enzyme, whose activity is similar to the previously known Actinomycetes lignin-peroxidase (ALiP). This extracellular peroxidase was purified from Streptomyces sp. AD001 as a single protein band on an SDS-PACE by ammonium sulfate fractionation, Q-sepharose, concanavalin A, and Bio-Gel HTP column chromatographies. The molecular mass of the purified peroxidase was determined by SDS-PAGE to be 45.2 kDa, and 49.7 kDa with MALDI-TOF-MS, respectively. The highest level of peroxidase activity was observed at pH 7.5 and $30^{\circ}C$. The amino terminal sequence of the purified peroxidase (G-E-P-E-E-G-N-V-D-G-T-L) showed no significant homologies to my known proteins, suggesting that Streptomyces sp. AD001 may secrete a novel kind of bacterial peroxidase Initial rate kinetic data of the 2,4-DCP oxidation were best modeled with a random-binding bireactant system.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.4
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• pp.432-442
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• 2010

Ammonia is a very important constituent of the atmospheric environment because it is the most dominant gaseous alkaline species present in the atmosphere. Ammonia is known to affect ecosystems at relatively low concentration. Ammonia flux from livestock facilities can be regulated by a number of environmental factors (pH, ammonium ion, temperature, wind speed, etc). The increases in wind speed above manure from 0.0 m/s to 1.0 7m/s resulted in 2.5 times increases in ammonia flux. Wind speed and ammonia flux showed 0.982. A linear relationship with a correlation coefficient (r=0.982). When manure temperature increased from $3^{\circ}C$ to $36^{\circ}C$, the manure pH decreased approximately 0.30 to 0.46. As wind speed above the manure increased from 0.0 m/s to 1.07 m/s, ammonia flux increased approximately 2.5 times. The increasing manure temperature from $3^{\circ}C$ to $10^{\circ}C$, raised ammonia flux from 2.0 to 3.6 times (2.6 times in average similarly). The increases of manure temperature from $3^{\circ}C$ to $25^{\circ}C$ increased ammonia flux from 5.7 to 12.9 times (8.5 times in average). In this study, the correlation coefficient between ammonia flux and manure temperature was found from 0.972 to 0.989. Results of our research showed that ammonium ion concentration, pH of manure and wind speed were important factors in controlling the ammonia flux from manure livestock facilities.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.173-180
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• 2014

The purpose of this study was to investigate the effect of combined exercise on injury risk factors of lower extremity during landing. Ten sports talented athletes participated in this study. Sports talented athletes participated in a combined exercise (sports talented exercise, coordination) for 16 weeks. A three-dimensional motion analysis was performed using eight infrared cameras (sampling rate of 100 Hz), one force plate, and electromyography system (sampling rate of 1000 Hz) during landing. Kinetic, and kinematics analysis including average impulsive force, angle of lower extremity, vertical stiffness, onset of muscle activation were calculated by Matlab2009a software. Paired t-test was performed at alpha=.05. The average impulsive force in landing phase was not statistically significant (t=-.748, p=.474). The hip joint angle was more decreased in post test compared to pre test (E1: t=2.682, p=.025, E2: t=5.609, p=.000, E3: t=2.538, p=.032). The knee joint (E1: t=-.343, p=.739, E2: t=1.319, p=.220, E3: t=.589, p=.570) and ankle joint (E1: t=.081, p=.937, E2: t=.784, p=.453, E3: t=.392, p=.704) angle were tended to decrease after combined exercise. The vertical stiffness was tended to decrease after combined exercise (t=1.972, p=.080). Onset of quadriceps femoris (t=.698, p=.503) and medial gastocnemius (t=1.858, p=.096) were tended to be faster than biceps femoris (t=-.333, p=.747) after combined exercise. Although thses findings were not statistically significant except on a hip joint angle, risk factors of lower extremity such as joint angle, vertical stiffness and onset of quadriceps femoris, medial gastrocnemius were positively changed after the combined exercise but an additional training for improved onset of biceps femoris would be required in the future.

• Journal of Chest Surgery
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• v.22 no.6
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• pp.980-989
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• 1989

The Hancock porcine xenograft valves had been used in Seoul National University Hospital, mainly because of their antithrombogenicity despite of the predicted failure, from March 1976 to April 1984, and a total and consecutive 163 patients were retrospectively studied for late results with the special stress on the structural failure. The hospital mortality rate [within 30 days] was 6.1 %, and the 153 early survivors were followed up for a total of 822.9 patient-years [p-y][Mean * SD 5.38 * 3.02 years]. The linealized late mortality was 1.823%/p-y. Four major complications related to the Hancock valve were: 1.822% thromboembolism/p-y; 0.729 % bleeding/p-y; 0.972% endocarditis/p-y; 3.646% overall valve failure/p-y and 2.187 % primary tissue failure [PTF]/p-y. The actuarial survival rates at 5 and 10 years were 94.90 * 1.89% and 80.58 * 5.21 %; and the probabilities of freedom from thromboembolism at 5 and 10 years were 90.93 * 2.63% and 83.35 * 7.64 9o respectively. The probabilities from PTF at 5, 10 and 12 years were 98.02 * 1.39%, 60.62 * 8.89% and 49.60 * 12.34 %. One hundred-eighteen patients [72.4%] had single MVR [age, 34.0 * 10.9 years] with the operative mortality rate of 4.2%; and 113 early survivors were followed up for a total 616.4 patient-years[5.46 * 2.96 years]. The late mortality rate was 1.460 %/p-y. The major complications were: 1.622 % thromboembolism /p-y; 0.487% bleeding/p-y; 0.649 % endocarditis/p-y; 2.920% primary valve failure/p y and 1.785% PTF/p-y. The actuarial survival rates were 97.08 * 1.67%[at 5 years] and 81.27 * 6.64%[at 10 years], and the probabilities of freedom from thromboembolism 92.44 * 2.76 %[at 5 years] and 80.89 * 11.08%[at 10 years]. The probabilities of freedom from PTF at 5 and 10 years were 98 70 * 1.29% and 65.59 * 9.78% respectively. The mean age of 11 patients of PTF was 25.7 * 8.8 years and the valve extraction period 7.16 * 1.45 years. Failure of bioprosthetic xenograft valves are reportedly known to occur earlier in young patients in an accelerated fashion. The study with two groups divided into the cumulative younger and the cumulative older patients according to the age limits of 5-year interval strongly suggested these tendency. Although PTF began to occur past postoperative 5 years and the probabilities of freedom from PTF increased as the age limits raised and the number of patients increased in the cumulative younger patients while they decreased as the age limits lowered and the number of patients increased in the cumulative older patients, the definite age limits from which the Hancock valve can be safely recommended could not be obtained. From the results, the Hancock valves are contraindicated in patients younger than 20 to 25 years and may be safely recommended in patients older than 45 years as a tentative conclusion. Further longitudinal study may define these age factors.