• Membrane Journal
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• v.8 no.3
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• pp.157-169
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• 1998

The effects of solvents (DMAc, NMP, 1,4-dioxane) and nonsolvents ($H_2O$, Methanol, n-hexane) on the morphology of 6FDA-p-TeMPD polyimide membrane, prepared by the wet phase inversion method, were studied. In the polymer/solvent/nonsolvent ternary system, the binodal curve, the coagulation value and the relative light transmission were measured, and the solubility parameter difference was calculated. The onset state and rate of liquid-liquid alemixing were predicted and the morphology of membrane was analyzed. It is found that the finger-like pores are formed within discontinuous polymer nodules when the binoclal curve is close to the polymer-solvent (P-S) axis, the coagulation value is small, the reduction of light transmission is easy to occur and the order of solubility parameter difference ($\Delta \delta_{i-j}$) is $\Delta \delta_{S-NS} > \Delta \delta_{P-NS} > \Delta \delta_{P-S}$. The dense skin with small nodules and the sponge type sublayer with macrovoid are formed in the case that the binodal curve is distant from the P-S axis, the onset time of liquid-liquid demixing is long and the order of $\Delta \delta_{i-j}$ is $\Delta \delta_{P-NS} >(\Delta \delta_{S-NS} < > \Delta \delta_{P-S})$. The thick layer of fine nodule coagulation and loosely grown sublayer of nodules appear when the binodal curve is distant from the P-S axis, the onset time of liquid-liquid demixing is very long and the order of $\Delta \delta_{i-j}$가 $\Delta \delta_{S-NS} > (\Delta \delta_{P-NS}$\lessgtr$ > (\Delta \delta_{P-NS} < >)\Delta \delta_{P-S}$ ).

• Journal of Trauma and Injury
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• v.20 no.2
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• pp.57-64
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• 2007

Purpose: Clinically, acute respiratory distress syndrome (ARDS) occurs within 72 hours after acute exposure of risk factors. Because of its high fatality rate once ARDS progresses, early detection and management are essential to reduce the mortality rate. Accordingly, studies on early changes of ARDS were started, and serum ferritin, as well the as injury severity score (ISS), which has been addressed in previous studies, thought to be an early predictive indicator for ARDSMethods: From March 2003 to March 2005, we investigated 50 trauma patients who were admitted to the intensive care unit in Dongguk University Medical Center, Gyeongju. The patients were characterized according to age, sex, ISS, onset of ARDS, time onset of ARDS, serum ferritin level (posttraumatic $1^{st}\;&\;2^{nd}$ day), amount of transfused blood, and death. Abdominal computed topography was performed as an early diagnostic tool to evaluate the onset of ARDS according to its diagnostic criteria. The serum ferritin was measured by using a $VIDAS^{(R)}$ Ferritin (bioMeriux, Marcy-1' Etoile, France) kit with an enzyme-linked fluorescent assay method. For statistical analysis, Windows SPSS 13.0 and MedCalc were used to confirm the probability of obtaining a predictive measure from the receiver operating characteristics (ROC) curve. Results: The ISS varied from 14 to 66 (mean: 33.8) whereas the onset of ARDS could be predicted with the score above 30 (sensitivity: 90.0%, specificity: 60.0%, p<0.05). On the posttraumatic $1^{st}$ day, the serum ferritin levels were measured to be from 31 mg/dL to 1,200 mg/dL (mean: 456 mg/dL), and the onset of ARDS could be predicted when the value was over 340 mg/dL (sensitivity: 80.0%, specificity: 65.0%, p<0.05). On the posttraumatic $2^{nd}$ day, the serum ferritin levels were measured to be from 73 mg/dL to 1,200 mg/dL (mean: 404 mg/dL), and the onset of ARDS could be predicted when the value was over 627 mg/dL (sensitivity: 60.0%, specificity: 92.5%, p<0.05). The serum ferritin levels and the ISS were significantly higher on the posttraumatic $1^{st}$ and $2^{nd}$ day in the ARDS group, suggesting that they are suitable indices predicting the onset of ARDS, however relationship between the serum ferritin levels and the ISS was not statistically significant. Conclusion: In this study, we discovered increasing serum ferritin levels in multiple- trauma patients on the posttraumatic $1^{st}$ & $2^{nd}$ day and concluded that both the serum ferritin level and the ISS were good predictors of ARDS. Although they do not show statistically significant relationship to each other, they can be used as independent predictive measures for ARDS. Since ARDS causes high mortality, further studies, including the types of surgery and the methods of anesthesia on a large number of patients are essential to predict the chance of ARDS earlier and to reduce the incidence of death.

• Journal of Oriental Neuropsychiatry
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• v.17 no.3
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• pp.21-43
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• 2006

This study was designed to assess Effects of jingansikpungtanggagam-bang on Central Nerve System. Method : jingansikpungtanggagam-bang, a Korean traditional prescription, was evaluated for its anticonvulsant effect, hypnotic activity, analgesic action, anxiolytic effect, memory enhancement, and MAO inhibitory activity and detennined the content of neurotransmitter in brain by HPLC method. Result : 1. The extract increased potently anticonvulsant effect at 1g/kg by 5.6-fold extention of onset time against control group. 2. The extract increased hvrmsis at 500mg/kg by over twofold length of sleeping time compared to control. 3. The extract showed a significant analgesic effect with 86.0% inhibition on writhing frequency at 500mg/kg by phenylquinone-induced writhing test. 4. The extract inhibited dose-dependently the activity of monoamine oxidase in vitro. 5. This prescription increased the brain levels of serotonin and 5-hydroxyindoleacetic acid by 3.3% and 1.4%, respectively. 6. the extract exhibited the anxiolytic effect with 21.3% decrease of the immobility duration against control group. 7. the extract enhanced memory recovery on scopolamine-induced impairment of passive avoidance performance at 1g/kg pretreatment with 20.2% increase of latency time. Conclusion : The result sugguest that jiugansikpungtanggagam-bang can be used effectively as a sedative prescription in Korean traditional medicine.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.201-208
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• 1995

The information obtained from the analysis of respiratory muscle elecromyographic (EMG) activities provides a mean for studying muscular activity in relation to the ventilatory process. Thus, in order to comprehend the airflow pattern and its brain control, signal processing is required to characterize respiratory muscle activity. This paper presents a computerized method for the analysis of the electrical activity of the respiratory muscles of premature lambs, and focuses upon the automatic determination of respiratory timing points such as onset and cessation points of the burst activity. Based on experimental results, reliable timing points can be obtained using the proposed methodology.

• Journal of Chest Surgery
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• v.27 no.7
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• pp.598-602
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• 1994

We have experinced 20 cases of esophageal perforation from April, 1987 to August, 1993 at ourdivision of Thoracic and Cardiovascular Surgery, Korea University, Gu Ro Hospital. Here we investgates the causes of disease, symptoms and sign, locations, time lag from onset, treatment of perforation and the results.The ratio between male and female patients was 12: 8, and age ranged from 4 years to 70 years old.The cause of esophageal perforation were instrumental trauma 7 cases, stab wound 4 cases, foreign body 4 cases, spontaneous perforations 3 cases, and others 1 cases. The middle and lower portions of esophagus was frequently involved portion in our cases [11 cases of 20].The common complications after perforation were mediastinitis [6 cases] and empyema [2 cases].The method of treatment were as follows, primary repair of perforation, simple drainge techniques including simple cervical drainage and closed thoracostomy, diversion and two-staged operations during several months. There was no mortality in our cases.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.185-190
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• 2001

The cavitation causes suction performance and efficiency of the high-speed pump to be reduced significantly To diminish these effects, the inducer has been used. Most of the inducer is designed at a maximum efficiency point of the pump, therefore suction performance drop due to effects of flow separation and inlet inverse flow is often observed at off-design point. The objective of this study is to find out the cavitation modes at various conditions by applying event detection technique and to design an inducer reducing cavitation. The pressure fluctuations at each cavitating condition were measured at inducer inlet and outlet locations using pressure transducers, which were located 90 degrees apart from each other to identify the cavitation modes. The time-frequency characteristics were analyzed by using Choi-williams distribution. In the second part of this paper, the inducer design method which uses nominal performance characteristic and onset condition of cavitation is introduced and applied to real situation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.3
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• pp.433-441
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• 2001

Natural convection of a fluid with intermediate Prand시 number of Pr=0.2 in a horizontal annulus is considered, and the bifurcation phenomena and chaotic flows are numerically investigated. The unsteady two-dimensional streamfunction-vorticity equation is solved with finite difference method. The steady downward flow with two counter-rotating eddies bifurcates to a simple periodic flow with a fundamental frequency. And afterwards, second Hopf bifurcation occurs, and a quasi-periodic flow with two incommensurable frequencies appears. However, a new time-periodic flow is established after experiencing quasi-periodic states. As Rayleigh number is increased further, the chaotic flow regime is reached after a sequence of successive Hopf bifurcation to quasi-periodic and chaotic flow regimes. A scenario similar to the Ruelle-Takens-Newhouse scenario of the onset of chaos is observed.

• Applied Microscopy
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• v.51
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• pp.16.1-16.7
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• 2021

Electron microscopy (EM) is an essential imaging method in biological sciences. Since biological specimens are exposed to radiation and vacuum conditions during EM observations, they die due to chemical bond breakage and desiccation. However, some organisms belonging to the taxa of bacteria, fungi, plants, and animals (including beetles, ticks, and tardigrades) have been reported to survive hostile scanning EM (SEM) conditions since the onset of EM. The surviving organisms were observed (i) without chemical fixation, (ii) after mounting to a precooled cold stage, (iii) using cryo-SEM, or (iv) after coating with a thin polymer layer, respectively. Combined use of these techniques may provide a better condition for preservation and live imaging of multicellular organisms for a long time beyond live-cell EM.

• Journal of Korean Neurosurgical Society
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• v.38 no.2
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• pp.116-120
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• 2005

Objective : The aim of this study is to analyze the clinical symptoms, radiological changes, interval from first operation to symptom recurrence and to propose the proper treatment method for re-operated patients following chronic subdural hematoma surgery. Methods : Between January 1992 and April 2003, 18 of 138patients of chronic subdural hematoma repeatedly underwent surgical treatment. The symptoms, mental status by Bender grade, radiological hematoma size and midline shifting, interval from symptom onset to diagnosis, surgical method and prognosis by Glasgow outcome scale[GOS] between the first attack and the recurrence were compared. Results : The symptoms at the time of recurrence were nearly the same as with the first attack, but two patients[2/18, 11.1%] showed a more declined mentality. In addition, the recurred hematoma sizes were the same or large than those previously found. Many patients were recurred within two weeks[13/18, 72.2%]. Most patients were operated on using the previous burr hole, with the exception of one patient who recurred at a different site. All patients had a good prognosis more than GOS 4 [GOS 4:4, GOS 5:12], but two died due to extracranial complication and infection. Conclusion : These results suggest that the early diagnosis and treatment are important, mostly recurred same symptoms within two weeks. Re-operation using the previous burr hole site is a good method.

• Journal of Korea Water Resources Association
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• v.49 no.6
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• pp.565-577
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• 2016

The objective of this study is to propose a method for computing the Natural Drought Index (NDI) that does not consider man-made drought facilities. Principal Component Analysis (PCA) was used to estimate the NDI. Three monthly moving cumulative runoff, soil moisture and precipitation were selected as input data of the NDI during 1977~2012. Observed precipitation data was collected from KMA ASOS (Korea Meteorological Association Automatic Synoptic Observation System), while model-driven runoff and soil moisture from Variable Infiltration Capacity Model (VIC Model) were used. Time series analysis, drought characteristic analysis and spatial analysis were used to assess the utilization of NDI and compare with existing SPI, SRI and SSI. The NDI precisely reflected onset and termination of past drought events with mean absolute error of 0.85 in time series analysis. It explained well duration and inter-arrival time with 1.3 and 1.0 respectively in drought characteristic analysis. Also, the NDI reflected regional drought condition well in spatial analysis. The accuracy rank of drought onset, termination, duration and inter-arrival time was calculated by using NDI, SPI, SRI and SSI. The result showed that NDI is more precise than the others. The NDI overcomes the limitation of univariate drought indices and can be useful for drought analysis as representative measure of different types of drought such as meteorological, hydrological and agricultural droughts.