• Tuberculosis and Respiratory Diseases
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• v.46 no.3
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• pp.311-316
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• 1999

Background: The drug-resistant tuberculosis has recently decreased in Korea, but it is still one of the major obstacles in the treatment of pulmonary tuberculosis. Unfortunately there are no reliable ways to figure out the drug sensitivity pattern of the M. tuberculosis in the starting point of treatment. At least several months which is critical for the success of treatment have to be passed away before getting the report of drug-sensitivity test. The aim of this study was to find out the clinical and radiological parameters that make it possible to predict the drug-resistant pulmonary tuberculosis and to make a correct decision on the antituberculosis drug regimens. Method: We studied 253 pulmonary TB patients with sputum and/or bronchial washing fluid culture-positive diagnosed at the Chung-Ang University Young-San Hospital in the period of 1989-1994. The differences in the clinical and raiological variables between the drug-sensitive and the drug-resistant tuberculosis patients were evaluated. Results: In 66 out of 253 patients(26.1%), drug resistant tuberculosis to at least one antituberculosis drug were found. Patients with retreatment showed higher resistance rate than those with initial treatment(30/69, 43.5% vs 36/184, 19.5%, p<0.01). Patients with cavitary TB showed higher resistance rate than those with non-cavitary TB(24/54, 44.4% vs 42/199, 21.1%, p<0.05). Among patients with initial treatment, those with far-advanced TB showed a higher drug resistance rate than those with minimal lesion(9/23, 36.9% vs 10/82, 12.5%, p<0.05). Patients with culture positive only in the bronchial washing fluid showed lower resistance rate than those with sputum culture positive(7/63, 11.1 % vs 59/190, 31.1%, p<0.05). Conclusion: Prior treatment history for pulmonary tuberculosis, the presence of cavity & far advanced tuberculosis in the radiologic exam, sputum rather than solely bronchial washing culture positivity would be the related factors to the drug resistance. So in the patients with such characteristics, it is needed to try to find out the drug sensitivity pattern of the infecting tuberculosis organism as soon as possible.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.4
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• pp.853-860
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• 2007

In this modern era, human beings lead their life in complex environment where there are lots of parameters such as temperature, light, smell, sound, visual stimulus etc. that play important role for quality life. These parameters affect physical and mental behavior of a human being immensely. To ensure quality life the demand for quality products is always associated with human emotion and sensibility. Due to human sensibility and emotion involvement with quality life, the design stages of any kind of product must include some certain features related with emotion and sensibility. The cues for optimizing artificial environment are the physiological responses of human in that environment. The conventional approach of environmental physiology is to measure the relationship between environmental physical parameters and human psychological parameters under artificial conditions. Using that approach we tried to design an artificial environment for our daily lives and activities associated with both physiological and psychological behavior. We developed the technique to present the mock environment and software to measure and evaluate sensibility physiologically or psychologically and a simulator to measure and evaluate sensibility that can be utilized for large scale industrial production and design of environment. Simulator to measure and analyze human sensibility (SMAS) was constructed, which was utilized to estimate human sensibility and to simulate living and office environment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.3
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• pp.158-169
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• 2019

A probabilistic model that can predict the residual useful lifetime of structure is formulated by using the gamma process which is one of the stochastic processes. The formulated stochastic model can take into account both the sampling uncertainty associated with damages measured up to now and the temporal uncertainty of cumulative damage over time. A method estimating several parameters of stochastic model is additionally proposed by introducing of the least square method and the method of moments, so that the age of a structure, the operational environment, and the evolution of damage with time can be considered. Some features related to the residual useful lifetime are firstly investigated into through the sensitivity analysis on parameters under a simple setting of single damage data measured at the current age. The stochastic model are then applied to the rubble-mound breakwater straightforwardly. The parameters of gamma process can be estimated for several experimental data on the damage processes of armor rocks of rubble-mound breakwater. The expected damage levels over time, which are numerically simulated with the estimated parameters, are in very good agreement with those from the flume testing. It has been found from various numerical calculations that the probabilities exceeding the failure limit are converged to the constraint that the model must be satisfied after lasting for a long time from now. Meanwhile, the expected residual useful lifetimes evaluated from the failure probabilities are seen to be different with respect to the behavior of damage history. As the coefficient of variation of cumulative damage is becoming large, in particular, it has been shown that the expected residual useful lifetimes have significant discrepancies from those of the deterministic regression model. This is mainly due to the effect of sampling and temporal uncertainties associated with damage, by which the first time to failure tends to be widely distributed. Therefore, the stochastic model presented in this paper for predicting the residual useful lifetime of structure can properly implement the probabilistic assessment on current damage state of structure as well as take account of the temporal uncertainty of future cumulative damage.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.82-93
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• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.

• Progress in Medical Physics
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• v.23 no.2
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• pp.71-80
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• 2012

In order to verify exact dose distributions in the state-of-the-art radiation techniques, a newly designed three-dimensional dosimeter and technique has been took strongly into consideration. The main purpose of our study is to verify the optimized parameters of polymer gel as a real volumetric dosimeter in terms of the various study of MRI. We prepared a gel dosimeter by combing 8% of gelatin, 8% of MAA, and 10 mM of THPC. We used a Co-60 gamma-ray teletherapy unit and delivered doses of 0, 2, 4, 6, 8, 10, 12, and 14 Gy to each polymer gel with a solid phantom. We used a fast spin-echo pulse to acquire the characterized T2 time of MRI. The signal noise ratio (SNR) of the head & neck coil was a relatively lower sensitivity than the body coil; therefore the dose uncertainty of head & neck coil would be lower than body coil's. But the dose uncertainty and resolution of the head & neck coil were superior to the body coil in this study. The TR time between 1,500 ms and 2,000 ms showed no significant difference in the dose resolution, but TR of 1,500 ms showed less dose uncertainty. For the slice thickness of 2.5 mm, less dose uncertainty of TE times was at 4 Gy, as well, it was the lowest result over 4 Gy at TE of 12 ms. The dose uncertainty was not critical up to 6 Gy, but the best dose resolution was obtained at 20 ms up to 8 Gy. The dose resolution shows the lowest value was over 20 ms and was an excellent result in the number of excitation (NEX) of three. The NEX of two was the highest dose resolution. We concluded that the better result of slice thickness versus NEX was related to the NEX increment and thin slice thickness.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.4
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• pp.285-291
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• 2008

Purpose: Although automatic quantification software of myocardial perfusion SPECT provides highly objective and reproducible quantitative measurements, there is still some limitation in the direct use of quantitative measurements. In this study we derived parameters using normal variation of perfusion measurements, and tried to test the usefulness of these parameters. Materials and Methods: In order to calculate normal variation of perfusion measurements on myocardial perfusion SPECT, 55 patients (M:F = 28:27) of low-likelihood for coronary artery disease were enrolled and $^{201}TI$ rest/$^{99m}Tc$-MIBI stress SPECT studies were performed. Using 20-segment model, mean (m) and standard deviation (SD) of perfusion were calculated in each segment. As a myocardial viability assessment group, another 48 patients with known coronary artery disease, who underwent coronary artery bypass graft surgery (CABG) were enrolled. $^{201}TI$ rest/$^{99m}Tc$-MIBI stress / $^{201}TI$ 24-hr delayed SPECT was performed before CABG and SPECT was followed up 3 months after CABG. From the preoperative 24-hr delayed SPECT, $Q_{delay}$ (perfusion measurement), ${\Delta}_{delay}$ ($Q_{delay}$ - m) and $Z_{delay}$ (($Q_{delay}$ - m)/SD) were defined and diagnostic performances of them for myocardial viability were evaluated using area under curve (AUC) on receiver operating characteristic (ROC) curve analysis. Results: Segmental perfusion measurements showed considerable normal variations among segments. In men, the lowest segmental perfusion measurement was $51.8{\pm}6.5$ and the highest segmental perfusion was $87.0{\pm}5.9$, and they are $58.7{\pm}8.1$ and $87.3{\pm}6.0$, respectively in women. In the viability assessment $Q_{delay}$ showed AUC of 0.633, while those for ${\Delta}_{delay}$ and $Z_{delay}$ were 0.735 and 0.716, respectively. The AUCs of ${\Delta}_{delay}$ and $Z_{delay}$ were significantly higher than that of $Q_{delay}$ (p = 0.001 and 0.018, respectively). The diagnostic performance of ${\Delta}_{delay}$, which showed highest AUC, was 85% of sensitivity and 53% of specificity at the optimal cutoff of -24.7. Conclusion: On automatic quantification of myocardial perfusion SPECT, the normal variation of perfusion measurements were considerable among segments. In the viability assessment, the parameters considering normal variation showed better diagnostic performance than the direct perfusion measurement. This study suggests that consideration of normal variation is important in the analysis of measurements on quantitative myocardial perfusion SPECT.

• Tuberculosis and Respiratory Diseases
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• v.62 no.5
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• pp.389-397
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• 2007

Background B-type natriuretic peptide (BNP) has been shown to be strong mortality predictors in a wide variety of cardiovascular syndromes. Little is known about BNP in patients with acute respiratory distress syndrome (ARDS). We studied whether BNP can predict mortality in patients with ARDS. Method Echocardiographic study was done to all patients with ARDS, and we excluded patient with low ejection fraction (less than 50%) or showing any features of diastolic dysfunction. 47 patients were enrolled between December, 2003 and February, 2006. Parameters including BNP were obtained within 24h hours at the time of enrollment. Result Mean BNP concentrations and APACHE II scores differed between the survivors and nonsurvivors (BNP, $219.5{\pm}57.7pg/mL$ vs $492.3{\pm}88.8pg/mL$; p=0.013, APACHE II score, $17.4{\pm}1.6$ vs $23.1{\pm}1.3$, p=0.009, respectively). With the use of the threshold value for BNP of 585 pg/mL, the specificity for the prediction of mortality was 94%. The threshold value for APACHE II of 15.5 showed sensitivity of 87%. 'APACHE II + $11{\times}logBNP$' showed sensitivity 63%, and specificity 82%, using threshold value for 46.14. Conclusion BNP concentrations and APCHE II scores were more elevated in nonsurvivors than survivors in patients with ARDS who have normal ejection fraction. BNP can predict mortality. Further study should be done.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.271-279
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• 1984

Effects of temperature and additives on the stability of actomyosin extracted from skeletal muscle of Israeli carp, Cyprinus carpio nudus, were studied by analyzing free SH-group, ATP-sensitivity and Ca-ATPase activity. The used additives were sucrose, sorbitol, Na-glutamate and L-cysteine. Furthermore, the denaturation constant($K_D$), protective effect(${\Delta}E/M$) and the other thermo-dynamic parameters on protein denaturation are systematically discussed. The actomyosin showed $4.12{\sim}4.68 mg/ml$ in protein concentration, $2.63{\sim}2.93\%$ in ribonucleic acid to the protein, $1:2.20{\sim}2.63$ in the binding ratio of myosin and actin, $4.33{\sim}5.26\%$ in fat content, 109.78 in ATP-sonsitivity, $0.159{\sim}0.201\;{\mu}M-Pi/min/mg-protein$ in Ca-ATPase activity and $3.3{\sim}3.4M/10^5$g-protein in free SH-group content. The first-order rate plots were obtained on the decrease of Ca-ATPase activity and ATP-sensitivity with an increase in temperature, while the free SH-group was increased to $60^{\circ}C$ and decreased rapidly above the temperature. The half-life of Ca-ATPase activity on the actomyosin Ca-ATPase was 280 min at $12^{\circ}C$, 125 min at $20^{\circ}C$, 55 min at $30^{\circ}C$ and 13 min at $40^{\circ}C$, and activation energy, activation enthalpy, activation entropy and free energy of the proteins at $20^{\circ}C$ wene 5,395 cal/mole, 4,814 cal/mole, -40.42 e.u. and 17,626 cal/mole, respectively. The protective effect of the additives on the actomyosin Ca-ATPase showed that the most effective material is $3\%$ sorbitol and followed in the order of $8\%$ Na-glutamate, $1\%$ sucrose and $1\%$ L-cysteine. The actomyosin was more stable at $-30^{\circ}C$ than at $0^{\circ}C$ and $-20^{\circ}C$. and when the additives were used in the low temperature storage, $8\%$ Na-glutamate was the most effective. $3\%$ sorbitol, $1\%$ sucrose and $1\%$ L-cysteine was to become lower in the order.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.4
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• pp.325-334
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• 2008

The standard prestressed concrete I-girder bridge (PSC I-girder bridge) is one of the most prevalent types for small and medium bridges in Korea. When determining the member forces in a section to assess the safety of girder in this type of bridge, the general practice is to use the simplified practical equations or the live load distribution factors proposed in design standards rather than the precise analysis through the finite element method or so. Meanwhile, the live load distribution factors currently used in Korean design practice are just a reflection of overseas research results or design standards without alterations. Therefore, it is necessary to develop an equation of the live load distribution factors fit for the design conditions of Korea, considering the standardized section of standard PSC I-girder bridges and the design strength of concrete. In this study, to develop an equation of the live load distribution factors, a parametric analysis and sensitivity analysis were carried out on the parameters such as width of bridge, span length, girder spacing, width of traffic lane, etc. As a result, the major variables to determine the size of distribution factors were girder spacing, overhang length and span length in case of external girders. For internal adjacent girders, the determinant factors were girder spacing, overhang length, span length and width of bridge. For internal girders, the factors were girder spacing, width of bridge and span length. Then, an equation of live load distribution factors was developed through the multiple linear regression analysis on the results of parametric analysis. When the actual practice engineers design a bridge with the equation of live load distribution factors developed here, they will determine the design of member forces ensuring the appropriate safety rate more easily. Moreover, in the preliminary design, this model is expected to save much time for the repetitive design to improve the structural efficiency of PSC I-girder bridges.

• Clinical and Experimental Pediatrics
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• v.49 no.7
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• pp.737-744
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• 2006

Purpose : To assess the usefulness of $^{99m}Tc-DISIDA$ scanning in the early evaluation of neonatal cholestasis and to verify the diagnostic value of this test in the differential diagnosis of biliary atresia. Methods : DISIDA scannings were performed and analyzed in 87 children(58 males and 29 females; age, 18-139 days, mean, 59.1 days) with neonatal cholestasis. Five groups according to the final diagnosis and the results of DISIDA scanning were analyzed by scatter plots using the parameters of age and the level of liver function tests(direct bilirubin, AST, ALT, ALP, GGT). The diagnostic sensitivity, specificity and accuracy of DISIDA scanning in the diagnosis of biliary atresia were compared between a higher bilirubin group and a lower bilirubin group(direct bilirubin level >5 mg/dL vs. <5 mg/dL) decided by the pattern of scatter plots. Results : DISIDA scannings in the diagnosis of biliary atresia were analyzed by high sensitivity(100 percent, 16/16) but lower specificity(70.4 percent, 50/71) and accuracy(75.9 percent, 66/87). False positivity(29.6 percent, 21/71) was higher in patients with a higher direct bilirubin level(42.5 percent for >5 mg/dL vs. 9.7 percent for <5 mg/dL, P<0.01). The age and the level of liver function tests(AST, ALT, ALP, GGT) analyzed by scatter plots revealed neither diagnostic value in predicting final diagnosis nor estimated the accuracy rate of DISIDA scanning in the evaluation of neonatal cholestasis. Conclusion : We suggest that DISIDA scannings should not be routinely used in evaluating neonatal cholestasis with elevated direct bilirubin level(>5 mg/dL), especially if it delays early diagnosis and surgical intervention.