• Clinical and Experimental Pediatrics
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• v.48 no.1
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• pp.34-39
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• 2005

Purpose : Perinatal complications associated with maternal smoking and alcohol ingestion in pregnancy have been well documented. But until now there has been no clinical data on it collected in our country. In this paper, we tried to research the association between maternal smoking and alcohol ingestion in pregnancy and the physical indices of the neonate at delivery among unmaried mothers from one charitable institution. Methods : We enlisted 125 unmarried with a history of smoking and alcohol consumption during pregnancy who delivered a baby in National Medical Center from March, 2001 to March, 2004 as a study group. As a control, 174 unmarried mothers without a history of smoking and alcohol were enlisted. Then, we compared the physical indices - birth weight, height, and the head circumference - of the neonates from both groups. Furthermore, we investigated the effects of the period and the quantity of maternal smoking and alcohol ingestion on the physical indices of the neonates from the both groups. Results : Low physical indices of neonates were found in the study group(either smoking group, or drinking group) compared with the control group. The quantity of smoking or drinking and the period of smoking or drinking have no significant effect on physical indices. Conclusion : We found that maternal smoking and alcohol result in the low physical index of neonates, and educational initiatives must be directed at expectant mothers to emphasize the harmful effects of smoking and alcohol ingestion in pregnancy.

• Journal of radiological science and technology
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• v.36 no.4
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• pp.291-297
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• 2013

This study is aimed to evaluate the effect of $T_{1/2}$ upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with $^{99m}TcO_4^-$ of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in $x^2$ test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of $T_{1/2}$ error from change of gradient with -0.25% to +0.25%, if $T_{1/2}$ is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see $T_{1/2}$ error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a tendency that count rate changes over time at this study, and we proved that it can effect $T_{1/2}$. And also, there is need of appropriate phantoms and the method of quality management like this study, because there are not any advice or limitation degrees for domestic medical purpose scintillation camera.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.119-124
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• 1997

Purpose: To assess the utility of magnetic resonance(MR) cerebral blood volume (CBV) map in the evaluation of brain tumors. Materials and Methods: We performed perfusion MR imaing preoperatively in the consecutive IS patients with intracranial masses(3 meningiomas, 2 glioblastoma multiformes, 3 low grade gliomas, 1 lymphoma, 1 germinoma, 1 neurocytoma, 1 metastasis, 2 abscesses, 1 radionecrosis). The average age of the patients was 42 years (22yr -68yr), composed of 10 males and S females. All MR images were obtained at l.ST imager(Signa, CE Medical Systems, Milwaukee, Wisconsin). The regional CBV map was obtained on the theoretical basis of susceptibility difference induced by first pass circulation of contrast media. (contrast media: IScc of gadopentate dimeglumine, about 2ml/sec by hand, starting at 10 second after first baseline scan). For each patient, a total of 480 images (6 slices, 80 images/slice in 160 sec) were obtained by using gradient echo(CE) single shot echo-planar image(EPI) sequence (TR 2000ms, TE SOms, flip angle $90^{\circ}$, FOV $240{\times}240mm,{\;}matrix{\;}128{\times}128$, slice-thick/gap S/2.S). After data collection, the raw data were transferred to CE workstation and rCBV maps were generated from the numerical integration of ${\Delta}R2^{*} on a voxel by voxel basis, with home made software (${\Delta}R2^{*}=-ln (S/SO)/TE). For easy visual interpretation, relative RCB color coding with reference to the normal white matter was applied and color rCBV maps were obtained. The findings of perfusion MR image were retrospectively correlated with Cd-enhanced images with focus on the degree and extent of perfusion and contrast enhancement. Results: Two cases of glioblastoma multiforme with rim enhancement on Cd-enhanced Tl weighted image showed increased perfusion in the peripheral rim and decreased perfusion in the central necrosis portion. The low grade gliomas appeared as a low perfusion area with poorly defined margin. In 2 cases of brain abscess, the degree of perfusion was similar to that of the normal white matter in the peripheral enhancing rim and was low in the central portion. All meningiomas showed diffuse homogeneous increased perfusion of moderate or high degree. One each of lymphoma and germinoma showed homogenously decreased perfusion with well defined margin. The central neurocytoma showed multifocal increased perfusion areas of moderate or high degree. A few nodules of the multiple metastasis showed increased perfusion of moderate degree. One radionecrosis revealed multiple foci of increased perfusion within the area of decreased perfusion. Conclusion: The rCBV map appears to correlate well with the perfusion state of brain tumor, and may be helpful in discrimination between low grade and high grade gliomas. The further study is needed to clarify the role of perfusion MR image in the evaluation of brain tumor.

• Childhood Kidney Diseases
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• v.6 no.1
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• pp.61-67
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• 2002

Purpose: The urinary mass screening program in school aged population has been performed since 1981, but the consensus on the follow-up schedule and the management of isolated proteinuria has not been reached yet. The aim of this study was to investigate the cause of isolated proteinuria and to propose a guideline for the treatment and follow-up afterwards Methods: The medical records of 114 cases of isolated proteinuria detected through the analysis of urinary mass screening and evaluated at the pediatric outpatient clinic of Asan Medical Center from January 1990 to July 2001 have been reviewed. Results: The classification of isolated proteinuria was as follows. Transient proteinuria $32\%$, orthostatic proteinuria $65\%$, persistent proteinuria $3\%$, In orthostatic proteinuria group, daytime and nighttime proteinuria were $319.2{\pm}189.1\;mg/dL$ and $56.5{\pm}56.1\;mg/dL$. In persistent proteinuria group, daytime and nighttime proteinuria were $1140{\pm}540.5\;mg/dL$ and $289{\pm}58\;mg/dL$. After 30 month follow-up, 2 cases of persistent proteinuria were needed renal biopsy and 1 case revealed focal segmental glomerular sclerosis. In all cases, serum creatinine, albumin and complements levels were normal. In the orthostatic proteinuria group, no significant renal diseases were detected. Conclusion: Since most of the isolated proteinuria detected through the school urinary mass screening were orthostatic proteinuria or transient proteinuria, initially aggressive diagnostic method such as renal biopsy is not needed and regular follow- up with quantitation of proteinuria is warranted.(J Korean Soc Pediatr Nephrol 2002 ; 6 61-7)

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.100-108
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• 2001

Purpose : We investigated the incidence and predisposing factors of pulmonary embolism in minimal change nephrotic syndrome(MCNS). Methods : Lung perfusion scan using 99mTC-MAA were done on 14 patients who were diagnosed to minimal change nephrotic syndrome. Group h: Five patients who had perfusion defects on scan, Group B; Nine patients who had no perfusion defect on scan. Between the two groups, the differences of platelet number, hematocrits, albumin, cholesterol, triglyceride, proteinuria were evaluated. Results : Five patients were found to have perfusion defect consistent with pulmonary embolism($35.7\%$). However, there were minimal or no respiratory symptoms and signs. In our laboratory studies, the mean proteinuria on admissions was $676{\pm}31\;mg/m2/hr$ in the group with pulmonary embolism, and $313{\pm}28\;mg/m2/hr$ in the group without pulmonary embolism. There were more severe proteinuria in group with pulmonary embolism(P<0.05). The mean platelet count at early stage of remission after steroid treatment was $746,600{\pm}280,000/mm3$ in the group with pulmonary embolism, $511,890{\pm}90,000/mm3$ in the group without pulmonary embolism. There were significant difference of platelet count between the two groups(P<0.01). In patients with pulmonary embolism, there were more higher and sustained increasement of platelet count. All cases of pulmonary embolism were treated with dipyridamole(5 mg/kg). In 4 cases the perfusion defects were improved in two weeks, however, one case showed persistent perfusion defect after 1 month. Conclusion : Our study suggested that pulmonry embolism might be one of tile major complications in childhood MCNS The occurrence rate was correlated with severity of proteinuria before treatment and sustained increasement of platelet counts in early remission state after steroid treatment. Therefore, the scintigraphic pulmonary perfusion study is mandatory in childhood MCNS, especially in the high risk patients, such as the patients with severe proteinuria and sustained increasement of platelet count. (J Korean Soc Pediatr Nephrol 2001;5 : 100-8)

• Childhood Kidney Diseases
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• v.13 no.2
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• pp.146-152
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• 2009

Purpose : We performed this study to evaluate the incidence and clinical significance of antiphospholipid antibodies (aPL Ab) in Korean children with Henoch-$Sch{\ddot{o}}nlein$ purpura (HSP). Methods : The medical records of 62 patients (31 boys and 31 girls) aged $46.0{\pm}3.1$ (1-16) years with a clinical diagnosis of HSP based on the EULAR/PReS criteria were reviewed retrospectively. From the years 2007 to 2009, the sera from children with acute HSP were tested for aPL Ab such as LA, anti-cardiolipin antibody and anti-${\beta}_2$ glycoprotein I antibody. Results : LA was positive in 18 (29%) of the 62 patients with HSP and We divided the patients into the two groups LA positive group (N=18) and LA negative group (N=44). There were no significant differences between the two groups with regard to abdominal pain, arthralgia and renal involvement, but LA positive group had significantly higher C-reactive protein ($4.3{\pm}7.2$ mg/dL vs. $1.3{\pm}1.8$ mg/dL, P=0.035), erythrocyte sedimentation rate ($37.5{\pm}26.2$ mm/hr vs. $25.1{\pm}22.6$ mm/hr, P= 0.039), IgM ($148.1{\pm}48.4$ mg/dL vs. $114.9{\pm}41.5$ mg/dL, P=0.024), C3 ($143.1{\pm}21.9$ mg/dL vs. $129.7{\pm}24.5$ mg/dL, P=0.048) and C4 levels ($30.9{\pm}6.3$ mg/dL vs. $24.9{\pm}7.8$ mg/dL, P=0.002) compared with LA negative group. Conclusion : We found that the incidence of positive aPL Ab tests was relatively higher in Korean children with HSP and the presence of aPL Ab was associated with acute inflammatory process of HSP. These results suggest that the aPL Ab are involved in the pathogenesis of HSP in children.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.13-22
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• 2005

It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.3
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• pp.273-283
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• 2020

Because of climate change, the occurrence of localized and heavy rainfall is increasing. It is important to predict floods in urban areas that have suffered inundation in the past. For flood prediction, not only numerical analysis models but also machine learning-based models can be applied. The LSTM (Long Short-Term Memory) neural network used in this study is appropriate for sequence data, but it demands a lot of data. However, rainfall that causes flooding does not appear every year in a single urban basin, meaning it is difficult to collect enough data for deep learning. Therefore, in addition to the rainfall observed in the study area, the observed rainfall in another urban basin was applied in the predictive model. The LSTM neural network was used for predicting the total overflow, and the result of the SWMM (Storm Water Management Model) was applied as target data. The prediction of the inundation map was performed by using logistic regression; the independent variable was the total overflow and the dependent variable was the presence or absence of flooding in each grid. The dependent variable of logistic regression was collected through the simulation results of a two-dimensional flood model. The input data of the two-dimensional flood model were the overflow at each manhole calculated by the SWMM. According to the LSTM neural network parameters, the prediction results of total overflow were compared. Four predictive models were used in this study depending on the parameter of the LSTM. The average RMSE (Root Mean Square Error) for verification and testing was 1.4279 ㎥/s, 1.0079 ㎥/s for the four LSTM models. The minimum RMSE of the verification and testing was calculated as 1.1655 ㎥/s and 0.8797 ㎥/s. It was confirmed that the total overflow can be predicted similarly to the SWMM simulation results. The prediction of inundation extent was performed by linking the logistic regression with the results of the LSTM neural network, and the maximum area fitness was 97.33 % when more than 0.5 m depth was considered. The methodology presented in this study would be helpful in improving urban flood response based on deep learning methodology.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.4
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• pp.229-241
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• 2006

Global air temperature has risen by $0.6^{\circ}C$ over the last one hundred years due to increased atmospheric greenhouse gases. Moreover, this global warming trend is projected to continue in the future. This study was carried out to evaluate spatial variations in rice production areas by simulating rice-growth and development with projected high resolution climate data in Korea far 2011-2100, which was geospatially interpolated from the 25 km gridded data based on the IPCC SRES A2 emission scenario. Satellite remote sensing data were used to pinpoint the rice-growing areas, and corresponding climate data were aggregated to represent the official 'crop reporting county'. For the simulation experiment, we used a CERES-Rice model modified by introducing two equations to calculate the leaf appearance rate based on the effective temperature and existing leaf number and the final number of leaves based on day-length in the photoperiod sensitive phase of rice. We tested the performance of this model using data-sets obtained from transplanting dates and nitrogen fertilization rates experiments over three years (2002 to 2004). The simulation results showed a good performance of this model in heading date prediction [$R^2$=0.9586 for early (Odaebyeo), $R^2$=0.9681 for medium (Hwasungbyeo), and $R^2$=0.9477 for late (Dongjinbyeo) maturity cultivars]. A modified version of CERES-Rice was used to simulate the growth and development of three Japonica varieties, representing early, medium, and late maturity classes, to project crop status for climatological normal years between 2011 and 2100. In order to compare the temporal changes, three sets of data representing 3 climatological years (2011-2040, 2041-2070, and 2071-2100) were successively used to run the model. Simulated growth and yield data of the three Japonica cultivars under the observed climate for 1971-2000 was set as a reference. Compared with the current normal, heading date was accelerated by 7 days for 2011-2040 and 20 days for 2071-2100. Physiological maturity was accelerated by 15 days for 2011-2040 and 30 days for 2071-2100. Rice yield was in general reduced by 6-25%, 3-26%, and 3-25% per 10a in early, medium, and late maturity classes, respectively. However, mid to late maturing varieties showed an increased yield in northern Gyeonggi Province and in most of Kwangwon Province in 2071-2100.

• Journal of Biomedical Engineering Research
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• v.25 no.4
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• pp.261-268
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• 2004

Osteoporosis is a clinical condition in which the amount of bone tissue is reduced and the likelihood of fracture is increased. It is known that the electrical property of the bone is related to its density, and, in particular, the electrical resistance of the bone decreases as the bone loss increases. This implies that the electrical property of bone may be an useful parameter to diagnose osteoporosis, provided that it can be readily measured. The study attempted to evaluate the electrical conductivity of bone using a technique of electrical impedance tomography (EIT). It nay not be easy in general to get an EIT for the bone due to the big difference (an order of 2) of electrical properties between the bone and the surrounding soft tissue. In the present study, we took an adaptive mesh regeneration technique originally developed for the detection of two phase boundaries and modified it to be able to reconstruct the electrical conductivity inside the boundary provided that the geometry of the boundary was given. Numerical simulation was carried out for a tibia phantom, circular cylindrical phantom (radius of 40 mm) inside of which there is an ellipsoidal homeogenous tibia bone (short and long radius are 17 mm and 15 mm, respectively) surrounded by the soft tissue. The bone was located in the 15 mm above from the center of the circular cross section of the phantom. The electrical conductivity of the soft tissue was set to be 4 mS/cm and varies from 0.01 to 1 ms/cm for the bone. The simulation considered measurement errors in order to look into its effects. The simulated results showed that, if the measurement error was maintained less than 5 %, the reconstructed electrical conductivity of the bone was within 10 % errors. The accuracy increased with the electrical conductivity of the bone, as expected. This indicates that the present technique provides more accurate information for osteoporotic bones. It should be noted that tile simulation is based on a simple two phase image for the bone and the surrounding soft tissue when its anatomical information is provided. Nevertheless, the study indicates the possibility that the EIT technique may be used as a new means to detect the bone loss leading to osteoporotic fractures.