• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.47-52
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• 2018

Brain perfusion CT scanning is often employed usefully in clinical conditions as it accurately and promptly provides information about the perfusion state of patients having acute ischemic stroke with a lot of time constraints and allows them to receive proper treatment. Despite those strengths of it, it also has a serious weakness that Lens may be exposed to a lot of dose of radiation in it. In this study, as a way to reduce the dose of radiation to Lens in brain perfusion CT scanning, this researcher conducted an experiment with Bismuth shielding and change of patients' position. TLD (TLD-100) was placed on both lens using the phantom (PBU-50), and then, in total 4 positions, parallel to IOML, parallel to IOML (Bismuth shielding), parallel to SOML, and parallel to SOML (Bismuth shielding), brain perfusion scanning was done 5 times for each position, and dose to Lens were measured. Also, to examine how the picture quality changed in different positions, 4 areas of interest were designated in 4 spots, and then, CT number and noise changes were measured and compared. According to the results of conducting one-way ANOVA on the doses measured, as the significance probability was found to be 0.000, so there was difference found in the doses of radiation to crystalline lenses. According to the results of Duncan's post-hoc test, with the scanning of being parallel to IOML as the reference, the reduction of 89.16% and 89.66% was observed in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding) respectively, so the doses to Lens reduced significantly. Next, in the scanning of being parallel to IOML (Bismuth shielding), the reduction of 37.12% was found. According to the results, reduction in the doses of radiation was found the most significantly both in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding). With the limit of the equivalent dose to Lens as the reference, this researcher conducted comparison with the dose to occupational exposure and dose to Public exposure in the scanning of being parallel to IOML and found 39.47% and 394.73% respectively; however in the scanning of being parallel to SOML (Bismuth shielding), considerable reduction was found as 4.08% and 40.8% respectively. According to the results of evaluation on picture quality, every image was found to meet the evaluative standards of phantom scanning in terms of the measurement of CT numbers and noise. In conclusion, it would be the most useful way to reduce the dose of radiation to Lens to use shields in brain perfusion CT scanning and adjust patients' position so that their lens will not be in the field of radiation.

• Korean Journal of Cognitive Science
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• v.20 no.2
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• pp.125-154
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• 2009

This paper describes the possibility of human physiological data, especially brain-wave activity, to detect cognitive overload, a phenomenon that may occur while learner uses an e-learning system. If it is found that cognitive overload to be detectable, providing appropriate feedback to learners may be possible. To illustrate the possibility, while engaging in cognitive activities, cognitive load levels were measured by EEG (electroencephalogram) to seek detection of cognitive overload. The task given to learner was a computerized listening and recall test designed to measure working memory capacity, and the test had four progressively increasing degrees of difficulty. Eight male, right-handed, university students were asked to answer 4 sets of tests and each test took from 61 seconds to 198 seconds. A correction ratio was then calculated and EEG results analyzed. The correction ratio of listening and recall tests were 84.5%, 90.6%, 62.5% and 56.3% respectively, and the degree of difficulty had statistical significance. The data highlighted learner cognitive overload on test level of 3 and 4, the higher level tests. Second, the SEF-95% value was greater on test3 and 4 than on tests 1 and 2 indicating that tests 3 and 4 imposed greater cognitive load on participants. Third, the relative power of EEG gamma wave rapidly increased on the 3rd and $4^{th}$ test, and signals from channel F3, F4, C4, F7, and F8 showed statistically significance. These five channels are surrounding the brain's Broca area, and from a brain mapping analysis it was found that F8, right-half of the brain area, was activated relative to the degree of difficulty. Lastly, cross relation analysis showed greater increasing in synchronization at test3 and $4^{th}$ at test1 and 2. From these findings, it is possible to measure brain cognitive load level and cognitive over load via brain activity, which may provide atimely feedback scheme for e-learning systems.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1458-1469
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• 2015

This study was carried out to investigate the nitrite scavenging activities (NSA) of nine kinds of wild vegetables in a $NaNO_2$ model system and nitrite of Chinese cabbage as well as the inhibitory effect of kimchi containing a mixture of wild vegetables (MWV) with nitrite scavenging activity on brain neuronal cell death. NSA was higher at pH 1.2 than pH 4.2 in all samples. NSA of extracts from sprouts of Oenothera laciniata and Aster scaber (AS) was above 90% at pH 1.2. AS, Codonopsis lanceolate (CL), Adenophora triphylla (AT), Platycodon grandiflorum (PG), and Taraxacum officinale (TO) extracts showed significantly higher levels of NSA than those from other extracts at pH 4.2. CL, AT, PG, and TO extracts showed high NSA on nitrite of Chinese cabbage. In addition, the effects of MWV on antioxidant and brain neuronal cell death induced by oxidative stress were investigated in human brain neuroblastoma SK-N-SH cells. MWV extract attenuated $H_2O_2$-induced cell death and reactive oxygen species (ROS) generation in SK-N-SH cells. MWV extract showed significantly higher DPPH radical scavenger activity when compared to normal kimchi extract. MWV extract showed an inhibitory effect on brain neuronal cell death against oxidative stress by antioxidant activities.

• Pediatric Infection and Vaccine
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• v.12 no.1
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• pp.67-74
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• 2005

Purpose : The incidence of mortality associated with respiratory difficulties is decreasing nowadays contributed to the development of neonatology. However, complications associated with mechanical ventilator are increasing. This study is to determine clinical manifestations, diagnositc availability of the endotracheal tip culture in patients with Ventilator-Associated Pneumonia(VAP) in neonatal intensive care unit(NICU). Methods : A retrospective analysis of 50 neonates who were admitted to the NICU of Kangnam Sacred Heart Hospital and had given mechanical ventilator from 1 January 2000 to 30 June 2003. VAP group defined as neonates who had pneumonia with mechanical ventilation longer than 48 hours. They were classified into VAP group(n=13) and control group (n=37) and the prevalence, microorganisms cultured from the endotracheal tube tip and risk factors were investigated. Results : The prevalence of VAP was 26.0%(n=13) and the most dominant microorganism cultured in our NICU was methicillin-resistant coagulase negative staphylococcus(MR-CNS) in 4 cases. Other microorganisms were Pseudomonas, Enterobacter, methicillin-resistant Staphylococcus aureus(MRSA) and Klebsiella. Gestational age, birth weight, Apgar score, respiratory distress syndrome, retinopathy of prematurity, bronchopulmonary dysplasia, sepsis, renal failure, pulmonary hemorrhage, pneumothorax were not different significantly between two groups except intraventricular hemorrhage(P<0.001) and patent ductus arteriosus(P<0.05). Duration of hospital stay and mortality rate were also not different significantly. Conclusion : VAP occurred at a significant rate among mechanically ventilated NICU patients. Despite of limitation of encotracheal tip culture, the most common microorganism was MR-CNS. We should be aware of occurrence of VAP in NICU neonate who were with mechanical ventilator and should treat with great care.

• Pediatric Infection and Vaccine
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• v.24 no.3
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• pp.160-167
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• 2017

Purpose: Because children with asplenia have an increased risk of fulminant infection associated with a high fatality, chemoprophylaxis, and vaccinations against encapsulated bacteria are recommended. However, there have been few reports of the burden of severe bacterial infection and the current status of chemoprophylaxis and immunization among children with asplenia in Korea. Methods: We conducted a retrospective study including children with asplenia who were treated at our institute between January 1997 and December 2016. Results: From a total of 213 children with asplenia, 114 (53.5%) had congenital asplenia and 58 (27.2%) had functional asplenia. The remaining 41 (19.3%) had acquired asplenia with the median age at splenectomy being 12.2 years (range, 5.0 to 16.9 years); the most common cause of splenectomy was hereditary spherocytosis (39.0%). The chemoprophylaxis rate was 16.4%. The immunization rates were 44.1% for pneumococcus, 53.0% for Haemophilus influenzae type B, and 10.7% for meningococcus. The incidence of invasive bacterial infection among children with asplenia was 0.28/100 person-year; a total of six episodes (2.8%) were observed in five patients with congenital asplenia and one patient with functional asplenia. The median age for these infections was 15 months (range, 4 to 68 months). Five of the six episodes were bacteremia, and the other was meningitis. The most common pathogen was Streptococcus pneumoniae (n=3), followed by H. influenzae (n=1). Three of the six patients (50.0%) died, all of whom had pneumococcal bacteremia. None of the six had chemoprophylaxis or proper vaccinations. Conclusions: Although there is an increased risk of a severe infection proper vaccinations and chemoprophylaxis are still lacking. Physicians should be encouraged to implement appropriate chemoprophylaxis and immunizations for patients with asplenia.

• Tuberculosis and Respiratory Diseases
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• v.60 no.1
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• pp.57-64
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• 2006

Background : Recently, there have been several studies showing that irinotecan hydrochloride, a topoisomerase I inhibitor, is effective against extensive disease(ED) small cell lung cancer (SCLC). We conducted a phase II trial to evaluate the efficacy and toxicity of irinotecan plus cisplatin as a 1st line therapy for both limited and extensive disease SCLC. Methods : The study was conducted between January 2002 and June 2004. Patients were treated with $60mg/m^2$ irinotecan on day 1, 8, 15 and $60mg/m^2$ cisplatin on day 1, every 4 weeks. During concurrent thoracic irradiation for limited disease (LD)-SCLC patients, dose of irinotecan was reduced to $40mg/m^2$. Prophylactic cranial irradiation was given to patients with complete remission (CR) after chemotherapy. Results : Median ages of LD- and ED- SCLC were 64 years and performance status (PS) was 0-2. In patients with LD-SCLC, the response rate after concurrent chemoradiotherapy was 85% (CR, 6; Partial response [PR], 11). The median survival was 20 months (95% CIs, 15.6 to 24.4) with 1-and 2-year survival rates of 85% and 35%, respectively. Median progression free survival (PFS) was 12 months (95% CIs, 6.2 to 18.1) with 1- year PFS of 36%. In ED-SCLC, the response rate was 83.4% (CR, 1; PR, 14). The median survival was 14.5 months (95% CIs, 8.8 to 20.1) with 1-year survival rates of 75%. Median PFS was 6.3 months (95% CIs, 5.6 to 7.1) with 1- year PFS of 20%. The major toxicities (grade 3 or 4) of this regimen included leukopenia, anemia, thrombocytopenia, nausea/vomiting, and diarrhea without life threatening complication. Conclusion : Our data shows that the combination of irinotecan plus cisplatin as a first line therapy is effective and tolerable in the treatment of both LD- and ED- SCLC.

• Clinical and Experimental Pediatrics
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• v.49 no.2
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• pp.187-191
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• 2006

Purpose : Malformation of cortical development(MCD) constitutes an important etiology of intractable epilepsy and is considered an indication for surgical treatments, though their efficacy is limited and variable depending on MCD's location or distribution. Ketogenic diets are widely known to be effective, but as little study has been made concerning their efficacy on epilepsy with MCD, we evaluated the efficacy of ketogenic diets on MCD patients compared with that of epileptic surgery, which is more invasive. Methods : We performed retrospective studies and analyse on 30 patients with MCD diagnosed by brain MRI and treated with ketogenic diets for intractable epilepsy since 1998, checking decreases in their seizure episodes after starting the diets. Results : Cortical dysplasia was observed in 24(80.0 percent) patients as the most common type of MCD. Also, MCD was observed in unilateral hemisphere most commonly, in 23(76.7 percent) patients; it was observed in both hemispheres in 7(23.3 percent) patients. Nine(30.0 percent) out of 30 patients became seizure-free after starting ketogenic diets, and 14(46.7 percent) patients experienced 50 percent seizure reductions as well. Age of starting the diet or the duration of epilepsy period before starting showed no statistical relationship with the efficacy of the diet. Though the younger the patient and the longer the treatment the more effective the diet seemed to be, there was no statistical correlation between them. The location of MCD showed no significance neither. Conclusion : Considering various limits and invasiveness of surgical treatment, a ketogenic diet could be a good tool in treating children with intractable epilepsy with MCD.

• Tuberculosis and Respiratory Diseases
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• v.47 no.6
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• pp.768-774
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• 1999

Background: It is well known that rifampin decreases the hypoprothrombinemic effect of warfarin by induction of cytochrome P-450 enzyme in healthy volunteer. However, in patients the dosage schedule of warfarin during rifampin therapy is not established. Therefore, patients taking both rifampin and warfarin were reviewed to find out the adequate dosage schedule of warfarin in addition to side effects by interaction of two drugs. Method: Patients taking both rifampin and warfarin were retrieved from patients who were admitted due to heart disease and tuberculosis at Boochun Sejong Hospital from January of 1995 to August of 1999. To decide the adequate dosage of warfarin, the dosage of warfarin before, during, and after rifampin was evaluated in patients who kept adequate hypoprothrombinemic effect of warfarin during rifampin. To decide the adequate dosage schedule of warfarin, the time interval from the beginning of rifampin to normalization of prothrombin time(INR$\geq$1.1) was evaluated. And, the side effects by interaction of two drugs were reviewed. Results: All 12 patients taking both rifampin and warfarin were retrieved. Among them only 6 kept adequate hypoprothrombinemic effect of warfarin during rifampin. The dosage of warfarin during rifampin was $2.4{\pm}0.6$(mean$\pm$standard deviation) times as much as that before rifampin but the dosage after rifampin was the same as that before rifampin. The time interval from the beginning of rifampin to normalization of prothrombin time was $5.8{\pm}2.9$(mean${\pm}$standard deviation) days. 2 out of 12 had complication related to the interaction of rifampin and warfarin, one cerebral embolism just after the beginning of rifampin and the other cerebral hemorrhage just after the discontinuation of rifampin. Conclusion: When both rifampin and warfarin are prescribed, it would be a possible method to be confirmed by prospective study that warfarin be gradually increased about 2 times more than that without rifampin over 1 week or so after the beginning of rifampin and be tapered to the same dosage as that before rifampin when rifampin is discontinued. And, it would be prudent that prothrombin time be monitored frequently during rifampin and warfarin therapy, especially the beginning or discontinuation of rifampin.

• Korea journal of population studies
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• v.28 no.2
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• pp.1-32
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• 2005

The optimum population of a society or country can be defined as 'the population growth path that maximizes the welfare level of the society over the whole generations of both the present and the future, under the paths allowed by its endowments of production factors such as technology, capital and labor'. Thus, the optimum size or growth rate of population depends on: (i) the social welfare function, (ii) the production function, and (iii)demographic economic interrelationship which defines how the national income is disposed into consumption(birth and education of children included) and savings on the one hand and how the demographic and economic change induced thereby, in turn, affect production capacities on the other. The optimum population growth path can, then, be derived in the process of dynamic optimization of (i) under the constraints of (ii) and (iii), which will give us the optimum population growth rate defined as a function of parameters thereof. This paper estimates the optimum population growth rate of Korea by: specifying (i), (ii), and (iii) based on the recent development of economic theories, solving the dynamic optimization problem and inserting empirical estimates in Korea as the parametric values. The result shows that the optimum path of population growth in Korea is around TFR=1.81, which is affected most sensitively, in terms of the size of the partial elasticity around the optimum path, by the cost of children, share of capital income, consumption rate, time preference, population elasticity of utility function, etc. According to a survey implemented as a follow up study, there are quite a significant variations in the perceived cost of children, time preference rate, population elasticity of utility across different socio-economic classes in Korea, which implied that, compared to their counterparts, older generation and more highly educated classes prefer higher growth path for the population of Korea.

• Korea journal of population studies
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• v.28 no.2
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• pp.97-129
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• 2005

Korean society recently witnesses a rapid lllcrease of suicide across all ages. In particular, suicide in old ages jumps up ill a very unexpected way. Furthermore, the order of suicide in the cause of death across all ages is becoming higher and higher in Korea. This study provides details of suicide that occurs in Korean society with the comparison to that of Japan at the descriptive level. It is not well known why suicide in Korean surges recently. Several previous research show the possibility that surging suicide is closely related to the worsened economic conditions especially since the economic crisis in 1997. They adopt economic growth, unemployment rate, income distribution, household finance index as economic indicators in their research. This study also adopts those indicators and conducts a correlation analysis in two periods, 1990-1997 and 1998-2004. It is found that there is no correlation between economic indicators and suicide in the period of 1990-1997. On the other hand, there is a very strong correlation between income distribution and suicide in the period of 1998-2004. Other economic indicators except income distribution does not have any significant correlation with suicide. This finding suggests that currently increasing suicide in Korea may be a result of economic polarization, which has been worsened since the economic crisis in 1997.