• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.3
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• pp.71-79
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• 2023

It is not efficient to install a maintenance system that measures seismic acceleration and displacement on all bridges and buildings to evaluate the safety of structures after an earthquake occurs. In order to maintain this, an on-site investigation is conducted. Therefore, it takes a lot of time when the scope of the investigation is wide. As a result, secondary damage may occur, so it is necessary to predict the safety of individual structures quickly. The method of estimating earthquake damage of a structure includes a finite element analysis method using approved seismic information and a structural analysis model. Therefore, it is necessary to predict the seismic information generated at arbitrary location in order to quickly determine structure damage. In this study, methods to predict the ground response spectrum and acceleration time history at arbitrary location using linear estimation methods, and artificial neural network learning methods based on seismic observation data were proposed and their applicability was evaluated. In the case of the linear estimation method, the error was small when the locations of nearby observatories were gathered, but the error increased significantly when it was spread. In the case of the artificial neural network learning method, it could be estimated with a lower level of error under the same conditions.

• Journal of Life Science
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• v.33 no.7
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• pp.538-548
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• 2023

The research has been conducted on the isolation of antimicrobial compounds from plant natural extracts and their potential application in oral health care products. This study aimed to investigate the antimicrobial mechanism by analyzing the changes in gene expression of Streptococcus mutans, a major oral pathogen, in response to complex compounds extracted from Aralia continentalis and Arctii Semen using organic solvents. Transcriptome analysis (RNA-seq) revealed that both natural extracts commonly upregulated or downregulated the expression of various genes associated with different metabolic and physiological activities. Three genes (SMU_1584c, SMU_2133c, SMU_921), particularly SMU_921 (rcrR), known as a transcription activator of two sugar phosphotransferase systems (PTS) involved in sugar transport and biofilm formation, exhibited consistent high expression levels. Additionally, component analysis of the A. continentalis extract was performed to compare its effects on gene expression changes with the A. Semen extract, and two active compounds were identified through gas chromatography-mass spectrometry (GC-MS) analysis of the active fraction. The n-hexane fraction (ACEH) from the A. continentalis extract exhibited antibacterial specificity against S. mutans, leading to a significant reduction in the viable cell counts of Streptococcus sanguinis and Streptococcus gordonii among the tested multi-species bacterial communities. These findings suggest the broad-spectrum antibacterial activity of the A. continentalis extract and provide essential foundational data for the development of customized antimicrobial materials by elucidating the antibacterial mechanism of the identified active compounds.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2D
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• pp.163-170
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• 2008

According to the rules, a crash cushion is supposed to set up products that is satisfied with the standard of a performance test after performing the car crash test by road safety facilities and management guide. For development of crash cushion, performance should be estimated through the car crash test eventually. However, there is no reasonable design method which considers passenger's safety and only depend on crash test without an alternative plan. Therefore it incurs a loss materially and takes a lot. Therefore, we are asked to create a systematic design of the crash cushion. This study shows that a scientific basis of applying single degree of freedom when it designs the crash cushion after analyzing vehicle crash test data of crash cushion and also represents design of crash cushion through single degree of freedom response spectrum using calculated by crash test data on crash cushion.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.15 no.2
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• pp.143-151
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• 2004

Objectives : Child and adolescent onset obsessive compulsive disorder(C-OCD) is known to be associated with poor drug response, high comorbid rate and strong genetic tendencies. Till now studies for C-OCD have been very rare in Korea. We conducted this study to investigate the informations about clinical features, familial psychiatric loading, treatment profiles and course of server C-OCD from the retrospective analysis of inpatient data of Seoul National University Children's Hospital. Method : Retrospective chart review and data analysis was performed. Twenty(male 16 : female 4) patients with final C-OCD diagnosis by DSM-IV at discharge from 1994 to 2002 were found and their medical chart, psychological data, family interview data and nursing reports were collected and analyzed. Results : 1) The sex ratio of C-OCD was male dominant(4:1). 2) Phenomenological, most common obsession was pathologic doubt, contamination fear, followed by aggressive obsession, need for symmetry, sexual obsession, most common compulsion was checking and washing, followed by breathing, movement, symmetry, repetitive asking, hoarding, mental compulsion. 3) Most common comorbid diagnosis was depression. Other axis-I diagnosis associated OCD were anxiety disorder, tic disorder, conduct and oppositional defiant disorder and psychosis. 4) Regarding psychiatric familial loadings, 17 patients(85%) had relatives with psychiatric disorders, OC-spectrum disorders(OCD or OCPD) were found in 9 patients(45%). 5) The majority of patients(75%) have received SSRI and antipsychotics treatment. The response rate above 'moderate improved" by CGI was 75%. 6) During follow-up period in outpatient clinic, five patients(25%) showed continuous complete remission, 10 patients (50%) did residual symptoms with chronic course. Conclusion : This seems to be the first systemic investigation of severe pediatric OCD patients in Korea. The children & adolescents with severe OCD in inpatient-setting showed the high comorbid rate, familial psychiatric loading, and combined pharmacotherapy with antipsychotics, As for symptoms, high rate of aggressive-sexual obsession and atypical compulsions like breathing and moving was reported in this study. Severe pediatric OCD patients, however, responded well to the combined SSRI and antipsychotics regimen.

• Clinical and Experimental Pediatrics
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• v.46 no.2
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• pp.143-153
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• 2003

Purpose : Infection with Shiga-like toxin (SLT)-producing Escherichia coli, an emerging human pathogen found particularly in young children under 5 years of age, causes a spectrum of illnesses with high morbidity and mortality, ranging from diarrhea to hemorrhagic colitis and hemolytic uremic syndrome. Host mediators play an important role in the pathogenesis of SLT-I toxicity. The experiments described here were designed to investigate the effect of SLT-I on TNF-${\alpha}$ production and to understand the effect of TNF-${\alpha}$ on GB3 expression. We also further examine the relationship between the Gb3 level and the differential susceptibility of cells to the cytotoxic action of SLT-I. Methods : The effect of purified SLT-1 from E. coli O157 : H7 (ATCC 43890) on tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) production in Raw264.7 cells was investigated. Many mediators regulate endothelial cell membrane expression of the glycolipid globotriaosyleramide (Gb3), which serves as the toxin receptor, suggesting that the host response to the toxin or other bacterial products may contribute to pathogenesis by regulating target cell sensitivity to the toxins. Therefore, the relationships between Gb3 expression and cytotoxicity against SLT-I on three types of cells were evaluated. Results : Detectable levels of TNF-${\alpha}$ were produced as early as six hours after induction and continued to increase during 48 hours by SLT-I. It was also found that Vero cells and dendritic cells (DC2.4 cells) expressed high levels of Gb3, 83% and 68%, respectively, and that Raw264.7 cells had a low level of Gb3 (29%) and appeared refractory to cytotoxicity against SLT-I. Vero cells and DC2.4 cells expressing high levels of Gb3 were highly susceptible to SLT-I. Furthermore, macrophages showed a resistance to SLT-I cytotoxicity, despite the fact that Gb3 expression was enhanced. Conclusion : These results strongly suggest that the expression of Gb3 is necessary but not sufficient to confer sensitivity of macrophages to SLT-I and further underpin the important role of SLT-I and its Gb3 receptors in the pathogenesis of E. coli O157 infection.

• Journal of Life Science
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• v.26 no.11
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• pp.1245-1252
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• 2016

As a research of inflammation inhibitory activity using natural resource, the inflammation inhibitory activity by purified active compound from Rhododendron mucronulatum flower was experimented. Rhododendron mucronulatum flower components were purified and separated with Sephadex LH-20 and MCI gel CHP-20 column chromatography, Purified compound was confirmed as myricetin by $^1H-NMR$, $^{13}C-NMR$ and Fast atom bombardment (FAB)-Mass spectrum to have inhibition activity on inflammatory factors secreted by Raw 264.7 cells in response to lipopolysaccharide stimulation. Myricetin inhibited nitric oxide (NO) expression in a concentration dependent manner, approximately 40% inhibition was observed at a concentration of $50{\mu}M$. The inhibition effect of myricetin on inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expression was 20% and 80%, respectively, at a concentration of $25{\mu}M$. Myricetin also inhibited expression of the inflammatory cytokines, tumor necrosis factor $(TNF)-{\alpha}$, interleukin $(IL)-1{\beta}$, IL-6 and prostaglandin $E_2(PGE_2)$ in a concentration dependent manner; a concentration of $50{\mu}M$, 70%, 80%, 80% and 95% inhibition was observed, respectively. Therefore myricetin isolated from Rhododendron mucronulatum flowers is expected to have an anti-inflammatory effect in Raw 264.7 cell induced by lipopolysaccharides. The results can be expected myricetin from Rhododendron mucronulatum flower to use as functional resource for anti-inflammatory activity.

• Science of Emotion and Sensibility
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• v.10 no.3
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• pp.411-418
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• 2007

Exposure to low frequency noise(LFN) can lead to vibroacoustic diseases(VADs), which include a systemic disease with lesions in a broad spectrum of organs and a psychiatric condition. It is known that VAD is an established risk factor for the development of many psychological conditions in humans and rodents, including major depression and anxiety disorder. The present study investigated the effects of LFN on neuronal stress responses in the rat brain. The neuronal expression of the proto-oncogene c-fos in the paraventricular nucleus(PVN) of the hypothalamus and tyrosine hydroxylase(TH) in the LC was observed. The immunocytochemical detection of the Fos protein and TH has been used as a marker of neuronal activation in response to stress. In addition, corticosterone concentration was evaluated by using an enzyme-linked immunosorbent assay(ELISA). The LFN groups were exposed to 32.5Hz and 125Hz of noise(4hr/day for 2days). The numbers of c-fos and TH-immunoreactive cells in the PVN and LC were significantly increased in the LFN groups(32.5Hz and 125Hz) compared to the normal group. Corticosterone concentration in plasma was also increased in LFN groups. The present results demonstrated that exposure with LFN produced a pronounced increase in expression of c-Fos and TH in stress-relevant brain areas. These results suggest that the neural characteristics involved in LFN are similar to those activated by typical processive stressors. These results also suggest that the central and peripheral activations by LFN may be related to LFN-related negative behavioral dysfunctions such as VADs.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.75-84
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• 1994

The need for assessment of ureteric function in the patient with an obviousely dilated ureter has increased particularly with the added spectrum of asymptomatic patients presenting with hydrone-phrosis and hydroureter on antenatal and perinatal ultrasound. To assess the influence of ureteral status on kidney washout during $^{99m}Tc$-DTPA diuretic renography, ureteral images were reviewed in 80 children referred for hydronephrosis. A scintigraphically abnormal ureter was defined as an intense and continuous image of > 10 min during diuretic renography. Out of them, a total of 16 nephroureteral systems in 12 children with scintigraphically abnormal ureter were analyzed. A diuretic washout index using response half time (t1/2) by linear fitting after lasix injection, was determined on renal (Kt1/2) and ureteral (Ut1/2) curves (diuretic renogram vs. diuretic ureterogram). Diuretic ureterogram curve patterns corresponding to normal (type I), obstructive (II) and non-obstructive (III) cases were described. Compared with X-ray data, diuretic renography was highly sensitive (88%) and specific (99%) for detecting any ureteral abnormality. Despite an obstructive Kt1/2 (>20 min), no patient with an abnormal ureter underwent therapy at the ureteropelvic junction because the hydronephrosis regressed after surgery at the lower level. Our data indicate that the abnormal ureter findings during diuretic renography have to be recognized before therapy for children with hydeonephrosis.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.279-290
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• 2005

Recently, as the serious damage caused by DDoS attacks increases, the rapid detection and the proper response mechanisms are urgent. However, existing security mechanisms do not effectively defend against these attacks, or the defense capability of some mechanisms is only limited to specific DDoS attacks. In this paper, we propose a detection architecture against DDoS attack using data mining technology that can classify the latest types of DDoS attack, and can detect the modification of existing attacks as well as the novel attacks. This architecture consists of a Misuse Detection Module modeling to classify the existing attacks, and an Anomaly Detection Module modeling to detect the novel attacks. And it utilizes the off-line generated models in order to detect the DDoS attack using the real-time traffic. We gathered the NetFlow data generated at an access router of our network in order to model the real network traffic and test it. The NetFlow provides the useful flow-based statistical information without tremendous preprocessing. Also, we mounted the well-known DDoS attack tools to gather the attack traffic. And then, our experimental results show that our approach can provide the outstanding performance against existing attacks, and provide the possibility of detection against the novel attack.

• Membrane Journal
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• v.9 no.4
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• pp.230-239
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• 1999

Perchlorate ion-selective electrodes in PVC membranes that respond linearly to concentration 106 M were developed by incorporating the quaternary phosphonium salts as a canier. The effects of the chemical structure, the contents of canier, the kind of plasticizer and the membrane thickness on electrode characteristics such as the electrode slope, the linear respone range and the detection limit were studied. With this results, the detectable pH range, selectivity coefficients and AC impedance characteristics were compared and investigated. The perchlorate ion substituents of the quaternary phosphonium salts like tetraoctylphosphonium perchlorate (TOPP) , tetraphenylphosphonium perchlorate(TPPP), and tetrabutylphosphonium perchlorate(TBPP) as a canier were used. The electrode characteristics were better in the ascending order of TBPP < TPPP < TOPP, with the increase of carbon chain length of the alkyl group. Dioctylsebacate(OOS) was best as a plasticizer, the canier contents were better with 11.76 wt% and the optimum membrane thickness was 0.19 mm. Under the above condition, the electrode slope was 56.58 mV/$^P{ClO}_4$,the linear response range was $10^{-1}$\times$10^{-6}$ M, the detection limit was 9.66 x $10^{-7}$ M. The performance of electrode was better than Orion electrode. The electrode potential was stable within the pH range from 3 to 11. The order of the selectivity coefficients for the perchlorate ion was sol < F < Br < 1. With the result of impedance spectrum, it was found that the equivalent circuit for the electrode could be expressed by a series combination of solution resistance, parallel circuit consisting of the double layer capacitance and bulk resistance and Warburg impedance. And solution resistance was almost not appeared and Warburg impedance was highly appeared by diffusion. Then Warburg coefficient was 1.32$\times$$10^74 $\Omega$ $\cdot$ ${cm}^2/s^{1/2}$.