• Pediatric Infection and Vaccine
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• v.23 no.2
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• pp.117-127
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• 2016

Purpose: Vaccine evaluation studies were initiated from 2000 by the Ministry of Food and Drug Safety to produce proper data about the safety and immunogenicity of vaccines. The purpose of this study was to review studies and reports on evaluation of vaccine such as immunogenicity, efficacy, effectiveness, safety and other related topics in order to find and analyze the data on the usefulness of each vaccine. Methods: From 2000 to 2014, the project "The vaccine evaluation" had been performed by several researchers, and studies and reports of vaccine evaluation. We reviewed the results and outcomes of studies regarding the evaluation of vaccine's usefulness and analyzed the possibilities of applying these data for establishing vaccine policies. For each vaccine, data analysis and organization were done according to evaluation fields. Results: A total of 83 studies were performed on vaccines from 2000 to 2014. For each vaccine, 8 studies were performed on BCG, 14 on DTaP/Td, 1 on poliovirus, 5 on Hib, 3 on pneumococcus, 11 on influenza, 3 on hepatitis A, 11 on MMR, 11 on varicella, and 16 on Japanese encephalitis. All studies were analyzed by the following evaluation area, such as safety, immunogenicity, seroprevalence, persistence of immunity, efficacy, effectiveness, vaccine evaluation methods, quality control product for vaccine, and others. Conclusions: Vaccine evaluation studies performed in Korea may be useful as references for establishing vaccination strategy and policy and could be used as baseline data for future studies on vaccine evaluation, vaccine policy establishment, and public/expert vaccine education in Korea.

• Pediatric Infection and Vaccine
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• v.24 no.1
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• pp.44-53
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• 2017

Purpose: The aim of this study was to investigate the risk factors for posttransplant lymphoproliferative disorder (PTLD) and to evaluate the association between Epstein-Barr viral load and the development of PTLD in pediatric heart transplant recipients. Methods: We reviewed children aged <18 years who underwent heart transplantation and quantitative analysis of blood Epstein-Barr virus (EBV) viremia at our institute from January 2006 to March 2015. Clinical characteristics and EBV viral loads were compared according to the presence of PTLD. Results: Over 9 consecutive years, a total of 40 heart transplant recipients, were included. Among 28 children with available EBV viral load measurements, seven patients (25%) had EBV viremia only defined as at least one time of ${\geq}457copies/mL$. PTLD occurred in three recipients (7.5%) 4.3, 6.3, and 17.0 months after transplant and all PTLD cases had preceding EBV viremia. The median age at transplant was 5.3 years (range, 0.5 to 6.0 years) in the PTLD group, compared with 11.9 years (range, 0.3 to 17.8 years) in the non-PTLD group (P=0.021). The median values of the peak EBV levels in the PTLD group were 3,452,170 copies/mL (range, 46,750 to 7,622,910 copies/mL); the peak EBV levels in the non-PTLD group were 3,112 copies/mL (range, 2,250 to 103,000 copies/mL). Conclusions: Younger age at transplant and presence of EBV viremia were associated with the development of PTLD in pediatric heart transplant recipients. A prospective study will be required to determine the blood EBV load for predicting the development of PTLD in these patients.

• Pediatric Infection and Vaccine
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• v.24 no.3
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• pp.146-151
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• 2017

Purpose: We analyzed the risk factors affecting readmission of children with pneumonia. Methods: We retrospectively analyzed the medical records of pediatric patients admitted to the Department of Pediatrics at the Jeonju Presbyterian Medical Center from January 2007 to August 2016. We classified patients who were readmitted with pneumonia within 30 days of discharge as the readmission group and patients who were admitted with pneumonia for the first time as the first admission group. Results: Among 158 patients, the study (readmission) group included 82 patients and the control (first admission) group included 76 patients. Age, the percentage of segmented neutrophils and lymphocytes, the number of admissions in the last 12 months, the associated diseases (respiratory diseases such as asthma), and the affection of the right upper lung were analyzed as risk factors for readmission. However, based on a regression analysis, only age and associated diseases were found to be significant risk factors. The rate of readmission increased with younger age. When there were associated diseases, the rate of readmission also increased. Conclusions: Young age and associated diseases were significant risk factors for readmission for patients with pediatric pneumonia. When pediatric patients are admitted with pneumonia, if they are young and/or have associated diseases, a comprehensive approach is needed to reduce the rate of readmission with careful consideration of precise examination, treatment, timing of discharge, and follow-up.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.324-333
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• 2013

Recently, rudder erosion due to cavitation has been frequently reported on a semi-spade rudder of a high-speed large ship. This problem raises economic and safety issues when operating ships. The semi-spade rudders have a gap between the horn/pintle and the movable wing part. Due to this gap, a discontinuous surface, cavitation phenomenon arises and results in unresolved problems such as rudder erosion. In this study, we made a rudder model for 2-D experiments using the NACA0020 and also manufactured gap flow blocking devices to insert to the gap of the model. In order to study the gap flow characteristics at various rudder deflection angles($5^{\circ}$, $10^{\circ}$, $35^{\circ}$) and the effect of the gap flow blocking devices, we carried out the velocity measurements using PIV(Particle Image Velocimetry) techniques and cavitation observation using high speed camera in Seoul National University cavitation tunnel. To observe the gap cavitation on a semi-spade rudder, we slowly lowered the inside pressure of the cavitation tunnel until cavitation occurred near the gap and then captured it using high-speed camera with the frame rate of 4300 fps(frame per second). During this procedure, cavitation numbers and the generated location were recorded, and these experimental data were compared with CFD results calculated by commercial code, Fluent. When we use gap flow blocking device to block the gap, it showed a different flow character compared with previous observation without the device. With the device blocking the gap, the flow velocity increases on the suction side, while it decreases on the pressure side. Therefore, we can conclude that the gap flow blocking device results in a high lift-force effect. And we can also observe that the cavitation inception is delayed.

• Molecules and Cells
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• v.39 no.6
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• pp.468-476
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• 2016

PLZF-expressing invariant natural killer T cells and CD4 T cells are unique subsets of innate T cells. Both are selected via thymocyte-thymocyte interaction, and they contribute to the generation of activated/memory-like CD4 and CD8 T cells in the thymus via the production of IL-4. Here, we investigated whether $PLZF^+$ innate T cells also affect the development and function of $Foxp3^+$ regulatory CD4 T cells. Flow cytometry analysis of the thymus and spleen from both CIITA transgenic C57BL/6 and wild-type BALB/c mice, which have abundant $PLZF^+$ CD4 T cells and invariant natural killer T cells, respectively, revealed that $Foxp3^+$ T cells in these mice exhibited a $CD103^+$ activated/memorylike phenotype. The frequency of $CD103^+$ regulatory T cells was considerably decreased in $PLZF^+$ cell-deficient $CIITA^{Tg}Plzf^{lu/lu}$ and $BALB/c.CD1d^{-/-}$ mice as well as in an IL-4-deficient background, such as in $CIITA^{Tg}IL-4^{-/-}$ and $BALB/c.IL-4^{-/-}$ mice, indicating that the acquisition of an activated/ memory-like phenotype was dependent on $PLZF^+$ innate T cells and IL-4. Using fetal thymic organ culture, we further demonstrated that IL-4 in concert with TGF-${\beta}$ enhanced the acquisition of the activated/memory-like phenotype of regulatory T cells. In functional aspects, the activated/ memory-like phenotype of Treg cells was directly related to their suppressive function; regulatory T cells of $CIITA^{Tg}PIV^{-/-}$ mice more efficiently suppressed ovalbumin-induced allergic airway inflammation compared with their counterparts from wild-type mice. All of these findings suggest that $PLZF^+$ innate T cells also augmented the generation of activated/memory-like regulation via IL-4 production.

• Pediatric Infection and Vaccine
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• v.25 no.1
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• pp.8-16
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• 2018

Purpose: In this study, the clinical and epidemiological characteristics of patients admitted for viral croup were analyzed to evaluate disease severity based on the organism that caused the infection. Methods: We retrospectively reviewed the medical records of 302 patients who were admitted to the Department of Pediatrics at the Wonju Severance Hospital between May 2013 and December 2016 for viral croup. Patients who showed positive results on multiplex polymerase chain reaction were subsequently diagnosed with respiratory virus infection. The Westley scoring system was used to evaluate the severity of viral croup. Results: Of the 302 patients, 149 were admitted due to severe viral croup, including 88 boys and 61 girls, with a boy-to-girl ratio of 1.44:1. About 110 cases of parainfluenza virus infection have been reported, which accounted for almost half of the total cases. The other identified viruses included influenza virus, human rhinovirus, and respiratory syncytial virus. Analysis of the association between severe viral croup and causative pathogen revealed that only parainfluenza type 2 virus showed a significantly high risk. Parainfluenza type 2 virus did not show an age-based difference in frequency but showed relatively a higher frequency of infections during the summer and fall. Conclusions: In this study, parainfluenza virus type 2 was the only virus associated with severe viral croup. To facilitate proper preventive management, treatment, and prognosis evaluation of viral croup, prospective and multicenter studies should assess the additional variables and the severity of the virus. Additionally, further studies should be conducted to assess age-dependent influences, as well as the regional and seasonal incidence of viral infection.

• Pediatric Infection and Vaccine
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• v.24 no.2
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• pp.87-94
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• 2017

Purpose: The inappropriate prescription of antibiotics in children with upper respiratory tract infection (URTI) is common. This study evaluated the factors that influence antibiotics use in hospitalized children with viral URTI confirmed by reverse transcriptase-polymerase chain reaction (RTPCR) assay. Methods: The medical records of admitted patients who performed RT-PCR assay for respiratory virus pathogens from January 2013 to November 2014 were examined. The demographic and clinical features were compared between patients who were administered antibiotics at admission and those who were not. We also investigated differences between children who continued antibiotics and those who stopped antibiotics after a viral pathogen was identified. Results: In the total 393 inpatients, the median age was 23 months (interquartile range, 13 to 41.3 months). Antimicrobial agents were prescribed in 79 patients (20.1%) at admission. Patients with acute otitis media (AOM) had higher rates of antibiotics prescription than those without AOM (48.1% vs. 2.2%, P<0.001), with an adjusted odds ratio of 91.1 (95% confidence interval, 30.5 to 271.7). Level of high-sensitivity C-reactive protein and the proportion of acute rhinosinusitis were also significantly associated with antibiotics use (P<0.001). Among the 44 patients with viruses identified using the RT-PCR method during hospitalization, antibiotic use was continued in 28 patients (63.6%). AOM was statistically associated with continued antibiotic use in the patients (P=0.002). Conclusions: Although the respiratory virus responsible for URTI etiology is identified, clinicians might not discontinue antibiotics if AOM is accompanying. Therefore, careful diagnosis and management of AOM could be a strategy to reduce unjustified antibiotic prescriptions for children with URTI.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.480-480
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• 2018

전 세계적으로 자연 친화, 하천생태계 보전, 친수하천 등을 조성하기 위한 대대적인 하천 정비사업이 활발히 진행 중에 있다. 최근 홍수로 인한 제방 붕괴에 대응하기 위한 제방의 안정화 및 개선을 위한 방법으로 기존의 시멘트와 같은 혼합물질을 사용하지 않고 환경 친화적이고 지속 가능한 대안에 대한 수요가 증가되고 있는 추세이며 현재 노후화 된 불안정 제방에 대한 보강대책을 수립해나가는 과정으로써 친환경 신소재를 활용하여 제방을 보호하는 연구가 수행되고 있다. 제방사면에 적용되는 신소재는 바이오폴리머를 활용한 재료로써 공동연구기관 카이스트에서 개발된 환경 친화적인 물질로 미생물에 의해 유도된 고인장 및 인체 무해성 등의 특성을 갖고 있으며 경제적 타당성인 측면에서 시멘트와 비교 분석 되어야 하고 실제 현장에서의 적용 가능성, 신뢰성 및 내구성 검토 등 성능을 보장하기 위한 지속적인 연구가 필요한 상황이다. 이에 본 안동하천실험센터에서는 중규모 제방을 직접 제작하여 수리모형실험을 통한 친환경 신소재 활용 제방의 안정성 및 성능 평가를 실시하였다. 수리실험 조건은 카이스트에서 제시된 레시피를 기반으로 먼저 분말형태의 바이이폴리머를 물과 희석하여 만들어진 바이오폴리머 용액을 흙과 혼합한 뒤 제방표면에 직접 미장작업을 수행하여 실험조건에 따라 일정한 두께(1cm, 3cm, 5cm)로 피복하였다. 이후 월류 붕괴 실험이 가능한 3 - 5일 정도의 양생기간을 거쳐 실험을 진행하였다. 실험결과는 다수의 고프로(GoPro) 및 비디오 카메라 등 다양한 영상장치를 이용하여 픽셀기반의 영상분석기법을 활용한 시간 흐름에 따른 제방 사면에서의 붕괴규모를 산정하여 신소재의 피복 두께에 따른 제체의 붕괴 거동 및 안정성을 평가하였으며, 또한 제방 파괴부에서의 흐름 상황 및 유속이 붕괴 발달에 미치는 영향을 분석하기 위하여 PIV 분석을 실시하였다. 이번 연구의 최종목표는 지속적인 예비실험을 수행하여 월류 및 침투, 파이핑 등 파괴 인자 별 신소재의 성능 개선 및 개발된 새로운 공법에 대한 효과 검토를 통한 최적안을 도출함으로써 향후 실규모 실험실증을 통한 신소재 시공 및 공법에 대한 현장적용 가능성 검증을 거쳐 최종적으로 신소재 제방 공법 설계 기술, 신소재 및 공법 표준안, 제방공법 안정성 평가 가이드라인 등을 제시하고자 하며, 이러한 실험데이터를 축적함으로써 실제 제방 붕괴 시 비상대처계획 수립에 필요한 기초자료로 활용이 가능할 것으로 사료된다.

• Pediatric Infection and Vaccine
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• v.25 no.3
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• pp.141-147
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• 2018

Purpose: Despite effectiveness and safety of maternal tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination, Tdap vaccination coverage during pregnancy remains quite low. We assessed the knowledge, attitude and practice on maternal Tdap vaccination among pregnant women. Methods: This study was a cross-sectional survey of pregnant women who visited tertiary obstetrics and gynecologic units in Seoul and Gyeonggi province of Korea. Individual questionnaires were administered to assess knowledge, attitude and practice on maternal immunization with Tdap. Results: The questionnaires were completed by 184 pregnant women; 158 (86%) had not received information from doctors about pertussis and Tdap, and 166 (90%) did not know the need for Tdap vaccination. Only 7% of pregnant women unlikely to receive Tdap vaccine during current pregnancy answered 3 or more of the 5 knowledge-based questions correctly. By logistic regression analysis, recommendation by doctor (adjusted odd ratio [OR], 236.2; 95% confidence interval [CI], 12.6-4,432), belief that the vaccine is effective (adjusted OR, 40.21; 95% CI, 2.35-687.7), and belief that the vaccine is safe (adjusted OR, 19.83; 95% CI, 1.54-255.9) were significantly important factors to respondents' intention to be vaccinated. Conclusions: Most pregnant women seem to be neither recommended nor adequately informed about Tdap vaccination. Information given by health care professionals is very important to increase Tdap coverage among pregnant women.

• Pediatric Infection and Vaccine
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• v.26 no.1
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• pp.51-59
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• 2019

Purpose: The aim of this study was to evaluate the relationships between cytokine and chemokine levels and the clinical severity of Mycoplasma pneumoniae pneumonia. Methods: A retrospective analysis of clinical and laboratory parameters were performed. Serum levels of interleukin (IL)-6, IL-8, IL-10, IL-18, interferon-${\gamma}$-inducible protein-10 (IP-10), macrophage inflammatory $protein-1{\beta}$, and tumor necrosis $factor-{\alpha}$ were measured. The severity of patients' clinical course and radiologic findings were also assessed. Results: Seventy-two patients (35 males and 37 females) with a median age of 3.9 years (range, 1-16 years) were enrolled. Patients with lobar pneumonia (n=29) had significantly higher C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and IL-18 values than those with broncho-interstitial pneumonia (n=43). However, the cytokine and chemokine values did not differ between the group that was treated with corticosteroids (n=31) and the one that was not (n=41). The CRP, ESR, lactate dehydrogenase (LDH), IL-18, and IP-10 values showed positive correlations with fever duration prior to admission. The CRP and ESR values were positively correlated with IL-18, and LDH, with IP-10 levels. Conclusions: CRP, ESR, LDH, IL-18, and IP-10 values were associated with the severity of the disease, manifesting lobar pneumonia or prolonged fever duration prior to admission.