• Structural Monitoring and Maintenance
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• 제6권3호
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• pp.255-268
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• 2019

Civil infrastructures, such as bridges and tunnels are most important assets and their failure during service will have significant economic and social impact in any country. Behavior of a bridge can be evaluated only through actual monitoring/measurements of bridge members under the loads of interest. Theoretical analysis alone is not a good predictor of the ability of a bridge. In some cases, theoretical analyses can give less effect than actual since theoretical analyses do not consider the actual condition of the bridge, support conditions, level of corrosion and damage in members and connections etc. Hence actual measurements of bridge response should be considered in making decisions on structural integrity, especially in cases of high value bridges (large spans and major crossings). This paper describes in detail the experimental investigations carried out on an open web type steel railway bridge. Strain gages and displacement transducers were installed at critical locations and responses were measured during passage of locomotives. Stresses were evaluated and extrapolated to maximum design loading. The responses measured from the bridge were within the permissible limits. The methodology adopted shall be used for assessing the structural integrity of the bridge for the design loads.

• Structural Engineering and Mechanics
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• 제91권3호
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• pp.279-289
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• 2024

The purpose of this study is to represent a useful alternative for the preliminary seismic vulnerability assessment of existing reinforced concrete buildings by introducing a statistical approach employing the binary logistic regression technique. Two different predictive statistical models, namely full and reduced models, were generated utilizing building characteristics obtained from the damage database compiled after 1999 Düzce earthquake. Among the inspected building parameters, number of stories, overhang ratio, priority index, soft story index, normalized redundancy ratio and normalized lateral stiffness index were specifically selected as the predictor variables for vulnerability classification. As a result, normalized redundancy ratio and soft story index were identified as the most significant predictors affecting seismic vulnerability in terms of life safety performance level. In conclusion, it is revealed that both models are capable of classifying the set of buildings being severely damaged or collapsed with a balanced accuracy of 73%, hence, both are able to filter out high-priority buildings for life safety performance assessment. Thus, in this study, having the same high accuracy as the full model, the reduced model using fewer predictors is proposed as a simple and viable classifier for determining life safety levels of reinforced concrete buildings in the preliminary seismic risk assessment.

• 대한약리학회지
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• 제32권3호
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• pp.335-345
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• 1996

허혈/재관류 뇌손상에서 활성산소류의 역할이 중요시되고 있다. 본 연구에서는 모래쥐의 총경동맥을 묶었다 풀어줌으로써 실험적 허혈/재관류 손상을 유도하고 산화성 스트레스 발생 유무와 이러한 산화성 스트레스가 세포손상으로 연결되는지를 알아보고자 하였다. 해마는 뇌조직 중에서도 특히 산화성 스트레스에 취약한 부분이므로 해마에서 얻은 조직을 대뇌피질에서 얻은 조직과 비교분석하였다. 또한, 이들 부위에서 heat shock protein 70(HSP70)의 발현이 허혈/재관류 손상에 미치는 영향도 검색하고자 하였다. 허혈/재관류에 의한 산화성 스트레스의 지표로써 글루타치온 산화정도, GSSG/(GSH+2xGSSG)를 측정하였을 때 주로 해마에서 산화지표가 상승됨을 관찰하였다. 한편 산화성 스트레스가 세포손상으로 연결되는지를 알아보고자 지질과산화물을 측정하였다. 두 부위 모두에서 지질과산화물 형성의 증가가 있었으며 대뇌피질에서보다 해마에서 더 증가됨을 알 수 있었다. 지질과산화물 형성의 정도나 시간적 변화양상이 글루타치온 산화의 그것들과 유사하였다. 이러한 결과들은 허혈/재관류에 의해 산화성 스트레스가 형성되며 동시에 이러한 산화성 스트레스가 세포 손상을 초래함을 보여준다. 또한 산화성 스트레스 및 산화성 세포손상 정도가 대뇌피질보다는 해마에서 더 큰 것을 알 수 있었다. 그러나, 피질과 해마에서 HSP70의 기초발현(basal level) 정도는 차이가 없었다. 이는 해마의 취약성이 HSP70 발현 결핍에 기인하지 않았음을 나타낸다. 반면 허혈/재관류에 의한 HSP70의 발현유도는 해마조직에서 제대로 이주어지지 않았고 northern blot결과 이는 전사단계에서의 부친에 의한 것으로 나타났다. 이러한 결과들로 볼 때 허혈/재관류에 의한 뇌손상에서 HSP70 유도정도를 측정하는 것이 세포의 취약성을 예측할 수 있는 지표로 유용하게 사용될 수 있을 것으로 사료된다.

• Journal of Chest Surgery
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• 제53권5호
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• pp.277-284
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• 2020

Background: Cardiac arrest during or after office-based cosmetic surgery is rare, and little is known about its prognosis. We assessed the clinical outcomes of patients who developed cardiac arrest during or after cosmetic surgery at office-based clinics. Methods: Between May 2009 and May 2016, 32 patients who developed cardiac arrest during or after treatment at cosmetic surgery clinics were consecutively enrolled. We compared clinical outcomes, including complications, between survivors (n=19) and non-survivors (n=13) and attempted to determine the prognostic factors of mortality. Results: All 32 of the patients were female, with a mean age of 30.40±11.87 years. Of the 32 patients, 13 (41%) died. Extracorporeal life support (ECLS) was applied in a greater percentage of non-survivors than survivors (92.3% vs. 47.4%, respectively; p=0.009). The mean duration of in-hospital cardiopulmonary resuscitation (CPR) was longer for the non-survivors than the survivors (31.55±33 minutes vs. 7.59±9.07 minutes, respectively; p=0.01). The mean Acute Physiology and Chronic Health Evaluation score was also higher among non-survivors than survivors (23.85±6.68 vs. 16.79±7.44, respectively; p=0.01). No predictor of death was identified in the patients for whom ECLS was applied. Of the 19 survivors, 10 (52.6%) had hypoxic brain damage, and 1 (5.3%) had permanent lower leg ischemia. Logistic regression analyses revealed that the estimated glomerular filtration rate was a predictor of mortality. Conclusion: Patients who developed cardiac arrest during or after cosmetic surgery at office-based clinics experienced poor prognoses, even though ECLS was applied in most cases. The survivors suffered serious complications. Careful monitoring of subjects and active CPR (when necessary) in cosmetic surgery clinics may be essential.

• Journal of Trauma and Injury
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• 제33권2호
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• pp.96-103
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• 2020

Purpose: In patients with trauma, rhabdomyolysis (RM) can lead to fatal complications resulting from muscle damage. Thus, RM must be immediately diagnosed and treated to prevent complications. Creatine kinase (CK) is the most sensitive marker for diagnosing RM. However, relying on CK tests may result in delayed treatment, as it takes approximately 1 hour to obtain CK blood test results. Hence, this study investigated whether the neutrophil-to-lymphocyte ratio (NLR) could predict RM at an earlier time point in patients with trauma, since NLR results can be obtained within 10 minutes. Methods: This retrospective study included 130 patients with severe trauma who were admitted to the emergency room of a tertiary institution between January 2017 and April 2020. RM was defined as a CK level ≥1,000 U/L at the time of arrival. Patients with severe trauma were categorized into non-RM and RM groups, and their characteristics and blood test results were analyzed. Statistical analysis was performed using SPSS version 26.0 for Windows. Results: Of the 130 patients with severe trauma, 50 presented with RM. In the multivariate analysis, the NLR (odds ratio [OR], 1.252; 95% confidence interval [CI], 1.130-1.386), pH level (OR, 0.006; 95% CI, 0.000-0.198), presence of acute kidney injury (OR, 3.009; 95% CI, 1.140-7.941), and extremity Abbreviated Injury Scale score (OR, 1.819; 95% CI, 1.111-2.980) significantly differed between the non-RM and RM groups. A receiver operating characteristic analysis revealed that a cut-off NLR value of 3.64 was the best for predicting RM. Conclusions: In patients with trauma, the NLR at the time of arrival at the hospital is a useful biochemical marker for predicting RM.

• Kidney Research and Clinical Practice
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• 제37권4호
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• pp.338-346
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• 2018

Background: The most common cause of acute kidney injury (AKI) in pregnancy is preeclampsia. Serum cystatin C (CysC) is a potential biomarker of early kidney damage as its levels are not disturbed by volume status changes in pregnancy, and serum CysC levels could serve as a replacement for conventionally used creatinine. In this study, we investigated the serum levels of CysC in severe preeclampsia cases and the associations between CysC levels and poor obstetric outcomes. Methods: Our cohort included severe preeclampsia patients with a normal serum creatinine level. Creatinine was measured to calculate estimated glomerular filtration rate (eGFR) based on the Cockcroft and Gault, Modification of Diet in Renal Disease Study (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, while CysC was measured to calculated eGFR based on a CysC-based equation. We then evaluated the correlations between serum CysC level, eGFR, and obstetric outcomes. Results: Twenty-six patients were evaluated of which 38.5% delivered preterm and 30.8% had low-birth weight babies. Unlike creatinine-based eGFR and CysC-based eGFR, serum CysC demonstrate significant negative correlation with gestational age. Receiver operating characteristic curve analysis indicated that serum CysC is a potential biomarker of preterm delivery with a cut-off serum level of 1.48 mg/L with 80% sensitivity and 75% specificity. Conclusion: GFR estimation using CysC is likely to be inaccurate in pregnancy. However, we found a significant correlation between preterm delivery and serum CysC level. Our results suggest that serum CysC level has the potential to predict preterm delivery in severe preeclampsia patients.

• 환경위생공학
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• 제7권2호
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• pp.95-110
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• 1992

Much progress has been made in understanding the subcellular events of the human lung injuries after acute exposure to environmental air pollutants. Host of those events represent oxidative damages mediated by reactive oxygen species such as superoxide, hydrogen peroxide, and the hydroxy, free radical. Recently, nitric oxide (NO) was found to be endogenously produced by endothelial cells and cells of the reticulo-endothelial system as endothelialderived relaxation factor (EDRF) which is a vasoactive and neurotransmitter substance. Together with superoxide, NO can form another strong oxidant, peroxonitrite. The relative importance of exogenous sources of $N0/N0_2$ and endogenous production of NO by the EDRF producing enzymes in the oxidative stresses to the heman lung has to be elucidated. The exact events leading to chronic irreversible damage are still yet to be known. From chronic exposure to oxidant gases, progressive epithelial and interstitial damages develop. Type I epithelial cells become thicker and cover a smaller average alveolar surface area while thee II cells proliferate instead. Under acute damages, the extent of loss of the alveolar epithelial cell lining, especially type II cells appears to be a good predictor of the ensuing irreversible damage to alveolar compartment. Interstitial matrix undergo remodeling during chronic exposure with increased collagen fibers and interstitial fibroblasts. However, Inany of these changes can be reversed after cessation of exposure. Among chronic lung injuries, genetic damages and repair responses received particular attention in view of the known increased lung cancer risks from exposure to several air pollutants. Heavy metals from foundry emission, automobile traffics, and total suspended particulate, especially polycystic aromatic hydrocarbons have been positively linked with the development of lung cancer. Asbestos in another air pollutant with known risk of lung cancer and mesothelioma, but asbestos fibers are nonauthentic in most bioassays. Studies using the electron spin resonance spin trapping method show that the presence of iron in asbestos accelerates the production of the hydroxy, radical in vitro. Interactions of these reactive oxygen species with particular cellular components and disruption of cell defense mechanisms still await further studies to elucidate the carcinogenic potential of asbestos fibers of different size and chemical composition. The distribution of inhaled pollutants and the magnitude of their eventual effects on the respiratory tract are determined by pollutant-independent physical factors such as anatomy of the respiratory tract and level and pattern of breathing, as well as by pollutant-specific phyco-chemical factors such as the reactivity, solubility, and diffusivity of the foreign gas in mucus, blood and tissue. Many of these individual factors determining dose can be quantified in vitro. However, mathematical models based on these factors should be validated for its integrity by using data from intact human lungs.

• 대한임상검사과학회지
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• 제38권3호
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• pp.208-211
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• 2006

Microalbuminuria is most frequently caused by kidney damage from diabetes. Moreover, many other conditions can lead to kidney damage, such as high blood pressure, heart failure, cirrhosis, or systemic lupus erythematosus (SLE). The measurement of the microalbumin in urine may be useful for the early diagnosis or as a predictor of nephropathy in diabetes. The most common method for getting a quantitative measurement of urinary protein relies on a 24-hour urine collection. The result of this method is accurate. But 24hr urine collection is difficult to obtain and variations in volume are frequent. Also the patients complain about urine collection. We tried to measure reference values for microalbumin using fasting urine and compare them with the albumin/creatinine ratio using 24hr urine. The concentrations of microalbumin in fasting urine and 24hr urine were $7.1{\pm}3.8mg/L$, $5.7{\pm}2.9mg/L$ (r=0.61, p=0.27), respectively. The albumin/creatinine ratios using fasting urine and 24hr urine were $8.7{\pm}4.2{\mu}g/mg$, $8.7{\pm}4.0{\mu}g/mg$ (r=0.76, p=0.88), respectively. This study indicated that the measurement of microalbumin in fasting urine was an easy and simple method for early diagnosis or to predict nephropathy in diabetes. Thus, setting up the reference value using fasting urine may be useful in the screening test for the diabetic nephropathy patients instead of using the 24hr albumin excretion rate (AER).

• Childhood Kidney Diseases
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• 제3권1호
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• pp.72-79
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• 1999

서 론 : 방광요관역류로 인한 신조직의 손상은 소아에서 말기신부전 및 신성 고혈압의 중요한 원인중 하나이며 방광요관역류에 의한 신장변화는 조기에 발견될 경우 그 예방이 가능하다. 현재까지는 주로 반복적이며 항생제 치료에 잘 조절되지 않는 요로감염에서 방광요관역류를 의심하고 진단을 위한 방사선학적 진단법을 시행하였으나, 단발성의 요로감염 환아에서도 역류가 진행되어있는 경우를 경험하게 되므로, 요로감염이 있는 환아에서 방광요관역류를 조기에 의심할 수 있는 진단방법이 요구되고 있다. 본 연구에서는 요로감염이 있는 환아를 대상으로하여 방광요관역류가 있는 군과 방광요관역류가 없는 군에서 뇨중 ${\beta}_2$-microglobulin(${\beta}_2$-MG)을 측정하여 의미있는 차이가 있는지를 알아보고 그 차이가 요로감염이 진행중인 환아에서 방광요관역류의 존재의 지표로 이용될 수 있는지 여부를 확인하고자 하였다. 대상 및 방법 : 요로감염으로 처음 내원하여 치료를 시작하였던 57명의 환아를 대상으로 하였으며, 전례에서 방사선학적인 검사(복부초음파, DMSA scan 및 VCUG)를 시행하여, 단순 요로감염환아군과 요로감염이 있으면서 방광요관역류가 발견되었던 환아군으로 구분하였고, 각 군간의 무작위 추출 뇨중 ${\beta}_2$-MG치와 뇨중 creatinine치의 비율로 그 배설율을 비교하였다. 대상환아중 신독성 약물을 사용하였던 환아 및 ${\beta}_2$-MG의 생성 및 배출에 영향을 미칠 수 있는 질환을 앓고있는 환아는 본 연구에서 제외하였다. 결 과 : 전체 대상환아 57명중 남녀비는 28:29였고 평균연령은 $4.27{\pm}4.24$세 였다 요로감염이 배양검사상 확진된 례가 44례 였고, 임상적으로 요로감염이 의심되었던 례가 13례 였으며 배양된 균주는 E.coli($43.9\%$)와 Enterococcus($15.8\%$)가 가장 많았다. 방광요관역류는 12례($21.1\%$)에서 발견되었으며 평균연령은 $2.97{\pm}2.82$세로 단순 요로감염 환아군의 평균연령 $4.62{\pm}4.51$세에 비하여 낮은 경향을 보였고, 남녀비는 3:1로 남아가 많았다. 무작위 추출뇨중 평균 ${\beta}_2$-MG치는 단순 요로감염군 $0.19{\pm}0.16mg/dL$, 방광요관역류군 $2.2{\pm}5/91,g/dL$로 두군간에 의미있는 차이를 보였으며(P=0.03), ${\beta}_2$-MG/creatinine비는 단순 요로감염군은 $3.93{\pm}3.44$, 방광요관역류동반군은 $32.41{\pm}25.7$로 두군간에 의미있는 차이를 나타내었다(P=0.007). 두군간의 배양된 균주 및 균배양 양성율과 혈청 크레아틴치의 의미있는 차이는 없었다. 결 론 : 요로감염환자에서 무작위 추출뇨중 ${\beta}_2$-MG치와 배설율은 방광요관역류의 존재를 조기에 의심할 수 있게하는 검사법이며, 기존의 24시간뇨를 이용하여 측정하는 방법보다 간편하고 비용이 저렴하여 방광요관역류의 검색진단법으로서 유용하리라 생각되며 소아 고혈압과 말기신부전의 원인 질환중 많은 부분을 차지하고 있는 방광뇨관역류의 조기진단 및 조기치료로 그 이행율을 감소시키는데 많은 기여를 할 수 있을 것으로 기대된다.

• 대한두경부종양학회지
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• 제22권1호
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• pp.8-14
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• 2006

Objectives: The p53 tumor suppressor gene has a key role in cellular control mechanisms involving apoptosis and DNA repair, leading to the G1 arrest following DNA damage. Its mutation is one of the most frequent alterations in human cancers. Ki-67 is identified in replicating cells of both benign and malignant lesions, so it can be the predictor of proliferative activity. The aim of this study is to evaluate the expression of p53 and Ki-67 in salivary gland tumors. Materials and Methods: Immunohistochemical analysis was used to detect expression of p53 and Ki-67 in paraffin-embedded samples from 31 benign and 27 malignant salivary gland tumors. Results were analyzed between benign and malignant tumors and compared with the clinical parameters such as stage and recurrence in malignant tumors. Results: p53 overexpression was detected in 19.6% of benign tumors and 40.7% of malignant tumors, but there was no statistical significance. p53 was significantly expressed in Warthin's tumor(45.5%) compared with pleomorphic adenoma(5.9%). Only 5.9% of pleomorphic adenoma were positive for p53, while 60% of carcinoma ex pleomorphic adenoma were positive for p53. Ki-67 was expressed in 3.2% of benign tumors and 51.9% of malignant tumors, which showed significant higher expression in malignant tumors. In malignant tumors, p53 and Ki-67 expressions bore no correlation to stage and recurrence. Conclusion: p53 overexpression is not associated with the progression of malignant tumors, and Ki-67 overexpression can be used as biologic indicator of malignant salivary gland tumors.