• Structural Monitoring and Maintenance
• /
• v.6 no.3
• /
• pp.255-268
• /
• 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
• /
• v.91 no.3
• /
• pp.279-289
• /
• 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.

• The Korean Journal of Pharmacology
• /
• v.32 no.3
• /
• pp.335-345
• /
• 1996

A critical role of oxygen-derived free radicals has been implicated in ischemia/reperfusion (I/R)-induced brain damage. In this study, we have produced experimental I/R to the brains of Mongolian gerbil (Meriones unguiculatus) by a transient occlusion and release of the common carotid arteries. We have attempted to determine whether the oxidative stress is generated upon I/R and whether this oxidative stress is linked to the cell damage. Since hippocampus has been suggested as one of the most vulnerable regions of the brain to the oxidative stress, we analyzed samples from hippocampus in comparison with those from cortex. In addition, we have examined the expression of heat shock protein 70kD species (HSP70) in these regions in order to evaluate a possible role of this protein in I/R-induced brain damage. To determine whether the oxidative stress is produced upon I/R, we measured the glutathione oxidation, GSSG/ (GSH + 2xGSSG), as an index of oxidative stress. We found an increase of the glutathione oxidation primarily in hippocampus upon I/R. To determine whether this oxidative stress is linked to the cell damage, we measured the degree of lipid peroxidation upon I/R. We found an increase of lipid peroxidation in both regions. However, the magnitude of increases was greater in hippocampus than in cortex. In addition, we found that changes in both the magnitude and the temporal patterns of glutathione oxidation closely correlated with those of lipid peroxidation. Our study provides biochemical evidences that the oxidative stress is generated upon I/R and this oxidative stress is linked to the oxidative cell damage. Our study also provides evidences that the degree of oxidative stress as well as oxidative cell damage is greater in hippocampus than in cortex. We could not find difference in the basal level of HSP70 expression between hippocampus and cortex, indicating that the intrinsic vulnerability of hippocampus cannot be explained by the lower level of HSP70 expression. We did find, however, that the induction of HSP70 expression upon I/R was impaired in the hippocampus. This impairment appeared to be at the transcriptional level. These results suggest that the measurement of HSP70 induction may be employed as a useful predictor of differential cellular susceptibilities to the I/R-induced brain damage.

• Journal of Chest Surgery
• /
• v.53 no.5
• /
• pp.277-284
• /
• 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
• /
• v.33 no.2
• /
• pp.96-103
• /
• 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
• /
• v.37 no.4
• /
• pp.338-346
• /
• 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.

• Journal of environmental and Sanitary engineering
• /
• v.7 no.2
• /
• pp.95-110
• /
• 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.

• Korean Journal of Clinical Laboratory Science
• /
• v.38 no.3
• /
• pp.208-211
• /
• 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
• /
• v.3 no.1
• /
• pp.72-79
• /
• 1999

Renal scarring associated with vesico-ureteral reflux(VUR) is one of the major causes of end stage renal failure and renal hypertension in children. Urinary ${\beta}_2$-microglobulin(MG) has been suggested as a potential marker for presence of renal tubular damage. This study was designed to evaluate the significance of random urine ${\beta}_2$-MG as a predictor of presence of vesico-ureteral reflux in children with urinary tract infection(UTI). 57 children with urinary tract infection were studied. Patients were devided into two groups; 35($78.9\%$) children have UTI without VUR and 12($21.1\%$) children have UTI and VUR. Beta2-MG and creatinine in random urine sample was measured to decide the excretion ratio(${\beta}_2$-MG/creatinine). Among the 57 children with UTI, 44 children were confirmed by urine culture study and 13 children suspected by compatible clinical feature. Random urine ${\beta}_2$-MG of VUR group ($2.2{\pm}5.91$ mg/L) were significantly higher than that of simple UTI group($0.19{\pm}0.16mg/L$)(P=0.03). The ${\beta}_2$-MG/creatinine ratio of VUR group($32.41{\pm}25.7$) were significantly higher than that of simple UTI group($3.93{\pm}3.44$)(P=0.007). In conclusion, random urine ${\beta}_2$-MG and excretion ratio deserved early predictor of presence of VUR in children with UTI. And this method was more simple and inexpensive than the method of measuring ${\beta}_2$-MG with 24 hour urine collection, so might be a useful screening test for VUR in children with UTI.

• Korean Journal of Head & Neck Oncology
• /
• v.22 no.1
• /
• pp.8-14
• /
• 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.