• Structural Engineering and Mechanics
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• v.75 no.5
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• pp.607-620
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• 2020

A numerical study is carried out to assess the dynamic response and damage level of one- and two-way reinforced concrete (RC) panels subjected to explosive loads by using finite element LS-DYNA software. The precision of the numerical models is validated with the previous experimental test. The calibrated models are used to conduct a series of parametric studies to evaluate the effects of panel wall dimensions, concrete strength, and steel reinforcement ratio on the blast-resistant capacity of the panel under various magnitudes of blast load. The results are used to develop pressure-impulse (P-I) diagrams corresponding to the damage levels defined according to UFC-3-340-02 manual. Empirical equations are proposed to easily construct the P-I diagrams of RC panels that can be efficiently used to assess its safety level against blast loads.

• Journal of the Korean Geotechnical Society
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• v.25 no.6
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• pp.59-72
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• 2009

The load distribution and deflection of offshore piles are investigated by lateral load-transfer curve method (p-y curve). Special attention is given to the soil-pile interaction and soil resistance of 3D wedge failure mode. A framework for determining a hyperbolic p-y curve is proposed based on theoretical analysis and experimental load test results. The methods for determining appropriate material parameters needed for constructing the proposed p-y curves are presented in this paper. Through comparisons with field case studies, it was found that the proposed method in the present study estimates reasonably the load transfer behavior of pile, and thus, the computed pile responses, such as bending moment and lateral displacement, agree well with the actual measured responses.

• Biomedical Science Letters
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• v.11 no.2
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• pp.129-134
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• 2005

Three different deconvolution techniques for quantifying cerebral blood flow (CBF) from whole brain $T2^{\ast}-weighted$ bolus tracking images were implemented (parametric Fourier transform P-FT, parametric single value decomposition P-SVD and nonparametric single value decomposition NP-SVD). The techniques were tested on 206 regions from 38 hyperacute stroke patients. In the P-FT and P-SVD techniques, the tissue and arterial concentration time curves were fit to a gamma variate function and the resulting CBF values correlated very well $(CBF_{P-FT}\;=\;1.02{\cdot}CBF_{p-SVD},\;r^2\;=\;0.96)$. The NP-SVD CBF values correlated well with the P-FT CBF values only when a sufficient number of time series volumes were acquired to minimize tracer time curve truncation $(CBF_{P-FT}\;=\;0.92{\cdot}CBF_{NP-SVD},\;r^2\;=\;0.88)$. The correlation between the fitted CBV and the unfitted CBV values was also maximized in regions with minimal tracer time curve truncation $(CBV_{fit}\;=\;1.00{\cdot}CBV_{ Unfit},\;^r^2\;=\;0.89)$. When a sufficient number of time series volumes could not be acquired (due to scanner limitations) to avoid tracer time curve truncation, the P-FT and P-SVD techniques gave more reliable estimates of CBF than the NP-SVD technique.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4603-4608
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• 2015

Background: To determine the potential value of serum tumor markers in predicting pCR (pathological complete response) during neoadjuvant chemotherapy. Materials and Methods: We retrospectively monitored the pro-, mid-, and post-neoadjuvant treatment serum tumor marker concentrations in patients with locally advanced breast cancer (stage II-III) who accepted pre-surgical chemotherapy or chemotherapy in combination with targeted therapy at Fudan University Shanghai Cancer Center between September 2011 and January 2014 and investigated the association of serum tumor marker levels with therapeutic effect. Core needle biopsy samples were assessed using immunohistochemistry (IHC) prior to neoadjuvant treatment to determine hormone receptor, human epidermal growth factor receptor 2(HER2), and proliferation index Ki67 values. In our study, therapeutic response was evaluated by pCR, defined as the disappearance of all invasive cancer cells from excised tissue (including primary lesion and axillary lymph nodes) after completion of chemotherapy. Analysis of variance of repeated measures and receiver operating characteristic (ROC) curves were employed for statistical analysis of the data. Results: A total of 348 patients were recruited in our study after excluding patients with incomplete clinical information. Of these, 106 patients were observed to have acquired pCR status after treatment completion, accounting for approximately 30.5% of study individuals. In addition, 147patients were determined to be Her-2 positive, among whom the pCR rate was 45.6% (69 patients). General linear model analysis (repeated measures analysis of variance) showed that the concentration of cancer antigen (CA) 15-3 increased after neoadjuvant chemotherapy in both pCR and non-pCR groups, and that there were significant differences between the two groups (P=0.008). The areas under the ROC curves (AUCs) of pre-, mid-, and post-treatment CA15-3 concentrations demonstrated low-level predictive value (AUC=0.594, 0.644, 0.621, respectively). No significant differences in carcinoembryonic antigen (CEA) or CA12-5 serum levels were observed between the pCR and non-pCR groups (P=0.196 and 0.693, respectively). No efficient AUC of CEA or CA12-5 concentrations were observed to predict patient response toward neoadjuvant treatment (both less than 0.7), nor were differences between the two groups observed at different time points. We then analyzed the Her-2 positive subset of our cohort. Significant differences in CEA concentrations were identified between the pCR and non-pCR groups (P=0.039), but not in CA15-3 or CA12-5 levels (p=0.092 and 0.89, respectively). None of the ROC curves showed underlying prognostic value, as the AUCs of these three markers were less than 0.7. The ROC-AUCs for the CA12-5 concentrations of inter-and post-neoadjuvant chemotherapy in the estrogen receptor negative HER2 positive subgroup were 0.735 and 0.767, respectively. However, the specificity and sensitivity values were at odds with each other which meant that improving either the sensitivity or specificity would impair the efficiency of the other. Conclusions: Serum tumor markers CA15-3, CA12-5, and CEA might have little clinical significance in predicting neoadjuvant treatment response in locally advanced breast cancer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4398-4404
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• 2015

Stainless steel sheets are widely used as the structural material for dynamic machine structures, These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding, For fatigue design of gas welded joints such as various type joint. It is necessary to obtain design information on stress distribution at the weldment as well as fatigue strength of gas welded joints. Thus in this paper, ${\Delta}P-N_f$ curves were obtained by fatigue tests. and, ${\Delta}P-N_f$ curves were rearranged in the ${\Delta}{\sigma}-N_f$ relation with the hot spot stresses at the gas welded joints. Using these results, the accelerated life test(ALT) is conducted. From the experiment results, an life prediction model is derived and factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

• Journal of Dental Anesthesia and Pain Medicine
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• v.15 no.3
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• pp.135-140
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• 2015

Background: Identifying early markers of septic complications can aid in the diagnosis and therapeutic management of hospitalized patients. In this study, the utility of procalcitonin (PCT) vs. C-reactive protein (CRP) as early markers of sepsis was compared. Methods: A series of 2,697 consecutive blood samples was collected from hospitalized patients and serum PCT and CRP levels were measured. Patients were categorized by PCT level as follows: < 0.05 ng/ml, 0.05-0.49 ng/ml, 0.5-1.99 ng/ml, 2-9.99 ng/ml, and > 10 ng/ml. Diagnostic utility was analyzed by receiver operating characteristic (ROC) curves. Results: Mean CRP levels varied among the five PCT categories at $0.31{\pm}2.87$, $5.65{\pm}6.26$, $13.78{\pm}8.01$, $12.15{\pm}10.16$, and $17.77{\pm}10.59$, respectively (P < 0.05). PCT and CRP differed between positive and negative blood culture groups (PCT: 15.9 vs. 4.78 mg/dl;CRP: 11.5 ng/ml vs. 9.57 ng/ml;P < 0.05). The areas under the ROC curves (PCT, 95% confidence interval [CI]: 0.743, range: 0.698-0.789 at a threshold of 0.5 ng/ml; CRP, 95% CI: 0.540, range: 0.478-0.602 at a threshold of 8 mg/l) differed for PCT and CRP (P < 0.05). Conclusions: Therefore, PCT is a reliable marker for sepsis diagnosis and is more relevant than CRP in patients with a positive blood culture. These findings can be useful for the treatment of critically ill sepsis patients.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.351-360
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• 2009

This study is a series of experimental investigations of the buckling strengths of eccentrically compressed, cold-formed, stainless-steel, circular, hollow-section beam columns. The principal parameters that were used in this study were the slenderness ratios (Lk/r = 30, 50, 70) and the magnitude of eccentricity e(one way: 0, 25, 50, 75, and 100mm: the other way: 0, 12.5, 25, 37.5, and 50mm) on the asymmetrical end-moment of a double curvature. The objectives of the study were to obtain the maximum loads through an experiment and to compare the experimental behaviors with the analysis results. The ultimate buckling strength of the square section members were evaluated using a numerical method, in accordance with the bending moment-axial force(M-P) interaction curves. The behavior of each specimen was displayed in the form of the strength-displacement and moment-angle(M-$\theta$) relationship.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.467-474
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• 2010

Stainless steel sheets are widely used as the structural material for railroad cars and commercial vehicles. Structures made of stainless steel sheets are commonly fabricated by gas welding, For the fatigue design of gas welded joints such as fillet joints, it is necessary to obtain design information of the stress distribution at the weldment as well as the fatigue strength of the gas-welded joints. Further, the influence of the geometrical parameters of gas-welded joints on stress distribution and fatigue strength must be evaluated. in this study, ${\Delta}P-N_f$ curves were obtained by fatigue tests. and, the ${\Delta}P-N_f$ curves were rearranged on the basis of the ${\Delta}{\sigma}-N_f$ relation for the hot-spot stresses at the gas-welded joints. These results, were used for conducting an accelerated life test(ALT) From the experiment results, an acceleration model was derived and factors were estimated. The objective is to obtain the information required for the analysis of the fatigue lifetime of fillet welded joints and for data analysis by the statistic reliability method to save time and cost and to develop optimum accelerated life prediction plans.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.847-853
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• 2005

A total of 60 growth curves were generated with combinations of temperature, pH, and potassium lactate (PL) (60% (v/v) commercial solution) to determine the lag time (LT) and specific growth rate (SGR) of L. monocytogenes in broth. LT and SGR were significantly (P<0.05) affected by temperature, pH, concentration of PL, or the combined interaction of these factors. LT was extended and SGR was reduced significantly (P<0.05) by increased concentration of PL at lower temperature and pH. Listericidal effect was observed in the broth containing 2, 3, and 4% PL at pH 5.0 and $4^{\circ}C$. The antimicrobial activity of PL against L. monocytogenes increased when the pH of the medium was decreased at all temperatures tested. The results suggest that PL has antimicrobial properties to suppress the growth of L. monocytogenes. Potassium lactate has many potential applications as an antimicrobial additive in variety of refrigerated ready-to-eat foods.

• Corrosion Science and Technology
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• v.5 no.3
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• pp.85-89
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• 2006

KAERI(Korea Atomic Energy Research Institute) has developed a repassivation rate test system which can be operated at $300^{\circ}C$. It consists of an autoclave, three electrodes for an electrochemical test and a diamond scratch tip. All the electrodes are electrically insulated from the autoclave by using high temperature fittings. Reproducible repassivation curves of alloy 600 at 300 C were obtained. Repassivation rate of alloy 600 at pH 13 was slower than that of pH 10. Stress corrosion cracking test was carried as a function of the pH at a high temperature. At pH 10, alloy 600 showed a severe stress corrosion cracking(SCC), whereas it did not show a SCC at pH 7. From the viewpoint of a relationship between the current density and the charge density, a big difference was observed in the two solutions; the slope of pH 13 was steeper than that of pH 10. So the stress corrosion susceptibility at pH 13 seems to be higher than that of pH 10. The system would be a good tool to evaluate the SCC susceptibility of alloy 600 at a high temperature.