• Journal of the Korea Concrete Institute
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• v.21 no.1
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• pp.55-64
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• 2009

This study is aimed to derive the optimum mix proportion of the combined self compacting concrete according to cement types (blast-furnace slag cement and belite cement) and to propose the basic data to field construction work after evaluating the quality properties. Specially, lime stone powder (LSP) as binder and viscosity agent are used in the combined self compacting concrete because slurry wall of an underground LNG storage tank should be kept stability of quality during concrete working. Replacement ratio of LSP is determined by confined water ratio test and main design factors including fine aggregate ratio ($S_r$), coarse aggregate ratio ($G_v$) and water-cement ratio (W/C) are selected. Also, quality properties including setting time, bleeding content, shortening depth and hydration heat on the optimum mix proportion of the combined self compacting concrete according to cement type are compared and analyzed. As test results, the optimum mix proportion of the combined self compacting concrete according to cement type is as followings. 1) Slag cement type-replacement ratio of LSP 13.5%, $S_r$ 47% and W/C 41%. 2) Belite cement type-replacement ratio of LSP 42.7%, Sr 43% and W/C 51%. But optimum coarse aggregate ratio is 53% regardless of cement types. Also, as test results regarding setting time, bleeding content, shortening depth and hydration heat of the combined self compacting concrete by cement type, belite cement type is most stable in the quality properties and is to apply the actual construction work.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.361-364
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• 2002

This paper discusses the influencing factors such as coring position, height to diameter ratio of core specimen(h/d) and coring torque on the strength estimation of concrete by small site coring method in order to verify the validities of small size core method. According to results, as for the influence of drilling position, when core specimens are obtained from the place parallel to placing direction, compressive strength of core specimens are higher than those perpendicular to placing direction. This is due to the loss of the area of core specimen perpendicular to plating direction by bleeding. And in case of $\phi$ 24mm core specimen, when vertical drilling against placing direction is taken. compressive strength of core specimen obtained at the bottom of the structure is higher than that at the top of the structure. As for the influence of height to depth ratio, as h/d ratio increases compressive strength shows to be decreased. As for the influences of rotation speed of drilling machine, as its speed goes up, compressive strength decreases, regardless of core diameter.

• Journal of Chest Surgery
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• v.31 no.1
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• pp.32-39
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• 1998

High-dose aprotinin(Hammersmith regimen) has been widely used for years to control postoperative bleeding and reduce blood consumption in cardiac surgery but had known to cause some side-effects and had disadvantage in cost-effectiveness. The prospective controlled study of 33 patients undergoing cardiopulmonary bypass was performed to evaluate the efficacy for reducing postoperative bleeding and unfavorable effects of low-dose aprotinin. The level of hemoglobin and platelet in the blood and the amount of postoperative bleeding were assessed preoperatively, and postoperatively for the study of hemostatic function. The level of BUN and serum creatinine in the blood, levels of urine creatinine, total protein, albumin, alpha-1-microglobulin and creatinine clearance were assessed before and after the operation for the study of renal function. The aprotinin group had a significant reduction in chest tube drainage; 243$\pm$ 123 ml versus 406$\pm$303 ml(P=0.037) during 6 hours immediate-postoperatively, 494$\pm$358 ml versus 869$\pm$570 ml(P=0.045) during 24 hours postoperatively. The ratio of alpha-1-microglobulin/creatinine and microalbumin/creatinine in the urine were slightly increased in the aprotinin group postoperatively in comparison with the control group but there were no statistically significant difference(55$\pm$23 versus 24$\pm$10 in the alpha-1-microglobulin/creatinine, 56$\pm$19 versus 38$\pm$25 in the microalbumin/creatinine at post- operative 3rd day). There were no significant difference between two groups in other parameters of renal function, too. This study showed that low-dose aprotinin is an effective means of reducing postoperative bleeding without inducing significant renal dysfunction.

• Journal of Biomedical Engineering Research
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• v.42 no.4
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• pp.150-158
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• 2021

Intracranial hemorrhage (ICH) refers to acute bleeding inside the intracranial vault. Not only does this devastating disease record a very high mortality rate, but it can also cause serious chronic impairment of sensory, motor, and cognitive functions. Therefore, a prompt and professional diagnosis of the disease is highly critical. Noninvasive brain imaging data are essential for clinicians to efficiently diagnose the locus of brain lesion, volume of bleeding, and subsequent cortical damage, and to take clinical interventions. In particular, computed tomography (CT) images are used most often for the diagnosis of ICH. In order to diagnose ICH through CT images, not only medical specialists with a sufficient number of diagnosis experiences are required, but even when this condition is met, there are many cases where bleeding cannot be successfully detected due to factors such as low signal ratio and artifacts of the image itself. In addition, discrepancies between interpretations or even misinterpretations might exist causing critical clinical consequences. To resolve these clinical problems, we developed a diagnostic model predicting intracranial bleeding and its subtypes (intraparenchymal, intraventricular, subarachnoid, subdural, and epidural) by applying deep learning algorithms to CT images. We also constructed a visualization tool highlighting important regions in a CT image for predicting ICH. Specifically, 1) 27,758 CT brain images from RSNA were pre-processed to minimize the computational load. 2) Three different CNN-based models (ResNet, EfficientNet-B2, and EfficientNet-B7) were trained based on a training image data set. 3) Diagnosis performance of each of the three models was evaluated based on an independent test image data set: As a result of the model comparison, EfficientNet-B7's performance (classification accuracy = 91%) was a way greater than the other models. 4) Finally, based on the result of EfficientNet-B7, we visualized the lesions of internal bleeding using the Grad-CAM. Our research suggests that artificial intelligence-based diagnostic systems can help diagnose and treat brain diseases resolving various problems in clinical situations.

• Korean Circulation Journal
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• v.52 no.4
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• pp.304-319
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• 2022

Background and Objectives: De-escalation of dual-antiplatelet therapy through dose reduction of prasugrel improved net adverse clinical events (NACEs) after acute coronary syndrome (ACS), mainly through the reduction of bleeding without an increase in ischemic outcomes. Whether the benefits of de-escalation are sustained in highly thrombotic conditions such as ST-elevation myocardial infarction (STEMI) is unknown. We aimed to assess the efficacy and safety of de-escalation therapy in patients with STEMI or non-ST-segment elevation ACS (NSTE-ACS). Methods: This is a pre-specified subgroup analysis of the HOST-REDUCE-POLYTECH-ACS trial. ACS patients were randomized to prasugrel de-escalation (5 mg daily) or conventional dose (10 mg daily) at 1-month post-percutaneous coronary intervention. The primary endpoint was a NACE, defined as a composite of all-cause death, non-fatal myocardial infarction, stent thrombosis, clinically driven revascularization, stroke, and bleeding events of grade ≥2 Bleeding Academic Research Consortium (BARC) criteria at 1 year. Results: Among 2,338 patients included in the randomization, 326 patients were diagnosed with STEMI. In patients with NSTE-ACS, the risk of the primary endpoint was significantly reduced with de-escalation (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.48-0.89; p=0.006 for de-escalation vs. conventional), mainly driven by a reduced bleeding. However, in those with STEMI, there was no difference in the occurrence of the primary outcome (HR, 1.04; 95% CI, 0.48-2.26; p=0.915; p for interaction=0.271). Conclusions: Prasugrel dose de-escalation reduced the rate of NACE and bleeding, without increasing the rate of ischemic events in NSTE-ACS patients but not in STEMI patients.

• Computers and Concrete
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• v.30 no.6
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• pp.393-407
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• 2022

Due to the enormous cement content, pozzolanic materials, and the use of different aggregates, sustainable controlled low-strength material (CLSM) has a higher material cost than conventional concrete and sustainable construction issues. However, by selecting appropriate materials and formulations, as well as cement and aggregate content, whitethorn costs can be reduced while having a positive environmental impact. This research explores the desire to optimize plastic properties and 28-day unconfined compressive strength (UCS) of CLSM containing powder content from unprocessed-fly ash (u-FA) and recycled fine aggregate (RFA). The mixtures' input parameters consist of water-to-cementitious material ratio (W/CM), fly ash-to-cementitious materials (FA/CM), and paste volume percentage (PV%), while flowability, bleeding, segregation index, and 28-day UCS were the desired responses. The central composite design (CCD) notion was used to produce twenty CLSM mixes and was experimentally validated using MATLAB by an Artificial Neural Network (ANN). Variance analysis (ANOVA) was used for the determination of statistical models. Results revealed that the plastic properties of CLSM improve with the FA/CM rise when the strength declines for 28 days-with an increase in FA/CM, the diameter of the flowability and bleeding decreased. Meanwhile, the u-FA's rise strengthens the CLSM's segregation resistance and raises its strength over 28 days. Using calcareous powder as a substitute for cement has a detrimental effect on bleeding, and 28-day UCS increases segregation resistance. The response surface method (RSM) can establish high correlations between responses and the constituent materials of sustainable CLSM, and the optimal values of variables can be measured to achieve the desired response properties.

• Journal of Chest Surgery
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• v.57 no.1
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• pp.25-35
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• 2024

Background: Prothrombin complex concentrate (PCC) and fresh frozen plasma (FFP) are commonly used to manage bleeding in patients during cardiac surgery. However, the relative efficacy and safety of these 2 strategies remain uncertain. Methods: MEDLINE, Embase, and Cochrane were searched for studies comparing PCC and FFP in patients who underwent cardiac surgery complicated by bleeding. Review Manager (RevMan) ver. 5.4 (Nordic Cochrane Centre, The Cochrane Collaboration) was used for statistical analysis. Binary and continuous outcomes were compared using pooled risk ratios and mean differences, respectively. The meta-analysis protocol was registered in the International Prospective Register of Systematic Reviews under protocol number CRD42022379144. Results: We included 8 studies with 1,500 patients, of whom 613 (40.9%) received PCC. The mean follow-up period ranged from 28 to 90 days. The PCC group had significantly lower chest tube drainage at 24 hours (mean difference [MD], -148.50 mL; 95% CI, -253.02 to -43.99 mL; p=0.005; I² =42%). Fewer units of red blood cells (RBCs) were transfused within the first 24 hours (MD, -1.02 units; 95% CI, -1.81 to -0.24 units; p=0.01; I² =56%), and fewer patients required RBC transfusion within the first 24 hours (risk ratio, 0.85; 95% CI, 0.78-0.93; p<0.007; I² =45%) in the PCC group. There were no statistically significant differences in secondary outcomes. Nonetheless, a subgroup analysis of randomized controlled trials failed to corroborate the results obtained from the main analysis. Conclusion: Our findings suggest that PCC can be effective, without increased adverse events, when compared with FFP in patients undergoing cardiac surgery complicated by bleeding.

• Journal of Chest Surgery
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• v.57 no.2
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• pp.195-204
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• 2024

Background: Extracorporeal membrane oxygenation (ECMO) is an intervention for severe heart and lung failure; however, it poses the risk of complications, including gastrointestinal bleeding (GIB). Comprehensive analyses of GIB in patients undergoing ECMO are limited, and its impact on clinical outcomes remains unclear. Methods: This retrospective study included 484 patients who received venovenous and venoarterial ECMO between January 2015 and December 2022. Data collected included patient characteristics, laboratory results, GIB details, and interventions. Statistical analyses were performed to identify risk factors and assess the outcomes. Results: GIB occurred in 44 of 484 patients (9.1%) who received ECMO. Multivariable analysis revealed that older age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.01-1.06; p=0.0130) and need to change the ECMO mode (OR, 3.74; 95% CI, 1.75-7.96; p=0.0006) were significant risk factors for GIB, whereas no association was found with antiplatelet or systemic anticoagulation therapies during ECMO management. Half of the patients with GIB (22/44, 50%) underwent intervention, with endoscopy as the primary modality (19/22, 86.4%). Patients who underwent ECMO and developed GIB had higher rates of mortality (40/44 [90.9%] vs. 262/440 [59.5%]) and ECMO weaning failure (38/44 [86.4%] vs. 208/440 [47.3%]). Conclusion: GIB in patients undergoing ECMO is associated with adverse outcomes, including increased risks of mortality and weaning failure. Even in seemingly uncomplicated cases, it is crucial to avoid underestimating the significance of GIB.

• Clinical Endoscopy
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• v.56 no.5
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• pp.578-589
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• 2023

Background/Aims: The safety of endoscopic retrograde cholangiopancreatography (ERCP) in hepatic cirrhosis and the impact of Child-Pugh class on post-ERCP complications need to be better studied. We investigated the post-ERCP complication rates in patients with cirrhosis compared with those without cirrhosis. Methods: We conducted a literature search of relevant databases to identify studies that reported post-ERCP complications in patients with hepatic cirrhosis. Results: Twenty-four studies comprising 28,201 patients were included. The pooled incidence of post-ERCP complications in cirrhosis was 15.5% (95% confidence interval [CI], 11.8%-19.2%; I²=96.2%), with an individual pooled incidence of pancreatitis 5.1% (95% CI, 3.1%-7.2%; I²=91.5%), bleeding 3.6% (95% CI, 2.8%-4.5%; I²=67.5%), cholangitis 2.9% (95% CI, 1.9%-3.8%; I²=83.4%), and perforation 0.3% (95% CI, 0.1%-0.5%; I²=3.7%). Patients with cirrhosis had a greater risk of post-ERCP complications (risk ratio [RR], 1.41; 95% CI, 1.16-1.71; I²=56.3%). The risk of individual odds of adverse events between cirrhosis and non-cirrhosis was as follows: pancreatitis (RR, 1.25; 95% CI, 1.06-1.48; I²=24.8%), bleeding (RR, 1.94; 95% CI, 1.59-2.37; I²=0%), cholangitis (RR, 1.15; 95% CI, 0.77-1.70; I²=12%), and perforation (RR, 1.20; 95% CI, 0.59-2.43; I²=0%). Conclusions: Cirrhosis is associated with an increased risk of post-ERCP pancreatitis, bleeding, and cholangitis.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.4
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• pp.300-306
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• 2008

In the present study, the second order response surface method (RSM) is carried out to get optimum thermal design for enhancing heat transfer in a square channel with bleed flow. The RSM is used as an optimization technique. To calculate the heat transfer, RNG k-epsilon model and enhanced wall function are used. To design optimum rib turbulators, two design variables such as attack angle of rib $({\alpha})$ and rib pitch-to-rib height ratio (p/e) are optimized. In these analyses, the channel inlet Reynolds number was fixed at 10,000 in both non-bleeding and bleeding cases. The response surfaces of two design variables are constructed in cases with and without bleed flow. As a result, the optimum (or highest) heat transfer values are almost the same in ranges of two cases with and without bleed flow. However, the friction losses in the case with bleed flow are lower than those without bleed flow.