• Journal of Rhinology
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• v.25 no.2
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• pp.75-79
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• 2018

Background and Objectives: To investigate the common site of recurrent epistaxis after initial intervention such as packing and cauterization had failed and to evaluate the efficacy of surgical endoscopic electrocautery. Subjects and Method: Retrospective review of 47 patients with recurrent and uncontrolled idiopathic epistaxis between October 1995 and March 2016. All patients underwent endoscopic examination in the operating room after hospitalization. We performed electrocautery when a bleeding site was found. Results: The most common sites of bleeding were the inferior meatus (28%), sphenoethmoid recess (23%), superior septum around the olfactory cleft (13%), and the posterior end of the middle turbinate (15%). There was no serious complication during the one week after surgery. In 46 (98%) patients, refractory epistaxis was successfully controlled. One patient had recurrent epistaxis after electrocautery and underwent endoscopic sphenopalatine artery ligation. Conclusion: In patients with refractory idiopathic epistaxis after failure of first-line treatment, endoscopic examination through a surgical approach and electrocautery for suspected bleeding are effective.

• Applied Chemistry for Engineering
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• v.31 no.6
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• pp.596-602
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• 2020

Blending process of adhesive production has a cooling process to cool down the temperature of the solution which was heated up to 76 ℃ with a mineral insulated (MI) cable by 30 ℃ at room temperature. Using a MI cable in the adhesive production process makes the production inefficient because it takes about 10 h for the cooling process. If a jacketed vessel is used instead of the MI cable, it would shorten the cooling downtime without any additional cooling system by using cold water. However, there are various types of jacketed vessels, and thus the most suitable type should be found before set up. In this study, we designed the optimized jacketed vessel for the adhesive production process by calculating the cooling downtime, which impacts production efficiency, as a function of the jacket types using computational fluid dynamics. As a result, the cooling performance of the plain jacket was 32.7% superior to that of the half-pipe coil jacket with the same height. In addition, the plain jacket with 60% spiral baffle reduced the cooling downtime and operating time by 80.4% and 25.1%, respectively.

• Korean small business review
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• v.42 no.4
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• pp.123-146
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• 2020

This study, targeting KOSDAQ-listed companies, examined the relationship between variability of accruals and corporate characteristics. First, the analysis results show that executives of companies with high debt ratios are more likely to violate debt contracts, so there is a strong temptation to use discretionary accrual items. Second, for companies with large volatility in operating cash flows, Executives of these companies are strongly inclined to utilize accruals for the purpose of abuse of discretion. Third, the larger the company, the more sensitive it is to political costs, so it is less tempted to use the accruals item than a smaller company. Fourth, the corporate age is thought to be the maturity of the company, Executives of such companies have little room to use accruals to abuse their discretion. Fifth, in the case of profit dummy variables, the companies reporting losses have more temporary accrual items than those reporting profits, so this increases the uncertainty in their accounting information than the latter. Sixth, for those companies that are indicated as inappropriate as a result of audit, the more likely their executives are to use the accrual items, and the lower the quality of their accounting profits is. Lastly, Companies audited by 4 Big domestic accounting firms have less discretionary accrual fluctuations than companies audited by non-big 4 accounting firms. Thus, it was found that the accrual amount allows the discretion of corporate executives differently according to the characteristics of the company.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.307-312
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• 2023

In this study, a catalytic oxidation-heat recovery system was designed that can remove unreacted with a concentration of about 1% to 6% in the exhaust gas of hydrogen fuel cells and recover heat to ensure safety in the hydrogen economy. The safety system was devised by filling hydrogen oxidation catalysts at room temperature that can remove unreacted hydrogen without any energy source, and an exhaust-heat recovery device was integrated to efficiently recover the heat released from the oxidation reaction. Through CFD analysis, variations in pressure and fluid within the system were shown depending on the filling conditions of the hydrogen oxidation system. In addition, it was found that waste heat could be recovered by optimizing the temperature of the exhaust gas, flow rate, and pressure conditions within the heat recovery system and securing hot water above 40 ℃ by utilizing the exhaust gas oxidation heat source above 300 ℃. Through this study, it was possible to confirm the potential of utilizing hydrogen processes, which are applied in small to medium-sized systems such as hydrogen fuel cells, as a safety system by evaluating them at a pilot scale. Additionally, it could be a safety guideline for responding to unexpected hydrogen safety accidents through further pilot-scale studies.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.1-10
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• 2023

Due to the development of the industrial revolution, regulations on exhaust emissions have been continuously strengthened to reduce the rapidly increasing greenhouse gas emissions. The use of environmentally friendly fuels is essential to meet these regulations. Hydrogen has been attracting attention as a future environmentally friendly fuel, but due to its material properties, it faces significant challenges in handling and storage. As an alternative, ammonia has been proposed. Ammonia can be easily liquefied at room temperature compared to hydrogen and has a high energy density. In order to examine the applicability of ammonia as an engine fuel, experiments were conducted to investigate the effects of changes in combustion control parameters in a direct injection ammonia combustion engine. The experiments were conducted by varying two variables: spark timing and excessive air ratio. Observations were made on combustion stability and the trends of exhaust emissions such as nitrogen oxides and unburned ammonia under the conditions of an engine speed of 1,500 rpm and medium to high loads (brake torque of 200 Nm). By optimizing the combustion control parameters, conditions for stable combustion even when using ammonia as the sole fuel were identified, and plans are underway to apply strategies for future expansion of the operating range.

• Journal of Trauma and Injury
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• v.37 no.1
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• pp.20-27
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• 2024

Purpose: Severe abdominal injuries often require immediate clinical assessment and surgical intervention to prevent life-threatening complications. In Jeju Regional Trauma Center, we have instituted a protocol for emergency department (ED) laparotomy at the trauma bay. We investigated the mortality and time taken from admission to ED laparotomy. Methods: We reviewed the data recorded in our center's trauma database between January 2020 and December 2022 and identified patients who underwent laparotomy because of abdominal trauma. Laparotomies that were performed at the trauma bay or the ED were classified as ED laparotomy, whereas those performed in the operating room (OR) were referred to as OR laparotomy. In cases that required expeditious hemostasis, ED laparotomy was performed appropriately. Results: From January 2020 to December 2022, 105 trauma patients admitted to our hospital underwent emergency laparotomy. Of these patients, six (5.7%) underwent ED laparotomy. ED laparotomy was associated with a mortality rate of 66.7% (four of six patients), which was significantly higher than that of OR laparotomy (17.1%, 18 of 99 patients, P=0.006). All the patients who received ED laparotomy also underwent damage control laparotomy. The time between admission to the first laparotomy was significantly shorter in the ED laparotomy group (28.5 minutes; interquartile range [IQR], 14-59 minutes) when compared with the OR laparotomy group (104 minutes; IQR, 88-151 minutes; P<0.001). The two patients who survived after ED laparotomy had massive mesenteric bleeding, which was successfully ligated. The other four patients, who had liver laceration, kidney rupture, spleen injury, and pancreas avulsion, succumbed to the injuries. Conclusions: Although ED laparotomy was associated with a higher mortality rate, the time between admission and ED laparotomy was markedly shorter than for OR laparotomy. Notably, major mesenteric hemorrhages were effectively controlled through ED laparotomy.

• Hip & pelvis
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• v.34 no.1
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• pp.25-34
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• 2022

Purpose: Mortality rates following hip fracture surgery have been well-studied. This study was conducted to examine mortality rates in asymptomatic patients presenting for treatment of acute hip fractures with concurrent positive COVID-19(+) tests compared to those with negative COVID-19(-) tests. Materials and Methods: A total of 149 consecutive patients undergoing hip fracture surgery during the COVID-19 pandemic at two academic medical centers were reviewed retrospectively. Patients were divided into two groups for comparative analysis: one group included asymptomatic patients with COVID-19+ tests versus COVID-19- tests. The primary outcome was mortality at 30-days and 90-days. Results: COVID-19+ patients had a higher mortality rate than COVID-19- patients at 30-days (26.7% vs 6.0%, P=0.005) and 90-days (41.7% vs 17.2%, P=0.046) and trended towards an increased length of hospital stay (10.1±6.2 vs 6.8±3.8 days, P=0.06). COVID-19+ patients had more pre-existing respiratory disease (46.7% vs 11.2%, P=0.0002). Results of a Cox regression analysis showed an increased risk of mortality at 30-days and 90-days from COVID-19+ status alone without an increased risk of death in patients with pre-existing chronic respiratory disease. Conclusion: Factors including time to surgery, age, preexisting comorbidities, and postoperative ambulatory status have been proven to affect mortality and complications in hip fracture patients; however, a positive COVID-19 test result adds another variable to this process. Implementation of protocols that will promote prompt orthogeriatric assessments, expedite patient transfer, limit operating room traffic, and optimize anesthesia time can preserve the standard of care in this unique patient population.

• Anatomy and Cell Biology
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• v.57 no.3
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• pp.333-345
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• 2024

Stem cells transplantation (SCT) is known as a newfound strategy for multiple sclerosis (MS) treatment. Human umbilical cord mesenchymal stem cells (hUCMSCs) contain various regenerative features. Experimental autoimmune encephalomyelitis (EAE) is a laboratory model of MS. This meta-analysis study was conducted to assess the overall therapeutic effects of hUCMSCs on reduction of clinical score (CS) and restoration of active movement in EAE-induced animals. For comprehensive searching (in various English and Persian databases until May 1, 2024), the main keywords of "Experimental Autoimmune Encephalomyelitis", "Multiple Sclerosis", "Human", "Umbilical Cord", "Mesenchymal", and "Stem Cell" were hired. Collected data were transferred to the citation manager software (EndNote x8) and duplicate papers were merged. Primary and secondary screenings were applied (according to the inclusion and exclusion criteria) and eligible studies were prepared for data collection. CS of two phases of peak and recovery of EAE were extracted as the difference in means and various analyses including heterogeneity, publication bias, funnel plot, and sensitivity index were reported. Meta-analysis was applied by CMA software (v.2), P<0.05 was considered a significant level, and the confidence interval (CI) was determined 95% (95% CI). Six eligible high-quality (approved by ARRIVE checklist) papers were gathered. The difference in means of peak and recovery phases were -0.775 (-1.325 to -0.225; P=0.006; I²=90.417%) and -1.230 (-1.759 to -0.700; P<0.001; I²=93.402%), respectively. The overall therapeutic effects of SCT of hUCMSCs on the EAE cases was -1.011 (95% CI=-1.392 to -0.629; P=0.001). hUCMSCs transplantation through the intravenous route to the animal MS model (EAE) seems a considerably effective procedure for the alleviation of motor defects in both phases of peak and recovery.

• Radiation Oncology Journal
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• v.33 no.4
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• pp.337-343
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• 2015

Purpose: The purpose of this report is to describe the proton therapy system at Samsung Medical Center (SMC-PTS) including the proton beam generator, irradiation system, patient positioning system, patient position verification system, respiratory gating system, and operating and safety control system, and review the current status of the SMC-PTS. Materials and Methods: The SMC-PTS has a cyclotron (230 MeV) and two treatment rooms: one treatment room is equipped with a multi-purpose nozzle and the other treatment room is equipped with a dedicated pencil beam scanning nozzle. The proton beam generator including the cyclotron and the energy selection system can lower the energy of protons down to 70 MeV from the maximum 230 MeV. Results: The multi-purpose nozzle can deliver both wobbling proton beam and active scanning proton beam, and a multi-leaf collimator has been installed in the downstream of the nozzle. The dedicated scanning nozzle can deliver active scanning proton beam with a helium gas filled pipe minimizing unnecessary interactions with the air in the beam path. The equipment was provided by Sumitomo Heavy Industries Ltd., RayStation from RaySearch Laboratories AB is the selected treatment planning system, and data management will be handled by the MOSAIQ system from Elekta AB. Conclusion: The SMC-PTS located in Seoul, Korea, is scheduled to begin treating cancer patients in 2015.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.128-132
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• 2010

Purpose: Nuclear medicine general operation room is radioactive control room which is used for the handling of radioisotope(R.I). Radioactive contamination materials must be under control and separated from general trash. With this experiments, we want to actively suggest the guideline of controling and operating radioactive contamination materials by measuring contamination degree and analyzing the causes which is not realized so far. Materials and Methods: Materials are selected from Oct. 2009 to March. 2010. salines which are used for labelling radiophamaceuticals and generator cap, saline needle cap, $^{99m}Tc$-needle cap saline vial which is generated from $^{99}Mo$/$^{99m}Tc$ generator. After measuring each surface contamination degree by survey meter, mean value and standard deviation one were solved out. Results: In result, After measuring surface contamination degree, radioactivity of saline for labelling radiophamaceuticals showed $14429{\pm}26378$ cpm (p<0.05) and in measured generators, foreign imported things showed that generator cap : $9{\pm}21$ cpm, saline vial : $17{\pm}28$ cpm. saline needle cap : $35{\pm}66$ cpm, $^{99m}Tc$-needle cap : $9{\pm}21$ cpm, saline vial $13{\pm}28$ cpm. domestic things showed that generator cap : $22852{\pm}52545$ cpm, saline needle cap : $87367{\pm}109711$ cpm, $^{99m}Tc$-needle cap : $9008{\pm}10459$ cpm, saline vial : $186416{\pm}158196$ cpm (p<0.05). Conclusion: The saline which is used for labelling, exceeded 1/10 of maximum permissible range. this is generated from radiophamaceuticals dilution procedure. and In generators, radioactive value of foreign import things showed closely background value. but which of domestic thing showed that exceeded more than 1000 values 1/10 of maximum permissible range. the causes of that is domestic generator is contaminated in manufacturing procedure. So, to dispose radioactive contamination materials which is could betaken out of, the control and operation must be radical under controlled by radioactive measuring, recording and equipping of its own. if this is kept well, we can prevent surely that radioactive waste could be disposed like as general trash.