• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.2
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• pp.89-96
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• 2022

Background and Objectives The quality of life after thyroidectomy, such as voice change, is considered to be as important as control of the disease. In this study, we aimed to evaluate changes in both subjective and objective voice parameters after thyroidectomy resulting in normal morbidity of the vocal cords. Materials and Method In this prospective cohort study, 204 patients who underwent thyroidectomy with or without central neck dissection at a single referral center from Feb 2015 to Aug 2016 were enrolled. All patients underwent prospective voice evaluations including both subjective and objective assessments preoperatively and then at 2 weeks, 3, 6, and 12 months postoperatively. Temporal changes of the voice parameters were analyzed. Results Values of the subjective assessment tool worsened during the early postoperative follow-up period and did not recover to the preoperative values at 12 months postoperatively. The maximal phonation time gradually decreased, whereas most objective parameters, including maximal vocal pitch (MVP), reached preoperative values at 3-6 months postoperatively. The initial decrease in MVP was significantly greater in patients undergoing total thyroidectomy, and their MVP recovery time was faster than that of patients undergoing lobectomy (p=0.001). Patients whose external branch of the superior laryngeal nerve was confirmed intact by electroidentification showed no difference in recovery speed compared with patients without electroindentification (p=0.102), although the initial decrease in MVP was lower with electroidentification. Conclusion Subjective assessment in voice quality and maximal phonation time after thyroidectomy did not show recovery to preoperative values. Aggravation of MVP was associated with surgical extent and electroidentification.

• Journal of Preventive Medicine and Public Health
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• v.5 no.1
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• pp.17-23
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• 1972

Carbon Monoxide poisoning is one of the most serious Public health problems in Korea. The incidence rate. officially reported has been known to be the highest in the world. This high incidence is mainly due to the wide prevalence of anthracite coal briquette as the domestic fuel for unique Korean heating system called 'ondol,' The coal briquette gas contains around 3-5% of Carbon Monoxide. A nation-wide effort to eliminate or reduce this serious hazards has produced little effect and the most hospitals are offering very ineffective measures such as oxygen inhalation through nasal catheter. Author has believed that this preventable accident should be approached by the secondary preventive measure because of our socio-economic status do not allow us optimistic results from primary preventive measure as far as the problem of CO poisoning is concerned. Author has treated 466 patients during 30 months period by Hyperbaric Oxygenation at Seoul National University Hospital. The results found are as follows. 1. Female has a higher incidence rate than male and the age group between 15-29 years showed highest incidence. 2. The recovery time depends on the time when the patients arrived at hospital. Earlier the arrival time, shorter the recovery time. 3. Some objective signs are representing typical physiological response to tissue hypoxia. 4. Therapeutic effectiveness of Hyperbaric Oxypenation is confirmed by such indices as recovery rate, Admission rate and average stay in hospital. Futher, these results are cocordant with other reports on the clinical value of Hyperbaric Oxygenation in the treatment of CO poisoning.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.12
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• pp.1092-1101
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• 2002

The objective of this study is to develop energy saving strategies for indoor swimming pools and to estimate the effect of each energy saving strategy. For this purpose, field measurements regarding pool water heating energy, domestic hot water heating energy are conducted and a base energy consumption model is implemented using the DOE-2.1E program. The results of the study reveal that 25% of the total pool water heating energy may be saved by using night time pool covers, 27% of the total domestic hot water heating energy may be saved by using a waste water heat recovery system (effic. 60%), and of the total ventilation energy may be saved using an exhaust air heat recovery system (effic. 60%).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.175-182
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• 2007

The objective of the present study is to investigate the heat storage characteristics of a packed bed according to periodically oscillating flows. Experiments have been performed to measure transient temperature distributions in solid and fluid Phases of the porous media. A simplified analytical model has been developed with intra-particle and dispersion effects neglected, and non-dimensional parameters have been derived. The transient temperature distributions according to the simplified numerical model agree well with the experimental results. Heat storage efficiencies defined in two different ways are obtained for various time periods and face velocities.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.457-464
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• 2010

Representative methods for removing spilled oil include mechanical skimming, chemical treatment, burning at the surface of the spilled oil, and microbiological degradation. Among these methods, mechanical skimmer is the most efficient. Mechanical skimming can be classified into the following categories: belt-type, disk-type, weir-type, drum-type. We designed models with a submerged orifice for use in our experiments, for an objective and systematic evaluation of the recovery efficiency of mechanical skimming. Basically, oil is lighter than seawater and hence tends to float on the surface of the latter if there is sufficient time for floating. The present skimmer is kind of wear-type with the submerged orifice for seawater to be squeezed through, minimizing water content in the tank. From the experimental results, we identify the parameters that influence the oil recovery rate and recovery efficiency. The recovery efficiency can be enhanced by increasing the thickness of the oil layer in the first oil accumulative tank.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.345-351
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• 2014

Purpose: Rapid detection of bacteria is very important in agricultural and food industries to prevent many foodborne illnesses. The objective of this study was to develop a portable nuclear magnetic resonance (NMR)-based system to detect foodborne pathogens (E. coli). This study was focused on developing a method to detect low concentrations of magnetic nanoparticles using NMR techniques. Methods: NMR relaxometry was performed to examine the NMR properties of iron nanoparticle mixtures with different concentrations by using a 1 T permanent magnet magnetic resonance imaging system. Exponential curve fitting (ECF) and inverse Laplace transform (ILT) methods were used to estimate the NMR relaxation time constants, $T_1$ and $T_2$, of guar gum solutions with different iron nanoparticle concentrations (0, $10^{-3}$, $10^{-4}$, $10^{-5}$, $10^{-6}$, and $10^{-7}M$). Results: The ECF and ILT methods did not show much difference in these values. Analysis of the NMR relaxation data showed that the ILT method is comparable to the classical ECF method and is more sensitive to the presence of iron nanoparticles. This study also showed that the spin-spin relaxation time constants acquired by a Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence are more useful for determining the concentration of iron nanoparticle solutions comparwith the spin-lattice relaxation time constants acquired by an inversion recovery pulse sequence. Conclusions: We conclude that NMR relaxometry that utilizes CPMG pulse sequence and ILT analysis is more suitable for detecting foodborne pathogens bound to magnetic nanoparticles in agricultural and food products than using inversion recovery pulse sequence and ECF analysis.

• Korean Journal of Applied Biomechanics
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• v.33 no.3
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• pp.101-109
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• 2023

Objective: The aim of this study is to verify the differences in muscle characteristics of elite level swimmers before and after a 2-hour practice session. Method: The study was conducted on 15 elite swimmers. Preliminary measurements for each muscle (Anterior Deltoid, Triceps Brachii, Biceps Brachii, Flexor Carpi Ulnaris) were taken using the MyotonPRO device before training. After approximately 2 hours of training, the same muscle areas were measured again. The collected data was analyzed through descriptive statistics and two-way 2×2 RG·RM ANOVA, and all statistical significance levels were set at α=.05. Results: After analyzing the characteristics of the Flexor Carpi Ulnaris (FCU) before and after training in both proficiency level swimmers (excellent, non-excellent), it was found that the interaction effect of group X repetition in muscle tension (F), muscle stiffness (S), and body recovery time (R) was statistically significant. Secondly, in the analysis of the Biceps Brachii (BB), the main effect of repetition in muscle tension (F), muscle stiffness (S), and body recovery time (R) was statistically significant. Furthermore, the interaction effect of group X repetition in muscle stiffness (S) and body recovery time (R) was statistically significant. Conclusion: The efficient use of FCU and BB suggests that it is an important factor distinguishing the performance of excellent and non-excellent swimmers in swimming. Therefore, if we develop and apply measures to efficiently utilize FCU and BB during training, it can help improve the performance of the athletes.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.736-745
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• 2020

Objective: To identify the initial chest computed tomography (CT) findings and clinical characteristics associated with the course of coronavirus disease 2019 (COVID-19) pneumonia. Materials and Methods: Baseline CT scans and clinical and laboratory data of 72 patients admitted with COVID-19 pneumonia (39 men, 46.2 ± 15.9 years) were retrospectively analyzed. Baseline CT findings including lobar distribution, presence of ground glass opacities, consolidation, linear opacities, and lung severity score were evaluated. The outcome event was recovery with hospital discharge. The time from symptom onset to discharge or the end of follow-up (for those remained hospitalized) was recorded. Data were censored in events such as death or discharge without recovery. Multivariable Cox proportional hazard regression was used to explore the association between initial CT, clinical or laboratory findings, and discharge with recovery, whereby hazard ratio (HR) values < 1 indicated a lower rate of discharge at four weeks and longer time until discharge. Results: Thirty-two patients recovered and were discharged during the study period with a median length of admission of 16 days (range, 9 to 25 days), while the rest remained hospitalized at the end of this study (median, 17.5 days; range, 4 to 27 days). None died during the study period. After controlling for age, onset time, lesion characteristics, number of lung lobes affected, and bilateral involvement, the lung severity score on baseline CT (> 4 vs. ≤ 4 [reference]: adjusted HR = 0.41 [95% confidence interval, CI = 0.18-0.92], p = 0.031) and initial lymphocyte count (reduced vs. normal or elevated [reference]: adjusted HR = 0.14 [95% CI = 0.03-0.60], p = 0.008) were two significant independent factors that influenced recovery and discharge. Conclusion: Lung severity score > 4 and reduced lymphocyte count at initial evaluation were independently associated with a significantly lower rate of recovery and discharge and extended hospitalization in patients admitted for COVID-19 pneumonia.

• Biomedical Science Letters
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• v.23 no.2
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• pp.111-117
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• 2017

Leukocytes in blood components are involved in diverse adverse transfusion reactions such as febrile non-hemolytic transfusion reactions. Therefore, leukocyte reduction is required to reduce these adverse reactions. The objective of this study was to compare the efficiency of pre-storage filtration and post-storage filtration. Filtration time, residual leukocyte count, RBC recovery, and hemolysis were assessed after pre-storage or post-storage filtration. Compared to pre-storage filtration, filtration time was prolonged and hemolysis was dramatically increased when post-storage filtration was performed. Residual leukocytes count and RBC recovery after post-storage filtration were similar with those obtained after pre-storage filtration. These results suggest that pre-storage filtration has better efficiency than post-storage filtration. These are thought to contribute to the production of better quality of leukoreduction blood components.

• Archives of Plastic Surgery
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• v.42 no.6
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• pp.761-768
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• 2015

Background Surgical scars on the palmar surface of the hand may lead to functional and also aesthetic and psychological consequences. The objective of this study was to introduce a new incision technique for periarterial sympathectomy of the hand and to compare the results of the new two-step incision technique with those of a Koman incision by using an objective questionnaire. Methods A total of 40 patients (17 men and 23 women) with intractable Raynaud's disease or syndrome underwent surgery in our hospital, conducted by a single surgeon, between January 2008 and January 2013. Patients who had undergone extended sympathectomy or vessel graft were excluded. Clinical evaluation of postoperative scars was performed in both groups one year after surgery using the patient and observer scar assessment scale (POSAS) and the Wake Forest University rating scale. Results The total patient score was 8.59 (range, 6-15) in the two-step incision group and 9.62 (range, 7-18) in the Koman incision group. A significant difference was found between the groups in the total PS score (P-value=0.034) but not in the total observer score. Our analysis found no significant difference in preoperative and postoperative Wake Forest University rating scale scores between the two-step and Koman incision groups. The time required for recovery prior to returning to work after surgery was shorter in the two-step incision group, with a mean of 29.48 days in the two-step incision group and 34.15 days in the Koman incision group (P=0.03). Conclusions Compared to the Koman incision, the new two-step incision technique provides better aesthetic results, similar symptom improvement, and a reduction in the recovery time required before returning to work. Furthermore, this incision allows the surgeon to access a wide surgical field and a sufficient exposure of anatomical structures.