• Korean Chemical Engineering Research
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• v.60 no.4
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• pp.550-556
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• 2022

The performance of enzymatic fuel cells that convert chemical energy contained in various organic molecules such as sugar, alcohol, organic acids, and amino acids into electrical energy is greatly affected by the cathode as well as the anode. This study aimed to develop a laccase-based cathode with high performance. An enzyme composite composed of an laccase, redox mediator, and carbon nanotubes was immobilized on the surface of electrode in multiple layers, and the effect of the number of layers and the presence or absence of carbon nanotubes on electrode performance was investigated. As the number of layers of the enzyme-mediator (Lac-(PVI-Os-dCl)) on the electrode surface increased, the amount of reduction current generated at the electrode increased. The enzyme-carbon nanotube-mediator composite electrode (Lac-SWCNTs-(PVI-Os-dCl)) generated a current 1.7 times greater than that of the Lac-(PVI-Os-dCl). It was found that the largest amount of current (10.1±0.1 µA) was generated in the electrode composed of two layers of Lac-(PVI-Os-dCl) and two layers of Lac-SWCNTs-(PVI-Os-dCl) in the evaluation of electrodes with different ratio of Lac-SWCNTs-(PVI-Os-dCl) and Lac-(PVI-Os-dCl). The maximum power density of the cell using the cathode composed of a single layer of Lac-(PVI-Os-dCl) and the cell using the optimized cathode were 0.46±0.05 and 1.23±0.04 µW/cm², respectively. In this study, it was demonstrated that the performance of cathode and the enzymatic fuel cell using the same can be improved by optimizing the layers of composites composed of laccase, redox mediator, and carbon nanotubes on the electrode surface.

• Journal of Chest Surgery
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• v.53 no.3
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• pp.93-103
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• 2020

Background: Risk assessment for pulmonary resection in patients with early-stage non-small-cell lung cancer (NSCLC) is important for minimizing postoperative morbidity. Depletion of skeletal muscle mass is closely associated with impaired nutritional status and limited physical ability. We evaluated the relationship between skeletal muscle depletion and early postoperative complications in patients with early-stage NSCLC. Methods: Patients who underwent curative lung resection between 2016 and 2018 and who were diagnosed with pathological stage I/II NSCLC were included, and their records were retrospectively analyzed. The psoas volume index (PVI, ㎤/㎥) was calculated based on computed tomography images from routine preoperative positron emission tomography-computed tomography. Early postoperative complications, defined as those occurring within 90 days of surgery, were compared between the lowest sex-specific quartile for PVI and the remaining quartiles. Results: A strong correlation was found between the volume and the cross-sectional area of the psoas muscle (R²=0.816). The overall rate of complications was 57.6% among patients with a low PVI and 32.8% among those with a normal-to-high PVI. The most common complication was prolonged air leak (low PVI, 16.9%; normal-to-high PVI, 9.6%), followed by pneumonia (low PVI, 13.6%; normal-to-high PVI, 7.9%) and recurrent pleural effusion (low PVI, 11.9%; normal-to-high PVI, 6.8%). The predictors of overall complications were low PVI (odds ratio [OR], 2.18; 95% confidence interval [CI], 1.07-4.09; p=0.03), low hemoglobin level (OR, 0.686; 95% CI, 0.54-0.87; p=0.002), and smoking history (OR, 3.93; 95% CI, 2.03-7.58; p<0.001). Conclusion: Low PVI was associated with a higher rate of early postoperative complications in patients with early-stage NSCLC.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.3
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• pp.155-160
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• 2013

Purpose: The purpose of this study is to establish the acceptable intraoral application time of antiseptic agents and evaluate the effect of mechanical irrigation. Methods: A total of 80 subjects were selected for this study. Saliva secreted at the resting state was taken. The subjects were divided into 8 experimental groups, and kept 10% povidone-iodine (PVI) or 0.2% chlorhexidine gluconate (CHX) for 20 or 40 seconds in their oral cavity with/without irrigation of the oral cavity with sterilized normal saline, respectively. Then, the saliva was taken and diluted with phosphate buffered saline and then plated onto 5% sheep blood agar plates, which were incubated. Colony forming unit (CFU) was measured for the salivary bacterial counts. Results: After application of PVI and CHX, all the experimental groups showed statistically significant decrease in CFU (P<0.01). Group 2 (PVI, 40 s) showed more significant reduction rate in CFU than group 4 (CHX, 40 s; P<0.01). Group 6 (PVI, 40 s, irrigated) showed more significant reduction rate than group 2 (PVI, 40 s; P<0.01). Group 2 (PVI, 40 s) showed more significant reduction rate than group 1 (PVI, 20 s; P<0.01). Conclusion: Application of PVI for 40 seconds and mechanical irrigation with sterilized normal saline showed the best result among the 8 groups in terms of the reduction rate of salivary bacterial counts.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.4
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• pp.393-402
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• 2007

Remote sensing data can be integrated into crop models, making simulation improved. A crop model that uses remote sensing data was evaluated for its capability, which was performed through comparing three different methods of canopy measurement for cotton(Gossypium hirsutum L.). The measurement methods used were leaf area index(LAI), hand-held remotely sensed perpendicular vegetation index(PVI), and satellite remotely sensed PVI. Simulated values of cotton growth and lint yield showed reasonable agreement with the corresponding measurements when canopy measurements of LAI and hand-held remotely sensed PVI were used for model calibration. Meanwhile, simulated lint yields involving the satellite remotely sensed PVI were in rough agreement with the measured lint yields. We believe this matter could be improved by using remote sensing data obtained from finer resolution sensors. The model not only has simple input requirements but also is easy to use. It promises to expand its applicability to other regions for crop production, and to be applicable to regional crop growth monitoring and yield mapping projects.

• Journal of the Korean Electrochemical Society
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• v.19 no.2
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• pp.29-38
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• 2016

Screen printed carbon electrodes (SPCEs) with immobilized osmium-based hydrogel redox polymer, uricase and PEGDGE can be used to apply uric acid electrochemical detecting. The osmium redox complexes were synthesized by the coordinating pyridine group having different functional group at 4-position with osmium compounds. The synthesized poly-osmium hydrogel complexes are described as PAA-PVI-$[Os(dCl-bpy)_2Cl]^{+/2+}$, PAA-PVI-$[Os(dme-bpy)_2Cl]^{+/2+}$, PAA-PVI-$[Os(dmo-bpy)_2Cl]^{+/2+}$. The different concentrations of uric acid were measured by cyclic voltammetry technique using enzyme-immobilized SPCEs. The prepared SPCEs using PAA-PVI-$[Os(dme-bpy)_2Cl]^{+/2+}$ showed no interference from common physiologic interferents such as ascorbic acid (AA) or glucose. The resulting electrical currents at 0.33 V vs. Ag/AgCl displayed a good linear response with uric acid concentrations from 1.0 to 5.0 mM. Therefore, this approach allowed the development of a simple, point of care in the medical field, disposable electrochemical uric acid biosensor.

• Journal of Aerospace System Engineering
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• v.6 no.2
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• pp.1-6
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• 2012

On this study, as a Human Factor(HF)'s point of view, typical PVI(Pilot Vehicle Interface) evaluation for small airplane cockpit design, PVI evaluation items and procedures to show compliance to KAS Part 23 "Airworthiness Standards : Normal, Utility, Acrobatic, And Commuter Category Airplanes" are introduced and reviewed. This study is based on the experience of Korean small civil airplane development and certification program.

• Journal of Korean Academy of Nursing
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• v.38 no.1
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• pp.39-44
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• 2008

Purpose: The purpose of this study was to compare 1% chlorhexidine-gluconate/61% ethanol (CHG/Ethanol) emollient and 7.5% povidone-iodine (PVI) scrub for antimicrobial, residual effect, and skin condition. Method: CHG/Ethanol emollient hand hygiene was performed waterless, and brushless by operating doctors and nurses (N=20). PVI hand washing was performed with water and a brush (N=20) for 5 min. The subjects were asked to press their left hand in hand-shaped agar before a surgical scrub, immediately after a surgical scrub and after the operation. The amount of isolated microorganisms were calculated by counting the number of divided areas($1{\times}1cm$, 160 cell) which were culture positive in the hand culture plate. The skin condition was evaluated. Result: The antimicrobial count of CHG/Ethanol emollient and PVI immediately post surgical scrub was 0.0 vs. 4.1 (p>.05), and after the operation was 0.1 vs. 37.8 (p>.05)respectively. The Residual effect of CHG/Ethanol emollient immediately post surgical scrub and after the operation were 0.0 vs. 0.1 (p>.05), and PVI were 4.1 vs. 37.8 (p>.05)respectively. The skin condition and satisfaction of CHG/Ethanol emollient was higher than PVI (p<.05). Conclusion: The antimicrobial effect between CHG/Ethanol emollient and PVI were the same. Considering skin condition, satisfaction and allergic reaction CHG/Ethanol emollient for surgical scrub is recommended in Korea.

• Membrane Journal
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• v.33 no.4
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• pp.211-221
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• 2023

This study presents a comprehensive study on the synthesis and characterization of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C flexible electrodes for energy storage applications. The dual-functional PVI-PGMA copolymer exhibited excellent ionic conductivity, with the PVI-PGMA73/LiTFSI200 membrane electrolyte achieving the highest conductivity of 1.0 × 10^-3 S cm^-1. The electrochemical performance of the CxNy-C electrodes was systematically investigated, with C3N2-C demonstrating superior performance, achieving the highest specific capacitance of 958 F g^-1 and lowest charge transfer resistance (R_ct) due to its highly interconnected hybrid structure comprising nanowires and polyhedrons, along with binary Co/Ni oxides, which provided abundant redox-active sites and facilitated ion diffusion. The presence of a graphitic carbon shell further contributed to the enhanced electrochemical stability during charge-discharge cycles. These results highlight the potential of PVI-PGMA/LiTFSI polymeric membrane electrolytes and CxNy-C electrodes for advanced energy storage devices, such as supercapacitors and lithium-ion batteries, paving the way for further advancements in sustainable and high-performance energy storage technologies.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.5
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• pp.312-315
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• 2009

Objective: It is important to sterilize oral cavity with antibacterial agent before surgery for preventing infection. The object of this study was to compare the effect on reduction of salivary bacterial counts according to applied time when povidone-iodine (PVI) and chlorhexidine gluconate (CHX), most broadly used materials in dentistry, were applied intraorally before the surgery. Methods: Sixty subjects were divided into 6 groups. PVI and CHX were applied in each group for 1, 2 and 3 minutes, respectively. Then salivary microbacteria taken before and after applying the materials were cultured using 5% sheep blood agar plate. Results: There was significant difference in reduction of microbacteria in both PVI and CHX and the effect did not show differences depending on time. When applied for a minute, PVI showed somewhat higher reduction rate than CHX, but in the other groups, there was no difference in reduction rate. Conclusion: We found that there was no significant difference in sterilization ability of PVI and CHX in all groups in this study. Therefore, both agents would get sufficient effect when applied for a minute.

• Phonetics and Speech Sciences
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• v.15 no.3
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• pp.27-35
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• 2023

This study aimed to investigate the effect of Chinese on the production of Korean rhythm. Korean and Chinese are typologically classified into different rhythmic categories; because of this, the phonological properties of Korean and Chinese are similar and different at the same time. As a result, Chinese can exert both positive and negative influences on the realization of Korean rhythm. To investigate the influence of the rhythm of the native language of L2 learners on their target language, we conducted an acoustic analysis using acoustic metrics like of the speech of 5 Korean native speakers and 10 advanced Chinese Korean learners. The analyzed material is a short paragraph of five sentences containing a variety of syllable structures. The results showed that KS and CS rhythms are similar in %V, VarcoV, and nPVI_S. However, CS, unlike KS, showed characteristics closer to those of a stress-timed language in the values of %V and VarcoV. There was also a significant difference in nPVI_V values. These results demonstrate a negative influence of the native language in the realization of Korean rhythm. This can be attributed to the fact that all vowels in Chinese sentence are not pronounced with the same emphasis due to neutral tone. In this sense, this study allowed us to observe influences of L1 on L2 production of rhythm.