Publications by authors named "Kwanghyun Kim"

20 Publications

  • Page 1 of 1

Associations Between General Perceptions of COVID-19 and Posttraumatic Stress Disorder in Korean Hospital Workers: Effect Modification by Previous Middle East Respiratory Syndrome Coronavirus Experience and Occupational Type.

J Prev Med Public Health 2021 Mar 19;54(2):86-95. Epub 2021 Jan 19.

Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.

Objectives: This study investigated associations between perceptions of coronavirus disease 2019 (COVID-19) and the prevalence of posttraumatic stress disorder (PTSD) in workers at hospitals designated to treat COVID-19, as well as the difference in the magnitude of these associations by occupational type and previous Middle East respiratory syndrome coronavirus (MERS-CoV) experience.

Methods: The participants were workers at hospitals designated to treat COVID-19 who completed a questionnaire about their perceptions related to COVID-19, work experience during the previous MERS-CoV outbreak, and symptoms of PTSD ascertained by the PTSD Checklist for the Diagnostic and Statistical Manual of Mental Disorders. Participants' characteristics were compared using the chi-square test. Multivariable logistic regression was performed to evaluate the associations between perceptions and the prevalence of PTSD, stratified by occupational type and previous MERS-CoV experience.

Results: Non-medical personnel showed stronger associations with PTSD than medical personnel according to general fear (odds ratio [OR], 6.67; 95% confidence interval [CI], 1.92 to 23.20), shortages of supplies (OR, 1.29; 95% CI, 1.07 to 1.56), and issue-specific fear (OR, 1.29; 95% CI, 1.05 to 1.59). Those with prior MERS-CoV quarantine experience were more prone to PTSD than those without such experience in terms of general fear (OR, 1.70; 95% CI, 1.22 to 2.37), shortages of supplies (OR, 1.24; 95% CI, 1.10 to 1.40), and issue-specific fear (OR, 1.21; 95% CI, 1.06 to 1.38).

Conclusions: During the COVID-19 pandemic, non-medical personnel tended to have higher odds of being categorized as having PTSD. Workers with prior MERS-CoV experience were more susceptible than those without such experience. These findings suggest the need for timely interventions to manage human resources for a sustainable quarantine system.
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http://dx.doi.org/10.3961/jpmph.20.540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8046607PMC
March 2021

Neurocognitive Effects of Chemotherapy for Colorectal Cancer: A Systematic Review and a Meta-Analysis of 11 Studies.

Cancer Res Treat 2021 Mar 17. Epub 2021 Mar 17.

Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.

Purpose: Chemotherapy-related cognitive impairment (CRCI) is a controversial concept not much explored on colorectal cancer patients.

Materials And Methods: We identified eleven prospective studies: eight studies on 696 colorectal cancer patients who received chemotherapy and three studies on 346 rectal cancer patients who received neoadjuvant chemoradiotherapy. Standardized mean differences (SMDs) of neuropsychological test results and the cognitive quality-of-life scale were calculated using random effect models. A meta-regression was conducted to investigate the association between mean study population age and effect sizes.

Results: The association between chemotherapy and cognitive impairment was not clear in colorectal cancer patients (SMD, 0.003; 95% confidence interval, ‒0.080 to 0.086). However, a meta-regression showed that older patients are more vulnerable to CRCI than younger patients (β=‒0.016, p < 0.001).

Conclusion: Chemotherapy has an overall positive negligible effect size on the cognitive function of colorectal patients. Age is a significant moderator of CRCI.
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http://dx.doi.org/10.4143/crt.2020.1191DOI Listing
March 2021

Associations between social network properties and metabolic syndrome and the mediating effect of physical activity: findings from the Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) Cohort.

BMJ Open Diabetes Res Care 2020 07;8(1)

Department of Preventive Medicine, Yonsei University College of Medicine, Seodaemun-gu, Republic of Korea.

Introduction: Social isolation and loneliness are positively associated with metabolic syndrome. However, the mechanisms by which social isolation affects metabolic syndrome are not well understood.

Research Design And Methods: This study was designed as a cross-sectional study of baseline results from the Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) Cohort. We included 10 103 participants (8097 community-based low-risk participants, 2006 hospital-based high-risk participants) from the CMERC Cohort. Participants aged 65 years or older were excluded. Multiple imputation by chained equations was applied to impute missing variables. The quantitative properties of social networks were assessed by measuring the 'size of social networks'; qualitative properties were assessed by measuring the 'social network closeness'. Metabolic syndrome was defined based on the National Cholesterol Education Program Adult Treatment Panel III criteria. Multivariate logistic regression analyses were conducted to assess association between social network properties and metabolic syndrome. The mediating effects of physical inactiveness, alcohol consumption, cigarette smoking and depressive symptoms were estimated. Age-specific effect sizes were estimated for each subgroup.

Results: A smaller social network was positively associated with higher prevalences of metabolic syndrome in all subgroups, except the high-risk male subgroup. There was no clear association between social network closeness and metabolic syndrome. In community-based participants, an indirect effect through physical activity was detected in both sexes; however, in hospital-based participants, no indirect effects were detected. Cigarette smoking, alcohol consumption and depression did not mediate the association. Age-specific estimates showed that the indirect effect through physical activity had a greater impact in older participants.

Conclusions: A smaller social network is positively associated with metabolic syndrome. This trend could be partially explained by physical inactivity, especially in older individuals.
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http://dx.doi.org/10.1136/bmjdrc-2020-001272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368478PMC
July 2020

Association of habitual alcohol use on risk-taking behaviors while using a car: The Korean National Health and Nutrition Examination Survey 2009-2013.

Accid Anal Prev 2020 Sep 26;144:105651. Epub 2020 Jun 26.

Institute of Health Services Research, Yonsei University, Seoul, South Korea; Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, South Korea.

Background: Using the Alcohol Use Disorders Identification Test-Korean revised version (AUDIT-KR), we examined the association between habitual alcohol use and risk-taking behaviors among car users.

Methods: We used the data of 15,043 car users aged 20 years or older from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted between 2009 and 2013. Multivariable logistic regression analysis was used to investigate the associations between alcohol use and risk-taking behaviors (i.e., driving under the influence of alcohol, riding in a car being driven under the influence, not wearing a seat belt while driving, not wearing a seat belt in the passenger seat), while adjusting for individual-level covariates.

Results: Compared to low-risk drinkers, high-risk drinkers (adjusted odds ratio [Adj.OR] 2.18, 95 % CI 1.96-2.42) and intermediate-risk drinkers (Adj.OR 1.39, 95 % CI 1.26-1.54) had higher odds of risk-taking behaviors while using a car. Stratifying by sociodemographic variables (i.e., sex, age, and region) led to differences in the relationship between alcohol-drinking level and risk-taking behaviors. Furthermore, alcohol-drinking level had significant positive associations with most of risk-taking behaviors, especially driving under the influence of alcohol and using a car with a drunken driver.

Conclusion: Car users with high levels of alcohol consumption are more likely to be involved in risk-taking behaviors, especially in driving under the influence of alcohol. While causal relations cannot be established due to the nature of the cross-sectional design, it is possible that individuals' habitual alcohol consumption level can influence their risk-taking behaviors while using a car.
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http://dx.doi.org/10.1016/j.aap.2020.105651DOI Listing
September 2020

Prevalence of and factors related with abnormal fundoscopic findings among the elderly population in a rural community in South Korea.

Semin Ophthalmol 2020 Jan 6;35(1):41-49. Epub 2020 Feb 6.

Cardiovascular and Metabolic Diseases Etiology Research Center, Seoul, Republic of Korea.

We aimed to report the results of fundus photography ophthalmic examinations among older adults in a rural community in South Korea. We used data from the Korean Social Life, Health, and Aging Project cohort study, which was designed to examine the entire population of individuals aged 60 years or older and their spouses living in a rural of Ganghwa Island, South Korea. At baseline, a total of 860 people was targeted as the study population. From December 2011 to January 2019, five health examinations were conducted, including baseline and follow-up tests. During the fifth wave of the study, we performed fundus photography to assess eye health. Ophthalmic and physical examinations were conducted for 387 people who participated in the fifth wave by trained researchers. Systemic factors were evaluated via blood and diagnostic tests. After excluding , a total of 379 participants was included for analysis. We classified the participants into two groups with either no (zero) or one or more suspicious ophthalmic diseases. The abnormalities included media opacity, suspected glaucoma, and suspicion of retinal disease as diagnosed by trained specialist. We further categorized ophthalmic conditions as clinically insignificant, follow-up needed, semi-urgent, and urgent conditions. We included 379 participants, of which 225 (59.4%) were women. The mean age of the participants was 76.4 ± 6.2 years. Among all participants, 81% (n=307) had one or more abnormalities on fundus screening. Older age, living alone, high blood pressure, and high fasting insulin were associated with an increased risk of having ≥ one eye disease. In terms of triage, 3.7% (n= 14) of the observed conditions were urgent, and 25.9% (n= 98) were semi-urgent. Therefore, we documented fundoscopy results among the elderly population in a rural community in South Korea. Elderly people living alone were more likely to have eye disease. Policies to improve eye health are needed to prevent vision loss in this population.
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http://dx.doi.org/10.1080/08820538.2020.1722182DOI Listing
January 2020

Perceived Discrimination, Depression, and the Role of Perceived Social Support as an Effect Modifier in Korean Young Adults.

J Prev Med Public Health 2019 Nov 24;52(6):366-376. Epub 2019 Oct 24.

Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.

Objectives: The relationships among discrimination, social support, and mental health have mostly been studied in minorities, and relevant studies in the general population are lacking. We aimed to investigate associations between discrimination and depressive symptoms in Korean non-minority young adults, considering the role of social support.

Methods: In total, 372 participants who completed the psychological examinations conducted in the third wave of the Jangseong High School Cohort study were included. We used the Everyday Discrimination Scale to evaluate perceived discrimination and the Beck Depression Inventory-II to measure depressive symptoms. Social support was measured by the Multidimensional Scale of Perceived Social Support. Multivariate linear regression was conducted to investigate associations between discrimination and depression, along with the effect modification of social support. We stratified the population by gender to investigate gender differences.

Results: Perceived discrimination was significantly associated with depressive symptoms (β=0.736, p<0.001), and social support was negatively associated with depression (β=-0.245, p<0.001). In men, support from friends was the most influential factor (β=-0.631, p=0.011), but no significant effect modification was found. In women, support from family was the most influential factor (β=-0.440, p=0.010), and women with higher familial support showed a significantly diminished association between discrimination and depression, unlike those with lower family support.

Conclusions: Discrimination perceived by individuals can lead to depressive symptoms in Korean young adults, and this relationship can may differ by gender and social support status.
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http://dx.doi.org/10.3961/jpmph.19.114DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6893228PMC
November 2019

Effects of Household Income Change on Children's Problem Behavior: Findings From a Longitudinal Study.

J Adolesc Health 2019 10 3;65(4):527-535. Epub 2019 Jul 3.

Institute of Health Services Research, Yonsei University, Seoul, Republic of Korea; Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea. Electronic address:

Purpose: This study aimed to examine the effect of changes in equivalized disposable household income (EHDI) on children's problem behavior.

Methods: Data were collected from the Korean Welfare Panel Study (2006, 2009, 2012). A total of 1,005 school-aged children were included in the analysis. Children's problem behavior was measured using the Korean version of the Child Behavior Checklist. Using the generalized linear mixed model for repeated measures, we investigated the effect of actual household income changes on children's problem behavior, based on the family's EHDI.

Results: Children who experienced high EHDI decrement exhibited a significant increase in problem behavior compared with those who did not experience sizable EHDI change (high decrement: β = .21, standard error = .09, p = .016). Furthermore, problem behavior was higher in girls who experienced a decrement in EHDI compared with boys.

Conclusions: These findings suggest that changes in family's economic status might negatively affect the probability of children's problem behavior when there is a large decrease in EHDI.
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http://dx.doi.org/10.1016/j.jadohealth.2019.05.003DOI Listing
October 2019

Input Shaping Based on an Experimental Transfer Function for an Electrostatic Microscanner in a Quasistatic Mode.

Micromachines (Basel) 2019 Mar 27;10(4). Epub 2019 Mar 27.

School of Mechanical Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.

This paper describes an input shaping method based on an experimental transfer function to effectively obtain a desired scan output for an electrostatic microscanner driven in a quasistatic mode. This method features possible driving extended to a higher frequency, whereas the conventional control needs dynamic modeling and is still ineffective in mitigating harmonics, sub-resonances, and/or higher modes. The performance of the input shaping was experimentally evaluated in terms of the usable scan range (USR), and its application limits were examined with respect to the optical scan angle and frequency. The experimental results showed that the usable scan range is as wide as 96% for a total optical scan angle (total OSA) of up to 9° when the criterion for scan line error is 1.5%. The usable scan ranges were degraded for larger total optical scan angles because of the nonlinear electrostatic torque with respect to the driving voltage. The usable scan range was 90% or higher for most frequencies up to 160 Hz and was drastically decreased for the higher driving frequency because fewer harmonics are included in the input shaping process. Conclusively, the proposed method was experimentally confirmed to show good performance in view of its simplicity and its operable range, quantitatively compared with that of the conventional control.
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http://dx.doi.org/10.3390/mi10040217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6523534PMC
March 2019

Gimbal-Less Two-Axis Electromagnetic Microscanner with Twist Mechanism.

Micromachines (Basel) 2018 May 6;9(5). Epub 2018 May 6.

School of Mechanical Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Korea.

We present an electromagnetically driven microscanner based on a gimbal-less twist mechanism. In contrast to conventional microscanners using a gimbal-less leverage mechanism, our device utilizes a gimbal-less twist mechanism to increase the scan angle in optical applications requiring a large scanning mirror. The proposed gimbal-less scanner with twist mechanism increases the scan angle by 1.55 and 1.97 times for the slow and fast axes, respectively, under the same force; 3.64 and 1.97 times for the slow and fast axes, respectively, under the same maximum stress, compared to the gimbal-less leverage mechanism. The scanner with a 3-mm-diameter mirror and a current path composed of a single-turn coil was fabricated, and it showed the maximum scan angle of 5° (quasi-static) and 22° (resonant) for the slow and fast axes, respectively. The experimentally estimated crosstalk was as small as 0.47% and 0.97% for the fast and slow axes affected by the other axes, respectively, which was determined using a newly employed methodology based on fast Fourier transform.
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http://dx.doi.org/10.3390/mi9050219DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6187665PMC
May 2018

Mesoporous Three-Dimensional Graphene Networks for Highly Efficient Solar Desalination under 1 sun Illumination.

ACS Appl Mater Interfaces 2018 May 26;10(18):15602-15608. Epub 2018 Apr 26.

School of Energy and Chemical Engineering, Low Dimensional Carbon Materials Center , UNIST , Ulsan 44919 , Republic of Korea.

Solar desalination via thermal evaporation of seawater is one of the most promising technologies for addressing the serious problem of global water scarcity because it does not require additional supporting energy other than infinite solar energy for generating clean water. However, low efficiency and a large amount of heat loss are considered critical limitations of solar desalination technology. The combination of mesoporous three-dimensional graphene networks (3DGNs) with a high solar absorption property and water-transporting wood pieces with a thermal insulation property has exhibited greatly enhanced solar-to-vapor conversion efficiency. 3DGN deposited on a wood piece provides an outstanding value of solar-to-vapor conversion efficiency, about 91.8%, under 1 sun illumination and excellent desalination efficiency of 5 orders salinity decrement. The mass-producible 3DGN enriched with many mesopores efficiently releases the vapors from an enormous area of the surface by heat localization on the top surface of the wood piece. Because the efficient solar desalination device made by 3DGN on the wood piece is highly scalable and inexpensive, it could serve as one of the main sources for the worldwide supply of purified water achieved via earth-abundant materials without an extra supporting energy source.
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http://dx.doi.org/10.1021/acsami.7b19584DOI Listing
May 2018

Highly transparent poly(glycidyl methacrylate-co-acryloisobutyl POSS) for 100 μm-thick submicron patterns with an aspect ratio over 100.

Chem Commun (Camb) 2017 Jul;53(58):8172-8175

School of Energy and Chemical Engineering, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.

This is the first report on the fabrication of defect-free submicron structures with more than 100 μm thickness and an aspect ratio over 100. Highly transparent poly(glycidyl methacrylate-co-acryloisobutyl POSS) (PGP) was synthesized via radical polymerization. The mechanical properties of the PGP submicron structure displayed a Young's modulus of 6.09 GPa and a hardness of 0.16 GPa, 4.2 and 8 times, respectively, than those of SU8 nanopatterns. These enhancements enable the utilization of ultrathick 2D-/3D-submicron structures as an ideal platform for microelectromechanical systems, big data storage systems, energy devices, etc.
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http://dx.doi.org/10.1039/c7cc02937cDOI Listing
July 2017

Prevalence of Clostridium perfringens toxin in patients suspected of having antibiotic-associated diarrhea.

Anaerobe 2017 Dec 26;48:34-36. Epub 2017 Jun 26.

Department of Laboratory Medicine, Inje University College of Medicine, Busan, Republic of Korea; Paik Institute for Clinical Research, Inje University College of Medicine, Busan, Republic of Korea. Electronic address:

Background: Although Clostridium perfringens has been reported as a cause of antibiotic-associated diarrhea (AAD), it is uncommon to detect this pathogen in clinical microbiology laboratories in Korea. The aim of this study was to investigate the prevalence of C. perfringens toxin in patients suspected of having AAD.

Methods: A total of 135 stool specimens submitted to a clinical microbiology laboratory for C. difficile toxin assay were tested. We tried to detect both C. difficile and C. perfringens toxins using the Seeplex Diarrhea ACE Detection kit (Seegene, Seoul, Korea). We evaluated the prevalence of 10 bacteria and 5 viruses.

Results: A total of 40 Clostridium spp. were detected in 34 specimens (29.6%). The C. perfringens toxin was detected in 14 of 135 specimens (10.4%), while C. difficile toxin was detected in 26 specimens (19.3%). Other bacteria and viruses, including 8 Aeromonas spp., were detected in 15 specimens. All tests were negative in 92 of the 135 specimens (68.1%).

Conclusion: Clostridium perfringens toxin is relatively common, and we should consider the possibility of its presence in patients suspected of having AAD, especially if C. difficile tests are negative.
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http://dx.doi.org/10.1016/j.anaerobe.2017.06.015DOI Listing
December 2017

Dendrimer-Capped Gold Nanoparticles for Highly Reliable and Robust Surface Enhanced Raman Scattering.

ACS Appl Mater Interfaces 2016 Aug 26;8(31):20379-84. Epub 2016 Jul 26.

Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS) , Ulsan 44919, Republic of Korea.

Dendrimer-stabilized gold nanoparticles (Au-Den) were prepared by a facile solution based method for a highly reliable and robust surface enhanced Raman scattering (SERS) substrate. Au-Den was selectively attached on the surface of reduced graphene oxide (rGO) by noncovalent interactions between the Au capping dendrimer and the graphene surface. Au-Den/rGO exhibits the outstandingly stable and highly magnified Raman signal with an enhancement factor (EF) of 3.9 × 10(7) that enables detection of R6G dyes with concentration as low as 10 nM, retaining 95% of the Raman signal intensity after 1 year. The remarkable stability and enhancement originated not only from a simple combination of the electromagnetic and chemical mechanism of SERS but also from intensified packing density of stable Au-Den on the graphene substrate due to the firm binding between the dendrimer capped metal nanoparticles and the graphene substrate. This method is not limited to the gold nanoparticles and G4 dendrimer used herein, but also can be applied to other dendrimers and metal nanoparticles, which makes the material platform suggested here superior to other SERS substrates.
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http://dx.doi.org/10.1021/acsami.6b05710DOI Listing
August 2016

Hematite-based photoelectrochemical water splitting supported by inverse opal structures of graphene.

ACS Appl Mater Interfaces 2014 Dec 3;6(24):22634-9. Epub 2014 Dec 3.

School of Energy and Chemical Engineering, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Korea.

By coupling α-Fe2O3 with a 3D graphene inverse opal (3D-GIO) conducting electrode, the short diffusion length of carriers and low absorption coefficient in α-Fe2O3 for photoelectrochemical applications were successfully addressed. GIO was directly grown on FTO substrate under low temperature conditions, removing the need for a graphene transfer process. α-Fe2O3 nanoparticles (NPs) were hydrothermally deposited on the surface of GIO, creating α-Fe2O3/GIO. The photocurrent density of α-Fe2O3/GIO in water splitting reactions reached 1.62 mA/cm(2) at 1.5 V vs RHE, which is 1.4 times greater than that of optimized α-Fe2O3. The EIS and IPCE data confirm reduced electron-hole recombination and fast electron transfer processes due to the short distance between active materials and the conducting electrode in the α-Fe2O3/GIO system. Our result may pave the way for designing devices in advanced energy conversion applications as well as a high efficiency hematite-based PEC system.
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http://dx.doi.org/10.1021/am506721aDOI Listing
December 2014

Effect of gross motor group exercise on functional status in chronic stroke: a randomized controlled trial.

J Phys Ther Sci 2014 Jul 30;26(7):977-80. Epub 2014 Jul 30.

Department of Physical Therapy, Sahmyook University, Republic of Korea.

[Purpose] The aim of this study was to understand the effects of task-oriented gross motor group exercise based on motor development on chronic stroke patients' joint, bone, muscle, and motor functions and activities of daily living. [Subjects] Twenty-eight stroke patients hospitalized at P municipal nursing facility for the severely handicapped were randomly assigned to the gross motor group exercise group (experimental group, n=14) or the control group (n=14). [Methods] The two groups performed morning exercise led by a trainer for 30 minutes a day, 5 times a week for 6 weeks in total. The experimental group performed a gross motor group exercise in addition to this exercise for 50 minutes a day, 3 times a week for 6 weeks in total. Before the experiment, all subjects were measured with the Modified Barthel Index (MBI) and for their neuromuscular skeletal and motor-related functions according to the International Classification of Functioning, Disability and Health. [Results] Significant improvements were found in the experimental group's neuromusculoskeletal and motor-related functions and MBI test, except for the stability of joint functions. The control group showed no significant difference from the initial evaluation. [Conclusion] The gross motor group exercise based on motor development is recommended for chronic stroke patients with severe handicaps.
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http://dx.doi.org/10.1589/jpts.26.977DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4135218PMC
July 2014

Optimization of quantum dot-sensitized photoelectrode for realization of visible light hydrogen generation.

Small 2014 Jun 2;10(12):2325-30. Epub 2014 Mar 2.

Interdisciplinary School of Green Energy and Low Dimensional Carbon Materials Center, UNIST, 689-798, Korea.

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http://dx.doi.org/10.1002/smll.201303830DOI Listing
June 2014

Towards visible light hydrogen generation: quantum dot-sensitization via efficient light harvesting of hybrid-TiO2.

Sci Rep 2013 Nov 25;3:3330. Epub 2013 Nov 25.

Interdisciplinary School of Green Energy and Low Dimensional Carbon Materials Center, UNIST, Korea.

We report pronounced enhancement of photoelectrochemical hydrogen generation of a quantum dot-sensitized hybrid-TiO2 (QD/H-TiO2) electrode that is composed of a mesoporous TiO2 layer sandwiched by a double sided energy harvesting layer consisting of a surface-textured TiO2 inverse opals layer on the bottom and a patterned mesoporous TiO2 layer on the top. CdSe/H-TiO2 exhibits a maximum photocurrent density of ~16.2 mA/cm(2), which is 35% higher than that of the optimized control sample (CdSe/P25), achieved by matching of the bandgap of quantum dot-sensitization with the wavelength where light harvesting of H-TiO2 is observed. Furthermore, CdSe/H-TiO2 under filtered exposure conditions recorded current density of ~14.2 mA/cm(2), the greatest value in the visible range. The excellent performance of the quantum dot-sensitized H-TiO2 suggests that alteration of the photoelectrodes to suitable nanostructures with excellent light absorption may offer optimal strategies for attaining maximum efficiency in a variety of photoconversion systems.
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http://dx.doi.org/10.1038/srep03330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3839030PMC
November 2013

Optimization for visible light photocatalytic water splitting: gold-coated and surface-textured TiO2 inverse opal nano-networks.

Nanoscale 2013 Jul 4;5(14):6254-60. Epub 2013 Jun 4.

Interdisciplinary School of Green Energy and Low Dimensional Carbon Materials Center, UNIST, Korea.

A gold nanoparticle-coated and surface-textured TiO2 inverse opal (Au/st-TIO) structure that provides a dramatic improvement of photoelectrochemical hydrogen generation has been fabricated by nano-patterning of TiO2 precursors on TiO2 inverse opal (TIO) and subsequent deposition of gold NPs. The surface-textured TiO2 inverse opal (st-TIO) maximizes the photon trapping effects triggered by the large dimensions of the structure while maintaining the adequate surface area achieved by the small dimensions of the structure. Au NPs are incorporated to further improve photoconversion efficiency in the visible region via surface plasmon resonance. st-TIO and Au/st-TIO exhibit a maximum photocurrent density of ∼0.58 mA cm(-2) and ∼0.8 mA cm(-2), which is 2.07 and 2.86 times higher than that of bare TIO, respectively, at an applied bias of +0.5 V versus an Ag/AgCl electrode under AM 1.5 G simulated sunlight illumination via a photocatalytic hydrogen generation reaction. The excellent performance of the surface plasmon-enhanced mesoporous st-TIO structure suggests that tailoring the nanostructure to proper dimensions, and thereby obtaining excellent light absorption, can maximize the efficiency of a variety of photoconversion devices.
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http://dx.doi.org/10.1039/c3nr01552aDOI Listing
July 2013

Vaccine potential of an attenuated Pasteurella multocida that expresses only the N-terminal truncated fragment of P. multocida toxin in pigs.

Can J Vet Res 2012 Jan;76(1):69-71

College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Republic of Korea.

Previously we described the development of an attenuated Pasteurella multocida mutant that expresses only the N-terminal truncated fragment of P. multocida toxin (N-PMT) and its protective effects in a mouse model. This paper details our evaluation of the vaccine potential of this mutant strain in pigs. Pigs vaccinated with the mutant showed significantly higher rates of antibody induction and lower nasal conchal (turbinate) scores for atrophic rhinitis than controls, which suggests that this mutant strain may be a good candidate for a live attenuated vaccine.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3244291PMC
January 2012

Serodiagnosis of porcine reproductive and respiratory syndrome virus infection with the use of glycoprotein 5 antigens.

Can J Vet Res 2010 Jul;74(3):223-7

Department of Veterinary Medicine, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Republic of Korea.

Glycoprotein 5 (GP5) of porcine reproductive and respiratory syndrome virus (PRRSV) has been studied extensively as a target for vaccine development. This study evaluated the serodiagnostic application of PRRSV GP5 by enzyme-linked immunosorbent assay (ELISA). Two immunodominant peptides (VR #1 and VR #2) and two neutralizing ectodomain-containing peptides (Ecto #1 and Ecto #2), as well as recombinant GP5 (rGP5) as a control, were prepared. Serum from unvaccinated pigs was screened for the antibodies that bind to these peptide and protein antigens. The results were compared with those from a commercially available diagnostic ELISA kit (HerdChek), which uses the nucleocapsid (N) protein as an antigen. Only VR #1+#2 showed a result statistically similar to that of N protein. Ecto #1 and Ecto #2 had a lower sensitivity than VR #1+#2 and rGP5. The peptides and rGP5 showed significant associations with the N protein (P < 0.05 or 0.01), which suggests that GP5 may also be a candidate serodiagnostic antigen. Since antibodies against GP5 persist much longer than those against the N protein, GP5 itself and some of its fragments are thought to be good targets for serodiagnosis. In addition, the presence of antibodies against the PRRSV structural antigens showed significant antigen-dependent differences.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2896805PMC
July 2010