Publications by authors named "Kyoungho Lee"

Objectives: To investigate the association of sarcopenia, exposure to medium-term to long-term ambient particulate matter 2.5 µm and 10 µm (PM and PM) pollution and cognitive function in a community-dwelling cohort of middle-aged and older adults in South Korea.

Design: A community-based prospective cohort study.

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We developed inverted red quantum dot light-emitting diodes (QLEDs) with ZnO nanoparticles synthesized in open and closed systems. Wurtzite-structured ZnO nanoparticles were synthesized using potassium hydroxide and zinc acetate dihydrate at various temperatures in the open and closed systems. The particle size increases with increasing synthesis temperature.

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Objective: Cohort studies on the risk of cognitive impairment in the older population of S. Korea based on glycosylated hemoglobin (HbA1c) levels are exceedingly rare. This study aimed to analyze the association between HbA1c levels and cognitive impairment in older Korean adults without dementia.

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The effect of frailty transition and burden on the risk of all-cause mortality in South Korea remains unclear. This study aimed to investigate the risk of all-cause mortality using the most recent frailty index (FI), changes in FI, and frailty burden. We analyzed data from the Korean Genome and Epidemiology Study (2013-2020).

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This study presents the nutrition survey methods and the updated food composition database for the Korean Genome and Epidemiology Study (KoGES). The KoGES, which is the largest and longest cohort study in Korea, aims to identify genetic and environmental factors associated with chronic diseases. This study has collected dietary data using a validated semi-quantitative food frequency questionnaire and/or the 24-hour recall method.

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Objectives: Late mealtime and short sleep are known to be associated with obesity risk due to a misaligned circadian rhythm. This study aimed to investigate the relationship between obesity and mealtime and sleep duration using the Korean Genome and Epidemiology Study (KoGES) data.

Design: Longitudinally prospective cohort study.

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Background: Air pollution-induced systemic inflammation and oxidative stress are hypothesized to be the major biological mechanisms underlying pathological outcomes. We examined the association between short-term exposure to ambient air pollutants and biomarkers of inflammation and oxidative stress in 2199 general middle-aged Korean population residing in metropolitan areas.

Methods: Serum levels of inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-10, and tumor necrosis factor [TNF]-α) and urinary levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured.

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Article Synopsis
  • Quantum dot light-emitting diodes (QLEDs) often face issues with charge imbalance and exciton quenching when using ZnO nanoparticles as an electron injection layer.
  • To address these problems, an arginine interlayer was added to the ZnO nanoparticles, which improved charge balance by suppressing electron injection and prevented exciton quenching due to its insulating properties.
  • The modified inverted QLEDs with a 20 nm-thick arginine interlayer showed significant improvements in performance, including a 2.22-fold increase in current efficiency and a 2.28-fold increase in external quantum efficiency compared to those without the interlayer.
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Backgruound: To investigate the association between the time-varying resting heart rate (RHR) and change in RHR (∆RHR) over time and the risk of diabetes mellitus (DM) by sex.

Methods: We assessed 8,392 participants without DM or atrial fibrillation/flutter from the Korean Genome and Epidemiology Study, a community-based prospective cohort study that was initiated in 2001 to 2002. The participants were followed up until December 31, 2018.

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Background: Collagen is a key component of connective tissue and has been frequently used in the fabrication of medical devices for tissue regeneration. Human-originated collagen is particularly appealing due to its low immune response as an allograft biomaterial compared to xenografts and its ability to accelerate the regeneration process. Ethically and economically, adipose tissues available from liposuction clinics are a good resource to obtain human collagen.

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Demand is increasing for photovoltaics (PVs) as a result of the development of the Internet of Things and edge computing technologies. As the lighting environment is different for the applications, thus, PVs must be adjustable to various light environments in which systems are installed. PVs should therefore be capable of easily changing their morphology without damaging the cells.

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This paper presents a study that aims to enhance the performance of quantum dot light-emitting didoes (QLEDs) by employing a solution-processed molybdenum oxide (MoO) nanoparticle (NP) as a hole injection layer (HIL). The study investigates the impact of varying the concentrations of the MoO NP layer on device characteristics and delves into the underlying mechanisms that contribute to the observed enhancements. Experimental techniques such as an X-ray diffraction and field-emission transmission electron microscopy were employed to confirm the formation of MoO NPs during the synthesis process.

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199Three-dimensional (3D) scaffolds composed of various biomaterials, including metals, ceramics, and synthetic polymers, have been widely used to regenerate bone defects. However, these materials possess clear downsides, which prevent bone regeneration. Therefore, composite scaffolds have been developed to compensate these disadvantages and achieve synergetic effects.

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Until recent, there are no ideal small diameter vascular grafts available on the market. Most of the commercialized vascular grafts are used for medium to large-sized blood vessels. As a solution, vascular tissue engineering has been introduced and shown promising outcomes.

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Ambient air pollutants reportedly increase inflammatory responses associated with multiple chronic diseases. We investigated the effects of long-term exposure to ambient air pollution on high-sensitivity C-reactive protein (hs-CRP) using data from 60,581 participants enrolled in the Korean Genome and Epidemiology Study-Health Examinees Study between 2012 and 2017. Community Multiscale Air Quality System with surface data assimilation was used to estimate the participants' exposure to criteria air pollutants based on geocoded residential addresses.

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Public concern about the adverse health effects of air pollution has grown rapidly in Korea, and there has been increasing demand for research on ways to minimize the health effects of air pollution. Integrating large epidemiological data and air pollution exposure levels can provide a data infrastructure for studying ambient air pollution and its health effects. The Korean Genome and Epidemiology Study (KoGES), a large population-based study, has been used in many epidemiological studies of chronic diseases.

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Exposure to ambient air pollution and its threat to human health is a global concern, especially in the elderly population. Therefore, more in-depth studies are required to understand the extent of the harmful effects of particulate matter (PM) based on duration and levels of exposure. An investigation was conducted to determine the association between short- (1-14 days), medium- (1, 3, and 6 months), and long-term (1, 2, and 3 years) exposure to air pollutants (PM and PM) and cognitive function among Koreans (4175 participants, mean age 67.

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Prevention strategies for atrial fibrillation (AF) are lacking. This study aimed to identify modifiable risk factors (MRFs) and estimate their impact on AF in the midlife general population. We assessed 9049 participants who were free of prevalent AF at baseline from the Korean Genome and Epidemiology Study.

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Occupational noise is known to be one of the most hazardous risk factors, frequently exceeding the exposure limit thus causing hearing loss and other health outcomes among many field workers in various industries and workplaces. This study aims to characterize the levels of occupational noise exposure during the daily working hours and break periods (sampling preparation and lunch break), identify work-related characteristics affecting the noise exposure levels when including or excluding the break periods and finally determine the most effective approach for occupational noise exposure assessment by using the Korean and U.S.

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A novel harvesting interface for multiple piezoelectric transducers (PZTs) is proposed for high-voltage energy harvesting. Pre-biasing a PZT prior to its mechanical deformation increases its damping force, resulting in higher energy extraction. Unlike the conventional harvesters where a PZT-generated output is assumed to be continuous sinusoidal and output polarity is assumed to be alternating every cycle, PZT-generated output from human motion is expected to be random.

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Among many biomaterials, gelatin methacrylate (GelMA), a photocurable protein, has been widely used in 3D bioprinting process owing to its excellent cellular responses, biocompatibility and biodegradability. However, GelMA still shows a low processability due to the severe temperature dependence of viscosity. To overcome this obstacle, we propose a two-stage temperature control system to effectively control the viscosity of GelMA.

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This study aims to evaluate occupational exposure models by comparing model estimations of Stoffenmanager, version 8.2, and exposure scores calculated using a new exposure model with personal exposure measurements for styrene used in the fiberglass-reinforced plastic (FRP) lamination processes in Korea. Using the collected exposure measurements ( = 160) with detailed contextual information about the type of process, working conditions, local exhaust ventilation, respiratory protections, and task descriptions, we developed a new model algorithm to estimate the score for occupational exposures on situation level.

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Chinese hamster ovary (CHO) cells are used for industrial production of protein-based therapeutics (i.e., "biologics").

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An energy-harvesting interface for kinetic energy harvesting from high-voltage piezoelectric and triboelectric generators is proposed in this paper. Unlike the conventional kinetic energy-harvesting interfaces optimized for continuous sinusoidal input, the proposed harvesting interface can efficiently handle irregular and random high voltage energy inputs. An N-type mosfet (NMOS)-only power stage design is introduced to simplify power switch drivers and minimize conduction loss.

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: A nationwide biomonitoring program identified the long-term trends of environmental exposures to hazardous chemicals in the general population and found geographical locations where body burdens of an exposed group significantly differed from those of the general population. The purpose of this study is to analyze the hazardous compounds associated with foods and cooking in the nationwide general population for evaluation of the environmental exposures and health risk factors and for the establishment of the reference levels at the national level. : During 2009-2010, the National Institute of Food and Drug Safety Evaluation (NIFDS) conducted a nationwide human biomonitoring study, including a questionnaire survey and environmental exposure assessments for specific hazardous compounds from foods and cooking among the general population in South Korea.

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