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1.
BMC Public Health ; 24(1): 1266, 2024 May 08.
Article En | MEDLINE | ID: mdl-38720292

BACKGROUND: Long-term exposure to PM2.5 has been linked to increased mortality risk. However, limited studies have examined the potential modifying effect of community-level characteristics on this association, particularly in Asian contexts. This study aimed to estimate the effects of long-term exposure to PM2.5 on mortality in South Korea and to examine whether community-level deprivation, medical infrastructure, and greenness modify these associations. METHODS: We conducted a nationwide cohort study using the National Health Insurance Service-National Sample Cohort. A total of 394,701 participants aged 30 years or older in 2006 were followed until 2019. Based on modelled PM2.5 concentrations, 1 to 3-year and 5-year moving averages of PM2.5 concentrations were assigned to each participant at the district level. Time-varying Cox proportional-hazards models were used to estimate the association between PM2.5 and non-accidental, circulatory, and respiratory mortality. We further conducted stratified analysis by community-level deprivation index, medical index, and normalized difference vegetation index to represent greenness. RESULTS: PM2.5 exposure, based on 5-year moving averages, was positively associated with non-accidental (Hazard ratio, HR: 1.10, 95% Confidence Interval, CI: 1.01, 1.20, per 10 µg/m3 increase) and circulatory mortality (HR: 1.22, 95% CI: 1.01, 1.47). The 1-year moving average of PM2.5 was associated with respiratory mortality (HR: 1.33, 95% CI: 1.05, 1.67). We observed higher associations between PM2.5 and mortality in communities with higher deprivation and limited medical infrastructure. Communities with higher greenness showed lower risk for circulatory mortality but higher risk for respiratory mortality in association with PM2.5. CONCLUSIONS: Our study found mortality effects of long-term PM2.5 exposure and underlined the role of community-level factors in modifying these association. These findings highlight the importance of considering socio-environmental contexts in the design of air quality policies to reduce health disparities and enhance overall public health outcomes.


Environmental Exposure , Particulate Matter , Humans , Republic of Korea/epidemiology , Particulate Matter/analysis , Particulate Matter/adverse effects , Male , Female , Middle Aged , Adult , Aged , Environmental Exposure/adverse effects , Cohort Studies , Mortality/trends , Air Pollution/adverse effects , Air Pollution/analysis , Air Pollutants/analysis , Air Pollutants/adverse effects , Proportional Hazards Models , Cardiovascular Diseases/mortality
2.
Expert Opin Biol Ther ; : 1-9, 2024 Feb 22.
Article En | MEDLINE | ID: mdl-38349618

BACKGROUND: This study's objective was to demonstrate pharmacokinetic (PK) similarity and safety of denosumab biosimilar, CT­P41, and United States-licensed reference denosumab (US-denosumab) in healthy male Asian adults, considering also pharmacodynamic (PD) outcomes. RESEARCH DESIGN AND METHODS: This double-blind, two-arm, parallel-group, Phase 1 study randomized (1:1) healthy males to a single (60-mg) subcutaneous dose of CT­P41 or US-denosumab. Primary endpoints were area under the concentration - time curve (AUC) from time zero to infinity (AUC0-inf), AUC from time zero to the last quantifiable concentration (AUC0-last), and maximum serum concentration (Cmax). PK equivalence was determined if 90% confidence intervals (CIs) for ratios of geometric least-squares means (gLSMs) were within the predefined 80-125% equivalence margin. Secondary PK, PD, safety, and immunogenicity outcomes were also evaluated. RESULTS: Of 154 participants randomized (76 CT­P41; 78 US-denosumab), 151 received study drug (74 CT­P41; 77 US-denosumab). Primary and secondary PK results, PD results, safety, and immunogenicity were comparable between groups. Ninety percent CIs for ratios of gLSMs were within the predefined equivalence margin for AUC0-inf (100.4-114.7), AUC0-last (99.9-114.3), and Cmax (95.2-107.3). CONCLUSIONS: Following a single dose in healthy males, CT­P41 demonstrated PK equivalence with US-denosumab. TRIAL REGISTRATION: ClinicalTrials.gov: NCT06037395.

3.
Sci Total Environ ; 904: 166874, 2023 Dec 15.
Article En | MEDLINE | ID: mdl-37683874

BACKGROUND: While previous research has identified populations susceptible to non-optimal temperatures, disability has been largely overlooked. Given the growing number of persons with disabilities (PwD) and their social and health disadvantages, understanding how disability intersects with temperature-related health effects is crucial. This study aimed to investigate the associations between non-optimal temperatures and cardiovascular disease (CVD) hospitalization and examine how these associations vary over time considering the existence of disability. METHODS: We used the National Health Insurance Service-National Sample Cohort to investigate the association between non-optimal temperatures and CVD hospitalization in South Korea, 2002-2019. We obtained daily mean temperature from the Korea Meteorological Administration's automated synoptic observing system. We applied a space-time-stratified case-crossover design using a conditional quasi-Poisson regression with a distributed lag non-linear model, adjusting for relative humidity, wind speed, and public holidays. We examined temporal variations in temperature-CVD hospitalization associations using a time window approach. All analyses used the minimum hospitalization temperature (20.0 °C) as reference and were stratified by disability status. RESULTS: The cumulative exposure-response curve in persons without disabilities showed a J-shape with a relative risk (RR) of 1.07 (95 % confidence interval [CI]: 0.99, 1.15) at extreme heat (99th percentile) and 1.09 (95 % CI: 0.97, 1.23) at extreme cold (1st percentile). The cumulative exposure-response curve in PwD showed an M-shape with the highest RR at chill (1.22 [95 % CI: 1.13, 1.32]) and moderate cold temperature (1.11 [95 % CI: 1.01, 1.21]), defined as the 30th and 5th percentiles, respectively. The impacts of heat and cold decreased over time for persons without disabilities but increased for PwD. CONCLUSIONS: Our study found differential temperature-related impacts on CVD hospitalization based on disability status, and PwD were maladapted to heat and cold over time. This suggests the importance of considering disability when investigating temperature-related health disparity and adopting disability-inclusive adaptation strategies.


Cardiovascular Diseases , Disabled Persons , Humans , Cardiovascular Diseases/epidemiology , Cold Temperature , Hospitalization , Hot Temperature , Temperature , Cross-Over Studies
4.
J Neuroimaging ; 33(4): 625-631, 2023.
Article En | MEDLINE | ID: mdl-36972143

BACKGROUND AND PURPOSE: Spontaneous intracranial hypotension (SIH) is a known cause of headaches and neurologic symptoms, but the frequency of cranial nerve symptoms and abnormalities on magnetic resonance imaging (MRI) has not been well described. The purpose of this study was to document cranial nerve findings in patients with SIH and determine the relationship between imaging findings and clinical symptoms. METHODS: Patients diagnosed with SIH with pre-treatment brain MRI at a single institution from September 2014 to July 2017 were retrospectively reviewed to determine the frequency of clinically significant visual changes/diplopia (cranial nerves 3 and 6) and hearing changes/vertigo (cranial nerve 8). A blinded review of brain MRIs before and after treatment was conducted to assess for abnormal contrast enhancement of cranial nerves 3, 6, and 8. Imaging results were correlated with clinical symptoms. RESULTS: Thirty SIH patients with pre-treatment brain MRI were identified. Sixty-six percent of patients had vision changes, diplopia, hearing changes, and/or vertigo. Cranial nerve 3 and/or 6 enhancement was present in nine patients on MRI, with 7/9 patients experiencing visual changes and/or diplopia (odds ratio [OR] 14.9, 95% confidence interval [CI] 2.2-100.8, p = .006). Cranial nerve 8 enhancement was present in 20 patients on MRI, with 13/20 patients experiencing hearing changes and/or vertigo (OR 16.7, 95% CI 1.7-160.6, p = .015). CONCLUSIONS: SIH patients with cranial nerve findings on MRI were more likely to have associated neurologic symptoms than those without imaging findings. Cranial nerve abnormalities on brain MRI should be reported in suspected SIH patients as they may support the diagnosis and explain patient symptoms.


Intracranial Hypotension , Humans , Intracranial Hypotension/complications , Intracranial Hypotension/diagnostic imaging , Retrospective Studies , Diplopia/complications , Clinical Relevance , Magnetic Resonance Imaging/adverse effects , Vertigo/complications , Cranial Nerves/diagnostic imaging , Cranial Nerves/pathology
5.
Environ Pollut ; 314: 120300, 2022 Dec 01.
Article En | MEDLINE | ID: mdl-36181930

Studies on the health effects of long-term ozone exposure remain limited with mixed results. One potential source of this inconsistency is the difference in exposure time metrics. This study aimed to investigate the association between long-term exposure to ambient ozone and mortality in South Korea, using different exposure metrics. We also examined whether heterogeneity between previous studies was due to the different exposure metrics. The study population comprised 179,806 participants from the National Health Insurance Service-National Sample Cohort (2002-2015) residing in seven major cities in South Korea. Several ozone exposure metrics (year-round 24-h, year-round 8-h, warm-season 24-h, and warm-season 8-h) were calculated. Time-varying Cox proportional hazards models were used to estimate the association between ozone and all-cause and cause-specific mortalities. Random-effect meta-analysis and meta-regression analysis were performed to pool the effect estimates of previous studies and examine whether the exposure metric can explain the between-study heterogeneity. The hazard ratios (HRs) per 10 ppb increment in year-round 24-h ozone for all-cause (HR, 1.18; 95% CI, 1.07-1.29) and circulatory (HR, 1.52; 95% CI, 1.25-1.84) mortality were higher than those of the other metrics. Year-round 8-h ozone exhibited the largest association with respiratory mortality (HR, 1.43; 95% CI, 1.04-1.96). A meta-analysis of 29 previous studies and the present study showed the largest HR for all-cause mortality from studies using year-round 8-h exposure (HR, 1.014; 95% CI, 0.994-1.033). The exposure metric was significantly associated with effect estimates in the multivariable meta-regression model. In conclusion, in the population-based cohort in South Korea, we found positive associations between several long-term ozone exposure metrics and mortality. The different ozone exposure metrics exhibited heterogeneous effect estimates. A year-round 24-h average ozone metric also could be considered an alternative long-term standard for ozone.


Air Pollutants , Air Pollution , Ozone , Humans , Ozone/analysis , Air Pollution/adverse effects , Air Pollution/analysis , Air Pollutants/analysis , Environmental Exposure/analysis , Seasons , Mortality , Particulate Matter/analysis
6.
J Neuroimaging ; 32(6): 1185-1192, 2022 11.
Article En | MEDLINE | ID: mdl-36045502

BACKGROUND AND PURPOSE: High-grade glioma (HGG), including glioblastoma, is the most common primary brain neoplasm and has a dismal prognosis. After initial treatment, follow-up decisions are guided by longitudinal MRI performed at routine intervals. The Brain Tumor Reporting and Data System (BT-RADS) is a proposed structured reporting system for posttreatment brain MRIs. The purpose of this study is to determine the relationship between BT-RADS scores and overall survival in HGG patients. METHODS: Chart review of grade 4 glioma patients who had an MRI at a single institution from November 2018 to November 2019 was performed. BT-RADS scores, tumor characteristics, and overall survival were recorded. Likelihood of improvement, stability, or worsening on the subsequent study was calculated for each score. Survival analysis was performed using Kaplan-Meier method, log-rank test, and a time-dependent cox model. Significance level of .05 was used. RESULTS: The study identified 91 HGG patients who underwent a total of 538 MRIs. Mean age of patients was 57 years old. Score with the highest likelihood for worsening on the next follow-up was 3b. The risk of death was 53% higher with each incremental increase in BT-RADS scores (hazard ratio, 1.53; 95% confidence interval [CI], 1.07-2.19; p = .019). The risk of death was 167% higher in O-6-methylguanine-DNA-methyltransferase unmethylated tumors (hazard ratio, 2.67; 95% CI, 1.34-5.33; p = .005). CONCLUSIONS: BT-RADS scores can be used as a reference guide to anticipate whether patients' subsequent MRI will be improved, stable, or worsened. The scoring system can also be used to predict clinical outcomes and prognosis.


Brain Neoplasms , Glioblastoma , Glioma , Humans , Middle Aged , Glioma/diagnostic imaging , Glioma/pathology , Brain Neoplasms/pathology , Prognosis , Magnetic Resonance Imaging , Retrospective Studies
7.
Sci Total Environ ; 848: 157717, 2022 Nov 20.
Article En | MEDLINE | ID: mdl-35926615

Persons with disabilities (PwD), the world's largest minority, can be more susceptible to particulate matter (PM) than persons without disabilities. Although numerous studies have addressed population susceptibility to PM, PwD have not been studied in air pollution epidemiology. This study investigated the association between short-term exposure to PM with an aerodynamic diameter smaller than 10 µm (PM10) and cardiovascular hospital admissions by the existence of a disability, while also considering intersections of disability and other socio-demographic characteristics in South Korea. We used the National Health Insurance Service-National Sample Cohort (NHIS-NSC) to investigate the association between short-term exposure to PM10 and cardiovascular hospital admissions in seven metropolitan cities from 2002 to 2015. We conducted a time-stratified case-crossover analysis using conditional logistic regression and adjusted for daily temperature, relative humidity, air pressure, and national holidays. We conducted stratified analyses according to the existence of a disability, disability type and severity, and socio-demographic characteristics. The results showed that a 10 µg/m3 increase in the 0-3 moving average level of PM10 was associated with 1.9 % (95 % confidence interval [CI]: 0.7 %, 3.2 %) and 0.0 % (95 % CI: -0.5 %, 0.5 %) increase in cardiovascular admissions in persons with and without disabilities, respectively. Among PwD, the associations were pronounced in people with brain lesion disorders (percent change [PC]: 2.7 %, 95 % CI: 0.5 %, 5.0 %), people with visual impairment (PC: 3.0 %, 95 % CI: -1.0 %, 7.1 %), and people with severe disability (PC: 3.0 %, 95 % CI: 0.9 %, 5.0 %). We found that PwD may be more adversely affected by PM10 than their non-disabled counterparts. This suggests that PwD is a social identity reflecting the socially marginalized and disadvantaged population in air pollution epidemiology.


Air Pollutants , Air Pollution , Disabled Persons , Air Pollutants/analysis , Air Pollution/analysis , Hospitalization , Humans , Particulate Matter/analysis
8.
BMJ Open ; 12(4): e058903, 2022 04 12.
Article En | MEDLINE | ID: mdl-35414561

OBJECTIVES: To understand a 20-year trend of gender-specific smoking prevalence among adults in South Korea. DESIGN: Age-period-cohort analysis using the intrinsic estimator method was applied to examine the separate contribution of age, period and cohort effect on smoking prevalence. The Driving Force-Pressure-State-Exposure-Effect-Action (DPSEEA) framework was used to explain the observed smoking trends by mapping potential determinants and to address policy implications. SETTING: General adult population in South Korea. PARTICIPANTS: 34 828 men and 43 632 women who aged 19-78 years, were not currently pregnant and were without a prior diagnosis of cardiovascular disease or cancer. OUTCOME MEASURES: Gender-specific current smoking prevalence using the 1998-2017 Korea National Health and Nutrition Examination Survey. RESULTS: Our results showed gender-specific age and birth cohort effects. More specifically, the smoking prevalence peaked at their mid-20s (prevalence rate ratio (PRR): 1.54, 95% CI: 1.49 to 1.59) and cohort born in 1959-1963 (PRR: 1.63, 95% CI: 1.57 to 1.70) and then decreased in men. On the other hand, in women, the smoking prevalence consistently increased until their mid-40s (PRR: 1.53, 95% CI: 1.27 to 1.84) and in recent birth cohort groups (PRR in 1994-1998 cohort: 1.55, 95% CI: 1.13 to 2.13). The period effects declined from 1998-2002 to 2003-2007, following increasing fluctuations in both genders. The smoking-DPSEEA framework showed the absence of policy actions to target female smokers and emphasised a proactive approach that tackles the upstream causes for smoking in women. CONCLUSIONS: Men and women are clearly in different phases of the smoking epidemic in Korean population, and gender-tailored policies should be implemented.


Nicotiana , Tobacco Products , Adult , Cohort Studies , Female , Humans , Male , Middle Aged , Nutrition Surveys , Pregnancy , Prevalence , Republic of Korea/epidemiology
9.
Article En | MEDLINE | ID: mdl-35206592

Bone health is a major concern for aging populations globally. Osteoporosis and bone mineral density are associated with air pollution, but less is known about the impacts of air pollution on osteoporotic fracture. We aimed to assess the associations between long-term air pollution exposure and risk of osteoporotic fracture in seven large Korean cities. We used Cox proportional hazard models to estimate hazard rations (HRs) of time-varying moving window of past exposures of particulate matter (PM10), sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), and ozone (O3) for osteoporotic fracture in Korean adults (age ≥ 50 years) in the National Health Insurance Service-National Sample Cohort data, followed 2002 to 2015. HRs were calculated for an interquartile range (IQR) increase. Comorbidity and prescription associated with osteoporosis, age, sex, body mass index, health behaviors, and income were adjusted in the models. Effect modification by age, sex, exercise, and income was examined. We assessed 56,467 participants over 535,481 person-years of follow up. Linear and positive exposure-response associations were found for SO2, while PM10 and NO2 showed nonlinear associations. SO2 was associated with osteoporosis-related fracture with marginal significance (HR for an IQR [2 ppb] increase = 1.04, 95% CI: 1.00, 1.09). The SO2 HR estimates were robust in analyses applying various moving windows of exposure (from one to three years of past exposure) and two-pollutant models. The central HR estimate of O3 implied positive associations but was not significant (HR for 0.007 ppm increase = 1.01, 95% CI: 0.97, 1.06). PM10, CO, and NO2 did not show associations. Vulnerable groups by sex, age, exercise, and income varied across air pollutants and there was no evidence of effect modifications. Long-term exposure to SO2, but not PM10, CO, NO2 and O3, was associated with increased osteoporotic fracture risks in Korean adults.


Air Pollutants , Air Pollution , Osteoporosis , Osteoporotic Fractures , Ozone , Republic of Korea , Adult , Air Pollutants/analysis , Air Pollutants/toxicity , Air Pollution/adverse effects , Air Pollution/analysis , Cohort Studies , Environmental Exposure/adverse effects , Environmental Exposure/analysis , Humans , Middle Aged , Nitrogen Dioxide/analysis , Osteoporosis/epidemiology , Osteoporotic Fractures/epidemiology , Ozone/analysis , Particulate Matter/adverse effects , Particulate Matter/analysis , Republic of Korea/epidemiology , Sulfur Dioxide/analysis , Sulfur Dioxide/toxicity
10.
Nanoscale Res Lett ; 17(1): 26, 2022 Feb 10.
Article En | MEDLINE | ID: mdl-35142901

Transition metal dichalcogenides have attracted renewed interest for use as thermoelectric materials owing to their tunable bandgap, moderate Seebeck coefficient, and low thermal conductivity. However, their thermoelectric parameters such as Seebeck coefficient, electrical conductivity, and thermal conductivity are interdependent, which is a drawback. Therefore, it is necessary to find a way to adjust one of these parameters without affecting the other parameters. In this study, we investigated the effect of helium ion irradiation on MoSe2 thin films with the objective of controlling the Seebeck coefficient and electrical conductivity. At the optimal irradiation dose of 1015 cm-2, we observed multiple enhancements of the power factor resulting from an increase in the electrical conductivity, with slight suppression of the Seebeck coefficient. Raman spectroscopy, X-ray diffraction, and transmission electron microscopy analyses revealed that irradiation-induced selenium vacancies played an important role in changing the thermoelectric properties of MoSe2 thin films. These results suggest that helium ion irradiation is a promising method to significantly improve the thermoelectric properties of two-dimensional transition metal dichalcogenides. Effect of He+ irradiation on thermoelectric properties of MoSe2 thin films.

11.
Foods ; 10(9)2021 Aug 26.
Article En | MEDLINE | ID: mdl-34574110

Advanced glycation end-products (AGEs) such as methylglyoxal (MGO) play a vital role in the pathogenesis of nephropathy, a diabetic complication. In the present study, we evaluated the anti-glycation and renal protective properties of Ishige okamurae extract (IOE) against AGE-induced oxidative stress. HPLC analysis confirmed that bioactive phlorotannins such as diphlorethohydroxycarmalol and ishophloroglucin A are predominantly present in IOE. IOE showed strong anti-glycation activities via inhibition of AGE formation, inhibition of AGE-protein cross-linking, and breaking of AGE-protein cross-links. In addition, in vitro studies using mesangial cells demonstrated that IOE effectively suppressed intracellular reactive oxygen species production, intracellular MGO accumulation, and apoptotic cell death by MGO-induced oxidative stress, in addition to regulating the expression of proteins involved in the receptor for AGEs and nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response elements (ARE) signaling pathways. Therefore, IOE can serve as a natural therapeutic agent for the management of AGE-related nephropathy.

12.
Int J Biol Macromol ; 188: 245-252, 2021 Oct 01.
Article En | MEDLINE | ID: mdl-34384800

To increase the value of yeast-fermented Korean liquor by-products, we obtained crude polysaccharide (CPS) fractions via ultrasound-assisted extraction and stepwise-gradient ethanol precipitation and investigated their functionality. Nitric oxide production in RAW 264.7 cells was increased following treatment with the CPSs derived from extract. Analysis of the monosaccharide and amino acid composition of the CPS fractions using HPLC revealed that the polysaccharides were mainly composed of glucose (57.2%), mannose (22.6%), and galactose (17.6%), and no amino acids were detected. In addition, a higher concentration of ethanol solvent for fractionation yielded polysaccharides with lower molecular weights (<15 kDa). CPS 3 and 4 fractions increased the production of TNF-α (15 and 17-fold, respectively) and IL-6 (20 and 18-fold, respectively) and iNOS (65 and 35-fold, respectively) expression at concentration 12.5 µg/mL compared with levels in non-treated RAW 264.7 cells. Especially, CPS 4 at 200 and 400 µg/mL significantly increased the proliferation of mouse spleen cells by 126% and 153%, respectively. These results indicated that CPS 4 enhanced the proliferation of mouse spleen cells in vivo, indicating its immune-enhancing effects. Therefore, this research can contribute to the development of eco-friendly extraction techniques and immune-enhancing materials.


Monosaccharides/chemistry , Polysaccharides/chemistry , Saccharomyces cerevisiae/chemistry , Animals , Chemical Fractionation , Fermentation/drug effects , Mice , Molecular Weight , Monosaccharides/pharmacology , Nitric Oxide/chemistry , Nitric Oxide Synthase Type II/genetics , Polysaccharides/pharmacology , RAW 264.7 Cells , Republic of Korea , Saccharomyces cerevisiae/genetics , Tumor Necrosis Factor-alpha/genetics
13.
Plant Foods Hum Nutr ; 76(3): 326-333, 2021 Sep.
Article En | MEDLINE | ID: mdl-34279786

This study comprehensively presents the relationship between the bioactive substance of 70% (v/v) aqueous ethanol extract of 38 species of seaweeds (SWEs), and anti-glycation activities. The contents of bioactive substance of SWEs, such as total phenolic, total flavonoid and condensed tannins, were determined through a colorimetric analysis. Among the tested species, Ecklonia bicyclis, Ishige foliacea, and Cladophora urightiana var. minor had the highest amount of total phenolic (255.75 mg GAE/g DW), total condensed tannins (63.36 mg CE/g DW), and total flavonoid content (85.26 mg CE/g DW), respectively. Anti-glycation properties of SWEs were evaluated through advanced glycation end-products (AGEs) formation, AGEs-collagen cross-link formation, and AGEs-collagen cross-link breaking assay. Brown algae species exhibited a more prominent inhibitory activity on AGEs formation and AGEs-collagen cross-links, and the breaking of AGEs-collagen cross-links compared to that exhibited by aminoguanidine and ALT-711 (positive controls). Using principal component analysis, we confirmed that the AGEs formation inhibitory property and AGEs-collagen cross-links breaking activity were closely correlated with total phenolic and the condensed tannin contents contained in SWEs. Therefore, the bioactive substances such as phenolics and condensed tannins in seaweeds can be used as predictive indices in selecting compounds for the development of a therapeutic agent that prevents diabetic complications related to the AGEs. In addition, our results suggest that brown algae species, which contains more bioactive substances than green and red algae species, can be utilized as a promising natural resource for the prevention and alleviation of AGEs-related diabetic complications as AGE inhibitor and cross-links breaker.


Glycation End Products, Advanced , Seaweed , Phenols , Plant Extracts/pharmacology , Principal Component Analysis
14.
Nanotechnology ; 32(31)2021 May 12.
Article En | MEDLINE | ID: mdl-33892483

Hexagonal boron nitride (hBN) is one of the most suitable 2D materials for supporting graphene in electronic devices, and it plays a fundamental role in screening out the effect of charge impurities in graphene in contrast to inhomogeneous supports such as silicon dioxide (SiO2). Although many interesting surface science techniques such as scanning tunneling microscopy (STM) revealed dielectric screening by hBN and emergent physical phenomena were observed, STM is only appropriate for graphene electronics. In this paper, we demonstrate the dielectric screening by hBN in graphene integrated on a silicon photonic waveguide from the perspective of a near-field scanning optical microscopy (NSOM) and Raman spectroscopy. We found shifts in the Raman spectra and about three times lower slope decrease in the measured electric near-field amplitude for graphene on hBN relative to that for graphene on SiO2. Based on finite-difference time-domain simulations, we confirm lower electric field slope and scattering rate in graphene on hBN, which implies dielectric screening, in agreement with the NSOM signal. Graphene on hBN integrated on silicon photonics can pave the way for high-performance hybrid graphene photonics.

15.
Antioxidants (Basel) ; 10(1)2021 Jan 14.
Article En | MEDLINE | ID: mdl-33466809

Oxidative stress, caused by the excessive production of reactive oxygen species (ROS), results in cellular damage. Therefore, functional materials with antioxidant properties are necessary to maintain redox balance. Turmeric leaves (Curcuma longa L. leaves; TL) are known to have antioxidant properties, including 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-Azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), and Hydrogen peroxide (H2O2) radical scavenging activity in several studies. The antioxidant effects of TL come from distinct bioactive compounds, such as curcumin, total phenolic compounds, and flavonoids. Therefore, in this study, the antioxidant effects of a water extract of TL (TLE) against H2O2 treatment were assessed in vitro Vero cells and in vivo zebrafish models. The intracellular ROS generation and the proportion of sub-G1 phase cells were evaluated in H2O2- or/and TLE-treated Vero cells to measure the antioxidant activity of TLE. TLE showed outstanding intracellular ROS scavenging activity and significantly decreased the proportion of cells in the sub-G1 phase in a dose-dependent manner. Furthermore, cell death, ROS generation, and lipid peroxidation in the H2O2-treated zebrafish model were attenuated as a consequence of TLE treatment. Collectively, the results from this study suggested that TLE may be an alternative material to relieve ROS generation through its antioxidant properties or a suitable material for the application in a functional food industry.

16.
Curr Probl Diagn Radiol ; 50(3): 356-361, 2021.
Article En | MEDLINE | ID: mdl-32081518

BACKGROUND: The Brain Tumor Reporting and Data System (BT-RADS) is a proposed standardized radiology reporting scheme for magnetic resonance imagings in brain tumor patients. A website was created to introduce the classification system and to promote its use during daily radiology readouts with trainees. OBJECTIVES: To demonstrate how a website can help implement a structured reporting at a tertiary academic facility. METHODS: A website, www.btrads.com, including visual aids and an interactive scoring tool was developed to educate trainees about a structured reporting system for brain tumor magnetic resonance imagings. Number of website visitors, resource downloads, and scoring tool users was gathered during the study period of May 1, 2018 to April 30, 2019. Authors surveyed a group of 71 radiology trainees and 34 faculty physicians who care for brain tumor patients to assess the perceived educational and clinical value of BT-RADS. RESULTS: The website was visited by 10,058 unique users in 1 year. The most commonly downloaded support material was the full guide (382 downloads). The interactive scoring tool was used 267 times. The use of BT-RADS at a single institution over 12 months reached over 70%. While survey results from trainees did not reach statistical significance, faculty oncologists, neurosurgeons, and radiologists felt that BT-RADS was a valuable clinical tool that improved interdisciplinary communication, facilitated educational discussions, and helped make treatment decisions. CONCLUSIONS: A website designed to implement a novel structured radiology report facilitated template acceptance across a large neuroradiology section. Groups seeking to modify reporting practices should consider using a website.


Brain Neoplasms , Radiology Information Systems , Radiology , Brain Neoplasms/diagnostic imaging , Humans , Magnetic Resonance Imaging , Radiologists
17.
Adv Mater ; 33(1): e2005742, 2021 Jan.
Article En | MEDLINE | ID: mdl-33241603

The classical Fermi liquid theory and Drude model have provided fundamental ways to understand the resistivity of most metals. The violation of the classical theory, known as non-Fermi liquid (NFL) transport, appears in certain metals, including topological semimetals, but quantitative understanding of the NFL behavior has not yet been established. In particular, the determination of the non-quadratic temperature exponent in the resistivity, a sign of NFL behavior, remains a puzzling issue. Here, a physical model to quantitatively explain the Lifshitz transition and NFL behavior in highly doped (a carrier density of ≈1022 cm-3 ) monoclinic Nb2 Se3 is reported. Hall and magnetoresistance measurements, the two-band Drude model, and first-principles calculations demonstrate an apparent chemical potential shift by temperature in monoclinic Nb2 Se3 , which induces a Lifshitz transition and NFL behavior in the material. Accordingly, the non-quadratic temperature exponent in the resistivity can be quantitatively determined by the chemical potential shift under the framework of Fermi liquid theory. This model provides a new experimental insight for nontrivial transport with NFL behavior or sign inversion of Seebeck coefficients in emerging materials.

18.
Environ Res ; 192: 110290, 2021 01.
Article En | MEDLINE | ID: mdl-33027629

Evidence from cohort studies on the effects of long-term exposure to air pollution on mortality is limited in South Korea, which has high concentration of particles compared to North America, Western Europe, and Japan, and low exposure compared to China. To reduce knowledge gaps between other countries and South Korea, we investigated the association between all-cause, cardiovascular, and respiratory mortality and long-term exposure to PM10 and, as a surrogate for fine particles from local emission sources, SO2 and NO2. Participants comprised 18,220 subjects (97,114.4 person-years) residing in 73 districts of seven major cities of South Korea who were assigned to measurements of fixed-site monitoring stations and followed up. We applied Cox proportional hazard models with time-varying exposure up to three years average of air pollutants. We adjusted for individual and district-level covariates measured at baseline such as age, sex, socioeconomic positions, and health behaviors. We found that hazard ratios of PM10 and SO2 for all-cause mortality leveled off over approximately 5 ppb of SO2 and 35-50 µg/m3 of PM10. Interquartile range increases of PM10 (5.05 µg/m3), SO2 (2.09 ppb), and NO2 (11.41 ppb) were associated with 14.4% (95% CI: -0.4, 31.4), 18.1% (-4.5, 46.0), and 18.9% (-8.7, 54.7) increases in cardiovascular mortality, respectively. We did not find positive associations for respiratory mortality. The increase in cardiovascular mortality varied by sex (for PM10, in females, 27.4% (5.8, 53.5) increase), smoking (in non-smokers, 35.9% (12.7, 64.0) increase), drinking (in drinkers, 24.5% (2.1, 51.8) increase), marital status (in those not married, 23.1% (1.1, 49.9)), employment status (for SO2, in those employed, 79.4% (16.1, 177.3) increase), body mass index (in those ≥23, 47.6% (10.4, 97.3) increase), and community deprivation (for PM10, in less deprived communities, 21.0% (1.3, 44.4) increase). In summary, long-term exposure to air pollution is associated with mortality risk in South Korea. Our results suggest that the health effect of long-term exposure to air pollution may not be equal by sex, health behaviors and socioeconomic positions.


Air Pollutants , Air Pollution , Cardiovascular Diseases , Air Pollutants/analysis , Air Pollutants/toxicity , Air Pollution/adverse effects , Air Pollution/analysis , Cause of Death , China , Cities , Environmental Exposure/adverse effects , Environmental Exposure/analysis , Europe , Female , Follow-Up Studies , Humans , Japan , North America , Particulate Matter/analysis , Particulate Matter/toxicity , Republic of Korea/epidemiology , Time Factors
19.
BJR Case Rep ; 6(2): 20190070, 2020 Sep.
Article En | MEDLINE | ID: mdl-33029363

A 44-year-old male initially presented with a right thalamic brain tumor that was confirmed with stereotactic biopsy to be glioblastoma (GBM). The patient was treated with radiotherapy and temozolomide for 6 weeks. At 1 month after completing chemoradiation therapy, the patient underwent follow-up imaging that revealed the primary lesion had mildly responded to chemoradiation, but a secondary lesion had developed along the biopsy needle tract. This secondary lesion was outside of the field of radiation therapy for the primary tumor and concluded to be intracranial spread of GBM along the biopsy tract. The patient's final imaging 4 months after initial diagnosis revealed the primary and secondary lesions had enlarged. Subsequently, the patient clinically deteriorated and died 7 months after initial diagnosis.

20.
Article En | MEDLINE | ID: mdl-32967243

Previous studies have consistently reported an increase in mortality risk, even at low levels of blood lead. The average blood lead concentration in the Korean population has steadily decreased but is still higher than that of developed countries. The purpose of this study was to examine the associations between mortality and blood lead concentrations for adults in Korea. We used the Korea National Health and Nutrition Examination Survey (2008-2013) linked Cause of Death data, which are followed by 2018. A total of 7308 subjects who aged over 30 at the baseline examination were included in the analyses. Cox proportional hazard model was used to estimate the hazard ratios of mortality from non-accidental causes and cancer mortality. The estimated hazard ratios (95% CI) for comparison of the second and third tertile group with the lowest tertile group were 2.01 (1.20, 3.40) and 1.91 (1.13, 3.23) for non-accidental mortality and 3.42 (95% CI: 1.65, 7.08) and 2.27 (95% CI: 1.09, 4.70) for cancer mortality, respectively. The dose-response relationship also showed significant increase in the risk of mortality at blood lead level between 1.5 and 6.0 µg/dL. Our findings suggest that potent policies to lower lead exposure are required for the general Korean population.


Lead , Mortality , Nutrition Surveys , Adult , Female , Follow-Up Studies , Humans , Lead/blood , Lead/toxicity , Male , Mortality/trends , Proportional Hazards Models , Republic of Korea/epidemiology
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