Chungnam National University
  • Daejeon, South Korea
Recent publications
Chronic obstructive pulmonary disease (COPD) has been regarded as a disease of smokers, but the prevalence of non-smoking COPD patients have been reported to be considerable. We investigated differences in clinical characteristics between smoking and non-smoking COPD patients. We used data from the Korea COPD Subgroup Study (KOCOSS) database, which is a multicenter cohort that recruits patients from 54 medical centres in Korea. Comprehensive comparisons of smoking and non-smoking COPD patients were performed based on general characteristics, exacerbations, symptom scores, radiological findings, and lung-function tests. Of the 2477 patients included in the study, 8.1% were non-smokers and 91.9% were smokers. Non-smoking COPD patients were more likely to be female and to have a higher body mass index and lower level of education. Non-smoking COPD patients had more comorbidities, including hypertension, osteoporosis, and gastroesophageal reflux disease, and experienced more respiratory and allergic diseases. No significant differences in exacerbation rates, symptom scores, or exercise capacity scores were observed between the two groups. Smoking COPD patients had more emphysematous lung according to the radiological findings, and non-smoking patients had more tuberculosis-destroyed lung and bronchiectasis. Lung-function testing revealed no significant difference in the forced expiratory capacity in 1 sec between the two groups, but smokers had more rapid lung-function decline in the 5 years of follow-up data. We found differences in general characteristics and radiological findings between smoking and non-smoking COPD patients. No significant differences in exacerbation or symptom scores were observed, but decline in lung function was less steep in non-smoking patients.Supplemental data for this article is available online at .
Megadroughts represent droughts with a high-intensity, long-lasting duration, and extensive spatial extent. However, as these characteristics have not been quantitatively proposed, a reasonable guideline for identifying megadroughts has not been determined. This study aims to identify the quantitative characteristics of a megadrought and suggest a guideline for detecting the occurrence of the megadrought. This study focused on the central Chile megadrought that occurred from 2010 to 2016 in central Chile. The megadrought was analyzed using the standardized precipitation index (SPI) while increasing its timescale. The 60-month timescale spatially represented that more than 60% of all stations in central Chile experienced a drought indicating moderate or more drought intensity (SPI ≤ −1) for a long duration of more than 36 months in the megadrought period. Then, guidelines were suggested based on the timescale, drought intensity, and spatial extent of drought as the criteria to detect the occurrence of the megadrought. In the criteria of moderate or more drought intensity and the spatial extent of 50% or 60%, the 60-month timescale detected the occurrence of the megadrought the earliest and most appropriately. This study will be used as a useful guideline to define and detect megadroughts that will occur in the future. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Nontuberculous mycobacterial pulmonary diseases (NTM-PDs) are emerging as global health threats with issues of antibiotic resistance. Accumulating evidence suggests that the gut-lung axis may provide novel candidates for host-directed therapeutics against various infectious diseases. However, little is known about the gut-lung axis in the context of host protective immunity to identify new therapeutics for NTM-PDs. This study was performed to identify gut microbes and metabolites capable of conferring pulmonary immunity to NTM-PDs. Using metabolomics analysis of sera from NTM-PD patients and mouse models, we showed that the levels of l-arginine were decreased in sera from NTM-PD patients and NTM-infected mice. Oral administration of l-arginine significantly enhanced pulmonary antimicrobial activities with the expansion of IFN-γ-producing effector T cells and a shift to microbicidal (M1) macrophages in the lungs of NTM-PD model mice. Mice that received fecal microbiota transplants from l-arginine-treated mice showed increased protective host defense in the lungs against NTM-PD, whereas l-arginine-induced pulmonary host defense was attenuated in mice treated with antibiotics. Using 16S rRNA sequencing, we further showed that l-arginine administration resulted in enrichment of the gut microbiota composition with Bifidobacterium species. Notably, oral treatment with either Bifidobacterium pseudolongum or inosine enhanced antimicrobial pulmonary immune defense against NTM infection, even with multidrug-resistant clinical NTM strains. Our findings indicate that l-arginine-induced gut microbiota remodeling with enrichment of B. pseudolongum boosts pulmonary immune defense against NTM infection by driving the protective gut-lung axis in vivo.
Patients with a biopsy diagnosis of ductal carcinoma in situ (DCIS) may be diagnosed with invasive breast cancer after excision. We evaluated the preoperative clinical and imaging predictors of DCIS that were associated with an upgrade to invasive carcinoma on final pathology and also compared the diagnostic performance of various statistical models. We reviewed the medical records; including mammography, ultrasound (US), and magnetic resonance imaging (MRI) findings; of 644 patients who were preoperatively diagnosed with DCIS and who underwent surgery between January 2012 and September 2018. Logistic regression and three machine learning methods were applied to predict DCIS underestimation. Among 644 DCIS biopsies, 161 (25%) underestimated invasive breast cancers. In multivariable analysis, suspicious axillary lymph nodes (LNs) on US (odds ratio [OR], 12.16; 95% confidence interval [CI], 4.94–29.95; P < 0.001) and high nuclear grade (OR, 1.90; 95% CI, 1.24–2.91; P = 0.003) were associated with underestimation. Cases with biopsy performed using vacuum-assisted biopsy (VAB) (OR, 0.42; 95% CI, 0.27–0.65; P < 0.001) and lesion size <2 cm on mammography (OR, 0.45; 95% CI, 0.22–0.90; P = 0.021) and MRI (OR, 0.29; 95% CI, 0.09–0.94; P = 0.037) were less likely to be upgraded. No significant differences in performance were observed between logistic regression and machine learning models. Our results suggest that biopsy device, high nuclear grade, presence of suspicious axillary LN on US, and lesion size on mammography or MRI were independent predictors of DCIS underestimation.
The growing interest in the anaerobic ammonium oxidizing (AMX) process in treating high nitrogen containing wastewaters and a comprehensive study into the granulation mechanism of these bacteria under diverse environmental conditions over the years have been unequal. To this effect, the distinctive differences in saline adapted AMX (S_AMX) and non-saline adapted AMX (NS_AMX) granules are presented in this study. It was observed that substrate utilisation profiles, granule formation mechanism, and pace towards granulation differed marginally for the two adaptation conditions. The different microbial dominant aggregation types aided in splitting the 471 days operated lab-scale SBRs into three distinct phases. In both reactors, phase III (granules dominant phase) showed the highest average nitrogen removal efficiency of 87.9% ± 4.8% and 85.6% ± 3.6% for the S_AMX and NS_AMX processes, respectively. The extracellular polymeric substances (EPS) quantity and major composition determined its role either as a binding agent in granulation or a survival mechanism in saline adaptation. It was also observed that granules of the S_AMX reactor were mostly loosely and less condensed aggregates of smaller sub-units and flocs while those of the NS_AMX reactor were compact agglomerates. The ionic gradient in saline enrichment led to an increased activity of the Na⁺/K⁺ – ATPase, hence enriched granules produced higher cellular adenosine triphosphate molecules which finally improved the granules active biomass ratio by 32.96%. Microbial community showed that about three to four major known AMX species made up the granules consortia in both reactors. Proteins and expression of functional genes differed for these different species.
Prime editing can induce a desired base substitution, insertion, or deletion in a target gene using reverse transcriptase after nick formation by CRISPR nickase. In this study, we develop a technology that can be used to insert or replace external bases in the target DNA sequence by linking reverse transcriptase to the Francisella novicida Cas9, which is a CRISPR-Cas9 ortholog. Using FnCas9(H969A) nickase, the targeting limitation of existing Streptococcus pyogenes Cas9 nickase [SpCas9(H840A)]-based prime editing is dramatically extended, and accurate prime editing is induced specifically for the target genes in human cell lines.
Monoamine oxidase (MAO) inhibitors have been investigated for the treatment of neuropathic pain. Here, we assessed the antiallodynic effects of a novel MAO-B inhibitor, KDS2010, on paclitaxel (PTX)-induced mechanical hypersensitivity. Oral administration of KDS2010 effectively relieved PTX-induced mechanical hypersensitivity in a dose-dependent manner. KDS2010 (25 mg/Kg) significantly prevented and suppressed PTX-induced pain responses with minimal effects on the body weight, motor activity, and working memory. KDS2010 significantly reduced reactive astrocytosis and reactive oxygen species (ROS) level in the L4–L6 spinal cord of PTX-treated mice. Furthermore, KDS2010 reversed the attenuation of GABAergic spontaneous inhibitory postsynaptic current (sIPSC) frequency in spinal dorsal horn neurons, although it failed to restore the reduced tonic GABA A inhibition nor the increased GABA transporter 1 (GAT1) expression in PTX-treated mice. In addition, bath application of a reactive oxygen species (ROS) scavenger (PBN) restored the sIPSC frequency in PTX-treated mice but not in control and PTX + KDS2010-treated mice. These results indicated that the antiallodynic effect of KDS2010 is not due to a MAO-B-dependent GABA production. Finally, PBN alone also exerted a similar analgesic effect as KDS2010, but a co-treatment of PBN with KDS2010 showed no additive effect, suggesting that inhibition of MAO-B-dependent ROS production is responsible for the analgesic effect by KDS2010 on PTX-induced allodynia. Overall, KDS2010 attenuated PTX-induced pain behaviors by restoring the altered ROS level and GABAergic inhibitory signaling in the spinal cord, suggesting that KDS2010 is a promising therapeutic strategy for chemotherapy-induced peripheral neuropathy.
Extracellular matrix (ECM) proteins play a pivotal role in cell growth and differentiation. To characterize aged ECM proteins, we compared the proteomes by shotgun method of young (passage #15) and late senescent (passage #40) human dermal fibroblasts (HDFs) using SDS-PAGE coupled with LC–MS/MS. The relative abundance of identified proteins was determined using mol% of individual proteins as a semi-quantitative index. Fifteen ECM proteins including apolipoprotein B (APOB) and high-temperature requirement factor 1 (HTRA1) were up-regulated, whereas 50 proteins including fibronectin 1 (FN1) and vitronectin (VTN) were down-regulated in late senescent HDFs. The identified ECM proteins combined with plasma membrane were queried to construct the protein–protein interaction network using Ingenuity Pathways Analysis, resulting in a distinct FN1-centered network. Of differentially abundant ECM proteins in shotgun proteomics, the protein levels of FN1, VTN, APOB, and HTRA1 were verified by immunoblot analysis. The results suggest that the aging process in HDFs might be finally involved in the impaired FN1 regulatory ECM network combined with altered interaction of neighboring proteins. Shotgun proteomics of highly aged HDFs provides insight for further studies of late senescence-related alterations in ECM proteins.
In this review, we attempted to summarize and interpret the Phanerozoic geology and mineralization following the article (vol. 71 in Resource Geology) which reviewed the Precambrian geology and mineralization of North Korea. The basement of the Korean peninsula was built during the Precambrian and gradually became more evolved and complex during the Phanerozoic. The northern part of the peninsula was in the active and passive continental margins of the Korea–China platform during the Phanerozoic. In the tectonic environments of the Phanerozoic, the tectonic provinces of North Korea comprise several Paleozoic–Mesozoic intracontinental and rift basins as well as Cenozoic ocean border and rift basins. During the Paleozoic, the sedimentary strata were formed within the marine‐to‐nonmarine intracontinental basins, such as the largest Pyeongnam and Hyesan–Iwon basin, Imjingang rift basin, and several small structural basins, and the sedimentary type of limestone, dolomite, and coal deposits were formed. Mesozoic orogenic events in the peninsula were the most overwhelming geologic event causing block movements through collision and subduction of the paleo‐Pacific plate. Songrim orogeny (late Permian to early Triassic) might be caused by continental collision associated with strong deformation, metamorphism, and granite intrusion. Daebo orogeny (Jurassic) resumed the crustal deformation under a contractional setting during the subduction and caused dextral ductile shearing, magmatism, and metamorphism in the entire peninsula. Amnokgang orogeny, corresponding to Bulguksa orogeny in South Korea, during the Cretaceous formed several pull‐apart or transtensional basins probably because of oblique subduction of the Izanagi plate, and nonmarine sedimentary and pyroclastic sequences were deposited in the basin. The mineralization related to the Mesozoic plutonism was the most dominant in the peninsula. The considerable mineral deposits are ultramafic related magmatic Ni deposits owing to rift magmatism and granite related hydrothermal Au–Ag, Cu, Pb–Zn, Fe, W, and Mo deposits caused by the subduction of paleo‐Pacific plate. During the Tertiary, several structural basins under the extensional regime were overprinted on the Mesozoic basins in the northern part of the peninsula. They contain marine and nonmarine sedimentary rocks and felsic–mafic extrusives. Some sedimentary deposits, such as coal, kaolin, bentonite, diatomite, and zeolite, were formed. The Tertiary Pohang basin in South Korea shows basin geology, magmatism, and mineralization similar to those of North Korea. The Phanerozoic geotectonics of the peninsula are characterized by the evolution of the structural basins and violent magmatism. The peninsula is located on the Amur plate, bounded by the Philippine plate, Pacific plate, and Eurasian plate. Since Phanerozoic, the peninsula's geographic position created an important tectonic link between northeastern China and the Japanese Islands throughout geotectonic evolution. We reviewed the Phanerozoic geology and mineralization following the article (vol. 71 in Resource Geology) which reviewed the Precambrian geology and mineralization of North Korea. The granitoids in the Korean peninsula, the most dominant the Jurassic to the Cretaceous magmatic activities related to the subduction of the paleo‐pacific plate significantly contributed to the formation of the numerous economic hydrothermal Au–Ag, Cu, Pb–Zn, Fe, W, and Mo deposits in the entire peninsula.
Due to the widespread emergence of COVID-19, face masks have become a common tool for reducing transmission risk between people, increasing the need for sterilization methods against mask-contaminated microorganisms. In this study, we measured the efficacy of ultraviolet (UV) laser irradiation (266 nm) as a sterilization technique against Bacillus atrophaeus spores and Escherichia coli on three different types of face mask. The UV laser source demonstrated high penetration of inner mask layers, inactivating microorganisms in a short time while maintaining the particle filtration efficiency of the masks. This study demonstrates that UV laser irradiation is an efficient sterilization method for removing pathogens from face masks.
Light-responsive soft actuators have recently drawn attention as the need for lightweight remotely controlled actuator systems with high environmental adaptability and safe human–robot interaction interface characteristics has increased. In this study, we focused on a near-infrared (NIR) light-tunable hydrogel soft actuator system capable of fast and precisely controllable mechanical actuation even under the irradiation of NIR light with low intensity. We designed a bilayer type hydrogel soft actuator consisting of a poly(N-isopropylacrylamide) (PNIPAAm) active layer containing gold nanorods (AuNRs) as a photothermal agent and poly(acrylamide) (PAAm) passive layer. AuNRs with an aspect ratio of 4.12 showed the largest longitudinal plasmon resonance absorption peak in the NIR 880 nm range, which was used as a photothermal agent. The AuNR-incorporated PNIPAAm/PAAm hydrogel with a bilayer structure (PNIPAAm-AuNR/PAAm) exhibited more than 70% gel fraction and temperature-sensitive swelling behaviors. In particular, rod-shaped PNIPAAm-AuNR/PAAm hydrogels showed rapid bending deformation by a photothermally induced phase transition of PNIPAAm upon 880 nm laser irradiation, but a PNIPAAm/PAAm bilayer hydrogel without AuNRs did not show a light-induced bending movement. The NIR-responsive bending actuation of the hydrogel can be precisely controlled by cross-linking density, content of photothermal agent, NIR laser intensity, and thickness ratio of the active/passive layer. It was observed that the full bending deformations of the hydrogel into a ring shape through an arc occurred within a minute under NIR irradiation with a lower intensity of less than 1.0 W/cm². Hydrogels showed a cell viability of more than 95% in the biocompatibility test, indicating no significant cytotoxicity. Therefore, these PNIPAAm-AuNR/PAAm hydrogels are promising soft actuator materials that can be controlled by low-intensity NIR irradiation for remotely controlled human–robot interaction interface applications.
Photodynamic therapy (PDT) is a promising cancer treatment with fewer side effects, and it eliminates tumors in target tissues with reactive oxygen species produced by photosensitizers (PS) and light. In this study, we isolated methyl pheophorbide A, which induces photodynamic cell death in the U937 and SK-HEP-1 cells, from perilla leaves. Its potential as a material for the development of a new PS was also evaluated. The methyl pheophorbide A is a dark green porphyrin compound isolated from methanol extract of perilla leaves. Apoptosis occurred was methyl pheophorbide A treated and irradiated with light, and there was no significant change where light not treated. In both U937 and SK-HEP-1 cells, apoptotic body, vesicle formation, and DNA ladder were confirmed in the light-irradiated. The caspase-3/7 activity an important factor in apoptosis, was 101.50 ± 14.24% when treated with 0.25 μg/ml methyl pheophorbide A in U937, and 91.32 ± 16.23% when treated with 1.00 μg/ml in SK-HEP-1 cells. The apoptotic phenomenon appeared more strongly when the methyl pheophorbide A concentration was increased with irradiating light. This study demonstrates the isolation, identification, and phototoxic activity of methyl pheophorbide A in perilla leaves. We expect that this study will be useful in the search for PS candidates using natural products.
This study investigates the gas tungsten arc weldability of the high-entropy alloy CoCrFeMnNi using CoCrFeMnNi and CuCrFeMnNi fillers. The CoCrFeMnNi-based weld had the same face-centered cubic (FCC) structure as the base metal, and the CuCrFeMnNi-based weld exhibited phase separation of the Cu-rich phase in addition to the FCC structure. Although the grain size of the CuCrFMnNi-based weld was similar to that of the CoCrFeMnNi-based weld, the Cu-rich phase formed in the CuCrFMnNi-based weld enhanced its tensile properties. This occurred because the dislocation movement and slip band in the weld metal were hindered by the formation of the Cu-rich phase.
Petroleum residue oil-based mesophase pitch production suffers from its low yield of mesophase. There have been continuous efforts, such as catalyst-assisted reactions and multistep heat treatments, to produce high-purity mesophase pitch. However, most of these techniques have difficulties with the processability. In this study, we suggest a novel fluorine pretreatment of fluid catalytic cracking (FCC) decant oil for mesophase pitch (MP) production. The effects of fluorine pretreatment on FCC decant oil were evaluated with mass spectrometry (MS) and their hydrogen donating ability. Subsequently, the MPs from pristine pitches with fluorine pretreatment were intensively compared in terms of structural, thermal, and chemical characteristics. From these results, it was found that fluorine pretreatment helps mesophase formation by catalytic radical polymerization but does not cause coking and does not require posttreatment. It was found that the fluorination method can also provide an effective method for generating MP by increasing the hydrogen donating ability (HDA) fraction. We believe that the results of this work could inspire new insights into MP production.
This study presents a Ku‐band ×3 frequency multiplier implemented using the 65 nm CMOS process. A frequency tripler core consisting of a single‐ended structure is employed to achieve a small size. A high‐pass filter and a notch filter are used in the output matching network to overcome the low harmonic suppression of the single‐ended structure. Furthermore, an input variable gain amplifier, a frequency tripler core, and an output variable gain amplifier are used in the ×3 frequency multiplier structure to achieve high conversion gain and harmonic suppression. The size of the ×3 frequency multiplier is 0.8 × 0.9 mm². Measurement results show that the conversion gain for the 15.99–17.52 GHz range is 1.53–24.81 dB at input power values of –20, –25, and –30 dBm, and the harmonic suppression is greater than 24.29–34.71 dBc. In the operating frequency band, the input and output return losses are greater than 10 dB, and the power consumption is 15–18 mW.
In chronic myelogenous leukemia (CML), treatment-free remission (TFR) is defined as maintaining a major molecular response (MMR) without a tyrosine kinase inhibitor (TKI), such as imatinib (IM). Several studies have investigated the safety of the first TFR (TFR1) attempt and suggested recommendation guidelines for such an attempt. However, the plausibility and predictive factors for a second TFR (TFR2) have yet to be reported. The present study included 21 patients in chronic myeloid leukemia who participated in twice repeated treatment stop attempts. We develop a mathematical model to analyze and explain the outcomes of TFR2. Our mathematical model framework can explain patient-specific molecular response dynamics. Fitting the model to longitudinal BCR-ABL1 transcripts from the patients generated patient-specific parameters. Binary tree decision analyses of the model parameters suggested a model based predictive binary classification factor that separated patients into low- and high-risk groups of TFR2 attempts with an overall accuracy of 76.2% (sensitivity of 81.1% and specificity of 69.9%). The low-risk group maintained a median TFR2 of 28.2 months, while the high-risk group relapsed at a median time of 3.25 months. Further, our model predicted a patient-specific optimal IM treatment duration before the second IM stop that could achieve the desired TFR2 (e.g., 5 years).
This study was designed to investigate the effects of polymorphisms in RETN on remission in RA patients receiving TNF-α inhibitors. In addition, machine learning algorithms were trained to predict remission. Ten single-nucleotide polymorphisms were investigated. Univariate and multivariable analyses were performed to evaluate associations between genetic polymorphisms and the efficacy of TNF-α inhibitors. A random forest–based classification approach was used to assess the importance of different variables associated with the efficacy of TNF-α inhibitors. Various machine learning methods were used for finding vital factors and prediction of remission. The eight most significant features included in the multivariable analysis were sex, age, hypertension, sulfasalazine, rs1862513, rs3219178, rs3219177, and rs3745369. T-allele carriers of rs3219177 and males showed approximately 6.0- and 3.6-fold higher remission rates compared to those with the CC genotype and females, respectively. The elastic net algorithm was the best machine-learning method for predicting remission of patients with RA treated with TNF-α inhibitors. On the basis of the results of this study, it may be possible to design individually tailored treatment regimens to predict the efficacy of TNF-α inhibitors.
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2,723 members
Byeong Hwa Jeon
  • College of Medicine
Ramaraj Sathasivam
  • Department of Crop Science
Ananda Rao Boddu
  • Dept. of Advanced Organic Materials and Textile System Engineering.
Sajith Dananjaya
  • College of Veterinary Medicine
Ajit Phule
  • Department of Environmental Engineering
6 Munhwa-Dong, Jung-Gu, 301-747, Daejeon, South Korea
Head of institution
Prof. Jongsun Park