Konkuk University
  • Seoul, Chungcheongbuk-do, South Korea
Recent publications
Wastewater containing an azo dye Orange G (OG) causes massive environmental pollution, thus it is critical to develop a highly effective, environmental-friendly, and reusable catalyst in peroxymonosulfate (PMS) activation for OG degradation. In this work, we successfully applied a magnetic MnFe2O4/α-MnO2 hybrid fabricated by a simple hydrothermal method for OG removal in water. The characteristics of the hybrid were investigated by X-ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller method, vibrating sample magnetometry, electron paramagnetic resonance, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The effects of operational parameters (i.e., catalytic system, catalytic dose, solution pH, and temperature) were investigated. The results exhibited that 96.8% of OG degradation was obtained with MnFe2O4/α-MnO2(1:9)/PMS system in 30 min regardless of solution pH changes. Furthermore, the possible reaction mechanism of the coupling system was proposed, and the degradation intermediates of OG were identified by mass spectroscopy. The radical quenching experiments and EPR tests demonstrated that SO4• ̶, O2• ̶, and ¹O2 were the primary reactive oxygen species responsible for the OG degradation. The hybrid also displayed unusual stability with less than 30% loss in the OG removal after four sequential cycles. Overall, magnetic MnFe2O4/α-MnO2 hybrid could be used as a high potential activator of PMS to remove orange G and maybe other dyes from wastewater.
Petroleum industries are large water consumers and generate a lot of wastewater at various stages of industrial operations. Wastewater from the petroleum industries contain recalcitrant pollutants such as hydrocarbons that are present in high concentrations, dissolved solids and sulfur compounds that can pose potential environmental threat. Bioelectrochemical systems (BESs) are known to be sustainable processes to treat the various kinds of wastewaters such as petroleum wastewater, while simultaneously generating the bioelectricity and value-added chemicals. This review focuses on various applications of BESs such as microbial fuel cells (MFC), microbial electrolysis cells (MEC), and microbial desalination cells (MDC) using diverse types of wastewaters (petroleum sludge, produced water, formation water, and petroleum refinery wastewater) from the petroleum industries. Overall, a hybrid type BES with hydrocarbon wastewater achieved a 98% of columbic efficiency, 96.5% of chemical oxygen demand (COD), 99% of phenanthrene, 94% of pyrene and 80% of TDS removal which are superior to single and dual chamber BES performances. The review also compares the existing biological processes with BESs in terms of the treatment of hydrocarbons and process sustainability. Treatment efficiency of petroleum wastes via the BES can be further improved by integrating the biological and electrochemical processes to develop a sustainable approach to bio-refinery route.
This work reports the antibacterial application of the dual oxidation state of nickel on g-C3N4 (dos-Nickel/g-C3N4) nanocomposite. The nanocomposite is prepared through simple wet impregnation assisted pyrolysis technique, and is characterized by standard techniques. Different geometries of nickel (spherical, and hexagonal disc) are decorated on the graphitic-carbon nitride surface examined through HR-TEM imagery. Photoluminescence of the synthesized nanocomposite can achieve better charge separation due to the quenching effect. The photocatalytic disinfection of dos-Ni/g-C3N4 nanocomposite is evaluated using E. coli as a model pathogen under normal indoor daylight. Selective dosage of nickel in the nanocomposite showed 100 % photocatalytic destruction efficiency of E. coli compared to g–C3N4, under shorter irradiation time. The photocatalytic disinfection mechanism is interrogated with various scavengers, and it is determined that superoxide (·O2–), and hole (h⁺) are the crucial radicals participating in the disinfection destructive mechanism. Taken together, this research presents the fabrication of dos-Ni/g-C3N4 nanocomposite, and its potential application to bioenvironmental remediation under normal indoor daylight conditions.
Context: Cordycepin (COR), from Cordyceps militaris L., (Cordycipitaceae), is a valuable agent with immense health benefits. Objective: The protective effects of COR in ageing-associated oxidative and apoptosis events in vivo and hydrogen peroxide (H2O2)-exposed spermatogenesis gene alterations in TM3 Leydig cells was investigated. Materials and methods: Male Sprague-Dawley rats were divided into young control (YC), aged control (AC) and COR treated (COR-20) aged groups. COR-20 group received daily doses of COR (20 mg/kg) for 6 months. Cell viability and hormone levels were analysed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and enzyme immunoassay kits with COR treated at 1, 5, and 10 μg/mL. Oxidative enzymes, spermatogenic, and apoptotic expression in testis tissues were evaluated by Western blotting and real-time RT-PCR. Results: COR treatment (1, 5, and 10 μg/mL) significantly (p < 0.05 ∼ p < 0.001) inhibited the H2O2-induced decrease in the percentage of viable cells (from 63.27% to 71.25%, 85.67% and 93.97%, respectively), and reduced the malondialdehyde (MDA) content (from 4.28 to 3.98, 3.14 and 1.78 nM MDA/mg protein, respectively). Further, the decreased antioxidant enzymes (glutathione-S-transferase mu5, glutathione peroxidase 4 and peroxiredoxin 3), spermatogenesis-related factors (nectin-2 and inhibin-α) and testosterone levels in H2O2-exposed TM3 cells were significantly (p < 0.05 ∼ p < 0.001) ameliorated by COR. In aged rats, COR (20 mg/kg) restored the altered enzymatic and non-enzymatic antioxidative status and attenuated the apoptotic p53 and Bax/Bcl-2 expression significantly (p < 0.05). Conclusion: COR might be developed as a potential agent against ageing-associated and oxidative stress-induced male infertility. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Breast cancer is an expanding threat that leads to many women's death worldwide. Despite the improvement of the early detection methods and treatment, still, there is a high number of breast cancer mortality. To increase patient survival in breast cancer, identifying novel biomarkers is essential for therapeutics targets. The Glycophorin C (GYPC) gene is correlated with patient survival, which can be a possible biomarker for early detection in breast cancer progression. However, the expression of GYPC is not clearly defined in breast cancer. Here, we widely analyzed the expression pattern of GYPC in breast cancer and patient survival datasets through several bioinformatics tools. GYPC mRNA expression using ONCOMINE, GENT2, and GTX2 webs. Also, The co-expression profile of GYPC has been repossessed from Ma breast four datasets from Oncomine dataset. Our study revealed that mRNA expression of GYPC is strongly correlated with the survival of breast cancer patients, suggesting its role as a tumor suppressor. The downregulation of GYPC in breast cancer tissue is examined by promoter methylation and copy number alterations. The downregulation of GYPC expression was significantly correlated with high patient survival. Moreover, we performed pathway analysis via Enricher and gene ontology web using 20 positively correlated genes. Consequently, our analyzed data suggested that GYPC might be an essential therapeutics and prognostic biomarker in breast cancer.
To survive in diverse environments, bacteria adapt by changing the composition of their cell membrane fatty acids. Compared with aerobic bacteria, Cutibacterium acnes has much greater contents of branched-chain fatty acids (BCFAs) in the cell membrane, which helps it survive in anaerobic environments. To synthesize BCFAs, C. acnes acyl carrier protein (CaACP) has to transfer growing branched acyl intermediates from its hydrophobic cavity to fatty acid synthases. CaACP contains an unconserved, distinctive Cys50 in its hydrophobic pocket, which corresponds to Leu in other bacterial acyl carrier proteins (ACPs). Herein, we investigated the substrate specificity of CaACP and the importance of Cys50 in its structural stability. We mutated Cys50 to Leu (C50L mutant) and measured the melting temperatures (Tms) of both CaACP and the C50L mutant by performing circular dichroism experiments. The Tm of CaACP was very low (49.6 °C), whereas that of C50L mutant was 55.5 °C. Hydrogen/deuterium exchange experiments revealed that wild-type CaACP showed extremely fast exchange rates within 50 min, whereas amide peaks of the C50L mutant in the heteronuclear single quantum coherence spectrum remained up to 200 min, thereby implying that Cys50 is the key residue contributing to the structural stability of CaACP. We also monitored chemical shift perturbations upon apo to holo, apo to butyryl, and apo to isobutyryl conversion, confirming that CaACP can accommodate isobutyryl BCFAs. These results provide a preliminary understanding into the substrate specificity of CaACPs for the production of BCFAs necessary to maintain cell membrane fluidity under anaerobic environments.
To diagnose autism spectrum disorder (ASD), researchers have sought biomarkers whose alterations correlate with the susceptibility to ASD. However, biomarkers closely related to the pathophysiology of ASD are lacking. Even though excitation/inhibition (E/I) imbalance has been suggested as an underlying mechanism of ASD, few studies have investigated the actual ratio of glutamate (Glu) to γ-aminobutyric acid (GABA) concentration in vivo. Moreover, there are controversies in the directions of E/I ratio alterations even in extensively studied ASD animal models. Here, using proton magnetic resonance spectroscopy ( ¹ H-MRS) at 9.4T, we found significant differences in the levels of different metabolites or their ratios in the prefrontal cortex and hippocampus of Cntnap2 −/− mice compared to their wild-type littermates. The Glu/GABA ratio, N-acetylaspartate (NAA)/total creatine (tCr) ratio, and tCr level in the prefrontal cortex were significantly different in Cntnap2 −/− mice compared to those in wild-type mice, and they significantly correlated with the sociability of mice. Moreover, receiver operating characteristic (ROC) analyses indicated high specificity and selectivity of these metabolites in discriminating genotypes. These results suggest that the lowered Glu/GABA ratio in the prefrontal cortex along with the changes in the other metabolites might contribute to the social behavior deficit in Cntnap2 −/− mice. Our results also demonstrate the utility of ¹ H-MRS in investigating the underlying mechanisms or the diagnosis of ASD.
Alzheimer’s disease (AD) is one of the progressive neurodegenerative diseases characterized by β-amyloid (Aβ) production and Phosphorylated-Tau (p-Tau) protein in the cerebral cortex. The precise mechanisms of the cause, responsible for disease pathology and progression, are not well understood because there are multiple risk factors associated with the disease. Viral infection is one of the risk factors for AD, and we demonstrated that Zika virus (ZIKV) infection in brain organoids could trigger AD pathological features, including Aβ and p-Tau expression. AD-related phenotypes in brain organoids were upregulated via endoplasmic reticulum (ER) stress and unfolded protein response (UPR) after ZIKV infection in brain organoids. Under persistent ER stress, activated-double stranded RNA-dependent protein kinase-like ER-resident (PERK) triggered the phosphorylation of Eukaryotic initiation factor 2 (eIF2α) and then BACE, and GSK3α/β related to AD. Furthermore, we demonstrated that pharmacological inhibitors of PERK attenuated Aβ and p-Tau in brain organoids after ZIKV infection.
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.
Background As the number of large-scale studies involving multiple organizations producing data has steadily increased, an integrated system for a common interoperable format is needed. In response to the coronavirus disease 2019 (COVID-19) pandemic, a number of global efforts are underway to develop vaccines and therapeutics. We are therefore observing an explosion in the proliferation of COVID-19 data, and interoperability is highly requested in multiple institutions participating simultaneously in COVID-19 pandemic research. Results In this study, a laboratory information management system (LIMS) approach has been adopted to systemically manage various COVID-19 non-clinical trial data, including mortality, clinical signs, body weight, body temperature, organ weights, viral titer (viral replication and viral RNA), and multiorgan histopathology, from multiple institutions based on a web interface. The main aim of the implemented system is to integrate, standardize, and organize data collected from laboratories in multiple institutes for COVID-19 non-clinical efficacy testings. Six animal biosafety level 3 institutions proved the feasibility of our system. Substantial benefits were shown by maximizing collaborative high-quality non-clinical research. Conclusions This LIMS platform can be used for future outbreaks, leading to accelerated medical product development through the systematic management of extensive data from non-clinical animal studies.
Non-alcoholic fatty liver disease (NAFLD) is a metabolic disease characterized by multiple pathologies. The progression of dementia with NAFLD may be affected by various risk factors, including brain insulin resistance, cerebrovascular dysfunction, gut dysbiosis, and neuroinflammation. Many recent studies have focused on the increasing prevalence of dementia in patients with NAFLD. Dementia is characterized by cognitive and memory deficits and has diverse subtypes, including vascular dementia, Alzheimer’s dementia, and diabetes mellitus-induced dementia. Considering the common pathological features of NAFLD and dementia, further studies on the association between them are needed to find appropriate therapeutic solutions for diseases. This review summarizes the common pathological characteristics and mechanisms of NAFLD and dementia. Additionally, it describes recent evidence on association between NAFLD and dementia progression and provides novel perspectives with regard to the treatment of patients with dementia secondary to NAFLD.
Ni-rich cathode materials have promising applications in lithium-ion batteries owing to their high energy density and reasonable cost. The surface stabilization of these materials is vital for achieving excellent electrochemical performance. In this study, a fast ionic conductor, Li6.25La3Zr2Al0.25O12 (LLZAO), was successfully coated on the surface of LiNi0.88Co0.05Mn0.07O2 (LNCM) using a polydopamine (PDA) modification method. The abundant catechol groups of the intermediate PDA layer on the Ni0.88Co0.05Mn0.07(OH)2 (NCM(OH)2) precursor attracted metal ions in an aqueous solution, and a uniform LLZAO coating layer was formed after calcination under an O2 flow. The presence of the LLZAO protective film on the surface of LNCM was confirmed using several characterization techniques. The LLZAO-coated LNCM exhibited superior electrochemical properties compared to those of the pristine LNCM. Moreover, the LLZAO-coated LNCM demonstrated excellent electrochemical stability even at a high temperature (60 ℃). The deterioration of the surface structure of LNCM was significantly suppressed by the formation of the LLZAO coating layer, and LLZAO improved the Li⁺ ion transport at the electrode/electrolyte interface.
Increasing popular interest in health and hygiene has amplified the demand for natural plant-based extracts in textile applications. To enable functionalization, aqueous extracts of natural plant parts, specifically onion peel, turmeric root, and pomegranate rind in combination, were applied to cotton fabric by exhaustion, and their antimicrobial activity, UV blocking properties, antioxidant activity, and color properties were investigated. UV–visible spectroscopy was performed to confirm the presence of polyphenolic compounds, such as flavonoids, curcumin, and tannins in onion peel, turmeric root, and pomegranate rind extracts, respectively. The functional properties of the extracts differed owing to their different chemical structures and bioactivities. A synergistic effect of the pomegranate rind extract with onion peel and turmeric root on antimicrobial activity, antioxidant activity, and UV protection performance was observed. The relatively poor color properties of the pomegranate rind and onion peel extracts were considerably enhanced by the addition of turmeric root extract primarily containing an intense yellow colorant, curcumin. All treated fabrics had yellow hues, and their color fastness ranged from moderate to excellent. The aqueous natural plant extract combinations of onion peel, turmeric root, and pomegranate rind could be an innovative approach to improve dyeing and functional properties in sustainable textile applications.
Aqueous zinc-ion batteries (ZIBs) are receiving considerable research highlights owing to their high safety and environment-friendliness. To implement this promising technology for grid-scale energy storage, effective cathode materials with high capacity, cycle stability, and electrochemical kinetics should be developed. Herein, the synthesis of uniquely structured porous VN-reduced graphene oxide composite (VN-rGO) microspheres through a facile spray pyrolysis process and their application as cathodes for ZIBs are introduced. The electrochemical reaction mechanism of VN-rGO microspheres with zinc ions is investigated through various in situ and ex situ analyses. During the initial charge process, VN phase transforms into the Zn3(OH)2V2O7·2H2O (ZVOH) phase. From the second cycle and on, the ZVOH phase undergoes zinc-ion ingress and egress processes. VN-rGO microspheres exhibit an unprecedented high capacity (809 mA h g⁻¹ at 0.1 A g⁻¹), high energy density (613 W h kg⁻¹), and good rate capability (467 mA h g⁻¹ at 2.0 A g⁻¹). The cathode delivers a reversible capacity of 445 mA h g⁻¹ after 400 cycles at 1.0 A g⁻¹, which ascertains the robustness of the structure. The 3D porous rGO matrix to which VN nanocrystals are homogenously anchored accelerates the zinc-ion storage kinetics and endows the cathode with structural robustness.
To meet strong emission regulations such as Euro-7, which is expected to be implemented in 2025. The multiple-injection strategy is one of well-known solutions to reduce exhaust gas and improve combustion performance on GDI engine. In order to realize multiple-injection strategy, it is necessary to secure excellent flow rate repeatability within short period. Therefore, the purpose of this study was to analyze the flow rate repeatability of GDI injector under various multiple injection conditions and to correlate with needle behavior of GDI injector and flow rate repeatability. To analyze flow rate repeatability, the injection rate data was obtained by the Bosch method and the individual flow rates of 110 shots were analyzed under several experimental conditions. The movements of the ball and armature inside the injector were visualized using the X-ray phase contrast imaging (XPCI) technique, and the individual behaviors of the ball and the armature were quantitatively analyzed by image post-processing analysis. In this study were used two test GDI injectors with same structure. Whereas Flow rate results were different on shorter dwell time conditions. This study revealed that a specific injector had unstable injection rate and worse Shot to Shot (STS) deviation under dwell time 0.7 ms. In addition, armature bouncing appeared in a specific GDI injector. This armature bouncing affects unstable flow rate characteristics because when armature lift up again, the position of armature was different at every time.
H2/CO2 separation is essential for various industrial applications, such as hydrocarbon steam reforming for H2 production. Herein, a layered composite membrane composed of nanoporous graphene (NG) and polyethylene oxide (PEO) is developed. The membrane demonstrates an ultrafast H2 permeability of ca. 32 240 barrer with a moderate H2/CO2 selectivity of 25, which far surpasses the upper bound of the separation performance demonstrated by existing membrane materials. The regularly layered structure is fabricated by facilitating the intercalation of PEO via an aqueous graphene-oxide liquid crystal (GOLC) scaffold. After preparing the layered GO/PEO membrane, hot pressing is conducted to activate dense nanopores on the basal plane of graphene, resulting in an NG/PEO membrane. The permeation of gas molecules is significantly enhanced owing to the presence of nanopores and expansion of the interlayer spacing by PEO. In contrast, CO2 permeation is lower than that of H2 owing to its strong binding interaction with PEO, and molecular simulations demonstrate that this CO2–PEO interaction is significantly enhanced owing to the confinement of PEO in the graphene interlayer spacing, particularly at d-spacing of approximately 7–8 Å.
Considerable seawater bittern is produced during salt production. Seawater bittern can be used to reduce CO2 and SOx because of the presence of valuable mineral ions, such as K⁺ and Mg²⁺, which react with the carbonate and sulfate ions present in high concentrations. In this study, a novel seawater bittern recovery process is proposed for CO2 and SOx utilization. The proposed process has the following steps: (1) metal ion separation of the seawater bittern to produce KOH and Mg(OH)2; (2) SOx capture and utilization using the generated Mg(OH)2; (3) CO2 capture and utilization using the generated KOH. The pay-back period (PBP) was calculated to verify the economic feasibility of the proposed process. The results revealed an SOx and a CO2 capture efficiency of approximately 99 % and 98 %, respectively. Furthermore, the annual net revenue was approximately 153,439 USD/y based on the profit obtained from the generated product and savings on absorbent. Thus, the PBP was approximately 6.2 y.
The damaged concrete columns under earthquake can be retrofitted with fiber-reinforced polymer (FRP) and the axial mechanical properties of the strengthened columns can be greatly enhanced. In the present study, monotonic and repeated axial compressive behavior of damaged concrete prisms repaired by basalt FRP (BFRP) was investigated. Pre-damage tests were performed on plain concrete prismatic specimens under three axial compressive loading levels. Then, the damaged specimens were repaired with 1-, 2-, 4-, and 6-layer BFRP composites, followed by monotonic or repeated compression tests. The test results showed that the compressive strength and axial deformation capacities of the damaged prismatic specimens under monotonic compressive loading were improved remarkably after repairing. However, in the stress–strain curves of BFRP-repaired specimens, the initial elastic modulus, and the strength at the turning and ultimate states decreased with the increase of initial damage. Based on the test results of this study and existing literature, the strength and strain at the turning and ultimate states were estimated, and a monotonic stress–strain relationship was proposed for BFRP-repaired concrete prisms considering the adverse effect of pre-damage level. Further, a modified repeated compressive stress–strain model was proposed for BFRP-repaired damaged concrete prisms. The proposed models predicted well the test results.
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3,076 members
Hyoung-Moon Kim
  • Department of Applied Statistics
Pavithra K Balasubramanian
  • College of Sciences
Ahmed Abdal Dayem
  • Department of Animal Biotechnology
Xuan-Hung Pham
  • Department of Bioscience and Technology
M Nisar
  • Department of Biological Engineering
268 chungwondaero, 380-701, Seoul, Chungcheongbuk-do, South Korea