Publications by authors named "Young-Min Kim"

601 Publications

Reply to the letter by Junjie Jiang et al. regarding our manuscript "Association between triglyceride-glucose index and gastric carcinogenesis: a health checkup cohort study".

Gastric Cancer 2021 Sep 4. Epub 2021 Sep 4.

Division of Endocrinology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 06273, Korea.

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http://dx.doi.org/10.1007/s10120-021-01245-xDOI Listing
September 2021

Beneficial effect on rapid skin wound healing through carboxylic acid-treated chicken eggshell membrane.

Mater Sci Eng C Mater Biol Appl 2021 Sep 30;128:112350. Epub 2021 Jul 30.

Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea. Electronic address:

At the initial stage of wound healing, growth factors stimulate tissue regeneration by interacting with the extracellular matrix (ECM), leading to rapid wound repair and structural support. Chicken eggshell membrane (ESM) is a low-cost and highly functional ECM biomaterial for tissue regeneration. However, natural ESM has limitations for tissue engineering purposes because it is difficult to control the size, shape, and biocompatibility of the surfaces. To overcome this, blends of synthetic materials and natural ESMs, such as soluble eggshell membrane protein, are combined for biomaterial applications. Unfortunately, it is difficult to pattern fibrous structure. Here, we modified the natural chicken ESM through weak acid treatment to promote wound healing and skin regeneration without loss of fibrous structure. Treatment of citric acid and acetic acid reacted the amine or amide group with carboxyl groups (R-COOH) and achieved hydrophilicity for adherence of proliferating regenerative cells. Our in vitro study revealed that the modified ESM scaffolds significantly promoted human dermal fibroblasts adhesion, viability, proliferation, and cytokine secretion, compared with natural ESM. In addition, the modified ESM accelerated skin regeneration and enhanced the wound healing process even at early stages in an in vivo rat wound model. Collectively, the modified ESM performed best for promoting skin regeneration, cytokine secretion, epidermal cell proliferation, and controlling the inflammatory response both in vitro and in vivo.
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http://dx.doi.org/10.1016/j.msec.2021.112350DOI Listing
September 2021

Injectable polymeric nanoparticle hydrogel system for long-term anti-inflammatory effect to treat osteoarthritis.

Bioact Mater 2022 Jan 7;7:14-25. Epub 2021 Jul 7.

Center for Biomaterials, Korea Institute of Science & Technology, Seoul, 02792, South Korea.

Treatment of osteoarthritis (OA) by administration of corticosteroids is a commonly used method in clinics using anti-inflammatory medicine. Oral administration or intra-articular injection of corticosteroids can reduce the pain and progress of cartilage degeneration, but they are usually insufficient to show local and long-term anti-inflammatory effects because of their fast clearance in the body. In this study, we suggest an injectable anti-OA drug depot system for sustained drug release that provides long-term effective therapeutic advantages. Amphiphilic poly(organophosphazene), which has temperature-dependent nanoparticle forming and sol-gel transition behaviors when dissolved in aqueous solution, was synthesized for triamcinolone acetonide (TCA) delivery. Because hydrophobic parts of the polymer can interact with hydrophobic parts of the TCA, the TCA was encapsulated into the self-assembled polymeric nanoparticles. The TCA-encapsulated polymeric nanoparticles (TePNs) were well dispersed in an aqueous solution below room temperature so that they can be easily injected as a sol state into an intra-articular region. However, the TePNs solution transforms immediately to a viscose 3D hydrogel like a synovial fluid in the intra-articular region via the conducted body temperature. An TCA release study showed sustained TCA release for six weeks. One-time injection of the TePN hydrogel system in an early stage of OA-induced rat model showed a great inhibition effect against further OA progression. The OA-induced knees completely recovered as a healthy cartilage without any abnormal symptoms.
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http://dx.doi.org/10.1016/j.bioactmat.2021.05.028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8377411PMC
January 2022

Correction to: Association between triglyceride-glucose index and gastric carcinogenesis: a health checkup cohort study.

Gastric Cancer 2021 Aug 31. Epub 2021 Aug 31.

Division of Gastroenterology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 06273, Korea.

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http://dx.doi.org/10.1007/s10120-021-01240-2DOI Listing
August 2021

DMRT1 gene disruption alone induces incomplete gonad feminization in chicken.

FASEB J 2021 Sep;35(9):e21876

Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Korea.

Compared with the well-described XY sex determination system in mammals, the avian ZW sex determination system is poorly understood. Knockdown and overexpression studies identified doublesex and mab-3-related transcription factor 1 (DMRT1) as the testis-determining gene in chicken. However, the detailed effects of DMRT1 gene disruption from embryonic to adult development are not clear. Herein, we have generated DMRT1-disrupted chickens using the clustered regularly interspaced short palindromic repeats-associated protein 9 system, followed by an analysis of physiological, hormonal, and molecular changes in the genome-modified chickens. In the early stages of male chicken development, disruption of DMRT1 induced gonad feminization with extensive physiological and molecular changes; however, functional feminine reproductivity could not be implemented with disturbed hormone synthesis. Subsequent RNA-sequencing analysis of the DMRT1-disrupted chicken gonads revealed gene networks, including several novel genes linearly and non-linearly associated with DMRT1, which are involved in gonad feminization. By comparing the gonads of wild type with the genome-modified chickens, a set of genes were identified that is involved in the ZW sex determination system independent of DMRT1. Our results extend beyond the Z-dosage hypothesis to provide further information about the avian ZW sex determination system and epigenetic effects of gonad feminization.
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http://dx.doi.org/10.1096/fj.202100902RDOI Listing
September 2021

Cellulose nanocrystals as support nanomaterials for dual droplet-based freeform 3D printing.

Carbohydr Polym 2021 Nov 22;272:118469. Epub 2021 Jul 22.

Graduate Program in Biomaterials Science & Engineering, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea; Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, South Korea. Electronic address:

The selection of sacrificial support materials is important in the fabrication of complex freeform structures. In this study, a dual droplet-based, freeform 3D printing method for pseudoplastic alginate biomaterial inks was developed using Bingham plastic cellulose nanocrystals (CNCs) as support nanomaterials. CNCs-CaCl mixture compositions and alginate concentrations were varied to enhance printability with rheological properties of shape fidelity and structural stability. The mixtures supported the shape of alginate and allowed CaCl diffusion-based cross-linking during 3D printing. The hydrogels showed rheological and physicochemical properties similar to those of pure alginate hydrogel, as CNCs were removed during post-printing processing. BSA-loaded multi-layered spheres, freeform 3D-printed for oral protein drug delivery, protected BSA in the gastric environment and provided controlled and sustained release of BSA into the intestinal environment as layer width and alginate concentration increased. This method can facilitate freeform 3D printing of diverse pseudoplastic biomaterial inks for biomedical applications.
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http://dx.doi.org/10.1016/j.carbpol.2021.118469DOI Listing
November 2021

Regulating Te Vacancies through Dopant Balancing via Excess Ag Enables Rebounding Power Factor and High Thermoelectric Performance in p-Type PbTe.

Adv Sci (Weinh) 2021 Aug 13:e2100895. Epub 2021 Aug 13.

Department of Materials Science and Engineering, Hanbat National University, Daejeon, 34158, Republic of Korea.

Thermoelectric properties are frequently manipulated by introducing point defects into a matrix. However, these properties often change in unfavorable directions owing to the spontaneous formation of vacancies at high temperatures. Although it is crucial to maintain high thermoelectric performance over a broad temperature range, the suppression of vacancies is challenging since their formation is thermodynamically preferred. In this study, using PbTe as a model system, it is demonstrated that a high thermoelectric dimensionless figure of merit, zT ≈ 2.1 at 723 K, can be achieved by suppressing the vacancy formation via dopant balancing. Hole-killer Te vacancies are suppressed by Ag doping because of the increased electron chemical potential. As a result, the re-dissolution of Na Te above 623 K can significantly increase the hole concentration and suppress the drop in the power factor. Furthermore, point defect scattering in material systems significantly reduces lattice thermal conductivity. The synergy between defect and carrier engineering offers a pathway for achieving a high thermoelectric performance by alleviating the power factor drop and can be utilized to enhance thermoelectric properties of thermoelectric materials.
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http://dx.doi.org/10.1002/advs.202100895DOI Listing
August 2021

Association between triglyceride-glucose index and gastric carcinogenesis: a health checkup cohort study.

Gastric Cancer 2021 Aug 5. Epub 2021 Aug 5.

Division of Gastroenterology, Department of Internal Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonjuro, Gangnam-gu, Seoul, 06273, Korea.

Background: We aimed to investigate the association between the triglyceride-glucose (TyG) index and gastric carcinogenesis, including precancerous conditions such as dysplasia, atrophic gastritis, and intestinal metaplasia.

Methods: Patients who received an upper endoscopic assessment at a medical center were included. The enrolled patients were divided into four categories according to their TyG index quartile (Q). To evaluate the relationship between increase of TyG index and gastric cancer, we analyzed the patients who received a health checkup twice. Moreover, receiver-operating characteristic curve analysis was used to establish cut-off value of the TyG index for gastric cancer.

Results: Of 127,564 enrolled patients, 43,525 (34.1%) and 186 (0.1%) were diagnosed with precancerous conditions and gastric cancer, respectively. The odds ratios (ORs) of precancerous conditions given TyG index progressively increased across quartiles: using Q1 as the reference: Q2 (OR = 1.403, P < 0.001), Q3 (OR = 1.646, P < 0.001), and Q4 (OR = 1.656, P < 0.001). The ORs of gastric cancer also increased according to the quartiles: Q2 (OR = 1.619, P = 0.045), Q3 (OR = 2.180, P = 0.004), and Q4 (OR = 2.363, P = 0.001). Moreover, the increase in TyG index between baseline and follow-up tests was more significant in gastric cancer group than in control group (P = 0.001). The optimal cut-off value for predicting gastric cancer was 9.73.

Conclusions: The TyG index may be a novel predictive biomarker for gastric carcinogenesis. Notably, increase in the TyG index is significantly associated with gastric cancer.
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http://dx.doi.org/10.1007/s10120-021-01222-4DOI Listing
August 2021

Suppression of the hazardous substances in catalytically upgraded bio-heavy oil as a precautious measure for clean air pollution controls.

J Hazard Mater 2021 Jul 24;421:126732. Epub 2021 Jul 24.

School of Environmental Engineering, University of Seoul, 163 Seoulsiripdaero, Seoul 02504, Republic of Korea. Electronic address:

Bio-heavy oil (BHO) is a renewable fuel, but its efficient use is problematic because its combustion may emit hazardous air pollutants (e.g., polycyclic aromatic hydrocarbon (PAH) compounds, NO, and SO). Herein, catalytic fast pyrolysis over HZSM-5 zeolite was applied to upgrading BHO to drop-in fuel-range hydrocarbons with reduced contents of hazardous species such as PAH compounds and N- and S-containing species (NO and SO precursors). The effects of HZSM-5 desilication and linear low-density polyethylene (LLDPE) addition to the feedstock on hydrocarbon production were explored. The apparent activation energy for the thermal decomposition of BHO was up to 37.5% lowered by desilicated HZSM-5 (DeHZSM-5) compared with HZSM-5. Co-pyrolyzing LLDPE with BHO increased the content of drop-in fuel-range hydrocarbons and decreased the content of PAH compounds. The DeHZSM-5 was effective in producing drop-in fuel-range hydrocarbons from a mixture of BHO and LLDPE and suppressing the formation of N- and S-containing species and PAH compounds. The DeHZSM-5 enhanced the hydrocarbon production by up to 58.5% because of its enhanced porosity and high acid site density compared to its parent HZSM-5. This study experimentally validated that BHO can be upgraded to less hazardous fuel via catalytic fast co-pyrolysis with LLDPE over DeHZSM-5.
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http://dx.doi.org/10.1016/j.jhazmat.2021.126732DOI Listing
July 2021

Effective bioconversion of 1,3-propanediol from biodiesel-derived crude glycerol using organic acid resistance-enhanced Lactobacillus reuteri JH83.

Bioresour Technol 2021 Oct 2;337:125361. Epub 2021 Jun 2.

Microbial Biotechnology Research Center, Jeonbuk Branch Institute, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Jeongeup, Jeonbuk 56212, Republic of Korea. Electronic address:

Organic acids produced during the fermentation of lactic acid bacteria inhibit cellular growth and the production of 1,3-propanediol (1,3-PDO). Lactobacillus reuteri JH83, which has an increase of 18.6% in organic acid resistance, was obtained through electron beam irradiation mutagenesis irrelevant to the problem of genetically modified organisms. The maximum bioconversion of 1,3-PDO in fed-batch fermentation using pure glycerol by L. reuteri JH83 was 93.2 g/L at 72 h, and the productivity was 1.29 g/L·h, which achieved an increase by 34.6%, compared to that of the wild-type strain. In addition, the result of fed-batch fermentation for the production of 1,3-PDO using crude glycerol was not significantly different from that of pure glycerol. Additionally, transcriptome analysis confirmed changes in the expression levels of sucrose phosphorylase, which is a major facilitator superfamily transporter, and muramyl ligase family proteins, which protect lactic acid bacteria from various stressors, such as organic acids.
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http://dx.doi.org/10.1016/j.biortech.2021.125361DOI Listing
October 2021

Synthesis and characteristics of a rebaudioside-A like compound as a potential non-caloric natural sweetener by Leuconostoc kimchii dextransucrase.

Food Chem 2022 Jan 20;366:130623. Epub 2021 Jul 20.

Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea. Electronic address:

Stevioside (ST) is currently considered as a highly-demanded natural and zero-caloric replacer of sucrose with several health-promoting properties. Nonetheless, its bitter aftertaste limits its use in the food industry. Herein, glucosyl steviosides were synthesized using primarily a food-grade lactic acid bacteria, Leuconostoc kimchii dextransucrase and conversion yield (%) was 40.3%. A glucose moiety was transferred stereo-selectively to ST by α-1,6-linkage and this is the first report about obtaining rebaudioside A (Reb-A) like glucosyl stevioside-2 (STG-2). Glucosyl steviosides revealed greatly improved stability up to 120 °C and remained stable over 32.1% and 58.12% in the pH (1.4) compared with 30.55% of ST. Moreover, the glucosylated steviosides improved the stability, reaching 95% after 30 days and Reb-A like compound (STG-2) especially exhibited higher stability in commercial beverages. Furthermore, the glucosyl steviosides showed over 1.92- and 2.24-fold decreases than that of enzymatically modified ST in the glucose generation rate test.
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http://dx.doi.org/10.1016/j.foodchem.2021.130623DOI Listing
January 2022

Extract from Zanthoxylum piperitum Induces Apoptosis of AGS Gastric Cancer Cells Through Akt/MDM2/p53 Signaling Pathway.

Chin J Integr Med 2021 Jul 28. Epub 2021 Jul 28.

Department of Biological science and Biotechnology, College of Life science and Nano Technology, Hannam University, 1646 Yuseong-daero, Yuseong-gu, Daejeon, 34054, South Korea.

Objective: To determine the effect of Zanthoxylum piperitum extracet (ZPE) on apoptosis and analyze anticancer substances in ZPE, changes in proteins related to apoptosis, and pathological changes in tumors in mouse.

Methods: Fifteen 4-week-old female BALB/c nu/nu mice were divided into 3 groups depending on ZPE dose, with 5 in each group. AGS gastric carcinoma cells (1 × 10 cells/200 µL) were subcutaneously injected into the flank of each mouse. One week after the injection of AGS cells, ZPE was administered to the skin tissue [10 or 50 mg/(kg·d)] in the low- and high-dose groups, respectively for 20 days. Control animals were injected with vehicle only. After 3 weeks, the tumor was extracted and carried out for immunohistochemistry, the tendency of apoptosis and p53 in the body was checked using TdT-mediated dUTP nick-end labeling (TUNEL) assay. For 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, annexin V dead cell staining, cell cycle arrest and Western blotting, AGS gastric carcinoma cells were incubated with various concentrations of ZPE for 24 h. Cell survival rates were analyzed by MTT assays. Apoptosis was analyzed using annexin V dead cell staining and cell cycle arrest and measured using Muse cell analyzer.

Results: High performance liquid chromatography (HPLC) analysis showed that ZPE contained organic sulfur compounds such as alliin and S-allylcysteine. MTT assay results revealed that ZPE (10-85 µ g/mL) could effectively inhibit the growth of AGS gastric cancer cells at higher concentrations (P<0.05, P<0.01). The annexin V & dead cell staining assay and cell cycle arrest assay confirmed a dose-dependent increase in the apoptosis rate and G phase in ZPE (10-70 µ g/mL) groups. ZPE decreased the expression of anti-apoptotic proteins (p-Akt, p-MDM2, Bcl-2), while increased pro-apoptotic proteins (cleaved PARP, p53, pro-Caspase 3, Bax). TUNEL assays revealed an increase in cell apoptosis. Immunohistochemistry staining confirmed the involvement of p53.

Conclusion: ZPE decreases AGS cell proliferation and induces apoptosis by inhibiting Akt and MDM2 expression.
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http://dx.doi.org/10.1007/s11655-021-3486-8DOI Listing
July 2021

sp. nov., an endophytic bacterium isolated from .

Int J Syst Evol Microbiol 2021 Jul;71(7)

Korean Collection for Type Cultures (KCTC), Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup 56212, Republic of Korea.

An aerobic, Gram-stain-negative, weak-motile, short-rod-shaped bacterial strain, designated JBR3-12, was isolated from halophyte plants, and its taxonomic position was investigated by using a polyphasic taxonomic approach. The strain produced a pink pigment on tryptic soy agar and grew optimally at 25 °C, pH 8 and in the presence of 3 % (w/v) NaCl. Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strain JBR3-12 formed a lineage within the genus and was most closely related to DS-27 (98.0 %) and PB92 (97.6 %). The DNA G+C content of the genome was 41.3 mol%; the whole genome length was 5 426 070 bp. The major fatty acids of JBR3-12 were iso-C, summed feature 3 (comprising C 6 and/or C 7) and iso-C 3-OH. The predominant polar lipid was phosphatidylethanolamine. The predominant quinone was menaquinone-7. Based on its phenotypic, phylogenetic and genotypic features, strain JBR3-12 is proposed to represent a novel species of the genus , for which the name is sp. nov. The type strain is JBR3-12 (=KCTC 82363=NBRC 114901).
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http://dx.doi.org/10.1099/ijsem.0.004915DOI Listing
July 2021

Doping-Mediated Lattice Engineering of Monolayer ReS for Modulating In-Plane Anisotropy of Optical and Transport Properties.

ACS Nano 2021 Jul 23. Epub 2021 Jul 23.

Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea.

ReS exhibits strong anisotropic optical and electrical responses originating from the asymmetric lattice. Here, we show that the anisotropy of monolayer (1L) ReS in optical scattering and electrical transport can be practically erased by lattice engineering lithium (Li) treatment. Scanning transmission electron microscopy revealed that significant strain is induced in the lattice of Li-treated 1L-ReS, due to high-density electron doping and the resultant formation of continuous tiling of nanodomains with randomly rotating orientations of 60°, which produced a nearly isotropic response of polarized Raman scattering and absorption of Li-treated 1L-ReS. With Li treatment, the in-plane conductance of 1L-ReS increased by an order of magnitude, and its angle dependence became negligible. Our result that the asymmetric phase was converted into the isotropic phase by electron injection could significantly expand the optoelectronic applications of polymorphic two-dimensional transition metal dichalcogenides.
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http://dx.doi.org/10.1021/acsnano.1c05316DOI Listing
July 2021

Efficient gene transfer into zebra finch germline-competent stem cells using an adenoviral vector system.

Sci Rep 2021 Jul 20;11(1):14746. Epub 2021 Jul 20.

Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Korea.

Zebra finch is a representative animal model for studying the molecular basis of human disorders of vocal development and communication. Accordingly, various functional studies of zebra finch have knocked down or introduced foreign genes in vivo; however, their germline transmission efficiency is remarkably low. The primordial germ cell (PGC)-mediated method is preferred for avian transgenic studies; however, use of this method is restricted in zebra finch due to the lack of an efficient gene transfer method for the germline. To target primary germ cells that are difficult to transfect and manipulate, an adenovirus-mediated gene transfer system with high efficiency in a wide range of cell types may be useful. Here, we isolated and characterized two types of primary germline-competent stem cells, PGCs and spermatogonial stem cells (SSCs), from embryonic and adult reproductive tissues of zebra finch and demonstrated that genes were most efficiently transferred into these cells using an adenovirus-mediated system. This system was successfully used to generate gene-edited PGCs in vitro. These results are expected to improve transgenic zebra finch production.
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http://dx.doi.org/10.1038/s41598-021-94229-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8292312PMC
July 2021

Developmentally regulated GTP-binding protein 2 levels in prostate cancer cell lines impact docetaxel-induced apoptosis.

Investig Clin Urol 2021 Jul;62(4):485-495

Department of Urology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

Purpose: This study aimed to confirm the association between developmentally regulated GTP-binding protein 2 (DRG2) expression and docetaxel-induced apoptosis and to determine whether prostate cancer responses to docetaxel treatment differ with DRG2 expression.

Materials And Methods: PC3, DU145, and LNCaP prostate cancer cell lines were used. The MTT assay was used to determine cell viability. Western blotting analysis was performed using anti-DRG2 antibodies. Cells were transfected with 50 nmol DRG2 siRNA using an siRNA transfection reagent for DRG2 knockdown. The cell cycle was analyzed by using flow cytometry, and apoptosis was detected by using the Annexin V cell death assay.

Results: DRG2 expression differed in each prostate cancer cell line. Docetaxel reduced DRG2 expression in a dose-dependent manner. Upon DRG2 knockdown in prostate cancer cells, an increase in the sub-G1 phase was observed without a change in the G1 or G2/M phases. When 4 nM docetaxel was administered to DRG2 knockdown prostate cancer cell lines, an increase in the sub-G1 phase was observed without increasing the G2/M phase, which was similar to that in DU145 cells before DRG2 knockdown. In PC3 and DU145 cell lines, DRG2 knockdown increased docetaxel-induced Annexin V (+) apoptosis by 8.7 and 2.7 times, respectively.

Conclusions: In prostate cancer cells, DRG2 regulates G2/M arrest after docetaxel treatment. In prostate cancer cells with DRG2 knockdown, apoptosis increases without G2/M arrest in response to docetaxel treatment. These results show that inhibition of DRG2 expression can be useful to enhance docetaxel-induced apoptosis despite low-dose administration in castration-resistant prostate cancer.
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http://dx.doi.org/10.4111/icu.20200574DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8246011PMC
July 2021

Unusually High Ion Conductivity in Large-Scale Patternable Two-Dimensional MoS Film.

ACS Nano 2021 Jun 29. Epub 2021 Jun 29.

Department of Materials Science and Engineering, University of North Texas, Denton, Texas 76203, United States.

The advancement of ion transport applications will require the development of functional materials with a high ionic conductivity that is stable, scalable, and micro-patternable. We report unusually high ionic conductivity of Li, Na, and K in 2D MoS nanofilm exceeding 1 S/cm, which is more than 2 orders of magnitude higher when compared to that of conventional solid ionic materials. The high ion conductivity of different cations can be explained by the mitigated activation energy percolative ion channels in 2H-MoS, including the 1D ion channel at the grain boundary, as confirmed by modeling and analysis. We obtain field-effect modulation of ion transport with a high on/off ratio. The ion channel is large-scale patternable by conventional lithography, and the thickness can be tuned down to a single atomic layer. The findings yield insight into the ion transport mechanism of van der Waals solid materials and guide the development of future ionic devices owing to the facile and scalable device fabrication with superionic conductivity.
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http://dx.doi.org/10.1021/acsnano.1c04054DOI Listing
June 2021

Anisotropically Functionalized Aptamer-DNA Nanostructures for Enhanced Cell Proliferation and Target-Specific Adhesion in 3D Cell Cultures.

Biomacromolecules 2021 07 10;22(7):3138-3147. Epub 2021 Jun 10.

Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.

The development of supramolecular hydrogel scaffolds for the precise positioning of biochemical cues is paramount for applications such as tissue engineering. Nucleic acid engineering allows fabrication of three-dimensional (3D) nanostructures with high variability and nanoscale precision. In this study, aptamers were anisotropically functionalized onto branched DNA nanostructures to control their cell adhesion capability, and their efficiency as biological signal inducers for 3D cell cultivation was investigated. Each arm of the X-shaped DNA nanostructure (X-DNA) was functionalized with photo-cross-linkable or cell adhesion moieties, and the steric hindrance of the 3D DNA nanostructures on a cell was optimized. X-DNA nanostructures with cell-positioning parameters were rapidly photopolymerized to form hybrid hydrogels, and their effects on cell behaviors and positions were investigated. We observed that aptamer-functionalized X-DNA nanostructures exhibited significantly enhanced cell proliferation and provided homogeneous distribution and target-specific adhesion of encapsulated cells within hydrogel matrices. Overall, the anisotropic functionalization of DNA nanostructures provides a controllable function for the advancement of conventional 3D culture platforms.
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http://dx.doi.org/10.1021/acs.biomac.1c00619DOI Listing
July 2021

Ethanol Extract Induces Anoikis by Regulating the EGFR/Akt Pathway in HCT116 Colorectal Cancer Cells.

Front Oncol 2021 20;11:621346. Epub 2021 May 20.

Department of Biological Science and Biotechnology, College of Life Science and Nano Technology, Hannam University, Daejeon, South Korea.

ethanol extracts (SAE) is a species that has been shown to contain various physiological effects; however, its anticancer effects have yet to be revealed. We qualitatively evaluated β-sitosterol in SAE through high-performance liquid chromatography (HPLC). The cytotoxicity in HCT116 and HT29 colorectal cancer cells and CCD841 normal colon cells was confirmed through WST-1 assays. Selective cytotoxicity was observed in colorectal cancer cells, with greater cytotoxicity demonstrated in the HCT116 cell line. As such, the HCT116 colorectal cell line was selected for subsequent experiments. After HCT116 cells were treated with SAE, it was confirmed that the apoptosis rate was increased in a SAE dose-dependent manner through Annexin V assay. SAE further showed dose-dependent suppression of invasion through invasion assays. Anoikis induction through the EGFR/Akt pathway in HCT116 colorectal cancer cells was confirmed by Western blotting. The tumor suppressive effects of SAE was assessed using a xenograft model of human HCT116 colorectal cancer cells. As a result, we confirmed that SAE decreased tumor size in a dose-dependent manner and that p-EGFR and cleaved-caspase 3 in tumors were also regulated in a dose-dependent manner. This study showed that SAE, by containing β-sitosterol with proven anticancer effects, induces anoikis through the EGFR/Akt pathway in HCT116 colorectal cancer cells both and .
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http://dx.doi.org/10.3389/fonc.2021.621346DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8173041PMC
May 2021

Substitutional Vanadium Sulfide Nanodispersed in MoS Film for Pt-Scalable Catalyst.

Adv Sci (Weinh) 2021 Aug 3;8(16):e2003709. Epub 2021 Jun 3.

Department of Energy Science, Sungkyunkwan University, Suwon, 16419, Republic of Korea.

Among transition metal dichalcogenides (TMdCs) as alternatives for Pt-based catalysts, metallic-TMdCs catalysts have highly reactive basal-plane but are unstable. Meanwhile, chemically stable semiconducting-TMdCs show limiting catalytic activity due to their inactive basal-plane. Here, metallic vanadium sulfide (VS ) nanodispersed in a semiconducting MoS film (V-MoS ) is proposed as an efficient catalyst. During synthesis, vanadium atoms are substituted into hexagonal monolayer MoS to form randomly distributed VS units. The V-MoS film on a Cu electrode exhibits Pt-scalable catalytic performance; current density of 1000 mA cm at 0.6 V and overpotential of -0.08 V at a current density of 10 mA cm with excellent cycle stability for hydrogen-evolution-reaction (HER). The high intrinsic HER performance of V-MoS is explained by the efficient electron transfer from the Cu electrode to chalcogen vacancies near vanadium sites with optimal Gibbs free energy (-0.02 eV). This study provides insight into ways to engineer TMdCs at the atomic-level to boost intrinsic catalytic activity for hydrogen evolution.
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http://dx.doi.org/10.1002/advs.202003709DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8373103PMC
August 2021

Deep Learning-Assisted Quantification of Atomic Dopants and Defects in 2D Materials.

Adv Sci (Weinh) 2021 Aug 3;8(16):e2101099. Epub 2021 Jun 3.

Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea.

Atomic dopants and defects play a crucial role in creating new functionalities in 2D transition metal dichalcogenides (2D TMDs). Therefore, atomic-scale identification and their quantification warrant precise engineering that widens their application to many fields, ranging from development of optoelectronic devices to magnetic semiconductors. Scanning transmission electron microscopy with a sub-Å probe has provided a facile way to observe local dopants and defects in 2D TMDs. However, manual data analytics of experimental images is a time-consuming task, and often requires subjective decisions to interpret observed signals. Therefore, an approach is required to automate the detection and classification of dopants and defects. In this study, based on a deep learning algorithm, fully convolutional neural network that shows a superior ability of image segmentation, an efficient and automated method for reliable quantification of dopants and defects in TMDs is proposed with single-atom precision. The approach demonstrates that atomic dopants and defects are precisely mapped with a detection limit of ≈1 × 10 cm , and with a measurement accuracy of ≈98% for most atomic sites. Furthermore, this methodology is applicable to large volume of image data to extract atomic site-specific information, thus providing insights into the formation mechanisms of various defects under stimuli.
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http://dx.doi.org/10.1002/advs.202101099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8373156PMC
August 2021

Advanced atomic force microscopy-based techniques for nanoscale characterization of switching devices for emerging neuromorphic applications.

Appl Microsc 2021 May 26;51(1). Epub 2021 May 26.

School of Integrated Technology, Yonsei University, 85, Songdogwahak-ro, Yeonsu-gu, Incheon, 21983, Republic of Korea.

Neuromorphic systems require integrated structures with high-density memory and selector devices to avoid interference and recognition errors between neighboring memory cells. To improve the performance of a selector device, it is important to understand the characteristics of the switching process. As changes by switching cycle occur at local nanoscale areas, a high-resolution analysis method is needed to investigate this phenomenon. Atomic force microscopy (AFM) is used to analyze the local changes because it offers nanoscale detection with high-resolution capabilities. This review introduces various types of AFM such as conductive AFM (C-AFM), electrostatic force microscopy (EFM), and Kelvin probe force microscopy (KPFM) to study switching behaviors.
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http://dx.doi.org/10.1186/s42649-021-00056-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8155164PMC
May 2021

Seasonal and monthly variation in peak expiratory flow rate in children with asthma.

Asia Pac Allergy 2021 Apr 26;11(2):e19. Epub 2021 Apr 26.

Environmental Health Center for Atopic Diseases, Samsung Medical Center, Seoul, Korea.

Background: Although understanding the seasonal patterns of asthma deterioration is important to prevent asthma exacerbation, previous approaches have limitations in evaluating the actual trend of asthma exacerbation.

Objective: This study aimed to evaluate the seasonal and monthly variations in the peak expiratory flow rate (PEFR) among children with asthma.

Methods: A total of 89 patients with asthma were enrolled between December 2012 and March 2015. The PEFR in the morning and evening was recorded daily, and the percentage change in PEFR from baseline was calculated. Generalized estimating equation models were constructed after adjusting for age, sex, body mass index, and sensitization to house dust mites or pollen.

Results: The PEFR records of 11,222 person-days showed a significant decrease in the morning and evening in autumn than in winter by -1.9% (95% confidence interval [CI], -3.73 to -0.15) and -2.1% (95% CI, -3.80 to -0.37), respectively. The morning PEFR was significantly lower in April, August, October, and December than in January with changes of -4.2% (95% CI, -7.08 to -1.23) in April, -3.1% (95% CI, -5.79 to -0.47) in August, -3.7% (95% CI, -6.09 to -1.21) in October, and -1.9% (95% CI, -3.62 to -0.12) in December. The percentage change of evening PEFR significantly decreased by -3.3% (95% CI, -6.38 to -0.25) in April and by -3.3% (95% CI, -5.56 to -1.07) in October.

Conclusion: The PEFR in children with asthma was lower in autumn than in winter. In terms of monthly patterns, the PEFR was significantly reduced in April and October than in January. These results can serve as a basis for preventing asthma exacerbations by developing seasonal or monthly management strategies for children with asthma.
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http://dx.doi.org/10.5415/apallergy.2021.11.e19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8103013PMC
April 2021

Fc-fused IL-7 mobilizes long-term HSCs in a pro-B cell-dependent manner and synergizes with G-CSF and AMD3100.

Leukemia 2021 May 18. Epub 2021 May 18.

Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea.

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http://dx.doi.org/10.1038/s41375-021-01274-6DOI Listing
May 2021

Synthesis of improved long-chain isomaltooligosaccharide, using a novel glucosyltransferase derived from Thermoanaerobacter thermocopriae, with maltodextrin.

Enzyme Microb Technol 2021 Jun 24;147:109788. Epub 2021 Mar 24.

Department of Food Science and Technology, Chonnam National University, Gwangju, 61186, Republic of Korea. Electronic address:

Isomaltooligosaccharide (IMO), considered to be a prebiotic, reportedly has health effects, particularly in terms of digestion; however, the prebiotic effects of IMOs depend largely on the degree of polymerization. Currently, IMOs are commercially produced using transglucosidase (TG) derived from Aspergillus niger. Here, we report a novel Thermoanaerobacter thermocopriae-derived TG (TtTG) that can produce long-chain IMOs (L-IMOs) using maltodextrin as the main substrate. A putative carbohydrate-binding gene comprising carbohydrate-binding module 35 and glycoside hydrolase family 15 domain was cloned and successfully overexpressed in Escherichia coli BL21 (DE3) cells. The resulting purified recombinant enzyme (TtTG) had a molecular mass of 94 kDa. TtTG displayed an optimal pH of 4.0 (higher than that of commercial TG) and an optimal temperature of 60 °C (same as that of commercial TG). TtTG also enabled the synthesis of oligosaccharides using various saccharides, such as palatinose, kojibiose, sophorose, maltose, cellobiose, isomaltose, gentiobiose, and trehalose, which acted as specific acceptors. TtTG could also produce a medium-sized L-IMO, different from that by dextran-dextrinase and TG, from maltodextrin, as the sole substrate. Thus, the novel combination of maltodextrin and TtTG shows potential as an effective method for commercially producing L-IMOs with improved prebiotic effects.
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http://dx.doi.org/10.1016/j.enzmictec.2021.109788DOI Listing
June 2021

Impact of environmental factors in predicting daily severity scores of atopic dermatitis.

Clin Transl Allergy 2021 Apr;11(2):e12019

Department of Bioengineering, Imperial College London, London, UK.

Background: Atopic dermatitis (AD) is a chronic inflammatory skin disease that affects 20% of children worldwide. Environmental factors including weather and air pollutants have been shown to be associated with AD symptoms. However, the time-dependent nature of such a relationship has not been adequately investigated. This paper aims to assess whether real-time data on weather and air pollutants can make short-term prediction of AD severity scores.

Methods: Using longitudinal data from a published panel study of 177 paediatric patients followed up daily for 17 months, we developed a statistical machine learning model to predict daily AD severity scores for individual study participants. Exposures consisted of daily meteorological variables and concentrations of air pollutants, and outcomes were daily recordings of scores for six AD signs. We developed a mixed-effect autoregressive ordinal logistic regression model, validated it in a forward-chaining setting and evaluated the effects of the environmental factors on the predictive performance.

Results: Our model successfully made daily prediction of the AD severity scores, and the predictive performance was not improved by the addition of measured environmental factors. Potential short-term influence of environmental exposures on daily AD severity scores was outweighed by the underlying persistence of preceding scores.

Conclusions: Our data does not offer enough evidence to support a claim that weather or air pollutants can make short-term prediction of AD signs. Inferences about the magnitude of the effect of environmental factors on AD severity scores require consideration of their time-dependent dynamic nature.
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http://dx.doi.org/10.1002/clt2.12019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8099209PMC
April 2021
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