Namhyun Chung

Prof. Dr. Namhyun Chung

orcid

Research Focus & Metrics

Academic Career Length

23Years (2004-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2014 in Environmental Toxicology and Chemistry
Verified
Journal Article
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JLJang Han Lee
Jang Han Lee
JJJae Eun Ju
Jae Eun Ju
BKByung Il Kim
Byung Il Kim
PPPyo June Pak
Pyo June Pak
ECEun-Kyung Choi
Eun-Kyung Choi
Namhyun ChungNamhyun Chung
Namhyun Chung

1 February 2015 in Brazilian Journal of Medical and Biological Research
Verified
Journal Article
Open access
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SPS.H. Park
S.H. Park
JSJ.H. Sung
J.H. Sung
EKE.J. Kim
E.J. Kim
Namhyun ChungNamhyun Chung
Namhyun Chung
Pancreatic cancer is the fourth leading cause of cancer death. Gemcitabine is widely used as a chemotherapeutic agent for the treatment of pancreatic cancer, but the prognosis is still poor. Berberine, an isoquinoline alkaloid extracted from a variety of natural herbs, possesses a variety of pharmacological properties including anticancer effects. In this study, we investigated the anticancer effects of berberine and compared its use with that of gemcitabine in the pancreatic cancer cell lines PANC-1 and MIA-PaCa2. Berberine inhibited cell growth in a dose-dependent manner by inducing cell cycle arrest and apoptosis. After berberine treatment, the G1 phase of PANC-1 cells increased by 10% compared to control cells, and the G1 phase of MIA-PaCa2 cells was increased by 2%. Whereas gemcitabine exerts antiproliferation effects through S-phase arrest, our results showed that berberine inhibited proliferation by inducing G1-phase arrest. Berberine-induced apoptosis of PANC-1 and MIA-PaCa2 cells increased by 7 and 2% compared to control cells, respectively. Notably, berberine had a greater apoptotic effect in PANC-1 cells than gemcitabine. Upon treatment of PANC-1 and MIA-PaCa2 with berberine at a half-maximal inhibitory concentration (IC50), apoptosis was induced by a mechanism that involved the production of reactive oxygen species (ROS) rather than caspase 3/7 activation. Our findings showed that berberine had anti-cancer effects and may be an effective drug for pancreatic cancer chemotherapy.

20 January 2017 in Scientific Reports
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JPJun-Hwan Park
Jun-Hwan Park
YJYe-Jin Jeon
Ye-Jin Jeon
CLChi-Hoon Lee
Chi-Hoon Lee
Namhyun ChungNamhyun Chung
Namhyun Chung
HLHoi-Seon Lee
Hoi-Seon Lee
The insecticidal toxicities of five essential oils against Pochazia shantungensis adults and nymphs, newly recorded pests, were evaluated. The LC50 values of Thymus vulgaris, Ruta graveolens, Citrus aurantium, Leptospermum petersonii and Achillea millefolium oils were recorded as 57.48, 84.44, 92.58, 113.26 and 125.78 mg/L, respectively, against P. shantungensis nymphs using the leaf dipping bioassay, and 75.80, 109.86, 113.26, 145.06 and 153.74 mg/L, respectively, against P. shantungensis adults using the spray bioassay method. Regarding volatile components identified in T. vulgaris oil, the LC50 values of carvacrol and thymol using the leaf dipping bioassay against P. shantungensis nymphs were 56.74 and 28.52 mg/L, respectively. The insecticidal action of T. vulgaris oil against P. shantungensis could be attributed to carvacrol and thymol. Based on the structure-toxicity relationship between thymol analogs and insecticidal toxicities against P. shantungensis nymphs similar to the LC50 values against P. shantungensis adults, the LC50 values of thymol, carvacrol, citral, 2-isopropylphenol, 3-isopropylphenol, and 4-isopropylphenol were 28.52, 56.74 and 89.12, 71.41, 82.49, and 111.28 mg/L, respectively. These results indicate that the insecticidal mode of action of thymol analogs may be largely attributed to the methyl functional group. Thymol analogues have promising potential as first-choice insecticides against P. shantungensis adults and nymphs.

30 March 2019 in Applied Biological Chemistry
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SHSanghyun Han
Sanghyun Han
ECEun Kyung Choi
Eun Kyung Choi
WPWoojun Park
Woojun Park
CYChongku Yi
Chongku Yi
Namhyun ChungNamhyun Chung
Namhyun Chung
Cracking of concrete over time, is a natural phenomenon. Longer service life of concrete structures is desirable. Self-healing concrete using bacteria, which could form CaCO3 crystals for crack sealing, has promised benefits to reduce cost for concrete maintenance, because cracks could be autonomously repaired without human intervention. However, because of harsh concrete internal environment render the effectiveness depending on the bacteria viability within concrete. In this study, expanded clay (EC) was used as a carrier, to protect bacteria (Lysinibacillus boronitolerans YS11) from the harsh environment during the process. Existence of bacteria inside EC was observed using electron microscopy. When exposed to bacterial solution of 1.0 × 109 cells/mL, bacterial density within EC reached approximately 0.82 × 107 cells/g of dry EC. Extent of bacterial viability within EC, submerged to solution containing 1.0 × 108 cells/mL, was 53.6% of free bacteria solution containing 1.0 × 107 cells/mL, as measured with fluorescein diacetate assay. When rate of calcium carbonate formation was measured with Ca2+ disappearance, rates were comparable between bacteria within EC (submerged to bacterial solution containing 1.0 × 108 cells/mL) and free bacteria (1.0 × 107 cells/mL). This finding indicates that bacteria with EC is very active for generation of CaCO3 within EC. All experimental results suggest that EC may be an adequate bacteria carrier for self-healing concrete.

23 May 2017 in Journal of Agricultural and Food Chemistry
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Journal Article
Closed access
JLJin-Woo Lee
Jin-Woo Lee
YKYoung Il Kim
Young Il Kim
CIChang-Nim Im
Chang-Nim Im
SKSung Wan Kim
Sung Wan Kim
SKSu Jin Kim
Su Jin Kim
Namhyun ChungNamhyun Chung
Namhyun Chung

4 June 2014 in Molecular and Cellular Biochemistry
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Journal Article
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SPS. H. Park
S. H. Park
JSJ. H. Sung
J. H. Sung
Namhyun ChungNamhyun Chung
Namhyun Chung