Comet Assay의 이해와 응용

Cuong, Dang Van,김충희,김나리,김의용,한진 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.3

Single cell gel(SCG) electrophoresis or 'Comet assay' is a rapid and very sensitive fluorescent microscopic method to examine DNA damage and repair at individual cell level. This assay has critically important applications in fields of toxicology ranging from aging and clinical investigations to genetic toxicology and molecular epidemiology. Since the introduction of the alkaline Comet assay in 1988, a number of advancements have greatly increased the flexibility and utility of this technique for detecting various forms of DNA damage (e.g., single- and double-strand breaks, oxidative DNA base damage, and DNA-DNA/DNA-protein/DNA-Drug crosslinking) and DNA repair in virtually any eukaryotic cell.

Effects of Annatto (Bixa orellana L.) Seeds Powder on Physicochemical Properties, Antioxidant and Antimicrobial Activities of Pork Patties during Refrigerated Storage

Cuong, Tran Van,Chin, Koo Bok Korean Society for Food Science of Animal Resource 2016 한국축산식품학회지 Vol.36 No.4

This study investigated the effect of the powder produced by ball-milling the outer layer of annatto (Bixa orellana L.) seeds on the physicochemical properties as well as the antioxidant and antimicrobial activities of pork patties over 14 d of refrigerated storage (4±1℃). Five pork patty treatments were produced containing three different concentrations of annatto seeds, 0.1, 0.25 and 0.5% (ANT0.1, ANT0.25, ANT0.5), 0.1% ascorbic acid (AA0.1), and a control (CTL). Based on the results, annatto seed powder appeared to show antioxidant activity. The Hunter color values of pork patties were affected by the addition of annatto seed powder, which increased the redness and yellowness values, but decreased the lightness of the patties (p<0.05). To evaluate the antioxidative effects of annatto on pork patties, thiobarbituric acid reactive substances (TBARS) and peroxide values (POV) were analyzed over 14 d of refrigerated storage. Treatments containing annatto seed showed lower TBARS and POV than control (CTL) samples (p<0.05). The volatile basic nitrogen (VBN) of the pork patties containing annatto seeds were lower than that of CTL at the end of storage (p<0.05). Although no differences in total bacterial counts were observed between control and treated patties, those containing annatto seeds had lower microbial counts for Enterobacteriacease than CTL or AA 0.1%. Therefore, annatto seed powder might be a good source of natural antioxidants for the production of meat products.

Formability and Effect of Hole Bridge in the Single Point Incremental Forming

Van-Cuong Do,샤오 샤오,안대철,김영석 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.3

This paper studies the mechanical properties, formability and effect of hole bridge (hole lancing) in the single point incremental forming for Al5052-O with the thickness of 0.8 mm. The mechanical properties, including anisotropy property and stress-strain relation, were evaluated by uniaxial tensile tests in three directions of 0°, 45°, 90° with the rolling direction. Varying wall angle conical frustum test was used to study the formability. The forming parameters of tool diameter, step depth, spin speed, and feed rate were optimized using multi-objective optimization with grey relational grade. The results show that the tool diameter strongly influences formability, springback and thickness reduction. To verify the effect of hole bridge on the formability, a predesigned hole bridge was machined by a laser on the blank shoulder nearby the forming periphery before forming. The optimized forming parameters found in previous step were applied for this test. As the result, the maximum forming angle was significantly improved in comparison with the non-hole-bridge part. Finite element simulation by ABAQUS explicit software was used to explain the strain evolution in the blank with cut-off hole of the incremental forming process. The simulation results were compared with experiment and discussed.

Development of Automatic Ship Berthing System Using Artificial Neural Network and Distance Measurement System

Van-Suong Nguyen,Van-Cuong Do,Nam-Kyun Im 한국지능시스템학회 2018 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.18 No.1

In the studies on an berthing control of ship, an artificial neural network (ANN) model is commonly employed as the main controller to control the rudder and the propeller. The existing ANN controllers that use the parameters consisting of the ship position and the ship heading as inputs cannot be applied to control automatically the ship into berth in different ports. To deal with this problem, the parameters, such as relative bearing and distance from ship to berth calculated by radar can be used as inputs for the controller. However, the calculation of these factors is not accurate because some errors arise on using radar for berthing process. This leads to the lack of confidence in ship berthing system using the parameters determined by radar. In this research, the neural network based-automatic berthing system is developed for ship by using the parameters which are measured by distance measurement system. By this proposed system, the ship is brought automatically into berth in different ports without retraining the neural network. In addition, this system guarantees that the parameters used for inputs of the neural network is measured exactly and continually. To validate the proposed algorithm, numerical simulations are carried out to two imaginary ports and a real port, and result showed the good performance of the proposed system for automatic ship berthing.

CodingGame: A Platform to Learn Programming via Games

Cuong Van Vu Nguyen,Tuan Manh Lai,Duong Anh Nguyen,Okjoo Choi 한국정보과학회 2017 한국정보과학회 학술발표논문집 Vol.2017 No.06

Chemical constituents and antioxidant activity of Ficus callosa.

Van Kiem, Phan,Cuong, Nguyen Xuan,Nhiem, Nguyen Xuan,Hang, Dan Thi Thuy,Nam, Nguyen Hoai,Ban, Ninh Khac,Minh, Chau Van,Bing, Zhou,Jang, Hae Dong,Kim, Young Ho Natural Product Communications 2011 Natural product communications Vol.6 No.2

<P>One new megastigmane glycoside, ficalloside (1), and eleven known compounds, were isolated from methanol extract of Ficus callosa leaves by repeated column chromatography. Their structures were established on the basis of spectral and chemical evidence. The antioxidant activities of these compounds were measured using the oxygen radical absorbance capacity (ORAC) assay. Compound 8 exhibited potent antioxidant activity of 10.6 microM trolox equivalents at the concentration of 2 microM. At this concentration, compounds 4-7 and 9-12 showed significant antioxidant activity with ranging of 2.1-6.1 microM trolox equivalents.</P>

High Performance NO₂ Gas Sensor Based on Pd-AlGaN/GaN High Electron Mobility Transistors with Thin AlGaN Barrier

Cuong Van Nguyen,Hyungtak Kim 대한전자공학회 2020 Journal of semiconductor technology and science Vol.20 No.2

We investigated the performance of NO₂ gas sensors based on AlGaN/GaN high electron mobility transistors (HEMT) with 10 nm AlGaN barrier. The sensors were designed to operate in μA range to reduce power consumption and realize good sensing performance. The gate area of the HEMT sensor was functionalized using a Pd and Pt catalyst layer for NO₂ detection to compare the performance between Pd and Pt catalysts. Pd-functionalized sensors demonstrated better sensing characteristics compared with Pt-functionalized sensors. When the sensors were exposed to 100 ppm of NO₂ at 300℃, the relative sensitivity of 53 % was measured with the response time and recovery time of 136 s and 196 s, respectively. Also, the sensor shows a significant change of drain current for 30 s exposure time in different concentrations from 10 to 100 ppm NO₂. These results suggest that Pd-AlGaN/GaN HEMT sensors with a thin barrier can be the great choice to detect NO₂ gas and they could be used in the harsh environment in real-time condition.

Removing the singularity of a penalty via thresholding function matching

Van Cuong Nguyen,Chi Tim Ng 한국통계학회 2019 Journal of the Korean Statistical Society Vol.48 No.4

By introducing the idea of thresholding function matching, it is illustrated that both bridge penalty and log penalty can be transformed so as to circumvent certain difficulties in numerical computation and the definition of local minimality. The fact that both bridge penalty and log penalty have derivatives going to infinity at zero. This hinders their applications in statistics although it is reported in the literature that they allow recovery of sparse structure in the data under some conditions. It is illustrated in the simulation studies that in the variable selection problems, penalized likelihood estimation based on the transformed penalty obtained by the proposed thresholding function matching method outperform those based on many other state-of-art penalties, particularly when the covariates are strongly correlated. The one-to-one correspondence between the transformed penalties and their thresholding functions are also established.

Spinel Nanoparticles ZnCo₂O₄ as High Performance Electrocatalyst for Electrochemical Sensing Antibiotic Chloramphenicol

Van-Cuong Nguyen,HyunChul Kim The Korean Electrochemical Society 2024 Journal of electrochemical science and technology Vol.15 No.1

In this study, ZnCo₂O₄ nanoparticles were synthesized via the coprecipitation method using different annealing temperatures from 200℃ to 800℃. By varying the treatment temperature, the morphology changed from amorphous to tetragonal, and finally to polygonal particles. As temperature increased, the sizes of the nanoparticles also changed from 5 nm at 200℃ to approximately 500 nm at 800℃. The fabricated material was used to modify the working electrode of a screen-printed carbon electrode (SPE), which was subsequently used to survey the detection performance of the antibiotic, chloramphenicol (CAP). The electrochemical results revealed that the material exhibits a good response to CAP. Further, the sample that annealed at 600℃ displayed the best performance, with a linear range of 1-300 μM, and a limit of detection (LOD) of 0.15 μM. The sensor modified with ZnCo₂O₄ also exhibited the potential for utilitarian application when the recovery in a real sample was above 97%.

Elucidation of the Inhibitory Mechanisms of Nipponoparmelia laevior Lichen Extract against Influenza A (H1N1) Virus through Proteomic Analyses

Cuong, Tran Van,Cho, Se-Young,Kwon, Joseph,Kim, Duwoon The Korean Society for Microbiology and Biotechnol 2010 Journal of microbiology and biotechnology Vol.20 No.1

Lichens contain diverse bioactive secondary metabolites with various chemical and biological properties, which have been widely studied. However, details of the inhibitory mechanisms of their secondary metabolites against influenza A virus (IAV) have not been documented. Here, we investigated the antiviral effect of lichen extracts, obtained from South Korea, against IAV in MDCK cells. Of the lichens tested, Nipponoparmelia laevior (LC24) exhibited the most potent inhibitory effect against IAV infection. LC24 extract significantly increased cell viability, and reduced apoptosis in IAV-infected cells. The LC24 extract also markedly reduced (~ 3.2 log-fold) IAV mRNA expression after 48 h of infection. To understand the antiviral mechanism of LC24 against IAV, proteomic (UPLC-$HDMS^E$) analysis was performed to compare proteome modulation in IAV-infected (V) vs. mock (M) and LC24+IAV (LCV) vs. V cells. Based on Ingenuity Pathway Analysis (IPA), LC24 inhibited IAV infection by modulating several antiviral-related genes and proteins (HSPA4, HSPA5, HSPA8, ANXA1, ANXA2, $HIF-1{\alpha}$, AKT1, MX1, HNRNPH1, HNRNPDL, PDIA3, and VCP) via different signaling pathways, including $HIF-1{\alpha}$ signaling, unfolded protein response, and interferon signaling. These molecules were identified as the specific biomarkers for controlling IAV in vitro and further confirmation of their potential against IAV in vivo is required. Our findings provide a platform for further studies on the application of lichen extracts against IAV.