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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>
Nguyen Phuong Thao,Bui Thi Thuy Luyen,Nguyen Thi Thanh Ngan,Le Duc Dat,Nguyen Xuan Cuong,Nguyen Hoai Nam,Phan Van Kiem,Seok Bean Song,Chau Van Minh,김영호 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.5
Peroxisome proliferator-activated receptors(PPARs) are ligand-activated transcription factors thatregulate the expression of multiple genes involved inmetabolic, anti-inflammatory, and developmental processes. This study evaluated the PPARs transactivationaleffects of thirteen cembranoid diterpenoids 1–13 from thesoft coral Lobophytum crassum, using PPAR-responsiveelements–luciferase reporter and GAL4–PPAR chimeraassays. All isolated compounds activated the transcriptionof PPARs in a dose-dependent manner, with EC50 valuesranging from 2.07 ± 1.73 to 130.20 ± 1.85 lM. Moreover,compounds 6–9 affected the transactivation of allthree PPAR types, PPARa, c, b(d), in a dose-dependentmanner, with EC50 values in a ranging from 11.92 ± 1.23to 122.50 ± 2.12 lM. These results provide a scientificrationale for further studies on the soft coral L. crassum andits diterpenoid constituents to develop medicinal productsagainst inflammatory and metabolic diseases.
Nguyen Phuong Thao,Bui Thi Thuy Luyen,Chau Ngoc Diep,Bui Huu Tai,김은지,강희경,이상현,장해동,Nguyen The Cuong,Nguyen Van Thanh,Nguyen Xuan Cuong,Nguyen Hoai Nam,Chau Van Minh,김영호 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.4
This study performed phytochemical and bioactiveassessments of the mangrove Lumnitzera racemosaWilld. leaves. Bioassay-guided fractionation of the methanolicextracts led to the identification of thirty-six compounds(1–36), their structures were elucidated using detailed NMRspectroscopic and MS analysis. The extracts, fractions, andthe isolated compounds were screened for potential antioxidantand cytotoxic activities. Antioxidant assays wereperformed using peroxyl radical-scavenging and reducingassays, whereas cytotoxicity was measured using MTTassays in HL-60 and Hel-299 cell lines. The methanolicextract, CH2Cl2 and n-BuOH fractions (10.0 lg/mL)exhibited potent antioxidant activity, with Trolox equivalent(TE) values of 24.94 ± 0.59, 28.34 ± 0.20, and27.09 ± 0.37 (lM), respectively. In addition, the isolatedcompounds exerted cytotoxic effects in a dose-dependentmanner; compounds 1 and 14 exhibited the most potentcytotoxicity in HL-60 cells, with IC50 values of 0.15 ± 0.29and 0.60 ± 0.16 lM, respectively. To clarify the mechanism(s) behind these cytotoxic effects, we measured thetime-dependent changes in apoptotic markers including thecondensation and fragmentation of nuclear chromatin, andthe downregulation of p-ERK1/2, p-AKT, and c-Myc levels.
Nguyen, Van-Suong,Do, Van-Cuong,Im, Nam-Kyun Korean Institute of Intelligent Systems 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.
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.
Cytotoxic Oleane-type Triterpene Saponins from Glochidion eriocarpum
Nguyen Xuan Nhiem,김영호,Vu Kim Thu,Phan Van Kiem,Chau Van Minh,Bui Huu Tai,TRANHONG QUANG,Nguyen Xuan Cuong,Pham Hai Yen,Hye-Jin Boo,강정일,강희경 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.1
The anticancer activity of ten compounds from the aerial parts of Glochidion eriocarpum were evaluated on two human cancer cell lines, HL-60 and HCT-116. Compounds 1-4 displayed highly potent cytotoxic activity on the HCT-116 cancer cell line with IC50 values ranging of 0.41~1.16 μM. Compounds 1-4 significantly inhibited the HL-60 cell line with IC50 values ranging of 4.51~6.33 μM. These results suggested that the benzoyl group at the C-22 position in oleane-type triterpene saponins was essential for cytotoxicity towards tumor cells. Moreover, compounds 2 and 3 showed more potent cytotoxicity than compounds 1 and 4 against HL-60 and HCT-116 cells. With respect to the mechanism underlying cytotoxicity, compounds 1-4 increased chromatin condensation, a typical apoptotic characteristic in HL-60 and HCT-116 cells. In the mechanism of apoptosis induction, compounds 1-4 reduced Bcl-2expression, whereas the expression of Bax was increased compared to controls in HCT-116 cells. In addition, compounds 1-4 decreased the level of procaspase-3. The cleavage of poly (ADP-ribose) poly merase (PARP), a vital substrate of effector caspase, was observed in HCT-116 cells. Furthermore, the induction of apoptosis was also accompanied by an activation of extracellular signal-regulated kinase (ERK) and p38 kinase in HCT-116 cells. These findings provide evidence demonstrating that the pro-apoptotic effects of compounds 1-4 are mediated through the activation of ERK and p38 in HCT-116 cells.
Nguyen Duc Cuong,Tran Thai Hoa,Dinh Quang Khieu,Nguyen Duc Hoa,Nguyen Van Hieu 한국물리학회 2012 Current Applied Physics Vol.12 No.5
The development of a low cost and scalable gas sensor for the detection of toxic and flammable gases with fast response and high sensitivity is extremely important for monitoring environmental pollution. In this work, we introduce two different synthesis pathways for the preparation of scalable Fe2O3nanoparticles for gas sensor applications. One is co-precipitation and the other is hydrothermal method. The gas sensing properties of the a-Fe2O3 nanoparticles (NPs) fabricated by different synthesis pathways were studied and compared. The performance of the NPs in the detection of toxic and flammable gases such as carbon dioxide, ammonia, liquefied petroleum gas, ethanol, and hydrogen was evaluated. The Fe2O3 NP-based gas sensors exhibited high sensitivity and a response time of less than a minute to analytic gases. However, the NPs fabricated by the one-step direct method exhibited higher sensitivities than those generated by the a-Fe2O3 NPs obtained by co-precipitation synthesis possibly because of their nanoporous structure. This performance is attributed to the large specific surface area of the NPs, which results in higher sensitivity. The development of a low cost and scalable gas sensor for the detection of toxic and flammable gases with fast response and high sensitivity is extremely important for monitoring environmental pollution. In this work, we introduce two different synthesis pathways for the preparation of scalable Fe2O3nanoparticles for gas sensor applications. One is co-precipitation and the other is hydrothermal method. The gas sensing properties of the a-Fe2O3 nanoparticles (NPs) fabricated by different synthesis pathways were studied and compared. The performance of the NPs in the detection of toxic and flammable gases such as carbon dioxide, ammonia, liquefied petroleum gas, ethanol, and hydrogen was evaluated. The Fe2O3 NP-based gas sensors exhibited high sensitivity and a response time of less than a minute to analytic gases. However, the NPs fabricated by the one-step direct method exhibited higher sensitivities than those generated by the a-Fe2O3 NPs obtained by co-precipitation synthesis possibly because of their nanoporous structure. This performance is attributed to the large specific surface area of the NPs, which results in higher sensitivity.
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.