Vietnam Academy of Science and Technology: Journals Online
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Analyzing 16S rRNA sequences from Vietnamese pathogenic Leptospira strains and in-silico prediction of potential antigenic epitopes on LipL21, LipL32 outer membrane lipoproteins
Full text linkLeptospirosis, a zoonosis caused by Leptospira, is recognized as an emergent infectious disease. In currently, the lack of adequate diagnostic tools, vaccines are an attractive intervention strategy. In this experiment, a 550 bp fragment of large ribosomal RNA gene (16S rRNA) was sequenced and constructed phylogenetic tree from a panel of six Vietnamese pathogenic strains of Leptospira spirochetes (e.g., Pomona, Canicola, Mitis, Ictero haemohagiae, Bataviae, and Grippotyphosa). The results showed a close relationship of L.Pomona_VN and L.Hardjo (bootstrap: 99%). L.Canicola_VN and L.Ictero haemohagiae_VN appeared to be weak related to the classic L.Canicola, L. Grippotyphosa, these assemblage have a bootstrap support of 62%. The other strains (L.Mitis_VN and L.Grippotyphosa_VN) were appeared monophyletic, while their sister group (L.Bataviae_VN) relationship found only weak support (bootstrap: 62%). We also selected six genes [e.g. the immunoglobulin like proteins A and B (LigA and LigB genes), outer membrane protein (OmpL1 gene), and lipopolysaccharide (LipL32, LipL41, and LipL21 genes)] and checked gene expression in these Leptospira strains by polymerase chain reaction (PCR) method. There were three genes (e.g., LipL32, LipL21, and LigA genes) expressed in all strains, OmpL1 gene occured in 4 strains (L.Bataviae_VN, L.Canicola_VN, L.Grippotyphosa_VN and L.Mitis_VN), whereas LipL41 and LigB genes did not appear in any Leptospira strains. A multi-antigenic epitope potential of two gene (Lip L21 and Lip L32) was predicted by bioinformatic tools for designing a recombinant vaccine against leptospirosis. There were 3 multi-epitope regions (1 region and 95 antigenic epitope for B and T cells of LipL21 peptide; 2 regions and 124 antigenic epitope for both B and T cells of LipL32 peptide). It should be more of the deeply molecular biology studies to confirm the level agglutinating, antigen cleavage, peptide specificity matrices as well as neutralizing antibodies in the immune responses of DNA vaccine of these genes
RELATIONSHIPS OF TEMPERATURE AND HUMIDITY TO THE BIODEGRADATION OF PETROLEUM HYDROCARBONS IN SOILS
Full text linkThis work focused on monitoring CO2production, microbial growth and residual hydrocarbon concentration during bioremediation experiments performed on laboratory soil microcosms. A natural soil was artificially contaminated with hexadecane and adjusted with inorganic nutrients to stimulate biodegradation. Microbial growth, CO2production and residual hexadecane were periodically monitored at different soil water contents ranging from 0.15 to 0.25 g water g_1 of dry soil and at different temperatures ranging from 20 to 25oC. Results showed that the humidity has a greater effect on microbial activity and contaminant degradation than the temperature. The study established the experimental regression equation of temperature and humidity to the hexadecane mineralization rate, an important parameter in assessing the ability to convert organic carbon into inorganic carbon. The difference between the results of the hexadecane mineralization rate obtained from the experiment and calculated from the regression equation is not too high, from 2% to 20%
MODIFICATION OF GRAPHENE OXIDE BY CURCUMIN AND APPLICATION IN POLYURETHANE COATING
Full text linkCurcumin modified graphene oxide (GO-CR) was prepared using adsorption method and polyurethane (PU) coating containing 0.3 wt% GO-CR was prepared on carbon steel. Synthesized GO-CR was characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and zeta potential measurement. Corrosion protection property of polyurethane coating containing GO-CR was evaluated and compared with blank polyurethane coating and coating containing GO by electrochemical impedance spectroscopy. The results showed that GO-CR has layer structure like GO with lower crystallinity. In GO-CR structure curcumin was attached on GO surface. The presence of curcumin on GO-CR surface provided corrosion inhibition action for PU coating and also improved the dispersion of GO in PU coating
Tourism climate index on the Co To islands of Quang Ninh province, Vietnam
No full textTourism is one of the spearhead economic sectors of every country in the world and sensitive to weather conditions. The climate is one of the most important factors for each destination for vacation and recreation. Almost the measures are primarily based on particular local weather and climate, and part of them deals with energy balance estimation to assess thermal comfort. Tourism climate indicator developed by Mieczkowski (1985) incorporates 7 climate variables (average temperature, maximum temperature, average humidity, minimum humidity, precipitation, number of sunny hours, wind speed) relevant to general tourism activities is used to assess potential impacts of climate change on tourism climate resources of Co To islands in the Tonkin Gulf of Vietnam. The monthly tourism climate indicator classification results show that the tourism potentials of Co To islands range from unfavorable (30–39) to very good (70–79) in March, April, November and December. Daily tourism climate indicator classification results indicate that tourism potentials are from extremely unfavorable (20–29) to excellent (80–89). The days at very good to excellent for travel are on 2nd, 3rd, 5–7th of January; 6–8th and 20–28th of February; 1st–8th, 12–17th and 20–28th of March; 1st–2nd,4–13th, 15–18th of April; 21st–24th of September; 1st–4th, 6th, 8–10th, 12th, 13th of November; 1st–26th of December. These findings are important for future research in assessing current and future climate suitability for sustainable tourism development
Species composition and distribution of marine macro algae at Co To and Thanh Lan archipelago
No full textThis paper exhibites species composition and distribution of marine seaweed at 10 sites of Co To and Thanh Lan islands in May 2019. The studies record 76 species of marine algae in the area, belonging to four divisions: Cyanophytes, Rhodophytes, Ochrophytes and Chlorophytes. Among them, five species are classified into Cyanophytes (comprising 6.6% of total species); thirty-four species into Rhodophytes (44.7%); twenty-one species into Ochrophytes/Phaeophytes (27.6%) and sixteen species into Chlorophytes (21.1%). The species composition of marine seaweeds in Co To and Thanh Lan shows significant differences as follows: 22 species (sites number 4 and 10) to 58 species (site number 2) and the average value is 38.7 species per site. Sørensen similarity coefficient fluctuates from 0.33 (sites number 5 and 10) to 0.84 (sites number 1 and 3) and the average value is 0.53. The current investigations show that four species of twenty-one species are collected in the littoral zone and forty-two species in the sub-littoral zone (in which there are thirteen species distributed in both littoral zone and sub-littoral zone). The algal flora in Co To and Thanh Lan is characterized by subtropics
Wave overtopping and splash-up at seawalls with bullnose
No full textSeawalls have been erected to protect hundreds of towns and tourism areas stretching along the coast of Vietnam. During storm surges or high tides, wave overtopping and splash-up would often threaten the safety of infrastructures, traffic and residents on the narrow land behind. Therefore, this study investigates these wave-wall interactions via hydraulic small scale model tests at Thuyloi University. Remarkably, the structure models were shaped to have different seaward faces and bullnoses. The wave overtopping discharge and splash run-up height at seawalls with bullnose are significantly smaller than those without bullnose. Furthermore, the magnitude of these decreasing effects is quantitatively estimated
Contemporary movement of the Earth's crust in the Northwestern Vietnam by continuous GPS data
No full textThe paper presents an estimation of the Earth’s crustal motion from the continuous GPS data at 6 stations (MTEV, MLAY, DBIV, TGIV, SMAV and SLAV) in the Northwestern and at PHUT (Hanoi) station using GAMIT/GLOBK software. The absolute displacements of the Earth’s crust at 7 stations in the IGS14 frame are respectively: 34.10±0.71 mm/yr (DBIV), 34.31±0.65 mm/yr (PHUT), 34.51±0.75 mm/yr (SMAV), 34.55±0.80 mm/yr (MLAY), 34.80±0.72 mm/yr (TGIV), 34.93±0.99 mm/yr (SLAV) and 35.59±0.73 mm/yr (MTEV), in the southeastward with the azimuth range 104-108o. The Son La fault is a right-lateral slip fault with a shear amplitude of ~1.5 mm/yr. The Lai Chau-Dien Bien fault is a left-lateral slip fault with a shear amplitude of ~1.9 mm/yr. Although the absolute velocities at the DBIV, SMAV, SLAV, TGIV and MLAY stations are evaluated with the error 1 mm/yr, the relative displacement on the Ma River fault is of ~0.5 mm/yr, and it seems that we still do not have a reliable assessment of the slip rate on the Ma River right-lateral slip fault
Identify some aerodynamic parameters of a airplane using the spiking neural network
No full textThe main objective of this study is to propose a method for identifying aerodynamic coefficient derivatives of aircraft attitude channel using spiking neural network (SNN) and Gauss-Newton algorithm based on data obtained from actual flights. Out of these, the SNN multi-layer network was trained by Normalized Spiking Error Back Propagation, in which, in the forward propagation period, the time of output spikes is calculating by solving quadratic equations instead of detection by traditional methods. The phase of propagation of errors backward uses the step-by-step calculation instead of the conventional gradient calculation method. SNN in combination with Gauss-Newton iterative calculation algorithm proposed in this study enables the identification of aerodynamic coefficient derivatives in a nonlinear model for aerodynamic parameters with higher accuracy and faster calculation time. The identification results are compared with the results when using the Radial Basis Function (RBF) network to prove the algorithm efficiency
Facile Synthesis of CuO/ITO Film Via the Chronoamperometric Electrodeposition for Nonenzymatic Glucose Sensing
Full text linkWe report on the synthesis of copper (II) oxide (CuO)/indium tin oxide (ITO) electrode via the electrochemical deposition method using a CuSO4 solution and then thermal oxidation in air at temperature of 400 oC for 2 h. The crystalline structure and morphology of CuO were characterized by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The electrochemical properties of the CuO/ITO electrode to glucose in the alkaline medium of 0.1 M NaOH solution were investigated by cyclic voltammetry (CV) and Chronnoamperometry. The CuO-N/ITO electrode showed the best electrochemical properties for glucose detection in comparison to the others. Chronnoamperometry of CuO-N/ITO electrode to the glucose response showed excellent stability, the linear range of 1 mM to 3600 mM with high sensitivity of 283.6 mAcm-2mM-1 and 0.61 mM of the detection limit (S/N=3). A good response of the CuO-N/ITO electrode, which was investigated for different human serum samples, indicates a high potential of its towards a glucose sensor for analysis in real examples
Optimization and Characterization of Paper-based SERS Substrates for Detection of Melamine
No full textA flexible low-cost paper-based surface enhanced Raman scattering (SERS) substrate was successfully manufactured by a direct chemical reduction of silver nanoparticles (AgNPs) onto a common commercially available filter paper. Characterization of fabricated paper-based SERS substrate and the influences of the silver nitrate concentration, type of paper on SERS signal were systematically investigated. In order to fabricate SERS substrates with the highest quality, a suitable one from four different types of filter papers was chosen. The prepared SERS substrates have capability for detecting food toxic chemicals. The test of detecting melamine in aqueous solution was successfully demonstrated with the limit of detection for melamine is 10-7M