The aim of the study was to isolate microorganisms able to biodegrade phenol compound from mud samples of the laboratory wastewater discharge area in College of Agriculture, Can Tho University. Two mud samples of laboratorial discharge area and one soil smaple of grass at College of Agriculture, Can Tho University were enriched in the liquid minimal salt medium (MSM) containing 500 mg.L-1 phenol for enhancement of microbial density. The phenol concentration in liquid medium was determined by colorimetric method with Folin - Ciocalteu’s phenol reagent at wavelength 758 nm. The results showed that all the three microbial communities studied were able to biodegrade highly phenol compound in the liquid MSM and varied from 87.6% to 91.5% of the total initial concentration after 5 incubation days. Two yeast strains labeled as PS1.1 and PS6 among 28 microbial isolates showed their high biodegradation of phenol compound in liquid MSM containing 500 mg.L-1 phenol with a degradation percentage of 98.9% and 97.6%, respectively after 5 incubation days. Based on 28S-rRNA gene sequences, these two yeast strains showed 100% identity with Candida tropicalis and they were identified as Candida tropicalis PS1.1 and Candida tropicalis PS6, respectively.

The research is aimed to analyze gross primary production (GPP) of different land cover types in the Mekong Delta in 2018 using remote sensing data. This study used in total 92 MODIS MOD17A2 images with 500 m spatial resolution and 8-day composite,. The MRT tool was used to reproject MODIS product, LDOPE software were used to filter the good quality pixels for further analysis of GPP to assure the quality of research. The results showed that, GPP of forest was the highest (about 7.23 gC/m2/day) among land use types; rice crops and upland crop followed with GPP from 3-5 gC/m2/day and 3.12 gC/m2/day, respectively; GPP of shrimp farm areas was lowest (about 1 gC/m2/day). In general, the total amounts of GPP for whole Mekong Delta was about 3,107.37 tons C/year, whereas GPP of rice-crops were highest in year 2018. In detail, GPP of mono-rice crop (Winter Spring), double-rice crop (Winter Spring – Summer Autumn) and triple-rice crop (Winter Spring – Summer Autumn – Autumn Winter) were about 51.31 tons C/year (1.65%), 1,063.93 tons C/year (34.24%), and 1,161.52 tons C/year (37.38%), respectively; GPP of rice-upland crop was about 56.31 tons C/year (1.81%), rice – shrimp was about 166.63 tons C/year (5.36%), and forest was at 607.66 tons C/year (19.56%). In conclusion, different land cover types absorbs different amount of carbon and vary in different periods of year.

The study was conducted in May 2020 at 7 locations (D1-D7) in Vinh Dam port, Phu Quoc island, Kien Giang province to evaluate the diversity of phytoplankton and zoobenthos. Rapid measurement of environmental parameters showed that water quality in the study area has not signs of organic pollution (except D7). The results identified 97 phytoplankton species belonging to 6 phyla, 33 families and  38 genera; A total of 43 zoobenthos species belonging to 4 phyla, 6 classes, 33 families, and 37 genera were discovered in the study area. Density of phytoplankton and zoobenthos at the sampling points in the coastal area of Phu Quoc ranged from 12,097 to 119,709 individuals/L and from 40 to 490 individuals/m2, respectively. Calculating the diversity indexes pointed out that H’, J’ and Dv based on phytoplankton dividing sampling locations into two areas; in which D1 - D4 has relatively high and stable abundance (H ' = 3.42 - 3.77, J' = 0.84 - 0.91), D5 - D7 were less diverse and low stability (H' = 1.90-2.88, J' = 0.47 - 0.71). Analysis of H 'and DBP indicators shows that the diversity of zoobenthos in most locations in the study area is still low (H’tb = 1.66) and less sustainable (DBP = 0.64). The research results provide a database of species diversity of phytoplankton and zoobenthos at Vinh Dam, Phu Quoc, Kien Giang.

Crustaceans are commercial species in the coral reef ecosystem, however, the list of crustacean species has not fully updated yet. This study is aimed to evaluate and update the crustacean species composition in the coral reef ecosystems of Vietnam. Two projects were implemented I.2 in 2010, 2011, and 2015; and I.8 in 2015 and 2016 to collect crustacean samples by SCUBA diving method, then the animals were identified in the laboratory. A total of 106 crustacean species was identified belonging to 45 genera, 23 families and 2 orders. Among them, there were 55 species in the coastal coral reefs and 92 species in the coral reefs surrounding offshore islands. In this study, 23 crustacean species were updated and revised in the scientific names according to the WoRMS system (World Register of Marine Species). The Sorensen’s similarity indices of crustacean species ranged from 0.04 to 0.70 in the coastal coral reefs and from 0.61 to 0.93in the coral reefs surrounding offshore islands. The Shannon indiex (H') of the crustacean species in the coastal coral reefs and in the offshore island were 1.41 and 0.83, respectively. The results also showed that there were 9 highly commercial species of crustaceans which would be useful for aquaculture development.

The research was carried out to investigate fungal infections on striped catfish (Pangasianodon hypophthalmus) from larvae to fingerling. A total of 655 striped catfish were collected at Can Tho, Vinh Long, An Giang and Dong Thap provinces. The results showed that the prevalence of fungal infection was highest in fingerlings (22.8%), lowest in fry (16.9%), and larvae (20.5%). Fungal infection in the skin of larvae, fry, and fingerling was 40.3%, 35.1%, and 23.4%, respectively. The prevalence of fungal infection in the skin was higher than that in other organs such as gill, liver, kidney, and swim bladder. Four fungal genera were identified such as Fusarium sp. (43.9%), Aspergillus sp. (40.1%), Achlya sp. (11.5%), and Mucor sp. (4.5%). The results also indicated that Fusarium sp., Aspergillus sp., and Achlya sp. were found in most of the organs of fish. Mucor sp. isolated only in skins and gills of larvae and not found in fry and fingerling. Fusarium sp. was identified with a high infection rate in the swim bladder, especially in fingerling that clinical sign as swollen swim bladder fish.

The study was carried out to optimize in vitro culture conditions of increasing Streptomyces spp. growth rate. Physical and chemical conditions such as temperature, pH, salinity, C and N sources were performed on 3 strains of Streptomyces spp. including TV1.4, CM2.4 and DH3.4 in m-ISP2 C medium. After that, optimal C and N sources were selected to determine the optimal concentration for the growth of the studied bacterial strains. The experiments were designed in test tubes containing m-ISP2 medium with three replications. Bacterial growth was assessed by measuring optical density 600nm. The results showed that the optimal condition for TV1.4 strain grow best at pH 7, temperature 30℃, salinity 10‰, starch 2%, tryptone 2%. CM2.4 strain grow best at pH 8, temperature 40℃, salinity 10‰, starch 1%, tryptone 1% and strain DH3.4 grow well at pH 7, temperature 35℃, salinity 10‰, starch 1% and tryptone at 2% concentration. Among the 3 studied strains, Streptomyces TV1.4 was the best selected bacteria strain.

This study was carried out to investigate the current status, the need, and the effect of using medicinal plants in red tilapia (Oreochromis sp.) cage farming system in Vinh Long, Dong Thap and An Giang provinces. Interview data, including (i) general information of fish farms, (ii) current use of medicinal plants and (iii) potential use of medicinal plants were collected from 60 households in 3 mentioned provinces. Based on the farmer feedbacks, results showed that the percentage of farmers using herbs in Vinh Long, Dong Thap and An Giang was 70%, 95% and 60%, respectively. There were 15 plant species currently used in the red tilapia culture, in which garlic (Allium sativum), artichokes (Cynara scolymus), sakee naa (Combretum quadrangulare), purple cleome (Cleome chelidonii) and bush grape (Cayratia trifolia) were the most frequently used. Most of farmers assumed that enhancement of fish immune system, prevention of parasitic diseases, and improvement of water quality were the common reasons for the uses of medicinal plant extracts. Although the survey could not evaluate the cost and profit between use and non-use medicinal plants, this study provided fundamental understanding about the positive effects and potential of using medicinal plants in red tilapia culture.

Effects of different application frequencies of ozone disinfection on metamorphosis and survival rate of mud crab larvae (Scylla paramamosain) were carried out to improve the production and survival rate of mud crab larviculture. The experiment was conducted with four treatments in triplicates including (1) control (using iodine) and ozone disinfection at (2) every day; (3) every 2 days, and (4) every 3 days. The larvae were stocked in 50 L tanks at a density of 200 larvae/L. The ozone generator (4g/h) supplied ozone for the tanks through 3 vinyl pipes connected with air stones. The results showed that total bacteria count, Vibrio count and parasitic prevalence in ozone disinfected treatment were 2.2 x 103 cfu/mL, 0.20 x 103 cfu/mL and 4,86%, respectively; and were the highest compared to others (p

This study is aimed at evaluating financial investment effectiveness of dragon fruit orchard planted in Mang Thit district, Vinh Long province through directly interviews with 86 dragon fruit growers by using structured questionnaires. Indicators used to evaluate the investment effectiveness include total net present benefit (NPV), internal rate of return (IRR), benefit cost ratio (BCR) and payback period (PP). The analysis was conducted based on three scenarios: the first is base scenario of actual farmgate price and the other two hypothetical scenarios of decreased farmgate prices by 30% and 50% compared to actual price. The research results showed that dragon fruit cultivation requires large initial investment capital while the profits are also very high, e.g averaged annual net present value ranged from 192 million/ha/year to 1,2 billion/ha/year according to orchard yearold, meanwhile, the orchard owners need 2 years to payback their initial investemnt cost. However, when decreased prices by 30% and 50% compared to base scenario price, the investment effectiveness of the dragon fruit orchards decreases seriously, consequently newly established orchards could not be able to pay back the initial investment cost. In order to minimize risks of decline prices, dragon farmers are advised to pursue value chain linkage as well as apply off-season harvesting techniques for avoiding the surplus of supply over demand within a certain market.

This study aims to analyze the innovative performance of firms in Vietnam. The data of this study were comprised of manufacturing firms in Vietnam during 2015. The surveys covered part of a larger sample of manufacturing firms (442 firms) in Vietnam Enterprise Surveys by the World Bank. The results indicated that four activities affecting the innovative performance include: product or service innovation; marketing innovation; process innovation; and organizational innovation. Besides that, “product or service innovation” was the most impact on the innovative performance of firms in Vietnam.

The formulas for calculating the reduced matrix elements in the multipole form factors of the nucleus in  scattering at high energies were established in the framework of the unified electroweak theory. The multipole form factors of the nucleus  in the elastic scattering corresponding to the ground state were calculated from the given formulas. The contribution of weak interaction at high energies of hundreds GeV and more was also evaluated based on the newly calculated form factors.

This paper is to study the classification problem by Bayesian method in which estimating probability density function, and finding prior probability from real data are considered. The research also solves some complex calculations of this method by the built approximation and Matlab procedure. From the above improvements, an algorithm based on Bayesian method to classify a disease is proposed. This algorithm is applied specifically for a chronic kidney disease at the Can Tho Central General Hospital with real data. The outcome shows that the proposed algorithm has given good result in classifying this disease. Furthermore, this result also illustrates the advantages of the proposed method in comparison with the existing methods which are regularly used recently times.

Vorinostat is a histone deacetylase inhibitor which was approved by the US FDA in 2006 for the treatment of cutaneous manifestations in patients with cutaneous T-cell lymphoma. Among 18 HDAC enzymes, vorinostat is a potent inhibitor of the activity of HDAC1, HDAC2, HDAC3 and HDAC6. However, there have not been many published papers on the inhibitory capacity against HDAC8 (1T67) of vorinostat. In this study, the interactions of vorinostat with the enzyme HDAC8 (1T67) were performed and described by docking vorinostat into the active zone of the HDAC8 enzyme using Autodock. HDAC8 is a class I histone deacetylase implicated as a therapeutic target in various diseases, including cancer, parasitic infections and Cornelia de Lange syndrome. In invasive breast tumor cells, HDAC8 is among the three HDAC family members that are upregulated and driving invasiveness. The docking analysis shows vorinostat’s interactions with Zn+2 ion, Gly151, Gly304, Asp178, Tyr306, Phe207, Met274 and other less interacting residues. Therefore, the results could act as a momentum for further studies on the design of new isozyme-selective HDAC8 inhibitors.

The paper introduces the results on the morphology of Lai Giang river basin in Binh Dinh province using GIS. The morphological parameters of the river basin such as boundary, area, coefficient of symmetry, flow direction, mean elevation, slope,… These are calculated from digital elevation model (DEM) data with a resolution of 12,5 × 12,5 m for quite accurate quantitative results. The morphology of Lai Giang river basin has an area of ​​1404,41 km2; the average altitude of about 300 m; the length of the basin is about 87 km; there is great asymmetry between the left bank and right bank with catchment symmetry coefficient = 0,27; the average slope is 9,10o; … According to the flow direction, Lai Giang river basin is divided into two distinct regions (An Lao region and Kim Son region). Through determining the morphology of the Lai Giang river basin, it helps managers assess flood concentration, flood transmission, distribution of floods, as well as water reserves across the basin.

The purpose of the research is to analyze the financial efficiency and factors that affect the profitability of the main growing model of chives and basil based on a survey of 120 farmer households in Phuoc Hau commune, Long Ho district, Vinh Long province. Descriptive statistics, comparison of means and multiple regression methods were applied to analyze data in the study. It was found that both chive and basil cultivation models brought high profit. The profit (31.704.398 VND/1000 m2/year) of chive cultivation model is higher than the sam than that 0f (28.018.263 VND/1000 m2/year) of basil cultivation model, but the rate of return on input of chive cultivation model (1,147 times) is lower than that of basil model (1,557 times). The effective factors afecting the profit of Chives Agro-chemical electricity and hired labors costs. Similarly, the profit of basil model was influenced by seeds, fertilizers, Agro-chemicals, electricity and hired labors costs.

Bay Nui area of An Giang province has many delicious native rice varieties that have been preserved and inherited, notably the Nang Nhen rice variety, a traditional aromatic rice variety that has been associated for hundreds of years with the local Khmer people in Bay Nui region. Nang Nhen aromatic rice is not only a famous specialty rice because of its good rice quality and pleasant aroma, but it is only suitable for production in the field of Bay Nui region of Tri Ton and Tinh Bien districts. However, the Nang Nhen variety in the production is degenerating, the restoration of the Nang Nhen rice is carried out to maintain the good quality and yield characteristics of this variety. Three promising strains were selected with short growth duration and good quality, low amylose, with high yielding. In addition to traditional cultivation techniques, researching the planting season and applying supplemented with microbiological organic fertilizers achieves 5.51 tons/ha compared to traditional methods only have 4.59 tons / ha. Caring, harvesting and preserving fragrant Nang Nhen rice varieties in the right process is not only to keep the yield stable but also to maintain the characteristic aroma of the rice for a long time.

The study was conducted in the net house to evaluate salt tolerance capacity of three Napier grass species (Pennisetum sp.) including P. purpureum, P. glaucum and P. setaceum to serve as a base for selection salt-tolerant species to be grow in salt-affected soils. The plants were grown in hydroponics condition with Hoagland solution added five concentrations of 0, 5, 10, 15 and 20 g NaCl/L. The experiment was arranged in a factorial completely randomized design with three replications. The result showed that growth, fresh and dry biomass, growth rate and chlorophyll content (SPAD) of the three species were reduced as salinity concentration increased. P. setaceum had lower salinity tolerance capacity among the three studied species, which showed salt stress symptom of leaf rolling and wilting at 10 g NaCl/L, and all plant dried out and died at NaCl concentration of 15 and 20 g NaCl/L. The results indicated that P. purpureum and P. glaucum were the potential species to integrate with husbandry sector in the salt-affected soils under saline intrusion context in the Mekong Delta.

The purpose of this work was to evaluate the effects of vine pruning at 50 days after planting on the growth, tuberous yield and tuberous quality of three purple sweet potato (PSP)(Ipomoea batatas (L.) Lam.) varieties. The experimental site was located at Thanh Trung commune, Binh Tan district, Vinh Long province. The experiment layout was randomized complete block design, in factorial arrangement. Factor A included three purple sweet potato varieties used in the experiment (HL491 from Vietnam, PSP Lord (Lord) and PSP Malaysia which were imported from Japan and Malaysia). Factor B related to the pruning technique included keeping the vine length or pruning the vine (remained 50-60 cm of vine length) at 50 days after planting. The experiment had four replications with 10 m2 for each relication. The results showed that maintaining the rest main vines about 50-60 cm after pruning at 50 days after planting could affect to the growth characteristics and increased the number of tuberous roots, total and commercial yields as well as some quality contents such as dry weight, starch and anthocyanins contents of three selected PSP varieties. The highest vine length and some yield components (number of roots, merchandise yields and total tubeous root yield) were recorded from PSP Malaysia., The number of branches, total leaves, the anthocyanins and flavonoids contents extracted from the tubers of HL491 variety were higher than those from  other varieties.

This study was aimed to improve fruit yield and quality of the two soursop cultivars, viz. ‘Xiem’ and ‘Xiem Thai’. Randomized complete block design was employed in this study including 4 treatments, 5 replications, each experimental unit equaled to one tree. Two experiments, corresponding to the two cultivars i.e. ‘Xiem’ and ‘Xiem Thai’, were conducted on 5-year-old trees from August 2017 to February 2019 in Co Do district, Can Tho city. The four treatments included T1 – ‘open pollination’, T2- hand pollination using pollen from the same trees, T3- hand pollination using pollen from different trees, same cultivar, and T4- hand pollination using pollen from different cultivar (‘Xiem’, ‘Xiem Thai’). Results showed that hand pollination treatments increased the rate of fruit set, normal fruits, and decreased the rate of young fruit abscission. These resulted in increasing yield on both ‘Xiem’ and ‘Xiem Thai’ cultivar. Hand pollution using pollens from different trees, but similar cultivar brought about significant improvement of yield, which was 2.8, and 2.5 folds higher in the case of ‘Xiem’ and ‘Xiem Thai’, respectively. Hand pollination treatments did not affect the fruit parameters.

Post-weaning diarrhea (PWD) is one of the most common diseases endamaging the swine industry worldwide. Enterotoxigenic Escherichia coli (ETEC) is the main pathogen associated with PWD in piglets. The most important virulences are adhesion factors and enterotoxins. F4 and F18 are the two fimbriae frequently detected in ETEC. Vaccine is a powerful, cost-effect approach to defend against PWD. Especially, oral vaccine can stimulate mucosal immunity. Nowadays, ETEC/F4 vaccine is commercially available, but F18 fimbria is still difficult to induce mucosal immune response. In this study, a Pichia pastoris cell-surface display system of F18 subunit was created, and evaluated its expression on the cell wall. This surface expression system on P. pastoris’ cell wall could be exploited for budget yet efficient oral vaccine development.

The study was carried out on the basis of isolating and selecting of high activity bacteria strains for degrading carbosulfan from 3 rice crop soils in Hau Giang province. Investigating the ability of bacterial isolates to grow on the minimal mineral medium (MM) supplemented with carbosulfan concentration gradually increasing from 30 mg.L-1 to 60 mg.L-1 based on colony count method. Quantification of carbosulfan residues in liquid medium was done by mass chromatography technique. The research results showed that a total of 31 bacterial strains were isolated from rice-growing soils in Hau Giang province. Most of bacterial strains were short rods, negative Gram and move slowly. Sixteen bacterial strains could grow well in liquid MM supplemented with 20 mg.L-1 carbosulfan. Among them, 8, 6, 7 and 6 bacterial strains showed their well-growing in liquid culture media supplemented with 30, 40, 50, and 60 mg.L-1 carbosulfa after seventy-two hours of incubation, respectively. In particular, two bacterial strains designated as NB02 and NB04 could grow well in the liquid culture media containing 60 mg.L-1carbosulfan. They were identified as Stenotrophomonas panacihumi and Acinetobacter calcoaceticus, respectively. These two strains, in turn, degraded 82.3% and 75.0% of innitial concentration of carbosulfan in the liquid MSM after 7 incubation days under the laboratory conditions, respectively, with an initial concentration of 60 mg.L-1 carbosulfan.

Vegetarian food is being favored not only for religious purposes but also for health care. However, there have been many cases where the presence of meats in vegetarian foods has been detected due to the failure of during process vegetarian food or due to mixing to enhance the flavor of products. The use of DNA markers to identify ingredient composition has been successfully used in many cases. In this study, the KIT detects DNA from some common meats based on the multiplex PCR technique was developed and tested. The KIT can determine the presence of DNA of pork, beef, and chicken in vegetarian foods at a concentration of DNA 50 ng/reaction. This result could be potential to develop and apply PCR kit to check the presence of meats in food samples in general and vegetarian foods in particular.

The aim of this study was to evaluate the total polyphenol and flavonoid contents of Tagetes erecta L. (yellow and orange blossoms) petals extracts by using Folin-Ciocalteu assay and aluminium chloride colorimetric method respectively. Antioxidant activity, α-glucosidase inhibiting activity and the cytotoxicity were also evaluated in this study. The results revealed that the total polyphenol contents (150.18 ± 1.24 mg GAE/g DW), antioxidant activity (assessed by using DPPH method) and α-glucosidase inhibiting activity of T. erecta (yellow blossoms) petals in 70% ethanol were higher than those in the other three extracts including T. erecta (yellow blossoms) petals in 96% ethanol, T. erecta (orange blossoms) petals in 70% ethanol and 96% ethanol. There was a possitive correlation between α-glucosidase inhibiting capacity and flavonoid and polyphenol contents. These extracts of T. erecta in 500 µg/mL concentration exhibited cytotoxic activity against two human cancer cell lines, MCF-7 breast cancer cell lines and HeLa cervical cancer cell lines estimated by using sulforhodamin B assay. The greater amount of total polyphenol compounds leads to more powerful α-glucosidase inhibiting activity of T. erecta petals extracts.

The need for monitoring the spatial infrastructure is becoming an essential part of the management systems of large organizations. Although possessing many different specialized information systems, most of them ignore the spatial factors. That leads to a lot of restrictions related to the management of distributed objects as infrastructure. The paper has successfully proposed a process and model for standardizing (spatial and non-spatial) infrastructure data based on the principle of distributed ontology. The proposed model, based on two groups of Web services: Domain-based Web Services (DWS) and Web Features Services (WFS), achieves the goal of standardizing two specific infrastructure data groups, non-spatial and spatial, ready to operate in a distributed environment for rendering Web-based interactive maps.

The aim of the study was to assess the effects of processing conditions and pasteurization on the quality of straw mushroom in the acid solution. Straw mushrooms were treated by vacuum condition for 10 minutes, and blanched in GDL solution (pH = 3) at 100oC until the central temperature of product obtained at 90oC. The blanched products were stored in plastic bag, and filled by the GDL solution 1% with the ratio between mushroom and solution was 40:60. The plastic bags of straw mushrooms were pasteurized in the pasteurization system using hot water spray. The pasteurization conditions were: the flow rate of hot water was 0,6 m3/h, pasteurized temperature was 90oC and products obtained Fvalue = 18 minutes, the final product had good texture and color. After 4 weeks of the storage at ambient temperature, the pasteurized straw mushrooms had 6,0Í101 (cfu/g) of total aerobic bacteria, indicating the pasteurization parameters were safe for the straw mushroom product.

The study was conducted to isolate, screen and identify lactic acid bacteria strains capable of producing high lactic acid content from plant Typha orientalis and find out the optimal treatment for high and effective fermentation. From samples collected in Ca Mau, the CMT2 strain with the highest acid content was selected from 21 lactic acid bacteria strains were isolated. Identification of bacteria by using the 16S rRNA method indicated that the bacteria strain CMT2 belonged to Lactobacillus plantarum that was registered on GenBank with code MN841920. After six days of fermentation, using Design Expert 7.0 software with Box Henken format, it was determined that the optimal treatment for the fermentation of Typha orientalis by CMT2 strain was pH 4.87, salt concentration of 4.08%, bacteria density of 5.1*108 cell/mL with lactic acid content reached 5.71  g/L.

Surveying the revolutionary memoirs shows that epic tendencies are an important feature in reflecting reality and showing the image of people. The article is to highlight the manifestations of the epic tendency of memoirs through re-enacting important national events and building the image of the people with great stature. This feature of the memoir and some other genres show the movement and development trend of Vietnamese revolutionary literature.

Tuy Ly Vuong garden was built during the Nguyen dynasty (1802-1945), a symbol of the cultural and social characteristics of Vietnam during this period. Tuy Ly Vuong garden is a typical architectural work for the Vietnamese landscape construction art in the nineteenth century. This study has investigated, analyzed, and synthesized landscape tectonics art of Tuy Ly Vuong garden in terms of landscape layout, methods to handle landscape space, landscape architecture, and landscaped greenery. The results of this study have clarified the value of landscape tectonic art of Tuy Ly Vuong cover and are the reference database for the next studies in the field of classical landscapes in the world and Vietnam.

The development of technology and science as well as the growth of population cause the seriously polluted environment, especially the pollution of heavy metals. Synthesis of zeolites and their applications in adsorption, solid catalysts and ion exchange have been concerned. In this study, zeolite was synthesized from the precursor of sodium silicate originated from rice husk ash (RHA) without calcination by using hydrothermal method. The percentage of silica recovery from RHA without calcination was reached at about 90% when the optimal reaction conditions were at the ratio of RHA to NaOH = 1:10 (g/mL), the concentration of NaOH of 5 M, the reaction time of 3 h, the stirring speed of 300 rpm and the reaction temperature of 90oC. The parameters affected zeolite NaA/NaX synthesis such as ratio of SiO2 to Al2O3, the reaction temperature T1 (oC), reaction time t1 (h) and aging time t2 (h) were investigated. The results showed that crystal percentage of zeolite NaA/NaX was obtained at 52,7% during 4 h, 100oC, aging time of 12 h, ratio of Al2O3 to SiO2 of 2,5 and the ratio of Al:NaOH = 1:2 Although the crystal percentage of zeolite NaA/NaX in this study was not as high as that of other published researches, the in-situ synthesis used RHA without calcination and recovery of silica during the synthesis of zeolite NaA/NaX. Therefore, the synthesized process is environmental friendly as well as time and energy savings.

This study shows the results of factors affecting and methods to improve environmental durability of composite material based on crushed rice husk filler and polypropylene (PP). Methods to reduce water absorption of fiber-reinforced composite such as alkaline treatment, permanganate treatment, using coupling agent MAPE and covering composite specimens with a thin film. The results show that the thin coating of PP (3%) on the surface of composite materials is an effective method to improve the water absorption, in particular, a reduction of 70% in water absorption compared to the reference. Besides, the combination of MAPE (2%) into composite materials contributes to limiting the water absorption of the material; however, significantly in the first 7 days (reducing water absorption by 40% compared to samples without MAPE). The treatment of crushed rice husks with KMnO4 and NaOH is almost ineffective to reduce the water absorption of materials. Besides, titanium dioxide: TiO2 nano, TiO2 masterbatch PP-PE and TiO2 industry was used to decrease the impact of ultraviolet (UV) to the material. As a result, samples combined with 0.5% TiO2 masterbatch achieved the highest efficiency while retaining 98.67% tensile strength and 99% flexural strength after the survey time.

The study was conducted the presence of virulent genes and genetic relationship of S. Weltevreden and S. Typhimurium in pigs, husbandry environment, and wild animals in Vinh Long province. The PCR assay was used for determing the prevalence of pathogenic genes in 22 S. Weltevreden isolates and 19 S. Typhimurium isolates. The results of PCR showed the presence of 6/6 virulent genes surveyed from the two strains, in which gene sopB occupied the highest proportion in both S. Weltevreden (81.82%) and S. Typhimurium (94.74%). The ERIC-PCR method was done to clarify the genetic relationship of S. Weltevreden and S. Typhimurium, it indicated that S. Weltevrenden and S. Typhimurium isolates showed a relatively close genetic relationship. S. Weltevreden strains showed high phenotype diversity (21 phenotypes) and cross-infection through feces, waste water, cockroaches and especially from lizards which were considered as concerned hosts. S. Typhimurium strains also showed phenotype diversity (17 phenotypes) and cross-contamination through feces, insects such as flies and ants.

Escherichia coli O157:H7 is one of the most dangerous pathogens causing food-borne diseases on over the world, and cattle are the most popular reservoirs. A total of 24 E. coli O157:H7/H- strains (11 E. coli O157:H7 strains, 13 E. coli O157:H- strains) isolated from cattle in the Mekong Delta were clarified the prevalence of pathogenic genes (stx1, stx2, eae, EHEC-hlyA) and antimicrobial susceptibility with 12 antibiotics. By using PCR assay, the prevalence of these pathogenic genes in 24 E. coli O157:H7/H- strains were stx1 (29.17%), stx2 (33.33%), eae (37.50%), and EHEC-hlyA (33.33%); there were 7/11 of E. coli O157:H7 strains that had all four pathogenic genes observed. Those E. coli O157:H7/H- strains were completely susceptible (100%) to 7 antibiotics (ceftazidime, gentamycin, amikacin, kanamycin, tetracycline, ciprofloxacin, and norfloxacin). However, those strains showed relatively high resistance against ampicillin (50.00%), followed by nalidixic acid (16.67%), bactrim (12.50%), amox-clavulanic (8.33%), and ceftriaxone (8.33%). Moreover, those E. coli O157:H7/H- strains showed multidrug-resistant to 2-5 kinds of antibiotics in 5 multi-resistant phenotypes observed.

In order to contribute to proposing solutions to improve the performance of agricultural cooperatives in Vinh Long province in particular and the Mekong Delta in general, the research was conducted via group interviews with management boards of 75 cooperatives. The study shows that the performance scale of the cooperatives in Vinh Long province is still small in terms of market size, number of members, and charter capital. The number of services delivered by cooperatives is limited, many cooperatives have only one service. The research results also show that the financial efficiency indicators of the cooperatives are very low with net profits of only 129-177 million VND/year. In addition, the financial indicators of cooperatives with services are higher than cooperatives without services. The study also shows that the number of services, the scale of cooperatives, production costs, and the number of members are significantly and positively correltated with the net profit.

This research is aimed to estimate the willingness to pay of people in Can Tho city for Bus Rapid Transit (BRT) by employing Contingent Valuation Method (CVM) and Inferred Valuation (IV) in the form of double-bound dichotomous choice. The research also identified the determinants of the probability of willingness to pay for BRT using the Probit function. The primary data was surveyed by random interviews of 150 people who have been using buses in the central districts of Can Tho City, including Ninh Kieu, Binh Thuy, and Cai Rang. The results from conventional CVM find that mean WTP is 15,750 VND/ticket for a single trip. The 1st IV and 2nd IV forms approach result in the mean WTP values are 16,787 VND and 17,920 VND/ticket, respectively. The positive determinants of the probability of WTP are the number of family members, respondent’s income, and the status of bus using. Besides, the results of this study also recommend that CVM research in the future should employ the IV approach to check the validity of the conventional CVM.