Marine algal species and their distribution in Phu Quoc marine protected area

This article presents the raw data in relation to the status of, and the distribution of, the 41 marine algal species occurring around and within the An Thoi coral reef strictly protected zone, Phu Quoc Marine Protected Area. The data, which were collected in May 2017, include the detailed description of the locations, the oceanographical conditions, and the photographs of the 41 marine algal species. For more insight, please see “Marine algal species and marine protected area management: A case study in Phu Quoc, Kien Giang, Vietnam” Huynh and Nguyen, 2019

Ecological Engineering and Restoration of Eroded Muddy Coasts in South East Asia: Knowledge Gaps and Recommendations

Ecological engineering (EE) was employed for developing strategies for stabilizing eroded muddy coasts (EMCs). However, there was a limited analysis of these EE strategies with respect to design, performance, and lessons learned. This study employed a critical review for addressing the limitations. There were four EE models designed with different restoration interventions for stabilizing EMCs. The models using active interventions have not been cost-effective in controlling erosion because the interventions failed to achieve their goals or were costly and unnecessary. Of the two passive intervention models, the one with structures constructed from onshore proved to be more cost-effective in terms of construction costs, the survival rate of transplanted seedlings, and levels of sea mud accumulation. Interventions with adequate consideration of the muddy coastal ecological processes and the ecological reasoning for the positioning of these interventions play a crucial role in stabilizing EMCs. A passive restoration model using gradually expanded interventions should be promoted in order to ensure sustainable management of EMCs in the future

Modeling of parallel power MOSFETs in steady-state

In high-power applications, multiple power MOSFETs are connected in parallel and treated as a single switch in order to handle much larger total currents. In this paper, a parallel power MOSFETs model from the turnoff state until they reach their steady state is introduced. The model represents the relationship between each power MOSFET's gate voltage and the current distribution among them. The study's key purpose is to use the model for dealing with the asymmetry in sharing current and power loss between these semiconductor devices during the steady state region.Comment: 10 pages, 7 figures, The 2023 INTERNATIONAL SYMPOSIUM ON ADVANCED ENGINEERING (ISAE2023

Identifying biofilm forming bacteria in cow milk in Mekong Delta, Viet Nam

Bacterial biofilms are agglomeration of bacterial cells, stuck to the material surfaces of material in wet environments and formed by a self-produced matrix. The formation of bacterial biofilms is a great risk for the milk processing industry, as the survival of many bacterial species in cow milk may lead to many problems such as microbial spoilage, deterioration in quality, and consumer health risks. This study aimed to identify biofilm formation bacteria from cow milk. The experiment included isolation; biofilm forming assay in 96-well microtiter plates and the identification of microbial isolates using classical and molecular biological methods. A total of 14 bacterial isolates from 10 cow milk samples were evaluated for their biofilm formatting ability. Among them, four isolates were identified as moderate and strong biofilm producers. These four isolates belong to the genera Serratia and Aeromonas. Out of the 4 isolates, Serratia marcescens VL41 was classed as a strong biofilm producer while Aeromonas veronii ST15, Aeromonas sp. ST17, Serratia marcescens VL13 were classed as moderate biofilm producers respectively. The findings of this study suggest that it is necessary to discover the contamination causes and prevention of genera Serratia, and Aeromonas into cow milk

Agrobacterium-mediated transformation of Nang Thom Cho Dao, an indica rice variety

Agrobacterium-mediated transformation is the most efficient method to transfer gene of interest into the plant genome. However, the transformation efficiency of this method with indica rice varieties is still low and needs to be improved. In this study, the Agrobacterium-mediated method was used to transfer reporter genes into the Nang Thom Cho Dao, an indica rice variety. Different transformation parameters, such as selection to used hygromycin at concentrations of 0, 25, 30, 40, and 50 mg/L, bacterial density, and infected duration, were tested and optimized. The results showed that 30 mg/L of hygromycin was the most appropriate concentration for selecting transgenic callus in Nang Thom Cho Dao. In addition, the highest transformation efficiency of this Nang Thom Cho Dao rice cultivar was observed at the bacterial suspension density OD600nm of 0.1, the infected duration of 20 minutes, and the 3-day co-culture period. The presence and expression of transgenes were confirmed by gus staining and PCR with specific primers for hptII and gus genes. This transformation procedure should be used for further studies in genetic engineering of Nang Thom Cho Dao and other indica rice varieties

AN INVESTIGATION INTO THE COMMON ERRORS OF WORD FORM USED IN WRITING OF THE FRESHMEN: A CASE STUDY

English has been used all across the world, including in Vietnam. From middle school to high school and even university, Vietnamese students have numerous opportunities to engage with English grammar, but there is still a significant gap between their understanding and the correct application of English grammar. In fact, Grammar has a significant impact on the writing skills of Vietnamese students in general, and especially the first-year students of English majors who were not much exposed to writing in high school, so they are not yet used to writing at a higher level. The majority of errors in their writings are due to the influence of their mother tongue and a lack of frequent practice and their misuse of word forms, as a matter of fact, the expected results have not been satisfactory. Based on the general insight into the writing competence of the freshmen, the study titled “An investigation into the common errors of word forms made in the writings of the freshmen: A case study” was done with the English-major students. A close survey was deliberately done with 142 paragraphs written by the first-year students to investigate the common errors of word forms made in their writings. From what was collected, the study subsequently offered some suggestions for helping the students improve their writing skills.  Article visualizations

Chemical diversity of essential oils of rhizomes of six species of Zingiberaceae family

In this study, the essential oils from the rhizomes of six species belonging to the Zingiberaceae family, including Zingiber zerumbet, Curcuma pierreana, Globba macrocarpa, Alpinia conchigera, Stahlianthus campanulatus and Amomum sp., collected in Binh Chau-Phuoc Buu Nature Reserve were isolated using hydrodistillation, and their constituents were identified via Gas Chromatography-Mass Spectrometry. A total of 91 constituents have been identified from essential oils. These compounds were classified into 4 clusters by Agglomerative Hierarchical Clustering (AHC) and Principal Component Analysis (PCA) analysis. The principal constituents of the essential oils isolated from four species, C. pierreana, S. campanulatus, A. conchigera, and Z. zerumbet contained camphene (18.82%), α-copaene (11.75%), p-xylene (21.86%), and α-santalene (17.91%), which were significantly different from those in previous reports. Furthermore, this study revealed the chemical constituents of essential oils of G. macrocarpa and Amomum sp. for the first time. Accordingly, artemisia triene (22.21%), β-pinene (13.57%), 4,6,8-trimethylazulene (11.1%), 2-tert-butylquinoline (9.86%), β-patchoulene (7.06%), α-elemene (6.93%), and β-ocimene (6.0%) were the major compounds in essential oils of G. macrocarpa rhizomes whereas the oil of Amomum sp. was found to be rich in 2-carene (21.82%), fenchyl acetate (14.26%), 3-carene (8.28%), bornyl acetate (7.7%), and D-limonene (7.13%)

Transmission of Japanese Encephalitis (JE) Virus in Gia Luong District, Ha Bac Province, Vietnam, After Je Vaccination, 1993-1994

A total of 15,183 children under 10 years old (37% of target population) was immunized with JE vaccine in Gia Luong District, Ha Bac Province, Vietnam, in 1993 to 1994. JE virus transmission was investigated by swine antibody survey and virus isolation from field mosquitoes. By the hemagglutination inhibition (HI) test, 73-90% of swine were antibody positive all year round, with high geometric mean titer (GMT) of 92.67-95.14 in May and June. By suckling mouse brain inoculation, 6 JE virus strains were isolated from Culex tritaeniorhynchus and Cx. vishuni, as well as laboratory reared F1 from field-caught Cx. tritaeniorhynchus. Serodiganosis by IgM-capture ELISA (MAC-ELISA) carried out on 60 of 85 clinical encephalitis cases detected 43 positives (71.66%). All these serologically confirmed JE cases had not been vaccinated. The results supported the vaccine efficacy to prevent overt JE