Ho Chi Minh City Open University Journal of Science Engineering and Technology最新文献

3D numerical investigation of functionally graded concrete 功能级配混凝土的三维数值研究

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2497.2023

Nguyen Ngoc Hau, Le Thanh Cuong

引用次数: 0

Minimal Spanning Tree application to determine market correlation structure 应用最小生成树确定市场关联结构

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2669.2023

B. T. Khoa, T. Huynh, Vo Dinh Nhat Truong, Le Vu Truong, Do Bui Xuan Cuong, Tran Khanh

{"title":"Minimal Spanning Tree application to determine market correlation structure","authors":"B. T. Khoa, T. Huynh, Vo Dinh Nhat Truong, Le Vu Truong, Do Bui Xuan Cuong, Tran Khanh","doi":"10.46223/hcmcoujs.tech.en.13.1.2669.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2669.2023","url":null,"abstract":"Determining the structure of market correlation is an important topic in theory and experiments. Under the impact of the Covid-19 pandemic, the market structure may be deformed. Therefore, this study examines the pandemic’s impact on the market structure. This study considered the correlation structure of the VN30 portfolio (including 30 stocks with the largest market capitalization); the collecting period is from July 28, 2000, to July 30, 2021. The data was divided into 02 phases before and after the pandemic. The Kruskal algorithm is implemented to determine the Minimal Spanning Tree (MST) structure to define the structure of market correlation. This study compared the change in the structure before and after the Covid-19 pandemic by structures’ mean of distances comparison. T-test results show that there are structural differences before and after the pandemic. Based on the research result, investors should change their risk management strategy to suit the market context because the previous structure has been changed.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91185908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The phylogenetic authentication of Ophiocordyceps sphecocephala from Lang Biang Biosphere Reserve, Lam Dong, Vietnam 越南林东朗比生物圈保护区球头蛇虫草的系统发育鉴定

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2641.2023

L. D. Thuan, P. T. Dinh, T. Hue, Vu Hoang Hai, N. Giảng, Trương Bình Nguyên, L. Thuy

{"title":"The phylogenetic authentication of Ophiocordyceps sphecocephala from Lang Biang Biosphere Reserve, Lam Dong, Vietnam","authors":"L. D. Thuan, P. T. Dinh, T. Hue, Vu Hoang Hai, N. Giảng, Trương Bình Nguyên, L. Thuy","doi":"10.46223/hcmcoujs.tech.en.13.1.2641.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2641.2023","url":null,"abstract":"During our expedition at Lang Biang Biosphere Reserve, samples of DL0023, parasitizing on wasps, were collected, then sent to the biology laboratory, Dalat University, Lam Dong Province, Vietnam, to preliminarily morphologically identify the name of this species as Ophiocordyceps sphecocephala. The method of Phenol (pH = 8)/Chloroform method was applied to isolated DNA. The PCR assays and sequencing were performed to amplify and sequencing ITS, nrLSU, and nrSSU, respectively. The phylogenetic methods of neighbor-joining, maximum likelihood, and maximum parsimony were constructed to identify the relationship between DL0023 and referent sequences. We successfully amplified and sequenced the target genes, and constructed concatenated data containing 29, 33, and 30 sequences of ITS, nrLSU and nrSSU, respectively, belonging to Clavicipitaceae clade A, clade B and clade C, and 02 sequences belonged to Glomerellaceae. The results of phylogenetic analysis shown that DL0023 was accepted at Ophiocordyceps and strongly formed the monophyletic group Ophiocordyceps sphecocephala with a high supported value. In conclusion, the concatenated dataset’s phylogenetic analyses effectively supported the identification of DL0023 as Ophiocordyceps sphecocephala.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81279811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The application based on google maps API to find and manage blood donation volunteers 该应用程序基于谷歌地图API来查找和管理献血志愿者

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2647.2023

N. H. Quang

引用次数: 0

Real-time PCR application in confirmation test of Salmonella Typhimurium on instant noodle 实时荧光定量PCR在方便面鼠伤寒沙门菌确证试验中的应用

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2479.2023

Alfi Sophian, S. Utaminingsih, Tirta Setya Bhakti, D. Rahmawati

{"title":"Real-time PCR application in confirmation test of Salmonella Typhimurium on instant noodle","authors":"Alfi Sophian, S. Utaminingsih, Tirta Setya Bhakti, D. Rahmawati","doi":"10.46223/hcmcoujs.tech.en.13.1.2479.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2479.2023","url":null,"abstract":"Real-Time PCR is a molecular biology testing instrument used for various types of food product testing applications to monitor the quality of a product. In addition, the real-time PCR technique can also be used to test the detection of pathogenic bacteria in some foods and processed products. The purpose of this study was to detect Salmonella typhimurium using real-time PCR. This research can be a source of information and a reference for similar research. The test method used is the real-time PCR method with the green SYBR kit. Data analysis was carried out by looking at the results of interpreting Ct values and Tm values. Positive results are indicated by the formation of the Ct curve and the Tm curve. From the research conducted, it was found that the Ct value was in the range of 11.90 - 12.10 with an average of 12.02, while the Tm value was in the range of 85.10 - 85.20 with an average of 85.15. From the study results, it can be concluded that the use of real-time PCR for testing the detection of Salmonella typhimurium in instant noodle products can be applied.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82400891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Isolation and identification of Vibrio spp. with potential ability to produce polysaccharide monooxygenase from diseased Penaeus monodon 从患病的单对虾中产生多糖单加氧酶的弧菌的分离与鉴定

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2645.2023

Ho Ta Giap, N. Vu, V. V. Van

{"title":"Isolation and identification of Vibrio spp. with potential ability to produce polysaccharide monooxygenase from diseased Penaeus monodon","authors":"Ho Ta Giap, N. Vu, V. V. Van","doi":"10.46223/hcmcoujs.tech.en.13.1.2645.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2645.2023","url":null,"abstract":"Polysaccharide monooxygenases (PMOs) and Glycoside Hydrolases (GH) play a crucial role in breaking down chitin and cellulose. Research on PMOs has mainly focused on their role in the production of bioethanol from biomass. Still, the potential of PMOs as virulence factors in microorganisms is not been fully studied. Some pathogenic bacteria secrete PMOs, which have been identified as virulence factors. The ability of Vibrio species to metabolize chitin is well-known, but the question of which Vibrio species contains the PMO gene remains unanswered. Materials and methods: Black tiger shrimp Penaeus monodon was collected from a culture pond in Long An, Vietnam. Thiosulfate-citrate-bile salts-sucrose and CHROMagar Vibrio agar were used to isolate, Vibrio bacteria from the shrimp samples. Mixed bases primers were designed to detect PMOs gene from Vibrio strains. Results: Total of 35 different strains of bacteria were isolated from the guts and pancreas of the shrimp sample. Based on biochemical tests, there were a total of 20 different Vibrio strains identified among 35 isolated strains. The PCR results showed that six isolates could have the PMOs gene. The partial 16S rDNA fragments of six isolate Vibrio strains were sequenced. Comparing 16S rDNA sequences with sequences available in NCBI databases revealed that all the sequences are Vibrio spp. 16S rDNA sequences.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"110 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80548697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Load-carrying capacity of circular concrete filled steel tubes under axial loading: Reliability analyses 轴向荷载作用下圆形钢管混凝土承载能力可靠性分析

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2549.2023

Cao Van Vui, Nguyen Hong An, Bui Van Ho

{"title":"Load-carrying capacity of circular concrete filled steel tubes under axial loading: Reliability analyses","authors":"Cao Van Vui, Nguyen Hong An, Bui Van Ho","doi":"10.46223/hcmcoujs.tech.en.13.1.2549.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2549.2023","url":null,"abstract":"This paper presents the results of reliability analyses of load-carrying capacity of circular concrete filled steel tubes (CFST) using different codes. Four parameters that govern the load-carrying capacity of CFST were considered as variables. These variables include the yield strength of steel, the strength of concrete, the diameter of CFST, and the thickness of the steel tube. The Monte Carlo technique was used for the simulation. Simulations were conducted, and the obtained load-carrying capacities were analysed. The results indicated that the load-carrying capacity of circular CFST follows a normal distribution. Eurocode 4 provided the highest mean load-carrying capacity because the confinement effect was taken into consideration, whereas the mean load-carrying capacity obtained from the American Institute of Steel Construction (2016) and Architectural Institute of Japan (AIJ, 2008) codes were similar. All considered variables resulted in higher standard deviations and coefficients of variation, while the thickness of the steel tube resulted in the lowest standard deviation and coefficients of variation. Therefore, the reliability indices obtained from all considered variables are lowest while those obtained from the variable of thickness are highest.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76983809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Disinfection of methicillin-resistant Staphylococcus Aureus on flat surface by 460 nm light and hydrogen peroxide combination 460 nm光与双氧水联合消毒平面耐甲氧西林金黄色葡萄球菌

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2023-04-05 DOI: 10.46223/hcmcoujs.tech.en.13.1.2649.2023

Truong Nguyen Thuan Thien, N. Vu, T. Tin, V. V. Van, Nguyen Thi Thu Hoai, Vu Minh Thiet

{"title":"Disinfection of methicillin-resistant Staphylococcus Aureus on flat surface by 460 nm light and hydrogen peroxide combination","authors":"Truong Nguyen Thuan Thien, N. Vu, T. Tin, V. V. Van, Nguyen Thi Thu Hoai, Vu Minh Thiet","doi":"10.46223/hcmcoujs.tech.en.13.1.2649.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2649.2023","url":null,"abstract":"Staphyloxanthin (STX) is a carotenoid pigment produced by Staphylococcus aureus to protect the bacteria from oxidation stress. Eliminating Staphyloxanthin from S. aureus cell membrane by inducing the pigment photolysis using 460nm light, then killing weakened bacteria with an H2O2 solution could be a new approach to develop anti - Staphylococcus aureus procedure. A model to prove the feasibility of this combination to kill Methicillin-Resistant Staphylococcus Aureus (MRSA) bacteria on a flat surface was tested. Material and method: Staphyloxanthin pigment extracted from MRSA bacteria was treated with 460nm light at different light intensities to evaluate the photolysis potential of 460nm light. The change in MRSA shape after 460nm light treatment was also investigated by Scanning electron microscopy. Using glass cover-slips as an emulated model for contact surface in public, the combination of different 460nm light intensities and H2O2 0.75% was tested on the surface loaded with MRSA living cells, and the number of MRSA cells survived after treatment was enumerated. Result: Higher intensity and longer light treatment yielded a higher photolysis effect, as 100 and 200 mW/cm2 light intensity could degrade 77.50% to 83.45% of STX pigment after 20 minutes of irradiation. Also, MRSA cells had significant changes as more wrinkles and bumps appeared under high-intensity 460nm light. When tested on the flat surface of the coverslip, the strongest MRSA eradication effect can be observed in the combination of 200 mW/cm2 light treatment with 0.75% H2O2 solution, as 100% MRSA cells were completely killed after 20 minutes of treatment.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72954460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Isolation and characterization of Rhizobium spp. and Bradyrhizobium spp. from legume nodules 豆科根瘤中根瘤菌和缓生根瘤菌的分离与鉴定

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2022-11-04 DOI: 10.46223/hcmcoujs.tech.en.12.2.2116.2022

Nguyen Ngọc Tung, Vo Thi Thu Thao, Nguyen Thi Minh Khanh, Pham Cam Duyen, Phung Thi Tram, Doan Thi Minh Thu, Le Thi Bich Thao, Nguyen Ngoc Anh Vy, Ta Nguyen Minh Phuong, Tran Thi Kim Xinh, Nguyen Minh Quan, Nguyen Tan Duc

{"title":"Isolation and characterization of Rhizobium spp. and Bradyrhizobium spp. from legume nodules","authors":"Nguyen Ngọc Tung, Vo Thi Thu Thao, Nguyen Thi Minh Khanh, Pham Cam Duyen, Phung Thi Tram, Doan Thi Minh Thu, Le Thi Bich Thao, Nguyen Ngoc Anh Vy, Ta Nguyen Minh Phuong, Tran Thi Kim Xinh, Nguyen Minh Quan, Nguyen Tan Duc","doi":"10.46223/hcmcoujs.tech.en.12.2.2116.2022","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.12.2.2116.2022","url":null,"abstract":"Rhizobia topic has been re-focused in recent years because of new findings on their traits not only as nitrogen-fixing bacteria but also as plant growth-promoting rhizobacteria. When combing rhizobial strains with novel biological carriers (e.g., biochar) for inoculant production, it brings great potential for improving soil health in long-term. Appreciating this trend, this study is designed to isolate and characterize local rhizobial strains from legume fields using the conventional method with some modifications to increase efficiency in rhizobial identification. As a result, 17 rhizobial strains were isolated and classified biochemically that genetic identification outcome confirmed 10 strains belong to 07 different Rhizobium species as R. mayense, R. paknamense, R. pusense, R. miluonense, R. tropici, R. phaseoli, and R. multihospitium while the rest belong to 06 various Bradyrhizobium species as B. elkanii, B. centrosematis, B. guangxiense, B. liaoningense, B. yuanmingense, and B. arachidis. Thermal and saline tolerant tests together with seed germination tests also performed on these rhizobial strains to gain data on their responses to abiotic stresses. By comparing rice and mung bean GI values, we can assess the effectiveness of each rhizobial strains to help seeds at their early germination.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73491534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A multi locus sequence analysis scheme for phylogeny of the Bacillus subtilis species complex and its advantages over 16S rRNA genes 枯草芽孢杆菌物种复合体系统发育的多位点序列分析方案及其相对于16S rRNA基因的优势

Ho Chi Minh City Open University Journal of Science Engineering and Technology Pub Date : 2022-11-04 DOI: 10.46223/hcmcoujs.tech.en.12.2.2255.2022

Dao Nu Dieu Hong, Trang Hoang Long, N. T. Tiên, Dinh Anh Hoa, T. Phan, Le Thi Huynh Tram

引用次数: 1