Pub Date : 2023-04-05DOI: 10.46223/hcmcoujs.tech.en.13.1.2497.2023
Nguyen Ngoc Hau, Le Thanh Cuong
In the design of engineering structures, concrete is assumed to have homogeneously mechanical properties. However, in reality, the concrete material is usually not uniform with respect to the height of structures because segregation mostly occurs during construction. The higher density is presented at, the lower part of the structure due to a higher proportion of aggregate and vice versa. Moreover, the disparity of creep, shrinkage, hydration heat, and curing method also leads to the difference in the quality of concrete. Therefore, it is necessary to study the responses of a concrete element with various mechanical properties. In this study, the functional elastic modulus of concrete material (FGC) is investigated numerically for its effects on the static responses of the element under axial compression. Conventional Finite Element Method (FEM) and Meshless method are used to model the structure. The reliability of the numerical model is validated by comparing the obtained results with experimental data.
{"title":"3D numerical investigation of functionally graded concrete","authors":"Nguyen Ngoc Hau, Le Thanh Cuong","doi":"10.46223/hcmcoujs.tech.en.13.1.2497.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2497.2023","url":null,"abstract":"In the design of engineering structures, concrete is assumed to have homogeneously mechanical properties. However, in reality, the concrete material is usually not uniform with respect to the height of structures because segregation mostly occurs during construction. The higher density is presented at, the lower part of the structure due to a higher proportion of aggregate and vice versa. Moreover, the disparity of creep, shrinkage, hydration heat, and curing method also leads to the difference in the quality of concrete. Therefore, it is necessary to study the responses of a concrete element with various mechanical properties. In this study, the functional elastic modulus of concrete material (FGC) is investigated numerically for its effects on the static responses of the element under axial compression. Conventional Finite Element Method (FEM) and Meshless method are used to model the structure. The reliability of the numerical model is validated by comparing the obtained results with experimental data.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82794059","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}
Pub Date : 2023-04-05DOI: 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
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.
{"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}
Pub Date : 2023-04-05DOI: 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
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.
{"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}
Pub Date : 2023-04-05DOI: 10.46223/hcmcoujs.tech.en.13.1.2647.2023
N. H. Quang
Most young Vietnamese people now have access to the movement of voluntary blood donation. Volunteers who want to donate blood must meet certain health requirements and wait at least three months between donations. As a result, the blood received falls below the bare minimum, resulting in reserve anemia. Based on these practical requirements, the article proposes a tool to assist health facilities in locating people willing to donate blood in hazardous situations within a reasonable distance. This system is built on a three-layer model that interacts with the database via Entity Framework and uses the Google Map API to locate blood donors. Before being used, the application was tested on a website using blood donation data from volunteers in the Binh Thanh and Go Vap districts.
{"title":"The application based on google maps API to find and manage blood donation volunteers","authors":"N. H. Quang","doi":"10.46223/hcmcoujs.tech.en.13.1.2647.2023","DOIUrl":"https://doi.org/10.46223/hcmcoujs.tech.en.13.1.2647.2023","url":null,"abstract":"Most young Vietnamese people now have access to the movement of voluntary blood donation. Volunteers who want to donate blood must meet certain health requirements and wait at least three months between donations. As a result, the blood received falls below the bare minimum, resulting in reserve anemia. Based on these practical requirements, the article proposes a tool to assist health facilities in locating people willing to donate blood in hazardous situations within a reasonable distance. This system is built on a three-layer model that interacts with the database via Entity Framework and uses the Google Map API to locate blood donors. Before being used, the application was tested on a website using blood donation data from volunteers in the Binh Thanh and Go Vap districts.","PeriodicalId":34742,"journal":{"name":"Ho Chi Minh City Open University Journal of Science Engineering and Technology","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87844029","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}
Pub Date : 2023-04-05DOI: 10.46223/hcmcoujs.tech.en.13.1.2479.2023
Alfi Sophian, S. Utaminingsih, Tirta Setya Bhakti, D. Rahmawati
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.
{"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}
Pub Date : 2023-04-05DOI: 10.46223/hcmcoujs.tech.en.13.1.2645.2023
Ho Ta Giap, N. Vu, V. V. Van
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.
{"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}
Pub Date : 2023-04-05DOI: 10.46223/hcmcoujs.tech.en.13.1.2549.2023
Cao Van Vui, Nguyen Hong An, Bui Van Ho
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.
{"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}
Pub Date : 2023-04-05DOI: 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
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.
{"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}
Pub Date : 2022-11-04DOI: 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
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.
{"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}
Pub Date : 2022-11-04DOI: 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
A multi locus sequence analysis (MLSA approach) was studied on the Bacillus genus, or the Bacillus subtilis species complex for specific, including 08 strains from four species (B. subtilis, B. pumilus, B. licheniformis and B. amyloliquefaciens) were provided by Biotechnology Center of Ho Chi Minh City. The research was based on sequences of 16S rRNA genes, the concatenation of five protein-coding housekeeping genes: glpF, pta, purH, pycA, and rpoD. After PCR amplification and sequencing the phylogenetic tree of 16S rRNA sequences, concatenate sequences (as well as the phylogenetic tree of each housekeeping gene) are constructed for comparison and discussion. The aim of this study is reach for better resolution and differentiation of strains and species within the B. subtilis species and to determine whether MLSA scheme show advantages in 16S rRNA gene-based studies.
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