Ministry of Science and Technology, Vietnam最新文献_第9页

Isolation of Weizmannia coagulansand probiotic characterisation of strains 分离凝结地衣芽孢杆菌并确定菌株的益生特性

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).101-109

Thuy Duong Pham, Thi Lan Anh Hoang, Thi Le Quyen Tran, T. T. Trinh

{"title":"Isolation of Weizmannia coagulansand probiotic characterisation of strains","authors":"Thuy Duong Pham, Thi Lan Anh Hoang, Thi Le Quyen Tran, T. T. Trinh","doi":"10.31276/vjste.65(4).101-109","DOIUrl":"https://doi.org/10.31276/vjste.65(4).101-109","url":null,"abstract":"Weizmannia coagulans is a potential bacterial candidate for probiotics because of their advantageous characteristics in endospore formation, antibacterial production, and other beneficial human health effects. In this study, we isolated W. coagulans strains from different sample types collected in Hanoi and examined them for probiotic characteristics. From 40 samples, 5 strains were isolated from cow faeces. All W. coagulans strains had non-haemolytic activity and were susceptible to seven tested antibiotics. Cell-free supernatants of W. coagulans strains cultured in MRS medium could inhibit some bacterial pathogens such as Enterococcus faecalis, Listeria monocytogenes, Vibrio vulnificus, and Aeromonas dhakensis. The strains showed antioxidant activity with scavenging DPPH rates ranging from 72 to 82%. Three strains were able to adhere to the HT-29 cell line with adhesion ratesranging from 46 to 62.59%. The spores and vegetative cells of the three strains also showed great stress tolerance (survival rates >90%) against simulated gastrointestinal fluid. In liquid media containing 0.1% pancreatin and 0.3% bile salt, spores of VTCC 12782 and VTCC 12779 could germinate at rates of 25 and 2%, respectively. With the most beneficial characteristics, W. coagulans VTCC 12782 is suggested as a potential candidate for the development of probiotic products in the future.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138995879","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

Application of deep learning in chest X-ray abnormality detection 深度学习在胸部 X 光异常检测中的应用

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).84-93

Nhan Ngo, Toi Vo, Lua Ngo

引用次数: 0

Iron(III) promoted oxidative annulation of benzylic C-H bonds in (α-amino)arylacetic acids for synthesis of 4-aryl pyrrolo[1,2-a]quinoxalines 铁(III)促进(α-氨基)芳基乙酸中苄基 C-H 键的氧化环化以合成 4-芳基吡咯并[1,2-a]喹喔啉类化合物

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).11-13

Tuan H Ho

{"title":"Iron(III) promoted oxidative annulation of benzylic C-H bonds in (α-amino)arylacetic acids for synthesis of 4-aryl pyrrolo[1,2-a]quinoxalines","authors":"Tuan H Ho","doi":"10.31276/vjste.65(4).11-13","DOIUrl":"https://doi.org/10.31276/vjste.65(4).11-13","url":null,"abstract":"Using amino acids for synthesis of heterocycles is a synthetically promising field. However, developing the practical methods for transformations of amino acids into heterocycles is still challenging. Given that alpha amino acids are abundant or easily prepared, herein we report a method for annulation of benzylic C-H bonds in derivatives of 2-phenylglycine with 1-(2-nitroaryl)pyrroles. The reactions proceeded well in the presence of iron(III) acetylacetonate catalyst and potassium carbonate base. Scope of pyrrolo[1,2-a]quinoxalines was studied. Regardless of electronic properties of substituents, the pyrrolo[1,2-a]quinoxaline de-rivatives were successfully isolated, as yields varied from 42% to 52%. Pyrrolo[1,2-a]quinoxalines substituted with heterocycles at C4 positions as pyridine and thiophene were competent substrates. Reaction mechanism was proposed to start with a decar-boxylative/deaminative sequence of 2-phenylglycine to afford benzaldehyde. The iron catalyst was presumed to facilitate the re-duction of 1-(2-nitroaryl)pyrroles to furnish the corresponding aniline. Imine condensation followed by cyclisation and oxidation would yield the pyrrolo[1,2-a]quinoxaline. Our method would offer a convenient tactic to transform abundant alpha amino acids into synthetically useful heterocycles.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138999671","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

Study on flexural behaviour of printed concrete wide beams using polypropylene fibres 使用聚丙烯纤维的印花混凝土宽梁抗弯行为研究

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).48-53

Thi Loan Pham, D. Trinh, Thi-Thu Nguyen, Trong Quang Do, P. Nguyen

{"title":"Study on flexural behaviour of printed concrete wide beams using polypropylene fibres","authors":"Thi Loan Pham, D. Trinh, Thi-Thu Nguyen, Trong Quang Do, P. Nguyen","doi":"10.31276/vjste.65(4).48-53","DOIUrl":"https://doi.org/10.31276/vjste.65(4).48-53","url":null,"abstract":"Sustainability in building construction is an inevitable aspect of future construction projects. The justification of sustainability is highly appreciated by comparing 3D concrete printing technology with conventional construction. However, the 3D printing concrete system has limitations and challenges in industrial applications. The reason is that this process was initially used in small non-structural applications and is now being adopted for large-scale structures. Thanks to concrete printing machines, a wide variety of web frames are also available - something completely impossible to achieve using traditional formwork for pouring concrete. In this study, the girder web is designed in the style of truss beams. Three wide beams with different amounts of polypropylene (PP) fibre were printed, and 3-point loading tests were conducted. The failure mode, load-bearing capacity, and deflection were reported in this study. According to the results, applying concrete printing technology in civil and industrial construction is entirely feasible. The printing process successfully produced models with a nozzle diameter of 22 mm and layer height of 10 mm, ensuring sufficient adhesion force between the printing layers. Using a PP fibre content of about 0.25% yielded the best results in terms of concrete compressive strength and beams’ flexural strength, while a PP fibre content of about 1.00% tended to increase the ductility of the member. Although the failure mode is brittle, the beams exhibited deflection before fracture far beyond the allowable deflection value of a flexural member. Therefore, the application of printed components to construction is feasible.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996067","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

Biodegradable containers from rice husk as substitutes for single-use plastic products 用稻壳制成的可生物降解容器替代一次性塑料制品

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).71-76

Nhung T. Tuyet Hoang, Anh Thi-Kim Tran

{"title":"Biodegradable containers from rice husk as substitutes for single-use plastic products","authors":"Nhung T. Tuyet Hoang, Anh Thi-Kim Tran","doi":"10.31276/vjste.65(4).71-76","DOIUrl":"https://doi.org/10.31276/vjste.65(4).71-76","url":null,"abstract":"Vietnam ranks among the top four nations for single-use plastic (SUP) waste, trailing only China, Indonesia, and Philippines. The abundant rice husk (RH) by-product of rice cultivation presents an opportunity to fabricate biodegradable containers, potentially supplanting single-use disposables. This study focuses on creating biodegradable containers from RH via thermo-pressing. Utilising the Taguchi orthogonal array method, we examined the impact of the RH to modified starch (MS) ratio (w/w %), pressing temperature (°C), and time (minutes) on the trays’ hardness, colour variation, and density, aiming to refine the manufacturing process. Additionally, variations in adhesive concentrations and glycerol were assessed for their influence on the aforementioned properties. The identified optimal conditions for fabricating viable biodegradable containers were a RH and MS composition of 80% (w/w), with a pressing duration of 3 minutes at 150°C. The resulting product exhibited a hardness of 5.26±0.22 kgF. Moreover, the thickness, density, and colour on the front and back sides were measured at 2.05±0.01 mm, 0.97±0.004 g/cm³, 50.87±0.96, and 48.05±0.87, respectively. Consequently, RH-based materials have emerged as promising candidates for crafting consumer-safe, environmentally benign biodegradable containers.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996365","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

Investigation of residual stress in epoxy-based coatings using X-ray and FEM-ANN techniques 利用 X 射线和 FEM-ANN 技术研究环氧基涂层中的残余应力

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).54-61

Jasim Haider Hadi

{"title":"Investigation of residual stress in epoxy-based coatings using X-ray and FEM-ANN techniques","authors":"Jasim Haider Hadi","doi":"10.31276/vjste.65(4).54-61","DOIUrl":"https://doi.org/10.31276/vjste.65(4).54-61","url":null,"abstract":"Residual stresses play a significant role in the properties and performance of epoxy-based coatings, with their origins rooted in various factors encountered during production and application. This study focuses on quantifying residual stresses in three distinct epoxy-based coatings, commonly used as linings for crude oil storage tanks, namely, pure epoxy, Novolac epoxy, and glass-flake-reinforced epoxy. We employ X-ray diffraction to measure these residual stresses and compare them against predicted values obtained through finite element and artificial neural network methods. Our findings reveal notable differences in residual stresses among the three types of epoxy coatings. Specifically, pure epoxy coatings exhibit higher residual stresses, Novolac epoxy coatings display the lowest, and those reinforced with glass flakes fall in between. Utilising the FEM-ANN model for simulations yields results that closely align with experimental measurements obtained via the X-ray method. Test results demonstrate that the coatings cured at high temperatures have high residual stresses compared to those cured at lower temperatures. Increasing the curing temperature from 10 to 50oC will increase residual stresses by 40.81, 11.085, and 56.98% for coatings reinforced with glass-flake, Novolac, and pure epoxy-based coating, respectively.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996645","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

Nutritional effects on biomass and metabolic products by Aurantiochytrium sp. 营养对 Aurantiochytrium sp.

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).94-100

Pham Thi Hai Mien, Dao Viet Ha, Cornelis Verduyn

{"title":"Nutritional effects on biomass and metabolic products by Aurantiochytrium sp.","authors":"Pham Thi Hai Mien, Dao Viet Ha, Cornelis Verduyn","doi":"10.31276/vjste.65(4).94-100","DOIUrl":"https://doi.org/10.31276/vjste.65(4).94-100","url":null,"abstract":"Docosahexaenoic acid, or Docosahexaenoic acid (DHA), plays a pivotal role in biological functions and is beneficial for both humans and animals. Traditionally, DHA is sourced from fish and fish oil. Due to the disadvantages associated with these sources, such as marine pollution and variable composition, there is a pressing need to explore alternative, reliable sources for DHA. Aurantiochytrium sp. has been identified as a promising candidate for DHA production. The primary aim of this study was to cultivate three strains in previously published media and, subsequently, to develop defined or semi-defined media for Aurantiochytrium sp.. These strains were grown in the selected media, and the dry weight of the cells was measured. Total fatty acids were extracted and analysed using gas chromatography. All three strains demonstrated satisfactory growth in media that incorporated glucose as a carbon source and monosodium glutamate as a nitrogen source. Strain B072 achieved the highest DHA concentration, with a peak of 5.0 g/l, and could accumulate lipids up to 57.57% (w/w). The DHA content in the biomass was 21.43% (w/w), with a biomass yield of 23.35 g/l. Vitamins and trace elements positively influenced the growth and DHA production of Aurantiochytrium sp.. Furthermore, strain B072 efficiently utilised ammonium for growth and fatty acid production.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138997513","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

Chitosan oligomer/silver nanoparticles/PCL composite electrospun membrane for severe burn wound healing 壳聚糖低聚物/银纳米粒子/PCL 复合电纺丝膜用于严重烧伤创面愈合

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).62-70

Anh Mai Que, Tuan Ngan Tang, Tam Phan Thi Thanh, Thanh Tu Duong, Thanh Binh Vu, Van Khiem Nguyen, Hoan Ngoc Doan, Hiep Thi Nguyen

{"title":"Chitosan oligomer/silver nanoparticles/PCL composite electrospun membrane for severe burn wound healing","authors":"Anh Mai Que, Tuan Ngan Tang, Tam Phan Thi Thanh, Thanh Tu Duong, Thanh Binh Vu, Van Khiem Nguyen, Hoan Ngoc Doan, Hiep Thi Nguyen","doi":"10.31276/vjste.65(4).62-70","DOIUrl":"https://doi.org/10.31276/vjste.65(4).62-70","url":null,"abstract":"In the management of burn wounds, antimicrobial and wound healing properties are crucial. In this study, we prepared a three-layer electrospun poly(ε-caprolactone) (PCL) membrane for burn wound dressing. The hydrophobic electrospun PCL layer, embedded with silver nanoparticles (SNPs) (PCL-Ag), was coated with another layer of electrospun plasma-treated PCL-Ag to enhance the wettability of the membrane. This enhancement was to facilitate the absorption of the hydrophilic chitosan oligomer (COS) - the third layer of the dressing. The resultant membranes were characterised and tested for different properties to demonstrate their applicability as wound dressing materials. The combination of COS and SNPs of the fabricated membrane supports the healing process and reduces burn severity due to the healing capacity of COS and the antibacterial activity of SNPs, without compromising mechanical strength. We conducted several in vitro and in vivo experiments to evaluate its applicability for burn wound healing. The PCL-Ag/COS sample demonstrated outstanding in vitro biocompatibility and excellent antibacterial activity against Staphylococcus aureus strains. We used the membrane to treat burns on rabbits in the laboratory over 30 days, and consistently observed positive outcomes. This research offers insights into the development of bioactive dressings for wound healing and opens up opportunities for practical applications of COS-incorporated materials.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138998070","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

Electrochemical synthesis of conjugated copolymer poly(3-hexylthiophene-co-dithenopyrrole): Stepwise approach to enhance electro-optical properties 共轭共聚物聚(3-己基噻吩-共二苯基吡咯)的电化学合成：逐步提高电光特性的方法

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).29-35

Thao Phuong Le Nguyen, Cam Hong Thi Nguyen, T. H. Luu, T. Truong, B. Doan, T. Nguyen, H. T. Nguyen

{"title":"Electrochemical synthesis of conjugated copolymer poly(3-hexylthiophene-co-dithenopyrrole): Stepwise approach to enhance electro-optical properties","authors":"Thao Phuong Le Nguyen, Cam Hong Thi Nguyen, T. H. Luu, T. Truong, B. Doan, T. Nguyen, H. T. Nguyen","doi":"10.31276/vjste.65(4).29-35","DOIUrl":"https://doi.org/10.31276/vjste.65(4).29-35","url":null,"abstract":"Electrochemical polymerisation of 3-hexylthiophene (3HT) and electrochemical copolymerisation of 3HT and N-benzoyl dithienopyrrole (BDP) were performed to prepare polymer and copolymer films using a linear sweep voltammetry potentiostatic technique with a voltage range from 1.7-1.8 V and a scan rate of 0.1 mV/s. Cyclic voltammetry (CV) curves, Fourier-transform infrared (FTIR) spectra, scanning electron microscope (SEM) images, and UV-Vis absorption spectra of the polymer and copolymer were recorded for analysis and comparison of the electropolymerisation process and properties of the resultant films. The SEM photographs of the copolymer base on 3HT and BDP exhibited a rigid structure with large spherical aggregates with an average size around 200 nm. The copolymer of 3HT and BDP exhibited the band gaps of 2.25 eV which was determined via electrochemical measurement that is higher than of band gaps of homopolymer poly(3-hexylthiophene) (P3HT). The copolymer’s energy bandgap HOMO-LUMO was enhanced compared to polymer P3HT. Moreover, the increased conjugation length significantly improved the morphology structure as well as the electrochemical stability of the conjugated copolymer.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138970642","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

Motion planning and control of an autonomous mobile robot 自主移动机器人的运动规划与控制

Ministry of Science and Technology, Vietnam Pub Date : 2023-12-15 DOI: 10.31276/vjste.65(4).03-10

To Xuan Dinh, Nguyen Thi Thu Huong, Nguyen Ngoc Tuan, Nguyen Thanh Tien

{"title":"Motion planning and control of an autonomous mobile robot","authors":"To Xuan Dinh, Nguyen Thi Thu Huong, Nguyen Ngoc Tuan, Nguyen Thanh Tien","doi":"10.31276/vjste.65(4).03-10","DOIUrl":"https://doi.org/10.31276/vjste.65(4).03-10","url":null,"abstract":"The application of autonomous mobile robots (AMRs) has gradually become crucial in smart factories due to the advantages of improving production efficiency and reducing labour costs. Motion planning has been a key part of AMR control development. This paper presents motion planning and position tracking control systems of an omnidirectional wheel AMR powered by a hybrid fuel cell and battery power source. First, the kinematical and dynamic models of the AMR are introduced. The navigation system comprises three loops, with the first loop being motor control, the second loop being position tracking control, and a motion planning layer. The position data of the AMR for feedback control is obtained through sensor fusion of data from the inertial measurement unit (IMU) sensor, encoder sensor, and ranging sensor with simultaneous localisation and mapping (SLAM) algorithm. The motion planning is then applied to obtain an optimal path with the shortest distance and collision-free movement. In addition, the tracking algorithm is designed to drive the AMR to follow the optimal path and achieve high accuracy. The experimental results show a 30% improvement in tracking accuracy compared to traditional approaches and 8 hours of continuous working, which is promising for industrial applications, and the results are satisfactory in terms of both accuracy and efficiency requirements.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138996280","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