Pub Date : 2023-12-15DOI: 10.31276/vjste.65(4).101-109
Thuy Duong Pham, Thi Lan Anh Hoang, Thi Le Quyen Tran, T. T. Trinh
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.
{"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":"49 39","pages":""},"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}
Pub Date : 2023-12-15DOI: 10.31276/vjste.65(4).84-93
Nhan Ngo, Toi Vo, Lua Ngo
Lung diseases are the most common diseases worldwide, especially in Vietnam. Certain thoracic lung diseases can even lead to dangerous conditions for patients. X-ray are a useful imaging modality for detecting the abnormalities in the chest area. Furthermore, artificial intelligence can improve the detection of abnormalities in X-ray images, reduce misdiagnosis, close the knowledge gap between doctors, and alleviate the pressure on doctors. Therefore, this study aims to apply deep learning techniques to detect abnormalities in chest X-ray images and use data science and statistical approaches to improve the performance of the deep learning model. The data was explored and processed to obtain high quality data with optimal characteristics. We then applied data augmentation and optimization to the RetinaNet model with ResNet101 in a Feature Pyramid Network (FPN) backbone to achieve the best performance. Our model achieved mean average precision of 0.55 at a threshold of 0.5 (mAP@0.5) in a validation set, which included five diseases: aortic enlargement, cardiomegaly, interstitial lung disease, infiltration, and nodule/mass.
肺部疾病是世界上最常见的疾病，在越南尤其如此。某些胸腔肺部疾病甚至会给患者带来危险。X 射线是检测胸部异常的有效成像方式。此外，人工智能可以提高对 X 光图像异常的检测，减少误诊，缩小医生之间的知识差距，减轻医生的压力。因此，本研究旨在应用深度学习技术检测胸部 X 光图像中的异常情况，并利用数据科学和统计方法提高深度学习模型的性能。我们对数据进行了探索和处理，以获得具有最佳特征的高质量数据。然后，我们在特征金字塔网络（FPN）骨干中使用 ResNet101 对 RetinaNet 模型进行了数据增强和优化，以达到最佳性能。我们的模型在验证集中的平均精度达到了 0.55，阈值为 0.5 (mAP@0.5)，验证集包括五种疾病：主动脉扩大、心脏肿大、间质性肺病、浸润和结节/肿块。
{"title":"Application of deep learning in chest X-ray abnormality detection","authors":"Nhan Ngo, Toi Vo, Lua Ngo","doi":"10.31276/vjste.65(4).84-93","DOIUrl":"https://doi.org/10.31276/vjste.65(4).84-93","url":null,"abstract":"Lung diseases are the most common diseases worldwide, especially in Vietnam. Certain thoracic lung diseases can even lead to dangerous conditions for patients. X-ray are a useful imaging modality for detecting the abnormalities in the chest area. Furthermore, artificial intelligence can improve the detection of abnormalities in X-ray images, reduce misdiagnosis, close the knowledge gap between doctors, and alleviate the pressure on doctors. Therefore, this study aims to apply deep learning techniques to detect abnormalities in chest X-ray images and use data science and statistical approaches to improve the performance of the deep learning model. The data was explored and processed to obtain high quality data with optimal characteristics. We then applied data augmentation and optimization to the RetinaNet model with ResNet101 in a Feature Pyramid Network (FPN) backbone to achieve the best performance. Our model achieved mean average precision of 0.55 at a threshold of 0.5 (mAP@0.5) in a validation set, which included five diseases: aortic enlargement, cardiomegaly, interstitial lung disease, infiltration, and nodule/mass.","PeriodicalId":18650,"journal":{"name":"Ministry of Science and Technology, Vietnam","volume":"4 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138999820","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 : 2023-12-15DOI: 10.31276/vjste.65(4).11-13
Tuan H Ho
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.
{"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":"122 21","pages":""},"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}
Pub Date : 2023-12-15DOI: 10.31276/vjste.65(4).48-53
Thi Loan Pham, D. Trinh, Thi-Thu Nguyen, Trong Quang Do, P. Nguyen
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.
{"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":"25 11","pages":""},"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}
Pub Date : 2023-12-15DOI: 10.31276/vjste.65(4).71-76
Nhung T. Tuyet Hoang, Anh Thi-Kim Tran
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.
{"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":"54 5","pages":""},"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}
Pub Date : 2023-12-15DOI: 10.31276/vjste.65(4).54-61
Jasim Haider Hadi
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.
残余应力对环氧基涂料的特性和性能起着重要作用，其根源在于生产和应用过程中遇到的各种因素。本研究的重点是量化三种不同环氧基涂层（常用于原油储罐内衬）中的残余应力，这三种涂层分别是纯环氧基、Novolac 环氧基和玻璃片增强环氧基。我们采用 X 射线衍射法测量这些残余应力，并将其与通过有限元和人工神经网络方法获得的预测值进行比较。我们的研究结果表明，这三种环氧涂层在残余应力方面存在明显差异。具体来说，纯环氧涂层的残余应力较大，Novolac 环氧涂层的残余应力最小，而用玻璃片增强的涂层则介于两者之间。利用 FEM-ANN 模型模拟得出的结果与通过 X 射线方法获得的实验测量结果非常吻合。测试结果表明，与低温固化的涂层相比，高温固化的涂层具有较高的残余应力。将固化温度从 10 摄氏度提高到 50 摄氏度会使使用玻璃鳞片、Novolac 和纯环氧基涂层增强的涂层的残余应力分别增加 40.81%、11.085% 和 56.98%。
{"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":"335 9","pages":""},"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}
Pub Date : 2023-12-15DOI: 10.31276/vjste.65(4).94-100
Pham Thi Hai Mien, Dao Viet Ha, Cornelis Verduyn
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.
二十二碳六烯酸（DHA）在生物功能中发挥着关键作用，对人类和动物都有益。传统的 DHA 来源于鱼类和鱼油。由于这些来源存在海洋污染和成分不稳定等缺点，因此迫切需要探索其他可靠的 DHA 来源。Aurantiochytrium sp.已被确定为有望生产 DHA 的候选物质。本研究的主要目的是在以前公布的培养基中培养三种菌株，随后为 Aurantiochytrium sp.这些菌株在选定的培养基中生长，并测量细胞的干重。采用气相色谱法提取和分析总脂肪酸。在以葡萄糖为碳源、谷氨酸钠为氮源的培养基中，这三种菌株的生长情况均令人满意。菌株 B072 的 DHA 含量最高，峰值为 5.0 克/升，脂质累积率可达 57.57%（重量比）。生物质中的 DHA 含量为 21.43%（重量比），生物质产量为 23.35 克/升。维生素和微量元素对 Aurantiochytrium sp.的生长和 DHA 产量有积极影响。此外，菌株 B072 在生长和脂肪酸生产过程中有效利用了铵。
{"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":"122 1","pages":""},"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}
Pub Date : 2023-12-15DOI: 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
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.
在烧伤伤口的处理中，抗菌和伤口愈合性能至关重要。在这项研究中，我们制备了一种用于烧伤创面敷料的三层电纺聚（ε-己内酯）（PCL）膜。疏水性电纺 PCL 层中嵌入了银纳米粒子（SNPs）（PCL-Ag），并在其上涂覆了另一层等离子体处理过的电纺 PCL-Ag，以增强膜的润湿性。这种增强是为了促进敷料第三层--亲水性壳聚糖低聚物（COS）的吸收。对制备出的膜进行了表征和不同性能的测试，以证明其作为伤口敷料材料的适用性。由于壳聚糖的愈合能力和 SNP 的抗菌活性，制作出的膜结合了壳聚糖和 SNP，可支持愈合过程并降低烧伤的严重程度，同时不影响机械强度。我们进行了多项体外和体内实验，以评估其在烧伤伤口愈合方面的适用性。PCL-Ag/COS 样品表现出出色的体外生物相容性和对金黄色葡萄球菌菌株的抗菌活性。我们在实验室中使用这种膜治疗兔子的烧伤，历时 30 天，观察结果一致良好。这项研究为开发用于伤口愈合的生物活性敷料提供了启示，并为 COS 嵌入材料的实际应用提供了机会。
{"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":"72 1","pages":""},"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}
Pub Date : 2023-12-15DOI: 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
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.
{"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":"9 13","pages":""},"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}
Pub Date : 2023-12-15DOI: 10.31276/vjste.65(4).03-10
To Xuan Dinh, Nguyen Thi Thu Huong, Nguyen Ngoc Tuan, Nguyen Thanh Tien
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.
自主移动机器人（AMR）具有提高生产效率和降低劳动力成本的优势，其应用已逐渐成为智能工厂的关键。运动规划一直是 AMR 控制开发的关键部分。本文介绍了以燃料电池和电池混合动力为动力的全向轮式 AMR 的运动规划和位置跟踪控制系统。首先，介绍了 AMR 的运动学和动力学模型。导航系统由三个回路组成，第一回路是电机控制，第二回路是位置跟踪控制，还有一个运动规划层。用于反馈控制的 AMR 位置数据是通过将来自惯性测量单元（IMU）传感器、编码器传感器和测距传感器的数据与同步定位和映射（SLAM）算法进行传感器融合而获得的。然后进行运动规划，以获得距离最短、无碰撞的最佳运动路径。此外，还设计了跟踪算法，以驱动 AMR 遵循最优路径并实现高精度。实验结果表明，与传统方法和连续工作 8 小时相比，跟踪精度提高了 30%，在工业应用中大有可为，而且在精度和效率要求方面都取得了令人满意的结果。
{"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":"82 2","pages":""},"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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：