Treatment of wastewater from super-intensive shrimp farming (SISF) for discharge or recirculation purposes is currently attracting the attention of managers and researchers. The fixed bed biofilm reactor (FBBR) has been successfully used for biological treatment of drinking water as well as for wastewater treatment in aquaculture farm. Ammonium and salinity are important factors affecting the efficiency of pollutants treatment. This paper presents the results of research on ammonium treatment in super-intensive shrimp wastewater by aerobic microbiological process using FBBRs. The results showed that at ammonium loading rates of 0.014; 0.028; 0.049 and 0.070 kg/m3/d, at salinity of 10‰, the ammonium removal efficiencies were 98 - 99; 97.7 - 98.8; 96.8 – 98.7 and 95.7 – 98.0 percent respectively (ammonium concentrations in effluent were 0.05 – 0.1; 0.12 – 0.23; 0.23 – 0.56 and 0.51 – 1.07 mgN/l, respectively), at salinity of 15‰, the ammonium removal efficiencies were 95.8-96.0, 94.5-92.0, 93.1-92.3 and 66.8-68.8 percent respectively (ammonium in effluent were 0.20 – 0.21; 0.55 – 0.8; 1.20 – 1.35 and 7.8 – 8.3 mgN/l, respectively), at salinity of 20‰, the ammonium removal efficiencies were 92.0-96.0, 87.0-89.0, 69.1-70.9 and 59.6-66.0 percent respectively (ammonium in effluent were 0.2 – 0.4; 1.1 – 1.3; 5.1 – 5.4 and 8.5 – 10.1 mgN/l, respectively). This result showed that the influence of ammonium loading and salinity on ammonium treatment efficiency was very significant.
{"title":"The effects of ammonium loading rates and salinity on ammonium treatment of wastewater from super-intensive shrimp farming","authors":"Tran Manh, Nguyen Thanh, Tung, Nguyen Trieu Duong, Nguyen Cam Tu, Nguyen Truong Quan, Nguyen Hoai Chau","doi":"10.15625/2525-2518/16427","DOIUrl":"https://doi.org/10.15625/2525-2518/16427","url":null,"abstract":"Treatment of wastewater from super-intensive shrimp farming (SISF) for discharge or recirculation purposes is currently attracting the attention of managers and researchers. The fixed bed biofilm reactor (FBBR) has been successfully used for biological treatment of drinking water as well as for wastewater treatment in aquaculture farm. Ammonium and salinity are important factors affecting the efficiency of pollutants treatment. This paper presents the results of research on ammonium treatment in super-intensive shrimp wastewater by aerobic microbiological process using FBBRs. The results showed that at ammonium loading rates of 0.014; 0.028; 0.049 and 0.070 kg/m3/d, at salinity of 10‰, the ammonium removal efficiencies were 98 - 99; 97.7 - 98.8; 96.8 – 98.7 and 95.7 – 98.0 percent respectively (ammonium concentrations in effluent were 0.05 – 0.1; 0.12 – 0.23; 0.23 – 0.56 and 0.51 – 1.07 mgN/l, respectively), at salinity of 15‰, the ammonium removal efficiencies were 95.8-96.0, 94.5-92.0, 93.1-92.3 and 66.8-68.8 percent respectively (ammonium in effluent were 0.20 – 0.21; 0.55 – 0.8; 1.20 – 1.35 and 7.8 – 8.3 mgN/l, respectively), at salinity of 20‰, the ammonium removal efficiencies were 92.0-96.0, 87.0-89.0, 69.1-70.9 and 59.6-66.0 percent respectively (ammonium in effluent were 0.2 – 0.4; 1.1 – 1.3; 5.1 – 5.4 and 8.5 – 10.1 mgN/l, respectively). This result showed that the influence of ammonium loading and salinity on ammonium treatment efficiency was very significant.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"234 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139316105","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 : 2023-10-20DOI: 10.15625/2525-2518/18079
Pannirselvam N, Sudarsan J S, Nithiyanantham S
(FRP) plays a major role in the strengthening of existing structures due to the age of the structure or natural calamities like earthquakes, floods, cyclones, etc. For reducing the size of structural members, the FRP wrapping assists to achieve the performance of the structure. Concrete is widely used due to its advantages and FRP is added to improve its quality in terms of strength. A study has been conducted on 21 cylinders based on their slenderness ratio. The slenderness ratios in the columns were 8, 16, and 24. At thicknesses of 5 mm and 7 mm, two types of wrap materials (UDCGFRP) and (WRGFRP)] were employed. Up to the point of failure, the columns were subjected to monotonic axial compressive force. The column’s yield loads, and ultimate load, were deduced from the load-deflection curves. The overall, uni-directional cloth provided the most effective confinement and led to a highly desirable failure mechanism, which was a gradual process.
{"title":"Follow effect of low cost glass fibre reinforced polymer (GFRP) on the performance of concentrically loaded concrete column","authors":"Pannirselvam N, Sudarsan J S, Nithiyanantham S","doi":"10.15625/2525-2518/18079","DOIUrl":"https://doi.org/10.15625/2525-2518/18079","url":null,"abstract":"(FRP) plays a major role in the strengthening of existing structures due to the age of the structure or natural calamities like earthquakes, floods, cyclones, etc. For reducing the size of structural members, the FRP wrapping assists to achieve the performance of the structure. Concrete is widely used due to its advantages and FRP is added to improve its quality in terms of strength. A study has been conducted on 21 cylinders based on their slenderness ratio. The slenderness ratios in the columns were 8, 16, and 24. At thicknesses of 5 mm and 7 mm, two types of wrap materials (UDCGFRP) and (WRGFRP)] were employed. Up to the point of failure, the columns were subjected to monotonic axial compressive force. The column’s yield loads, and ultimate load, were deduced from the load-deflection curves. The overall, uni-directional cloth provided the most effective confinement and led to a highly desirable failure mechanism, which was a gradual process.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139315985","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 : 2023-10-20DOI: 10.15625/2525-2518/17560
Nguyen Thuy Linh, Bui Thi Minh, Anh, T. Hiếu, Phi Thi Dao, Tran Thu Huong, Doan Thi Mai, Huong, P. Cuong
Schweinfurthins possess a wide diversity of important biological and pharmacological activities. To date, more than fifty schweinfurthins and their analogues have been prepared for the investigation of structure-function relationships. Schweinfurthin G, one of the most representative of schweinfurthins containing the hexahydroxanthene moiety, was found to strongly inhibit the growth of cancer cell lines when evaluated on the U87 cell line (EC50 of 0.04 µM), and on the KB cell line (IC50 of 0.06 µM). Ionic liquids have been regarded as “solvents of the future” and applied in various fields. They have been utilized most widely in modern organic synthesis as an environmentally friendly alternative to conventional organic solvents and catalysts due to their flexible, nonvolatile, noncorrosive, low viscous properties and they still maintain similar and sometimes enhanced chemical selectivity and reactivity of organic reactions. In this paper, we present the synthesis of intermediate compounds 2 and 3, which are the key compounds for synthesizing the derivatives of schweinfurthin G using chiral ionic liquid. These compounds are the key blocks to further synthesize schweinfurthin G derivatives for biological activity tests.
五味子呋喃类化合物具有多种重要的生物和药理活性。迄今为止，已经制备了 50 多种五味子呋喃素及其类似物，用于研究其结构与功能的关系。在对 U87 细胞系（EC50 为 0.04 µM）和 KB 细胞系（IC50 为 0.06 µM）进行评估时发现，Schweinfurthin G 是含有六氢噻吩分子的五味子呋喃类化合物中最具代表性的一种，能强烈抑制癌细胞系的生长。离子液体被视为 "未来的溶剂"，应用于各个领域。由于离子液体具有灵活、不挥发、无腐蚀性、低粘度等特性，它们在现代有机合成中作为传统有机溶剂和催化剂的环保型替代品得到了最广泛的应用。本文介绍了中间化合物 2 和 3 的合成，它们是利用手性离子液体合成 schweinfurthin G 衍生物的关键化合物。这些化合物是进一步合成用于生物活性测试的五味子呋喃素 G 衍生物的关键砌块。
{"title":"Synthesis of intermediate derivatives from Schweinfurthin G using chiral ionic liquid","authors":"Nguyen Thuy Linh, Bui Thi Minh, Anh, T. Hiếu, Phi Thi Dao, Tran Thu Huong, Doan Thi Mai, Huong, P. Cuong","doi":"10.15625/2525-2518/17560","DOIUrl":"https://doi.org/10.15625/2525-2518/17560","url":null,"abstract":"Schweinfurthins possess a wide diversity of important biological and pharmacological activities. To date, more than fifty schweinfurthins and their analogues have been prepared for the investigation of structure-function relationships. Schweinfurthin G, one of the most representative of schweinfurthins containing the hexahydroxanthene moiety, was found to strongly inhibit the growth of cancer cell lines when evaluated on the U87 cell line (EC50 of 0.04 µM), and on the KB cell line (IC50 of 0.06 µM). Ionic liquids have been regarded as “solvents of the future” and applied in various fields. They have been utilized most widely in modern organic synthesis as an environmentally friendly alternative to conventional organic solvents and catalysts due to their flexible, nonvolatile, noncorrosive, low viscous properties and they still maintain similar and sometimes enhanced chemical selectivity and reactivity of organic reactions. In this paper, we present the synthesis of intermediate compounds 2 and 3, which are the key compounds for synthesizing the derivatives of schweinfurthin G using chiral ionic liquid. These compounds are the key blocks to further synthesize schweinfurthin G derivatives for biological activity tests.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"24 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139316064","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 : 2023-10-20DOI: 10.15625/2525-2518/18427
Nguyen Thuy Ngoc, Truong Thi Kim, Nguyen Thi Quynh, Phung Thi Vi, Pham Hung Viet, Duong Hong Anh
The paddy soils were collected in the rice growing fields and the uncultivated lands around the Nam Son domestic waste landfill in Hanoi. The average concentration of 16 US EPA priority PAHs in dry soil was 61.61 ng/g, with a range of 22.15-115.1 ng/g. The higher levels of PAHs in soil samples were observed in cultivated paddy fields near the landfill in comparison with the fields far from the landfill. On the other hand, there was no difference in PAHs levels in cultivated paddy fields near the landfill and along the irrigation water canal. Concentrations of 16 PAHs in paddy soils decreased in the order: 5 rings > 3 rings > 4 rings > 2 rings > 6 rings in this area. The PAH isomeric diagnostic ratios including Fluth/(Fluth+Pyr) ratio (Ave 0.43, a range of 0.17-0.61), BaA/(BaA+Chr) ratio (Ave 0.51, a range of 0.26-0.63), IcdP/(IcdP+BghiP) ratio (Ave 0.71, a range of 0.51-0.90) indicated that the potential main sources emitted PAHs in paddy soils from pyrogenic biomass combustion and coal burning. Compared with the risk threshold causing adverse impacts on the ecological environment from different countries in the world, concentrations of PAHs in the soil surrounding the Nam Son landfill area were still below the affected limit. However, environmental quality around the landfill area still needs to be regularly monitored to take timely measures to protect the environment in this area.
{"title":"Polycyclic Aromatic Hydrocarbons (PAHs) in paddy soil around Nam Son landfill area, Ha Noi, Viet Nam","authors":"Nguyen Thuy Ngoc, Truong Thi Kim, Nguyen Thi Quynh, Phung Thi Vi, Pham Hung Viet, Duong Hong Anh","doi":"10.15625/2525-2518/18427","DOIUrl":"https://doi.org/10.15625/2525-2518/18427","url":null,"abstract":"The paddy soils were collected in the rice growing fields and the uncultivated lands around the Nam Son domestic waste landfill in Hanoi. The average concentration of 16 US EPA priority PAHs in dry soil was 61.61 ng/g, with a range of 22.15-115.1 ng/g. The higher levels of PAHs in soil samples were observed in cultivated paddy fields near the landfill in comparison with the fields far from the landfill. On the other hand, there was no difference in PAHs levels in cultivated paddy fields near the landfill and along the irrigation water canal. Concentrations of 16 PAHs in paddy soils decreased in the order: 5 rings > 3 rings > 4 rings > 2 rings > 6 rings in this area. The PAH isomeric diagnostic ratios including Fluth/(Fluth+Pyr) ratio (Ave 0.43, a range of 0.17-0.61), BaA/(BaA+Chr) ratio (Ave 0.51, a range of 0.26-0.63), IcdP/(IcdP+BghiP) ratio (Ave 0.71, a range of 0.51-0.90) indicated that the potential main sources emitted PAHs in paddy soils from pyrogenic biomass combustion and coal burning. Compared with the risk threshold causing adverse impacts on the ecological environment from different countries in the world, concentrations of PAHs in the soil surrounding the Nam Son landfill area were still below the affected limit. However, environmental quality around the landfill area still needs to be regularly monitored to take timely measures to protect the environment in this area.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"20 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139316152","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 : 2023-08-22DOI: 10.15625/2525-2518/17252
Huong Do, Thi Thanh, Tien Thanh Nguyen
Thanks to novel recombinant starch degrading enzymes which can directly hydrolyze raw starch at ambient temperature, the technology of hydrolysis of uncooked starch has recently been developed andproven to be effective. In combination with high substrate concentration (high gravity) approach, this technology not only saves the thermal energy for starch gelatinization but also reduces the impact of heat on valuable components in starch–containing raw materials. Black–purple rice is a specialty of Northwest Viet Nam, which contains high level of anthocyanin, a biologically active ingredient. In this study, commercial enzymes were applied to hydrolyze non–gelatinized black–purple rice to obtain anthocyanin–containing sugar solution. Factors affecting the starch conversion such as enzyme/substrate ratio, hydrolysis duration, temperature, and the presence of supporting enzymes in the hydrolysis process were investigated. The results showed that in the presence of Stargen 002, Viscozyme L, and Cellulast 1.5 L, more than 86 % of starch in a total of 320 g/L black-purple rice were converted into glucose after 72 hours at 50 °C. From black-purple rice, two products were received, including a glucose–rich hydrolysate (245.92 g/L) containing anthocyanin (30 mg/L) and a solid by–product rich in protein, which were very potential for food application.
由于新型重组淀粉降解酶可在常温下直接水解生淀粉，最近开发出了水解未熟化淀粉的技术，并被证明是有效的。该技术与高底物浓度（高重力）方法相结合，不仅节省了淀粉糊化的热能，还减少了热量对含淀粉原料中有价值成分的影响。黑紫色大米是越南西北部的特产，含有大量花青素（一种生物活性成分）。在这项研究中，使用商业酶水解未胶化的黑紫色大米，以获得含花青素的糖溶液。研究了影响淀粉转化率的因素，如酶/底物比例、水解持续时间、温度以及水解过程中是否存在辅助酶。结果表明，在使用 Stargen 002、Viscozyme L 和 Cellulast 1.5 L 的情况下，在 50 °C 下 72 小时后，总计 320 克/升的黑紫色大米中超过 86% 的淀粉转化为葡萄糖。从黑紫色大米中获得了两种产品，包括富含花青素（30 毫克/升）的葡萄糖水解物（245.92 克/升）和富含蛋白质的固体副产品，这两种产品在食品应用方面具有很大的潜力。
{"title":"High gravity enzymatic hydrolysis of non–gelatinized starch from black - purple rice","authors":"Huong Do, Thi Thanh, Tien Thanh Nguyen","doi":"10.15625/2525-2518/17252","DOIUrl":"https://doi.org/10.15625/2525-2518/17252","url":null,"abstract":"Thanks to novel recombinant starch degrading enzymes which can directly hydrolyze raw starch at ambient temperature, the technology of hydrolysis of uncooked starch has recently been developed andproven to be effective. In combination with high substrate concentration (high gravity) approach, this technology not only saves the thermal energy for starch gelatinization but also reduces the impact of heat on valuable components in starch–containing raw materials. Black–purple rice is a specialty of Northwest Viet Nam, which contains high level of anthocyanin, a biologically active ingredient. In this study, commercial enzymes were applied to hydrolyze non–gelatinized black–purple rice to obtain anthocyanin–containing sugar solution. Factors affecting the starch conversion such as enzyme/substrate ratio, hydrolysis duration, temperature, and the presence of supporting enzymes in the hydrolysis process were investigated. The results showed that in the presence of Stargen 002, Viscozyme L, and Cellulast 1.5 L, more than 86 % of starch in a total of 320 g/L black-purple rice were converted into glucose after 72 hours at 50 °C. From black-purple rice, two products were received, including a glucose–rich hydrolysate (245.92 g/L) containing anthocyanin (30 mg/L) and a solid by–product rich in protein, which were very potential for food application.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"2015 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139349647","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 : 2023-08-22DOI: 10.15625/2525-2518/16900
Nguyen Van Ngoc, Le Van Long, Dinh Ngoc Dzung, T. Huynh, Nguyen Thi Mai, B. Tung, B. Khuyen, Vu Dinh Lam
In this paper, a multifunctional metamaterial (MM) structure capable of performing as a polarization converter and absorber is proposed. By using DC bias voltage to control the capacitor of the integrated varactor, the near-field coupling in our structure can be manipulated to flexibly switch between polarization conversion (PC) mode and perfect absorption (PA) mode. The numerical simulation results show that in PC mode the polarization conversion ratio exceeds 90 % at 4 GHz, while the dual-band absorption is observed in PA mode with a value close to 90 % at 3.5 and 5.5 GHz. In addition, we also reduce the geometric sizes of the proposed structure to further examine its performance in the THz frequency range. Owing to its excellent characteristics in both PA and PC modes, the proposed hybrid MM structure is promising to apply in many fields such as radar, remote sensing, and satellite.
本文提出了一种能够用作偏振转换器和吸收器的多功能超材料（MM）结构。通过使用直流偏置电压来控制集成变容器的电容，我们结构中的近场耦合可以在极化转换（PC）模式和完美吸收（PA）模式之间灵活切换。数值模拟结果表明，在 PC 模式下，4 GHz 的极化转换率超过 90%，而在 PA 模式下，3.5 和 5.5 GHz 的双频吸收率接近 90%。此外，我们还缩小了拟议结构的几何尺寸，以进一步检验其在太赫兹频率范围内的性能。由于在 PA 和 PC 模式下均具有出色的特性，所提出的混合 MM 结构有望应用于雷达、遥感和卫星等多个领域。
{"title":"Controlling near-field coupling for switchable metamaterial between absorption and polarization-conversion functions","authors":"Nguyen Van Ngoc, Le Van Long, Dinh Ngoc Dzung, T. Huynh, Nguyen Thi Mai, B. Tung, B. Khuyen, Vu Dinh Lam","doi":"10.15625/2525-2518/16900","DOIUrl":"https://doi.org/10.15625/2525-2518/16900","url":null,"abstract":"In this paper, a multifunctional metamaterial (MM) structure capable of performing as a polarization converter and absorber is proposed. By using DC bias voltage to control the capacitor of the integrated varactor, the near-field coupling in our structure can be manipulated to flexibly switch between polarization conversion (PC) mode and perfect absorption (PA) mode. The numerical simulation results show that in PC mode the polarization conversion ratio exceeds 90 % at 4 GHz, while the dual-band absorption is observed in PA mode with a value close to 90 % at 3.5 and 5.5 GHz. In addition, we also reduce the geometric sizes of the proposed structure to further examine its performance in the THz frequency range. Owing to its excellent characteristics in both PA and PC modes, the proposed hybrid MM structure is promising to apply in many fields such as radar, remote sensing, and satellite.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139349554","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 : 2023-08-21DOI: 10.15625/2525-2518/18063
M. Ahmed, Fareeha Arshad
Phosphate enters the aquatic system through runoff from pastures, croplands, urban areas, and sewage treatment systems and fosters algal bloom causing eutrophication at higher concentrations in water. Therefore, controlling its concentration through routine monitoring of water quality in aquatic ecosystems is essential. Using a smartphone camera and colour analysis app, a simple colourimetric technique was developed to quantitatively detect inorganic phosphate in natural and treated drinking water samples using colourless leuco crystal violet (LCV). Upon reaction with phosphate (PO43−), LCV forms leuco crystal violet phosphate (LCV-P) complex with a violet colour and shows maximum absorbance at 583 nm. A light-sensitive colourimetric box with in-built LED light was constructed to maintain the consistency of the image quality for precise and accurate measurement. The Red, Green and Blue (RGB) analyses of the digital images were done to determine the linear response of the intensity of G against the concentration of the LCV-P complex. A microplate reader was also used to analyse the UV-Vis absorbance of the samples to validate the results further. Under optimum conditions, the colourimetric assay achieved a detection limit of 0.25 μM with a linear range between 0.1 and 1 μM. Thus, the proposed colourimetric assay was highly sensitive and selective towards phosphate in natural and drinking water samples.
{"title":"A colorimetric assay with leuco crystal violet for the detection of inorganic phosphate in water","authors":"M. Ahmed, Fareeha Arshad","doi":"10.15625/2525-2518/18063","DOIUrl":"https://doi.org/10.15625/2525-2518/18063","url":null,"abstract":"Phosphate enters the aquatic system through runoff from pastures, croplands, urban areas, and sewage treatment systems and fosters algal bloom causing eutrophication at higher concentrations in water. Therefore, controlling its concentration through routine monitoring of water quality in aquatic ecosystems is essential. Using a smartphone camera and colour analysis app, a simple colourimetric technique was developed to quantitatively detect inorganic phosphate in natural and treated drinking water samples using colourless leuco crystal violet (LCV). Upon reaction with phosphate (PO43−), LCV forms leuco crystal violet phosphate (LCV-P) complex with a violet colour and shows maximum absorbance at 583 nm. A light-sensitive colourimetric box with in-built LED light was constructed to maintain the consistency of the image quality for precise and accurate measurement. The Red, Green and Blue (RGB) analyses of the digital images were done to determine the linear response of the intensity of G against the concentration of the LCV-P complex. A microplate reader was also used to analyse the UV-Vis absorbance of the samples to validate the results further. Under optimum conditions, the colourimetric assay achieved a detection limit of 0.25 μM with a linear range between 0.1 and 1 μM. Thus, the proposed colourimetric assay was highly sensitive and selective towards phosphate in natural and drinking water samples.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87574447","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 : 2023-08-02DOI: 10.15625/2525-2518/17343
Phạm Quốc Việt, N. T. Hue, Nguyen Thi Truc Phuong, Mai, Le Phuong Thu
This study aimed to determine the content of heavy metals (Cu, Ni, Pb, Zn, Cd, Cr, and As) and polyaromatic hydrocarbon (PAHs), and focus on their relationship in particulate matter (<10μm) contained in the flue gas of the incinerators. Samples were collected in the exhausted gas of 5 municipal solid waste incinerators located in Bac Giang, Bac Ninh, Hai Duong, Hanoi, and Hai Phong. Heavy metals and PAHs were analyzed by ICP-MS and GC-MS, respectively. The heavy metal content shows a significant difference between incinerators, varying from 0.822 to 6.13 × 103 µg/Nm3. In which, the predominant element in the PM10 samples was zinc, accounting for 80% of the total content of studied elements, it was mixed with Pb and Cu (10 to 20%). The contribution of Cd was stable at roughly 5% of the total heavy metal content. Meanwhile, total polyaromatic hydrocarbon exhibited a fairly low concentration, varying from 21.9 to 994 µg/Nm3, of which PAHs have the carcinogenic potential ranging from 21.3 to 73.2% of total PAHs. These results hypothesized the correlation between Zn and Pb to the formation of PAHs during the combustion and discharge to the environment through waste dust. However, the low molecular PAH content decreased when heavy metal concentration increased.
{"title":"Correlation between heavy metals and polyaromatic hydrocarbons of particulate matter in the flue gas of municipal solid waste incinerators in north Vietnam","authors":"Phạm Quốc Việt, N. T. Hue, Nguyen Thi Truc Phuong, Mai, Le Phuong Thu","doi":"10.15625/2525-2518/17343","DOIUrl":"https://doi.org/10.15625/2525-2518/17343","url":null,"abstract":"This study aimed to determine the content of heavy metals (Cu, Ni, Pb, Zn, Cd, Cr, and As) and polyaromatic hydrocarbon (PAHs), and focus on their relationship in particulate matter (<10μm) contained in the flue gas of the incinerators. Samples were collected in the exhausted gas of 5 municipal solid waste incinerators located in Bac Giang, Bac Ninh, Hai Duong, Hanoi, and Hai Phong. Heavy metals and PAHs were analyzed by ICP-MS and GC-MS, respectively. The heavy metal content shows a significant difference between incinerators, varying from 0.822 to 6.13 × 103 µg/Nm3. In which, the predominant element in the PM10 samples was zinc, accounting for 80% of the total content of studied elements, it was mixed with Pb and Cu (10 to 20%). The contribution of Cd was stable at roughly 5% of the total heavy metal content. Meanwhile, total polyaromatic hydrocarbon exhibited a fairly low concentration, varying from 21.9 to 994 µg/Nm3, of which PAHs have the carcinogenic potential ranging from 21.3 to 73.2% of total PAHs. These results hypothesized the correlation between Zn and Pb to the formation of PAHs during the combustion and discharge to the environment through waste dust. However, the low molecular PAH content decreased when heavy metal concentration increased.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85883967","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 : 2023-08-02DOI: 10.15625/2525-2518/16449
H. Thi, T. Minh, D. Thi, Hanh, Phan Quang Thang, T. T. Hà
The widespread use of flame retardants in commercial and industrial products has led to their increased presence in the environment. Recently, indoor dust has been identified as a major human exposure route for flame retardants. In the present study, brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) were examined in indoor dust samples collected from apartments in Hanoi, Vietnam. OPFRs were detected at the highest concentrations with the mean concentration of ∑OPFRs was 8700 ng/g (ranged from 1400 to 18000 ng/g). Tris(1-chloro-2-propyl) phosphate (TCPP) and tris(2-butoxyethyl) phosphate (TBOEP) were the most abundant OPFRs in all indoor dust samples, accounting for 50 % (ranged 22 – 69 %) and 33 % (ranged 16 – 63 %) of the total OPFRs levels, respectively. The mean concentrations of total polybrominated diphenyl ethers (PBDEs) and total novel brominated flame retardants (NBFRs) in these samples were 200 ng/g (ranged 67 - 480 ng/g) and 310 ng/g (ranged 56 - 1500 ng/g), respectively. Polybrominated diphenyl ether congener 209 (BDE 209) and decabromodiphenyl ethane (DBDPE) were the most predominant components in PBDEs and NBFRs, respectively. Other BFRs were only found in some samples at very low levels. The estimated daily intake doses (IDs) of FRs via dust ingestion were calculated for both adults and children. The results revealed that the estimated levels of compound exposure through dust ingestion, even under the high-exposure scenario were also below their reference dose (RfD) values, indicating that human health risks from exposure to flame retardants (FRs) via indoor dust ingestion are not significant.
{"title":"Occurrence and human exposure risk assessment of brominated and organophosphate flame retardants in indoor dust in Ha Noi, Viet Nam","authors":"H. Thi, T. Minh, D. Thi, Hanh, Phan Quang Thang, T. T. Hà","doi":"10.15625/2525-2518/16449","DOIUrl":"https://doi.org/10.15625/2525-2518/16449","url":null,"abstract":"The widespread use of flame retardants in commercial and industrial products has led to their increased presence in the environment. Recently, indoor dust has been identified as a major human exposure route for flame retardants. In the present study, brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) were examined in indoor dust samples collected from apartments in Hanoi, Vietnam. OPFRs were detected at the highest concentrations with the mean concentration of ∑OPFRs was 8700 ng/g (ranged from 1400 to 18000 ng/g). Tris(1-chloro-2-propyl) phosphate (TCPP) and tris(2-butoxyethyl) phosphate (TBOEP) were the most abundant OPFRs in all indoor dust samples, accounting for 50 % (ranged 22 – 69 %) and 33 % (ranged 16 – 63 %) of the total OPFRs levels, respectively. The mean concentrations of total polybrominated diphenyl ethers (PBDEs) and total novel brominated flame retardants (NBFRs) in these samples were 200 ng/g (ranged 67 - 480 ng/g) and 310 ng/g (ranged 56 - 1500 ng/g), respectively. Polybrominated diphenyl ether congener 209 (BDE 209) and decabromodiphenyl ethane (DBDPE) were the most predominant components in PBDEs and NBFRs, respectively. Other BFRs were only found in some samples at very low levels. The estimated daily intake doses (IDs) of FRs via dust ingestion were calculated for both adults and children. The results revealed that the estimated levels of compound exposure through dust ingestion, even under the high-exposure scenario were also below their reference dose (RfD) values, indicating that human health risks from exposure to flame retardants (FRs) via indoor dust ingestion are not significant.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91070786","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 : 2023-08-02DOI: 10.15625/2525-2518/17260
Anh Ngoc Pham, Anh Kieu Ha, Thuy Thi Tran
Yeast living in honey, an environment with high sugar content (up to 70 %, w/v), normally shows good resistance to the high level of osmotic pressure; they are of high potential for application in many fields. There were not many studies on the genetic diversity and biological characteristics of yeast from honey in Vietnam. This study aims to (1) evaluate the genetic diversity of antibacterial yeast isolated from natural honey and beeswax in Son La province by RAPD (Random Amplified Polymorphic DNA) and (2) study some biological characteristics of them. The research results may contribute to the scientific basis for screening yeast strains applied in different fields such as bioethanol and probiotic production. Sixty-eight yeast strains were isolated from natural honey and beeswax collected in Son La. Among them, twenty-one strains showed antibacterial activity against at least a tested bacterium including Escherichia coli, Bacillus subtilis, and Serratia marcescens. These yeast strains were genetically distinct in the RAPD analysis using M13 and (GTG)5 primers. Evaluation of yeast growing in the medium containing high glucose concentration (30 - 40 %, w/v) or high ethanol concentration (5 - 10 %, v/v) has shown some yeast strains that can tolerate high osmotic pressure and high ethanol concentration for different applications. YC.8 and YC.61 strains exhibited relatively good survival rates in two phases of digestion and have a wide pH range (2 - 7). YC.8 strain expressed the most potential for human or animal probiotics.
酵母菌生活在蜂蜜这种含糖量高（高达 70%，w/v）的环境中，通常对高渗透压有很好的抵抗力；它们在许多领域都有很高的应用潜力。关于越南蜂蜜酵母的遗传多样性和生物特性的研究并不多。本研究旨在：（1）通过 RAPD（随机扩增多态 DNA）评估从 Son La 省的天然蜂蜜和蜂蜡中分离出来的抗菌酵母的遗传多样性；（2）研究它们的一些生物学特征。研究结果可为筛选生物乙醇和益生菌生产等不同领域应用的酵母菌株提供科学依据。从 Son La 采集的天然蜂蜜和蜂蜡中分离出 68 株酵母菌。其中，21 株酵母菌对至少一种受试细菌（包括大肠杆菌、枯草杆菌和 Serratia marcescens）具有抗菌活性。在使用 M13 和 (GTG)5 引物进行的 RAPD 分析中，这些酵母菌株在遗传学上是不同的。对在含高浓度葡萄糖（30 - 40 %，w/v）或高浓度乙醇（5 - 10 %，v/v）的培养基中生长的酵母菌进行的评估显示，一些酵母菌株能耐受高渗透压和高浓度乙醇，可用于不同用途。YC.8 和 YC.61 菌株在消化的两个阶段都表现出相对较好的存活率，并且具有较宽的 pH 值范围（2 - 7）。YC.8 菌株最有可能成为人类或动物益生菌。
{"title":"Genetic diversity and some biological characteristics of antibacterial yeasts isolated from natural honey and beeswax in Son La province","authors":"Anh Ngoc Pham, Anh Kieu Ha, Thuy Thi Tran","doi":"10.15625/2525-2518/17260","DOIUrl":"https://doi.org/10.15625/2525-2518/17260","url":null,"abstract":"Yeast living in honey, an environment with high sugar content (up to 70 %, w/v), normally shows good resistance to the high level of osmotic pressure; they are of high potential for application in many fields. There were not many studies on the genetic diversity and biological characteristics of yeast from honey in Vietnam. This study aims to (1) evaluate the genetic diversity of antibacterial yeast isolated from natural honey and beeswax in Son La province by RAPD (Random Amplified Polymorphic DNA) and (2) study some biological characteristics of them. The research results may contribute to the scientific basis for screening yeast strains applied in different fields such as bioethanol and probiotic production. Sixty-eight yeast strains were isolated from natural honey and beeswax collected in Son La. Among them, twenty-one strains showed antibacterial activity against at least a tested bacterium including Escherichia coli, Bacillus subtilis, and Serratia marcescens. These yeast strains were genetically distinct in the RAPD analysis using M13 and (GTG)5 primers. Evaluation of yeast growing in the medium containing high glucose concentration (30 - 40 %, w/v) or high ethanol concentration (5 - 10 %, v/v) has shown some yeast strains that can tolerate high osmotic pressure and high ethanol concentration for different applications. YC.8 and YC.61 strains exhibited relatively good survival rates in two phases of digestion and have a wide pH range (2 - 7). YC.8 strain expressed the most potential for human or animal probiotics.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139352096","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}
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