Pub Date : 2023-04-24DOI: 10.25073/2588-1140/vnunst.5312
Dang Thu Quynh, N. Hoang, Nguyen Ngoc Lan, Le Viet Hoang, D. H. Nghi
Laccase (EC 1.10.3.2) is an enzyme belonging to the polyphenol oxidase groups, which plays an important role in the oxidation of a wide variety of aromatic substrates, such as lignin, phenol, polyamine, and aryl diamines, as well as a number of other phenolic compounds or inorganic ions in the presence of oxygen. Laccase is widely applied in many different fields, especially in the textile industry, dyeing, and environmental pollution treatment. In this study, we have successfully cloned and expressed cDNA coding for laccase from Pleurotus pulmonarius MPN18 (PpLac). cDNA corresponds to the gene laccase (size 1566 bp) was attached to pET 21a(+) vector and expressed in E. coli BL21, after that the enzyme was purified through HisTrapTM sp 5mL column. The purified PpLac had an activity of 899.8 U, a 74% yield with a purity of 15.2 -fold, and was tested by SDS-PAGE electrophoresis with a molecular weight of Mw = 55 kDa. Enzyme displayed optimal activity at 50 ºC and pH 4.0. Enzyme had optimal activity of 20-40 ºC after 120 min incubation and pH 4 after 6 h incubation. In future, the recombinant enzyme will be characterized for supplementation into enzyme cocktail in the treatment of lignocellulosic material.
{"title":"Cloning, Experession, and Characterization of a Laccase from the White Rot Fungi Pleurotus pulmonarius MPN18","authors":"Dang Thu Quynh, N. Hoang, Nguyen Ngoc Lan, Le Viet Hoang, D. H. Nghi","doi":"10.25073/2588-1140/vnunst.5312","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5312","url":null,"abstract":"Laccase (EC 1.10.3.2) is an enzyme belonging to the polyphenol oxidase groups, which plays an important role in the oxidation of a wide variety of aromatic substrates, such as lignin, phenol, polyamine, and aryl diamines, as well as a number of other phenolic compounds or inorganic ions in the presence of oxygen. Laccase is widely applied in many different fields, especially in the textile industry, dyeing, and environmental pollution treatment. In this study, we have successfully cloned and expressed cDNA coding for laccase from Pleurotus pulmonarius MPN18 (PpLac). cDNA corresponds to the gene laccase (size 1566 bp) was attached to pET 21a(+) vector and expressed in E. coli BL21, after that the enzyme was purified through HisTrapTM sp 5mL column. The purified PpLac had an activity of 899.8 U, a 74% yield with a purity of 15.2 -fold, and was tested by SDS-PAGE electrophoresis with a molecular weight of Mw = 55 kDa. Enzyme displayed optimal activity at 50 ºC and pH 4.0. Enzyme had optimal activity of 20-40 ºC after 120 min incubation and pH 4 after 6 h incubation. In future, the recombinant enzyme will be characterized for supplementation into enzyme cocktail in the treatment of lignocellulosic material.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86947085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-21DOI: 10.25073/2588-1140/vnunst.5512
Pham Huynh Thanh Trang, N. H. Triều, N. Trang, Nguyen Thi Hong Nham, N. M. Viet
In recent years, the problem of environmental pollution is becoming extremely serious. Especially, environmental pollution caused by textile dyes not only affects living organisms in the water but also affects human health. There are many methods applied to remove dyes in water; in which, photocatalysis has been proven to be an efficient method. The g-C3N4 is a polymer material with small bandgap energy (about 2,7 eV) as well as chemical and thermal stability in the ambient environment. In this study, the g-C3N4 material was successfully synthesized from urea calcined at 550 0C, and the modified materials αFe2O3/g-C3N4 were also successfully prepared by hydrothermal method. The synthesized materials were characterized by modern analytical techniques, such as SEM-EDX, XRD, UV-Vis, and FT-IR. The experimental results showed that synthesized materials have high efficiency in removing Congo Red dye in water under visible light irradiation. Especially, the 7% αFe2O3/g-C3N4 material had the best efficiency of Congo Red treatment, with an efficiency of up to 93.59% at pH 5 after 150 minutes.
{"title":"Synthesis and Characterization of αFe2O4/g-C3N4 Materials for Treatment of Congo Red Dye in Water","authors":"Pham Huynh Thanh Trang, N. H. Triều, N. Trang, Nguyen Thi Hong Nham, N. M. Viet","doi":"10.25073/2588-1140/vnunst.5512","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5512","url":null,"abstract":"In recent years, the problem of environmental pollution is becoming extremely serious. Especially, environmental pollution caused by textile dyes not only affects living organisms in the water but also affects human health. There are many methods applied to remove dyes in water; in which, photocatalysis has been proven to be an efficient method. The g-C3N4 is a polymer material with small bandgap energy (about 2,7 eV) as well as chemical and thermal stability in the ambient environment. In this study, the g-C3N4 material was successfully synthesized from urea calcined at 550 0C, and the modified materials αFe2O3/g-C3N4 were also successfully prepared by hydrothermal method. The synthesized materials were characterized by modern analytical techniques, such as SEM-EDX, XRD, UV-Vis, and FT-IR. The experimental results showed that synthesized materials have high efficiency in removing Congo Red dye in water under visible light irradiation. Especially, the 7% αFe2O3/g-C3N4 material had the best efficiency of Congo Red treatment, with an efficiency of up to 93.59% at pH 5 after 150 minutes.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84459023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.25073/2588-1140/vnunst.5514
Ngo Quoc Huy, N. Mai, Bui Thi Thao Anh, Lê Thị Huyền
Using various chromatographic methods, five compounds including three flavone C-glycosides, isoviolanthin (1), isoorientin (2), isovitexin (3), and two megastigmanes excoecarioside A (4), corchoionoside C (5) were isolated from the leaves of Tinospora sinensis (Lour.) Merr. Their structures were identified based on spectroscopic methods and comparisons with those reported in the literature.
{"title":"Flavone C-glycosides and Megastigmanes from the Leaves of Tinospora Sinensis","authors":"Ngo Quoc Huy, N. Mai, Bui Thi Thao Anh, Lê Thị Huyền","doi":"10.25073/2588-1140/vnunst.5514","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5514","url":null,"abstract":"Using various chromatographic methods, five compounds including three flavone C-glycosides, isoviolanthin (1), isoorientin (2), isovitexin (3), and two megastigmanes excoecarioside A (4), corchoionoside C (5) were isolated from the leaves of Tinospora sinensis (Lour.) Merr. Their structures were identified based on spectroscopic methods and comparisons with those reported in the literature.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88765003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-14DOI: 10.25073/2588-1140/vnunst.5544
Ngo Van An, Nguyen Thi Kim Chi, T. Khanh, Duong Xuan Quan, P. Q. Trung, Ngo Hong Anh Thu
The peels of grapefruit are a rich source of Pectin and Cellulose. This study focuses on the extraction of Pectin and Cellulose from grapefruit peels, and the production of carboxymethyl Cellulose (CMC) from extracted products. Firstly, the extraction conditions of Pectin from grapefruit peels were optimized to obtain a high yield of Pectins such as extraction time and citric acid concentration. The weight, purity, and esterification degree of Pectin were also determined. The highest yield of Pectin is 32.12% in the extraction conditions with pH 1.25 for 60 minutes at 80 oC. The Pectin product is of 84.02% purity at 29,427 g/mol of weight with 86.40% esterification degree. For extraction of Cellulose from grapefruit peels, the highest yield of Cellulose is 45.08% in the conditions with a pH of nitric acid 0.75 for 70 minutes at 90 oC. After that, the extracted Cellulose was converted to Carboxymethyl Cellulose by Monochloroacetic acid etherification. The characterization of Pectin, Cellulose, and CMC is determined through Scanning Electron Microscopy (SEM) and Infrared spectrums. The experimental results also showed that Pectin and Cellulose were successfully extracted from grapefruit peels and Carboxymethyl Cellulose was successfully produced from the extracted Cellulose.
{"title":"Extraction of Pectin and Cellulose from Grapefruit Peels and Production of Carboxymethyl Cellulose","authors":"Ngo Van An, Nguyen Thi Kim Chi, T. Khanh, Duong Xuan Quan, P. Q. Trung, Ngo Hong Anh Thu","doi":"10.25073/2588-1140/vnunst.5544","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5544","url":null,"abstract":"The peels of grapefruit are a rich source of Pectin and Cellulose. This study focuses on the extraction of Pectin and Cellulose from grapefruit peels, and the production of carboxymethyl Cellulose (CMC) from extracted products. Firstly, the extraction conditions of Pectin from grapefruit peels were optimized to obtain a high yield of Pectins such as extraction time and citric acid concentration. The weight, purity, and esterification degree of Pectin were also determined. The highest yield of Pectin is 32.12% in the extraction conditions with pH 1.25 for 60 minutes at 80 oC. The Pectin product is of 84.02% purity at 29,427 g/mol of weight with 86.40% esterification degree. For extraction of Cellulose from grapefruit peels, the highest yield of Cellulose is 45.08% in the conditions with a pH of nitric acid 0.75 for 70 minutes at 90 oC. After that, the extracted Cellulose was converted to Carboxymethyl Cellulose by Monochloroacetic acid etherification. The characterization of Pectin, Cellulose, and CMC is determined through Scanning Electron Microscopy (SEM) and Infrared spectrums. The experimental results also showed that Pectin and Cellulose were successfully extracted from grapefruit peels and Carboxymethyl Cellulose was successfully produced from the extracted Cellulose.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85041797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-13DOI: 10.25073/2588-1140/vnunst.5427
Do Quang Trung
Biocontrol of stem end disease agent, Alternaria alternata YZU, on pitaya is more interested in altering the application of chemical pesticides. This study was conducted to characterize antagonistic phosphate solubilizing bacteria (PSB) from rhizosphere soil for their biocontrol activities against A. alternata YZU under laboratory and greenhouse conditions. Six PSB isolated from 31 rhizosphere soil samples were tested for inhibiting the mycelial growth of A. alternata YZU in dual cultures. Six isolates were determined to inhibit the mycelial growth of A. alternata YZU. Among them, PSB31 presented the highest level of antagonistic activity against A. alternata YZU with a mean inhibition diameter of 0.64 ± 0.02 cm, while the other strains, including PSB11, PSB21, PSB41, PSB51, and PSB61 presented a weaker inhibition. The results also showed that the strain PSB31 was identified as Bacillus sp. strain PSB31 (Accession number: ON422095) and could control the mycelial growth of A. alternata YZU by secreting antifungal metabolites. Moreover, an in vivo antagonistic experiment of PSB31 on pitaya twigs showed a significant reduction of lesions on twigs than the control. The results suggested that the isolated PSB31 is a potential biological control agent. Further studies should be done to identify the biochemical basis of their activity against A. alternata YZU.
{"title":"Biocontrol Stem-end Rot Disease Agent, Alternaria alternata YZU, on Pitaya by Soil Phosphate Solubilizing Bacteria","authors":"Do Quang Trung","doi":"10.25073/2588-1140/vnunst.5427","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5427","url":null,"abstract":"Biocontrol of stem end disease agent, Alternaria alternata YZU, on pitaya is more interested in altering the application of chemical pesticides. This study was conducted to characterize antagonistic phosphate solubilizing bacteria (PSB) from rhizosphere soil for their biocontrol activities against A. alternata YZU under laboratory and greenhouse conditions. Six PSB isolated from 31 rhizosphere soil samples were tested for inhibiting the mycelial growth of A. alternata YZU in dual cultures. Six isolates were determined to inhibit the mycelial growth of A. alternata YZU. Among them, PSB31 presented the highest level of antagonistic activity against A. alternata YZU with a mean inhibition diameter of 0.64 ± 0.02 cm, while the other strains, including PSB11, PSB21, PSB41, PSB51, and PSB61 presented a weaker inhibition. The results also showed that the strain PSB31 was identified as Bacillus sp. strain PSB31 (Accession number: ON422095) and could control the mycelial growth of A. alternata YZU by secreting antifungal metabolites. Moreover, an in vivo antagonistic experiment of PSB31 on pitaya twigs showed a significant reduction of lesions on twigs than the control. The results suggested that the isolated PSB31 is a potential biological control agent. Further studies should be done to identify the biochemical basis of their activity against A. alternata YZU.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75780416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-11DOI: 10.25073/2588-1140/vnunst.5288
Tu Quang Long, Nguyen Thanh Tan, Tran Thien Thien, Võ Nguyễn Hải Vy, T. Hiếu
Hand, Foot, and Mouth disease (HFMD) is a highly contagious disease caused by enteroviruses, which is common in Asia-Pacific countries, including China, Hong Kong, Korea, Malaysia, Singapore, Thailand, and Vietnam. Children are more susceptible to infection, especially newborns and children under-5-year-old. HFMD may cause severe symptoms like encephalitis, meningitis, myocarditis, and acute pulmonary edema which can lead to death if no early detection or prompt treating is carried out. Various professional researches indicated the main causes of HFMD were enteroviruses in the Picornaviridae family, particularly Coxsackievirus A16 (CVA16) and Enterovirus 71 (EV71). Both factors cause the same beginning symptoms, but while CVA16’s are mild and can be self-recuperated after 10-14 days, EV71’s are more dangerous and can lead to neurological, cardiovascular, and respiratory complications, causing death or permanent brain damages. Preventing EV71 infection is extremely necessary as it not only decreases severe HFMD but also interferes with the virus speciation through homologous recombination to reduce the complexity of epidemic situation in the world. Therefore, synthesizing information about the virus life cycle and prevention strategies against EV71 is crucial and essential to provide an overview about the potential methods for vaccines and medicines development or food supplement manufactures which contributes to preventing EV71 infection.
{"title":"EV-A71 Infections: Life Cycle and Prevention Strategies","authors":"Tu Quang Long, Nguyen Thanh Tan, Tran Thien Thien, Võ Nguyễn Hải Vy, T. Hiếu","doi":"10.25073/2588-1140/vnunst.5288","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5288","url":null,"abstract":"Hand, Foot, and Mouth disease (HFMD) is a highly contagious disease caused by enteroviruses, which is common in Asia-Pacific countries, including China, Hong Kong, Korea, Malaysia, Singapore, Thailand, and Vietnam. Children are more susceptible to infection, especially newborns and children under-5-year-old. HFMD may cause severe symptoms like encephalitis, meningitis, myocarditis, and acute pulmonary edema which can lead to death if no early detection or prompt treating is carried out. Various professional researches indicated the main causes of HFMD were enteroviruses in the Picornaviridae family, particularly Coxsackievirus A16 (CVA16) and Enterovirus 71 (EV71). Both factors cause the same beginning symptoms, but while CVA16’s are mild and can be self-recuperated after 10-14 days, EV71’s are more dangerous and can lead to neurological, cardiovascular, and respiratory complications, causing death or permanent brain damages. \u0000Preventing EV71 infection is extremely necessary as it not only decreases severe HFMD but also interferes with the virus speciation through homologous recombination to reduce the complexity of epidemic situation in the world. Therefore, synthesizing information about the virus life cycle and prevention strategies against EV71 is crucial and essential to provide an overview about the potential methods for vaccines and medicines development or food supplement manufactures which contributes to preventing EV71 infection.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84787227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-10DOI: 10.25073/2588-1140/vnunst.5094
Ethanol containing beverages (alcoholic beverages) are socially acceptable beverages that are expected to provide refreshment, satisfaction and stress relief. Common types of ethanol containing beverages include: wine, beer, and syrup. According to the World Health Organization, alcohol abuse is a risk factor for high mortality and many diseases in humans such as fatty liver, hepatomegaly, cirrhosis, liver cancer, larynx cancer, nasopharynx cancer, stomach and esophageal cancer,… In human, ethanol is eliminated mainly through metabolism in two ways: Oxidative pathway with the participation of enzymes: alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), cytochrome P450 and catalase; non-oxidative pathways involving phospholipase and fatty acid ethyl ester (FAEE) synthase. Alcohol abuse is believed to be caused by genetic factors (ADH, ALDH,...), psychological and social factors. Single nucleotide polymorphisms (SNPs) in genes encoding enzymes involved in ethanol metabolism helped explaining why certain ethnic groups and individuals have higher or lower ethanol-related health risks and development of alcohol abuse syndrome. In Vietnam, using ethanol containing beverages is a habit imbued with traditional culture. At the same time, wine and beer abuse is already a problem and causes many serious consequences for public health, family happiness and social safety. Meanwhile, the concept that drinking alcohol helps relieve nervous tension is common, many people still feel subjectively drinking alcohol to be healthier. Some studies have shown differences about SNPs of gene encoding enzymes involved in ethanol metabolism in Vietnamese. Therefore, it is necessary to study the relationship between SNPs of these genes with alcohol and beer drinking habits leading to abuse and the risks of ethanol-related diseases.
{"title":"The Association between Genetic and Racial Factors in Ethanol Containing Beverages Metabolism and Health Risks in Human","authors":"","doi":"10.25073/2588-1140/vnunst.5094","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5094","url":null,"abstract":"Ethanol containing beverages (alcoholic beverages) are socially acceptable beverages that are expected to provide refreshment, satisfaction and stress relief. Common types of ethanol containing beverages include: wine, beer, and syrup. According to the World Health Organization, alcohol abuse is a risk factor for high mortality and many diseases in humans such as fatty liver, hepatomegaly, cirrhosis, liver cancer, larynx cancer, nasopharynx cancer, stomach and esophageal cancer,… In human, ethanol is eliminated mainly through metabolism in two ways: Oxidative pathway with the participation of enzymes: alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), cytochrome P450 and catalase; non-oxidative pathways involving phospholipase and fatty acid ethyl ester (FAEE) synthase. Alcohol abuse is believed to be caused by genetic factors (ADH, ALDH,...), psychological and social factors. Single nucleotide polymorphisms (SNPs) in genes encoding enzymes involved in ethanol metabolism helped explaining why certain ethnic groups and individuals have higher or lower ethanol-related health risks and development of alcohol abuse syndrome. In Vietnam, using ethanol containing beverages is a habit imbued with traditional culture. At the same time, wine and beer abuse is already a problem and causes many serious consequences for public health, family happiness and social safety. Meanwhile, the concept that drinking alcohol helps relieve nervous tension is common, many people still feel subjectively drinking alcohol to be healthier. Some studies have shown differences about SNPs of gene encoding enzymes involved in ethanol metabolism in Vietnamese. Therefore, it is necessary to study the relationship between SNPs of these genes with alcohol and beer drinking habits leading to abuse and the risks of ethanol-related diseases.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77320799","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 : 2023-03-14DOI: 10.25073/2588-1140/vnunst.5039
N. Thanh
This article synthesized the epoxy alkyd ester resin by modifying alkyd resin with epoxy resin. The characteristics of synthesized resin was considered through the thermo-oxidation resistance, the chemical resistance (in 5 wt.% HCl, or in 5 wt.% NaCl solution), the UV-thermo-humidity complex stability (30 cycles, each cycle of 8 hours in UV irradiation at 60 °C and followed by 4 hours of humidity condensation at 50 °C), and the thermal shock resistance (7 cycles, each cycle of 10 minutes in refrigerated chamber at - 50 °C and 10 minutes in oven chamber at + 50 °C) The results showed that the thermo-oxidation resistance, the chemical resistance, and the UV-thermo-humiditycomplex stability of the ester epoxy alkyd paint film were higher than that of alkyd paint film, while the thermal shock ability was similar to that of the alkyd paint.
{"title":"Modification of Alkyd with Epoxy and its Application for Paint. Part 2: Durability of Paint Manufactured from this Ester","authors":"N. Thanh","doi":"10.25073/2588-1140/vnunst.5039","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5039","url":null,"abstract":"This article synthesized the epoxy alkyd ester resin by modifying alkyd resin with epoxy resin. The characteristics of synthesized resin was considered through the thermo-oxidation resistance, the chemical resistance (in 5 wt.% HCl, or in 5 wt.% NaCl solution), the UV-thermo-humidity complex stability (30 cycles, each cycle of 8 hours in UV irradiation at 60 °C and followed by 4 hours of humidity condensation at 50 °C), and the thermal shock resistance (7 cycles, each cycle of 10 minutes in refrigerated chamber at - 50 °C and 10 minutes in oven chamber at + 50 °C) The results showed that the thermo-oxidation resistance, the chemical resistance, and the UV-thermo-humiditycomplex stability of the ester epoxy alkyd paint film were higher than that of alkyd paint film, while the thermal shock ability was similar to that of the alkyd paint.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81599123","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 : 2023-03-03DOI: 10.25073/2588-1140/vnunst.5435
Nguyen Manh Linh, P. Tam, Do Thao Thuyen, N. T. Dat, T. T. Vân, D. T. Nhung, L. T. Anh
A series of eight 3-oxapentane podand derivatives was successfully prepared based on the croton condensation reaction from 1,5-bis(aryl)-1,5-dithia-3-dioxadecane and 1,5-bis(aryl)-1,3,5-trioxadecane with bezaldehyde or acetophenone derivatives in acidic condition. These synthesized derivatives have structure of acyclic crown rings inserted by polyether or polythiaether chain and vinyl ketone chain conjugated with aryl group. Therefore, they are important sources for host-guest chemistry. They can wrap around a central alkali metal cations as well as organic cations and anions or even molecules to make interesting ion pair receptors. Structure of new podands was determined by spectral analyses including IR, 1H NMR, MS spectrocopies.
{"title":"Synthesis and Structural Characterization of some 3-oxapentane Podand Derivatives","authors":"Nguyen Manh Linh, P. Tam, Do Thao Thuyen, N. T. Dat, T. T. Vân, D. T. Nhung, L. T. Anh","doi":"10.25073/2588-1140/vnunst.5435","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5435","url":null,"abstract":"A series of eight 3-oxapentane podand derivatives was successfully prepared based on the croton condensation reaction from 1,5-bis(aryl)-1,5-dithia-3-dioxadecane and 1,5-bis(aryl)-1,3,5-trioxadecane with bezaldehyde or acetophenone derivatives in acidic condition. These synthesized derivatives have structure of acyclic crown rings inserted by polyether or polythiaether chain and vinyl ketone chain conjugated with aryl group. Therefore, they are important sources for host-guest chemistry. They can wrap around a central alkali metal cations as well as organic cations and anions or even molecules to make interesting ion pair receptors. Structure of new podands was determined by spectral analyses including IR, 1H NMR, MS spectrocopies.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73052512","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 : 2023-03-03DOI: 10.25073/2588-1140/vnunst.5360
C. Hang, Vo Mai Nhu Hieu, P. Trinh, Thanh Thi Thu Thuy, Quach Thi Minh Thu, Tran Nguyen Ha Vy, N. T. Thuan, T. T. Vân
In this study, the structural characteristics of a polysaccharide extracted from the Ulva fasciata green seaweed were determined using the chemical composition analytical methods combined with IR, MS, and NMR spectra. The results showed that the polysaccharide consists of two major repeating disaccharide units designated as ulvanobiuronic acid 3-sulfate type A (A3s) [→4)-β-D-GlcA-(1 → 4)-α-L-Rha 3S-(1→] and type B (B3s) [→4)-α-LIdoA-(1 → 4)-α-L-Rha 3s(1→]. This kind of polysaccharide exhibited a significant in vitro antioxidant activity. This study demonstrated that the Ulva fasciata green algae can be considered as a source of bioactive ulvan.
本研究采用化学成分分析方法，结合红外、质谱和核磁共振光谱，确定了从紫叶绿海藻中提取的多糖的结构特征。结果表明，该多糖由两个主要的重复双糖单元组成，分别为硫酸脲酸3- A型(A3s)[→4]-β- d - glca -(1→4)-α- l - rha 3S-(1→]和B型(B3s)[→4]-α- lidoa -(1→4)-α- l - rha 3S(1→]。该多糖具有显著的体外抗氧化活性。本研究表明，筋膜藻是一种具有生物活性的绿藻。
{"title":"Structural Characteristics and Antioxidant Activities of Polysaccharide Extracted from Ulva fasciata Green Seaweed","authors":"C. Hang, Vo Mai Nhu Hieu, P. Trinh, Thanh Thi Thu Thuy, Quach Thi Minh Thu, Tran Nguyen Ha Vy, N. T. Thuan, T. T. Vân","doi":"10.25073/2588-1140/vnunst.5360","DOIUrl":"https://doi.org/10.25073/2588-1140/vnunst.5360","url":null,"abstract":"In this study, the structural characteristics of a polysaccharide extracted from the Ulva fasciata green seaweed were determined using the chemical composition analytical methods combined with IR, MS, and NMR spectra. The results showed that the polysaccharide consists of two major repeating disaccharide units designated as ulvanobiuronic acid 3-sulfate type A (A3s) [→4)-β-D-GlcA-(1 → 4)-α-L-Rha 3S-(1→] and type B (B3s) [→4)-α-LIdoA-(1 → 4)-α-L-Rha 3s(1→]. This kind of polysaccharide exhibited a significant in vitro antioxidant activity. This study demonstrated that the Ulva fasciata green algae can be considered as a source of bioactive ulvan.","PeriodicalId":23524,"journal":{"name":"VNU Journal of Science: Natural Sciences and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81066936","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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