Pub Date : 2023-12-15DOI: 10.15625/2525-2518/16991
Linh Nguyen Thi Dieu, Dung Nguyen Thi Kim, Thang Dam Xuan, Tham Do Quang
In this study, we reported a facile synthesis and the characterization of PMMA-grafted ZrO2 hybrid nanoparticles from original ZrO2 (oZrO2) nanoparticles. The synthesis process included of three steps: (i) modification of nano ZrO2 with a vinyl silane agent, (ii) graft copolymerization of methyl methacrylate (MMA) monomers and modified ZrO2 (mZrO2) nanoparticles, and (iii) extraction of homo PMMA to obtain the final product of PMMA-g-ZrO2 (gZrO2) nanoparticles. Fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA) of mZrO2, oZrO2, and gZrO2 indicated that the silane coupling agent was grafted onto oZrO2 nanoparticles. FTIR spectra of gZrO2 indicated PMMA had been successfully grafted onto the surface of ZrO2 nanoparticles. Using TGA method, the PMMA grafting content onto ZrO2 nanoparticles was evaluated as 9.03 wt.%. The electron microscopy (SEM) images of gZrO2, mZrO2, and oZrO2 indicated that their primary particle size and shape were almost unchanged after modification processes, their particle size was in the range from 50 nm to 140 nm. XRD analysis showed the monoclinic crystalline structure of three kinds of ZrO2 nanoparticles (nanocrystals). The organic gZrO2 nanoparticles can be a better candidate as an opacifier additive for polymer nanocomposites or acrylic bone cement.
{"title":"Synthesis and characterization of PMMA-grafted-ZrO2 hybrid nanoparticles","authors":"Linh Nguyen Thi Dieu, Dung Nguyen Thi Kim, Thang Dam Xuan, Tham Do Quang","doi":"10.15625/2525-2518/16991","DOIUrl":"https://doi.org/10.15625/2525-2518/16991","url":null,"abstract":"In this study, we reported a facile synthesis and the characterization of PMMA-grafted ZrO2 hybrid nanoparticles from original ZrO2 (oZrO2) nanoparticles. The synthesis process included of three steps: (i) modification of nano ZrO2 with a vinyl silane agent, (ii) graft copolymerization of methyl methacrylate (MMA) monomers and modified ZrO2 (mZrO2) nanoparticles, and (iii) extraction of homo PMMA to obtain the final product of PMMA-g-ZrO2 (gZrO2) nanoparticles. Fourier transform infrared (FTIR) spectra and thermogravimetric analysis (TGA) of mZrO2, oZrO2, and gZrO2 indicated that the silane coupling agent was grafted onto oZrO2 nanoparticles. FTIR spectra of gZrO2 indicated PMMA had been successfully grafted onto the surface of ZrO2 nanoparticles. Using TGA method, the PMMA grafting content onto ZrO2 nanoparticles was evaluated as 9.03 wt.%. The electron microscopy (SEM) images of gZrO2, mZrO2, and oZrO2 indicated that their primary particle size and shape were almost unchanged after modification processes, their particle size was in the range from 50 nm to 140 nm. XRD analysis showed the monoclinic crystalline structure of three kinds of ZrO2 nanoparticles (nanocrystals). The organic gZrO2 nanoparticles can be a better candidate as an opacifier additive for polymer nanocomposites or acrylic bone cement.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138997685","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: 10.15625/2525-2518/18516
Ngoc Tri Huynh Nguyen, Pham Huong Huyen Nguyen, Hoang Thien Khoi Nguyen, Khanh Son Nguyen
Scientists have been using microorganisms to improve soil strength and durability through a process called biocementation. This technique involves inducing mineral precipitation to form a cement-like material that enhances soil properties. Biocementation has been successful in various applications, including soil stabilization, erosion control, and groundwater remediation. Researchers are optimizing nutrient concentrations and ratios to create a favorable environment for microbial activity and promote efficient mineral formation. Different microorganisms have varying abilities to induce mineralization, and cycle treatments have shown promise in stimulating biomineralization processes. Biocementation is a sustainable and eco-friendly technique that can stabilize and immobilize contaminants in soil and groundwater, preventing the spread of pollutants. Despite these challenges, biocementation holds great potential for innovative soil improvement and environmental remediation. Recent studies, experiments, testing devices, and results from research groups in the world and Vietnam in recent years were reviewed to gain insight into this promising approach. Ongoing research aims to develop cost-efficient and sustainable methods for large-scale production and application of biocementing agents. Further research is needed to uncover the intricate mechanisms and identify optimal strategies for applications and environmental conditions.
{"title":"Eco-friendly method of biocementation for soil improvement and environmental remediation in the context of Viet Nam: a state-of-the-art review","authors":"Ngoc Tri Huynh Nguyen, Pham Huong Huyen Nguyen, Hoang Thien Khoi Nguyen, Khanh Son Nguyen","doi":"10.15625/2525-2518/18516","DOIUrl":"https://doi.org/10.15625/2525-2518/18516","url":null,"abstract":"Scientists have been using microorganisms to improve soil strength and durability through a process called biocementation. This technique involves inducing mineral precipitation to form a cement-like material that enhances soil properties. Biocementation has been successful in various applications, including soil stabilization, erosion control, and groundwater remediation. Researchers are optimizing nutrient concentrations and ratios to create a favorable environment for microbial activity and promote efficient mineral formation. Different microorganisms have varying abilities to induce mineralization, and cycle treatments have shown promise in stimulating biomineralization processes. Biocementation is a sustainable and eco-friendly technique that can stabilize and immobilize contaminants in soil and groundwater, preventing the spread of pollutants. Despite these challenges, biocementation holds great potential for innovative soil improvement and environmental remediation. Recent studies, experiments, testing devices, and results from research groups in the world and Vietnam in recent years were reviewed to gain insight into this promising approach. Ongoing research aims to develop cost-efficient and sustainable methods for large-scale production and application of biocementing agents. Further research is needed to uncover the intricate mechanisms and identify optimal strategies for applications and environmental conditions.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138997681","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: 10.15625/2525-2518/16746
Van So Nguyen, Anh Tuan Le
The rapid development of the areas of Notopterus chitala fish ponds in Hau Giang province in recent years has raised a question about greenhouse gas emissions, in the form of total carbon dioxide equivalents (CO2e). There are many parameters that affect greenhouse gas emissions in a fish pond, such as amount of feed, dissolved oxygen (DO), chemical oxygen demand (COD) in the water, pH, water temperature, windy velocity and sunlight reaching the pond surface. In this study, a System Thinking, Experimental Learning Laboratory with Animation, shortly called as Stella is applied as a visual programming language for system dynamics modelling in order to find the relationship between simulated CO2 and measured CO2 in Notopterus chitala fish pond. Three ponds were used for measuring average pH, temperature, feeds, DO, COD and phytoplankton inside the ponds while windy speed and light intensity data were collected from a Weather Station nearby. The results of model calibration and validation showed that the Stella 8.0 can be used as predictable tool for the change in time of CO2 emission during 240 days of fishing. Model can help fishing farmers to adjust the quantity of feeds and control the water quality in their Notopterus chitala fish ponds to reduce greenhouse gas emissions appropriately.
{"title":"Modelling carbon dioxide gas emission from Notopterus chitala fish ponds by stella software","authors":"Van So Nguyen, Anh Tuan Le","doi":"10.15625/2525-2518/16746","DOIUrl":"https://doi.org/10.15625/2525-2518/16746","url":null,"abstract":"The rapid development of the areas of Notopterus chitala fish ponds in Hau Giang province in recent years has raised a question about greenhouse gas emissions, in the form of total carbon dioxide equivalents (CO2e). There are many parameters that affect greenhouse gas emissions in a fish pond, such as amount of feed, dissolved oxygen (DO), chemical oxygen demand (COD) in the water, pH, water temperature, windy velocity and sunlight reaching the pond surface. In this study, a System Thinking, Experimental Learning Laboratory with Animation, shortly called as Stella is applied as a visual programming language for system dynamics modelling in order to find the relationship between simulated CO2 and measured CO2 in Notopterus chitala fish pond. Three ponds were used for measuring average pH, temperature, feeds, DO, COD and phytoplankton inside the ponds while windy speed and light intensity data were collected from a Weather Station nearby. The results of model calibration and validation showed that the Stella 8.0 can be used as predictable tool for the change in time of CO2 emission during 240 days of fishing. Model can help fishing farmers to adjust the quantity of feeds and control the water quality in their Notopterus chitala fish ponds to reduce greenhouse gas emissions appropriately.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139001111","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: 10.15625/2525-2518/17045
Hoang Trong Duc, Le Tran Bao Tran, Tran Ngoc Thao, C. V. Lanh, Nguyen Thi Thuy
In this work, the dispersion properties and nonlinear properties of circular photonic crystal fibers were improved by a combination of carbon tetrachloride infiltration into the core and modification of the air hole diameters d1 and d2 of rings in the cladding. The quantities such as dispersion, effective mode area, nonlinear coefficient, and low confinement are analyzed in detail. Based on the survey results, two photonic crystal fibers with optimal optical properties were proposed which are beneficial for supercontinuum generation. The first fiber with Ʌ = 1.0 µm, d1/Ʌ = 0.6, has an all-normal dispersion of –10.785 ps/nm.km at a pump wavelength of 0.985 µm. The high nonlinear coefficient of 581.795 W–1.km–1 and the low confinement loss of 3.904 dB/m are also achieved with this fiber. SC broadband under the influence of soliton is expected to be generated when using the second fiber (Ʌ = 2.0 µm, d1/Ʌ = 0.3) with flat and low anomalous dispersion at the pump wavelength of 1.3 µm.
{"title":"Optical properties of circular photonic crystal fibers filled with carbon tetrachloride","authors":"Hoang Trong Duc, Le Tran Bao Tran, Tran Ngoc Thao, C. V. Lanh, Nguyen Thi Thuy","doi":"10.15625/2525-2518/17045","DOIUrl":"https://doi.org/10.15625/2525-2518/17045","url":null,"abstract":"In this work, the dispersion properties and nonlinear properties of circular photonic crystal fibers were improved by a combination of carbon tetrachloride infiltration into the core and modification of the air hole diameters d1 and d2 of rings in the cladding. The quantities such as dispersion, effective mode area, nonlinear coefficient, and low confinement are analyzed in detail. Based on the survey results, two photonic crystal fibers with optimal optical properties were proposed which are beneficial for supercontinuum generation. The first fiber with Ʌ = 1.0 µm, d1/Ʌ = 0.6, has an all-normal dispersion of –10.785 ps/nm.km at a pump wavelength of 0.985 µm. The high nonlinear coefficient of 581.795 W–1.km–1 and the low confinement loss of 3.904 dB/m are also achieved with this fiber. SC broadband under the influence of soliton is expected to be generated when using the second fiber (Ʌ = 2.0 µm, d1/Ʌ = 0.3) with flat and low anomalous dispersion at the pump wavelength of 1.3 µm.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138995739","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 : 2023-11-20DOI: 10.15625/2525-2518/18867
Vu Thi Quynh Chi, Nguyen Viet Hiep, Le Thi My Hao, Nguyen Quang Hai, Do Thi Kim Anh, Huong Pham, Than Van Hau, Nguyen Cong Viet, Ngo Thi Xinh, Nguyen Thi Loi, Bui Dang Thanh
Root endophytic and rhizosphere bacteria play a significant role in enhancing plant tolerance and promoting growth by producing 1-aminocyclopropane-1-carboxylate (ACC) deaminase, indole-3-acetic acid (IAA), and siderophore. These bacteria have been isolated and screened from 45 plants’ roots and rhizosphere soil samples of 19 types of plants which are growing on 8 floating islands in Spratley Islands, Viet Nam. In which, 3 root endophytic bacteria strains were selected and identified to be Agrobacterium tumefaciens, Pseudomonas plecoglossicida, and Klebsiella aerogenes from roots of Scaevola taccada, Barringtonia asiatica (L.) Kurz, and Carica papaya, respectively. Correspondingly, 3 rhizosphere bacteria strains were selected and identified to be Bacillus velezensis, Bacillus aryabhattai, and Bacillus velezensis from rhizosphere soils of Canavalia maritima (Aubt) Thouars (C. obtusifolia DC.), Cucumis sativus, Heliotropium foertherianum, respectively. These strains were found could increase the germination rate of Brassica juncea’s seeds and 20-day-old fresh biomass, compared to the control treatment in the same condition of 10‰ saline watering. When these bacterial strains were combined as an inoculant, they indicated the same result on coral sand. Thus, the addition of selected endophytic and rhizosphere bacteria is efficient in improving the coral sand environment to enhance food crops’ development in the Spratly Islands.
{"title":"Assessment of the role of ACC deaminase, IAA, and siderophore-producing bacteria isolated from Spratly Islands on the growth of Brassica juncea on the coral sand","authors":"Vu Thi Quynh Chi, Nguyen Viet Hiep, Le Thi My Hao, Nguyen Quang Hai, Do Thi Kim Anh, Huong Pham, Than Van Hau, Nguyen Cong Viet, Ngo Thi Xinh, Nguyen Thi Loi, Bui Dang Thanh","doi":"10.15625/2525-2518/18867","DOIUrl":"https://doi.org/10.15625/2525-2518/18867","url":null,"abstract":"Root endophytic and rhizosphere bacteria play a significant role in enhancing plant tolerance and promoting growth by producing 1-aminocyclopropane-1-carboxylate (ACC) deaminase, indole-3-acetic acid (IAA), and siderophore. These bacteria have been isolated and screened from 45 plants’ roots and rhizosphere soil samples of 19 types of plants which are growing on 8 floating islands in Spratley Islands, Viet Nam. In which, 3 root endophytic bacteria strains were selected and identified to be Agrobacterium tumefaciens, Pseudomonas plecoglossicida, and Klebsiella aerogenes from roots of Scaevola taccada, Barringtonia asiatica (L.) Kurz, and Carica papaya, respectively. Correspondingly, 3 rhizosphere bacteria strains were selected and identified to be Bacillus velezensis, Bacillus aryabhattai, and Bacillus velezensis from rhizosphere soils of Canavalia maritima (Aubt) Thouars (C. obtusifolia DC.), Cucumis sativus, Heliotropium foertherianum, respectively. These strains were found could increase the germination rate of Brassica juncea’s seeds and 20-day-old fresh biomass, compared to the control treatment in the same condition of 10‰ saline watering. When these bacterial strains were combined as an inoculant, they indicated the same result on coral sand. Thus, the addition of selected endophytic and rhizosphere bacteria is efficient in improving the coral sand environment to enhance food crops’ development in the Spratly Islands.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139257411","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}
Two heterotrophic nitrifying bacterial strains, D2 and D7 were isolated from an activated sludge of sponges in a laboratory-scale downflow hanging sponge reactor. Both strains exhibited efficient ammonium removal ability over a wide range of ammonium loads. At the initial concentration of 100 mg/L, NH4+-N was completely degraded within 20 h by both strains. When the initial concentration was increased to 200 mg/L, the NH4+-N removal efficiency was 99.6 % within 20 h by the strain D2 and 61.3 % by the strain D7. In natural rubber processing wastewater, the ammonium removal efficiencies of strain D2 and D7 were 38 % and 99 % with the initial N-NH4+ concentration of 280 and 380 mg/L after 88 h, respectively. The 16S rRNA gene sequence of D2 and D7 showed the highest similarity to the Pseudomonas aeruginosa and Glutamicibacter nicotianae, respectively. This is the first report to demonstrate the ability to remove ammonium in NRPW by heterotrophic nitrifying bacteria isolated from activated sludge in DHS reactor.
{"title":"Heterotrophic nitrifying bacteria from activated sludge in DHS reactor for ammonium removal of natural rubber processing wastewater treatment","authors":"Tran Minh Duc, Phan Thi Thanh Thuy, Nguyen Thi Huyen, Nguyen Lan Huong","doi":"10.15625/2525-2518/17141","DOIUrl":"https://doi.org/10.15625/2525-2518/17141","url":null,"abstract":"Two heterotrophic nitrifying bacterial strains, D2 and D7 were isolated from an activated sludge of sponges in a laboratory-scale downflow hanging sponge reactor. Both strains exhibited efficient ammonium removal ability over a wide range of ammonium loads. At the initial concentration of 100 mg/L, NH4+-N was completely degraded within 20 h by both strains. When the initial concentration was increased to 200 mg/L, the NH4+-N removal efficiency was 99.6 % within 20 h by the strain D2 and 61.3 % by the strain D7. In natural rubber processing wastewater, the ammonium removal efficiencies of strain D2 and D7 were 38 % and 99 % with the initial N-NH4+ concentration of 280 and 380 mg/L after 88 h, respectively. The 16S rRNA gene sequence of D2 and D7 showed the highest similarity to the Pseudomonas aeruginosa and Glutamicibacter nicotianae, respectively. This is the first report to demonstrate the ability to remove ammonium in NRPW by heterotrophic nitrifying bacteria isolated from activated sludge in DHS reactor.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139316479","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: 10.15625/2525-2518/17426
Ngoc Khanh Pham, Katarina Bauerova, Nguyen Manh Cuong
The liver is a major organ of the human and animal body, playing an important role in metabolism, detoxification and immunomodulation. When liver tissue is damaged, liver function will decrease, leading to liver diseases such as liver fibrosis, cirrhosis, and liver cancer. Medicinal plants and natural products have provided a source of new drug candidates for the prevention and treatment of liver diseases. This review is based on scientific publications on Vietnamese plants investigated for their hepatoprotective activity during the period from 1998 to 2022. 51 medicinal plants, 38 phytoconstituents, and 8 hepatoprotective herbal formulations of Vietnamese-origin have been reported to protect the liver from the harmful effects induced by hepatotoxins, typically CCl4 or paracetamol. Each plant's information, including its botanical name, family, part of the plant used, local name, chemical constituents, extracts or fractions used, dosage, model used, parameters obtained, histopathology, and results of hepatoprotective studies, is displayed. Also discussed is the possible mechanism of action of these hepatoprotective plants.
{"title":"Studies on hepatoprotective effects of Vietnamese medicinal plants","authors":"Ngoc Khanh Pham, Katarina Bauerova, Nguyen Manh Cuong","doi":"10.15625/2525-2518/17426","DOIUrl":"https://doi.org/10.15625/2525-2518/17426","url":null,"abstract":"The liver is a major organ of the human and animal body, playing an important role in metabolism, detoxification and immunomodulation. When liver tissue is damaged, liver function will decrease, leading to liver diseases such as liver fibrosis, cirrhosis, and liver cancer. Medicinal plants and natural products have provided a source of new drug candidates for the prevention and treatment of liver diseases. This review is based on scientific publications on Vietnamese plants investigated for their hepatoprotective activity during the period from 1998 to 2022. 51 medicinal plants, 38 phytoconstituents, and 8 hepatoprotective herbal formulations of Vietnamese-origin have been reported to protect the liver from the harmful effects induced by hepatotoxins, typically CCl4 or paracetamol. Each plant's information, including its botanical name, family, part of the plant used, local name, chemical constituents, extracts or fractions used, dosage, model used, parameters obtained, histopathology, and results of hepatoprotective studies, is displayed. Also discussed is the possible mechanism of action of these hepatoprotective plants.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139315991","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: 10.15625/2525-2518/17346
B. Gogoi, K. J. Tamuli, Snigdha Saikia, Neipihoi Lhouvum, M. Bordoloi, Hemanta K. Sarma
Cinnamomum bejolghota (Buch.-Ham.) Sweetisa traditional anthelmintic and cardiotonic medicinal plant. The essential oil extracted from the bark of C. bejolghota was characterized by gas chromatography-mass spectrometry and 28 constituents were identified. Monoterpenoids were found to be dominating chemical constituents with α-terpineol (18.57 %) as the major component of the essential oil. The antioxidant activity of the essential oil was evaluated by DPPH radical, β-carotene bleaching and reducing power assay methods. The essential oil showed in-vitro dose-response hindering activity against angiotensin-converting enzyme with an IC50 value of 33.43 ± 0.46 µg/mL.The essential oil also exhibited potent anthelmintic property in-vitro against Caenorhabditis elegans with an ED50value of 80.53 ± 3.57 µg/mLin adult mortality assay. The inhibitory activity of essential oil against larval development assay showed an ED50value of 72.40 ± 2.68 µg/mL against C. elegans larva. Further, the egg hatching assay using C. eleganseggs demonstrated an ED50 value of 68.27 ± 3.51 µg/mL with this essential oil. Thus, the ethnomedicinal claim has been validated for the bark essential oil, which provides an excellent scope for the development of the C. bejolghota bark essential oil as novel herbal antihypertensive and anthelmintic agents.
{"title":"Antioxidant, angiotensin converting enzyme inhibitory and anthelmintic activities of bark essential oil of Cinnamomum bejolghota (Buch.-Ham.) Sweet from North East India","authors":"B. Gogoi, K. J. Tamuli, Snigdha Saikia, Neipihoi Lhouvum, M. Bordoloi, Hemanta K. Sarma","doi":"10.15625/2525-2518/17346","DOIUrl":"https://doi.org/10.15625/2525-2518/17346","url":null,"abstract":"Cinnamomum bejolghota (Buch.-Ham.) Sweetisa traditional anthelmintic and cardiotonic medicinal plant. The essential oil extracted from the bark of C. bejolghota was characterized by gas chromatography-mass spectrometry and 28 constituents were identified. Monoterpenoids were found to be dominating chemical constituents with α-terpineol (18.57 %) as the major component of the essential oil. The antioxidant activity of the essential oil was evaluated by DPPH radical, β-carotene bleaching and reducing power assay methods. The essential oil showed in-vitro dose-response hindering activity against angiotensin-converting enzyme with an IC50 value of 33.43 ± 0.46 µg/mL.The essential oil also exhibited potent anthelmintic property in-vitro against Caenorhabditis elegans with an ED50value of 80.53 ± 3.57 µg/mLin adult mortality assay. The inhibitory activity of essential oil against larval development assay showed an ED50value of 72.40 ± 2.68 µg/mL against C. elegans larva. Further, the egg hatching assay using C. eleganseggs demonstrated an ED50 value of 68.27 ± 3.51 µg/mL with this essential oil. Thus, the ethnomedicinal claim has been validated for the bark essential oil, which provides an excellent scope for the development of the C. bejolghota bark essential oil as novel herbal antihypertensive and anthelmintic agents.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139316163","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: 10.15625/2525-2518/18456
Binh Hai Hoang, V. S. Lo, B. Tran, T. T. Truong
This paper investigates fracture mechanics in particle-reinforced composites by using the extended finite element method enhanced by the consecutive-interpolation quadrilateral element. These composite materials have discontinuous boundaries such as cracks, voids, holes, and soft inclusions. And the extended consecutive-interpolation quadrilateral element (XCQ4) is employed to model these boundaries in two-dimensional linear elastic deformation problems. XCQ4 combines the enrichment functions in the traditional extended finite element method with the consecutive interpolation on a 4-node quadrilateral element. This element uses both nodal values and averaged nodal gradients as interpolated conditions. In fracture analysis, the stress intensity factors (SIFs) are important parameters that must be defined. In this study, the values of SIFs at the crack tips are evaluated with the help of the interaction integrals approach. The obtained numerical results are compared with other reliable results showing high accuracy and convergence rate of the XCQ4 element.
{"title":"Fracture analysis in 2D plane strain problems for composite materials containing hard inclusions and voids using an extended consecutive-interpolation quadrilateral element","authors":"Binh Hai Hoang, V. S. Lo, B. Tran, T. T. Truong","doi":"10.15625/2525-2518/18456","DOIUrl":"https://doi.org/10.15625/2525-2518/18456","url":null,"abstract":"This paper investigates fracture mechanics in particle-reinforced composites by using the extended finite element method enhanced by the consecutive-interpolation quadrilateral element. These composite materials have discontinuous boundaries such as cracks, voids, holes, and soft inclusions. And the extended consecutive-interpolation quadrilateral element (XCQ4) is employed to model these boundaries in two-dimensional linear elastic deformation problems. XCQ4 combines the enrichment functions in the traditional extended finite element method with the consecutive interpolation on a 4-node quadrilateral element. This element uses both nodal values and averaged nodal gradients as interpolated conditions. In fracture analysis, the stress intensity factors (SIFs) are important parameters that must be defined. In this study, the values of SIFs at the crack tips are evaluated with the help of the interaction integrals approach. The obtained numerical results are compared with other reliable results showing high accuracy and convergence rate of the XCQ4 element.","PeriodicalId":23553,"journal":{"name":"Vietnam Journal of Science and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139315942","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: 10.15625/2525-2518/17619
Nguyen Danh, Truong, Nguyen Van Quynh
We used the molecular dynamic finite element method with Stillinger-Weber potential to study the mechanical behavior of monolayer 1H-type nickel ditelluride (1H-NiTe2) sheets under uniaxial tension. As the size of the pristine 1H-NiTe2 sheet increases, the Young’s modulus in the armchair direction increases by 6.2 %, while that in the zigzag one decreases by 6.0 %. Both tend to be size-independent in larger sheets and approach the same value at around 54 N/m. The ultimate stress in the armchair direction remains almost unchanged but that in the zigzag one reduces by about 9.5 % as the size inclines. Besides the influence of size, our results show that single vacancy defects strongly affect the ultimate stress and strain while having no effect on Young’s modulus and Poisson’s ratio. When a Te atom is missing at the sheet’s center, the ultimate stress in the armchair direction is reduced by 11.7 %, while a decrease of 16.0 % is caused by a Ni atom vacancy
我们利用分子动力学有限元法和 Stillinger-Weber 电位研究了单层 1H 型二碲化镍（1H-NiTe2）薄片在单轴拉伸下的力学行为。随着原始 1H-NiTe2 片材尺寸的增大，扶手方向的杨氏模量增加了 6.2%，而之字形方向的杨氏模量降低了 6.0%。在较大的薄片中，二者都趋向于与尺寸无关，并在 54 N/m 左右接近相同的值。扶手方向的极限应力几乎保持不变，但人字形方向的极限应力则随着尺寸的增大而减小约 9.5%。除了尺寸的影响外，我们的结果还表明，单个空位缺陷对极限应力和应变有很大影响，而对杨氏模量和泊松比没有影响。当薄片中心缺少一个 Te 原子时，扶手方向的极限应力降低了 11.7%，而一个 Ni 原子空位则导致极限应力降低了 16.0%。
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