Pub Date : 2019-09-16DOI: 10.31276/vjste.61(3).25-32
Thanh T. Nguyen, Minh-Vy Huynh, Thanh-Hai Le, T. Pham
Breast cancer is a well-known health issue that has been a major focus for healthcare professionals for quite some time. Still, the most common noninvasive diagnostic tool - mammography - results in a high false positive rate along with risks of exposure to radiation. These disadvantages are magnified and become more severe when screenings are done repeatedly. To tackle this problem, we introduce a novel framework for uncomplicated diagnosis of breast cancer. Our method utilizes the analytical technique of Mueller matrix decomposition and Stokes vector polarimetry from a polarized light system consisting of a helium-neon laser (wavelength of 632.5 nm), a quarter-wave plate, polarizers, and a Stokes polarimeter. Thus, this technique introduces no radiation. We extracted nine optical parameters of a breast cancer cell line - BT474 - and determined the relationshipand separation power of these parameters to cancerous cells and healthy cells. Specifically, the samples were designed as a two-dimensional cellular model of malignant breast tumours that combined a range of four cell densities - 104, 105, 106, and 107 cells - per an area of 9 cm2.Nine optical parameters - orientation angle of linear birefringence (α), retardance or linear birefringence (β), optical rotation angle or circular birefringence (γ), orientation angle of linear dichroism (θd), linear dichroism (D), circular dichroism (R), degrees of linear depolarization (e1 and e2), and degree of circular depolarization (e3) - were extracted from a total of 40 samples using the polarized light system. The results revealed the positive correlations between three cell densities (104, 105, and 106) and the orientation angle of linear birefringence (R2 = 0.8038), linear birefringence (R2 = 0.8627), and linear dichroism (R2 = 0.9662). Meanwhile, both the orientation angle of linear dichroism and circular dichroism illustrated the negative correlation with that range of cell densities with R2 = 0.9983 and 0.9447, respectively. This proves that the optical parameters measured demonstrate significant association with the cells’ characteristics and thus, the proposed method could pave the way for an accessible diagnosis of breast cancer.
{"title":"Characterization of optical parameters of breast cancercell line - BT474 by polarimetry technique","authors":"Thanh T. Nguyen, Minh-Vy Huynh, Thanh-Hai Le, T. Pham","doi":"10.31276/vjste.61(3).25-32","DOIUrl":"https://doi.org/10.31276/vjste.61(3).25-32","url":null,"abstract":"Breast cancer is a well-known health issue that has been a major focus for healthcare professionals for quite some time. Still, the most common noninvasive diagnostic tool - mammography - results in a high false positive rate along with risks of exposure to radiation. These disadvantages are magnified and become more severe when screenings are done repeatedly. To tackle this problem, we introduce a novel framework for uncomplicated diagnosis of breast cancer. Our method utilizes the analytical technique of Mueller matrix decomposition and Stokes vector polarimetry from a polarized light system consisting of a helium-neon laser (wavelength of 632.5 nm), a quarter-wave plate, polarizers, and a Stokes polarimeter. Thus, this technique introduces no radiation. We extracted nine optical parameters of a breast cancer cell line - BT474 - and determined the relationshipand separation power of these parameters to cancerous cells and healthy cells. Specifically, the samples were designed as a two-dimensional cellular model of malignant breast tumours that combined a range of four cell densities - 104, 105, 106, and 107 cells - per an area of 9 cm2.Nine optical parameters - orientation angle of linear birefringence (α), retardance or linear birefringence (β), optical rotation angle or circular birefringence (γ), orientation angle of linear dichroism (θd), linear dichroism (D), circular dichroism (R), degrees of linear depolarization (e1 and e2), and degree of circular depolarization (e3) - were extracted from a total of 40 samples using the polarized light system. The results revealed the positive correlations between three cell densities (104, 105, and 106) and the orientation angle of linear birefringence (R2 = 0.8038), linear birefringence (R2 = 0.8627), and linear dichroism (R2 = 0.9662). Meanwhile, both the orientation angle of linear dichroism and circular dichroism illustrated the negative correlation with that range of cell densities with R2 = 0.9983 and 0.9447, respectively. This proves that the optical parameters measured demonstrate significant association with the cells’ characteristics and thus, the proposed method could pave the way for an accessible diagnosis of breast cancer.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73156196","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 : 2019-09-16DOI: 10.31276/vjste.61(3).16-24
Anh T. Sy, Vy T. H. Pham, T. Nguyen
In this study, the partitioning of fluoxetine, an antidepressant of selective serotonin reuptake inhibitor class into a mixture containing anionic and zwitterionic lipid vesicles was evaluated using second derivative spectrophotometry. The partition coefficients (Kp) of fluoxetine into the large unilamellar vesicles (LUVs) composed of zwitterionic 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) containing 0 mol%, 10 mol%, 20 mol%, and 30 mol% of anionic 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) were measured in HEPES buffer at pH 7.4. The result revealed that when more negatively charged lipids incorporated into the LUVs, the condensing effect on the binary phospholipid membrane impeded the partitioning of positively charged fluoxetine, resulting in the decrease in the Kpvalues. This study adds a deeper understanding of how antidepressant fluoxetine exerts its effect on anionic-containing biological membranes, shedding light onto drug delivery systems in the pharmaceutical field.
{"title":"Partitioning of fluoxetine into mixed lipid bilayer containing 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) and 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)","authors":"Anh T. Sy, Vy T. H. Pham, T. Nguyen","doi":"10.31276/vjste.61(3).16-24","DOIUrl":"https://doi.org/10.31276/vjste.61(3).16-24","url":null,"abstract":"In this study, the partitioning of fluoxetine, an antidepressant of selective serotonin reuptake inhibitor class into a mixture containing anionic and zwitterionic lipid vesicles was evaluated using second derivative spectrophotometry. The partition coefficients (Kp) of fluoxetine into the large unilamellar vesicles (LUVs) composed of zwitterionic 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) containing 0 mol%, 10 mol%, 20 mol%, and 30 mol% of anionic 1,2-dipalmitoyl-sn-glycero-3-phosphoglycerol (DPPG) were measured in HEPES buffer at pH 7.4. The result revealed that when more negatively charged lipids incorporated into the LUVs, the condensing effect on the binary phospholipid membrane impeded the partitioning of positively charged fluoxetine, resulting in the decrease in the Kpvalues. This study adds a deeper understanding of how antidepressant fluoxetine exerts its effect on anionic-containing biological membranes, shedding light onto drug delivery systems in the pharmaceutical field.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86175550","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 : 2019-09-16DOI: 10.31276/vjste.61(3).90-96
N. Nguyen, T. Tran, Van Der Heiden Dion, D. Dinh, P. Van
The research was conducted to assess the feasibility of the installation of a rainwater harvesting system for households facing difficulties in using tap water and groundwater for domestic purposes in a coastal area of the Vietnamese Mekong delta - the case study of the Vinh Chau town, Soc Trang province. Direct household interviews and literature review were executed to comprehend the current state of domestic water consumption. According to the research results, Vinh Chau was among the towns seeing moderate rainfall in the delta (~ 1,776 mm/year), and rainwater was used frequently by the local people. However, local households did not employ proper harvesting techniques, hence the harvested rainwater did not meet the required quality for domestic use. Additionally, difficulties in using tap water, groundwater, and surface water were notable. The quality of tap water was not suitable for household consumption because of the presence of aluminum, and the price was high relative to the household’s income. Salinization of surface and groundwater, as well as degradation in quantity of ground water, made water of acceptable quality scarce. The research results also indicated that the use of rainwater harvested by a proper system demonstrated a higher cost efficiency than that of other water resources. Therefore, the installation of a rainwater harvesting system for water supply should be encouraged in order to provide a safe and efficient alternative water source for domestic use, and to contribute to the relief of domestic water-related issues and pressure on groundwater extraction in the study area.
{"title":"The current state of domestic water consumption and the feasibility of implementing a rainwater harvesting system in the coastal zone of the Vietnamese Mekong delta: the case study of the Vinh Chau town, Soc Trang province","authors":"N. Nguyen, T. Tran, Van Der Heiden Dion, D. Dinh, P. Van","doi":"10.31276/vjste.61(3).90-96","DOIUrl":"https://doi.org/10.31276/vjste.61(3).90-96","url":null,"abstract":"The research was conducted to assess the feasibility of the installation of a rainwater harvesting system for households facing difficulties in using tap water and groundwater for domestic purposes in a coastal area of the Vietnamese Mekong delta - the case study of the Vinh Chau town, Soc Trang province. Direct household interviews and literature review were executed to comprehend the current state of domestic water consumption. According to the research results, Vinh Chau was among the towns seeing moderate rainfall in the delta (~ 1,776 mm/year), and rainwater was used frequently by the local people. However, local households did not employ proper harvesting techniques, hence the harvested rainwater did not meet the required quality for domestic use. Additionally, difficulties in using tap water, groundwater, and surface water were notable. The quality of tap water was not suitable for household consumption because of the presence of aluminum, and the price was high relative to the household’s income. Salinization of surface and groundwater, as well as degradation in quantity of ground water, made water of acceptable quality scarce. The research results also indicated that the use of rainwater harvested by a proper system demonstrated a higher cost efficiency than that of other water resources. Therefore, the installation of a rainwater harvesting system for water supply should be encouraged in order to provide a safe and efficient alternative water source for domestic use, and to contribute to the relief of domestic water-related issues and pressure on groundwater extraction in the study area.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"14 48 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80686160","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 : 2019-09-16DOI: 10.31276/vjste.61(3).45-51
Hoang Huong Diem, Bui Thi Van Khanh, H. Nhung, N. Liêm, T. Uyen
Exosomes represent an important mode of intercellular communication and play key roles in many physiological and pathological processes. Exosomes have hitherto exhibited their capacity to modulate biological activities through their carrying of functional molecules such as proteins, lipids, and genetic materials. In the current study, we investigated exosomes released by mature dendritic cells (mDCs) and umbilical cord-derived mesenchymal stem cells (UCMSCs) under Good Manufacturing Practice (GMP) conditions. Ultracentrifugation was used to isolate and purify the exosomes. Additionally, a transmission electron microscope (TEM) and immunoblotting were used to characterise exosomal morphology and markers. The preliminary results showed that both mDCs and UCMSCs secreted exosomes into GMP culture media. Exosomes exhibited a cup-shaped morphology and showed positive for CD63. Additionally, no difference was observed between mDC-derived exosomes and UCMSC-derived exosomes regarding marker expression or morphology. This data indicates the potential for further development of GMP exosomes for clinical application.
{"title":"Initial characterisation of exosomes released by umbilical cord-derivedmesenchymal stem cells and mature dendritic cells, under ‘Good Manufacturing Practice’ conditions","authors":"Hoang Huong Diem, Bui Thi Van Khanh, H. Nhung, N. Liêm, T. Uyen","doi":"10.31276/vjste.61(3).45-51","DOIUrl":"https://doi.org/10.31276/vjste.61(3).45-51","url":null,"abstract":"Exosomes represent an important mode of intercellular communication and play key roles in many physiological and pathological processes. Exosomes have hitherto exhibited their capacity to modulate biological activities through their carrying of functional molecules such as proteins, lipids, and genetic materials. In the current study, we investigated exosomes released by mature dendritic cells (mDCs) and umbilical cord-derived mesenchymal stem cells (UCMSCs) under Good Manufacturing Practice (GMP) conditions. Ultracentrifugation was used to isolate and purify the exosomes. Additionally, a transmission electron microscope (TEM) and immunoblotting were used to characterise exosomal morphology and markers. The preliminary results showed that both mDCs and UCMSCs secreted exosomes into GMP culture media. Exosomes exhibited a cup-shaped morphology and showed positive for CD63. Additionally, no difference was observed between mDC-derived exosomes and UCMSC-derived exosomes regarding marker expression or morphology. This data indicates the potential for further development of GMP exosomes for clinical application.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"124 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88022444","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 : 2019-09-16DOI: 10.31276/vjste.61(3).03-08
R. Omar
This paper reports on the synthesis and characterisation of Dy2O3-doped magnesium borate (MB) glasses containing different modifiers, lithium, calcium, and sodium oxides. Glasses composed of (70-z)B2O3-20Li2O; CaO; Na2O-10MgO-zDy2O3 (where 0.05≤z≤0.7 mol%) were prepared using the melt-quenching method. X-ray diffraction (XRD) pattern of the as-quenched samples verified their amorphous character. Differential thermal analysis (DTA) confirmed excellent glass-forming ability and thermal stability in the range of 0.60-0.67 and 0.18-0.82, respectively. The energy dispersive X-ray (EDX) spectra verified the precise elemental traces in the studied glasses. Furthermore, MB glasses doped with 0.1 mol% of Dy2O3 and modified with lithium oxide were found to have the best soft tissue equivalence (Zeff≈8.13). In short, the proposed MB glass system doped with dysprosium ions (Dy3+) was established as effective for accurate radiation detection in emergency situations.
{"title":"Synthesis and characterisation of dysprosium-doped borate glasses for use in radiation dosimeters","authors":"R. Omar","doi":"10.31276/vjste.61(3).03-08","DOIUrl":"https://doi.org/10.31276/vjste.61(3).03-08","url":null,"abstract":"This paper reports on the synthesis and characterisation of Dy2O3-doped magnesium borate (MB) glasses containing different modifiers, lithium, calcium, and sodium oxides. Glasses composed of (70-z)B2O3-20Li2O; CaO; Na2O-10MgO-zDy2O3 (where 0.05≤z≤0.7 mol%) were prepared using the melt-quenching method. X-ray diffraction (XRD) pattern of the as-quenched samples verified their amorphous character. Differential thermal analysis (DTA) confirmed excellent glass-forming ability and thermal stability in the range of 0.60-0.67 and 0.18-0.82, respectively. The energy dispersive X-ray (EDX) spectra verified the precise elemental traces in the studied glasses. Furthermore, MB glasses doped with 0.1 mol% of Dy2O3 and modified with lithium oxide were found to have the best soft tissue equivalence (Zeff≈8.13). In short, the proposed MB glass system doped with dysprosium ions (Dy3+) was established as effective for accurate radiation detection in emergency situations.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88068943","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 : 2019-06-30DOI: 10.31276/VJSTE.61(2).17-22
N. Hoc, N. Hoa, Tran Dinh Cuong, D. Thang, Hanoi Vietnam Communications
Taking the model of interstitial alloy AB with a body-centred cubic structure and the condition of absolute stability for the crystalline state, we derive analytic expression for the temperature of the limit of absolute stability for the crystalline state, the melting temperature, and the equation for the melting curve of this alloy using the statistical moment method. The results allow us to determine the melting temperature of alloy AB under pressure as well as at zero pressure. In limit cases, we obtain the melting theory of main metal A with a body-centred cubic structure. The theoretical results are numerically applied for alloys FeH, FeSi and FeC using different potentials.
{"title":"On the melting of interstitial alloys FeH, FeSi and FeC with a body-centred cubic structure under pressure","authors":"N. Hoc, N. Hoa, Tran Dinh Cuong, D. Thang, Hanoi Vietnam Communications","doi":"10.31276/VJSTE.61(2).17-22","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).17-22","url":null,"abstract":"Taking the model of interstitial alloy AB with a body-centred cubic structure and the condition of absolute stability for the crystalline state, we derive analytic expression for the temperature of the limit of absolute stability for the crystalline state, the melting temperature, and the equation for the melting curve of this alloy using the statistical moment method. The results allow us to determine the melting temperature of alloy AB under pressure as well as at zero pressure. In limit cases, we obtain the melting theory of main metal A with a body-centred cubic structure. The theoretical results are numerically applied for alloys FeH, FeSi and FeC using different potentials.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"62 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83228726","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 : 2019-06-13DOI: 10.31276/VJSTE.61(2).23-28
T. Nguyen, T. Nguyen, H. Tran, M. Nguyen, Huu Hieu Nguyen
In this research, graphene aerogel (GA) was fabricated by chemical reduction method, in which ethylenediamine (EDA) was used as a reducing and functionalising agent. The characterisation of GA was studied by density, field-emission scanning electron microscope, Brunauer-Emmett-Teller (BET) specific surface area, Fourier transform infrared spectroscopy, and X-ray diffraction. The results of the analysis showed that GA exhibits low density, ranging from 4-8 mg/cm3, high porosity, and BET specific surface area changes from 176 to 1845 m2/g. It was found that the suitable content of EDA on the synthesis of GA is 30 μl. The obtained GA was used as an adsorbent for removal of oils and methylene blue (MB) from aqueous solutions. The maximum adsorption capacities of GA for lubricant and crude oils are 160 g/g and 110 g/g respectively. The effecting factors including pH, contact time, and initial concentrations on the adsorption capacity of GA for MB were investigated. The adsorption process of MB onto GA followed the pseudo-second-order kinetic and well-fitted to Langmuir isotherm model. The maximum adsorption capacity for MB from linear Langmuir model was calculated to be 212.76 mg/g at pH 7. Accordingly, GA could be used as a potential adsorbent for removal of oils and MB from water.
{"title":"Synthesis and application of graphene aerogel as an adsorbent for water treatment","authors":"T. Nguyen, T. Nguyen, H. Tran, M. Nguyen, Huu Hieu Nguyen","doi":"10.31276/VJSTE.61(2).23-28","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).23-28","url":null,"abstract":"In this research, graphene aerogel (GA) was fabricated by chemical reduction method, in which ethylenediamine (EDA) was used as a reducing and functionalising agent. The characterisation of GA was studied by density, field-emission scanning electron microscope, Brunauer-Emmett-Teller (BET) specific surface area, Fourier transform infrared spectroscopy, and X-ray diffraction. The results of the analysis showed that GA exhibits low density, ranging from 4-8 mg/cm3, high porosity, and BET specific surface area changes from 176 to 1845 m2/g. It was found that the suitable content of EDA on the synthesis of GA is 30 μl. The obtained GA was used as an adsorbent for removal of oils and methylene blue (MB) from aqueous solutions. The maximum adsorption capacities of GA for lubricant and crude oils are 160 g/g and 110 g/g respectively. The effecting factors including pH, contact time, and initial concentrations on the adsorption capacity of GA for MB were investigated. The adsorption process of MB onto GA followed the pseudo-second-order kinetic and well-fitted to Langmuir isotherm model. The maximum adsorption capacity for MB from linear Langmuir model was calculated to be 212.76 mg/g at pH 7. Accordingly, GA could be used as a potential adsorbent for removal of oils and MB from water.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78248642","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 : 2019-06-13DOI: 10.31276/VJSTE.61(2).35-41
N. T. H. Diep, Thitinat Korsem, N. T. Cần, Walaiporn Phonphan, V. Minh
Aquaculture is an important economic activity in the coastal zone of Vietnam. Thanh Phu is one the coastal districts in Ben Tre province that rears brackish aquaculture. In recent years, farmers could not grow shrimp because of salinity intrusion and market price fluctuation. This study aims to determine aquaculture and fallow aquaculture pond distribution by using the three indices of NDVI (Normalized Difference Vegetation Index), MNDWI (Modified Normalized Difference Water Index) and NDBaI (Modified Difference Bareness Index) on Landsat 8 imagery. The results reveal that remote sensing can support the detection of aquaculture and fallow ponds with a high accuracy of 77%. The total aquaculture area is approximately 13,093.65 ha, of which the total fallow area is 581.49 ha (roughly 4.44% of the total aquaculture area). Moreover, the fallow ponds are randomly distributed in all four ecological zones and mostly in the fourth ecological region (about 73.92%). In the fourth region, saline concentration in water is from 20 to 30‰, which directly influences cultured shrimp farms. The results also indicate the spatial distribution of aquaculture ponds and ineffective aquaculture locations using Landsat 8 imagery via index image analysis. The findings support the local management’s decision making on further aquaculture planning.
{"title":"Determination of aquaculture distribution by using remote sensing technology in Thanh Phu district, Ben Tre province, Vietnam","authors":"N. T. H. Diep, Thitinat Korsem, N. T. Cần, Walaiporn Phonphan, V. Minh","doi":"10.31276/VJSTE.61(2).35-41","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).35-41","url":null,"abstract":"Aquaculture is an important economic activity in the coastal zone of Vietnam. Thanh Phu is one the coastal districts in Ben Tre province that rears brackish aquaculture. In recent years, farmers could not grow shrimp because of salinity intrusion and market price fluctuation. This study aims to determine aquaculture and fallow aquaculture pond distribution by using the three indices of NDVI (Normalized Difference Vegetation Index), MNDWI (Modified Normalized Difference Water Index) and NDBaI (Modified Difference Bareness Index) on Landsat 8 imagery. The results reveal that remote sensing can support the detection of aquaculture and fallow ponds with a high accuracy of 77%. The total aquaculture area is approximately 13,093.65 ha, of which the total fallow area is 581.49 ha (roughly 4.44% of the total aquaculture area). Moreover, the fallow ponds are randomly distributed in all four ecological zones and mostly in the fourth ecological region (about 73.92%). In the fourth region, saline concentration in water is from 20 to 30‰, which directly influences cultured shrimp farms. The results also indicate the spatial distribution of aquaculture ponds and ineffective aquaculture locations using Landsat 8 imagery via index image analysis. The findings support the local management’s decision making on further aquaculture planning.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88897461","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 : 2019-06-13DOI: 10.31276/VJSTE.61(2).79-83
T. To, Doan Thien Chi Nguyen, X. Le, Huu Huy Duong
This study aims to evaluate the differences between PM2.5, PAHs concentration, PAHs species, and their gas/particle partitioning in an urban background site as opposed to another background site. Saigon zoo was selected as a representative of the urban background site (UBS), and the Can Gio mangrove reserve was selected as the other background site (BS). PM2.5 and gas and particle-phase PAHs samples were collected at the UBS between March 2017 and February 2018, while the samples were collected at the BS for one week in the dry season (April) and in the rainy season (October). The results demonstrated that both PM2.5 and PAHs concentrations at the UBS were significantly higher than those at the BS. The PM2.5 concentration at the UBS and BS ranged from 13.3 to 67.6 μg/m3 and from 5.1 to 22.7 μg/m3, respectively. The total concentration of 14 PAHs at the UBS was 2.6 times greater than that at BS. Phenanthrene (Phe) was the dominant PAH in ambient air at both sites. Benzo[g,h,i] perylene (BghiP) and Indeno[1, 2, 3-cd]pyrene (InP), which indicate the traffic source, accounted for 3.6 and 3.3% of total PAHs at the UBS, while that at the BS accounted for 1.5 and 1.3%, respectively. This result suggested that vehicular emission strongly affected the UBS site.
{"title":"A comparison of PM2.5 and PAHs in ambient air between an urban background site and a background site in Ho Chi Minh city","authors":"T. To, Doan Thien Chi Nguyen, X. Le, Huu Huy Duong","doi":"10.31276/VJSTE.61(2).79-83","DOIUrl":"https://doi.org/10.31276/VJSTE.61(2).79-83","url":null,"abstract":"This study aims to evaluate the differences between PM2.5, PAHs concentration, PAHs species, and their gas/particle partitioning in an urban background site as opposed to another background site. Saigon zoo was selected as a representative of the urban background site (UBS), and the Can Gio mangrove reserve was selected as the other background site (BS). PM2.5 and gas and particle-phase PAHs samples were collected at the UBS between March 2017 and February 2018, while the samples were collected at the BS for one week in the dry season (April) and in the rainy season (October). The results demonstrated that both PM2.5 and PAHs concentrations at the UBS were significantly higher than those at the BS. The PM2.5 concentration at the UBS and BS ranged from 13.3 to 67.6 μg/m3 and from 5.1 to 22.7 μg/m3, respectively. The total concentration of 14 PAHs at the UBS was 2.6 times greater than that at BS. Phenanthrene (Phe) was the dominant PAH in ambient air at both sites. Benzo[g,h,i] perylene (BghiP) and Indeno[1, 2, 3-cd]pyrene (InP), which indicate the traffic source, accounted for 3.6 and 3.3% of total PAHs at the UBS, while that at the BS accounted for 1.5 and 1.3%, respectively. This result suggested that vehicular emission strongly affected the UBS site.","PeriodicalId":23548,"journal":{"name":"Vietnam Journal of Science, Technology and Engineering","volume":"65 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73108545","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 : 2019-06-13DOI: 10.31276/VJSTE.61(2).90-96
H. V. Cuong, D. Nam, Trinh Quang Toan
Understating hydro-climatological conditions in a transboundary is always challenging because of issues in sharing available data among riparian countries. The present study has explored the hydro-climatological drought conditions over Hong-Thai Binh river watershed (H-TBRW) based on the downscaled rainfall and reproduced streamflow by the state-of-the-art coupled regional hydroclimate model. The standardized precipitation index (SPI) and streamflow drought index (SDI) indicators are used to define the climatological and hydrological drought conditions, respectively. Both SPI and SDI are derived from the precipitation and streamflow data reproducibility for the H-TBRW during 1950-2015. The results demonstrate a slight increasing trend in both climatological and hydrological conditions. Over the H-TBRW, results reveal that the Da and Thao rivers strongly expect drought conditions; meanwhile, the remaining rivers are very likely to experience similar drought conditions as in the past.
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