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  • 1
    Online Resource
    Online Resource
    Fabrication and surface modification of PT nanowires for glucose detection
    Viet Nam National University Ho Chi Minh City ; 2013
    In:  Science and Technology Development Journal Vol. 16, No. 1 ( 2013-03-31), p. 26-36
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 16, No. 1 ( 2013-03-31), p. 26-36
    Abstract: In this paper we present a new fabrication technique that only uses conventional techniques of microtechnology such as microlithography, thin-film deposition and directional ion beam etching to makevery narrow, wafer-scale length platinum (Pt) nanowires, named deposition and etching under angles (DEA). Then fabricated Pt nanowires electrodes were modified by using several chemicals to immobilize glucose oxidase (GOD) enzyme for application in glucose detection. A cyclic voltammetry (CV) technique was used to determine glucose concentrations. The detection results showed that GOD was immobilized on all of the tested surfaces and the highest glucose detection sensitivity of 60μM was obtained when the Pt nanowires were modified by PVA. Moreover, the sensors also showed very high current response when the Pt nanowires were modified with the cysteamine SAM.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v16i1.1416
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2013
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  • 2
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    Online Resource
    Two new compounds from leaves of Bruguiera cylindrica (L.) Blume with the in vitro α-glucosidase inhibitory activity
    Viet Nam National University Ho Chi Minh City ; 2021
    In:  Science and Technology Development Journal Vol. 23, No. 4 ( 2021-01-12)
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 23, No. 4 ( 2021-01-12)
    Abstract: Introduction: Bruguiera cylindrica is one of the mangrove plants belonging to Bruguiera genus. This genus is characterized by the presence of a large number of compounds, but the research on bioactivities has not been investigated so far. In the present research, the α-glucosidase inhibitory activity, as well as chemical constituents of the ethyl acetate extract of this plant, were studied. Methods: The chemical structures of two new compounds were elucidated by spectroscopic and computational methods. Results: Two new compounds, benzobrugierol (1) and bruguierine (2), were isolated from leaves of Bruguiera cylindrica (L.) Blume, together with nine known ones, including lupeol (3), betulin (4), chrysoeriol (5), glut-5-ene-3-ol (6), cholesta-4-ene-3-one (7), 3α-(Z)-coumaroyllupeol (8), 3α-(E)-coumaroyllupeol (9), 3β-hydroxycholesta-5-ene-7-one (10) and β-sitosterol 3-O-β-D-glucopyranoside (11). Extracts and some isolated compounds were evaluated for α-glucosidase inhibitory activities. Conclusion: The results showed that most of the extracts and tested compounds exhibited activities better than the positive control acarbose, especially two new compounds 1 and 2 with their IC50 values of 17.9 ± 0.4 and 34.6 ± 0.7 (mg/mL), respectively.
    Type of Medium: Online Resource
    ISSN: 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v23i4.2457
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2021
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  • 3
    Online Resource
    Online Resource
    Similarities and differences between service and product brand images - Evidence from education service
    Viet Nam National University Ho Chi Minh City ; 2016
    In:  Science and Technology Development Journal Vol. 19, No. 2 ( 2016-06-30), p. 91-103
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 19, No. 2 ( 2016-06-30), p. 91-103
    Abstract: Since the 1990s, the study of service brands has begun and developed rapidly but still remains relatively limited as works were mostly inspired by research on product brands. While several studies point out the homogeneity between these two concepts, there are (substantially) different aspects in terms of brand attributes and the way that customers build brand image in their mind. This study reviews the dominant literature of brand image in the service sector and clarifies the similarities and differences between the service brand and product brand. Also, using qualitative methods, this study aims to find service brand attributes in the education sector. From the above analysis, the study provides further research on the synthesis of brand image in the service sector. Finally, new directions of research in the field are suggested.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v19i2.730
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2016
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  • 4
    Online Resource
    Online Resource
    Groundwater reserve and capacity of groundwater extraction for Ilmenite placer mining in Ninh Thuan province
    Viet Nam National University Ho Chi Minh City ; 2014
    In:  Science and Technology Development Journal Vol. 17, No. 3 ( 2014-09-30), p. 34-39
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 17, No. 3 ( 2014-09-30), p. 34-39
    Abstract: Mining ilmenite placer develops quickly along the coastal zone in the center area, Vietnam. In Ninh Thuan province, the mines are mostly using water for the exploitation. We simulated groundwater flow with uncertain parameters in order to answer if groundwater can supply a part of water demand for the exploitation of ilmenite by using GMS software. Unfortunately, as the results of simulation, groundwater is not enough to supply for ilmenite exploitation. The authors calculated the ilmenite reserves in several communes in Ninh Thuan and water demands. Comparison of water demands and ability of groundwater supply concludes that local government should make a sustainable strategy of water use to preserve groundwater.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v17i3.1459
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2014
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  • 5
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    Online Resource
    Develop a clean air action plan based on scientific data: a case of Ho Chi Minh city
    Viet Nam National University Ho Chi Minh City ; 2020
    In:  Science and Technology Development Journal - Natural Sciences Vol. 4, No. 1 ( 2020-12-20), p. first-
    Details
    In: Science and Technology Development Journal - Natural Sciences, Viet Nam National University Ho Chi Minh City, Vol. 4, No. 1 ( 2020-12-20), p. first-
    Abstract: Ho Chi Minh City (HCMC) has quickly become a modernized and industrialized city undergoing a rapid population growth affecting on the local environment, especially the air quality and human health. It's urgent need to have a Clean Air Action Plan (CAP) for HCMC. The aim of this research is to develop a clean air plan for HCMC based on scientific basis by integrating results of emissions inventory, air emssion loading capacties and results of the impact of air pollution on people's health. This research applied the Clean Air For Smaller City in ASEAN Region project (CASC) method of Germany to develop the CAP. Emission inventory resulted from the integration of two approaches of bottom-up and top-down. The results of simulation of air pollution dispersion and air emission loading capacities were from the TAPM-CTM model system. Method of calculating the impact of air pollution on the health of people in Ho Chi Minh City was based on BENMAP model theory. The results showed that the source of traffic accounts for the largest emissions of all pollutants, contributed respectively, 99%, 97%, 93%, 78%, 23%, 64% and 45% of total CO, NMVOC emissions, NOx, SO2, TSP, CH4, and PM2:5 of the whole HCMC. For some central areas, the city was no longer able to receive more emissions of CO and NOx. Assessing the impact of air pollution on health showed that the great impact of PM2:5 on public health accounted for 81.45% of the total deaths caused by all three pollutants ( PM2:5, SO2, NO2). Finally, a CAP was suggested with 13 proposals and 1 recommendation for reducing air pollution in HCMC for the period of 2020–2025. This is the first comprehensive study on CAP in Vietnam. This result supports government authorities to promulgate plans and actions to reduce emissions protecting human health and the environment for a sustainable development.
    Type of Medium: Online Resource
    ISSN: 2588-106X , 2588-106X
    URL: Article
    DOI: 10.32508/stdjns.v4i1.991
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2020
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  • 6
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    Online Resource
    Preparation of activated red mud and its application for removal of hydrogen sulfide in air
    Viet Nam National University Ho Chi Minh City ; 2020
    In:  Science & Technology Development Journal - Engineering and Technology Vol. 3, No. 2 ( 2020-07-03), p. First-
    Details
    In: Science & Technology Development Journal - Engineering and Technology, Viet Nam National University Ho Chi Minh City, Vol. 3, No. 2 ( 2020-07-03), p. First-
    Abstract: Red mud is a highly alkaline solid waste from the Bayer process for aluminum production. Red mud reservoirs are usually considered as a potential environmental risk. The treatment of red mud is costly due to the lack of an effective and economical treatment technology. On the other hand, the main components of red mud are Fe2O3, Al2O3, SiO2, and Na2O, which could be employed as a promising precursor for the preparation of various nanomaterials. In this study, we prepared activated red mud by thermal and acid treatment method and applied it for adsorption of H2S in air. The red mud was activated under different temperatures (i.e., 200, 400, 600, and 800 oC for 4 h), types of acid (i.e., H2SO4 and HCl), and acid concentrations (i.e., 0.5, 1.5, and 2.5 M). The produced materials were then applied for H2S removal in air with concentration of 90 – 110 mg/m3 using a fix-bed adsorption column test. Results showed that red mud activated at 800 oC and with 1.5 M H2SO4 solution had the highest adsorption capacity of 29.38 mg/g with an average removal efficiency of 80.2%. The effects of gas flow rate and initial H2S concentration were also investigated, and the highest removal capacity was achieved at an inlet concentration of 100 mg/m3 and flow rate of 1 L/min. Both Langmuir and Freundlich adsorption isotherms were employed for modelling the H2S adsorption by this material and the experimental result was more fitted with the Langmuir isotherm. The thermal desorption and recyclability test were also conducted for evaluating the practical application of activated red mud material and 200 oC was the suggested desorption temperature with 81.7% adsorption capacity recovery.
    Type of Medium: Online Resource
    ISSN: 2615-9872 , 2615-9872
    URL: Article
    DOI: 10.32508/stdjet.v3i2.474
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2020
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  • 7
    Online Resource
    Online Resource
    The influence of homogenization and storage time on the viability of Lactobacillus casei and Bifidobacterium bifidumin ice cream
    Viet Nam National University Ho Chi Minh City ; 2017
    In:  Science and Technology Development Journal Vol. 20, No. K1 ( 2017-03-31), p. 67-72
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 20, No. K1 ( 2017-03-31), p. 67-72
    Abstract: Bifidobacterium bifidum or Lactobacillus casei were added independently into ice cream with or without homogenization. The viability of probiotic bacteria during storage, in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) was investigated. The results showed that the viability of Bifidobacterium bifidum and Lactobacillus casei in ice cream samples was significantly decreased during 100 days of storage. The homogenization in ice cream processing was a significant effect on the survival of L.casei and B.bifidum during frozen storage time. In addition, frozen storage time affected the viability of these strain when incubating in SGF and SIF conditions. The longer storage time, the more sensitive probiotic in SGF and SIF condition. The result also indicated, in SGF condition, the difference between homogenization and non-homogenization samples was only statistically significant (p 〈 0,05) after 100 days of storage.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v20iK1.416
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2017
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  • 8
    Online Resource
    Online Resource
    Study on dose rate distribution inside diagnostic X-ray room by using MCNP5 code
    Viet Nam National University Ho Chi Minh City ; 2013
    In:  Science and Technology Development Journal Vol. 16, No. 4 ( 2013-12-31), p. 35-42
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 16, No. 4 ( 2013-12-31), p. 35-42
    Abstract: In this paper, the scattering influence on image quality and radiation safety because of changing room size was studied. To estimate the radiation safety in X-ray room, the exact determination of dose rate distribution inside the room and absorbed dose rate for patient is the first task. The authors simulated the dose rate distribution inside diagnostic X-ray room at Nhi Dong hospital with using MCNP5 code. The dependence of dose rate distribution on various peak voltages of X-ray tube was also investigated in this study
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v16i4.1594
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2013
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  • 9
    Online Resource
    Online Resource
    Synthesis of silica nanoparticles from rice husk ash
    Viet Nam National University Ho Chi Minh City ; 2018
    In:  Science and Technology Development Journal Vol. 20, No. K7 ( 2018-11-27), p. 50-54
    Details
    In: Science and Technology Development Journal, Viet Nam National University Ho Chi Minh City, Vol. 20, No. K7 ( 2018-11-27), p. 50-54
    Abstract: Silica nanoparticles (SiO2 NPs) were synthesized from rice husk ash (RHA) by chemical treatment and calcination. The size of SiO2 NPs evaluated by transmission electron microscope (TEM) was of 20 - 50 nm and the size distribution of SiO2 NPs measured by dynamic laser scattering (DLS) was of Gaussian mode. The X-ray diffraction (XRD) pattern with only one peak at 2θ ~ 220 confirmed the amorphous phase of SiO2 NPs. The Fourier transform infrared (FTIR) and energydispersive X-ray (EDX) spectra were also used to evaluate the functional groups and the purity of SiO2 NPs. The SiO2 NPs powder with high purity could be suitably produced by calcination of acid treated RHA at 7000C for 2h. The obtained SiO2 NPs product can be potentially used for numerous purposes of application, especially as filler in paints.
    Type of Medium: Online Resource
    ISSN: 1859-0128 , 1859-0128
    URL: Article
    DOI: 10.32508/stdj.v20iK7.1211
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2018
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  • 10
    Online Resource
    Online Resource
    Study of Curcumin Adsorption of Nano Fe-based Metal-Organic Framework
    Viet Nam National University Ho Chi Minh City ; 2020
    In:  Science and Technology Development Journal - Natural Sciences Vol. 4, No. 4 ( 2020-11-13), p. First-
    Details
    In: Science and Technology Development Journal - Natural Sciences, Viet Nam National University Ho Chi Minh City, Vol. 4, No. 4 ( 2020-11-13), p. First-
    Abstract: Highly porous and biocompatible nano metal-organic framework materials (NMOF) are increasingly being applied in biomedical fields, especially as pharmaceutical adsorbent materials. Curcumin, found in turmeric, is a widely common herb in Eastern which has recently used in many applications in supporting cancer treatment. In the synthesis of MOF materials, the use of surfactants allows to control the morphology, the process of crystal formation and development and particle size of the material. In this research, MIL-100 (Fe) nanomaterials were successfully synthesized at room temperature in the presence of polyvinylpyrrolidone surfactant (PVP) to control the nanoparticle size about 50 nm in size. The synthesized MOF structure and properties were analyzed by using characterization techniques, including powder X-ray diffraction (PXRD), fourier-transform infrared (FT-IR), thermal gravimetric analyses (TGA) and nitrogen isothermal adsorption-desorption at 77 K. The characterization results showed that MIL-100 (Fe) nanomaterials have high crystallinity, large surface area, and highly thermal stability. However, its particle size is very small, only about 50 nm. Curcumin adsorption studies exhibited that this material had the ability to adsorb curcumin with an adsorption capacity up to 64.36 mg g-1. Kinetic and mechanism studies revealed that curcumin adsorption followed the pseudo-second model. In addition, thermodynamic studies proved that this was a spontaneous and exothermic adsorption process.
    Type of Medium: Online Resource
    ISSN: 2588-106X , 2588-106X
    URL: Article
    DOI: 10.32508/stdjns.v4i4.927
    Language: Unknown
    Publisher: Viet Nam National University Ho Chi Minh City
    Publication Date: 2020
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