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Ngoc Kim Bui, Hieu Trung Pham, Minh Pham, Phuc Duc Le
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i2.962

Metacarbonates located in Sa Thay, Kon Tum massif are distributed in ultramafic marble assemblage from Kham Duc (NP-e1kđ) complex.The main rock-formingminerals arecalcite and dolomite (40÷85%), olivine (5÷20%), pyroxene (5÷15%), and serpentine (5÷25%). Accessory minerals aretalc and epidote. Chemical composition of pyroxene in metacarbonate was determined by EPMA method: the composition of pyroxene is diopsite (Wo49.5 En50.1Fs0.4 to Wo50.8En48.9Fs0.2). The rim of pyroxene grains generally have higher wollastonite than core(49.9÷50.8%).Metacarbonates originated from metamorphic sources with three main stages: regional metamorphism, superimposed metamorphismand hydrothermal metamorphism stages. With each stage, they have different color characteristicsto create a variety of color. Metacarbonateshave quality characteristicsofcolor, durability, pattern, diversity, and low radioactivity. These make the metacarbonates suitable for gemstone applications.
Tuan Hoang Nguyen, Truong Thanh Canh
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.939

The purpose of this study is to analyze the trend of precipitation change in Ninh Thuan province in the context of Climate Change. In this study, the authors used precipitation data at rain gauges with a minimum duration of 24 years and a maximum of 36 years. The main method was used in this study is the non-parametric method, namely Mann-Kendall analysis and the Theil-Sen slope. The research was conducted under the support of ProULC 5.1 and MAKESEN 1.0 software. The results showed that annual rainfall in Ninh Thuan province tended to increase in the time series of observation. Specifically, the downward trend of rainfall was mainly in March and increased from July to November. Along with that, through the index regarding the trend of increase and decrease of rainfall, the study also showed a prediction of the trend of increasing rainfall for the area. Forecast results of 2035 rainfall in Ninh Thuan the highest the increase is expected 7.7% and in 2050 is 13.8%. The study results have reflected the actual situation of rainfall change in the context of climate change with the stations having statistical significance (p
Editorial Office
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 921-924; doi:10.32508/stdjns.v4i4.1004

The editorial team greatly appreciates the reviewers who have dedicated their considerable time and expertise to the journal’s rigorous editorial process over the past 12 months, regardless of whether the papers are finally published or not. The editors would like to express their sincere gratitude to the following reviewers for their generous contribution in 2020.
Vu Huynh Tan, Quyen Pham My, Luan Nguyen The, Trang Huynh Thi Thien
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.963

Zinc oxide (ZnO) material possesses various morphologies which have given ZnO many fascinating applications in practice. Thus, the controlled synthesis of morphology and size of ZnO microstructures has attracted great interest. Many synthetic methods exhibited their effectiveness in producing pure ZnO, and the hydrothermal synthesis expresses its own considerable advantages for controlling the morphology of ZnO with low particle-size distribution. Moreover, the hydrothermal synthesis can be performed under mild condition rather than the conventional harsh ceramic method. In this work, we performed hydrothermal synthesis by altering different initial seeds by pre-treating of Zinc acetate solution prior to hydrothermal action. Characterization methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and Infrared (IR) spectroscopy were used to determine the morphology and surface functional groups of ZnO final products. Firstly, we processed the pretreatment of Zinc acetate solution by annealing it at 90 ◦C for 1h before putting the solution into autoclave together with NH3 solution for hydrothermal synthesis (this process is called as two-step hydrothermal synthesis). Secondly, the reaction temperatures (120 ◦C, 150 ◦C, 180 ◦C) were investigated to provide the role of temperature synthesis in controlling size and shape of ZnO, and at 150 ◦C, ZnO particles were formed with reasonable uniform morphology. Finally, we examined the effects of initial seeds by pre-treating Zinc acetate solution with H2O2, or, the initial seeds change from only Zn(OH)2 (without H2O2) to mutual existence of Zn(OH)2 and ZnO2 (with H2O2). In this case, ZnO Wurtzite phase was obtained with 100% purity at 180 ◦C, or at higher temperature than other samples whose ZnO Wurtzite phase was formed at only 150 ◦C. The results show that the nature of initial seeds greatly impact not only on the shape and size, but also on the surface functional groups of ZnO final product.
Lam Anh Le Viet, Thi Xuan Thi Luu, Tien Khoa Khoa Le
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.942

In order to synthesize p-hydroxybenzaldehyde from p-hydroxybenzyl alcohol under oxygen atmosphere, we prepared the new heterogeneous catalysts based on manganese oxides by in-situ growth method at different pH values. The crystal structure, phase composition, morphology, and surface groups of catalysts were characterized by powder X-ray diffraction, field emission electron scanning microscopy and Fourier transform infrared spectroscopy. According to the experimental results, the solution pH used for the preparation of the catalysts strongly affected their properties and their catalytic activities. When the pH was increased from 2 to 4, the a-Mn2O3 content increased with the dominant presence of the rod-like particles. The quantity of Mn on the surface also enhanced which might improve the conversion of p-hydroxybenzyl alcohol while maintaining the high selectivity to p-hydroxybenzaldehyde (about 70%). However, when the pH was highr than 4, the quantity of rod-like particles,a-Mn2O3 and surface Mn species decreased which lowered the catalytic activity.
Võ Thị Ngọc Giào, Tuyên Thi Kim Huynh, Phạm Thanh Liêm, Lê Minh Kha, Lê Mỹ Loan Phụng
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.964

Electrolytes play an important role in the battery components it determines the electrochemical window or the working potential region of the battery according to the LUMO and HOMO energy levels and reflects its thermodynamic stability when contacting with the electrode materials. The choice of the electrolyte affects significantly the specific energy, safety, cycle life, storage performance, or operating conditions of batteries. Besides, the electrolytes could be perfectly improved its performance within the addition of some essential additives, which also help to increase the performance of the battery. In this study, the effects of NaPF6, NaClO4, NaOTf, NaFSI, and NaTFSI salts on the hard carbon anode performance were investigated in the carbonate ester solvents including EC:DMC:PC (1:1:1) of 1 M salt concentration without and with additives FEC, VC, and Py13. The compatibility hard carbon electrode-electrolyte systems were investigated for their electrochemical performance by using Galvanostatic cycling with potential limitation, Cyclic voltammetry, and electrochemical impedance spectroscopy in coin-cell type. Among the studied electrolytes, the electrolyte EC:DMC:PC (1:1:1) + 1 M NaOTf exhibited the best electrochemical performance. The specific capacity was above 246 mAh/g after 100 cycles and the Coulombic efficiency higher than 99.6%.
Dat Ngoc Xuan Mai, Lua Thi Xuan Danh, Huy Dinh Minh Dang, Ha Van Nguyen, Hanh Thi Kieu Ta, Tan Le Hoang Doan, Tri Minh Le, Thang Bach Phan
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.933

Mesoporous silica nanoparticles (MSNs) are used as drug delivery materials because of their outstanding features such as large surface area, easy synthesis and high biocompability. In this study, inorganic mesoporous nanosilica material, MCM-41, was synthesized by sol-gel hydrothermal method using tetraethyl orthosilicate precursor (TEOS). The material structure and composition were analyzed by X-ray power diffraction (P-XRD), N2 adsorption isotherm, thermalgravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FT-IR). Its morphology was examined by scanning electron microscopy (SEM) and transmission electron microscope (TEM). The results showed that synthesized MCM-41 has a spherical shape, homogeneous with an average size of 100 nm. The specific surface area is 845 m2 g􀀀1, the pore size is approximately 35 Å. It has high thermal stability until 800oC. FT-IR result showed the formation of the Si-O-Si bond in the structure. The adenosine loading capacity of MCM-41 was investigated based on the influence of loading factors including adenosine concentration, time, solvent, and temperature. The kinetics and thermodynamics of the adsorption processes were also studied. The adenosine loading ability on MCM-41 is significant high, approximately 1699 mg g􀀀1. The kinetic and thermodynamic results showed that the drug adsorbed of MCM-41 occurred with fast rate and spontaneously. Moreover, the release profile of adenosine proved that the drug release process occurred quickly which is suitable for application in acute disease treatment.
, Tran Thi Thanh Van, Lê Thuy Thanh Giang
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.913

In our study, hexagonal-NaYF4: Eu3+ nanoparticles were synthesized by the solvothermal method at 180◦C for 24 hours. The typical vibrational spectrum showed the appearance of characteristic organic modes of oleic acid in the sample. The presence of elements such as Na, Y, F and Eu was indicated in the energy-dispersive X-ray spectroscopy (EDX). X-ray diffraction (XRD) patterns revealed that the NaYF4 host possessed the hexagonal structure when the doping contents below 5 mol%. At the Eu3+ amount of 10 mol%, the XRD appeared additional peaks of cubic phase of NaYF4 host. Both XRD and TEM data showed that the crystal sizes increase slightly as a function of Eu3+ doping concentration. Under an excitation at 395 nm, photoluminescence (PL) spectra revealed that the ratio of emission intensity between orange and red were controlled by changing the doping concentration. The optimal doping concentration was about 7 mol% for achieving the highest emission intensity. Moreover, PL data also demonstrated that a part of ions Eu3+ could occupy at Y3+ sites in the crystal structure of NaYF4. Because of their outstanding luminescent properties, NaYF4:Eu nanoparticles would the potential material for applications in biomedical medicine, optoelectronics.
Tuấn Anh Đào, Kiều Loan Phan Thị, Tuấn Hùng Lê Vũ, Hữu Kế Nguyễn
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.905

In this paper, we present a fabrication process of high crystallinity CZTSSe absorber layer. The CZTS structure is firstly prepared by spin-coating method, and then the film is converted into CZTSSe via selenization process using graphite box and tube furnace. The Se powder has been loaded into graphite box and used as source of selenizing vapors. Keeping the annealing temperature as constant, the structural, optical, electrical properties, and composition of CZTSSe thin films are investigated by changing the annealing time. X-ray diffraction revealed that these thin films are high crystallinity and strong preferential orientation along the (112) direction. The Raman spectra show the presence of the kesterite CZT Se phase which confirm the linkage of Se in structure. The band gaps (Eg) of the CZT Se thin films varied from 1,19 to 1.62 eV depend on the selenization times. At optimal annealing times, the p-type CZTSSe film has bandgap energy, hole concentration, and resistivity of 1,19 eV, 2,68 x 1019 cm-3 and 0,86Ω.cm respectively which are suitable for photovoltaic application.
, Cao Huu Tien, Diem Mai Thi Tran
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.967

Current bone regeneration surgeries focus on regenerating damaged bone tissue structures rather than replacing them. Bone-derived hydroxyapatite (HAP) is a natural bone component with good bone resilience, emerging and a promising bone graft material. Factors in the synthesis process are very important to the properties of hydroxyapatite. The purpose of this study is to assess the effect of three different furnaced temperatures on the size and phase purity of the HA crystal. The research consists of the following two stages: after combining physical and chemical methods in the first period to eliminate most of the organic components; bones continue to be heated at temperatures of 600oC, 700oC and 800oC to create the various size of HA crystals in bone particles. Product composition and size of HA crystal are determined by TGA, XRD, FTIR, SEM, EDX methods. The results show that crystal size and phase purity can be controlled and increased with the temperature. In particular, the HA crystal size did not change significantly in the range of 600◦C but increased 10-times above 700◦C. Single crystal HA is expected to form in the range of 600 - 700◦C. After the sample was heated to 600◦C, the organic compounds such as blood and bone marrow were completely burned. In addition, two trace elements, Na and Mg, were not completely removed as in other cases but were still retained inside the bone particle. The Ca/P ratio is 1.63 is similar to the Ca/P ratio found in human bones.
, Trần Tuấn Anh, Nguyễn Văn Hạnh, Nguyễn Thị Trúc Linh, Trương Thị Hồng Loan, Hồ Mạnh Dũng, Nguyễn Văn Đông, Đinh Thanh Bình
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.961

Selenium (Se) is a trace element that plays an important role in the biological functions of the human body. Toenails are considered as suitable materials for finding the relationship between trace element content with human diseases. The goal of this study is to analyze and evaluate the Se content in the toenails of colorectal cancer patients in order to find out the risk of cancer in human. The Se content in the toenails of 60 colorectal cancer patients (63.3% for men) and 22 healthy persons (54.5% for men) was analyzed by the k0-standardization method of the instrumental neutron activation analysis technique. The results of the analysis showed that Se contents ib healthy persons were 1.13 mg/g and 1.32 mg/g for men and women, respectively; for colon cancer patients were 0.70 mg/g and 0.84 mg/g for men and women, respectively; for rectal cancer patients 0.86 mg/g and 0.82 mg/g for men and women, respectively. By the statistical analysis, it showed that the Se content was significantly different between the patients and the normal patients (p
, Cuong Van Anh Le
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.923

Ground penetrating radar method (GPR) is common place in imaging buried objects, such as: supply water and drainage systems, electric and telecom cables. For shallow geology, GPR method has provided high-resolution sections containing subsurface information. In processing data, the velocity of GPR wave is the most important parameter. It helps to exactly specify the structure of a geology sections. Defining a wrong velocity may lead to an erroneous result. In this research, we are going to present two processing steps to define the electromagnetic wave velocity and the position of object from GPR data that was acquired by using a shield antenna machine prototype. The first step is application of Kirchhoff migration and energy difference graphs to calculate the electromagnetic wave velocity. In the second step, the result of migrated sections consisting of hyperbole diffraction was evaluated. If migrated using the right velocity, the diffracted hyperbola will focus on its peak and have the maximum energy. Finally, we used the workflow to define the velocity, the position and the size of the object from real GPR data collected at Go Vap district, Ho Chi Minh City, Vietnam.
Hàng Thị Anh Hưng, Lý Đức Phát,
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.935

Deep eutectic solvents (DES), a new generation ionic liquids, are green reactive media in organic synthesis, electrochemical, and biomass conversion. In this paper, we have developed a deep eutectic solvent [ethylene glycol]4[ZnCl2], simply prepared from choline chloride with ethylene glycol and used as a catalyst for the three-component reaction to synthesize propargylamine from available substrates including piperidine, phenylacetylene and benzaldehyde derivatives. The reaction mixture was activated by magnetic stirring and the optimization of conditions was investigated including temperature, time, catalytic mass, substrate effect and recycled catalyst. At 80 ◦ C, we successfully synthesized 5 propargylamine derivatives over a period of 180 minutes with high efficiency and only used 2% moles of catalyst. Desired products are structurally identified by NMR and MS (nuclear magnetic resonance 1H, 13C NMR and gas chromatography coupled mass spectrometry GC-MS). The results showed that DES [ethylene glycol]4[ZnCl2] catalyzed the efficiency of this reaction and the ability to reuse many times with negligible reduction in activity. Research to expand the scope of the substrate (heterocyclic oxygen and nitrogen compounds) and reaction mechanism are underway in the laboratory. Simple, efficient reaction processes have been the potential for industrial applications.
Tra Dong Phuong, Le Thi Mong Vuong, Quach Ngo Diem Phuong
Science and Technology Development Journal - Natural Sciences, Volume 5; doi:10.32508/stdjns.v5i1.917

Perilla frutescens, a plant of the Lamiaceae, is commonly used for traditional medicine to treat diseases (cold, headache, cough, tympanites, poisoning, ...) because it contains many secondary compounds with bioactivities. Roots, stems and leaves of P. frutescens have been extracted with ethanol. These extracts have also been investigated antioxidant by DPPH method and antibacterial by agar-well-diffusion method. The results showed that these extracts possess antioxidant and antibacterial activity. By specific reactions, we found that phenols, flavonoids, saponins, alkaloids and glycosides were contained in all extracts of P. frutescens, but triterpenoids were only found in leaf extract. These secondary compounds are involved in the antioxidant and antibacterial activity of P. frutescens. Next, hairy roots of P. frutescens were induced by Agrobacterium rhizogenes ATCC 15834. The results suggested that leaves were the highest-efficiency (67.67 ± 3.51 % of samples produced hairy roots). 20 minutes of immersion and 72 hours of co-culture are optimal for induction of hairy roots. These results are a pre-requisition for further studies related to hairy root cultures aimed production of bioactive compounds.
Doan Thi Diem Thuy, Tran Duc Dung, Pham Dang Manh Hong Luan, Nguyen Thi Thanh Duyen
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.992

Rural areas and rural livelihoods in many countries have been affected by changes in natural and environmental conditions. In areas where livelihoods relied on the floodwater, changes in flood regimes and the natural environment had significantly impacted many farmers' livelihoods. In the Mekong Delta flooded areas, flood patterns changed mainly due to the hydropower development and the climate change. The livelihoods of many farmers, primarily rice farmers, were facing challenges and needed changes to adapt to the sustainable livelihood development. This study used a sustainable livelihood framework of DFID to assess factors affecting the sustainability in agricultural livelihoods in flooded areas of An Giang province, specifically at Phu Hiep and Phu Long communes of Phu Tan district. We interviewed 60 farmers based on the structured questionnaire and conducted two focus group discussions with more than 40 participating farmers. Our results of the Livelihood Capitals Index (LCI) showed that natural and physical capitals had less impact on household livelihoods. Phu Long is less affected than Phu Hiep by assessing five capitals. Farm households' current livelihoods were mainly affected by the lack of human resources and the unstability of market prices. The rate of consensus on transition to sustainable farming models was not high due to many factors. However, the transition is possible if their production and output are secured by the government.
Nguyen Van Tai, Dao Thanh Son
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.998

The occurrence and impacts of plastic are among the most concerns on the environment, ecosystems, and human health in recent years. Plastic products may contain harmful additives (e.g. phthalate, bisphenol) which can easily be leached out of the surface of the plastic materials and enter the environment causing negative effects on organisms in aquatic ecosystems. However, the toxicity of the leached plastic additives on aquatic organisms including micro-crustaceans have not been fully understood. Therefore, this study aims to evaluate the chronic effects of the leachate from the polyvinyl chloride (PVC) water pipes at the concentration of 0, 10 and 100 mg PVC/L on the survival and reproduction of two micro-crustacean species: Daphnia magna, and Ceriodaphnia cornuta. The results showed that the leachate from PVC pipes at the concentration of 100 mg/L did not adversely affect on survival and reproduction of D. magna, but reduced up to 50% of the survival rate and 60% of the reproduction of C. cornuta. The tropical micro-crustacean species C. cornuta was more vulnerable than the temperate one, D. magna. The results revealed the potential health risks of the PVC water pipes C. cornuta was recommended to be used as a model organism for the toxicological investigation and environmental assessment.
, Nguyen Tuyet Vy, Nguyen Thao Nguyen, To Thi Hien
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.988

Currently, microplastics (MP) in the water environment is a global issue. Microplastics enter the natural environment through various sources such as domestic wastewater and industrial wastewater. The flocculation method - one of the simple and effective methods commonly used in wastewater treatment plants was used in this study to determine the removal efficiency of MPs in the industrial wastewater. The coagulation/flocculation experiments were carried on the Jartest model with the iron coagulant under different conditions. The wastewater was taken from the industrial park Song Than 1. The volume of the wastewater in each experiment was 500 mL with the MPs concentration of 78.4 mg/L which included 3 main forms with MP bead (322 different types / 0.5 L), MP fragment (131 different types / 0.5 L) and MP fiber (125 different types / 0.5 L). The optimal condition of microplastic removal (iron coagulant (FeCl3) = 600 mg/L, pH 8.6 – 8.8, settling time = 60 minutes, fast stirring of 300 rpm, slow stirring of 25 rpm, supporting-coagulant (CPAM) = 50 mg/L) was determined, corresponding with the MPs removal efficiency of 93.11% (MPs in effluent was 7.33 mg/L). The most common MPs categories collected after treatment were MP fragments (19 different types) and MP fibers (17 different types). MPs dimensions were mostly about 0.5 to 1 mm. Our result showed that the coagulation/flocculation process was an efficient method for the removal MPs in the industrial wastewater.
, Nguyen Thi Hung Thanh
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.1000

In recent decades, forest conservation and development have been recognized as the decisive issues at both national and local levels. It is important to evaluate the impact of the local communal activities on the forest and to come up with a conservation and development solution for the forest. Our research developed the Forest Conservation Index (FCI) based on four criteria. Namely forest coverage, harvesting intensity, ratio of natural forest and replanting period after harvesting. The contributing level of each criterion in FCI were examined by consulting forest experts. Based on there, the classification of forest sustainability and the assessment of forest conservation were conducted. FCI was built using the same approach of the US water quality index. The FCI is used to evaluate forest conservation of a specific case, Tam Lanh commune. Tam Lanh was a mountainous commune of Phu Ninh district, Quang Nam province, with over fifty percent of household's livelihoods depending on the forest and its service. The result showed the forest resource of Tam Lanh commune was conserved at an average level. The area covered with forest increased due to econmomical benefit of combining of household benefit and forest resources development. However, the forest quality tended to decrease and the forest ecosystem in the commune was gradually simpler.
Pham Thanh Luu, Nguyen Thi My Le, Trinh Hong Phuong, Tran Thi Hoang Yen, Tran Thanh Thai, Ngo Xuan Quang
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.994

Remote sensing techniques have been widely used to measure the qualitative parameters of waterbodies. Total suspended solid (TSS) is an important water quality parameter and a surrogate for the water clarity. It can be used as the indicator of sediment in the reservoir, which usually consists of silt, fine sand and microorganisms. This study aimed to utilize the remote sensing technology, in particular Landsat 8 Operational Land Imager (Landsat 8 OLI), to determine the amount of TSS concentration as well as the spatial distribution of TSS concentration in the surface water of the Tri An reservoir. The relationship between field TSS data collected in March, 2020 and the reflectance values of the the Landsat 8 Oli images was investigated. Results showed that there was a strong linear relationshiop between TSS concentration and the reflectance of the red and near infrared reflectance bands from the Landsat 8 Oli (r ranged from 0.58–0.93), in which the ratio of the red band produced the best correlation with the TSS (r = 0.93, with a standard error of 0.6–1.39 mg/L). Based on the linear regression equation, the TSS concentration calculated from the red reflectance values was used for mapping the spatial distribution of TSS in the surface water of the Tri An reservoir. Our results confirmed the accuracy and potential of using the single band from Landsat 8 OLI for mapping the spatial distribution of TSS in the Tri An reservoir.
, Phan Kieu Diem, Pham Le Giao Huyen, Tran Huu Duy
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.990

The rapid urbanization increases the impermeable surface that leads to reduce the water permeability into the soil, resulting in reducing the infiltration and increasing the surface runoff. This study aims to extract the impermeable surface using Landsat satellite images and to monitor changes in the impervious surface in the period 2015 –2018 in Can Tho city. This study applied the Objectbased Image Analysis (OBIA) method with the Rule-based Image Analysis algorithm on Landsat 8 fusion data with multispectral images and spatial resolution of 15 m in the period 2015 – 2018 using impermeable surface extraction indicators. Impermeable surface map in 2015 and 2018 with high accuracy assessment (T = 95.5% and K = 0.91, 2015; T = 94% and K = 0.88, in 2018) was established and the fluctuation of the impermeable surface increased from 13,746.6 ha (9.55%) to 19,966.67 ha (13.87%) from 2015 to 2018. The research result indicated the infrastructure development situation and urban construction in Can Tho city during three years increasing of 4.32% of the total natural area in Can Tho city.
Que-Nam Thi Nguyen, Hai Ha Quang, Phuong-Chi Thi Hoang
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.987

The coast of South Central Vietnam from Danang city to Binh Thuan province is about 1200 km long, distributing many geological and geomorphic heritages of high scientific values, including representativeness, integrity and rarity, deserving to build a national geopark such as: i) Ly Son volcanic island geopark is formed up of volcanic materials mainly explosive in the late Holocene age; ii) Phu Yen coastal geopark possessed geological and geomorphic diversity with the presence of ancient Pre-Cambrian rocks; iii) Red Sand Plateau and Rocky Coast Ninh Thuan- Binh Thuan geopark has shaped by intrusive and extrusive igneous rock tips and characterized by majestic red sand plateau. The three geological parks will be established as a legal basis for the conservation of geological and geomorphological heritage for the research, education and local economic development.
, Vuong Hong Nhung, To Thi Hien
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.986

This study was conducted to provide a preliminary assessment on the microbial pollution in the air at some garbage collecting places and waste transferring stations at Ho Chi Minh City. The airborne microbial pollution is becoming more and more important, so the research was carried out to build long-term practical solutions that directly or indirectly protect the environment and ensure the human health. We performed sampling at 3 locations and quantitative analysis - identification for bacteria and fungi that existed in the outdoor air at the collected places of some districts. Samples were collected from 03–06/2019 according to Koch's deposition method. Sampling plate was placed at a height of 1.5 meters above the ground, and the sampling time was 15 minutes. The dish after collecting the sample was placed in the incubator at 37 +/- 1 oC in 24–48 h for bacteria and 25 +/- 1oC in 72–120 h for fungi. The study results showed that the density of bacteria and fungi ranged between 6,408.1–14,599.9 CFU/m3 and 733.6–2.497.6 CFU/m3. In particular, the density of bacteria tended to increase from the morning to the afternoon and decreased slightly in the evening, but the density of fungi tended to increase from the morning to the evening. All strains of microorganisms in the outdoor air were influenced by human activities and environmental factors. Dominant microorganisms were identified including Bacillus pseudomycoides, Bacillus pumilus, Arthrobacter cretinolyticus, Staphylococcus kloossi, Bacillus sp. and the three common fungi including Cunninghamella sp., Aspergillus flavus and Aspergillus brasiliensis. All these microbes are associated with a number of human diseases.
Thai Thanh Tran, Nguyen Thi My Yen, Tran Thi Hoang Yen, Pham Thanh Luu, Ngo Xuan Quang
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.985

Macrofauna communities in Ba Lai estuary, Ben Tre province were investigated in three transects from the river mouth to the dam construction, in the order from the right, middle to the left bank. The community characteristics such as the composition, density, biodiversity, and the distribution pattern were recorded and analyzed. The results showed that the macrofauna communities in the marine section part of Ba Lai river consisted of 76 species belonging to 3 phyla: Mollusca, Arthropoda, and Annelida. In this study, it was notable that a high economic value of Ben Tre Clam (Meretrix lyrata) presented in the Ba Lai estuary with a density of 3160 ind /m2 on the right bank. The highest density was recorded in the mid transect of the river, followed by the right and the left (2907 +/- 4298, 1813 +/- 2056; 1730 +/- 1590 ind /m2, respectively). The biodiversity of macrofauna communities was measured by the species richness, Shannon – Wiener index, and Pielou's evenness. Diversity indices illustrated that the middle bank had the highest biodiversity. However, the statistical analysis results showed that the density and biodiversity indices in these transects were not significantly different. The main reason might be due to Ba Lai dam impact, which has been accreting alluvial, causing these locations gradually being similar in the environmental conditions. The distribution pattern of benthic macrofauna communities in this study should be considered as a typical distribution of benthos in rivers affected by dams. Macrofauna communities which gave rapid responses to environmental changes should be used as a bioindicator.
, Ha Quang Hai, Nguyen Thi Que Nam
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.997

Phu Quy island – Binh Thuan province, is 120 km southeast of Phan Thiet city, where the long – lasting destruction of waves, wind, and rain into oceanic volcanic materials formed four significant geomorphological heritages. These geomorphosites have scientific and additional values (cultural, aesthetic, and ecological values), of which mountain Cao Cat cinder cones deserves to be a South Central Coast geomorphosite; while mountain Cam volcano, Hang Cliff – Nho beach erosion coast and Tranh volcanic islet are proposed at a local level. The impressive cliffs exposed layers of coarse and steeply sloping sediments caused by blasting; erosion coastal terrain such as cliffs, rocky headlands, stacks, arch, islets, etc. all shapes and colors associated with landmarks such as Mong Tay tack, Gam inlet, Ban inlet, Xuong Ca headland, Phat inlet, Dried Squid pond, Den islet, Giua islet, Do islet... are outstanding scientific values. Furthermore, Sa Huynh cultural relics (2,500 – 3,000 years ago) discovered in mountain Cao Cat; Linh Son, and Linh Buu ancient pagodas; Phu Quy landscape viewpoints from mountain Cam Lighthouse or colorful coral reefs on Tranh islet... are additional values that increase the worth of Phu Quy island's geomorphosites. Interpreting the scientific and additional values of these geomorphosite with images, books, geometrically similar models, etc. would promote the geotourism – a niche of the sustainable tourism market that is developed along with Global Geoparks recognized by UNESCO.
Nguyen Thanh Tam, Nguyen Hoai Phuong Duy, Tran Thi Phuong Thuy, Võ Thi Thanh Tien, Tran Cong Khanh
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.1002

In this study, adsorbent materials from natural feldspar were fabricated for application in +NH4 removal. Raw, pretreated by HCl 3M, and modified feldspar by NaOH and aluminum (Al powder, Al(OH)3, and AlCl3.6H2O) were used. Feldspar was modified under different experimental conditions including without calcination and calcinated at 500ºC and 700ºC. The influence of various operating parameters consisting of material size, adsorption time, +NH4 initial concentration and material dosage were investigated. Adsorbent materials < 0.1 mm in size showed the highest adsorption efficiency. Subsequently materials with size of < 0.1 mm were used for the following studies to investigate the affect of other parameters on +NH4 adsorption process. The highest removal efficiency (31.10%) and removal capacity (21.80 mg/g) were obtained by modified feldspar by NaOH and AlCl3.6H2O with calcination at 700ºC at +NH4 initial concentration of 5 ppm. Results from the scanning electron microscope (SEM) showed the differences on surfaces of adsorption materials. Modified feldspar had a clean surface and more tiny pores compared to those of raw and pretreated feldspar resulting in an increased surface area. Consequently +NH4 adsorbent efficiency and removal capacity were increased. By BET (Brunauer, Emmett and Teller) the specific surface areas of adsorbent materials were analyzed and the surface areas of raw, pretreated and modified feldspar were 0.484 m2/g, 0.988 m2/g and 2.024 m2/g, respectively. +NH4 adsorbent mechanisms of all raw, pretreated, and modified feldspar materials were found to follow the Langmuir adsorption isotherm with the correlation coefficient R2 = 0.989 which described the monolayer type of the adsorption.
, Nguyen Dinh Hoang Long, Nguyen Thi Diem Thuy, Le Hoang Anh, Dao Nguyen Khoi
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.999

The objective of this study was to develop a set of sustainable development indicators on environmental aspects and apply them to assess the level of environmental sustainability in Phu Quy district, Binh Thuan province. The set of sustainable development indicators was built based on the screening of indicators from some previous studies, as well as developing new indicators to match the research area. The indicators were then be grouped into topics based on the United Nations' 17 sustainable development goals to 2030. In terms of environment, the set of sustainable development indicators includeed 6 topics (main components), 19 indicators (sub-components), of which 6 new indicators were researched and developed for the island and sea area. The result showed that the level of environmental sustainability of the Phu Quy district was good (0.846). In addition, the results showed that the local environmental aspects attained levels of sustainability. Accordingly, main components including clean water - sanitation (MT1), habitat (MT3), natural disaster prevention (MT4) and ocean conservation - sustainable use (MT5) reached the good level of sustainability and tend to keep stable. While sustainable energy (MT2) and forest protection and development (MT6) are quite sustainable. However, the MT6 component tended to decrease that indicated the forest degradation and the impacts on environmental sustainability in Phu Quy district in the future.
Truong Thanh Canh, Thuy-Trang Thi Nguyen, Anh Hoang Le
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.1001

The research conducted a survey of the water consumption in Ho Chi Minh City through the consumption of products from agriculture, industry and domestic. The research identified green water, blue water and grey water footprints in consuming products. Then personal water footprints were calculated and evaluated. The results showed that the average personal water footprint in district 3 was 1556 m3/year (77.15% for agriculture, 15.59% for industry and 7.26% for domestic), district 10 was 1587 m3/year (77.58% for agriculture, 15.17% for industry and 7.25% domestic), Nha Be district is 1681 m3/year (80.48% for agriculture, 12.97% for industry and 6.55% for domestic) and Binh Chanh district was 1744 m3/year (81.57% for agriculture, 11.88% for industry and 6.55% for domestic). In the individual components of the water footprint, water footprints in consuming agricultural products accounted for the major percentage and determined the personal water footprint. The results showed that the individual water footprints in countryside areas were higher than those in urban areas. Depending on the amount and forms of each individual's consumption, their eating habit and daily activities, and the sexes, the personal water footprints were different. The perception and behavior of individuals' water consumption also significantly influenced the overall personal water footprints.
, Tran Hoang Minh, Phan Thi My Xuyen, Nguyen Thao Nguyen
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.989

Expired and unused medicine can be mistakenly reused. This fact endangers the health, especially the elderly and young children. Currently, Vietnam has no regulations and guidelines on how to collect and dispose expired/unused medicines in households. Consequently, how expired/ unused medicines are disposed remain unknown. This study was conducted to investigate the students practice of disposing medicine. The survey was conducted in March 2020, using the "snowball" method on the social networks to spread the google form questionnaires to 525 students of University of Science. Survey results showed that 73.5% of students were keeping at least one unused over-the-counter drug at home while only 36.5% of students kept prescription drugs. The most common medications keeping unused at home are pain relievers and antipyretics (nonprescription groups) and antibiotics (prescription groups). Regarding the expired drugs, more than 80% of students said that they would throw away, nearly 10% keep at home, and 5% return to the pharmacy. For unwanted medicines, 70% of respondents keep at home, 20% will dispose and 15% will give to others. The most common way of the medicine disposal is to dispose together with the household solid waste. The study recorded that 84% students dispose medicines in household waste bin and 8% (likely living in rural area) burn with household solid waste. Disposing medicines with solid waste mean that the large amount of medicines would end up in the landfill. This raised a risk of groundwater contamination from the leachate in landfills. Nearly 80% of students participating in the survey believe that issuing and disseminating instructions for drug disposal and setting up collection points at hospitals and pharmacies is necessary. The study proposed a method to dispose of expired/unused medicines at
Bang Quoc Ho, Hoang Ngoc Khue Vu, Thoai Tam Nguyen, Thi Thu Thuy Nguyen, Nguyen Thi Dang Khoa, Nguyen Viet Vu, Huynh Ba Hung
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.991

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.
, Ngo Ngoc Hoang Giang
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.993

The paper aims to assess the changes of the streamflow under the impact of irrigation constructions in La Nga river basin using the Long and Short term runoff (LST) model. The LST model was calibrated and validated for the period of 1987–1995 and 1996–1999, respectively, to simulate the natural streamflow for the post–construction phase. Statistical metrics, including R2 coefficients, efficiency coefficients (NSE), percent error (PBIAS) and standard monitoring deviation ratio (RSR) were used to evaluate the model performance. The results showed that, LST model performed well in the flow simulation by the high values of R2 and NSE index greater than 0.80, RSR smaller than 0.50 and PBIAS lower than 7.22%. The comparison between the simulated (natural) and observed flows illustrated that there were changes of the flow regime in the post–construction phase. The average seasonal flow decreases 24.59% and increased 12.06% in the wet and dry season, respectively at Phu Dien station. Meanwhile, at Ta Pao station, the streamflow decreased 8.35% and increased 21.11% in the wet and dry season, respectively. The results of this study could be used in planning, managing and regulating the irrigation works'operation, and water resources management in the La Nga river basin.
, Chau Van Tao
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.666

Recently, a high energy electron beam from accelerators studied on the application for foods and medical devices irradiation, therapy, denature material, discolored semi-precious stones and degradation of environment pollution (Gas, Water, and Sludge Waste). The advantages of electron beam from accelerators are high power density and easy focusing on the target, but electron beam is only useful to irradiate on the surface of the irradiation product because their penetration is short. In order to irradiate high area density products, the X-ray converter is used to generate photon (bremsstrahlung effect). In this article, converting efficiency and direction of X-ray emission is measured by film dosimeter and simulated by MCNP-4c2 code. Measurement and simulation results show that converting efficiency depends on materials of the targets and electron energy, the converting efficiency of Ti – H2O – Pb converter at electron beam energy 5.0 MeV, 7.5 MeV, and 10.0 MeV are 5.57 %, 7.12 %, and 13.54 %. Ti – H2O – Pb converter is made up of 3 layers of Ti wrap material with the function of bearing, heat resistance, circulating cooling water between Ti and Pb layers to cooling, so it is applied for the accelerator.
Quang Đại Tran, Hoang Van Nguyen, Mẫn Văn Trần, Phụng Mỹ Loan Lê
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.911

High voltage cathode LiCoPO4 has been taken great interest for high power Li-ion batteries (LIBs). Though Co enhance the cyclability, capacity of materials, Co concentration should be reduced in electrode materials due to its high cost and toxic. In this work, the solvo-thermal reaction following by pyrolysis in inert Ar was investigated to synthesize the electrode materials LiFexCo1-xPO4 (0.1 <= x <= 0.5) for LIBs. The structure of the materials after calcinated at 600 oC, 700 oC and 800 oC was analyzed by X-ray diffraction (XRD). The results indicated that the olivine structure was obtained for all Fe contents, except for x = 0.5. At the content of 0.1 and 0.5, the intensity of impurity peaks in the samples increased with the pyrolysis temperature. Meanwhile, other samples did not display the obvious change of olivine structure. Electrochemical properties of the materials were evaluated via cyclic voltammetry (CV) and Galvanostatic charging-discharging. CV curves of the samples with Fe content of 0.2x0.4 all displayed high intensity and reversible redox peak of Co3+/Co2+ locating at 4.8 V and another peak of Fe3+/Fe2+ locating at 3.5 V. As the Fe content increased, the former peaks decreased while the latter increased due to the change of active species concentrations. Unfortunately, the specific capacities obtained for Fe-substituted materials were lower than the pristine material (70 mAh/g versus 120 mAh/g) and gradually declined during cycling. The results could be due to the electrolyte decomposition in the first charging. However, the sample with x = 0.1 exhibited the best performance with discharge capacity of 70 mAh/g and 73% capacity retention obtained after 25 cycles, which was better than the sample with x = 0.2 and unsubstituted sample.
, Hai Duc Cam Vo, Nam Tuan Phuong Le
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 888-900; doi:10.32508/stdjns.v4i4.956

Dynamic analysis of various structures subjected to moving vehicles using the Euler-Bernoulli formulation is presented in this paper. The method employs a new numerical approach in which the B-Spline basis functions are suggested for the computational implementation. The Dalambert`s principle is used to set up the moving differential equation system acting on vehicle and beam solving by the Newmark's modified average acceleration. The rotation-free technique has been taken account into the general formulation on Euler Euler-Bernoulli beam theory by using only one vertical deflection unknown and ignoring the rotational variable considering for each control point. The validations of the proposed method considered by a complicated moving vehicle are compared to the precisely analytical results. With the most existing methods of finite element method (FEM) and readily exact solutions, the present technique indicated that it could be an effective method in suitably simulating the interaction of the bridge structures and complicated vehicles. Through the obtained numerical results, this study gives recommendations and proper measures to minimize the impact of vehicle on long span structures and significantly reduce the computational time and cost when analyzing and assess to these practical structures.
Thai Thanh Tran, Nguyen Le Que Lam, Nguyen Thi My Yen, Pham Thanh Luu, Tran Thi Hoang Yen, Nguyen Thi Huynh, Lam Van Tan, Ngo Xuan Quang
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.866

Nematode communities were used as a tool to assess the environmental quality status of sediment of the water bodies in Ben Tre city. Eight locations in the main canals and river in the city were surveyed during the rainy season (September). The study recorded 51 genera belonging to 33 families, 10 orders (Araeolaimida, Chromadorida, Desmodorida, Dorylaimida, Enoplida, Monhysterida, Mononchida, Plectida, Rhabditida, and Triplonchida), 2 classes (Chromadorea and Enoplia). The density of nematode communities at most survey locations is quite high, ranging from 29.88 +/- 38.01 to 1172.08 +/- 659.74 individuals/10 cm2. However, the biodiversity is quite low, species richness index (S) ranged from 5.33 1.15 to 18.33 4.72, and Shannon diversity index (H') from 1.28 +/- 0.12 to 3.19 +/- 0.50 and Pielou's evenness index (J') from 0.47 +/- 0.04 to 0.93 +/- 0.04. The Maturity Index (MI) of nematode communities was applied to assess the environmental quality status of sediment. The results showed that the environmental quality status of sediment recorded disturbances, classified as bad to moderate. The colonizer-persister (c-p) combined with the MI is a potential tool in biological monitoring of environmental quality status. However, to increase the reliability of evaluation conclusions, the combination of MI and biological indicators as well as physical-chemical parameters is necessary.
, Nguyễn Trung Độ, Lưu Kiến Quốc, Hà Thúc Chí Nhân
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 789-799; doi:10.32508/stdjns.v4i4.915

Heavy metals are known to be toxic, even at low content (ppm), for living organisms[1,2]. The presence of heavy metals and other pollutants in water continues to be a major concern and the removal of such contaminants is considered as an important solution for environmental remediation[3,4]. In this paper, we study the ability adsorption of Pb2+ and Cd2+ heavy ionic metal on silica nanomaterials which was extracted and purified from Vietnamese rice husk. The structure of the materials was investigated by X-ray diffraction (XRD) and FT-IR spectroscopy. By Adsorption Atomic Spectroscopy (AAS) analysis, the results have demonstrated the time taken for attaining equilibrium adsorption is about 1.5 hours for both cases, and the adsorption capacity of Pb2+ and Cd2+ on silica are 21 and 24 mg/L, respectively.
, My Ngoc Diem Tran
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 776-788; doi:10.32508/stdjns.v4i4.863

The purpose of research is studying the variation of zooplankton community in Ba Lai river in Ben Tre province. Research was conducted in 2 seasons: rainy season (December, 2017) and dry season (March, 2018). There were 7 sampling points in Ba Lai river, Ben Tre province. Our study recorded 95 taxa zooplankton belong to 56 genera, 39 families, 12 orders, 8 classes and 5 phylums. Generally, Rotifers had highest munbers of species among 2 seasons. Rotifers were dominant in density and species composition at all sampling points in the rainy season. Copepods were dominant in density and species composition in the dry season. There were some marine species present at sampling points during the dry season. In addition, the Bray - Curtis analysis showed that the similarity of the zooplankton communities between rainy season and dry season at sampling points wasnot high. This suggests that there was a shift in the structure of the zooplankton community between rainy season and dry season. These are proof to prove the salinity rising in Ba Lai river in dry season. Although there is an irrigation dam to prevent the infiltration of salt water, but the infiltration of salt water is happening. A solution to preserve fresh water to provide local people in dry season is necessary.
Nhan Trung Nguyen, , An Phu Thi Do, Mai Thanh Thi Nguyen
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.948

Boesenbergia pandurata Roxb. Schlecht. (Zingiberaceae), called ``Ngai bun'' in Viet Nam, is one of the Southeast Asian medicinal plants and its rhizomes are used primarily as a spice. This is a perennial, short-stemmed plant, formed by leaf sheaths and can grow up to 50 cm. The leaves are 7-11 cm wide and 25-50 cm long. Its rhizome surfaces are light brown in color, the inner rhizome is yellow, oval-shaped, and has a very aromatic odor. In folklore, Boesenbergia pandurata rhizomes are used as a spice for food processing. This plant contains pinostrobin as the major constituents. Previously showed that pinostrobin compound is the main ingredient together with a variety of biological activities such as antibacterial, inhibition of free radicals, ... Pinostrobin is necessary composition for the screening, testing, and quality evaluation of the rhizomes of B. pandurata species and others in the Zingiberaceae family. This research had conducted a reference standard of pinostrobin isolated from the rhizomes of B. pandurata had 99.26 % purity, which is reliable in medicinal testing. An HPLC method for pinostrobin determination was conducted and The quantitative HPLC analysis was validated for system suitability, selectivity, linearity ranges, and precision. Application of the process to investigate the preparation of extract shown that reflux extraction with ethanol obtained the highest pinostrobin content with 22.05 % in extracts and 2.89 % in dried rhizomes of B. pandurata.
Ngan Ly Hoang Nguyen, , Nguyen Kim Thi Quyen
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i1.910

The antimicrobial resistance profile of extended-spectrumb -lactamase (ESBL) producing E. coli has been continuously changed in recent years in Vietnam and wordwide. A number of studies recently found that the prevalences of ESBL-producing E. coli decreased in Vietnam from 2016 to 2017 compared with those in previous years. The purpose of this study was to determine the prevalence and antimicrobial profile of ESBL-producing E. coli isolated from clinical specimens in Binh Dan hospital and from healthy individuals at Ho Chi Minh City in 2018. The results showed that the prevalence of ESBL-producing E. coli isolated from healthy individuals in 2018 and 2017 were nearly equal. The prevalence increased from 14.9% in 2017 up to 19.1% in 2018. The prevalence of ESBL-producing E. coli isolated from healthy individuals in Ho Chi Minh City was lower than that in other parts of Viet Nam. The prevalence of ESBL-producing E. coli isolated from clinical pecimens in Binh Dan hospital (22.25%) was lower than those in some other hospitals but higher compared with it from healthy individuals (19.1%). All of the ESBL-producing isolates were multidrug resistant and high resistance to aminoglycoside or quinolone. Imipenem and fosfomycin have still be considered as the treatment of choice against ESBL- producer infections. High resistance rate of E. coli isolated from blood specimens to imipenem was found in the study.
Hoang Van Nguyen, Minh Le Nguyen, Man Van Tran, Nhan Thanh Tran,
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.893

The battery performance not only depend on the electrodes nature but also depend on the choice of electrolyte consisting of salts and organic solvents. The development of electrolytes compatible with both cathode and anode materials is essential for enhancing the performance of practical full-cell Na-ion batteries. Among electrode with difference Ni/Mn/Co ratio, NaNi1/3Mn1/3Co1/3O2 (NMC) showed the best stable cycling. Besides, carbonaceous anode materials such as hard carbon (HC) are attracting due to it low cost, high gravity/volumetric capacity. In this work, the electrochemical performance of full-cell Na-ion including NMC as cathode and HC as anode was studied in difference carbonate-based electrolytes with 2wt%FEC as additive. The cathode material was synthesized by sol-gel reaction following a calcination at 900oC for 12 hours. X-ray diffraction result of the synthesized sample indicates a layered structure with mutual O3 and P2 phase intergrowth and the dominant phase is O3. The impurity phase NiO also presents with negligeable content. In half-cell configuration with sodium metal anode, the material exhibited a typical staircase chargedischarge profile in various electrolytes. The highest capacity of 106 mAh/g with stable clycing up to 50 cycles was obtained in the electrolyte NaClO4 1 M/PC+2wt%FEC. However, this electrolyte couldn't enable the cycling the full-cell HC||NMC due to the incompatibility with HC anode. In consequence, the initial capacity of full-cell in this electrolyte was only 30 mAh/g and significantly decreased in consecutive cycles. Meanwhile, the electrolytes without PC or with low PC content tend to improve the charge/discharge capacity and the cycle life as well. Indeed, full-cell HC||NMC using NaClO4 1M/EC-DMC (1:1) + 2wt%FEC electrolyte exhibited the highest capacity of 90 mAh/g and excellent capacity retention (90% of the initial capacity) after 50 cycles. Additionally, the full-cell could deliver capacity of 55 mAh/g at high rate up to 2C.
Nguyen Ngoc Anh, Nguyen Xuan Hai, Hồ Hữu Thắng, Phan Bao Quoc Hieu, Truong Van Minh
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.860

The present paper proposes an algorithm to improve the energy resolution of two-step cascade spectrum. The energy resolution plays an important role in the domain of gamma spectrum analysis. The better the energy resolution is, the better the ability of peak resolving is. The algorithm is constructed based on an analyze of energy resolution of the summation amplitude of coincident pulses spectrometer using the analogue technique. The algorithm proposed has been tested on some two-step cascade spectra of 164Dy nucleus obtained from the (n, ) reaction experiment using the gamma – gamma coincidence spectrometer at Dalat Nuclear Research Institute. Two-step cascade spectra corresponding to the cascade decays from the compound state to final states whose energies are 0, 74, and 242 keV have been evaluated. The results obtained show that the energy resolution of the two-step cascade spectrum has been reduced by 1.05 to 2.04 times within the energy range of 586 to 6830 keV. Our algorithm can therefore be applied to improve the ability of peak deconvolution, the accuracy, and the realibility in analyzing two-step cascade spectra.
Thao Thi Phuong Dang, Linh My Dao, Anh Man Huynh, Dan Thi Hanh Vo
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 811-817; doi:10.32508/stdjns.v4i4.929

Metabolic syndrome is a collection of disorders related to metabolisms such as obesity, lipid disorders, hyper/hypoglycemia, ... Metabolic syndrome can lead to cardiovascular diseases, strokes, and diabetes - the leading death causes in the world. In many cases, metabolic disorders are original by the redundant/ reduction of insulin- the most important hormone in metabolism regulation. Both of them are involved in beta-cells dysfunction. Many mechanisms related to this phenomenon has been approved, notably mitochondrial dysfunction and the Ubiquitin proteasome system impairment. UCH-L1 is a protein belonging to the Ubiquitin proteasome system and highly expressed in beta cells. Previous studies reported that decrease UCH-L1 function can alter metabolism and lead to b cell apoptosis under various nutritional conditions, however, the mechanism has not been clarified. In this study, we proposed a Drosophila melanogaster model that expresses many symptoms of metabolic syndrome, by knocking down dUCH (Drosophila homolog of UCH-L1) specifically in Insulin-producing cells. Our fruit fly model had abnormal metabolism, physiology, loss of insulinproducing cells, and mitochondria over-workload, similar to metabolic syndrome in humans. These results suggested that this model is suitable for further studies on the role of UCH-L1 in b cells, as well as a potential model in metabolism diseases' drug screening.
, Hong Tong Thi, Phuong Phong Thi Nguyen, Phuc Thanh Hoàng
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 760-766; doi:10.32508/stdjns.v4i4.934

The gold nanostars (AuNS) were prepared through seedless reductive method by using the natural biodegradable polymer chitosan acting both as the stabilizing and shape-directing agent, ascorbic acid as a reducting agent. This reaction synthesis was carried out at room temperature and facile conditions. In an effort to control the size and shape of AuNS, many experimental parameters were investigated for the thorough understanding the role of chitosan in the formation of gold nanostar. In this novel method, the pH condition and appropriate stabilizer concentration were crucial factors to prepare the well-defined AuNS. The obtained AuNS were characterized by many physical-chemistry analysis method such as transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, dynamic light scattering (DLS), and X-Ray diffraction (XRD). The AuNS have an average size of about 55 nm and narrow size distribution when characterized by TEM images. UV-Vis spectroscopy of the gold nanoparticles colloidal solution showed the characteristic peaks at 587-700 nm, corresponding to the surface plasmon resonance of star-shaped nanostructure. The specific interactions between the functional groups of chitosan chain and the as-prepared gold nanostars are analyzed by the FT-IR spectroscopy technique. These results provided insight into the role of biopolymer as both a protecting agent and structure-directing agent. This novel method can overcome previous limitations in controlled synthesis of star-shaped gold nanoparticles such as surfactant use and complex implementation. Besides, the gold nanostars stabilized by chitosan could be a potential material in many applications in the field of biomedical medicine.
Nhan Chi Nguyen, Khang Phuoc Hoang Nguyen, Quan Hoang Nguyen, Hieu Van Nguyen, Huy Thanh Ho
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 800-810; doi:10.32508/stdjns.v4i4.951

This paper presents the design of environmental monitoring and control system in aquaponics based on Internet of Things (IoT) technology. This system allows users to monitor and control the operation of devices through the application on smartphones, including: 3 water pumps, 3 air pumps, pH sensor, dissolved oxygen (DO) sensor, temperature sensor and humidity sensor, exhaust fan and misting. These devices are monitored and controlled in two modes: automatic and manual control. For 3 pumps and 3 air pumps, in automatic mode, allows the user to set the pump time between water pumps and between air pumps. In manual control mode, allows the user to control water pumps and air pumps by the push of a button on a smartphone application. Monitor pH, DO and allows the user to set the pH threshold and DO threshold to give an alert when the pH and DO exceed the threshold. Monitor the parameters of temperature, humidity in the membrane house and allow setting the temperature threshold and humidity threshold to control the exhaust fan and misting respectively when the temperature and humidity exceed the threshold. This system tested at aquaponics farm - Dong Thap Aqua. The results show that this system is working reliably and promising which brings significantly benefits to aquaponics. Besides, it also contributes to improve production efficiency and sustainable development of green agriculture.
Dien Thi Kieu Pham, Kiet Thuong Do, Sanh Du Nguyen
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.891

The cherry tomato fruit size depends on the growth of the pericarp which is parenchymal cells. The blue light stimulates the expansion of cotyledon cells, hypocotyl cells and leaf cells. In this study, the cherry tomato fruit was used as a material to investigate the effects of the blue light on the pericarp cells growth in fruit growth stage and lycopene accumulation in fruit growth and ripening stage. After 7 days of the blue light (440, 450 or 460 nm) treatment, pericarp cells growth and physiological, biochemical changes of the pericarp cells of 7-day-old fruit pericarp piece in vitro were analyzed. The lycopene content and some organic compound contents of 42-day-old postharvest fruits treated by the blue light similarly in 7 days and 7, 21-day-old fruit wrapped with blue filter (440-510 nm filtered) in 7 days were measured. The results showed that the 450 nm wavelength blue light the increased pericarp thickness of 7-day-old fruits through the increasement of the pericarp cell diameter. The 460 nm wavelength blue light the increased lycopene content of 42-day-old postharvest fruits. The blue filter treatment increased the sugar total content of 7- day-old fruits and increased the lycopene content of 21-day-old fruits.
Hoa Van Nguyen, Phi Minh Nguyen, Thien Ngoc Nguyen, Dao Minh Chau, Hanh Thi Thu Tran
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.652

The phonon calculations of hydrogen when adsorbed on the missing row Pt(110)-(1x2) surfaceusing the Ultrahigh Vacuum (UHV) model were studied. The calculations were based on a combinationof Density Functional Theory (DFT) and the approximation of hydrogen vibrations on thesurface. The harmonic vibration of H on the Pt surface was used for the calculation in this study. Atthe hydrogen coverage of 1ML for the model surface (when H completely covering the Pt surface),the interaction formed at the edge of the first layer (short bridge - R) was the most stable. The lessstable positions were recorded as the bridge position between two atoms on a horizontal row inthe second layer (trough - T), the top position of the second surface layer - fcc (F), the bridge positionof the second surface layer - hcp (F'), and the least stable position was the top position of thefirst layer (T'). When accounting the quantum calculation for the model, the adsorption energy ofhydrogen at the short bridge position increased by 90 meV, and the stable adsorption order of hydrogenchanged with the most stable positions ware R, T, T', F', F respectively. This demonstratesdthe significant influence of quantum effects on the adsorption model.
Trang Thị Thu Nguyễn, Ý Thị Đặng, Linh Hồ Thùy Nguyễn, Hạnh Thị Kiều Tạ, Thắng Bách Phan, Tân Lê Hoàng Đoàn
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.927

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.
Bui Anh Thy, Lê Thanh Hòa, Trần Xuân Hạnh, Trần Linh Thước
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 857-867; doi:10.32508/stdjns.v4i4.914

In this study, we compared the genetic mutation and virulence of the attenuated PRRSV strains obtained by 95 serial passages in Marc-145 cells with the parental virulent strain (designated as BG81) isolated in Vietnam. Results showed that there were marked changes in virulence: pigs inoculated with BG81 exhibited high fever ( 41◦C), which lasted for 12 days, and presented typical clinical symptoms of PRRSV; otherwise, pigs inoculated with BG895 (from passage 95), maintained mean rectal temperature from 39,5oC to 39,9oC, did not develop any significant clinical symptoms. Whole genomes of the attenuated strains were significantly different, but their sequence lengths were conserved, i.e., 15,321 nucleotides. The attenuated strain from passage 95 (BG895) contained 38 nucleotide substitutions that resulted in 14 amino acid changes. Most of these changes (about 65%) occurred before passage 50. The 14 amino acid changes were distributed in Nsp1, Nsp4, Nsp9, Nsp10, GP2, E, GP3, GP4, GP5 and N. Specially, there were two single substitutes within a codon in ORF3, corresponding to parallel mutation at position F143L. However, structural protein (M) and eight non-structural proteins (Nsp2, Nsp3, Nsp5, Nsp6, Nsp7, Nsp8, Nsp11 and Nsp12) among the 19 PRRSV proteins, remained conserved, without any mutations and supposed for consideration as irrelative to the attenuation process. It is interesting that in the gene coding for the smallest structural protein (E protein), there was the highest mutation rate among all of the structural genes analyzed, and genetically, seemed to be a highly variable region. These changes may provide the molecular bases for the observation of the attenuated phenotype in pigs. Thus, our variation results obtained between the attenuated BG895 and the parental virulent BG81 strains provide appropriate molecular data for potential use to test and control the masterseed strain in production of a PRRSV vaccine in Vietnam.
Cao Phi Bang
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.960

The ex vitro acclimatization and greenhouse periods play a significant role for the in vitro originated plantlets. In these stages, the micropropagated plantlets have to rapidly adapt to environmental changes. Rhynchostylis gigantea is widely in vitro produced due to highly aesthetic and economic value. The aim of this work was to update the physiological changes of micropropagated R. gigantea plantlets during ex vitro acclimatization and greenhouse stages. The analysis results showed that leaf water content was significantly decreased at day 14 (90.36%) and day 28 (90.17%) stages but increased at day 84 (92.52%) and day 140 (92.34%) stages in compared to in vitro stages, day 0 (92.7%). Dry matter content was changing in the opposite direction to the leaf water content with the highest values at day 14 (9.63%) and day 28 (9.83%), respectively. The leaf transpiration rate was the highest at day zero (0.146 g/dm2/h) in compared to all other studied points. Oppositively, GPX activity was the lowest in plantlets at day zero (13.2 UI/g fresh leaf ) and the highest in planlets at day 14 (36,4 UI/g fresh leaf ). The leaf proline content was higher at day 7 and day 14 stages (132.3 and 150.8 m g/g fresh leaf, respectively) but lower at day 84 and day 140 stages (44.3 and 53.3 microgram/g fresh leaf, respectively) than at day zero (73.7 microgram/g fresh leaf ).
Ho Truong Nam Hai, Nguyen Ly Sy Phu, To Thi Hien
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i4.578

In the current period, with the development of economy, science, and technology, people's lives have been improved, leading to increasing demand for water use. Thus, one of the main current concerns is the increased pollution of surface water and groundwater. Especially water pollution by pesticides is a serious problem. In this study, the wastewater treated system, which is including the aerobic biological process and photocatalytic TiO2, used to evaluate the effective treatment of pesticides. Self-generated wastewater was added by a group mixed 8 types of Organochlorine pesticides (OCPs): Tetrachloro-m-xylene,b -HCH,d - HCH, Heptachlor – epoxide, 4,4'- DDE,b -Endosulfan, Endrin – aldehyde, Endosulfan – sulfate and 5 types of Organophosphate pesticides (OPPs): Diazinon, Malathion, Parathion, Ethion, Trithion. The results showed that the COD removal efficiency was over 89,09% for the whole system when maintaining the load of 0,78 kgCOD/m3. day, total retention time was 16 hours. Five types of OPPs was thoroughly treated after going through the system based on its easily biodegradable. For OCPs, the treatment efficiency through the biological process is not high, 6/8 types about 5 - 27% but through photocatalytic TiO2/UV, the treatment efficiency increased 67 - 100% for each type. The results obtained in the study show that the use of the method of combining biology and AOPs is effective for wastewater difficult to treat as pesticides.
, Ngoc Thi Bao Nguyen, Phung Gia Thinh, Tuyen Thi Kim Huynh, Man Van Tran, Phung My Loan Le
Science and Technology Development Journal - Natural Sciences, Volume 4, pp 767-775; doi:10.32508/stdjns.v4i4.921

Rice husk is a common agricultural waste and an abundant source in Viet Nam. In terms of composition, rice husk is a silica-rich material (SiO2) so it can be used to prepare negative electrode materials for rechargeable Li-ion batteries. Recent processes of synthesizing the silica materials for the rechargeable batteries are often complex, expensive, and energy-intensive. In this study, KOH was used to treat rice husk ash to obtain SiO2/C porous composite materials. X-ray diffraction results (XRD) showed that the diffraction peak between 22o and 23o (2q ) was characterized of SiO2 material, and the other peaks around 43-44o was featured of carbon material. Scanning electron microscope image (SEM) showed the porous structure with the pore size 3-5 mm.Besides, the amorphous structure with coverage layers was also confirmed through the Transmission Electron Microscope (TEM) images. Preliminary electrochemical results demonstratedthat Li-ion coin cell using the SiO2/C anode material exhibited a high capacity of 1200 mAh/g at a discharge current of 1.0 A/g and maintained 1000 mAh/g after 100 cycles. SiO2/C materials prepared from rice husks were highly promising for battery application thanks to their low cost, stable performance, environmental friendliness, and easy expansion for production scale.
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