Science and Technology Development Journal - Natural Sciences

Journal Information
ISSN / EISSN : 2588106X / 2588106X
Current Publisher: Viet Nam National University Ho Chi Minh City (10.32508)
Former Publisher: Biomedical Research and Therapy (10.15419)
Total articles ≅ 317
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Trân Huỳnh Ngọc Dương, Diễm Thị Lê, Mai Thị Bạch Võ
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.710

Abstract:
Abelmoschus sagittifolius Kurz is a medicinal plant with typical pharmacological of ginseng. However, the number of trees in the nature wild is declining rapidly due to the increasing demand for logging along with the narrowing of the distribution area and the low incidence of seed germination, affecting the use for researching and developing gene sources for drug production in many areas. In this plant, root is the most important organ of the plant, so the study of root formation in in vitro has been of great significance in assessing the effect of plant growth regulators on induction roots, as well as creating a source of starting material for studies on the biosynthesis of saponin in in vitro compounds as an alternative to outside planting. The results showed that after 2 weeks of culture, the germination rate was highest (88%) when the seeds were disinfected with HgCl2 0.1%, 3 minutes and then soaked in GA3 20,0 mg/L, 120 minutes, finally seed culture on MS + 20 g/L saccharose + GA3 5.0 mg/L + 7 g/L agar. The callus formation from hypocotyl in the environment on MS medium + 20 g/L sucrose + NAA 0.5 mg/L + BA 1.5 mg/L + 7 g/L agar was appropriate for root reduction and the best root formation was applied in the medium of MS + 20 g/L sucrose + IAA 0.3 mg/L + 7 g/L agar. In conclusion, the method of tissue culture is suitable for the formation of adventitious roots from callus formation from hypocotyl of Abelmoschus sagittifolius Kurz.
Dao Thi Hong Pham, Trang My Ho Nguyen, Vy Thuy Nguyen
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.898

Abstract:
Infection with Helicobacter pylori (H. pylori) is the strongest known risk factor for gastric cancer. The molecular mechanisms of H. pylori-associated gastric carcinogenesis remain not elucidated. Recent findings indicate that H. pylori infection may promote gastric carcinogenesis by inducing inflammation and genetic instability in gastric epithelial cells. In addition, it is shown that the impact of H. pylori on infected cells is associated with bacterial virulence that is diverse among geographical regions as well as populations. Therefore, we aimed to investigate the effect of H. pylori strain DN18 from Vietnamese subject on the in vitro activity of NF-κB transcription factor, a key regulator of inflammation, and expression of its target genes in this study. Moreover, host genomic instabilities were studied through examining the formation of DNA double-strand break (DSB) by using phosphorylated histone H2AX (γH2AX) as a DSB marker. Our results showed that H. pylori strain DN18 induced activation of NF-kB pathway and increased transcriptional expression of inflammatory mediators in human gastric mucosal cell AGS. We also provided evidence that the H. pylori infection triggered accumulation of DSBs marker γH2AX. In summary, our study showed the potential ability to cause inflammation and DNA damage to infected cells of H. pylori strains isolated from Vietnamese patients.
Tran Van Xuan, Nguyen Dinh Chuc, Nguyen Tuan, Truong Quoc Thanh, Pham Viet Au
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.894

Abstract:
According to petrophysical and geophysical data, the depositional facies of E Oligocene are determined. Furthermore, the correlation lines between wells and the seismic line also created for confirming Oligocene E distribution in Cuu Long basin. Using appropriate methods such as petrophysical curves, geophysical characteristics, interpretation of gross depositional environment as well as mapping of seismic attributes for sub-sequence Oligocene E upper and E lower in Southeast area, results of prediction the sand distribution in Oligocene E upper and E lower sub-sequence, factors effect to porosity-permeability preservation of E sand reservoirs in Southeast area, Cuu Long basin and oil-gas industry flow-producing possibility in varied sedimentary facies were reported in this paper. The E Oligocene sedimentary distributes in a large area with hydrocarbon accumulations along the Southeast margin Cuu Long basin in relation with the existence of half-grabens along Con Son swell, in which formation rocks consist of varying grain size, mainly sandstone interbeds by siltstone and shale stone. A bitum shale layer of 20÷70 m thickness exits to play the role of a shield to maintain a much higher effective porosity of the reservoir section than usual (up to 18%). In the area, there are two sandstone reservoirs of excellent quality at 2,600÷2,700 mMD and 3,000÷3,400 mMD depths. In order to determine the oil and gas potential of the target, petroleum systems in exploration activities must carefully be evaluated, especially looking for stratigraphic traps, and the reservoir modeling should be modified accurately.
Nhat Vu Pham, Nguyen Thanh Si, Mai Mac Son, Pham Thi Bich Thao, Nguyen Van Hong, Pham Tran Nguyen Nguyen
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.871

Abstract:
Density functional theory (DFT) is employed to examine the adsorption mechanism of DNA bases (adenine, guanine, cytosine, and thymine) on the gold surface using Au6 cluster as model reactant. Geometries of resulting complexes are optimized using the PBE functional in conjunction with the cc-pVTZ-PP consistent-correlation pseudopotential basis set for gold and the cc-pVTZ basis set for the non-metals. The binding sites and energies, along with several quantum chemical indicators are also investigated at the same level of theory. The binding energies between Au6 cluster and DNA bases are computed to be around 14–25 kcal/mol in gas-phase and slightly reduced to 10 – 20 kcal/mol in the water environment. Cytosine has the highest affinity with gold cluster, decreasing as follows cytosine > adenine guanine > thymine. If a visible light with a frequency of Hz (500 nm) is applied, the time for the recovery of Au6 from the complexes will be in the range of (for thymine) to 10 (for cytosine) seconds at 298 K in water. In addition, the geometric structures of both the gold cluster and DNA bases are almost unchanged during the complexation. The gold cluster is found to benefit from a larger change of energy gap that could be converted to an electrical signal for the detection of these molecules. Current results could provide us with fundamentals for understanding the DNA bases absorption on gold nanoparticle surfaces at the atomic and molecular levels.
Nguyen Minh Ky, Nguyen Cong Manh, Phan Van Minh, Nguyen Tri Quang Hung, Phan Thai Son, Nguyen Anh Duc
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.702

Abstract:
The paper presented results of the comparative assessment of nutrient absorption capacity by plants, including reed grass (Phragmites australis L.) and vetiver (Vetiveria zizanioides L.). The constructed wetland models were designed with experiments (i) - Loading 1 (T1): reed grass (S1), vetiver (V1) + control (C1); (ii) - Loading 2 (T2): reed grass (S2), vetiver (V2) + control (C2); (iii) - Load 3 (T3): reed grass (S3), vetiver (V3) + control (C3). The study investigated the surface water quality parameters including nutrients such as TKN (Total Kieldalh Nitrogen), ammonium (NH4-N), nitrite (NO2-N), nitrate (NO3-N), total phosphorus (TP) and phosphate (PO43-). Results showed that there was significantly decreasing change related to pollutant concentration in the tanks. The studied results showed that the water treatment efficiency of Loading 1 (T1) possessed highly nutrient absorption capacities such as nitrogen and phosphorus. Comparing the nitrogen and phosphorus removal efficiency, there was no statistically significant difference between reed grass and vetiver in the same loading (P>0.05). In general, in the same loading levels, the plants’ nutrient removal efficiencies were often higher than the control experiments (P
Mỹ Trâm Thị Phạm, Thuỷ Tiên Thị Lê, Sương Kế Ngô
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.763

Abstract:
Xa den (Ehretia asperula Zoll. et Mor.) belongs to the Boraginaceae family, which is a precious medicine, called “cancer” tree in Muong at Hoa Binh province traditional medicine. Xa den was shown to inhibit the development of malignant tumors, reduce oxidation, enhance resistance... In this study, we investigated the induction of friable callus in Xa den young stem section that could be further used to the culture cell suspension and produce bioactive compounds. In that, we focussed on the effects of the plant growth regulators, mineral media, and pH on the formation of friable callus of Xa den. The results showed that all treatments stimulated the formation of callus from Xa den thin stem (0.5-1.0 mm). In particular, samples which were cultured in B5 medium supplemented with 0.4 mg/L 2,4-D and 0.1 mg/L BA, at pH 5.8 produced the highest percentage of secondary callus in friable (85%), and this callus also had highest fresh weight after 4 weeks of culture (0.054 g). To evaluate the presence of natural compounds in the callus and compared to those in cultivated plants, the ethanol extract of dry leaves, branches, and fresh callus were used. The results showed the presence of natural compounds in the callus such as organic acid, phenolic, tannin, alkaloid, and flavonoid was similar to the one in a 2-year-old plant.
Thanh Ngoc Do, Duyen Thi Pham, Phuong Kim Lieu
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.856

Abstract:
Petrographical characteristics and post-depositional alteration studies of sandstones are the two important factors to reservoir rocks, which affect oil and gas storage and permeability of reservoir rocks. This study revealed petrographical characteristics, post-depositional alteration, and their influence on the porosity and permeability of Oligocene sandstones, including C, D, and E and F sequences, block 15-1/05, Cuu Long Basin. The results show that most of the sandstones were arkose, lithic arkose, and sporadically interbedded by feldspathic greywacke. The post-depositional alteration was progressively increasing following the burial depth from early diagenesis of sequence C, to intermediate diagenesis of sequence D and advanced diagenesis of sequence E and F. The post-depositional alterations significantly influenced on the porosity of the Oligocene sandstone were the cementation and mechanical compaction. They reduced the porosity and permeability of the sandstone. Additionally, authigenic clay minerals have a negative effect on permeability in which sandstones were rich illite and illite-smectite clay minerals, and the permeability tended to decrease stronger than others. Our results showed that the potential reservoir rocks of Oligocene sandstones, block 15-1/05 were sequence E and F sandstones that are in well grain sorting, well grain roundness shape, and contained a small number of cement, particularly the absence of illite and illite-smectite.
Mạnh Khắc Nguyễn, Hòa Từ Nguyễn, Khuê Ngọc Nguyễn, Diễm My Lâm Huỳnh, Du Huy Nguyễn, Mai Ánh Nguyễn
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.874

Abstract:
The present research describes a simple and inexpensive derivatization method that uses acetylation to address the challenges associated with the quantification of the ten most common carbohydrates. The derivatization reaction has two periods : (1) The oxime formation of carbohydrates was carried out at 15 minutes, 500 µL of NH2OH 2.5% and 60 ºC and (2) acetylation of carbohydrates was carried out at 45 minutes, 600 µL of AAA and 80ºC. Most of the carbohydrates generate single peaks via chromatographic separation, except fructose, which generates a double peak. The procedure was successfully applied to analyze carbohydrates in some samples including honey, fresh milk, and polysaccharide hydrolyzate. The method validation results had the linear concentration range of carbohydrates at 50-4000 mg/g, the LODs at 20-50 µg/g, the relative standard deviations (% RSDs) of peak area under 5.0 % and the accuracy at 95–115% of recoveries. The method was applied to determine carbohydrate content in raw milk, honey, and hydrolysis polysaccharide extract. The results showed that the honey sample has fructose and glucose content of 65.8% and 33.4%, respectively, while sucrose makes up 0.74% of the total carbohydrate content. The raw milk sample has lactose content of 47.6% of the total carbohydrates. Some rare polysaccharides such as arabinose and xylose were found in the hydrolysis polysaccharide extract from the mushroom sample.
Doan Phan Phuong Thao, Tuan Anh Le, Phan Ngo Hoang
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.833

Abstract:
Polygonum cuspidatum Sieb. et Zucc, a medicinal plant, contains many phenolic compounds such as resveratrol. It has antioxidant, antibacterial, anti-cancer, HIV, and neuron protective properties. In this study, stem segments having an auxiliary bud were cultured in vitro on MS medium supplemented with TDZ at 0.1 mg/L for obtaining the highest number of shoots (8–9 shoots/cluster after eight weeks). The bud shoots were originated from the differentiation in the periphery of the lateral meristem. After eight weeks, the shoots cultured under the monochromatic light showed that the plant height, fresh and dry weight was higher than those grown under the fluorescent light at the same intensity of 50 µmol photon/m2/sec. Blue LED reduced the number of shoots/cluster, and respiration intensity of the inoculum compared to the red LED or fluorescent light conditions. However, after eight weeks, the total sugar and phenolic content in leaves and stems, as well as the resveratrol content of shoots under blue light, were always higher than under red LED or fluorescent light. Moreover, when samples were exposed under the one-week blue light condition at a double intensity (100 µmol photon/m2/sec), the shoot clusters growing under blue LED also had a remarkably high total phenolic content and significantly high resveratrol levels compared to the two other treatments. The roles of endogenous growth regulators in shoot clusters under different lighting conditions were also analyzed and discussed.
An Nang Vu, Nhi Van Nguyen, Van Thi Thanh Tran, Nhan Chi Ha Thuc, Hieu Van Le
Science and Technology Development Journal - Natural Sciences, Volume 4; doi:10.32508/stdjns.v4i2.658

Abstract:
Cellulose nanocrystals (CNCs) is one of the interesting materials attracting many researchers from the decades, especially when they are extracted from natural biomass resources. The aim of this study was to explore the utilization of rice husk residues as source for the production of CNCs. Cellulose was extracted from rice husk based on chemical method, using the formic/ peroxyformic acid process in order to effectively remove lignin and hemicelluloses from raw material. The cellulose was then treated by acid hydrolysis process performing at 45oC for 30 min, using 15 mL of H2SO4 (64% wt) for each gram of cellulose. The material obtained after each stage of the treatments was carefully characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission electron microscopy (TEM). Morphological characterization from TEM revealed the appearance of needle-like shaped CNCs, average diameter and length of 15 nm and 480 nm, respectively. FT-IR results indicated that lignin was completely removed from the samples during chemical treatment. The thermal stability of the materials in successive treatments was also investigated using thermogravimetric analysis (TGA). These promising results proved revalue of this by-product for the production of CNCs and its potential use as reinforcement in the preparation of nanocomposites.
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