Vietnam Academy of Science and Technology: Journals Online
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MAXIMIZING LIFETIME OF HETEROGENEOUS WIRELESS TURNABLE CAMERA SENSOR NETWORKS ENSURING STRONG BARRIER COVERAGE
No full textBarrier coverage in wireless camera sensor networks (WCSNs) has drawn the attention of research community since it promises an extremely large potential in applications involve movement detection and surveillance. As the battery resources are limited, improving the efficiency of energy is one of the key drivers for prolonging the lifetime of barrier coverage. However, most prior studies on this problem only worked on the networks with homogeneous sensors as well as omni-directional sensing coverage that have not been taken into account in WCSNs research. This paper thus investigates the problem of maximizing the network lifetime to ensure strong barrier coverage for heterogeneous case (MLBC-HWCSN). We formulate the problem, and then propose a Modify Maximum Flow Algorithm (MMFA) consisting of three stages: constructing the flow-network, finding the maximum flow and refining the solution to solve this problem. Experimental results on extensive instances show that the proposed methodology is suitable for the studied problem and more efficient than existing algorithms.
Whole exome sequencing identified a pathogenic mutation of COL2A1 causing Stickler syndrome in a Vietnamese family
No full textStickler syndrome is a group of rare inherited diseases associated with abnormalities in connective tissues, specifically collagen of the eyes, ears, craniofacies, skeleton and joints. The inheritance pattern of this disease is either an autosomal dominant or an autosomal recessive based on the causative gene. Stickler syndrome is characterized by severe nearsightedness, vitreous abnormalities, distinctive facial features, hearing problems and joint anomalies. Herein, we report a case of a 37-year-old man from Vietnam suspected of Stickler syndrome, presenting a phenotype of retinal detachment and complete loss of vision, and his 3-year-old son with congenital high myopia and vitreous abnormalities. Genetic analysis using whole exome sequencing (WES) revealed a nucleotide substitution (c.C2818T/p.R940X) in exon 42 of the COL2A1 gene that was previously reported as a pathogenic variant causing Stickler syndrome. Validation of COL2A1 c.C2818T in all members of this family by using Sanger sequencing detected the presence of this pathogenic variant in the heterozygous form in the affected father and son but not in the mother and another son without any signs of a vision problem. Thus, our study contributes to not only the knowledge base of clinical and genetic aspects of Stickler syndrome in Vietnam but also the awareness of the importance of genetic counseling in patients with COL2A1 c.C2818T mutation, as well as early diagnosis and appropriate treatment to prevent serious complications, especially blindness
Molecular evolutionary relationships of Vietnamese and global pulmonary Paragonimus species in the family Paragonimidae and suborder Xiphidiata (Platyhelminthes: Trematoda)
No full textParagonimiasis, caused by Paragonimus species belonging to the family Paragonimidae of the suborder Xiphidiata (Platyhelminthes: Trematoda), often occurs in poor, upland, ethnic minorities, in Vietnam and the world. Asian Paragonimus species are distributed from Japan, South Korea, along with North and Southeast China, North-West and Central Vietnam, the Philippines, Thailand, Bangladesh, India, and Sri Lanka. There are various genetic variants, strains, and genotypes forming different complexes and evolutionary lineages. The 18S, 28S rDNA sequences and the intergenic transcribed spacer regions (ITS-1, ITS-2) of nuclear ribosomal transcription units are commonly used as molecular markers in genetic studies and phylogenetic analyses. We obtained a portion of 28S rDNA (domains D1–D3) of Paragonimus spp. including P. heterotremus (from Vietnam), P. ohirai (Japan), P. iloktsuenensis (Japan), and P. westermani (India and Vietnam) and conducted phylogenetic analysis for molecular evolutionary studies. The results showed that the family Paragonimidae formed the biggest cluster in a phylogenetic tree, which comprises of 46 sequences of 11 species belonging to 11 subgroups, among which the P. westermani complex of strains originating from China, Korea, Japan, India, Philippines, Malaysia, and Vietnam is present. P. westermani complex is arranged in a position of "sister" (sister group) with the subgroup P. siamensis. The P. heterotremus and P. ohirai complexes, and the P. miyazakii, P. harinasutai, P. mexicanus, P. kellicotti, and P. macrorchis complexes are clustered in a common population. P. westermani of Vietnam is in close proximity to the East Asian strains, as of which has been previously reported. P. ohirai and P. iloktsuenensis are considered “sibling” species, sharing the same clade. Phylogenetic analysis using the 28S rDNA sequences directly presented species position and their molecular evolutionary relationships in the families Paragonimidae, Troglotrematidae, Nanophyetidae, and Collyriclidae. Evolutionary analysis has also clarified a number of complex delineation problems and made a clear nomenclature for Paragonimus sp. of Vietnam, in particular, which has scientific grounds merited to recognize as that it is really the P. westermani species
DIRECT NUMERICAL SIMULATION STUDY OF WATER DROPLETS FREEZING ON A HORIZONTAL PLATE
No full textWe present the numerical results of the solidification process of water droplets on a cold plate with different wetting angles. The numerical method used is an axisymmetric front-tracking technique. The water droplets are assumed as a spherical cap and placed on the cold plate which is kept at a subfreezing temperature. At the end of solidification, we obtain a small protrusion shape at the top of the frozen water droplet and its height is also higher than that of the initial water droplet. The frozen water droplets are also compared with the corresponding experimental ones reported in the literature
STUDY ON ANTIOXIDANT ACTIVITY OF PHYTOESTROGEN EXTRACTS FROM SOY GERM
No full textSoy germ is one of the richest phytoestrogen sources and thus has many benefits for health such as improving bone density, cardiovascular health, cancer prevention, and menopausal treatment. In addition, phytoestrogens are reported to act as antioxidants, removing reactive oxygen species and thereby preventing oxidative damage in living tissue. Phytoestrogens in soy germ include isoflavone compounds and their derivatives: daidzein, genistein, glycitein, daidzin, genistin, glycitin, acetyl daidzin, acetyl genistin, acetyl glycitin, malonyl daidzin, malonyl genistin, malonyl glycitin. Isoflavones aglycone forms comprise only about 2-5% of total isoflavones, however, they express more biological effects than the others. The objective of this study was to compare the antioxidant activity among three extracts: purified isoflavone aglycone extract, crude isoflavone aglycone extract and total phytoestrogen extract. The IC50 value of DPPH free radical scavenging capacity of purified isoflavone aglycone extract, crude isoflavone aglycone extract and total phytoestrogen extract were 0.763 ± 0.016; 3.345 ± 0.076; 6.142 ± 0.050 mg/ml, respectively. The IC50 value of reducing power activity of purified isoflavone aglycone extract, crude isoflavone aglycone extract and total phytoestrogen extract were 1.248 ± 0.024; 3.961 ± 0.172; 9.385 ± 0.272 (mg/ml). As our result, the ranking order of the antioxidant activity (from highest to lowest level) was purified isoflavone aglycone extract crude isoflavone aglycone extract total phytoestrogens extract
CHEMICAL COMPOSITION OF THE ESSENTIAL OIL FROM LEAVES OF CALLICARPA ARBOREA ROXB. GROWING IN VIETNAM
No full textThe essential oil from the leaves of Callicarpa arborea Roxb. growing wild in Vietnam, was obtained by hydrodistillation and analyzed by gas chromatography – mass spectrometry. The major constituents of leaves of C. arborea were β-selinene (23.9%), ar-turmerone (17.5%) and α-copaene (8.9%), with lesser concentrations of caryophyllene oxide (4.9%) and ar-turmerol (3.9%). The chemical composition of this essential oil sample is being reported for the first time
Effects of in vitro plant ages on the subsequent growth of Plumbago indica l. after ex vitro transplantation
No full textThe Indian leadwort (Plumbago indica L.) of the family Plumbaginaceae is a plant with high pharmaceutical value, as it contains plumbagin, a naphthoquinone with antibacterial, antifungal and anticancer properties. Among the propagation methods for the Indian leadwort, in vitro propagation is considered an effective method in producing disease-free transplants in a short period of time with high propagation rate. When plants grown in vitro are transferred to ex vitro condition, the environmental factors in the nursery house such as light, temperature, humidity and microorganism in the soil will affect their growth. Characteristics of transplants themselves is also critical for the subsequent growth. It is, thus, essential to establish the standards to evaluate and qualify in vitro plants for transplanting to ex vitro condition. Among these standards, the culture age of in vitro plants affects the maturations of their root, stem and leaves, which can in turn influence the acclimating ability and growth of in vitro plants after transplantation. The purpose of this study is to investigate the effects of the culture age of in vitro Indian leadwort plants on their performance during ex vitro stage. For this purpose, three different culture ages of uniform in vitro plants, 35, 42 and 49 day-old, were studied. After 28 days of cultivation in the nursery house under the light intensity of 70 ± 10 µmol m-2 s-1, temperature of 35 ± 4 oC and relative humidity (RH) of 60 ± 10%, all three treatments achieved 100% survival rate. Increased fresh and dry weights and percentage of dry matter after cultivation in ex vitro condition were not statistically different between 42 day-old and 49 day-old in vitro plants, but were significantly different between these plants and 35 day-old in vitro plants. The development of shoot and root in ex vitro stage of 42 day-old and 49 day-old in vitro plants was more balanced, as shown by the higher ratio of shoot/root dry weight, than 35 day-old in vitro plants. The results of this study showed that for this Plumbago species, bigger in vitro plants led to better growth during ex vitro stage. These results also indicated that it was possible to transfer in vitro Plumbago plants to ex vitro condition after 5 weeks of in vitro culture stage.
EXTRACTION OF TRITERPENOIDS FROM THE VIETNAMESE RED GANODERMA LUCIDUM BY ULTRASOUND-ASSISTED EXTRACTION METHOD AND ANTI-OXIDANT ACTIVITY OF EXTRACT
No full textAn ecofriendly ultrasound – assisted extraction (UAE) method was developed for the triterpenoids extraction from Vietnamese red Ganoderma lucidum (G. lucidum). The appropriate kind of solvent for extraction procedure was selected as ethanol based on the yield of triterpenoids obtained, followed by the investigation of four single factors including solvent-to-material ratio, extraction temperature, extraction time, and ultrasonic power. According to the result of single factor experiments, optimal extraction conditions were determined with solvent-to-material ratio of 30:1 mL/g, extraction temperature of 55 , extraction time of 60 min, and ultrasonic power of 480 W. Under these conditions, UAE produced a highest triterpenoids yield of 9.7976 0.334 mg/g by using ultraviolet-visible spectroscopy (UV-Vis) analysis. Extract obtained from UAE method showed better antioxidant activity compared to that of ascorbic acid with the half-maximal inhibitory concentration values were of 32.685 and 6.902 µg/mL, respectively. As a result, triterpenoids extracted from G. lucidum could be considered as a promising antioxidant agent
CHLOROGENIC ACIDS FROM GREEN COFFEE BEANS COLLECTED IN TAY NGUYEN PROVINES OF VIETNAM
No full textSix chlorogenic acid compounds, including 5-O-Caffeoyquinic acid (1), 3-O-Caffeoyquinic acid (2), 4-O-Caffeoyquinic acid (3), 3,5-O-Dicaffeoylquinic acid (4), 3,4-O-Dicaffeoylquinic acid (5) and 4,5-O-Dicaffeoylquinic acid (6) were isolated from the methanol extract of green coffee beans collected in Gia Lai, Kon tum, Tay Nguyen provinces of Vietnam. Their structures were determined by ESI-MS, 1D and 2D NMR spectra and by comparison with the reported spectral data. This is the first report on the isolation of chlorogenic acid compounds from green coffee beans of Vietnam. 3-O-Caffeoyquinic acid was isolated as the main component with extraction efficiency of 0.58 % compared to dried material weight
Zooplankton community in Thi Nai lagoon in the period of 2001–2020
No full textThis paper presents the results of the surveys on zooplankton in Thi Nai lagoon from 2001 to 2020. There were 179 species found in the lagoon, among which Copepod was the dominant group with 97 species (50.78% of total species), followed by Cladocera with 20 species (10.36%), Hydrozoa with 18 species (9.33%), Tunicata with 11 species (5.7%) and Siphonophora with 10 species (5.18%). Based on Bray-Curtis similarity analysis of zooplankton community and the station position, the sampling stations in the lagoon were grouped into three areas: The upper lagoon (UP), the middle (MI), and the mouth of the lagoon (MO). Among the surveyed years, there was a slight variation in the species number, while the density decreased by time and was especially low in 2020. Zooplankton density was much lower in the rainy season compared to that in the dry season, while the species number was less varied. Analysis of the differences between the areas in the lagoon demonstrated a clear distribution pattern of zooplankton with a decreasing density and an increasing number of species from upper lagoon to the mouth of the lagoon. Zooplankton diversity was less affected by time and only the Pielou index in the MI area between 2004 and 2009 was significantly different. Analysis of the various indices between seasons showed that the MO area was less volatile than the two other regions. The multi-dimensional scaling analysis demonstrated that zooplankton community was less variable by regions (50% similarity) compared to by the years (only 30% of similarity), except in 2009 and 2020 when differences among the areas were significant. Seasonal community change between the dry and rainy seasons was 30%