bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceptions of multimodal learner-driven feedback in EAP
Authors: Maas Clare
Published: April 2018

The ‘Learner-Driven Feedback’ (LDF) procedure is innovative in its combination of approaches to feedback provision in second/foreign language writing instruction which a) respond to learners’ individual queries and b) employ digital modes of delivery ([anonymised ] 2016). In LDF, formative feedback is given by the teacher, but the learners indicate on what aspects of their writing and in what mode they would like to receive feedback. In this study, LDF was used with 36 postgraduate students of an English for Academic Purposes (EAP) class at a university in Germany. The presented analysis of survey data highlights high levels of receptivity to LDF and reveals students’ perceptions of the affordances of different digital delivery modes for improving their writing. While feedback in the form of margin comment bubbles was perceived to be helpful to foster improvement in general language accuracy, students preferred emailed or audio-recorded feedback for the improvement of their writing related academic skills. The potential applicability of LDF for EAP and other writing instruction contexts is discussed based on these findings.
PURIFICATION OF RAVE COMPLEX FROM Saccharomyces cerevisiae USING FLAG TAG-AFFINITY PURIFICATION METHOD
Authors: Thanh Trung Nguyen , Thi Tam Pham , Thi Thu Thuy Ta , Gu Chunyin , Zhang Zhenyu
Published: April 2018

RAVE (Regulator of the H+-ATPase of the Vacuolar and Endosomal membranes) is an            essential factor of assembly and reversible disassembly of V-ATPase. RAVE complex has three subunits, which are Rav1p, Rav2p and Skp1p. There are few studies on RAVE so it is very             important to study structure of RAVE complex to understand more about the regulation of the assembly and reassembly at V-ATPase. In this study the RAVE complex was purified by affinity purification by fussing FLAG tag to subunit Rav1p or Rav2p. Experimental process: yeast cells were incubated in 8 L YEPD medium at 30 oC, 200 rpm (OD600nm around of 3). Furthermore                   harvested cells were broken by a French pressure cell disruptor at 25,000 p.s.i in TBSE (50 mM Tris/Cl, 150 mM NaCl, 1 mM EDTA, pH 7.4) with 1 mm PMSF. The cell lysate was centrifuged at 20,000 xg for 20 minutes at 4 oC. Then, the supernatant, was achieved by centrifugation, and loaded onto a small column contained 1 ml of anti-FLAG M2 gel. After washing anti-FLAG column with TBSE, RAVE complex was eluted with TBSE containing 100 µg/ml FLAG               peptides. The results showed RAVE complex purification from strain with FLAG tag fused in                 C-terminus of Rav2 is better than RAVE complex purification from the yeast strain S. cerevisiae with FLAG tag fused in N-terminus of Rav1 or C-terminus of Rav1.
FATTY ACID COMPOSTION OF SELECTED VIETNAMESE BISCUITES INCLUDING TRANS-ISOMERS
Authors: Quoc Tuan Hoàng , Hong Son Vu , Thi Minh Tu Nguyen
Published: April 2018

In this study, fatty acid compositions including trans-isomers contents of selected Biscuits products produced by Vietnamese confectionery companies and imported products purchased from Hanoi markets were determined by gas chromatography. Palmitic acid and oleic acid were the most abundant, with concentrations ranged from 21 % to 52 %, and 23 % to 43 %, respectively, and followed by linoleic acid, lauric acid, myristic acid. The saturated, cis-monounsaturated and cis-polyunsaturated fatty acid contents were within ranges of 37 % - 75 %, 18 % - 43 %, 0.4 – 26 % of total fatty acid methyl ester, respectively. Trans-fatty acids were identified in all samples excepted brands B3, B13, B17, B24*, and the contents ranged from                    0.07 % to 7,16 %.  A considerable variability in fatty acid composition of biscuits which indicated that different types of fats and oils were used for production of selected Vietnamese biscuits and imported products was showed by these results got from the study.
ADAPTIVE TRACKING CONTROL FOR TWIN ROTOR MULTIPLE-INPUT MULTIPLE-OUTPUT BASED ON ISS STABILIZATION
Authors: Chi Nguyen Van
Published: April 2018

This paper proposes the angle tracking control method for Twin rotor multi-input multiple-output (TRMS) using the input-to-state stability theory (ISS) for nonlinear systems. To apply this theory, the model of TRMS is rewritten by an Euler-Lagrange forced model with uncertain parameters and input disturbances. The uncertain parameters are the potential energies depended on the mass of TRMS’parts and the input disturbances are considered the friction force, the flat cable force, the effects of the speed of the main rotor on the horizontal movement and the speed of tail rotor to the vertical movements. Using modificated model of TRMS, we design the adaptive controller for angle ISS stabilization to attenuate the influences of uncertain parameters and input disturbances to the angles of TRMS. The robustness of the closed system is shown by the the stabilization of the angles with the yaw and pitch external disturbances, the simulation and experimental results help to proof the rightness of proposed method.
River hydrology and recent suspended sediment flux in the Red River: implication for assessing soil erosion and sediment transport/deposition processes
Authors: Thi Ha Dang , Coynel Alexandra
Published: April 2018

Based on a database of daily water discharge and daily suspended particulate matter concentrations along the Red River and at the outlet of the main tributaries (Da and Lo) during the 2005-2010 period, covering contrasting hydrological conditions, the water and sediment fluxes transported by the Red River system were determined. The results showed that only 21% of the discharge is derived from the upper Red River, 54% and 25% being derived from the Da and the Lo Rivers, respectively. In contrast, the distribution of suspended particulate matter (SPM) load is very different of that observed for water discharge: most SPM were eroded from the upstream catchment located in China (78%). Moreover, annual SPM fluxes (FSPM) showed a strong spatial variability between upstream watershed and the outlet of the river. The mean inter-annual FSPM was 30 Mt/yr (i.e. specific flux of 741 t/km²/yr) at the LaoCai site, 38 Mt/yr (i.e. 792 t/km²/yr) at the PhuTho gauging site, 29 Mt/yr (i.e. 193 t/km²/yr) at the SonTay gaugng station. Its values were 4.1 Mt/yr (i.e. 80 t/km²/yr) and 6.6 Mt/yr (i.e. 191 t/km²/yr) for the Da and Lo rivers, respectively. Between the LaoCai and PhuTho sites, both erosion and sedimentation processes occurred together, but strongly depended on the hydrological conditions. Between the PhuTho and SonTay sites, the important loss of SPM flux suggested a dominant deposition process in the floodplain during high water before the delta. These results proved the complex processes of erosion/sedimentation occurring on the Red River watershed.
EXPRESSION AND PURIFICATION CAPSID PROTEINS VP0, VP1 AND VP3 OF FOOT AND MOUTH DISEASE VIRUS TYPE O IN ESCHERICHIA COLI
Authors: Duong Nguyen Hoang , Chuang Chi-Ning , Hoa Nguyen Phuong , Dung Tran Thi Kim , Minh Le Hong , Anh Nguyen Mai , Kim Cuc Nguyen Thi , Ha Le Thu , Cuong Pham Viet , Fang Ting-Wang
Published: April 2018

Foot and mouth disease virus (FMDV) causing infectious disease affects broadly cloven-hoofed animals. It has 7 different serotypes. However O is the most prevalent type in 3 founded types (O, A, Asia1) recurrence in Vietnam fields. The current vaccine for FMDV is inactivated or attenuated forms. Vaccines were able to raise strong immune responses but still caused the safety concerns. Virus-like particles could be a new vaccine generation that fulfills the present questions. On the one hand, it can tackle the safety issues, on the other hand, it can reserve FMDV intrinsic form which will provoke high immunogenicity. The important initial step to make virus-like particles is expression the capsid proteins of FMDV in appropriate system. So this study we describe how to design, express and purify of all capsid proteins: VP0, VP1 and VP3 of O type FMDV isolated in Vietnam field using SUMO fusion expression system.
EVALUATION OF PROBITOIC POTENTIAL OF LACTOBACILLUS STRAINS FROM FERMENTED FOODS AND FEACES OF INFANTS
Authors: My Le Nguyen Thi , Huong Nguyen Thi
Published: April 2018

Lactobacillus strains are a major part of the probiotics, microflora of the intestine and of fermented foods. The aim of this study was to evaluate the potential probiotics of six Lactobacillus strains (L. fermentum 39-183; L. plantarum subsp.plantarum P-8; L. casei ATCC 334; L. rhamnosus ATCC 8530, L. brevis KB 290 and L. fermentum JMC 7776). Probiotic properties such as acid tolerance, bile resistance, bacteriocin-like activity, cell surface hydrophobicity and antibiotic resistance were assessed. In vitro results obtained showed that all Lactobacillus strains tested were able to meet the basic requirements for probiotic functions as they demonstrated probiotic characteristics such as tolerance to pH 2.0 and 2% bile salt. All Lactobacillus strains inhibited the growth of E. coli, Staphylococcus aureus and Salmonella Typhi. Among strains tested, L. plantarum subsp.plantarum P-8 showing inhibitory is very promising with inhibition zone ranging between 6.5 to 12.7 mm. The results for cell surface hydrophobicity and susceptibility against antibiotics also showed that L. fermentum JMC 7776 and L. plantarum subsp.plantarum P-8 had higher cell surface hydrophobicity than the rests.  All Lactobacillus tested were resistant to vancomycin and susceptible to streptomycin. The results obtained in this investigation will be used to select potentially probiotic strains for in vivo study
Development of Couette-Taylor Crystallizer in Cooling Crystallization: Promotion of Size Distribution of L-lysine
Authors: Trinh Huyen Thi Thanh , Nguyen Tuan Anh , Phan Thao Thanh , Khuu Quang Chau , Dang Giang Truong
Published: April 2018

The Couette-Taylor (CT) crystallizer was developed to promote the size distribution of L-Lysine crystal product in cooling crystallization. When using the CT crystallizer, the size distribution of crystal product was much narrower than that of the conventional Stirred tank (ST) crystallizer. Here, the coefficient size distribution (n) in CT crystallizer was quite large as 3.43, while it was only 2.17 in ST crystallizer at the same 360 rpm of agitation or rotation speed. This result indicated that the CT crystallizer was much more effective than the ST crystallizer in terms of the size distribution of L-lysine crystal products in cooling crystallization. The advantage of CT crystallizer over the ST crystallizer was explained in terms of the high energy dissipation of Taylor vortices flow, where it was 7.6 times higher than that of random fluid motion in conventional ST crystallizer. As such, the supersaturation profile in the CT crystallizer was much more homogeneous than that in the ST crystallizer, which resulted in promotion of size distribution L-lysine crystal product.
A STUDY ON KINETIC AND THERMODYNAMIC ADSORPTION OF FLUORIDE IN AQUEOUS SOLUTION ONTO ALUMINIUM HYDROXIDE COATED RICE HUSK ASH
Authors: Tuyen Tran Ngoc , Quyen Nguyen Duc Vu , Hai Ho Van Minh , Quang Tran Ngoc , Sy Hoang Trong , Liem Nguyen Trong
Published: April 2018

The fluoride adsorption on aluminum hydroxide coated rice husk ash material (RHA/Al(OH)3) was demonstrated in this study. The isothermal data indicated that the Langmuir model well described the adsorption system with the maximum monolayer adsorption capacity of 8.2 mg.g-1. The kinetic results revealed that the pseudo-second-order rate model fitted the experiments data better than the pseudo-first-order one. Furthermore, the adsorption of fluoride onto this material may be the chemical adsorption. Thermodynamic parameters (DG and DH) in the range of temperature from 30 to 70oC showed that the adsorption was a spontaneous and an endothermic process. RHA/Al(OH)3 could be used for well-treatment of fluoride contaminated well-water sampling in Ninhhoa district (Khanhhoa province). With the initial content of fluoride of 6.1 mg.L-1 and after 2 hours of treating with the dose of 4.0 ¸ 7.0 g.L-1, the concentration of fluoride in the samples decreased to 0.5 ¸ 1.5 g.L-1, that met acceptable limit of WHO.
ANTIOXIDATIVE DEFENSE RESPONSE TO APHID-INDUCED OXIDATIVE STRESS IN Glycine max (L.) Merr. cv. “Nam Dan”
Authors: Toan Tran Ngoc , Thanh Huyen Tran Thi Van , Chung Mai Van
Published: April 2018

Infestation of cowpea aphid (Aphis craccivora Koch) induced oxidative stress in leaves of soybean (Glycine max (L.) Merr. cv. “Nam Dan”) with a burst in generation of reactive oxygen species (ROS) products such as superoxide anion radical (O2.-) and hydrogen peroxide (H2O2) recorded around 24 hours after aphid feeding. An increase in content of thiobarbituric acid reactive substances (TBARS) in lipid peroxidation and a defined percentage of injury in aphid-infested leaves were resulted from the cellular oxidative damage. The enhanced activity of the antioxidant enzymes such as superoxide dismutase (SOD, EC 1.15.1.1) and catalase (CAT, EC 1.11.1.6) in leaves of soybean “Nam Dan” functions as the antioxidative response that controlled both ROS-generation to be enough levels to play as defensive element and ROS-detoxifying to reduce aphid-induced oxidative damage. The enhancement of SOD and CAT also can improve the tolerance of soybean “Nam Dan” to impact from A. craccivora.
Development of a PC Program for Multivariate Statistical Analysis
Authors: Son Pham Ngoc , Vu Cao Dong , Anh Mai Quynh
Published: April 2018

This report introduces a new computer program, having been developed initially at the Nuclear Research Institute at Dalat, for the multivariate data analysis techniques. In this preliminary version of the program, the size of a given data set to be analyzed is up to 50 variables and thousand observations, and can be used to perform some of the multivariate data analysis techniques such as principle component analysis, cluster analysis and data standardization. In comparison with other statistical analysis software, the same results are highly reproduced with MSAP.
Development of UV Laser Source Based on Distributed Feedback Dye Lasers Foruse in Measurement of Ozone in the Lower Atmosphere
Authors: Pham Minh Tien , Bui Van Hai , Duong Tien Tho , Dinh Van Trung
Published: April 2018

We conducted a study to develop a transmitter consisting of two Distributed Feedback Dye Lasers (DFDL) using Rhodamine 6G as an active medium, pumped by a frequency-doubled Nd:YAG laser (5ns, 10 Hz, 532 nm). The BBO crystals are used for frequency-doubling of DFDLs to generate UV missions. This system has been set up and it generates selected wavelenghts at 282.9 nm and 286.4 nm with the energy of 30 \(\mu\)J/pulse and 60 \(\mu\)J/pulse respectively. A DIAL system using this UV transmitter is designed to measure the vertical distribution of ozone with high temporal and spatial resolution. Our simulations of received DIAL signal indicate that the altitude of ozone distribution measurement can reach to over 5000 m along with range resolution of 100 m.
On-chip ZnO nanofibers prepared by electrospinning method for NO2 gas detection
Authors: Nguyen Van Hoang , Nguyen Van Dung , Do Quang Dat , Quan Thi Minh Nguyet , Chu Manh Hung , Nguyen Van Hieu
Published: April 2018

In the present study, on-chip ZnO nanofibers were fabricated by means of the electrospinning technique followed by a calcination process at 600 oC towards the gas sensor application. The morphology, composition, and crystalline structure of the as-spun and annealed ZnO nanofibers were investigated by field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD), respectively. The findings show that spider-net like ZnO nanofibers with a diameter of 60 – 100 nm were successfully synthesized without any incorporation of impurities into the nanofibers. The FESEM images also reveal that each nanofiber is composed of many nanograins. The combination of experimental and calculated X-ray diffraction data indicate that ZnO nanofibers were crystallized in hexagonal wurtzite structure. For the gas sensing device application, the ZnO nanofibers-based sensors were tested with the nitrogen dioxide gas in the temperature range of 200 oC to 350 oC and concentrations from 2.5 ppm to 10 ppm. The sensing property results indicate that at the optimal working temperature of 300 oC, the ZnO nanofibers-based sensors exhibited a maximum response of 30 and 166 times on exposure of 2.5 and 10 ppm NO2 gas, respectively. The presence of nanograins within nanofibers, which results in further intensification of the resistance modulation, is responsible for such high gas response.
Complete mitochondrial genome sequences of rare haplotype E4 from Phu Quoc ridgeback dog
Authors: Dũng Trần Hoàng , Mai Trương Nguyễn Thị Như , Công Nguyễn Thành , Hiếu Huỳnh Văn
Published: April 2018

Phu Quoc ridgeback dog is an invaluable species in Vietnam. The discovery of high-frequency rare halophytes E4 and E1 in Phu Quoc ridgeback dog while evaluate analyzing its genetic distances is an unexpected event. In this research, the primer-walking strategy was used to sequence the whole mtDNA of Phu Quoc ridgeback dogs carrying E4, B1 and E1 halophytes to explore trace of Phu Quoc ridgeback dog's origin. These mtDNA’s length (16,760 bp for PQ1 and 16,731 for PQ2) fall into the range of 16.7 kb, particularly, 16.760 bp in E4 dogs and 16.731 bp in B1 dogs and is basically similar to the ones of other dog breeds. The difference in length between E4 and B1 haplotype is mainly due to the difference of motif repeat frequency in the control region. The number of genes, starting and ending codes of E4’s mtDNA are similar to other common halophytes. Genetic distances between Phu Quoc ridgeback dogs' E1, E4 haplotypes and Pungsan dogs (EU789662) in the same clade in the phylogenetic tree are 0,072% and 0,24%, respectively, showing that Phu Quoc dogs with E haplotypes are very close relatively to Pungsan dogs in North-Korea. Although belonging to the same haplogroup, the genetic distance between Phu Quoc dogs E1 and E4 haplotype is 0,23%. In the other hand, genetic distances between E1, E4 haplotypes Phu Quoc ridgeback dogs and the closest grey wolves on phylogenetic tree are 0,3% and 0,1%, respectively. This is the first mitochondrial genome of E4 haplotype dogs to be sequenced and analyzed.
Application of DNA barcodes in identification of ginseng samples in the genus Panax L.
Authors: Hương Lê Thanh , Linh Nguyễn Nhật , Minh Bùi Mạnh , Hạnh Hà Hồng , Huệ Huỳnh Thị Thu , Hải Nông Văn , Huân Hà Văn , Hiền Lê Thị Thu
Published: April 2018

Identification of species based on DNA sequences (DNA barcodes) is an aid to a taxonomic classification using morphological characteristics. DNA barcoding uses standard short genomic regions that are universally present in target lineages and has sufficient sequence variation to identify species in the genus. A variety of loci has been suggested as DNA barcodes for plants, including genes and non-coding regions in the nuclear and plastid genomes such as psbA-trnH, matK, rbcL, and ITS. In this study, we evaluated five potential DNA barcodes including 18S, ITS, matK, psbA-trnH, and rbcL for their ability to distinguish between species across our samples in the genus Panax L. Multiple alignments with 41 GenBank sequences selected from 9 species showed that the 18S region had the highest level of average similarity (99.87 %), followed by rbcL, matK, psbA-trnH, and ITS regions with lower levels of average similarities (99.27 %, 98.66 %, 96.82 % and 96.50 %, respectively). The phylogenetic trees showed that four of eleven ginseng samples were Panax vietnamensis Ha et Grushv., and three samples were Panax stipuleanatus with bootstrap values of 100 %. However, sequences of all five screened loci in the last four samples, which were considered as Panax bipinnatifidus based on morphological characteristics, were highly similar to Panax stipuleanatus with the level of sequence similarity reached 99.81 % - 100 %. In addition, our results showed that of five investigated DNA regions, ITS, and psbA-trnH were the most promising barcodes that could identify P. vietnamensis Ha et Grushv. and P. stipuleanatus species within the genus Panax L.
Effects of simulated microgravity on seed germination, growth, development and accumulated secondary compounds of Hibiscus sagittifolius Kurz. cultured in vitro
Authors: Nhựt Dương Tấn , Tuấn Nguyễn Xuân , Anh Nguyễn Thị Thùy , Nam Nguyễn Bá , Huy Nguyễn Phúc , Tùng Hoàng Thanh , Hiền Vũ Thị , Luận Vũ Quốc , Vinh Bùi Thế , Luận Trần Công
Published: April 2018

In the present study, Hibiscus sagittifolius Kurz. seeds were used as the plant materials for studying on the effects of simulated microgravity (on a 2D clinostat) on seed germination, shoot multiplication, growth, development and secondary metabolite accumulation. After surface sterilization, seeds were cultured on MS medium supplemeted with 30 g/l sucrose and 9 g/l agar in Petri dishes (9 seeds per dish, the seed to seed distance of 1.5 cm and kept in the same direction), and maintained in a Clinostat (2 rpm). The results showed that simulated microgravity inhibited the growth and development of Hibiscus sagittifolius roots with root length of 11.83 cm, fresh and dry weight of 58.28 and 5.23 mg, respectively but it made an increase in germination rate (87%) and accumulation of secondary metabolites (the total saponins content of 53.00 mg/g and the total coumarin content of 25.67 mg/g) after 3 weeks of culture. In addition, the simulated microgravity also resulted in positive shoot multiplication (shoot height of 3.07 cm, 6.33 nodes per shoot, 3.33 shoots per explant, and the fresh and dry weight of 401.33 and 37.00 mg, respectively), and growth and development of Hibiscus sagittifolius shoots (plant height of 12.17 cm with 5.67 leaves per shoot together with the average root length of 1.77 cm, and the fresh and dry weight of 419.00 and 36.00 mg) after 4 weeks of culture. The results from this study could be attributed to future perspectives in research on plant breeding and accumulation of secondary metabolites in medicinal plants.
Effects of water shortage stress on the morphology and expression of the gene encoding dihydrodipicolinate synthase (DHDPS) in Mesembryanthemum crystallinum
Authors: Hồng Hoàng Thị Kim , Trang Phạm Thị Hồng , Phượng Trương Thị Bích , Thủy Nguyễn Thị Thu , Thu Ngô Thị Minh , Trang Nguyễn Thị Quỳnh
Published: April 2018

Lysine biosynthesis in plants has been studied extensively in order to improve the nutritional quality and provide the lysine for human life. In this process, dihydrodipicolinate synthase (DHDPS) is one of the important enzymes that determine the accumulation of lysine in plants. This paper presents the initial results of the effect of water stress on morphology and expression of gene encoding dihydrodipicolinate synthase (DHDPS) in Mesembryanthemum crystallinum leaves. M. crystallinum mature leaves have a lot of bladder cells which are surrounded and coated as the dewdrops sparkling on the outside of the leaves and twigs. When the external bladder cells of mature leaves were removed we can see a lot of stomata at both sides of the leaves under microscope with the objective lens 40 (Nikon, Eclipse 55I POL). When water stress treated after 5 days and 10 days, leaf morphology, cytoplasm and stomata of M. crystallinum mature plants were changed comparing with the control plants. The RNA was extracted from M. crystallinum leaves of both treated and untreated stress water samples. These RNA were used as a template to synthesize cDNA and analysis with specific primers by reverse transcription quantitative polymerase chain reaction (qRT-PCR). The results showed that water stress treatment had caused a change in the gene expression of DHDPH in treated plants significantly reduced the DHDPS gene expression in M. crystallinum leaves. In addition, a significant amount of DHDPS enzyme was measured in M. crystalium leaves, and the activity of that was changed by different water-stress treatment times.
Study on antifungal effect of oligochitosan fractions prepared by irradiation combined with chemical treatment on Colletotrichum capsici causing anthracnose in Capsicum
Authors: Dũng Phạm Đình , Thắng Nguyễn Tiến , Xô Dương Hoa , Luân Lê Quang
Published: April 2018

Chitosan was degraded by gamma rays irradiation method using 5% chitosan solution in 0.5% acetic acid with and without addition of 1% H2O2 for preparation of oligochitosan. The oligochitosan product with molecular weight (Mw) ~ 14.84 kDa prepared by radiation in combination with H2O2 treatment was used to fractionate into 5 different Mw fractions (F1: Mw < 1kDa, F2: Mw ~ 1-3 kDa, F3: Mw ~ 3-10 kDa, F4: Mw ~ 10-30 kDa và F5: Mw > 30 kDa) for testing its biological effects on red pepper plant (Capsicum frutescens L.). The obtained results showed that all separated fractions had the growth promotion effects on the increase of fresh biomass (9.9 - 56.3%) and chlorophyll content (20 - 92%) compared to those of the control one. In addition, the in vitro test of antifungal effect of separated fraction against C. capsici causing anthracnose on capsicum indicated that the fractions F3, F4 and F5 with Mw ≥ 3 kDa inhibited the growth of C. capsici colonies in a Potato Dextrose Agar (PDA) media at the concentration of 0.5%. While the the results from in vivo tests pointed out that the fractions F2, and F3 with the Mw in range of 1-10 kDa not only strongly stimulated the defense respose of tested plants to this pathogenic fungi causing anthracnose desease, but also the increased significantly gains of fruit biomass in 39 - 47%. Thus the oligochitosan fractions with Mw ~ 1-10 kDa are quite good products for both growth promotion efect as well as antifungal purpose for C. capsici causing anthracnose desease on capsicum.
Potential application on preparation for bio-fertilizer using Bacillus velezensis strains isolated from various regions in Vietnam
Authors: Trung Trịnh Thành , Vân Đinh Thị Tuyết , Liên Nguyễn Phương , Lương Đào Thị , Dương Văn Hợp Dương Văn Hợp Dương Văn Hợp
Published: April 2018

Bacillus velezensis is a species belonging to the bacterial group of B. subtilis species complex. Due to various beneficial traits to plants, the bacterium has been received considerable attention for application in disease control and crop productivity. In this study, we isolated 15 B. velezensis strains from various soils collected in regions of Hoang Lien, Cuc Phuong, Bach Ma, Chu Yang Sin and Con Dao. All of the strains demonstrated antagonistic activity against phythopathogenic fungi of Fusarium oxysporum, Sclerotium hydrophilum, Rhizoctonia solani and Phytophthora capsici and rice blight bacterium Xanthomonas oryzae. Those strains were capable of solubilizing Ca3(PO4)2 and producing plant growth hormone of indole acetic acid (IAA). Moreover, those strains produced a series of extracellular hydrolytic enzymes such as lipase, protease, amylase, CMCase, xylanase and chitinase. Analysis of genetic diversity based on rep - PCR fingerprinting technique showed that primer ERIC had greater discrimination than primer GTG5. Number of DNA banding patterns generated by primer ERIC and GTG5 were 8 and 13, respectively. Combination of DNA banding patterns of both primers showed 14 different genotypes among 15 B. velezensis strains. Using multilocus sequencing technique, genetic diversity was confirmed by a clear discrimination of strain CP 1604 and SP 1901 in two different clusters on phylogenetic tree. Due to the possession of many beneficial traits to plant growth, pesticide protection and production of many hydrolytic enzymes, the B. velezensis strains in this study have potential application on preparation of bio-fertilizer. Further investigation is needed in order to select an appropriate strain for this application.
Homoisopogon a from Ophiopogon japonicus induces apoptosis in A549 – a non small cell lung cancer cell line
Authors: Chung Nguyen Dinh , Dat Nguyen Tien , Anh Le Thi Van , Lee Jeong-Hyung , Dang Nguyen Hai
Published: April 2018

Lung cancer is the leading cause of death among Vietnamese people and can be divided into two major groups: small cell lung cancer (SCLC), and non-small cell lung cancer (NSCLC). It is estimated that 85% of patients was diagnosed as NSCLC. Therapy drugs that targeted lung cancer tumors with the epidermal growth factor receptor (EGFR) may initially provide benefit, but over time tumors can develop resistance. The recent discovery of EGFR-tyrosine kinase inhibitors (EGFR-TKIs) has provided a new target for the theurapeutic agents in non-small cell lung cancer treatment. In our study, homoisopogon A, a new compound isolated from the tubers of Ophiopogon japonicus (Mach mon, in Vietnamese) effectively showed the cytotoxic activity to the EGFR and TKI-resistant NSCLC cell lines including human lung carcinoma A549, human lung adenocarcinoma NCI-H1975 and human lung adenocarcinoma NCI-H1650. The IC50 values of homoisopogon A against A549, NCI-H1975 and NCI-H1650 were determined as 6.26, 19.51, and 24.66 µM, respectively. Preliminary study on the mechanism of action using flow cytometry analysis was performed. Homoisopogon A treatment of A549 cells at concentration of 25 μM generated apoptosis in 27.5% of cells (7% early apoptosis and 20.5% late apoptosis) after 24h of treatment. The effect increased significantly at the concentration of 50 μM, the homoisoflavanone generated apoptosis in 83.8% of cells (23.5% early apoptosis and 60.3% late apoptosis). Treatment with homoisopogon A for 48h also resulted in typical apoptotic morphological changes in A549 cells under microscopic observation. The results strongly suggested that homoisopogon A induces apoptosis in EGFR and TKI-resistant-A549 cells, thus resulting in the cytotoxicity.
The pathogenicity and reproduction capability of five epn strains on white grubs (Alissonotum impressicolle Arrow) in the laboratory conditions
Authors: Anh Đỗ Tuấn , Tiền Nguyễn Hữu , Châu Nguyễn Ngọc
Published: April 2018

Five entomopathogenic nematode strains, included 3 strains of the genus Steinernema, e.g. S-PQ16, SS-CP12 and S-TX1, and two strains of genus Heterorhabditis indica, e.g. H-CB3452 and H-KT3987 were evaluated on virulence and reproduction capacity on white grubs of black scarab (Alissonotum impressicolle Arrow) a serious pest damaging in the soils of sugarcane and many economic crops in Western Highland, particular Lam Dong province. The experiments were evaluated the pathogenicity virulence of EPN strains through establishing index as lethal concentration of 50 mortality percentage of host insects (LC50). While the reproduction capacity of EPN strains were established yield of infective juveniles (IJs) that produced inside insect cadavers. The bioassays on virulence of S-PQ16, S-CP12, S-TX1, H-CB3452 and H-KT3987 were revealed the mortality of white grubs as 93.3%, 86.7%; 93.3%; 86.7% and 73.3%, respectively, at the highest concentration of 5,000 IJs/insect. The 50% mortality of five indigenous strains was high levels with LC50 values ranged between 1,362 and 2,725 IJs. These values are also similar with our results previously on white grubs with some other EPN indigenous strains. It is also suitable with some evaluation bioassays of EPN on white grubs reported from China and Australia. The IJs yields from the insect cadavers were obtained up to 31×103 IJs with the strain S- CP12; 59.7×103 IJs with the S-PQ16 strain and 73.5×103 IJs with the strain S-TX1. Particularly, the highest yields were obtained from two strains of Heterorhabditis indica, viz. 125.1×103 IJs with H-KT3987 strain and 112.6×103 IJs with H-CB3452 strains. Respect to high virulence and also high reproduction capacity all these EPN strains should be satisfied the biological agents that can be used for biological control of white grubs of pests are living in the soil environment.
Influence of culture vessel volume and ventilation on in vitro culture and adenosine accumulation of Anoectochilus setaceus Blume
Authors: Luận Vũ Quốc , Nam Nguyễn Bá , Hiền Vũ Thị , Huy Nguyễn Phúc , Tùng Hoàng Thanh , Luận Trần Công , Nhựt Dương Tấn
Published: April 2018

Anoectochilus setaceus is a medicinal plant used as a traditional medicine as well as nutritious products for health care in China and many Asian countries. In conventional propagation, the the vessel type, material and volume lead to differences in the moisture content between the internal and external conditions which result in great impact on the quality of in vitro plantlets as well as subsequent growth at nursery. In this study, several factors affecting the multiplication and regeneration of A. setaceus cultured in vitro were investigated. The highest percentage of shoot regeneration (52.88%) from ex vitro stem nodes was obtained when explants were cultured on SH medium supplemented with 1 mg/l BA, 30 g/l sucrose with cotton wool plug as the substrate and pH of the medium was adjusted to 5.8 prior to autoclaving. In the present study, culture vessel volume and ventilation culture conditions indicated to have effect on shoot quality. Results showed that 3-liter Erlenmeyer flasks in combination with ventilation caps resulted in better shoot growth and development (shoot height: 10.75 cm; 9.45 leaves per shoot; fresh- and dry- weight of 2.45 and 0.219 g per shoot, respectively; leaf diameter: 2.85 cm and SPAD: 39.99). Results of chromatography (TLC) analysis indicated that explants gave the same Rf value as that of authentic Adenosine. Qualifying Adenosine using TLC showed that extracts of shoots cultured on solid and liquid medium (ventilation plastic bag), and that of shoots cultured in 3-liter vessel with liquid medium (with and without ventilation) gave the same pattern in the respects of color and Rf value.
Selecion of carrier material and substrate for biofertilizer by-product containing three halophilic plant growth promoting bacteria (Burkholderia cepacia BL1-10, Bacillus megaterium ST2-9 and Bacillus aquimaris KG6-3)
Authors: Nghĩa Nguyễn Khởi , Oanh Nguyễn Thị Kiều
Published: April 2018

In biofertilizer production, carriers and substrates have an important role in maintaining an efficacy of the commercial biofertilizer by-product. The aim of this study was to select the best carrier material and substrate and as well substrate’s moisture to sustainably store biofertilizer by-product containing three halophilic plant growth promoting bacterial strains. They are Bacillus aquimaris KG6-3 (KG6-1), Burkholderia sp. BL1-10 (BL1-10) and Bacillus megaterium ST2-9 (ST2-9) with a function of non-symbiosic nitrogen fixer, phosphorous solubilizing bacteria and IAA producing bacteria, respectively. All the experiments in this study were conducted under the laboratory conditions. Spent coffee ground and domestic coal ash were used as carrier materials. Besides that, rice bran, banana peel, banana flesh, cocopeat and brown sugar were used as substrate materials. The results showed that the domestic coal ash was able to sustain the highest viable cell number of ST2-9 and KG6-3 strains after 16 incubation hours whilst BL1-10 was found to be highest viable cell number in carrier material of spent coffee ground and the viable cell number of mixed inoculum including three bacterial strains was shown to be not significantly different among the three tested carrier materials. Moreover, the viable cell number of all three bacterial strains regardless of single or mixed inoculation was found to be highest during 15 weeks in rice bran substrate with 50% of moisture content. The mixed viable cell number of bacterial consortium achieved highest in the substrate containing rice bran + brown sugar (15:1, w/w) and when taking into account a comparion between two inoculation means, it was shown that the viable cell number in treatments with bacteria immobilized in domestic coal ash was always higher than that in treatments with free cell bacteria inoculation method. Thus, it was concluded that domestic coal ash and rice bran + brown sugar mixture (15:1) was the best carrier material type and substrate for biofertilizer by-product containing the three holophilic plant growth promoting bacteria and the immobilization technique to inoculate bacteria via carrier material was the best option for microbial inoculation.
A GRASP+VND Algorithm for the Multiple Traveling Repairman Problem with Distance Constraints
Authors: Bang Ban Ha
Published: April 2018

Multiple Traveling Repairman Problem (MTRP) is a class of NP-hard combinatorial optimization problems. In this paper, an other variant of MTRP, also known as Multiple Traveling Repairman Problem with Distance Constraint (MTRPD) is introduced. In MTRPD problem, a fleet of vehicles serve a set of customers. Each vehicle that starts from the depot is not allowed to travel a distance longer than a limit and each customer must be visited exactly once. The goal is to find the order of customer visits that minimizes the sum of waiting time. To the best of our knowledge, the problem has not been studied much previously, even though it is a natural and practical extension of the Traveling Repairman Problem or Multiple Traveling Repairman Problem case. In our work, we propose a metaheuristic algorithm which is mainly based on the principles of Greedy Randomized Adaptive Search Procedure (GRASP) and Variable Neighborhood Descent (VND) to solve the problem. The GRASP is used to build an initial solution which is good enough in construction phase. In a cooperative way, the VND is employed to generate diverse neighborhoods in improvement phase, therefore, it can prevent the search to escape from local optimal. Extensive numerical experiments on benchmark instances show that our algorithm can find the optimal solutions with up to 50 vertices in several instances. For larger instances, our algorithm obtains provably near-optimal solutions, even for large instances.
COLLABORATIVE RECOMMENDERATION BASED ON STATISTICAL IMPLICATION RULES
Authors: Phan Nghia Quoc , Dang Phuong Hoai , Huynh Hiep Xuan
Published: April 2018

In recent research, many approaches based on association rules have been proposed to improve the accuracy of recommender systems. These approaches are primarily based on Apriori data mining algorithm in order to generate the association rules and apply them to improving the recommendation results. However, these approaches also reveal some disadvantages of the system, such as taking a longer time for generating association rules; applying the Apriori algorithm on rating sparse matrix resulting in irrelevant information and causing poor recommendation results to target users and association rules generated primarily relying on given threshold of Support and Confidence measures leading to the focus on the majority of rules and ignoring the astonishment of rules to affect the recommendation results. In this study, we propose a new model for collaborative filtering recommender systems: The collaborative recommendation is based on statistical implication rules (IIR); Different from collaborative recommendation based on association rules (AR), the IIR predicts the items for users based on statistical implication rules generated from rating matrix and Implication intensity measures measuring the surprisingness of rules. To evaluate the effectiveness of the model, the experimental section is implemented on three real datasets to compare the results with some different effective models. The results show that the IIR has higher precision on the experimental datasets.
MULTI-OBJECTIVE EVOLUTIONARY ALGORITHMS: FOUNDATION, DEVELOPMENT AND OPEN ISSUES
Authors: Lâm Bùi Thu
Published: April 2018

Evolutionary computation (EC) has been a fascinating branch of computation inspiredby a natural phenomenal of evolution. EC enables computer scientists to design eective algorithmsdealing dicult problems. This paper focuses on a special class problem called multi-objective optimizationproblems and evolutionary algorithms designed for it. We will overview the development ofmulti-objective evolutionary algorithms (MOEAs) over the years and problem diculties and thenindicate the open problems in this area. Our chief goal is to provide readers reference material in thearea of multi-objective evolutionary algorithms
PHÂN LOẠI NỘI DUNG TÀI LIỆU WEB TIẾNG VIỆT
Authors: Phúc Trần Ngọc
Published: April 2018

Bài báo trình bày một số kết quả nghiên cứu, ứng dụng thuật toán Latent Dirichlet Allocation (LDA) phân tích chủ đề ẩn, để tìm tập đặc trưng cho các chủ đề áp dụng cho bài toán phân loại nội dung tài liệu web. Trong bài báo này các cụm danh từ được sử dụng để làm đặc trưng văn bản trong mô hình vector. Các bước thực hiện bao gồm thuật toán tách từ, gán nhãn từ loại để rút trích ra các cụm danh từ. Sử dụng phương pháp đếm tần suất từ và độ đo sự tương đồng cosine để tiến hành phân loại. Thuật toán Latent Dirichlet Allocation được sử dụng để tìm tập đặc trưng cho các chủ đề mà không cần quan tâm đến tần số xuất hiện, độ quan trọng của từ mà vẫn đưa ra bộ dữ liệu đầy đủ và chính xác. Kết quả đã cài đặt thử nghiệm vào bài toán phân lớp các tin tức phổ biến trên các trang báo tiếng Việt với độ chính xác khoảng 90% đáp ứng được mục tiêu phân loại đề ra.
ĐIỀU KHIỂN ON – OFF TRONG BÀI TOÁN DẦM CHỊU UỐN
Authors: Thăng Nguyễn Nhật
Published: April 2018

Ứng dụng nguyên lí cực đại Pontryagin xác định quy luật biến đổi của mặt cắt ngang dầm chịu uốn dưới tác dụng của trọng lượng bản thân cho giá trị cực đại của mũi tên võng. Kết quả nghiên cứu cho thấy điều khiển thích hợp có dạng On – Off  ứng với dầm có dạng bậc. Xác định điểm chuyển bậc và ảnh hưởng của tải đến vị trí điểm chuyển bậc đó.
NGHIÊN CỨU, LỰA CHỌN ĐIỀU KIỆN NUÔI CẤY VÀ LÊN MEN CHỦNG VI KHUẨN PSEUDOMONAS PUTIDA ĐỂ THU NHẬN ENZYME URICASE
Authors: Hà Phạm Thanh
Published: April 2018

Trong nghiên cứu này những điều kiện nuôi cấy tối ưu cho sinh tổng hợp uricase của chủng Pseudomonas putida CN3 đã được đánh giá. Kết quả chỉ ra rằng nhiệt độ 30 ºC, pH môi trường ban đầu 8, tốc độ lắc 250 vòng/phút, thời gian nuôi cấy 48 giờ là cần thiết cho chủng CN3 sinh uricase tối đa. Axit uric 0,5 % là cơ chất cảm ứng tốt nhất, glucose 0,5 % và cao nấm men 0,3 % là nguồn cacbon và nitơ tốt nhất cho sản sinh uricase từ P. putida CN3. Chủng P. putida CN3 lên men trong điều kiện nuôi cấy tối ưu trên thiết bị lên men 5 L sản sinh uricase có hoạt độ tổng 1,21 U/ml, hoạt độ riêng 1,33 U/mg trong thời gian ngắn chỉ 30 giờ, vì vậy chủng này có tiềm năng ứng dụng cao. điều kiện nuôi cấy, lên men, Pseudomonas putida, uricase.
TÁC DỤNG KHÁNG KHUẨN CỦA MÀNG POLYLACTIC ACID - NISIN
Authors: Thủy Trần Thanh
Published: April 2018

Màng polylactic acid (PLA) và nisin được tạo thành theo phương pháp phối trộn. Trong đó, polylactic acid và nisin đều là những sản phẩm có nguồn gốc từ vi sinh vật (từ chủng Rhizopus oryzae VLSH 01 và chủng L. lactis subsp. lactis PD15.1). Ảnh kính hiển vi điện tử quét (scanning electron microscopy – SEM) cho thấy nisin phân bố khá đồng đều trên màng. Nisin kết hợp vào trong màng PLA đạt 1415 IU/cm2. Bên cạnh đó, tác dụng kháng khuẩn của màng đã được nghiên cứu trên môi trường thạch bán lỏng và môi trường LB dịch thể. Kết quả cho thấy, màng PLA-nisin có tác dụng ức chế sinh trưởng của vi khuẩn kiểm định thuộc nhóm vi khuẩn Gram (+), đặc biệt đối với vi khuẩn gây bệnh trong thực phẩm gồm Bacillus cereus, Listeria monocytogenes và Staphylococcus aureus. Đồng thời, màng PLA-nisin có khả năng tiêu diệt hoàn toàn B. cereus ở nồng độ lây nhiễm ban đầu là 106 CFU/ml sau 16 giờ nuôi cấy. Kết quả nghiên cứu này đã cho thấy màng kháng khuẩn PLA-nisin có tiềm năng ứng dụng trong bao gói và bảo quản thực phẩm.
XÁC ĐỊNH CÁC THÔNG SỐ ĐỘNG HỌC CỦA FRUCTOSYLTRANSFERASE (FTS) BẰNG PHƯƠNG PHÁP MÔ PHỎNG LUYỆN KIM (SA - SIMULATED ANNEANING)
Authors: Ánh Lê Thị Hồng
Published: April 2018

Phương pháp mô phỏng luyện kim (SA – Simulated Anneaning) được giới thiệu một cách độc lập bởi S. Kirkpatrich, C. D. Gellatt, M. P. Vecchi năm 1983. Phương pháp này được xây dựng dựa trên mô phỏng kiểu Metropolis với các tham số điều khiển biến thiên theo chu trình tiến hóa của giải thuật. Đây là một công cụ hiệu quả để xử lí các bài toán tìm kiếm và tối ưu, đặc biệt là những bài toán có không gian tìm kiếm lớn.Trong bài báo này, chúng tôi đã xác định được các thông số động học của fructosyltransferase (FTS) bằng phương pháp mô phỏng luyện kim, giúp giảm thiểu số thí nghiệm, thời gian và chi phí khi nghiên cứu động học phản ứng enzyme, đặc biệt là trong trường hợp phản ứng có nhiều cơ chất.
ẢNH HƯỞNG CỦA MỘT SỐ YẾU TỐ CÔNG NGHỆ LÊN TÍNH CHẤT QUANG CỦA TINH THỂ NANO CuInS2
Authors: Thúy Nguyễn Thị Minh
Published: April 2018

Bài báo này trình bày kết quả nghiên cứu chế tạo tinh thể nanô CuInS2 (CIS) bằng phương pháp gia nhiệt, tạo phản ứng hình thành và phát triển tinh thể ở nhiệt độ cao trong dung môi diesel. Ảnh hưởng của các thông số công nghệ như nhiệt độ và thời gian phát triển tinh thể, tỉ lệ Cu:In trong các tiền chất lên tính chất quang (hấp thụ và huỳnh quang) của tinh thể nanô CIS, đã được nghiên cứu một cách có hệ thống. Cụ thể, đã khảo sát chất lượng tinh thể hình thành và phát triển trong khoảng 200 oC ÷ 230 oC, thời gian 15 phút và tỉ lệ Cu:In trong khoảng 0.5:1 ÷ 1.5:1. Từ các tính chất phổ hấp thụ và huỳnh quang, có thể thấy nhiệt độ chế tạo mẫu trong diesel tốt nhất là 210 oC. Chất lượng của các tinh thể nanô CIS tốt hơn khi bổ sung một lượng nhỏ Zn (<10 %) trong thành phần của tiền chất thể hiện ở bờ hấp thụ exciton rõ ràng hơn.
CHUYỂN BIẾN AUSFFERIT TRONG CÔNG NGHỆ CHẾ TẠO GANG CẦU TÔI ĐẲNG NHIỆT (ADI)
Authors: Dũng Nguyễn Hữu
Published: April 2018

Gang cầu truyền thống chỉ có thể đạt được các chỉ tiêu cơ tính như : độ bền kéo 700 - 750 MPa; độ giãn dài: 2 – 5 %. Để đạt được các cơ tính cao hơn, tất nhiên là độ tin cậy của sản phẩm cũng cao hơn, cần phải kiểm soát các thông số như: thành phần hóa học của hợp kim, chất lượng vật đúc, cấu trúc graphit và quá trình nhiệt luyện. Bài báo này giới thiệu một phương pháp chế tạo gang cầu tôi đẳng nhiệt (ADI). Cấu trúc gang cầu ADI bao gồm  pherit hình kim và austenit dư còn gọi là tổ chức ausferit. Cấu trúc này thể hiện sự kết hợp tuyệt vời về cơ tính: độ bền kéo 1200 MPa; độ giãn dài 7 – 8 %. Bài báo cũng sử dụng kết quả đo độ giãn nở nhiệt khi chuyển biến để tính toán các hệ số n và k trong phương trình Johnson–Mehl–Avrami và qua đó xây dựng giản đồ chuyển biến- nhiệt độ-thời gian. Cửa sổ quá trình trong trường hợp này được xác định là: tôi đẳng nhiệt ở 380 oC trong thời gian 2 giờ.
SPREAD OF INTERACTION IN NANOCOMPOSITE HARD/SOFT NANOSTRUCTURED MAGNETS
Authors: Hieu Nguyen Trung
Published: April 2018

In this study, the magnetic properties of 3D modeled two-phase hard/soft nanocomposite nanostructured magnets were simulated by means of the Monte-Carlo method. The dependences of the energy product and coercivity on the grain size and magnetically soft phase content were investigated. The influence of the interaction spreading in the soft phase on the magnetic properties was also discussed. The obtained results revealed that the energy product reaches an optimal value when the soft phase content ranges around 50 vol.%, and a strong magnetic interaction spreading locally along the Kneller-Hawig exchange length seems to be more important than a weak but widely spreading interaction.
NGHIÊN CỨU CẤU TRÚC VÀ TÍNH CHẤT TỪ CỦA HỆ HẠT NANO Co1-xZnxFe2O4 (x = 0 - 0,7) CHẾ TẠO BẰNG PHƯƠNG PHÁP THỦY NHIỆT
Authors: Nam Pham Hồng
Published: April 2018

Trong báo cáo này, các hạt nano Co1-xZnxFe2O4 (x = 0,0; 0,1; 0,3; 0,5 và 0,7) được tổng hợp bằng phương pháp thủy nhiệt với mục đích dùng cho ứng dụng nhiệt từ trị. Các đặc trưng cấu trúc, kích thước hạt và tính chất từ được khảo sát và đánh giá bằng nhiễu xạ tia X (XRD), hiển vi điện tử quét phát xạ trường (FESEM) và từ kế mẫu rung (VSM). Phân tích kết quả XRD cho thấy tất cả các mẫu thu được đều là đơn pha của cấu trúc spinel. Kích thước tinh thể trung bình thu được từ XRD (10 - 20 nm) là tương đương với kích thước hạt xác định từ các ảnh FESEM (12 - 23 nm). Sự thay đổi của từ độ bão hòa (Ms), các nhiệt độ chuyển pha như nhiệt độ khóa (TB), nhiệt độ Curie (Tc) và lực kháng từ (Hc) theo nồng độ Zn thay thế đã được khảo sát và biện luận. Chúng tôi cũng đã chỉ rằng hệ hạt Co0,3Zn0,7Fe2O4 là thích hợp nhất cho ứng dụng nhiệt từ trị.