Published: 2020-07-31

Acute toxicity, antibacterial and antioxidant abilities of Elephantopus mollis H.B.K. and Elephantopus scaber L.

Nguyen Trong Hong Phuc, Do Tan Khang, Nguyen Thi Thuy Nhien, Phan Thanh Dat, Phung Thi Hang
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Elephantopus mollis H.B.K.,and Elephantopus scaber L. were collected at To mountain in An Giang province and assessed for extraction efficiency, resistance ability to common bacterial strains in humans and animals, antioxidation, and toxicity. The extraction efficiency of two species was 11-26% and 16 – 28%, respectively and depending on the part of the plant. The flowers of both species had better antioxidant results than other parts with EC50 at 32.2051 mg/mL and 59.9778 mg/mL, respectively, which was highly different from the rest of the plant (p). The leaves of both species had higher antibacterial properties than the other parts. For the six bacterial strains tested, both studied species had the strongest inhibiting ability for the growth of E. coli. (at a concentration of 200 mg/mL) different from that of Ampicillin (p). These two species were not toxic to Mus musculus at the dose of 8000 mg/Kg.

EFL teachers’ perceptions of the use of e-textbooks at secondary schools in Dong Thap province

Dinh Thanh Hung, Le Xuan Mai
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This descriptive quantitative study is aimed to investigate the EFL teachers’ perceptions of using e-textbooks in EFL classes at lower-secondary schools in Dong Thap province and what they perceived in terms of the benefits and challenges in using the digital version of the current textbooks. The data were collected through thirty-five Likert scale items and two open-ended questions in the form of online questionnaire from 155 EFL teachers at twelvelower-secondary schools in Dong Thap province. The findings showed that the participants’ perceptions towards applying e-textbooks in their EFL classes are highly positive. These teachers agreed that using e-textbooks is not only convenient for them in teaching but it also has positive effects on enhancinglearners’ English vocabulary, pronunciation and communication competence thanks to the vivid interactive features of the digital version of the current textbooks. In addition, teachers in urban schools have a higher tendency of using e-textbooks than those in the rural ones. Moreover, the results also showed that e-textbooks will be difficult to be applied in the case of unstable internet connection and lack of digital facilities. In addition, it is necessary for teachers to update their technological skills and prepare the lesson plans under the use of e-textbooks to make their teaching practices effectively.

Employability attributes of interpretation and translation students in Vietnam

Phuong Hoang Yen, Huynh Van Hien
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Universities need to capture the current state of graduate employability from graduates’ perspectives if they are to respond effectively to skills and knowledge requirements of the industry. Globally, graduate employability is a concept that is becoming increasingly popular in higher education sector. Therefore, this paper aims to explore employability attributes that graduates of English translation and interpretation (ETI) program need. A survey with 48 EIT alumni of a university in the Mekong Delta of Vietnam reveals the attributes that are important for the job market and those that graduates need more training on. The findings revealed that ETI students not only need to reinforce their English linguistic knowledge, professional knowledge and other skills and knowledge provided in the training program, but also have to develop ‘key’ employability skills such as, communication, social and cultural skills in order to be ready for the labor market.

Inhibitory effects of cinnamon oil, acetic acid, and lactic acid on Escherichia coli ATCC 23631

Lieu My Dong, Dang Thi Kim Thuy
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In this study, the antimicrobial activities of cassia oil (Cinnamomum cassia), acetic acid, and lactic acid, alone or in combination, against Escherichia coli ATCC 23631 were evaluated by the agar disk diffusion, broth dilution, and UV absorption determination methods. In the agar disk diffusion assays using the antibiotics ampicillin and nalidixic acid as the positive control, all three agents tested exhibited an effective inhibition against E. coli with inhibition zones ranging from 3.00 to 15.33 mm, compared to those of ampicillin and nalidixic acid ranging from 0.00 to 12.00 mm. In the broth dilution assays, the MBC (Minimum bactericidal concentration) values of cassia oil and organic acid were determined from 300 to 5.000 ppm in which cassia oil giving the best result. In both assays, acetic acid and lactic acid showed similar antimicrobial activities, which are lower than those of cassia oil or their combinations. The assays also suggested that the combinations of cassia oil and lactic acid showed a higher synergic effect than those of cassia oil and acetic acid. Although the antimicrobial activities of the combinations of cassia oil with the organic acids were not higher than using the pure oil, the use of these combinations would reduce the essential oil amount needed to inhibit E. coli.

Separation and recovery of Co(II) and Li(I) from spent lithium-ion mobile phone bat-teries

Nguyen Thi Hong, Duong Thi Hong Nhung
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In the present work, a process for recovery of Co(II) and Li(I) from spent lithium-ion mobile phone batteries was developed by using leaching, precipitation and solvent extraction. The leaching efficiency of Co(II) and Li(I) was investigated with respect to HCl concentration, temperature, and time. Most of Co(II) and Li(I) were dissolved from spent lithium-ion batteries under optimum leaching conditions: 4 M HCl, 50oC, 1.5 hrs and pulp density of 10 g/L. Seperation and recovery of Co(II) and Li(I) from the HCl leaching solution can be carried out by precipitation and solvent extraction. Cobalt oxalate was precipitated from the HCl leaching solution by adding oxalic acid at pH = 3, leaving Li(I) in the aqueous solution. In the case of solvent extraction, trioctylamine (TOA) was used to selectively extract Co(II) over Li(I) from the HCl leaching solution, and then Co(II) from the loaded TOA was stripped using distilled HCl solution. In term of recovery efficiency of Co(II) and loss of Li(I), precipitation was recommended as a suitable method to separate and recover Co(II) and Li(I) from the leaching solution of spent lithium-ion mobile phone batteries.

Forecasting time series with long short-term memory networks

Nguyen Quoc Dung, Phan Nguyet Minh, Ivan Zelinka
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Deep learning methods such as recurrent neural network and long short-term memory have attracted a great amount of attentions recently in many fields including computer vision, natural language processing and finance. Long short-term memory is a special type of recurrent neural network capable of predicting future values of sequential data by taking the past information into account. In this paper, the architectures of various long short-term memory networks are presented and the description of how they are used in sequence prediction is given. The models are evaluated based on the benchmark time series dataset. It is shown that the bidirectional architecture obtains the better results than the single and stacked architectures in both the experiments of different time series data categories and forecasting horizons. The three architectures perform well on the macro and demographic categories, and achieve average mean absolute percentage errors less than 18%. The long short-term memory models also show the better performance than most of the baseline models.

Al2TiO5/SBA-15 promoting photocatalytic degradation of cinnamic acid

Nguyen Dien Trung, Nguyen Thi Hong, Mai Van Hieu, Nguyen Thanh Nhuan
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The synthesis of Al2TiO5/SBA-15 (ATO/SBA) catalysts was investigated by the sol-gel method using precursors including aluminum nitrate, titanium isopropoxide, SBA-15, and citric acid. The formation of ATO/SBA phases was analyzed by X-ray diffraction (XRD). The content of ATO in ATO/SBA catalysts strongly affected the photocatalytic degradation of cinnamic acid (CA). The obtained results showed that 75% ATO in ATO/SBA (75ATO/SBA ) phases led to the highest efficiency of CA photodegradation. The characteristics of 75ATO/SBA sample were determined by Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller adsorption, UV-Vis diffuse reflectance spectroscopy, and transmission electron microscopy. Moreover, the activity of 75ATO/SBA on photocatalytic degradation of CA was also investigated by catalyst dosage, initial pH of CA solution, and airflow rate. The optimum condition for photodegradation efficiency of CA was found to be at Ccat = 0.75 g/L, pH = 3.8, Qair = 0.3 L/min and treact = 6 hrs.

A new natural jasmonoid glucoside isolated from Euphorbia hirta L. extract

Le Thi Bach, Bui Thi Buu Hue, Le Tien Dung, Nguyen Trong Tuan
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Euphorbia hirta L., one of the species belonging to the genus Euphorbia, Euphorbiaceae family, is common in the Mekong Delta of Vietnam. The present study was designed to investigate the phytochemicals of Euphorbia hirta L. collected in Can Tho city. Repeated chromatography of the methanol fraction on silica gel columns afforded a jasmonoid glucoside sodium salt, a new compound, while four known compounds were isolated from ethyl acetate extract. Their structures were elucidated by analysis of spectral data and in comparison with the published literature data.

Docking belinostat into HDAC 8 using autodock tool

Huynh Nhu Thao, Bui Thi Buu Hue, Le Thi Bach, Tran Quang De, Ha Thi Kim Quy, Nguyen Thanh Si, Nguyen Huu Toan, Nguyen Cuong Quoc, Nguyen Trong Tuan
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Belinostat, a histone deacetylases inhibitor, was reached the marketing approval by FDA for the treatment of relapsed and refractory peripheral T-cell lymphomas in 2014. Among 18 Histone Deacetylase (HDAC) enzymes, HDAC 8 has grabbed considerable attention from chemists as a promising target for cancer treatment, which leads to an ever-growing demand for the discovery of novel HDAC 8 inhibitors. With the advent of technologies, a useful and free-of-charge software – Autodock Tool was introduced to dock belinostat into the active site of HDAC 8 in this report. Nevertheless, docking to HDACs, known as metalloenzymes, still remains a challenge due to the interaction with Zn2+ ion at the bottom of the active binding site of the enzyme. For this reason, the extension of the Autodock forcefield to the new one named Autodock4Zn was utilized. The outcomes showed significant improvements in performance in both free energy of binding estimation as well as binding capacity of belinostat with different amino acids of HDAC8.