The impact of oil prices, real effective exchange rate and inflation on economic activity: Novel evidence for Vietnam

The goal of this paper is to examine the impact of oil prices on Vietnam's economic activity using vector autoregressive (VAR) modeling and cointegration techniques. We use monthly data for the period 1995-2009 and include inflation and the real effective exchange rate as additional determinants of economic activity. We find evidence of a long-run relationship between oil prices, inflation, exchange rate, and economic activity. The results suggest that both oil prices and the real effective exchange rates have strongly significant impact on economic activity. An increase in oil price or depreciation may enhance economic activity. Vietnamese economic activity is influenced more by changes of value of Vietnamese currency than the fluctuations of oil prices. Inflation has a positive impact on economic activity however its impact is not highly significant. This suggests that moderate inflation is helpful rather than harmful to economic activity.Oil price, Economic activity, Vietnam

A thorough theoretical investigation into complexes formed by interaction of dimethyl sulfoxide with two water molecules

A computational study of the stability and the cooperative effect of hydrogen bonds in the complexes of dimethyl sulfoxide and two water molecules was undertaken at the MP2/6-311++G(2d,2p) level of theory. The cooperative energies of obtained complexes are significantly negative, indicating that there is a large cooperativity between types of hydrogen bonds. The existence of the O−H∙∙∙O hydrogen bond present at dimer of water increases the stability of O−H∙∙∙O and C−H∙∙∙O hydrogen bonds in the ternary complexes compared to relevant binary complexes. By vibrational and NBO analyses, it is found that the magnitude of stretching frequency red shift of O−H bonds in the O−H···O hydrogen bonds is enhanced, whereas the extent of stretching frequency blue shift of C−H bonds in the C−H∙∙∙O hydrogen bonds is weakened when the cooperativity of hydrogen bonds happens in the ternary complexes. Obtained results of AIM analysis and stabilization energies indicate the larger contribution of the O−H∙∙∙O relative to the C−H∙∙∙O hydrogen bond to cooperativity. Keywords. Dimethyl sulfoxide, hydrogen bond, cooperativity

Factors Affecting Consumers’ Intention in Vietnam-China Cross-border E-commerce: An Empirical Study in Hanoi, Vietnam

In the era of innovative technologies, the physical border is no longer a concern in exchanging goods thanks to the widespread use of internet connections. On this basis, the study explores the determinants that impact cross-border online consumers’ purchase intentions in Hanoi, Vietnam. As fundamental ideas, the Theory of Planned Behavior (TPB) and the Technology Acceptance Model (TAM) are integrated with the influence of the Regional Comprehensive Economic Partnership (RCEP). The examined factors consist of Consumer Attitude, Subjective Norms, Perceived Behavioral Control, Perceived Usefulness, Perceived Ease of Use, Perceived Risk, Trust, and RCEP. The research was conducted on a survey questionnaire of 253 online shoppers in Hanoi who have experienced cross-border purchasing. The data was processed using several statistical methods, namely descriptive statistics, exploratory factor analysis (EFA), correlation analysis, and regression analysis. The analysis reveals that Consumer Attitude, Subjective Norms, Perceived Behavioral Control, Perceived Usefulness, Perceived Ease of Use, and Trust have a positive influence on the consumer’s intention to cross-border e-commerce (CBEC), while perceived risk and RCEP do not exert any force on the intention. Among these variables, Risk perception and trust have been demonstrated to have the most significant impact on online purchase intention. The outcomes of the study indicate that online retailers or intermediaries adopt a third-party payment processor and publish policies to protect consumers’ private information. It is also suggested that the government should educate the public on the benefits of RCEP, implement the relevant policies, and provide guidance for the sellers to follow to utilize the advantages of RCEP

Deep Transfer Learning: A Novel Collaborative Learning Model for Cyberattack Detection Systems in IoT Networks

Federated Learning (FL) has recently become an effective approach for cyberattack detection systems, especially in Internet-of-Things (IoT) networks. By distributing the learning process across IoT gateways, FL can improve learning efficiency, reduce communication overheads and enhance privacy for cyberattack detection systems. Challenges in implementation of FL in such systems include unavailability of labeled data and dissimilarity of data features in different IoT networks. In this paper, we propose a novel collaborative learning framework that leverages Transfer Learning (TL) to overcome these challenges. Particularly, we develop a novel collaborative learning approach that enables a target network with unlabeled data to effectively and quickly learn knowledge from a source network that possesses abundant labeled data. It is important that the state-of-the-art studies require the participated datasets of networks to have the same features, thus limiting the efficiency, flexibility as well as scalability of intrusion detection systems. However, our proposed framework can address these problems by exchanging the learning knowledge among various deep learning models, even when their datasets have different features. Extensive experiments on recent real-world cybersecurity datasets show that the proposed framework can improve more than 40% as compared to the state-of-the-art deep learning based approaches.Comment: 12 page

Cloning and expression of pigC gene in Escherichia coli

Prodigiosin (Pg), which is particularly of interest because of anticancer and antimicrobial activities, can be produced through the PigC-catalyzed condensation reaction of 4-methoxy-2, 2’-bipyrrole-5-carboxyaldehyde (MBC) and 2-methyl-3-amylpyrrole (MAP). Therefore, the PigC protein plays an important role in prodigiosin biosynthetic pathway. However, studies related to PigC protein have not been carried out in Vietnam yet. In this work, the pigC gene was cloned and expressed in Escherichia coli DH10B and BL21 (DE3), respectively. Using PCR and universal primers, we amplified a fragment of 3 kb covering entire coding region of the pigC gene from Serratia sp. strain M5. The pigC gene was inserted into pJET1.2 vector, and then transformed into E. coli DH10B. The sequence of a recombinant vector pJET1.2/pigC was evaluated by using whole colony PCR amplification. Sequence alignment results revealed that the obtained pigC gene possesses 71.5% and 75.4% of nucleotide identity in comparison with two strains, Serratia 39006 and Serratia sp. AS9 published in GenBank with their respective accession numbers of AJ833001 and CP002773. The recombinant vector pJET1.2/pigC was used to reamplify pigC, and the acquired amplicon was inserted into pET22b vector at the site of HindIII and XhoI. The clone E. coli BL21 (DE3) containing recombinant vector pET22b/pigC was expressed in the auto-induced medium. The presence of PigC protein in the lysate was identified as a 100 kDa band through Western Blot analysis using anti his-tag antibody. Afterward, the PigC protein was purified by Ni-NTA column, and its expression level was quantified through SDS-PAGE analysis. The results of our study provide a potential material for producing prodigiosin from recombinant protein in Vietnam

How Digital Natives Learn and Thrive in the Digital Age: Evidence from an Emerging Economy

As a generation of ‘digital natives,’ secondary students who were born from 2002 to 2010 have various approaches to acquiring digital knowledge. Digital literacy and resilience are crucial for them to navigate the digital world as much as the real world; however, these remain under-researched subjects, especially in developing countries. In Vietnam, the education system has put considerable effort into teaching students these skills to promote quality education as part of the United Nations-defined Sustainable Development Goal 4 (SDG4). This issue has proven especially salient amid the COVID−19 pandemic lockdowns, which had obliged most schools to switch to online forms of teaching. This study, which utilizes a dataset of 1061 Vietnamese students taken from the United Nations Educational, Scientific, and Cultural Organization (UNESCO)’s “Digital Kids Asia Pacific (DKAP)” project, employs Bayesian statistics to explore the relationship between the students’ background and their digital abilities. Results show that economic status and parents’ level of education are positively correlated with digital literacy. Students from urban schools have only a slightly higher level of digital literacy than their rural counterparts, suggesting that school location may not be a defining explanatory element in the variation of digital literacy and resilience among Vietnamese students. Students’ digital literacy and, especially resilience, also have associations with their gender. Moreover, as students are digitally literate, they are more likely to be digitally resilient. Following SDG4, i.e., Quality Education, it is advisable for schools, and especially parents, to seriously invest in creating a safe, educational environment to enhance digital literacy among students

In vitro antioxidant activity and content of bioactive compounds from Homalomena occulta

Homalomena occulta, a plant widely used in traditional Vietnamese medicine, was assessed for its antioxidant potential through DPPH radical scavenging and total antioxidant capacity methods. The results showed that Homalomena occulta exhibited significant antioxidant activities with a low IC50 value of 40.27 μg/mL, which is comparable to that of curcumin (38.50 μg/mL). Furthermore, the total antioxidant capacity of the Homalomena occulta extract was determined to be 77.48 ± 2.34 mg GA/g. To investigate the composition of the plant, various compounds including total phenolic, total flavonoid, polysaccharides, and triterpenoids were quantified using colorimetric methods with specific reagents. The content of phenolic compounds, flavonoid compounds, polysaccharides, and triterpenoids in Homalomena occulta was found to be 36.87 ± 0.42 GAE/g, 26.83 ± 0.29 mg QUE/g, 5.06 ± 0.06%, and 52.09 ± 1.77 mg Olenanoic/g, respectively. Notably, this study provides the first-ever report on the polysaccharide and total triterpenoid content of Homalomena occulta

Polysaccharide extraction from Myxopyrum smilacifolium trunk and its antioxidant capacity

As a traditional medicinal plant in Vietnam, Myxopyrum smilacifolium has been used for a long history to treat cough, nervous disorders, numbness, rheumatism, and cephalalgia. Nevertheless, reports on the antioxidant activity and extraction of M. smilacifolium polysaccharides are still very rare. This study was designed to extract a high yield of polysaccharides from the M. smilacifolium trunk and characterize it. As a result, the maximum yield of the polysaccharides of 5.13 ± 0.05% was obtained with an extraction time of three hours, extraction temperature of 100 oC, the ratio of water to sample of 1:50 as extraction solution, extraction number of times 3, and the ratio of ethanol to extract volume 5:1 (v/v). Polysaccharides was characterized by Fourier transform infrared spectroscopy (FT-IR) and high-performance gel-permeation chromatography (HPGPC). The average molecular weight of extracted polysaccharides was around 3.78 × 105 Da. In vitro assays dan impressive antioxidant activities of the extracted polysaccharides, containing 0.2423 ± 0.0028 mg GA/g or 0.2142 ± 0.0007 μmol AS/g. The IC50 values of polysaccharides in the DPPH and ABTS methods were 0.89 mg/mL and 3.85 mg/mL, respectively.  These findings exhibited the potential for application or further research and development of polysaccharides from Myxopyrum smilacifolium

Quality of cookies supplemented with various levels of turmeric by-product powder

Starch production from turmeric (Curcuma longa) generates residue, which contains different nutrients, dietary fiber, and antioxidants. In this study, the by-product of turmeric starch production was dried at 50 ℃ to a moisture content of 11–12%, milled, passed through a 70-mesh sieve, and then added to cookie formulation to increase antioxidant content and activities of the fortified cookies. The ratio of turmeric by-product powder (TBP) in the cookie formulation was varied from 0 to 12%. The greater the TBP ratio in the cookie recipe was, the greater the contents of ash and dietary fiber and the antioxidant activities of the fortified cookies. At 12% TBP level, the total phenolic content, flavonoid content, 2, 2-diphenyl-1-picrylhydrazyl scavenging activity, and ferric reducing antioxidant power of the fortified cookies were increased by 6.4, 5.5, 4.7, and 6.8 times, respectively, as compared to those of the cookies without TBP supplementation. The increase in TBP ratio also enhanced the product hardness and reduced its diameter, thickness, and overall acceptability. The cookies with 9% TBP ratio were rich in antioxidants and the sensory quality was acceptable. Turmeric by-product powder was a good ingredient for antioxidant fortification in cookie products

THIẾT LẬP CHỈ SỐ CHẤT LƯỢNG NƯỚC DỰA VÀO PHÂN TÍCH THỐNG KÊ: ÁP DỤNG CHO SÔNG HƯƠNG, TỈNH THỪA THIÊN HUẾ

Huong River’s water quality was preliminarily assessed by comparing the parameters monitored with the Vietnam Technical Regulation on Surface Water Quality. The river water quality was then assessed based on Water Quality Index (WQI). Principal Component Analysis (PCA) was applied to the river water quality data during 2017–2020 to determine the weighting (wi) of the ith water quality parameter for WQI calculation. The WQI was calculated both from wi and subindex (qi). The parameters selected (n = 11) for WQI calculation consisted of pH, EC (electric conductivity), DO, TSS, BOD5, COD, N-NH4+, N-NO3–, P-PO43–, Fe (total dissolved iron), and TC (total coliform). The parameters were monitored at 8–10 sites in 4–5 sessions (February, May, August, and November). The results show that 95% of WQI at 90–100 corresponds to water quality level ‘good’ and ‘excellent’; only 5% of WQI values at 49–77 (mainly in November 2020) corresponds to the level from ‘bad’ to ‘good’. In the flood-rainy season, the increase in concentrations of TSS and Fe and the decrease in DO concentration lead to a reduction in WQI. The river water quality was not significantly differed by space/monitoring sites (p > 0,05) with median WQIs of 97–100 but varied over time: the years 2017 and 2019 had median WQIs (99), higher than that in the years 2018 and 2020 (97) with p < 0,01.Chất lượng nước (CLN) sông Hương được đánh giá sơ bộ qua so sánh các thông số quan trắc với quy định kỹ thuật Việt Nam về CLN mặt. Tiếp theo, CLN sông được đánh giá qua Chỉ số chất lượng nước (WQI). Phương pháp phân tích thành phần chính (PCA) được áp dụng cho dữ liệu CLN sông giai đoạn 2017–2020 để xác định trọng số (wi) của thông số CLN i trong tính toán WQI. Chỉ số chất lượng nước được tính từ cả trọng số và chỉ số phụ (qi). Các thông số được lựa chọn để tính WQI gồm (n = 11): pH, EC (độ dẫn điện), DO, TSS, BOD5, COD, N-NH4+, N-NO3–, P-PO43–, Fe (tổng sắt tan) và TC (tổng coliform). Các thông số đó được quan trắc ở 8–10 vị trí trong 4–5 đợt (tháng 2, 5, 8 và 11). Kết quả cho thấy, 95% các giá trị WQI nằm trong khoảng 90–100, ứng với CLN loại ‘tốt’ và ‘rất tốt’; chỉ 5% các giá trị WQI nằm trong khoảng 49–77 (chủ yếu vào tháng 11/2020), ứng với CLN loại ‘xấu’ đến ‘tốt’. Vào mùa mưa lũ, nồng độ TSS và Fe tăng lên, nồng độ DO giảm, dẫn đến làm giảm WQI. Chất lượng nước sông không khác nhau có ý nghĩa thống kê theo không gian/vị trí quan trắc (p > 0,05) với WQI trung vị 97–100 nhưng khác nhau theo thời gian: năm 2017 và 2019 có WQI trung vị (99) lớn hơn năm 2018 và 2020 (WQI trung vị 97) với p < 0,01