A study on the corrosive inhibition ability of CT3 steel in 1 M HCl solution by caffeine and some characteristics of the inhibition process

Caffeine was isolated from dry green tea leaves and used as corrosion inhibitor. The aim of this paper is to study the corrosion inhibition behavior of caffeine with its different concentrations (from 0.01 g/L to 3.00 g/L) for CT3 steel in 1M HCl solution by the curve polarization measurements and surface examination studies. Experiment result showed that: as the concentration of caffeine increases, the inhibition efficiency increases; %IE max is approximately 83.27% at concentration of caffeine 3.00 g/L. The experimental data from all measurements was found to  fit well with the Langmuir caffeine adsorption isotherm. Calculated values of free energy of adsorption DGads are -14.71 kJ/mol. It shown that, the adsorption is spontaneous and consistent with the mechanism of physical adsorption. It showed that, the adsorption is spontaneous and consistent with the mechanism of physical adsorption. As temperature increase from 298 to 318 K, the inhibition efficiency is relatively stable: decrease slightly from 83.27 % down 78.50 %. Calculated values of the heat of adsorption DHads are ranged from -6.38 kJ/mol to -19.89 kJ/mol, indicating  that  the adsorption of caffeine on the surface of CT3 steel is exothermic. The increasing of activation energy  in corrosion process which presents caffeine 3.00 g/L compared to absent caffeine proved that caffeine have corrosion occurred more difficult

Artefactual Suboptimal Fixation Effect to Nuclear Staining on Erythrocytes of Lutjanus kasmira (Forsskål 1775)

This research presents the unusual staining characteristic of the teleosts red blood cells–the common bluestripe snapper Lutjanus kasmira, caught at Toc Tan (Allison) Reef, Truong Sa Archipelago, Vietnam, due to side effects of the delayed staining procedure. In addition to the quantitative data measured, the results of microscopic image research showed that, on slides performed with the delayed Romanovsky staining procedure using Giemsa dye, the cell "nucleus" was not dye-stained as seen in the erythrocytes of much other fish. The AFM and SEM images of blood slides show that the structure of the nuclear zone and the nuclear membrane was destroyed. Although methanol is used as one of the common fixatives in biology, the delayed staining still causes artifactual side effects, disrupts the structure of the red blood cell nucleus and can cause confusion when studying cytogenetics

Factors Affecting Cooperation in the International Supply Chain of Seafood Enterprises: the Case of Vietnamese

Purpose: The purpose of this research is to analyze and evaluate factors affecting cooperation in the international supply chain of Vietnamese seafood enterprises.   Theoretical framework: Operations in international business context are associated with high risks, so cooperation in supply chain helps to improve management flexibility. On the other hand, acccording to the theory of resource dependency, resource sharing and information sharing strategies can affect the quality and the level of cooperation among supply chain partners.   Design/methodology/approach: To achieve the aim of this study, a literature survey related to supply chain and supply chain cooperation is carried out, and empirical analysis is conducted among 327 partners in seafood industry with the results analyzed using Cronbach’s Alpha analysis, exploratory factor analysis (EFA), and linear regression analysis (RA).   Findings: Research results have confirmed that there are six main factors directly affecting the international supply chain cooperation of Vietnamese seafood enterprises including: (1) Trust; (2) Power; (3) Distance; (4) Government policy; (5) Cooperation strategies and (6) Information sharing.   Research/Practical & Social implication: The encouraging policies and simplified export regulations are to be implemented by the government, VASEP and enterprises so the knowledge about international supply chain cooperation will be promoted with the help of comprehensive future research directions.   Originality/value: This is literally one of the first research works in Vietnam to incorporate the information sharing component into the model of affecting factors for international supply chain cooperation. Regardless of business uncertainties, the study shed new light on supply chain cooperation and promote firms to gain an edge in the global marketplace

POTENTIAL INTOXICATION BY TOXIC CYANOBACTERIA AND THEIR TOXINS IN SOME VIETNAMESE FRESH WATERBODIES

Joint Research on Environmental Science and Technology for the Eart

Miliutine A acid, a new cyclofarnesane sesquiterpene from the stems of <i>Miliusa velutina</i>

Six compounds were isolated from the ethyl acetate extract of the stems of Miliusa velutina, including miliutine A acid (1), a new cyclofarnesane sesquiterpenoid; miliutine B methyl ester (2), a cyclofarnesane sesquiterpenoid which was determined the absolute configuration for the first time and four known phenol derivatives (3–6). NMR spectroscopic and mass spectrometry were used for identifying relative configurations. The assignments of the absolute configurations were determined based on Electronic Circular Dichroism (ECD) and NOESY spectra analysis. All six compounds were screened for their in vitro cytotoxic activities against HepG2 cell line using the SRB assay and they showed weak or none activities.</p

The Impact of Viral Marketing on Emotion and Impulse Buying Behavior: A Case Study of Online Fashion

Impulsive online shopping is becoming a habit for many young consumers, especially for fashion products. This study aims to analyze the influence of viral marketing on emotions and impulsive online shopping behavior of young people for fashion products in Vietnam. The results showed that viral marketing with characteristics such as entertainment, source credibility, visual appeal, informativeness, and irritation all had a significant impact on emotions and impulsive online shopping behavior. Therefore,some suggestions are proposed for applying viral marketing to promote impulsive online shopping behavior for fashion products. Keywords: Viral marketing, Impulse buying behavior, Online shopping, Emotions, Fashion. DOI: 10.7176/EJBM/15-7-03 Publication date: April 30th 202

TÀI SẢN THƯƠNG HIỆU BÁO ĐIỆN TỬ VIỆT NAM: TỪ HÀI LÒNG ĐẾN TRUNG THÀNH THƯƠNG HIỆU

The study analyzes the intricate relationship between Brand Awareness, Brand Trust, Perceived Value, Brand Satisfaction, and Brand Loyalty in the context of e-newspaper brands in Vietnam. Data was collected in both face-to-face and online forms from 303 e-readers of the most popular e-newspapers nowadays, as follows: VnExpress, Dantri, VietNamNet, Tuoi Tre, and Thanh Nien. Collected data are filtered, processed, and analyzed by the PLS-SEM structural model using the SmartPLS tool. The research results have provided an empirical basis for the positive impact of factors influencing brand loyalty and the mediating role of brand satisfaction in the context of e-newspaper brands in Vietnam, thereby contributing enormously to the theoretical basis of the brand equity model.Nghiên cứu phân tích mối quan hệ phức tạp giữa các yếu tố Nhận thức thương hiệu, Niềm tin thương hiệu, Giá trị cảm nhận, Hài lòng thương hiệu và Trung thành thương hiệu trong bối cảnh thương hiệu báo điện tử ở Việt Nam dựa trên lý thuyết về mô hình tài sản thương hiệu CBBE (Customer-based Brand Equity). Dữ liệu điều tra được thu thập bằng hình thức trực tiếp và trực tuyến đối với 303 độc giả số của các trang báo điện tử phố biến nhất hiện nay như: VnExpress, Dân trí, VietNamNet, Tuổi Trẻ và Thanh Niên. Dữ liệu thu thập được làm sạch, xử lý và tiến hành phân tích mô hình cấu trúc PLS-SEM bằng công cụ SmartPLS. Kết quả nghiên cứu đã cung cấp một cơ sở thực chứng về tác động tích cực của các nhân tố ảnh hưởng đến sự trung thành thương hiệu và vai trò trung gian của sự hài lòng thương hiệu trong bối cảnh thương hiệu báo điện tử ở Việt Nam, từ đó đóng góp vào cơ sở lý thuyết về mô hình tài sản thương hiệu

Stimulation of shoot regeneration through leaf thin cell layer culture of Passiflora edulis Sims.

Passiflora edulis Sims. belonged to the genus Passiflora, is one of the important economic crops of the world as well as Vietnam. Nowadays, the commercial P. edulis is mainly propagated by seeds, cuttings and grafting; however, these methods still have some limitations such as genetic degradation and heterogeneity and the spread of pathogenic viruses. Micro-propagation has been used for clonal breeding and disease-free plant breeding, as well as providing a source of materials for Passiflora breeding. In this study, leaf explants of P. edulis Sims. (2.0-month-old) excised from the in vitro culture of ex vitro axillary buds cut longitudinally and transversally into thin cell layers (lTCL and tTCL) were used as plant materials to evaluate the shoot regeneration. In addition, the effects of explant age and lighting condition on shoot regeneration were also investigated. After 8 weeks of culture, the results showed that shoot regeneration rate (100%) and shoot multiplication coefficient (13.33) of the in vitro leaf-tTCL-4 were higher than those of other treatments and control. The shoot regeneration rate of P. edulis Sims. also varied with the change of explant age. The highest shoot regeneration rate (100%) was obtained from leaf explants of 1.5-month-old shoots after 8 weeks of culture. Moreover, the light (fluorescent lamps with photoperiod of 16 hours/day and lighting intensity of 40 - 45 μmol.m-2.s-1) improved not only morphogenesis rate, but also shoot regeneration rate (100%) of leaf explants after 8 weeks of culture. This study provided a novel method for rapid micro-propagation of P. edulis Sims

TỐI ƯU HÓA ĐIỀU KIỆN NUÔI CẤY VÀ KHẢO SÁT KHẢ NĂNG PHÂN HỦY DIBENZOFURAN VÀ NAPHTHALENE CỦA CHỦNG VI KHUẨN Paenibacillus naphthalenovorans 4B1

The pollution of polycyclic aromatic hydrocarbon compounds caused by herbicide residues contaminated with dioxin from the war and other wastes from industrial activities has left severe consequences to human health and the environment. Bioremediation using microorganisms capable of decomposing pollutant compounds exhibits more advantages than physicochemical treatment methods as it is highly efficient, economically feasible, sustainable, and eco-friendly. In this study, Paenibacillus naphthalenovorans strain 4B1, isolated from dioxin-contaminated soil in Vietnam, was optimized the culture conditions and evaluated its abilities to degrade dibenzofuran and naphthalene. The results revealed that strain 4B1 showed the best growth on mineral salts medium supplemented with dibenzofuran 1250 mg/L or naphthalene 750 mg/L, pH 7.0, incubated at 45°C and 180 rpm with a cell density of 9,42 × 107 và 5,6 × 107 CFU/mL, respectively. Gas chromatography analysis of the substrate concentrations indicated that strain 4B1 could degrade 79.76% of 1250 mg/L dibenzofuran and 83.03% of 750 mg/L naphthalene after 72 hours of incubation at optimal conditions. These results make Paenibacillus naphthalenovorans 4B1 a potential candidate for application in bioremediation of environments contaminated with polycyclic aromatic hydrocarbon compounds.Ô nhiễm các hợp chất hydrocarbon thơm đa vòng gây ra do dư lượng chất độc chiến tranh hoặc từ chất thải của các hoạt động công nghiệp đã để lại nhiều hậu quả nghiêm trọng cho sức khỏe con người và môi trường sinh thái. Phương pháp phục hồi sinh học sử dụng các vi sinh vật có khả năng phân hủy các hợp chất ô nhiễm cho thấy hiệu quả xử lý cao, chi phí thấp, bền vững và thân thiện với môi trường hơn so với các phương pháp lý hóa thông thường. Trong nghiên cứu này, chủng vi khuẩn Paenibacillus naphthalenovorans 4B1, phân lập từ đất nhiễm dioxin, được nghiên cứu tối ưu hóa các điều kiện nuôi cấy và đánh giá khả năng phân hủy các hợp chất dibenzofuran và naphthalene. Kết quả nghiên cứu cho thấy chủng vi khuẩn này sinh trưởng tốt nhất trên môi trường muối khoáng bổ sung 1250 mg/L dibenzofuran hoặc 750 mg/L naphthalene, pH 7,0, nuôi cấy ở nhiệt độ 45°C và tốc độ khuấy trộn 180 vòng/phút với mật độ tế bào lần lượt là 9,42 × 107 và 5,6 × 107 CFU/mL. Phân tích sắc ký khí hàm lượng cơ chất còn lại trong môi trường nuôi cấy cho thấy chủng 4B1 có khả năng phân hủy dibenzofuran và naphthalene với hiệu suất lần lượt là 79,76% và 83,03% sau 72 giờ nuôi cấy. Kết quả này là cơ sở cho việc ứng dụng chủng vi khuẩn Paenibacillus naphthalenovorans 4B1 trong nghiên cứu xử lý các môi trường bị ô nhiễm các hợp chất hydrocarbon thơm đa vòng

Feasibility of mango by-products and biogas solid residue aerobic co-composting at different C/N ratios

Purpose: Co-composting of mango by-products and biogas solid residue eliminates some shortcomings of composting these wastes separately. Specifically, co-composing solves the problem of the low pH values in mango by-products while enhances biodegradable organic matter of biogas solid residues. However, no research report is available on co-composting of mango by-products (MB) and biogas solid residue (BR). Method: This study established three in-vessel lab-scale composting bins with 3 different C/N ratios, including Bin 1: 27.4/1 (156 kg MB + 144 kg BR); Bin 2: 30.23/1 (193 kg MB + 107 kg BR); and Bin 3: 37.7/1 (224 kg MB + 76 kg BR). The raw compost materials underwent 57 days of incubation, including 36 days of raw incubation and 21 days of mineralization. Results: Bin 3 containing larger amounts of mango by-products and less amounts of biogas residue showed a higher percentage of remaining carbon in the final products (17.97%), lower nitrogen loss (17%), and showed 0.5% increase in available P2O5 content, compared to the other bins. From 300 kg of initial raw material, the final compost mass in Bin 1, Bin 2, and Bin 3 were 26.2 kg, 32.7 kg, and 88.1 kg, respectively. Conclusion: Resultantly, an initial C/N ratio of 37.7/1 could be suggested in the aerobic co-composting of biogas residue with mango by-products. Research Highlights ·       Co-composting of mango by-products and biogas solid residue eliminates some of the weaknesses of composting these wastes separately. ·       The incubation period determined was 57 days of incubation, including 36 days of raw incubation and 21 days of mineralization. ·       Among three C/N ratios surveyed, the highest C/N in bin 3 (C/N=37.7/1) showed the best-favoured condition for mango by-products treatment and generate the highest amount of compost product. ·       Bin 3 showed the highest percentage of remaining carbon in compost products (17.97%), a lower in nitrogen loss (17%), and 0.5% increase in available P2O5 content