Catalytic Activity of Cr2O3/sepiolite in the oxidation of benzyl alcohol

Cr2O3/sepiolite samples with different loadings have been prepared through the precipitation method and characterized by several physical methods such as XRD, TEM, BET, and TGA... The as-prepared materials have large surface area, high distribution of Cr2O3 nanoxides on the nanofibrous sepiolite. The catalysts have been tested in the oxidation of benzyl alcohol with t-BuOOH. Chromium oxides were found to be active sites for the oxidation of benzyl alcohol to aldehyde. The catalytic activity varied with reaction time and temperature. The appropriate temperature is about 60-70oC with conversion of 40-60% and benzaldehyde selectivity of 90%

Oxidation of benzyl alcohol to benzaldehyde over MnOx/sepiolite catalysts

MnOx/sepiolite catalysts were synthesized by precipitation method accompanied by the calcination at 4100C. The prepated solids have been characterized by XRD, SEM, TPR-H2. MnOx particles were deposited on the surface of the sepiolite fibers and act as active sites for  the oxidation of benzyl alcohol using tert-butyl hydroperoxide (TBHP) as an oxidizing agent. The catalysts showed a good conversion of benzyl alcohol to benzaldehyde at 60 oC. The influence of the reaction time and reaction temperature was considered. Keywords. MnOx/sepiolite, oxidation, benzyl alcohol conversion, TBHP, benzaldehyde

AN INVESTIGATION INTO THE COMMON ERRORS OF WORD FORM USED IN WRITING OF THE FRESHMEN: A CASE STUDY

English has been used all across the world, including in Vietnam. From middle school to high school and even university, Vietnamese students have numerous opportunities to engage with English grammar, but there is still a significant gap between their understanding and the correct application of English grammar. In fact, Grammar has a significant impact on the writing skills of Vietnamese students in general, and especially the first-year students of English majors who were not much exposed to writing in high school, so they are not yet used to writing at a higher level. The majority of errors in their writings are due to the influence of their mother tongue and a lack of frequent practice and their misuse of word forms, as a matter of fact, the expected results have not been satisfactory. Based on the general insight into the writing competence of the freshmen, the study titled “An investigation into the common errors of word forms made in the writings of the freshmen: A case study” was done with the English-major students. A close survey was deliberately done with 142 paragraphs written by the first-year students to investigate the common errors of word forms made in their writings. From what was collected, the study subsequently offered some suggestions for helping the students improve their writing skills.  Article visualizations

SURVEY ON VOCABULARY LEARNING STRATEGIES OF HIGH–QUALITY ENGLISH STUDIES PROGRAM STUDENTS, SCHOOL OF FOREIGN LANGUAGES, CAN THO UNIVERSITY, VIETNAM

This research study aimed to investigate the usage of vocabulary learning strategies among English Studies students at Can Tho University (CTU), specifically those under the high-quality program at the School of Foreign Languages (SFL). The primary objective of the study was to identify the most commonly used strategies for learning English vocabulary and to compare the similarities and differences in how these strategies were applied among students by academic year. A total of 200 survey responses from SFL, CTU got involved in the study, and 12 of whom joined a semi-structured interview. The data gathered were analyzed using both descriptive and inferential statistical techniques. The results of this study provided insights into effective vocabulary learning strategies and would facilitate the improvement of English language teaching and learning practices at the university level.  Article visualizations

Choosing the best machine tool in mechanical manufacturing

Machine tools are indispensable components and play an important role in mechanical manufacturing. The equipment of machine tools has a huge effect on the operational efficiency of businesses. Each machine tool type is described by many different criteria, such as cost, technological capabilities, accuracy, energy consumption, convenience in operation, safety for workers, working noise, etc. If the selection of machine is only based on one or several criteria, it will be really easy to make mistakes, which means it is not possible to choose the real best machine. A machine is considered to be the best only when it is chosen based on all of its criteria. This work is called multi-criteria decision-making (MCDM). In this study, the selection of machine tools has been done using two different multi-criteria decision-making methods, including the FUCA method (Faire Un Choix Adéquat) and the CURLI method (Collaborative Unbiased Rank List Intergration). These are two methods with very different characteristics. When using the FUCA method, it is necessary to normalize the data and determine the weights for the criteria. Meanwhile, if using the CURLI method, these two things are not necessary. The selection of these two distinct methods is intended to produce the most generalizable conclusions. Three types of machine tool, which are considered in this study, include grinding machine, drilling machine and milling machine. The number of grinders that were offered for selection was twelve, the number of drills that were surveyed in this study was thirteen, while nine were the number of milling machines that were given for selection. The objective of this study is to determine the best solution in each type of machine. The results of ranking the machines are very similar when using the two mentioned methods. Specially, in all the surveyed cases, the two methods FUCA and CURLI always find the same best alternative. Accordingly, it is possible to firmly come to a conclusion that the FUCA method and the CURLI method are equally effective in machine tool selection. In addition, this study has determined the best three machines corresponding to the three different machine type

Extract and fraction of cashew nut testa ameliorate the hyperglycemic mice induced by Streptozotocin and high-fat diet

Drug strategy is a standard method for treating type 2 diabetes mellitus (T2D), a non-communicable disease with increasing prevalence, which may cause side effects. Therefore, natural compounds with limited adverse effects have come back into vogue for treating T2D. This study aims to evaluate the effects on rehabilitating hyperglycemic mice of cashew nut testa (husk) extract and fraction known as potential bio-substances for improvement in T2D. First, the hyperglycemic mice were induced with a high-fat diet (HFD) for 4 weeks and then were injected with streptozotocin (STZ, dozen for injection was 40 mg/kg/week) for 2 weeks. Next, the confirmed hyperglycemic mice were treated with pioglitazone (HG+PG group), total extract (HG+TE group), and saponin-rich fraction (HG+SRF group) for 3 weeks. Then, the evaluation was based on body mass; blood glucose (BG) level; BG tolerance, lipid profile, pancreatic histology and the expression IRS-1 in the pancreas. The results showed that body mass and BG level significantly increased in hyperglycemic mice. After substance treatment, there was no change in body mass in TE and SRF groups. However, BG level of HG+TE group mice significantly decreased compared to hyperglycemic mice and only BG tolerance of HG+SRF group was improved. Besides, HG+TE and HG+SRF groups modulated the triglyceride, HDL and LDL close to those expressed in normal mice. In addition, histological images of the pancreas revealed the restoration in both HG+TE and HG+SRF groups. Simultaneously, the IRS-1 expression in HG+TE group pancreas was restored to its expression in normal mice. These results demonstrate that the TE and SRF of cashew nut testa could ameliorate BG, lipid profile and pancreatic IRS-1 expression and restore the damaged pancreas and islets in hyperglycemic mice

Synthesis and application of Fe3O4/GO/PVP composite material for methylene blue adsorption

In this study, Fe3O4/GO/PVP (FGP) was successfully synthesized and efficiently applied for absorbing methylene blue. First, GO was synthesized by Hummer’s method from waste home-batteries. The chemical co-precipitation method was used to fabricate Fe3O4/GO from a mixture solution of GO, Fe3+, Fe2+. Polyvinylpyrrolidone PVP was selected to functionalize Fe3O4/GO and form Fe3O4/GO/PVP for improving dispersibility purpose in aqueous solution. The obtained Fe3O4/GO/PVP was characterized by XRD, FT-IR, BET, FE-SEM, UV-Vis techniques. Moreover, the effecting factors as pH, time adsorption, initial concentration of methylene blue were conducted. Adsorption isotherm models were also identified. The results showed that specific surface area of FGP-3 was 70.0 m2.g-1, the Freundlich isotherm model was suitable and the Dubinin - Radushkevich isotherm model showed that the process was physical adsorption. The maximum capacity (qmax) was 30.4 mg.g-1. These findings prove Fe3O4/GO/PVP as an inexpensive and efficient adsorbent for removal of cationic dyes

LEARNING IDIOMS FOR ENGLISH MAJORS: VIETNAMESE STUDENTS’ PERCEPTIONS OF DIFFICULTIES AND LEARNING STRATEGIES

Learning idioms play an influential role in language generally and in English notably. Comprehending idioms assists language learners in integrating culture, enhancing skills, and ameliorating English levels. Numerous studies have analyzed the function of idioms in second language acquisition (Cieślicka, 2015). This study investigates the difficulties and strategies used in learning idioms by English-majored students at a regional public university (PU) in the south of Vietnam. This paper furnishes data showing learners’ perceptions of facing complications and learning methods. The samples consisted of 150 undergraduate EFL students from English-medium instruction programs. The data was analyzed by utilizing descriptive and inferential statistics. The findings reveal that students struggle to understand idiomatic terms without specific, understandable contexts. Furthermore, the results indicate that the most frequently employed strategies are guessing the meaning of idioms, learning idioms through keywords, and learning from a range of sources, particularly via media. The findings also mentioned that low-proficiency and high-proficiency students encounter identical challenges, with no significant differences. The study's results revealed that the majority of students have difficulty acquiring, recognizing, and interpreting idioms. The findings indicated that guessing the implication of idioms is the most used strategy.  Article visualizations

Development of blood transfusion external quality assessment program at national scale

Introduction: External quality assessment is a crucial component in ensuring the quality of blood transfusion testing laboratories. Objectives: To develop a procedure for generating external quality assessment items for blood transfusion testing to evaluate participants' performance. Methods: Experimental research was conducted at Quality Control Center for Medical laboratory- University of Medicine and Pharmacy at Ho Chi Minh City, Vietnam. Three items, including red blood cell, serum, and atypical antibody serum samples, were assessed for homogeneity and stability; 5 assessment areas, including ABO grouping, Rh grouping, compatible cross matches, Coombs test, and screening of atypical antibodies, were utilized to evaluate the performance of 38 participants in the 2020-2021 period. Results: Red blood cell and serum samples maintained quality for a specific period at controlled temperatures, while serum samples with atypical antibodies showed stability at different temperatures. The participants demonstrated high satisfactory performance in ABO grouping, Rh grouping, Coombs test, and screening for atypical antibodies. However, the most unsatisfactory performance was reported in crossmatching, with 15% of participants unsatisfactory results. Conclusion: The procedure of production of proficiency testing items has been successfully developed, and its application at the national level is suggested to improve the quality of blood transfusion laboratories

A multi-scale epidemic model of Salmonella infection with heterogeneous shedding∗

Salmonella strains colonize the digestive tract of farm livestock, such as chickens or pigs, without affecting them, and potentially infect food products, representing a threat for human health ranging from food poisoning to typhoid fever. It has been shown that the ability to excrete the pathogen in the environment and contaminate other animals is variable. This heterogeneity in pathogen carriage and shedding results from interactions between the host’s immune response, the pathogen and the commensal intestinal microbiota. In this paper we propose a novel generic multiscale modeling framework of heterogeneous pathogen transmission in an animal population. At the intra-host level, the model describes the interaction between the commensal microbiota, the pathogen and the inflammatory response. Random fluctuations in the ecological dynamics of the individual microbiota and transmission at between-host scale are added to obtain a drift-diffusion PDE model of the pathogen distribution at the population level. The model is further extended to represent transmission between several populations. The asymptotic behavior as well as the impact of control strategies including cleaning and antimicrobial administration are investigated through numerical simulation