TEACHERS’ PERCEPTIONS OF SCAFFOLDING EFL STUDENTS’ READING COMPREHENSION AT HIGH SCHOOLS IN THE MEKONG DELTA, VIETNAM

Scaffolding has held great appeal for teachers of English as a foreign language (EFL) and scholars in helping students take greater responsibility or ownership in their language learning and reach academic success. However, little is known about how teachers perceived this type of support as improving students’ reading comprehension in English within the teaching and learning context in Vietnam high schools. This paper therefore reports a descriptive study that explored teachers’ perceptions of scaffolding EFL students’ reading comprehension at high schools in the Mekong Delta, Vietnam. Questionnaires and semi-structured interviews were employed to collect data from seventy-nine high school teachers. The findings provide insightful views into teachers’ perceptions about scaffolding students’ reading comprehension. The findings also reveal how teachers experienced varying degrees of their perceptions of scaffolding and challenges while delivering their scaffolding practices in reading instruction. Article visualizations

EDMODO USE IN ESP WRITING: STUDENTS’ PERCEPTIONS

A growing body of literature has examined the nature of blended learning and its effects on language teaching and learning, including the use of Edmodo to promote student writing. However, this type of integration of face-to-face instruction and online learning remains relatively new for EFL contexts. Also, teaching writing at the Vietnamese contexts, particularly in the ESP tertiary education, is still largely dependent on conventional way. This paper therefore reports students’ perceptions about Edmodo use in writing classes at a Vietnamese university. This paper draws on data collected as part of a larger mixed methods project including tests and interviews over a fifteen-week semester of an ESP writing class. In this paper, the focus is the data from interviews, which explored how students perceived the effects of Edmodo use in their writing learning process. The findings indicate students’ positive perceptions about this supportive learning delivery method in writing classes. Implications for teachers and school administrators with regard to practical applications of Edmodo as a potential tool are also discussed.  Article visualizations

TEACHER CORRECTIVE FEEDBACK ON STUDENTS’ SPEAKING PERFORMANCE AND THEIR UPTAKE IN EFL CLASSES

Corrective feedback plays a critical role in language teaching and learning, but little research has been done with regard to teachers’ practices of corrective feedback on students’ speaking performance and their uptake. This paper therefore reports on a descriptive study using qualitative approach to provide insights into strategies teachers used to deliver corrective feedback to their students’ speaking performance and distribution of student uptake within EFL context. Data were collected from observations of two teachers and fifty students at a private high school in a Mekong Delta region. The findings indicate that recast and explicit correction were used the most and that clarification request, recast, and metalinguistic cue were effective in helping students recognize their errors. Implications for language teaching are also presented

Chemical diversity of the Melaleuca cajuputi leaf oils from six locations in southern Vietnam

Melaleuca cajuputi Powell, a member of Myrtaceae family, is a popular and valuable plant in Vietnam, especially in the southern region. In this study, gas chromatography-mass spectrometry was used to determine the diversity in chemical composition of M. cajuputi leaf oil collected from six sites in the South of Vietnam. A total of sixty compounds has been identified from the essential oils of M. cajuputi leaf, such as α-thujene, α-pinene, benzaldehyde, β-pinene, β-myrcene, α-phellandrene, α-terpinene, benzene, 1-methyl-2-(1- methylethyl), 1,8-cineole, γ-terpinene, etc. Among those, five compounds were found in all six samples including α-thujene, α-pinene, α-phellandrene, γ-terpinene, and α-terpinolene, whereas other compounds were only present in some samples with varying amounts. Principal Component Analysis (PCA) has been performed to examine the similarities in the composition of leaf oils among the collection sites using XLSTAT software. The results from PCA suggested that six samples of leaf oil could be classified into 2 chemotypes with different chemical constituents. Note that 1,8-cineole only occurred in chemotype group 1 whereas it was omitted in chemotype group 2. This finding explains the diversity of bioactivity of M. cajuputi collected from different regions and provide more information on M. cajuputi for further application in medicine and food industry

Synthesis and structural characteristics of platinum(II) complexes with N(4)-substituted thiosemicarbazones

Three ligands, namely 4-nitrobenzaldehyde-[N(4)-methyl, N(4)-phenyl thiosemicarbazone] (HL1), fluoren-9-one-[N(4)-(4-methylpiperidinyl)thiosemicarbazone] (HL2), and 4’-hydroxyacetophenone-[N(4)-(4-methylpiperidinyl)thiosemicarbazone] (HL3) as well as three corresponding Pt(II) complexes ([Pt(Li)2](i = 1;2;3)), were synthesized and fully characterized. The analysis of IR, UV-vis, MS, 1H-NMR, 13C-NMR, COSY, and HSQC illustrated that HL1, HL2, HL3 were bidentate ligands and bound to the metal through the imine nitrogen and the net negatively charged sulfur in thiol form. Furthermore, it was demonstrated that the chelating ligands in the Pt(II) complexes were in the trans configuration. Keywords. Thiosemicarbazone, platinum(II) complexes, coordination compounds, inorganic synthesis

Measurement of Protein Mobility in Listeria monocytogenes Reveals a Unique Tolerance to Osmotic Stress and Temperature Dependence of Diffusion

Protein mobility in the cytoplasm is essential for cellular functions, and slow diffusion may limit the rates of biochemical reactions in the living cell. Here, we determined the apparent lateral diffusion coefficient (DL) of GFP in Listeria monocytogenes as a function of osmotic stress, temperature, and media composition. We find that DL is much less affected by hyperosmotic stress in L. monocytogenes than under similar conditions in Lactococcus lactis and Escherichia coli. We find a temperature optimum for protein diffusion in L. monocytogenes at 30°C, which deviates from predicted trends from the generalized Stokes-Einstein equation under dilute conditions and suggests that the structure of the cytoplasm and macromolecular crowding vary as a function of temperature. The turgor pressure of L. monocytogenes is comparable to other Gram-positive bacteria like Bacillus subtilis and L. lactis but higher in a knockout strain lacking the stress-inducible sigma factor SigB. We discuss these findings in the context of how L. monocytogenes survives during environmental transmission and interaction with the human host.</p

Chemical Constituents and Bacterial Activity of Essential Oils of Five Wax Apples (Syzygium samarangense) from Dong Thap Province, Vietnam

In the present study, essential oils from the leaves of five varieties of wax apple trees, (\u27An Phuoc\u27, \u27Hoa An\u27, \u27Hong Dao\u27, \u27Sua\u27, and \u27Xanh Duong\u27) collected in Dong Thap Province, Vietnam were isolated using hydrodistillation, and their constituents were for the first time identified via gas chromatography - mass spectrometry. A total of 74 compounds from essential oils were identified. These compounds were classified into four clusters by hierarchical clustering analysis. The main constituents of the essential oils isolated from the leaves of five varieties of wax apple trees were o-cymene, α-cubebene, epizonarene, β-gurjunene, and α-selinene. The antibacterial activity of the essential oils isolated from the leaves of five varieties of wax apples were evaluated for the first time. The results showed that the essential oils could inhibit the growth of four tested microorganisms: Bacillus cereus, Escherichia coli, Salmonella enteritidis and Staphylococcus aureus

Chemical Constituents and Bacterial Activity of Essential Oils of Five Wax Apples (Syzygium samarangense) from Dong Thap Province, Vietnam

In the present study, essential oils from the leaves of five varieties of wax apple trees, (\u27An Phuoc\u27, \u27Hoa An\u27, \u27Hong Dao\u27, \u27Sua\u27, and \u27Xanh Duong\u27) collected in Dong Thap Province, Vietnam were isolated using hydrodistillation, and their constituents were for the first time identified via gas chromatography - mass spectrometry. A total of 74 compounds from essential oils were identified. These compounds were classified into four clusters by hierarchical clustering analysis. The main constituents of the essential oils isolated from the leaves of five varieties of wax apple trees were o-cymene, α-cubebene, epizonarene, β-gurjunene, and α-selinene. The antibacterial activity of the essential oils isolated from the leaves of five varieties of wax apples were evaluated for the first time. The results showed that the essential oils could inhibit the growth of four tested microorganisms: Bacillus cereus, Escherichia coli, Salmonella enteritidis and Staphylococcus aureus

Chemical composition and antibacterial activities of the ethanol extracts from the leaves and tubers of Amorphophallus pusillus

Amorphophallus pusillus is a rare species which is found only in Binh Chau-Phuoc Buu Nature Reserve. In this study, we determined 7 flavonoid compounds in tuber and leaf of A. pusillus, including of vitexin, orientin, vitexin 2?-O-glucoside, cyanidin 3-O-rutinoside, pelargonidin 3-O-glucoside, schaftoside, and peonidin 3-O-rutinoside via liquid chromatography-mass spectrometry (LC-MS). Furthermore, we have proved the antibacterial activities of ethanol extracts obtained from A. pusillus leaves and tubers in the first time. The data revealed that ethanol extracts could inhibit the growth of 6 tested microorganisms, such as Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis, Salmonella typhimurium, and Staphylococcus aureus. These data suggested the potential application of ethanol extracts isolated from this species as natural antimicrobial agents for treatment of infection caused by bacteria, especially in dermatologic and enteric infections