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

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 essential oils from Homalomena pierreana (Araceae)

30-37Homalomena is a genus of the Araceae family which contains several remedies used extensively in traditional Vietnamese medicine. H. pierreana is a rare plant species of Homalomena genus and found only in Phu Quoc National Park, Phu Quoc Island, Kien Giang Province, Vietnam. Therefore, the number of studies about this species is limited and the bioactivity of this species is still unknown. In this study, the chemical composition of essential oils was investigated which was isolated from leaves and rhizomes of H. pierreana at the first time by GC-MS. Eight and twelve compounds were identified from the essential oils of rhizomes and leaves, respectively. The major component from both the rhizomes and the leaves was aromadendrene (44 and 48%, respectively). Furthermore, the antibacterial activity of essential oils collected from leaves and rhizomes of H. pierreana was investigated and it was observed that the essential oil of rhizomes could inhibit the growth of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, while the essential oil of leaves exhibited an inhibitory effect against Staphylococcus aureus and Escherichia coli.</em

Research on chemical constituents, anti-bacterial and anti-cancer effects of components isolated from Zingiber officinale Roscoe from Vietnam

Ginger, a commonly used spice and medicinal herb, is an abundant source of bioactive compounds. However, the utilization of ginger in the pharmaceutical industry is still moderate and not commensurate with the potential of the Vietnamese horticulture industry, mainly due to a lack of information about the quality of input materials. In this study, we compared the volatile compounds of gingers collected from 13 provinces of Vietnam using GC/MS and GC-FID analysis to provide a basis for selecting and standardizing input materials. Furthermore, ginger essential oil from Ben Tre province of Vietnam exhibited significant antibacterial activity particularly in inhibiting Gram-positive bacteria, including S. aureus and S. epidermidis, with inhibition zones of 30.00 ± 1.41 and 24.67 ± 3.30 mm, respectively. However, no significant inhibition was observed against Gram-negative bacteria P. aeruginosa and E. coli. We also isolated 5 non-volatile compounds from ginger extract, namely 6-shogaol (1), quercetin (2), rutin (3), beta-sitosterol (4) and beta-sitosterol-3-O-beta-D-glucopyranoside (5). Among them, compounds 1–3 displayed cytotoxicity against Hep3B, SK-LU-1, MCF-7, SK-LU-1, SW480 and HepG2 tumour cell lines, with an IC50 values ranging between 62.7 ± 2.1 and 97.6 ± 1.1 µM, using Ellipticine as a positive control. Compounds 4 and 5 showed cytotoxicity against Hep3B and HepG2 tumor cells, with the IC50 values ranging between 21.5 ± 5.1 and 46.9 ± 3.7 µM but did not exhibit any significant cytotoxicity against SW480 and SK-LU-1 cells. Compound 4 also demonstrated middling cytotoxicity against the MCF7 cell line, with an IC50 value of 43.6 ± 5.1 µM. These findings suggest further applications of Vietnamese ginger for the treatment of infectious and cancer-related diseases

BACTERICIDAL ACTIVITY OF NANOSILVER AGAINST PATHOGENIC MICROORGANISMS WHICH CAUSE PECULAR DISEASES OF GENITAL SECRETION TRACK

      Nano silver was known as a bactericidal agent for almost all bacterial species and has been intensively investigated over the world to apply for disinfection in different fields of human activities and environmental protection. Specifically, genital exudate media contain numerous dangerous bacteria such as Neisseria gonorrhoeae, Enterococcus faecalis, Staphylococcus aureus, Candida albicans etc. which as a rule are drug-resistant with respect to antibiotics. This research presents the results of the application of nanosilver in replacing antibiotics in elimination of the above mentioned microorganisms by using low nanosilver concentrations of about 0.01 mg/cm2 immobilized on non-woven fabric. The experimental data showed that nanosilver-impregnated fabric samples at a concentration 0.01 mg/cm2 gave antibacterial rings of 10 mm, 9 mm and 8 mm, respectively, for        N. gonorrhoeae, Candida albicans + E.coli and Candida albicans + E.coli + S. aureus

Chemical Components of Essential Oils From the Leaves of Seven Species Belonging to Rutaceae Family from Binh Chau-Phuoc Buu Nature Reserve, Vietnam

Several plant species of the Rutaceae family are medicinal plants, oil bearing and food crops. To provide more information for utilization of some species of this family in Binh Chau-Phuoc Buu Nature Reserve, we extracted essential oils from the leaves of seven species of the Rutaceae family: Acronychia pedunculata (L.) Miq., Atalantia citroides Pierre ex Guillaumin, Clausena excavata Burm.f., Glycosmis pentaphylla (Retz.) DC., Luvunga scandens (Roxb.) Buch.-Ham. ex Wight & Arn, Melicope pteleifolia (Champ. ex Benth.) T.G. Hartley, and Micromelum sp., via hydrodistillation, and identified their components using GC/MS analysis. A total of 60 compounds were identified from essential oils of seven species. The main components of the essential oils isolated from five species, including A. pedunculata, C. excavata, M. pteleifolia, G. pentaphylla, and Micromelum sp., were caryophyllene (57.63% and 55.41% in A. pedunculata and C. excavata, respectively), 1,9-decadiyne (32.59%, M. pteleifolia), β-ocimene (23.10%, G. pentaphylla), and 3-carene (58.03%, Micromelum sp.). Additionally, this study revealed the chemical composition of essential oils of L. scandens and A. citroides for the first time. The main constituent of A. citroides was 7-oxabicyclo[4.1.0] heptane, 3-oxiranyl- (53.91%) and that of L. scandens was caryophyllene (34.66%). These findings provide the basis for further application of these species in medicine

Chemical composition and antibacterial activities of essential oils from Homalomena pierreana (Araceae)

Homalomena is a genus of the Araceae family which contains several remedies used extensively in traditional Vietnamese medicine. H. pierreana is a rare plant species of Homalomena genus and found only in Phu Quoc National Park, Phu Quoc Island, Kien Giang Province, Vietnam. Therefore, the number of studies about this species is limited and the bioactivity of this species is still unknown. In this study, the chemical composition of essential oils was investigated which was isolated from leaves and rhizomes of H. pierreana at the first time by GC-MS. Eight and twelve compounds were identified from the essential oils of rhizomes and leaves, respectively. The major component from both the rhizomes and the leaves was aromadendrene (44 and 48%, respectively). Furthermore, the antibacterial activity of essential oils collected from leaves and rhizomes of H. pierreana was investigated and it was observed that the essential oil of rhizomes could inhibit the growth of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, while the essential oil of leaves exhibited an inhibitory effect against Staphylococcus aureus and Escherichia coli

HIV and Tuberculosis in Ho Chi Minh City, Vietnam, 1997–2002

An emerging HIV epidemic, concentrated in young, male, injection drug users, is responsible for increasing TB reporting rates in urban Vietnam