The spread of artemisinin-resistant Plasmodium falciparum compromises the therapeutic efficacy of artemisinin combination therapies (ACTs) and is considered the greatest threat to current global initiatives to control and eliminate malaria. This is particularly relevant in Vietnam, where dihydroartemisinin-piperaquine (DP) is the recommended ACT for P. falciparum infection. The propeller domain gene of K13, a molecular marker of artemisinin resistance, was successfully sequenced in 1,060 P. falciparum isolates collected at 3 malaria hot spots in Vietnam between 2009 and 2016. Eight K13 propeller mutations (Thr474Ile, Tyr493His, Arg539Thr, Ile543Thr, Pro553Leu, Val568Gly, Pro574Leu, and Cys580Tyr), including several that have been validated to be artemisinin resistance markers, were found. The prevalences of K13 mutations were 29% (222/767), 6% (11/188), and 43% (45/105) in the Binh Phuoc, Ninh Thuan, and Gia Lai Provinces of Vietnam, respectively. Cys580Tyr became the dominant genotype in recent years, with 79.1% (34/43) of isolates in Binh Phuoc Province and 63% (17/27) of isolates in Gia Lai Province carrying this mutation. K13 mutations were associated with reduced ring-stage susceptibility to dihydroartemisinin (DHA) in vitro and prolonged parasite clearance in vivo. An analysis of haplotypes flanking K13 suggested the presence of multiple strains with the Cys580Tyr mutation rather than a single strain expanding across the three sites.

In this study, CdSe quantum dots (QDs) were prepared using colloidal trioctylphosphine (TOP) with an organic ligand layer and oleic acid as a capping agent, and a photoelectrode anode was prepared using CdS/CdSe QDs/ZnS thin film deposition on a TiO2 electrode via the successive ionic layer adsorption and reaction (SILAR) method. The results indicated that the short current density increased from 4.79 mA/cm2 to 13.97 mA/cm2 because the conduction band of the CdSe (size ∼ 3 nm) QDs became higher than that of both TiO2 and CdS. As a result, the stimulated electrons were efficiently injected into the conduction band of TiO2 and CdS. In addition, the dynamic resistance and the lifetime of stimulated electrons in the QDSSCs were investigated using Nyquist and Bode plots. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1774–1779, 2015

Kết quả cho thấy những lô thí nghệm có bổ sung Astaxanthin làm tăng màu sắc da của cá so với lô đối chứng (P<0,05) nhưng không có sự khác biệt có ý nghĩa về tăng trưởng và tỷ lệ sống giữa các lô thí nghiệm với nhau (P > 0,05).

Learner autonomy is deemed as one of the long-term goals in English language teaching and learning in the 21st century; nevertheless, that students are ready for learner autonomy varies from one context to another. Furthermore, learner autonomy is variously perceived in different contexts. This research aims to explore non-English majors’ readiness for learner autonomy concerning self-awareness, self-efficacy, and motivation in a college in Ho Chi Minh City, Vietnam. The quantitative approach was employed for data collection. A cohort of 134 students was involved in partaking in answering a closed-ended questionnaire. The collected data were statistically analyzed in terms of mean and standard deviation. The results unraveled that the participants were highly ready for learner autonomy. They were aware of learner autonomy and had high self-efficacy and motivation for their own English learning. The preliminary findings are expected to bring theoretical and practical contributions to students’ readiness for learner autonomy in this research context and other similar ones.

Polyvinyl alcohol (PVA) is well-known in the packaging industry, especially in the food and medical fields with the ability to be completely biodegradable and easily soluble in cold water therefore products made from it are the environmentally friendly materials. However, the disadvantages of this polymer as quick dissolubility in water, poor moisture retention, weak mechanical properties reduce its applications. In this study, PVA, reinforced by “green” components at the nanometer-level such as nanocellulose fibers (CNF), graphene oxide (GO) nanosheets showed improvements in properties. Mechanical properties of all of nanocomposite films showed improvements in stress at break and modulus. Especially, reinforced GO and CNF films increased almost doubled and improved more 40% in modulus than the pure PVA film and films reinforced by only GO or CNF. When immersed in water (neutral pH) at room temperature, graphene oxide-reinforced films not only had effective improvements in swelling time but also supported to decrease water retension of film added CNF. The combined reinforcement also indicated a benefit in reducing the rate of water vapor loss of the film as well as the efficiency in declining the moisture absorption of the nanocomposite films. The PVA films reinforced by nanocellulose fibers and graphene oxide sheets overcomed some of the PVA's shortcomings. This helped expanding its applications in the field of environmentally friendly nanocomposite films.

In this study, graphene oxide (GO) is synthesized by a modified Hummers method, Polyvinyl alcohol (PVA) films and PVA/ GO nanocomposite films are prepared by casting stable aqueous mixed solutions. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) showed that there were a good compatibility and dispersion of graphene oxide (GO) on PVA matrix. In addition, nanocomposite films reinforced graphene oxide with the content of only 0.6 % phr have had 10.11% higher tensile strength, 12.24 % greater Young modulus, and significantly reduced water permeability during 4 hours of continuous immersion. Nanocomposite films maintained good thermal stability despite being added with graphene oxide, a material that is considered to have low thermal stability that easily decomposes below 200 oC, so thermal gravimetric analysis diagram (TGA) of PVA/ GO almost did not show a change compared to the neat PVA film. Initial results show that the efficiency of dispersing and reinforcing graphene oxide material on PVA resins has ameliorated the drawbacks of this polymer and contributed to extending the application of PVA in many areas. This has also reached closer to the goal of cleaning the environment by replacing non-biodegradable polymer sources with more friendly polymers.