Search

Titanium oxides nanotubes (TNTs) were prepared by hydrothermal method and used as nano-support for nickel nanoparticles. Indeed, nickel nanoparticles supported TNTs (Ni-TNTs) were in situ synthesized from nickel salt and TNTs by chemical reduction method using sodium borohydride (NaBH4) as reducing agent. The physio-chemical properties of Ni-TNTs nano-catalysts were fully characterized such as Transmission Electron Microscopy (TEM), Scanning Electron Microscope (SEM), and X-ray diffraction (XRD). The results showed that nickel salt was completely reduced to Ni0 metal with an average particle size of 12 nm. On the other hand, the catalytic activity is tested by the hydrodechlorination of chlorinated organic compounds. The hydrode-chlorinated conversion of 3-chlorophenol was obtained over 97%.

This study is to investigate the capability of producing lignin-based phenol-formaldehyde adhesive (LBPFA) with lignin derived from coir pith collected in the Mekong Delta, Viet Nam. The LBPFA synthetic process underwent non chemical modifications to minimize petrochemicals and energy. Effective factors as reaction time, reaction temperature and various lignin contents of phenol substitution were examined. Physical, chemical and thermal properties containing formaldehyde content, viscosity, solid content, Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), tensile strength, tensile modulus and tensile strain were conducted. LBPFA was successfully synthesized at various levels of lignin contents substituting for phenol. The LBPFA’s parameters were in accordance with GB/T14372-2006 standard. The optimum reaction time, reaction temperature and lignin replacement content for LBPFA synthesis process were identified at 180 minutes, 900C and 40% wt/wt, respectively. The LBPFA showed the highest dry and wet tensile strengths of 14.42 MPa and 7.66 MPa on wooden boards compared to corresponding figures of commercial resin with 2.98 MPa and 0 MPa, respectively. For plywood, bending strength shown in LBPFA and commercial adhesive were 15.97 MPa and 20.16 MPa, respectively.

Copy number variation (CNV) analysis is a powerful tool for discovering structural genomic variation. Still, no program uses this tool to analyze chromosomal aneuploidies in the Vietnamese population. Pregnant women attending routine prenatal checkups in Vietnam from October 2018 to May 2021 were included in this study and contributed fetal tissue to test the utility of CNV analysis for prenatal screening. Among 5,008 women screened, 958 (19.13%) harbored at least one CNV, comprising segmental aneuploidy (8.49%), trisomy (6.91%), multiple anomalies (2.10%), and sex chromosome abnormality (1.64%). The rate of segmental aneuploidy detection increased with gestational age, but trisomy and sex chromosomal abnormalities detection decreased as the pregnancy continued. This study also found an association between abnormal CNVs and several phenotypic markers. For ultrasound soft markers, an increased nuchal fold thickness correlated with a higher risk of abnormal CNVs. In addition, many soft indicators or structural abnormalities were significantly associated with an increased likelihood of abnormal CNVs. This work highlights the importance of CNV analysis for the early detection of prenatal congenital abnormalities, especially in the first trimester. This study’s findings will meaningfully aid policymakers in developing cost-effective genetic prenatal screening programs.

It could be broadly accepted that oral presentations are becoming important for students. It is required in almost every field and in the university environment. To succeed in the university environment and in their future jobs, these students need to improve their oral presentation skills. However, one of the drawbacks of using oral presentations in the language classroom is that students often find oral presentations extremely challenging. Therefore, the researcher conducted this research with the main goal of finding out common problems when giving an oral presentation to English-majored juniors at Tay Do University. Ninety juniors majoring in English at Tay Do University were selected to take part in the study. Data are gathered through questionnaires and interviews. The researcher used quantitative and qualitative methods to do the research. From the collected data, when they give a presentation, students usually make some mistakes such as problems in vocabulary, grammar, pronunciation, psychological and background knowledge. Through this study, they would recognize their own problems when giving a presentation. Besides, understanding students' learning difficulties may also enable teachers to help students develop effective learning strategies and ultimately improve their presentation skills. It is hoped that this research can be helpful for not only students but also teachers in learning and teaching English. Article visualizations

In this study, we characterized the first clinical Klebsiella pneumoniae strain co- harboring mcr-1 and blaNDM-4 genes in Vietnam, which was recovered from a patient admitted to hospital in 2015. This strain demonstrated nonsusceptible to all tested antibiotics, including last-line antibiotics such as carbapenems (MICs ≥128 μg/mL) and colistin (MIC =32 μg/mL), except tigecycline (MIC =1 μg/mL). Whole-genome analysis using both MinION and MiSeq data revealed that the strain carried 29 resistance genes. Particularly, mcr-1 and blaNDM-4 genes were carried by different self-conjugative plasmids and able to be transferred to a recipient by conjugation. The colistin resistance of this strain was conferred by mcr-1 and additional chromosomal resistance determinants. Eight amino acid substitutions found in PmrA, PmrB, PmrC, PmrI, and PmrJ, all proteins that are involved in lipopolysaccharide modifications, may be associated with chromosomal colistin resistance. The accumulation of multiple antibiotic resistance mechanisms in this clinical isolate raises alarm on potential spread of extensively drug-resistant K. pneumoniae in healthcare settings.

Raw foods such as fish and meat sold at local markets are easily pathogenically infected because retailers do not keep them in proper food preservation equipment. In addition, food packaging using single-use plastic grocery bags is a burden for waste management and aggravates the “white pollution”. In this research, we created biodegradable bacterial cellulose membrane (BCm) loaded with raw bacteriocins that were collected from isolated lactic acid bacteria (LAB) and test their ability to preserveraw fish and meat. The 2mm thick and 94% wet BC membrane was obtained from the surface fermentation of Acetobacterxylinum in the medium containing 50% of coconut water and 15% sucrose after 03 days. The isolated LAB from sour cabbage, kimchi and yogurt were microscopically observed, biochemically characterized and species identified by mass spectrometry. The raw bacteriocin from Lactobacillus plantarum showing the most antimicrobial capability among the isolates could inhibit the growth of 3 tested strains of Escherichia coli, Staphylococcus aureus and Bacillus subtilis at the antimicrobial activity of 100 AU/ml by agar-well diffusion method. BCm treated with the bacteriocins of 100 AU/ml in 45 minutes was proved to be able to well preserve fish for 24 hours and pork for 18 hours at ambient temperatures, following Vietnam Standard for catfish fillet (TCVN 8338:2010) and for meat (TCVN 7046:2009).

Peltophorum pterocarpum is regarded as one of the most important medicinal plants in the traditional medicine system of Vietnam. However, scientific evidence for the antioxidant effects against lipid peroxidation and the potential effects in cancer of this plant are lacking. In our experiments, 70% ethanolic extracts of P. pterocarpum leaves (LPP) and stem bark (SPP) were evaluated for their low-density lipoprotein (LDL) oxidation and cytotoxic activity against cancer cell lines. Both LPP and SPP inhibited Cu2+-mediated LDL by increasing the lag time of conjugated diene formation and inhibiting the generation of thiobarbituric acid reactive substances (TBARS) in a dose-dependent manner. In cancer cells, LPP and SPP triggered the most potent cytotoxic effects against human leukemia cells, CRF-SBA and HL-60, with half-maximal inhibitory concentration (IC50) values ranging from 118.5 to 157.2 &micro, g/mL. SPP exhibited significant cytotoxicity against MIA PACA2, A549, and KG cell lines with IC50 values of 167.5, 244.1 and 255.0 &micro, g/mL, respectively. Meanwhile, LPP showed cytotoxic activity against KG with an IC50 value of 228.1 &micro, g/mL. SPP mediated cytotoxicity in HL-60 and CCRF-SBA cells through the activation of the apoptosis pathway, including the activation of caspases 3, and 9 and poly (ADP-ribose) polymerase (PARP). These results suggested that SPP may prevent the development and progression of atherosclerosis and leukemia in humans.

Paclitaxel (PTX), a compound extracted from the Pacific yew tree (Taxus brevifolia), is widely used as a natural-source cancer drug in the treatment of ovarian, breast and lung cancers. Previous studies showed that PTX had obvious effects on cancer cells, it blocks the cell cycle in its G1 or M phases by stabilizing the microtubules and preventing depolymerization. However, the use of PTX is inconvenient and associated with significant and poorly predictable side effects, due to its low bioavailability and poor water solubility. The aim of this study was to develop PTX-loaded soy lecithin nanoliposomes (PTX-LP) to improve its bioavailability. In this study, PTX-LP was prepared by thin film hydration method. The average size, polydispersity index (PDI), zeta potential and encapsulation efficiency (EE) of the PTX-LP were characterized. Results indicated that PTX-LP was able to loaded with suitable encapsulation efficiency values, nanometric particle size (100–200 nm), low polydispersity (less than 0.5), negative zeta potential, and slowly released up to 96 h. Therefore, the study expected that PTX-LP developed herein would serve as a potent drug carrier system for PTX in cancer therapy.

A 9-week feeding experiment was conducted to evaluate different dietary protein levels in juvenile Nile tilapia reared in either a biofloc (Bio-RAS) or clear water recirculating aquaculture system (CW-RAS). The fish were fed four isoenergetic (19 MJ kg−1) diets with graded levels of a fixed mixture of three protein sources (animal, plant, and microbial origin) and containing 23, 27, 31 or 35% crude protein. Triplicate groups of 20 juvenile tilapia (initial weight: 39.1 ± 2.5 g) were randomly assigned to 24 identical conical 500-L tanks equipped with feed waste traps. Twelve of the tanks were supplied with clear water purified by a mechanical and biological filter, denoted CW-RAS, and on average 15% daily replacement of water. The other 12 tanks were supplied with a biofloc suspension, maintained by a bioreactor system, denoted Bio-RAS, where the mechanical and biological filters were replaced with four serial 10 m3 open bioreactor tanks. In this later system only evaporated water was replaced. The bioreactor tanks were initially inoculated with Bacillus subtilis, and nutrients were supplied to achieve a C: N ratio of 10, supporting heterotrophic bacterial growth. Feed and protein intake, weight gain, specific growth rate, protein efficiency of fish in all treatments, and biomass of micro components in the bioreactor tanks, as well as apparent digestibility of dietary components, were determined at end of the experiment. Growth, feed intake and protein efficiency, especially if retention of the floc was included, was overall higher in the Bio-RAS than in the CW- RAS system. Feed conversion was influenced both by protein level and by the availability of biofloc, with a general lower value in the Bio-RAS and fish given higher protein containing diets. Apparent digestibility of total protein did not vary with the rearing system but was higher with higher dietary levels of crude protein. No significant effect was found for mortality or body index, except for hepato-somatic index and intestinal quotient index, with the latter being significantly higher in the fish given access to biofloc. In all fish given access to biofloc, given all other factors being equal, displayed higher and more feed efficient growth than fish kept in clear water with only access to fabricated diets. Our results tally with other studies using biofloc tank technology and reports from more commercial settings indicating that our data is valid also at a more general level.

Cassaine diterpenoids as erythrofordins A-C (1–3), pseudo-erythrosuamin (4), and erythrofordin U (5) isolated from the leaves of Vietnamese Erythrophleum fordii Oliver were tested cytotoxic activity against human leukemia cancer cells. The results showed that these metabolites exhibited dose-dependent cytotoxicity against human leukemia HL-60 and KG cells with IC50 values ranging from 15.2 ± 1.5 to 42.2 ± 3.6 µM. Treatment with erythrofordin B led to the apoptosis of HL-60 and KG cells due to the activation of caspase 3, caspase 9, and poly (ADP-ribose) polymerase (PARP). Erythrofordin B significantly increased Bak protein expression, but downregulated the anti-apoptotic protein Bcl-2, in HL-60 cells. In silico results demonstrated that erythrofordin B can bind to both the procaspase-3 allosteric site and the PARP-1 active site, with binding energies of −7.36 and −10.76 kcal/mol, respectively. These results indicated that the leaves of Vietnamese E. fordii, which contain cassaine diterpenoids, can induce the apoptosis of human leukemia cancer cells.

Low temperature plasmas at atmospheric pressure are usable on materials sensitive to high temperatures, (bio)materials that are not resistant to vacuuming or even fully drying, (bio)targets that are sensitive to significant current transfer. A great number of scientific publications has followed this rise in interest for atmospheric pressure plasmas and they most commonly address the discharge dynamics, densities of heavy species, at times gas temperature measurements, imaging of flow fields and rarely electron densities and electric field but very few on electric field measurements. This paper will give an overview of the recent work in the electric field measurements in atmospheric pressure plasma jets that operate in the ’bullet mode’ when in contact with various surfaces. The results focus on the comparison between the jets driven by 30 kHz sine voltage and jets driven by short high voltage pulses. Two measurement methods have been used that allow for comparison between the electric field in the gas phase and on the treated targets, which vary from dielectrics to liquids. Acknowledgement European Cooperation in Science and Technology Action COST TD1208 for financial support for a short-term scientific mission.

Low temperature plasmas at atmospheric pressure offers possibilities that were not accessible to plasma-based technologies for a long time, such as usage on materials sensitive to high temperatures, (bio)materials that are not resistant to vacuuming or even fully drying, (bio)targets that are sensitive to significant current transfer. In addition to the simplicity with which the plasma sources can be built and the ease with which they can be operated, lot temperature plasmas have become very popular in the recent years. A great number of scientific publications has followed this rise in interest for atmospheric pressure plasmas, covering different geometries of mostly dielectric barrier discharges (DBDs), used with or without gas flow and a wide range of excitation frequencies from Hz to MHz. Most commonly reports address the discharge dynamics, densities of heavy species, at times gas temperature measurements, imaging of flow fields and rarely electron densities and electric field but very few on electric field measurements. This paper will give an overview of the recent work in the electric field measurements in atmospheric pressure plasma jets that operate in the ’bullet mode’. A Helium jet with flow rates up to 2 SLM, in a low-power mode (up to 1 W dissipated in the discharge). The jet is run in the bullet mode where one plasma bullet is emitted per voltage period. The results fill focus on the comparison between the jets driven by 30 kHz sine voltage and jets driven by short high voltage pulses. Two measurement methods have been used that allow for comparison between the electric field in the gas phase and on the treated targets, which vary from dielectrics to liquids.

2′,4′-Dihydroxy-6’-methoxy-3′,5′-dimethylchalcone (DMC), a principal natural chalcone of Cleistocalyx operculatus buds, suppresses the growth of many types of cancer cells. However, the effects of this compound on pancreatic cancer cells have not been evaluated. In our experiments, we explored the effects of this chalcone on two human pancreatic cancer cell lines. A cell proliferation assay revealed that DMC exhibited concentration-dependent cytotoxicity against PANC-1 and MIA PACA2 cells, with IC50 values of 10.5 ± 0.8 and 12.2 ± 0.9 µM, respectively. Treatment of DMC led to the apoptosis of PANC-1 by caspase-3 activation as revealed by annexin-V/propidium iodide double-staining. Western blotting indicated that DMC induced proteolytic activation of caspase-3 and -9, degradation of caspase-3 substrate proteins (including poly[ADP-ribose] polymerase [PARP]), augmented bak protein level, while attenuating the expression of bcl-2 in PANC-1 cells. Taken together, our results provide experimental evidence to support that DMC may serve as a useful chemotherapeutic agent for control of human pancreatic cancer cells.

International audience; This report focuses on the dependence of electric field strength in the effluent of a vertically downwards-operated plasma jet freely expanding into room air as a function of the gas flow speed. A 30 kHz AC-driven He jet was used in a coaxial geometry, with an amplitude of 2 kV and gas flow between 700 sccm and 2000 SCCM. The electric field was measured by means of Stark polarization spectroscopy of the He line at 492.19 nm. While the minimum and the maximum measured electric fields remained unchanged, the effect of the gas flow speed is to cause stretching of the measured profile in space—the higher the flow, the longer and less steep the electric field profile. The portion of the effluent in which the electric field was measured showed an increase of electric field with increasing distance from the capillary, for which the probable cause is the contraction of the plasma bullet as it travels through space away from the capillary. There are strong indications that the stretching of the electric field profile with increase in the flow speed is caused by differences in gas mixing as a function of the gas flow speed. The simulated gas composition shows that the amount of air entrained into the gas flow behaves in a similar way to the observed behaviour of the electric field. In addition we have shown that the visible length of the plasma plume is associated with a 0.027 molar fraction of air in the He flow in this configuration, while the maximum electric field measured was associated with a 0.014 molar fraction of air at gas flow rates up to 1500 SCCM (4.9 m s−1). At higher flows vortices occur in the effluent of the jet, as seen in Schlieren visualization of the gas flow with and without the discharge.

Non-thermal atmospheric pressure plasma jets have been developed for use on thermosensitive targets at atmospheric pressure, for example polymers or for biomedical applications. Diagnostics on these plasma sources is challenging because of their transient nature, often associated jitter and very small volume. Electric fields, fundamental property essential for the understanding of the discharge, are not well known. In this talk two methods of electric field measurements will be shown applied to a He kHz-driven jet, one based on spectroscopy and one on polarimetry and the obtained results will be discussed.