Search

In this work, graphene oxide (GO) was prepared via the Hummers’ method, whereas SrFe12O19, SrFe12O19@Fe3O4, and SrFe12O19@Fe3O4@rGO were fabricated using the hydrothermal techniques. The samples' phase structure, surface morphology, magnetic properties, and electromagnetic wave absorption characteristics were studied and compared. Findings show that the Fe3O4 particles adhered to the surface of the SrFe12O19 hexagonal plates, and the combination of SrFe12O19@Fe3O4 foam flakes and two-dimensional graphene rGO could enhance the absorption electromagnetic wave performance. The composite SrFe12O19@Fe3O4@rGO sample exhibited an ideal impedance matching within the frequency f range of 11 GHz–12.4 GHz. The minimum reflection loss reached −62.3 dB at 12.2 GHz with a thickness of 2 mm. With a thickness of 2 mm, the effective absorption bandwidth obtained the value of −20 dB, covering a range of 9.3 GHz. The composite SrFe12O19@Fe3O4@rGO sample, which shows the highest performance both in reflectivity and bandwidth, can find potential application in microwave absorptions.

Indium-substituted yttrium iron garnet samples, Y3Fe5−xInxO12 (x = 0–0.7, step 0.1), were prepared using a citrate solgel method. Synchrotron X-ray diffraction (SXRD) measurements combined with the Rietveld refinement technique were used to investigate the crystallization, structure parameters and lattice distortion in the samples. Magnetization and Curie temperature of the samples were measured with the SQUID and VSM equipments. The non-magnetic indium ions were found to reside at the octahedral sites, leading to an increase of the total magnetization and a decrease in the Curie temperature. Molecular field coefficients Naa, Ndd and Nad were determined by fitting the experimental thermomagnetization curves in the framework of a two-sublattice ferrimagnetic model. The stiffness constant of the spin waves, D, in these samples was calculated based on the exchange interaction constants, Jij, and its temperature dependence was derived for the sublattice magetizations. The calculated results for D(T) are in good agreement with the experimentally measured data and are significantly large around room temperature.

Studies on how smoking media literacy (SML) is associated with susceptibility to smoking among adolescents in South Korea and Vietnam are scarce. Thus, we examined the association of SML with susceptibility to smoking among adolescents in these countries to initiate a collaborative global health program. In total, 460 adolescents (Vietnam: 277, South Korea: 183) aged 15-18 completed an online cross-sectional survey. SML was measured using the 15-item SML scale. Susceptibility to smoking was measured by three questions on future smoking and if offered a cigarette by a friend. A multiple logistic regression model explored the association of SML with susceptibility to smoking. The study revealed that higher SML was significantly associated with lower susceptibility to smoking among Vietnamese, but not South Korean adolescents. Further studies to identify pathways between other factors associated with SML and susceptibility to smoking are needed to develop culture-specific intervention strategies for smoking prevention.

Dy and Ho iron garnets in form of nanoparticles were synthesized by citrate sol-gel method. Phase formation, lattice constant and average crystallite sizes of the samples were determined via XRD measurements. Morphology and particle size distribution were studied by TEM and chemical composition was checked by EDX. Magnetic measurements in temperature range 5–600 K and in the maximum applied field of 50 kOe were carried out by using SQUID and VSM. Their magnetic parameters, including Curie temperature, magnetization compensation temperature, spontaneous magnetization, high-field susceptibility, magnetic coercivity were discussed in the framework of three interacting magnetic sublattices, magnetocrystalline anisotropy, core-shell model and compared to those of the bulk materials. Based on these analyses further evaluation on the crystallinity and homogeneity of the samples has been made.

Nghiên cứu nhằm xây dựng và thẩm định quy trình định lượng chì, cadimi trong rễ củ Địa hoàng 19 bằng phương pháp quang phổ hấp thụ nguyên tử. Kết quả nghiên cứu cho thấy giữa nồng độ chì, cadimi với độ hấp thụ có tương quan tuyến tính chặt, với nguyên tố chì dạng hàm là Y = 0,0138X + 0,1131, r = 0,9998 và với nguyên tố cadimi dạng hàm là Y = 0,1027X - 0,0037, r = 0,9999. Quy trình có độ đặc hiệu cao, độ lặp lại tốt với RSD < 5% và giới hạn phát hiện đối với Pb là LOD = 0,087 ppb, với Cd là LOD = 0,015 ppb; giới hạn định lượng với chì LOQ = 0,290 ppb, với cadimi LOQ = 0,049 ppb. Quy trình này phù hợp để định lượng Pb, Pb trong rễ củ Địa hoàng 19.

The current study was designed to investigate the anti-hypertensive effects of a standardised flavonoid extract from Diospyros kaki L.f leaves (DK extract) on cortisone acetate-induced hypertensive rats. Hypertension was induced in Wistar rats by subcutaneously injecting 2.5 mg cortisone acetate daily and by maintaining the rats on a 1% sodium chloride diet for a period of 28 days. The hypertensive rats were treated daily with DK extract (50 and 100 mg/kg of body weight; p.o.) or captopril (20 mg/kg of body weight; p.o.), a reference drug, for 14 consecutive days. The blood pressure and heart rate of awake rats were measured using a non-invasive tail-cuff method. The heart weight and left ventricular wall thickness of rats were measured. In vitro angiotensin-converting enzyme (ACE) inhibition activity of the DK extract and captopril were analysed. DK extract significantly and dose-dependently reduced systolic and diastolic blood pressure in the hypertensive rats. There were no significant changes observed in heart rate. The cortisone acetate-induced hypertensive rats had increased heart weight and left ventricular wall thickness. These actions were attenuated by the treatment of DK extract (100 mg/kg) and captopril. Moreover, DK extract inhibited ACE activity in vitro with an IC50 of 4.71±0.53 µg/ml. Our findings demonstrate that DK extract exerted anti-hypertensive effects and alleviated ventricular hypertrophy in the cortisone acetate-induced hypertensive rats and these actions occurred at least in part via ACE activity inhibition.

Grain sizes and minerals of sediments from the Gulf of Tonkin were evaluated from 30 surface samples and 50 samples from two cores. The distribution of grain sizes and minerals from these samples were determined to help understand sediment characteristics, origins, and environmental dynamics. There were five sediment types: fine and very fine sands, very coarse, coarse, and medium silts. Minerals in the sediment were identified as decreasing in terms of the content of quartz, illite, kaolinite, chlorite, feldspar, goethite, halite, calcite, gibbsite, aragonite, and montmorillonite. Contents of major minerals such as quartz, illite, kaolinite, and chlorite varied from nearshore to offshore; quartz was higher nearshore than offshore; illite, kaolinite, and chlorite from nearshore were lower than offshore; calcite and aragonite were low nearshore and higher in the offshore; goethite was lower offshore and higher nearshore; and, finally, halite was high offshore and low nearshore. Surface sediments were divided into three groups based on sedimentary environment characteristics: Group 1 was distributed nearshore with strong dynamics, Group 2 in bays and nearshore with weak dynamics, and Group 3 was distributed offshore with quiet dynamics. The origin of the sediments was weathering and erosion from the mainland and islands under the river and sea processes in the Gulf of Tonkin with quartz, illite, kaolinite, feldspar, chlorite, and montmorillonite found present in the sediment. Geochemical processes produced goethite, gibbsite, halite, and pyrite in the sediments while biological substances produced calcite and aragonite.

Bài nghiên cứu tìm hiểu hành vi thao túng lợi nhuận nhằm tránh lỗ và tránh suy giảm lợi nhuận so với năm trước của các doanh nghiệp niêm yết trên thị trường chứng khoán Việt Nam. Với dữ liệu báo cáo tài chính của 716 công ty phi tài chính niêm yết trong giai đoạn 2009-2016, kết quả chỉ ra có “quá nhiều” quan sát ngay sau ngưỡng lợi nhuận 0, hàm ý rằng các công ty có xu hướng thao túng lợi nhuận nhằm tránh lỗ. Kết quả cũng cho thấy các doanh nghiệp quy mô lớn, doanh nghiệp tăng trưởng cao, doanh nghiệp không được kiểm toán bởi một trong bốn công ty kiểm toán lớn (Big 4), hoặc doanh nghiệp không có sở hữu nhà nước là những doanh nghiệp có xu hướng thao túng lợi nhuận nhằm tránh lỗ nhiều. Tuy nhiên, nghiên cứu không tìm được bằng chứng về hành vi thao túng lợi nhuận nhằm tránh sụt giảm lợi nhuận so với năm trước.

Lithium nickel oxide (LNO) is an attractive positive electrode active material for lithium ion batteries (LIBs) due to its high reversible specific capacity and absence of cobalt. Nevertheless, it is prone to structural instabilities that lead to rapid capacity fading, safety concerns and shows in average a lower voltage than mixtures with cobalt, limiting its applicability to date. Herein this study introduces the sulfur‐based electrolyte additive, benzo[d][1,3,2]dioxathiole 2,2‐dioxide (DTDPh), to stabilize the LNO electrode and study its effects on interphase compositions by means of complementary electrochemical and spectroscopic techniques. Obtained results demonstrate an improved galvanostatic cycling performance in terms of cycle life and achievable specific discharge capacity that significantly outperform the common film‐forming additive vinylene carbonate (VC). The cycle life is increased from 102 to 147 cycles compared to the baseline electrolyte and the accumulated discharge energy until end of life is increased by 45%. This study furthermore provides strong evidence of a significant cross‐talk and negative interplay between DTDPh and VC when both are present in the electrolyte formulation. Mechanistic consideration based on density functional theory (DFT) calculations suggest the formation of mobile poly(VC) species, which is supported by the results of post mortem analysis of the resulting interphases. [ABSTRACT FROM AUTHOR]

Systematic review of articles published in 2018-2021 from the ScienceDirect database is done to discuss the significance of the Nudge theory for recent insights into the encouragement of waste separation at source among the households in Vietnam. The country has an institutional structure and a comprehensive legal framework and underpinnings in support to its waste management strategies for environmental protection and for the development of circular economy. In spite of this, Vietnam is beset with increasing waste problem. Synthesized information from the review supports the potential of nudges to induce waste separation at source among the households and to ensure broad social support and participation for the desired behavior. RandD is an essential process to determine the appropriate nudges that will drive the desired behavior. For Vietnam to induce waste separation at source among its households, nudge conceptualization, selection, configuration (including choice structure), administration (and conveyance), testing, and revision are critical with framing/messaging, symbolism, contextualization, association, and feedbacking, especially in structuring choices and methods of nudge implementation. Pitfalls in the use of nudges include shortfalls in the critical process of nudge configuration and administration as well as fatalistic mindsets, and non-consultative, non-inclusive and non-participatory approaches of determining the nudges. Vietnam has to pay attention to the critical considerations (including the involvement of experts) of creating nudges to be successful towards inducing waste separation at source for circular economy.

Sodium batteries are an attractive alternative for future energy storage as they can be produced with abundant and low-cost materials. Nonetheless, sodium-ion batteries (SIBs) are often composed of flammable and volatile carbonate-based liquid electrolytes. Polymer electrolytes have attracted significant attention as safer alternatives. Among polymer electrolytes, single-ion conductive polymer electrolytes (SIPEs) are considered particularly interesting because they can suppress dendrite growth, enabling high-performance (quasi)-solid-state sodium–(metal) batteries. In this work, a self-standing, flexible, quasi-solid-state SIPE is investigated, which is composed of sodium 4-styrene sulfonyl (trifluoromethanesulfonyl) imide (NaSTFSI), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) and pentaerythritol tetraacrylate (PET4A) blended with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). The SIPE membrane, including 50 wt% of molecular transporter, exhibits ionic conductivity of 1.4 × 10−5 S cm−1 and 1.3 × 10−4 S cm−1 at 20 °C and 90 °C, respectively, thermal stability up to 280 °C, electrochemical stability window up to 4.5 V vs. Na/Na+, and Na plating/stripping reversibility in symmetric Na‖Na cells. The manufactured SIPE implemented in Prussian White (PW)‖Na cells enables the delivery of 147 mA h g−1 of PW at 15 mA g−1 with a Coulombic efficiency of over 99%, which is comparable with the PW‖Na cells using liquid carbonate electrolyte, confirming the suitability of the designed SIPE for sodium–(metal) batteries. [ABSTRACT FROM AUTHOR]

We previously demonstrated that Panax notoginseng (pNG) root extract treatments exerted neuroprotective effects on brain injuries using middle cerebral artery occlusion in mice. The present study aims to investigate the neuroprotective effects of PNG extract and its ginsenosides Rg1 and Rb1 on ischemic neuronal damage caused by oxygen and glucose deprivation (OGD) in mouse organotypic hippocampal slice cultures (OHSCs). Before the experiments, hippocampal slices collected from 7-day-old Swiss mice were cultured for 7 days. OGD was triggered in OHSCs for 30, 60, or 90 min with the aim of finding the optimal period of OGD for drug testing. PNG extract (10, 30 µg/ml), ginsenosides Rg1 and Rb1 (5, 25 µM), or MK-801 25 µM, a reference drug, was added to the culture medium 24 h before OGD and these treatments were continued for 24 h after the optimum 60-min period of OGD. After 24 h of OGD exposure, the measurement of propidium iodide uptake was analysed in OHSCs to evaluate neuronal cell damage. The results showed that OGD time-dependently increased PI uptake of the OHSCs. PNG 30 µg/ml treatment reduced the OGD-induced neuronal cell damage in OHSCs. Ginsenosides Rg1 25 µM, Rb1 (5, 25 µM), as well as MK-801 (25 µM) significantly inhibited PI uptake 24 h after OGD exposure. However, ginsenoside Rg1 5 µM did not show any significant effects on the OGD-induced neuronal cell damage. These findings indicated that ginsenosides Rg1 and Rb1 contributed to the neuroprotective effects of PNG against ischemic damage in OHSCs and the neuroprotective effect of ginsenoside Rb1 was stronger than that of ginsenoside Rg1.

The objective of the study was to measure poverty in a multi-dimensional poverty approach to measure multi-dimensional poverty indicators in Vietnam and the economic regions of Vietnam. Thereby, it attempts to analyze and assess the multi-dimensional poverty in Vietnam and the economic regions in 2014. The study also analyzes the factors that affect the ability of a household that falls into multi-dimensional poverty in Viet Nam. The authors used cross-sectional data from the Vietnam Household Living Standard Survey (VHLSS) in 2014 results of the General Statistics Office to calculate and assess the multi-dimensional poverty status. In addition, the binary logistic model is used to determine the relationship and quantify the influence of demographic factors and socio-economic factors on the probability of one household of multi-dimensional poverty. From the research results, recommendations and policy implications are introduced to reduce multi-dimensional poverty and the depreciation of each poverty dimension in Vietnam and the economic regions.

This is a preliminary study of a material comprising gelatin (Gel), silver nanoparticles (AgNPs) and curcumin (Cur) aimed for wound-healing treatment. Gelatin was used to stabilize AgNPs and encapsulate curcumin to form a therapeutic composite (GelCurAg) for their strong bactericidal and antioxidant properties. GelCurAg formulations with different gelatin concentrations were characterized to attain information about their physiochemical properties and the loading efficiency of therapeutic agents. In vitro assessment of GelCurAg focused on antibacterial, antioxidant and cytotoxic aspects. The results suggested that Gel1CurAg (synthesized from 1% gelatin solution) could be utilized as potential therapeutic agents in treating infectious wound owing to its bactericidal and antioxidant effects and low toxicity for clinical uses.

Celastrus hindsii Benth., a medicinal plant celebrated for its traditionally medicinal and practically therapeutic properties, has been used for generations in Vietnam to support the treatment of ulcers, tumors, and inflammation. The difference between several phenotypes, primarily identified as Broad Leaf (BL) and Narrow Leaf (NL), has been clarified by convincing scientific evidence through our previous proteomics study, which also revealed several bioactive proteins and peptides. Therefore, based on the findings, this study further investigated their therapeutic properties using a bioinformatics tool (BLASTP) and analyzing literature data. The results showed the distinguished variations in protein profile between the NL and BL proteomes and revealed five significant proteins with therapeutic properties. Of these, three proteins can have anti-tumor and anti-inflammatory activity and have been proven effective in cancer treatment. Therefore, C. hindsii, particularly the BL phenotype with elevated levels of therapeutic proteins, could be a promising plant candidate for future intensive research and applications for cancer treatment. [ABSTRACT FROM AUTHOR]

The genus Chlamydia comprises obligate intracellular bacteria that infect a wide variety of hosts, with infection leading to a range of diseases in humans and animals; they thus constitute a major public health threat. Among the members of the Chlamydiaceae family, Chlamydia suis, C. abortus, C. pecorum, and C. psittaci represent the most important pathogenic species infecting a large range of hosts and are a well-established threat to livestock. Information regarding the circulation of Chlamydia species in ruminants from Vietnam is lacking. In this study, DNA extracted from 60 blood samples collected from goats in Hue province was used for Chlamydia spp. identification by classic PCR and Sanger sequencing. Chlamydia spp. were detected in eleven samples (18.3%) and C. abortus and C. psittaci were molecularly identified by sequencing. Despite the limited sample size in this study, findings point out the relevance of ruminants as hosts of chlamydial species in Central Vietnam and the importance of monitoring chlamydial strains through the activation of surveillance programs in this country. The need for a deeper evaluation of human and animal health risk analysis in terms of chlamydiosis should be also considered.