State Management of Social Security in Vietnam

In recent years, Vietnam has made remarkable progress in ensuring social security, which is clearly shown through the development and good implementation of insurance policies, contributing to reducing difficulties and stabilizing people life and social welfare and people’s lives continue to be improved. However, in the context of international integration and Industrial revolution 4.0, state management of social security faces many challenges. This article clarifies the requirements of international integration and Industry revolution 4.0 for state management of social security

Integrated compensation model using a three-phase neutral point clamped inverter

Normally, when research on active compensation models, previous studies only assumed that the source of harmonics is nonlinear load. The nonlinear load here is fixed and balanced, the supply voltage is considered ideal, i.e. the three-phase source is balanced and there is no distortion. However, in reality, the above assumption is difficult to achieve. Therefore, this paper aims to design an integrated compensation model for different types of harmonic sources. The types of harmonic sources considered here include: harmonic sources generated from nonlinear load and source. The requirement of the integrated compensation model is to create a balanced three-phase voltage at the terminal of the load and the supply current must be a sinusoidal wave in phase with the source voltage. In order to reduce the loss caused by the inverter switching, this paper uses a three-level Neutral Point Clamped inverter. The simulation results performed on Psim software have demonstrated the effectiveness of the proposed integrated compensation model compared to the traditional integrated compensation model in reducing harmonics and stabilizing DC-bus voltage

Efficiency Performance of Hospitals and Medical Centers in Vietnam

The purpose of this paper is to analyze the efficiency performance of the hospitals and medical centers in Vietnam by using a non-parametric approach, namely the data envelopment analysis (DEA) model. The data from the Economic Census for Enterprises by the General Statistics Office of Vietnam (GSO) consists of 44 observations, which include 17 hospitals and 27 medical centers in different provinces and cities in 2002. The results indicate that the average scale efficiency of the hospitals was 77.4 percent, while that of the medical centers was 58.7 percent. Further, hospitals were clearly more efficient than medical centers due to some possible factors. Locations in Hanoi and Ho Chi Minh city had no influence on either overall technical efficiency or scale efficiency. Despite differences in the results of testing the impact of net capital-labor ratio on efficiency for hospitals and medical centers, these organizations appear to operate in labor-intensive ways

Efficiency of Construction Firms in Vietnam

This paper uses both parametric and non-parametric approaches to estimate technical efficiency for 2,298 construction firms in Vietnam in the database of the 2002 Economic Census for Enterprises by the General Statistics Office of Vietnam (GSO). It is found that results from both approaches are consistent, and they could help explain the performance efficiency of these firms. Estimates from the non-parametric approach (data envelopment analysis [DEA] model) and the parametric approach (stochastic frontier production function [SFPF] model) indicate that the average pure technical efficiency of these firms was about 60 percent (58.6% and 57.8% for DEA and SFPF, respectively). Models to test the factors influencing efficiency scores in both approaches show relatively similar results that state firms were more efficient than non-state ones, and location in Hanoi and Ho Chi Minh city did have impacts on efficiency scores. However, exploration of the net capital-labor ratio variable show that it did not influence efficiency scores in the DEA model, while it had clear influence in the SFPF model

Influence of Curing Regimes on Engineering and Microstructural Properties of Geopolymer-Based Materials from Water Treatment Residue and Fly Ash

Geopolymerization is a new method for treating water treatment residue (WTR) from water purification plants to reduce the amount of stored land in urban areas. Polymeric bond formation depends on the curing conditions. In this study, the curing conditions suitable for subsequent treatment to save energy consumption and production costs in the future application were investigated. The WTR had a high aluminosilicate content with low alkaline activity, so fly ash (FA) was added to FA and WTR mixtures in the ratio of 40 and 60 weight percent (% in wt.), respectively. The moisture content of the mixtures ranged in 12–15%, suitable for semi-dry pressing to form pellets. After this formation, the geopolymer samples were cured under different conditions (room temperature, microwave oven, in dryer at 110°C, and in autoclave with hydrothermal condition). The experimental results showed that the hydrothermal samples had better properties, such as pH<9, high stability of mechanical strength over 3.5 MPa, and soft coefficient over 0.75. The microstructural properties were investigated using modern analytical tools, such as XRD, SEM, FTIR, and NMR, to detect the chemical functional groups of the aluminosilicate networks in the geopolymer matrix and the close relationship among the properties and its microstructure

New quinazolinone-based Mannich bases: Synthesis and in vitro cytotoxic evaluation

This research presents the synthesis of new quinazolinone-based Mannich bases in good yields via a three-step procedure. The first step is the reaction of 6-hydroxyanthranilic acid 1 with an excess of acetic anhydride at 150°C for 2 h to afford benzoxazinone 2 in 87% yield. Compound 2 is then reacted with 4-aminophenol in DMSO at reflux for 7 h to give compound 3 in 75% yield. Finally, the reaction of 3 with paraformadehyde and secondary amines in ethanol affords new quinazolinone-based Mannich bases 4a-c and 5a-e in 55-70% yields. The structure of Mannich bases have been characterized by NMR and MS spectra. The bio-assay results show that some new Mannich bases exhibited weak to moderate cytotoxic activity against SKLu-1 and MCF-7 cell lines

SCREENING ANTIBACTERIAL ACTIVITY OF VIETNAMESE PLANT EXTRACTS AGAINST HUMAN PATHOGENIC BACTERIA

Objectives: Infectious diseases caused by bacteria are a leading cause of death worldwide. Hence, the objectives of the study are aimed to evaluate the antibacterial activity against five human pathogenic bacteria of methanolic extracts from 66 plants collected from Vietnam. Methods: The broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of methanol extracts of 66 plant species against five bacterial strains. Results: In this study, all the plant extracts were active against at least one train with MIC values ranging from 24 to 2048 μg/mL. Twenty-five plant extracts were active against all three Gram-positive bacteria (Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus). Of these, the extracts of Macaranga trichocarpa (Rchb. f. and Zoll.) Mull. Arg. (Euphorbiaceae), Calophyllum inophyllum L. (Clusiaceae) and Caryodaphnopsis baviensis (Lecomte) Airy Shaw (Lauraceae) exhibited the highest antibacterial activity (MIC =24–128 μg/mL), followed by extracts of Betula alnoides Buch.- Ham. e × . D. Don (Betulaceae), Acronychia pedunculata (L.) Miq. (Rutaceae), Croton alpinus A. Chev. ex Gagnep. (Euphorbiaceae) (MIC =64–256 μg/mL). Furthermore, the extract of Rhus chinensis Mill. (Anacardiaceae) and Annona reticulata L. (Annonaceae) exhibited potent antibacterial activity against the two Bacillus species (MIC =32–64 μg/mL). Conclusion: Results of this study reveal that plant extracts from Vietnam have highly antibacterial activity against Gram-positive bacteria. These results suggest that Vietnamese plant extracts may be a rich source of antibacterial drugs

Isolation and identification of triterpenoid compounds from Couroupita guianensis Aubl.

In this report, the extracts from the fruit and leaves of Couroupita guianensis were isolated using chromatographic methods and investigated for chemical composition. Four triterpenoid compounds were isolated and identified as betulinic acid, oleanolic acid, β-amyrin and friedelin. Their chemical structures were interpreted based on modern spectra such as MS, NMR and compared with previously published spectral data