Red-emitting Ba2Si5N8Eu2+ conversion phosphor: A new selection for enhancing the optical performance of the in-cup packaging MCW-LEDs

In this research, the influence of the red-emitting Ba2Si5N8Eu2+ convention phosphor on the optical performance of the 7,000K and 7,700K in-cup packaging multi-chip white LEDs (MCW-LEDs) is investigated. The effect of the red-emitting Ba2Si5N8Eu2+ convention phosphor is demonstrated based on Mie Theory by Mat Lab and Light Tools software. The research results indicated that the optical performance of MCW-LEDs was crucially affected by the red-emitting Ba2Si5N8Eu2+ phosphor's concentration. This paper provides an essential recommendation for selecting and developing the phosphor materials for MW-LEDs manufacturing.Web of Science51art. no. 148615

Epidemiology of Leprosy in Vietnam and the Effectiveness of Multidrug Therapy (MDT) in the Management of the Disease

Leprosy is a chronic infection caused by the acid-fast, rod-shaped bacillus Mycobacterium leprae. Leprosy can be considered connected diseases that primarily affect the superficial tissues, especially the skin and peripheral nerves. The social and psychological effects of leprosy, as well as its highly visible debilities and sequelae, have resulted in a historical stigma associated with leprosy. Vietnam has seen a highly significant decrease in the prevalence rate (PR) of leprosy since 1983. From 1983 onwards, with the introduction of multidrug therapy (MDT), the prevalence of the disease has dropped to less than one case per 10,000 individuals from 1995. After over two decades, a total of 109 cases were registered with a prevalence rate of 0.01 per 10,000 population in 2017. It is clear that over the past 35 years, the profile of leprosy in Vietnam has been changed significantly followed by the treatment with MDT. Leprosy has become a rare disease in Vietnam. This chapter presents the trend in the epidemiology of leprosy in Vietnam from 1983 to 2018 and also mentions the effectiveness of multidrug therapy (MDT) in the management of this disease. Based on individual records and annual reports, the prevalence of registered cases, the number of new cases detected yearly, their sex, age, classification (MB, multibacillary; PB, paucibacillary) and disability status are carefully presented

Determinants Influencing Liquidity of Listed Steel Firms in Vietnam

This study is conducted to investigate the impact levels of determinants influencing liquidity of listed steel firms on Vietnam Stock Exchange. Data were collected from audited financial statements of 25 listed food processing firms from 2014 to 2017. This research employs the least squares method (OLS) and tests to determine the influence of factors on the liquidity of listed sample firms. The results indicate that return on assets (ROA), operating period (AGE) and asset structure (AS) have positive impacts on the liquidity. In contrast, the firm size and debt ratio has the opposite effects. Based on the findings, a number of recommendations are proposed to increase the liquidity ratio of listed firms in the future. Keywords: Liquidity, steel firms, determinants, Vietnam Stock Exchange DOI: 10.7176/EJBM/11-7-10 Publication date:March 31st 201

US-China rivalry in Southeast Asia region: a study on the South China Sea case

Southeast Asia is one of the places where fierce rivalry is taking place between the two leading powers in the world today - the US and China. The US-China rivalry in this region takes place in key fields, from politics - diplomacy, economy, security - defense to "soft power", the most prominent of which is the South China Sea issue. This article analyzes the strategic importance of the South China Sea in the policy of the US and China, the competition between the US and China in Southeast Asia in general, and the South China Sea in particular. To achieve this goal, the authors use research methods in international relations to analyze the main issues of the study. In addition to reviewing previous scholarly research and reviews, the authors use a comparative approach to assess the interactions between theory and data. The authors believe the data is important for accurately assessing the strategic competition between the US and China in Southeast Asia and the South China Sea. The rise of China in the early years of the XXI century strongly influenced the adjustment of the US policy in Southeast Asia and the powerful US-China rivalry in this region and the South China Sea. This rivalry is becoming increasingly complicated, and geopolitical conflicts between major powers are possible in the following years

Ecological factors associated with dengue fever in a central highlands Province, Vietnam

<p>Abstract</p> <p>Background</p> <p>Dengue is a leading cause of severe illness and hospitalization in Vietnam. This study sought to elucidate the linkage between climate factors, mosquito indices and dengue incidence.</p> <p>Methods</p> <p>Monthly data on dengue cases and mosquito larval indices were ascertained between 2004 and 2008 in the Dak Lak province (Vietnam). Temperature, sunshine, rainfall and humidity were also recorded as monthly averages. The association between these ecological factors and dengue was assessed by the Poisson regression model with adjustment for seasonality.</p> <p>Results</p> <p>During the study period, 3,502 cases of dengue fever were reported. Approximately 72% of cases were reported from July to October. After adjusting for seasonality, the incidence of dengue fever was significantly associated with the following factors: higher household index (risk ratio [RR]: 1.66; 95% confidence interval [CI]: 1.62-1.70 per 5% increase), higher container index (RR: 1.78; 95% CI: 1.73-1.83 per 5% increase), and higher Breteau index (RR: 1.57; 95% CI: 1.53-1.60 per 5 unit increase). The risk of dengue was also associated with elevated temperature (RR: 1.39; 95% CI: 1.25-1.55 per 2°C increase), higher humidity (RR: 1.59; 95% CI: 1.51-1.67 per 5% increase), and higher rainfall (RR: 1.13; 95% CI: 1.21-1.74 per 50 mm increase). The risk of dengue was inversely associated with duration of sunshine, the number of dengue cases being lower as the sunshine increases (RR: 0.76; 95% CI: 0.73-0.79 per 50 hours increase).</p> <p>Conclusions</p> <p>These data suggest that indices of mosquito and climate factors are main determinants of dengue fever in Vietnam. This finding suggests that the global climate change will likely increase the burden of dengue fever infection in Vietnam, and that intensified surveillance and control of mosquito during high temperature and rainfall seasons may be an important strategy for containing the burden of dengue fever.</p

Isolation and production of polyhydroxybutyrate (PHB) from Bacillus pumilus NMG5 strain for bioplastic production and treatment of wastewater from paper factories

Polyhydroxybutyrate (PHB) has the potential to replace traditional plastics and limit environmental pollution caused by plastic waste. This study combined wastewater treatment with PHB production to reduce costs. Bacteria capable of synthesizing PHB were isolated from paper mill wastewater and identified using Matrix Assisted Laser Desorption/Ionization–Time of Flight (MALDI-TOF) mass spectrometry and 16S rRNA gene analysis. Bacillus pumilus NMG5 strain was found to have a good yield in modified Nutrient Broth culture, reaching 42.28% of dry biomass. The PHB product was analyzed using FTIR spectroscopy and 1H NMR spectroscopy. The bacterial strain was also tested for its ability to treat paper mill wastewater, and it showed impressive results in terms of biochemical oxygen demand (COD), total nitrogen, and total phosphorus, with efficiencies of 95.93%, 79.36%, and 83.55%, respectively. The study found that wastewater treatment combined with PHB production was a promising solution to reduce costs and limit environmental pollution. The bacterial strain B. pumilus NMG5 had a high yield of PHB, and the PHB product was of high quality, as confirmed by FTIR and 1H NMR spectroscopy. Furthermore, the bacterial strain showed impressive results in treating paper mill wastewater with high COD, total nitrogen, and total phosphorus efficiencies. These results suggest that this harmless bacterium could be used in paper mill wastewater treatment systems to produce PHB, providing a sustainable and environmentally friendly solution

DETERMINATION THE PRIORITY OF FACTORS INFLUENCING OVERSEAS INVESTMENT DESTINATIONS OF BUSINESSES USING AN ANALYTIC HIERARCHY PROCESS METHOD

Because of the great benefits overseas investment brings, countries and businesses are increasingly concerned with the question of an ideal investment destination. Many studies have shown that, factors of the consumption market, the infrastructure and resources, economic and political environment have a significant impact on the decision to choose an investment location, however the priority order of these factors are different for various research spaces. By studying the specific case of Viettel Group - one of the largest telecommunications groups in Vietnam that is having many international investment activities in recent years, the study has been verified the priority order of factors influencing the decision to choose an overseas investment location of this corporation. The research outcomes show that the group of factors that have the most influence on investment decisions is the group "Consumption market", more specifically, the sub-factor "Market Size" is considered more than the others.    Keywords: Investment Destinations, Foreign Investment Decision, Analytic Hierarchy Process

A Study on Factors Impacting on Profitability: The Case of Vietnam

This study is conducted to investigate factors influencing the profitability of the Vietnamese food processing firms. Data was collected from audited financial statements from listed food processing firms on the Vietnam Stock Exchange. Panel regression model was applied in this study (PLS). The testing methods used in this research were Pearson model; Modified Wald Test, Wooldridge test (for autocorreclation in panel data), Hausman model, especially the relationship between FEM and REM as well as Multicollinearity test based on VIF coeficient. The results shows that DR, SDR and LDR have negative impacts on profitability. In contrast, TDTELT have positive impacts on the profitability. FATA and SIZE impact return on asset (ROA) without statistical significance. SIZE has positive impact on return on equity (ROE) while it impacts negatively on profit margin (PM). Moreover, AGE, GDP growth, and inflation do not have impact on profitability. Keywords: Factors, Return on assets, Food processing firms, Vietnam DOI: 10.7176/RJFA/11-10-07 Publication date:May 31st 202