DIESEL OIL UTILIZING-BIOSURACTANT PRODUCING BACTERIAL ISOLATE AND CHARACTERISTICS OF PRODUCED BIOSURFACTANTS TOWARD BIOREMEDIATION APPLICATION

Joint Research on Environmental Science and Technology for the Eart

Do Corporate Social Responsibilities Support Its Financial Performance? Evidence of the Listed Firms in Vietnam

In the latest decades, corporate social responsibilities (CSR) are incrementally noticed in emerging countries regarding to the surge of globalization and the advance of social concerns. However, there exist opposing arguments on how CSR practices influence a firm’s financial performance (CFP), either in theoretical or empirical perspectives, causing many managers’ hesitation in CSR engagement. This study, therefore, examines the impacts of CSR on CFP, considering the individual effect of each CSR endeavor by using the data from listed firms’ financial statements during the period 2015-2019 and panel regression analysis methods. The findings reveal inconstant effects of different CSR activities on CFP. Specifically, a firm’s fulfillment of shareholders’ and customers’ interests contributes to raise its profitability, while its engagement in the benefits of employees and creditors causes a reduction in financial returns. Interestingly, the correlations between firms’ responsibilies towards regulators and suppliers and CFP are statistically insignificant. Furthermore, we make pairwise marginal comparisons to identify the distinctions of CSR-CFP relations across industries. The results only indicate that listed firms in Utilities sector have the lower level of CSR intensity than those in Consumer Discretionary and Consumer Staples sectors. The implications and limitations are also discussed in this study

Multiple-Symbol Differential Detection for Spatial Modulation

Approximately 3 dB Signal-to-Noise Ratio (SNR) loss is always paid with conventional Differential Spatial Modulation (DSM) as compared to coherent Spatial Modulation (SM). In this paper, a Multiple-Symbol Differential Detection (MSDD) technique is proposed for DSM systems to mitigate the loss due to differential detection. The new scheme can greatly narrow the 3 dB performance gap by extending the observation interval for differential decoding. The technique uses maximum-likelihood sequence detection instead of traditional symbol-by-symbol detection, and is carried out on the slow, flat Rayleigh fading channel. A generalized decision metric is derived for an observation interval of arbitrary length. It is shown that for a moderate number of symbols, MSDD provides approximately 1.5 dB performance improvement over the conventional differential detection. In addition, a closed-form pairwise error probability and approximate bit error probability (BEP) are derived for multiple-symbol differential spatial modulation. Results show that the theoretical BEP matches well the simulated one. The BEP is shown to converge asymptotically with the number of symbols in the observation interval to that of the differential scheme with coherent detection

Optimization of protein extraction from "Cam" rice bran by response surface methodology

"Cam" rice bran was considered a waste product from rice, which is rich in natural compounds and protein owing to its outstanding nutritional value. This study aimed to establish an optimization model for extracting protein from rice bran, with two responses: extraction yield (%) and protein content (%). The variable parameters included were pH (8.5-9.5), stirring time (3.5-4.5 h), and enzyme incubation temperature (85-95°C). The coefficient of determination for both models were above 0.95, indicating a high correlation between the actual and estimated values. The maximum extraction yield and protein content were achieved when the conditions were set at pH of 9.02, stirring time of 4.02 h, and extraction temperature of 90.6°C. Under these optimum conditions, the predicted protein extracted from rice bran was 43.03% (moisture <13.0%), with an extraction yield of 15.9%. The findings of this study suggested that this protocol can enhance the utilization of rice bran and might be employed on a large scale in the food industry to exploit the nutritional source

NGHIÊN CỨU KHẢO SÁT VÀ ĐÁNH GIÁ CÁC ĐIỀU KIỆN ẢNH HƯỞNG XỈ THÉP HẤP PHỤ VÀ LOẠI BỎ ARSEN TRONG NƯỚC

This paper presents the results of this research which utilizes solid waste resources in the environment, namely steel slag, to adsorp and remove arsenic in water. The study conducted empirical processes based on the processes in the experimental conditions affecting arsenic adsorption and removal by steel slag in contaminated water: concentration, steel slag size, steel slag weight, pollution concentration, temperature, symbiotic ions. The research results show: The lower initial solution concentration is, the more easily adsorption equilibrium can achieve, the higher initial concentration is, the longer it takes to reach adsorption equilibrium; the smaller steel slag particle is, the more easily adsorption equilibrium can reach; the larger particle size, the longer the time to reach adsorption equilibrium; the more increasing the number of steel slag particles, the greater the pollutant adsorption, the higher the removal efficiency; initial pH concentration affects As adsorption of steel slag (III); influence of temperature on As adsorption of steel slag (III) is not clear; different ions (NO3-, Cl‑, F-, SO42- and PO43-) intervene in As adsorption of steel slag (III) in solution. Thus, the choice of steel slag as the material to adsorb and remove arsenic in water is the optimal method, bringing economic efficiency, environmental protection and practical application.Bài báo trình bày kết quả nghiên cứu này là tận dụng nguồn chất thải rắn trong môi trường là xỉ thép đưa vào hấp phụ và loại bỏ arsen trong nước. Việc nghiên cứu thực hiện các quy trình thực nghiệm theo các quy trình thực nghiệm ở các điều kiện ảnh hưởng đến tính năng xỉ thép hấp phụ và loại bỏ arsen trong nước ô nhiễm: nồng độ, kích cỡ, khối lượng hạt xỉ thép cần thiết, nồng độ ô nhiễm, nhiệt độ, các ion cộng sinh. Kết quả nghiên cứu cho thấy: nồng độ dung dịch ban đầu càng thấp cân bằng hấp phụ càng dễ đạt được, nồng độ dung dịch ban đầu càng cao thì phải mất thời gian dài mới đạt cân bằng hấp phụ; kích thước hạt xỉ thép càng nhỏ cân bằng hấp phụ càng dễ đạt đến, kích thước hạt lớn thì thời gian đạt cân bằng hấp phụ sẽ kéo dài; lượng hạt xỉ thép gia tăng càng cao thì hấp phụ lượng chất ô nhiễm càng lớn, hiệu quả loại bỏ càng nhiều; nồng độ pH ban đầu ảnh hưởng đến tính năng xỉ thép hấp phụ As (III); ảnh hưởng của nhiệt độ đến tính năng xỉ thép hấp phụ As (III) không rõ ràng; các ion khác nhau (NO3-, Cl-, F-, SO42- và PO43-) can thiệp đến tính năng xỉ thép hấp phụ As (III) trong dung dịch. Như vậy, lựa chọn xỉ thép làm vật liệu hấp phụ và loại bỏ arsen trong nước là phương thức tối ưu, mang lại hiệu quả kinh tế, bảo vệ môi trường và tính ứng dụng cao có thể đưa vào áp dụng thực tiễn

Investigation of anti-inflammatory lignans from the leaves of Symplocos sumuntia Buch-Ham ex D Don (Symplocaceae)

Purpose: To investigate the anti-inflammatory activity of Symplocos sumuntia Buch.-Ham. ex D. Don and identify the main secondary metabolites responsible for this effect.Methods: The in vitro anti-inflammatory activity of the plant extract and isolated compounds was determined in terms of the ability to inhibit the production of nitric oxide (NO), and expressions of iNOS and COX-2 proteins in RAW264.7 cells stimulated by lipopolysaccharide (LPS). Compounds were isolated and identified by spectroscopic methods.Results: The methanol extract of S. sumuntia leaves showed strong inhibitory effects on nitric oxide (NO) production and expression of iNOS and COX-2 in LPS-induced RAW264.7 cells. A phytochemical assay-guided fractionation of the methanol extract of S. sumuntia leaves led to the isolation of four lignans which are arctigenin (1), matairesinol (2), monomethylpinoresinol (3) and pinoresinol (4). These compounds were identified for the first time from S. sumuntia. All four compounds inhibited the production of nitric oxide (NO), with arctigenin showing the most potent activity with half-maximal inhibitory concentration (IC50) value of 4.08 μM.Conclusion: S. sumuntia is a promising source of anti-inflammatory agents, which may clarify to the therapeutic use of this plant in Vietamese traditional medicine.Keywords: Symplocos sumuntia, Symplocos caudata, Lignan, Arctigenin, Anti-inflammator

Optimization of culture conditions of Streptomyces antibioticus strain 1083 to improve the antimicrobial activity against Aeromonas hydrophila

Fish is a healthy, high protein and low fat food that encourages the health and growth of people, especially children. However, in fact fish is very sensitive to many diseases which affects the productivity and quality of fish. Therefore, identifying the cause of the diseases and finding preventive measures become an urgent task today. In the previous study, we isolated Streptomyces antibioticus strain 1083 that has the ability to antagonize Aeromonas hydrophila - a pathogenic bacterium in fish. Based on the obtained results, we continue to perform this study to determine optimal conditions for the culture of S. antibioticus strain 1083 in order to produce antimicrobial compounds against A. hydrophila. The production of antagonists by the strain 1083 was optimized by controlling the condition of different inoculations such as media, pH, temperature and incubation period. The results indicated that International Streptomyces Project 2 (ISP2) was the best medium for S. antibioticus strain 1083 to produce the highest antimicrobial activity against A. hydrophila with 32 mm in diameter of inhibited zone. The actinomycete strain 1083 could express the maximum antimicrobial activity when they were incubated in shaker incubator (200rpm) at 40oC with pH8 in 8 days. The ability of the actinomycete strain in antagonism against A. hydrophila was evaluated by adding different culture medium volume of S. antibioticus strain 1083. With adding 10% cultured solution volume of S. antibioticus strain 1083 into the culture medium of A. hydrophila, after 1 day of inoculation the number of pathogenic bacteria cells were completely eliminated

Impact of Agency Costs on Firm Performance: Evidence from Vietnam

An assumption in agency costs theory is that agency costs can exert a negative impact on firm performance. In this study, we examine the impact of agency costs on firm performance of Vietnamese listed companies. Our sample includes 736 companies in Vietnam during the period om 2010 to 2015. We find that agency costs exert a negative impact on firm performance. Our results are robust to alternative econometric models, including an instrumental variables technique and a system generalized method of moment model. In addition, we show that a debt instrument can be a useful tool to reduce the negative impact of agency costs on firm performance

Kakvoća tjestenine bogate vlaknima, obogaćene prahom kore lubenice različitih veličina čestica

Research background. Watermelon rind, a by-product of watermelon juice processing, contains large amounts of dietary fibre and phenols with antioxidant capacity. The use of agro-industrial by-products would both improve economic benefits and reduce environmental emissions. The aim of this research is to examine the effect of the particle size of watermelon rind powder on the quality of high-fibre pasta. Experimental approach. The nutritional, physical and physicochemical quality of three samples of watermelon rind powder, sieved through three sieves with aperture size of 400, 210 and 149 μm, were analysed. Durum wheat semolina with watermelon rind powder mass fraction of 10 % were mixed and used to make pasta. Nutritional, textural and cooking quality, sensory acceptability, in vitro glycaemic index and antioxidant bioaccessibility of high-fibre pasta with added watermelon rind powder of different particle sizes were evaluated and compared. Results and conclusions. When the sieve aperture size was reduced from 400 to 149 µm, the soluble dietary fibre and total phenolic contents of watermelon rind powder were increased by 35 and 15 %, respectively, while its insoluble dietary fibre content was decreased by 21 %. Decrease in sieve aperture size from 410 to 149 µm reduced phenolic bioaccessibility of the fortified pasta from 63 to 57 %, but enhanced its predicted glycaemic index from 50 to 69. It also decreased the pasta hardness by 13 %, but improved its elongation rate and tensile strength by 13 and 40 %, respectively. The finer the particles of the watermelon rind powder, the longer the optimal cooking time, the higher the water absorption index, and the lower the cooking loss of the supplemented pasta. Consumers did not notice any significant differences in the overall acceptability among all pasta samples. Novelty and scientific contribution. The particle size of the watermelon rind powder had a major effect on nutritional value, texture and cooking quality of the fortified pasta. In particular, the predicted glycaemic index and antioxidant bioaccessibility of high-fibre pasta were significantly affected by the particle size of the dietary fibre material used in the recipe.Pozadina istraživanja. Kora lubenice, nusproizvod prerade soka lubenice, sadržava velike količine prehrambenih vlakana i fenola s antioksidacijskim svojstvima. Korištenjem agroindustrijskih nusproizvoda poboljšala bi se ekonomska učinkovitost procesa i smanjila emisija u okoliš. Svrha je ovog istraživanja bila ispitati utjecaj veličine čestica praha kore lubenice na kakvoću tjestenine bogate vlaknima. Eksperimentalni pristup. Ispitane su nutritivna, fizikalna i fizikalno-kemijska kakvoća triju uzoraka praha kore lubenice, prosijanih kroz tri sita veličine otvora 400, 210 i 149 μm. Krupica od durum pšenice pomiješana s 10 % praha kore lubenice upotrijebljena je za izradu tjestenine. Procijenjeni su i uspoređeni sljedeći parametri: nutritivna i teksturalna kakvoća te ona nakon kuhanja, senzorska prihvatljivost, in vitro glikemijski indeks i antioksidacijska biološka raspoloživost tjestenine bogate vlaknima s dodatkom praha kore lubenice različitih veličina čestica. Rezultati i zaključci. Smanjenjem veličine otvora sita s 400 na 149 µm povećali su se udjel topljivih prehrambenih vlakana za 35 % i ukupni udjel fenola u prahu kore lubenice za 15 %, dok se udjel netopljivih prehrambenih vlakana smanjio za 21 %. Smanjenjem veličine otvora sita s 400 na 149 µm smanjila se biološka raspoloživost fenola iz obogaćene tjestenine sa 63 na 57 %, ali se njezin predviđeni glikemijski indeks povećao s 50 na 69. Također se smanjila tvrdoća tjestenine za 13 %, no poboljšala se njezina rastezljivost za 13 % i vlačna čvrstoća za 40 %. Što su čestice praha kore lubenice bile sitnije, to je dulje bilo optimalno vrijeme kuhanja, veći je bio indeks upijanja vode i manji gubitak proizvoda nastao kuhanjem. Potrošači nisu primijetili nikakve bitne razlike u ukupnoj prihvatljivosti uzoraka obogaćene tjestenine. Novina i znanstveni doprinos. Veličina čestica praha kore lubenice uvelike je utjecala na nutritivnu vrijednost, teksturu i kakvoću obogaćene tjestenine nakon kuhanja. Konkretno, veličina čestica prehrambenih vlakana u materijalu korištenom u recepturi bitno je utjecala na predviđeni glikemijski indeks i antioksidacijsku biološku raspoloživost tjestenine bogate vlaknima

Why adaptation falters:principles for climate change adaptation policy assessment in Vietnam

PurposeRecognition that not every climate adaptation policy is a good one has shifted attention to new tools and methods to measure the adequacy and effectiveness of adaptation policies. This study aims to propose and apply and applies an innovative adaptation policy assessment framework to identify the extent to which climate adaptation policies in Vietnam exhibit conditions that are likely to ensure a sufficient, credible and effective adaptation.Design/methodology/approachIn total, 21 conditions, categorized under five normative principles and covering critical issue areas in adaptation domain, form the climate adaptation policy assessment framework. The principles were double-checked and tested in case studies through observations and analyses of policy documents to ensure that each condition should be distinct and not overlapping across principles. To see if the principles and attendant conditions were able to capture all relevant aspects of adaptation, the authors used structured expert judgment. In total, 39 policy documents pertaining to climate change adaptation were selected for qualitative document analysis. In-depth interviews with local officials and experts were conducted to address data gaps.FindingsThe study reveals major weaknesses constituting a reasonably worrisome picture of the adaptation policies in Vietnam since several critical conditions were underrepresented. These results shed new light on why some adaptation policies falter or are posing adverse impacts. The findings suggest that a sound policy assessment framework can provide evidence on what effective adaptation policy looks like and how it can be enabled. The framework for climate adaptation policy assessment in this study can be easily adjusted and used for different socio-environmental contexts in which new conditions for policy assessment might emerge.Social implicationsThe findings show underlying weaknesses constituting a reasonably worrisome picture of the adaptation regime in Vietnam. In the absence of mechanisms and measures for accountability and transparency in policy processes, adaptation in Vietnam appears more likely to be prone to maladaptation and corruption. While solving these problems will not be easy for Vietnam, the government needs to evaluate whether the short-term gains in sustaining the existing adaptation policies really make progress and serve its long-term climate-adaptive development goals.Originality/valueAlthough interpretations of adaptation effectiveness may be very divergent in different normative views on adaptation outcomes, the authors argue that a common, agreed-upon effectiveness can be reached if it is clearly defined and measurable in adaptation policies. Thus, the climate adaptation policy assessment framework proposed in this study is critical for policymakers, practitioners, donors and stakeholders dealing with adaptation to better understand the weaknesses in policymaking processes, pinpoint priority areas of action and timely prevent or prepare for possible adverse impacts of policies