Effect of tartrazine dye on micellisation of cationic surfactants: conductometric,spectrophotometric, and tensiometric studies

The interactions between anionic dye (tartrazine) and cationic surfactants (dodecyltrimethylammonium bromide and cetyltrimethylammonium bromide) have been studied by conductometric, spectrophotometric, and tensiometric techniques. The conductance and surface tension of dodecyltrimethylammonium bromide and cetyltrimethylammonium bromide in pure water as well as in aqueous tartrazine when plotted with surfactant concentration gave values of the critical micelle concentration at different temperatures. As well as increasing the length of the carbon chain of surfactants, the presence of tartrazine reduces the critical micelle concentration. From specific conductivity data, the counterion dissociation constant, standard free energy, enthalpy, entropy of micellisation, surface excess concentration, surface tension at critical micelle concentration, minimum area per molecule, surface pressure at critical micelle concentration, and Gibbs energy of adsorption were evaluated. Spectroscopic studies reveal that the binding of dye to micelles brings a bathochromic shift in dye absorption spectra that indicates dye–surfactant interaction.     

Isolation of a superfamily of candidate disease-resistance genes in soybean based on a conserved nucleotide-binding site

The tobacco N and Arabidopsis RPS2 genes, among several recently cloned disease-resistance genes, share highly conserved structure, a nucleotide-binding site (NBS). Using degenerate oligonucleotide primers for the NBS region of N and RPS2, we have amplified and cloned the NBS sequences from soybean. Each of these PCR-derived NBS clones detected low-or moderate-copy soybean DNA sequences and belongs to 1 of 11 different classes. Sequence analysis showed that all PCR clones encode three motifs (P-loop, kinase-2, and kinase-3a) of NBS nearly identical to those in N and RPS2. The intervening region between P-loop and kinase-3a of the 11 classes has high (26% average) amino acid sequence similarity to the N gene although not as high (19% average) to RPS2. These 11 classes represent a superfamily of NBS-containing soybean genes that are homologous to N and RPS2. Each class or subfamily was assessed for its positional association with known soybean disease-resistance genes through near-isogenic line assays, followed by linkage analysis in F2 populations using restriction fragment length polymorphisms. Five of the 11 subfamilies have thus far been mapped to the vicinity of known soybean genes for resistance to potyviruses (Rsv1 and Rpv), Phytophthora root rot (Rps1, Rps2, and Rps3), and powdery mildew (rmd). The conserved N- or RPS2-homologous NBS sequences and their positional associations with mapped soybean-resistance genes suggest that a number of the soybean disease-resistance genes may belong to this superfamily. The candidate subfamilies of NBS-containing genes identified by genetic mapping should greatly facilitate the molecular cloning of disease-resistance genes.     

The impact of dietary oil source and frozen storage on the physical,chemical and sensorial quality of fillets from market-size red hybrid tilapia, Oreochromis sp.

Red hybrid tilapia (Oreochromis sp.) were fed one of four diets containing either fish oil, crude palm oil, palm fatty acid distillates or refined palm olein as the only added oil. Post-harvest fillet quality was then evaluated at 1, 10 and 30 weeks of frozen storage. Dietary oil source did not significantly (p > 0.05) influence the liquid holding capacity and texture of fillets but both these parameters were increased by frozen storage. Fillets from fish fed palm oil-based diets exhibited significantly higher oxidative stability during frozen storage, compared to fish fed the fish oil diet. Dietary oil source and frozen storage had little impact on sensory attributes. Unlike fillet proximate composition, fillet fatty acid composition was significantly affected by both diet and frozen storage. Total n-3 polyunsaturated fatty acids decreased significantly in the fillet lipids of all fish after 30 weeks of frozen storage.     

Application of the concept of a renewable energy based-polygeneration system for sustainable thermal desalination process—A thermodynamics' perspective

Fossil fuel-powered thermal desalination processes have many harmful environmental effects including greenhouse gas (GHG) emissions and high-salinity brine discharge resulting in biological damages, in addition to energy losses because of the high temperatures of the streams leaving the desalination unit. In this study, a solar energy-based polygeneration approach has been proposed to address these issues. In the proposed system, concentrated solar parabolic trough technology is used to drive a multi-stage flash (MSF) desalination unit for production of fresh water. To recover the waste heat carried by the produced clean water, an organic Rankine cycle is integrated to produce electricity. In addition, to recover the waste heat carried by brine, an absorption cooling system is employed to provide cooling. In order to mitigate the effects of high-salinity brine, a pressure retarded osmosis (PRO) unit is installed, which reduces the salinity of the discharge and produces additional electrical energy. To ensure stable nighttime operations, a thermal energy storage (TES) system is also added to the system. A comprehensive thermodynamic analysis is conducted through mass, energy, and entropy, as well as exergy balances along with energetic and exergetic efficiencies to assess the overall performance of the system. The attained results show that at reference conditions with an overall parabolic trough collectors (PTCs) area of 100 000 m², the system produces 583.3 kW of electricity, approximately 4284 kW of cooling, and 1140 m³ of freshwater daily. Furthermore, the effects of changing operational conditions on the overall performance of the system are investigated. At design conditions, the overall energetic and exergetic efficiencies of the system are found to be 34.54% and 14.55%, respectively.     

Quantitative trace element analysis of individual fly ash particles by means of X-ray microfluorescence

A new quantification procedure was developed for the evaluation of X-ray microfluorescence (XRF) data sets obtained from individual particles, based on iterative Monte Carlo (MC) simulation. Combined with the high sensitivity of synchrotron radiation-induced XRF spectroscopy, the method was used to obtain quantitative information down to trace-level concentrations from micrometer-sized particulate matter. The detailed XRF simulation model was validated by comparison of calculated and experimental XRF spectra obtained for glass microsphere standards, resulting in uncertainties in the range of 3-10% for the calculated elemental sensitivities. The simulation model was applied for the quantitative analysis of X-ray tube and synchrotron radiation-induced scanning micro-XRF spectra of individual coal and wood fly ash particles originating from different Hungarian power plants. By measuring the same particles by both methods the major, minor, and trace element compositions of the particles were determined. The uncertainty of the MC based quantitative analysis scheme is estimated to be in the range of 5-30%.     

Cadmium and zinc concentrations in drinking water supplies of Dhaka City, Bangladesh

The cadmium concentration in different drinking water supplies of Dhaka City is reported. In this study, cadmium was extracted from water into chloroform after chelation with sodium diethyldithiocarbamate and then back extracted into water for determination by atomic absorption spectrophotometry (AAS). The concentration of cadmium in source water is below the detection limit (51 micrograms l-1) and that in supply water (tap water) and tube-well water ranges from 1.03 to 1.58 and 1.71 to 2.24 ppb, respectively. The corresponding zinc content ranges from 0.013 to 0.30, 0.018 to 3.8 and 0.042 to 0.37 ppm. The implications of these findings are discussed.     

Chitosan incorporation for antibacterial property improvement of jute-cotton blended denim fabric

Abstract

Jute-cotton blended denim is a new diversified product for the fashion and clothing sector. Chitosan was incorporated in this blend in order to improve its antimicrobial property. The incorporation of chitosan to the blended apparel was confirmed by Fourier transform infrared spectroscopy. Two microorganisms were used to create individual bacterial medium; one is the gram-positive Staphylococcus aureus and the other is the gram-negative Escherichia coli. Qualitative and quantitative assessments were carried out to evaluate antimicrobial property of chitosan, where the results appeared in favour of chitosan’s significant efficacy as an antimicrobial agent against both before-mentioned microorganisms. Because of low cost, easy application techniques and eco-friendly strategy; the success of this research will boost confidence of clothing product developers and manufacturers to use this blend as a fashionable fabric-material irrespective of climatic areas, gender or ages, that will vastly help to flourish massive scale business of major jute producing countries like Bangladesh and India.     

Mixed Micellization and Interfacial Properties of Ionic Liquid‐Type Imidazolium Gemini Surfactant with Amphiphilic Drug Amitriptyline Hydrochloride and its Thermodynamics

The thermodynamics of mixed micellization of amitriptyline hydrochloride (AMT) with ionic liquid‐type imidazolium gemini surfactant ([C₁₀‐4‐C₁₀im] Br₂), was investigated at different mole fractions and temperatures by surface tension measurements. The deviation of the critical micelle concentration (CMC) from the ideal critical micelle concentration (CMC * ), micellar mole fraction () from ideal micellar mole fraction (), the values of interaction parameter () and activity coefficients () (for both mixed micelles and mixed monolayer) explained the non‐ideal behavior (i.e., synergistic behavior) of binary mixtures. The excess free energy (?G_ex) for the AMT‐[C₁₀‐4‐C₁₀im] Br₂ binary mixtures explained the mixed micelles stability in comparison to micelles of [C₁₀‐4‐C₁₀im] Br₂ and pure AMT. Interfacial parameters, i.e., Gibbs surface excess (), minimum head group area at air/water interface (), free energy of micellization (), and standard Gibbs energy of adsorption (?G_ads^o) were also evaluated for the systems. The standard entropy of adsorption (?S_ads^o) was found higher than the standard entropy of micellization (?S_m^o) at all mole fractions of AMT (α₁).