Size-dependent adsorption and conformational changes induced in bovine serum albumin (BSA) on exposure to titanium dioxide (TiO2) nanoparticles

In this study, TiO₂ nanoparticles (NPs) of different sizes were synthesized using sol gel method and calcined at different temperatures ranging from 200 to 700°C. The specific surface area of TiO₂ was found to decrease with the increase in calcination temperature. It was observed that adsorption of bovine serum albumin (BSA) on TiO₂ NPs obeyed the Freundlich adsorption isotherm, and the isotherm parameters were calculated from equilibrium adsorption batch experiments. The kinetics of adsorption was best fitted by pseudo-first-order kinetic model. The effect of particle dosage on BSA adsorption was also studied and it was observed that the adsorption increased with the increase in particle dosage and decrease in particle size. The conformational changes of BSA on exposure to TiO₂ NPs of various sizes were investigated using circular dichroism spectropolarimetry. The results suggested that BSA underwent a distortion in the secondary structure which was quantified by the percent α-helicity. A size-dependent distortion was observed. The α-helix content changed from 32.3% for pure BSA to 21.9% when exposed to NPs calcined at 200°C (350 mg/L) and to 28.4% for NPs calcined at 700°C at the same concentration.     

Borosilicate glasses modified with organic ligands: a new selective approach for the removal of uranyl ion

Barium borosilicate glass was found to have high uptake capacity for many cations. To improve its selectivity, surface modification was carried out. In order to make the glass selective towards uranyl ion, organic ligands like tri-n-octylphosphine oxide (TOPO) and 8-hydroxy quinoline (Oxine) were used. It was observed that the surface modification resulted in the change in uptake property of the glass. The uptake process was faster and within 5 h, 90% of the uranyl ion could be taken up from a 0.01 mM solution. With use of the modified barium borosilicate glass and EDTA as masking agent, uranyl ion could be selectively removed from mixtures of cations.     

Luminescence properties of SnO2 nanoparticles dispersed in Eu3+ doped SiO2 matrix

SnO2 nanoparticles dispersed in Eu3+ doped silica (SnO2-SiO2:Eu3+) were prepared at a low temperature (185 degrees C) in ethylene glycol medium. Transmission electron microscopy studies on as-prepared samples have established that SnO2 nanoparticles having size of 4.6 nm are uniformly covered by the SiO2 matrix. Significant extent of exciton mediated energy transfer between SnO2 and Eu3+ ions in heat treated SnO2-SiO2:Eu3+ samples has been attributed to the diffusion of Eu3+ ions from the SiO2 matrix to the near vicinity of SnO2 nanoparticles and its incorporation in the SnO2 matrix. On the other hand, very weak energy transfer exists for SnO2:Eu3+ nanoparticles heated at different temperatures due to the phase segregation of Eu3+ ions from the matrix.     

Extending the notion of quality from physical metrology to information and sustainability

In this paper we intend to demonstrate the need for extending the notion of quality from the physical domain to information and, more comprehensively, to sustainability. In physical metrology there are well established principles such as fundamental units, precision, accuracy, traceability and uncertainty. In order to understand and define quality for information and sustainability we need to develop metrological concepts similar to those of physical metrology. Research efforts related to information quality (IQ) are scattered. IQ is primarily defined in terms of several characteristics (dimensions) which lack consensus definitions and are sometimes subjective. However, the notion of IQ is currently in practice and has provided some useful insights towards defining formal approaches to IQ. In order to extend the notion of quality to sustainability we need, as in the case of information, a well defined metrology similar to physical metrology. Sustainability is currently getting attention in many areas of human endeavor. One proposal is to measure sustainability in terms of a triple bottom line, namely social, economical and environmental aspects of human endeavor. Sustainability metrics are continuously evolving and their clear definition is fundamental to the understanding of the notion of sustainability quality. As an example we consider evaluation of carbon footprint, as a metric towards sustainability, for manufacturing a simple turned part. After analyzing the current literature, we identify the following needs for characterizing the notion of sustainability quality: (a) standardized terminology of terms and concepts, (b) metrics and metrology, (c) harmonization and extension of standards, (d) conformance testbeds for standards and (e) development of information models that support sustainability.     

Application of emerging technologies to control Salmonella in foods: A review

Salmonella is one of the major causes of foodborne illnesses in United States and many other parts of the world. The ubiquitous nature of the organisms and innumerous serotypes present in various foods make it challenging for researchers to strive for its elimination. In the past decade, various novel technologies have emerged with great potential to inactivate Salmonella and other foodborne pathogens. This review paper aims to compile research works reported in the recent past with emphasis on the use of emerging technologies such as, ozone, ultraviolet light, ultrasound, electrolyzed oxidized water, high pressure carbon dioxide, and bacteriophage. Other novel technologies like high pressure processing, pulsed electric field processing and irradiation were not covered considering their vastness of literature and availability of published reviews. Many of these emerging technologies have already reached commercial adoption in specific applications and many others are very promising. Development of suitable equipment, especially to make continuous processing feasible for a variety of foods and standardizing the process parameters for easy regulatory approval will pave the way for improved food quality and safety.     

Novel hybrid SVM-TLBO forecasting model incorporating dimensionality reduction techniques

In this paper, we present a highly accurate forecasting method that supports improved investment decisions. The proposed method extends the novel hybrid SVM-TLBO model consisting of a support vector machine (SVM) and a teaching-learning-based optimization (TLBO) method that determines the optimal SVM parameters, by combining it with dimensional reduction techniques (DR-SVM-TLBO). The dimension reduction techniques (feature extraction approach) extract critical, non-collinear, relevant, and de-noised information from the input variables (features), and reduce the time complexity. We investigated three different feature extraction techniques: principal component analysis, kernel principal component analysis, and independent component analysis. The feasibility and effectiveness of this proposed ensemble model were examined using a case study, predicting the daily closing prices of the COMDEX commodity futures index traded in the Multi Commodity Exchange of India Limited. In this study, we assessed the performance of the new ensemble model with the three feature extraction techniques, using different performance metrics and statistical measures. We compared our results with results from a standard SVM model and an SVM-TLBO hybrid model. Our experimental results show that the new ensemble model is viable and effective, and provides better predictions. This proposed model can provide technical support for better financial investment decisions and can be used as an alternative model for forecasting tasks that require more accurate predictions.     

Biogenic synthesis of silver nanoparticles from Cassia fistula (Linn.): In vitro assessment of their antioxidant,antimicrobial and cytotoxic activities

The present study reports on biogenic‐synthesised silver nanoparticles (AgNPs) derived by treating Ag ions with an extract of Cassia fistula leaf, a popular Indian medicinal plant found in natural habitation. The progress of biogenic synthesis was monitored time to time using a ultraviolet–visible spectroscopy. The effect of phytochemicals present in C. fistula including flavonoids, tannins, phenolic compounds and alkaloids on the homogeneous growth of AgNPs was investigated by Fourier‐transform infrared spectroscopy. The dynamic light scattering studies have revealed an average size and surface Zeta potential of the NPs as, −39.5 nm and −21.6 mV, respectively. The potential antibacterial and antifungal activities of the AgNPs were evaluated against Bacillus subtilis, Staphylococcus aureus, Candida kruseii and Trichophyton mentagrophytes. Moreover, their strong antioxidant capability was determined by radical scavenging methods (1,1‐diphenyl‐2‐picryl‐hydrazil assay). Furthermore, the AgNPs displayed an effective cytotoxicity against A‐431 skin cancer cell line by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide (MTT) assay, with the inhibitory concentration (IC₅₀) predicted as, 92.2 ± 1.2 μg/ml. The biogenically derived AgNPs could find immense scope as antimicrobial, antioxidant and anticancer agents apart from their potential use in chemical sensors and translational medicine.Inspec keywords: antibacterial activity, biomedical materials, cancer, cellular biophysics, electrokinetic effects, Fourier transform infrared spectra, light scattering, microorganisms, nanomedicine, nanoparticles, silver, skin, spectrochemical analysis, toxicology, ultraviolet spectra, visible spectraOther keywords: Ag, voltage ‐21.6 mV, size ‐39.5 nm, A‐431 skin cancer cell line, cytotoxicity, 1,1‐diphenyl‐2‐picryl‐hydrazil assay, radical scavenging methods, Trichophyton mentagrophytes, Candida kruseii, Staphylococcus aureus, Bacillus subtilis, surface zeta potential, dynamic light scattering studies, Fourier‐transform infrared spectroscopy, alkaloids, phenolic compounds, tannins, flavonoids, phytochemical effect, ultraviolet‐visible spectroscopy, Cassia fistula leaf extract, biogenic‐synthesised silver nanoparticles, cytotoxic activities, antimicrobial activities, antioxidant activities     

Structural and Thermophysical Properties of (PbO)0.5(SiO2)0.5 Glasses: Effect of SnO2 Incorporation

¹¹⁹Sn and ²⁹Si solid-state nuclear magnetic resonance studies on lead silicate glasses containing different amounts of SnO₂ confirmed that tin exists in the glass as distorted SnO₆ polyhedra and there is no direct interaction between tin and silicon structural units. Transmission electron microscopic studies have established that tin structural units are uniformly distributed in the glass. Significant changes in the values of glass transition temperature, microhardness, and thermal expansion coefficient with SnO₂ incorporation into the glass have been attributed to the increased rigidity of the glass network brought about by the replacement of weaker Pb–O linkages with stronger Sn–O linkages.     

Comparative study of hydrophilic modification of polyacrylonitrile membranes by nitrogen and carbon dioxide RF plasma

Low temperature plasma treatment using radio frequency (RF) discharge of nitrogen and carbon dioxide gases was employed to enhance hydrophilicity of the polyacrylonitrile copolymer membrane surface. Influence of various plasma operating conditions, namely, power and exposure time on improvement of surface energy, permeability, and hydrophilicity of the membrane was investigated. Surface energy of RF nitrogen plasma‐treated membrane (70 W, 8 min) was enhanced by 70%. Surface etching due to plasma treatment was confirmed by weight loss of the treated membranes. About 78% increase in average pore size was obtained using RF carbon dioxide plasma treatment due to surface etching. Hydrophilicity of nitrogen plasma modified membrane was enhanced by 32% and it was maintained up to 100 days. The pore enlargement due to plasma etching is more effective compared to surface energy in enhancing permeability (70%) of RF carbon dioxide modified (70 W, 6 min) membrane throughout the aging period. The permeability of nitrogen RF plasma‐treated membrane is affected by surface energy and pore enlargement for initial 20 days of aging. After that, the permeability of treated PAN only depends on pore enlargement due to plasma etching. The nitrogen plasma modified surfaces appear to retain their functionality better than carbon dioxide plasma‐treated samples. Oxygen and nitrogen functional groups were identified to be responsible for surface hydrophilicity. POLYM. ENG. SCI., 59:2148–2158, 2019. © 2019 Society of Plastics Engineers     

Traditional fermented foods and beverages of Darjeeling and Sikkim–a review

The various ethnic groups of the Darjeeling district of West Bengal and Sikkim consume a variety of fermented foods including kinema (based on soya beans),gundruk (Brassica campestris leaves),sinki (radish, Raphanus sativus), mesu (bamboo shoots),churpi (milk),shel rod (rice preparation) and jnards (beers). These have not previously been investigated, and their method of preparation and consumption are reported here. The flora of murcha, the starter culture of jnards, contains mainly Pediococcus, yeasts belonging to the genera Saccharomycopsis, Pichia and Saccharomyces and the moulds Rhizopus and Mucor.