A comparative study of the gas sensing behavior of nanostructured nickel ferrite synthesized by hydrothermal and reverse micelle techniques

A comparative study of gas sensing behavior of nanocrystalline nickel ferrite synthesized by micro-emulsion and hydrothermal method to liquefied petroleum gas (LPG) is presented. Nanocrystalline nickel ferrite synthesized by hydrothermal method indicated higher electrical conductivity and gas sensitivity at low operating temperature compared to nanocrystalline nickel ferrite synthesized by reverse micelle technique. This difference in the gas sensing behavior can be attributed to the presence of more oxygen vacancies (i.e. non-stoichiometry) in the hydrothermally synthesized nickel ferrite. Incorporation of palladium had a catalytic effect and the operating temperature was significantly reduced in both the samples. The higher operating temperature of the reverse micelle nickel ferrite material makes the sensor response speed faster (∼10 s) compared to the hydrothermally synthesized material (∼1 min).     

Genome-Wide Identification and Characterization of PIN-FORMED (PIN) Gene Family Reveals Role in Developmental and Various Stress Conditions in Triticum aestivum L.

PIN-FORMED (PIN) genes play a crucial role in regulating polar auxin distribution in diverse developmental processes, including tropic responses, embryogenesis, tissue differentiation, and organogenesis. However, the role of PIN-mediated auxin transport in various plant species is poorly understood. Currently, no information is available about this gene family in wheat (Triticum aestivum L.). In the present investigation, we identified the PIN gene family in wheat to understand the evolution of PIN-mediated auxin transport and its role in various developmental processes and under different biotic and abiotic stress conditions. In this study, we performed genome-wide analysis of the PIN gene family in common wheat and identified 44 TaPIN genes through a homology search, further characterizing them to understand their structure, function, and distribution across various tissues. Phylogenetic analyses led to the classification of TaPIN genes into seven different groups, providing evidence of an evolutionary relationship with Arabidopsis thaliana and Oryza sativa. A gene exon/intron structure analysis showed a distinct evolutionary path and predicted the possible gene duplication events. Further, the physical and biochemical properties, conserved motifs, chromosomal, subcellular localization, transmembrane domains, and three-dimensional (3D) structure were also examined using various computational approaches. Cis-elements analysis of TaPIN genes showed that TaPIN promoters consist of phytohormone, plant growth and development, and stress-related cis-elements. In addition, expression profile analysis also revealed that the expression patterns of the TaPIN genes were different in different tissues and developmental stages. Several members of the TaPIN family were induced during biotic and abiotic stress. Moreover, the expression patterns of TaPIN genes were verified by qRT-PCR. The qRT-PCR results also show a similar expression with slight variation. Therefore, the outcome of this study provides basic genomic information on the expression of the TaPIN gene family and will pave the way for dissecting the precise role of TaPINs in plant developmental processes and different stress conditions.     

Microencapsulation of reactive amine by interfacially engineered epoxy microcapsules for smart applications

The most common approach for incorporation of extrinsic self-healing functionality relies on introducing healant-loaded micro-containers in the polymeric formulation. In this context, a healing system based on encapsulated epoxy resin and amine hardener appears to be one of the most economically viable solutions, in view of the chemical as well as mechanical compatibility with the matrix. Encapsulation of epoxy resins has been extensively studied while the high reactivity of the amine hardener renders its encapsulation rather difficult and has been attempted with only modest success. The purpose of the present work is to adopt an interfacial polymerization approach for the preparation of epoxy microcapsules encapsulating a reactive amine hardener (triethylene tetramine). The effects of experimental parameters, including reaction temperature, stirring speed and epoxy/amine concentration ratio on the microcapsule formation were investigated. A polymeric surfactant was used to stabilize the suspension to modulate the particle size distribution of the resultant microcapsules. The highest encapsulation efficiencies were obtained when the reaction medium was maintained at 70 °C under stirring (600 rpm) at epoxy/amine ratio of 10/3.2. The microcapsule dimensions and core content could be tailored, following this encapsulation approach of interfacial polymerisation. Under optimal conditions, spherical microcapsules with 100% yield and 12% core content were obtained.     

Shape effects of filaments versus spherical particles in flow and drug delivery

Interaction of spherical particles with cells and within animals has been studied extensively, but the effects of shape have received little attention. Here we use highly stable, polymer micelle assemblies known as filomicelles to compare the transport and trafficking of flexible filaments with spheres of similar chemistry. In rodents, filomicelles persisted in the circulation up to one week after intravenous injection. This is about ten times longer than their spherical counterparts and is more persistent than any known synthetic nanoparticle. Under fluid flow conditions, spheres and short filomicelles are taken up by cells more readily than longer filaments because the latter are extended by the flow. Preliminary results further demonstrate that filomicelles can effectively deliver the anticancer drug paclitaxel and shrink human-derived tumours in mice. Although these findings show that long-circulating vehicles need not be nanospheres, they also lend insight into possible shape effects of natural filamentous viruses.     

Solubilization of Phenanthrene and Fluorene in Equimolar Binary Mixtures of Gemini/Conventional Surfactants

abstract This study deals with the enhanced solubilization of polycyclic aromatic hydrocarbons (PAHs) such as phenan-threne (PHE) and fluorene (FLR) in a pure cationic gemini (G6) and three conventiona...     

A Systematic Study of Mixed Surfactant Solutions of a Cationic Ester-Bonded Dimeric Surfactant with Cationic, Anionic and Nonionic Monomeric Surfactants in Aqueous Media

A novel cationic biodegradable dimeric (gemini) surfactant, ethane-1,2-diyl bis(N,N-dimethyl-N-hexadecylammoniumacetoxy) dichloride (16-E2-16), containing an ester-linked spacer was synthesized. Its pure and mixed micellization properties with monomeric surfactants cetyl trimethyl ammonium chloride, cetyl pyridinium chloride, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, cetyl alcohol ethoxylate (20EO) and tert-octylphenol ethoxylate (9.5EO) were investigated by surface tension measurements at 30 °C. The critical micelle concentration (CMC) of 16-E2-16 is well below that of cetyl trimethyl ammonium chloride containing the same number of carbon atoms in the hydrophobic tail per polar head. At different mole fractions of the gemini surfactant, the CMCs of the gemini-conventional binary mixtures were determined and were found to be less than the ideal CMC values in all the cases indicating synergistic interactions. Aggregation number and Stern–Volmer constant, obtained by the fluorescence quenching technique, also support the synergistic behavior of the surfactant systems.     

Understanding the role of internal microstructure in capsule‐based healing of polymeric composites

The efficacy of microcapsules possessing varied internal microstructure toward introducing extrinsic self‐healing functionality in epoxy has been compared. Unsaturated polyester was encapsulated in microcapsules by adopting different methodologies. Microcapsules formed using dispersion polymerization exhibited “reservoir” microstructure while solvent evaporation led to the formation of “monolithic” microcapsules. Theoretical model was developed to predict the amount of healant released in the event of microcapsule rupture, which clearly highlighted the benefits associated with reservoir type microcapsules, especially at lower core contents. At larger core contents (≥50% vol/vol), all the micro‐droplets within the monolithic structure coalesced to form a healant reservoir. Self‐healing composites were prepared by introducing both types of microcapsules in an epoxy matrix and the healing efficiency was quantified. In line with the theoretical predictions, reservoir type microcapsules led to much higher healing efficiencies in comparison to monolithic microcapsules. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45471.     

Preparation and characterization of barium stannate: application as a liquefied petroleum gas sensor†

Barium stannate, BaSnO₃, an n-type semiconducting oxide with cubic perovskite structure, has been prepared by the thermal decomposition of barium carbonate (BaCO₃) and tin tetrahydroxide (Sn(OH)₄). The material was characterized by various physical techniques such as differential thermal analysis (DTA/TG), X-ray diffraction (XRD), BET surface area, Fourier transform infra-red (FT-IR) spectroscopy and scanning electron microscopy (SEM). Of its several applications, this material has proven to be one of the successful candidates for the detection of liquefied petroleum gas (LPG). The sensor has a very good selectivity to detect LPG in comparison to other reducing gases, like carbon monoxide and methane.     

Study of electrochemically grown copper indium diselenide (CIS) thin films for photovoltaic applications

CIS thin films have been grown electrochemically from an aqueous electrolyte at room temperature on fluorine doped tin oxide coated glass substrate at different deposition potentials ranging from ?0.7 to ?1.0 V versus Ag/AgCl reference electrode. Cyclic voltammetry was studied at slow scan rate to optimize the deposition potential. The thin film samples were selenized in a tubular furnace at 400 °C for 20 min. X-ray diffraction and Raman analysis was used to study the structural properties. Optical absorption, scanning electron microscopy and energy dispersive X-ray analysis (EDAX) have been used to investigate the band-gap, surface morphology and compositional analysis. Electrical properties were studied with the help of current–voltage measurements. Conductivity type for CIS thin films was studied by using photo-electrochemical study. The prominent reflections (112), (204/220) and (312/116) of tetragonal chalcopyrite CIS have been revealed for all as-grown and selenized samples. The energy band gap of the selenized CIS thin film deposited at various deposition potentials was found to be ~1.03 to 1.24 eV. Granular, uniform and void free surface was observed in as-prepared sample, while large clusters were noticed in selenized samples. EDAX results reveal that the stoichiometric CIS thin film are deposited ?0.8 V, however, Cu-rich and In-rich CIS layers were grown at lower and higher cathodic deposition potentials, deviated from ?0.8 V. The values ideality factor (η) calculated from I–V measurements were found to be decreased upon selenization. The Raman spectra of stoichiometric CIS thin film shows dominant A1 mode with spectral features sensitive to the microcrystalline quality of the layers. A ordered defect compound layer and secondary phases of CuSe are observed in In-rich and Cu-rich CIS layers, respectively.