Ru(III)-catalysed oxidation of some N-heterocycles by chloramine-T in hydrochloric acid medium: A kinetic and mechanistic study

The kinetics of the ruthenium(III) chloride (Ru(III))-catalysed oxidation of five N-heterocycles (S) viz. imidazole (IzlH), benzimidazole (BzlH), 2-hydroxybenzimidazole (2-HyBzlH), 2-aminobenzimidazole (2-AmBzlH) and 2-phenylbenzimidazole (2-PhBzlH) by sodium-N-chloro-p-toluenesulfonamide (chloramine-T; CAT) in the presence of HCl has been studied at 313 K. The oxidation reaction follows the identical kinetics for all the five N-heterocycles and obeys the rate law, rate = k CAT0 S 0 x H+y Ru(III)z, where x, y and z are less than unity. Addition of p-toluenesulfonamide (PTS) retards the reaction rate. Variation of ionic strength of the medium and the addition of halide ions show negligible effect on the rate of the reaction. The rate was found to increase in D2O medium and showed positive dielectric effect. The reaction products are identified. The rates are measured at different temperatures for all substrates and the composite activation parameters have been computed from the Arrhenius plots. From enthalpy-entropy relationships and Exner correlations, the calculated isokinetic temperature (β) of 392 K is much higher than the experimental temperature (313 K), indicating that, the rate has been under enthalpy control. Relative reactivity of these substrates are in the order: 2-HyBzlH > 2-AmBzlH > BzlH > IzlH > 2-PhBzlH. This trend may be attributed to resonance and inductive effects. Further, the kinetics of Ru(III)-catalysed oxidation of these N-heterocycles have been compared with uncatalysed reactions (in the absence of Ru(III) catalyst) and found that the catalysed reactions are 16-20 times faster. The catalytic constant (KC) was also calculated for each substrate at different temperatures. From the plots of log KC versus 1/T, values of activation parameters with respect to the catalyst have been evaluated. H2O+Cl has been postulated as the reactive oxidizing species. The reaction mechanism and the derived rate law are consistent with the observed experimental results. © 2004 Elsevier B.V. All rights reserved

Food Safety Knowledge, Behavior, and Attitudes of Vendors of Poultry Products Sold at Pennsylvania Farmers\u27 Markets

A needs assessment survey was developed to assess the knowledge and attitudes of poultry vendors at farmers\u27 markets in Pennsylvania, on food safety, regulation, and poultry production. Vendors were administered a 32-question paper survey, in person, during market hours. The results revealed critical vendor practices and identified important vendor knowledge gaps and attitudes on food safety and poultry processing. The data obtained from the study will aid in the development of future farmers\u27 market research, as well as generating training and outreach materials on food safety for vendors selling meat and poultry products at farmers\u27 markets

Diversity and Functions of Chromophores in Insects: A Review

Insects are the most diverse among the animal kingdom. The diversity of insects is ever increasing due to their fast adaptability to the rapidly changing environmental conditions. The physiology of insects plays a vital role in the adaptation and competing adjustments in the nature with other species. The mechanism of vision and the involvement of visual pigments, like chromophores particularly in flies, have proved to be landmarks in the field of research. This has been achieved with the discovery of novel pathways involved in the mechanism of pigment development. However, certain visual pigments and their relationship with various chromophores need to be further elaborated. The role of insect pigments in vision, to identify the hosts, prays, and predators, is also discussed. Many naturally occurring pigments of insect origin are continuously being explored for better prospects and human welfare. The abundant availability of insect species all over the world and the never ending task of exploring their potential at morphological, physiological, evolutionary, and genetic levels have a tremendous potential to explore the subject like entomology

Diversity of Pigments in Insects, Their Synthesis and Economic Value for Various Industries

Pigments play an essential role in imparting colors to the various organs of invertebrates particularly, insects. Genetic evolution and adaptive pigmentation of invertebrates have been studied which depicted that insect colors respond to the climatic changes. The physical, chemical and structural properties of insect pigments are being studied by researchers for years to elucidate their evolutionary aspects of physiology, metabolism, and economic importance for human welfare. Color development in insects varies within the species of different genera. In this state-of-the-art literature review, we discuss the variety of pigments other than visual ones found in different species of insects. The review also highlights the potential benefits or functions of pigments to insects

Structure and Optical Properties of Self-Assembled Multicomponent Plasmonic Nanogels

Multicomponent plasmonic nanogels (PNGs) capable of broadband absorption of light in the 400-700 nm wavelength range were synthesized by the self-assembly of metal nanoparticles with wormlike surfactant micelles. Small angle x-ray scattering and rheological experiments suggest that the nanoparticles bridge micelle fragments to aid the formation a stable gel phase with exceptional color uniformity. Their optical absorbance could be robustly tuned by changing the nanoparticle type (Au/Ag), size, shape, and/or concentration. The PNGs have relatively low viscosity and are thermoreversible. Potential applications to the manufacturing of coatings and interfaces for solar energy harvesting and reconfigurable optical devices can be envisioned

Plasmonic Nanogels with Robustly Tunable Optical Properties

Low viscosity fluids with tunable optical properties can be processed to manufacture thin film and interfaces for molecular detection, light trapping in photovoltaics and reconfigurable optofluidic devices. In this work, self-assembly in wormlike micelle solutions is used to uniformly distribute various metallic nanoparticles to produce stable suspensions with localized, multiple wavelength or broad-band optical properties. Their spectral response can be robustly modified by varying the species, concentration, size and/or shape of the nanoparticles. Structure, rheology and optical properties of these plasmonic nanogels as well as their potential applications to efficient photovoltaics design are discussed

Evaluation of census techniques to estimate the density of slender Loris (Loris lydekkerianus) in Southern India

Reliable estimates of species density are fundamental to planning conservation strategies for any species; further, it is equally crucial to identify the most appropriate technique to estimate animal density. Nocturnal, small-sized animal species are notoriously difficult to census accurately and this issue critically affects their conservation status. We carried out a field study in southern India to estimate the density of slender loris, a small-sized nocturnal primate using line and strip transects. Actual counts of study individuals yielded a density estimate of 1.61 ha–1; density estimate from line transects was 1.08 ha–1; and density estimates varied from 1.06 ha–1 to 0.59 ha–1 in different fixed-width strip transects. We conclude that line and strip transects may typically underestimate densities of cryptic, nocturnal primates

Strengthening Community Engagement Toward Sustainable Local Food Systems

Perspectives of Extension educators relative to local food system (LFS) issues are examined. These educators perceived consumer food safety, viable ag-related businesses, land use planning, farm land preservation, loss of family-owned farms, and access to quality foods as important issues. Extension educators viewed county Extension directors, regional directors, and program advisory boards as the strongest supporters for the local LFS. Lack of program resources to support and carry out LFS programming was identified as a barrier. Significant differences were also found between Extension educators\u27 demographic and program characteristics and important LFS issues