A comparative study on free and bound phenolic acid content and their antioxidant activity in bran of rice (Oryza sativa L.) cultivars of Eastern Himalayan range

In our study, seven most prevailing but unexplored indigenous rice cultivars of northeast India, situated in the Eastern Himalayan Range, were investigated for their phenolic acid profile, total phenolic content (TPC) and antioxidant capacities in free and bound phenolic extracts of their bran. HPLC studies showed the presence of ferulic, p‐coumaric, sinapic, caffeic, chlorogenic and vanillic acids, with ferulic and p‐coumaric acids being the dominant phenolic acids in the bound form. The lower EC₅₀ values of the bound extracts than the free extracts suggested the better radical scavenging activity of the bound extracts. Significant correlations were observed between TPC and phenolic acid content (HPLC‐DAD) of bound extracts, and between Trolox equivalents antioxidant capacity (TEAC) and phenolic acid content (HPLC‐DAD) of both free and bound extracts. The findings suggest that phenolic acids in the rice cultivars investigated were exclusively present in bound form and contribute significantly towards their antioxidant capacity.     

Modeling methyl methacrylate free radical polymerization: Reaction in hydrophobic nanopores

Free radical polymerization of methyl methacrylate in nanopores has been shown to result in a decrease in the time for the onset of autoacceleration. In this work, we simplify our previous kinetic model of nanoconfined methyl methacrylate polymerization, which was based on the work of Verros and coworkers, and incorporate diffusion effects into the model using the Doolittle free volume theory. The simplified model well describes the experimental calorimetric conversion versus time data for isothermal bulk methyl methacrylate polymerization, capturing autoacceleration and the dependence of the limiting conversion on temperature. In order to model the reaction in nanopores, we assume that the diffusion coefficient scales with molecular size to the ?3 power and with nanopore diameter to the 1.3 power. Experimental calorimetric conversion versus time data for polymerization in hydrophobic nanopores are well captured by the model, including the decrease in the time to reach autoacceleration with decreasing pore size. The scaling assumed is consistent with that predicted using molecular simulations for good solvent conditions by Avramova and Milchev and by Cui, Ding, and Chen. According to the fit of the experimental data, chain diffusivity is 20–50% of the bulk value in 13 nm-diameter pores.     

Microbiology of pond ecosystems in rural Bangladesh: its public health implications

In rural Bangladesh various components of four ponds, including aquatic plants, snails, water, oysters, and sediment were studied for faecal contamination for three years, from July 1994, to June 1997. Faecal coliform counts ranged from 2.80–5.45, 2.95–5.64, 1.49–2.05, 2.51–4.60 and 1.30–3.15 log₁₀cfu/gm or ml in plant, snail, water, oyster and sediment samples respectively during the study period. Snail and sediment samples showed highest and lowest counts, respectively. All components of the studied ponds included in this study yielded coliform counts higher than the accepted limit for potability and domestic use, as recommended by the WHO. Therefore these ponds have a high potential for transmission of diarrhoeal and other water‐borne diseases.     

Synthesis and characterization of magnetic beads containing aminated fibrous surfaces for removal of Reactive Green 19 dye: kinetics and thermodynamic parameters

BACKGROUND: Poly(HEMA‐co‐MMA) beads were prepared from 2‐hydroxyethyl‐methacrylate (HEMA) and methylmethacrylate (MMA) in the presence of FeCl₃. Thermal co‐precipitation of Fe(III) ions containing beads with Fe(II) ions was carried out under alkaline conditions. The magnetic beads were grafted with poly(glycidylmethacrylate; p(GMA)), and the epoxy groups of the grafted p(GMA) brushes were converted into amino groups by reaction with ammonia. RESULTS: The magnetic beads were characterized by surface area measurement, electron spin resonance (ESR), Mössbauer spectroscopy and scanning electron microscopy (SEM). The maximum adsorption of Reactive Green‐19 (RG‐19) dye on the p(GMA) grafted and amine modified magnetic beads was around pH 3.0. The adsorption capacity of magnetic beads was 84.6 mg dye g^?1. The effects of adsorbent dosage, ionic strength and temperature have also been reported. Batch kinetic sorption experiments showed that a pseudo‐second‐order rate kinetic model was applicable. CONCLUSION: The p(GMA) grafted and amine modified magnetic beads (adsorbent) were expected to have the advantage of mobility of the grafted chains in the removal of acidic dyes from aqueous solutions. The magnetic beads have potential as an adsorbent for removal of pollutants under various experimental conditions without significant reduction in their initial adsorption capacity. Copyright © 2011 Society of Chemical Industry     

Comparative Pharmacognostic Evaluation and HPTLC Analysis of Petals of Spiny and Non-Spiny Safflower Cultivars

To establish the identity and quality of safflower petals used as herbal tea, four spiny and non-spiny cultivars (APRR3, TSF-1, NARI-NH-01, and NARI-06) were analyzed for various pharmacognostic characters, toxic metals (As, Pb, Hg, Cr, Cd by atomic absorption spectroscopy), pesticide residue (GC-ECD/PFPD), and flavonoid constituents, like quercetin, quercetin-3-O-rutinoside, and kaempferol, by high performance thin layer chromatography. Arsenic and lead were found to be absent in the decoction of all varieties. Although mercury and chromium were detected in standard acceptable levels, cadmium was exceeding the limit except in APRR3 (0.3 mg/kg). While none of the samples contained pesticide residue and saponins, presence of tannins (19–25%), bitterness principle (1257–2200 units/g), mucilaginous substances (0.93–2.83 mL/g), and volatile matter (4–16%) were observed and estimated in all varieties. Microscopic examination of NARI-06 and APRR3 petals explored similar features having slightly thick cylindrical style with dense spikes and corolla tube with five slightly thick ridges possessing ribbon like outgrowths. High performance thin layer chromatography analysis revealed APRR3 to possess higher amount of quercetin (116.6 ng/g), quercetin-3-O-rutinoside (189.7 ng/g), and kaempferol (185.07 ng/g). Thus, the spiny APRR3 safflower petals encompassing anti-oxidative flavonoids and complying heavy metals test, was identified as a safe variety for human consumption.     

Spatial and temporal trends in nitrate concentrations in the River Derwent, North Yorkshire, and its need for NVZ status

Long-term spatial and temporal variations in nitrate-N concentrations along the River Derwent have been examined using Environment Agency data to investigate the relative importance of impacts of atmospheric N deposition, land use, and changes in management. Where moorland and rough grazing dominate upstream of Forge Valley and Malton, over the 20 years since 1988 mean nitrate-N concentrations were initially increasing significantly, but are now levelling off, with peaks at ca. 4.5 mg N l⁻¹. As expected in a catchment in a nitrate vulnerable zone (NVZ), more agricultural land use increases mean nitrate concentrations and the occurrence of distinct winter maxima, though the latter have become markedly less pronounced since 2001. It is suggested that this improvement is a combined effect of imposition of NVZ designation in the lower reaches in 2002, animal number declines associated with the Foot & Mouth outbreak in the region in 2001, and the impact of farmers' responses to increasing fertilizer prices and to beneficial pollutant mineral N inputs from the atmosphere. Minima in nitrate-N concentrations in summer have become much less pronounced over the past decade and are typically ca. 60% higher in concentration than a decade earlier. This probably is attributable to the effects of pollutant-N leaching to depths in soil below the rooting zone when near surface biotic uptake is low in winter. The resultant N mineralization in summer enhances summer nitrate leaching. The Derwent is a relatively clean river; however, its entire catchment was designated justifiably as a NVZ in January 2009, apparently based upon a projected 95 percentile nitrate-N concentration > 11.29 mg l^− 1 for 2010 based upon forward projection of data from 1990 to 2004 for Derwent Bridge. A survey of water quality in March 2009 showed that some agricultural areas are still making a significant contribution to the total nitrate level well downstream, at the point responsible for implementation of NVZ status. At 3 of the 29 sites sampled, nitrate concentration exceeded 60 mg l^− 1.     

Physical and optical properties of Co2+, Ni2+ doped 20ZnO + xLi2O + (30 − x)K2O + 50B2O3 (5 ≤ x ≤ 25) glasses: Observation of mixed alkali effect

Co²⁺ and Ni²⁺ ions doped 20ZnO + xLi₂O + (30 ? x) K₂O + 50B₂O₃ (5 ≤ x ≤ 25) mol% glasses are prepared using melt quenching technique. Structural changes of the prepared glasses by addition of transition metal oxides, CoO and NiO are investigated by UV–vis–NIR, FT-IR spectroscopy and XRD. The XRD pattern indicates the amorphous nature of prepared glasses. FT-IR measurements of the all glasses revealed that the network structure of the glasses are mainly based on BO₃ and BO₄ units placed in different structural groups in which the BO₃ units being dominant. The optical absorption spectra suggest the site symmetry of Co²⁺ and Ni²⁺ ions in the glasses are near octahedral. Crystal field and inter-electronic repulsion parameters are also evaluated. The optical band gap and Urbach energies exhibited the mixed alkali effect. Various physical parameters such as density, refractive index, optical dielectric constant, polaron radius, electronic polarizability and inter-ionic distance are also determined.     

Protein-Assembled Nanocrystal-Based Vertical Flash Memory Devices with Al<Subscript>2</Subscript>O<Subscript>3</Subscript> Integration

This work presents vertical flash memory devices with protein-assembled PbSe nanocrystals as a floating gate and Al₂O₃ as a control oxide. The advantage of a vertical structure is that it improves cell density. Protein assembly improves uniformity of nanocrystals, which reduces threshold voltage variation among devices. The introduction of Al₂O₃ as a control oxide provided lower voltage/faster operation and hence less power consumption compared with the devices fabricated with SiO₂. The integration of Al₂O₃ appeared to be compatible with the protein assembly approach. In conclusion, Al₂O₃ has the potential to become the high-k control oxide due to its relatively high electron/hole barrier heights, and high permittivity.     

Emulsion Liquid Membrane Pertraction of Zinc and Copper: Analysis of Emulsion Formation using Computational Fluid Dynamics

This work reports on a study of batch extraction of metal ions (copper and zinc) from dilute aqueous solutions as well as recovery of copper from electroplating waste water by the emulsion liquid membrane (ELM) technique. Several experiments were conducted to assess the effect of membrane composition on metal recovery. The effect of surfactant concentration, carrier concentration, and emulsification time on the emulsion stability has been reported. The velocity profile and flow model of the two‐phase mixing system during the preparation of the emulsion was generated using computational fluid dynamics (CFD). The batch extraction was carried out under various experimental conditions, such as agitation speed, M/E ratio, solute concentration in the feed phase, and carrier concentration in the membrane phase on the percentage recovery of zinc and copper ions in their respective feed streams. The operating parameters were optimized for maximum recovery. A comparison on the percentage recovery was made between synthetic solution and electroplating effluent containing copper ions.     

Influence of Radiation Processing of Cooked Beef Sausage on Its Lipids

The effect of gamma irradiation on fatty acid composition and lipid oxidation in emulsion-type cooked beef sausages was investigated. Vacuum-packaged sausages were irradiated at 2, 4, 6 and 8 kGy and stored at 4 °C for 4 weeks. Samples were analyzed for fatty acid composition at 0 and 4 weeks and lipid oxidation after 0, 1, 2, 3 and 4 weeks of storage. Irradiation reduced the content of oleic acid and linoleic acid, and the effect was intensified during storage. Elaidic acid content increased at doses of 6 and 8 kGy. The results indicated that irradiation at 6 and 8 kGy increased lipid oxidation, measured as the thiobarbituric acid reactive substances value. Based on the results, cooked beef sausages could be irradiated at 2 and 4 kGy without affecting the molecular structure of lipids.