A conducting nanocomposite of acetylene black with preformed poly‐N‐vinylcarbazole crosslinked by anhydrous FeCl3

A conducting nanocomposite of crosslinked poly‐N‐vinylcarbazole (CLPNVC) with nanodimensional acetylene black (AB) was prepared by oxidative crosslinking of preformed PNVC through pendant carbazole moieties in presence of anhydrous FeCl₃ as an oxidant and AB suspension in CHCl₃ medium at 65°C. The incorporation of CLPNVC moieties in the CLPNVC‐AB composite was endorsed by Fourier transform infrared analysis. Scanning electron microscopic analysis showed formation of lumpy aggregates with average sizes in the 130–330 nm ranges. The thermal stability of the CLPNVC‐AB composite was appreciably higher than that of the PNVC‐AB composite. The direct current conductivities of the composites were significantly enhanced relative to that of the PNVC homopolymer (10^?12–10^?16 S/cm) and varied in the range of 10^?4–10^?2 S/cm depending on the amount of AB loading in the CLPNVC‐AB composite. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 819–824, 2006     

The carbon footprint of maize production as affected by nitrogen fertilizer and maize-legume rotations

Studies on the sustainability of crop production systems should consider both the carbon (C) footprint and the crop yield. Knowledge is urgently needed to estimate the C cost of maize (Zea mays L.) production in a continuous monoculture or in rotation with a leguminous crop, the popular rotation system in North America. In this study, we used a 19-year field experiment with maize under different levels of synthetic N treatments in a continuous culture or rotation with forage legume (Alfalfa or red clover; Medicago sativa L./Trifolium pratense L.) or soybean (Glycine max L. Merr) to assess the sustainability of maize production systems by estimating total greenhouse gas (GHG) emissions (kg?CO₂ eq?ha^?1) and the equivalent C cost of yield or C footprint (kg?CO₂ ?eq?kg^?1?grain). High N application increased both total GHG emissions and the C footprint across all the rotation systems. Compared to continuous maize monoculture (MM), maize following forage (alfalfa or red clover; FM) or grain (soybean; SM) legumes was estimated to generate greater total GHG emissions, however both FM and SM had a lower C footprint across all N levels due to increased productivity. When compared to MM treated with 100?kg?N?ha^?1, maize treated with 100?kg?N?ha^?1, following a forage legume resulted in a 5?% increase in total GHG emissions while reducing the C footprint by 17?%. Similarly, in 18 out of the 19-year period, maize treated with 100?kg?N?ha^?1, following soybean (SM) had a minimal effect on total GHG emissions (1?%), but reduced the C footprint by 8?%. Compared to the conventional MM with the 200?kg?N?ha^?1 treatment, FM with the 100?kg?N?ha^?1 treatment had 40?% lower total GHG emissions and 46?% lower C footprint. Maize with 100?kg?N?ha^?1 following soybean had a 42?% lower total GHG emissions and 41?% lower C footprint than MM treated with 200?kg?N?ha^?1. Clearly, there was a trade-off among total GHG emissions, C footprint and yield, and yield and GHG emissions or C footprint not linearly related. Our data indicate that maize production with 100?kg?N?ha^?1 in rotation with forage or grain legumes can maintain high productivity while reducing GHG emissions and the C footprint when compared to a continuous maize cropping system with 200?kg?N?ha^?1.     

Initial rate study on the vapor-phase condensation of aniline to diphenylamine

The vapor-phase condensation of aniline to diphenylamine has been studied in a downflow differential reactor at 370–426°C and under atmospheric pressure using H-151 ALCOA catalyst. An initial rate equation based on the Langmuir-Hinshelwood model, i.e. surface reaction control with a similar dual site mechanism, has been proposed: r_o = (k₁K_A²p_Ao²)/ (1 + K_Ap_Ao)² The effects of different mass transfer resistances, of longitudinal and of radial dispersion have been taken into consideration. The rate constant value at 404°C is 1.488 × 10^?7 (k mol)/ (s) (kg cat) [5.358 × 10^?4 (mol)/ (h) (g cat)] and the activation energy is calculated to be 123.3 kJ/mol [29.45 k cal/mol] in the working temperature range.     

Quantification of organoclay dispersion and lamellar morphology in poly(propylene)-clay nanocomposites with small angle X-ray scattering

Intensity profiles of small angle X-ray scattering (SAXS) curves were analyzed to simultaneously gain quantitative information on nanoclay dispersion as well as lamellar ordering in polypropylene-clay nanocomposites. Different types of PP nanocomposites prepared with PP homopolymer (HPP), random propylene-ethylene copolymer (RCP) and a high impact polypropylene-ethylene propylene rubber (ICP) were analyzed. Various one-dimensional models for stacked structures were applied on Lorentz corrected SAXS spectra to derive long period, thicknesses of alternating high and low electron density layers and their distributions, and the number of stacks for both nanoclay and PP lamellae. We applied a mixed thickness distribution model comprising combined Gaussian and exponential for a simple stack of finite thickness, which was found to explain the experimental data better for both nanoclay tactoids and lamellar stacks, compared to simple Gaussian and exponential thickness distributions. Long period X and number of stacks N were derived as important parameters signifying changes in levels of nanoclay exfoliation in PP. Among the three types of polypropylenes studied, better nanoclay exfoliation was obtained for the high impact ICP grade compared to HPP and RCP. Complete exfoliation of nanoclay was achieved in ICP matrix, employing a masterbatch processing route. Moreover, role of nanoclay as a γ nucleating agent was evident from small and wide angle X-ray analyses, and was seen strongly in RCP. Changes in lamellar structure of PP as a result of nanoclay incorporation, double population consisting of both α and γ polytypes in the nanocomposites from that of a primarily α population in neat polymer matrices, were also analyzed in detail with the mixed thickness distribution model, thereby demonstrating its usefulness.     

Synthesis of Nanocrystalline KTiOPO4 Powder by Chemical Method

Nanocrystalline potassium titanyl phosphate (KTiOPO₄, KTP) powder with average particle size of 25–50 nm has been synthesized from aqueous solution of titanyl chloride through coprecipitation method, using aqueous solution of potassium dihydrogen phosphate and potassium carbonate in the presence of triethanolamine (TEA) as a capping agent. In the presence of tetrapotassium pyrophosphate as a capping agent it produces the particles having average size around 70–80 nm. The same sample with average particle size ∼250 nm has also been synthesized without any capping agent. Initial amorphous phase after precipitation requires heat treatment at 500–550°C for 2 h to generate nanocrystalline powders of KTP. Formation of the KTP phase in the heat-treated samples has been confirmed through X-ray powder diffraction, thermogravimetric and differential thermal analysis, ³¹P Magic angle spinning-nuclear magnetic resonance and Fourier transform infrared spectroscopy studies, and surface area measurements.     

Antioxidative effect of conjugated linolenic acid in diabetic and non-diabetic blood: an in vitro study

The present study examined the in vitro antioxidant activity of conjugated octadecatrienoic fatty acid (9cis, 11 trans, 13 trans-18:3), alpha-eleostearic acid present in karela seed oil (Momordica charantia) at about 55% level. The in vitro antioxidant properties of alpha-eleostearic acid are investigated on oxidative modification of human plasma, low-density lipoprotein (LDL) and erythrocyte membrane lipid. Blood samples are collected from diabetic and non-diabetic (normal) healthy individuals. alpha-eleostearic acid is added at 0.05% and 0.1% concentrations to plasma, LDL and erythrocyte membrane isolated from the respective blood samples and peroxidations are determined against control samples. A significant increase of respective peroxidation levels has been observed in diabetic control blood than the non-diabetic control blood. alpha-eleostearic acid has decreased lipid peroxidation level against control samples in a dose dependent manner. The present findings suggest that CLnA, 9cis, 11trans, 13trans-18:3 is a potentially effective antioxidant that can protect plasma, low density lipoprotein and erythrocyte membrane from oxidation which may be effective in reducing the risk of coronary heart disease in diabetes mellitus.     

Mycobacterium tuberculosis Acetyltransferase Suppresses Oxidative Stress by Inducing Peroxisome Formation in Macrophages

Mycobacterium tuberculosis (Mtb) inhibits host oxidative stress responses facilitating its survival in macrophages; however, the underlying molecular mechanisms are poorly understood. Here, we identified a Mtb acetyltransferase (Rv3034c) as a novel counter actor of macrophage oxidative stress responses by inducing peroxisome formation. An inducible Rv3034c deletion mutant of Mtb failed to induce peroxisome biogenesis, expression of the peroxisomal β-oxidation pathway intermediates (ACOX1, ACAA1, MFP2) in macrophages, resulting in reduced intracellular survival compared to the parental strain. This reduced virulence phenotype was rescued by repletion of Rv3034c. Peroxisome induction depended on the interaction between Rv3034c and the macrophage mannose receptor (MR). Interaction between Rv3034c and MR induced expression of the peroxisomal biogenesis proteins PEX5p, PEX13p, PEX14p, PEX11β, PEX19p, the peroxisomal membrane lipid transporter ABCD3, and catalase. Expression of PEX14p and ABCD3 was also enhanced in lungs from Mtb aerosol-infected mice. This is the first report that peroxisome-mediated control of ROS balance is essential for innate immune responses to Mtb but can be counteracted by the mycobacterial acetyltransferase Rv3034c. Thus, peroxisomes represent interesting targets for host-directed therapeutics to tuberculosis.     

Interplay of Ferritin Accumulation and Ferroportin Loss in Ageing Brain: Implication for Protein Aggregation in Down Syndrome Dementia,Alzheimer’s,and Parkinson’s Diseases

Iron accumulates in the ageing brain and in brains with neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and Down syndrome (DS) dementia. However, the mechanisms of iron deposition and regional selectivity in the brain are ill-understood. The identification of several proteins that are involved in iron homeostasis, transport, and regulation suggests avenues to explore their function in neurodegenerative diseases. To uncover the molecular mechanisms underlying this association, we investigated the distribution and expression of these key iron proteins in brain tissues of patients with AD, DS, PD, and compared them with age-matched controls. Ferritin is an iron storage protein that is deposited in senile plaques in the AD and DS brain, as well as in neuromelanin-containing neurons in the Lewy bodies in PD brain. The transporter of ferrous iron, Divalent metal protein 1 (DMT1), was observed solely in the capillary endothelium and in astrocytes close to the ventricles with unchanged expression in PD. The principal iron transporter, ferroportin, is strikingly reduced in the AD brain compared to age-matched controls. Extensive blood vessel damage in the basal ganglia and deposition of punctate ferritin heavy chain (FTH) and hepcidin were found in the caudate and putamen within striosomes/matrix in both PD and DS brains. We suggest that downregulation of ferroportin could be a key reason for iron mismanagement through disruption of cellular entry and exit pathways of the endothelium. Membrane damage and subsequent impairment of ferroportin and hepcidin causes oxidative stress that contributes to neurodegeneration seen in DS, AD, and in PD subjects. We further propose that a lack of ferritin contributes to neurodegeneration as a consequence of failure to export toxic metals from the cortex in AD/DS and from the substantia nigra and caudate/putamen in PD brain.     

Development of a meta-stable semi-synthetic lubricant for cold rolling of steel

A semi-synthetic meta-stable oil system for cold rolling of steel was developed as a substitute for a mineral oil based ‘stable emulsion’-type soluble oil. The developed oil system, comprising a ‘coating oil’ for post-pickling application and a ‘rolling oil’ for the rolling operation, was tested in the laboratory and subsequently subjected to extensive field trials in an integrated steel plant. Use of the developed oil system resulted in 25–50 per cent lower roll loads and 30–50 per cent reduction of inter-stand tensions compared with the mineral oil-based ‘stable emulsion’. It was also possible to increase the ‘strip reduction ratio’ and input coil width with the use of the newly-developed oil. Overall performance of the new semi-synthetic oil was found to be far superior to that of the mineral oil based ‘stable emulsion’.     

Optimization of Protoplast Isolation and Transformation for a Pilot Study of Genome Editing in Peanut by Targeting the Allergen Gene Ara h 2

The cultivated peanut (Arachis hypogaea L.) is a legume consumed worldwide in the form of oil, nuts, peanut butter, and candy. Improving peanut production and nutrition will require new technologies to enable novel trait development. Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR–Cas9) is a powerful and versatile genome-editing tool for introducing genetic changes for studying gene expression and improving crops, including peanuts. An efficient in vivo transient CRISPR–Cas9- editing system using protoplasts as a testbed could be a versatile platform to optimize this technology. In this study, multiplex CRISPR–Cas9 genome editing was performed in peanut protoplasts to disrupt a major allergen gene with the help of an endogenous tRNA-processing system. In this process, we successfully optimized protoplast isolation and transformation with green fluorescent protein (GFP) plasmid, designed two sgRNAs for an allergen gene, Ara h 2, and tested their efficiency by in vitro digestion with Cas9. Finally, through deep-sequencing analysis, several edits were identified in our target gene after PEG-mediated transformation in protoplasts with a Cas9 and sgRNA-containing vector. These findings demonstrated that a polyethylene glycol (PEG)-mediated protoplast transformation system can serve as a rapid and effective tool for transient expression assays and sgRNA validation in peanut.