The adaptation and validation of the food security scale in a community of Caracas, Venezuela

This paper describes the process of modifying and validating a hunger index developed in the United States by Wehler et al (1992). It is part of a research whose main objective is to develop and validate a simple method that measures both quantitative (food sufficiency) and qualitative (female self-perception) dimensions of household food insecurity. In a pilot study, the original instrument was modified from a 2 point 8 item to a 4 point 12 item scale. Precision measured with Alpha Chronbach's coefficient was high (0.871) suggesting consistency in the scale's items. The instrument was applied to a sample of 238 poor and very poor households in a peri-urban barrio of Caracas. To determine overall internal validity of the scale the relationship between possible economic, social and behavioral determinants and food security level measured with the scale, was analyzed. Construct validity of the scale was established with factor and principal components analysis. Finally, with multiple regression analysis evidence is presented for overall validity of the scale. Four determinants: predictors of food sufficiency score, monthly income per capita, social class, and number of children in the household predict in the expected direction self-perceived food security level (R2 = 0.343). Results suggest that this instrument, together with an abbreviated measure of food sufficiency, based on strategic foods may be a valid, precise, and simple method for identifying and monitoring households that suffer from some degree of food insecurity in poor urban communities.     

Variable temperature13C MAS NMR of KFe2Mn(CO)12 in the solid state and as aCatalyst precursor on a carbon support

Variable temperature¹³C MAS NMR spectra are reported for¹³CO-enriched KFe₂Mn(CO)₁₂ as a solid and also as dispersed clusters on a carbon support. The spectrum of KFe₂Mn(CO)₁₂ at 300 K agrees with the proposed structure for this cluster and shows that the cluster is static. Two bridging carbonyl resonances are clearly resolved and, by comparison with¹³C MAS NMR spectra of Mn₂(CO)₁₀ and Fe₂(CO)₉, all terminal resonances for the cluster can be assigned. When the cluster is supported on carbon, two broad resonances are observed at room temperature which are assignable to KFe₂Mn(CO)₁₂ and a decomposition product, Mn₂(CO)₁₀. The carbonyl ligands in both supported clusters are completely averaged, and KFe₂Mn(CO)₁₂ on the carbon surface demonstrates fluxional behavior similar to that observed for the cluster in solution. For this fluxional process, activation energies of 0.6 kcal/mol and 0.5 kcal/mol are estimated for carbon-supported KFe₂Mn(CO)₁₂ and Mn₂(CO)₁₀, respectively.     

Analysis of exempt paint solvents by gas chromatography using solid-phase microextraction

Acetone, methyl acetate, and parachlorobenzotrifluoride (PCBTF or Oxsol? 100) have been exempted as VOC solvents by the U.S. Environmental Protection Agency. In measuring coating VOC content, separate methods for determining exempt solvents are required. One such method utilizes solid-phase microextraction (SPME) to sample the headspace of solvent-based coatings to which the surrogates acetone-d6, methyl acetate-d3, and/or metachlorobenzotrifluoride have been added. The sampled exempt coating solvents are thermally desorbed and analyzed using gas chromatography with flame ionization or mass spectral detection. The SPME headspace method has also been used to analyze MEK, butyl acetate, tert-butyl acetate, toluene, and xylene in solventborne coatings, and alcohols in waterborne systems. This paper presents the results obtained for acetone and toluene in a large number of aerosol paints. Additionally, the results from a round-robin study for acetone, methyl acetate, and parachlorobenzotrifluoride in commercial solvent-based coatings are reported.     

In situ repair welding of steam turbine shroud for replacing a cracked blade

A root-cracked blade in a high-pressure steam turbine of a nuclear power plant had to be replaced with a new blade by cutting the shroud to remove the cracked blade. This necessitated in situ welding of a new shroud piece with the existing shroud after the blade replacement. The in situ welding of the shroud, a 12% Cr martensitic stainless steel with tempered martensite microstructure, was carried out using gastungsten arc welding and 316L austenitic stainless steel filler metal followed by localized postweld heat treatment at 873 K for 1 h using a specially designed electrical resistance-heating furnace. Mock-up trials were carried out to ensure that sound welds could be made under the constraints present during the in situ repair welding operation. In situ metallography of the repair weld after postweld heat treatment confirmed the adequate tempering of the martensitic structure in the heat-affected zone. Metallurgical investigations carried out in the laboratory on a shroud test-piece that had been welded using the same procedure as employed in the field confirmed the success of the in situ repair operation. The alternate option available was replacing the cracked blade and the shroud piece to which it is riveted with a new one, reducing the height of all the blades attached to the shroud by machining, riveting the blades with reduced height to the new shroud, and, finally, dynamic balancing of the entire turbine after completion of the repair. This option is both time-consuming and expensive. Hence, the successful completion of this repair welding resulted in enormous savings both in terms of reducing the downtime of the plant and the cost of the repair. The turbine has been put back into service and has been operating satisfactorily since December 2000.     

Identification of Lysophosphatidylcholine–Chlorohydrin in Human Atherosclerotic Lesions

Lysophosphatidylcholine (LysoPtdCho) levels are elevated in sera in patients with atherosclerosis and in atherosclerotic tissue. Previous studies have shown that reactive chlorinating species attack plasmalogens in human coronary artery endothelial cells (HCAEC), forming lysoPtdCho and lysoPtdCho–chlorohydrin (lysoPtdCho–ClOH). The results herein demonstrate for the first time that lysoPtdCho–ClOH is elevated over 60-fold in human atherosclerotic lesions. In cultured HCAEC, 18:0 lysoPtdCho–ClOH led to a statistically significant increase in P-selectin cell-surface expression, but unlike 18:1 lysoPtdCho did not lead to cyclooxygenase-2 protein expression. These data show that 18:0 lysoPtdCho–ClOH is elevated in atherosclerotic tissue and may have unique pro-atherogenic properties compared to lysoPtdCho.     

Quantification of Pentafluorobenzyl Oxime Derivatives of Long Chain Aldehydes by GC–MS Analysis

Negative ion mass spectrometric techniques, for compounds having good ionization properties, such as pentafluorobenzyl derivatives, are believed to be more sensitive than positive ion methods. Preparation of PFB oximes of fatty aldehydes from crude lipid extracts is problematic due to the release of free aldehydes from plasmalogens during derivatization. Accordingly, in these studies plasmalogens were removed by silicic acid column chromatography prior to pentafluorobenzyl derivatization. This simple purification step to remove plasmalogens is shown to facilitate the quantification of long-chain aldehydes by analysis of their pentafluorobenzyl oxime derivatives utilizing gas chromatography–mass spectrometry in the negative ion chemical ionization mode. The limit of detection for long chain fatty aldehydes using this method is 0.5 pmol and it is linear over two orders of magnitude. Silicic acid column chromatography followed by electrospray ionization mass spectrometry demonstrated that plasmalogens were removed (the detection limit for this analyses was ≤0.3 pmol). Furthermore, we have exploited the utility and sensitivity of this method to identify increases in hexadecanal and octadecanal in 3-amino-1,2,4-triazole treated human neutrophils. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Reactivation of a Carbon-supported Gold Catalyst for the Hydrochlorination of Acetylene

Acetylene hydrochlorination using a carbon-supported gold catalyst is studied. Reactivation of the catalyst is demonstrated using a brief treatment of the spent catalyst with boiling aqua regia and the process of reactivation and deactivation is characterised using X-ray photoelectron spectroscopy. Deactivation is considered to be due to loss of Au³⁺ which is restored by the aqua regia treatment.     

The role of support on the performance of platinum-based catalysts for the total oxidation of polycyclic aromatic hydrocarbons

A range of Pt supported catalysts have been evaluated for the total oxidation of naphthalene. Catalysts contained 0.5 wt% Pt on a range of supports (γ-Al₂O₃, TiO₂, SiO₂, SnO₂, and CeO₂₎. SiO₂ was the best support, the 0.5%Pt/SiO₂ catalyst showing a conversion to carbon dioxide of over 90% at 200 °C (100 vppm naphthalene, GHSV = 45,000 h⁻¹). The catalyst also showed a considerably higher activity (in the temperature range 100–175 °C) than a CeO₂ catalyst recently reported to be one of the most effective catalysts for the total oxidation of naphthalene. The high activity of the 0.5%Pt/SiO₂ catalyst has been attributed to the relatively low dispersion and relatively large size of Pt particles. Furthermore, due to the acidic and non-reducible nature of the SiO₂, platinum is expected to have a weak interaction with the support. XPS data identified the presence of Pt⁰ on the surface and this contributes to the high activity.