Sodium metabisulfite and SO2 release: an under-recognized hazard among shrimp fishermen

Since the introduction of sodium metabisulfite as a food preservative, it has been associated with several idiosyncratic reactions (eg, bronchospasm, oculonasal symptoms, and urticaria/angioedema) in sulfite-sensitive individuals. The pathogenic mechanism of these reactions is not yet understood. We report the case of two crewmen on a shrimp trawler who were found dead in the ship's hold. Their deaths had occurred while they were applying dry sodium metabisulfite, referred to as "shrimp dip" in the shrimping industry. Postmortem examinations showed diffuse pulmonary edema consistent with death secondary to asphyxia. Associated findings were visceral congestion. Although it is possible to measure death from sodium metabisulfite with available records, its potential morbidity cannot be estimated. It is known that sodium metabisulfite can react with acids and water, releasing toxic sulfur dioxide (SO2) gas. In addition, SO2 gas reacts with respiratory tissue forming sulfureous acid, and inducing a pulmonary reaction causing hypoxemia. Furthermore, sodium metabisulfite, compared with sodium bisulfite, has a much greater propensity to release SO2 gas. We conclude that there is a need for improved education regarding the potential side effects of sodium metabisulfite, thus eliminating needless occupational morbidity and mortality.     

The role of inorganic polymer technology in the development of ‘green concrete’

The potential position of and drivers for inorganic polymers (“geopolymers”) as an element of the push for a sustainable concrete industry are discussed. These materials are alkali-activated aluminosilicates, with a much smaller CO₂ footprint than traditional Portland cements, and display very good strength and chemical resistance properties as well as a variety of other potentially valuable characteristics. It is widely known that the widespread uptake of geopolymer technology is hindered by a number of factors, in particular issues to do with a lack of long-term (20+ years) durability data in this relatively young research field. There are also difficulties in compliance with some regulatory standards in Europe and North America, specifically those defining minimum clinker content levels or chemical compositions in cements. Work on resolving these issues is ongoing, with accelerated durability testing showing highly promising results with regard to salt scaling and freeze–thaw cycling. Geopolymer concrete compliance with performance-based standards is comparable to that of most other high-strength concretes. Issues to do with the distinction between geopolymers synthesised for cement replacement applications and those tailored for niche ceramic applications are also discussed. Particular attention is paid to the role of free alkali and silicate in poorly-formulated systems and its deleterious effects on concrete performance, which necessitates a more complete understanding of the chemistry of geopolymerisation for the technology to be successfully applied. The relationship between CO₂ footprint and composition in comparison with Portland-based cements is quantified.     

Nodal DG-FEM solution of high-order Boussinesq-type equations

A discontinuous Galerkin finite-element method (DG-FEM) solution to a set of high-order Boussinesq-type equations for modelling highly nonlinear and dispersive water waves in one horizontal dimension is presented. The continuous equations are discretized using nodal polynomial basis functions of arbitrary order in space on each element of an unstructured computational domain. A fourth-order explicit Runge-Kutta scheme is used to advance the solution in time. Methods for introducing artificial damping to control mild nonlinear instabilities are also discussed. The accuracy and convergence of the model with both h (grid size) and p (order) refinement are confirmed for the linearized equations, and calculations are provided for two nonlinear test cases in one horizontal dimension: harmonic generation over a submerged bar, and reflection of a steep solitary wave from a vertical wall. Test cases for two horizontal dimensions will be considered in future work.     

Password memorability and security: empirical results

Users rarely choose passwords that are both hard to guess and easy to remember. To determine how to help users choose good passwords, the authors performed a controlled trial of the effects of giving users different kinds of advice. Some of their results challenge the established wisdom.     

James Bond and citations to his books

This paper investigates two bibliometric problems: the listing of books in a specialist area (ornithology) and the determination of the citation pattern to individual authors, who often re-issue their books in later editions. James Bond, a Philadelphia ornithologist, who specialised in the birds of the West Indies, is used as an example of a naturalist whose long career led to many journal articles and enduring scientific fame through a well-known book. He also attained some unexpected notoriety through the use of his name by a popular novelist. Methods for the evaluation of his book and associated bird checklists in comparison with other similar works are presented on the basis of their citations. This revised version was published online in June 2006 with corrections to the Cover Date.     

Testing a Self-Determination Theory Process Model for Promoting Glycemic Control Through Diabetes Self-Management.

A longitudinal study tested the self-determination theory (SDT) process model of health behavior change for glycemic control within a randomized trial of patient activation versus passive education. Glycosylated hemoglobin for patients with Type 2 diabetes (n=159) was assessed at baseline, 6 months, and 12 months. Autonomous motivation and perceived competence were assessed at baseline and 6 months, and the autonomy supportiveness of clinical practitioners was assessed at 3 months. Perceptions of autonomy and competence were promoted by perceived autonomy support, and changes in perceptions of autonomy and competence, in turn, predicted change in glycemic control. Self-management behaviors mediated the relation between change in perceived competence and change in glycemic control. The self-determination process model fit the data well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrograde Amnesia in Dementia: Comparison of HIV-Associated Dementia, Alzheimer's Disease, and Huntington's Disease.

Remote memory was assessed in persons with HIV-associated dementia (HIV-D), probable Alzheimer's disease (AD), and Huntington's disease (HD) and in healthy controls. The clinical groups were similar in overall dementia severity. Each clinical group exhibited impairments on remote memory tests relative to controls; however, temporally graded memory loss with selective preservation of older information was observed in the AD group but not the HD or HIV-D group. Analysis of cued retrieval indicated a preferential cuing benefit for the HIV-D and HD groups relative to the AD group. The similar pattern of remote memory performance demonstrated by the HIV-D and HD groups is a novel finding and suggests a subcortically mediated retrograde amnesia in HIV-D. The temporally graded pattern and the abnormal cued retrieval performance in the AD group are consistent with a consolidation deficit associated with extrahippocampal (cortical) and hippocampal damage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduction of the Nitrate Content in Baby Spinach Leaves by Vacuum Impregnation with Sucrose

Vacuum impregnation (VI) has been widely utilized as a pre-treatment method prior to, e.g., the minimal processing, freezing, or drying of foods. In many cases, VI has been used to focus on the enrichment of fruits and vegetables with probiotics or micronutrients, texture enhancement, the modification of the sensory attributes, and extension of shelf life by pH reduction. However, little attention has been paid to the exploration of the metabolic consequences of VI that could lead to changes in the quality characteristics of plant tissues. Since nitrate has long been discussed as a compound that is harmful to human health, the aim of this investigation was to reduce the nitrate content in spinach leaves by feeding sucrose into the tissue using VI. The leaves, either non-treated or treated with VI, were stored under saturated humidity conditions and in darkness at 8 °C, for up to 72 h. VI-treated leaves showed a remarkable reduction in nitrate content as compared to the non-treated samples. Upon storage, sucrose was reduced, indicating that this sugar had been respired and had induced metabolization of the stored nitrate. The nitrite content of the treated leaves was unaffected, proving that this toxic compound was not accumulated in the baby spinach leaves upon external sucrose feeding.