Thermoluminescence apparatus using PT100 resistors as the heating and sensing elements

A novel apparatus for obtaining thermoluminescence glow curves is described. Two standard PT100 precision resistors, which have a well-known dependence of resistance on temperature, are connected back to back to provide a sensing and heating element. The resulting hot finger has very low thermal mass, is nonreactive, and is inexpensive. With dry nitrogen gas-flow cooling, an operational range of -50 to 450 degrees C is achievable. A tailored control circuit which is easily calibrated drives the heating element, and temperature ramps are implemented in software. The simple design permits the use of modularly interchangeable hot fingers for rapid measurement of many samples.     

Development of a smart packaging for the monitoring of fish spoilage

There is much interest from the fisheries industry in developing rapid methods to evaluate real-time freshness of fish and seafood products. Emphasis is on the ones that would reflect and account for the products history and their storage conditions from “harvest-to-home”. The development of a “smart packaging” that monitors the microbial breakdown products in the headspace of packaged fish is described. When fish spoils it releases a variety of basic volatile amines which are detectable with appropriate pH indicating sensors. These are prepared by entrapping within a polymer matrix a pH sensitive dye that responds, through visible color changes to the spoilage volatile compounds that contribute to a quantity known as total volatile basic nitrogen (TVB-N). Laboratory trials on fresh fish filets showed that the sensor accurately tracks the increase in amines concentration in the package headspace. The response was also found to correlate to changing microbial populations (total viable count or TVC and Pseudomonas spp.). In addition, leaching of the dye was assessed over time to assess the suitability of the sensor formulation for food packaging application.     

Managing airport stormwater containing deicers: challenges and opportunities

Stormwater runoff at airports is a significant and costly issue, especially for the stormwater laden with deicing contaminants of high Biochemical Oxygen Demand (BOD) and aquatic toxicity. To reduce the loading of deicing constituents in stormwater and to manage the increasing pressure of tightening regulations, identifying fate and transport and evaluating environmental risks of deicing stormwater are of critical importance. In this review, the regulatory development of airport deicing stormwater management was first discussed, along with the milestone Airport Cooperative Research Program (ACRP) Report 14 publication. The deicer usage and fugitive losses can be reduced and the amount of deicer collected can be increased by having a better understanding of the fate and transport of deicing constituents in stormwater. As such, an overview and evaluation of the constituents of concern in deicers were provided to support the assessment of environmental impacts and mitigation recommendations. The state of knowledge of airport deicing stormwater management was then reviewed, which needs to be synthesized into a national guidance document. A guidebook and a decision tool for airports were proposed to adopt specific practical stormwater management strategies while balancing their priorities in environmental, economic, and social values against operational constraints. These challenges pose great opportunities to improve the current practices of airport deicing stormwater management.     

The generation of hydrophilic polypeptide-siloxane conjugates via n-carboxyanhydride polymerisation

A novel methodology to create covalently linked polypeptide-siloxane hybrid materials by controlled n-carboxyanhydride ring opening polymerisation is disclosed. Poly-l-glutamic acid and poly-l-lysine conjugated products were formed that possessed excellent surface wettability. In addition, the poly-l-lysine-siloxane hybrids formed demonstrated bactericidal attributes against gram-positive Staphylococcus aureus and gram-negative Escherichia coli. It is anticipated that these materials may be of significance for the generation of hydrophilic siloxane-containing polymers that are commonly employed in contemporary medical devices.     

Between facets and domains: 10 aspects of the Big Five.

Factor analyses of 75 facet scales from 2 major Big Five inventories, in the Eugene-Springfield community sample (N=481), produced a 2-factor solution for the 15 facets in each domain. These findings indicate the existence of 2 distinct (but correlated) aspects within each of the Big Five, representing an intermediate level of personality structure between facets and domains. The authors characterized these factors in detail at the item level by correlating factor scores with the International Personality Item Pool (L. R. Goldberg, 1999). These correlations allowed the construction of a 100-item measure of the 10 factors (the Big Five Aspect Scales [BFAS]), which was validated in a 2nd sample (N=480). Finally, the authors examined the correlations of the 10 factors with scores derived from 10 genetic factors that a previous study identified underlying the shared variance among the Revised NEO Personality Inventory facets (K. L. Jang et al., 2002). The correspondence was strong enough to suggest that the 10 aspects of the Big Five may have distinct biological substrates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessment of Escherichia coli O157:H7-specific bacteriophages e11/2 and e4/1c in model broth and hide environments

The efficacy of bacteriophages e11/2 and e4/1c as potential biocontrol agents for Escherichia coli O157:H7 in food applications was assessed under conditions relevant to the food chain environment. The stability of each phage was determined following exposure to varying environmental conditions (pH, temperature, water activity, and sodium chloride) and the ability of each phage to infect and reduce E. coli O157:H7 numbers under selected conditions was also examined. Both e11/2 and e4/1c significantly (p < 0.05) reduced numbers of E. coli O157:H7 when exposed to pH values ranging from pH > 4 to pH 9, temperatures from 4 °C to 37 °C, water activity values of 0.87 or 0.91 to 1.00 and NaCl concentrations of 1% to 2.5%. Subsequently, a cocktail of both phages was used (e11/2 and e4/1c) to assess reduction of E. coli O157:H7 on cattle hide pieces. This involved inoculating pieces of hide (20 × 20 cm) with E. coli O157:H7 (approximately 10⁶ cfu/cm²) which were subsequently treated with either a suspension of a phage cocktail, consisting of e11/2 and e4/1c (multiplicity of infection of 1000 and 10,000, respectively) or water or not treated. Two different investigations were carried out; immediately or 1 h after treatment application was performed in different experiments. Swab samples taken immediately after phage treatment showed no significant (p > 0.05) reduction of E. coli O157:H7 numbers compared to the water treated or untreated samples. However, an extended exposure time of 1 h following phage application revealed a significant reduction (p < 0.05) (1.5 log₁₀ cfu/cm² reduction) in E. coli O157:H7 numbers compared to the numbers recovered on samples treated with water only. These findings demonstrate the potential use of e11/2 and e4/1c phages as a biocontrol agent for E. coli O157:H7 within various stages of the food chain, including on cattle hide.