Measurement and Prediction of the Rate of Loss of Sulphur Dioxide from Beer

The total sulphur dioxide (SO₂) concentration of beers decreases during storage, essentially following first-order kinetics. Beers differ in the rate at which they lose SO₂. Half-lives for total SO₂ loss in 22 commercial beers stored at 25°C ranged from 37·7 days to more than 1000 days. The rate of loss could be predicted from beer compositional data using partial least squares (PLS) regression modelling. Initial concentrations of total SO₂, sugars and ions were important factors in the models.     

Method development and survey of Sudan I–IV in palm oil and chilli spices in the Washington,DC, area

Sudan I, II, III and IV dyes are banned for use as food colorants in the United States and European Union because they are toxic and carcinogenic. These dyes have been illegally used as food additives in products such as chilli spices and palm oil to enhance their red colour. From 2003 to 2005, the European Union made a series of decisions requiring chilli spices and palm oil imported to the European Union to contain analytical reports declaring them free of Sudan I–IV. In order for the USFDA to investigate the adulteration of palm oil and chilli spices with unapproved colour additives in the United States, a method was developed for the extraction and analysis of Sudan dyes in palm oil, and previous methods were validated for Sudan dyes in chilli spices. Both LC-DAD and LC-MS/MS methods were examined for their limitations and effectiveness in identifying adulterated samples. Method validation was performed for both chilli spices and palm oil by spiking samples known to be free of Sudan dyes at concentrations close to the limit of detection. Reproducibility, matrix effects, and selectivity of the method were also investigated. Additionally, for the first time a survey of palm oil and chilli spices was performed in the United States, specifically in the Washington, DC, area. Illegal dyes, primarily Sudan IV, were detected in palm oil at concentrations from 150 to 24 000 ng ml^–1. Low concentrations (< 21 µg kg^–1) of Sudan dyes were found in 11 out of 57 spices and are most likely a result of cross-contamination during preparation and storage and not intentional adulteration.     

Calcium losses from a forested catchment in south-central Ontario,Canada

Mass balance studies at a number of calibrated watersheds in eastern North America suggest that large losses of Ca from soil have occurred due to acid deposition. However, there is considerable controversy over whether losses have occurred from the exchangeable pool or whether there are other sources of Ca that have not been considered. Mass balance calculations at a small, calibrated catchment (PC1) in south-central Ontario also indicate that large losses of Ca have occurred over the past 2 decades. If the exchangeable Ca pool has declined by approximately 40% between 1983/1984 and 1998/1999 but the exchangeable Mg pool has remained relatively stable, these changes should be evident in streamwater chemistry. The slope of the buffer curve relating Ca to (sigma)acid anions (F(Ca)) decreased significantly over the study period. We estimate that F(Ca) decreased by 12-24% between 1983 and 1999, although the level of decrease is affected by changes in hydrology. During the same period, there was no significant change in F(Mg), and the annual volume-weighted Ca:Mg (equiv/equiv) ratio in streamwater decreased from approximately 2.8 to approximately 2.1. Measured changes in streamwater chemistry translate into Ca losses from the exchangeable pool of approximately 250-570 mequiv/m2 over the study period, which is similar to estimated losses based on soil measurements (approximately 425 mequiv/m2) and mass balance calculations (approximately 380-430 mequiv/m2). The magnitude of Ca loss cannot be explained by decreases in Ca deposition or decreased Ca weathering. Large Ca losses from the soil exchangeable pool have serious implications for future forest health and the recovery of streamwater from acid deposition.     

A behavioral comparison between motorcyclists and a matched group of non-motorcycling car drivers: factors influencing accident risk

Motorcyclists and a matched group of non-motorcycling car drivers were assessed on behavioral measures known to relate to accident involvement. Using a range of laboratory measures, we found that motorcyclists chose faster speeds than the car drivers, overtook more, and pulled into smaller gaps in traffic, though they did not travel any closer to the vehicle in front. The speed and following distance findings were replicated by two further studies involving unobtrusive roadside observation. We suggest that the increased risk-taking behavior of motorcyclists was only likely to account for a small proportion of the difference in accident risk between motorcyclists and car drivers. A second group of motorcyclists was asked to complete the simulator tests as if driving a car. They did not differ from the non-motorcycling car drivers on the risk-taking measures but were better at hazard perception. There were also no differences for sensation seeking, mild social deviance, and attitudes to riding/driving, indicating that the risk-taking tendencies of motorcyclists did not transfer beyond motorcycling, while their hazard perception skill did.     

Allelic isoforms of the H+/nucleoside co-transporter (CaCNT) from Candida albicans reveal separate high- and low-affinity transport systems for nucleosides

Contigs 19-10196 and 19-20196 of the Stanford Candida albicans genome sequence databank encode two putative allelic isoforms of C. albicans CaCNT, a recently characterized 608 amino acid residue H+-coupled fungal member of the CNT family of concentrative nucleoside transport proteins. The single Ser/Gly difference between CaCNT/19-20196 and CaCNT occurs at position 328 in putative TM 7, and corresponds to a Ser/Gly substitution previously shown to contribute to the contrasting pyrimidine and purine nucleoside selectivities of human (h) and rat (r) Na+-dependent CNT1 and CNT2. CaCNT/19-10196 differs from CaCNT by four amino acids, but has Gly at position 328. These new proteins were recreated by site-directed mutagenesis of CaCNT and characterized functionally by heterologous expression in Xenopus laevis oocytes. In marked contrast to h/rCNT1/2, both CaCNT/19-10196 and CaCNT/19-20196 exhibited permeant selectivities for purine nucleosides (adenosine, guanosine and inosine) and uridine similar to that of CaCNT. However, although H+-coupled, CaCNT/19-20196 exhibited a approximately 10-fold higher apparent Km for uridine than either CaCNT or CaCNT/19-10196. CaCNT/19-20196 also exhibited a low apparent affinity for inosine. We conclude that the three proteins correspond to high-affinity (CaCNT, CaCNT/19-10196) and low-affinity (CaCNT/19-20196) allelic isoforms of the C. albicans CNT nucleoside transporter. This is the first example of a single amino acid residue substitution altering a CNT protein's overall apparent affinity for nucleosides.     

Urban Runoff Quality Characterization and Load Estimation in Saskatoon, Canada

The improvement in the effluent quality of the treated sanitary sewage entering the South Saskatchewan River at Saskatoon, Canada, and the impending change in provincial legislation governing urban runoff, provided the impetus for Saskatchewan Environment to initiate the stormwater runoff quality study reported in this paper. Among others, the study involved a field program for characterizing the urban runoff water quality from four catchments, each representing a different type of land use. Both a site mean concentration approach and a multiple variable regression analysis approach were used to quantify the pollutant load contained within the runoff. Thereafter, using the runoff water quality characterizations developed in the study, rainfall–runoff pollutant loads from the entire city were estimated and compared with two local point sources to the receiving stream. On the basis of this analysis, it was found that urban runoff contributes more total suspended solids and total Kjeldahl nitrogen load, similar chemical oxygen demand load, and slightly less total phosphorus load than the two local point sources.     

Effectiveness of GFRP Sheets for Shear Strengthening of Timber

The objective of this study was to develop a cost-effective shear-strengthening technique for timber stringers that is environmentally friendly and leads to a durable structure. Testing was performed on creosote-treated Douglas fir beams, with dimensions of 100×400×3,650?mm, removed from a 40 year old bridge. Two strengthening schemes were investigated; incorporating vertical and diagonal glass fiber-reinforced polymer (GFRP) sheets applied to both shear spans. The diagonal scheme proved effective in increasing the average ultimate load, flexural stiffness, and deformability of the beams. Performance of the members reinforced using the vertical scheme, however, was poor compared to diagonally reinforced beams. The contribution of the diagonal sheets to the shear capacity of the stringers was around 12% at service loads and 40% at ultimate load. In conclusion, this study has shown that diagonal GFRP sheets are more effective than vertical sheets in shear-strengthening timber stringers with horizontal splits at their ends.     

Cationic Polymer Modified Mesoporous Silica Nanoparticles for Targeted siRNA Delivery to HER2+ Breast Cancer

In vivo delivery of siRNAs designed to inhibit genes important in cancer and other diseases continues to be an important biomedical goal. A new nanoparticle construct that is engineered for efficient delivery of siRNA to tumors is now described. The construct comprises a 47‐nm mesoporous silica nanoparticle core coated with a crosslinked polyethyleneimine–polyethyleneglycol copolymer, carrying siRNA against the human epidermal growth factor receptor type 2 (HER2) oncogene, and coupled to the anti‐HER2 monoclonal antibody (trastuzumab). The construct is engineered to increase siRNA blood half‐life, enhance tumor‐specific cellular uptake, and maximize siRNA knockdown efficacy. The optimized anti‐HER2 nanoparticles produce apoptotic death in HER2 positive (HER2⁺) breast cancer cells grown in vitro, but not in HER2 negative (HER2^?) cells. One dose of the siHER2–nanoparticles reduces HER2 protein levels by 60% in trastuzumab‐resistant HCC1954 xenografts. Administration of multiple intravenous doses over 3 weeks significantly inhibits tumor growth (p < 0.004). The siHER2‐nanoparticles have an excellent safety profile in terms of blood compatibility and low cytokine induction, when exposed to human peripheral blood mononuclear cells. The construct can be produced with high batch‐to‐batch reproducibility and the production methods are suitable for large‐scale production. These results suggest that this siHER2‐nanoparticle is ready for clinical evaluation.