An Extended Quadratic Frobenius Primality Test with Average- and Worst-Case Error Estimate

We present an Extended Quadratic Frobenius Primality Test (EQFT), which is related to the Miller-Rabin test and to several other known probabilistic tests. EQFT takes time equivalent to about two or three Miller-Rabin tests, but has a much smaller error probability, namely 256/331776^t for t iterations of the test in the worst case. We also give bounds on the average-case behaviour of the test: consider the algorithm that repeatedly chooses random odd k bit numbers, subjects them to t iterations of our test and outputs the first one found that passes all tests. We obtain numeric upper bounds for the error probability of this algorithm as well as a general closed expression bounding the error. For instance, it is at most 2^-155 for k = 500, t = 2. Compared with earlier similar results for the Miller-Rabin test, the results indicate that our test in the average case has the effect of nine Miller-Rabin tests. We also give bounds for the error in case a prime is sought by incremental search from a random starting point.     

Method validation for strobilurin fungicides in cereals and fruit

Strobilurins are a new class of fungicides that are active against a broad spectrum of fungi. In the present work a GC method for analysis of strobilurin fungicides was validated. The method was based on extraction with ethyl acetate/cyclohexane, clean-up by gel permeation chromatography (GPC) and determination of the content by gas chromatography (GC) with electron capture (EC-), nitrogen/phosphorous (NP-), and mass spectrometric (MS-) detection. Three strobilurins, azoxystrobin, kresoxim-methyl and trifloxystrobin were validated on three matrices, wheat, apple and grapes. The validation was based on recovery tests at three or four spiking levels, determined as double determinations and repeated three times (n = 6). The mean recoveries for the three detectors were in the range of 70-114%, and the LODs were between 0.004mg/kg and 0.014mg/kg, for all three strobilurins. The values for repeatability and reproducibility were within the limits for repeatability and reproducibility given by the Horwitz equation. Validation was not accepted for azoxystrobin in grapes on all three detectors and for azoxystrobin in apple for the MS-detector. A comparison of matrix-matched standards versus standards in solvent showed varying differences     

The community safety approach in Falun, Sweden--is it possible to characterise the most effective prevention endeavours and how long-lasting are the results?

The safe community concept was put into practice in order to reduce the number of unintentional injuries occurring in the Falun municipality. A community-based injury prevention programme was initiated in 1989 and has been gradually built up since that time. The prevention endeavours were based primarily on active intervention strategies through the provision of information, supervision, education and training. After 5 years of an active intervention programme, a significant effect was found as regards the injury rates for both outpatients as well as patients discharged from hospitals. The objectives of this study were: to examine whether the character of the prevention endeavours was a determining factor on the outcome (recorded as in-patient injury cases); to evaluate the effects of this programme, which is still in practice, compared to long-term historical trends; and to draw comparisons with other community-based programmes. A category of 'most targeted risks' was identified as being different with respect to how the injury mechanisms involved were targeted through the programme activities. The development within the injury rates for this group, comprised predominantly of injuries caused by falls at the same level, was significantly different than those for the groups categorized as 'less targeted' and 'non-targeted'. The general effect of the programme appeared to be a neutralization of an otherwise upward trend in the injury rates. A particular effect was demonstrated in the number of fall injuries, including femoral fractures. It was also noted that there was still a reduction in injuries after 7 years. However, it was possible to surmise a waning effect during the last 2 years of the programme while still in progress. This observation suggests that a community-based injury prevention programme must be continuously renewed and reinforced.     

Electricity generation by microbial fuel cells fuelled with wheat straw hydrolysate

Electricity production from microbial fuel cells fueled with hydrolysate produced by hydrothermal treatment of wheat straw can achieve both energy production and domestic wastewater purification. The hydrolysate contained mainly xylan, carboxylic acids, and phenolic compounds. Power generation and substrate utilization from the hydrolysate was compared with the ones obtained by defined synthetic substrates. The power density increased from 47 mW m⁻² to 148 mW m⁻² with the hydrolysate:wastewater ratio (R_HW in m³ m⁻³) increasing from 0 to 0.06 (corresponding to 0-0.7 g dm⁻³ of carbohydrates). The power density with the hydrolysate was higher than the one with only xylan (120 mW m⁻²) and carboxylic acids as fuel. The higher power density can be caused by the presence of phenolic compounds in the hydrolysates, which could mediate electron transport. Electricity generation with the hydrolysate resulted in 95% degradation of the xylan and glucan. The study demonstrates that lignocellulosic hydrolysate can be used for co-treatment with domestic wastewater for power generation in microbial fuel cells.     

Cyclodextrin Aldehydes are Oxidase Mimics

Cyclodextrins containing 6‐aldehyde groups were found to catalyse oxidation of aminophenols in the presence of hydrogen peroxide. The catalysis followed Michaelis–Menten kinetics and is related to the catalysis previously observed with cyclodextrin ketones. A range of different cyclodextrin aldehydes were prepared containing one, two or more aldehydes at the primary rim (6‐positions) or a ethoxy‐2‐al or propoxy‐3‐al at the secondary rim. 2‐O‐ethoxy‐2‐al‐β‐cyclodextrin ( 22 ) was found to be the best catalyst. The aldehydes are in many cases better catalysts than the ketones, because of their powerful covalent binding of hydrogen peroxide.     

Potential bioethanol and biogas production using lignocellulosic biomass from winter rye, oilseed rape and faba bean

To meet the increasing need for bioenergy several raw materials have to be considered for the production of e.g. bioethanol and biogas. In this study, three lignocellulosic raw materials were studied, i.e. (1) winter rye straw (Secale cereale L), (2) oilseed rape straw (Brassica napus L.) and (3) faba bean straw (Viciafaba L.). Their composition with regard to cellulose, hemicellulose, lignin, extractives and ash was evaluated, as well as their potential as raw materials for ethanol and biogas production. The materials were pretreated by wet oxidation using parameters previously found to be optimal for pretreatment of corn stover (195 °C, 15 min, 2 g l⁻¹ Na₂CO₃ and 12 bar oxygen). It was shown that pretreatment was necessary for ethanol production from all raw materials and gave increased biogas yield from winter rye straw. Neither biogas productivity nor yield from oilseed rape straw or faba bean straw was significantly affected by pretreatment. Ethanol was produced by the yeast Saccharomyces cerevisiae during simultaneous enzymatic hydrolysis of the solid material after wet oxidation with yields of 66%, 70% and 52% of theoretical for winter rye, oilseed rape and faba bean straw, respectively. Methane was produced with yields of 0.36, 0.42 and 0.44 l g⁻¹ volatile solids for winter rye, oilseed rape and faba bean straw, respectively, without pretreatment of the materials. However, biogas productivity was low and it took over 50 days to reach the final yield. It could be concluded that all three materials are possible raw materials for either biogas or ethanol production; however, improvement of biogas productivity or ethanol yield is necessary before an economical process can be achieved.