Testing the durability of wood

The use of wood is limited due to its susceptibility to wood destroying organisms. If wet for long periods, wood will be attacked by fungi and the strength properties will decrease dramatically. To overcome this disadvantage, non-durable wood can be treated with preserving chemicals. When testing durability, it is essential that wood be exposed to all kinds of wood degrading organisms that can be expected in the intended exposure environment. The aim of this study was to evaluate the relevance of exposing test ttakes in terrestrial microcosms (TMC) as an alternative to existing test procedures to judge the durability of treated and untreated wood. Small stakes of treated and untreated pine (Pinus sylvestris) sapwood were exposed in TMCs with different soils. Stakes were also exposed to pure cultures of brown and white rot fungi. After exposure, mass losses were determined and stakes from the TMCs were analysed using light microscopy to determine the types of microbial attack. The effect of the preservatives varied depending on the exposure environment. It is concluded that testing the durability of untreated and treated wood with pure cultures of fungi is too limited a test to evaluate total effectiveness. Testing in TMCs represents a good complement to existing procedures and, after further development, an alternative to other laboratory and field tests.

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Résumé La vulnérabilité du bois aux micro-organismes est un facteur qui limite son usage. Lorsqu'il est mouillé pendant une période prolongée, le bois sera attaqué par des champignons, ce qui diminuera dramatiquement sa résistance. Pour pallier à ce désavantage, on peut traiter les bois les moins résistants avec des produits de préservation. Afin d'évaluer sa durabilité après traitement, il est alors essentiel d'exposer le bois à tous les types d'organismes destructeurs pouvant se trouver dans le milieu où il sera utilisé. Le but de cette étude est d'évaluer l'exposition des piquets de bois dans des microcosmes terrestres, en tant qu'essai alternatif aux procédures existantes pour évaluer la résistance des bois traités et non traités. Des petits piquets de pin sylvestre, Pinus sylvestris, traités et non traités, ont été exposés à des microcosmes terrestres, utilisant des sols différents. Les piquets ont également été exposés à des cultures pures de champignons de carie blanche et de carie brune. Après l'essai, les pertes de masse ont été déterminées et les piquets ont été analysés au microscope photonique afin d'identifier le type d'attaque microbienne subie. L'effet des produits de préservation a varié selon le milieu auquel les bois traités ont été exposés. On a conclu que des essais de durabilité effectués sur des bois traités et non traités, uniquement en présence de cultures pures de champignons, sont trop limités pour prédire l'efficacité totale d'un produit de préservation. Les essais effectués dans des microcosmes terrestres peuvent être un bon complément aux procédures existantes. Ils peuvent même devenir, après des recherches supplémentaires, une alternative à d'autres essais sur le terrain et en laboratoire.

     

Effects of phleomycin-induced DNA damage on the fission yeast Schizosaccharomyces pombe cell cycle

The effect of phleomycin, a bleomycin-like antibiotic, has been investigated in the fission yeast, Schizosaccharomyces pombe. We report that in response to phleomycin-induced DNA damage, growth was inhibited and S. pombe cells arrested in the G2-phase of the cell cycle. DNA repair mutants rad9 and rad17 did not arrest and were hypersensitive to phleomycin. Cell cycle mutants that entered mitosis without monitoring the completion of DNA replication also displayed an increased sensitivity to this DNA-damaging agent. Thus, phleomycin could be used as a tool in the fission yeast S. pombe model system for the study of DNA damage and cell cycle checkpoints, or as a new selective agent.     

Computation of isothermal sections of the Al-H-Mg system

The numerical method developed by Kaufman and Nesor is applied to calculate the phase diagrams of the binary systems Al-Li, Al-Mg and Li-Mg. Information on the thermodynamics of the solution as well as on the thermodynamics of the binary compounds are derived and, when available, compared with experimental results.Isothermal sections of the ternary system, Al-Li-Mg are estimated at temperatures of interest for the lithium battery developed at Argonne National Laboratory (T = 648, 673, 723 and 773 K). The calculations of these sections are based mainly on information derived from the analyses of the binary subsystems. Until further experimental evidence is obtained on the stability and existence of ternary compounds in the temperature range of interest for us, we have not included any ternary compound in our computations.     

Line ‘Em Up: Advances in Alignment Technology and their Impact on Translation Support Tools

We present a quantitative evaluation of one well-known word-alignment algorithm, as well as an analysis of frequent errors in terms of this model's underlying assumptions. Despite error rates that range from 22% to 32%, we argue that this technology can be put to good use in certain automated aids for human translators. We support our contention by pointing to several successful applications and outline ways in which text alignments below the sentence level would allow us to improve the performance of other translation support tools.     

Furan formation from vitamin C in a starch-based model system: Influence of the reaction conditions

The generation of furan from vitamin C during thermal treatment of a starch-based model system, which simulated baby food, was studied. Results indicated that the amount of sample heated in the vial influenced the furan generation from ascorbic acid. Increasing the amount of heated sample from 5% to approximately 98% of the total vial volume, drastically reduced furan formation from 70 ppb to 16 ppb. Changes in ascorbic acid concentrations from 0.1 to 4.5 mg/g did not influence furan concentration nor did different ascorbic/dehydroascorbic acid molar ratios. Interestingly, waxy corn starch itself considerably enhanced furan generation from ascorbic acid. Under the same conditions, 13.2 ppb of furan was generated in starch-based samples, while in ascorbic acid buffered solutions only 0.4 ppb of furan was formed. Application of other matrices, in particular agar and hydrolysed starch, resulted in similar furan concentrations as for native starch, while in polyol solutions furan concentrations were comparable to those obtained for the buffered ascorbic acid solutions.     

Treatment of estrogens and androgens in dairy wastewater by a constructed wetland system

Constructed wetland systems (CWS) have been used as a low cost bio-filtration system to treat farm wastewater. While studies have shown that CWS are efficient in removing organic compounds and pathogens, there is limited data on the presence of hormones in this type of treatment system.The objective of this study was to evaluate the ability of the CWS to reduce estrogenic and androgenic hormone concentration in dairy wastewater. This was achieved through a year long study on dairy wastewater samples obtained from a surface flow CWS. Analysis of hormonal levels was performed using a solid phase extraction (SPE) sample clean-up method, combined with reporter gene assays (RGAs) which incorporate relevant receptors capable of measuring total estrogenic or androgenic concentrations as low as 0.24 ng L⁻¹ and 6.9 ng L⁻¹ respectively. Monthly analysis showed a mean removal efficiency for estrogens of 95.2%, corresponding to an average residual concentration of 3.2 ng L⁻¹ 17β-estradiol equivalent (EEQ), below the proposed lowest observable effect concentration (LOEC) of 10 ng L⁻¹. However, for one month a peak EEQ concentration of 115 ng L⁻¹ was only reduced to 18.8 ng L⁻¹. The mean androgenic activity peaked at 360 ng L⁻¹ and a removal efficiency of 92.1% left an average residual concentration of 32.3 ng L⁻¹ testosterone equivalent (TEQ).The results obtained demonstrate that this type of CWS is an efficient system for the treatment of hormones in dairy wastewater. However, additional design improvements may be required to further enhance removal efficiency of peak hormone concentrations.     

Microbial contamination associated with the processing of grilled pork,a ready-to-eat street food in Benin

This study aimed to assess the microbial contamination associated with the traditional processing of fresh pork into grilled pork in Benin. Sixty samples of meat, including fresh pork and processed pork were randomly collected from different processing/selling sites, and the main foodborne microorganisms were sought using standard methods. The Aerobic Mesophilic Bacteria load in all samples ranged between 2.7 and 7.4 Log₁₀ CFU g⁻¹, with 16.7% of samples exceeding the acceptable limit of <7.0 Log₁₀ CFU g⁻¹ recommended by the Health Protection Agency for this criterion. Likewise, Enterobacteriaceae, Escherichia coli, and Clostridium perfringens loads exceeded the acceptable limit in 20.8, 20.8, and 12.5% of the samples, respectively. None of the samples contained Salmonella spp., Staphylococcus aureus or Listeria monocytogenes. Sources of contamination of grilled pork were identified and grouped into five types of causes related to processors, processing methods, equipment used, raw materials, and processing/selling environment. Similarly, a microbiological hazard analysis of grilled pork processing practices identified the sensitive steps where additional hygiene measures needed to be implemented.     

LC-MS/MS multi-analyte method for mycotoxin determination in food supplements

A multi-analyte method for the liquid chromatography-tandem mass spectrometric determination of mycotoxins in food supplements is presented. The analytes included A and B trichothecenes (nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, neosolaniol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin and T-2 toxin), aflatoxins (aflatoxin-B₁, aflatoxin-B₂, aflatoxin-G₁ and aflatoxin-G₂), Alternaria toxins (alternariol, alternariol methyl ether and altenuene), fumonisins (fumonisin-B₁, fumonisin-B₂ and fumonisin-B₃), ochratoxin A, zearalenone, beauvericin and sterigmatocystin. Optimization of the simultaneous extraction of these toxins and the sample pretreatment procedure, as well as method validation were performed on maca (Lepidium meyenii) food supplements. The results indicated that the solvent mixture ethyl acetate/formic acid (95:5, v/v) was the best compromise for the extraction of the analytes from food supplements. Liquid–liquid partition with n-hexane was applied as partial clean-up step to remove excess of co-extracted non-polar components. Further clean-up was performed on Oasis HLB? cartridges. Samples were analysed using an Acquity UPLC system coupled to a Micromass Quattro Micro triple quadrupole mass spectrometer equipped with an electrospray interface operated in the positive-ion mode. Limits of detection and quantification were in the range of 0.3–30 ng g^?1 and 1–100 ng g^?1, respectively. Recovery yields were above 60% for most of the analytes, except for nivalenol, sterigmatocystine and the fumonisins. The method showed good precision and trueness. Analysis of different food supplements such as soy (Glycine max) isoflavones, St John's wort ( Hypericum perforatum), garlic (Allium sativum), Ginkgo biloba, and black radish (Raphanus niger) demonstrated the general applicability of the method. Due to different matrix effects observed in different food supplement samples, the standard addition approach was applied to perform correct quantitative analysis. In 56 out of 62 samples analysed, none of the 23 mycotoxins investigated was detected. Positive samples contained at least one of the toxins fumonisin-B₁, fumonisin-B₂, fumonisin-B₃ and ochratoxin A.     

Risk assessment for furan contamination through the food chain in Belgian children

Young, old, pregnant and immuno-compromised persons are of great concern for risk assessors as they represent the sub-populations most at risk. The present paper focuses on risk assessment linked to furan exposure in children. Only the Belgian population was considered because individual contamination and consumption data that are required for accurate risk assessment were available for Belgian children only. Two risk assessment approaches, the so-called deterministic and probabilistic, were applied and the results were compared for the estimation of daily intake. A significant difference between the average Estimated Daily Intake (EDI) was underlined between the deterministic (419 ng?kg(-1) body weight (bw) day(-1)) and the probabilistic (583 ng?kg(-1) bw day(-1)) approaches, which results from the mathematical treatment of the null consumption and contamination data. The risk was characterised by two ways: (1) the classical approach by comparison of the EDI to a reference dose (RfD(chronic-oral)) and (2) the most recent approach, namely the Margin of Exposure (MoE) approach. Both reached similar conclusions: the risk level is not of a major concern, but is neither negligible. In the first approach, only 2.7 or 6.6% (respectively in the deterministic and in the probabilistic way) of the studied population presented an EDI above the RfD(chronic-oral). In the second approach, the percentage of children displaying a MoE above 10,000 and below 100 is 3-0% and 20-0.01% in the deterministic and probabilistic modes, respectively. In addition, children were compared to adults and significant differences between the contamination patterns were highlighted. While major contamination was linked to coffee consumption in adults (55%), no item predominantly contributed to the contamination in children. The most important were soups (19%), dairy products (17%), pasta and rice (11%), fruit and potatoes (9% each).