Interaction of Chrysosporium merdarium with titanium oxide surface

The growth of Chrysosporium merdarium on TiO₂ (rutile, anatase) and its possibility to deteriorate the surface were investigated. Treated with fungi and untreated samples of deteriorated TiO₂ surfaces were studied by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Microbial deterioration of TiO₂ is also discussed. The attachment to the TiO₂ surface via metabolic products resulted in the formation of cryptand [2,2,2] complex with Ca²⁺ ions. According to water contact angle (CA) measurements microbial growth increases the wettability of TiO₂ film surfaces. A much more intensive fungal action during microbial treatment on rutile in comparison with that of anatase was observed. A chemical deterioration product, the volatile trimethyl borate, on rutile in exudation of C. merdarium was detected by gas chromatographic–mass spectrometric analysis.     

This is not classified: everyday information seeking and encountering in smart urban spaces

We present a multipronged comparative study of citizens’ self-proclaimed information needs and actual information seeking behavior in smart urban spaces. We first conducted several user studies to identify the types of information services that citizens believed to be useful in urban setting utilizing methods ranging from contextual inquiry with lo-fi prototypes to “card sorting” exercise with a separate set of participants, and finally to implementing selected services. We then made a sizeable constructive intervention into the urban space by deploying in a city center 12 large, interactive public displays called “hotspots” to offer a wide range of previously identified information services. We collected comprehensive qualitative and quantitative data on the usage of the hotspots and their services by the general public during 13 months. Our study reveals discrepancies between a priori and a posteriori information seeking strategies extracted from the self-proclaimed information needs and the actual usage of the hotspots.     

Characterization of porous glass fiber-reinforced composite (FRC) implant structures: porosity and mechanical properties

The aim of this study was to characterize the microstructure and mechanical properties of porous fiber-reinforced composites (FRC). Implants made of the FRC structures are intended for cranial applications. The FRC specimens were prepared by impregnating E-glass fiber sheet with non-resorbable bifunctional bis-phenyl glycidyl dimethacrylate and triethylene glycol dimethacrylate resin matrix. Four groups of porous FRC specimens were prepared with a different amount of resin matrix. Control group contained specimens of fibers, which were bound together with sizing only. Microstructure of the specimens was analyzed using a micro computed tomography (micro-CT) based method. Mechanical properties of the specimens were measured with a tensile test. The amount of resin matrix in the specimens had an effect on the microstructure. Total porosity was 59.5 % (median) in the group with the lowest resin content and 11.2 % (median) in the group with the highest resin content. In control group, total porosity was 94.2 % (median). Correlations with resin content were obtained for all micro-CT based parameters except TbPf. The tensile strength of the composites was 21.3 MPa (median) in the group with the highest resin content and 43.4 MPa (median) in the group with the highest resin content. The tensile strength in control group was 18.9 MPa (median). There were strong correlations between the tensile strength of the specimens and most of the micro-CT based parameters. This experiment suggests that porous FRC structures may have the potential for use in implants for cranial bone reconstructions, provided further relevant in vitro and in vivo tests are performed.     

高速新概念成形——低定量双层箱纸板,变不可能为可能

介绍了一种全新的、已获专利保护的、用单台混合成形单元生产容器用轻量双层箱纸板的成本效益型的概念。新概念将三个独特的部件和技术结合为一体：新型ValFloPro双层流浆箱、VacuBalence真空辅助成形板和ValFormer靴刮刀混合成形器技术。这个具备分层技术的混合成形新概念将纸机运行速度提高到1400m/min,是生产一流质量轻量箱纸板的一种切实可行的替代方案。     

Oxidation of magnesia-supported Pd-clusters leads to the ultimate limit of epitaxy with a catalytic function

Oxide-supported transition-metal clusters and nanoparticles have attracted significant attention owing to their important role as components of model catalysts, sensors, solar cells and magnetic recording devices. For small clusters, functionality and structure are closely interrelated. However, knowledge of the structure of the bare cluster is insufficient as the interaction with the chemical environment might cause drastic structural changes. Here we show by ab initio simulations based on the density functional theory that the reaction with molecular oxygen transforms small, non-crystalline, magnesia-supported Pd-clusters to crystalline Pd(x)O(y) nano-oxide clusters that are in epitaxy with the underlying support. Restructuring of the Pd backbone is controlled by the electrostatic interaction with magnesia leading to a strong reduction of the O2 dissociation barrier. The supported Pd(x)O(y) clusters are likely to serve as Mars-van Krevelen oxygen reservoirs in catalytic oxidation reactions as observed for PdO overlayers and demonstrated here for the oxidation of CO molecules.     

Effects of yeasts and bacteria on the levels of folates in rye sourdoughs

Fermentation of rye dough is often accompanied with an increase in folate content. In this study, three sourdough yeasts, Candida milleri CBS 8195, Saccharomyces cerevisiae TS 146, and Torulaspora delbrueckii TS 207; a control, baker's yeast S. cerevisiae ALKO 743; and four Lactobacillus spp., L. acidophilus TSB 262, L. brevis TSB 307, L. plantarum TSB 304, and L. sanfranciscensis TSB 299 originally isolated from rye sourdough were examined for their abilities to produce or consume folates. The microorganisms were grown in yeast extract-peptone-d-glucose medium as well as in small-scale fermentations that modelled the sourdough fermentation step used in rye baking. Total folate contents were determined using Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism. The microorganisms studied did not excrete folates into the media in significant amounts. Yeasts increased the folate contents of sterilised rye flour-water mixtures from 6.5 microg/100 g to between 15 and 23 microg/100 g after 19-h fermentation, whereas lactic acid bacteria decreased it to between 2.9 and 4.2 microg/100 g. Strains of Lactobacillus bulgaricus, L. casei, L. curvatus, L. fermentum, L. helveticus, Pediococcus spp., and Streptococcus thermophilus that were also tested gave folate contents after fermentation that varied between 2 and 10.4 microg/100 g. Although the four Lactobacillus spp. from sourdough consumed folates their effect on folate contents in co-cultivations was minimal. It was concluded that the increase of folate content during fermentation was mainly due to folate synthesis by yeasts. Fermentation of non-sterilised flour-water mixtures as such resulted in three-fold increases in the folate contents. Two folate producing bacteria were isolated from the non-sterilised flour and identified as Enterobacter cowanii and Pantoea agglomerans.     

The prevalence of Clostridium botulinum in European river lamprey (Lampetra fluviatilis) in Finland

The prevalence of Clostridium botulinum types A, B, E and F in river lampreys caught in Finnish rivers was determined for the first time using a quantitative PCR-MPN (most probable number) analysis. One of 67 raw whole lampreys (1.5%) was positive for the botulinum neurotoxin type E gene, with the estimated C. botulinum count being 100spores/kg. Two type E strains were isolated from the positive sample and confirmed as different genotypes by pulsed-field gel electrophoresis. Although the current procedure of bringing the charcoal-broiled lampreys to market has been without any further packaging or extended storage, interest towards increasing the shelf life of the product by vacuum-packaging is increasing. Our results demonstrate that C. botulinum type E may constitute a safety hazard in processed lampreys from the Baltic Sea area if packaging and extended shelf lives are to be used. To control the potential risk, a storage temperature of 3 degrees C or below should be recommended for these products.     

Prevalence and genetic characterization of Listeria monocytogenes in retail broiler meat in Estonia

The prevalence and genetic diversity of Listeria monocytogenes in raw broiler legs at the retail level in Estonia were studied. A total of 240 raw broiler legs (120 from Estonia and 120 of foreign origin, which had been imported to Estonia from Denmark, Finland, Hungary, Sweden, and the United States) from 12 retail stores in the two largest cities in Estonia (Tallinn and Tartu) were investigated from January to December 2002. Of these, 70% were positive for L. monocytogenes. The prevalence of L. monocytogenes in broiler legs of Estonian origin (88%) was significantly higher than in broiler legs of foreign origin (53%) (P < 0.001). Altogether, 169 (106 Estonian and 63 imported) L. monocytogenes isolates were characterized by pulsed-field gel electrophoresis (PFGE) typing after treatment with the restriction enzyme AscI. The isolates showed a wide genetic diversity, with 35 different PFGE types obtained. Of these, 11 PFGE types came only from isolates of broiler legs of Estonian origin, 4 of Danish origin, 2 of Finnish origin, and 4 of Hungarian origin. Fourteen PFGE types came from isolates of broiler legs that originated from various countries. The strains that shared the same PFGE types from isolates of Estonian origin were recovered from broiler legs that came from different stores over the course of several months. Seventy-one L. monocytogenes isolates, including all PFGE types, were serotyped, and three serotypes (1/2a, 1/2b, and 4b) were obtained. Serotype 1/2a accounted for 96% of the isolates.