New thermostable copolymers for holographic storage based on methylmethacrylate with methacrylamide or methacrylic acid

Two new copolymers based on methylmethacrylate (MMA) with methacrylamide (MAA) and methacrylic acid (MA) containing distributed phenanthrenequinone (PQ) molecules are fabricated for the purpose of optical recording by generating holographic diffractive structures under argon laser illumination. Chemical conditions for the formation of holograms are discussed and confirmed by the spectral characteristics of the material. Thermal and adhesive properties were improved with the aim of expanding the range of polymer application and generating of diffractive elements with long term stability and high optical quality.     

Occurrence of ochratoxin A producing fungi in wine and table grapes in Israel

A 3-year survey was conducted to assay the number of Aspergillus Section Nigri isolates and in vitro ochratoxin A (OTA) production capacity in 10 vineyards in Israel. The survey included field sampling of two wine cultivars, 'Sauvignon Blanc' and 'Cabernet Sauvignon' as well as the table grape cultivar 'Superior'. A total of 2114 isolates were analyzed and of those 161 isolates were shown to produce OTA. The major finding was that Aspergillus carbonarius (336 tested strains) is the most consistent producer of OTA, with approximately 35% of the isolates identified as positive in vitro. In comparison, 3.1% of other isolates from the Aspergillus niger aggregate (of 1432 strains) produced OTA in vitro. In contrast, none of the 346 tested strains with a uniseriate head morphology produced OTA. The incidence of infected berries was very low before veraison, while at harvest, this frequency was twice as high. In general, the composition of black Aspergilli did not differ during berry development. Generally, more OTA-producing isolates were isolated from the surface of table grapes cv. 'Superior' compared to 'Sauvignon Blanc'. None of the samples collected at harvest contained traces of OTA in the juice. This study shows that grapes in Israel are contaminated with ochratoxigenic species which represent a risk of OTA contamination.     

The effect of metal type on the sulfur tolerance of catalysts supported on niobia for sour water-gas shift reaction

Hydrogen production via water-gas shift (WGS) reaction using heavy oil residues as syngas source is an attractive way to improve refinery margin. However, this low cost syngas may present significant concentration of sulfur, leading to poisoning of usual WGS catalysts. Searching for sulfur tolerant catalysts, the performance of niobia supported platinum, gold and copper catalysts was evaluated under near-industrial conditions, in the absence and presence of H₂S. Cu/Nb₂O₅ catalyst was inactive, even under clean conditions. Au/Nb₂O₅ presented higher activity and complete deactivation when exposed to sulfur, but recovered its catalytic activity with the removal of H₂S from the reaction mixture, indicating a reversible deactivation. Pt/Nb₂O₅ catalyst was the most suitable among the catalysts evaluated to be used in sour conditions, not deactivating when exposed to 50 ppm and 1000 ppm of H₂S.     

Sensitive enzyme immunoassay for screening methandienone in dietary supplements

Methandienone is a synthetic exogenous steroid which, like other anabolic steroids, is strictly regulated in many countries. In recent years, increasing numbers have been detected of illegal additions into dietary supplements of methandienone and other anabolic androgenic steroids (AAS). In this work, a competitive indirect enzyme-linked immunosorbent assay (ELISA) has been constructed for the detection of methandienone using an antiserum against methandienone. Under optimal experimental conditions, the ELISA achieved a limit of detection of 0.04 ± 0.01 µg.g^?1. The obtained intra- and inter-day coefficients of variation were less than 8%. The developed ELISA was applied in the analysis of real dietary supplement samples. To minimise the effect of the sample matrix, the sample extracts were simply diluted before addition into the immunoassay. The achieved recovery values were around 100%. Results obtained from the ELISA correlated well, both in terms of accuracy and precision, with those obtained by UHPLC-MS/MS (reference method). The presented ELISA could be successfully applied for the simple screening of dietary supplements.     

Isothermal vapour–liquid equilibria for the ethanol–n-octane system

A modified Dvorák & Boublík & recirculation still was used for the determination of isothermal vapour–liquid equilibrium data for the binary system ethanol–n-octane at four temperatures. Liquid activity coefficients, γ, were evaluated, and log γ values were correlated by a three-constant Redlich–Kister equation. Binary azeotrope exists at all four temperatures and the mole fraction of ethanol in the azeotrope increases with increasing temperature.     

Measures of Diversity in Classifier Ensembles and Their Relationship with the Ensemble Accuracy

Diversity among the members of a team of classifiers is deemed to be a key issue in classifier combination. However, measuring diversity is not straightforward because there is no generally accepted formal definition. We have found and studied ten statistics which can measure diversity among binary classifier outputs (correct or incorrect vote for the class label): four averaged pairwise measures (the Q statistic, the correlation, the disagreement and the double fault) and six non-pairwise measures (the entropy of the votes, the difficulty index, the Kohavi-Wolpert variance, the interrater agreement, the generalized diversity, and the coincident failure diversity). Four experiments have been designed to examine the relationship between the accuracy of the team and the measures of diversity, and among the measures themselves. Although there are proven connections between diversity and accuracy in some special cases, our results raise some doubts about the usefulness of diversity measures in building classifier ensembles in real-life pattern recognition problems.     

Can apomyoglobin form a complex with a spherical ligand? Interactions between apomyoglobin and [C60] fullerene derivative

The preparation and characterization of the stable equine skeletal muscle apomyoglobin and eee-isomer of tris-malonic acid [C60] fullerene complex is reported. For this new bio-nanomaterial preparation, a procedure of complexation-during-protein-refolding was used and the obtained compound sustained separation by gel-filtration and ion-exchange chromatography. The apomyoglobin-tris-malonic acid [C60] fullerene complex was characterized by UV-vis spectroscopy, steady state fluorescence, time-resolved fluorescence, and circular dichroism spectroscopies. Important information provided by this study, regarding the stability and properties of new material, may lead to a better understanding of the apomyoglobin protein binding characteristics, as well as to development of novel antioxidant and photodynamic therapeutic agents and components for bioelectronic devices.     

Modeling elastic behavior of compressed rock samples in the pre-failure zone

The experimental results are presented for deformation of rock samples in the pre-failure zone under compression. Anomalous periodic character of change in strains is established. An elastic solution to the corresponding problem on the anomalous behavior of rock samples is found, and the experimental databased phenomenological parameters of the model are determined. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 3–13, November–December, 2005.