1,721,041 research outputs found
Occurrence of Bisphenol A and its analogues in some foodstuff marketed in Europe
No full textBisphenol A and its analogues belong to the class of endocrine disrupting chemicals, massively employed by industries to produce polycarbonate and epoxy resins, designed to be in direct contact with foodstuffs. Their leaching from the canned packaging into its content results in food contamination. This review aims at offering a country-specific overview of the occurrence of bisphenols in six main categories of foodstuff marketed in the EU, based on monitoring studies performed in the 27 EU countries for which data are available and prevalently published in the last five years.
The general overview of the literature data shows that concentration values of BPs detected into foodstuff is lower in Northern Europe than Southern Europe. A probable daily intake was hypothesized for some countries to provide an EU population exposure assessment. The consumption of canned meat and vegetables is responsible of PDI values higher than those of other food categories. These data emphasize that food and beverage monitoring should deserve greater attention especially by European countries for which no studies are available and especially with regards to bisphenols other than BPA whose limits are not set by the European regulations and whose toxicity has not been fully established
Tamoxifen as an emerging endocrine disruptor. Effects on fish reproduction and detoxification target genes
Full text linkEnzyme distribution and secondary structure of sol-gel immobilized glucose oxidase by micro-attenuated total reflection FT-IR spectroscopy
No full textGlucose oxidase (GOD) immobilized into sol-gel matrices was studied by using Micro-Attenuated Total Reflection Fourier Transform Infrared (micro-ATR FT-IR) spectroscopy in order to characterize enzyme distribution and secondary structure in systems with valuable potentialities in amperometric and optical biosensing. Spectra were acquired in the 4000-600 cm - 1 frequency region and the analysis of specific fingerprints in the FT-IR spectra evidenced that the enzyme was actually immobilized in the matrix. The enzyme spatial distribution was obtained by examining the amide I and amide II band region of spectra from defined sample positions. The deconvolution of the amide I band in terms of lorentzian functions provided information on the secondary structure of the immobilized GOD. By this approach a macroscopic preservation of GOD activity upon immobilization was evidenced along with the existence of some matrix sites with locally inactivated GOD. To our knowledge this is the first example of point-by-point characterization of conformational changes of immobilized enzyme by means of micro-ATR infrared spectroscopy, thus confirming that this technique can be usefully employed for a non- or minimally-invasive detailed micro-characterization of catalytic supports in order to improve their functionalit
Enzyme distribution and secondary structure of sol–gel immobilized glucose oxidase by micro-attenuated total reflection FT-IR spectroscopy
No full textEffect of molecular confinement on internal enzyme dynamics: frequency domain fluorometry and molecular dynamics simulation studies.
No full textAdvantages in using non-isothermal bioreactors in bioremediation of water polluted by phenol by means of immobilized laccase from Rhus vernicifera
No full textLaccase from Rhus vernicifera was immobilized on a polypropylene membrane chemically modified with
chromic acid. Ethylenediamine and glutaraldehyde were used as spacer and bifunctional coupling agent,
respectively. Phenol was used as substrate.
To know how the immobilization procedures affected the enzyme reaction rate the catalytic behavior
of soluble and insoluble laccase was studied under isothermal conditions as a function of pH, temperature
and substrate concentration. From these studies, two main singularities emerged: (i) the narrower
pH–activity profile of the soluble enzyme in comparison to that of the insoluble counterpart and (ii) the
increase in pH and thermal stability of the insoluble enzyme.
The laccase catalytic behaviorwas also studied in a non-isothermal bioreactor as a function of substrate
concentration and size of the applied transmembrane temperature difference. It was found that, under
non-isothermal conditions and keeping constant the average temperature of the bioreactor, the enzyme
reaction rate linearly increased with the increase of the temperature difference
Investigation on clarified fruit juice composition by using visible light micro-Raman spectroscopy
No full textLiquid samples of clarified apple and apricot juices at different production stages were investigated using visible light micro-Raman spectroscopy in order to assess its potential in monitoring fruit juice production. As is well-known, pectin plays a strategic role in the production of clarified juice and the possibility of using Raman for its detection during production was therefore evaluated. The data analysis has enabled the clear identification of pectin. In particular, Raman spectra of apple juice samples from washed and crushed fruits revealed a peak at 845 cm-1 (typical of pectin) which disappears in the Raman spectra of depectinised samples. The fructose content was also revealed by the presence of four peaks at 823 cm-1, 872 cm-1, 918 cm-1 and 975 cm-1. In the case of apricot juice, several Raman fingerprints of β-carotene at 1008, 1159 and 1520 cm-1 were also highlighted. Present results resulted interesting for the exclusive use of optical methods for the quantitative determination of the above-mentioned substances in place of the biochemical assays generally used for this purpose, which are time consuming and require different chemical reagents for each of them. © 2007 by MDPI
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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