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Rijeka, Croatia

In the present study were conducted the effect of pH (5.5, 6.0 and 6.5) and concentration of new synthesized 3-/2-aminophenylimino-(p-toluoyl)/-4-hydroxy-6-(p-tolyl)-2H-pyrane-2-one (Schiff base) on decrease the concentration of aflatoxin M 1 (AFM 1) in raw milk contaminated with known concentration of this toxin. Experiments were carried out at temperature of 4 °C during 35 days. At pH 5.5 Schiff base concentration of 0.1 μmol/L was lessening the concentration of AFM 1 after 35 days by 55%. However, at pH 6.5 the most effective concentration for lessening of AFM 1 was 0.5 μmol/L. a at pH value of 7 or higher. The ability of Schiff base to act as antimycotoxigenic agent provides new perspective for possibly using this compound to control AFM 1 contamination in milk and to extent shelf lives of this food. Detection of toxicity of investigated Schiff base was performed by using the brine shrimp (Artemia salina) larvae as an biological indicator to determine their sensitivity to this chemical agent.

Durakovic L.,University of Zagreb | Blazinkov M.,University of Zagreb | Seol B.,University of Zagreb | Tudic A.,Croatian Waters | And 6 more authors.
Agriculturae Conspectus Scientificus | Year: 2010

The eff ect of newly synthesized derivative of 11-hydroxy-7-imino-7H-7a, 12-diazabenzo/a/anthracen- 6-one, on growth and afl atoxin B1 and G1 (AFB1 and AFG1) accumulation by toxigenic mould Aspergillus fl avus ATCC 26949 was studied on a solid substrate (maize grains) to determine the possible use of this compound as a mean of controlling afl atoxin accumulation. Experiments were carried out in a stationary culture at temperature of 28°C during 21 days. The growth of mould was monitored by measuring the analysis of chitin as glucosamine, as a criterion, and concentration of AFB1 and AFG1 was measured by HPLC method using Hewlett-Packard instrument with fl ourescence detector. Concentration of investigated coumarine of 0.05 mmol x g-1 stimulated mould growth and afl atoxin accumulation, but concentration of 0.2 mmol x g-1 or higher produced an inhibitory eff ect. In the presence of 0.2 and 0.5 mmol x g-1 of this compound, mould growth was decreased by 22% and 65%, respectively. Concentration of AFB1 in these investigations was reduced by 30% and 90%, and concentration of AFG1 was reduced almost completely in respect to values obtained in control experiments. In experiments with 2.0 mmol x g-1 of this inhibitor no synthesis of both investigated afl atoxins was found in the sample although small increment of biomass was detected.

Benac C.,University of Rijeka | Dugonjic S.,University of Rijeka | Arbanas Z.,University of Rijeka | Arbanas Z.,Institut IGH d.d. | And 2 more authors.
Rock Engineering in Difficult Ground Conditions - Soft Rocks and Karst - Proceedings of the Regional Symposium of the International Society for Rock Mechanics, EUROCK 2009 | Year: 2010

This paper presents the origin and the type of instability phenomena in the Rječina and Sušačka draga valleys near the town Rijeka, Croatia. Both locations are part of unique morphostructural unit. Karstified carbonate rocks prevail in this area. Paleogene siliciclastic sedimentary rock complex, i.e. flysch, has a form of a squeezed syncline between carbonate rocks. Geological boundaries between carbonate and flysch rock mass are tectonic, but with different mechanism of origin. Erosion processes and gravitational forces have caused disintegration of the carbonate rock mass, separation of blocks and their sliding over the flysch bedrock, as well as the accumulation of talus on the toe of rocky scarps. During the time, coarse grained fragments originating from the rockfalls were mixed with soil-like material from flysch weathered zone. Disintegration of carbonate scarps, rockfall and talus displacements are a permanent phenomena. The comparisons of a recent instability show a distinction between Rječina and Sušačka draga valleys. © 2010 Taylor & Francis Group, London.

Glavas Z.,University of Zagreb | Strkalj A.,University of Zagreb | Maldini K.,Croatian Waters
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science | Year: 2016

Effects of Sb additions on the graphite morphology of ductile iron castings in different wall thicknesses (3, 12, 25, 38, 50, 75, and 100 mm) were analyzed in this paper. In the wall thicknesses of 3, 12, and 25 mm, low contents of rare earth (RE) elements showed a beneficial effect on nodule count and nodularity. Nodularity >80 pct and a high nodule count were achieved without the addition of Sb. In the wall thicknesses of 38, 50, 75, and 100 mm, nodularity >80 pct was not achieved without the use of the chill or proper content of Sb. Excess of RE elements was neutralized with the addition of proper amount of Sb to the wall thickness. Addition of 0.01 wt pct Sb (ratio of RE/Sb = 0.34, ratio of RE/SE = 0.105) was sufficient to achieve nodularity >80 pct in the wall thicknesses of 38, 50, 75, and 100 mm. © 2016 The Minerals, Metals & Materials Society and ASM International

Schymanski E.L.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Singer H.P.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Slobodnik J.,R.O.S.A. | Ipolyi I.M.,R.O.S.A. | And 25 more authors.
Analytical and Bioanalytical Chemistry | Year: 2015

In this article, a dataset from a collaborative non-target screening trial organised by the NORMAN Association is used to review the state-of-the-art and discuss future perspectives of non-target screening using high-resolution mass spectrometry in water analysis. A total of 18 institutes from 12 European countries analysed an extract of the same water sample collected from the River Danube with either one or both of liquid and gas chromatography coupled with mass spectrometry detection. This article focuses mainly on the use of high resolution screening techniques with target, suspect, and non-target workflows to identify substances in environmental samples. Specific examples are given to emphasise major challenges including isobaric and co-eluting substances, dependence on target and suspect lists, formula assignment, the use of retention information, and the confidence of identification. Approaches and methods applicable to unit resolution data are also discussed. Although most substances were identified using high resolution data with target and suspect-screening approaches, some participants proposed tentative non-target identifications. This comprehensive dataset revealed that non-target analytical techniques are already substantially harmonised between the participants, but the data processing remains time-consuming. Although the objective of a “fully-automated identification workflow” remains elusive in the short term, important steps in this direction have been taken, exemplified by the growing popularity of suspect screening approaches. Major recommendations to improve non-target screening include better integration and connection of desired features into software packages, the exchange of target and suspect lists, and the contribution of more spectra from standard substances into (openly accessible) databases. [Figure not available: see fulltext.] © 2015 Springer-Verlag Berlin Heidelberg

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