Veterinary drug residues determination in raw milk in Croatia

A total of 1259 raw milk samples were examined over a three-year period for various antibiotics chloramphenicol, penicillins, cephalosporines, tetracyclines, sulfonamides, beta-lactams, quinolones, aminoglycosides and macrolides. Microbiological and immunoassay methods used for determination of these antibiotics were validated according to the guidelines laid down by European Commission Decision 2002/657/EC. Microbiological screening detected 36 positive samples and in only one sample presence of residues was confirmed. Also, immunoassay determination found one positive sample on tetracycline residues. In total, 37 positive samples were determined, which was equal to a frequency of 0.69% of the total number of targeted analyses. The HPLC-DAD method confirmed the presence of residues above the maximum residue limits (MRLs) in two samples with concentrations of 12 μg kg^?1 for penicillin G and 19 μg kg^?1 for amoxicillin, and 1671 μg kg^?1 for tetracycline. Calculated estimated daily intakes (EDIs) for antibiotics presented showed lower exposure levels than the fixed values of acceptable daily intakes (ADIs). These suggested that raw milk in Croatia contain very low levels of veterinary drugs so that toxicological risk with regard to consuming of milk could not be considered as a public health problem.     

Modified quadratic loss function for a trivariate response with the exact feasible region for parameters

This paper deals with modification of Taguchi's quadratic quality loss function (QQLF) for a trivariate responses, each having a NtB (nominal-the-best) type quality characteristic and correlated in pairs. It tends to improve and extend results obtained in 0025 and 0035. Impossibility to solve nonlinear constraint in [6] resulted in an approximate algorithm to determine unknown parameters of QQLF. Here the nonlinear constraint is solved analytically and consequently the exact feasible region is obtained. The QQLF is formed by means of the parameters from the restrictive feasible region and proved suitable for all the types of correlation among quality characteristics.     

Synthesis,characterization, and antimicrobial activity of poly(GMA-co-EGDMA) polymer decorated with silver nanoparticles

Composite consisting of silver nanoparticles coordinated to poly(GMA-co-EGDMA) macroporous copolymer was prepared by attachment of amino group to the poly(GMA-co-EGDMA) in the reaction with ethylene diamine, and consequent reduction of silver ions with amino groups at elevated temperature. The infrared measurements indicated that surface of silver nanoparticles is passivated through the coordination of the lone pair on the N atom of the imine present in the skeleton of the poly(GMA-co-EGDMA) copolymer. The inductively coupled plasma atomic emission, UV–Vis reflection spectroscopy, X-ray diffraction, and transmission electron microscopy measurements revealed the high content (52 wt%) of well-separated silver nanoparticles in the size range of 5–10 nm onto composite. Antimicrobial efficiency of composite was tested against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus, and fungus C. albicans in wide concentration range of composite. The composite ensured almost maximum reduction of both bacteria, while the fungi reduction reached 96.5 %.     

On the tungsten carbide synthesis for PEM fuel cell application – Problems,challenges and advantages

Fuel cell application of tungsten carbide is revisited starting with four different tungsten carbide precursors used for high temperature synthesis. It was shown that the final products greatly depend on the nature of the precursor. Using tungsten peroxide/2-propanol derived precursor almost pure WC was obtained which was subjected to further electrochemical investigation. It was shown that it is necessary to decorate WC with Pt nanoparticles in order to obtain satisfactory fuel cell performance, but catalytic activity of Pt/WC anode catalyst is not expected to overcome the activity of Pt/C. It is argued that new synthetic routes for the preparation of WC should be directed towards obtaining highly dispersed WC, that is, WC with high external surface area available for Pt deposition, rather than high specific surface area WC with large contribution of micropores having no importance when it comes to the use of WC as a catalyst support. The true benefit of the use of WC as catalyst support is found in increased CO tolerance/CO oxidation activity of WC-supported Pt catalysts. Qualitative mechanistic view on increased CO oxidation activity of Pt/WC is offered.     

3D reinforcement of stiffener-to-skin T-joints by Z-pinning and tufting

Carbon fibre/epoxy T-stiffener-to-skin joint was reinforced through the thickness, either by insertion of Z-Fiber^® before autoclave cure of prepreg or by tufting of dry preform with a glass thread before resin injection and cure. The joints pull-off resistance increased significantly for both types of T-joints under both quasi-static and fatigue loading conditions. In the case of the tufted joints, the delamination between the skin and the stiffener stopped completely and the samples failed in bending. It is shown that a finite element model is successful in reproducing qualitatively the cracking progression in the unreinforced and 3D reinforced T-joint provided that the action of the through-the-thickness reinforcement is modelled by discrete nodal forced placed so as to replicate the physical reality.     

A concept for inferring ‘frontier research’ in grant proposals

This paper discusses a concept for inferring attributes of ‘frontier research’ in peer-reviewed research proposals under the popular scheme of the European Research Council (ERC). The concept serves two purposes: firstly to conceptualize, define and operationalize in scientometric terms attributes of frontier research; and secondly to build and compare outcomes of a statistical model with the review decision in order to obtain further insight and reflect upon the influence of frontier research in the peer-review process. To this end, indicators across scientific disciplines and in accord with the strategic definition of frontier research by the ERC are elaborated, exploiting textual proposal information and other scientometric data of grant applicants. Subsequently, a suitable model is formulated to measure ex-post the influence of attributes of frontier research on the decision probability of a proposal to be accepted. We present first empirical data as proof of concept for inferring frontier research in grant proposals. Ultimately the concept is aiming at advancing the methodology to deliver signals for monitoring the effectiveness of peer-review processes.     

Epithermal neutron activation analysis of Cr(VI)-reducer basalt-inhabiting bacteria

Epithermal neutron activation analysis (ENAA) has been applied to study elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance, demonstrating that the bacteria differ in their rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(V) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 microg/g of dry weight) indicate bacterial adaptation to the environmental conditions typical of the basalts. The concentrations of at least 12-19 different elements were determined in each type of bacteria simultaneously starting with the major to ultratrace elements. The range of concentrations spans over 8 orders of magnitude.