Development of a colloidal gold-based lateral-flow immunoassay for the rapid simultaneous detection of zearalenone and deoxynivalenol

A multianalyte lateral-flow technique using colloidal gold-labeled monoclonal antibodies was developed for the rapid simultaneous detection of deoxynivalenol (DON) and zearalenone (ZEA). The results of this qualitative one-step test were interpreted visually. A very simple and fast sample preparation was used, and the assay procedure could be accomplished within 10 min. When applied to spiked wheat samples, the technique gave accurate and reproducible results. Cut-off levels of 1500 and 100 μg kg⁻¹ for DON and ZEA, respectively, were observed. The described multianalyte format can be used as a reliable, rapid and cost-effective on-site screening technique for the simultaneous determination of mycotoxins in grain samples.     

A study of cryostructuring of polymer systems. 34. Poly(vinyl alcohol) composite cryogels filled with microparticles of polymer dispersion

Macroporous filled and unfilled poly(vinyl alcohol) (PVA) cryogels are produced by cryogenic treatment (freezing at ?20°C for 12 h followed by thawing at a rate of 0.03°C/min) of mixtures of an aqueous PVA solution and a full-component poly(vinyl acetate) (PVAc) dispersion or its individual components. The values of the elasticity modulus and fusion temperature are determined for obtained samples; their microstructure is studied by light microscopy of thin sections. It is shown that the effects that are induced by the incorporation of PVAc dispersion into the macroporous matrix of the PVA cryogel are due to the presence of both a discrete phase, i.e., solid PVAc microparticles, and ingredients of the liquid phase of the PVAc dispersion, mainly, urea. Therewith, the dispersed particles themselves serve as a reinforcing filler, i.e., increase the rigidity and (to a lesser extent) heat endurance of the cryogel, while urea, which possesses chaotropic properties and hinders the intermolecular hydrogen bonding of PVA chains, reduces the rigidity and heat endurance of the composites. As a result, the total effect is determined by the competition of differently directed influences of these components of PVAc dispersion and depends on its concentration in the resulting filled cryogel. It is also shown that PVAc microparticles are mainly entrapped in the gel phase of the macroporous matrix and form necklacelike aggregates, the cross-sectional areas and lengths of which depend on the degree of composite filling.     

Assessment of Combined Therapy of Histochrome and Nebivalol as Angioprotectors on the Background of Experimental Hypertension by Magnetic Resonance Angiography

The renovascular model of arterial hypertension (AH) was induced in Wistar and OXYS strains. The model of AH was verified by magnetic resonance angiography. It was shown that histochrome enhances the vasodilatory effect of selective beta1 blocker, nebivalol, against cerebral and renal arteries using a combined therapy in this model. Monotherapy with histochrome had no significant effect on blood pressure. The angioprotective effect of histochrome in the combined therapy was significantly more expressed in hypertensive OXYS rats compared to hypertensive Wistar rats as shown by magnetic resonance imaging (MRI) morphometry. These differences were more observable in the intrarenal part of renal arteries. The degree of regional discirculation of arteries was calculated by the Cerebro-Renal Vascular Index, which confirms the therapeutic advantage of combined therapy with histochrome and nebivalol in the background of AH. Thus, comparative MRI angiography and MRI morphometry of the cerebral and renal arteries in hypertensive Wistar and OXYS strain rats showed that histochrome expands the therapeutic potential of nebivalol due to angioprotective effects in the vascular region of the target organs.     

Effect of the topology of benzotriazole derivatives on their chromatographic retention under RP-HPLC conditions

Sixth order connectivity indices are calculated for 29 benzotriazole derivatives. Correlations between the connectivity indices, physicochemical characteristics, and retention factors of the mentioned compounds are obtained for reversed-phase high-performance liquid chromatography conditions. Based on the correlations obtained, a predictive calculation of the retention factors of some benzotriazole derivatives is performed.     

Thermodynamic properties of liquid Cu-Ni-Co-Fe alloys

Data on boundary binary systems in conjunction with geometric models and the Redlich-Kister method were used to calculate the integral thermodynamic characteristics and the activities of the components for liquid Cu-Ni-Co-Fe alloys at 1600°C.     

Lateral-flow colloidal gold-based immunoassay for the rapid detection of deoxynivalenol with two indicator ranges

A lateral-flow immunoassay using a colloidal gold-labelled monoclonal antibody was developed for the rapid detection of deoxynivalenol (DON). Different parameters, such as the amount of immunoreagents, type of the materials, composition of the blocking solution and of the detector reagent mixture, were investigated to provide the optimum assay performance. The experimental results demonstrated that such a visual test had an indicator range rather than a cut-off value. Thus, tests for DON determination with two different indicator ranges of 250-500 and 1000-2000 μg kg⁻¹ were designed. The method allowed detection of DON at low and high concentration levels, which could be useful for research and practical purposes. The assay applied to spiked wheat and pig feed samples demonstrated accurate and reproducible results. The applicability of the developed lateral-flow test was also confirmed under real field conditions. The test strips prepared in Belgium were sent to Mexico, where they were used for the screening of DON contamination in different bread wheat entries from Fusarium Head Blight inoculated plots. The results were compared with those obtained by ELISA and LC-MS/MS. A poor correlation between ELISA and LC-MS/MS was observed. Visual results of the dipstick tests were in a good agreement with the results of the LC-MS/MS method. Coupled with a simple and fast sample preparation, this qualitative one-step test based on the visual evaluation of results did not require any equipment. Results could be obtained within 10 min. The described assay format can be used as a simple, rapid, cost-effective and robust on-site screening tool for mycotoxin contamination in different agricultural commodities.     

Spectroscopic characterization of the chemical composition of the potent sweetener Vartamil

The chemical composition of the potent sweetener Vartamil was characterized using spectral methods. It was demonstrated that Vartamil is a mixture of saccharose chloro derivatives, the main one of which is 4,1′,6′-trichloro-4,1′,6′-trideoxygalactosaccharose (Sucralose). __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 159–163, March–April, 2008.