Small diameter tubular structure design using solvent‐free textile techniques

The aim of research was to elaborate the non‐biodegradable (made of polypropylene (PP)) and resorbable (made of polylactide (PLA)) tubular fibrous structures for the reconstruction of the vascular vessels. For the mentioned structures design, nonconventional manufacturing techniques such as melt blown, melt electrospinning, and melt electroblowing were used. Three techniques were chosen as methods allowing on the fibrous structures manufacture containing fibers in nano‐ or submicro‐size diameter. Other advantages of free‐solvent technique use is the reduction in the clinical adverse events associated with solvent resided in the fibrous structure during the fabrication. The tubular fibrous structures of PP and PLA using above‐mentioned techniques were designed. In first stage, the analysis of the processing parameters influence on the nonbiodegradable and biodegradable tubular structures fiber diameter was performed. Subsequently, the validation step was the analysis of the influence of processing parameters on PP and PLA structural properties for each manufacturing techniques was investigated. The research results confirmed the ability of the tubular structures manufacture with various fiber diameter depending on the applied technique and processing parameters. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40147.     

Elaboration of small‐diameter vascular prostheses—Selection of appropriate sterilisation method

The aim of study is the elaboration of semi‐biodegradable, multilayered tubular structures as substitutes for the reconstruction of small diameter vascular prostheses (<6 mm). The inert external layer of the prostheses will be fabricated via the melt electrospinning of poly (l ‐lactide‐co‐glycolide) (PLGA). The middle layer will be constructed from polypropylene (PP); the first prototype will be produced via melt electrospinning and the second using the melt blowing technique. The general aim of this stage of the research is the selection of a sterilisation technique that is appropriate for semi‐biodegradable, multilayered tubular structures. For this purpose, single tubular structures created via the melt electrospinning of PLGA or PP and melt blown tubular structures of PP were elaborated. The influence of steam, ethylene‐oxide (EO), and radiation sterilisation techniques on the elaborated microstructure of tubular structures was analyzed during this study. The effect of each sterilisation technique was evaluated using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy/energy‐dispersive X‐ray spectroscopy analysis (SEM/EDS). The changes in average molecular weight (M_w) and crystallinity index (CI) of the PLGA tubular structures after EO and steam sterilisation were evaluated. The EO and steam sterilisation resulted in the complete destruction of PLGA tubular structures. Only the radiation sterilisation (accelerated electrons) did not influence on PLGA tubular structures morphology as well as thermal and chemical properties. FTIR and SEM/EDS analysis indicated that no changes in the chemical properties of PP tubular structures after each sterilisation occurred. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40812.     

Operando Raman–GC studies of alumina-supported Sb-V-O catalysts and role of the preparation method

The interactions between Sb and V are studied by operando Raman–GC methodology during propane ammoxidation in order to understand the effect of the preparation method and reaction conditions on the structure and activity/selectivity of alumina-supported Sb-V-O catalysts. Dispersed V(V) species react with antimony species during propane ammoxidation to form VSbO₄; partially reversible transformations towards surface vanadium (V) species may account for the catalytic redox cycle. The catalytic performance is determined by the interaction between Sb and V, which is affected by the preparation method and the reaction conditions.     

Defuzzification as a special way of dealing with retranslation

The problem of defuzzification is examined in this paper from a broader perspective as a special way of dealing with the general problem of retranslation. The paper includes an overview of different formulations of the problem of defuzzification, as well as an overview of methods that have been suggested in the literature for dealing with the problem. Our own approach to defuzzification, which is described in the paper in more details, is based on relevant measures of uncertainty-based information. This paper is a companion to our recent paper that addresses the general problem of retranslation in computing with perceptions (Martin and Klir 2006).     

Size and shape influence of luminescent orthovanadate nanoparticles on their accumulation in nuclear compartments of rat hepatocytes

In this paper the process of nonfunctionalized negatively charged orthovanadate nanoparticle accumulation and redistribution in cells dependent on their shape and size was investigated. Aqueous colloidal solutions of nReVO₄:Eu^3 + (Re = Gd, Y, La) luminescent nanocrystals of different sizes and shapes have been synthesized. The average sizes of spherical particles were 2, 20, and 300 nm, of spindle-like particles – 22 × 6.3 nm, and of rod-like particles – 57 × 4.4 nm. Luminescence of nReVO₄:Eu^3 + nanocrystals was effectively excited by UV and visible irradiation. By means of luminescence microscopy and luminescence microspectroscopy, it has been revealed that spherical nanocrystals with an average diameter of 2 nm tend to accumulate mainly in the rat hepatocyte nuclei in situ and also in the isolated nuclei of these cells. An additional experiment has shown that nanoparticles reveal tropism to nuclear structural components. The penetration into nuclei does not require any modifications of the surface of nanoparticle and is governed by the shape and size of nanoparticle and also is determined by the cellular type.     

Curcumin antifungal and antioxidant activities are increased in the presence of ascorbic acid

The objective of this study was to evaluate the antifungal and antioxidant activities of curcumin, ascorbic acid and the mixture of these two compounds. For the antifungal assay, the minimum inhibitory concentrations (MIC) were determined using Candida strains (ATCC and clinical isolates). Curcumin alone inhibited growth of Candida albicans yeast cells, whereas ascorbic acid did not present effects. However, when the mixture of ascorbic acid and curcumin was assayed to determine the association of the two compounds, the curcumin MIC decreased 5- to 10-fold. In the antioxidant assays, the sum of the alone activities of curcumin and ascorbic acid were lower than the activity of the two-compound mixture. This study highlights the importance of the association between two common antioxidants in foods, to improve the antifungal and antioxidant activities of curcumin (in vitro), and can be applied to Candida spp. infection and diseases associated with oxidative stress.     

The Composition of Mixed Micelles Formed by Dodecyl Trimethyl Ammonium Bromide and Benzethonium Chloride in Water

The composition of the mixed micelles formed by benzethonium chloride and dodecyl trimethyl ammonium bromide in water were experimentally determined by a combination of surfactant ion-selective electrodes and UV–Vis spectroscopy measurements. Results were compared with the computed compositions from three theories on mixed micelles available in the literature (Regular Solution, Motomura’ and Georgiev’s). The basis of the Junquera and Aicart method and the determination of the micelle aggregation number (N) by pyrene fluorescence quenching, i.e., the constancy of N and the mixed micelle composition when the total concentration is changed, were not supported by our experimental results. Experimental micelle compositions were statistically equal to those computed by Regular Solution Theory. The mixed micelle composition and the quantity of non-micellized surfactant molecules change with concentration above the critical micelle concentration, and therefore do not support the assumptions used in the Junquera and Aicart procedure and in the determination of N by pyrene fluorescence quenching. The reason why the latter procedure gives N values similar to those obtained from other techniques is discussed.     

Microbiological shelf life and sensory evaluation of fruit juices treated by high-intensity pulsed electric fields and antimicrobials

The effect of combining high-intensity pulsed electric fields (HIPEF) with citric acid or cinnamon bark oil, as antimicrobial substances, on the microbiological shelf life of strawberry, orange, apple, pear and tomato juices was evaluated in addition to the sensory properties of these products. An extension of the microbiological shelf life of fruit juices treated by HIPEF with or without antimicrobial substances was observed in comparison with those juices without processing. Naturally occurring microorganisms in the juices were inactivated by HIPEF treatment. Among the HIPEF treated juices, those from strawberry and orange did not show microbial growth along the 91 days of storage at 5 °C. However, resident microbial populations in apple, pear and tomato juices only were controlled during that time when HIPEF was combined with antimicrobials. Therefore, combinations of those treatments may be a feasible alternative to thermal pasteurization to ensure the microbiological quality and safety in juices, and to avoid the risk of foodborne illness caused by the consumption of these commodities. No significant changes on the sensory attributes in all studied fruit juices processed by HIPEF were found; but, when citric acid or cinnamon bark oil were added, noticeable changes on some sensory attributes such as aroma, taste and sourness of these fruit juices were perceived.