Amplified oligonucleotide sensing in microliter volumes containing copper ions by solution streaming

We present a simple, cost-effective design for amplifying oligodeoxynucleotide (ODN) sensing, in microliter ODN volumes containing copper ions, by solution streaming (bubbling). The inert gas streaming (bubbling) at a constant pressure of 0.04 bar drives the motion of a 30-microL ODN droplet containing a three-electrode circuit (inverted drop microcell), and in the presence of copper ions offers an approximately 50-times improvement in the detection of ODN samples. The detection of ODNs at the carbon paste electrode is based on the enhancement of the oxidation peaks of purine bases (adenine and guanine) by the anodic stripping of the electrochemically accumulated complex of Cu(I) with purine base residues of acid hydrolyzed ODN samples (Cu(I)-ahODN complex). We used the proposed method for (i) the determination of the percentage content of adenine and guanine units within analyzed ODN samples at subnanomolar concentrations (related to monomer content) and (ii) the detection of the (TTC)n triplet expansion using magnetic DNA hybridization with reporter probes containing guanine units (the TTC trinucleotide repeat expansion is associated with serious hereditary diseases, including Friedreich ataxia).     

The Possibilities of Particle Analysis Demonstrated by the Measurement of the Colloidal Stability of Filtered Beer

Long‐term stability is one of the most important quality criteria of beer. Three groups of measuring methods are available for its determination: real time tests, predictive tests and indicative tests. One of the most common methods is the predictive forcing test, which is a time‐consuming method for accelerating beer ageing, e.g., at 0°C and 60°C. Two ways exist to perform this test: (1) follow‐up of haze development and determination of the lag phase or (2) the measurement of haze values after several days. The first option was evaluated by performing a long‐term Forcing test over a period of 4 months by analyzing a bottom‐fermented beer. It was shown that the haze curve followed a typical course with a lag phase, an increase phase and a stationary phase. Significant differences between the measurement after the cooling and the warm period were shown. In search of quicker methods and more accurate predictive indicators, the charge titration method was developed as an alternative to determine the particle charge of filtered beers, whereupon the relationship was elucidated between the increase in hazing and decrease of potential along with the advanced aging of beer. The results showed that with increased particle size due to agglomeration, the total charge decreased. In this array of trials, two differently stabilized beers were examined. Although both beers showed different haze values in the beginning (0.32 EBC and 1.30 EBC), the less stabilized beer had only 10 warm days and in contrast the beer with the good stabilization had over 20 warm days. With the help of the total charge, predictions were possible regarding the long‐term stability of the beer.     

The effect of the combination of reducing and oxidising agents on the viscoelastic properties of dough and sensory characteristics of buns

BACKGROUND: The effects of mixtures of reducing and oxidising agents on the rheological characteristics and quality of wheat flour dough and the sensory characteristics of buns were studied. RESULTS: In chemical analyses, no differences between control dough and doughs with individual mixtures of additives were found. Rheological measurements showed that increasing addition of L ‐ascorbic acid + L ‐tryptophan mixture to the dough increased its tenacity and decreased its extensibility. Increasing addition of L ‐ascorbic acid + L ‐threonine mixture also led to an increase in dough tenacity but to a slight increase in dough extensibility. Increasing addition of L ‐ascorbic acid + inactivated dry yeast mixture to the dough resulted in a decrease in tenacity and an increase in extensibility. Two other additive mixtures, L ‐ascorbic acid + L ‐cysteine hydrochloride monohydrate and L ‐cysteine p.a. + inactivated dry yeast, reduced both the tenacity and extensibility of the dough. In sensory analyses, differences in dryness, pliability, sensation when swallowing, quality and texture of buns with additive mixtures were found in comparison with control buns, but gumminess did not change significantly with increasing amount of additive mixtures. CONCLUSION: The additive mixtures tested had a positive influence on bakery products. Copyright © 2010 Society of Chemical Industry     

Texture evolution in Fe–3% Si steel treated under unconventional annealing conditions

The present work investigates texture evolution stages in grain-oriented steel heat-treated using unconventional conditions. The Fe–3%Si steel taken after final cold rolling reduction from an industrial line was subjected to a laboratory isothermal annealing at different temperatures. The annealing temperatures were varied in a range of 850–1150 °C. During the annealing each specimen was heated at 10 °C/s and kept at the stated temperature for 5 min. Development of microstructure and texture in the annealed specimens were followed by the DC measurements of magnetic properties. The grain oriented steel, taken from the same industrial line after final box annealing was also analyzed and compared with the laboratory annealed specimens. It was shown that there is an optimal temperature region that, with combination of a fast heating rate, led to the best conditions of a drastically reduced development time of the {110} < 001 > crystallographic texture in the cold rolled grain-oriented steel. Materials heat treated below the optimum temperature region account for a primary recrystallization, while applying heat above this region leads to a secondary recrystallization without abnormal grain growth. Moreover, in the optimum temperature range, there was a particular temperature leading to the most optimal microstructure and texture. The magnetic properties, measured after the optimal heat treatment, were close to that measured on specimens taken after the final box annealing. The electron back scattered diffraction measurement technique revealed that sharpness of the {110} < 001 > crystallographic texture, developed at the optimum temperature is comparable to the steel taken after the industrial final box annealing. This fact is evidence that there is a temperature where the abnormal grain growth proceeds optimally.     

Surface properties of poly(ethylene terephthalate) foils of different thicknesses

Surface properties of commercially available poly(ethylene terephthalate) (PET) foils of different thicknesses (3, 13, 23, 50, and 100 μm) were characterized using different analytical methods. Surface roughness and morphology were determined by atomic force microscopy, goniometry was used for determination of contact angle (wettability of surface) and electrokinetical analysis (zeta potential) for characterization of surface polarity and conductivity. X-ray photoelectron spectroscopy was used for characterization of PET surface chemistry. Infrared spectroscopy and differential scanning calorimetry (DSC) were used for determination of crystallinity portion. By DSC analysis, it was confirmed that the crystallinity portion depends on the foil thickness. Most important result of this study is that the surface properties of PET foils depend not only on the foil thickness but also on the foil side under study. This finding may be of importance for future experiments performed on PET foils and for their application in tissue engineering or microelectronics.     

Fluorescent labelled thiourea-bridged glycodendrons

GlcNAc-coated glycodendrimers, which are polyvalent glycomimetics, display strong in vitro affinity for the rat natural killer cell protein-1A (NKR-P1A), a C-type lectin-like receptor of natural killer (NK) cells in rats, humans and some strains of mice. Administration of these compounds in vivo results in a substantial increase in the antitumour activity with involvement of the natural cell immunity. To clarify the in vitro and in vivo fate of these molecules, we synthesized labelled glycodendron analogues of the previously studied glycodendrimers. Labelling with fluorescent tags enabled the localization of the glycodendrons in white blood cells, tumours and other tissues by using different imaging techniques such as fluorescence and confocal microscopy. These studies are useful for probing the mechanism of action and fate of artificial ligands and the cell receptors involved.     

Particle swarm optimization for problems with variable number of dimensions

Some real-life optimization problems, apart from dependence on the combination of state variables, also show dependence on the complexity of the model describing the problem. Changing model complexity implies changing the number of decision space dimensions.

A new method called Particle Swarm Optimization for Variable Number of Dimensions is developed here. The well-known particle swarm optimization procedure is modified to handle spaces with a variable number of dimensions within a single run. Some well-known benchmark problems are modified to depend on the number of dimensions. Novel performance metrics are defined in the article to evaluate convergence properties of the method. Some recommendations for setting the optimization are made according to results of the method on the proposed benchmark test suite. The method is compared with conventional swarm strategies able to solve problems with variable number of dimensions.     

Neuron Adhesion on Diamond: Competition between Polymer Treatment and Surface Morphology

The ability to form an efficient interface between material and neural cells is a crucial aspect for construction of neuroelectrodes. Diamond offers material characteristics that could, to a large extent, improve the performance of neuroelectrodes. The greatest advantage of diamond is a large variety of material and surface properties such as electrical conductivity, surface morphology, and surface chemistry. Such a variety of material characteristics can lead to various cellular responses. Here, the authors compare survival, adhesion, and neurite formation of primary neurons on diamond thin films of various morphologies and treatments with several types of polymers commonly used to enhance cell adhesion. The authors find that the variation of surface roughness of nanocrystalline diamond film when coated with polymer does not have a major influence on neuron survival or adhesion. The adhesion of neurons can be influenced by the selected type of polymer coating. High molecular weight of polyethylenimine results in lower viability, adhesion, and neurite formation. The addition of laminin to treated films do not lead to significant improvements in neuron adhesion and neurite development. Their findings emphasize the importance of the correct polymer treatment over morphological properties of diamond thin films as a material for forming interfaces with primary neurons.

     

High effective silica fume alkali activator

Growing demands on the engineering properties of cement based materials and the urgency to decrease unsuitable ecologic impact of Portland cement manufacturing represent significant motivation for the development of new cement corresponding to these aspects. One category represents prospective alkali activated cements. A significant factor influencing their properties is alkali activator used. In this paper we present a new high effective alkali activator prepared from silica fume and its effectiveness. According to the results obtained this activator seems to be more effective than currently used activators like natrium hydroxide, natrium carbonate, and water glass.