Preparation and physicochemical characteristics of cryogel based on gelatin and oxidised dextran

In this study, a novel method of preparation of cryogels based on oxidised dextran (Ox.D) and gelatin (Gel) without sodium borohydride is proposed. The physico-chemical properties of obtained hydrogels were investigated. It was found that the stability of cryogels Ox.D–Gel is significantly depended on pH, and mechanical properties were improved after the freeze drying. The schemes of the reactions between Ox.D and Gel at different steps of the treatment of the material were suggested. According to ¹H-NMR data, the Amadori rearrangement occurred under the step of cryogelation. The increase of cross-linking degree through the formation of additional Schiff’s base group was observed as a result of incubation at high humidities or elevated temperature (60 °C). The obtained cryogels can be used as biocompatible and biodegradable scaffolds for proliferation of cells or other biomedical applications.     

The role of non-exact replications in software engineering experiments

In no science or engineering discipline does it make sense to speak of isolated experiments. The results of a single experiment cannot be viewed as representative of the underlying reality. Experiment replication is the repetition of an experiment to double-check its results. Multiple replications of an experiment increase the confidence in its results. Software engineering has tried its hand at the identical (exact) replication of experiments in the way of the natural sciences (physics, chemistry, etc.). After numerous attempts over the years, apart from experiments replicated by the same researchers at the same site, no exact replications have yet been achieved. One key reason for this is the complexity of the software development setting, which prevents the many experimental conditions from being identically reproduced. This paper reports research into whether non-exact replications can be of any use. We propose a process aimed at researchers running non-exact replications. Researchers enacting this process will be able to identify new variables that are possibly having an effect on experiment results. The process consists of four phases: replication definition and planning, replication operation and analysis, replication interpretation, and analysis of the replication’s contribution. To test the effectiveness of the proposed process, we have conducted a multiple-case study, revealing the variables learned from two different replications of an experiment.     

Direct Determination of Saccharin and Acesulfame-K in Sweeteners and Fruit Juices Powders

A simple and rapid analytical procedure for determination of saccharin (SAC) and acesulfame-K (AC-K) based on UV-vis measurements and partial least squares (PLS) was proposed. Thus, an experimental design at levels 2 and 15 mg l⁻¹ for SAC and 2 and 20 mg l⁻¹ for AC-K was applied. Because real samples usually contain SAC and AC-K combined with aspartame (ASP), this interference was also included in the model. The procedure was successfully applied for SAC and AC-K simultaneous determination in sweeteners and fruit juice powders, without any separation step to remove ASP. The results were validated by using spiked samples, and the obtained recoveries were satisfactory.     

Evaluation of Stable LifeAct-mRuby2- and LAMP1-NeonGreen Expressing A549 Cell Lines for Investigation of Aspergillus fumigatus Interaction with Pulmonary Cells

Inhaled Aspergillus fumigatus spores can be internalized by alveolar type II cells. Cell lines stably expressing fluorescently labeled components of endocytic pathway enable investigations of intracellular organization during conidia internalization and measurement of the process kinetics. The goal of this report was to evaluate the methodological appliance of cell lines for studying fungal conidia internalization. We have generated A549 cell lines stably expressing fluorescently labeled actin (LifeAct-mRuby2) and late endosomal protein (LAMP1-NeonGreen) following an evaluation of cell-pathogen interactions in live and fixed cells. Our data show that the LAMP1-NeonGreen cell line can be used to visualize conidia co-localization with LAMP1 in live and fixed cells. However, caution is necessary when using LifeAct-mRuby2-cell lines as it may affect the conidia internalization dynamics.     

Estimating Basic Characteristics of Arrival Processes in Telecommunication Networks by Empirical Data

Considering the realistic teletraffic analysis in advanced telecommunication networks, the estimation of basic characteristics of arrival processes by empirical data is an important subject of current research. Using independent observations of the interarrival times between events and the mean numbers of events in intervals of fixed length, we propose methods to estimate the intensity of a nonhomogeneous arrival stream, particularly a Poisson process, and the renewal function of a renewal process. We formulate the estimation task as stochastically ill-posed problem and apply procedures for the stabilization of the estimates.     

Light-induced heat and mass transfer of gas in a plane channel

The paper deals with the processes of heat and mass transfer of a rarefied gas in a plane channel in the field of resonance radiation. The problem is solved using linearized kinetic equations with a first-order model integral of collisions. The surface and collision mechanisms of light-induced drift are investigated, as well as the mechanism of heat flux at arbitrary values of the Knudsen number. Analytical expressions for channel cross section-averaged flows are obtained at high and low values of the Knudsen number.Translated from Teplofizika Vysokikh Temperatur, Vol. 43, No. 1, 2005, pp. 127–135. Original Russian Text Copyright © 2005 by I. V. Chermyaninov, V. G. Chernyak, and E. P. Khinkina.     

Artificial gravity loading increases the effects of the glutamate transporter inhibitors on the glutamate release and uptake in rat brain nerve terminals

The present study evaluated the effect of artificial gravity loading on transporter-mediated uptake and release of L-glutamate using the inhibitors of glutamate transporters as tools. The competitive nontransportable, DL-threo-beta-benzyloxyaspartate (DL-TBOA), and transportable, DL-threo-beta-hydroxyaspartate (DL-THA), inhibitors were demonstrated to better inhibit the L-[¹⁴C]glutamate uptake under centrifuge-induced hypergravity compared with the normal gravity control. The effect of DL-TBOA on depolarization-induced carrier-mediated L-[¹⁴C]glutamate release also increased after hypergravity loading in Na⁺- and low [Na⁺] NMDG- supplemented media. 10 µM DL-TBOA-induced decrease in L-[¹⁴C]glutamate release in Na⁺ — supplemented medium was 15.2±2.2 % in the control experiments and 26.2±3.9 % after centrifuge-induced loading (P≤0,05) and in low [Na⁺] medium was 37.0±2.5 % and 45.0±3.4 %, respectively.     

Base Flip in DNA Studied by Molecular Dynamics Simulations of Differently-Oxidized Forms of Methyl-Cytosine

Distortions in the DNA sequence, such as damage or mispairs, are specifically recognized and processed by DNA repair enzymes. Many repair proteins and, in particular, glycosylases flip the target base out of the DNA helix into the enzyme’s active site. Our molecular dynamics simulations of DNA with intact and damaged (oxidized) methyl-cytosine show that the probability of being flipped is similar for damaged and intact methyl-cytosine. However, the accessibility of the different 5-methyl groups allows direct discrimination of the oxidized forms. Hydrogen-bonded patterns that vary between methyl-cytosine forms carrying a carbonyl oxygen atom are likely to be detected by the repair enzymes and may thus help target site recognition.