Three-phase metal kinetics in terrestrial invertebrates exposed to high metal concentrations

Models of metal toxicokinetics are critically evaluated using both newly generated data in the NoMiracle project as well as those originating from older studies. The analysis showed that the most frequently used one-compartment two-phase toxicokinetic model, with one assimilation and one elimination rate constant, does not describe correctly certain data sets pertaining particularly to the pattern of assimilation of trace elements. Using nickel toxicokinetics in carabid beetles and earthworms as examples, we showed that Ni in fact exhibits a three-phase kinetics with a short phase of fast metal accumulation immediately after exposure, followed by partial elimination to an equilibrium concentration at a later stage of a metal exposure phase, and by final elimination upon transfer to an uncontaminated food/soil. A similar phenomenon was also found for data on cadmium kinetics in ground beetles and copper kinetics in earthworms in data already published in the literature that was not accounted for in the earlier analysis of the data. The three-phase model suggests that the physiology of controlling body metal concentrations can change shortly after exposure, at least in some cases, by increasing the elimination rate and/or decreasing metal assimilation. Hence, the three-phase model, that allows for different assimilation and/or elimination rates in different phases of exposure to a toxicant, may provide insight into temporal changes in the physiology of metal handling. Consequently, this alternative model should always be tested when describing metal toxicokinetics when temporal patterns of internal metal concentration exhibit an initial “overshoot” in body metal concentrations.     

The effect of selected functional additives and heat treatment on nitrosamine content in pasteurized pork ham

The influence of pasteurization and sodium chloride, sodium ascorbate, polyphosphates and sodium nitrite coupled with pasteurization on nitrosamine contents in pork was studied. Nitrosamines: dimethylonitrosamine (DMNA) and diethylonitrosamine (DENA) were extracted from raw material, distilled, condensed in an evaporator under lowered pressure and analyzed chromatographically. An inhibitory effect of NaCl and sodium ascorbate on volatile nitrosamines (DMNA and DENA) was seen. Adding solutions of polyphosphates to the meat caused a slight increase in nitrosamine contents, higher than noted with sodium chloride. The effect of these compounds on nitrosamine formation depended on the presence of polyphosphates and sodium nitrite in the brine. If the brine contained nitrites, the adverse effect of sodium ascorbate and NaCl on nitrosamine formation was weaker. Moreover, a strong inhibitory effect of pasteurization on DMNA and DENA formation was observed.     

Neural network adaptation process effectiveness dependent of constant training data availability

The paper discusses and compares two different ways of adapting artificial intelligence systems. One is founded on a well known biological mechanism of gradual training of neurons or other parameters. The second one uses a significant extra feature of training data that ably makes us possible to adapt the artificial intelligence system in more effective way than nature does in biological systems. This extra feature is availability of all training data before the adaptation process begins till an end of which all these data have to be constant. This feature provides an ability to analyze training data globally and very quickly tune an artificial intelligence system with them. The paper focus the attention on this important difference between biological and artificial intelligence problems because in most cases of artificial intelligence problems training data are gathered, available and constant during the training process. On the other hand, the biological nervous systems gather training data during the whole life, have to change the inner model, so training is a very good solution for them because it makes them possible to tune with changing training data. Artificial intelligence systems can also use training inherent in biological systems but in most cases it is possible to find more quickly and effectively the solution if only the mentioned feature is met. The above thesis is illustrated by means of some examples.     

Recognising Algebraic Surfaces from Two Outlines

Photographic outlines of 3 dimensional solids are robust and rich in information useful for surface reconstruction. This paper studies algebraic surfaces viewed from 2 cameras with known intrinsic and extrinsic parameters. It has been known for some time that for a degree d=2 (quadric) algebraic surface there is a 1-parameter family of surfaces that reproduce the outlines. When the algebraic surface has degree d>2, we prove a new result: that with known camera geometry it is possible to completely reconstruct an algebraic surface from 2 outlines i.e. the coefficients of its defining polynomial can be determined in a known coordinate frame. The proof exploits the existence of frontier points, which are calculable from the outlines. Examples and experiments are presented to demonstrate the theory and possible applications.

Aesculus hippocastanum L. as a Stabilizer in Hemp Seed Oil Nanoemulsions for Potential Biomedical and Food Applications

Nanoemulsion systems receive a significant amount of interest nowadays due to their promising potential in biomedicine and food technology. Using a two-step process, we produced a series of nanoemulsion systems with different concentrations of hemp seed oil (HSO) stabilized with Aesculus hippocastanum L. extract (AHE). Water and commercially-available low-concentrated hyaluronic acid (HA) were used as the liquid phase. Stability tests, including an emulsifying index (EI), and droplet size distribution tests performed by dynamic light scattering (DLS) proved the beneficial impact of AHE on the emulsion’s stability. After 7 days of storage, the EI for the water-based system was found to be around 100%, unlike the HA systems. The highest stability was achieved by an emulsion containing 5% HSO and 2 g/L AHE in water, as well as the HA solution. In order to obtain the detailed characteristics of the emulsions, UV-Vis and FTIR spectra were recorded, and the viscosity of the samples was determined. Finally, a visible microscopic analysis was used for the homogeneity evaluation of the samples, and was compared with the DLS results of the water system emulsion, which showed a desirable stability. The presented results demonstrate the possible use of oil emulsions based on a plant extract rich in saponins, such as AHE. Furthermore, it was found that the anti-inflammatory properties of AHE provide opportunities for the development of new emulsion formulations with health benefits.     

Participation of Amyloid and Tau Protein in Post-Ischemic Neurodegeneration of the Hippocampus of a Nature Identical to Alzheimer’s Disease

Recent evidence suggests that amyloid and tau protein are of vital importance in post-ischemic death of CA1 pyramidal neurons of the hippocampus. In this review, we summarize protein alterations associated with Alzheimer’s disease and their gene expression (amyloid protein precursor and tau protein) after cerebral ischemia, as well as their roles in post-ischemic hippocampus neurodegeneration. In recent years, multiple studies aimed to elucidate the post-ischemic processes in the development of hippocampus neurodegeneration. Their findings have revealed the dysregulation of genes for amyloid protein precursor, β-secretase, presenilin 1 and 2, tau protein, autophagy, mitophagy, and apoptosis identical in nature to Alzheimer’s disease. Herein, we present the latest data showing that amyloid and tau protein associated with Alzheimer’s disease and their genes play a key role in post-ischemic neurodegeneration of the hippocampus with subsequent development of dementia. Therefore, understanding the underlying process for the development of post-ischemic CA1 area neurodegeneration in the hippocampus in conjunction with Alzheimer’s disease-related proteins and genes will provide the most important therapeutic development goals to date.     

Transient non‐linear heat conduction–radiation problems—a boundary element formulation

A novel boundary‐only formulation for transient temperature fields in bodies of non‐linear material properties and arbitrary non‐linear boundary conditions has been developed. The option for self‐irradiating boundaries has been included in the formulation. Heat conduction equation has been partially linearized by Kirchhoff's transformation. The result has been discretized by the dual reciprocity boundary element method. The integral equation of heat radiation has been discretized by the standard boundary element method. The coupling of the resulting two sets of equations has been accomplished by static condensation of the radiative heat fluxes arising in both sets. The final set of ordinary differential equations has been solved using the Runge–Kutta solver with automatic time step adjustment. The algorithm proved to be robust and stable. Numerical examples are included. Copyright © 1999 John Wiley & Sons, Ltd.     

Shock wave induced separation control by streamwise vortices

Introduction Normal shock wave – boundary layer interaction (SWBLI) is still an important problem in compressible aerodynamics and still finds a lot of attention. Many methods of such interaction control have been investigated in recent decades[1]. These concerned a local wall modification in a form of a bump and many applications of the transpiration flow through walls. Passive control, active control and mixed hybrid type of flow control by suction and blowing have been extensively studi…     

The effect of microstructure on the mechanical properties of two-phase titanium alloys

This article presents the results of investigations of microstructure and mechanical properties of two-phase +β titanium alloys with different volume fraction of the β-phase. Microstructure of the specimens was examined using an optical microscope. Fracture surfaces were observed by SEM technique. The influence of the microstructure and phase composition on the mechanical properties of the alloys was studied. Static tensile tests, hardness tests and fatigue investigations were performed. It was noticed that the volume fraction and chemical composition of the β-phase has a significant effect on mechanical properties and cracking process during fatigue.