The switch mechanism of the cell death mode from apoptosis to necrosis in menadione-treated human osteosarcoma cell line 143B cells

Time-dependent changes in the cell death mode from apoptosis to necrosis were studied in cultured 143B cells treated with menadione, an anti-cancerous drug, excluding a possible involvement of "secondary necrosis." The population of apoptotic cells judged by FITC-Annexin V and propidium iodide (PI) double staining reached its maximum at 6 hours after 100 microM menadione treatment followed by an abrupt decrease thereafter, while that of necrotic cells continuously increased reaching 90% at 24 hours. Electron microscopically, cells attached to the culture dish at 6 hours after the treatment consisted of two different types of cells: cells with typical apoptotic features occupying the major population and those with condensed nuclei and swollen cytoplasm. Cells attached to the culture dish at 8 hours after the treatment consisted exclusively of those with condensed nuclei and swollen cytoplasm. Mitochondria in these cells showed various structural changes: those swollen to various degrees with deposition of flocculent densities, or those with highly condensed matrix. Distinct decreases both in intracellular levels of ATP and caspase-3-like activities and remarkable elevations of intracellular levels of superoxide, which were partly suppressed by NAD(P)H oxidase inhibitors, occurred at 6 hours after the treatment. These results may suggest that distinct increases of the intracellular level of superoxide derived from plasma membrane NAD(P)H oxidase besides that from mitochondria have triggered the transition of cell death mode from apoptosis to necrosis. Transition of highly condensed mitochondria to extremely swollen ones may reflect necrotic processes in menadione-treated cells. The present study strongly suggests that time-dependent study is essential using the electron microscopic technique to analyze detailed processes in the changes of the cell death mode.     

Speech nonfluency detection using Kohonen networks

This work covers the problem of application of neural networks to recognition and categorization of non-fluent and fluent utterance records. Fifty-five 4-s speech samples where the blockade on plosives (p, b, t, d, k and g) occurred and 55 recordings of speech of fluent speakers containing the same fragments were applied. Two Kohonen networks were used. The purpose of the first network was to reduce the dimension of the vector describing the input signals. A result of the analysis was the output matrix consisting of the neurons winning in a particular time frame. This matrix was taken as an input for the next self-organizing map network. Various types of Kohonen networks were examined with respect to their ability to classify utterances correctly into two, non-fluent and fluent, groups. Good examination results were accomplished and classification correctness exceeded 76%.     

Simulation of SAR images of urban areas by using the ray tracing method with measured values of backscatter coefficients

This study uses the ray tracing method to simulate synthetic aperture radar (SAR) images of urban areas. The images are constructed for polarisations: horizontal-horizontal (HH) and vertical-vertical (VV), and different types of buildings, vegetation, and streets. Simulated images of a given area are compared with real SAR images of the same area acquired by the TerraSAR-X satellite. The simulations use the measured backscatter coefficient for HH and VV polarisations and for five different classes of terrain: houses, trees, shrubs, grass, and ground. For multiple reflections, we apply the generalized bistatic Lambertian model. The results show that, despite the limits of the ray tracing method and the approximations involved in modelling three-dimensional objects in the simulated scene, the simulated SAR images correspond well with the actual scene. All features present in the real image are reproduced in the simulated image; in particular, the double reflections of buildings and the surrounding ground appear clearly. However, discrepancies exist, and these are also discussed.     

Influence of electron impact ionization on the efficiency of thermoemission ion source

The electron impact ionization by accelerated thermionic electrons is included into the numerical model of thermoemission ion source. Mean free paths of atoms in the ionizer are comparable with the ionizer size at high working temperatures (3500 K). The dependence of the source efficiency on the ionizer temperature and the electron impact ionization cross-section is studied. In the case of substances having a small ionization coefficient (β ? 1) the contribution of the electron impact ionization may be dominant at high temperatures and the predictions based on previous surface ionization model can be changed significantly.     

Diffusion cooling of thermal neutrons in the outer Plexiglas layer of a two-zone system with non-hydrogenous material inside

Diffusion cooling of thermal neutron flux in a finite volume of a medium results from the leakage of neutrons. The cooling effect is particularly complex when the system consists of zones with different neutron scattering properties. A study is presented on the diffusion cooling in Plexiglas (hydrogenous material), which constitutes an outer cylindrical shell surrounding an inner cylinder made of a non-hydrogenous substance. The pulsed neutron method has been used. Numerous series of the desired pulsed neutron experiments in two-zone cylindrical systems have been substituted by Monte Carlo simulations. The decay constant of the fundamental mode in the time distribution of the pulsed thermal neutron flux has been determined in each experiment. The so-called theoretical decay constants (defined under a particular assumption) have been calculated as a function of the system geometry and neutron dynamic parameters including the diffusion cooling coefficient of the outer Plexiglas shell. The variability of this parameter has been determined from a combination of experimental and theoretical results. For a system with a theoretical decay constant varying between 12,000 and 34,000 s⁻¹, the diffusion cooling coefficient of Plexiglas in the outer layer varies between 9000 and 4800 cm⁴ s⁻¹ with the latter being close to the value for homogeneous material. A function has been obtained and successfully applied in interpreting real experiments using Czubek’s method of measuring the absorption cross-section of small samples.     

A Comparative Study of the Quality of Strawberry Purée Preserved by Continuous Microwave Heating and Conventional Thermal Pasteurization During Long-Term Cold Storage

This study was aimed at monitoring changes in the quality of strawberry purée preserved by continuous microwave heating (MV) at 90 and 120 °C for 10 s and conventional thermal pasteurization (CTP) at 90 °C for 15 min during cold storage (6 °C), and determining its shelf-life. The shelf-life of MV and CTP-preserved products established on the basis of microbiological changes was more than 52 weeks (<1 log cfu of yeasts, moulds, and total microbial count per gram). During this time, 43 and 34 % of polyphenols, 89 and 58 % of anthocyanins, as well as 57 and 52 % of antioxidant capacity decrease were noted, for MV and CTP-preserved samples respectively; vitamin C was completely degraded. Color changes were more visible for MV (ΔE?=?10.82) compared with the CTP-preserved sample (ΔE?=?5.14). The kinetic rate of degradation of nutrients was higher for MV- compared to CTP-preserved purée. The recommended cold shelf-life for the MV-preserved purée was estimated at 100 days, during which time it was of a superior quality compared with CTP-preserved purée.     

The transformation of coal fly ash deposited on wet landfills

The stability of the ashes taken from the three heat-power plants showed that each day of storage in wet landfill causes transformation in their physical and chemical composition. At low temperatures, the spherical grains become brittle and consequently undergo cracking. The studies with a laser diffractometer have shown changes in particle size distribution during the experiment. The pozzolanic activity of the studied ashes significantly decreased under the weathering impact.