Aging of the over-voltage protection elements caused by over-voltages

The aim of this work is examining the influence of the number of the activation––over-voltage pulses to the aging of over-voltage protection elements. Both non-linear (gas-filled surge arresters (GFSA), varistors, over-voltage diodes) and linear (capacitors––constituents of filters) over-voltage protection elements were tested. The instruments employed allow reliable measurements, 1000 consecutive activation were tested. The double-exponential current pulse (amplitude I₁^max=13 A, I₂^max=16 A, rise time T₁=8 μs, fall time T₂=20 μs) for non-linear elements and a double-exponential over-voltage pulse (rise time T₁=1.2 μs, fall time T₂=50 μs) of the amplitude U₁^max=320 V, U₂^max=480 V and U₃^max=640 V for capacitors were used. The experimental results show that the over-voltage diodes are the most reliable elements in view of characteristic modifications that are consequence of aging. However, it was observed that varistors, GFSA and capacitors undergo noticeable changes in characteristics.     

Preliminary comparison of behavioral and biochemical effects of chronic transcranial magnetic stimulation and electroconvulsive shock in the rat

To confirm the assumption that repetitive rapid-rate transcranial magnetic stimulation (TMS) induces the functional and structural changes analogous to those which are evoked during electroconvulsive shock (ECS), we compared now the effects of treatments with TMS and ECS on the behavioral responses in rats. We also tested the reactivity of the cyclic adenosine monophosphate (AMP) generating system in cerebral cortical slices. TMS similarly to ECS shortened the immobility time in the forced swimming test and produced a depression of responsiveness of the noradrenaline-stimulated cyclic AMP generating system, although the significance of the latter effect was borderline. In contrast to ECT, TMS produced no such immediate behavioral effects as analgesia and depression of the early phase of locomotor activity. The data suggest that TMS produces in rats some responses that are regarded as predictive for antidepressant activity, similar to those produced by ECS, but less adverse effects.     

The influence of radon measurement errors on the uncertainties of epidemiological case-control studies

To analyse the influence of the parameters of case and control groups and uncertainties of radon concentration assessments on the dose-effect dependence, a special computer program was designed. The influence of measurement errors on the uncertainties of radon case-control analysis is demonstrated on examples of hypothetical case and control groups with sizes from 250-500 to 7000-14,000 members. The modelling was conducted using a Monte Carlo technique for different values of measurement uncertainties. The random errors of radon assessment affect both the numerical value of the slope coefficient β of the linear dependence of relative risk of lung cancer incidence on indoor radon concentration and the accuracy of this value. The extrapolation of the dependence of the slope coefficient β on the total (initial plus additional) random error of radon concentration assessment is suggested for the assessment of an unbiased value of the slope coefficient β.     

Lipidation of Temporin-1CEb Derivatives as a Tool for Activity Improvement,Pros and Cons of the Approach

The alarming raise of multi-drug resistance among human microbial pathogens makes the development of novel therapeutics a priority task. In contrast to conventional antibiotics, antimicrobial peptides (AMPs), besides evoking a broad spectrum of activity against microorganisms, could offer additional benefits, such as the ability to neutralize toxins, modulate inflammatory response, eradicate bacterial and fungal biofilms or prevent their development. The latter properties are of special interest, as most antibiotics available on the market have limited ability to diffuse through rigid structures of biofilms. Lipidation of AMPs is considered as an effective approach for enhancement of their antimicrobial potential and in vivo stability; however, it could also have undesired impact on selectivity, solubility or the aggregation state of the modified peptides. In the present work, we describe the results of structural modifications of compounds designed based on cationic antimicrobial peptides DK5 and CAR-PEG-DK5, derivatized at their N-terminal part with fatty acids with different lengths of carbon chain. The proposed modifications substantially improved antimicrobial properties of the final compounds and their effectiveness in inhibition of biofilm development as well as eradication of pre-formed 24 h old biofilms of Candida albicans and Staphylococcus aureus. The most active compounds (C5-DK5, C12-DK5 and C12-CAR-PEG-DK5) were also potent against multi-drug resistant Staphylococcus aureus USA300 strain and clinical isolates of Pseudomonas aeruginosa. Both experimental and in silico methods revealed strong correlation between the length of fatty acid attached to the peptides and their final membranolytic properties, tendency to self-assemble and cytotoxicity.     

IT-Sicherheitsprüfungen durch die Interne Revision

Mit steigender Durchdringung der Kreditinstitute mit der IT und immer st?rker werdender Abh?ngigkeit des Bankgesch?fts von dem Netz steigen auch die mit der Verletzbarkeit und Ausfall der IT-Systeme verbundenen Risiken. Für die IT-Revision bedeutet dies ein wachsendes Engagement im Rahmen von Sicherheitsprüfungen und- Beratungen, um diesen Risiken in angemessener Weise zu begegnen. Durch Einsatz geeigneter Prüfungsmethodik und hoher fachlichen Qualifikationen der Revisoren k?nnen die Sicherheitsprüfungen zu einer wichtigen Erfolgsdeterminante eines Instituts werden.     

Direct and indirect effects of perceived price on perceived value of mobile phones

Nowadays many leading companies understand that creating outstanding customer value is necessary to achieving sustainable market success. The main problem discussed in this article is the examination of factors affecting perceived value, emphasizing the relationship between perceived price and perceived value. Based on literature and their own findings, the authors designed a model of relationships between researched factors. This model was tested using structural equation modeling. The results reflected that statistically significant relationships exists and that perceived price has direct as well as indirect efects on perceived product value.     

GISAXS study of temperature evolution in nanostructured CeVO4 films

Cerium vanadate films on glass substrate were obtained by sol–gel process. The morphology of these nanostructured and porous films was studied by grazing-incidence small-angle X-ray scattering (GISAXS) at synchrotron ELETTRA, Trieste, Italy. The aim of the GISAXS study was to investigate the changes in grain sizes due to the temperature evolution with three different time intervals (5, 15 and 30 min) of annealing at 673 K. We found that the effects of the different times of annealing are different for surface and bulk properties of this V/Ce oxide.     

Mechanistic Consequences of the “Binary Solutions” Model

The mechanistic consequences of a new TL-chromatographic model are elucidated and the relevant conclusions are drawn as to the possible intermolecular interactions between the chromatographed substance and the remaining system components.     

Extraction of copper from acid sulphate solutions by 2-hydroxy-5-n-nonyl and 2-hydroxy-4′-n-nonylbenzophenone oximes

The study of copper extraction shows that the position of the chain (5 or 4′) does not influence the statics of copper extraction from ammonia solutions by alkyl derivatives of 2-hydroxybenzophenone oxime. Acid solutions of 2-hydroxy-4′-n-nonylbenzo-phenone oxime can extract more copper than 2-hydroxy-5-n-nonylbenzophenone oxime, but less than 2-hydroxy-5-n-alkylbenzaldehyde oxime.     

Preparation of membrane-immobilised enzymes for phenol decomposition

A method for the preparation of membranes with immobilised enzymes for the biological degradation of phenols is described. In the first stage, an enzymatic fraction from bacterial strains has been isolated. The enzyme membranes were obtained by ultrafiltration of protein solution through a membrane support made of non-cellulose polymers. All enzymes were adsorbed onto the membrane surface. The enzyme membranes were found to degrade 70–80% of the phenol during single dead-end ultrafiltration at a pressure of 1 × 10⁵?3 × 10⁵ Pa. The retention coeffcient of the ultrafiltration process also amounted to 70–80%.