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Book reviews

     

Contact Pattern Analysis: Simulation of a Laser-Assisted Thermographic Approach

The contact pattern, defined as the area where gear teeth come into contact during their meshing, is a crucial quality feature of gears. If the size and location of the contact pattern are wrong, the gear meshing properties can be significantly affected (e.g., lifetime, noise). Despite several disadvantages, the so-called “paste method” is established as a method to analyse contact patterns. Here, a new measuring approach is examined using the Finite Elements Method (FEM). It is based on the heating-up of one tooth flank with a powerful laser, a subsequent partial transfer of the heat to a meshing tooth of the second gear wheel and finally capturing the heat distribution on that flank as an infrared image shortly afterwards. The thermal image should correspond to the contact pattern of that individual combination of teeth. A numerical analysis shows that at medium- and large-sized gears the achievable temperature increase will be high enough to be detected with modern infrared cameras.     

Iron enhances generation of fibrin fibers in human blood: Implications for pathogenesis of stroke

Stroke is associated with the intracerebral formation of fibrin clots which may lead to irreversible brain damage. Thrombolytic therapies employ a variety of natural and/or recombinant plasminogen activators to initiate fibrinolytic degradation of cerebral thrombi. However, such therapies when installed beyond 4‐ to 6‐h window, may fail to achieve the expected outcome. This is due to the hydroxyl radical‐induced modification of fibrin(ogen) molecules rendering them refractory to fibrinolytic degradation, but no cause of the increased free radical generation in stroke was offered. Here, we show by means of electron microscopy that iron ions added to human blood dramatically enhances fibrin fibers formation with thrombin, and significantly delays fibrinolysis during spontaneous clotting of native blood. Iron ions caused the appearance dense matted fibrin deposits, similar, if not identical, to those observed in plasma of patients with stroke. These results may explain a known relationship between thrombotic diseases and the increased body concentrations of free iron and/or hemoglobin derivatives. We conclude that any action resulting in the inhibition of hemostatic abnormalities, as well as in the reduction of body free iron and scavenging of hydroxyl radicals (e.g., by polyphenols) can potentially prevent pathological reactions associated with consequences of stroke. Microsc. Res. Tech. 75:1185–1190, 2012. © 2012 Wiley Periodicals, Inc.     

Ein Beitrag zur Berechnung der Stromverdrängung in einem Bandleiter

Übersicht In der vorliegenden Arbeit wird die Stromverteilung in einem Bandleiter mit Hilfe der Fredholmschen Integralgleichung analysiert. Es wird der Vergleich zwischen den numerisch ausgewerteten und den in der Literatur mit Hilfe von anderen Verfahren berechneten Ergebnisse durchgeführt.

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A contribution to the calculation of eddy-current distribution in a strip line

Contents In the paper eddy-current distribution in a strip line is analysed by means of the Fredholm integral equation method. The results obtained are compared with the results achieved elsewhere by means of the other methods.

     

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Über die Abschirmung stationärer und nichtstationärer Magnetfelder von Zylinderspulen

Übersicht Die Verteilung des magnetischen Feldes der über einer leitenden permeablen Platte angeordneten Zylinderspule endlicher Abmessungen. Abschirmende Wirkung der Platte im stationären Zustand bei zeitlich sinusförmiger Erregung. Die Zeitkonstante der Ausgleichvorgänge.

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Contents Electromagnetic field distribution due to a cylindrical coil placed over a conductive ferromagnetic plate. Relations for the screening electromagnetic field outside the plate in steady-state. Time constant of transient eddy currents.

     

The role of dorsal hippocampus and basolateral amygdala NMDA receptors in the acquisition and retrieval of context and contextual fear memories.

The authors used 3-phase context preexposure facilitation methodology to study the contribution of N-methyl-D-aspartate (NMDA) receptors in dorsal hippocampus (DH) and the basal lateral region of the amygdala (BLA) to (a) acquisition of the context memory, (b) retrieval of the context memory, (c) acquisition of context-shock association, and (d) retrieval of the context-shock association. The NMDA receptor antagonist D-2-amino-5 phosphonopentanoic acid (D-AP5) was injected into either the DH or BLA prior to (a) the context preexposure phase, (b) the immediate shock phase, or (c) the test for contextual fear. Antagonizing NMDA receptors in the DH impaired the acquisition of the context memory but did not affect its retrieval or retrieval of the fear memory. Antagonizing NMDA receptors with D-AP5 in the BLA impaired acquisition of the context-shock association but had no effect on the expression of fear. However, both DL-AP5 and L-AP5 reduced the expression of fear when they were injected into the amygdala prior to testing for contextual fear. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Book reviews

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Book reviews

     

Book reviews

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