51 research outputs found
Controlled motion of domain walls in submicron amorphous wires
© 2016 Author(s). Results on the control of the domain wall displacement in cylindrical Fe77.5Si7.5B15 amorphous glass-coated submicron wires prepared by rapid quenching from the melt are reported. The control methods have relied on conical notches with various depths, up to a few tens of nm, made in the glass coating and in the metallic nucleus using a focused ion beam (FIB) system, and on the use of small nucleation coils at one of the sample ends in order to apply magnetic field pulses aimed to enhance the nucleation of reverse domains. The notch-based method is used for the first time in the case of cylindrical ultrathin wires. The results show that the most efficient technique of controlling the domain wall motion in this type of samples is the simultaneous use of notches and nucleation coils. Their effect depends on wire diameter, notch depth, its position on the wire length, and characteristics of the applied pulse
Vegetation-based landscape regions of Hungary.
he first version of the map of the Hungarian vegetation-based landscape regions were prepared
at the scale of 1 : 200,000 (1 km or higher resolution). The primary goal of the map was
to provide an exact background for the presentation and evaluation of the data of theMÉTA
database. Secondly, we intended to give an up-to-date and detailed vegetation-based division
of Hungary with a comprehensive nomenclature of the regions. Regions were primarily defined on the basis of their present zonal vegetation, or their dominant extrazonal or
edaphic vegetation. Where this was not possible, abiotic factors that influence the potential
vegetation, the flora were taken into consideration, thus, political and economical factors
were ignored. All region borders were defined by local expert botanists, mainly based on
their field knowledge. The map differs in many features from the currently used, country-
wide, flora- or geography-based divisions in many features. We consider our map to be
temporary (i.e. a work map), and we plan to refine and improve it after 5 years of testing
Reversible isomerization of an azobenzene derivative adsorbed on Au(111): Analysis using vibrational spectroscopy
High resolution electron energy loss spectroscopy (HREELS) is employed to analyze reversible changes in the geometrical structure of the molecular switch di-methoxy- tetra-tert-butyl-azobenzene (diM-TBA) adsorbed on Au(111), which are induced by UV-light and thermal activation. While for one monolayer (ML) coverage no changes in the vibrational structure due to UV-light exposure at 3.5 eV are observed, illumination of 2 ML of diM-TBA leads to a pronounced modication of the vibrational spectra, which we assign to a trans → cis isomerization. The reverse process, i.e., the cis → trans isomerization, can be stimulated by thermal activation.We propose that the photoisomerization is driven by a direct (intramolecular) electronic excitation of the adsorbed diM-TBA molecules in the second ML analogous to diM-TBA in the liquid phase
Adsorption and switching properties of a N-benzylideneaniline based molecular switch on a Au(111) surface
High resolution electron energy loss spectroscopy is employed to analyze the adsorption geometry and the photoisomerization ability of the molecular switch carboxy-benzylideneaniline (CBA) adsorbed on Au(111). CBA adopts on the Au(111) surface a planar (trans) configuration in the first monolayer (ML) as well as for higher coverages (up to 6 ML), contrary to the geometry in solution, which is strongly non-planar. Illumination with UV light of CBA in direct contact with the Au(111) surface (≤ 1 ML) caused no changes in the vibrational structure, whereas at higher coverages ( > 1 ML) pronounced modifications of vibrational features are observed, which we assign to a trans → cis isomerization. Thermal activation induced the back reaction to trans-CBA. We propose that the photoisomerization is driven by a direct (intramolecular) electronic excitation of the adsorbed CBA molecules in the second ML (and above) analogous to CBA in the liquid phase
Conductance Changes of Na<sup>+</sup> Channels during the Late Na<sup>+</sup> Current Flowing under Action Potential Voltage Clamp Conditions in Canine, Rabbit, and Guinea Pig Ventricular Myocytes
Late sodium current (INa,late) is an important inward current contributing to the plateau phase of the action potential (AP) in the mammalian heart. Although INa,late is considered as a possible target for antiarrhythmic agents, several aspects of this current remained hidden. In this work, the profile of INa,late, together with the respective conductance changes (GNa,late), were studied and compared in rabbit, canine, and guinea pig ventricular myocytes using the action potential voltage clamp (APVC) technique. In canine and rabbit myocytes, the density of INa,late was relatively stable during the plateau and decreased only along terminal repolarization of the AP, while GNa,late decreased monotonically. In contrast, INa,late increased monotonically, while GNa,late remained largely unchanged during the AP in guinea pig. The estimated slow inactivation of Na+ channels was much slower in guinea pig than in canine or rabbit myocytes. The characteristics of canine INa,late and GNa,late were not altered by using command APs recorded from rabbit or guinea pig myocytes, indicating that the different shapes of the current profiles are related to genuine interspecies differences in the gating of INa,late. Both INa,late and GNa,late decreased in canine myocytes when the intracellular Ca2+ concentration was reduced either by the extracellular application of 1 µM nisoldipine or by the intracellular application of BAPTA. Finally, a comparison of the INa,late and GNa,late profiles induced by the toxin of Anemonia sulcata (ATX-II) in canine and guinea pig myocytes revealed profound differences between the two species: in dog, the ATX-II induced INa,late and GNa,late showed kinetics similar to those observed with the native current, while in guinea pig, the ATX-II induced GNa,late increased during the AP. Our results show that there are notable interspecies differences in the gating kinetics of INa,late that cannot be explained by differences in AP morphology. These differences must be considered when interpreting the INa,late results obtained in guinea pig
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