Instability of quasi-static potential oscillations of a thin conductor, around which a plasma flows

1979 ◽  
Vol 22 (7) ◽  
pp. 541-546 ◽  
Author(s):  
V. Ya. �idman
Author(s):  
H. Kohl

High-Resolution Electron Microscopy is able to determine structures of crystals and interfaces with a spatial resolution of somewhat less than 2 Å. As the image is strongly dependent on instrumental parameters, notably the defocus and the spherical aberration, the interpretation of micrographs necessitates a comparison with calculated images. Whereas one has often been content with a qualitative comparison of theory with experiment in the past, one is currently striving for quantitative procedures to extract information from the images [1,2]. For the calculations one starts by assuming a static potential, thus neglecting inelastic scattering processes.We shall confine the discussion to periodic specimens. All electrons, which have only been elastically scattered, are confined to very few directions, the Bragg spots. In-elastically scattered electrons, however, can be found in any direction. Therefore the influence of inelastic processes on the elastically (= Bragg) scattered electrons can be described as an attenuation [3]. For the calculation of high-resolution images this procedure would be correct only if we had an imaging energy filter capable of removing all phonon-scattered electrons. This is not realizable in practice. We are therefore forced to include the contribution of the phonon-scattered electrons.


1997 ◽  
Vol 78 (03) ◽  
pp. 1150-1156 ◽  
Author(s):  
Christina Jern ◽  
Heléne Seeman-Lodding ◽  
Bjӧrn Biber ◽  
Ola Winsӧ ◽  
Sverker Jern

SummaryExperimental data indicate large between-organs variations in rates of synthesis of tissue-type plasminogen activator (t-PA), which may reflect important differences in the capacity for constitutive and stimulated t-PA release from the vascular endothelium. In this report we describe a new multiple-organ experimental in vivo model for simultaneous determinations of net release/uptake rates of t-PA across the coronary, splanchnic, pulmonary, and hepatic vascular beds. In eleven intact anesthetized pigs, blood samples were obtained simultaneously from the proximal aorta, coronary sinus, pulmonary artery, and portal and hepatic veins. Plasma flows were monitored separately for each vascular region. Total plasma t-PA was determined by ELISA with a porcine t-PA standard. Regional net release/uptake rates were defined as the product of arteriovenous concentration gradients and local plasma flows. The net release of t-PA across the splanchnic vascular bed was very high, with a mean output of 1,919 ng total t-PA X min-1 (corresponding to 90 ng per min and 100 g tissue). The net coronary t-PA release was 68 ng X min-1 (30 ng X min-1 X 100 g"1)- Pulmonary net fluxes of t-PA were variable without any significant net t-PA release. The net hepatic uptake rate was 4,855 ng X min-1 (436 ng X min-1 X 100 g-1). Net trans-organ changes of active t-PA mirrored those of total t-PA. The results demonstrate marked regional differences in net release rates of t-PA in vivo. The experimental model we present offers new possibilities for evaluation of regional secretion patterns in the intact animal.


2013 ◽  
Vol 19 (1(80)) ◽  
pp. 13-19
Author(s):  
V.A. Shuvalov ◽  
◽  
A.A. Lukenjuk ◽  
N.I. Pismenny ◽  
S.N. Kulagin ◽  
...  

Author(s):  
Nikolai Cherenda ◽  
Andrej K. Kuleshov ◽  
Vitali I. Shymanski ◽  
Vladimir V. Uglov ◽  
N. V. Bibik ◽  
...  

Author(s):  
I. P. Smyaglikov ◽  
N. I. Chubrik ◽  
S.V. Goncharik ◽  
V. V. Azharonok ◽  
L. E. Krat'ko ◽  
...  

Author(s):  
Nikolai N. Cherenda ◽  
Vladimir V. Uglov ◽  
Yu. V. Martinovich ◽  
I. A. Betanov ◽  
Valiantsin M. Astashynski ◽  
...  

2020 ◽  
Author(s):  
Brittany Benlian ◽  
Pavel Klier ◽  
Kayli Martinez ◽  
Marie Schwinn ◽  
Thomas Kirkland ◽  
...  

<p>We report a small molecule enzyme pair for optical voltage sensing via quenching of bioluminescence. This <u>Q</u>uenching <u>B</u>ioluminescent V<u>olt</u>age Indicator, or Q-BOLT, pairs the dark absorbing, voltage-sensitive dipicrylamine with membrane-localized bioluminescence from the luciferase NanoLuc (NLuc). As a result, bioluminescence is quenched through resonance energy transfer (QRET) as a function of membrane potential. Fusion of HaloTag to NLuc creates a two-acceptor bioluminescence resonance energy transfer (BRET) system when a tetramethylrhodamine (TMR) HaloTag ligand is ligated to HaloTag. In this mode, Q-BOLT is capable of providing direct visualization of changes in membrane potential in live cells via three distinct readouts: change in QRET, BRET, and the ratio between bioluminescence emission and BRET. Q-BOLT can provide up to a 29% change in bioluminescence (ΔBL/BL) and >100% ΔBRET/BRET per 100 mV change in HEK 293T cells, without the need for excitation light. In cardiac monolayers derived from human induced pluripotent stem cells (hiPSC), Q-BOLT readily reports on membrane potential oscillations. Q-BOLT is the first example of a hybrid small molecule – protein voltage indicator that does not require excitation light and may be useful in contexts where excitation light is limiting.</p> <p> </p>


2020 ◽  
Author(s):  
Brittany Benlian ◽  
Pavel Klier ◽  
Kayli Martinez ◽  
Marie Schwinn ◽  
Thomas Kirkland ◽  
...  

<p>We report a small molecule enzyme pair for optical voltage sensing via quenching of bioluminescence. This <u>Q</u>uenching <u>B</u>ioluminescent V<u>olt</u>age Indicator, or Q-BOLT, pairs the dark absorbing, voltage-sensitive dipicrylamine with membrane-localized bioluminescence from the luciferase NanoLuc (NLuc). As a result, bioluminescence is quenched through resonance energy transfer (QRET) as a function of membrane potential. Fusion of HaloTag to NLuc creates a two-acceptor bioluminescence resonance energy transfer (BRET) system when a tetramethylrhodamine (TMR) HaloTag ligand is ligated to HaloTag. In this mode, Q-BOLT is capable of providing direct visualization of changes in membrane potential in live cells via three distinct readouts: change in QRET, BRET, and the ratio between bioluminescence emission and BRET. Q-BOLT can provide up to a 29% change in bioluminescence (ΔBL/BL) and >100% ΔBRET/BRET per 100 mV change in HEK 293T cells, without the need for excitation light. In cardiac monolayers derived from human induced pluripotent stem cells (hiPSC), Q-BOLT readily reports on membrane potential oscillations. Q-BOLT is the first example of a hybrid small molecule – protein voltage indicator that does not require excitation light and may be useful in contexts where excitation light is limiting.</p> <p> </p>


1980 ◽  
Vol 45 (1) ◽  
pp. 169-178 ◽  
Author(s):  
František Opekar ◽  
Karel Holub

The galvanostatic dissolution of mercury from the surface of glassy carbon into a thiocyanate solution proceeds in accord with theoretical assumptions, as manifested by the constant product of the dissolution current and transition time. Under certain relations between the amount of oxidised mercury and concentration of thiocyanate at the electrode surface, however, a small part of the mercury dissolves at more positive potentials than correspond to the Nernst equation. This dissolution can be accompanied by potential oscillations. The anomalous behaviour is elucidated by the concept about coverage of a certain part of mercury with a film of sparingly soluble compounds of SCN- ions with mercury. This film is formed at the end of the galvanostatic dissolution on certain places of the electrode surface covered with mercury droplets, where SCN- ions are much exhausted as a result of a high current density.


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