In vivo measurements of the internal pH of Hediste ( Nereis ) diversicolor (Annelida, Polychaeta) exposed to ambient sulphidic conditions using pH microelectrodes

2000 ◽  
Vol 87 (6) ◽  
pp. 283-287 ◽  
Author(s):  
Stefan Sommer ◽  
Andreas Jahn ◽  
Friederike Funke ◽  
Nils Brenke
Keyword(s):  
Nereis Diversicolor ◽  
In Vivo Measurements ◽  
Internal Ph ◽  
Ph Microelectrodes

scholarly journals Simulating a Ground Truth for Transit Time Analysis of Indicator Dilution Curves

2020 ◽  
Vol 6 (3) ◽  
pp. 268-271
Author(s):  
Michael Reiß ◽  
Ady Naber ◽  
Werner Nahm
Keyword(s):  
Transit Time ◽  
Sampling Rate ◽  
Ground Truth ◽  
Indicator Dilution ◽  
Cross Sectional ◽  
In Vivo Measurements ◽  
Multiple Indicator Dilution ◽  
Transit Times ◽  
Dilution Curves

AbstractTransit times of a bolus through an organ can provide valuable information for researchers, technicians and clinicians. Therefore, an indicator is injected and the temporal propagation is monitored at two distinct locations. The transit time extracted from two indicator dilution curves can be used to calculate for example blood flow and thus provide the surgeon with important diagnostic information. However, the performance of methods to determine the transit time Δt cannot be assessed quantitatively due to the lack of a sufficient and trustworthy ground truth derived from in vivo measurements. Therefore, we propose a method to obtain an in silico generated dataset of differently subsampled indicator dilution curves with a ground truth of the transit time. This method allows variations on shape, sampling rate and noise while being accurate and easily configurable. COMSOL Multiphysics is used to simulate a laminar flow through a pipe containing blood analogue. The indicator is modelled as a rectangular function of concentration in a segment of the pipe. Afterwards, a flow is applied and the rectangular function will be diluted. Shape varying dilution curves are obtained by discrete-time measurement of the average dye concentration over different cross-sectional areas of the pipe. One dataset is obtained by duplicating one curve followed by subsampling, delaying and applying noise. Multiple indicator dilution curves were simulated, which are qualitatively matching in vivo measurements. The curves temporal resolution, delay and noise level can be chosen according to the requirements of the field of research. Various datasets, each containing two corresponding dilution curves with an existing ground truth transit time, are now available. With additional knowledge or assumptions regarding the detection-specific transfer function, realistic signal characteristics can be simulated. The accuracy of methods for the assessment of Δt can now be quantitatively compared and their sensitivity to noise evaluated.

In vivo measurements of glenohumeral distraction technique performed in three different joint positions

2021 ◽  
pp. 1-7
Author(s):  
Diego Guerra-Rodríguez ◽  
Liliana Rozo ◽  
Daniel Basilio ◽  
Juan Guerrero-Henriquez
Keyword(s):  
In Vivo Measurements

scholarly journals Effects of cytoplasmic acidification on clathrin lattice morphology.

1989 ◽  
Vol 108 (2) ◽  
pp. 401-411 ◽  
Author(s):  
J Heuser
Keyword(s):  
Plasma Membrane ◽  
Cultured Cells ◽  
Membrane Receptors ◽  
The Other ◽  
Culture Dish ◽  
Initial Curvature ◽  
Internal Ph ◽  
Cytoplasmic Acidification

Reducing the internal pH of cultured cells by several different protocols that block endocytosis is found to alter the structure of clathrin lattices on the inside of the plasma membrane. Lattices curve inward until they become almost spherical yet remain stubbornly attached to the membrane. Also, the lattices bloom empty "microcages" of clathrin around their edges. Correspondingly, broken-open cells bathed in acidified media demonstrate similar changes in clathrin lattices. Acidification accentuates the normal tendency of lattices to round up in vitro and also stimulates them to nucleate microcage formation from pure solutions of clathrin. On the other hand, several conditions that also inhibit endocytosis have been found to create, instead of unusually curved clathrin lattices with extraneous microcages, a preponderance of unusually flat lattices. These treatments include pH-"clamping" cells at neutrality with nigericin, swelling cells with hypotonic media, and sticking cells to the surface of a culture dish with soluble polylysine. Again, the unusually flat lattices in such cells display a tendency to round up and to nucleate clathrin microcage formation during subsequent in vitro acidification. This indicates that regardless of the initial curvature of clathrin lattices, they all display an ability to grow and increase their curvature in vitro, and this is enhanced by lowering ambient pH. Possibly, clathrin lattice growth and curvature in vivo may also be stimulated by a local drop in pH around clusters of membrane receptors.

In Vivo Measurements On Human Lens Using Quasielastic Light Scattering

1987 ◽  
Author(s):  
Peter C. Magnante ◽  
Leo T. Chylack ◽  
George B. Benedek ◽  
Teodosio Libondi ◽  
Stephen N. Joffe ◽  
...  
Keyword(s):  
Light Scattering ◽  
Human Lens ◽  
Quasielastic Light Scattering ◽  
In Vivo Measurements

Patient-individual local SAR determination: In vivo measurements and numerical validation

2011 ◽  
Vol 68 (4) ◽  
pp. 1117-1126 ◽  
Author(s):  
T. Voigt ◽  
H. Homann ◽  
U. Katscher ◽  
O. Doessel
Keyword(s):  
Numerical Validation ◽  
In Vivo Measurements ◽  
Local Sar
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