scholarly journals Surface wave elastography is a reliable method to correlate muscle elasticity, torque, and electromyography activity level

2021 ◽  
Vol 9 (15) ◽  
Author(s):  
Gustavo A. Grinspan ◽  
Hélio V. Cabral ◽  
Leonardo M. L. Souza ◽  
Liliam F. Oliveira ◽  
Sofía Aguiar ◽  
...  
Keyword(s):  
Surface Wave ◽  
Reliable Method ◽  
Activity Level ◽  
Muscle Elasticity

A Fast and Reliable Method for Surface Wave Tomography

2001 ◽  
Vol 158 (8) ◽  
pp. 1351-1375 ◽  
Author(s):  
M. P. Barmin ◽  
M. H. Ritzwoller ◽  
A. L. Levshin
Keyword(s):  
Surface Wave ◽  
Reliable Method ◽  
Surface Wave Tomography ◽  
Wave Tomography

Quantitative Diameter Measurements of Chromatin and TMV Fibers in the Freeze-Dried State

1988 ◽  
Vol 46 ◽  
pp. 170-171
Author(s):  
B. D. Athey ◽  
A. L. Stout ◽  
M. F. Smith ◽  
J. P. Langmore
Keyword(s):  
Reliable Method ◽  
Fiber Diameter ◽  
Quantitative Agreement ◽  
One Dimension ◽  
Fiber Axis ◽  
Two Dimensional ◽  
Fiber Density ◽  
Variable Diameter ◽  
Freeze Dried ◽  
Expected Values

Although there is general agreement that Inactive chromosome fibers consist of helically packed nucleosomes, the pattern of packing is still undetermined. Only one of the proposed models, the crossed-linker model, predicts a variable diameter dependent on the length of DNA between nucleosomes. Measurements of the fiber diameter of negatively-stained and frozen- hydrated- chromatin from Thyone sperm (87bp linker) and Necturus erythrocytes (48bp linker) have been previously reported from this laboratory. We now introduce a more reliable method of measuring the diameters of electron images of fibrous objects. The procedure uses a modified version of the computer program TOTAL, which takes a two-dimensional projection of the fiber density (represented by the micrograph itself) and projects it down the fiber axis onto one dimension. We illustrate this method using high contrast, in-focus STEM images of TMV and chromatin from Thyone and Necturus. The measured diameters are in quantitative agreement with the expected values for the crossed-linker model for chromatin structure

Exit-surface wave reconstruction using a focal series

1992 ◽  
Vol 50 (2) ◽  
pp. 988-989
Author(s):  
W.J. de Ruijter ◽  
M.R. McCartney ◽  
David J. Smith ◽  
J.K. Weiss
Keyword(s):  
Surface Wave ◽  
Spherical Aberration ◽  
Data Extraction ◽  
High Sensitivity ◽  
Geometric Distortion ◽  
Variation Method ◽  
Objective Lens ◽  
Immediate Reconstruction ◽  
Exit Surface ◽  
Electron Microscopes

Further advances in resolution enhancement of transmission electron microscopes can be expected from digital processing of image data recorded with slow-scan CCD cameras. Image recording with these new cameras is essential because of their high sensitivity, extreme linearity and negligible geometric distortion. Furthermore, digital image acquisition allows for on-line processing which yields virtually immediate reconstruction results. At present, the most promising techniques for exit-surface wave reconstruction are electron holography and the recently proposed focal variation method. The latter method is based on image processing applied to a series of images recorded at equally spaced defocus.Exit-surface wave reconstruction using the focal variation method as proposed by Van Dyck and Op de Beeck proceeds in two stages. First, the complex image wave is retrieved by data extraction from a parabola situated in three-dimensional Fourier space. Then the objective lens spherical aberration, astigmatism and defocus are corrected by simply dividing the image wave by the wave aberration function calculated with the appropriate objective lens aberration coefficients which yields the exit-surface wave.

Specificity determinants of phosphoprotein phosphatases controlling kinetochore functions

2020 ◽  
Vol 64 (2) ◽  
pp. 325-336 ◽  
Author(s):  
Dimitriya H. Garvanska ◽  
Jakob Nilsson
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Activity Level ◽  
Phosphorylation Sites ◽  
Binding Affinities ◽  
Mitotic Kinases ◽  
Anaphase Onset ◽  
Phosphoprotein Phosphatases ◽  
Linear Motifs ◽  
Temporal And Spatial ◽  
Kinetochore Function

Abstract Kinetochores are instrumental for accurate chromosome segregation by binding to microtubules in order to move chromosomes and by delaying anaphase onset through the spindle assembly checkpoint (SAC). Dynamic phosphorylation of kinetochore components is key to control these activities and is tightly regulated by temporal and spatial recruitment of kinases and phosphoprotein phosphatases (PPPs). Here we focus on PP1, PP2A-B56 and PP2A-B55, three PPPs that are important regulators of mitosis. Despite the fact that these PPPs share a very similar active site, they target unique ser/thr phosphorylation sites to control kinetochore function. Specificity is in part achieved by PPPs binding to short linear motifs (SLiMs) that guide their substrate specificity. SLiMs bind to conserved pockets on PPPs and are degenerate in nature, giving rise to a range of binding affinities. These SLiMs control the assembly of numerous substrate specifying complexes and their position and binding strength allow PPPs to target specific phosphorylation sites. In addition, the activity of PPPs is regulated by mitotic kinases and inhibitors, either directly at the activity level or through affecting PPP–SLiM interactions. Here, we discuss recent progress in understanding the regulation of PPP specificity and activity and how this controls kinetochore biology.

Surface Wave Utility in Composite Materia] Characterization

1989 ◽  
Vol 1 (1) ◽  
pp. 247-265
Author(s):  
Joseph Rose ◽  
Aleksander Pilarski ◽  
Yimei Huang
Keyword(s):  
Surface Wave

Self-Referent Thoughts in Exercise: The Self-Perception in Exercise Questionnaire

1997 ◽  
Vol 13 (3) ◽  
pp. 195-205 ◽  
Author(s):  
Marit Sorensen
Keyword(s):  
Physical Activity ◽  
Pilot Study ◽  
Physical Activity Level ◽  
Convergent Validity ◽  
English Language ◽  
Lifestyle Changes ◽  
Activity Level ◽  
Language Version ◽  
Social Comfort ◽  
And Gender

Adherence to lifestyle changes - beginning to exercise, for example - is assumed to be mediated by self-referent thoughts. This paper describes a pilot study and three studies conducted to develop and validate a questionnaire for adults to determine their self-perceptions related to health-oriented exercise. The pilot study identified items pertinent to the domains considered important in this context, and began the process of selecting items. Study 2 examined the factor structure, reduced the number of items, determined the internal consistency of the factors, and explored the discriminative validity of the questionnaire as to physical activity level and gender. Four factors with a total of 24 items were accepted, measuring mastery of exercise, body perception, social comfort/discomfort in the exercise setting, and perception of fitness. All subscales had acceptable internal consistencies. Preliminary validity was demonstrated by confirming hypothesized differences in scores as to gender, age, and physical activity level. The third study examined and demonstrated convergent validity with similar existing subscales. The fourth study examined an English-language version of the questionnaire, confirming the existence of the factors and providing preliminary psychometric evidence of the viability of the questionnaire.

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