A phase-locked echo tracking system for recording arterial diameter changes in vivo.

To demonstrate axial artery motion during the cardiac cycle, the common carotid arteries (CCA) of 10 pigs were exposed and equipped with piezoelectric crystals sutured onto the artery as axial position detectors. An echo-tracking system was used to simultaneously measure the CCA diameter. For each animal, data for pressure, length, and diameter were collected at a frequency of 457 Hz. At a mean pulse pressure of 33 ± 8 mmHg, the mean systolodiastolic length difference was 0.3 ± 0.01 mm for a mean arterial segment of 11.35 ± 1.25 mm. Systolic and diastolic diameters were 4.1 ± 0.3 and 3.9 ± 0.2 mm, respectively. The examined CCA segment displayed a mean axial systolic shortening of 2.7%. This study clearly demonstrates, for the first time, that the length of a segment of the CCA changes during the cardiac cycle and that this movement is inversely correlated with pulse pressure. It is also apparent that the segmental axial strain is significantly smaller than the diameter variation during the cardiac cycle and that the impact of the axial strain for compliance computation should be further evaluated.

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Cantilever transducer for continuous measurement of arterial diameter in vivo

Journal of Applied Physiology ◽

10.1152/jappl.1971.31.6.948 ◽

1971 ◽

Vol 31 (6) ◽

pp. 948-953 ◽

Cited By ~ 19

Author(s):

J. P. Murgo ◽

R. H. Cox ◽

L. H. Peterson

Keyword(s):

Continuous Measurement ◽

Arterial Diameter

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Accuracy and repeatability of wrist joint angles in boxing using an electromagnetic tracking system

Sports Engineering ◽

10.1007/s12283-019-0313-6 ◽

2019 ◽

Vol 23 (1) ◽

Cited By ~ 1

Author(s):

Ian T. Gatt ◽

Tom Allen ◽

Jon Wheat

Keyword(s):

Wrist Joint ◽

Tracking System ◽

Testing Procedure ◽

Electromagnetic Tracking ◽

Good Reliability ◽

Flexion Extension ◽

In Vivo Testing ◽

Accuracy And Repeatability ◽

Electromagnetic Tracking System

AbstractThe hand-wrist region is reported as the most common injury site in boxing. Boxers are at risk due to the amount of wrist motions when impacting training equipment or their opponents, yet we know relatively little about these motions. This paper describes a new method for quantifying wrist motion in boxing using an electromagnetic tracking system. Surrogate testing procedure utilising a polyamide hand and forearm shape, and in vivo testing procedure utilising 29 elite boxers, were used to assess the accuracy and repeatability of the system. 2D kinematic analysis was used to calculate wrist angles using photogrammetry, whilst the data from the electromagnetic tracking system was processed with visual 3D software. The electromagnetic tracking system agreed with the video-based system (paired t tests) in both the surrogate (< 0.2°) and quasi-static testing (< 6°). Both systems showed a good intraclass coefficient of reliability (ICCs > 0.9). In the punch testing, for both repeated jab and hook shots, the electromagnetic tracking system showed good reliability (ICCs > 0.8) and substantial reliability (ICCs > 0.6) for flexion–extension and radial-ulnar deviation angles, respectively. The results indicate that wrist kinematics during punching activities can be measured using an electromagnetic tracking system.

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In Vitro and In Vivo Assessment of a New Workflow for the Acquisition of Mandibular Kinematics Based on Portable Tracking System with Passive Optical Reflective Markers

Applied Sciences ◽

10.3390/app11093947 ◽

2021 ◽

Vol 11 (9) ◽

pp. 3947

Author(s):

Marco Farronato ◽

Gianluca M. Tartaglia ◽

Cinzia Maspero ◽

Luigi M. Gallo ◽

Vera Colombo

Keyword(s):

Measurement Error ◽

Tracking System ◽

Intraclass Correlation ◽

Optical Tracking ◽

Optical Tracking System ◽

Rater Reliability ◽

Tracking Device ◽

Mandibular Kinematics

Clinical use of portable optical tracking system in dentistry could improve the analysis of mandibular movements for diagnostic and therapeutic purposes. A new workflow for the acquisition of mandibular kinematics was developed. Reproducibility of measurements was tested in vitro and intra- and inter-rater repeatability were assessed in vivo in healthy volunteers. Prescribed repeated movements (n = 10) in three perpendicular directions of the tracking-device coordinate system were performed. Measurement error and coefficient of variation (CV) among repetitions were determined. Mandibular kinematics of maximum opening, left and right laterality, protrusion and retrusion of five healthy subjects were recorded in separate sessions by three different operators. Obtained records were blindly examined by three observers. Intraclass correlation coefficient (ICC) was calculated to estimate inter-rater and intra-rater reliability. Maximum in vitro measurement error was 0.54 mm and CV = 0.02. Overall, excellent intra-rater reliability (ICC > 0.90) for each variable, general excellent intra-rater reliability (ICC = 1.00) for all variables, and good reliability (ICC > 0.75) for inter-rater tests were obtained. A lower score was obtained for retrusion with “moderate reliability” (ICC = 0.557) in the inter-rater tests. Excellent repeatability and reliability in optical tracking of primary movements were observed using the tested portable tracking device and the developed workflow.

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Establishment and Identification of a CiPSC Lineage Reprogrammed from FSP-tdTomato Mouse Embryonic Fibroblasts (MEFs)

Stem Cells International ◽

10.1155/2018/5965727 ◽

2018 ◽

Vol 2018 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Ruiping Chen ◽

Wenxiu Xie ◽

Baomei Cai ◽

Yue Qin ◽

Chuman Wu ◽

...

Keyword(s):

Stem Cells ◽

Small Molecule ◽

Fluorescent Protein ◽

Day Treatment ◽

Tracking System ◽

Embryonic Stem ◽

Mouse Embryonic Fibroblasts ◽

Embryonic Fibroblasts ◽

Underlying Mechanisms

Safety issues associated with transcription factors or viruses may be avoided with the use of chemically induced pluripotent stem cells (CiPSCs), thus promoting their clinical application. Previously, we had successfully developed and standardized an induction method using small-molecule compound, with simple operation, uniform induction conditions, and clear constituents. In order to verify that the CiPSCs were indeed reprogrammed from mouse embryonic fibroblasts (MEFs), and further explore the underlying mechanisms, FSP-tdTomato mice were used to construct a fluorescent protein-tracking system of MEFs, for revealing the process of CiPSC reprogramming. CiPSCs were identified by morphological analysis, mRNA, and protein expression of pluripotency genes, as well as teratoma formation experiments. Results showed that after 40-day treatment of tdTomato-MEFs with small-molecule compounds, the cells were presented with prominent nucleoli, high core-to-cytoplasmic ratio, round shape, group and mass arrangement, and high expression of pluripotency gene. These cells could differentiate into three germ layer tissues in vivo. As indicated by the above results, tdTomato-MEFs could be reprogrammed into CiPSCs, a lineage that possesses pluripotency similar to mouse embryonic stem cells (mESCs), with the use of small-molecule compounds. The establishment of CiPSC lineage, tracked by fluorescent protein, would benefit further studies exploring its underlying mechanisms. With continuous expression of fluorescent proteins during cellular differentiation, this cell lineage could be used for tracking CiPSC transplantation and differentiation into functional cells.

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ShearFAST: a user-friendly in vitro toolset for high throughput, inexpensive fluid shear stress experiments.

10.1101/2020.01.31.929513 ◽

2020 ◽

Author(s):

Thomas Brendan Smith ◽

Alessandro Marco De Nunzio ◽

Kamlesh Patel ◽

Haydn Munford ◽

Tabeer Alam ◽

...

Keyword(s):

Shear Stress ◽

High Throughput ◽

Fluid Shear Stress ◽

Tracking System ◽

Frequency Measurement ◽

Camera Motion ◽

Fluid Shear ◽

Mean Frequency

Fluid shear stress is a key modulator of cellular physiology in vitro and in vivo, but its effects are under-investigated due to requirements for complicated induction methods. Herein we report the validation of ShearFAST; a smartphone application that measures the rocking profile on a standard laboratory cell rocker and calculates the resulting shear stress arising in tissue culture plates. The accuracy with which this novel approach measured rocking profiles was validated against a graphical analysis, and also against measures reported by an 8-camera motion tracking system. ShearFASTs angle assessments correlated well with both analyses (r ≥0.99, p ≤0.001) with no significant differences in pitch detected across the range of rocking angles tested. Rocking frequency assessment by ShearFAST also correlated well when compared to the two independent validatory techniques (r ≥0.99, p ≤0.0001), with excellent reproducibility between ShearFAST and video analysis (mean frequency measurement difference of 0.006 ± 0.005Hz) and motion capture analysis (mean frequency measurement difference of 0.008 ± 0.012Hz). These data make the ShearFAST assisted cell rocker model make it an attractive approach for economical, high throughput fluid shear stress experiments. Proof of concept data presented reveals a protective effect of low-level shear stress on renal proximal tubule cells submitted to simulations of pretransplant storage.

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Effects of alpha-adrenergic stimuli on mesenteric collecting lymphatics in the rate

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1997.273.1.r331 ◽

1997 ◽

Vol 273 (1) ◽

pp. R331-R336 ◽

Cited By ~ 6

Author(s):

J. N. Benoit

Keyword(s):

Smooth Muscle ◽

Stroke Volume ◽

Contractile Activity ◽

Tracking System ◽

Video Tracking ◽

Sprague Dawley ◽

Shortening Velocity ◽

Adrenoceptor Agonist ◽

Lymphatic Pumping

The present study examined the effects of alpha 1- and alpha 2-adrenergic stimuli on rat mesenteric collecting lymphatics in vivo. Sprague-Dawley rats were anesthetized, and the mesentery was prepared for intravital microscopic study. Mesenteric collecting lymphatic diameter was continuously monitored by using a computerized video tracking system, and indexes of lymphatic pumping (e.g., contraction frequency, stroke volume, ejection fraction, and muscle shortening velocity) were determined from the diameter record. Contractile activity was monitored before and during the administration of various adrenergic agonists and antagonists. The receptor antagonists prazosin (alpha 1) and yohimbine (alpha 2) did not significantly alter baseline diameter or contractile activity, which suggests that lymphatics possess no basal adrenergic tone. Norepinephrine and phenylephrine (01-1.0 microM) produced dose-dependent increases in frequency and decreases in diameter. Lymphatic pump flow increased in direct proportion to frequency, because stroke volume did not change. The changes in lymphatic pumping produced by 1 microM norepinephrine were completely blocked by prazosin or phentolamine and only partially blocked by yohimbine. The alpha 2-adrenoceptor agonist (alpha-methyl-norepinephrine) produced no changes in lymphatic activity. This latter observation suggests that a role for postjunctional alpha 2-adrenoceptors in modulating mesenteric lymphatic smooth muscle is unlikely. The results of these studies support the existence of alpha-adrenoceptors on lymphatic smooth muscle. It is concluded that conditions characterized by increased sympathetic outflow may augment lymphatic function through alpha 1- but not alpha 2-adrenoceptors.

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