Microstructural Mechanics of Collagen Gels in Confined Compression: Poroelasticity, Viscoelasticity, and Collapse

2004 ◽  
Vol 126 (2) ◽  
pp. 152-166 ◽  
Author(s):  
Preethi L. Chandran ◽  
Victor H. Barocas
Keyword(s):  
In Vitro Study ◽  
Material Point ◽  
Interstitial Flow ◽  
Collagen Gels ◽  
Confined Compression ◽  
Collagen Concentration ◽  
Point Tracking ◽  
Stress Variations

Background: Collagen gels are important as platforms for in vitro study of cell behavior and as prototypical bioartificial tissues, but their mechanical behavior, particularly on the microscopic scale, is still poorly understood. Method of Approach: Collagen gels were studied in step (10% strain in 0.05 s) and ramp (0.1%/s strain rate for 100 s) confined compression. Real-time birefringence mapping gave the local collagen concentration and orientation along with piston stress. Variations in the retardation allowed material-point tracking and qualitative determination of the strain distribution. Results: Ramp tests showed classical poroelastic behavior: compression near the piston and relaxation to a uniform state. Step tests, however, showed an irreversibly collapsed region near the piston. Conclusions: Our results suggest that interstitial flow and fibril bending at crosslinks are the dominant mechanical processes during compression, and that fibril bending is reversible before collapse.

scholarly journals Determination of the maximum inhibitory dilution of cetylpyridinium chloride-based mouthwashes against staphylococcus aureus: an in vitro study

2008 ◽  
Vol 16 (4) ◽  
pp. 275-279 ◽  
Author(s):  
Evandro Watanabe ◽  
Juliane Maria Guerreiro Tanomaru ◽  
Andresa Piacezzi Nascimento ◽  
Fumio Matoba-Júnior ◽  
Mario Tanomaru-Filho ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cetylpyridinium Chloride ◽  
In Vitro Study ◽  
Vitro Study

Determination of coefficient of friction between the equine foot and different ground surfaces: an in vitro study

2006 ◽  
Vol 3 (4) ◽  
pp. 191-198 ◽  
Author(s):  
Nicolas J Vos ◽  
Dirk J Riemersma
Keyword(s):  
Coefficient Of Friction ◽  
Force Plate ◽  
Ground Surface ◽  
In Vitro Study ◽  
Gravity Force ◽  
Uniform Motion ◽  
The Coefficient Of Friction ◽  
Equine Industry

AbstractSlippery surfaces are a continuous concern in equine veterinary practice during both treatment and orthopaedic work-ups, especially when horses have to trot on circles. Sliding of the equine foot on the ground with the potential of injury is prevented if the horizontally acting accelerating or decelerating forces on the foot do not exceed maximal friction. Friction can be calculated and therefore anticipated if the coefficient of friction (μ) between the foot of the horse and the particular ground surface is known. Friction between shod and unshod cadaver equine hooves and different ground surfaces (concrete, tarmac and rubber) was determined by pulling the hooves horizontally in a uniform motion. Horizontal forces (Fh) were measured on a force plate and with a portable digital electronic force meter. The coefficient of friction (μ) was calculated as the quotient between Fh and the gravity force (N) of the object, hence: μ = Fh /N. This study has shown that the coefficient of friction between equine hooves and a specific ground surface can be determined using a portable digital force meter or a force plate. Friction significantly depended not only on the type of surface but also on shoeing of the equine foot. Bare feet showed more friction with the hard surfaces (bricks and tarmac), the shod feet showing more friction with the rubber surfaces. Coefficients of friction could be used to estimate the possibility of injuries occurring in the equine industry during exercise and/or lameness or pre-purchase examinations.

DEVELOPMENT OF A SPECIFIC RADIODMMUNOASSAY FOR DETERMINATION OF PEPTIDES DERIVED FROM HUMAN LEUKOCYTE ELASTASE DEGRADATION OF HUMAN FIBRIN (OGEN)

1987 ◽  
Author(s):  
R Wallin ◽  
T Saldeen
Keyword(s):  
Human Leukocyte ◽  
In Vitro Study ◽  
Molecular Size ◽  
Molar Ratio ◽  
Leukocyte Elastase ◽  
Severe Renal Failure ◽  
Human Leukocyte Elastase ◽  
Edta Plasma

This paper describes a RIA for determination of the vasoactive peptide BB 30-43 and related peptides derived from leukocyte elastase degradaticn of human fibrin(ogen). The peptide was synthesized and could easily be labelled with 125I.Rabbits were iirmunized with BB 30-43 conjugated to bovine albumin. The antibody was found to bind about 5C% of the tracer in absence of BB 30-43 in a ˜1/800 diluticn. The RIA can detect peptide concentrations between 50 - 25000 pmol/L. The crossreaction with fibrinogen is very low (<0.001%) and with plas-min derived fibrin(ogen) peptides Bβ 1-42 and BB 15-42 also low (<0.2%). Plasma samples can be analyzed without any pretreatment. In an in vitro study fibrin and fibrincgen was degraded with plasmin or leukocyte elastase. Plasmin degradaticn of fibrin and fibrincgen did not release peptides which cross-reacted with our antibody, whereas leukocyte elastase degradation released peptides from both fibrin and fibrinogen which crossreact whith the antibody.The imnunolqgical activity was not changed after degrading peptide Bβ 30-43 with a) trypsin, b) plasmin, c) batraxobin, d) thrombin, e) elastase, at +37°,1 h, in a molar ratio of 1:100. Even degradaticn by elastase (1:3.5) +37°, 1 h, did not destroy the iirmunological activity.The imriunolcgical stability of peptide B< 30-43 in EDTA-plasma (+37°) seems to be very good. In citrated and heparinized plasma the activity of this peptide seems to vanish quite fast. In spite of these results we have detected high levels of iirmunolcgical activitiy in citrated or heparinized patient plasma. The molecular distribution of the peptides detected in plasma by our RIA corresponded to a fragnent containing about 25 amino acids. This fragnent seemes to be rather stable in plasma. When this fragnent was degraded with elastase in vitro a peptide with a molecular size resembling BB 30-43 was obtained. Over 300 patient samples have been studied. About 20 per cent were positive and the highest levels were found in patients with ARDS, septicaemia, severe renal failure, pulmonary embolism, pneumonia and pulmonary congestion.

Feasibility of near Infrared Spectroscopy Determination of Haemoglobin-Related Blood Levels of Cattle: An in vitro Study

NIR news ◽  
2012 ◽  
Vol 23 (6) ◽  
pp. 13-14 ◽  
Author(s):  
Akifumi Ikehata ◽  
Kunio Sashida ◽  
Shanji Park ◽  
Tsutomu Okura ◽  
Yutaka Terada
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
In Vitro Study ◽  
Vitro Study ◽  
Blood Levels

scholarly journals Determination of dose enhancement caused by AuNPs with Xoft® Axxent® Electronic (eBx™) and conventional brachytherapy: in vitro study

2018 ◽  
Vol Volume 13 ◽  
pp. 5733-5741 ◽  
Author(s):  
Elham Shahhoseini ◽  
Prabhakar Ramachandran ◽  
William Patterson ◽  
Moshi Geso
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Dose Enhancement

scholarly journals The determination of the initial straight length in root canals of mandibular premolars -an in vitro study

2009 ◽  
Vol 14 (2) ◽  
pp. 85 ◽  
Author(s):  
B Willershausen ◽  
A Kasaj ◽  
B Röhrig ◽  
B Briseño
Keyword(s):  
In Vitro Study ◽  
Vitro Study ◽  
Root Canals

scholarly journals DETERMINATION OF THE HYDROLYTIC ACTIVITY OF WHOLE SALIVA USING CHITOSAN ASCORBATE AS A SUBSTRATE

2018 ◽  
Vol XXIII ◽  
pp. 97-102
Author(s):  
Barbara Kochańska ◽  
Mirela Łukaszewska ◽  
Jolanta Ochocińska
Keyword(s):  
Ascorbic Acid ◽  
In Vitro Study ◽  
Hydrolytic Activity ◽  
Vitro Study ◽  
Whole Saliva ◽  
Unstimulated Whole Saliva

The aim of this work was to evaluate of hydrolytic activity of whole saliva using chitosan ascorbate as a substrate. In this aim, the concentrations of N-acetyl-D-glucosamine were determined in saliva before addition of chitosan ascorbate, directly after addition and during incubation with chitosan ascorbate by 20 hrs. In this in vitro study were used sterile chitosan ascorbate in the form of powder. Chitosan was obtained from krill chitin. The ratio of ascorbic acid to chitosan was 1:1. The unstimulated whole saliva showed the hydrolytic activity in the presence of the chitosan ascorbate as a substrate.

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