Contributions of Proteoglycans to the Biotransport and Electrical Properties of Articular Cartilage: An Experimental Study

2013 ◽  
Author(s):  
Xin Gao ◽  
Lingtu Meng ◽  
Chun-Yuh C. Huang ◽  
Weiyong Gu
Keyword(s):  
Electrical Properties ◽  
Water Content ◽  
Interstitial Fluid ◽  
Swelling Pressure ◽  
Biomechanical Properties ◽  
Fixed Charge ◽  
Hydraulic Permeability ◽  
Electric Effects ◽  
The Relationship ◽  
Effective Pore Size

Proteoglycans (PGs) are one of the major components in the extracellular matrix (ECM) of cartilage, and are negatively charged due to the charged groups attached to their backbone (i.e., fixed charge groups). PGs play substantial roles in the mechanical, biotransport and electrical events within the tissue.3,7 More specifically, swelling pressure generated by the interaction between fixed charge groups and ionic interstitial fluid enhances cartilage’s capacity of load-bearing. In addition, biotransport properties (e.g., hydraulic permeability) and electrical properties (e.g., electrical conductivity) have been shown to be affected by water content (i.e., porosity) and fixed charge density (FCD).2–4 The alteration of proteoglycan content will affect the tissue FCD and water content, which could cause the changes in biomechanical, biotransport and electrical properties of the cartilage. The relationship between the PG content and biomechanical properties has been widely studied,6,8 but the knowledge on the effects of PG content on biotransport and electrical properties is limited.1 It is not clear whether the dependences of biotransport and electrical properties on PG content are mainly due to electric effects through the FCD associated with PGs or due to hindrance effects related to the effective pore size (i.e., water content) of the tissue. Therefore, the objectives of this study were (1) to investigate the effects of PG content on cartilage biotransport and electrical properties, (2) to analyze whether these effects are caused by changes of water content or FCD.

scholarly journals Isoflurane in Contrast to Propofol Promotes Fluid Extravasation during Cardiopulmonary Bypass in Pigs

2013 ◽  
Vol 119 (4) ◽  
pp. 861-870 ◽  
Author(s):  
Hege Kristin Brekke ◽  
Stig Morten Hammersborg ◽  
Steinar Lundemoen ◽  
Arve Mongstad ◽  
Venny Lise Kvalheim ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Water Content ◽  
Interstitial Fluid ◽  
Outcome Analysis ◽  
Tissue Water Content ◽  
Tissue Water ◽  
Edema Formation ◽  
Fluid Extravasation ◽  
Isoflurane Anesthesia ◽  
Total Tissue

Abstract Background: A highly positive intraoperative fluid balance should be prevented as it negatively impacts patient outcome. Analysis of volume-kinetics has identified an increase in interstitial fluid volume after crystalloid fluid loading during isoflurane anesthesia. Isoflurane has also been associated with postoperative hypoxemia and may be associated with an increase in alveolar epithelial permeability, edema formation, and hindered oxygen exchange. In this article, the authors compare fluid extravasation rates before and during cardiopulmonary bypass (CPB) with isoflurane- versus propofol-based anesthesia. Methods: Fourteen pigs underwent 2 h of tepid CPB with propofol (P-group; n = 7) or isoflurane anesthesia (I-group; n = 7). Fluid requirements, plasma volume, colloid osmotic pressures in plasma and interstitial fluid, hematocrit levels, and total tissue water content were recorded, and fluid extravasation rates calculated. Results: Fluid extravasation rates increased in the I-group from the pre-CPB level of 0.27 (0.13) to 0.92 (0.36) ml·kg−1·min−1, but remained essentially unchanged in the P-group with significant between-group differences during CPB (pb = 0.002). The results are supported by corresponding changes in interstitial colloid osmotic pressure and total tissue water content. Conclusions: During CPB, isoflurane, in contrast to propofol, significantly contributes to a general increase in fluid shifts from the intravascular to the interstitial space with edema formation and a possible negative impact on postoperative organ function.

Hydraulic and diffusional permeabilities of isolated outer medullary descending vasa recta from the rat

1997 ◽  
Vol 272 (1) ◽  
pp. H392-H400 ◽  
Author(s):  
M. R. Turner ◽  
T. L. Pallone
Keyword(s):  
Hydraulic Permeability ◽  
Oncotic Pressure ◽  
Diffusional Permeability ◽  
Vasa Recta ◽  
Reflexion Coefficient ◽  
The Relationship ◽  
Hydrophilic Solutes ◽  
Water Pathway

Water permeates many microvessel walls via a pathway shared with small hydrophilic solutes and also via an exclusive water pathway. In outer medullary descending vasa recta (OMDVR), the relationship between diffusional permeabilities to water and sodium indicates the existence of an exclusive water pathway and suggests that of a shared pathway. We investigated the latter possibility by estimating hydraulic permeability (Lp) and diffusional permeability to [3H]raffinose (P(raf)) in isolated, perfused OMDVR. The product of hydraulic permeability and osmotic reflexion coefficient of albumin (Lp sigma a) was 1.56 +/- 0.19 x 10(-6) cm.s-1.mmHg-1 (n = 28), calculated from transmural volume fluxes induced by perfusate-to-bath differences in albumin oncotic pressure (delta IIa). P(raf) in the same vessels was 40.1 +/- 7.5 x 10(-5) cm/s when delta IIa was zero. In separate experiments, sigma a was at least 0.89 +/- 0.10 (n = 17). Lp sigma a correlates with P(raf), indicating that OMDVR contain a shared pathway for convection driven by delta IIa and for diffusion of small hydrophilic solutes.

Effects of Different Sintering Temperature on the Microstructure and Piezoelectric Properties of Pb(Nb2/3Zn1/3)x(Zr52Ti48)1-XO3 Ceramics

2014 ◽  
Vol 1061-1062 ◽  
pp. 83-86
Author(s):  
Hong Wu ◽  
De Yi Zheng
Keyword(s):  
Electrical Properties ◽  
Electromechanical Coupling ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Electromechanical Coupling Coefficient ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ceramic Samples ◽  
Xrd Patterns ◽  
The Relationship

In this paper, the effects of different sintering temperature on the microstructure and piezoelectric properties of Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3(PNZZT) ceramic samples were investigated. The Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 ceramics materials was prepared by a conventional mixed oxide method. In the period of the experiment, the relationship between crystallographic phase and microstructure were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM) respectively. The XRD patterns shows that all of the ceramic samples are with a tetragonal perovskite structure. Along with sintering temperature increased and the x is 0.03, the grain size gradually become big. Through this experiment, it has been found that when the x is 0.03 and sintered at 1130°C for 2 h, the grains grow well, the grain-boundary intersection of the sample combined well and the porosity of the ceramics decreased, an excellent comprehensive electrical properties of the Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 samples can be obtained. Its best electrical properties are as follows: dielectric constant (ε) is 1105, dielectric loss(tg) is 0.017, electromechanical coupling coefficient (Kp) is 0.287, piezoelectric constant(d33) is 150PC/N

Carbon balance in relation to drying in four epiphytic mosses growing in different vertical ranges

1979 ◽  
Vol 57 (19) ◽  
pp. 1994-1998 ◽  
Author(s):  
Peter L. Tobiessen ◽  
Nancy G. Slack ◽  
Keith A. Mott
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Carbon Balance ◽  
The Other ◽  
Moss Species ◽  
Relationship Of ◽  
The Relationship ◽  
Neckera Pennata ◽  
Lower Water Content ◽  
Photosynthesis And Respiration

The response of photosynthesis and respiration to drying was measured in four species of epiphytic mosses, Ulota crispa (Hedw.) Brid., Neckera pennata Hedw., Anomodon rugellii (C. Mull.) Keissl., and Plagiomnium cuspidatum (Hedw.) T. Kop., from habitats along a desiccation gradient. There was little difference among the mosses in these responses. The relationship of water content to water potential did differ among the mosses, with Plagiomnium, the facultative epiphyte, showing a typical response of more mesic species and the other three showing a more xeric response, i.e., water potential does not begin to fall steeply until a lower water content is reached in Ulota, Neckera, and Anomodon. Both photosynthesis and respiration in all four moss species were quite sensitive to moderate water stress.

Soil Water Characteristic Curve and its Applications in Tunnel

2011 ◽  
Vol 261-263 ◽  
pp. 1039-1043
Author(s):  
Yu You Yang ◽  
Qin Xi Zhang ◽  
Gui He Wang ◽  
Jia Xing Yu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Land Subsidence ◽  
Unsaturated Soil ◽  
Characteristic Curve ◽  
Tunnel Construction ◽  
Coupling Theory ◽  
Engineering Analysis ◽  
Soil Water Characteristic Curve ◽  
The Relationship

A soil water characteristic curve (SWCC) can describe the relationship between unsaturated soil matric suction and water content. By analyzing and researching the test data of the soil water characteristic curve researchers can initially establish the SWCC equation and apply this equation to the actual engineering analysis. In another words, this article is based on the fluid-solid coupling theory of unsaturated soil used to analyze and study the problem of land subsidence caused by tunnel construction. Numerical calculations show that the coupling results agree well with the measured curve works.

Laboratory test of snow wetness influence on electrical conductivity measured with ground penetrating radar

2009 ◽  
Vol 40 (1) ◽  
pp. 33-44 ◽  
Author(s):  
Nils Granlund ◽  
Angela Lundberg ◽  
James Feiccabrino ◽  
David Gustafsson
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Laboratory Test ◽  
Liquid Water ◽  
Ground Penetrating Radar ◽  
Wave Attenuation ◽  
Radar Measurements ◽  
Ground Penetrating ◽  
Radar Wave ◽  
The Relationship

Ground penetrating radar operated from helicopters or snowmobiles is used to determine snow water equivalent (SWE) for annual snowpacks from radar wave two-way travel time. However, presence of liquid water in a snowpack is known to decrease the radar wave velocity, which for a typical snowpack with 5% (by volume) liquid water can lead to an overestimation of SWE by about 20%. It would therefore be beneficial if radar measurements could also be used to determine snow wetness. Our approach is to use radar wave attenuation in the snowpack, which depends on electrical properties of snow (permittivity and conductivity) which in turn depend on snow wetness. The relationship between radar wave attenuation and these electrical properties can be derived theoretically, while the relationship between electrical permittivity and snow wetness follows a known empirical formula, which also includes snow density. Snow wetness can therefore be determined from radar wave attenuation if the relationship between electrical conductivity and snow wetness is also known. In a laboratory test, three sets of measurements were made on initially dry 1 m thick snowpacks. Snow wetness was controlled by stepwise addition of water between radar measurements, and a linear relationship between electrical conductivity and snow wetness was established.

scholarly journals Ichthyometry and electrical bioimpedance analysis to estimate the body composition of tambatinga

2014 ◽  
Vol 44 (2) ◽  
pp. 279-286 ◽  
Author(s):  
Francisco Teixeira Andrade ◽  
Márvio Lobão Teixeira de Abreu ◽  
João Batista Lopes ◽  
Agustinho Valente de Figueiredo ◽  
Maria de Nazaré Bona Alencar Araripe ◽  
...  
Keyword(s):  
Body Composition ◽  
Water Content ◽  
Correlation Coefficients ◽  
Bioelectrical Impedance ◽  
Impedance Analysis ◽  
The Body ◽  
Composition Analysis ◽  
Average Weight ◽  
Electrical Bioimpedance ◽  
The Relationship

Body composition analysis is relevant to characterize the nutritional requirements and finishing phase of fish. The aim of this study was to investigate the relationship between ichthyometric (weight, total and standard length, density and yields), bromatological (fat, protein, ash and water content) and bioelectrical-impedance-analysis (BIA) (resistance, reactance, phase angle and composition indexes) variables in the hybrid tambatinga (Colossoma macropomum × Piaractus brachypomus). In a non-fertilized vivarium, 520 juveniles were housed and fed commercial rations. Then, 136 days after hatching (DAH), 15 fish with an average weight of 37.69 g and average total length of 12.96 cm were randomly chosen, anesthetized (eugenol) and subjected to the first of fourteen fortnightly assessments (BIA and biometry). After euthanasia, the following parts were weighed: whole carcass with the head, fillet, and skin (WC); fillet with skin (FS); and the remainder of the carcass with the head (CH). Together, FS and CH were ground and homogenized for the bromatological analyses. Estimates of the body composition and yields of tambatinga, with models including ichthyometric and BIA variables, showed correlation coefficients ranging from 0.81 (for the FS yield) to 1,00 (for the total ash). Similarly, models that included only BIA variables had correlation coefficients ranging from 0.81 (FS and CH yields) to 0.98 (for the total ash). Therefore, in tambatinga, the BIA technique allows the estimation of the yield of the fillet with skin and the body composition (water content, fat, ash, and protein). The best models combine ichthyometric and BIA variables.

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