A Method for Determining the Strain-Time Endurance of Cells in Planar Tissue-Engineered Constructs Subjected to Large Compressive Deformations

2008 ◽  
Author(s):  
Amit Gefen ◽  
Bastiaan van Nierop ◽  
Dan L. Bader ◽  
Cees W. Oomens
Keyword(s):  
Experimental Method ◽  
Artificial Muscle ◽  
Normal Growth ◽  
Mechanical Environment ◽  
Time Threshold ◽  
Chronic Injuries ◽  
Time Periods ◽  
Murine Skeletal Muscle ◽  
And Function ◽  
Substantial Interest

The mechanical environment of cells influences their normal growth and function, and may also affect the development of diseases and chronic injuries. Accordingly, there is substantial interest in determining the endurance of cells subjected to controlled mechanical strains for given time periods. A standardized, generic experimental method for determining strain-time thresholds for cell death is so far missing in the literature. In this study, a new experimental method was developed to measure strain-time thresholds of cells in planar tissue-engineered constructs subjected to large compressive strains. The method was applied to measure a strain-time threshold for differentiated C2C12 murine skeletal muscle cells in tissue-engineered bio-artificial muscle (BAM) constructs.

scholarly journals Life-course burden of health deficits associates with later-life heart size and function in the 1946 British birth cohort

2020 ◽  
Author(s):  
Constantin-Cristian Topriceanu ◽  
James C Moon ◽  
Rebecca Hardy ◽  
Nishi Chaturvedi ◽  
Alun Hughes ◽  
...  
Keyword(s):  
Life Course ◽  
Birth Cohort ◽  
Later Life ◽  
Myocardial Contraction ◽  
Left Ventricular ◽  
Heart Size ◽  
Time Periods ◽  
And Function ◽  
The Life Course ◽  
Myocardial Contraction Fraction

Aim: To study the association between the life course accumulation of health deficits and later life heart size and function using data from the 1946 National Survey of Heath and Development (NSHD) British birth cohort, the longest running birth cohort with continuous follow up in the world. Methods and Results: A multidimensional health deficit index (DI) looking at 45 health deficits was serially calculated at 4 time periods of the life course in NSHD participants (0 to 16, 19 to 44, 45 to 54 and 60 to 64 years), and from these the mean and total DI for the life course was derived (DImean, DIsum). The step change in deficit accumulation from one time period to another was also calculated. Echocardiographic data at 60-64 years provided: ejection fraction (EF), left ventricular mass indexed to body surface area (LVmassi, BSA), myocardial contraction fraction indexed to BSA (MCFi) and E/e. Generalized linear models assessed the association between DIs and echocardiographic parameters after adjustment for sex, socioeconomic position and body mass index. 1,375 NSHD participants were included (46.47% male). For each single new deficit accumulated at any one of the 4 time periods of the life course, LVmassi increased by 0.91 to 1.44% (p<0.013), while MCFi decreased by 0.6 to 1.02% (p<0.05 except at 45 to 54 years). One unit increase in DI at age 45 to 54 and 60 to 64 decreased LV EF by 11 to 12% (p<0.013). A single deficit step change occurring between 60-64 years and one of the earlier time periods, translated into significantly higher odds (2.1 to 78.5, p<0.020) of elevated LV filling pressure defined as E/e>13. Conclusion: The accumulation of health deficits at any time period of the life course associates with a maladaptive cardiac phenotype in older age, dominated by myocardial hypertrophy and poorer function. The burden of health deficits appears to strain the myocardium potentially leading to future cardiac dysfunction. Keywords: frailty; cardiovascular disease; ejection fraction; left ventricular mass index; myocardial contraction fraction; E/e.

scholarly journals Performance Analysis and Visualization of Canard and Fuselage Effects on Flow Patterns around a Straight-Body-Type-Fuselage (SBTF) Fighter Models with Experimental Method in Water Tunnel

2018 ◽  
Vol 12 (10) ◽  
pp. 195 ◽  
Author(s):  
Sutrisno . ◽  
Firdaus RS ◽  
Zainuri A ◽  
Sigit Iswahyudi ◽  
Setyawan Bekti Wibowo
Keyword(s):  
Performance Analysis ◽  
Experimental Method ◽  
Vortex Dynamics ◽  
Aerodynamic Force ◽  
Flow Patterns ◽  
Scale Model ◽  
Water Tunnel ◽  
Body Type ◽  
Mixture Ratio ◽  
And Function

Performance analysis and visualization of canard and fuselage effects on flow patterns around an SBTF fighter model have been conducted. An SBTF fighter model with an experimental method in a water tunnel would easily reveal visually the vortex dynamics phenomenon that occurred. Testing has been done, with some form of non-canard and canard aircraft in a water tunnel, on vortex dynamics and aerodynamic power on the aircraft model. The stream demonstration used a fluid speed of 0.1 m/s and Reynolds number 6.577x103 on a 1:110 scale model and measured using dye injection method with a print ink type with a mixture ratio of 1:8. The result of the research using GAMA water tunnel showed the aerodynamic force and vortex dynamics phenomenon that happened on the model aircraft. The research on the benefits of the canard is also done by examining the performance and the flow visualization of an SBTF fighter without fuselage, with the symmetrical plane and with the regular fuselage in a water tunnel. The results showed that the use of canard affected the lift, drag, and flow pattern around the wings. The use of canard can enhance the lift of the plane and function to delay the stall by restoring the flow above the wing which should have experienced turbulence back into laminar so that the fighter can maneuver to a higher angle of attack (AoA) without stalling. It is identified that canard and fuselage play significant roles on the design of a fighter. The design choice of the fuselage and the employment of canard are fundamental to support the ability of maneuver and agility of the fighter.

Actuation of Model Phalanges by Ion Polymer Metal Compound

2012 ◽  
Vol 79 ◽  
pp. 69-74
Author(s):  
Tadashi Ihara ◽  
Taro Nakamura ◽  
Kinji Asaka
Keyword(s):  
Artificial Muscle ◽  
Fast Response ◽  
Metal Compound ◽  
Opening Angle ◽  
Prototype Model ◽  
Small Force ◽  
Polymer Metal ◽  
Function Generators ◽  
And Function ◽  
Contraction And Expansion

We have fabricated a prototype model artificial muscle that drives model phalanges in water with ion polymer metal compound (IPMC) which generates relatively large displacement with fast response but generates relatively small force. We have developed IPMC of greater thickness of up to 600 µm than conventional Nafion 117 based IPMC of 200 µm which enabled to generate greater force. In fabricating IPMC Nafion R-1100 resin was heat-pressed at 185 °C with 20-30 MPa. The thickness of IPMC could be adjusted by changing the amount of resin, pressure, and time to heat-press. Fabricated IPMC was then cut in shapes and an electrode was attached on the surface of IPMC. The device was used as an artificial muscle type actuator which was fabricated in a shape that bridges two conjoining bones, and controls opening angle of the bones that mimics contraction and expansion motion of the muscle. Bipolar power supply and function generators were used to drive IPMC membranes attached to the model phalanges.

scholarly journals Exploring the Relationship between Forest Structure and Health

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1264
Author(s):  
Jinki Kim ◽  
Duk-Byeong Park ◽  
Jung Il Seo
Keyword(s):  
Mental Health ◽  
Physical Activity ◽  
Landscape Metrics ◽  
Forest Structure ◽  
Normal Growth ◽  
Urban Neighborhood ◽  
Forest Patches ◽  
Forest Patch ◽  
Irregular Shapes ◽  
And Function

There is abundant evidence that green space in urban neighborhood is associated with physical activity and it is well known that physical activity contributes to human health. Physical activity fosters normal growth and development, can reduce the risk of chronic diseases, and can make people feel better and function better. Evidences also show that exposure to natural places can lead to positive mental health outcomes, whether a view of nature from a window, being within natural places, or exercising in these environments. The study aims to identify the factors of forest structure and socioeconomic characteristics influencing adults’ physical activity and health. A sample of 148,754 respondents from the Korea Community Health Survey, conducted in 2016, was analyzed. Measures included frequency of physical activity, stress, depression, and landscape metrics of forest patch. Hierarchical multiple regression analysis, controlling for socio-demographic characteristics, revealed that larger forest patches and the more irregular shapes were associated with more physical activity. The study also showed that the shape of forest patch and slope were associated with less mental health complaints, whereas composition related landscape metrics were not.

scholarly journals Myosin Heavy Chains IIa and IId Are Functionally Distinct in the Mouse

1998 ◽  
Vol 141 (4) ◽  
pp. 943-953 ◽  
Author(s):  
Carol A. Sartorius ◽  
Brian D. Lu ◽  
Leslie Acakpo-Satchivi ◽  
Renee P. Jacobsen ◽  
William C. Byrnes ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid Level ◽  
Spinal Curvature ◽  
Developmental Expression ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Fast Myosin Heavy Chain ◽  
Fiber Number ◽  
Murine Skeletal Muscle ◽  
And Function

Myosin in adult murine skeletal muscle is composed primarily of three adult fast myosin heavy chain (MyHC) isoforms. These isoforms, MyHC-IIa, -IId, and -IIb, are &gt;93% identical at the amino acid level and are broadly expressed in numerous muscles, and their genes are tightly linked. Mice with a null mutation in the MyHC-IId gene have phenotypes that include growth inhibition, muscle weakness, histological abnormalities, kyphosis (spinal curvature), and aberrant kinetics of muscle contraction and relaxation. Despite the lack of MyHC-IId, IId null mice have normal amounts of myosin in their muscles because of compensation by the MyHC-IIa gene. In each muscle examined from IId null mice, there was an increase in MyHC-IIa– containing fibers. MyHC-IIb content was unaffected in all muscles except the masseter, where its expression was extinguished in the IId null mice. Cross-sectional fiber areas, total muscle cross-sectional area, and total fiber number were affected in ways particular to each muscle. Developmental expression of adult MyHC genes remained unchanged in IId null mice. Despite this universal compensation of MyHC-IIa expression, IId null mice have severe phenotypes. We conclude that despite the similarity in sequence, MyHC-IIa and -IId have unique roles in the development and function of skeletal muscle.

scholarly journals Normal Lymphatic Development and Function in Mice Deficient for the Lymphatic Hyaluronan Receptor LYVE-1

2006 ◽  
Vol 27 (2) ◽  
pp. 595-604 ◽  
Author(s):  
Nicholas W. Gale ◽  
Remko Prevo ◽  
Jorge Espinosa ◽  
David J. Ferguson ◽  
Melissa G. Dominguez ◽  
...  
Keyword(s):  
Lymphatic Vessels ◽  
Physiological Role ◽  
Normal Growth ◽  
Skin Inflammation ◽  
Lewis Lung ◽  
Lymphatic Development ◽  
Lymph Node Sinus ◽  
And Function ◽  
Draining Lymph Nodes ◽  
Hyaluronan Receptor

ABSTRACT The hyaluronan receptor LYVE-1 is expressed abundantly on the surfaces of lymphatic vessels and lymph node sinus endothelial cells from early development, where it has been suggested to function both in cell adhesion/transmigration and as a scavenger for hyaluronan turnover. To investigate the physiological role(s) of LYVE-1, we generated mice in which the gene for the receptor was inactivated by replacement with a β-galactosidase reporter. LYVE-1−/− mice displayed an apparently normal phenotype, with no obvious alteration in lymphatic vessel ultrastructure or function and no apparent change in secondary lymphoid tissue structure or cellularity. In addition, the levels of hyaluronan in tissue and blood were unchanged. LYVE-1−/− mice also displayed normal trafficking of cutaneous CD11c+ dendritic cells to draining lymph nodes via afferent lymphatics and normal resolution of oxazolone-induced skin inflammation. Finally, LYVE-1−/− mice supported normal growth of transplanted B16F10 melanomas and Lewis lung carcinomas. These results indicate that LYVE-1 is not obligatory for normal lymphatic development and function and suggest either the existence of compensatory receptors or a role more specific than that previously envisaged.

scholarly journals Automatic and unbiased segmentation and quantification of myofibers in skeletal muscle

2021 ◽  
Author(s):  
Ariel Waisman ◽  
Alessandra Norris ◽  
Martín Elías Costa ◽  
Daniel Kopinke
Keyword(s):  
Skeletal Muscle ◽  
Primary Cilia ◽  
Learning Algorithm ◽  
Fixed Tissue ◽  
Deep Learning Algorithm ◽  
Ability To Regenerate ◽  
Murine Skeletal Muscle ◽  
And Function ◽  
Injury Models ◽  
Imagej Plugin

ABSTRACTSkeletal muscle has the remarkable ability to regenerate. However, with age and disease muscle strength and function decline. Myofiber size, which is affected by injury and disease, is a critical measurement to assess muscle health. Here, we test and apply Cellpose, a recently developed deep learning algorithm, to automatically segment myofibers within murine skeletal muscle. We first show that tissue fixation is necessary to preserve cellular structures such as primary cilia, small cellular antennae, and adipocyte lipid droplets. However, fixation generates heterogeneous myofiber labeling, which impedes intensity-based segmentation. We demonstrate that Cellpose efficiently delineates thousands of individual myofibers outlined by a variety of markers, even within fixed tissue with highly uneven myofiber staining. We created a novel ImageJ plugin (LabelsToRois) that allows processing multiple Cellpose segmentation images in batch. The plugin also contains a semi-automatic erosion function to correct for the area bias introduced by the different stainings, identifying myofibers as accurately as human experts. We successfully applied our segmentation pipeline to uncover myofiber size differences between two different muscle injury models, cardiotoxin and glycerol. Thus, Cellpose combined with LabelsToRois allows for fast, unbiased, and reproducible myofiber quantification for a variety of staining and fixation conditions.

Diet according to Symbiosis

1925 ◽  
Vol 71 (292) ◽  
pp. 100-109
Author(s):  
H. Reinheimer
Keyword(s):  
Mode Of Action ◽  
Normal Growth ◽  
Plant Kingdom ◽  
Organic Evolution ◽  
Living Things ◽  
Mutual Adaptation ◽  
Important Sense ◽  
And Function ◽  
In Virtue Of ◽  
Chemical Messengers

According to the late Sir William Bayliss, a leading physiologist, the vitamins, which the plant alone knows how to manufacture, are a kind of chemical messengers (hormones). “They are obtained from the plant, and are particularly abundant in fresh green vegetables and fruit.” … “Their precise mode of action is still unknown, but in their absence normal growth and function is impossible and certain diseases make their appearance.” Hence the normal growth of the animals depends upon stimulations and influences directly derived from the plant kingdom. The evolution of the animal is in large part directed by the plant, which is also saying that it is cosmically directed, in virtue of those terrestrial and solar influences which the plant purveys. But it is also saying, in a most important sense, that all organic evolution is directed by the amount of mutuality existing between the kingdoms and what this involves in bio-sociality. If the vitamins are, in Sir William's words, “obviously a kind of chemical messengers,” then we must consider them as the hormones of symbiosis, as “messengers” of health—the diametric opposites of the alkaloids, the vegetable poisons which are of appalling efficacy in the physiological economy of the animal. By symbiosis I mean not parasitism, not commensalism, but definite, almost deliberate, mutual adaptation for the purpose of mutual service, on the part of living things, nearly always of different orders of creation, broadly, that is, between the plant and the animal (“Norm-symbiosis”).

scholarly journals Biology and Function of miR159 in Plants

Plants ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 255 ◽  
Author(s):  
Anthony A. Millar ◽  
Allan Lohe ◽  
Gigi Wong
Keyword(s):  
Binding Sites ◽  
Growth And Development ◽  
Current Knowledge ◽  
Normal Growth ◽  
Land Plants ◽  
Major Function ◽  
Vegetative Tissues ◽  
Inhibition Of Growth ◽  
And Function ◽  
R2r3 Myb

MicroR159 (miR159) is ancient, being present in the majority of land plants where it targets a class of regulatory genes called GAMYB or GAMYB-like via highly conserved miR159-binding sites. These GAMYB genes encode R2R3 MYB domain transcription factors that transduce the gibberellin (GA) signal in the seed aleurone and the anther tapetum. Here, GAMYB plays a conserved role in promoting the programmed cell death of these tissues, where miR159 function appears weak. By contrast, GAMYB is not involved in GA-signaling in vegetative tissues, but rather its expression is deleterious, leading to the inhibition of growth and development. Here, the major function of miR159 is to mediate strong silencing of GAMYB to enable normal growth. Highlighting this requirement of strong silencing are conserved RNA secondary structures associated with the miR159-binding site in GAMYB mRNA that promotes miR159-mediated repression. Although the miR159-GAMYB pathway in vegetative tissues has been implicated in a number of different functions, presently no conserved role for this pathway has emerged. We will review the current knowledge of the different proposed functions of miR159, and how this ancient pathway has been used as a model to help form our understanding of miRNA biology in plants.

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