scholarly journals A quantitative high resolution computational cell model to unravel the mechanics in living tissues

2019 ◽  
Vol 22 (sup1) ◽  
pp. S367-S369
Author(s):  
P. Van Liedekerke ◽  
J. Neitsch ◽  
T. Johann ◽  
E. Warmt ◽  
I. Gonzalez-Valverde ◽  
...  
Keyword(s):  
High Resolution ◽  
Cell Model ◽  
Computational Cell ◽  
Living Tissues

A Failure Assessment Procedure for Cracked Pipelines Incorporating a Damage Criterion for Crack Growth

2004 ◽  
Author(s):  
Fernando Dotta ◽  
Eduardo Hippert ◽  
Claudio Ruggieri
Keyword(s):  
Crack Growth ◽  
Crack Extension ◽  
Cell Model ◽  
Pipeline Steel ◽  
Longitudinal Crack ◽  
High Strength ◽  
Experimental Program ◽  
Assessment Procedure ◽  
Ductile Crack ◽  
Computational Cell

This study extends a micromechanics approach based upon the computational cell methodology to model ductile crack extension of longitudinal crack-like defects in a high strength pipeline steel. Laboratory testing of an API 5L X60 AND x70 pipeline steel at room temperature using standard, deep crack C(T) specimens provide the data needed to measure the crack growth resistance curve for the material. In the computational cell model, ductile crack extension occurs through void growth and coalescence (by cell extinction) within a thin layer of material ahead of crack tip. A simple scheme to calibrate material-specific parameters for the cells is also described. A central focus of the paper is the application of the cell methodology to predict experimentally measured burst pressures for pre-cracked pipe specimens with different crack sizes. The experimental program includes longitudinally precracked pipe specimens with 8 5/8” (209 mm) and 20” (508 mm) O.D. The numerical simulations demonstrate the effectiveness of the cell approach to describe crack growth response and to predict the burst pressure for the tested pipes.

An Ear-Tissue Model for High-Resolution In Vivo Imaging.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1456-1456
Author(s):  
Yiqun Jiao ◽  
Ping Zhang ◽  
Divino DeOliveira ◽  
Nicholas Drago ◽  
Nelson J. Chao ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Bone Marrow ◽  
T Cell ◽  
High Resolution ◽  
Real Time ◽  
Nude Mice ◽  
Thymic Tissue ◽  
Mouse Ear ◽  
Living Tissues ◽  
And Function

Abstract Abstract 1456 The use of microscopy in medicine has revolutionized medical research, diagnosis, and treatment. Unfortunately, current use of microscopy is mostly limited to 2 dimensional structures. The introduction of next generation microscopy, such as confocal and multiphoton, has enabled study of 3 dimensional structures deep in living tissues. Because there is a limit as to how deep these microscopic techniques can detect signal in tissue, many tissues/organs can not be studied due to inaccessibility (e.g., thymus). We have been using an ear-heart murine model to study immune tolerance. In this model, a heart from a newborn mouse is transplanted subcutaneously into the ear pinna. If the heart is not rejected (e.g., syngeneic setting), it can survive and beat indefinitely. In this study, we tested a hypothesis that other tissues can also be transplanted into the mouse ear pinna and function. Skin on the mouse ear pinna is extremely thin (<15 μm), thus allowing for visualization of cellular and subcellular changes in transplanted tissues in 4 dimensions (3D plus time) in real time using existing technologies such as multiphoton microscopy. We transplanted a variety of C57BL/6 adult (lung, trachea, aorta, kidney, bone marrow, thymus, spleen, lymph node, skeletal muscle, thyroid gland, adrenal gland) and fetal (colon, ileum, stomach, heart, lung, kidney, bone marrow, thymus, spleen, skeletal muscle) tissues subcutaneously into syngeneic mouse ear pinna. All of these tissues were able to survive at least 4–8 weeks after transplantation. Many of these tissues maintained normal or close to normal structures for at least 4–8 weeks. We chose an ear-thymus model to test whether the engrafted tissues can function. Thymic tissue from C57BL/6 newborn mice (<48 hrs) was transplanted into BALB/c nude mice (lacking thymic tissue). The numbers of CD4+ and CD8+ T cells were followed by flow cytometric analysis in peripheral blood over time. CD4+ T cell counts were significantly higher in thymic tissue recipients compared with sham transplanted control group (Figure, P<0.05). As an internal control, B220+ B cells, which are normal in nude mice and are not produced in thymus, remained similar between transplanted and sham transplanted groups at all time points. To test whether this model is useful for high-resolution imaging in live animals, we transplanted GFP+ C57BL/6 T cell depleted bone marrow into thymic tissue recipients. After bone marrow transplantation, almost all hematopoietic cells were replaced by GFP+ cells. Using two photon microscopy technology, we were able to obtain 4 dimension images of the transplanted thymic tissue at the cellular level in living animals. Because surgical exposure is not required, we were able to perform imaging of living tissues repeatedly in these animals indefinitely. We conclude that multiple tissues are able to survive and function for a long period of time when transplanted into ear pinna. Our innovative ear-tissue transplant model has the potential to allow many living tissues to be visualized at the cellular and subcelluar level in real time and in live animals. Disclosures: Chao: Genzyme: Research Funding.

Burst Pressure Predictions of Cracked Pipelines Using a Micromechanics Approach

2003 ◽  
Author(s):  
Fernando Dotta ◽  
Claudio Ruggieri
Keyword(s):  
Crack Growth ◽  
Crack Extension ◽  
Cell Model ◽  
Pipeline Steel ◽  
Longitudinal Crack ◽  
Experimental Program ◽  
Burst Pressure ◽  
Internal Crack ◽  
Ductile Crack ◽  
Computational Cell

This study extends a micromechanics approach based upon the computational cell methodology to model ductile crack extension of longitudinal crack-like defects in a high strength pipeline steel. Laboratory testing of an API 5L X60 steel at room temperature using standard, deep crack C(T) specimens provide the data needed to measure the crack growth resistance curve for the material. In the computational cell model, ductile crack extension occurs through void growth and coalescence (by cell extinction) within a thin layer of material ahead of crack tip. A simple scheme to calibrate material-specific parameters for the cells is also described. A central focus of the paper is the application of the cell methodology to predict experimentally measured burst pressures for pre-cracked pipe specimens with different crack sizes. The experimental program includes longitudinally precracked 20” (508 mm) O.D. pipe specimens with 15.8 mm thickness containing an internal crack with notch depth (a) and notch length (2c) 7 × 140 mm. Large-scale, full 3-D computations are conducted on detailed finite element models for the pipe specimens to describe crack extension with increased pressure. The numerical simulations demonstrate the effectiveness of the cell approach to describe crack growth response and to predict the burst pressure for the tested pipes.

scholarly journals A quantitative high-resolution computational mechanics cell model for growing and regenerating tissues

2019 ◽  
Vol 19 (1) ◽  
pp. 189-220 ◽  
Author(s):  
Paul Van Liedekerke ◽  
Johannes Neitsch ◽  
Tim Johann ◽  
Enrico Warmt ◽  
Ismael Gonzàlez-Valverde ◽  
...  
Keyword(s):  
High Resolution ◽  
Blood Vessels ◽  
Cell Model ◽  
Medical Decision ◽  
Drug Induced ◽  
Tissue Organization ◽  
A Cell ◽  
Mechanical Elements ◽  
Scalable Network ◽  
The Impact

AbstractMathematical models are increasingly designed to guide experiments in biology, biotechnology, as well as to assist in medical decision making. They are in particular important to understand emergent collective cell behavior. For this purpose, the models, despite still abstractions of reality, need to be quantitative in all aspects relevant for the question of interest. This paper considers as showcase example the regeneration of liver after drug-induced depletion of hepatocytes, in which the surviving and dividing hepatocytes must squeeze in between the blood vessels of a network to refill the emerged lesions. Here, the cells’ response to mechanical stress might significantly impact the regeneration process. We present a 3D high-resolution cell-based model integrating information from measurements in order to obtain a refined and quantitative understanding of the impact of cell-biomechanical effects on the closure of drug-induced lesions in liver. Our model represents each cell individually and is constructed by a discrete, physically scalable network of viscoelastic elements, capable of mimicking realistic cell deformation and supplying information at subcellular scales. The cells have the capability to migrate, grow, and divide, and the nature and parameters of their mechanical elements can be inferred from comparisons with optical stretcher experiments. Due to triangulation of the cell surface, interactions of cells with arbitrarily shaped (triangulated) structures such as blood vessels can be captured naturally. Comparing our simulations with those of so-called center-based models, in which cells have a largely rigid shape and forces are exerted between cell centers, we find that the migration forces a cell needs to exert on its environment to close a tissue lesion, is much smaller than predicted by center-based models. To stress generality of the approach, the liver simulations were complemented by monolayer and multicellular spheroid growth simulations. In summary, our model can give quantitative insight in many tissue organization processes, permits hypothesis testing in silico, and guide experiments in situations in which cell mechanics is considered important.

Structural Integrity Assessments of Pipelines Using Crack Growth Resistance Curves

2002 ◽  
Author(s):  
Eduardo Hippert ◽  
Fernando Dotta ◽  
Claudio Ruggieri
Keyword(s):  
Crack Growth ◽  
Structural Integrity ◽  
Cell Model ◽  
Crack Depth ◽  
High Strength ◽  
Crack Growth Resistance ◽  
Burst Pressure ◽  
Computational Cell ◽  
Cell Parameters ◽  
Thin Walled

This study explores further extension of the computational cell methodology to model Mode I crack extension in high strength pipeline and structural steels. First, validation analyses of the cell methodology described in this study compare predictions of crack growth response with experimentally measured R-curves for a standard DIN StE 460 steel. Next, laboratory testing of an API 5L X70 steel at room temperature using standard, deep crack C(T) specimens provides the crack growth resistance curve to calibrate the micromechanics cell parameters for the material. The cell model incorporating the calibrated material-specific parameters is then applied to predict the burst pressure of a thin-walled gas pipeline containing longitudinal cracks with varying crack depth to thickness ratios (a/t). The plane-strain analyses reported here demonstrate the capability of the computational cell approach to simulate ductile crack growth and to predict the burst pressure of thin-walled tubular structures containing crack-like defects.

scholarly journals Terahertz Imaging Patch Antenna for Cancer Diagnosis Applications

2020 ◽  
Vol 9 (3) ◽  
pp. 3258-3261
Keyword(s):  
High Resolution ◽  
Microstrip Antenna ◽  
Low Cost ◽  
Terahertz Imaging ◽  
Simulation Tool ◽  
Microscopic Imaging ◽  
X Ray ◽  
Cancer Breast ◽  
The World ◽  
Living Tissues

Cancer is the world second most common syndrome which causes death. In statistics nearly one of every four death occurs day-to-day, but it is remediable if detected earlier. The numerous imaging technologies exist for diagnosis with different constrains but those techniques provide either macroscopic or microscopic imaging. Histopathology of biopsy samples uses microscopic imaging methods to provide corporeal and functional information. In macroscopic level X-ray and MRI are used to provide images of living tissues and can achieve only much poorer resolution and specificity. Moreover it is harmful in terms of radiation and other causes To syndicate the macroscopic and microscopic imaging progresses, for delineating the precise margins of cancers is one of the prime mysterious complication in medical imaging.The THztomography research does that syndication and achieves much high resolution with Non-ionizing radiation. The proposed nanomaterial based Microstrip antenna is pertinent to do THztomography with low cost and high resolution which can diagnosis and detection various cancers such as skin cancer, breast cancer, cervical cancer and colon cancer. In this paper, a terahertz imaging antenna was designed and analyzed using Ansys - HFSS v.14 simulation tool.

Sign in / Sign up

Export Citation Format

Share Document