Mechanical Response of the Herniated Human Abdomen to the Placement of Different Prostheses

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Belén Hernández-Gascón ◽  
Estefanía Peña ◽  
Jorge Grasa ◽  
Gemma Pascual ◽  
Juan M. Bellón ◽  
...  
Keyword(s):  
Mechanical Response ◽  
The Body ◽  
Abdominal Pressure ◽  
Anatomical Structures ◽  
Surgical Meshes ◽  
Real Geometry ◽  
Static Mechanical ◽  
Physiological Movement ◽  
Light Weight Mesh ◽  
Medium Weight

This paper describes a method designed to model the repaired herniated human abdomen just after surgery and examine its static mechanical response to the maximum intra-abdominal pressure provoked by a physiological movement (standing cough). The model is based on the real geometry of the human abdomen bearing a large incisional hernia with several anatomical structures differentiated by MRI. To analyze the outcome of hernia repair, the surgical procedure was simulated by modeling a prosthesis placed over the hernia. Three surgical meshes with different mechanical properties were considered: an isotropic heavy-weight mesh (Surgipro®), a slightly anisotropic light-weight mesh (Optilene®), and a highly anisotropic medium-weight mesh (Infinit®). Our findings confirm that anisotropic implants need to be positioned such that the most compliant axis of the mesh coincides with the craneo-caudal direction of the body.

scholarly journals Mathematical Modeling and Numerical Simulation of Atherosclerosis Based on a Novel Surgeon’s View

2021 ◽  
Author(s):  
Meisam Soleimani ◽  
Axel Haverich ◽  
Peter Wriggers
Keyword(s):  
Mathematical Modeling ◽  
Inflammatory Response ◽  
Phase Field ◽  
Mechanical Response ◽  
Type Equation ◽  
The Body ◽  
Vasa Vasorum ◽  
Diffusion Reaction ◽  
Dust Particles ◽  
Driving Mechanism

AbstractThis paper deals with the mathematical modeling of atherosclerosis based on a novel hypothesis proposed by a surgeon, Prof. Dr. Axel Haverich (Circulation 135(3):205–207, 2017). Atherosclerosis is referred as the thickening of the artery walls. Currently, there are two schools of thoughts for explaining the root of such phenomenon: thickening due to substance deposition and thickening as a result of inflammatory overgrowth. The hypothesis favored here is the second paradigm stating that the atherosclerosis is nothing else than the inflammatory response of of the wall tissues as a result of disruption in wall nourishment. It is known that a network of capillaries called vasa vasorum (VV) accounts for the nourishment of the wall in addition to the natural diffusion of nutrient from the blood passing through the lumen. Disruption of nutrient flow to the wall tissues may take place due to the occlusion of vasa vasorums with viruses, bacteria and very fine dust particles such as air pollutants referred to as PM 2.5. They can enter the body through the respiratory system at the first place and then reach the circulatory system. Hence in the new hypothesis, the root of atherosclerotic vessel is perceived as the malfunction of microvessels that nourish the vessel. A large number of clinical observation support this hypothesis. Recently and highly related to this work, and after the COVID-19 pandemic, one of the most prevalent disease in the lungs are attributed to the atherosclerotic pulmonary arteries, see Boyle and Haverich (Eur J Cardio Thorac Surg 58(6):1109–1110, 2020). In this work, a general framework is developed based on a multiphysics mathematical model to capture the wall deformation, nutrient availability and the inflammatory response. For the mechanical response an anisotropic constitutive relation is invoked in order to account for the presence of collagen fibers in the artery wall. A diffusion–reaction equation governs the transport of the nutrient within the wall. The inflammation (overgrowth) is described using a phase-field type equation with a double well potential which captures a sharp interface between two regions of the tissues, namely the healthy and the overgrowing part. The kinematics of the growth is treated by classical multiplicative decomposition of the gradient deformation. The inflammation is represented by means of a phase-field variable. A novel driving mechanism for the phase field is proposed for modeling the progression of the pathology. The model is 3D and fully based on the continuum description of the problem. The numerical implementation is carried out using FEM. Predictions of the model are compared with the clinical observations. The versatility and applicability of the model and the numerical tool allow.

Numerical Analysis of Branch Mechanical Response to Loading

2019 ◽  
Vol 45 (4) ◽  
Author(s):  
Barbora Vojáčková ◽  
Jan Tippner ◽  
Petr Horáček ◽  
Luděk Praus ◽  
Václav Sebera ◽  
...  
Keyword(s):  
Finite Element ◽  
Cross Sections ◽  
Mechanical Response ◽  
Mechanical Analysis ◽  
Beam Deflection ◽  
Design System ◽  
Elliptical Cross ◽  
Static Mechanical ◽  
The Difference ◽  
Tree Uprooting

Failure of a tree can be caused by a stem breakage, tree uprooting, or branch failure. While the pulling test is used for assessing the first two cases, there is no device-supported method to assess branch failure. A combination of the optical technique, pulling test, and deflection curve analysis could provide a device-supported tool for this kind of assessment. The aim of the work was to perform a structural analysis of branch response to static mechanical loading. The analyses were carried out by finite element simulations in ANSYS using beam tapered elements of elliptical cross-sections. The numerical analyses were verified by the pulling test combined with a sophisticated optical assessment of deflection evaluation. The Probabilistic Design System was used to find the parameters that influence branch mechanical response to loading considering the use of cantilever beam deflection for stability analysis. The difference in the branch’s deflection between the simulation and the experiment is 0.5% to 26%. The high variability may be explained by the variable modulus of the elasticity of branches. The finite element (FE) sensitivity analysis showed a higher significance of geometry parameters (diameter, length, tapering, elliptical cross-section) than material properties (elastic moduli). The anchorage rotation was found to be significant, implying that this parameter may affect the outcome in mechanical analysis of branch behavior. The branch anchorage can influence the deflection of the whole branch, which should be considered in stability assessment.

A STUDY ON SROTODUSHTI WITH SPECIAL REFERENCE TO ASSESSMENT OF SROTOSHTI LAKSHANA IN ARTAVAVAHA SROTAS THROUGH CLINICAL, BIOCHEMICAL AND RADIOLOGICAL FINDINGS’- SURVEY STUDY

2021 ◽  
Vol 9 (10) ◽  
pp. 2339-2346
Author(s):  
Shivakumari Shivakumari ◽  
Vasudev A Chate ◽  
Shreevastha Shreevastha
Keyword(s):  
Special Reference ◽  
Transport System ◽  
Normal State ◽  
The Body ◽  
Radiological Examination ◽  
Survey Study ◽  
Radiological Findings ◽  
Anatomical Structures ◽  
Conceptual Study

The concept of Srotas and Srotodushti Lakshana has been very scientifically explained in the various context of Ayurveda literature. Detailed Srotas and Srotodushti Lakshana are according to Charaka Samhita Vimansthana assessment of Srotodushti Lakshana can be done by Pratyksha Pramana and in detail explanation. The Srotas play an important role in physiology and the pathogenesis of diseases in normal state; they regulate the physiolo- gy of the body and maintain the anatomical structures of dhatus. The influences of aetiology factors on Srotas can affect pathological manifestations. Considering this fact present study explores various aspects related to the Sro- tas, Srotodushti and Srotodushti Lakshana. Objectives-To assessment of Srotodushti Lakshana in Artavavaha Srotas through Clinical, biochemical, and radiological examination in Artavavaha Srotas. Methodology -The study was conducted under two headings, conceptual and survey study. Conceptual study all the concerned litera- ture were referred and analysed and for survey study, the Artvavaha Sroto Vikara observed and survey through face-face interview. -Hence it is concluded that the knowledge of Srotas is not only used in learning about the anatomy of the transport system of the body but also to understand their physiology and pathology. It can be as- sessed through clinical, biochemical, and radiological findings. Keywords: Srotas, Srotodushti Lakshana, Artavavaha Srotas,

scholarly journals Results Of Treatment Of Acute Diffuse Purulent Peritonitis Using Laparostomy

2020 ◽  
Vol 02 (11) ◽  
pp. 66-71
Author(s):  
S. A. Ruziboev ◽  
◽  
A. A. Avazov ◽  
Sh. Kh. Sattarov ◽  
A. N. Elmuradov ◽  
...  
Keyword(s):  
Bacterial Translocation ◽  
Abdominal Cavity ◽  
Multiple Organ ◽  
The Body ◽  
Abdominal Pressure ◽  
Results Of Treatment ◽  
Abdominal Hypertension ◽  
Purulent Peritonitis ◽  
Intractable Problems ◽  
Cause Of Deaths

Currently, despite significant achievements in the field of surgery, anesthesiology and resuscitation, the results of treatment of patients with advanced purulent peritonitis remain one of the most intractable problems, almost every sixth patient with acute surgical diseases and injuries of the abdominal cavity is admitted to medical institutions with peritonitis [1,3] Common peritonitis in 17-29% complicates the course of most acute surgical diseases and is the main cause of deaths in surgical hospitals [3,7]. Lethality in advanced peritonitis remains extremely high and reaches 20-39% [1,2,4,5]. In recent decades, great importance has been attached to recording intra-abdominal pressure in purulent pathology of the abdominal cavity. It was found that intra-abdominal hypertension occurs in every third patient with acute surgical pathology and negatively affects the functioning of all organs and systems of the body [1,6,8]. Pathological changes that occur with acute and excessive increase in intra-abdominal pressure (IAP) are manifestations of abdominal compartment syndrome (ACS) with disorders of the cardiovascular system; urinary disorders, disorders of perfusion of internal organs and the development of intestinal ischemia, which contributes to bacterial translocation and endogenous infection [2,7,8]. Ischemic blood flow disorders of the splanchnic zone are fraught with the development of bacterial translocation and the development of systemic inflammatory response syndrome and multiple organ failure (PON). Unsatisfactoriness with such results gave rise to a fundamentally different approach to the surgical treatment of common forms of peritonitis-the introduction of an open abdominal management method based on the ideas of I. Mikulich (1881), Jean-Louis Faure (1928), N. S. Makoch (1984) and D. Steinberg (1979).

Abdominal wall hernias

2018 ◽  
pp. 529-540
Author(s):  
Abdullah Jibawi ◽  
Mohamed Baguneid ◽  
Arnab Bhowmick
Keyword(s):  
Connective Tissue ◽  
Abdominal Wall ◽  
Chronic Cough ◽  
Incidental Finding ◽  
Clinical History ◽  
The Body ◽  
Abdominal Pressure ◽  
Ehlers Danlos Syndrome ◽  
Danlos Syndrome ◽  
Groin Hernias

Hernias are abnormal protrusion of an organ through a weakness/defect in the body wall that contains it. Classifications include groin hernias, ventral abdominal wall hernias (umbilical, femoral), incisional, Spigelian, and lumbar hernias. Inguinal hernias are the commonest types of abdominal wall hernias (~75%). Male are affected 15-times more frequently. Hernias are more common in smokers, patients with underlying connective tissue disorders (Ehlers Danlos Syndrome, Marfan syndrome), and patients with increased intra-abdominal pressure (obesity, heavy lifting, chronic cough, and chronic straining during defecation and urination). Hernias present as incidental finding on imaging, asymptomatic lumps, painful lumps, or incarcerated or strangulated hernias. Clinical history and examination are the mainstay of diagnosis. Most hernias are treated with surgical repair (open or laparoscopic). Conservative wait and watch policy is indicated in some cases.

scholarly journals Mechanical Characterization of Nanocomposite Joints Based on Biomedical Grade Polyethylene under Cyclical Loads

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2681
Author(s):  
Annamaria Visco ◽  
Cristina Scolaro ◽  
Antonino Quattrocchi ◽  
Roberto Montanini
Keyword(s):  
Titanium Dioxide ◽  
Mechanical Response ◽  
Mechanical Characterization ◽  
Laser Light ◽  
Mechanical Tests ◽  
Fatigue Tests ◽  
Weight Content ◽  
Percentage Weight ◽  
Static Mechanical

Polymeric joints, made of biomedical polyethylene (UHMWPE) nanocomposite sheets, were welded with a diode laser. Since polyethylene does not absorb laser light, nanocomposites were prepared containing different percentages by weight of titanium dioxide as it is a laser absorbent. The joints were first analyzed with static mechanical tests to establish the best percentage weight content of filler that had the best mechanical response. Then, the nanocomposites containing 1 wt% titanium dioxide were selected (white color) to be subjected to fatigue tests. The experimental results were also compared with those obtained on UMMWPE with a different laser light absorbent nano filler (carbon, with greater laser absorbing power, gray in color), already studied by our research team. The results showed that the two types of joints had an appreciable resistance to fatigue, depending on the various loads imposed. Therefore, they can be chosen in different applications of UHMWPE, depending on the stresses imposed during their use.

Design and Research on Aluminum-Plastic Trunk Lid

2012 ◽  
Vol 538-541 ◽  
pp. 833-840
Author(s):  
Duo Nian Yu ◽  
Li Yang Gu ◽  
Chong Yang Lu
Keyword(s):  
Design Method ◽  
The Body ◽  
Frame Structure ◽  
Light Weight ◽  
Mechanical Stiffness ◽  
Plastic Structure ◽  
Stiffness Properties ◽  
Body Design ◽  
Static Mechanical ◽  
Panel Thickness

Abstract: In this paper, the traditional trunk lid was analyzed using finite element method firstly, and then the basic mechanical properties of the lid were obtained, which were used as the topology optimization constrains of the trunk lid outer panel, then the aluminum alloy frame structure that could satisfy the static mechanical stiffness properties was designed; According to the requirement, the trunk lid inner panel was redesigned, the material properties determined in advance were given to the inner and outer panel respectively, after being assembled, the best panel thickness could be obtained by ways of size optimization. Compared to the analysis results, the new aluminum-plastic structure can meet the requirements in performance, and has significant effect on light-weight. This paper provides some reference for the development of the aluminum-plastic structure of the body design method.

On thermodynamics and the nature of the second law

1977 ◽  
Vol 357 (1690) ◽  
pp. 253-270 ◽  
Keyword(s):  
Mechanical Response ◽  
The Body ◽  
Temperature Fields ◽  
Second Law ◽  
Fading Memory ◽  
New Approach ◽  
Spatially Homogeneous ◽  
Dissipative Material ◽  
Point Of Departure ◽  
Homogeneous Temperature

The contents of this paper represent a new approach to continuum thermo­dynamics and are chiefly concerned with ( a ) a procedure for obtaining restrictions on constitutive equations, ( b ) an appropriate mathematical statement of the second law and ( c ) the nature of restrictions placed by the latter on thermo-mechanical behaviour of single phase continua. Our point of departure is the introduction of a balance of entropy and the use of the energy equation as an identity for all motions and all temperature distributions after the elimination of the external fields. This is in contrast to the approach adopted in most of the current literature on continuum ther­modynamics based on the use of the Clausius-Duhem inequality. In order to gain some insight into the nature of our procedure we first study the case of an elastic material, which includes that of an ideal fluid as a special case, before the consideration of the second law. We then go on to postu­late an inequality which reflects the fact that for every process associated with a dissipative material, a part of the mechanical work is always con­verted into heat and this cannot be withdrawn from the medium as mech­anical work. The restriction on the heat conduction vector is considered separately and is confined to equilibrium cases in which heat flow is steady. A restriction is also obtained for the internal energy when the body is in mechanical equilibrium subjected to spatially homogeneous temperature fields. Using the above approach, next we study the nature of thermodynamic restrictions on the thermo-mechanical response of a viscous fluid and simple materials with fading memory. A drawback to the Clausius-Duhem inequality is discussed by means of an example. For a class of rigid heat conductors in thermal equilibrium, the Clausius-Duhem inequality requires that if heat is added to the medium, the resulting spatially homogeneous temperature of the conductor decreases . Moreover, the in­-equality denies the possibility of propagation of heat in the conductor as a thermal wave with finite speed. The inequalities proposed in this paper do not suffer from these shortcomings.

On the Stability Analysis of the Human Spine

2003 ◽  
Author(s):  
M. El-Rich ◽  
A. Shirazi-Adl
Keyword(s):  
Stability Analysis ◽  
Material Handling ◽  
Muscle Activation ◽  
The Body ◽  
Abdominal Pressure ◽  
Human Spine ◽  
Manual Material Handling ◽  
The Stability ◽  
Force Relationship

The stability of the human spine in compression has attracted a considerable amount of attention in recent years. The passive ligamentous thoracolumbar and lumbar spines are known to exhibit large displacements or hypermobility (i.e., instability in an imperfect column) under compression loads <100N. Since such compression loads are only a small fraction of those supported by the spine even in regular daily activities, let aside the manual material handling tasks, the question arises as to how the spine is stablized in vivo? Various stabilizing mechanisms have been proposed and investigated; wrapping loading [Shirazi-Adl and Parnianpour, 2000], postural adaptations [Shirazi-Adl and parnianpor, 1999], intra-abdominal pressure [Cholewicki et al, 1999] and muscle activation/coactivation [Bergmark, 1989; Crisco and Panjabi, 1991]. In this work, a novel kinematics-based methad [Shirazi-Adl et al., 2002] is first applied to compute muscle forces and internal loads in standing postures under gravity with or without 200N loads held either on sides or close to the body in front. The stability of the system under given loads and prescribed postures is sudsequently examined using both linear bucking analysis based on the deformed configurations and nonlinear analysis while employing a liner stiffness-force relationship for muscules [Bergmark, 1989; Crico and Panjabi, 1991]. The relative accuracy of foregoing methods in stability analysis of some sample structures is also investigated. Moreover, the effect of co-activity on stability of the spine in neutral postures is studied.

scholarly journals Design and Demonstration of a Microbiaxial Optomechanical Device for Multiscale Characterization of Soft Biological Tissues with Two-Photon Microscopy

2011 ◽  
Vol 17 (2) ◽  
pp. 167-175 ◽  
Author(s):  
Joseph T. Keyes ◽  
Stacy M. Borowicz ◽  
Jacob H. Rader ◽  
Urs Utzinger ◽  
Mohamad Azhar ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Tissue Sample ◽  
Imaging Techniques ◽  
High Stress ◽  
Viscoelastic Behavior ◽  
Biological Tissues ◽  
The Body ◽  
Two Photon ◽  
Biomechanical Response ◽  
Tissue Specimens

AbstractThe biomechanical response of tissues serves as a valuable marker in the prediction of disease and in understanding the related behavior of the body under various disease and age states. Alterations in the macroscopic biomechanical response of diseased tissues are well documented; however, a thorough understanding of the microstructural events that lead to these changes is poorly understood. In this article we introduce a novel microbiaxial optomechanical device that allows two-photon imaging techniques to be coupled with macromechanical stimulation in hydrated planar tissue specimens. This allows that the mechanical response of the microstructure can be quantified and related to the macroscopic response of the same tissue sample. This occurs without the need to fix tissue in strain states that could introduce a change in the microstructural configuration. We demonstrate the passive realignment of fibrous proteins under various types of loading, which demonstrates the ability of tissue microstructure to reinforce itself in periods of high stress. In addition, the collagen and elastin response of tissue during viscoelastic behavior is reported showing interstitial fluid movement and fiber realignment potentially responsible for the temporal behavior. We also demonstrate that nonhomogeneities in fiber strain exist over biaxial regions of assumed homogeneity.

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