Aug 152018

Tissue under loading

Objective 1

From the project requirement, we are aware that the various parameters needed to calculate the theoretical stress and displacement.

The formula being used is:

The x values used here are 0 on the left side of the beam and 0 again on the right end of the beam. This is so that the maximum displacement can be at the bottom of the beam. When the load acts on the beam, it looks like this figure 1.

Figure 1: Y displacement on FEM

Apr 222018

Cell Mechanics

The two papers I am reviewing are “Biomechanics: Cell Research and Application for the Next Decade” by Dennis Discher et al. at University of Pennsylvania and “Experimental techniques for single cell and single molecule biomechanics” by C.T. Lim et al at National University of Singapore. Both the papers have their own approach of looking at the field of biomechanics in the context of cell structure and its function but both of them highlight the various possibilities in cell biomechanics and what the future holds for the researchers to currently focus on. The first paper explores the various accomplishments that have already been made in the field and what are some other developments and challenges that we can look forward to in the coming decades. The second paper highlights the importance of research in the field of cell mechanics and how to test various mechanical properties. Lim, in detail, explains three experimental techniques, and how he has used those techniques in the lab, and also how other researches are planning to use the particular experimental technique.

Cells make each and every component of our body, and therefore, are immensely complicated. Understanding the processes that take place in the cells can considerably expand our understanding about the human body. This can further help us create diagnosis techniques, drugs or preventative methods of handling the various diseases. As pointed out in the papers, these conditions are greatly in relation to the mechanics that takes place inside the cell. This is due to the constant stresses and strains acting on these cells and it turns out that these parameters greatly affect the mechanisms taking place inside the cells. An understanding not just at the cellular level, but also molecular level is required to fully comprehend the various functionalities of the cells. To provide an example, in cells that have malaria, as the disease progresses into worse conditions, various differences in mechanical and viscoelastic properties are observed.

Mar 122018

Bone Mechanics

The two papers I am reviewing are – “Biomechanical behaviour of muscle-tendon complex during dynamic human movement” – Senshi Fukashiro, Dean C. Day and Akinori Nagano, and “Passive properties of human skeletal muscle during stretch maneuvers” – S. P. Magnusson. The muscle tendon complex and human skeletal muscle are synonymous. These are the muscles that help us create dynamic movements, which includes – jumping, stretching, heel raise exercise. The second article is published in Journal of Medicine and Science in Sports, which speaks for itself that such studies are greatly beneficial for understanding the long term fatigue of the muscle-tendon system. Also, it is essential to discover the various mechanical properties along with the benefits of stretching exercises for the athletes. Such research papers are heavily based on experimental work and can take months for data collection and data analysis. It is hard to recreate the same conditions for each experiment as the specimen (animal or human) cannot be controlled. However, authors have tried to perform some repeated controlled experiments also that will be discusses later. Several experiments have also been done to compare the muscle conditions for youngsters and older people. The study the authors are conducting is based on a 1970 study done where it was suggested that muscoskeletal tightness might be related to the muscle strain, while the loose joints had a higher chance of ligament injury. This idea of flexibility and injury due to its absence (in some essence) is the key basis of these two papers. It is believed that this increased risk of injury can be explained by material properties of the muscles.

Feb 262018

Tissue Mechanics

The main function of the heart is the unidirectional flow of blood throughout the body. This is the same organ that beats upto 3 billion times. The blood is estimated to travel at 1.35±0.35 m/s. This is 3 miles per hour. Each time, the blood pumps from anywhere between 3-5L of blood in every cycle. Human body is truly remarkable. In one of our classes, we are looking at a fatigue analysis of a lug stud of a car wheel and we consider an infinite life with 1 million cycles in the context of material analysis. A heart goes through an even greater number of cycles, and therefore, more theoretical and practical knowledge of mechanical properties of heart valves and tissues is required in order to comprehend and treat the numerous heart related diseases.

To provide a little bit of motivation for towards the field of tissue engineered heart valves, numerous diseases are related to a not comprehensive understanding of our heart or a shortage of available products in the market for tissue transplant. Every year, 290,000 patients go through valve replacement surgeries worldwide, and this number is projected to increase to 850,000 by 2050. The reason these have to be replaced is because a large number of valves cannot be repaired. Since heart is a delicate organ, extracting and valve, treating it and then placing it back is a time consuming process and this risk, doctors are not willing to take. This is why there is a huge role for the field of Biomechanics to play in this heart valve tissue knowledge gap. About 110,000 people die every year due to valvular heart diseases in the United States and this is an urgent field of study that needs to be addressed.

Feb 052018

Brain Mechanics

The brain is one of the most critical organs of the body. Being the most critical, it is also one of the most complex organs. This is because of the vastness in scales – extremely soft scale associated with neurosurgery; extremely hard scale associated with skill; extremely slow scale associated with brain development and the extremely fast scale with neuron communications. In brain, there are 86 billion neurons with 100 trillion connections. These numbers are beyond our comprehension and through the area of biomechanics, we try to explain some of them. Yearly, 160 billion Euros are spent in European Union alone on brain traumatic diseases. This provides an obvious motivation to delve into neuroscience and expand the field in areas where we can understand the brain better.

A part of neuroscience that is rising is neuromechanics and comparatively, much less is known in this field of study. Many major brain development, brain mechanisms, and diseases are correlated with their mechanical response of the brain both at the cellular and tissue levels. Jumping into this field is a jump into diving into something new as much of the research conducted is either relatively new or there are numerous knowledge gaps to fill up. An anatomical components of the brain is available in terms of geometry and 3D modelling due to an advancement in computation, however, knowledge in the area of mechanical behaviour of brain tissue is lacking. Computation is important in every engineering field in today’s day and age and it’s the same in brain mechanics, a comprehensive 3D and a finite element model of a brain would largely enhance our capability to understand what this complex human organs consists of. This is challenge in every field of science – model building.

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