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Full-Text Articles in Mechanical Engineering

Bacteria Movement Near Surfaces, Shulin Wang, Adib Ahmadzadegan, Arezoo Ardekani Aug 2018

Bacteria Movement Near Surfaces, Shulin Wang, Adib Ahmadzadegan, Arezoo Ardekani

The Summer Undergraduate Research Fellowship (SURF) Symposium

Understanding the behaviors of bacteria near surfaces is crucial in many biological and ecological applications. This knowledge can be used to hinder undesired biofilm formation on medical instruments and wounds. On top of that, it could also provide further insights in biodegradation of dispersed oil. In this work, the behavior of Escherichia Coli near a surface was experimentally studied. We utilized an inverted microscope in the phase filed illumination mode and processed acquired images to track the motions of bacteria near surfaces with high accuracy and repeatability. Distribution of the cells when they reached a steady state shows that the …


Comparative Analysis Of Impact Attenuation Properties From Soccer Headgear, Kevin G. Mciver, Goutham N. Sankaran, Justin J. Markel, Tom M. Talavage, Larry J. Leverenz, Eric A. Nauman Aug 2017

Comparative Analysis Of Impact Attenuation Properties From Soccer Headgear, Kevin G. Mciver, Goutham N. Sankaran, Justin J. Markel, Tom M. Talavage, Larry J. Leverenz, Eric A. Nauman

The Summer Undergraduate Research Fellowship (SURF) Symposium

Athletes suffering from long-term neurocognitive deficiency due to subconcussive impacts is a major concern for football and soccer players today. Football players wear helmets that can help reduce injury risks like skull fractures, and these helmets must meet standard criteria that determinines how well a functional helmet should reduce accelerations of the player’s head. Currently no standard exists for testing soccer headgear despite studies demonstrating soccer players experience similar magnitudes of impacts. In this study, a modal impact hammer was used in conjunction with a Hybrid III 50th percentile test dummy head to simulate impacts experienced by soccer players to …


Bacterial Motility And Its Role In Biofilm Formation, Clayton J. Culp, Arezoo M. Ardekani, Adib Ahmadzadegan Aug 2017

Bacterial Motility And Its Role In Biofilm Formation, Clayton J. Culp, Arezoo M. Ardekani, Adib Ahmadzadegan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Bacterial biofilms are known to cause millions of dollars in damage in the medical industry per year via infection of central venous catheters, urinary catheters, and mechanical heart valves. Unfortunately, there are some characteristics of biofilm formation that are yet to be fully understood. Recently much work has been done to investigate the motility characteristics of bacteria with hopes of better understanding the phenomena of biofilm formation. Still, one of the least understood stages is bacterial attachment or adhesion, a process designed to anchor bacteria in an advantageous environment. Providing a better understanding of bacterial motility near solid interfaces will …


Intrinsic Regulators Of Actomyosin Contractility Engendering Pulsatile Behaviors, Qilin Yu, Jing Li, Taeyoon Kim Aug 2017

Intrinsic Regulators Of Actomyosin Contractility Engendering Pulsatile Behaviors, Qilin Yu, Jing Li, Taeyoon Kim

The Summer Undergraduate Research Fellowship (SURF) Symposium

Actomyosin contractility regulates various biological processes including cell migration, muscle contraction, and tissue morphogenesis. Cell cortex underlying a membrane, which is a representative actomyosin network in eukaryote cells, exhibits dynamic contractile behaviors. Interestingly, the cell cortex shows reversible aggregation of actin and myosin called pulsatile contraction in diverse cellular phenomena, such as embryogenesis and tissue morphogenesis. While contractile behaviors have been studied in several in vitro experiments and computational studies, none of them demonstrated the pulsatile contraction of actomyosin networks observed in vivo. Here, we used an agent-based computational model based on Brownian dynamics to identify factors facilitating the pulsatile …


A Parametric Study Of The Mechanics Of Different Skin Flap Techniques, Steven J. Meza, Adrián Tepole Buganza Aug 2017

A Parametric Study Of The Mechanics Of Different Skin Flap Techniques, Steven J. Meza, Adrián Tepole Buganza

The Summer Undergraduate Research Fellowship (SURF) Symposium

In modern day plastic and reconstructive surgeries numerous skin flap designs have been developed and are used to close open wounds. Skin flaps are developed with the intention of imposing minimal tension in skin closure. Excessive tension can lead to poor blood flow that result in post-surgery complications such as necrosis. Currently there is no standard in choosing a skin flap design and a surgeon's choice is based personal experience. A comparison of the mechanical loading in these various designs has not yet been done. We have developed a parametric study, using finite element analysis, of two advancement skin flaps …


Movement And Distribution Of Bacteria Near Surfaces, Daniel A. Quinkert, Adib Ahmadzadegan, Arezoo M. Ardekani Aug 2016

Movement And Distribution Of Bacteria Near Surfaces, Daniel A. Quinkert, Adib Ahmadzadegan, Arezoo M. Ardekani

The Summer Undergraduate Research Fellowship (SURF) Symposium

Bacteria are found everywhere in nature, including within human/animal bodies, biomedical devices, industrial equipment, oceans and lakes. They can be found in planktonic state within a bulk liquid phase or attached to surfaces with the potential to form biofilms. In this study we are interested in the movement and distribution of bacteria near surfaces. The concentrations and fluid interactions of bacteria were characterized at various distances from a surface. Psuedomonas putida F1 was observed in a suspension near a surface. Bacteria movements were visualized with an inverted microscope at 40x magnification. P. putida F1 exhibited greater density in close proximity …


Mechanical Reliability Of Implantable Polyimide-Based Magnetic Microactuators For Biofouling Removal, Christian G. Figueroa-Espada, Qi Yang, Hyowon Lee Aug 2016

Mechanical Reliability Of Implantable Polyimide-Based Magnetic Microactuators For Biofouling Removal, Christian G. Figueroa-Espada, Qi Yang, Hyowon Lee

The Summer Undergraduate Research Fellowship (SURF) Symposium

Hydrocephalus is a neurological disorder that typically requires a long-term implantation of a shunt system to manage its symptoms. These shunt systems are notorious for their extremely high failure rate. More than 40% of all implanted shunt systems fail within the first year of implantation. On average, 85% of all hydrocephalus patients with shunt systems undergo at least two shunt-revision surgeries within 10 years of implantation. A large portion of this high failure rate can be attributed to biofouling-related obstructions and infections. Previously, we developed flexible polyimide-based magnetic microactuators to remove obstructions formed on hydrocephalus shunts. To test the long-term …


Development Of A Shape Memory Polymer Soft Microgripper, Marshall Tatro, David J. Cappelleri, Wuming Jing Aug 2015

Development Of A Shape Memory Polymer Soft Microgripper, Marshall Tatro, David J. Cappelleri, Wuming Jing

The Summer Undergraduate Research Fellowship (SURF) Symposium

The ability to control microrobots by means of magnetic fields has become of increasing interest to researchers. These robots’ ability to reach places tethered microrobots otherwise could not leads to many possible applications in the body, such as delivering drugs to targeted locations and performing biopsies. This study shows the use of shape memory polymer (SMP) to wirelessly actuate a microgripper to be used by a controllable microrobot to achieve these functions. Many smart materials were analyzed in order to find the material that most effectively would accomplish wirelessly gripping, manipulating, and releasing a microobject. Multiple microgripper designs were designed, …


Indentation Probing Of In Vitro Bovine Articular Cartilage: Effects On Chondrocyte Viability And Tissue Biomechanics, Pablo F. Argote, Alan Poon, Xin Xu Ph.D, Corey P. Neu Ph.D. Aug 2015

Indentation Probing Of In Vitro Bovine Articular Cartilage: Effects On Chondrocyte Viability And Tissue Biomechanics, Pablo F. Argote, Alan Poon, Xin Xu Ph.D, Corey P. Neu Ph.D.

The Summer Undergraduate Research Fellowship (SURF) Symposium

Osteoarthritis (OA) consists of a degenerative disease on articular cartilage, which is prone to excessive mechanical loading and frictional resistance that leads to the wear and tear of the tissue. These factors result in the progressive and incurable disease that affects millions of people worldwide. The goal is to characterize chondrocyte viability and the in vitro biomechanical properties of articular cartilage in two confined indentation studies. One study looks at the chondrocyte viability over seven days. The second compares the immediate effects of strain rates on chondrocyte viability and tissue biomechanics. Bovine cartilage explants are harvested, cultured, and then 40% …


Cell-Matrix Interactions During En Masse Cell Migration, Meng Zhuang, Altug Ozcelikkale, Bumsoo Han Aug 2015

Cell-Matrix Interactions During En Masse Cell Migration, Meng Zhuang, Altug Ozcelikkale, Bumsoo Han

The Summer Undergraduate Research Fellowship (SURF) Symposium

Extended wound care, including prolonged treatment of burn injuries, acute and chronic wounds, is a significant source of patient discomfort and financial burden to public healthcare programs. Both accelerated healing and prevention of scar formation are highly desired but remain to be challenging to achieve. This is primary due to limited understanding of interactions between cells and the surrounding extracellular matrix (ECM) during wound healing. Particularly, collective migration of fibroblasts through provisional matrix, so called en masse migration, is one of these interactions that play a critical role in later stages of granulation tissue formation and wound closure. In addition …


Advancement Of Legged Locomotion Models By Including Nonlinear Damping, Ian Abraham, Zhuohua H. Shen, Justin E. Seipel Oct 2013

Advancement Of Legged Locomotion Models By Including Nonlinear Damping, Ian Abraham, Zhuohua H. Shen, Justin E. Seipel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Accurately predicting human locomotion has been a goal of various mathematical models. Early canonical models of locomotion were developed to predict the basic features of ground reaction forces (GRF). More recently, modified hip actuated and leg damped locomotion models have been developed to better predict the stability and robustness of human and animal locomotion. Such improvements have resulted in the loss of the characteristic GRF predicted by earlier models. Historically, GRF are among the most common measures to experimentally study human locomotion. Thus, it is important to develop new mathematical models that predict both accurate stability of motion, as well …