Rodney D. Averett

Exponent · Biomechanics

Computational models for simulating and predicting fibrin fiber fracture are important tools for studying bulk mechanical properties and mechanobiological response of fibrin networks in physiological conditions. In this work, we employed a new strategy to model the mechanical response of a single fibrin fiber using a collection of bundled protofibr...

Evaporation studies of water using classical molecular dynamics simulations are largely limited due to its high computational expense. We aim at addressing the computational issues by developing a coarse grain model for evaporation of water on solid surfaces by combining four water molecules into a single bead. Most commonly used mono atomic pair p...

The multiscale mechanical behavior of individual fibrin fibers and fibrin clots wasmodeled by coupling atomistic simulation data and microscopic experimental data. We propose anew protofibril element composed of a nonlinear spring network, and constructed this based onmolecular simulations and atomic force microscopy results to simulate the force e...

The field of thrombosis and hemostasis is crucial for understanding and developing new therapies for pathologies such as deep vein thrombosis, diabetes related strokes, pulmonary embolisms, and hemorrhaging related diseases. In the last two decades, an exponential growth in studies related to fibrin clot formation using computational tools has been...

Understanding and controlling the interaction between nanoparticles and cell nuclei is critical to the development of the biomedical applications such as gene delivery, cellular imaging, and tumor therapy. Recent years have witnessed growing evidence that the size, shape, and the grafting density of the karyopherins ligands of nanoparticles provide...

Medical studies have consistently shown that the best defense against cancer is early detection. Due to this, many efforts have been made to develop methods of screening patient blood quickly and cheaply. These methods range from separation via differences in size, electrostatic potential, chemical potential, antibody-binding affinity, among others...

The study on the polymerization of fibrinogen molecules into fibrin monomers and eventually a stable, mechanically robust fibrin clot is a persistent and enduring topic in the field of thrombosis and hemostasis. Despite many research advances in fibrin polymerization, the change in the structure of fibrin clots and its influence on the formation of...

Although in vivo studies have been conducted in the past to determine hyperglycemic effects and influence on clotting risk in patients with diabetes, the true extent of hyperglycemia on unstable and spontaneous clot formation remains highly debated. Factors such as increased glycation, elevated fibrinogen concentration, elevated prothrombin levels,...

The multiscale behavior of the individual fibrin fibers and fibrin clots is modeled by coupling atomistic simulation data and microscopic experimental data. We propose a protofibril element made up of nonlinear spring network, constructed based on the molecular simulation and atomic force microscopy results to simulate the force extension behavior...

Background: Fibrin formation and dissolution are attributed to cascades of protease activation concluding with thrombin activation, and plasmin proteolysis for fibrin breakdown. Cysteine cathepsins are powerful proteases secreted by endothelial cells and others during cardiovascular disease and diabetes. Their fibrinolytic activity and putative ro...

Sickle cell disease is caused by the amino acid substitution of glutamic acid to valine, which leads to the polymerization of deoxygenated sickle hemoglobin (HbS) into long strands. These strands are responsible for the sickling of red blood cells (RBCs), making blood hyper-coagulable leading to an increased chance of vaso-occlusive crisis. The con...

Studies suggest that patients with deep vein thrombosis and diabetes often have hypercoagulable blood plasma, leading to a higher risk of thromboembolism formation through the rupture of blood clots, which may lead to stroke and death. Despite many advances in the field of blood clot formation and thrombosis, the influence of mechanical properties...

Cysteine cathepsins are powerful proteases first identified in lysosomes responsible for protein turnover, but now known to degrade collagen, elastin, and other matrix proteins. They are upregulated during atherosclerotic plaque development, and elevated cathepsin plasma levels are biomarkers for cardiovascular disease. The ability of cysteine cath...

Blood clots occur in the human body when they are required to prevent bleeding. In pathological states such as diabetes and sickle cell disease, blood clots can also form undesirably due to hypercoagulable plasma conditions. With the continued effort in developing fibrin therapies for potential life-saving solutions, more mechanical modeling is nee...

The study of thrombosis is crucial to understand and develop new therapies for diseases like deep vein thrombosis, diabetes related strokes, pulmonary embolism etc. The last two decades have seen an exponential growth in studies related to the blood clot formation using computational tools and through experiments. Despite of this growth, the comple...

Fibrin clot formation is a proteolytic cascade of events with thrombin and plasmin identified as the main proteases cleaving fibrinogen precursor, and the fibrin polymer, respectively. Other proteases may be involved directly in fibrin(ogen) cleavage, clot formation, and resolution, or in the degradation of fibrin-based scaffolds emerging as useful...

Studies suggests that patients with deep vein thrombosis and diabetes often have hy-per coagulable blood plasma leading to higher chances of forming thromboembolisms by the rupture of blood clots, which may lead to stroke and death. Despite the advances in the field of blood clot formation and lysis research, the change in mechanical properties and...

Artificial membranes mimicking biological structures are rapidly breaking new ground in the areas of medicine and soft-matter physics. In this endeavor, we use dissipative particle dynamic (DPD) simulation to investigate the morphology and behavior of lipid-based biomembranes under conditions of varied lipid density and self-interaction. Our result...

Recent studies have shown that ultrasound is used to open drug-carrying liposomes to release their payloads; however, a shockwave energetic enough to rupture lipid membranes can cause collateral damage to surrounding cells. Similarly, a destructive shockwave, which may be used to rupture a cell membrane in order to lyse the cell (e.g., as in cancer...

In this research article, a computational imaging analysis method is presented for the evaluation of aggregation and anisotropy in both native (unglycated) and glycated fibrin matrix structures. The imaging analysis was used to test the hypothesis that glycated fibrin structures are more aggregated and anisotropic than unglycated (native) fibrin st...

We developed a new mechanical model for determining the compression and shear mechanical behavior of four different hemoglobin structures. Previous studies on hemoglobin structures have focused primarily on overall mechanical behavior; however, this study investigates the mechanical behavior of hemoglobin, a major constituent of red blood cells (RB...

Sickle cell disease is a single point mutation disease that is known to alter the coagulation system, leading to hypercoagulable plasma conditions. These hypercoagulable conditions can lead to complications in the vasculature, caused by fibrin clots that form undesirably. There is a need to understand the morphology and structure of fibrin clots fr...

Blood clots occur in the human body when they are required to prevent bleeding. In pathological states such as diabetes and sickle cell disease, blood clots can also form undesirably due to hypercoagulable plasma conditions. With the continued effort in developing fibrin therapies for potential life-saving solutions, more mechanical modeling is nee...

Fibrin is an extracellular matrix protein that is responsible for maintaining the structural integrity of blood clots. Much research has been done on fibrin in the past years to include the investigation of synthesis, structure-function, and lysis of clots. There is still much unknown about the morphological and structural features of clots that en...

In this study, a novel technique was developed in which magnetic microparticles (MMPs) and quantum dots (QDs) were successfully incorporated into fibrin clots. The MMPs were added at concentrations of 0.1 wt% and 1 wt% of the fibrin content in an effort to determine if a magnetic field could be utilized to mechanically stretch the fibrin network, s...

The constitutive behavior of poly(ethylene terephthalate) (PET) unreinforced (control) and PET fibers reinforced with 5 wt% vapor‐grown carbon nanofibers (VGCNFs) under uniaxial tension and subsequent to fatigue loading has been evaluated utilizing various analytical models. Two types of fatigue tests were performed: (1) Long cycle fatigue at 50 Hz...

We tested what to our knowledge is a new computational model for fibrin fiber mechanical behavior. The model is composed of three distinct elements: the folded fibrinogen core as seen in the crystal structure, the unstructured α-C connector, and the partially folded α-C domain. Previous studies have highlighted the importance of all three regions a...

The mechanical and fatigue behavior of neat poly(lactic acid) (PLA) films and PLA films reinforced with 5 wt% nanoclay particles has been examined using various analytical procedures. The results showed that for the films tested in this study, PLA-5 wt% samples were more susceptible to crazing at the same maximum fatigue stress as the neat PLA samp...

A set of experiments has been performed on poly(ethylene terephthalate) (PET control) and PET fibers with vapor grown carbon nanofibers (PET–VGCNF) to assess the mechanical integrity of the materials due to a repeated cyclic loading. Artificial neural networks (ANNs) have been used to examine the residual strength and elastic modulus degradation be...

Poly(ethylene terephthalate) (PET) control fibers (nominal diameter ∼24 ± 3 μm) and PET fibers with embedded vapor-grown carbon nanofibers (PET-VGCNF) (nominal diameter ∼25 ± 2 μm) were exposed to cyclic loading and monotonic tensile tests. The control fibers were processed through a typical melt-blending technique and the PET-VGCNF samples were pr...

The objective of the current research was to contribute to the area of mechanics of composite polymeric materials. This objective was reached by establishing a quantitative assessment of the fatigue strength and evolution of mechanical property changes during fatigue loading of nanocomposite fibers and films. Both experimental testing and mathemati...

The deformation and fracture behavior of partially oriented nylon 66 fibers with a diameter approximately 33μm exposed to uniaxial monotonic and cyclic loading was studied using a unique test technique. Prior cyclic deformation resulted in a ratchet strain as well as a decrease in residual strength and ductility of the fibers. A description of the...

A fracture mechanics protocol appropriate for small fibers (35 micron diameter) is presented, which allows for the determination of the strength limitations of high performance nylon 6,6 fibers. Specifically, linear elastic fracture mechanics (LEFM) techniques are employed in addition to elastic-plastic fracture mechanics (EPFM) theories to achieve...