M.Tech. (Chiropractic) / Purpose: The purpose of this study was to determine if inversion therapy is beneficial for participants with lower back pain and if there is an additive effect when combining it with manipulation. Three treatment approaches were utilized: inversion therapy, lumbar spine manipulations and a combination of inversion therapy with lumbar spine manipulations. Method: Thirty participants who qualified for the study were randomly divided into three equal groups consisting of ten participants each. Depending in which group the participant was allocated, determined if they received lumbar spine manipulation (Group 1), inversion therapy (Group 2), or a combination of inversion therapy performed after the lumbar spine manipulation (Group 3). Procedure: Each participant was treated a total of six times over a course of three weeks, furthermore there was a seventh day of final data collection. The measurements were taken on the first, fourth and seventh visit. Subjective measurements consisted of the numerical pain rating scale (NPRS) and the Oswestry Low Back Pain Disability Index. Objective measurements were done with the inclinometer (lumbar range of motion) and the flexicurve (lumbar lordosis measurement). Results: It is clear that there were statistically significant improvements in all three of the groups in both the NPRS and the Oswestry disability index. The inversion therapy group performed the best with the NPRS and the Oswestry disability index, with the spinal manipulation and combination group following narrowly. However, there were no statistically significant differences on the intergroup analysis with regards to the subjective results. The results of the subjective measurements indicated that there was a relative decrease in lumbar spine lordosis measurements, over the trial period, but with no statistical significance. With the lumbar range of motion-flexion measurements it was clear that the spinal manipulation group and the inversion therapy group had superior results compared to the combination group, with both indicating statistical significance over the trial period. Extension, lateral flexion and rotation did not show any statistical significance over the trial period. Conclusion: There were statistically significant improvements within each of the three groups on intragroup analysis, but no statistically significant differences were found on intergroup analysis. Therefore, none of the groups could be singled out as being the superior treatment for mechanical lower back pain. All three groups’ demonstrated improvement. There was no significant additive effect by combining the two treatments. Therefore there is no benefit to adding inversion therapy to the treatment protocol. Manipulation alone demonstrated to have similar effects. However, should a patient not be able to see a chiropractor for treatment, home based inversion therapy can be beneficial. A concern that should be addressed is that home based treatment wouldn’t be supervised and as such it is not advised to do without some form of professional management. Inversion therapy can definitely be utilized as a home based treatment option for a patient with LBP, patients that can’t make use of regular chiropractic care due too logistical or financial restraints will benefit from inversion therapy home usage. Home usage will provide the patient with regular general traction therapy and can result in patient pain relief, increase overall functioning of the patient and the patient compliance may improve.

When accelerating, traction from the tyres is necessary to move the vehicle forward. If too much torque is applied to the wheels of the vehicle, the tyres will start to spin and thereby the traction will decrease. This can occur when the driver of the vehicle applies to much throttle, but can be controlled with a traction control system that prevent the tyres from spinning and keeps the tyres at maximum traction to increase acceleration. In Formula Student competitions, every tenths of a second gained is vital and a traction control could help the driver to find these tenths of a second during acceleration. The purpose of this bachelor thesis was to design a slip ratio based traction control for the KTH Formula Student car DeV17 with focus on the acceleration event from standing start. A problem with standing start is the launch of the acceleration which were investigated along with a PID-controller. The model was developed in MATLAB's SIMULINK and simulated with IPG CarMaker. Small improvements in acceleration time were seen with the PID-controller but the launch did not see any improvements.

The ability of cells to probe their mechanical environment and react to external stimuli is critical for maintenance of their normal structure and function. Through connections to the extracellular matrix, cells can sense mechanical cues such as substrate rigidity and stretch, and through force transmission across their contractile cytoskeleton can react accordingly to those signals by applying contractile traction forces to their surrounding environment. Healthy cells can react to these mechanical cues to maintain their cytoskeletal prestress (tension) at a set or homeostatic level over time, a phenomenon known as tensional homeostasis. Progression of certain diseases such as asthma, atherosclerosis, and cancer have been linked to a loss of tensional homeostasis. As such, tools for quantifying the traction forces that adhered cells apply to their substrate are crucial for gaining a better understanding of not just how healthy cells interact mechanically with their environment, but also how changes to the extracellular matrix or mutations within the cell can impact their ability to maintain tensional homeostasis and therefore remain both functional and viable. Our group has previously developed a method of quantifying cellular traction forces using indirectly pattered, soft hydrogel substrates known as micropattern traction microscopy. This method was initially developed to create discrete grid micropatterns, which while useful for measuring cellular traction forces does not offer any ability for the user to control cell growth area shape or size. This technique was further improved on through the creation of a protocol for changing discrete grid patterns into isolated island micropatterns, but this two-step process was challenging and generated islands of inconsistent shape and size. Here, we propose a new method for generating isolated island micropatterns of essentially any desired shape and size in a single step, as well as a corresponding image analysis algorithm for calculating cellular traction forces from these island micropatterns. Additionally, this dissertation also includes an investigation into the impact of distinct Epithelial-cadherin mutations on the ability of gastric adenocarcinoma (AGS) cells to achieve tensional homeostasis. Disruption of tensional homeostasis in the epithelium is a hallmark of certain cancers, and mutations in E-cadherin proteins have been identified in malignant epithelial cells. Here, through analysis of AGS cell traction force data collected previously by Dr. Han Xu during her dissertation work, we have found that two distinct mutations in the intracellular domain of E-cadherins have an impact on the ability of AGS cells to achieve tensional homeostasis.

This study presents a novel approach for predicting future cellular traction in a time series. The proposed method leverages two distinct look-ahead Long Short-Term Memory (LSTM) models—one for cell boundary and the other for traction data—to achieve rapid and accurate predictions. These LSTM models are trained using real Fourier Transform Traction Cytometry (FTTC) output data, ensuring consistency and reliability in the underlying calculations. To account for variability among cells, each cell is trained separately, mitigating generalized errors. The predictive performance is demonstrated by accurately forecasting tractions for the next 30-time instances, with an error rate below 7%. Moreover, a strategy for real-time traction calculations is proposed, involving the capture of a bead reference image before cell placement in a controlled environment. By doing so, we eliminate the need for cell removal and enable real-time calculation of tractions. Combining these two ideas, our tool speeds up the traction calculations 1.6 times, leveraging from limiting TFM use. As a walk forward, prediction method is implemented by combining prediction values with real data for future prediction, it is indicative of more speedup. The predictive capabilities of this approach offer valuable insights, with potential applications in identifying cancerous cells based on their traction behavior over time.Additionally, we present an advanced cell boundary detection algorithm that autonomously identifies cell boundaries from obscure cell images, reducing human intervention and bias. This algorithm significantly streamlines data collection, enhancing the efficiency and accuracy of our methodology.

Le contexte de ce projet de recherche est celui de la stabilité des barrages-poids et aborde le besoin d’évaluation de la résistance de l’interface béton-rocher. Puisqu’il est techniquement difficile d’évaluer si l’interface est liée ou non, la cohésion réelle et sa contribution à la résistance au cisaillement sont souvent négligées et ce sujet précis est peu abordé dans la littérature. Un lien direct peut être fait entre cette non-considération et des travaux de stabilisation réalisés sur des ouvrages hydrauliques. Cette étude a comme objectif la caractérisation de la cohésion réelle dans le but de déterminer s’il est sécuritaire d’incorporer sa contribution dans l’évaluation de stabilité des barrages-poids. Pour ce faire, il est nécessaire d’évaluer les comportements en traction et en cisaillement de l’interface et d’analyser comment ils sont affectés par des paramètres importants telle la rugosité de l’interface. Cette caractérisation est faite à l’aide d’un programme expérimental sur 66 répliques d’interfaces béton-rocher en mortier. La rugosité est évaluée à l’aide d’un profilomètre laser et du paramètre Z2. Les répliques ont fait l’objet d’essais de traction directe, de traction par pression de fluide et de cisaillement direct. L’influence de la rugosité d’interface et de la résistance à la compression uniaxiale (UCS) des matériaux sur les résistances à la traction et au cisaillement est évaluée grâce à l’analyse des variances (ANOVA). Des essais supplémentaires ont permis d’approfondir la compréhension du mécanisme de rupture en cisaillement. Les résultats indiquent une résistance à la traction moyenne de l’interface liée de 0,62 MPa et une cohésion (en cisaillement) moyenne de 3,1 MPa. L’ANOVA montre une augmentation significative de la résistance à la traction avec la rugosité et une augmentation significative de la résistance au cisaillement au pic avec la rugosité, l’UCS et la contrainte normale. Il a aussi été observé que le pas d’échantillonnage a un impact important sur la valeur de Z2. Les résultats suggèrent qu’une valeur minimale de cohésion de 100 à 200 kPa pourrait être utilisée dans la mesure où il peut être démontré que l’interface est liée. Cette condition pourrait d’ailleurs constituer un sujet de recherche s’inscrivant dans la continuité des travaux réalisés.

"In this thesis, a cell traction force microscopy method is developed for measuring traction forces of connective tissue cells. This method includes an improved methodology in traction force microscopy of live cells cultured on an elastic substrate. Tissue cells, such as skin and muscle cells respond to the mechanical stimuli of their microenvironment by adhering to their substrate and exerting forces on the proteins of the extracellular matrix (ECM). These forces are called cell traction forces. Fibroblasts are grown on polyacrylamide (PA) gels embedded with fluorescent beads and coated with different types of ECM ligands. Traction forces of NIH 3T3 fibroblasts are calculated from the measured deformations of PA gels by using a 3-D finite element method. The advantages of this method compared to the traditional methods of cell traction force microscopy (CTFM) are that this method takes into account the finite thickness of the substrate by applying a 3-D FEM analysis to reduce the errors of using an infinite half space approximation for a substrate with a finite thickness and that it uses a novel method for embedding the substrate with fluorescent markers that decreases the measurement uncertainties. In our approach fluorescent beads were embedded on the top of substrate instead of getting mixed with the gel. This decreases the effect of out-of-focus fluorescent beads on the measured deformation fields which enhances the accuracy of cell traction force measurements."

L'étude du comportement des sols fins sollicités en traction a suscité l'intérêt des chercheurs et des ingénieurs pour de nombreuses applications depuis plus d'un demi siècle. Cependant, elle est restée sans issues claires, notamment pour l'identification du comportement des sols en traction pour des états de saturations différentes. La complexité est essentiellement d'origine expérimentale. Cette question est de nouveau posée. Des contributions récentes, assez prometteuses, permettent d'apporter un éclairage nouveau sur ces aspects. Ce travail de recherches s'intègre donc dans cette voie, où l'on cherche à apporter des éléments de réponse quant à la faisabilité et à l'interprétation d'un certain nombre d'essais de laboratoire de traction directe ou indirecte.En se focalisant sur la détermination de la résistance à la traction d'un sol fin à un état de saturation donné, on a réalisé des essais au laboratoire sur un limon (assimilé à un matériau fin), se trouvant sur un site choisi initialement pour héberger un centre de stockage des déchets solides ménagers. La problématique relative à ce type d'application, est liée au fait qu'un tel sol (le limon) est utilisé majoritairement pour la construction de la couche de couverture, et qu'il risque donc d'être fortement sollicité en traction par flexion quand les déchets subissent des tassements. Dans ce but, l'étude expérimentale a été orientée vers des essais de traction indirecte à savoir l'essai de fendage et l'essai de flexion.La complexité d'une telle étude réside, d'une part, dans l'interprétation qu'on peut en faire et, d'autre part, dans le couplage des effets de plusieurs paramètres (liés à la préparation de l'échantillon, les conditions initiales de saturation et de densité des échantillons, les dimensions des éprouvettes, les conditions aux limites associées à ces essais).En faisant une étude paramétrique et une analyse fine de la réponse de ce matériau, via une méthodologie numérique qui nous semble bien appropriée (méthode des éléments distincts, DEM), nous avons apporté des éléments de réponse aux interprétations des essais de traction indirecte. L'approche DEM est appliquée selon une démarche de calibrage des paramètres sur la base des essais de cisaillement au triaxial. On montre que l'essai de fendage ne pourrait pas fournir la résistance à la traction uniaxiale (valeur de référence obtenue numériquement par la DEM par un essai de traction directe) même si l'initiation de la fissure apparaissait au centre. Une telle condition n'est satisfaite que pour un aplatissement de l'éprouvette cylindrique d'un angle au centre de la section par rapport à la génératrice variant de 10° à 12°.D'un autre côté, l'essai de flexion interprété selon le modèle différentiel semble donner une bonne estimation de la résistance à la traction uniaxiale.Dans ce travail de recherches, bien que la démarche numérique par éléments distincts semble dépendre des essais de laboratoire nécessaires au calage, sa potentialité demeure très importante puisque, non seulement elle offre l'opportunité de simuler des essais complexes de laboratoire, mais aussi elle permet d'avoir des outils d'interprétation fiables.

Thesis (M.S.)--University of Florida, 2000. / Printout. Vita. Includes bibliographical references (leaves 71-75). Also available on the World Wide Web; PDF reader required.

The peel test is a commonly used testing method for adhesive strength evaluation. The test involves peeling a pressure sensitive tape away from a substrate and measuring the peel force that is applied to rupture the adhesive bond. In the present study, the mechanics of the peel test is analyzed based on a cohesive zone model. Cohesive failure is assumed to prevail in the vicinity of the peel front, that is, the adhesive fails not by debonding from the adherends but by splitting of the adhesive itself. Generally, the failure of the adhesive is accompanied with a process of cavitation and fibrillation. Therefore, the cohesive zone is modeled as a continuous fibrillated region. A Maxwell model is employed to characterize the viscoelastic behavior of the adhesive. The governing equation and boundary conditions that describe the mechanics of the peel test are derived. Numerical results are obtained under steady state conditions. The model predicts the peel force in terms of the peel rate, the peel angle, the nature of the adhesive, and the properties of the backing and the substrate. The traction distribution on the substrate surface is found to depend on various test parameters. Finally, finite element analysis is performed using the commercial software package ABAQUS. The results from FEA are compared with those from the mathematical method to evaluate the validity of the present model. The effective range of the present model is found to be related to the ratio of the critical fibril length to the extent of the cohesive zone. Given the nature of the adhesive as well as the properties of the backing and the substrate, the proposed model is able to predict the peel force and the traction distribution in terms of the peel rate and the peel angle, and thus provides a measure of the strength of the adhesive bond.

The peel test is a commonly used testing method for adhesive strength evaluation. The test involves peeling a pressure sensitive tape away from a substrate and measuring the peel force that is applied to rupture the adhesive bond. In the present study, the mechanics of the peel test is analyzed based on a cohesive zone model. Cohesive failure is assumed to prevail in the vicinity of the peel front, that is, the adhesive fails not by debonding from the adherends but by splitting of the adhesive itself. Generally, the failure of the adhesive is accompanied with a process of cavitation and fibrillation. Therefore, the cohesive zone is modeled as a continuous fibrillated region. A Maxwell model is employed to characterize the viscoelastic behavior of the adhesive. The governing equation and boundary conditions that describe the mechanics of the peel test are derived. Numerical results are obtained under steady state conditions. The model predicts the peel force in terms of the peel rate, the peel angle, the nature of the adhesive, and the properties of the backing and the substrate. The traction distribution on the substrate surface is found to depend on various test parameters. Finally, finite element analysis is performed using the commercial software package ABAQUS. The results from FEA are compared with those from the mathematical method to evaluate the validity of the present model. The effective range of the present model is found to be related to the ratio of the critical fibril length to the extent of the cohesive zone. Given the nature of the adhesive as well as the properties of the backing and the substrate, the proposed model is able to predict the peel force and the traction distribution in terms of the peel rate and the peel angle, and thus provides a measure of the strength of the adhesive bond.