Visualization of MG53-mediated Cell Membrane Repair Using in vivo and in vitro Systems

Repair of acute injury to the cell membrane is an elemental process of normal cellular physiology, and defective membrane repair has been linked to many degenerative human diseases. The recent discovery of MG53 as a key component of the membrane resealing machinery allows for a better molecular understanding of the basic biology of tissue repair, as well as for potential translational applications in regenerative medicine. Here we detail the experimental protocols for exploring the in vivo function of MG53 in repair of muscle injury using treadmill exercise protocols on mouse models, for testing the ex vivo membrane repair capacity by measuring dye entry into isolated muscle fibers, and for monitoring the dynamic process of MG53-mediated vesicle trafficking and cell membrane repair in cultured cells using live cell confocal microscopy

A Hybrid Process Integrating Reverse Engineering, Pre-Repair Processing, Additive Manufacturing, and Material Testing for Component Remanufacturing

Metallic components can gain defects such as dents, cracks, wear, heat checks, deformation, etc., that need to be repaired before reinserting into service for extending the lifespan of these parts. In this study, a hybrid process was developed to integrate reverse engineering, pre-repair processing, additive manufacturing, and material testing for the purpose of part remanufacturing. Worn components with varied defects were scanned using a 3D scanner to recreate the three-dimensional models. Pre-repair processing methods which include pre-repair machining and heat-treatment were introduced. Strategies for pre-repair machining of defects including surface impact damage, surface superficial damage and cracking were presented. Pre-repair heat-treatment procedure for H13 tool steel which was widely used in die/mold application was introduced. Repair volume reconstruction methodology was developed to regain the missing geometry on worn parts. The repair volume provides a geometry that should be restored in the additive manufacturing process. A damaged component was repaired using the directed energy deposition process to rebuild the worn geometry. The repaired part was inspected in microstructure and mechanical aspects to evaluate the repair. The hybrid process solved key issues associated with repair, providing a solution for automated metallic component remanufacturing

An Investigation of High-Speed Consolidation and Repair of Carbon Fiber - Epoxy Composites Through Ultrasonic Welding

Adhesive repair of carbon fiber composite structures is commonly done on damaged structures to extend the service life. This method requires careful preparation of the damaged surface with intricate steps to ensure good bonding between the repair patch and the parent structure by means of an adhesive film. As with many forms of composite manufacturing, it is required to perform vacuum bagging, debulking, and a heated cure depending on the resin. All these steps make the repair process costly and time consuming. In this present work, an alternative method of repair is investigated which explores the experimental feasibility of using ultrasonic vibrations as a substitute to the vacuum bagging and debulking steps. This would ultimately reduce the manufacturing time, labor, and cost. Ultrasonic welding parameters were explored (time, travel, force, and amplitude) with two welding modes to optimize the consolidation process. Welded specimens were then post-cured in the oven following the recommended cure cycle from the manufacturer. Temperature measurements were obtained during the welding process and cure kinetics and viscosity behavior were predicted using semi-empirical models developed for Cycom 5320. Interlaminar shear strength was compared for welded and vacuum bagged samples. Repair of composite structures was simulated by applying flat repair patches over an open-hole and testing in uniaxial tension. The strength recovery was compared for welded and vacuum bagged repair samples

MuAlloy : an automated mutation system for alloy

textMutation is a powerful technique that researchers have studied for several decades in the context of imperative code. For example, mutation testing is commonly considered a '"gold standard"' for test suite quality. Mutation in the context of declarative languages is a less studied problem. This thesis introduces a foundation for mutation-driven analyses for Alloy, a first-order, declarative language based on relations. Specifically, we introduce a family of mutation operators for Alloy models and define algorithms for applying the operators on different parts of the models. We embody these operators and algorithms in our prototype tool MuAlloy that provides a GUI-based front-end for customizing the application of mutation operators. To demonstrate the potential of our approach, we illustrate the use of MuAlloy in two application scenarios: (1) mutation testing for Alloy (in the spirit of traditional mutation testing for imperative languages); and (2) program repair for Alloy using mutation.Electrical and Computer Engineerin

Improving Loss Estimation for Woodframe Buildings. Volume 2: Appendices

This report documents Tasks 4.1 and 4.5 of the CUREE-Caltech Woodframe Project. It presents a theoretical and empirical methodology for creating probabilistic relationships between seismic shaking severity and physical damage and loss for buildings in general, and for woodframe buildings in particular. The methodology, called assembly-based vulnerability (ABV), is illustrated for 19 specific woodframe buildings of varying ages, sizes, configuration, quality of construction, and retrofit and redesign conditions. The study employs variations on four basic floorplans, called index buildings. These include a small house and a large house, a townhouse and an apartment building. The resulting seismic vulnerability functions give the probability distribution of repair cost as a function of instrumental ground-motion severity. These vulnerability functions are useful by themselves, and are also transformed to seismic fragility functions compatible with the HAZUS software. The methods and data employed here use well-accepted structural engineering techniques, laboratory test data and computer programs produced by Element 1 of the CUREE-Caltech Woodframe Project, other recently published research, and standard construction cost-estimating methods. While based on such well established principles, this report represents a substantially new contribution to the field of earthquake loss estimation. Its methodology is notable in that it calculates detailed structural response using nonlinear time-history structural analysis as opposed to the simplifying assumptions required by nonlinear pushover methods. It models physical damage at the level of individual building assemblies such as individual windows, segments of wall, etc., for which detailed laboratory testing is available, as opposed to two or three broad component categories that cannot be directly tested. And it explicitly models uncertainty in ground motion, structural response, component damageability, and contractor costs. Consequently, a very detailed, verifiable, probabilistic picture of physical performance and repair cost is produced, capable of informing a variety of decisions regarding seismic retrofit, code development, code enforcement, performance-based design for above-code applications, and insurance practices

Assessment of Bridges Subjected to Vehicular Collision

Vehicles often collide with bridges. However, there are no available guidelines for bridge inspectors to assess damage and to make repair decisions. This project addresses this gap by investigating the behavior of steel girder bridges subjected to vehicular collision through (1) performing non-destructive field testing, (2) developing validated numerical models, and (3) performing parametric investigations to extend research findings. Field testing was performed using Digital Image Correlation (DIC) - a portable, non-destructive, photographic measurement technique. The focus was on two- and three-span continuous multi-girder steel bridges for which an exterior girder has sustained Category T damage, i.e., torsion about the longitudinal direction. This project can benefit Indiana Department of Transportation (INDOT) business processes by potentially reducing the number or amount of repairs, leading to cost savings and longer lifespans for bridges

The performance of ultrasonic pulse velocity on the prediction of tensile granite behaviour : a study based on artificial neural networks

The rehabilitation and repair of existing structures requires inspection. This generally includes in situ non-destructive testing. A very economical test is the non-destructive ultrasonic pulse velocity test (UPV). Lower information is available in the literature in relation to the use of this technique for the estimation of the tensile strength of materials. Therefore, this paper aims at using artificial neural networks (ANN) in the prediction of the mechanical behaviour of granites under tensile loading. The parameters under analysis are the tensile strength, displacement at peak stress and critical crack opening. For this, experimental results obtained from the physical and mechanical characterization under tension of distinct types of granites are combined and the performance of the developed models using the UPV index alone and combined with other physical parameters is analysed. The results of the ANNs models are also compared with respect to the results of regression models. The criteria used to evaluate the predictive performances of the models were the coefficient of correlation (R) and root mean square error (RMSE)

Optimization and Validation of a Human <i>Ex Vivo</i> Femoral Head Model for Preclinical Cartilage Research and Regenerative Therapies

OBJECTIVE: Articular cartilage is incapable of effective repair following injury or during osteoarthritis. While there have been developments in cartilage repair technologies, there is a need to advance biologically relevant models for preclinical testing of biomaterial and regenerative therapies. This study describes conditions for the effective ex vivo culture of the whole human femoral head. DESIGN: Fresh, viable femoral heads were obtained from femoral neck fractures and cultured for up to 10 weeks in (a) Dulbecco’s modified Eagle’s medium (DMEM); (b) DMEM + mixing; (c) DMEM + 10% human serum (HS); (d) DMEM + 10% HS + mixing. The viability, morphology, volume, and density of fluorescently labelled in situ chondrocytes and cartilage surface roughness were assessed by confocal microscopy. Cartilage histology was studied for glycosaminoglycan content using Alcian blue and collagen content using picrosirius red. RESULTS: Chondrocyte viability remained at >95% in DMEM + 10% HS. In DMEM alone, viability remained high for ~4 weeks and then declined. For the other conditions, superficial zone chondrocyte viability fell to 0.05). CONCLUSIONS: In this ex vivo model, chondrocyte viability was maintained in human femoral heads for up to 10 weeks in culture, a novel finding not previously reported. This human model could prove invaluable for the exploration, development, and assessment of preclinical cartilage repair and regenerative therapies