Ultrasound Transient Shear Wave Elasticity Imaging for Tendon Tissue

Degeneration of tendon tissue is a common cause of tendon dysfunction with the symptoms of repeated episodes of pain and palpable increase of tendon thickness. Tendon mechanical properties are directly related to its physiological composition and the structural organization of the interior collagen fibers which could be altered by tendon degeneration due to overuse or injury. Thus, measuring mechanical properties of tendon tissue may represent a quantitative measurement of pain, reduced function, and tissue health. Ultrasound elasticity imaging has been developed in the last two decades and has proved to be a promising tool for tissue elasticity imaging. To date, however, well established protocols of tendinopathy elasticity imaging for diagnosing tendon degeneration in early stages or late stages do not exist. This thesis describes the re-creation of one dynamic ultrasound elasticity imaging method and the development of an ultrasound transient shear wave elasticity imaging platform for tendon and other musculoskeletal tissue imaging. An experimental mechanical stage with proper supporting systems and accurate translating stages was designed and made. A variety of high-quality tissue-mimicking phantoms were made to simulate homogeneous and heterogeneous soft tissues as well as tendon tissues. A series of data acquisition and data processing programs were developed to collect the displacement data from the phantom and calculate the shear modulus and Young’s modulus of the target. The imaging platform was found to be capable of conducting comparative measurements of the elastic parameters of the phantoms and quantitatively mapping elasticity onto ultrasound B-Mode images. This suggests the system has great potential for not only benefiting individuals with tendinopathy with an earlier detection, intervention and better rehabilitation, but also for providing a medical tool for quantification of musculoskeletal tissue dysfunction in other regions of the body such as the shoulder, elbow and knee.

Preparation of Coated Microtools for Electrochemical Machining Applications

PREPARATION OF COATED MICROTOOLS FOR ELECTROCHEMICAL MACHINING APPLICATIONS Ajaya K. Swain, M.S. University of Nebraska, 2010 Advisor: K.P. Rajurkar Coated tools have improved the performance of both traditional and nontraditional machining processes and have resulted in higher material removal, better surface finish, and increased wear resistance. However, a study on the performance of coated tools in micromachining has not yet been adequately conducted. One possible reason is the difficulties associated with the preparation of coated microtools. Besides the technical requirement, economic and environmental aspects of the material and the coating technique used also play a significant role in coating microtools. This, in fact, restricts the range of coating materials and the type of coating process. Handling is another major issue in case of microtools purely because of their miniature size. This research focuses on the preparation of coated microtools for pulse electrochemical machining by electrodeposition. The motivation of this research is derived from the fact that although there were reports of improved machining by using insulating coatings on ECM tools, particularly in ECM drilling operations, not much literature was found relating to use of metallic coating materials in other ECM process types. An ideal ECM tool should be good thermal and electrical conductor, corrosion resistant, electrochemically stable, and stiff enough to withstand electrolyte pressure. Tungsten has almost all the properties desired in an ECM tool material except being electrochemically unstable. Tungsten can be oxidized during machining resulting in poor machining quality. Electrochemical stability of a tungsten ECM tool can be improved by electroplating it with nickel which has superior electrochemical resistance. Moreover, a tungsten tool can be coated in situ reducing the tool handling and breakage frequency. The tungsten microtool was electroplated with nickel with direct and pulse current. The effect of the various input parameters on the coating characteristics was studied and performance of the coated microtool was evaluated in pulse ECM. The coated tool removed more material (about 28%) than the uncoated tool under similar conditions and was more electrochemical stable. It was concluded that nickel coated tungsten microtool can improve the pulse ECM performance.

Aprimoramento de um baropodômetro eletrônico e análise de estabiliometria em voluntários com escoliose

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of Clinically Invisible, but Optical Coherence Tomography Detected, Optic Disc Margin Anatomy on Neuroretinal Rim Evaluation

PURPOSE. We previously demonstrated that most eyes have regionally variable extensions of Bruch's membrane (BM) inside the clinically identified disc margin (DM) that are clinically and photographically invisible. We studied the impact of these findings on DM- and BM opening (BMO)-derived neuroretinal rim parameters. METHODS. Disc stereo-photography and spectral domain optical coherence tomography (SD-OCT, 24 radial B-scans centered on the optic nerve head) were performed on 30 glaucoma patients and 10 age-matched controls. Photographs were colocalized to SD-OCT data such that the DM and BMO could be visualized in each B-scan. Three parameters were computed: (1) DM-horizontal rim width (HRW), the distance between the DM and internal limiting membrane (ILM) along the DM reference plane; (2) BMO-HRW, the distance between BMO and ILM along the BMO reference plane; and (3) BMO-minimum rim width (MRW), the minimum distance between BMO and ILM. Rank-order correlations of sectors ranked by rim width and spatial concordance measured as angular distances between equivalently ranked sectors were derived. RESULTS. The average DM position was external to BMO in all quadrants, except inferotemporally. There were significant sectoral differences among all three rim parameters. DM- HRW and BMO-HRW sector ranks were better correlated (median rho = 0.84) than DM- HRW and BMO-MRW (median rho = 0.55), or BMO-HRW and BMO-MRW (median rho = 0.60) ranks. Sectors with the narrowest BMO-MRW were infrequently the same as those with the narrowest DM-HRW or BMO-HRW. CONCLUSIONS. BMO-MRW quantifies the neuroretinal rim from a true anatomical outer border and accounts for its variable trajectory at the point of measurement. (Invest Ophthalmol Vis Sci. 2012;53:1852-1860) DOI:10.1167/iovs.11-9309

Optic Disc Margin Anatomy in Patients with Glaucoma and Normal Controls with Spectral Domain Optical Coherence Tomography

Objective: To characterize optic nerve head (ONH) anatomy related to the clinical optic disc margin with spectral domain-optical coherence tomography (SD-OCT). Design: Cross-sectional study. Participants: Patients with open-angle glaucoma with focal, diffuse, and sclerotic optic disc damage, and age-matched normal controls. Methods: High-resolution radial SD-OCT B-scans centered on the ONH were analyzed at each clock hour. For each scan, the border tissue of Elschnig was classified for obliqueness (internally oblique, externally oblique, or nonoblique) and the presence of Bruch's membrane overhanging the border tissue. Optic disc stereophotographs were co-localized to SD-OCT data with customized software. The frequency with which the disc margin identified in stereophotographs coincided with (1) Bruch's membrane opening (BMO), defined as the innermost edge of Bruch's membrane; (2) Bruch's membrane/border tissue, defined as any aspect of either outside BMO or border tissue; or (3) border tissue, defined as any aspect of border tissue alone, in the B-scans was computed at each clock hour. Main Outcome Measures: The SD-OCT structures coinciding with the disc margin in stereophotographs. Results: There were 30 patients (10 with each type of disc damage) and 10 controls, with a median (range) age of 68.1 (42-86) years and 63.5 (42-77) years, respectively. Although 28 patients (93%) had 2 or more border tissue configurations, the most predominant one was internally oblique, primarily superiorly and nasally, frequently with Bruch's membrane overhang. Externally oblique border tissue was less frequent, observed mostly inferiorly and temporally. In controls, there was predominantly internally oblique configuration around the disc. Although the configurations were not statistically different between patients and controls, they were among the 3 glaucoma groups. At most locations, the SD-OCT structure most frequently identified as the disc margin was some aspect of Bruch's membrane and border tissue external to BMO. Bruch's membrane overhang was regionally present in the majority of patients with glaucoma and controls; however, in most cases it was not visible as the disc margin. Conclusions: The clinically perceived disc margin is most likely not the innermost edge of Bruch's membrane detected by SD-OCT. These findings have important implications for the automated detection of the disc margin and estimates of the neuroretinal rim. Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references. Ophthalmology 2012;119:738-747 (C) 2012 by the American Academy of Ophthalmology.

Development and characterization of a distributed measurement system for the evaluation of voltage quality in electric power networks

The research activity carried out during the PhD course in Electrical Engineering belongs to the branch of electric and electronic measurements. The main subject of the present thesis is a distributed measurement system to be installed in Medium Voltage power networks, as well as the method developed to analyze data acquired by the measurement system itself and to monitor power quality. In chapter 2 the increasing interest towards power quality in electrical systems is illustrated, by reporting the international research activity inherent to the problem and the relevant standards and guidelines emitted. The aspect of the quality of voltage provided by utilities and influenced by customers in the various points of a network came out only in recent years, in particular as a consequence of the energy market liberalization. Usually, the concept of quality of the delivered energy has been associated mostly to its continuity. Hence the reliability was the main characteristic to be ensured for power systems. Nowadays, the number and duration of interruptions are the “quality indicators” commonly perceived by most customers; for this reason, a short section is dedicated also to network reliability and its regulation. In this contest it should be noted that although the measurement system developed during the research activity belongs to the field of power quality evaluation systems, the information registered in real time by its remote stations can be used to improve the system reliability too. Given the vast scenario of power quality degrading phenomena that usually can occur in distribution networks, the study has been focused on electromagnetic transients affecting line voltages. The outcome of such a study has been the design and realization of a distributed measurement system which continuously monitor the phase signals in different points of a network, detect the occurrence of transients superposed to the fundamental steady state component and register the time of occurrence of such events. The data set is finally used to locate the source of the transient disturbance propagating along the network lines. Most of the oscillatory transients affecting line voltages are due to faults occurring in any point of the distribution system and have to be seen before protection equipment intervention. An important conclusion is that the method can improve the monitored network reliability, since the knowledge of the location of a fault allows the energy manager to reduce as much as possible both the area of the network to be disconnected for protection purposes and the time spent by technical staff to recover the abnormal condition and/or the damage. The part of the thesis presenting the results of such a study and activity is structured as follows: chapter 3 deals with the propagation of electromagnetic transients in power systems by defining characteristics and causes of the phenomena and briefly reporting the theory and approaches used to study transients propagation. Then the state of the art concerning methods to detect and locate faults in distribution networks is presented. Finally the attention is paid on the particular technique adopted for the same purpose during the thesis, and the methods developed on the basis of such approach. Chapter 4 reports the configuration of the distribution networks on which the fault location method has been applied by means of simulations as well as the results obtained case by case. In this way the performance featured by the location procedure firstly in ideal then in realistic operating conditions are tested. In chapter 5 the measurement system designed to implement the transients detection and fault location method is presented. The hardware belonging to the measurement chain of every acquisition channel in remote stations is described. Then, the global measurement system is characterized by considering the non ideal aspects of each device that can concur to the final combined uncertainty on the estimated position of the fault in the network under test. Finally, such parameter is computed according to the Guide to the Expression of Uncertainty in Measurements, by means of a numeric procedure. In the last chapter a device is described that has been designed and realized during the PhD activity aiming at substituting the commercial capacitive voltage divider belonging to the conditioning block of the measurement chain. Such a study has been carried out aiming at providing an alternative to the used transducer that could feature equivalent performance and lower cost. In this way, the economical impact of the investment associated to the whole measurement system would be significantly reduced, making the method application much more feasible.

A multilevel converter structure for grid-connected PV plants

A new conversion structure for three-phase grid-connected photovoltaic (PV) generation plants is presented and discussed in this Thesis. The conversion scheme is based on two insulated PV arrays, each one feeding the dc bus of a standard 2-level three-phase voltage source inverter (VSI). Inverters are connected to the grid by a traditional three-phase transformer having open-end windings at inverters side and either star or delta connection at the grid side. The resulting conversion structure is able to perform as a multilevel VSI, equivalent to a 3-level inverter, doubling the power capability of a single VSI with given voltage and current ratings. Different modulation schemes able to generate proper multilevel voltage waveforms have been discussed and compared. They include known algorithms, some their developments, and new original approaches. The goal was to share the grid power with a given ratio between the two VSI within each cycle period of the PWM, being the PWM pattern suitable for the implementation in industrial DSPs. It has been shown that an extension of the modulation methods for standard two-level inverter can provide a elegant solution for dual two-level inverter. An original control method has been introduced to regulate the dc-link voltages of each VSI, according to the voltage reference given by a single MPPT controller. A particular MPPT algorithm has been successfully tested, based on the comparison of the operating points of the two PV arrays. The small deliberately introduced difference between two operating dc voltages leads towards the MPP in a fast and accurate manner. Either simulation or experimental tests, or even both, always accompanied theoretical developments. For the simulation, the Simulink tool of Matlab has been adopted, whereas the experiments have been carried out by a full-scale low-voltage prototype of the whole PV generation system. All the research work was done at the Lab of the Department of Electrical Engineering, University of Bologna.

Polymer nanoparticles : their functionalization for biomedical applications and dynamics near an electrode

In this work, a method for the functionalization of biocompatible, poly(lactic acid)-based nanoparticles with charged moieties or fluorescent labels is presented. Therefore, a miniemulsion solvent evaporation procedure is used in which prepolymerized poly(L-lactic acid) is used together with a previously synthesized copolymer of methacrylic acid or a polymerizable dye, respectively, and an oligo(lactic acid) macromonomer. Alternatively, the copolymerization has been carried out in one step with the miniemulsion solvent evaporation. The increased stability in salty solutions of the carboxyl-modified nanoparticles compared to nanoparticles consisting of poly(lactic acid) only has been shown in light scattering experiments. The properties of the nanoparticles that were prepared with the separately synthesized copolymer were almost identical to those in which the copolymerization and particle fabrication were carried out simultaneously. During the characterization of the fluorescently labeled nanoparticles, the focus was on the stable bonding between the fluorescent dye and the rest of the polymer chain to ensure that none of it is released from the particles, even after longer storage time or during lengthy experiments. In a fluorescence correlation spectroscopy experiment, it could be shown that even after two weeks, no dye has been released into the solvent. Besides biomedical research for which the above described, functionalized nanoparticles were optimized, nanoparticles also play a role in coating technology. One possibility to fabricate coatings is the electrophoretic deposition of particles. In this process, the mobility of nanoparticles near electrode interfaces plays a crucial role. In this thesis, the nanoparticle mobility has been investigated with resonance enhanced dynamic light scattering (REDLS). A new setup has been developed in which the evanescent electromagnetic eld of a surface plasmon that propagates along the gold-sample interface has been used as incident beam for the dynamic light scattering experiment. The gold layer that is necessary for the excitation of the plasmon doubles as an electrode. Due to the penetration depth of the surface plasmon into the sample layer that is limited to ca. 200 nm, insights on the voltage- and frequency dependent mobility of the nanoparticles near the electrode could be gained. Additionally, simultaneous measurements at four different scattering angles can be carried out with this setup, therefore the investigation of samples undergoing changes is feasible. The results were discussed in context with the mechanisms of electrophoretic deposition.

Finite element modeling of flow/compression-induced deformation of alginate scaffolds for bone tissue engineering

Trauma or degenerative diseases such as osteonecrosis may determine bone loss whose recover is promised by a "tissue engineering“ approach. This strategy involves the use of stem cells, grown onboard of adequate biocompatible/bioreabsorbable hosting templates (usually defined as scaffolds) and cultured in specific dynamic environments afforded by differentiation-inducing actuators (usually defined as bioreactors) to produce implantable tissue constructs. The purpose of this thesis is to evaluate, by finite element modeling of flow/compression-induced deformation, alginate scaffolds intended for bone tissue engineering. This work was conducted at the Biomechanics Laboratory of the Institute of Biomedical and Neural Engineering of the Reykjavik University of Iceland. In this respect, Comsol Multiphysics 5.1 simulations were carried out to approximate the loads over alginate 3D matrices under perfusion, compression and perfusion+compression, when varyingalginate pore size and flow/compression regimen. The results of the simulations show that the shear forces in the matrix of the scaffold increase coherently with the increase in flow and load, and decrease with the increase of the pore size. Flow and load rates suggested for proper osteogenic cell differentiation are reported.

Detecting Improvised Explosive Devices Via Forward Looking Ground Penetrating Radar

Forward-looking ground penetrating radar shows promise for detection of improvised explosive devices in active war zones. Because of certain insurmountable physical limitations, post-processing algorithm development is the most popular research topic in this field. One such investigative avenue explores the worthiness of frequency analysis during data post-processing. Using the finite difference time domain numerical method, simulations are run to test both mine and clutter frequency response. Mines are found to respond strongest at low frequencies and cause periodic changes in ground penetrating radar frequency results. These results are called into question, however, when clutter, a phenomenon generally known to be random, is also found to cause periodic frequency effects. Possible causes, including simulation inaccuracy, are considered. Although the clutter models used are found to be inadequately random, specular reflections of differing periodicity are found to return from both the mine and the ground. The presence of these specular reflections offers a potential alternative method of determining a mine’s presence.

A comprehensive review of the environmental impacts and human health risks associated with the occurrence of waste pharmaceuticals in water sources of the United States, and policy implications

The occurrence of waste pharmaceuticals has been identified and well documented in water sources throughout North America and Europe. Many studies have been conducted which identify the occurrence of various pharmaceutical compounds in these waters. This project is an extensive review of the documented evidence of this occurrence published in the scientific literature. This review was performed to determine if this occurrence has a significant impact on the environment and public health. This project and review found that pharmaceuticals such as sex hormone drugs, antibiotic drugs and antineoplastic/cytostatic agents as well as their metabolites have been found to occur in water sources throughout the United States at levels high enough to have noticeable impacts on human health and the environment. It was determined that the primary sources of this occurrence of pharmaceuticals were waste water effluent and solid wastes from sewage treatment plants, pharmaceutical manufacturing plants, healthcare and biomedical research facilities, as well as runoff from veterinary medicine applications (including aquaculture). ^ In addition, current public policies of US governmental agencies such as the Environmental Protection Agency (EPA), Food and Drug Administration (FDA), and Drug Enforcement Agency (DEA) have been evaluated to see if they are doing a sufficient job at controlling this issue. Specific recommendations for developing these EPA, FDA, and DEA policies have been made to mitigate, prevent, or eliminate this issue.^ Other possible interventions such as implementing engineering controls were also evaluated in order to mitigate, prevent and eliminate this issue. These engineering controls include implementing improved current treatment technologies such as the advancement and improvement of waste water treatment processes utilized by conventional sewage treatment and pharmaceutical manufacturing plants. In addition, administrative controls such as the use of “green chemistry” in drug synthesis and design were also explored and evaluated as possible alternatives to mitigate, prevent, or eliminate this issue. Specific recommendations for incorporating these engineering and administrative controls into the applicable EPA, FDA, and DEA policies have also been made.^

First steps in the discovery of patterns in the academic results of telecommunication engineering students in the subjects Analysis of Circuits and Mathematics

In this paper, the results of six years of research in engineering education, in the application of the European Higher Education Area (EHEA) to improve the performance of the students in the subject Analysis of Circuits of Telecommunication Engineering, are analysed taking into consideration the fact that there would be hidden variables that both separate students into subgroups and show the connection among several basic subjects such as Analysis of Circuits (AC) and Mathematics (Math). The discovery of these variables would help us to explain the characteristics of the students through the teaching and learning methodology, and would show that there are some characteristics that instructors do not take into account but that are of paramount importance

A model for evaluation of generic competences in engineering: application to the problem-solving competence at UPM.

The competence evaluation promoted by the European High Education Area entails a very important methodological change that requires guiding support to help teachers carry out this new and complex task. In this regard, the Technical University of Madrid (UPM, by its Spanish acronym) has financed a series of coordinated projects with a two-fold objective: a) To develop a model for teaching and evaluating core competences that is useful and easily applicable to its different degrees, and b) to provide support to teachers by creating an area within the Website for Educational Innovation where they can search for information on the model corresponding to each core competence approved by UPM. Information available on each competence includes its definition, the formulation of indicators providing evidence on the level of acquisition, the recommended teaching and evaluation methodology, examples of evaluation rules for the different levels of competence acquisition, and descriptions of best practices. These best practices correspond to pilot tests applied to several of the academic subjects conducted at UPM in order to validate the model. This work describes the general procedure that was used and presents the model developed specifically for the problem-solving competence. Some of the pilot experiences are also summarised and their results analysed

Considerations on the success rate in aeronautical engineering studies in Spain

The relationship between different learning evaluation methods and the academic success in an aeronautical engineering degree in Spain is analysed. The study is based on data about the evolution of academic achievement obtained along the last ten year, along which the evaluation and learning’s methods have suffered huge changes.

Translational research combining orthologous genes and human diseases with the OGOLOD dataset

OGOLOD is a Linked Open Data dataset derived from different biomedical resources by an automated pipeline, using a tailored ontology as a scaffold. The key contribution of OGOLOD is that it links, in new RDF triples, genetic human diseases and orthologous genes, paving the way for a more efficient translational biomedical research exploiting the Linked Open Data cloud.