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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

Parents, watching: introducing surveillance into modern American parenting

Howell, James Perry 01 December 2010 (has links)
During the last quarter of the twentieth century, there has been a significant expansion in the means by which parents in the United States might use technologies to watch their children. Watching and worrying about children are not new to the job of parenthood, but the ways of watching now available to parents represents a change of degree so great as to represent a change in kind. The parental gaze has become technologized. This dissertation investigates what happens when man-made devices insert themselves into this most basic of human endeavors. Parenting desires, social expectations, and technological capacities have co-evolved in the United States to a point where the norms of parental watching are increasingly technology-based. This is a "mixed methods," cross-case study. It delves into the particulars of three distinct media while looking for patterns of use and effects across the different technologies. The core of this investigation is three case studies of particular surveillance technologies that all came to prominence, in terms of their popularity or frequency of use, in the United States in the last thirty years. The three subjects of these case studies--fetal ultrasound, Eisenberg, Murkoff, and Hathaway's 1984 pregnancy advice and guide book What to Expect When You're Expecting, and baby monitors--are all media that offer parents the opportunity to be better and less anxious parents by enhancing their powers of parenting observation. They form an optical--textual--acoustic triad that demonstrates the breadth of media that are enlisted into surveillance practices. These new anxiety technologies change thinking, perceptions, and attitudes. They serve both to introduce new human capacities and to direct and to mold existing capacities. They have also helped to change our ideas of what is possible. A few overarching characteristics of American parental thinking have helped to pushed surveillance to prominence. Middle class American parents of the last quarter of the twentieth century have come to feel that the world is a more dangerous place for their children. They perceive their offspring as more vulnerable to dangers and as less capable of avoiding these dangers on their own. Parents also feel an increased sense of personal responsibility for the safety of their children. It is not that that contemporary parents have warmer or deeper feelings toward their children, but rather that contemporary parents believe that they both can and should control a much broader range of dangers to their children than parents in the past believed they could control. The "anxiety technologies" of this study serve in part to bring home to their users the riskiness of parenting and the vulnerability of the fetus/infant. These technologies have come to promote responsibility expansion, efficiency orientation, and risk focus for parents. While these technologies do provide parents with a great deal more focused information, many of the perceived enhancements in powers to effect outcomes are presumptive, illusory effects of actual increases in information. Information without influence is as likely to contribute to anxiety as to power.
412

Effect of High Intensity Ultrasound on Crystallization Behavior and Functional Properties of Lipids

ye, Yubin 01 May 2015 (has links)
The effects of high intensity ultrasound (HIU) on the crystallization behavior and functional properties of shortenings were evaluated. HIU was applied to different shortenings such as interesterified soybean oil (IESBO), multi-purpose commercial shortening, palm oil, and palm stearin. The functional properties measured include crystal morphology, solid fat content, melting profile, viscoelastic properties, hardness, and polymorphism. Different experimental set-ups were evaluated including a static batch system, a temperature cycling design, and flow cell system. Results showed that HIU generated harder material on IESBO, commercial shortening, and palm oil with more uniform and smaller crystal size, sharper melting profile, and higher elasticity. No chemical changes on triacylglycerol (TAG) and fatty acids were observed on IESBO under the sonication conditions used in this dissertation. Application of HIU maintained the texture of the commercial shortening that was subjected to temperature fluctuations, especially when HIU was applied before changes in temperature occurred. When sonication was applied in a flow-cell system lower power levels applied in a continuous manner was proved to be the most effective at inducing crystallization of palm oil. Research also showed that pulse irradiation of sonication and higher flow rates could be used to decrease the thermal effects generated by higher power levels of HIU. In addition, HIU was used in a highly saturated fat (palm stearin) at low power levels with long durations to delay lipid crystallization and generate a softer material. All the research findings suggest the great potential use of HIU in shortening production and food processing to improve the texture and its stability, as well as other functional properties.
413

Development and Implementation of a DSP Based Air Detector System to Prevent Embolism During Hemodialysis Therapy

Nguyen, Nhat 04 November 2005 (has links)
This thesis describes the design of a DSP based air detector system to prevent air embolism during Hemodialysis, which is a treatment option for kidney failure disease. Hemodialysis consists of removing blood from the body, filtering and treating the blood to remove toxic substances such as wastes and fluids, reestablishing proper chemical levels in the blood and returning the processed blood to the body. The functions of hemodialysis are performed through the use of a dialyzer, which is also known as an artificial kidney. During hemodialysis small air bubbles may infiltrate the tubing used during the therapy and combine to form larger air bubbles that are harmful to the patient. If an air bubble is large enough and enters the patient's circulatory system, the blood flow can be blocked and the patient can die by embolism. Most of the hemodialysis instruments in use today are equipped with air detection systems, which are based on analog design and digital microcontroll ers. This thesis presents a design method based strictly on DSP technology. The Motorola DSP 56824EVM was considered suitable for this biomedical application since its performance parameters include high-speed, multi-signal control capability, reliability and stability. These performance parameters are considered to be the most important when designing biomedical instruments dealing with human beings' life and safety. The objective of this research was the development and implementation of a DSP algorithm for the detection and measurement of the sizes of air bubbles in a fluid. In addition the algorithm had to possess the capability, when appropriate, to initiate protective and awareness measures such as triggering a tube clamp as well as activating visual and audio alarms. The air detection was accomplished by means of a commercial air detector module, which was based on piezo ceramic and ultrasound sensing. The function of the tubing clamp was to stop the fluid flow in the tubing and prevent an air bubble from entering the patient's circulatory system. A secondary goal of this research was to exploit the capability of the DSP 56824EVM and demonstrate its suitability for biomedical applications.
414

Ultrasound imaging of finger tendons at the bedside in the emergency department: a pilot study to assess whether it is a feasible and useful investigation

Hall, Ann Charlotte Unknown Date (has links)
The interplay of structures in the finger that facilitate movement is complex and not yet fully understood. Subtle finger injuries are often missed during the initial assessment in the Emergency Department, because clinical examination of the acutely injured hand can be difficult. The consequences of unrecognized finger injuries can be devastating for the patient. Ultrasound imaging of tendons is a useful investigative tool although little has been published regarding the reliability of finger tendon measurements. The overall objective of this project was to establish if bedside ultrasound imaging of tendons was possible and useful in the setting of acute injury. The project was divided into two studies.In the first study, 65 apparently normal volunteers were scanned to allow the principal investigator to practise and refine the ultrasound technique. The dimensions of the Extensor Digitorum Longus and two flexor tendons combined (Flexor Digitorum Profundus and Flexor Digitorum Superficialis) were measured in both transverse and longitudinal sections. Fifteen of the volunteers had their left middle fingers scanned twice within 48 hours to establish the test to retest reliability of tendon measurement. The established scanning technique was simple to perform and the scans, including both static and real time images, were completed within five minutes. All volunteers were able to tolerate a full scan. Measurement of tendon width showed fair to good reliability (Intra class correlation [ICC] of flexor tendons = 0.66, ICC of extensor tendon = 0.54). However measurement of the depth of all the tendons was unreliable test to retest (ICC < 0.37).In the second study, 30 patients who presented to the Emergency Department at Lismore Base Hospital with hand injuries were scanned for evidence of tendon injury and tendon gliding restriction. The patient’s ability to tolerate ultrasound examination was investigated. The scan findings were compared with the clinical findings and then to the operation report or to the patient’s self reported outcome, one month after injury.Patients were willing to undergo ultrasound examination regardless of the extent of their injury. There was a significant difference (p = 0.04) in scan tolerance related to the site of injury with 50% of those with extensor surface injuries having completed scans in comparison to 36% with flexor surface injuries and 9.1% of finger tip injuries. Injury mechanism was not related to scan tolerance.Excluding a partial tendon laceration was technically difficult due to the presence of anisotropy artefact. However, all complete tendon lacerations were successfully identified prior to surgery. The gliding of the tendons was easy to visualize and abnormal gliding was found to be a marker of tendon injury.The overall results show that ultrasound imaging of finger tendons at the bedside in the Emergency Department is a feasible examination to perform. The addition of ultrasound examination, however, did not identify any cases of tendon injury not already suspected on routine clinical examination.Therefore, this pilot study suggests that routine use of ultrasound examination to detect finger tendon injury in the Emergency Department setting will not prove to be a useful investigation. There may be a role for ultrasound as a screening tool as the gliding of normal tendons differed noticeably from the gliding of injured tendons. The presence of normal tendon gliding may be helpful in identifying those patients that are safe to be discharged from the Emergency Department without further evaluation.
415

Real-time DVR Illumination Methods for Ultrasound Data

Sundén, Erik January 2010 (has links)
<p>Ultrasound (US) volume data is noisy, so traditional methods for direct volume rendering (DVR) are less appropriate. Improved methods or new techniques are required. There are furthermore a high performance requirement and limited pre-processing to be considered in order for it to be used interactively, since the volume data might be time-varying.</p><p>There exist numerous techniques for improving visual perception of volume rendering, and while some perform well and produce a visually enhanced result, many are designed and compared for use with medical data that has a high signal-to-noise ratio. This master thesis describe and compare recent methods for DVR illumination, in the form of ambient occlusion or direct/indirect lighting from an external light source. New designs and modifications are introduced for efficiently and effectively enhancing the visual quality of DVR with US data. Furthermore, this thesis addresses the issue of how clipping is performed during rendering and for the different illumination techniques, which is commonly used in ultrasound visualization.</p><p>This diploma work was conducted at Siemens Corporate Research in Princeton, NJ where the partially open source framework XIP is developed. The framework was extended further to include modern methods for DVR illumination that are described in detail within this thesis. Finally, presented results show that several methods can be used to visually enhance the visualization within highly interactive frame-rates.</p>
416

Simulation Assisted Robotic Orthopedic Surgery in Femoroacetabular Impingement

Chang, Ta-Cheng 27 July 2011 (has links)
Femoroacetabular impingement (FAI) has been increasingly recognized as a cause of early hip osteoarthritis. FAI is characterized by pathologic contact between the femur and acetabular rim during hip join movement, caused by morphological abnormalities. Arthroscopic technique has become increasingly popular for FAI surgical treatment because of its minimal invasiveness. However, it involves cumbersome procedures and over- or under-resection are likely to occur. To tackle this issue, robot-assisted FAI arthroscopy is a well suited approach because it results in high accuracy and reproducible surgical outcomes. This dissertation provides new approaches and methods for the current challenges in the development of robot-assisted FAI arthroscopy. The study has three objectives: 1) to develop a robust calibration method for the A-mode ultrasound probe used for noninvasive bone registration, 2) to develop a bone registration simulator for verifying the registration accuracy and consistency for any given registration point-pattern, and 3) to develop a hip range of motion simulation system that returns the virtual range of motion and determines the bone resection volume. Carefully designed calibration procedures and simulation experiments have been conducted during the study of this research. From the experimental results, the developed ultrasound calibration method successfully reduces the registration errors and is proved to be robust. The results from the registration simulator indicate that the pattern with widely distributed points lead to better registration accuracy and consistency. The hip range of motion simulation system results in acceptable accuracy and successfully generates the resection volume. With further modifications, the ultrasound probe can be successfully calibrated with the developed method, and will be applied for noninvasive bone registration. The registration simulator can also be served as a useful tool for determining the optimized registration point-pattern, which can lead to reduced surgical trauma and registration time. Finally, the developed range of motion simulation system can allow the surgeon to evaluate the surgical outcome and to determine the resection volume even before the surgery begins. To conclude, this dissertation provides useful approaches, methods, and software for developing robot-assisted FAI arthroscopy.
417

Applications of TAP-NDE technique to non-contact ultrasonic inspection in tubulars

Baltazar-Lopez, Martin Eduardo 17 February 2005 (has links)
The possibility and feasibility of experimental detection of localized defects in tubes using laser-induced ultrasonic wave approach through Thermo Acousto Photonic Non Destructive Evaluation (TAP-NDE) and Signal processing through wavelet transform is examined in this research. Guided waves in cylindrical surfaces provide solutions for detection of different defects in the material. Several experiments were conducted to this respect. Wave propagation in both axial and circumferential directions was studied. The dispersive wave propagation of ultrasonic waves in hollow cylinders has been investigated experimentally, primarily for use in non-contact and nondestructive inspections of pipes and tubes. The laser ultrasonic waves propagated in cylindrical waveguides are particularly attractive because of their unique characteristics in the applications of nondestructive evaluation (NDE). Contrary to studies making use of only axially symmetric guided waves in hollow cylinders, here are analyzed also nonaxisymmetric waves. The analysis of data is made by using the Gabor wavelet transform. The capability of modeling the guided wave dispersion in hollow cylinders is used in developing guided wave experimental techniques for flaw detection. Good agreement was obtained when comparing the dispersion spectra between theory and experimentation. Measurement of group velocities of guided waves, which are obtained directly from the wavelet transform coefficients, can be used to determine allocation and sizing of flaws.
418

Tennis elbow : sonographic findings and intratendinous injection treatment

Zeisig, Eva January 2008 (has links)
Tennis elbow (TE) is a relatively common painful condition affecting the upper extremity. The aetiology is not known, but TE is most often seen in middle aged individuals using repetitive and forceful gripping at work or recreational activities, and is referred to overuse injuries. The pathogenesis is not known, but there are so-called degenerative changes in the wrist- and finger-extensor muscle origin (common extensor origin - CEO). The pain mechanisms involved have not been scientifically clarified. The studies in the present thesis aimed to 1) evaluate the structure and blood flow using ultrasound (US) and colour Doppler (CD) examinations of the CEO in patients with TE, and in pain-free elbows, 2) evaluate the clinical effects of US- and CD-guided intratendinous injection treatment with the sclerosing substance polidocanol, 3) evaluate the long term (2 years) effects of injection treatment on the tendon structure and blood flow, and 4) investigate if there is a local production of sympathetic and parasympathetic signal substances in non-neural cells in the CEO. Structural tendon changes and high blood flow was found in the CEO in patients with TE, but not in pain-free controls. Remaining structural changes and additional bone spur formation at the lateral epicondyle, but not high blood flow, were seen 2 years after successful injection treatment. In a randomised double-blind study, US- and CD-guided intratendinous injection treatment with sclerosing polidocanol or the local anaesthetic lidocaine combined with epinephrine, targeting the region with high blood flow, was found to reduce pain and increase grip strength in patients with TE. There were no differences in the outcome between the two treatment groups. A local production of catecholamines, but not acetylcholine, was found in fibroblasts in the CEO, in patients with TE. This thesis presents results showing US and CD examinations to be useful methods to diagnose TE, and to evaluate structure and blood flow in the CEO after treatment. US- and CD-guided injection treatment targeting high blood flow in the region with structural changes can reduce pain symptoms in patients with TE. The localised high blood flow, and local production of catecholamines in the tendon cells in the CEO, might be involved in the pain mechanisms.
419

Grout pump characteristics evaluated with the UVP+PD method

Rahman, Mashuqur, Håkansson, Ulf, Wiklund, Johan January 2012 (has links)
Rock grouting is performed to decrease the hydraulic conductivity around underground structures, such as tunnels and caverns. Cement grouts are often used and pumped into joint and fractures of the rock formation. Piston type pumps are mostly used for high pressure rock grouting. A pulsation effect is inevitable when using this type of pump due to the movement of the piston. The effect of this pulsation on rock grouting is yet to be known but believed to be benefi-cial for the penetration of the grout. Current flow meters used in the field are not accu-rate enough to determine the fluctuation of the flow rate when it is less than 1 l/min. In addition, currently available flow meters measure the average of the flow over a cer-tain period of time, hence the true fluctuation of the flow rate due to the pulsation of the piston remains unknown. In this paper, a new methodology, the so called ‘Ultrasound Velocity Profiling – Pressure Difference’ (UVP+PD) method has been introduced to show the pulsation effect when using a piston type pump. The feasibility of this method was successfully investigated for the direct in-line determination of the rheological properties of micro cement based grouts under field conditions (Rahman &amp; Håkansson, 2011). Subse-quently, it was also found that this method can be very efficient to measure the fluctu-ation of the flow rate for different types of pumps. From a grouting point of view the UVP+PD method can be used to synchronize the pressure and flow of a piston type pump by measuring the pulsation effect. Conse-quently it can be used as a tool for the efficiency and quality control of different types of pumps. / <p>QC 20121221</p>
420

3D follicle segmentation in ultrasound image volumes of ex-situ bovine ovaries

Lu, Qian 05 June 2008
Conventional ultrasonographic examination of the bovine ovary is based on a sequence of two-dimensional (2D) cross-section images. Day-to-day estimation of the number, size, shape and position of the ovarian follicles is one of the most important aspects of ovarian research. Computer-assisted follicle segmentation of ovarian volume can relieve physicians from the tedious manual detection of follicles, provide objective assessment of spatial relationships between the ovarian structures and therefore has the potential to improve accuracy. Modern segmentation procedures are performed on 2D images and the three-dimensional (3D) visualization of follicles is obtained from the reconstruction of a sequence of 2D segmented follicles. <p>The objective of this study was to develop a semi-automatic 3D follicle segmentation method based on seeded region growing. The 3D datasets were acquired from a sequence of 2D ultrasound images and the ovarian structures were segmented from the reconstructed ovarian volume in a single step. A seed is placed manually in each follicle and the growth of the seed is controlled by the algorithm using a combination of average grey-level, standard deviation of the intensity, newly-developed volumetric comparison test and a termination criterion. One important contribution of this algorithm is that it overcomes the boundary leakage problem of follicles of conventional 2D segmentation procedures. The results were validated against the aspiration volume of follicles, the manually detected follicles by an expert and an existing algorithm.<p>We anticipate that this algorithm will enhance follicular assessment based on current ultrasound techniques in cases when large numbers of follicles (e.g. ovarian superstimulation) obviate accurate counting and size measurement.

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