Bibliography: leaves 197-220. / xv, 220 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Analyses some general problems of laparoscopy, particularly in relation to induced physiological disturbances; by development and evaluation of new applications in laparoscopic gastrointestinal surgery ; and by assessing the efficacy of laparoscopic procedures which have already entered rountine practice. / Thesis (M.D.)--University of Adelaide, Dept. of Surgery, 1996?

Close integration of front-end electronics and the transducer array within the catheter is critical for successful implementation of CMUT-based intravascular ultrasound (IVUS) imaging catheters to enable next generation imaging tools. Therefore, this research developed and implemented custom-designed electronic circuits and systems integrated with an IC compatible transducer technology for realization of miniature IVUS imaging catheters operating at 10-50 MHz frequency range. In one path of this research, an IC is custom designed in a 0.35-um CMOS process to monolithically integrate with a CMUT array (CMUT-on-CMOS) to realize a single-chip, highly-flexible, forward-looking (FL) IVUS imaging system. The amplifiers that are custom-designed achieved transducer thermal-mechanical noise dominated receive performance in a CMUT-on-CMOS implementation. In parallel to the FL-IVUS effort, for realization of a side-looking IVUS catheter based on an annular phased array, a dynamic receive beamformer IC is custom designed also in a 0.35-um CMOS process. Overall, the circuits and systems developed as part of this dissertation form a critical step in the translation of the research on CMUT-based IVUS catheters into real clinical applications for better management of coronary arterial diseases.

The invention of medical imaging technology revolved the process of diagnosing diseases and opened a new world for better studying inside of the human body. In order to capture images from different human organs, different devices have been developed. Gastro-Endoscopy is an example of a medical imaging device which captures images from human gastrointestinal. With the advancement of technology, the issues regarding such devices started to get rectified. For example, with the invention of swallow-able pill photographer which is called Wireless Capsule Endoscopy (WCE); pain, time, and bleeding risk for patients are radically decreased. The development of such technologies and devices has been increased and the demands for instruments providing better performance are grown along the time. In case ofWCE, the special feature requirements such as a small size (as small as an ordinary pill) and wireless transmission of the captured images dictate restrictions in power consumption and area usage. In this research, the reduction of image encoder hardware cost for endoscopic imaging application has been focused. Several encoding algorithms have been studied and the comparative results are discussed. An efficient data encoder based on Lempel-Ziv-Welch (LZW) algorithm is presented. The encoder is a library-based one where the size of library can be modified by the user, and hence, the output data rate can be controlled according to the bandwidth requirement. The simulation is carried out with several endoscopic images and the results show that a minimum compression ratio of 92.5 % can be achieved with a minimum reconstruction quality of 30 dB. The hardware architecture and implementation result in Field-Programmable Gate Array (FPGA) for the proposed window-based LZW are also presented. A new lossy LZW algorithm is proposed and implemented in FPGA which provides promising results for such an application.

The invention of medical imaging technology revolved the process of diagnosing diseases and opened a new world for better studying inside of the human body. In order to capture images from different human organs, different devices have been developed. Gastro-Endoscopy is an example of a medical imaging device which captures images from human gastrointestinal. With the advancement of technology, the issues regarding such devices started to get rectified. For example, with the invention of swallow-able pill photographer which is called Wireless Capsule Endoscopy (WCE); pain, time, and bleeding risk for patients are radically decreased. The development of such technologies and devices has been increased and the demands for instruments providing better performance are grown along the time. In case ofWCE, the special feature requirements such as a small size (as small as an ordinary pill) and wireless transmission of the captured images dictate restrictions in power consumption and area usage. In this research, the reduction of image encoder hardware cost for endoscopic imaging application has been focused. Several encoding algorithms have been studied and the comparative results are discussed. An efficient data encoder based on Lempel-Ziv-Welch (LZW) algorithm is presented. The encoder is a library-based one where the size of library can be modified by the user, and hence, the output data rate can be controlled according to the bandwidth requirement. The simulation is carried out with several endoscopic images and the results show that a minimum compression ratio of 92.5 % can be achieved with a minimum reconstruction quality of 30 dB. The hardware architecture and implementation result in Field-Programmable Gate Array (FPGA) for the proposed window-based LZW are also presented. A new lossy LZW algorithm is proposed and implemented in FPGA which provides promising results for such an application.

Micro-Electro-Mechanical Systems (MEMS) micromirrors have been developed for more than two decades along with the development of MEMS technology. They have been used into many application fields: optical switches, digital light projector (DLP), adoptive optics (AO), high definition (HD) display, barcode reader, endoscopic optical coherence tomography (OCT) and confocal microscope, and so on. Especially, MEMS mirrors applied into endoscopic OCT and confocal microscope are the intensive research field. Various actuation mechanisms, such as electrostatic, electromagnetic, electro bimorph thermal, electrowetting, piezoelectric (PZT) and hybrid actuators, are adopted by different types of micromirrors. Among these actuators, the electrostatic is easily understood and simple to realize, therefore, it is broadly adopted by a large number of micromirrors. This thesis reports the design, fabrication, and characterization of a 2-D Silicon-on-insulation (SOI) MEMS micromirror with sidewall (SW) electrodes for endoscopic OCT or confocal microscope imaging. The biaxial MEMS mirror with SW electrodes is actuated by electrostatic actuators. The dimension of mirror plate is 1000micron×1000micron, with a thickness of a 35micron. The analytical modeling of SW electrodes, fabrication process, and performance characteristics are described. In comparison to traditional electrostatic actuators, parallel-plate and comb-drive, SW electrodes combined with bottom electrodes achieve a large tilt angle under a low drive voltage that the comb-drive does and possess fairly simple fabrication process same as that of the parallel-plate. A new fabrication process based on SOI wafer, hybrid bulk/surface micromachined technology, and a high-aspect-ratio shadow mask is presented. Moreover, the fabrication process is successfully extended to fabricate 2×2 and 4×4 micromirror arrays. Finally, a biaxial MEMS mirror with SW electrodes was used into Confocal MACROscope for imaging. Studied optical requirements in terms of two optical configurations and frequency optimization of the micromirror, the biaxial MEMS mirror replaces the galvo-scanner and improves the MACROscope. Meanwhile, a new Micromirror-based Laser Scanning Microscope system is presented and allows 2D images to be acquired and displayed.

published_or_final_version / Nursing Studies / Master / Master of Nursing

Aortic stenosis is a life-threatening valvular heart disease. At the onset of symptoms, a patient’s prognosis becomes poor and the risk of death rapidly increases. Aortic valve replacement surgery remains the gold standard in treatment for aortic stenosis. However, in the total population of patients with severe aortic stenosis, about one third are deemed inoperable due to their high surgical risk. In recent years, the development of transcatheter aortic valve implantation (TAVI), a non-invasive heart valve replacement procedure brought hope for the elderly, high-risk and inoperable aortic stenosis patient population pool. A literature review was performed to examine the safety, efficacy and effectiveness evidence for transcatheter aortic valve treatment option. The results showed that TAVI is a safe treatment option, however the effectiveness for the whole patient population is unknown. The adoption of this alternative treatment option is certainly coupled with multiple dimension of impact from a public health perspective. It remains inconclusive whether TAVI is an effective treatment option to be adopted. / published_or_final_version / Public Health / Master / Master of Public Health

Diagnosis of acute pancreatitis (AP) is erroneous in up to one third of patients when based on clinical criteria and elevated serum amylase values. Furthermore, according to autopsy reports fatal pancreatitis remains clinically undiagnosed in 22 to 86 % of hospitalised patients. Consequently, search for better methods for the diagnosis of AP seems not only justified but urgent. The pancreas secretes an nonspecific lipase, the carboxylic ester hydrolase (CEH) with molecular properties different from other pancreatic secretory enzymes. These differences may imply that sites and rates of clearances from blood of pancreatic enzymes differ. Except for the pancreas this enzyme is secreted from the lactating mammary gland with milk. A sensitive and reproducible sandwich-ELISA for quantitative determination of CEH was developed. When establishing referent values it was noted that in individuals aged 20 to 65 years serum concentrations of CEH did not depend on age, gender, the time of the day or duration from food intake to blood sampling, or use of nicotine. The mammary gland did not contribute significantly to basal serum levels of CEH; enzyme levels in lactating women or women with mammary tumours were identical to those of the reference population. Seventy percent of patients with the diagnosis AP, based on elevated serum amylase levels and abdominal pain, had elevated CEH values. Among the patients with elevated amylase alone a probable cause of pancreatitis was lacking in the majority of patients. Contrastingly, a likely cause of AP could be identified in all patients presenting with abdominal pain and elevated CEH levels alone. These findings suggested that an elevated CEH level indicated AP more reliably than an elevated amylase level. In patients with AP diagnosed by contrast enhanced computed tomography (CECT) alone, or combined with histopathological diagnosis, serum CEH levels were elevated on admission in all but one patient, and in all within the next 24 h. Furthermore, in patients with severe pancreatitis CEH levels remained at a raised level from the second to at least the 10:th day following admission, whereas a significant decrease was noted in patients with mild pancreatitis. In contrast, serum amylase values were higher in patients with mild pancreatitis during the observation period than in those with severe pancreatitis. CEH levels were higher in patients with three or more Ranson signs than in those with less than three signs from the first day after admission. CEH levels were within referent range in 164 patients without known pancreatic disease admitted due to abdominal emergency conditions, or due to planned surgery for chronic extrapancreatic gastrointestinal diseases, and 16 patients having CECT without pathological findings in the pancreas. This suggests that AP can be excluded with very high degree of probability in presence of non-elevated CEH levels. A sandwich ELISA for determination of Guinea pig CEH and a model for graded pancreatitis in the same species were developed. CEH levels showed proportional to severity of inflammation, thus confirming previous clinical observations. CEH levels in bile were proportional to inflammation, while it was absent in urine. Amylase levels in urine were identical regardless of severity of inflammation, but low in bile. These results suggested differences in sites and rates of clearance between the two enzymes. Seemingly elevated CEH levels allowed identification of clinically significant pancreatitis following ERCP, which amylase levels did not. The presented studies have shown that quantitative determination in serum of CEH by the described method is a more reliable test for the diagnosis of AP than determination of amylase activity. The differences between CEH and amylase are, at least partly, due to differences in molecular properties determining rates and routes of clearances of the two enzymes from serum. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1994, härtill 5 uppsatser.</p> / digitalisering@umu.se

Micro-Electro-Mechanical Systems (MEMS) micromirrors have been developed for more than two decades along with the development of MEMS technology. They have been used into many application fields: optical switches, digital light projector (DLP), adoptive optics (AO), high definition (HD) display, barcode reader, endoscopic optical coherence tomography (OCT) and confocal microscope, and so on. Especially, MEMS mirrors applied into endoscopic OCT and confocal microscope are the intensive research field. Various actuation mechanisms, such as electrostatic, electromagnetic, electro bimorph thermal, electrowetting, piezoelectric (PZT) and hybrid actuators, are adopted by different types of micromirrors. Among these actuators, the electrostatic is easily understood and simple to realize, therefore, it is broadly adopted by a large number of micromirrors. This thesis reports the design, fabrication, and characterization of a 2-D Silicon-on-insulation (SOI) MEMS micromirror with sidewall (SW) electrodes for endoscopic OCT or confocal microscope imaging. The biaxial MEMS mirror with SW electrodes is actuated by electrostatic actuators. The dimension of mirror plate is 1000micron×1000micron, with a thickness of a 35micron. The analytical modeling of SW electrodes, fabrication process, and performance characteristics are described. In comparison to traditional electrostatic actuators, parallel-plate and comb-drive, SW electrodes combined with bottom electrodes achieve a large tilt angle under a low drive voltage that the comb-drive does and possess fairly simple fabrication process same as that of the parallel-plate. A new fabrication process based on SOI wafer, hybrid bulk/surface micromachined technology, and a high-aspect-ratio shadow mask is presented. Moreover, the fabrication process is successfully extended to fabricate 2×2 and 4×4 micromirror arrays. Finally, a biaxial MEMS mirror with SW electrodes was used into Confocal MACROscope for imaging. Studied optical requirements in terms of two optical configurations and frequency optimization of the micromirror, the biaxial MEMS mirror replaces the galvo-scanner and improves the MACROscope. Meanwhile, a new Micromirror-based Laser Scanning Microscope system is presented and allows 2D images to be acquired and displayed.

Obstetric trauma is a major cause of faecal incontinence in women resulting in considerable social disability. Until recently the development of faecal incontinence has been attributed largely to damage to the pelvic nerves. However the advent of anal endosonography has added a new dimension to our understanding of the pathophysiology of faecal incontinence. In this thesis, gross dissection and histological studies of 19 anorectal specimens was performed to demonstrate the normal anatomy. Simultaneous dissection and sonography of the anorectum (14 in vivo and 12 in vitro studies) has clarified the normal sonographic anatomy of the anal sphincters. Anal endosonography was performed in 114 healthy volunteers to demonstrate gender differences in anal sphincter anatomy. A prospective study of 12 patients undergoing secondary sphincter repair and 15 patients undergoing lateral internal anal sphincterotomy has validated the appearance of sonographic sphincter defects. A new technique of demonstrating the anal sphincters at rest using vaginal endosonography has been demonstrated in 20 women. A prospective study of 202 pregnant women using anal endosonography and neurophysiological tests has demonstrated that 35% of primigravidae (13% symptomatic) and 44% of multigravidae (23% symptomatic) develop occult anal sphincter defects during vaginal delivery. Although pudendal nerve damage can be identified in 16% of women 6 weeks after delivery, in the majority this recovers with time. Forceps delivery was identified as the single independent variable associated with sphincter damage although damage was also sustained in the absence of instrumental delivery. In a separate study of 50 women who sustained a recognized third degree tear 47% were found to be symptomatic despite a primary sphincter repair. In 85% of these women persistent anal sphincter defects were identified sonographically. In a further study of 43 women who had an instrumental delivery (17 vacuum and 26 forceps) anal sphincter defects were identified in 81% (38% symptomatic) of women who were delivered by forceps compared to 12% (21% symptomatic) delivered by the vacuum extractor. One hundred and fifty doctors and midwives were interviewed to assess their knowledge and training in perineal anatomy and repair. There was a clear deficiency in knowledge and inconsistencies in classification of third degree tears were apparent highlighting the need for more focused training in perineal anatomy and repair. / Thesis (Ph.D.)-University of Natal, 1994.