Researchers have long been interested in the role of the corpus callosum in reading disorder, but existing studies have yielded inconsistent results. Some have found larger corpus callosa in those with reading disorder, others have found smaller corpus callosa, and some have found no differences in the corpus callosa of persons with and without reading disability. Some possible problems with past studies include failure to control for whole brain size, intelligence, gender, lateral dominance, and the presence of other syndromes such as Attention Deficit Hyperactivity Disorder. The current study is an examination of the corpus callosum in 68 readers nested in 24 families. Data were centered around the family mean so that the variance within families could be determined. Corpus callosum volumes were measured and controlled for whole brain volume, intelligence, and gender. A series of regressions were used to determine whether the volume of the corpus callosum significantly contributed to the variance in oral reading, phonological processing, and rapid naming. The midsagittal slice was segmented into fifths, and similar regressions were performed. A logistic regression was used to determine whether variation in corpus callosum volume could predict RD and no RD group membership. Finally, left and right volumes were compared and a correlation between corpus callosum volume and area at the midsagittal slice were conducted. Results suggest that better readers within families have larger corpus callosum areas in the midsagittal slice at the midbody. Better phonological processors within families had smaller corpus callosum volumes, but a problem with restricted range for phonological processing scores renders this finding unreliable. Rapid naming scores appear to be unrelated to the corpus callosum in this sample. Differences in the corpus callosum are not robust enough to predict diagnostic group and there appears to be no differences between left and right hemisphere volumes of the corpus callosum. Measurements of area at the midsagittal slice are highly correlated with the volumetric measurements suggesting that for subsequent studies, area at the midsagittal slice may be sufficient. / text

MRI-guided prostate needle biopsy requires compensation for organ motion between target planning and needle placement. Two questions are studied and answered in this work: is rigid registration sufficient in tracking the targets with a maximum error of 3 mm (smaller than average prostate tumor size) and how many intra-operative slices are required to obtain this accuracy? We developed rigid and deformable multislice- to-volume registration algorithms for tracking the biopsy targets within the prostate. Three orthogonal plus additional transverse intra-operative slices were acquired in the approximate center of the prostate and registered with a high-resolution target planning volume. Simulated intra-operative data, phantom data, and MRI-guided robotic prostate biopsy data were used to assess tracking accuracy. Registration tests on simulated intra-operative data with 3, 4, and 5 slices were performed to evaluate the effect on registration error and time. Results: Using three orthogonal slices pro- vides sufficient accuracy. Convergence test results on phantom images demonstrated 100% success rate for initial misalignment of 5mm. Average registration errors for the patient data were 2.55mm and 2.05mm for the rigid and deformable algorithms, respectively. The algorithm was able to capture rigid biopsy target displacements of maximum 8mm and non-rigid displacements of maximum 1.5mm. Rigid tracking appears to be promising. Deformable registration does not seem warranted. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2010-07-13 16:41:52.223

Chronic intermittent ethanol exposure (CIE) is associated with degeneration of hippocampal neurons. The present study used hippocampal cultures to examine the loss of NeuN immunoreactivity, a relaible marker or neuronal density, after 1, 2, or 3 cycles of 5 days EtOH exposure (50 mM), followed by a 24-hour period of EWD or continuous EtOH exposure. NeuN immunoreactivity was decreased by 13%, 19%, and 16% in the CA1, CA3, and dentate gyrus after 3 cycles of CIE respectively; thionine staining confirmed significant cellular losses within each hippocampal subregion. Two cycles of CIE in aged tissue cultures resulted in significant decreases in NeuN immunoreactivity in all hippocampal subregions; however continuous ethanol exposure or exposure to one cycle of CIE did not. Further, exposure to the N-Methyl-D-aspartate receptor (NMDAR) antagonist 2-amino-7-phosphonvaleric acid (APV) (30 uM) during periods of EWD attenuated the loss of NeuN in all hippocampal subregions, while exposure to APV (40 uM) prevented the loss of NeuN in the CA1 and dentate gyrus. These results suggest that the loss of mature neurons after CIE is associated with the overactivation on the NMDAR.

The goal of the present study was to develop and compare two different methods for rating scaffolding between siblings: a thin slice approach and an interval coding approach. Fifty younger (age=3 years) and 50 older (age 3-7 years) siblings interacted for five minutes on a cooperation task and scaffolding during the task was coded for each child. Internal consistency was excellent for the thin slice measure and questionable for the interval measure. Inter-rater reliability was good for both. Thin-slicing was more strongly related to predicted variables (children’s theory of mind, language, age, cooperation, positive and negative behavior) than interval coding, and reduces demands on resources in terms of training and reliability. The development of a reliable and valid measurement for the assessment of child-to-child scaffolding, which involves limited training and is quick to code, will be a useful research and practice tool for developing children’s cooperation skills in applied settings.

The goal of the present study was to develop and compare two different methods for rating scaffolding between siblings: a thin slice approach and an interval coding approach. Fifty younger (age=3 years) and 50 older (age 3-7 years) siblings interacted for five minutes on a cooperation task and scaffolding during the task was coded for each child. Internal consistency was excellent for the thin slice measure and questionable for the interval measure. Inter-rater reliability was good for both. Thin-slicing was more strongly related to predicted variables (children’s theory of mind, language, age, cooperation, positive and negative behavior) than interval coding, and reduces demands on resources in terms of training and reliability. The development of a reliable and valid measurement for the assessment of child-to-child scaffolding, which involves limited training and is quick to code, will be a useful research and practice tool for developing children’s cooperation skills in applied settings.

No description available.

Hepatobiliary disease can sometimes be difficult to diagnosis due to non-specific clinical signs, and diagnostic imaging is a vital tool in diagnosing these diseases. Multi-slice computed tomographic cholangiography (MSCTC) is a non-invasive way to obtain high quality images of the hepatobiliary system. Our objectives were to determine the best technique for performing MSCTC in normal dogs with regards to contrast agent, dose, and optimal time to imaging. Our test subjects included eight normal adult hounds. Four dogs were administered Cholografin and the other four Biliscopin. Two dose groups were established with four dogs receiving 0.5mL/kg and four receiving 1 mL/kg. Our results demonstrated that MSCTC is feasible in normal dogs and produces high quality images of the hepatobiliary system. The contrast agent Biliscopin at the higher dose subjectively produced the best quality images. The optimal time to image patients following contrast administration varied between contrast agents (15-60 minutes).

<p>Structural walls in existing buildings designed to pre 1970s codes may have deficient shear reinforcement and lap splice detailing. Lap splices at the bottom of the walls were designed in compression with anchorage length of 24-bar diameter. When the structural wall is subjected to lateral loads during a major seismic event, the lap splice is in the zone of maximum moment and shear and may be subjected to tension. Such design may cause nonductile behaviour and sudden failure of the wall due to shear or bond slip of the lap splice reinforcing bars. The effect of shear and ductility rehabilitation on the behaviour of reinforced concrete structural walls, without lap splice, have shown improvement in the structural wall shear resistance and ductility and hence overall structural ductility and seismic loads resistance. Research on rehabilitation of reinforced concrete (RC) structural walls with both deficient shear reinforcement and lap splice detailing is still needed. </p> <p> The principal objectives of this study were to evaluate the seismic behaviour of non-ductile reinforced concrete structural walls before and after rehabilitation using carbon fibre reinforced polymers (CFRP). These objectives were achieved through experimental and analytical investigations.</p> <p> The experimental phase of this research involved testing large scale models of RC structural walls with deficient shear strength and lap splice detailing to reproduce failure modes observed following major seismic events and to evaluate the rehabilitation schemes. Ten RC structural walls were built and tested under cyclic loading. Three control walls were tested as-built with non-ductile detailing and seven walls were rehabilitated before testing. The purpose of the rehabilitation techniques was to prevent brittle failure in shear or bond slip and to improve the ductility and energy dissipation of RC structural walls.</p> <p> The analytical phase of this study involved evaluation of the inelastic dynamic response of RC residential building with nonductile structural walls as well as retrofitted walls. An efficient macroscopic model to represent the behaviour of RC structural walls when subjected to pushover, cyclic and dynamic seismic loads was developed. The proposed model was intended to adequately describe the hysteretic behaviour of walls and to be capable of accurately predicting both flexural and shear components of inelastic deformation. The model predictions were compared with the experimental results. The comparisons showed that the developed analytical model predicted the inelastic walls response with a good accuracy. The analytical model was capable to evaluate the nonlinear dynamic behaviour of an existing building under seismic excitation before and after rehabilitation.</p> / Thesis / Doctor of Philosophy (PhD)

<p> In the past, analog circuits, discrete digital logic circuits or minicomputers have been used to implement the signal processing section of a sonar systems. More recently, microprocessor based logic circuit designs have produced a new breed of system design approach which gives designers the flexibility that has never been available through the use of analog or discrete logic circuits; however, due to the inherent slow speed of the metal-oxide semiconductor (MOS) logic circuits, incorporating microprocessors in the implementation of a sonar signal processor is not feasible. With the advent of bipolar Schottky large scale integrated circuit technology, the speed performance of the microprocessors have been improved considerably, and signal processor designs employing microprocessors are now feasible. </p> <p> The main objective of this work is to design, implement, and test a real-time digital sonar signal processor for processing pulsed CW signals. With design based on the use of the bit slice microprocessor, a signal processor has been constructed that has an 8 bit input, a 16 bit output. The processor is capable of detecting 16 different Doppler shifts. Laboratory generated signals are used in the testing and the experimental results show good agreement with the theory. A possible means of expanding the existing single channel signal processor into a multichannel processor has also been outlined. </p> / Thesis / Master of Engineering (MEngr)

No description available.