Yes / Complex biological tissues are highly viscoelastic and dynamic. Efforts to repair or replace cartilage, tendon, muscle, and vasculature using materials that facilitate repair and regeneration have been ongoing for decades. However, materials that possess the mechanical, chemical and resorption characteristics necessary to recapitulate these tissues have been difficult to mimic using synthetic resorbable biomaterials. Herein, we report a series of resorbable elastomer-like materials that are compositionally identical and possess varying ratios of cis:trans double bonds in the backbone. These features afford concomitant control over the mechanical and surface eroding degradation properties of these materials. We show the materials can be functionalized post-polymerization with bioactive species and enhance cell adhesion. Furthermore, an in vivo rat model demonstrates that degradation and resorption are dependent on succinate stoichiometry in the elastomers and the results show limited inflammation highlighting their potential for use in soft tissue regeneration and drug delivery.

Recovery of soft tissues, such as original cells, blood vessels, and proteinaceous fibers, from fossil bone is becoming more frequent, but the factors that control such exceptional preservation are not well understood. This study assesses the influence(s) exerted on soft tissue preservation by several possible controlling factors. Specifically, this study assesses biomechanical function, apatite recrystallization, bone tissue density, taxonomic identity, and depositional environment as possible controls on the quantity and quality of preservation of endogenous microstructures. Six bones derived from three taxa from the Paleogene White River Group of South Dakota and Nebraska – namely an oreodont from the Oligocene Brule Formation and a brontothere and tortoise from the Eocene Chadron Formation – were subsampled for cortical and trabecular bone, which were then assessed via demineralization, thin sectioning, transmitted light and scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). Bones belonging to each clade were acquired from bonebeds to minimize intraspecific variation in taphonomic history, and (where possible) similar skeletal elements were selected from each skeleton to similarly minimize differences in biomechanical function between corresponding samples. Initial demineralization analyses showed high yields of potentially endogenous cells and soft tissues in all three taxa: only two subsamples lacked structures morphologically consistent with osteocytes, and microstructures visually consistent with vertebrate blood vessels and fibrous matrix were recovered from all 12 subsamples pf the six fossils. Variation in the dominant tissue type corresponded with taxonomic identity and bone type and was independent of biomechanical function, as defined in this study, but this assertion requires a larger dataset to be conclusive. Apatite crystallinity loosely correlated with osteocyte preservation, but the association was less robust than the taxonomic identity. Transmitted light microscopy of histological thin sections revealed varying levels of histological alteration among the bones. SEM-EDS analyses of demineralized microstructures identified apparent zeolite mineralization and zeolite crystals within the majority of blood vessel fragments, although some examples of hollow vessels were found which were identified to be composed primarily of silicon, oxygen, and carbon. Elemental mapping of thin sections via SEM-EDS revealed evidence of double-medium diffusion through Haversian canals and trabecular voids, as well as a dominance of enlarged, recrystallized bioapatite crystals. Observed variations in thin section and SEM also suggest different taphonomic histories for the three clades, particularly the oreodont samples, as certain features observed in thin sections were not observed in SEM. The demineralization data indicate a potential correlation between taxonomic identity and soft tissue preservation, but geochemical and thin section analyses suggest geochemical processes controlling mineralization may have a greater influence on the abundance of microstructures recovered through demineralization assays. / Geology

A "Job Coach" model was developed based on sports medicine and rehabilitation principles for athletes, and individual placement and supported employment for people with psychiatric disabilities. This is a biopsychosocial model, emphasising workplace-based intervention. / Background. Occupational musculoskeletal soft tissue injuries represent a major source of work disability. There has been a gradual rise in the occurrence of occupational musculoskeletal injuries of the upper extremity, including both acute injuries and more chronic health problems. Return to work following an occupational injury is a multifactoral process, although traditional clinic-based rehabilitation programmes do not appreciate the importance of contextual factors. / Conclusion. Workplace work hardening programmes are a further development of work rehabilitation programmes. The therapeutic use of actual work facilities and the work environment can effectively facilitate the successful return to work process of the injured worker. More importantly, many of the psychosocial problems associated with separation from the work routine, peer group and/or the employer are minimised by the presence of the Job Coach. The results of this study confirm that workplace-based rehabilitation intervention is more effective than conventional clinic-based rehabilitation programmes in terms of prevention of further work disability, improvement in functional capabilities and decrease in perceived pain and disability. / Keywords. Job coach, workplace-based rehabilitation, rotator cuff injury, work disability, return to work intervention. / Methodology. A randomised controlled trial was conducted on 94 workers recruited from Workers' Compensation insurers. These workers had all sustained occupational rotator cuff injury and had lost more than 90 workdays. The workers were randomly assigned into control or experimental groups. The control group received a traditional work hardening programme and the experimental group received a workplace work hardening programme using the Job Coach model. The return to work outcomes of the two groups were compared. Areas of comparison included return to work rate after training, job retention ability and impact on earning capacity. Other outcome measures included change in active range of motion of the shoulder joint, eight basic functional capacities and the worker's perception of shoulder pain and disability based on the Shoulder Pain and Disability Index (SPADI). / Results. After one-month of the training programme, a higher return to work rate was obtained in the experimental group compared to the control group (71.4% against 37%, chi2=11.095, p=0.001). For job retention ability, 93.5% of the workers in the experimental group were still at work compared to 72.9% of workers in the control group (chi 2=7.031, p=0.008). No obvious salary change was noted between the two groups. / The SPADI was statistically significantly lower in the experimental group than in the control group (p=0.032), meaning that workers in the experimental group had fewer shoulder problems after training. Other significant improvements were noted in active shoulder flexion (p=0.001), arm lift strength (p=0.01), high-near lift strength (p=0.014), dynamic carrying strength (p=0.007) and overhead work tolerance (p=0.032), all of which were found to be statistically significantly higher in the experimental group than in the control group. / Cheng Shu-kei. / "July 2006." / Adviser: Leung Kim Hung. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1568. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 216-238). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Magister Scientiae Dentium - MSc(Dent) (Orthodontics) / Orthodontic treatment has the ability to improve the aesthetics and the function of patients. In order to create space, orthodontic treatment often requires removal of teeth. The most common teeth removed for orthodontic treatment are the premolars. It has become popular to remove second premolars in certain cases where the soft tissue profile should not be altered. The Damon self-ligating orthodontic system is renowned for not requiring dental extractions in the majority of cases. The effect of extractions on the soft tissue profile of patients, in conjunction with using the Damon system, has therefore not been researched. It is important to understand the effect that orthodontic treatment and extractions can have on the soft tissue profile of patients. This effect can accurately be determined by making use of the soft tissue cephalometric analysis, developed by Dr Reed A. Holdaway in 1983.

No description available.

BACKGROUND: The risk factors, microbial etiology, differentiation, and clinical features of purulent and non-purulent cellulitis are not well defined in Taiwan. METHODS: We conducted a retrospective cohort study of hospitalized adults with cellulitis in Taiwan in 2013. The demographic characteristics, underlying diseases, clinical manifestations, laboratory and microbiological findings, treatments, and outcomes were compared for patients with purulent and non-purulent cellulitis. RESULTS: Of the 465 patients, 369 had non-purulent cellulitis and 96 had purulent cellulitis. The non-purulent group was significantly older (p = 0.001) and was more likely to have lower limb involvement (p < 0.001), tinea pedis (p = 0.003), stasis dermatitis (p = 0.025), a higher Charlson comorbidity score (p = 0.03), and recurrence at 6 months post-infection (p = 0.001) than the purulent group. The purulent group was more likely to have a wound (p < 0.001) and a longer hospital stay (p = 0.001) and duration of antimicrobial therapy (p = 0.003) than the non-purulent group. The etiological agent was identified in 35.5 % of the non-purulent cases, with β-hemolytic streptococci the most frequent cause (70.2 %). The etiological agent was identified in 83.3 % of the purulent cases, with Staphylococcus aureus the predominant pathogen (60 %): 50 % of these were methicillin-resistant S. aureus (MRSA). In multivariable analysis, purulent group (odds ratio (OR), 5.188; 95 % confidence interval (CI), 1.995-13.493; p = 0.001) was a positive predictor of MRSA. The prescribed antimicrobial agents were significantly different between the purulent and non-purulent groups, with penicillin the most frequently used antimicrobial agent in the non-purulent group (35.2 %), and oxacillin the most frequent in the purulent group (39.6 %). The appropriate antimicrobial agent was more frequently prescribed in the non-purulent group than in the purulent group (83.2 % vs. 53.8 %, p < 0.001). CONCLUSIONS: The epidemiology, clinical features, and microbiology of purulent and non-purulent cellulitis were significantly different in hospitalized Taiwanese adults. Purulence was a positive predictor of MRSA as the causal agent of cellulitis. These findings provide added support for the adoption of the IDSA guidelines for empirical antimicrobial therapy of cellulitis in Taiwan.

This work presents an effective methodology for measuring the depth-resolved 3D full-field deformation of semitransparent, light scattering soft tissues such as vertebrate eye cornea. This was obtained by performing digital volume correlation on optical coherence tomography volume reconstructions of silicone rubber phantoms and porcine cornea samples. Both the strip tensile tests and the posterior inflation tests have been studied. Prior to these tests, noise effect and strain induced speckle decorrelation were first studied using experimental and simulation methods. The interpolation bias in the strain results has also been analyzed. Two effective approaches have been introduced to reduce the interpolation bias. To extract material constitutive parameters from the 3D full-field deformation measurements, the virtual fields method has been extended into 3D. Both manually defined virtual fields and the optimized piecewise virtual fields have been developed and compared with each other. Efforts have also been made in developing a method to correct the refraction induced distortions in the optical coherence tomography reconstructions. Tilt tests of different silicone rubber phantoms have been implemented to evaluate the performance of the refraction correction method in correcting the distorted reconstructions.

<p>Histopathology is the clinical standard for tissue diagnosis. However, histopathology has several limitations including that it requires tissue processing, which can take 30 minutes or more, and requires a highly trained pathologist to diagnose the tissue. Additionally, the diagnosis is qualitative, and the lack of quantitation leads to possible observer-specific diagnosis. Taken together, it is difficult to diagnose tissue at the point of care using histopathology.</p><p>Several clinical situations could benefit from more rapid and automated histological processing, which could reduce the time and the number of steps required between obtaining a fresh tissue specimen and rendering a diagnosis. For example, there is need for rapid detection of residual cancer on the surface of tumor resection specimens during excisional surgeries, which is known as intraoperative tumor margin assessment. Additionally, rapid assessment of biopsy specimens at the point-of-care could enable clinicians to confirm that a suspicious lesion is successfully sampled, thus preventing an unnecessary repeat biopsy procedure. Rapid and low cost histological processing could also be potentially useful in settings lacking the human resources and equipment necessary to perform standard histologic assessment. Lastly, automated interpretation of tissue samples could potentially reduce inter-observer error, particularly in the diagnosis of borderline lesions. </p><p>To address these needs, high quality microscopic images of the tissue must be obtained in rapid timeframes, in order for a pathologic assessment to be useful for guiding the intervention. Optical microscopy is a powerful technique to obtain high-resolution images of tissue morphology in real-time at the point of care, without the need for tissue processing. In particular, a number of groups have combined fluorescence microscopy with vital fluorescent stains to visualize micro-anatomical features of thick (i.e. unsectioned or unprocessed) tissue. However, robust methods for segmentation and quantitative analysis of heterogeneous images are essential to enable automated diagnosis. Thus, the goal of this work was to obtain high resolution imaging of tissue morphology through employing fluorescence microscopy and vital fluorescent stains and to develop a quantitative strategy to segment and quantify tissue features in heterogeneous images, such as nuclei and the surrounding stroma, which will enable automated diagnosis of thick tissues.</p><p>To achieve these goals, three specific aims were proposed. The first aim was to develop an image processing method that can differentiate nuclei from background tissue heterogeneity and enable automated diagnosis of thick tissue at the point of care. A computational technique called sparse component analysis (SCA) was adapted to isolate features of interest, such as nuclei, from the background. SCA has been used previously in the image processing community for image compression, enhancement, and restoration, but has never been applied to separate distinct tissue types in a heterogeneous image. In combination with a high resolution fluorescence microendoscope (HRME) and a contrast agent acriflavine, the utility of this technique was demonstrated through imaging preclinical sarcoma tumor margins. Acriflavine localizes to the nuclei of cells where it reversibly associates with RNA and DNA. Additionally, acriflavine shows some affinity for collagen and muscle. SCA was adapted to isolate acriflavine positive features or APFs (which correspond to RNA and DNA) from background tissue heterogeneity. The circle transform (CT) was applied to the SCA output to quantify the size and density of overlapping APFs. The sensitivity of the SCA+CT approach to variations in APF size, density and background heterogeneity was demonstrated through simulations. Specifically, SCA+CT achieved the lowest errors for higher contrast ratios and larger APF sizes. When applied to tissue images of excised sarcoma margins, SCA+CT correctly isolated APFs and showed consistently increased density in tumor and tumor + muscle images compared to images containing muscle. Next, variables were quantified from images of resected primary sarcomas and used to optimize a multivariate model. The sensitivity and specificity for differentiating positive from negative ex vivo resected tumor margins was 82% and 75%. The utility of this approach was further tested by imaging the in vivo tumor cavities from 34 mice after resection of a sarcoma with local recurrence as a bench mark. When applied prospectively to images from the tumor cavity, the sensitivity and specificity for differentiating local recurrence was 78% and 82%. The results indicate that SCA+CT can accurately delineate APFs in heterogeneous tissue, which is essential to enable automated and rapid surveillance of tissue pathology. </p><p>Two primary challenges were identified in the work in aim 1. First, while SCA can be used to isolate features, such as APFs, from heterogeneous images, its performance is limited by the contrast between APFs and the background. Second, while it is feasible to create mosaics by scanning a sarcoma tumor bed in a mouse, which is on the order of 3-7 mm in any one dimension, it is not feasible to evaluate an entire human surgical margin. Thus, improvements to the microscopic imaging system were made to (1) improve image contrast through rejecting out-of-focus background fluorescence and to (2) increase the field of view (FOV) while maintaining the sub-cellular resolution needed for delineation of nuclei. To address these challenges, a technique called structured illumination microscopy (SIM) was employed in which the entire FOV is illuminated with a defined spatial pattern rather than scanning a focal spot, such as in confocal microscopy. </p><p>Thus, the second aim was to improve image contrast and increase the FOV through employing wide-field, non-contact structured illumination microscopy and optimize the segmentation algorithm for new imaging modality. Both image contrast and FOV were increased through the development of a wide-field fluorescence SIM system. Clear improvement in image contrast was seen in structured illumination images compared to uniform illumination images. Additionally, the FOV is over 13X larger than the fluorescence microendoscope used in aim 1. Initial segmentation results of SIM images revealed that SCA is unable to segment large numbers of APFs in the tumor images. Because the FOV of the SIM system is over 13X larger than the FOV of the fluorescence microendoscope, dense collections of APFs commonly seen in tumor images could no longer be sparsely represented, and the fundamental sparsity assumption associated with SCA was no longer met. Thus, an algorithm called maximally stable extremal regions (MSER) was investigated as an alternative approach for APF segmentation in SIM images. MSER was able to accurately segment large numbers of APFs in SIM images of tumor tissue. In addition to optimizing MSER for SIM image segmentation, an optimal frequency of the illumination pattern used in SIM was carefully selected because the image signal to noise ratio (SNR) is dependent on the grid frequency. A grid frequency of 31.7 mm-1 led to the highest SNR and lowest percent error associated with MSER segmentation. </p><p>Once MSER was optimized for SIM image segmentation and the optimal grid frequency was selected, a quantitative model was developed to diagnose mouse sarcoma tumor margins that were imaged ex vivo with SIM. Tumor margins were stained with acridine orange (AO) in aim 2 because AO was found to stain the sarcoma tissue more brightly than acriflavine. Both acriflavine and AO are intravital dyes, which have been shown to stain nuclei, skeletal muscle, and collagenous stroma. A tissue-type classification model was developed to differentiate localized regions (75x75 µm) of tumor from skeletal muscle and adipose tissue based on the MSER segmentation output. Specifically, a logistic regression model was used to classify each localized region. The logistic regression model yielded an output in terms of probability (0-100%) that tumor was located within each 75x75 µm region. The model performance was tested using a receiver operator characteristic (ROC) curve analysis that revealed 77% sensitivity and 81% specificity. For margin classification, the whole margin image was divided into localized regions and this tissue-type classification model was applied. In a subset of 6 margins (3 negative, 3 positive), it was shown that with a tumor probability threshold of 50%, 8% of all regions from negative margins exceeded this threshold, while over 17% of all regions exceeded the threshold in the positive margins. Thus, 8% of regions in negative margins were considered false positives. These false positive regions are likely due to the high density of APFs present in normal tissues, which clearly demonstrates a challenge in implementing this automatic algorithm based on AO staining alone. </p><p>Thus, the third aim was to improve the specificity of the diagnostic model through leveraging other sources of contrast. Modifications were made to the SIM system to enable fluorescence imaging at a variety of wavelengths. Specifically, the SIM system was modified to enabling imaging of red fluorescent protein (RFP) expressing sarcomas, which were used to delineate the location of tumor cells within each image. Initial analysis of AO stained panels confirmed that there was room for improvement in tumor detection, particularly in regards to false positive regions that were negative for RFP. One approach for improving the specificity of the diagnostic model was to investigate using a fluorophore that was more specific to staining tumor. Specifically, tetracycline was selected because it appeared to specifically stain freshly excised tumor tissue in a matter of minutes, and was non-toxic and stable in solution. Results indicated that tetracycline staining has promise for increasing the specificity of tumor detection in SIM images of a preclinical sarcoma model and further investigation is warranted. </p><p>In conclusion, this work presents the development of a combination of tools that is capable of automated segmentation and quantification of micro-anatomical images of thick tissue. When compared to the fluorescence microendoscope, wide-field multispectral fluorescence SIM imaging provided improved image contrast, a larger FOV with comparable resolution, and the ability to image a variety of fluorophores. MSER was an appropriate and rapid approach to segment dense collections of APFs from wide-field SIM images. Variables that reflect the morphology of the tissue, such as the density, size, and shape of nuclei and nucleoli, can be used to automatically diagnose SIM images. The clinical utility of SIM imaging and MSER segmentation to detect microscopic residual disease has been demonstrated by imaging excised preclinical sarcoma margins. Ultimately, this work demonstrates that fluorescence imaging of tissue micro-anatomy combined with a specialized algorithm for delineation and quantification of features is a means for rapid, non-destructive and automated detection of microscopic disease, which could improve cancer management in a variety of clinical scenarios.</p> / Dissertation

In this dissertation we investigate the behavior of radially symmetric non-Euclidean plates of thickness t with constant negative Gaussian curvature. We present a complete study of these plates using the Föppl-von Kármán and Kirchhoff reduced theories of elasticity. Motivated by experimental results, we focus on deformations with a periodic profile. For the Föppl-von Kármán model, we prove rigorously that minimizers of the elastic energy converge to saddle shaped isometric immersions. In studying this convergence, we prove rigorous upper and lower bounds for the energy that scale like the thickness t squared. Furthermore, for deformation with n-waves we prove that the lower bound scales like nt² while the upper bound scales like n²t². We also investigate the scaling with thickness of boundary layers where the stretching energy is concentrated with decreasing thickness. For the Kichhoff model, we investigate isometric immersions of disks with constant negative curvature into R³, and the minimizers for the bending energy, i.e. the L² norm of the principal curvatures over the class of W^2,2 isometric immersions. We show the existence of smooth immersions of arbitrarily large geodesic balls in H² into R³. In elucidating the connection between these immersions and the nonexistence/ singularity results of Hilbert and Amsler, we obtain a lower bound for the L^∞ norm of the principal curvatures for such smooth isometric immersions. We also construct piecewise smooth isometric immersions that have a periodic profile, are globally W^2,2, and numerically have lower bending energy than their smooth counterparts. The number of periods in these configurations is set by the condition that the principal curvatures of the surface remain finite and grow approximately exponentially with the radius of the disc.

Following trauma, such as an impact injury or stroke, brain tissue can swell. Swelling is the result of water accumulation in the tissue that is driven by pathological changes, such as increased permeability of the capillary walls and osmotic pressure changes within the tissue. Swelling causes increased intracranial pressure and mechanical deformation of the brain tissue, exacerbating the original injury. Furthermore, prolonged local swelling can lead to the spread of damage to the (initially undamaged) surrounding tissue, since compression and increased intracranial pressure may restrict blood flow in this tissue. In this thesis, we develop mathematical models to examine the consequences of pathophysiological damage mechanisms on the swelling, and associated stress and strain, experienced by brain tissue. Mixture theory is used to represent brain tissue as a mixture of elastic solid, fluid and solutes. This modelling approach allows elastic deformations to be coupled with hydrodynamic pressure and osmotic gradients; the consequences of different mechanisms of damage may then be quantified. We consider three particular problems motivated by experimental observations of swelling brain tissue. Firstly, we investigate the swelling of isolated, damaged, brain tissue slices; we show that mechanisms leading to an osmotic pressure difference between the tissue slice and its surroundings can explain experimental observations for swollen tissue slices. Secondly, we use our modelling approach to demonstrate that local changes in capillary permeability can cause significant stresses and strains in the surrounding tissue. Thirdly, we investigate the conditions under which a locally swollen, damaged, region can cause compression of the vasculature within the surrounding tissue, and potentially result in damage propagation. To do this, we propose a coupled model for the oxygen concentration within, and mechanical deformation of, brain tissue. We use our model to assess the impact of treatment strategies on damage propagation through the tissue, and show that performing a craniectomy reduces the extent of propagation.