Summer pasture-associated recurrent airway obstruction (SPARAO) is characterized by reversible airway obstruction resulting from airway hyper-reactivity to aeroallergens, mucus accumulation, and airway inflammation. These are key clinical features that are shared with human asthma, suggesting SPARAO’s utility as an animal asthma model. SPARAO affects horses maintained on pasture in conditions of high heat and humidity. Common in the southeastern United States, the cause of SPARAO is unknown, but is presumed to reflect reactivity to seasonally inhaled pasture-associated aeroallergens. This investigation sought to identify well-characterized histopathological lesions of human asthma, collectively termed ‘asthmatic remodeling’, in lung tissue from horses with SPARAO. Two histological staining techniques were used: H&E and Movat’s Pentachrome. Similar to chronic asthma, lung tissue from horses with SPARAO demonstrates statistically significant increases in airway smooth muscle, fibrosis, airway occlusion and inflammation, goblet cell hyperplasia, and remodeling of terminal bronchioles and elastin fibers.

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The methodology to measure the performance of urban streets was significantly revised in the latest edition of the Highway Capacity Manual (HCM 2010). Urban Streets, which include urban and suburban signalized arterial highways, typically serve the four modes of transportation (auto, transit, pedestrian and bicycle) and are frequently congested. Analyzing both recurrent and non-recurrent conditions is essential. In this dissertation, the author addressed several urban streets related issues by developing an alternative method to measure recurrent multimodal conditions on urban streets; gathering feedback relating to the key elements of the developed method; and developing a probabilistic method to analyze and measure non-recurrent conditions. Real life sample applications were performed for both developed methods. The developed multimodal method addresses the following: (1) the use of level of service (LOS) step functions; (2) the comparability of LOS results across modes; (3) the impacts of modes on other modes; (4) the establishment of thresholds; (5) accuracy; and (6) user perceptions in measuring multimodal conditions on urban streets. Feedback gathered from transportation professionals through focus group meetings and surveys supported most of the features of the developed multimodal method and provided default values for method application. They were divided on the naming of condition levels and on the number of condition levels to use. Non-recurrent conditions were addressed through the development of a Markovian probabilistic method to analyze and measure the resilience of congested, signalized, arterial highways, for which availability of existing analytical tools is limited. The method results provide a plexiform of information about the rate and speed of recovery of the arterial traffic flow. / Ph. D.

Das mediale patello-femorale Ligament (MPFL) wurde in den letzten Jahren und Jahrzehnten als maßgeblicher passiver Stabilisator der Kniescheibe identifiziert und in biomechanischen Studien beschrieben. Auch wurden die verschiedenen Möglichkeiten der operativen Rekonstruktion des MPFL und deren klinisches Outcome bei patellofemoraler Instabilität in zahlreichen Studien beschrieben sowie relevante Ergebnisse für den klinischen Alltag formuliert. Ziel dieser Arbeit war es, die MPFL-Ersatzplastik als Revisionseingriff mit dem Outcome bei Primäreingriffen zu vergleichen und Faktoren zu bestimmen, die das klinische Outcome beeinflussen. Hierzu wurden 61 Patienten, die von Januar 2009 bis Dezember 2012 in der Klinik für Unfall- und Wiederherstellungschirurgie des Diakoniekrankenhauses Friederikenstift gGmbH Hannover operativ mittels MPFL-Ersatzplastik stabilisiert worden sind, untersucht. Retrospektiv nach Aktenlage und im Rahmen einer klinischen Nachuntersuchung wurden anhand eines standardisierten Studienprotokolls verschiedene Ausgangs- und Outcome-Parameter erhoben und mittels IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp. Released 2011 ausgewertet. Es zeigte sich, dass die Patienten der Primärgruppe eine signifikante Verbesserung durch die Operation erzielen konnten, bei den Patienten der Revisionsgruppe traf dies nicht auf alle Parameter zu. Im Vergleich der Ausgangs- und Outcome-Parameter der Primär- und Revisionsgruppe zeigten sich keine signifikanten Unterschiede. Des Weiteren zeigte sich, dass die Ausgangsparameter Alter bei OP, operativ-versorgte Seite, BMI, Beruf, generelle sportliche Betätigung, verwendete Fadenanker zur Transplantatfixierung an der Patella und Lage der Bohrkanäle in der Patella das Outcome der Operation signifikant beeinflussten.

The first half of this thesis addressed the clinical question of whether the phenotype of peripheral immune cells is affected by the normal menstrual cycle and whether there are differences in women with recurrent unexplained miscarriage. In chapter 2, a mid-luteal type 1 shift was demonstrated in NK^dim and cytotoxic T cells in the menstrual cycle. In addition, women with recurrent miscarriage had increased numbers of type 1 (IL-18R+) cytotoxic lymphocytes and an increased number of NK^dim and NK^bright cells in the mid-luteal phase of the cycle. The shift to type 2 immunity seen in normal pregnancy has been previously identified from the second half of the first trimester. In chapter 3 this type 2 shift was seen in NK and T cells as early as 9 days post implantation. ST2L (the ligand for IL-33 and a marker of type 2 cells) was consistently up regulated at this very early stage post implantation in women who were pregnant. The second half of this thesis investigated IL-33 and ST2 in normal and pathological pregnancy. In chapter 4 it was shown that circulating IL-33 did not change over the course of pregnancy but that sST2 (the soluble decoy receptor) increased significantly in the 3rd trimester of normal pregnancy. Both IL-33 and ST2 were variably expressed by the pre-implantation human blastocyst, as well as by the 1st and 3rd trimester placenta. Finally, chapter 5 showed a potential role for ST2 in pre-eclampsia, an inflammatory disease of pregnancy. sST2 was significantly elevated in the third trimester in women who went on to develop pre-eclampsia even prior to the onset of disease. Using an in vitro model of placental perfusion, it was shown that sST2 can be secreted by the placenta, suggesting that sST2 may play a significant role in pregnancies complicated by this disease.

Breast fibroadenomas account for approximately 25% of all lesions in asymptomatic women, resulting in large health care costs every year. There are 3 different variations of the disease: simple, juvenile giant and multiple. Patients may have different management and treatment options available to them depending on which variation they have. Of particular interest are female adolescents, who are at most risk for developing these lesions. With this age group not only is it important to pursue options that are minimally invasive and effective, but there are psychosocial implications to consider regarding the cosmetic changes that may occur with the disease, as well as generalized anxiety over having a breast lump. These issues are important to consider for physicians when recommending a treatment or management option. After a systematic review of all options available, it appears the best management method is the conservative treatment as it minimizes invasive intervention and operates on the principle that 10-40% of lesions regress on their own; however, there may be times that adolescents are uncomfortable with this treatment due to anxiety and other uneasiness about having a lesion remain in their breasts, despite the low chance of malignancy associated with breast fibroadenomas. Minimally invasive procedures are being developed in order to minimize possible iatrogenic injury to the developing breasts as well as maintain efficiency and good cosmesis post-procedure. Cryoablation is a minimally invasive technique utilizing extreme cold temperatures for lesion excision that is not currently widely used, however it has great potential to replace traditional open surgical excision.

Consider a dynamical system which is positively expansive and satisfies the condition of specification. We further study the topological entropy of the level sets for local Poincare recurrence, i.e. the recurrence spectrum. It turns out that the spectrum is quite irrational as any level set has the same (topological) entropy as the whole system. The erratic recurrence behavior of the orbits brings chaos. For the system concerned, we show that it contains a Xiong chaotic set C which is large in the sense that the intersection of any non-empty open set with C has the same topological entropy as the whole system. The ergodic average can be regarded as a certain recurrence average. We give multifractal analysis of the generalized spectrum for ergodic average, which incorporates the information of the set of divergence points. Note that the set of divergence points for Poincare recurrence or ergodic average has measure zero with respect to any invariant measure. (A Xiong chaotic set may has measure zero with respect to some invariant measures with full support.) The above results support the point of view that small set unobservable in measure may account for the anomalous chaotic behavior of the whole system. / The thesis is on the recurrence and chaotic behavior of a dynamical system. Let the local Poincare recurrence rate at a point be defined as the exponential rate of the first return time of the orbit into its neighborhoods defined by the Bowen metric. Given any reference invariant probability measure mu, we show that the rate equals to the local entropy of mu a.e. Hence, the integration of the rate is exactly the (measure theoretic) entropy of the measure mu. / Shu, Lin. / "January 2007." / Adviser: Ka-Sing Lau. / Source: Dissertation Abstracts International, Volume: 68-08, Section: B, page: 5286. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 83-91). / 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.

Object recognition in the visual cortex is based on a hierarchical architecture, in which specialized brain regions along the ventral pathway extract object features of increasing levels of complexity, accompanied by greater invariance in stimulus size, position, and orientation. Recent theoretical studies postulate a non-linear pooling function, such as the maximum (MAX) operation could be fundamental in achieving such invariance. In this paper, we are concerned with neurally plausible mechanisms that may be involved in realizing the MAX operation. Four canonical circuits are proposed, each based on neural mechanisms that have been previously discussed in the context of cortical processing. Through simulations and mathematical analysis, we examine the relative performance and robustness of these mechanisms. We derive experimentally verifiable predictions for each circuit and discuss their respective physiological considerations.

For the last twenty years, several assumptions have been expressed in the fields of information processing, neurophysiology and cognitive sciences. First, neural networks and their dynamical behaviors in terms of attractors is the natural way adopted by the brain to encode information. Any information item to be stored in the neural network should be coded in some way or another in one of the dynamical attractors of the brain, and retrieved by stimulating the network to trap its dynamics in the desired item’s basin of attraction. The second view shared by neural network researchers is to base the learning of the synaptic matrix on a local Hebbian mechanism. The third assumption is the presence of chaos and the benefit gained by its presence. Chaos, although very simply produced, inherently possesses an infinite amount of cyclic regimes that can be exploited for coding information. Moreover, the network randomly wanders around these unstable regimes in a spontaneous way, thus rapidly proposing alternative responses to external stimuli, and being easily able to switch from one of these potential attractors to another in response to any incoming stimulus. Finally, since their introduction sixty years ago, cell assemblies have proved to be a powerful paradigm for brain information processing. After their introduction in artificial intelligence, cell assemblies became commonly used in computational neuroscience as a neural substrate for content addressable memories. Based on these assumptions, this thesis provides a computer model of neural network simulation of a brain-like memory. It first shows experimentally that the more information is to be stored in robust cyclic attractors, the more chaos appears as a regime in the background, erratically itinerating among brief appearances of these attractors. Chaos does not appear to be the cause, but the consequence of the learning. However, it appears as an helpful consequence that widens the network’s encoding capacity. To learn the information to be stored, two supervised iterative Hebbian learning algorithm are proposed. One leaves the semantics of the attractors to be associated with the feeding data unprescribed, while the other defines it a priori. Both algorithms show good results, even though the first one is more robust and has a greater storing capacity. Using these promising results, a biologically plausible alternative to these algorithms is proposed using cell assemblies as substrate for information. Even though this is not new, the mechanisms underlying their formation are poorly understood and, so far, there are no biologically plausible algorithms that can explain how external stimuli can be online stored in cell assemblies. This thesis provide such a solution combining a fast Hebbian/anti-Hebbian learning of the network's recurrent connections for the creation of new cell assemblies, and a slower feedback signal which stabilizes the cell assemblies by learning the feed forward input connections. This last mechanism is inspired by the retroaxonal hypothesis.