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A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy / This thesis is a study of quantifiable variation in the geometric shape of the superior articular surface of the talus of higher primates, with special reference to fossil tali of Plio- Pleistocene hominids. (Abbreviation abstract ) / AC2017

Zusammenfassung Histomorphometrische Befunde am M. gluteus medius von Pferden ausgewählter deutscher Warmblutrassen - Selektionskriterium für die sportliche Veranlagung? (96 S., 11 Abb., 52 Tab., 131 Lit.) Zur Untersuchung histomorphometrischer Indizes wurden aus dem M. gluteus medius von Warmblut-Pferden ausgewählter deutscher Zuchtgebiete Bioptate entnommen. Insgesamt standen 64 zweijährige Hengste zur Verfügung. Die Biopsien wurden an einem definierten Punkt und bei einer immer gleichen Entnahmetiefe von 5 cm mit der Biopsiekanüle nach BERGSTRÖM (1962) durchgeführt. Eine Auswertung der Muskelproben erfolgte im Hinblick auf die Rassenzugehörigkeit, hinsichtlich Züchtung der Pferde für den Dressur- bzw. Springsport, mit Bezug auf das Körurteil sowie unter Berücksichtigung der Abstammung von verschiedenen väterlichen Blutlinien. Dazu kam die histochemische Methode der sauren Kreuzkombination nach ZIEGAN (1979) zur Anwendung, welche neben den physiologischen auch die biochemischen Eigenschaften der Muskelfasern berücksichtigt. Demzufolge wurde eine Differenzierung in die Fasertypen STO (slow-twitch-oxidative), FTO (fast-twitch-oxidative), Fasern des Intermediärtyps und FTG (fast-twitch-glycolytic) vorgenommen. Für diese Fasertypen wurde die relative Anzahl, die absolute und die relative Faserquerschnittsfläche sowie die Quotienten schnell-/langsam-kontrahierende Fasern (F/S), oxidative/glykolytische (Ox/G) Muskelfasern und FTO/FTG ermittelt. Zwischen Pferden verschiedener deutscher Warmblutrassen ließen sich signifikante Unterschiede im STO- (p< 0,001) und FTO-Faseranteil (p< 0,01) nachweisen. Warmblutpferde Trakehner Abstammung wiesen dabei mit 35,9 % den größten Anteil langsamer Muskelfasern (STO) und mit 33,8 % den geringsten Anteil schnell-kontrahierender, oxidativer Fasern (FTO) auf. Die gegensätzlichen Extremwerte bezüglich dieser beiden Fasertypen nahmen die Pferde des Zuchtgebietes Westfalen ein. Auch die absoluten Faserquerschnittsflächen langsam-kontrahierender Muskelfasern von Pferden verschiedener Rassen waren signifikant (p< 0,05) verschieden. Wiederum nahmen mit 2957 µm2 die Trakehner eine Spitzenposition ein. Im Vergleich der Werte der relativen Faserquerschnittsfläche von Pferden verschiedener Rassen wurde auch ein signifikanter Unterschied bei den FTG-Fasern deutlich (p< 0,01). Dressurpferde besaßen mit 26,6 % einen signifikant (p< 0,05) höheren STO-Faseranteil als Springpferde mit einem Wert von 21,9 %. Umgekehrt verhielt sich der prozentuale FTO-Faseranteil mit 46,7 % bei Spring- und 38,8 % bei Dressurpferden (p< 0,05). Die Werte der relativen Faseranzahl und der relativen Faserfläche wiesen einen Korrelationskoeffizienten von r=0,92 auf. Demzufolge bestanden zwischen Dressur- und Springpferden auch bei der relativen Faserquerschnittsfläche signifikante Unterschiede für STO- (p< 0,05) und FTO-Fasern (p< 0,001). „Gekörte Hengste“ hatten mit 20 % signifikant (p< 0,05) weniger langsam-kontrahierende Muskelfasern als „Nicht gekörte“ Hengste mit 25 %. Auch für die relative Faserquerschnittsfläche traf dieses Verhältnis signifikant (p< 0,05) zu. Es konnte weiterhin gezeigt werden, daß Nachkommen von verschiedenen väterlichen Blutlinien signifikant im STO- (p< 0,01) und FTO-Faseranteil (p< 0,001) sowie bezüglich der relativen Faserquerschnittsfläche von STO- (p< 0,001), FTO- (p< 0,01) und FTG-Fasern (p< 0,05) und hinsichtlich der absoluten Faserfläche der langsamen Muskelfasern (p< 0,05) voneinander abweichen. Aus den Ergebnissen konnten folgende Erkenntnisse gewonnen werden: 1. Die Befunde weisen auf eine enge Abhängigkeit der Muskelfasertypenkomposition des Pferdes von genetischen Faktoren hin. 2. Bereits zwischen Pferden anderer Rassen beobachtete Unterschiede hinsichtlich morphologischer Muskelindizes lassen sich auch bei Pferden verschiedener deutscher Warmblut-Pferderassen aufzeigen. 3. Pferde, die seit mehreren Generationen speziell für eine Nutzung im Springsport gezüchtet worden sind, besitzen einen höheren prozentualen FTO-Faseranteil. Dieser verleiht ihnen wahrscheinlich die Fähigkeit, in der Absprungphase ein enormes Maß an Kraft zu generieren. Dressurpferde haben Arbeit von vergleichsweise niedriger Intensität, aber langer Dauer zu verrichten. Daraus ergibt sich die Möglichkeit, die Muskelbiopsie bereits bei jungen Pferden als Selektionskriterium einzusetzen. 4. Die Ergebnisse der „Gekörten Hengste“ weisen auf eine Selektion zugunsten der Individuen mit hohem FTO- und dementsprechend niedrigem STO-Faseranteil hin, was auf einen Zusammenhang zwischen der Muskelfasertypenzusammensetzung und der Bewegungsqualität eines Pferdes hindeutet. / Summary Histomorphometric findings of the gluteus medius muscle of horses from selected german warm-blooded breeds - selection criterion for athletic ability? (96 p., 11 fig., 52 tables, 131 ref.) For examining the histomorphometric muscle indices biopsies were taken of warm-blooded horses descending from selected German breeds. Biopsies were taken at standardized depth of 5 cm from the left gluteus medius muscle of 64 two-year-old stallions using a BERGSTROEM biopsy needle (1962). Muscle samples were evaluated according to different breeds, the aptitude for dressage or show jumping, the possession of a breeding licence and the derivation of different paternal bloodlines. The histochemical method used was that described by ZIEGAN (1979), which considers the physiological as well as the biochemical properties of muscle fibres. Therefore muscle fibres were distinguished in STO, FTO, fibres of intermediate type and FTG. For these fibre the types relative number, absolute and relative cross-sectional fibre area as well as the quotient fast-/slow-twitch fibers, oxidative/glycolytic muscle fibers and FTO/FTG were determined. Between horses of different German warm-blooded breeds there were significant differences in the percentage of STO (p< 0,001) and FTO-fibres (p< 0,01). Trakehner horses had the highest percentage of slow-twitch fibres with 35,9 %, and the lowest percentage of FTO-fibres with 33,8 %. The other two extremes according to these fibre types occured in Westphalian horses. Absolute cross-sectional STO-fibre areas were also significantly different between horses of different breeds (p< 0,05). Again, the Trakehner horses were in the lead with 2956,89 µm2. Comparing the relative muscle fibre area of differently bred horses, FTG-fibres also turned out to be significantly different (p< 0,01) from each other. Dressage horses had with 26,6 % a significantly higher (p< 0,05) proportion of STO-fibres than show jumping horses with a percentage of 21,9 %. Show jumping horses had a higher percentage of FTO-fibres with 46,7 % than dressage horses with 38,8 % (p< 0,05). Expressing a high correlation of relative number and relative cross-sectional fibre area (r< 0,92), the latter criterion also turned out to be different for STO- (p< 0,05) and FTO-fibres (p< 0,001). Licenced breeding stallions showed a significantly (p< 0,05) lower proportion of slow-twitch fibres with 20 % than stallions without breeding permission with 25 %. This relation also turned out to be significant for the relative fibre area (p< 0,05) . Furthermore it was found that offsprings of different paternal bloodlines differ from one another according to the percentage of STO- (p< 0,01) and FTO-fibres (p< 0,001), according to relative cross-sectional fibre areas of STO- (p< 0,001), FTO- (p< 0,01) and FTG-fibres (p< 0,05) and according to absolute fibre areas of slow-twitch muscle fibres (p< 0,05). These results suggest following conclusions: 1. The findings show a high correlation between muscle fiber type composition and genetic factors in the horse. 2. Earlier observed differences in morphological muscle indices between different races of horses were also evident between horses of different german warm-blooded breeds. 3. Horses, which have been bred specifically for show jumping over numerous generations, possess a higher percentage of FTO-fibres. This probably enables them to generate an enormous amount of power in the moment of take-off. Dressage horses have to perform exercises of comparatively low intensity but long duration. Therefore the muscle biopsy is a usefull selection criterion in young horses. 4. The results from the licenced breeding stallions indicate selection in favour of individuals having a high percentage of FTO- and a low percentage of STO-fibers, which may be related to muscle fibre properties and the locomotor pattern of the horse.

The role of chemokines in immune function is clearly established. Recent evidence suggests that these molecules also play an important role in the CNS as modulators of neuronal activity. The chemokine CXCL12 has been identified in several regions of the adult rat brain including the substantia nigra, ventral tegmental area and caudate putamen. CXCR4, a receptor activated by CXCL12, is expressed by dopaminergic neurons in the substantia nigra. The research presented herein explored the behavioral modulation of CXCL12, expression of the CXCR4 receptor in the forebrain of the adult rat and the effect of CXCL12 administration on extracellular dopamine and glutamate release in the medial shell of the nucleus accumbens. This research furthered our understanding of how CXCL12 can affect behavior and suggested that the modulation of cocaine-induced behavior by CXCL12 is due to an interaction with CXCR4 receptors in the mesolimbic and nigrostriatal dopamine pathways. The data presented tested the effects of intracranial injections of CXCL12 on cocaineinduced locomotion and stereotypic activity in adult male Sprague Dawley rats. Results demonstrate that intracerebroventricular administration of CXCL12 (25 ng/4 μl) 15 minutes prior to cocaine (20 mg/kg IP) produced a significant potentiation of both ambulatory and stereotypic activity as compared to cocaine alone. The effects of CXCL12 were blocked by administration of the selective CXCR4 antagonist, AMD 3100. Administration of CXCL12 into specific brain regions was performed to further understand the site of action of CXCL12. Bilateral administration of CXCL12 (25 ng/0.5 μl) into the ventral tegmental area 15 minutes prior to cocaine (20 mg/kg IP) significantly potentiated cocaine-induced ambulatory activity, whereas microinjections of CXCL12 into the caudate putamen selectively increased stereotypy. Conversely, administration of CXCL12 into the lateral shell of the nucleus accumbens resulted in an inhibition of cocaine-stimulated ambulatory activity. No alterations in ambulatory or stereotypic activity were observed following CXCL12 administration into the core of the nucleus accumbens. Immunohistochemistry results showed evidence of CXCR4 within the caudate putamen and lateral shell of the nucleus accumbens. Dual labeling immunofluorescence demonstrated that CXCR4 is co-expressed on cholinergic and GABAergic neurons, including co-localization with the D1 dopamine receptor in both the caudate putamen and lateral shell of the nucleus accumbens. Results demonstrated that CXCR4 is co-expressed with choline acetyl transferase, a marker for cholinergic neurons, with GAD C38, a marker for GABAergic neurons, and with the D1 dopamine receptor, also a marker for GABAergic medium spiny neurons. High pressure liquid chromatography studies were conducted using brain dialysate collected from microdialysis probes surgically implanted in the medial shell of the nucleus accumbens. Results demonstrated no significant change in extracellular dopamine or glutamate following an acute administration of CXCL12. The research presented herein sought to determine the behavioral modifications of CXCL12 as well as the localization of CXCR4 in the forebrain of the adult rat. This research also examined changes in extracellular dopamine and glutamate levels following CXCL12 administration. Results demonstrated that CXCL12 does alter the behavioral activity of cocaine. Results also showed that CXCR4 is localized on cholinergic and GABAergic neurons that could be contributing to the behavioral modification. These results have extended our understanding of the complex mechanisms of CXCL12 and CXCR4 in the mesolimbic and nigrostriatal dopamine pathways of the adult rat brain. / Pharmacology

<p>In Virtual Reality (VR), users often need to explore a large virtual space within a limited physical space. However, as one of the most popular and commonly-used methods for such room-scale problems, teleport always relies on hand-based controllers. In applications that require consistent hand interaction, such teleport methods may conflict with the users' hand operation, and make them uncomfortable, thus affecting their experience. </p> <p>To alleviate these limitations, this research designs and implements a new interactive object-based VR locomotion method, ManiLoco, as an eye- and foot-based low-cost method. This research also evaluates ManiLoco and compares it with state-of-the-art Point & Teleport and Gaze Teleport methods in a within-subject experiment with 14 participants.</p> <p>The results confirm the viability of the method and its possibility in such applications. ManiLoco makes the users feel much more comfortable with their hands and focus more on the hand interaction in the application while maintaining efficiency and presence. Further, the users' trajectory maps indicate that ManiLoco, despite the introduction of walking, can be applicable to room-scale tracking space. Finally, as a locomotion method only relied on VR head-mounted display (HMD) and software detection, ManiLoco can be easily applied to any VR applications as a plugin.</p>

In the locomotion design space, artificial locomotion is most commonly used when navigating virtual spaces larger than the physical space provided. Some significant challenges to the use of artificial locomotion are however cybersickness and disorientation. Cybersickness is a phenomenon that creates discomfort for the user and is believed to be inflicted by continuous movement and its creation of vection. Contrarily, discrete locomotion interfaces like teleportation do not cause vection or cybersickness for the user. However, because of this, teleportation is unable to offer spatial updating, which is crucial for preventing disorientation. This thesis investigates an alternative to these interfaces that aims to combine their benefits while avoiding their drawbacks in an interface referred to as Stepwise teleportation that consist of short discrete translations, referred to as steps, in the direction chosen by the user. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>