This work gives an overview of the composition of the diet of bats in the eastern Mediterranean and the Middle East, discusses the structure of bat communities in different bioregions of the area in terms of hunting strategies and resource partitioning and last but not least, how echolocation and morphological characteristics of bats affect the composition of the diet. Although some samples were relatively small therefore it is necessary to look soberly at their informative value, and thus their importance is undeniable. The study in some cases provides completely the first information regarding the composition of diet in several species. Asellia arabica mainly catches Coleoptera (Scarabaeidae), Triaenops persicus hunts Lepidoptera, but Heteroptera, Coleoptera (Scarabaeidae) and Orthoptera too, while Triaenops parvus is a specialist in hunting Lepidoptera. Rhinopoma muscatellum hunts mainly Formicoidea, followed by Coleoptera (Melolonthinae) and Heteroptera, Rhinopoma hadramauticum hunts Formicoidea. Lepidoptera of different size, Heteroptera and Coleoptera are the prey of Chaerephon nigeriae. Pipistrellus hanaki has a wide niche breadth as other species of the genus Pipistrellus. In this study Brachycera, Auchenorrhyncha and Coleoptera primarily occurred in its diet. Not yet described species of...

This work gives an overview of the composition of the diet of bats in the eastern Mediterranean and the Middle East, discusses the structure of bat communities in different bioregions of the area in terms of hunting strategies and resource partitioning and last but not least, how echolocation and morphological characteristics of bats affect the composition of the diet. Although some samples were relatively small therefore it is necessary to look soberly at their informative value, and thus their importance is undeniable. The study in some cases provides completely the first information regarding the composition of diet in several species. Asellia arabica mainly catches Coleoptera (Scarabaeidae), Triaenops persicus hunts Lepidoptera, but Heteroptera, Coleoptera (Scarabaeidae) and Orthoptera too, while Triaenops parvus is a specialist in hunting Lepidoptera. Rhinopoma muscatellum hunts mainly Formicoidea, followed by Coleoptera (Melolonthinae) and Heteroptera, Rhinopoma hadramauticum hunts Formicoidea. Lepidoptera of different size, Heteroptera and Coleoptera are the prey of Chaerephon nigeriae. Pipistrellus hanaki has a wide niche breadth as other species of the genus Pipistrellus. In this study Brachycera, Auchenorrhyncha and Coleoptera primarily occurred in its diet. Not yet described species of...

Texas currently maintains the highest installed nameplate capacity and does not require publicly available post-construction monitoring studies that examine the impacts of wind energy production on surrounding fauna. This thesis examines potential wind energy impacts on avian and bat species in Texas through a three-part objective. The first two objectives synthesize literature on variables attractive to species within wind development areas and estimate impacted ranges outside of Texas, based on studies examining wind energy's environmental impacts. The third objective focuses on Texas wind development potential for interaction with rare, threatened and endangered species of birds and bats using GIS analysis with a potential hazard index (PHI) model, which addresses broad-spectrum, high risk variables examined within the first two objectives. Assuming areas with higher wind speeds have potential for wind development, PHI values were calculated for 31 avian and ten bat species, based on an analysis of species range data obtained from the Texas Parks and Wildlife Department and wind data obtained from the National Renewable Energy Laboratory. Results indicate one avian species, Tympanuchus pallidicinctus, is at high risk for wind development interaction on an annual basis, with 20 species of birds and nine species of bats at higher risk during the spring season. This macro-scale approach for identifying high risk species in Texas could be used as a model to apply to other conterminous states' preliminary evaluation of wind energy impacts.

Wenige Studien haben erste Hinweise darauf geliefert, dass die insektivore Fledermausart Mops condylurus ein natürliches Reservoir von Ebolaviren sein könnte. Im Rahmen dieser Doktorarbeit wurden weitere Hinweise gesucht, um die Bedeutung dieser Fledermausart als Reservoirwirt für Ebolaviren besser beurteilen zu können. Dafür wurden die Expressionslevel des Membranproteins Niemann-Pick C1 (NPC1), welches essentiell für den Eintritt von Ebolaviren in ihre Wirtszellen ist, in vitro durch konfokale Mikroskopie und Durchflusszytometrie charakterisiert. In dieser Arbeit generierte Primärzellkulturen aus 12 verschiedenen Organen von M. condylurus zeigten für die meisten Primärzellen deutlich niedrigere Expressionslevel als Kontrollzellen von Mensch, Affe oder einer europäischen Fledermaus. Die untersuchte Replikationskinetik von Ebola virus (EBOV) zeigte in allen Primärzellen von M. condylurus niedrigere Replikationsraten, die meistens mit den niedrigen NPC1 Rezeptor-Expressionsleveln korrelierten. Geringere Mengen von NPC1 könnten in vivo zur Virusreplikation auf niedrigerem Niveau beitragen. Desweiteren zeigten alle Primärzellen von M. condylurus eine hohe Toleranz gegenüber EBOV ohne Zelltot. Eine beobachtete Persistenz in Lungenprimärzellen könnte die intrinsische Fähigkeit widerspiegeln, dass Ebolaviren auch in vivo in dieser Fledermausart persistieren könnten. Mit den geringeren NPC1-Rezeptor-Expressionsleveln, der geringeren Virusreplikation, der hohen Toleranz gegenüber EBOV und der Etablierung von persistenten Infektionen in Primärzellen von M. condylurus wurden in vitro zusätzliche Hinweise gewonnen, die die Wahrscheinlichkeit dieser Fledermausspezies als ein mögliches natürliches Reservoir von Ebolaviren erhöht. Ergebnisse von zusätzlichen Temperaturversuchen lassen vermuten, dass die Heterothermie der Fledermäuse einen Schlüsselfaktor für die Toleranz von Ebolaviren in vivo darstellen und darüber hinaus an der Balance zwischen Viruskontrolle und Virusvermehrung beteiligt sein könnte. / Few studies provide first evidence that Mops condylurus, an insectivorous microbat, could be a natural reservoir for ebolaviruses. The aim of this thesis was to investigate indicators to determine the potential role of this bat species in the ecology of ebolaviruses. Therefore, the expression levels of the membrane protein Niemann-Pick C1 (NPC1), essential for the entry of ebolaviruses into their host cells, were characterized in vitro by confocal microscopy and flow cytometry. Our generated primary cell cultures from 12 different organs from M. condylurus showed significantly lower expression levels in most primary cells compared to control cells from human, monkey or a European bat. In most cases, lower Ebola virus (EBOV) replication rates in primary cells from M. condylurus, determined by RT-qPCR, correlated to lower NPC1 receptor expression levels. Low NPC1 receptor expression levels may contribute to decreased virus replication rates also in vivo. Additionally, all primary cells were highly tolerant to EBOV infections without cell death. The observed establishment of persistent EBOV infections in lung primary cells from M. condylurus may reflect the intrinsic ability to persist in vivo in this bat species. With lower NPC1 receptor expression levels, lower virus replication rates, high tolerance to EBOV infections and establishment of persistent infections in primary cells from M. condylurus, the in vitro experiments provided further evidence that this bat species is a potential reservoir of ebolaviruses. Results from additional temperature experiments suggest, that heterothermy of M. condylurus could be a key factor for tolerance to EBOV infections in vivo and be involved in balancing the level of virus replication.

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No description available.

Polysiloxanes represent a unique class of synthetic polymers, employing a completely inorganic backbone structure comprised of repeating –(Si–O)n– 'siloxane' main chain linkages. This results in an assortment of diverse properties exclusive to the siloxane bond that clearly distinguish them from the –(C–C)n– backbone of purely organic polymers. Previous work has elucidated a methodology for fabricating flexible and elastic crosslinked poly(dimethyl siloxane) (PDMS) constructs with high Mc through a simultaneous crosslinking and chain-extension methodology. However, these constructs suffer the poor mechanical properties typical of lower molecular weight crosslinked siloxanes (e.g. modulus, tear strength, and strain at break). Filled PDMS networks represent another important class of elastomers in which fillers, namely silica and siloxane-based fillers, impart improved mechanical properties to otherwise weak PDMS networks. This work demonstrates that proper silicon-based reinforcing agent selection (e.g. siloxane-based MQ copolymer nanoparticles) and incorporation provides a synergistic enhancement to mechanical properties, whilst maintaining a low viscosity liquid composition, at high loading content, without the use of co-solvents or heating. Rheological analysis evaluates the viscosity while photorheology and photocalorimetry measurements evaluate rate and extent of curing of the various MQ-loaded formulations, demonstrating theoretical printability up to 40 wt% MQ copolymer nanoparticle incorporation. Dynamic mechanical analysis (DMA) and tensile testing evaluated thermomechanical and mechanical properties of the cured nanocomposites as a function of MQ loading content, demonstrating a 3-fold increase in ultimate stress at 50 wt% MQ copolymer nanoparticle incorporation. VP AM of the 40 wt% MQ-loaded, photo-active PDMS formulation demonstrates facile amenability of photo-active PDMS formulations with high MQ-loading content to 3D printing processes with promising results. PDMS polyureas represent an important class of elastomers with unique properties derived from the synergy between the nonpolar nature, unusual flexibility, and low glass transition temperature (Tg) afforded by the backbone siloxane linkages (-Si-O)n- of PDMS and the exceptional hydrogen bond ordering and strength evoked by the bidentate hydrogen bonding of urea. The work herein presents an improved melt polycondensation synthetic methodology, which strategically harnesses the spontaneous pyrolytic degradation of urea to afford a series of PDMS polyureas via reactions at high temperatures in the presence of telechelic amine-terminated oligomeric poly(dimethyl siloxane) (PDMS1.6k-NH2) and optional 1,3-bis(3-aminopropyl)tetramethyldisiloxane (BATS) chain extender. This melt polycondensation approach uniquely circumvents the accustomed prerequisite of isocyanate monomer, solvent, and metal catalysts to afford isocyanate-free PDMS polyureas using bio-derived urea with the only reaction byproduct being ammonia, a fundamental raw ingredient for agricultural and industrial products. As professed above, reinforcement of polysiloxane materials is ascertained via the incorporation of reinforcing fillers or nanoparticles (typically fumed silica) or blocky or segmented development of polymer chains eliciting microphase separation, in order to cajole the elongation potential of polysiloxanes. Herein, a facile approach is detailed towards the synergistic fortification of PDMS-based materials through a collaborative effort between both primary methods of polysiloxane reinforcement. A novel one-pot methodology towards the facile, in situ incorporation of siloxane-based MQ copolymer nanoparticles into segmented PDMS polyureas to afford MQ-loaded thermoplastic and thermoplastic elastomer PDMS polyureas is detailed. The isocyanate-free melt polycondensation achieves visible melt dispersibility of MQ copolymer nanoparticles (good optical clarity) and affords segmented PDMS polyureas while in the presence of MQ nanoparticles, up to 40 wt% MQ, avoiding post-polymerization solvent based mixing, the only other reported alternative. Incorporation of MQ copolymer nanoparticles into segmented PDMS polyureas provides significant enhancements to modulus and ultimate stress properties: results resemble traditional filler effects and are contrary to previous studies and works discussed in Chapter 2 implementing MQ copolymer nanoparticles into chemically-crosslinked PDMS networks. In situ MQ-loaded, isocyanate-free, segmented PDMS polyureas remain compression moldable, affording transparent, free-standing films. / Master of Science / Polysiloxanes, also referred to as 'silicones' encompass a unique and important class of polymers harboring an inorganic backbone. Polysiloxanes, especially poly(dimethyl siloxane) (PDMS) the flagship polymer of the family, observe widespread utilization throughout industry and academia thanks to a plethora of desirable properties such as their incredible elongation potential, stability to irradiation, and facile chemical tunability. A major complication with the utilization of polysiloxanes for mechanical purposes is their poor resistance to defect propagation and material failure. As a result polysiloxane materials ubiquitously observe reinforcement in some fashion: reinforcement is achieved either through the physical or chemical incorporation of a reinforcing agent, such as fumed silica, or through the implementation of a chemical functionality that facilitates reinforcement via phase separation and strong associative properties, such as hydrogen bonding. This research tackles polysiloxane reinforcement via both of these strategies. Facile chemical modification permits the construction PDMS polymer chains that incorporate hydrogen bonding motifs, which phase separate to afford hydrogen bond-reinforced phases that instill vast improvements to elastic behavior, mechanical and elongation properties, and upper-use temperature. Novel nanocomposite formulation through the incorporation of MQ nanoparticles (which observe widespread usage in cosmetics) facilitate further routes toward improved mechanical and elongation properties. Furthermore, with growing interest in additive manufacturing strategies, which permit the construction of complex geometries via an additive approach (as opposed to conventional manufacturing processes, which require subtractive approaches and are limited in geometric complexity), great interest lies in the capability to additively manufacture polysiloxane-based materials. This work also illustrates the development of an MQ-reinforced polysiloxane system that is amenable to conventional vat photopolymerization additive manufacturing: chemical modification of PDMS polymer chains permits the installation of UV-activatable crosslinking motifs, allowing solid geometries to be constructed from a liquid precursor formulation.

No description available.

Thesis (PhD)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: The emergence and re-emergence of viral human pathogens from wildlife sources in the recent past has led to increased studies and surveillance of wildlife for potentially zoonotic agents in order to gain a better understanding of the pathogens, their sources as well as events that may lead to viral emergence. Of the >1407 known human pathogens, 13% are classified as emerging or re-emerging, and 58% as zoonotic; 37% of the (re-)emerging and 19% of the zoonotic pathogens are RNA viruses, accounting for the majority of recently emerged infectious diseases with a zoonotic origin, such as HIV, Ebola, Hendra, Nipah, Influenza and SARS. This study focusses on potentially zoonotic viruses hosted by rodents (Muridae family), shrews (order previously known as Insectivora/Soricomorpha, now reclassified as Eulipotyphla) and bats (order Chiroptera). Rodents and bats represent the largest (~40%) and second largest (~25%) mammalian orders and both occur on every continent except Antarctica. Together, the three mammalian orders investigated represent the most relevant potential sources of new zoonoses. In this study I investigated the occurrence of astroviruses, arenaviruses, coronaviruses and hantaviruses in South African small mammal species belonging to the orders mentioned above. These viruses have either been implicated in recent emerging zoonotic events or are considered to have the potential to cause cross-species transmissions resulting in a zoonotic event. In the first part of the study specimens collected from various bat, rodent and shrew species were screened for viral sequences by broadly reactive PCRs; positive samples were characterised by sequencing and sequence analysis. A separate part of the study focussed on hantavirus disease in humans: a seroprevalance survey was conducted to determine the presence of hantavirus antibodies in the local population. Additionally, acutely ill patients with potential hantavirus disease were tested in an attempt to identify possible acute infections and define clinical hantavirus disease in South Africa. Screening of rodent and shrew specimens resulted in the identification of eight novel arenavirus sequences. Seven of the sequences are related to Merino Walk virus, a recently identified South African arenavirus, and the eighth sequence represents a novel lineage of Old World arenaviruses. Screening of bat specimens resulted in the identification of highly diverse novel astrovirus and coronavirus sequences in various South African bat species, including the identification of a viral sequence closely related to the recently emerged Middle East Respiratory Syndrome coronavirus. While the study did not identify hantavirus infections in any of the acutely ill patients, it found seroprevalences similar to those observed in Europe and West Africa. The results obtained highlight the importance of small mammals in the emergence of potential zoonoses and further reinforce the importance of viral surveillance of relevant wildlife species. Further in-depth studies of naturally infected reservoir host populations are required in order to gain a better understanding of virus-host dynamics and the events that lead to virus emergence. / German Research Foundation (DFG) (project number: KR1293/9-1/13-1) / The Polio Research Foundation and the NHLS Research / Harry Crossley Foundation, the Polio Research Foundation and Stellenbosch University for granting scholarships and bursaries for PhD.

Les chauve-souris représentant un réservoir important pour de nombreux virus pathogènes pour l’homme, un ensemble d’études en évolution moléculaire converge vers l’évidence d’une forte pression de sélection au niveau de gènes impliqués dans l’immunité dans l’ordre Chiroptera. En particulier, les chauves-souris du genre Pteropus hébergent des virus de la famille Henipavirus: Nipah et Hendra. Ces virus sont responsables d'épidémies en Asie du sud-est, et bien qu'ayant un taux d'incidence bas, les maladies résultantes de l'infection ont un taux de létalité allant de 40% à 90% chez l'homme. L’infection atteint aussi la plupart des mammifères avec des symptômes clinique graves, (e.g. porc ou cheval : espèces d’intérêt agronomique). La particularité du genre Pteropus est de ne pas développer ces symptômes cliniques graves d’infection. Afin d'en identifier les bases génétiques, nous avons utilisé l'analyse de sélection positive sur l’ensemble du génome codant sans restreindre notre analyse aux gènes de l’immunité. Nous avons mis en place les outils informatiques innovants et nécessaires au déploiement de cette démarche. Ces analyses, reposent sur des séquences de références pour les génomes de différentes espèces, et en absence du génome de référence pour P. giganteus, nous l’avons préalablement séquencé et assemblé. Or, tous les gènes sous sélection ne sont pas forcément liés à notre phénotype d’intérêt mais possiblement à d’autres (e.g. capacité de vol). Nous avons mis en place un algorithme afin d’établir un lien fonctionnel potentiel entre ces gènes identifiés sous sélection positive et un phénotype d’intérêt. / Bats represent a considerable reservoir for an extensive group of human pathogenic viruses. A number of molecular evolution studies points toward the evidence of a strong selection pressure in Chiroptera immune-related genes. Notably, Pteropus bats host viruses from Henipavirus genus: Nipah and Hendra. These viruses are responsible for epidemics in South-Est Asia, and, while the incidence is low, the resulting diseases are highly lethal, ranging between 40 to 90% in humans. Most of mammals are susceptible to the infection (including pigs and horses, animals valued in agronomy), and develop severe clinical symptoms. Specificity of Pteropus genus lies in the absence of clinical symptoms following the infection. In order to identify the genetic basis of this interesting phenomenon, we applied positive selection analysis to the entire coding genome, without bounding our analysis to immune-regulating genes. We have set breakthrough computational tools, without which our analysis would not have been possible. Reference sequences from genome of several species are the groundwork for our analysis. As P. giganteus reference genome has not yet been resolved, we sequenced and assembled it. However, not all genes under positive selection are necessarily linked to a phenotype of interest, but may be linked to other phenotypes (such as the flying ability). We have thus developed an algorithm to establish a possible functional link between the genes identified under positive selection and a phenotype of interest, which allows new perspectives in phylogenomic research.