Three-dimensional particle tracking is a valuable tool in microfluidics for obtaining information about a system. General Defocus Particle Tracking (GDPT) is a straightforward method of 3D particle tracking that only requires a single-camera plane, making it applicable to existing equipment in a laboratory.  This project's aim was to evaluate the open-source module DefocusTracker which uses GDPT. DefocusTracker was used to track particles that were levitated in a microchip using ultrasonic standing waves.  The effects of different calibration methods used and the evaluation of the acoustic energy density over an active part of a piezo on an microchip device were investigated. Different procedures to generate a depth model from the calibration images showed that the choice of step length affects the accuracy of the depth model. A depth model created from the middle part of the field of view provides more accurate results compared to one made from the edge. Levitation experiments demonstrate that higher applied voltages result in a stronger acoustic energy density field over the field of view. The acoustic energy density field and pressure amplitude field show variations across the active piezo on the device, potentially due to a non-uniform thickness of the fluid layer and variations in energy delivery from the piezo. Overall, GDPT proves to be a useful method for evaluating unknown aspects of a microfluidic system under the influence of ultrasonic standing waves. / Tredimensionell partikelspårning är ett värdefullt verktyg inom mikrofluidik för att få ut information om ett system. Generell ur-fokus partikel spårning (GDPT) är en okomplicerad metod för 3D-partikelspårning som endast kräver ett plan med en kamera. Detta gör den tillämpningsbar på befintliga utrustningar i ett laboratorium.  Syftet med detta projekt var att utvärdera den öppna modulen DefocusTracker som använder sig av GDPT. DefocusTracker användes för att spåra partiklar som leviterades i ett mikrochip med hjälp av stående ultraljudsvågor.  Effekterna av olika kalibreringsmetoder och utvärderingen av den akustiska energitätheten över en aktiv del av en piezo på ett mikrochip undersöktes. Olika metoder för att generera en djup modell från kalibreringsbilderna visade att valet av steglängd påverkar djup modellens noggrannhet. En djup modell som skapats från mitten av synfältet ger mer användbara resultat jämfört med en som skapats från kanten. Levitationsexperiment visar att högre använda spänningar resulterar i ett starkare akustiskt energitäthetsfält över synfältet. Fältet för den akustiska energitätheten och tryckamplituden visar variationer över den aktiva piezon på enheten, vilket kan bero på en ojämn tjocklek på vätskelagret och variationer i energitillförseln från piezon.  Allmänt visar sig GDPT vara en användbar metod för att utvärdera okända aspekter av ett mikrofluidiskt system under påverkan av stående ultraljudsvågor.

Background The foamy virus (FV) replication cycle displays several unique features, which set them apart from orthoretroviruses. First, like other B/D type orthoretroviruses, FV capsids preassemble at the centrosome, but more similar to hepadnaviruses, FV budding is strictly dependent on cognate viral glycoprotein coexpression. Second, the unusually broad host range of FV is thought to be due to use of a very common entry receptor present on host cell plasma membranes, because all cell lines tested in vitro so far are permissive. Results In order to take advantage of modern fluorescent microscopy techniques to study FV replication, we have created FV Gag proteins bearing a variety of protein tags and evaluated these for their ability to support various steps of FV replication. Addition of even small N-terminal HA-tags to FV Gag severely impaired FV particle release. For example, release was completely abrogated by an N-terminal autofluorescent protein (AFP) fusion, despite apparently normal intracellular capsid assembly. In contrast, C-terminal Gag-tags had only minor effects on particle assembly, egress and particle morphogenesis. The infectivity of C-terminal capsid-tagged FV vector particles was reduced up to 100-fold in comparison to wild type; however, infectivity was rescued by coexpression of wild type Gag and assembly of mixed particles. Specific dose-dependent binding of fluorescent FV particles to target cells was demonstrated in an Env-dependent manner, but not binding to target cell-extracted- or synthetic- lipids. Screening of target cells of various origins resulted in the identification of two cell lines, a human erythroid precursor- and a zebrafish- cell line, resistant to FV Env-mediated FV- and HIV-vector transduction. Conclusions We have established functional, autofluorescent foamy viral particles as a valuable new tool to study FV - host cell interactions using modern fluorescent imaging techniques. Furthermore, we succeeded for the first time in identifying two cell lines resistant to Prototype Foamy Virus Env-mediated gene transfer. Interestingly, both cell lines still displayed FV Env-dependent attachment of fluorescent retroviral particles, implying a post-binding block potentially due to lack of putative FV entry cofactors. These cell lines might ultimately lead to the identification of the currently unknown ubiquitous cellular entry receptor(s) of FVs.

The iron ore mining industry makes use of various processes that result in the release of airborne dust into the surrounding atmosphere where workers are exposed, to produce a final product. The deposition in the lung and toxicological influences of airborne dust can be determined by their physical- and chemical characteristics. The Occupational Health and Safety Act (OHSA) regulations for hazardous chemical substances have no current system of how the physical- and chemical properties of particulates originating from specific areas will influence a worker‘s exposure and health, especially for ultrafine particles (UFP). It is therefore imperative to characterise airborne dust containing micrometer and UFP size particles originating from specific areas to determine if there are physical- and chemical characteristics that may or may not have an influence on the workers‘ health. Aim: This pilot study is aimed at the physical- and chemical characterisation of the airborne iron ore dust generated at the process areas of an opencast iron ore mine. Method: Sampled areas included the Primary-secondary crusher, Tertiary crusher, Quaternary crusher and Sifting house. Gravimetric sampling was conducted through the use of static inhalable- and respirable samplers in conjunction with optical- and condensation particle counters that were placed near airborne dust- emitting sources. Physical- and chemical characterisation was done with the use of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Results: The results found in the study indicate high mass concentration levels of inhalable dust at all four process areas, as well as high levels of respirable dust found at the primary- secondary crusher area. Particle size distribution optical particle counter (OPC) results indicate that the majority of particles at all four process areas are in the region of 0.3 μm in size. Condensation particle counter (CPC) results integrated with OPC results indicate that at the primarysecondary and Tertiary crushers the majority of particles are found to be in the size fraction <0.3 μm. SEM analysis indicates that particle agglomeration largely occurs in the airborne iron ore dust. Particle splinters originating from larger particle collisions and breakages are present in the airborne dust. EDS analysis indicates that the elemental majority of the airborne iron ore dust consists of iron, oxygen, carbon, aluminium, silicon, potassium and calcium. The elemental percentages differ from each process area where an increase in iron and decrease in impurities can be seen as the ore moves through the beneficiation process from the Primary-secondary crusher to the Sifting house. Conclusion: The results obtained from the physical- and chemical properties of the airborne iron ore dust indicate high risk of over-exposure to the respiratory system, as well as possible ultrafine particle systemic exposure, that may overwhelm the physiological defense mechanisms of the human body and lead to reactive oxygen species (ROS) formation and the development of pathologies such as siderosis, silicasiderosis and lung cancer. / MSc (Occupational Hygiene), North-West University, Potchefstroom Campus, 2014

Die in Europa und Asien verbreiteten humanpathogenen Hantaviren sind mit dem "Hämorrhagischen Fieber mit renalem Syndrom" (HFRS) assoziiert, während die humanpathogenen Hantaviren in Nord- und Südamerika das "Hantavirale Pulmonale Syndrom" hervorrufen. In Mitteleuropa kommen die humanpathogenen Hantavirus-Spezies Puumalavirus (PUUV) und Dobravavirus (DOBV) vor. Infektionen mit dem PUUV führen zu milden klinischen Verläufen des HFRS, die auch als "Nephropathia epidemica" bezeichnet werden. Für das DOBV konnte in Mitteleuropa die sympatrische Existenz von 2 genetischen Linien, DOBV-Aa und DOB-Af, nachgewiesen werden, die von unterschiedlichen Nagetierwirten (Apodemus agrarius und A. flavicollis) getragen werden und möglicherweise unterschiedlich virulent für den Menschen sind. Chimäre Hepatitis B Virus-Corepartikel und Hefe-exprimiertes, rekombinantes PUUV-Nukleokapsid (N)-Protein stellen vielversprechende Impfstoffkandidaten dar, die in der Rötelmaus, dem natürlichen Wirt und Überträger des PUUV, eine schützende Immunantwort induzieren können. Eine hauptprotektive Determinante konnte im N-Protein des PUUV zwischen den Aminosäuren (AS) 1-45 lokalisiert werden; eine zweite, schwach protektive Determinante ist zwischen AS 75-119 lokalisiert. Die schwache Protektivität der 45 aminoterminalen AS des PUUV-N-Proteins (Stamm Vranica/Hällnäs) konnte durch Verwendung eines 120 AS-langen Segments deutlich verbessert werden. Ein Hefe-exprimiertes PUUV-N-Protein mit aminoterminalem Hexahistidinschwanz induzierte bei Verwendung von komplettem Freund´schen Adjuvans in allen vakzinierten Rötelmäusen eine schützende Immunität. Bei Verwendung von Aluminiumhydroxid, einem für humane Anwendungen zugelassenen Adjuvans, wurden alle immunisierten Tiere mindestens partiell, darunter 75 % der Tiere sogar komplett, vor einem nachfolgenden Viruschallenge geschützt. An der Induktion einer schützenden Immunität sind wahrscheinlich nicht nur zelluläre, sondern auch humorale N-Protein-spezifische Immunantworten beteiligt. / Human infections with European hantaviruses are associated with the "Haemorrhagic fever with renal syndrome" (HFRS), whereas North and South-American hantaviruses cause in human the "Hantavirus pulmonary syndrome". In Central Europe two hantavirus species, Puumala virus (PUUV) and Dobrava virus (DOBV), are pathogenic to human. PUUV infections result in milder clinical courses of HFRS, designated also as "Nephropathia epidemica". For DOBV the sympatric occurrence of two genetic lineages, DOBV-Aa and DOBV-Af, has been detected. These lineages are carried by two different rodent hosts (Apodemus agrarius and A. flavicollis) and might be of different pathogenicity to human. Chimaeric hepatitis B virus core particles and yeast-expressed recombinant PUUV nucleocapsid (N) protein are promising vaccine candidates. They are able to induce a protective immune response in bank voles, the natural host of PUUV. A major protective determinant has been localized between amino acids (aa) 1-45; a second, minor protective determinant is located between aa 75-119. The low protectivity of the 45 amino-terminal aa of the N protein of PUUV (strain Vranica/Hällnäs) can be overcome by the use of a larger, 120 aa-long segment of this N protein. A yeast-expressed PUUV N protein harboring an amino-terminal hexahistidin tag is able to induce a protective immunity in all immunized bank voles when applied with Freund´s complete adjuvant. Using alum, an adjuvant certified for human use, all immunized animals were protected at least partially, 75% even completely, against a subsequent virus challenge. Likely, the protective immunity is mediated not only by cellular but also by humoral immune responses against the N protein.

The thesis describes a completely new biofuel system to generate particle-free heat from combustion of ash-containing biofuel particles at high temperatures. The suggested system gives opportunities to introduce biofuels in new areas. Main components in the suggested system is a heat radiating combustion chamber intended for pulverized wood, combined with regenerators to extract heat from flue gases and simultaneously preheating the combustion air. The thesis contains a description of the suggested system, theoretical considerations, calculations regarding the combustion, and includes results from tests performed. The results from calculations and tests performed concludes that the system is workable and possible to apply. / Uppsatsen beskriver ett helt nytt system för att åstadkomma partikelfri värme och höga temperaturer från biobränslen. Det föreslagna systemet ger goda möjligheter att använda biobränslen inom helt nya områden. Systemet består huvudsakligen av en brännkammare för träpulver, utförd som en hålrumsstrålare, samt regenerativa värmeväxlare mellan avgående rökgas och inkommande förbränningsluft. Uppsatsen innehåller en beskrivning av det föreslagna systemet, teoretiska överväganden, beräkningar rörande förbränningen, samt redovisar resultat från gjorda försök. Resultat från beräkningar och genomförda försök visar att det föreslagna systemet fungerar och är praktiskt möjligt att tillämpa.

Poly(3,4-ethylenedioxythiophene), PEDOT, belongs to the group of conducting polymers and is characterized by its high stability, a moderate band gap and its optical transparency in the conductive state. A large disadvantage of conducting polymers, and also PEDOT, is their poor solubility. One way to achieve processible materials is the synthesis of colloidal particles. Thus, this work focuses on the development of conductive particles by preparing composite structures. Polymeric colloids like latex particles and microgels were used as templates for the oxidative polymerization of EDOT. Depending on template structure completely different composite morphologies with variable properties were obtained. It was found that modification with PEDOT did not only cause conductive particles for application as humidity sensor materials, but also candidates for further functionalization with gold nanoparticles (Au-NPs). Due to a multi-stage synthesis route it was possible to achieve polystyrene(core)-PEDOT(shell)-particles decored with Au-NPs. Microgels acting as “micro reactors” for the incorporation of PEDOT and Au-NPs were also used for preparing multifunctional composites for catalytic applications. / Poly(3,4-ethylendioxythiophen), PEDOT, gehört zur Gruppe der leitfähigen Polymere und zeichnet sich durch seine hohe Stabilität, eine moderate Bandlücke und seine optische Transparenz im dotierten Zustand aus. Ein Nachteil leitfähiger Polymere, wie auch von PEDOT, ist deren schlechte Löslichkeit. Die Synthese kolloidaler Partikel bietet jedoch eine Möglichkeit dieses Problem zu umgehen. In diesem Zusammenhang richtete sich der Fokus dieser Arbeit auf die Darstellung leitfähiger Partikel in Form von Kompositstrukturen. Polymerkolloide, wie Latex- und Mikrogelpartikel, sind als Template eingesetzt worden, in deren Gegenwart PEDOT durch eine oxidative Polymerisation synthetisiert wurde. In Abhängigkeit von der Struktur des Templats sind unterschiedliche Kompositmorphologien mit steuerbaren Eigenschaften erhalten worden. Auf diese Weise wurden neben Materialien für die Feuchtigkeitssensorik leitfähige Kompositpartikel hergestellt, die zusätzlich mit Gold-Nanopartikeln (Au-NP) funktionalisiert werden konnten. Durch ein mehrstufiges Syntheseverfahren sind somit Polystyrol(Kern)-PEDOT(Schale)-Partikel mit Au-NP-funktionalisierter Oberfläche synthetisiert worden. Mikrogelpartikel, die als „Mikroreaktoren“ für die Inkorporation von PEDOT- und Au-NP dienten, wurden ebenfalls eingesetzt, um multifunktionale Komposite mit katalytischen Eigenschaften herzustellen.

This research is focused on preparation of polypyrrole (PPy) composite particles by using socalled template oxidative polymerization method. As a template, water-soluble polymers, polymeric microgels, latex particles or bulk gels can be used. The morphology and properties of the composite particles can be controlled effectively by the proper use of the template. By choosing the dopant anion or oxidation agent it is possible to vary the conductivity of the polymer. In the case when uncrosslinked PVME was used as stabilizer, core-type polypyrrole spherical particles in the range of 50-100 nm were formed in both aqueous ethanol and water. Results of the elementary analysis, IR spectroscopy confirmed that the anionic salts can be incorporated in the PPy particles and play as the dopants. The presence of dopants in polypyrrole enhances the conductivity, especially in the case of sodium benzoate the conductivity of the final product has been improved by 3 orders. Polymeric microgels were also applied as the templates for polypyrrole deposition. When crosslinked PVME microgels were used in the oxidation polymerization of pyrrole, large PPy fibrils (appr. 400nm) were formed. Needle-like particles were formed due to the porous structure of microgels, which play a template role in the pyrrole polymerization process. When poly(VCL/AAEM) microgels were used as a template for oxidative polymerization of pyrrole, &amp;quot;raspberry-like&amp;quot; composite particles will be formed with PPy domains located in swollen hydropholic particle shell. Obtained stable composite microgels show similar thermal sensitivity as poly(VCL/AAEM) particles with fully reversible collapse-swelling properties. Increase of PPy content in composite particles increases conductivity of the composite material. The conductivity of composite particles prepared in water was much higher than that of prepared in water : ethanol mixtures. Furthermore, monodisperse PS-PEGMA particles, which were prepared in water medium by polymerization with sodium peroxydisulfate have been used as a template for deposition of polypyrrole (PPy). Obtained composite particles possess core-shell morphology where shell is composed out of small PPy nano-domains. The shell thickness can be varied by changing PPy load, controlling the overall template surface area in the system, and by influencing the pyrrole polymerization kinetics in presence of different oxidants. The last possibility provides also incorporation of different anions into polypyrrole shell. The stability of composite particles decreases gradually if the deposited PPy amount increases. It has been established that obtained particles are intrinsically coloured and the colour can be changed by the PS-PEGMA core size. Conductivity measurement shows that PS/PEGMA/PPy composite particles prepared by using phosphomolybdate as the oxidant are much more conductive than the particles prepared by the other two oxidants. The conductivity increases with the increase of PPy load in the system. Overall, the proper design of the template should give a possibility to control effectively the morphology, particle size and provide sufficient stability to the composite particles. Different morphologies, such as spherical, core-shell, raspberry and needle-like, with different particle size are expected to be available in different cases. By choosing the dopant anion or oxidation agent it is possible to vary the conductivity of the polymer. The stable water-based dispersions are expected to be used as additives for paint formulations, in electrorheology, microelectronic, ion-separation or disease diagnostics.

The Drosophila Lipoprotein particles bear lipid-linked morphogens on their surface and are required for long-range signaling activity of Wingless and Hedgehog. They also bind a wide variety of gpi-linked proteins. Whether any of these proteins affect morphogen signaling is unknown. Here, I show that the gpi-linked heparan sulfate proteoglycan Dally is released from cell membranes and binds to lipoprotein particles both with and without its lipid anchor. Hedgehog signaling efficiency is reduced in Dally mutant discs, but can be rescued non-autonomously by expression of non-gpi-modified Dally. This Dally isoform colocalizes with Hedgehog, Patched and Lipophorin in endosomes and increases Hedgehog signaling efficiency without affecting Hedgehog distribution. These data show that Hedgehog signaling activity can be influenced by other Lipophorin-associated proteins, and suggest Lipoproteins provide a platform for regulation of morphogen signaling.

Die vorliegende Arbeit mit dem Thema „Beitrag zur Entwicklung von Dieselrußpartikelfiltern“ zeigt die Entwicklung eines neuartigen Partikelfilterwerkstoffes vom Pulver bis zum Test des Bauteils am Motorenprüfstand. Die hohe Temperaturwechselbeständigkeit (TWB) des neu entwickelten feuerfesten Filtermaterials auf Basis von Al2O3-ZrO2-TiO2 (AZT) beruht auf der linearen Wärmedehnung in Kombination mit der Ausbildung einer Mikrorissstruktur sowie einem sehr niedrigen E-Modul von 8,5 GPa. Eine zusätzliche Kompensation von Wärmespannungen, welche aus der hohen Wärmedehnung von 7,5 · 10-6 K-1 der Tonerdematrix resultieren, erfolgt durch den modularen Aufbau des Wabenkörpers. Nicht zuletzt bewirkt die offene Porosität von 42% die verbesserte TWB. Durch die Verwendung von 95 Ma.% Al2O3 als Matrixwerkstoff ist der neu entwickelte AZT-Werkstoff für den Kontakt mit der Asche im für die Regeneration relevanten Temperaturbereich geeignet.

<p>The thesis describes a completely new biofuel system to generate particle-free heat from combustion of ash-containing biofuel particles at high temperatures.</p><p>The suggested system gives opportunities to introduce biofuels in new areas.</p><p>Main components in the suggested system is a heat radiating combustion chamber intended for pulverized wood, combined with regenerators to extract heat from flue gases and simultaneously preheating the combustion air.</p><p>The thesis contains a description of the suggested system, theoretical considerations, calculations regarding the combustion, and includes results from tests performed.</p><p>The results from calculations and tests performed concludes that the system is workable and possible to apply.</p> / <p>Uppsatsen beskriver ett helt nytt system för att åstadkomma partikelfri värme och höga temperaturer från biobränslen.</p><p>Det föreslagna systemet ger goda möjligheter att använda biobränslen inom helt nya områden.</p><p>Systemet består huvudsakligen av en brännkammare för träpulver, utförd som en hålrumsstrålare, samt regenerativa värmeväxlare mellan avgående rökgas och inkommande förbränningsluft.</p><p>Uppsatsen innehåller en beskrivning av det föreslagna systemet, teoretiska överväganden, beräkningar rörande förbränningen, samt redovisar resultat från gjorda försök.</p><p>Resultat från beräkningar och genomförda försök visar att det föreslagna systemet fungerar och är praktiskt möjligt att tillämpa.</p>