Lower respiratory diseases are currently the third leading cause of death worldwide. For many end-stage patients with these diseases, there is no cure and a shortage of donor organs available for transplant. A promising solution is to design regenerative scaffolds or complete bioengineered lungs, using decellularized lung tissues as a template for regeneration. Recent advances in the field have made significant strides towards developing a transplantable lung. However, the current technology has not produced a functional lung for in vivo transplant due to immature gas exchange barriers. The mechanisms driving alveolar barrier maturation and role that extracellular matrix (ECM) plays within the strengthening of each type of junction are not fully understood. This research has characterized and tailored a decellularized ECM (dECM) coating for the in vitro study of dECM component depletion and potential effects on cell barrier function, attachment, and survival. Adjustments to dECM digestion duration drastically changed the resulting structural and biochemical properties for each cellular microenvironment. Shorter digestion time resulted in a dense branching of the ECM architecture and biomimetic mechanical properties needed for epithelial culture. Also, through systematic supplementation of essential basement membrane (BM) proteins to dECM, we have found that supplementation with laminin enhanced barrier strength by ZO-1 junction stabilization. This indicates that dECM can promote barrier formation but may have lost vital proteins that need to be replenished. Laminin-mediated barrier function was determined to be caused by the upregulation of the Epac/Rap1 pathway. This pathway has previously been implicated in lung endothelial barriers but not alveolar epithelial junction strengthening. Finally, to establish the translatability of these findings to whole lung recellularization, the dECM coating was used to pre-treat the airways of decellularized lungs for recellularization. Culture of MLE12 mouse epithelial cells into dECM-coated lungs increased cell survival and distribution. In combination with dECM coatings, rotational cell seeding improved cell dispersal and viability. Altogether, these techniques, devised to promote healthy alveolar barriers, are vital to enhancing current lung recellularization strategies and the treatment of many edema-associated pulmonary diseases.

Pre-pubertal pig oocytes possess lower developmental competence than those from adult pigs following in vitro maturation (IVM). Previous studies have demonstrated that exposure of pre-pubertal oocytes to 1 mM dibutyryl cAMP (dbcAMP), a membrane permeable cyclic adenosine monophosphate (cAMP) analogue, for the first 20 h of IVM improves the rate of blastocyst development. Developmental competence of in vitro matured pig oocytes has been reported to increase with increasing follicle size. In this thesis, experiments were carried out using pre-pubertal and adult pig oocytes to investigate the relationship between donor age, intra-oocyte cAMP level and follicle size in terms of oocyte maturation and developmental competence. These experiments demonstrated that, while ovarian, follicular and oocyte morphology are immediately altered with the onset of puberty, pre-pubertal oocytes must be exposed to more than the first oestrous cycle to achieve improved developmental competence in vitro. Later experiments demonstrated that pre-pubertal oocytes accumulate less cAMP during IVM, undergo more rapid meiotic progression and display reduced rates of blastocyst development compared to in vitro matured adult oocytes. Treatment with dbcAMP for 22 h IVM increased the cAMP content of pre-pubertal oocytes, slowed meiotic progression during IVM and improved the rate of blastocyst formation. While the cAMP concentration of pre-pubertal oocytes was increased to levels similar to that of adult oocytes, rates of blastocyst formation remained lower, suggesting that additional factor(s) are required for oocyte maturation. This thesis also examined the follicle size cohorts that make up the 3-8 mm aspiration range on pig ovaries. The surface of pre-pubertal ovaries contained around double the number of 3 mm follicles compared with adult ovaries. Blastocyst development of pre-pubertal oocytes increased with increasing follicle size and was highest using oocytes from 5-8 mm follicles, while adult oocytes from all follicle size cohorts displayed similar high rates of blastocyst formation. The interaction between follicle size and cAMP content in pre-pubertal oocytes was examined next. Cumulus-oocyte complexes (COCs) from 3 mm follicles accumulated less intra-oocyte and inter-COC cAMP and displayed reduced cumulus expansion compared with COCs from 5-8 mm follicles. While dbcAMP treatment increased the cAMP content of oocytes from 3 mm follicles, it had no effect on the cAMP content of the whole COC. These findings suggest that inadequate levels of intra-oocyte cAMP during IVM contribute to the low developmental competence of pre-pubertal oocytes from 3 mm follicles, suggesting that cAMP transfer, production or degradation processes are incomplete. Analysis of steroid content from different follicle size cohorts revealed that the progesterone content of prepubertal follicular fluid (FF) increased with increasing follicle size, yet overall was lower than that of adults. This suggests that differences may exist in the gonadotropinstimulated steroidogenic activity of granulosa cells of pre-pubertal COCs from different follicle sizes. Since progesterone secretion did not differ between pre-pubertal and adult COCs, it appears that the downstream pathway from the granulosa cell response rather than the actual quantity of progesterone is important for subsequent maturation processes. These studies then examined gap junction communication (GJC) within the pre-pubertal COC during IVM to examine whether the positive effects of increasing follicle size and dbcAMP on intra-oocyte cAMP levels relates to improved cAMP transfer between the cumulus cell layer and oocyte. Cumulus cell-oocyte GJC during IVM was maintained for a longer period in pre-pubertal COCs from 3 mm follicles than in those from 5-8 mm follicles. Treatment with dbcAMP had minimal effect on GJC in either COC type, thus the dbcAMP-induced increase in intra-oocyte cAMP levels appears independent of GJC. Differences in GJC during IVM together with the COCs ability to increase intraoocyte cAMP levels during IVM, suggests that differences may exist in the quantity of gonadotropin receptors, which are responsible for cAMP production, within the cumulus layer of COCs from 3 mm compared with 5-8 mm follicles. In conclusion, this thesis has demonstrated that an increase in intra-oocyte cAMP is necessary during maturation for completion and synchronisation of maturation and high developmental competence of the pig oocyte. Comparison of 3, 4 and 5-8 mm follicle sizes in the pre-pubertal pig, as described here, provides an excellent model for further investigation into the role of cAMP and the other factors required for co-ordination of oocyte nuclear and cytoplasmic maturation and subsequent embryo production. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297309 / Thesis (Ph.D.) -- School of Paediatrics and Reproductive Health, 2007

<p>This thesis is concerned with employing the statistics of charge transfer in a conductor as a tool for quantum measurement. The physical systems studied are electronic devices made by nanoscale manufacturing techniques. In this context quantum measurement appears not as a postulate, but as physical process. In this thesis I am considering a quantum system, in particular a qubit or a nanomechanical resonator, interacting with a tunnel junction. The effect of coupling a quantum system to a tunnel junction is twofold: The state of the quantum system will be changed and there will be information about the quantum system in the statistics of charge transfer of the tunnel junction. As the first example a quantum measurement process of a qubit is considered. A common description of the system and charge dynamics is found by introducing a new quantity, the charge specific density matrix. By deriving and solving a Markovian master equation for this quantity the measurement process is analyzed. The measurement is shown to be a dynamical process, where correlations between the initial state of the qubit and the number of charges transferred in the tunnel junction arise on a typical timescale, the measurement time. As another example of a quantum system a nanomechanical oscillator is considered. It is found, that the biased tunnel junction, acting as a non-equilibrium environment to the oscillator, increases the temperature of the oscillator from its thermal equilibrium value. The current in the junction is modulated by the interaction with the oscillator, but the influence vanishes for bias voltages smaller than the oscillator frequency. For an asymmetric junction and non-vanishing oscillator momentum a current is shown to flow through the junction even at zero bias. The current noise spectrum induced by the oscillator in the tunnel junction consists of a noise floor and a peaked structure with peaks at zero frequency, the oscillator frequency and double the oscillator frequency. The peak heights are dependent on the coupling strength between oscillator and junction, the occupation number of the oscillator, the bias voltage and the junction temperature. I show how the peak height can be used as a measure of the oscillator temperature, demonstrating that the noise of a tunnel junction can be used for electronic thermometry of a nanomechanical oscillator.</p>

<p>Antisense RNAs regulate gene expression in many bacterial systems. The best characterized examples are from prokaryotic accessory elements such as phages, plasmids and transposons. Many of these antisense RNAs have been identified as plasmid copy number regulators where they regulate the replication frequency of the plasmid by negative feedback. Instability and fast binding kinetics is crucial for the regulatory efficiency of these antisense RNAs. </p><p>In this thesis, the interaction of the cis-encoded antisense RNA CopA with its target CopT was studied in detail using <i>in vivo</i> reporter gene fusion expression and different <i>in vitro </i>methods, such as surface plasmon resonance, fluorescence resonance energy transfer, and gel-shift assays.</p><p>Formation of inhibitory complexes differs from simple hybridization reactions between complementary strands. E.g., the binding pathway of CopA and CopT proceeds through a hierarchical order of steps. It initiates by reversible loop-loop contacts, resulting in a helix nucleus of two or three base pairs. This is followed by rapid unidirectional helix progression into the upper stems, resulting in a four-way helical junction structure. It had been suggested that the loop of CopT carries a putative U-turn, a structure first found in tRNA anticodon loops. We showed that this putative U-turn is one of the structural elements of CopA/CopT required to achieve fast binding kinetics. Furthermore, the hypothetical U-turn structure determines the direction of helix progression when the kissing complex progresses to a four-way helical junction structure. Another structural element in CopT is the helical stem adjacent to the recognition loop. This stem is important to present the recognition loop appropriately to provide a scaffold for the U-turn.</p><p>Furthermore, the role of protein Hfq in the interaction of antisense/target RNA was investigated, since several trans-encoded antisense RNAs had been shown to need this protein to exert their function. In contrast, studies of two cis-encoded antisense RNA systems showed that these antisense RNAs do not rely on Hfq for activity. In this study it was also shown that MicF, a trans-encoded antisense RNA which is dependent on Hfq, is greatly stabilized by this protein.</p>

In the next decade, technology trends--smaller dimension, lower voltage, higher operating frequency--introduce new technical considerations and challenges for radiation effects in integrated circuits. Semiconductor based circuits and traditional dynamic random-access memories will malfunction when exposed to extreme environments, such as space and nuclear reactor. The mechanisms for radiation effect are mainly attributed to the radiation-induced charging of the oxide in a CMOS device. Spintronics is an emerging area of nanoscale electronics involving the detection and manipulation of electron spin. The magnetic tunnel junctions (MTJs), based on the intrinsic spin of the electron, can be used as the storage elements in non-volatile magnetoresistive random-access memories (MRAMs). In this effort, we study radiation tolerance of MTJs by exposing the devices in gamma and neutron radiation environment. Theoretical model for the radiation-induced defects is analyzed in this work. Experiments of the MgO-based MTJs under the conditions of pre- and post-radiation are concluded. MTJs were irradiated with gamma ray to a total dose of 10 Mrad. During the neutron irradiation, total epithermal neutron fluence up to 2.9��10�����/cm�� was obtained. The experimental results show that neither the electrical nor the magnetic properties of MTJs are affected by the radiation. / Graduation date: 2013 / Access restricted to OSU community at author's request from Sept. 11, 2012 - Sept. 11, 2014

Junctions are the intersection points of three or more intensity surfaces in an image. An analysis of zero crossings and the gradient near junctions demonstrates that gradient-based edge detection schemes fragment edges at junctions. This fragmentation is caused by the intrinsic pairing of zero crossings and a destructive interference of edge gradients at junctions. Using the previous gradient analysis, we propose a junction detector that finds junctions in edge maps by following gradient ridges and using the minimum direction of saddle points in the gradient. The junction detector is demonstrated on real imagery and previous approaches to junction detection are discussed.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 147-163).

Im Rahmen dieser Arbeit wurden zwei humane Varianten des von Wang et al., 1999, erstmals beschriebenen muskelspezifischen Proteins Xin (Huhn und Maus) über Sequenzanalyse, Immunofluoreszenzmikroskopie, Transfektionsstudien und biochemischer Analyse näher charakterisiert. <br /> Die Proteine wurden mit human Xin related proteins 1 und 2 – hXirp1 und 2 –bezeichnet. Die Xin-Proteine enthielten bisher unbekannte, sowie spezifische, repetitive Motive, die aus jeweils mindestens 16 Aminosäuren bestanden. Ihre Aminosäuresequenz, mit einer Vielzahl weiterer putativer Motivsequenzen, verwies auf eine potentielle Funktion von hXirp als Adapterprotein in Muskelzellen. Das hier näher untersuchte hXirp1 lokalisierte an den Zell-Matrix-Verbindungen der Muskel-Sehnen-Übergangszone im Skelettmuskel, sowie an den Zell-Zell-Verbindungen der Glanzstreifen im Herzmuskel. Während der Muskelentwicklung zeigte hXirp1 eine sehr frühe Expression, zusammen mit einer prägnanten Lokalisation an den Prämyofibrillen und deren Verankerungsstrukturen, die auf eine Funktion des Proteins in der Myofibrillogenese deuten. Ektopische Expressionen von hXirp1 in einer Vielzahl von Nichtmuskel-Kulturzellen zeigten wiederum eine Lokalisation des Proteins an den Zell-Matrix-Kontakten dieser Zellen. Am Beispiel von hXirp1 und 2 wurde stellvertretend für die Familie der Xin-Proteine gezeigt, daß es sich bei den repetitiven Motiven um neuartige, F-Aktin bindende Sequenzmotive handelte. Die Xin-Proteine können somit als muskelspezifische, aktinbindende, potentielle Adapterproteine bezeichnet werden, denen eine strukturelle und funktionelle Beteiligung an der Verankerung der Myofibrillen im adulten Muskel, wie auch während der Myofibrillogenese zukommt. / The scope of this work was a further characterization of two human variants of the protein Xin which was reported for chicken and mouse in 1999 by Wang et al. Therefor sequence analysis, immunofluorescence microscopy, transfection studies and biochemical approaches were utilized.<br /> The proteins were named human Xin related proteins 1 und 2 – hXirp1 und 2. Xin-proteins possess specific repetitive motives consisting of a minimum of 16 amino acids each. Concerning further putative motive sequences hXirp is a potential adapter protein in the muscle cell. hXirp1 localized within the cell-matrix-contacts of the myotendinous junction in skeletal muscle as well as within the cell-cell-contacts of the intercalated disc in the cardiac muscle. During the development of muscle cells hXirp1 showed early expression as well as concise localization to premyofibrils and their anchorage structures indicating a potential role for this protein in myofibrillogenesis. Ectopic expression of hXirp1 in several non-muscle cells again revealed localization of this protein to cell-matrix contacts. Considering hXirp1 and 2 as an example for all Xin-proteins it was shown that the repetitive motives are new actin binding motives. The data indicated the Xin-proteins as muscle specific, actin binding and potential adapter proteins with implications in structure and function of anchorage of myofibrils in adult muscle and myofibrillogenesis.

Electronic components, based on current semiconductor technologies and operating in radiation rich environments, suffer degradation of their performance as a result of radiation exposure. Silicon carbide (SiC) provides an alternate solution as a radiation hard material, because of its wide bandgap and higher atomic displacement energies, for devices intended for radiation environment applications. However, the radiation tolerance and reliability of SiC-based devices needs to be understood by testing devices  under controlled radiation environments. These kinds of studies have been previously performed on diodes and MESFETs, but multilayer devices such as bipolar junction transistors (BJT) have not yet been studied. In this thesis, SiC material, BJTs fabricated from SiC, and various dielectrics for SiC passivation are studied by exposure to high energy ion beams with selected energies and fluences. The studies reveal that the implantation induced crystal damage in SiC material can be partly recovered at relatively low temperatures, for damag elevels much lower than needed for amorphization. The implantation experiments performed on BJTs in the bulk of devices show that the degradation in deviceperformance produced by low dose ion implantations can be recovered at 420 oC, however, higher doses produce more resistant damage. Ion induced damage at the interface of passivation layer and SiC in BJT has also been examined in this thesis. It is found that damaging of the interface by ionizing radiation reduces the current gain as well. However, for this type of damage, annealing at low temperatures further reduces the gain. Silicon dioxide (SiO2) is today the dielectric material most often used for gate dielectric or passivation layers, also for SiC. However, in this thesis several alternate passivation materials are investigated, such as, AlN, Al2O3 and Ta2O5. These materials are deposited by atomic layer deposition (ALD) both as single layers and in stacks, combining several different layers. Al2O3 is further investigated with respect to thermalstability and radiation hardness. It is observed that high temperature treatment of Al2O3 can substantially improve the performance of the dielectric film. A radiation hardness study furthermore reveals that Al2O3 is more resistant to ionizing radiation than currently used SiO2 and it is a suitable candidate for devices in radiation rich applications. / QC 20120117

This thesis focuses on theoretical study of charge transportproperties in molecular systems. The understanding of the transportprocess and mechanism in molecular systems is essential forthe design of new functional molecular materials and molecularelectronic devices. The molecular junctions and organic molecularcrystals have been used as the model systems to highlight the usefulnessof theoretical modelling. A molecular junction is a system that consists ofone or several molecules sandwiched between two electrodes.The charge transport in molecular junctions is a very complex processthat is affected by the interaction between molecules and electrodes,the surroundings, as well as electron-electron (e-e) andelectron-phonon (e-p) couplings. When the molecule-electrode couplingis strong, the transport process can be very quick. If the e-p couplingis weak, the inelastic tunneling has only negligible contributions to thetotal current and the elastic electron tunneling plays the dominant role.Furthermore, the hopping process becomes dominant in the case of strong e-pcoupling, for which the geometric relaxation of the molecule needsto be considered. In this thesis, we have examined these three kinds oftransport processes separately. The first studied system is a molecular junction consisting of aromaticallycoupled bimolecules. Its elastic electron tunneling property is simulatedusing Green's functional theory at density functional theory level.The dependence of the conductance of bimolecular junctions on the vertical distances,horizontal distances and the tilt angles has been systematically studied. Theinelastic electron tunneling spectra (IETS) of molecular junctions have beencalculated for several systems that were experimentally measured with conflictingresults and controversial assignments. Our calculations provide the reliableassignments for the experimental spectra and revealed unprecedented detailsabout the molecular conformations within the junctions under different conditions.It demonstrates that a combined theoretical and experimental IETS study is capableof accurately determining the structure of a single molecule inside the junction.The hopping process is a dominant charge transfer process in organic molecularcrystals. We have studied the charge transport ability of four kinds of n-typeorganic semiconductor materials to find out the related structure-to-propertyrelationship. It is done by adopting the quantum charge transfer rate equationcombined with the random walk approach. / QC 20120515