Differenzielle Expression von Proteinen im Glaskörper gesunder und an ERU erkrankter Pferde

Die equine rezidivierende Uveitis (ERU) ist die häufigste Augenerkrankung bei Equiden. Die pathogenetischen Mechanismen, die den rezidivierenden immunologisch-inflammatorischen Reaktionen und der Schädigung intraokularer Strukturen zu Grunde liegen, sind weitgehend unerforscht. Ziel dieser Arbeit war es, durch die Kombination von zweidimensionaler Gelelektrophorese und massenspektrometrischen Untersuchungen, die Proteinexpression in den Glaskörpern gesunder und an ERU erkrankter Pferde zu analysieren und durch die Identifizierung differenziell exprimierter Proteine, Hinweise auf Mechanismen zu erhalten, die bei der Pathogenese der ERU von Bedeutung sind. Dabei wurde Material verwendet, das bei der therapeutischen Pars-plana-Vitrektomie chirurgisch entfernt wird, was zu einer Reduktion weiterer Schübe führt. Deutliche Unterschiede zwischen gesunden und uveitischen Augen zeigten sich bereits in einer signifikant erhöhten Proteinkonzentration der Glaskörper uveitischer Pferde (3,67 µg/µl ± 2,28 µg/µl bei ERU im Vergleich zu 0,15 µg/µl ± 0,05 µg/µl bei gesunden). Die nach zweidimensionaler Gelelektrophorese des Glaskörpermaterials erhaltenen Proteinmuster der Glaskörper gesunder Augen waren sehr homogen. Ebenso zeigten die Proteinmuster der uveitischen Glaskörper untereinander nur geringe individuelle Unterschiede. Deutliche Unterschiede in der Proteinexpression waren jedoch beim Vergleich von Glaskörpern gesunder und uveitischer Augen festzustellen. Nach massenspektrometrischer Analyse der zweidimensional aufgetrennten Proteine wurden insgesamt elf differenziell exprimierte Proteine identifiziert. Hiervon waren in den Glaskörpern uveitischer Pferde, im Vergleich zu gesunden, sechs Proteine (Albumin, Gamma-Immunglobulin, Komplement C3, Apolipoprotein-AI, Carboxylesterase D1 und Histone deacetylase complex subunit SAP18) höher und fünf Proteine (Plasma Retinol-bindendes Protein, Prostaglandin-H2 D-isomerase, Dickkopf-related protein 3, Secreted frizzled-related protein 2 und Pigment epithelium-derived factor) niedriger exprimiert. Diese differenziell exprimierten Proteine sind im Zusammenhang mit der Blut-Retina-Schranke, mit Immunantworten und der Modulation des Wnt-Signalweges von Bedeutung. Interessant ist insbesondere eine mögliche Beteiligung des Wnt-Signalweges bei der ERU. Dieser wurde im Zusammenhang mit Uveitiden bisher nicht beschrieben. Die signifikant reduzierte Expression konnte für sFRP-2 und PEDF darüber hinaus direkt im retinalen Gewebe gezeigt werden. Dabei konnte zusätzlich ein Zusammenhang zwischen niedrigem PEDF und auftretender VEGF-Expression in der Netzhaut nachgewiesen werden. Die Proteomanalyse hat sich somit als geeignetes Instrument bei der Identifizierung neuer, möglicherweise bei der Pathogenese der ERU relevanter, Proteine und biologischer Signalwege erwiesen

Scanning Acoustic GHz-Microscopy in Microelectronics Failure Analysis

The ongoing trend in microelectronics aims at increasing functionality while reducing the devices footprint. This leads to the currently highly pursued approach of three-dimensional integration of individual devices with e.g. sensors and application specific integrated circuitry resulting in highly integrated and complex systems. By extending the system structure to the third spatial dimension, the aim of chip-to-wafer or wafer-to-wafer bonding techniques is no longer restricted to mechanical integration only. Techniques like adhesive bonding, Cu/Cu thermo-compression bonding or hybrid bonding have also to provide a precise formation of robust and reliable vertical electrical interconnects within the bonding interface. Furthermore, the interaction of Through-Silicon-Via technology (TSV) that enables an efficient 3D-distribution concept with the bonding technologies have to be taken into account. As a consequence, these new technological concepts lead to new defect risks which require novel and adapted inspection methods for assessing quality-related properties and understanding the physical relationship. Today scanning acoustic microscopy (SAM) is already widely used in quality control and failure analysis applications within microelectronics development and manufacturing. The technique is particularly sensitive to material boundaries for the assessment of quality- and reliability- affecting factors like voids and inclusions, cracks, delamination, bonding defects, and many more [1]. Since 3D-integration technologies result in reduced spatial dimensions of the electrical and mechanical interconnects and, thus smaller defects, the demand on the resolution capabilities of potential inspection techniques increases. The successful application of SAM in 3D integration however, requires overcoming limitations in the achievable spatial resolution and the integration of adapted SAM analysis technologies for vertical contacts. The current paper presents the relatively novel approach of applying acoustic microscopy in the GHz-frequency band to increase the achievable lateral resolution and the sensitivity to surface and near-surface features with resolutions in the 1 μm regime. The potential of the GHz-SAM approach will be illustrated describing the inspection of Cu-Cu interfaces in mono-metallic wire bond systems [2] and the detection and propagation-assessment of stress induced voids in thick Al-power lines for high-temperature applications. Using short focal-length transducers GHz-SAM was also applied for the detection of delaminations in sub-surface electrical lines and the detection of cracks in the passivation layer of an RFID chip and the cracks sub-surface propagation. Finally, preliminary results of on-going research addressing the inspection of Through-Silicon-Vias will be presented and discussed

Equine recurrent uveitis - A spontaneous horse model of uveitis

Equine recurrent uveitis (ERU) is an autoimmune disease that occurs with a high prevalence (10%) in horses. ERU represents the only reliable spontaneous model for human autoimmune uveitis. We already identified and characterized novel autoantigens (malate dehydrogenase, recoverin, CRALBP) by analyzing the autoantibody-binding pattern of horses affected by spontaneous recurrent uveitis (ERU) to the retinal proteome. CRALBP also seems to be relevant to human autoimmune uveitis. Proteomic screening of vitreous and retinal samples from ERU diseased cases in comparison to healthy controls has led to the identification of a series of differentially regulated proteins, which are functionally linked to the immune system and the maintenance of the blood-retinal barrier. Copyright (c) 2008 S. Karger AG, Basel

The class V myosin motor protein, Myo2, plays a major role in mitochondrial motility in Saccharomyces cerevisiae

The actin cytoskeleton is essential for polarized, bud-directed movement of cellular membranes in Saccharomyces cerevisiae and thus ensures accurate inheritance of organelles during cell division. Also, mitochondrial distribution and inheritance depend on the actin cytoskeleton, though the precise molecular mechanisms are unknown. Here, we establish the class V myosin motor protein, Myo2, as an important mediator of mitochondrial motility in budding yeast. We found that mutants with abnormal expression levels of Myo2 or its associated light chain, Mlc1, exhibit aberrant mitochondrial morphology and loss of mitochondrial DNA. Specific mutations in the globular tail of Myo2 lead to aggregation of mitochondria in the mother cell. Isolated mitochondria lacking functional Myo2 are severely impaired in their capacity to bind to actin filaments in vitro. Time-resolved fluorescence microscopy revealed a block of bud-directed anterograde mitochondrial movement in cargo binding–defective myo2 mutant cells. We conclude that Myo2 plays an important and direct role for mitochondrial motility and inheritance in budding yeast

Mdm31 and Mdm32 are inner membrane proteins required for maintenance of mitochondrial shape and stability of mitochondrial DNA nucleoids in yeast

The MDM31 and MDM32 genes are required for normal distribution and morphology of mitochondria in the yeast Saccharomyces cerevisiae. They encode two related proteins located in distinct protein complexes in the mitochondrial inner membrane. Cells lacking Mdm31 and Mdm32 harbor giant spherical mitochondria with highly aberrant internal structure. Mitochondrial DNA (mtDNA) is instable in the mutants, mtDNA nucleoids are disorganized, and their association with Mmm1-containing complexes in the outer membrane is abolished. Mutant mitochondria are largely immotile, resulting in a mitochondrial inheritance defect. Deletion of either one of the MDM31 and MDM32 genes is synthetically lethal with deletion of either one of the MMM1, MMM2, MDM10, and MDM12 genes, which encode outer membrane proteins involved in mitochondrial morphogenesis and mtDNA inheritance. We propose that Mdm31 and Mdm32 cooperate with Mmm1, Mmm2, Mdm10, and Mdm12 in maintenance of mitochondrial morphology and mtDNA

Simple Applications of q-Bosons

A deformation of the harmonic oscillator algebra associated with the Morse potential and the SU(2) algebra is derived using the quantum analogue of the anharmonic oscillator. We use the quantum oscillator algebra or $q$-boson algebra which is a generalisation of the Heisenberg-Weyl algebra obtained by introducing a deformation parameter $q$. Further, we present a new algebraic realization of the $q$-bosons, for the case of $q$ being a root of unity, which corresponds to a periodic structure described by a finite-dimensional representation. We show that this structure represents the symmetry of a linear lattice with periodic boundary conditions.Comment: LATEX2e, 10 pages, v2: few misprints corrected, added Journal-re

Analysis of Mechanical Strain in AlGaN/GaN HFETs

Herein, the influence of mechanical strain induced by passivation layers on the electrical performance of AlGaN/GaN heterostructure field-effect transistor is investigated. We studied the physical mechanism of a threshold voltage (Vth) shift for the monolithically fabricated on/off devices reported earlier by our group. For that, theoretical calculations, simulation-based analysis, and nano-beam electron diffraction (NBED) measurements based on STEM are used. Strain distribution in the gate vicinity of transistors is compared for a SiNx passivation layer with intrinsic stress from ≈0.5 to −1 GPa for normally on and normally off devices, respectively. The strain in epitaxial layers transferred by intrinsic stress of SiNx is quantitatively evaluated using NEBD method. Strain dissimilarity Δε = 0.23% is detected between normally on and normally off devices. Using this method, quantitative correlation between 1.13 V of Vth shift and microscopic strain difference in the epitaxial layers caused by 1.5 GPa intrinsic stress variation in passivation layer is provided. It is showed in this correlation that about half of the reported threshold voltage shift is induced by strain, i.e., by the piezoelectric effect. The rest of Vth shift is caused by the fabrication process. Therefore, various components/mechanisms contributing to the measured Vth shift are distinguished

Multiscale microstructures and microstructural effects on the reliability of microbumps in three-dimensional integration

The dimensions of microbumps in three-dimensional integration reach microscopic scales and thus necessitate a study of the multiscale microstructures in microbumps. Here, we present simulated mesoscale and atomic-scale microstructures of microbumps using phase field and phase field crystal models. Coupled microstructure, mechanical stress, and electromigration modeling was performed to highlight the microstructural effects on the reliability of microbumps. The results suggest that the size and geometry of microbumps can influence both the mesoscale and atomic-scale microstructural formation during solidification. An external stress imposed on the microbump can cause ordered phase growth along the boundaries of the microbump. Mesoscale microstructures formed in the microbumps from solidification, solid state phase separation, and coarsening processes suggest that the microstructures in smaller microbumps are more heterogeneous. Due to the differences in microstructures, the von Mises stress distributions in microbumps of different sizes and geometries vary. In addition, a combined effect resulting from the connectivity of the phase morphology and the amount of interface present in the mesoscale microstructure can influence the electromigration reliability of microbumps

Multiscale microstructures and microstructural effects on the reliability of microbumps in three-dimensional integration

The dimensions of microbumps in three-dimensional integration reach microscopic scales and thus necessitate a study of the multiscale microstructures in microbumps. Here, we present simulated mesoscale and atomic-scale microstructures of microbumps using phase field and phase field crystal models. Coupled microstructure, mechanical stress, and electromigration modeling was performed to highlight the microstructural effects on the reliability of microbumps. The results suggest that the size and geometry of microbumps can influence both the mesoscale and atomic-scale microstructural formation during solidification. An external stress imposed on the microbump can cause ordered phase growth along the boundaries of the microbump. Mesoscale microstructures formed in the microbumps from solidification, solid state phase separation, and coarsening processes suggest that the microstructures in smaller microbumps are more heterogeneous. Due to the differences in microstructures, the von Mises stress distributions in microbumps of different sizes and geometries vary. In addition, a combined effect resulting from the connectivity of the phase morphology and the amount of interface present in the mesoscale microstructure can influence the electromigration reliability of microbumps

A Polynomial Spectral Calculus for Analysis of DG Spectral Element Methods

We introduce a polynomial spectral calculus that follows from the summation by parts property of the Legendre-Gauss-Lobatto quadrature. We use the calculus to simplify the analysis of two multidimensional discontinuous Galerkin spectral element approximations