International round-robin experiment for angle-resolved light scattering measurement

International audienc

Transcriptome profiling of ontogeny in the acridid grasshopper Chorthippus biguttulus

Acridid grasshoppers (Orthoptera:Acrididae) are widely used model organisms for developmental, evolutionary, and neurobiological research. Although there has been recent influx of orthopteran transcriptomic resources, many use pooled ontogenetic stages obscuring information about changes in gene expression during development. Here we developed a de novo transcriptome spanning 7 stages in the life cycle of the acridid grasshopper Chorthippus biguttulus. Samples from different stages encompassing embryonic development through adults were used for transcriptomic profiling, revealing patterns of differential gene expression that highlight processes in the different life stages. These patterns were validated with semi-quantitative RT-PCR. Embryonic development showed a strongly differentiated expression pattern compared to all of the other stages and genes upregulated in this stage were involved in signaling, cellular differentiation, and organ development. Our study is one of the first to examine gene expression during post-embryonic development in a hemimetabolous insect and we found that only the fourth and fifth instars had clusters of genes upregulated during these stages. These genes are involved in various processes ranging from synthesis of biogenic amines to chitin binding. These observations indicate that post-embryonic ontogeny is not a continuous process and that some instars are differentiated. Finally, genes upregulated in the imago were generally involved in aging and immunity. Our study highlights the importance of looking at ontogeny as a whole and indicates promising directions for future research in orthopteran development

Interleukin 6 Accelerates Mortality by Promoting the Progression of the Systemic Lupus Erythematosus-Like Disease of BXSB. Yaa Mice

IL6 is a multifunctional cytokine that drives terminal B cell differentiation and secretion of immunoglobulins. IL6 also cooperates with IL21 to promote differentiation of CD4(+) T follicular helper cells (TFH). Elevated serum levels of IL6 correlate with disease flares in patients with systemic lupus erythematosus (SLE). We previously reported that IL21 produced by T-FH plays a critical role in the development of the SLE-like disease of BXSB. Yaa mice. To examine the possible contributions of IL6 to disease, we compared disease parameters in IL6-deficient and IL6-competent BXSB. Yaa mice. We report that survival of IL6-deficient BXSB. Yaa mice was significantly prolonged in association with significant reductions in a variety of autoimmune manifestations. Moreover, B cells stimulated by co-engagement of TLR7 and B cell receptor (BCR) produced high levels of IL6 that was further augmented by stimulation with Type I interferon (IFN1). Importantly, the frequencies of T-FH and serum levels of IL21 were significantly reduced in IL6-deficient mice. These findings suggest that high-level production of IL6 by B cells induced by integrated signaling from the IFN1 receptor, TLR7 and BCR promotes the differentiation of IL21-secreting T-FH in a signaling sequence that drives the lethal autoimmune disease of BXSB. Yaa mice.Peer reviewe

Table top system for angle resolved light scattering measurement

Die Messung und Analyse von Streulicht hat in den vergangenen Jahren wesentlich an Einfluss gewonnen. Der Mangel an Messsystemen die sowohl flexibel als auch kompakt sind, motivierte diese Arbeit zur Entwicklung eines winkelauflösenden Table-Top Streulichtmesssystems mit dazugehörigen Auswertemethodiken.Das realisierte Table-Top Goniometer weist kompakte Abmaße von <0,8x0,8x0,8 m³ auf und ermöglicht die Messung von 3D-Streulichtverteilungen bei Beleuchtungwellenlängen von 405 nm, 532 nm und 640 nm. Mit erreichten Sensitivitäten, die nur durch die Luftstreuung begrenzt sind, wurde eine Dynamik von 14 Größenordnungen erzielt. Die kompakte Konstruktion wurde durch ein spezielles Achsdesign und über Faltung der Strahlengänge erreicht. Messunsicherheit und Instrumentesignatur wurden anhand von neu entwickelten Modellen und Simulationen analysiert. Darauf aufbauend erfolgten Optimierungen.Basierend auf dem Frequenzmultiplex-Prinzip wurde ein Konzept zur Ermöglichung paralleler Streulichtmessungen mit hoher Sensitivität und Dynamik entwickelt. Hiermit lässt sich das gestreute Licht unterschiedlicher Beleuchtungswellenlängen und/oder -polarisationen in verschiedenen Messkanälen gleichzeitig detektieren.Es wurde eine streulichtbasierte Analysemethode anisotroper Oberflächen eingeführt, die einen direkten Bezug zu optischen und rauheitsbeschreibenden Eigenschaften aufweist. Hiermit ließen sich erstmals Rauheitskomponenten unterschiedlicher Ursache bei ultrapräzisionsbearbeiteten diamantgedrehten Oberflächen als Funktion der Ortsfrequenz trennen. Der Einfluss von Anisotropie bei unterschiedlichen Beleuchtungswellenlängen wurde untersucht.Über Streulichtanalyse mit mehreren Beleuchtungswellenlängen wurde eine hochrobuste Rauheitscharakterisierung demonstriert. Hiermit ließen sich Kontaminationen auf beschichteten und unbeschichteten Substraten sowie Rauheitswachstum in Dünnschichtfilmen nachweisen.Es wurde gezeigt, dass sich Diamantschliffe über die Auswertung von 3D-Streulichtverteilungen charakterisieren lassen. Es können beispielsweise die Politurgüte einzelner Facetten sowie die optische Performance von Brillanten bewertet und klassifiziert werden.In the last decades, the measurement and analysis of scattered light gained importance. The lack of compact, yet comprehensive tools motivated this thesis to develop a highly universal table top instrument for angle resolved light scattering (ARS) measurement, as well as according measurement and analysis techniques.A table top scatterometer with a compact footprint of 0.8x0.8 m² is described. It enables full 3D spherical detection at illumination wavelengths of 405 nm, 532 nm, and 640 nm. With sensitivities limited only by Rayleigh scattering at air molecules, a dynamic range of 14 orders of magnitude was achieved. The compact layout of the scatterometer was realized by a specific arrangement of the axes where the optical path lengths are artificially increased by beam folding mirrors. The realized instrument is validated by a comprehensive performance analysis focused on instrument signature and measurement uncertainty. Corresponding optimizations are derived by means of simulations and analytic models.Based on frequency division multiplexing, a concept is proposed that enables wavelength and/or polarization multiplexed ARS measurements. It allows parallel ARS measurements over the complete dynamic range and with high sensitivity.A new quantity for anisotropy is introduced which is spatial frequency resolving and directly linked to scattering losses and roughness properties. It is utilized to discriminate four roughness components in ultra-precision diamond turned surfaces by 3D-ARS measurements. The impact of anisotropy as a function of the illumination wavelength is analyzed.Experiments at three illumination wavelengths are conducted to provide highly relatable roughness information. The analysis is used to detect contamination on coatings and substrates, as well as to analyze roughness growth on thin film layers.3D-ARS measurements are demonstrated to be capable of characterizing diamond cuts in all grading relevant categories. It is shown that light scattering analysis has a direct access to the optical performance of gemstone. A method is proposed that allows one to assess the polish of the individual facets from 3D-ARS measurements

Parallelized multichannel BSDF measurements

The intensity of scattered light is extremely sensitive to even small changes of illumination wavelength, incident angle, polarization states, or even the measurement position. To obtain light scattering distributions with varied parameters, time-consuming sequential measurement procedures are typically employed. Here, we propose a concept for the measurement of multiple properties at the same time. This is achieved by tailoring orthogonal frequency division multiplexing (OFDM) for light scattering measurement techniques to the required low interchannel crosstalk performance. The concept is used for a highly-robust roughness and contamination characterization, to derive one-shot roughness information, as well as to characterize color and appearance

New light absorbing material for grazing angles

One of the largest challenges for optical systems is eliminating stray light generated by reflections off the walls and other optical elements of the device. Most black coatings are not sufficiently effective at grazing angles. Acktar's black coatings exhibit particularly low residual reflectance and have been implemented in various instruments. The new proposed material exhibits particularly low hemispherical and specular reflectance-especially at grazing angles

Reducing light scattering from surface contaminations by thin film design

In most applications, contamination of optical thin film coatings is inevitable over time. State-of-The art approaches to tackle this problem are usually based on two strategies-avoiding contamination or removing already existing contamination. We demonstrate that the coating design can be tailored to reduce light scattering and stray light arising from particle contamination. This allows reducing the optical symptoms (light scattering) rather than trying to address the inevitable cause of the problem (contamination) itself. This new approach can consequently be easily combined with state-of-The-Art approaches

Vane-free design for star trackers and telescopes

Stray light is a significant issue in optical design and can dramatically influence the performance of the optical system

Light scattering techniques for the characterization of optical components

The rapid developments in optical technologies generate increasingly higher and sometimes completely new demands on the quality of materials, surfaces, components, and systems. Examples for such driving applications are the steadily shrinking feature sizes in semiconductor lithography, nanostructured functional surfaces for consumer optics, and advanced optical systems for astronomy and space applications. The reduction of surface defects as well as the minimization of roughness and other scatter-relevant irregularities are essential factors in all these areas of application. Quality-monitoring for analysing and improving those properties must ensure that even minimal defects and roughness values can be detected reliably. Light scattering methods have a high potential for a non-contact, rapid, efficient, and sensitive determination of roughness, surface structures, and defects