Analytical modeling and 3D finite element simulation of line edge roughness in scatterometry

The influence of edge roughness in angle resolved scatterometry at periodically structured surfaces is investigated. A good description of the radiation interaction with structured surfaces is crucial for the understanding of optical imaging processes like, e.g. in photolithography. We compared an analytical 2D model and a numerical 3D simulation with respect to the characterization of 2D diffraction of a line grating involving structure roughness. The results show a remarkably high agreement. The diffraction intensities of a rough structure can therefore be estimated using the numerical simulation result of an undisturbed structure and an analytically derived correction function. This work allows to improve scatterometric results for the case of practically relevant 2D structures

Effect of extracranial lesion severity on outcome of endovascular thrombectomy in patients with anterior circulation tandem occlusion: analysis of the TITAN registry

Introduction Endovascular treatment (EVT) for tandem occlusion (TO) of the anterior circulation is complex but effective. The effect of extracranial internal carotid artery (EICA) lesion severity on the outcomes of EVT is unknown. In this study we investigated the effect of EICA lesion severity on the outcomes of tandem occlusion EVT. Methods A multicenter retrospective TITAN (Thrombectomy In TANdem lesions) study that included 18 international endovascular capable centers was performed. Patients who received EVT for atherosclerotic TO with or without EICA lesion intervention were included. Patients were divided into two groups based on the EICA lesion severity (high-grade stenosis (>= 90% North American Symptomatic Carotid Endarterectomy Trial) vs complete occlusion). Outcome measures included the 90-day clinical outcome (modified Rankin Scale score (mRS)), angiographic reperfusion (modified Thrombolysis In Cerebral Ischemia (mTICI) at the end of the procedure), procedural complications, and intracranial hemorrhage at 24 hours follow-up. Results A total of 305 patients were included in the study, of whom 135 had complete EICA occlusion and 170 had severe EICA stenosis. The EICA occlusion group had shorter mean onset-to-groin time (259 +/- 120 min vs 305 +/- 202 min;p=0.037), more patients with diabetes, and fewer with hyperlipidemia. With respect to the outcome, mTICI 2b-3 reperfusion was lower in the EICA occlusion group (70% vs 81%;p=0.03). The favorable outcome (90-day mRS 0-2), intracerebral hemorrhage and procedural complications were similar in both groups. Conclusion Atherosclerotic occlusion of the EICA in acute tandem strokes was associated with a lower rate of mTICI 2b-3 reperfusion but similar functional and safety outcomes when compared with high-grade EICA stenosis

The bioenergetic role of dioxygen and the terminal oxidase(s) in cyanobacteria

AbstractOwing to the release of 13 largely or totally sequenced cyanobacterial genomes (see http://www.kazusa.or.jp/cyano and www.jgi.doe.gov/), it is now possible to critically assess and compare the most neglected aspect of cyanobacterial physiology, i.e., cyanobacterial respiration, also on the grounds of pure molecular biology (gene sequences). While there is little doubt that cyanobacteria (blue-green algae) do form the largest, most diversified and in both evolutionary and ecological respects most significant group of (micro)organisms on our earth, and that what renders our blue planet earth to what it is, viz. the O2-containing atmosphere, dates back to the oxygenic photosynthetic activity of primordial cyanobacteria about 3.2×109 years ago, there is still an amazing lack of knowledge on the second half of bioenergetic oxygen metabolism in cyanobacteria, on (aerobic) respiration. Thus, the purpose of this review is threefold: (1) to point out the unprecedented role of the cyanobacteria for maintaining the delicate steady state of our terrestrial biosphere and atmosphere through a major contribution to the poising of oxygenic photosynthesis against aerobic respiration (“the global biological oxygen cycle”); (2) to briefly highlight the membrane-bound electron-transport assemblies of respiration and photosynthesis in the unique two-membrane system of cyanobacteria (comprising cytoplasmic membrane and intracytoplasmic or thylakoid membranes, without obvious anastomoses between them); and (3) to critically compare the (deduced) amino acid sequences of the multitude of hypothetical terminal oxidases in the nine fully sequenced cyanobacterial species plus four additional species where at least the terminal oxidases were sequenced. These will then be compared with sequences of other proton-pumping haem–copper oxidases, with special emphasis on possible mechanisms of electron and proton transfer

Cell penetration, herbicidal activity, and in-vivo-toxicity of oligo-arginine derivatives and of novel guanidinium-rich compounds derived from the biopolymer cyanophycin Grogg, Marcel and Hilvert, Donald and Ebert, Marc-Olivier and Beck, Albert K. and Seebach, Dieter and Kurth, Felix and Dittrich, Petra S. and Sparr, C. and Wittlin, Sergio and Rottmann, Matthias and Mäser, Pascal

Oligo‐arginines are thoroughly studied cell‐penetrating peptides (CPPs, Figures 1 and 2). Previous in‐vitro investigations with the octaarginine salt of the phosphonate fosmidomycin (herbicide and anti‐malaria drug) have shown a 40‐fold parasitaemia inhibition with P. falciparum, compared to fosmidomycin alone (Figure 3). We have now tested this salt, as well as the corresponding phosphinate salt of the herbicide glufosinate, for herbicidal activity with whole plants by spray application, hoping for increased activities, i.e. decreased doses. However, both salts showed low herbicidal activity, indicating poor foliar uptake (Table 1). Another pronounced difference between in‐vitro and in‐vivo activity was demonstrated with various cell‐penetrating octaarginine salts of fosmidomycin: intravenous injection to mice caused exitus of the animals within minutes, even at doses as low as 1.4 μmol/kg (Table 2). The results show that use of CPPs for drug delivery, for instance to cancer cells and tissues, must be considered with due care. The biopolymer cyanophycin is a poly‐aspartic acid containing argininylated side chains (Figure 4); its building block is the dipeptide H‐βAsp‐αArg‐OH (H‐Adp‐OH). To test and compare the biological properties with those of octaarginines we synthesized Adp8‐derivatives (Figure 5). Intravenouse injection of H‐Adp8‐NH2 into the tail vein of mice with doses as high as 45 μmol/kg causes no symptoms whatsoever (Table 3), but H‐Adp8‐NH2 is not cell penetrating (HEK293 and MCF‐7 cells, Figure 6). On the other hand, the fluorescently labeled octamers FAM‐(Adp(OMe))8‐NH2 and FAM‐(Adp(NMe2))8‐NH2 with ester and amide groups in the side chains exhibit mediocre to high cell‐wall permeability (Figure 6), and are toxic (Table 3). Possible reasons for this behavior are discussed (Figure 7) and corresponding NMR spectra are presented (Figure 8)

Steindenkmäler der römischen Kaiserzeit in Germania Superior mit einem Hinweis auf ein Gewerbe

À partir des publications existantes, nous avons constitué une base de données des monuments lapidaires antiques de Germanie supérieure portant une indication relative à un métier. Une évaluation préliminaire des activités artisanales a montré une prédominance des métiers du travail du bois. Pour ceux-ci, la profession a été déterminée par comparaison des outils représentés avec des outils réels de l’époque romaine. Ensuite, le coût des monuments funéraires a été mis en parallèle avec l’estimation du coût de la vie et du salaire moyen des artisans: il apparaît qu’un simple artisan ne pouvait pas accéder à un tel bien. Par conséquent, les personnages représentés devaient appartenir à une classe sociale relativement aisée, probablement des maîtres-artisans, chefs ou responsables de grands ateliers.Based on existing publications, we constructed a database of the Antique lapidary monuments of the Upper Germania which bear an indication of a profession. A preliminary evaluation of the artisanal activities showed a predominance of wood working activities. The profession was determined through comparisons of the tools represented and actual tools from the Roman period. The cost of the funerary monuments was then correlated with an estimation of the cost of life and the average salary of the artisans: it appears that a simple craftsman could not have afforded such a monument. The individuals represented must therefore have belonged to a relatively affluent social class, and were probably master craftsmen, or directors or supervisors of large workshops.Für die Provinz Germania Superior wurden die vorhandenen und dokumentierten Steindenkmäler mit einem Bezug zu einem Gewerbe in einer Datenbank zusammengestellt. Eine erste Auswertung der handwerklichen Tätigkeiten zeigt, dass in Germania superior die Holzwirtschaft dominiert. An diesem Beispiel wurde dann eine Zuordnung der Werkzeuge zu den Tätigkeiten erarbeitet, wobei diese mit real existierenden Werkzeugen aus der Römerzeit verglichen wurden. Zur besseren gesellschaftlichen Einordnung der dargestellten Personen wurden die Lebenshaltungskosten und der durchschnittliche Verdienst von Handwerkern ermittelt und den zugänglichen Kosten von Steindenkmälern gegenübergestellt. Aus dieser Betrachtung folgt, dass sich einfache Handwerker keinen Grabstein leisten konnten. Bei den Dargestellten handelt es sich daher um Handwerksmeister mit einem größeren Betrieb

Optische Modellierung von Dünnschicht-Silizium-Solarzellen mit statistischen und periodischen Licht-Management-Strukturen

Die Entwicklung effizienter Licht-Management-Konzepte ist eine Voraussetzung für den weiteren Erfolg der Dünnschicht-Silizium-Photovoltaik. Diese Dissertation präsentiert optische Simulationen von Dünnschicht Silizium-Solarzellen mit statistischen und periodischen absorptionsverstärkenden Texturen. Für die Simulation von statistisch texturierten Solarzellen wird zunächst eine Synthetisierungsmethode für raue Oberflächen charakterisiert und als zur Generierung der Morphologie von kommerziell erhältlichen Fluor-dotierten Zinn-Oxid Oberflächen geeignet befunden. Die ausgedehnten rauen Grenzflächen in den Bauelementen werden durch Monte Carlo Sampling kleiner Rechengebiete simuliert. Modellfehler verbleiben durch die kleine Gebietsgröße und die Wahl der Randbedingungen an den seitlichen Oberflächen. Eine Analyse dieser Fehler ergibt, dass relativ kleine Rechengebiete zur Modellierung von ausgedehnten rauen Grenzflächen in Dünnschicht Silizium-Solarzellen ausreichend sind. Die simulierte Quanteneffizienz von Zellen mit 2D rauen Grenzflächen und 1D Schnitten von rauen Grenzflächen werden verglichen. Abschließend wird ein oft eingesetzter halb-empirischer statistischer ray tracing Algorithmus für ein Test-Schichtsystem mit der rigorosen Simulation verglichen. Für das Design von absorptionsverstärkenden Texturen für polykristalline Silizium-Zellen müssen die Wachstumseigenschaften der Kristalle stark berücksichtigt werden. Es werden Simulationen einer periodischen absorptionsverstärkenden Textur präsentiert, die in starker Verbindung mit der experimentellen Entwicklung durchgeführt wurden. Ein präzises geometrisches Modell wird auf der Basis von Querschnittsbildern einer experimentellen 3D-Struktur erstellt. Ein Vergleich von Absorptanz-Messungen mit der simulierten Absorptanz des Modells ergibt eine sehr gute quantitative Übereinstimmung. Das erstellte Modell wird in eine vollständige Solarzellstruktur eingebaut und durch Skalierung sowie Variation des Rückreflektors weiter untersucht. Erhöhte Absorptionsverstärkungsfaktoren, die allerdings wegen parasitärer Absorption in dem untersuchten realistischen System unterhalb des statistischen Grenzwerts der geometrischen Optik für uniforme Schichten liegen, treten bei bestimmten Texturperioden auf. Die Resultate der Skalierungsreihe unterstreichen die Bedeutung einer Silizium-Schichtdicke von zumindest mehreren Mikrometern zum Erreichen einer hohen Quanteneffizienz nahe der Bandkante. Eine deutliche Verbesserung der Quanteneffizienz wird für die untersuchte Struktur durch den Einsatz eines abgetrennten, flachen Rückreflektors erreicht. Die resultierenden simulierten Zellen besitzen in diesem Fall eine mit einem Einfachdurchgang durch mehr als 37 µm Silizium vergleichbare Absorptanz. Ein weiteres Anwendungsfeld der für Solarzellen entwickelten Herstellungsmethode für periodische Texturen sind planare photonische Kristalle. In einem ersten Test werden spekulare Reflektivitätsmessungen an den texturierten und mit Silizium beschichteten Substraten mit simulierten Bandstrukturen verglichen.Better light trapping concepts are a prerequisite for the success of silicon thin film photovoltaics. This thesis presents optical simulations of silicon thin film solar cells with statistical and periodic absorption enhancing textures. For simulation of statistically textured solar cells a rough surface synthesization method is characterized and found applicable for generation of the morphology of commercial fluorine doped tin oxide surfaces. The extended rough interface scatterer is modeled by a Monte Carlo sampling of small interface representations. Model errors are induced by the small lateral computational domain extent and the choice of lateral boundary conditions. A quantification of these errors yields that a sampling of relatively small domain widths is sufficient for modeling extended rough surfaces in silicon thin film devices. Cell efficiencies resulting from the simulation of 2D rough surfaces and 1D surface cuts are compared. Finally, a commonly employed statistical ray tracing algorithm is evaluated against rigorous simulation for a test case. For light trapping texture design of polycrystalline thin film devices, the crystal growth characteristics need to be strongly considered. Simulations of a periodic light trapping texture are done in close connection to experimental development. A precise geometrical model is first reconstructed from cross–sectional images of the experimental structure. A comparison of optical absorptance measurements with the simulated absorptance of the model yields a very good quantitative agreement. The obtained model is completed to a full solar cell and further analyzed by scaling and by back reflector variation. Elevated light path improvement factors, however still below the statistical limit due to the parasitic absorption included in the simulated model, are found for specific texture periods. The results from the scaling analysis highlight the importance of achieving a few micrometers layer thickness of the deposited silicon to be able to attain high quantum efficiencies in solar cells. A considerable enhancement is reached by employing a detached flat back reflector with the studied silicon structures. The resulting simulated cells have a single–pass comparable absorptance of more than 37 µm of silicon. A different field of research, for which the periodic patterning and polycrystalline silicon growth methods - developed for microstructuring solar cell absorbers - might be applicable, is planar photonic crystal structures. In a first test, the general quality of a patterned and silicon coated substrate is assessed by a comparison of specular reflectivity measurements to simulated band structures. Good agreement is found between experiment and simulation

Cost-effectiveness analysis of the research Project InSeL taking into account the established Secondary control power

In einem, zu einem Netzwerk zusammengeschlossenen Hamburger Liegenschaften abbildenden, Matlab/Simulink Modell soll der übergeordnete Regler so angepasst werden, dass die eingesetzte Sekundärregelleistung bei der Ausführung der Regelung berücksichtigt wird. Aufgabe des übergeordneten Reglers ist es den Summenlastverlauf entlang des prognostizierten Fahrplans zu regeln und möglichst genau einzuhalten, hierbei sind von den Liegenschaften vorgegebene Lastgrenzen sowie selbsttätiges Zu- und Abschalten von Verbrauchern innerhalb der Liegenschaften zu berücksichtigen. Durch die Berücksichtigung der Sekundärregelleistung soll ermittelt werden, ob die Kosten des Bilanzkreises, für den Einsatz von Ausgleichsenergie reduziert werden können.Inside this report the global controller in a Matlab/Simulink model of a network of properties of the City of Hamburg, is adjusted so that the used secondary control power is taken into account in carrying out the scheme. The task of the global control, is the regulation of a sum of load curves to a projected time table. The consideration of the secondary control power is used to find out whether the costs of the accounting grid can be reduced for the use of balancing energy

Optical modeling of thin film silicon solar cells with random and periodic light management textures

Better light trapping concepts are a prerequisite for the success of silicon thin film photovoltaics. This thesis presents optical simulations of silicon thin film solar cells with statistical and periodic absorption enhancing textures. For simulation of statistically textured solar cells a rough surface synthesization method is characterized and found applicable for generation of the morphology of commercial fluorine doped tin oxide surfaces. The extended rough interface scatterer is modeled by a Monte Carlo sampling of small interface representations. Model errors are induced by the small lateral computational domain extent and the choice of lateral boundary conditions. A quantification of these errors yields that a sampling of relatively small domain widths is sufficient for modeling extended rough surfaces in silicon thin film devices. Cell efficiencies resulting from the simulation of 2D rough surfaces and 1D surface cuts are compared. Finally, a commonly employed statistical ray tracing algorithm is evaluated against rigorous simulation for a test case. For light trapping texture design of polycrystalline thin film devices, the crystal growth characteristics need to be strongly considered. Simulations of a periodic light trapping texture are done in close connection to experimental development. A precise geometrical model is first reconstructed from cross sectional images of the experimental structure. A comparison of optical absorptance measurements with the simulated absorptance of the model yields a very good quantitative agreement. The obtained model is completed to a full solar cell and further analyzed by scaling and by back reflector variation. Elevated light path improvement factors, however still below the statistical limit due to the parasitic absorption included in the simulated model, are found for specific texture periods. The results from the scaling analysis highlight the importance of achieving a few micrometers layer thickness of the deposited silicon to be able to attain high quantum efficiencies in solar cells. A considerable enhancement is reached by employing a detached flat back reflector with the studied silicon structures. The resulting simulated cells have a single pass comparable absorptance of more than 37 m of silicon. A different field of research, for which the periodic patterning and polycrystalline silicon growth methods developed for microstructuring solar cell absorbers might be applicable, is planar photonic crystal structures. In a first test, the general quality of a patterned and silicon coated substrate is assessed by a comparison of specular reflectivity measurements to simulated band structures. Good agreement is found between experiment and simulatio