Spinodal phase separation in semi-interpenetrating polymer networks - polystyrene-cross-polymethacrylate

Morphology control in semi-interpenetrating polymer networks has been achieved by means of a two-step process, separating morphology formation and polymerization/crosslinking. Phase textures formed during spinodal liquid/liquid demixing of a solution of atactic polystyrene in methacrylate monomers were arrested by thermoreversible gelation of the polymer-rich phase as this phase passed its glass transition temperature. The phase separated structure was permanently stabilized by low-temperature crosslinking ultraviolet (UV) polymerization of the methacrylate monomer, and studied by transmission electron microscopy. Thus, it was directly observed how the initial demixing process depended on the initial viscosity of the polymer solution and the mode of quenching. Arrest of the earliest stage of spinodal demixing resulted in separated domains of 0.05-0.08 m thickness, which were separated by a distance of the spinodal wavelength . A cocontinuous network only developed in a relatively late stage of demixing

Charakterisierung von optischen Komponenten eines Laserverstärkers mittels Spektralinterferometrie

One of the largest branches of modern optics is laser technology, which offers a wide range of applications in industry, medicine and research. In particular, the generation of subpicosecond laser pulses has greatly expanded the possibilities for the application of laser systems. An important milestone in the development of pulsed laser systems was the chirped pulse amplification (CPA) principle developed by Strickland and Mourou in 1985 [1], which earned them the Nobel Prize in 2018. The high peak powers that can be achieved by lasers employing the CPA schemes are used e.g. for experiments aiming at laser-driven proton acceleration. Such experiments are performed at the high intensity laser system POLARIS (Petawatt Optical Laser Amplifier for Radiation Intensive Experiments) which is operated at the Helmholtz Institute Jena. In order to characterize the plasma conditions during such experiments very precisely, an independent pump-probe setup is currently being developed. With this setup the precise characterization of the formation and temporal evolution of the plasma target becomes possible. For the plasma characterization setup, a CPA system consisting of a pulse stretcher, regenerative amplifier and pulse compressor is being developed. In order to characterize the pre-plasma, knowledge of the temporal shape of the laser pulse is important. One of the main big issues is the measurement of ultra short laser pulses with durations of 50 fs, which is shorter than the response time of any electronic detector. In order to measure such kind of laser pulses, a reference pulse with a comparable duration can be used to sample the pulse to be measured by a suitable detector. Such a sample pulse can be the pulse itself or another well characterized femtosecond laser pulse [2]. It is important to measure both amplitude and phase of the spectrum, although it is usually not possible to measure the latter directly. One of the most effective methods of laser pulse characterization is called spectral interferometry (SI) which was pioneered by Froehly et al. in 1973 [3]. It offers the p ossibility to measure the spectral phase and has attracted the attention of researchers because of its large sensitivity and high spectral resolution.SI has many applications in spectroscopy [4], plasma probing [5], characterization of dispersion, studies of nonlinear processes [6], materials and characterization of crystals [7]. SI is also the basis for new techniques of spectral phase measurement, such as frequency resolved optical gating (FROG) [2] or spectral phase interferometry for direct electric field construction (SPIDER) [8]. In section 2 of this Bachelor thesis, the fundamentals of ultrafast optics based on Maxwell’s equations are presented, Gaussian beams, optical pulses and their propagation in dispersive media are introduced. The method of spectral interferometry (SI) is fundamentally introduced and explained in section 3, different possibilities for characterizing the spectral phase are presented. The experimental setup for the characterization and a referencing measurement to well characterized materials is done in section 4. It is also investigated in section 4 which experimental issues can occur, how large their influences on the measurement are and how they can be resolved. The derived methods of spectral phase characterization are used in section 5 to specify the optical components of an amplifier in a CPA laser system. The components of the laser amplifier are categorized and their effects on the spectral phase are compared and discussed. It is then summarized why dispersion measurements are important and how the method of SI can be utilized to select suitable components for a laser amplifier

On-line monitoring using Multi-Process Kalman Filtering

On-line monitoring of time series becomes more and more important in different areas of application like medicine, biometry and finance. In medicine, on-line monitoring of patients after transplantation of renals (Smith83) is an easy and prominent example. In finance, fast end reliable recognition of changes in level and trend of intra-daily stock market prices is of obvious interest for ordering and purchasing. In this project, we currently consider monitoring of surgical data like heart-rate, blood pressure and oxygenation. From a statistical point of view, on-line monitoring can be considered as on-line detection of changepoints in time series. That means, changepoints have to be detected in real time as new observations come in, usually in short time intervals. Retrospective detection of changepoints, after the whole batch of observations has been recorded, is nice but useless in monitoring patients during an operation. There are various statistical approaches conceivable for on-line detection of changepoints in time series. Dynamic or state space models seem particularly well suited because ``filtering'' has historically been developed exactly for on-line estimation of the ``state'' of some system. Our approach is based on a recent extension of the so-called multi-process Kalman filter for changepoint detection (Schnatter94). It turned out, however, that some important issues for adequate and reliable application have to be considered, in particular the (appropriate) handling of outliers and, as a central point, adaptive on-line estimation of control- or hyper-parameters. In this paper, we describe a filter model that has this features and can be implemented in such a way that it is useful for real time applications with high frequency time series data. Recently, simulation based methods for estimation of non-Gaussian dynamic models have been proposed that may also be adapted and generalized for the purpose of changepoint detection. Most of them solve the smoothing problem, but very recently some proposals have been made that could be useful also for filtering and, thus, for on-line monitoring (Kitagawa96a,Kitagawa96b,Shephard96). If these approaches are a useful alternative to our development needs a careful comparison in future and is beyond the scope of this paper

How to improve drug dosing for patients with renal impairment in primary care - a cluster-randomized controlled trial

Background: Patients with chronic kidney disease (CKD) are at increased risk for inappropriate or potentially harmful prescribing. The aim of this study was to examine whether a multifaceted intervention including the use of a software programme for the estimation of creatinine clearance and recommendation of individual dosage requirements may improve correct dosage adjustment of relevant medications for patients with CKD in primary care. Methods: A cluster-randomized controlled trial was conducted between January and December 2007 in small primary care practices in Germany. Practices were randomly allocated to intervention or control groups. In each practice, we included patients with known CKD and elderly patients (>=70 years) suffering from hypertension. The practices in the intervention group received interactive training and were provided a software programme to assist with individual dose adjustment. The control group performed usual care. Data were collected at baseline and at 6 months. The outcome measures, analyzed across individual patients, included prescriptions exceeding recommended maximum daily doses, with the primary outcome being prescriptions exceeding recommended standard daily doses by 30% or more. Results: Data from 44 general practitioners and 404 patients are included. The intervention was effective in reducing prescriptions exceeding the maximum daily dose per patients, with a trend in reducing prescriptions exceeding the standard daily dose by more than 30%. Conclusions: A multifaceted intervention including the use of a software program effectively reduced inappropriately high doses of renally excreted medications in patients with CKD in the setting of small primary care practices

Bildung braucht Räume: Essensräume in Kitas und Schulen gestalten.

Essensräume können für Kitas und Schulen eine zweifache Bedeutung haben. Als Lebensräume können sie die Grundlage dafür bilden, dass sich Essen nicht auf die bloße Verpflegung von Kindern und Jugendlichen reduziert. Als Bildungsräume können sie synergetische Voraussetzungen für eine nachhaltige Ernährungs- und Verbraucherbildung in Kitas und Schulen schaffen. Die vorliegende Publikation erläutert Notwendigkeiten und skizziert Perspektiven einer pädagogischen Gestaltung von Essensräumen in Kitas und Schulen

Performance of irradiated thin n-in-p planar pixel sensors for the ATLAS Inner Tracker upgrade

The ATLAS collaboration will replace its tracking detector with new all silicon pixel and strip systems. This will allow to cope with the higher radiation and occupancy levels expected after the 5-fold increase in the luminosity of the LHC accelerator complex (HL-LHC). In the new tracking detector (ITk) pixel modules with increased granularity will implement to maintain the occupancy with a higher track density. In addition, both sensors and read-out chips composing the hybrid modules will be produced employing more radiation hard technologies with respect to the present pixel detector. Due to their outstanding performance in terms of radiation hardness, thin n-in-p sensors are promising candidates to instrument a section of the new pixel system. Recently produced and developed sensors of new designs will be presented. To test the sensors before interconnection to chips, a punch-through biasing structure has been implemented. Its design has been optimized to decrease the possible tracking efficiency losses observed. After irradiation, they were caused by the punch-through biasing structure. A sensor compatible with the ATLAS FE-I4 chip with a pixel size of 50x250 $\mathrm{\mu}$m$^{2}$, subdivided into smaller pixel implants of 30x30 $\mathrm{\mu}$m$^{2}$ size was designed to investigate the performance of the 50x50 $\mathrm{\mu}$m$^{2}$ pixel cells foreseen for the HL-LHC. Results on sensor performance of 50x250 and 50x50 $\mathrm{\mu}$m$^{2}$ pixel cells in terms of efficiency, charge collection and electric field properties are obtained with beam tests and the Transient Current Technique

Jeder Fehler zählt : das Frankfurter Fehlerberichts- und Lernsystem für Hausarztpraxen

Anderer Fehler sind gute Lehrer « – so lautet ein nur wenig bekanntes altes deutsches Sprichwort. Für medizinische Fehler galt das die längste Zeit nicht: entweder totgeschwiegen oder als »Kunstfehler « in das Licht der Öffentlichkeit gezerrt, entzogen sich ärztliche Fehler einer systematischen Analyse. Damit hat die Medizin lange eine wichtige Chance vertan. Am Institut für Allgemeinmedizin der Universität Frankfurt beschäftigt sich seit einigen Jahren ein Team unter Leitung von Prof. Dr. Ferdinand Gerlach intensiv mit der Fehlerforschung. ..