The ionospheric response to solar extreme ultraviolet (EUV) variability during 2011–2014 is shown by simple proxies based on Solar Dynamics Observatory/Extreme Ultraviolet Variability Experiment solar EUV spectra. The daily proxies are compared with global mean total electron content (TEC) computed from global TEC maps derived from Global Navigation Satellite System dual frequency measurements. They describe about 74% of the intra-seasonal TEC variability. At time scales of the solar rotation up to about 40 days there is a time lag between EUV and TEC variability of about one day, with a tendency to increase for longer time scales.

So far, glioblastomas cannot be cured by standard therapy and have an extremely poor median survival of about 15 months. The photodynamic therapy (PDT) with next generation photosensitizers, reaching a higher therapeutic depth, might offer a new, adjuvant treatment strategy in brain cancer therapy. Here, we investigated the effect of THPTS-PDT combined with ionizing irradiation (IR) on glioblastoma cells in vitro and in vivo. Results: THPTS colocalized to mitochondria and was not found in the nucleus. THPTS (2–20 μg/ml)-PDT significantly reduced the proliferation, metabolic activity and clonogenic survival and induced cell death mainly through apoptosis and autophagy. THPTS-PDT combined with IR decreased the clonogenicity significantly compared to single treatments. THPTS (≤ 300 μg/ml) alone showed no dark toxicity. The maximum therapeutic depth of THPTS-PDT in C6 glioblastomas was 13 mm. Materials and Methods: Three human glioblastoma cell lines (U-87 MG, A-172, DBTRG-05MG) were incubated with THPTS (1–300 μg/ml) 3–24 hours before laser treatment (760 nm, 30 J/cm²). THPTS localization and effects on metabolic activity, proliferation, cell death mechanisms and long-term reproductive survival were assessed. IR was conducted on an X-ray unit (0.813 Gy/min). Results were verified in vivo on a subcutaneous C6 glioblastoma model in Wistar rats. Conclusions: This study demonstrated efficient THPTS-PDT in glioblastoma cells, in vitro and in vivo. The combinatorial effects of THPTS-PDT and IR are of specific clinical interest as enhanced eradication of infiltrating glioblastoma cells in the tumor surrounding tissue might possibly reduce the commonly occurring local relapses.

Synchrocyclotrons and laser based particle accelerators, developed with the goal to enable more compact particle therapy facilities, may bring highly pulsed radiation field to external beam radiation therapy. In addition, such highly pulsed fields may be desirable due to their potential clinical benefits regarding better healthy tissue sparing or improved gating for moving tumors. However, they pose new challenges for dosimetry, the corner stone of any application of ionizing radiation. These challenges affect both clinical and radiation protection dosimetry. Air-filled ionization chambers, which dominate clinical dosimetry, face the problem of increased signal loss due to volume recombination when a highly pulsed field liberates a large amount of charge in a short time in the chamber. While well established descriptions exist for this volume recombination for the moderately pulsed fields in current use (Boag's formulas), the assumptions on which those descriptions are based will most likely not hold in the prospective, highly pulsed fields of future accelerators. Furthermore, ambient dose rate meters used in radiation protection dosimetry as survey meters or fixed installations are generally only tested for continuous fields, casting doubt on their suitability to measure pulsed fields. This thesis investigated both these aspects of dosimetry - clinical as well as radiation protection - to enable the medical application of highly pulsed radiation fields. For a comprehensive understanding, experimental investigations were coupled with theoretical considerations and developments. Pulsed fields, varying in both dose-per-pulse and pulse duration over a wide range, were generated with the ELBE research accelerator, providing a 20 MeV pulsed electron beam. Ionization chambers for clinical dosimetry were investigated using this electron beam directly, with an aluminium Faraday cup providing the reference measurement. Whereas the dose rate meters were irradiated in the photon field generated from stopping the electron beam in the Faraday cup. In those measurements, the reference was calculated from the ionization chamber, then serving a an electron beam monitor, cross-calibrated to the photon field with thermoluminescent dosimeters. Three dose rate meters based on different operating principles were investigated, covering a large portion of the operating principles used in radiation protection: the ionization chamber based RamION, the proportional counter LB 1236-H10 and the scintillation detector AD-b. Regarding clinical dosimetry, measurements of two prominent ionization chamber geometries, plane-parallel (Advanced Markus chamber) and thimble type (PinPoint chamber), were performed. In addition to common air-filled chambers, chambers filled with pure nitrogen and two non-polar liquids, tetramethylsilane and isooctane, were investigated. In conjunction with the experiments, a numerical solution of the charge liberation, transport, and recombination processes in the ionization chamber was developed to calculate the volume recombination independent of the assumptions necessary to derive Boag's formulas. Most importantly, the influence of the liberated charges in the ionization chamber on the electric field, which is neglected in Boag's formulas, is included in the developed calculation. Out of the three investigated dose rate meters only the RamION could be identified as an instrument truly capable of measuring a pulsed field. The AD-b performed below expectations (principally, a scintillator is not limited in detecting pulsed radiation), which was attributed to the signal processing, emphasizing the problem of a typical black-box signal processing in commercial instruments. The LB 1236-H10, on the other hand, performed as expected of a counting detector. While this supports the recent effort to formalize these expectations and standardize testing for counting dosimeters in DIN IEC/TS 62743, it also highlights the insufficiency of counting detectors for highly pulsed fields in general and shows the need for additional normative work to establish requirements for dose rate meters not based on a counting signal (such as the RamION), for which no framework currently exists. With these results recognized by the German radiation protection commission (SSK) the first steps towards such a framework are taken. The investigation of the ionization chambers used in radiation therapy showed severe discrepancies between Boag's formulas and the experimentally observed volume recombination. Boag's formulas describe volume recombination truly correctly only in the two liquid-filled chambers. All the gas-filled chambers required the use of effective parameters, resulting in values for those parameters with little to no relation to their original meaning. Even this approach, however, failed in the case of the Advanced Markus chamber for collection voltages ≥ 300 V and beyond a dose-per-pulse of about 100 mGy. The developed numerical model enabled a much better calculation of volume recombination and allowed the identification of the root of the differences to Boag's formulas as the influence of the liberated charges on the electric field. Increased positive space charge due to increased dose-per-pulse slows the collection and reduces the fraction of fast, free electrons, which are unaffected by volume recombination. The resultant increase in the fraction of charge undergoing volume recombination, in addition to the increase in the total amount of charge, results in an increase in volume recombination with dose-per-pulse that is impossible to describe with Boag's formulas. It is particularly relevant in the case of high electric fields and small electrode distances, where the free electron fraction is large. In addition, the numerical calculation allows for arbitrary pulse durations, while Boag's formulas apply only to very short pulses. In general, the numerical calculation worked well for plane-parallel chambers, including those filled with the very diverse media of liquids, nitrogen and air. Despite its increased complexity, the thimble geometry could be implemented as well, although, in the case of the PinPoint chamber, some discrepancies to the experimental data remained, probably due to the required geometrical approximations. A possible future development of the numerical calculation would be an improved description of the voltage dependence of the volume recombination. At the moment it requires characterizing a chamber at each desired collection voltage, which could be eliminated by an improved modeling of the volume recombination's dependence on collection voltage. Nevertheless, the developed numerical calculation presents a marked improvement over Boag's formulas to describe the dose-per-pulse dependence and pulse duration dependence of volume recombination in ionization chambers, in principle enabling the application of ionization chambers in the absolute dosimetry of highly pulsed fields.

In Durchlauföfen zur Erwärmung von Gütern werden die Materialien zu einem großen Teil entweder auf Schienen und Hubbalken oder mittels Transportrollen durch die Öfen transportiert. Die Transportrollen sind auf den ersten Blick ein Widerstand bezüglich des Wärmeübergangs aus dem Ofenraum unterhalb der Rollen an die Unterseite der Güter. Eine Vergleichsmessung zeigte allerdings, dass die Stoffe auf den Transportrollen durch die zusätzliche Wärmeabgabe der Transportrollen an die Unterseite der Werkstoffe schneller erwärmt werden als auf Schienen. Im Rahmen dieser Arbeit wurde ein mathematisches Modell entwickelt, das die Guterwärmung in einem Rollenofen abbildet. Nach der experimentellen Verifizierung des mathematischen Modells wurden die Transportrollenparameter ermittelt, die die Guterwärmung in einem Rollenofen beschleunigen. Je geringer Rollendurchmesser und Rollenteilung sind und je höher die Gutgeschwindigkeit ist, umso mehr verbessern Rollen die Guterwärmung.

The simplified approach of a turbid medium is commonly applied in theory of radiative transfer for vegetation media. Oriented planar model leaves are assumed whose normals are always confined to the upper half space. These orientations are described with the help of so-called leaf normal distribution functions (LNDFs) so that, within the scope of the turbid theory, a radiative transfer equation can be derived in which the so called Ross-Nilson function G occurs explicitly. This function, as introduced by J. Ross, is based on geometrical considerations and is therefore called geometry function, or shortly G-function (GF). To solve the latter equation G must be known. GF is calculated from the LNDF and was originally derived in an explicit and analytical form for strongly simplified LNDFs only. We demonstrated in a previous work that GF can be calculated also for other standard LNDFs. Based on the latter LNDFs we introduce here a generalised trigonometric LNDF and present the respective formula for G. / Die vereinfachte Annahme eines turbiden Mediums findet in der Theorie des Strahlungstransfers für Vegetationsmedien breite Anwendung. Darin werden orientierte ebene Modellblätter angenommen, deren Normalen stets in den oberen Halbraum weisen. Diese Orientierungen werden mittels sogenannter Blattnormalenverteilungen (BNV) beschrieben, so dass sich im Rahmen der turbiden Theorie eine Strahlungstransfergleichung ableiten lässt, in der die sogenannte Ross-Nilson-Funktion G explizit auftritt. Diese von J. Ross eingeführte Funktion basiert auf geometrischen Betrachtungen und wird daher auch Geometriefunktion genannt oder kurz G-Funktion. G muss zur Lösung der vorigen Gleichung bekannt sein. Es leitet sich aus der BNV ab und konnte in expliziter sowie analytischer Form bislang lediglich für stark vereinfachte BNV hergeleitet werden. Wie wir an dieser Stelle in einem früheren Beitrag gezeigt haben, lässt sich G darüber hinaus für andere standardisierte BNV berechnen. Auf letzteren aufbauend führen wir jetzt eine verallgemeinerte trigonometrische BNV ein und präsentieren die entsprechende Formel für G.

Non-spherical particles scatter and polarize solar radiation depending on their shape, size, chemical composition and orientation. In addition, such information is crucial in radiative transfer modeling. Therefore, in this study, the implementation of polarization into a three-dimensional radiative transfer model is introduced and its validation through benchmark results. The model is based on the statistical Monte Carlo method (in the forward scheme) and takes into account multiple scattering and the polarization states of the monochromatic radiation. It calculates column-response pixel-based polarized radiative densities for 3D inhomogeneous cloudy atmospheres and is hence best suited for use in remote sensing applications. To this end, the model can be used to explore the potential of remote sensing techniques which distinguish between spherical and non-spherical particles on the one side and coarse mode dust particles and ice particles on the other side.

The ionospheric response to solar EUV variability during 2011 - 2014 is shown by an EUV proxy based on primary ionization calculations using combined solar spectra from SDO/EVE and SolACES on board the ISS. The daily proxies are compared with global mean TEC analyses. At time scales of the solar rotation and longer, there is a time lag between EUV and TEC variability of about one to two days, indicating dynamical processes in the thermosphere/ionosphere systems. This lag is not seen at shorter time scales. When taking this delay into account the TEC variance at the seasonal and short-term time scale explained by EUV variations increases from 71% to 76%. / Die ionosphärische Antwort auf Variationen des solaren EUV im Zeitraum 2011-2014 wird anhand eines Proxys dargestellt, welcher die primäre Ionisation auf der Basis gemessener solare EUV-Spektren beinhaltet. Die täglichen Werte werden mit Analysen des global gemittelten Gesamtelektronengehalts verglichen. Auf Zeitskalen der solaren Rotation und länger findet sich eine Zeitverzögerung zwischen der EUV-Variation und des derjenigen des Gesamtelektronengehalts von ein bis 2 Tagen, welche auf dynamische Prozesse im System Thermosphäre/Ionosphäre hinweist. Die Verzögerung ist auf kurzen Zeitskalen nicht zu sehen. Wenn diese Verzögerung berücksichtigt wird, erhöht sich die durch EUV-Variationen erklärte Varianz des Elektronengehalts von 71% auf 76%.

Based on airborne spectral imaging observations, three-dimensional (3-D) radiative effects between Arctic boundary layer clouds and highly variable Arctic surfaces have been identified and quantified. A method is presented to discriminate sea ice and open water in cloudy conditions based on airborne upward radiance measurements in the visible spectral range. This separation simultaneously reveals that the transition of radiance between open water and sea ice is not instantaneous in cloudy conditions but horizontally smoothed. In general, clouds reduce the nadir radiance above bright surfaces in the vicinity of open water, while the nadir radiance above open sea is enhanced compared to situations with clouds located above sea ice surfaces. With the help of the observations and 3-D radiative transfer simulations, this effect was quantified. This affected distance deltaL was found to depend on both cloud and sea ice properties. For a low level cloud at 0-200 m altitude, as observed during the Arctic field campaign Vertical Distribution of Ice in Arctic Clouds (VERDI) in 2012, an increase of the cloud optical thickness from tau = 1 to tau = 10 leads to a decrease of deltaL from 600 to 250 m. An increase in cloud base altitude or cloud geometrical thickness results in an increase of deltaL. Furthermore, the impact of these 3-D-radiative effects on a retrieval of cloud optical properties was investigated. The enhanced brightness of a dark pixel next to an ice edge results in uncertainties of up to 90 % in retrievals of tau and up to 30 % in retrievals of the effective radius reff. With the help of detlaL quantified here, an estimate of the distance to the ice edge is given where the retrieval uncertainties due to 3D-effects are negligible. / Mit Hilfe flugzeuggetragener abbildender spektraler Beobachtungen wurden 3-D Strahlungseffekte zwischen arktischen Grenzschichtwolken sowie der hochvariablen arktischen Bodenoberfläche identifiziert und quantifiziert. Eine Methode zur Differenzierung von Meereis und offener Wasserflächen, auf Grundlage flugzeuggetragener Messungen der aufwärtsgerichteten Strahldichte im sichtbaren Spektralbereich, während bewölkter Bedingungen wird vorgestellt. Diese Differenzierung zeigt gleichzeitig auf, dass die Strahldichtereduzierung beim Übergang vom Meereis zu den offenen Wasserflächen nicht unmittelbar erfolgt, sondern horizontal geglättet ist. Allgemein verringern Wolken in der Umgebung von Eiskanten die Nadir-Strahldichte über den hellen Eisflächen und erhöhen sie über dunklen Meeresoberflächen. Mit Hilfe von 3-D Strahlungstransferrechnungen wurde dieser Effekt quantifiziert. Die Reichweite dieses Effektes wird sowohl von den Wolken- als auch den Oberflächeneigenschaften beeinflusst. Für eine flache Wolke zwischen 0 und 200 m, so wie sie während der arktischen Feldkampagne Vertical Distribution of Ice in Arctic Clouds (VERDI), 2012 beobachtet werden konnte, führt eine Erhöhung der wolkenoptischen Dicke von tau = 1 zu tau = 10 zu einer Verringerung in deltaL von 600 zu 250 m. Zudem führt eine Erhöhung der Wolkenhöhe und ihrer geometrischen Dicke zu einer Zunahme von deltaL. Anschließend wurde der Einfluss dieser 3-D Strahlungseffekte auf die Ableitungsergebnisse von tau untersucht. Die Aufhellung eines dunkleren Pixels neben der Eiskante führt zu Unsicherheiten von bis zu 90 % bei der Ableitung von . Beim effektiven Radius zu bis zu 30 %. DeltaL ist ein Maß mit Hilfe dessen die Entfernung zur Eiskante bestimmt werden kann, ab welcher die Unsicherheiten bezüglich der 3-D Effekte vernachlässigt werden können.

In this paper spectral solar zenith radiances are analyzed which were obtained from ship–based measurements over the Atlantic ocean. In combination with high–resolution lidar and microwave remote sensing optical and microphysical cloud properties were retrieved using spectral radiation data. To overcome problems of existing transmissivity–based cloud retrievals, a new retrieval algorithm is introduced which circumvents retrieval ambiguities and reduces the influence of measurement uncertainties. The method matches radiation measurements of ratios of spectral transmissivity at six wavelengths with modeled transmissivities. The new retrieval method is fast and accurate, and thus suitable for operational purposes. It is applied to homogeneous and inhomogeneous liquid water and cirrus clouds. The results from the new algorithm are compared to observations of liquid water path obtained from a microwave radiometer, yielding an overestimation for thick liquid water clouds but a slight underestimation for thin clouds. / In dem vorliegenden Artikel werden abwärtsgerichtete spektrale Strahldichten analysiert, die mithilfe schiffsgebundener Beobachtungen über dem Atlantischen Ozean gemessen wurden. In Verbindung mit hochauflösenden Lidar und Mikrowellenradiometer Fernerkundungsverfahren werden optische und mikrophysikalische Wolkeneigenschaften aus spektralen Daten abgeleitet. Um Probleme bereits existierender Verfahren, die auf Transmissionen basieren, zu beseitigen, wird ein neuer Fernerkundungsalgorithmus vorgestellt, der nicht nur Zweideutigkeiten in der Bestimmung der Parameter umgeht, sondern auch den Einfluss von Messunsicherheiten verringert. Die Methode vergleicht gemessene spektrale Transmissionsverhältnisse bei sechs Wellenlängen mit modellierten Verhältnissen. Die neue Fernerkundungsmethode ist schnell und exakt, sodass sie für operative Zwecke geeignet ist. Sie wird für homogene und inhomogene Wasserwolken als auch für Cirren angewendet. Die Ergebnisse des neuen Ableitungsverfahrens werden mit Beobachtungen des Flüssigwasserpfades eines Mikrowellenradiometers verglichen. Daraus ergibt sich eine Überschätzung des Flüssigwasserpfades unter dicken Wolken, jedoch eine leichte Unterschätzung für dünne Wolken.

Das vorliegende Unterrichtsmaterial bietet Ihnen und Ihren Schülern Einblicke in das faszinierende Forschungsfeld der Astroteilchenphysik. Dabei steht die experimentelle Untersuchung von kosmischen Teilchen am Beispiel der Myonen im Vordergrund. In den KAPITELN 1 und 2 werden zunächst einige Hintergrundinformationen für Lehrkräfte, wie beispielsweise Anknüpfungspunkte an den Lehrplan, benötigte Vorkenntnisse der Schüler, Lernziele sowie fachliche und methodische Hinweise gegeben. KAPITEL 3 beschäftigt sich dann mit der kosmischen Strahlung an sich. Mit Hilfe der Betrachtung von Teilchen in einer Nebelkammer gelingt der Einstieg in das Thema der Astroteilchenphysik. Neben den Spuren bereits bekannter Teilchen wie z. B. Elektronen und Alpha-Teilchen begegnen den Schülern hier erstmalig auch Myonen. Mittels anderer Experimente werden diese dann genauer untersucht. Die Experimente und Fachtexte werden durch entsprechende Aufgaben ergänzt. Abschließend wird dann die Entstehung der Myonen thematisiert. In KAPITEL 4 finden sich die vollständigen Lösungen zu allen Aufgaben. KAPITEL 5 bietet einen Überblick über weiterführende Materialien zum Thema kosmische Strahlung.