Kinetische Gleichungen für Systeme mit unendlich vielen Freiheitsgraden

In der Theorie stochastischer Prozesse und in der statistischen Mechanik versteht man unter kinetischen Gleichungen Differentialgleichungen für zeitabhängige Wahrscheinlichkeitsdichten, die in der Regel auf das Lebesgue-Maß bezogen sind. Dies ist für unendlich-dimensionale Räume nicht möglich, da sich für sie kein dem Lebesgue-Maß entsprechendes Maß definieren läßt. Keine besonderen Schwierigkeiten macht in unendlich-dimensionalen Räumen die Definition von Wahrscheinlichkeitsmaßen. Deshalb ist es praktisch, für Systeme mit unendlich vielen Freiheitsgraden Wahrscheinlichkeitsdichten gegen ein Wahrscheinlichkeitsmaß zu beziehen, das möglichst viele nützliche Eigenschaften des Lebesgue-Maßes hat. Die herausragende Eigenschaft des Lebesgue-Maßes ist seine Beziehung zur üblichen Differentiation, die gekoppelt ist mit anderen Eigenschaften. Wir werden hier eine Reihe der wichtigsten Beziehungen aufführen, um darlegen zu können, welche Eigenschaften für Systeme mit unendlich vielen Freiheitsgraden durch Modifikation beibehalten werden können, welche nicht. Die sich durch die Veränderung des Bezugsmaßes ergebenden Konsequenzen für kinetische Gleichungen werden am Schluß behandelt

Alpha-particle emitting 213Bi-anti-EGFR immunoconjugates eradicate tumor cells independent of oxygenation

Hypoxia is a central problem in tumor treatment because hypoxic cells are less sensitive to chemo- and radiotherapy than normoxic cells. Radioresistance of hypoxic tumor cells is due to reduced sensitivity towards low Linear Energy Transfer (LET) radiation. High LET α-emitters are thought to eradicate tumor cells independent of cellular oxygenation. Therefore, the aim of this study was to demonstrate that the cell-bound α-particle emitting 213Bi immunoconjugates efficiently kill hypoxic just like normoxic CAL33 tumor cells. For that purpose CAL33 cells were incubated with 213Bianti- EGFR-MAb or irradiated with photons with a nominal energy of 6 MeV both under hypoxic and normoxic conditions. Oxygenation of cells was checked via the hypoxia-associated marker HIF-1α. Survival of cells was analysed using the clonogenic assay. Cell viability was monitored with the WST colorimetric assay. Results were evaluated statistically using a t-test and a Generalized Linear Mixed Model (GLMM). Survival and viability of CAL33 cells decreased both after incubation with increasing 213Bi-anti-EGFR-MAb activity concentrations (9.25 kBq/ml – 1.48 MBq/ml) and irradiation with increasing doses of photons (0.5 – 12 Gy). Following photon irradiation survival and viability of normoxic cells were significantly lower than those of hypoxic cells at all doses analysed. In contrast, cell death induced by 213Bianti- EGFR-MAb turned out to be independent of cellular oxygenation. These results demonstrate for the first time that α-particle emitting 213Bi-immunoconjugates eradicate hypoxic tumor cells as effective as normoxic cells. Therefore, 213Biradioimmunotherapy seems to be an appropriate strategy for treatment of hypoxic tumors.JRC.E.5-Nuclear chemistr

How Relevant Is the Parallax Effect on Low Centered Pelvic Radiographs in Total Hip Arthroplasty

The correct cup position in total hip arthroplasty (THA) is usually assessed on anteroposterior low centered pelvic radiographs, harboring the risk of misinterpretation due to projection of a three-dimensional geometry on a two-dimensional plane. In the current study, we evaluate the effect of this parallax effect on the cup inclination and anteversion in THA. In the course of a prospective clinical trial, 116 standardized low centered pelvic radiographs, as routinely obtained after THA, were evaluated regarding the impact of central beam deviation on the cup inclination and anteversion angles. Measurements of the horizontal and vertical beam offset with two different methods of parallax correction were compared with each other. Furthermore, the effect of parallax correction on the accuracy ofmeasuring the cup position was investigated. The mean difference between the two parallax correction methods was 0.2° ± 0.1° (from 0° to 0.4°) for the cup inclination and 0.1° ± 0.1° (from −0.1° to 0.2°) for the anteversion. For a typically intended cup position of a 45° inclination and 15° anteversion, the parallax effect led to a mean error of −1.5° ± 0.3° for the inclination and 0.6° ± 1.0° for the anteversion. Central beam deviation resulted in a projected higher cup inclination up to 3.7°, and this effect was more prominent in cups with higher anteversion. In contrast, the projected inclination decreased due to the parallax effect up to 3.2°, especially in cups with high inclination. The parallax effect on routinely obtained low centered pelvic radiographs is low and not clinically relevant due to the compensating effect of simultaneous medial and caudal central beam deviation

Connective tissue growth factor in tumor pathogenesis

Key roles for connective tissue growth factor (CTGF/CCN2) are demonstrated in the wound repair process where it promotes myofibroblast differentiation and angiogenesis. Similar mechanisms are active in tumor-reactive stroma where CTGF is expressed. Other potential roles include prevention of hypoxia-induced apoptosis and promoting epithelial-mesenchymal transistion (EMT). CTGF expression in tumors has been associated to both tumor suppression and progression. For example, CTGF expression in acute lymphoblastic leukemia, breast, pancreas and gastric cancer correlates to worse prognosis whereas the opposite is true for colorectal, lung and ovarian cancer. This discrepancy is not yet understood

Analysis of Osteosarcoma Cell Lines and Patient Tissue Using a 3D In Vivo Tumor Model—Possible Effects of Punicalagin

Osteosarcomas are the most common primary malignant bone tumors and mostly affect children, adolescents, and young adults. Despite current treatment options such as surgery and polychemotherapy, the survival of patients with metastatic disease remains poor. In recent studies, punicalagin has reduced the cell viability, angiogenesis, and invasion in cell culture trials. The aim of this study was to examine the effects of punicalagin on osteosarcomas in a 3D in vivo tumor model. Human osteosarcoma biopsies and SaOs-2 and MG-63 cells, were grown in a 3D in vivo chorioallantoic membrane (CAM) model. After a cultivation period of up to 72 h, the tumors received daily treatment with punicalagin for 4 days. Weight measurements of the CAM tumors were performed, and laser speckle contrast imaging (LSCI) and a deep learning-based image analysis software (CAM Assay Application v.3.1.0) were used to measure angiogenesis. HE, Ki-67, and Caspase-3 staining was performed after explantation. The osteosarcoma cell lines SaOs-2 and MG-63 and osteosarcoma patient tissue displayed satisfactory growth patterns on the CAM. Treatment with punicalagin decreased tumor weight, proliferation, and tumor-induced angiogenesis, and the tumor tissue showed pro-apoptotic characteristics. These results provide a robust foundation for the implementation of further studies and show that punicalagin offers a promising supplementary treatment option for osteosarcoma patients. The 3D in vivo tumor model represents a beneficial model for the testing of anti-cancer therapies

Auswirkungen einer Stützstrebe auf die Flügelmasse und die Flugleistungen am Beispiel der ATR 72-600

Die vorliegende Arbeit untersucht die Annahme nach Torenbeek, nach der die Flügelmasse pauschal um 30 % abnimmt, wenn der Flügel durch eine Stützstrebe entlastet ist. Am Deutschen Zentrum für Luft- und Raumfahrt (DLR) wurde ein Rechenverfahren entwickelt, mit dem es möglich ist, die Flügelmasse bei verschiedenen Strebenwinkeln näherungsweise zu berechnen. Dieses Verfahren wird ausführlich vorgestellt und anschließend in eine Excel-Datei implementiert. Anschließend wird mit ebendieser Datei die Flügelmasse der ATR 72-600 bei verschiedenen (hypothetischen) Strebenwinkeln ermittelt und auch die theoretischen Auswirkungen einer Stützstrebe auf die Flugleistungen untersucht. Zum Schluss wird das Prinzip der virtuellen Kräfte angewendet, um die Rechenergebnisse der DLR-Methode zu verfizieren bzw. zu optimieren.This thesis analyzes Torenbeek’s assumption that a strut-braced wing has 30 % less weight compared to the same wing without strut. At the Deutsches Zentrum für Luft- und Raumfahrt (DLR), they developed a method to approximately calculate the wing weight at different strut angles. This method will be presented and afterwards implemented into an Excel-file. The file will then be used to calculate the wing weight of the ATR 72-600 at different (hypothetical) strut angles. Furthermore, the effects of these different strut configurations on the performance of the aircraft will be considered. Finally, the principle of virtual forces will be applied to verify and/or optimize the results found with the DLR method