Cycloadditionen am Azulensystem

Cycloadditionen am Azulensystem waren bisher nicht bekannt. Vielmehr reagiert Azulen z. B. mit Maleinsäureanhydrid unter „addierender Substitution" zum 1-Azulenyl- bernsteinsäureanhydrid und mit Tetracyanäthylen zum 1-Tricyanvinyl-azulen[¹]

Significance of intra-fractional motion for pancreatic patients treated with charged particles

Background; Uncertainties associated with the delivery of treatment to moving organs might compromise the accuracy of treatment. This study explores the impact of intra-fractional anatomical changes in pancreatic patients treated with charged particles delivered using a scanning beam. The aim of this paper is to define the potential source of uncertainties, quantify their effect, and to define clinically feasible strategies to reduce them. Methods: The study included 14 patients treated at our facility with charged particles (protons or 12C) using intensity modulated particle therapy (IMPT). Treatment plans were optimized using the Treatment Planning System (TPS) Syngo® RT Planning. The pre-treatment dose distribution under motion (4D) was simulated using the TPS TRiP4D and the dose delivered for some of the treatment fractions was reconstructed. The volume receiving at least 95% of the prescribed dose (V95CTV) and the target dose homogeneity were evaluated. The results from the 4D dose calculations were compared with dose distributions in the static case and its variation correlated with the internal motion amplitude and plan modulation, through the Pearson correlation coefficient, as well the significant p-value. The concept of the modulation index (MI) was introduced to assess the degree of modulation of IMPT plans, through the quantification of intensity gradients between neighboring pencil beams. Results: The induced breathing motion together with dynamic beam delivery results in an interplay effect, which affects the homogeneity and target coverage of the dose distribution. This effect is stronger (∆V95CTV > 10%) for patients with tumor motion amplitude above 5 mm and a highly modulated dose distribution between and within fields. The MI combined with the internal motion amplitude is shown to correlate with the target dose degradation and a lack of plan robustness against range and positioning uncertainties. Conclusions: Under internal motion the use of inhomogeneous plans results in a decrease in the dose homogeneity and target coverage of dose distributions in comparison to the static case. Plan robustness can be improved by using multiple beams and avoiding beam entrance directions susceptible to density changes. 4D dose calculations support the selection of the most suitable plan for the specific patient’s anatomy

Cycloadditions to the Azulene System

Cycloadditions to the azulene system have not hitherto been observed. Instead, azulene reacts, e.g., with maleic anhydride via an "addition-substitution route" to give 1-azulenylsuccinic anhydride and with tetracyanoethylene to yield 1-tricy-anovinylazulene[¹]

Concept and Development of a Potent Topical Corticosteroid

In a rational approach to identify an ultrapotent compound for the treatment of therapy-resistant dermatoses, Weirich's modification of McKenzie's skin vasoconstriction assay (HVK test) has been used as the essential selection criteria. In a primary phase, a quantitative relationship between the HVK activity of 25 derivatives of corticosterone substituted in various positions of the skeleton, and their lipophilicity (log P) was established. The specific lipophilicity-independent interactions were accounted for by the inclusion of 'indicator variables' into the regression analysis. The highly significant results allowed to localize an optimal log P range and to identify the influence of various substituents. In a next phase, the evidence of the first HVK analysis was refined by considering 28 additional compounds. On the basis of the confirmed facts, six 21-chloro-6α-fluoro compounds were specifically synthesized and submitted to dermatopharmacological testing. Finally, CGP 14458 (= 2l-chloro-6α,9-difluoro-11β-hydroxy-16β-methyl-3,20-dioxopregna-1,4-dien-17α-yl propionate) which was predicted to be the most potent representative of these series, whose synthesis is described in detail, showed indeed to be the most effective compound. Clinical trials with this compound – halobetasol propionate/Ultravate® (ulobetasol/Miracorten®) – confirmed its unique efficacy, especially in the treatment of severe, chronic plaque psoriasis

Comparison of intensity modulated radiotherapy (IMRT) with intensity modulated particle therapy (IMPT) using fixed beams or an ion gantry for the treatment of patients with skull base meningiomas

<p>Abstract</p> <p>Background</p> <p>To examine the potential improvement in treatment planning for patients with skull base meningioma using IMRT compared to carbon ion or proton beams with and without a gantry.</p> <p>Methods</p> <p>Five patients originally treated with photon IMRT were selected for the study. Ion beams were chosen using a horizontal beam or an ion gantry. Intensity controlled raster scanning and the intensity modulated particle therapy mode were used for plan optimization. The evaluation included analysis of dose-volume histograms of the target volumes and organs at risk.</p> <p>Results</p> <p>In comparison with carbon and proton beams only with horizontal beams, carbon ion treatment plans could spare the OARs more and concentrated on the target volumes more than proton and photon IMRT treatment plans. Using only a horizontal fixed beam, satisfactory plans could be achieved for skull base tumors.</p> <p>Conclusion</p> <p>The results of the case studies showed that using IMPT has the potential to overcome the lack of a gantry for skull base tumors. Carbon ion plans offered slightly better dose distributions than proton plans, but the differences were not clinically significant with established dose prescription concepts.</p

Social Class

Discussion of class structure in fifth-century Athens, historical constitution of theater audiences, and the changes in the comic representation of class antagonism from Aristophanes to Menander

Cycloadditions to the Azulene System

Cycloadditions to the azulene system have not hitherto been observed. Instead, azulene reacts, e.g., with maleic anhydride via an "addition-substitution route" to give 1-azulenylsuccinic anhydride and with tetracyanoethylene to yield 1-tricy-anovinylazulene[¹]