Nuclear halo of a 177 MeV proton beam in water: theory, measurement and parameterization

The dose distribution of a monoenergetic pencil beam in water consists of an electromagnetic "core", a "halo" from charged nuclear secondaries, and a much larger "aura" from neutral secondaries. These regions overlap, but each has distinct spatial characteristics. We have measured the core/halo using a 177MeV test beam offset in a water tank. The beam monitor was a fluence calibrated plane parallel ionization chamber (IC) and the field chamber, a dose calibrated Exradin T1, so the dose measurements are absolute (MeV/g/p). We performed depth-dose scans at ten displacements from the beam axis ranging from 0 to 10cm. The dose spans five orders of magnitude, and the transition from halo to aura is clearly visible. We have performed model-dependent (MD) and model-independent (MI) fits to the data. The MD fit separates the dose into core, elastic/inelastic nuclear, nonelastic nuclear and aura terms, and achieves a global rms measurement/fit ratio of 15%. The MI fit uses cubic splines and the same ratio is 9%. We review the literature, in particular the use of Pedroni's parametrization of the core/halo. Several papers improve on his Gaussian transverse distribution of the halo, but all retain his T(w), the radial integral of the depth-dose multiplying both the core and halo terms and motivating measurements with large "Bragg peak chambers" (BPCs). We argue that this use of T(w), which by its definition includes energy deposition by nuclear secondaries, is incorrect. T(w) should be replaced in the core term, and in at least part of the halo, by a purely electromagnetic mass stopping power. BPC measurements are unnecessary, and irrelevant to parameterizing the pencil beam.Comment: 55 pages, 4 tables, 29 figure

Zum Tragverhalten von Carbonbeton unter Ermüdungsbeanspruchung

Die Anzahl an Brücken aus Textil- bzw. Carbonbeton wächst stetig und umso dringender wird die Fragestellung nach einer sicheren Ermüdungsbemessung von Carbonbeton. Die bloße Einführung von Abminderungsfaktoren als Widerstand gegen die Ermüdungsbelastung ist hierbei keine Option. Für eine wirtschaftliche Bemessung von Carbonbeton unter Zugschwellbelastung ist ein materialgerechtes Bemessungskonzept vonnöten, welches zunächst eine umfangreiche Untersuchung des Materialverhaltens unter Ermüdungsbelastung erfordert. Hierzu leistet die vorliegende Arbeit einen essentiellen Beitrag. Zunächst wird dabei der für die durchgeführten Untersuchungen relevante Wissensstand zusammengefasst. Anschließend werden umfangreiche Ermüdungsuntersuchungen vorgestellt, welche an zwei verschiedenen, marktüblichen Materialkombinationen durchgeführt wurden. Dabei wurden sowohl das Zug- als auch das Verbundtragverhalten von Carbonbeton unter Zugschwellbelastung betrachtet. Neben den erreichbaren Schwingspielzahlen und Resttragfähigkeiten von Durchläufern wurden auch das Spannungs-Dehnungs- bzw. -Verformungs-Verhalten, die Veränderung der Gestalt der Hystereseschleifen, die Probekörperdehnungen bzw. -verformungen und die Probekörpersteifigkeiten während der Ermüdungsbelastung untersucht. Anhand der erzielten Untersuchungsergebnisse wird schlussendlich ein Vorschlag für ein Bemessungskonzept für Carbonbeton unter Zugschwellbeanspruchung zusammengestellt. Die in der vorliegenden Arbeit erzielten Ergebnisse tragen somit dazu bei, ein grundlegendes Verständnis für das Materialverhalten von Carbonbeton bei Ermüdungsbelastung zu erhalten und die Ermüdungsbemessung für die untersuchten Materialien durchzuführen. Die Übertragbarkeit der Ergebnisse auf weitere Materialkombinationen ist in weiterführenden Untersuchungen zu überprüfen

Handbuch Bürgerbus

HANDBUCH BÜRGERBUS Handbuch Bürgerbus / Wagner, Petra-Juliane (Rights reserved) ( -

Systematic review on diabetes mellitus and dental implants: an update

Purpose Dental implant surgery was developed to be the most suitable and comfortable instrument for dental and oral rehabilitation in the past decades, but with increasing numbers of inserted implants, complications are becoming more common. Methods A systematic literature research based on the PRISMA statement was conducted to answer the PICO question "Do diabetic patients with dental implants have a higher complication rate in comparison to healthy controls?". We included 40 clinical studies and 16 publications of aggregated literature in this systematic review. Results We conclude that patients with poorly controlled diabetes mellitus suffer more often from peri-implantitis, especially in the post-implantation time. Moreover, these patients show higher implant loss rates than healthy individuals in long term. Whereas, under controlled conditions success rates are similar. Perioperative anti-infective therapy, such as the supportive administration of antibiotics and chlorhexidine, is the standard nowadays as it seems to improve implant success. Only few studies regarding dental implants in patients with prediabetic conditions are available, indicating a possible negative effect on developing peri-implant diseases but no influence on implant survival. Conclusion Dental implant procedures represent a safe way of oral rehabilitation in patients with prediabetes or diabetes mellitus, as long as appropriate precautions can be adhered to. Accordingly, under controlled conditions there is still no contraindication for dental implant surgery in patients with diabetes mellitus or prediabetic conditions

Abscisic acid induces somatic embryogenesis and enables the capture of high-value genotypes in Douglas fir (Pseudotsuga menziesii [MIRB.] Franco)

Douglas fir (Pseudotsuga menziesii) is one of Europe’s most important non-native tree species due to its drought tolerance as well as timber quality and yield. To obtain superior seed from selected parental trees, breeding programs had been established in seed orchards. Douglas fir seed is used as source material for somatic embryogenesis with the aim to select elite genotypes invaluable for clonal mass propagation. To improve given protocols for somatic embryo initiation, we used immature Douglas fir zygotic embryos as explants and abscisic acid (ABA) as plant growth regulator in contrast to the application of auxins and cytokinins. With ABA supplementation, induction frequencies were slightly but in mean higher than with auxin/cytokinin, showing also a strong genotype effect. This offered the possibility to capture SE cultures from otherwise recalcitrant crosses. Furthermore, we observed remarkable differences between the two sets of plant growth regulators concerning the morphological development of the explants, including the absence of non-embryogenic callus by using ABA as inducer. This simplifies the detection of events and the handling of the obtained cultures. Nevertheless, a histological approach suggested, that the same competent cells are addressed by the different hormonal stimulation. Besides, we studied the influence of different points in time of cone harvest, two different basal media and different genetic backgrounds of the explants as well as the maturation ability of the induced embryogenic cultures. In sum, we were able to improve the first steps of somatic embryogenesis and to maintain a significantly higher number of high-value genotypes.Peer Reviewe

Chemie im naturwissenschaftlichen Unterricht: Chemie im Schulgarten : eine neue experimentelle Unterrichtskonzeption für die Orientierungsstufe

Mit dem Leitziel, das Unterrichtsfach Chemie im fächerübergreifenden Fach Naturwissenschaften in der Orientierungsstufe zu stärken, ist im Zuge dieser Arbeit eine Konzeption entstanden, deren grundlegendes Element der wiederentdeckte Schulgarten ist. Auf konzeptioneller Ebene wurden dazu einfache Definitionen für die wichtigsten Begriffe formuliert sowie leicht verständliche und unterstützende Abbildungen entwickelt. Auf der praktischen Ebene wurden daher Experimente für die Orientierungsstufe optimiert und neu entworfen.The aim of this work was to develop a didactical concept for the integrative class called Naturwissenschaften, that empowers principals and concepts of chemistry classes build upon the school garden as the basic element. To do that, intelligible graphics for important terms and simple definitions were developed to support the experiment as one of the main elements of chemistry. Some experiments were optimized, others were completely new developed

Fracture strength test of digitally produced ceramic-filled and unfilled dental resin restorations via 3d printing : an in vitro study

Purpose of this study was to investigate the mechanical efficiency of 3D-printed permanent and provisional implant cemented fixed bridges produced via CAD/CAM technology using an interim and a permanent ceramic filled hybrid material. Two groups with t

O Trabalho de Assistência Pedagógica na Universidade: a Experiência da UNISUL

Este trabalho consiste em um relato da experiência da Universidade do Sul de Santa Catarina (UNISUL) na implantação do serviço de assistência pedagógica nos cursos de graduação. Atualmente, os cursos de graduação da universidade estão agrupados por Unidades Acadêmicas (UnAs), de acordo com as áreas de conhecimento a que se relacionam, com estudantes matriculados, resultados econômico-financeiros apresentados e com localização geográfica das atividades de ensino. Cada UnA conta com o serviço de Assistência Pedagógica cuja função é dar suporte às decisões didático-pedagógicas, contribuindo com o processo de implementação dos Projetos Pedagógicos dos Cursos. O objetivo central deste texto é apresentar o caminho percorrido pelo grupo de assistentes pedagógicas contratadas em 2004, 2005 e 2006. Desde o período de capacitação para exercício da função, de imersão nas UnAs, até a fase de constituição do plano de intervenção pedagógica nos respectivos cursos de graduação.. A capacitação para o exercício da função foi planejada e desenvolvida pela Diretoria de Graduação da UNISUL e consistiu-se no estudo dirigido de documentos que regem a gestão pedagógica da universidade, na discussão de casos e na construção coletiva de um plano de trabalho para a imersão das assistentes pedagógicas na realidade dos cursos. Esse plano de trabalho previu uma metodologia para a coleta de dados junto aos coordenadores, docentes e acadêmicos dos cursos, com vistas à leitura do contexto e produção de um plano de intervenção pedagógica. Ao final deste texto , são apresentadas, resumidamente, as práticas pedagógicas identificadas em cada UnA, bem como as propostas de intervenção da assistência pedagógica, ora em implementação

Continuously expanding CAR NK-92 cells display selective cytotoxicity against B-cell leukemia and lymphoma

Background aims Natural killer (NK) cells can rapidly respond to transformed and stressed cells and represent an important effector cell type for adoptive immunotherapy. In addition to donor-derived primary NK cells, continuously expanding cytotoxic cell lines such as NK-92 are being developed for clinical applications. Methods To enhance their therapeutic utility for the treatment of B-cell malignancies, we engineered NK-92 cells by lentiviral gene transfer to express chimeric antigen receptors (CARs) that target CD19 and contain human CD3ζ (CAR 63.z), composite CD28-CD3ζ or CD137-CD3ζ signaling domains (CARs 63.28.z and 63.137.z). Results Exposure of CD19-positive targets to CAR NK-92 cells resulted in formation of conjugates between NK and cancer cells, NK-cell degranulation and selective cytotoxicity toward established B-cell leukemia and lymphoma cells. Likewise, the CAR NK cells displayed targeted cell killing of primary pre-B-ALL blasts that were resistant to parental NK-92. Although all three CAR NK-92 cell variants were functionally active, NK-92/63.137.z cells were less effective than NK-92/63.z and NK-92/63.28.z in cell killing and cytokine production, pointing to differential effects of the costimulatory CD28 and CD137 domains. In a Raji B-cell lymphoma model in NOD-SCID IL2R γnull mice, treatment with NK-92/63.z cells, but not parental NK-92 cells, inhibited disease progression, indicating that selective cytotoxicity was retained in vivo. Conclusions Our data demonstrate that it is feasible to generate CAR-engineered NK-92 cells with potent and selective antitumor activity. These cells may become clinically useful as a continuously expandable off-the-shelf cell therapeutic agent