Konzept und FE-Modellierung zum Nachweis der erforderlichen Ankerlänge

Conception and FE-modelling for a verification of a sufficient anchor length. Investigations for a verification of a sufficient anchor length at a tied back excavation wall on basis of the Finite-Element-Method (FEM) are presented. With the help from an example it is examined how the modelling of the grout body effects the calculated safety factors. Besides the anchor length also the coarseness of the FEM mesh is varied, in order to score the influence of interface-elements at the grout body on the dependence of the calculation results from the coarseness of the mesh. It is discussed whether the verification of a sufficient anchor length with the FEM could be examined by a plain strain calculation and how the deficiencies compared to the 3-dimensional reality could be adjusted via a fictitious shortening of the anchor. Considerations are following, concerning handling of the unavoid-able uncertainties at the verification of the sufficient anchor length. These considerations could be used for such a verification on basis of the FEM. Finally, a detailed conception for the verification of a sufficient anchor length on basis of the FEM is presented. The conception contains the findings from the calculated examples as well as the mentioned considerations on the uncertainties.     

Konrad Zuse und die Baustatik — Zur Formierung der Computerstatik (Teil 2)

Konrad Zuse verallgemeinerte das 1934 mit seiner Studienarbeit am Beispiel der statisch unbestimmten Analyse entwickelte programmförmige Rechenschemata 1936 zum “Verfahren des Rechenplanes oder Programms” (Konrad Zuse). Von 1936 bis 1941 entfaltete er dieses Verfahren in erster Linie für die Bau‐ und Flugzeugstatik. Diese numerischen Rechenpläne bildeten eine wesentliche Seite der historisch‐logischen Entwicklung von Zuses programmgesteuerten Rechenautomaten Z1 (1938) und Z3 (1941). Mit den numerischen Rechenplänen ist auch die erste Stufe der Initialphase der Computerstatik benannt. Ihre zweite Stufe hebt mit Zuses Plankalkül an (1942—1949) — der ersten “Plattform für Softwareentwicklung” (Peter Jan Pahl ) — in dessen Zentrum sein allgemeines Konzept des Rechnens steht, das Zuse aus dem Kalkül‐Begriff der Mathematik entwickelt und das Zahlenrechnen als Sonderfall enthält. Die beiden Stufen werden im Folgenden eingehend dargestellt und durch eine exemplarische Skizze der um 1950 einsetzenden Konstituierungsphase der Computerstatik abgerundet. Konrad Zuse and the theory of structures — on the formation of computational mechanics (part 2). It was in 1936 that Konrad Zuse generalised the program‐type calculation scheme, which he had developed in his student project of 1934 using the example of the statically indeterminate analysis, to form the ”computing plan or program method” (Konrad Zuse). Between 1936 and 1941 he continued to develop this method, in the first place for structural and aviation engineering. These numerical computing plans formed one fundamental element in the historico‐logical evolution of Zuse’s program‐controlled automatic computers Z1 (1938) and Z3 (1941). The numerical computing plans also mark the first step in the initial phase of computational mechanics. The second step (1942—1949) began with Zuse’s ”Plankalkül” (Calculus of Programs) — the first ”software development platform” (Peter Jan Pahl) —, the heart of which is his general calculation concept, which Zuse developed from the formal system concept of mathematics and which contains numerical computation as a special case. Both of these steps are presented in detail below and rounded off with an illustrative outline of the constitution phase of computational mechanics which began around 1950.     

Konrad Zuse und die Baustatik — Zur Vorgeschichte der Computerstatik (Teil 1)

Von der Historiographie der Informatik wurde der bahnbrechende Beitrag Konrad Zuses (1910—1995) bei der Entwicklung des Computers in den letzten Jahren umfassend herausgearbeitet ([1] bis [4]). Dagegen wurde der Zusammenhang seiner Rechnerentwicklung mit dem damaligen Stand der Baustatik nur ansatzweise analysiert ([5] bis [11]). Die historisch interessierten Informatiker und Bauingenieure gaben sich mit der Feststellung zufrieden, dass das umfangreiche statisch unbestimmte Rechnen um 1930 Zuse wesentlich motivierte. Des Weiteren bedienten populäre Darstellungen des Lebenswerkes von Zuse und viele der Laudationes auf ihn die vorherrschende Abneigung gegen das Rechnen im Allgemeinen und das statische Rechnen im Besonderen. So stimmen zum 100. Geburtstag von Zuse manche Zeitgenossen ein in den Chor “Er war zu faul zum Rechnen“ und schließen kurz, dass er deshalb den Computer erfunden hätte. Vor der Folie der Kalkülisierung der Baustatik sowie der Rationa lisierung und Schematisierung des statischen Rechnens im ersten Drittel des vorigen Jahrhunderts wird der Einfluß der Berliner Schule der Baustatik (s. [9, S. 389—404]) auf Zuses Ideenkreis um die Automatisierung des Rechnens bis 1935 herausgearbeitet. Als Prolegomenon von Zuses Rechnerentwicklung kann seine Mitte 1934 vollendete Studienarbeit über die Berechnung eines 9fach statisch unbestimmten Systems gelten. Aus der Perspektive des operativen Symbolgebrauchs in der Konsolidierungsperiode der Baustatik (1900—1950) erscheint ihre Geschichte in diesem Zeitraum als Vorgeschichte der Computerstatik. Konrad Zuse and the theory of structures — a prologue to computational mechanics (part 1). The pioneering role of Konrad Zuse (1910—1995) in the development of the computer has been covered comprehensively in the historical study of informatics in recent years ([1] to [4]). However, the relationship between his computer development work and the situation in theory of structures at the time has so far been given only a rudimentary analysis ([5] to [11]). Those computer scientists and construction engineers interested in the history of their professions have seemingly been happy just to know that the need for extensive statically indeterminate computations around 1930 were Zuse’s main motivation. Furthermore, popular accounts of his life’s work and many of the tributes paid to him exploit the fact that there was a widespread aversion to calculations in general and structural calculations in particular. Thus, on the 100th anniversary of Zuse’s birth, some contemporaries could be heard joining in with the “he was too lazy to calculate” chorus, and quickly coming to the conclusion that this was the reason why he invented the computer. The influence of the Berlin school of structural theory (s. [9, S. 389— 404]) on Zuse’s notions surrounding the automation of computa tions up until 1935 is shown here against the background of the introduction of formalised theory into structural analysis plus the rationalisation and schematisation of structural calculations in the first 30 or so years of the 20th century. Zuse’s project concerning the calculation of a system with nine degrees of static indeter minacy, which was completed in 1934 while he was a student, can be regarded as a preface to his later computer development. Looked at from the perspective of the practical use of symbols during the consolidation period of theory of structures (1900—1950), the history of structural analysis over these years seems to be a prologue to computational mechanics.     

Targeting Cell Death Mechanism Specifically in Triple Negative Breast Cancer Cell Lines

Triple negative breast cancer (TNBC) is currently associated with a lack of treatment options. Arsenic derivatives have shown antitumoral activity both in vitro and in vivo; however, their mode of action is not completely understood. In this work we evaluate the response to arsenate of the double positive MCF-7 breast cancer cell line as well as of two different TNBC cell lines, Hs578T and MDA-MB-231. Multimodal experiments were conducted to this end, using functional assays and microarrays. Arsenate was found to induce cytoskeletal alteration, autophagy and apoptosis in TNBC cells, and moderate effects in MCF-7 cells. Gene expression analysis showed that the TNBC cell lines’ response to arsenate was more prominent in the G2M checkpoint, autophagy and apoptosis compared to the Human Mammary Epithelial Cells (HMEC) and MCF-7 cell lines. We confirmed the downregulation of anti-apoptotic genes (MCL1, BCL2, TGFβ1 and CCND1) by qRT-PCR, and on the protein level, for TGFβ2, by ELISA. Insight into the mode of action of arsenate in TNBC cell lines it is provided, and we concluded that TNBC and non-TNBC cell lines reacted differently to arsenate treatment in this particular experimental setup. We suggest the future research of arsenate as a treatment strategy against TNBC.