Portrait of Alfred Lichtenstein with his flute.

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Portrait of Alfred Lichtenstein with his flute; New York.

Handwritten dedication signed by Lichtenstein

Alfred Lichtenstein, self-portrait with Hasselblad camera.

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Family portrait with Alfred Lichtenstein, his first wife Gerda, unidentified others (maman, tante, oncle, soeur).

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Alfred Lichtenstein with his daughter Sylvia; Buenos Aires.

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Alfred Lichtenstein with his first wife Gerda and their daughter Sylvia seated on a park bench; Buenos Aires.

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Alfred Lichtenstein with his first wife Gerda; Parque Palermo, Buenos Aires.

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Portrait of Alfred Lichtenstein's second wife Georgette Wegh; New York.

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Portrait of Alfred Lichtenstein's second wife Georgette Wegh; Berlin.

Handwritten dedication signed by Georgette Wegh

Alfred Lichtenstein with his first wife Gerda; Parque Palermo, Buenos Aires.

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Studio portraits of Alfred Lichtenstein with his flute; New York.

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Portrait of Alfred Timme; Employee of Mendelssohn Bank, Berlin Portraits Men

"25.98.1884. Alfred Timme geb. 9.12.1860. pens. 31.12.1927"

Crystal structure of an intermolecular 2:1 complex between adenine and thymine.Evidence for both Hoogsteen and `quasi-Watson-Crick' interactions

The titled complex, obtained by co-crystallization (EtOH/25 degrees C),is apparently the only known complex of the free bases. Its crystal structure, as determined by X-ray diffraction at both 90 K and 313 K, showed that one A-T pair involves a Hoogsteen interaction, and the other a Watson-Crick interaction but only with respect to the adenine unit. The absence of a clear-cut Watson-Crick base pair raises intriguing questions about the basis of the DNA double helix. (C) 2010 Elsevier Ltd. All rights reserved.

Beyond Watson and Crick : programming the self-assembly and reconfiguration of DNA nanostructures based on stacking interactions

Life is the result of the execution of molecular programs: like how an embryo is fated to become a human or a whale, or how a person’s appearance is inherited from their parents, many biological phenomena are governed by genetic programs written in DNA molecules. At the core of such programs is the highly reliable base pairing interaction between nucleic acids. DNA nanotechnology exploits the programming power of DNA to build artificial nanostructures, molecular computers, and nanomachines. In particular, DNA origami—which is a simple yet versatile technique that allows one to create various nanoscale shapes and patterns—is at the heart of the technology. In this thesis, I describe the development of programmable self-assembly and reconfiguration of DNA origami nanostructures based on a unique strategy: rather than relying on Watson-Crick base pairing, we developed programmable bonds via the geometric arrangement of stacking interactions, which we termed stacking bonds. We further demonstrated that such bonds can be dynamically reconfigurable.

The first part of this thesis describes the design and implementation of stacking bonds. Our work addresses the fundamental question of whether one can create diverse bond types out of a single kind of attractive interaction—a question first posed implicitly by Francis Crick while seeking a deeper understanding of the origin of life and primitive genetic code. For the creation of multiple specific bonds, we used two different approaches: binary coding and shape coding of geometric arrangement of stacking interaction units, which are called blunt ends. To construct a bond space for each approach, we performed a systematic search using a computer algorithm. We used orthogonal bonds to experimentally implement the connection of five distinct DNA origami nanostructures. We also programmed the bonds to control cis/trans configuration between asymmetric nanostructures.

The second part of this thesis describes the large-scale self-assembly of DNA origami into two-dimensional checkerboard-pattern crystals via surface diffusion. We developed a protocol where the diffusion of DNA origami occurs on a substrate and is dynamically controlled by changing the cationic condition of the system. We used stacking interactions to mediate connections between the origami, because of their potential for reconfiguring during the assembly process. Assembling DNA nanostructures directly on substrate surfaces can benefit nano/microfabrication processes by eliminating a pattern transfer step. At the same time, the use of DNA origami allows high complexity and unique addressability with six-nanometer resolution within each structural unit.

The third part of this thesis describes the use of stacking bonds as dynamically breakable bonds. To break the bonds, we used biological machinery called the ParMRC system extracted from bacteria. The system ensures that, when a cell divides, each daughter cell gets one copy of the cell’s DNA by actively pushing each copy to the opposite poles of the cell. We demonstrate dynamically expandable nanostructures, which makes stacking bonds a promising candidate for reconfigurable connectors for nanoscale machine parts.

O périplo da formação de Berardo Viola e de Franz Biberkopf: um estudo do Bildungsroman em Fontamara, de Ignazio Silone, e em Berlin Alexanderplatz, de Alfred Döblin

Esta pesquisa analisa Berlin Alexanderplatz (1929), de Alfred Döblin, e Fontamara (1933), de Ignazio Silone, baseada nas novas concepções sobre o Bildungsroman, ou romance de formação, estabelecidas pelos olhares atualizadores de teóricos do século XX. O Bildungsroman, modalidade narrativa surgida no século XVIII, cuja obra paradigma é Os anos de aprendizado de Wilhelm Meister, de Johann Wolfgang Von Goethe, ressalta o desenvolvimento humano, seu processo de amadurecimento e conscientização ao longo de sua trajetória existencial. Os corpora desta dissertação são romances escritos no período conflituoso do entreguerras, cujo enredo destaca a luta interior e exterior das personagens em sobreviver àquele período e a consequente tomada de consciência adquirida neste percurso. O périplo metafórico vivenciado pelos protagonistas, de Fontamara, Berardo Viola, e de Berlin Alexanderplatz, Franz Biberkopf, tem como consequência uma nova consciência política, para o primeiro protagonista, e uma nova consciência social, para o segundo. O caminho formativo dos protagonistas constitui-se de maneira diversa. O objetivo deste estudo é, portanto, analisar como se realiza o processo de formação de Berardo Viola e Franz Biberkopf, apontando identidades e diferenças entre os dois processos, e, por fim, apontando como tais romances podem atualizar o conceito de Bildungsroman na história literária