Global ETD Search

1	Architecture and core of the small ribosomal subunit Gulen, Burak 27 May 2016 (has links) The ribosome is one of the most universal molecular machinery, synthesizing proteins in all living systems. The small ribosomal subunit plays a crucial role in decoding the messenger RNA during translation. We propose and validate a new architectural model of the ribosomal small subunit, with broad implications for function, biogenesis and evolution. We define an rRNA domain: compact and modular, stabilized by self-consistent molecular interactions, with ability to fold autonomously when it is isolated from surrounding RNA or protein. Each rRNA helix must be allocated uniquely to a single domain. These criteria identify a core domain of small subunit rRNA (domain A), which acts as a hub, linking to all other domains by A-form helical spokes. Experimental characterization of isolated domain A, and mutations and truncations of it, by methods including selective 2’OH acylation analyzed by primer extension and circular dichroism spectroscopy are consistent with autonomous folding, and therefore classification as a domain. We show that the domain concept is applicable and useful for understanding the small ribosomal subunit. Our results support the utility of the concept of the domain as applied to at least some RNAs, the interdependence of the elements of domain A, and its ability to fold autonomously. Moreover, domain A, which exhibits elements of tRNA mimicry, is the essential core of the small ribosomal subunit. Understanding the structure and dynamics of domain A will provide valuable insight into the translational machinery. Ribosome Small subunit Central pseudoknot SSU Translation tRNA mimicry Ribosomal evolution SHAPE S5 S12
2	Biocatalysis for oxidation of naphthalene to 1-naphthol: liquid-liquid biphasic systems and solvent tolerant strains Garikipati Satya Venkata, Bhaskara Janardhan 01 May 2009 (has links) Biocatalysis involves the use of enzymes to perform stereo- and enantio-specific reactions. One of the reactions where biocatalysis is a valuable technology is oxidation of naphthalene to 1-naphthol using Toluene ortho-Monooxygenase (TOM) variant TmoA3 V106A, also known as TOM-Green. Whole-cell biocatalysis in a water-organic solvent biphasic system was used to minimize naphthalene and 1-naphthol toxicity, and to increase substrate loading. Recombinant Escherichia coli TG1 cells expressing TOM-Green were used for biphasic biocatalysis and lauryl acetate gave best results among the solvents tested. On a constant volume basis, 8 - fold improvement in 1-naphthol production was achieved using biphasic systems compared to biotransformation in aqueous medium. The organic phase was optimized by studying the effects of organic phase ratio and naphthalene concentration in the organic phase. The efficiency of biocatalysis was further improved by application of a solvent tolerant strain Pseudomonas putida S12. P. putida S12 is solvent tolerant owing to its two adaptive mechanisms: outer membrane modification and solvent extrusion using solvent resistant pump srpABC. P. putida S12, in addition to its tolerance to various organic solvents, showed better tolerance to naphthalene compared to E. coli TG1 strain expressing TOM-Green. Application of solvent tolerant P. putida S12 further improved 1-naphthol productivity by approximately 42%. Solvent tolerance of P. putida S12 was further analyzed by transferring its tolerance to a solvent sensitive E. coli strain by transfer of solvent resistant pump srpABC genes. Engineered E. coli strain bearing srpABC genes either in low-copy number plasmid or high-copy number plasmid grew in the presence of a saturated toluene concentration. Engineered E. coli strains were also more tolerant to toxic solvents, e. g., decanol and hexane, compared to the control E. coli strain without srpABC genes. The expression of solvent resistant pump genes was confirmed by Reverse Transcriptase PCR analysis. The main drawbacks of biocatalysis for production of chemicals were addressed and approaches to minimize the drawbacks have been presented. The production of 1-naphthol was significantly improved using biocatalysis in liquid-liquid biphasic systems. 1-NAPHTHOL BIOCATALYSIS BIPHASIC SYSTEM LAURYL ACETATE PSEUDOMONAS PUTIDA S12 SOLVENT TOLERANCE Chemical Engineering
3	Fluidic Tuning of a Four-Arm Spiral-Based Frequency Selective Surface Wells, Elizabeth Christine 2011 May 1900 (has links) Frequency selective surfaces (FSSs) provide a variety of spatial filtering functions, such as band-pass or band-stop properties in a radome or other multilayer structure. This filtering is typically achieved through closely-spaced periodic arrangements of metallic shapes on top of a dielectric substrate (or within a stack of dielectric materials). In most cases, the unit cell size, its shape, the substrate parameters, and the inter-element spacing collectively impact the response of the FSS. Expanding this design space to include reconfigurable FSSs provides opportunities for applications requiring frequency agility and/or other properties. Tuning can also enable operation over a potentially wider range of frequencies and can in some cases be used as a loading mechanism or quasi-ground plane. Many technologies have been considered for this type of agility (RF MEMS, PIN diodes, etc.). This includes the recent use of microfluidics and dispersions of nanoparticles, or fluids with controllable dielectrics, which have entered the design space of numerous other EM applications including stub-tuners, antennas, and filters. In this work they provide a material based approach to reconfiguring an FSS. An FSS based on a four-arm spiral with tunable band-stop characteristics is presented in this work. A thin colloidal dispersion above each element provides this tuning capability. The radial expansion and contraction of this dispersion, as well as the variable permittivity of the dispersion, are used to load each element individually. This design incorporates thin fluidic channels within a PDMS layer below the substrate leading to individual unit cells that provide a closed pressure-driven subsystem that contains the dispersion. With the capability to individually control each cell, groups of cells can be locally altered (individually or in groups) to create gratings and other electromagnetically agile features across the surface or within the volume of a radome or other covering. Simulations and measurements of an S-band tunable design using colloidal Barium Strontium Titanate dispersed Silicone oil are provided to demonstrate the capability to adjust the stop-band characteristics of the FSS across the S-band. FSS Frequency Selective Surface RF Radio Frequency BSTO Barium Strontium Titanate Oxide Si Silicone PDMS Polydimethylsiloxane φ Volume Fraction ε Permittivity dB Decibels GHz Gigahertz Freq Frequency S12 Reverse Voltage Gain or Transmission IL Insertion Loss
4	Funny games Pühler, Simon 22 October 2014 (has links) "FUNNY GAMES. Spielräume des Sadomasochismus in Film und Medien" ist der Versuch, eine Geschichte medialer Schmerzlust zu rekonstruieren – in etwa von 1789 bis heute. Neben klassischer SM-Literatur sind es Spielfilme wie VIDEODROME (1983), FALSCHER BEKENNER (2005), THE HURT LOCKER (2008) oder SHORTBUS (2006), in denen modernes Schmerzlust-Empfinden und -Begehren offenbar wird. Die Untersuchung richtet sich dabei auf Konzepte technoimaginärer Wunsch- und Höllenmaschinen, dynamisierte Ich-Apparate, wie sie Donatien-Alphonse-François de Sade, Leopold und Wanda von Sacher-Masoch, Ernst Kapp, Sigmund Freud, Daniel Paul Schreber, Jacques Lacan, Gilles Deleuze und Félix Guattari, David Cronenberg, Michael Haneke, Kathryn Bigelow u.v.a. im Medienumfeld ihrer Zeit individuell erleben und auf ihre je eigene Art – meist sehr fantasiereich – bearbeiten. Der vorliegende Entwurf, medienarchäologische Spurensicherung und gleichsam Test-Spiel, ist vor allem eine Einladung zum Mitmachen: Beim obsessiven Durchschreiten virtueller (Alptraum-)Welten und realer Körper negative und positive Lust zu erfahren, sich neuen Sinnesreizqualitäten zu öffnen, um schließlich Mehr-Lust und -Wissen zu erwerben. Anti-Ödipus als interaktives Video(bei)spiel. Als Analysetools haben sich Erkenntnisse aus der (strukturalen) Psychoanalyse, der (technischen) Medienwissenschaft, (Film-)Philosophie, der Gender-, Gewalt-, Fetisch- und (kulturwissenschaftlichen) Spieltheorie als hilfreich erwiesen, um dem Geheimnis und Rätsel sadomasochistischer Schmerzlust – und ihrer crash-Medien – ein wenig näher zu kommen. / "FUNNY GAMES. Spielräume des Sadomasochismus in Film und Medien" aims to reconstruct a history of pleasure and gratification through pain in the media since the end of the eighteenth century. In addition to classical sado-masochistic literature, the thesis focuses on movies in which modern forms of experiencing and desiring pain such as VIDEODROME (1983), I AM GUILTY (2005), THE HURT LOCKER (2008) and SHORTBUS (2006) manifest themselves. Central to the study are concepts of techno-imaginary wish machines and infernal devices, dynamised ego-apparatuses, that are experienced and expressed through the media of their time by writers, philosophers, psychoanalysts and film directors such as Donatien-Alphonse-François de Sade, Leopold and Wanda von Sacher-Masoch, Ernst Kapp, Sigmund Freud, Daniel Paul Schreber, Jacques Lacan, Gilles Deleuze and Félix Guattari, David Cronenberg, Michael Haneke and Kathryn Bigelow. The present study, an attempt to secure the medial evidence and try it out at the same time, is meant most of all as an invitation to participate: to experience positive desire and lust while obsessively progressing through virtual worlds of dreams and nightmares and the real world of the human body, to open oneself to new experiences in order to gain both new knowledge and new desires. Anti-Oedipus as a textual videogame. The analytical tools employed in this study include findings from (structural) psychoanalysis, media sciences, (movie) philosophy, gender theory, the theory of violence, fetish theory and game theory as applied in cultural studies. They have proven to be very helpful in illuminating at least some aspects of the mystery that is the sado-masochist desire for pain. Sigmund Freud Medien Schmerz Sadomasochismus SM Spiel Raum Lust Funny Games Videodrome Falscher Bekenner Shortbus Donatien-Alphonse-François de Sade Leopold von Sacher-Masoch Ernst Kapp Daniel Paul Schreber Jacques Lacan Gilles Deleuze Félix Guattari David Cronenberg Michael Haneke Kinji Fukasaku Kathryn Bigelow Christoph Hochhäusler John Cameron Mitchell media Sadomasochism SM pleasure pain Funny Games Videodrome Shortbus Donatien-Alphonse-François de Sade Leopold von Sacher-Masoch Ernst Kapp Sigmund Freud Daniel Paul Schreber Jacques Lacan Gilles Deleuze Félix Guattari David Cronenberg Michael Haneke Kinji Fukasaku Kathryn Bigelow Christoph Hochhäusler John Cameron Mitchell 49 Theater, Tanz, Film AP 53950 AP 50300 S12 ddc:791

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