Synthese und Charakterisierung molekularer Vorläuferverbindungen für den Einsatz in weichen lithographischen Verfahren sowie katalytisch aktiver elementorganischer Gerüstverbindungen

In der vorliegenden Arbeit werden zwei Materialklassen behandelt. Im Hauptteil soll die Synthese und Charakterisierung von molekularen Organo-Silber-Komplexen und deren Einsatz als Tintenmaterial in weichen lithographischen Verfahren beschrieben werden. Dadurch sollen strukturierte Schichten des Komplexes zugänglich sein, welche durch entsprechende Nachbehandlung in elementares Silber umgewandelt werden können, wodurch man schließlich strukturierte Silberelektroden erhält. Der Einsatz solcher strukturierter Elektroden ist für die Weiterentwicklung transparenter elektrisch leitender Schichten, welche man im heutigen Alltag in nahezu jedem elektro-optischen Bauteil findet, essentiell. Bisher beruhen transparente Elektroden vorwiegend auf Zinn dotiertem Indiumoxid (ITO), welches zu den transparent leitfähigen Oxiden (TCOs) gehört und sehr gute elektrische Eigenschaften aufweist. TCOs sind transparente Oxide, welche ihre Leitfähigkeit durch den Einbau von Dotierstoffen und eine damit einhergehende Erzeugung von Störstellen im Kristallgitter erhalten. Aufgrund der anhaltenden Indiumverknappung wird allerdings zunehmend nach Alternativen zu ITO gesucht. Neben weiteren transparent leitfähigen Oxiden wie z.B. Antimon oder Fluor dotiertem Zinnoxid besteht die Möglichkeit, auf leitfähige Polymere, Kohlenstoffmaterialien oder Metalle zurückzugreifen. Diese drei Klassen haben den Vorteil des Einsatzes in flexiblen Bauteilen, welcher bei Verwendung der TCOs aufgrund ihrer Brüchigkeit nur begrenzt möglich ist. Metalle weisen dabei die geringsten elektrischen Widerstände auf und sind daher besonders interessant. Die Herausforderung bei der Verwendung von Metallen liegt allerdings im Erreichen der Transparenz. Durch die Strukturierung der Dünnfilme unterhalb des Wellenlängenbereiches des sichtbaren Lichts kann diese gewährleistet werden. Eine Strukturierung kann zum einen durch z.B. chemische oder physikalische Abscheideprozesse und zum anderen durch die bereits angesprochenen weichen lithographischen Verfahren realisiert werden. Die Entwicklung sogenannter Tinten für solche Druckverfahren auf Basis molekularer Organo-Silber-Komplexe stellt daher ein interessantes Forschungsgebiet dar. In einem zweiten, kleineren Teil dieser Arbeit soll die Synthese neuartiger poröser elementorganischer Gerüstverbindungen (EOFs) auf Basis von Phosphor, Antimon und Bismut und deren katalytische Aktivität vorgestellt werden. Die EOFs wurden erstmals 2008 veröffentlicht und zeichnen sich im Gegensatz zu den ebenfalls bekannten metallorganischen Gerüstverbindungen durch kovalente Element-Kohlenstoff-Bindungen aus. Die Materialien, welche meist auf der Basis von Silanen aufgebaut sind, zeichnen sich durch ihre hohe Stabilität gegenüber Luftsauerstoff und Feuchtigkeit aus und zeigen interessante Eigenschaften in der Wasserdampfphysisorption. Die Adsorption von Wasserdampf findet erst in einem hohen Relativdruckbereich statt, was die stark unpolare Oberfläche der EOFs aufzeigt. Durch diese Eigenschaft weisen die Materialien ein großes Potential für die adsorptive Abtrennung von unpolaren Stoffen aus Wasser oder Luft auf. Durch die Substitution des Siliziums durch Zinn konnte gezeigt werden, dass mit geeigneten Metallpräkursoren ebenfalls EOF-Materialien hergestellt werden können, welche neben den bereits genannten Eigenschaften auch Potential für katalytische Anwendungen zeigen. Dieser Weg sollte in der vorliegenden Arbeit aufgegriffen werden. Durch die Integration der Elemente Phosphor, Antimon und Bismut sollten weitere EOF-Materialien synthetisiert und hinsichtlich ihrer katalytischen Eigenschaften untersucht werden. Ein phosphorhaltiges EOF ist vor allem interessant für postsynthetische Infiltration von Übergangsmetallen. Dadurch können essentielle heterogene Katalysatoren zugänglich sein, welche eine große Bedeutung für die Organokatalyse haben, bei denen bisher vorwiegend die homogenen Analoga verwendet werden. Der Ersatz durch heterogene Katalysatoren würde einen wesentlichen synthetischen Fortschritt mit sich bringen, da diese nach der Reaktion einfach abgetrennt werden können und keine aufwendige Aufarbeitung erforderlich ist

DILEMAS BIOÉTICOS NA CONDUTA DA TRANSFUSÃO SANGUÍNEA

Os profissionais de saúde têm se deparado quotidianamente com conflitos éticos que circundam a escolha entre a conduta terapêutica a ser seguida e o respeito à autonomia do paciente em casos de recusa ao tratamento. Neste trabalho teve-se por objetivo descrever as convicções morais que levam o paciente a recusar a hemotransfusão e as situações nas quais o profissional de saúde, ao se deparar com essa escolha, possa ter segurança para seguir uma conduta distinta da vontade do paciente, e ainda assim respeitar a legislação que rege o princípio da autonomia. Para tanto, foi realizada uma pesquisa de cunho bibliográfico, por meio das bases de dados EBSCO e SCIELO, além de livros e jornais. Segundo Bonamigo (2015, p. 69), a autonomia é o direito que cada indivíduo possui de definir os desfechos do seu tratamento sem que haja coerção de outrem. Partindo disso, é necessário o conhecimento das mais variadas culturas, como, por exemplo, os princípios religiosos de Testemunhas de Jeová, para que não seja infringido o que é exposto pelo Código de Ética Médica, nos artigos 22, 24 e 31, os quais dispõem que o médico deve explicar os procedimentos, obter consentimento para realizá-los e, por fim, respeitar a vontade do paciente ou dos familiares responsáveis por ele. Além disso, a liberdade religiosa é garantida pela Constituição Brasileira de 1988, na qual se lê, no artigo 5º, inciso VI, “[...] ser inviolável o direito à liberdade de consciência e de crença, devendo ser assegurada o seu livre exercício.” A religião supracitada prega a não utilização de recursos de transfusão sanguínea e seus hemoderivados, sendo tal decisão baseada em seu livro religioso, em que se lê, em Gênesis (9:3-4), que todo animal que se move pode servir de alimento exceto a carne com seu sangue, e também em Levítico (17:10), que todo homem que ingerir qualquer tipo de sangue será eliminado do meio do seu povo (WILLEMAN, 2010, p. 157). Contudo, em determinados casos, conforme rege o Código de Ética Médica, em seu artigo 31, quando há risco iminente de vida para o paciente, o médico pode desrespeitar o direito deste, ou de seu representante legal, de decidir sobre as práticas diagnósticas ou terapêuticas a serem executadas. Também há situações em que mesmo sendo realizada a transfusão, o indivíduo não estará desrespeitando seus princípios religiosos, como ocorre quando este aceita sangue em momentos de debilidade e demonstra posterior arrependimento, e quando lhe é imposto o procedimento de hemotransfusão pelo médico, pois julga-se que ele não desrespeitou a própria consciência e perante a isso não pode ser julgado (WILLEMAN, 2010, p. 158). A partir disso, conclui-se que se deve respeitar a autonomia do paciente, buscando sempre alternativas para o tratamento desde que não haja risco de morte para ele.Palavras-chave: Testemunhas de Jeová. Ética médica. Autonomia. Transfusão sanguínea

Identifying and visualizing variability in object-oriented variability-rich systems

International audienceIn many variability-intensive systems, variability is implemented in code units provided by a host language, such as classes or functions, which do not align well with the domain features. Annotating or creating an orthogonal decomposition of code in terms of features implies extra effort, as well as massive and cumbersome refactoring activities. In this paper, we introduce an approach for identifying and visualizing the variability implementation places within the main decomposition structure of object-oriented code assets in a single variability-rich system. First, we propose to use symmetry, as a common property of some main implementation techniques, such as inheritance or overloading, to identify uniformly these places. We study symmetry in different constructs (e.g., classes), techniques (e.g., subtyping, overloading) and design patterns (e.g., strategy, factory), and we also show how we can use such symmetries to find variation points with variants. We then report on the implementation and application of a toolchain, symfinder, which automatically identifies and visualizes places with symmetry. The publicly available application to several large open-source systems shows that symfinder can help in characterizing code bases that are variability-rich or not, as well as in discerning zones of interest w.r.t. variability

New Element Organic Frameworks Based on Sn, Sb, and Bi, with Permanent Porosity and High Catalytic Activity

We present new element organic frameworks based on Sn, Sb and Bi atoms connected via organic linkers by element-carbon bonds. The open frameworks are characterized by specific surface areas (BET) of up to 445 m² g⁻¹ and a good stability under ambient conditions resulting from a highly hydrophobic inner surface. They show good performance as heterogeneous catalysts in the cyanosylilation of benzaldehyde as a test reaction. Due to their catalytic activity, this class of materials might be able to replace common homogeneous element-organic and often highly toxic catalysts especially in the food industry

Roles for ADAM17 in TNF-R1 Mediated Cell Death and Survival in Human U937 and Jurkat Cells

Signaling via death receptor family members such as TNF-R1 mediates pleiotropic biological outcomes ranging from inflammation and proliferation to cell death. Pro-survival signaling is mediated via TNF-R1 complex I at the cellular plasma membrane. Cell death induction requires complex IIa/b or necrosome formation, which occurs in the cytoplasm. In many cell types, full apoptotic or necroptotic cell death induction requires the internalization of TNF-R1 and receptosome formation to properly relay the signal inside the cell. We interrogated the role of the enzyme A disintegrin and metalloprotease 17 (ADAM17)/TACE (TNF-α converting enzyme) in death receptor signaling in human hematopoietic cells, using pharmacological inhibition and genetic ablation. We show that in U937 and Jurkat cells the absence of ADAM17 does not abrogate, but rather increases TNF mediated cell death. Likewise, cell death triggered via DR3 is enhanced in U937 cells lacking ADAM17. We identified ADAM17 as the key molecule that fine-tunes death receptor signaling. A better understanding of cell fate decisions made via the receptors of the TNF-R1 superfamily may enable us, in the future, to more efficiently treat infectious and inflammatory diseases or cancer

Biosynthesis of Salmonella enterica [NiFe]-hydrogenase-5 : probing the roles of system-specific accessory proteins

A subset of bacterial [NiFe]-hydrogenases have been shown to be capable of activating dihydrogen-catalysis under aerobic conditions; however, it remains relatively unclear how the assembly and activation of these enzymes is carried out in the presence of air. Acquiring this knowledge is important if a generic method for achieving production of O2-resistant [NiFe]-hydrogenases within heterologous hosts is to be developed. Salmonella enterica serovar Typhimurium synthesizes the [NiFe]-hydrogenase-5 (Hyd-5) enzyme under aerobic conditions. As well as structural genes, the Hyd-5 operon also contains several accessory genes that are predicted to be involved in different stages of biosynthesis of the enzyme. In this work, deletions in the hydF, hydG, and hydH genes have been constructed. The hydF gene encodes a protein related to Ralstonia eutropha HoxO, which is known to interact with the small subunit of a [NiFe]-hydrogenase. HydG is predicted to be a fusion of the R. eutropha HoxQ and HoxR proteins, both of which have been implicated in the biosynthesis of an O2-tolerant hydrogenase, and HydH is a homologue of R. eutropha HoxV, which is a scaffold for [NiFe] cofactor assembly. It is shown here that HydG and HydH play essential roles in Hyd-5 biosynthesis. Hyd-5 can be isolated and characterized from a ΔhydF strain, indicating that HydF may not play the same vital role as the orthologous HoxO. This study, therefore, emphasises differences that can be observed when comparing the function of hydrogenase maturases in different biological systems

Hydrogen‐Bond‐Modulated Nucleofugality of SeIII Species to Enable Photoredox‐Catalytic Semipinacol Manifolds

Chemical bond activations mediated by H-bond interactions involving highly electronegative elements such as nitrogen and oxygen are powerful tactics in modern catalysis research. On the contrary, kindred catalytic regimes in which heavier, less electronegative elements such as selenium engage in H-bond interactions to co-activate C−Se σ-bonds under oxidative conditions are elusive. Traditional strategies to enhance the nucleofugality of selenium residues predicate on the oxidative addition of electrophiles onto SeII-centers, which entails the elimination of the resulting SeIV moieties. Catalytic procedures in which SeIV nucleofuges are substituted rather than eliminated are very rare and, so far, not applicable to carbon-carbon bond formations. In this study, we introduce an unprecedented combination of O−H⋅⋅⋅Se H-bond interactions and single electron oxidation to catalytically generate SeIII nucleofuges that allow for the formation of new C−C σ-bonds by means of a type I semipinacol process in high yields and excellent selectivity