Influence of Conductive Additives and Binder on the Impedance of Lithium-Ion Battery Electrodes: Effect of Morphology

Most cathode materials for lithium ion batteries exhibit a low electronic conductivity. Hence, a significant amount of conductive graphitic additives are introduced during electrode production. The mechanical stability and electronic connection of the electrode is enhanced by a mixed phase formed by the carbon and binder materials. However, this mixed phase, the carbon binder domain CBD , hinders the transport of lithium ions through the electrolyte pore network. Thus, reducing the performance at higher currents. In this work we combine microstructure resolved simulations with impedance measurements on symmetrical cells to identify the influence of the CBD distribution. Microstructures of NMC622 electrodes are obtained through synchrotron X ray tomography. Resolving the CBD using tomography techniques is challenging. Therefore, three different CBD distributions are incorporated via a structure generator. We present results of microstructure resolved impedance spectroscopy and lithiation simulations, which reproduce the experimental results of impedance spectroscopy and galvanostatic lithiation measurements, thus, providing a link between the spatial CBD distribution, electrode impedance, and half cell performance. The results demonstrate the significance of the CBD distribution and enable predictive simulations for battery design. The accumulation of CBD at contact points between particles is identified as the most likely configuration in the electrodes under consideratio

Identification of a novel α(1→6) mannopyranosyltransferase MptB from Corynebacterium glutamicum by deletion of a conserved gene, NCgl1505, affords a lipomannan- and lipoarabinomannan-deficient mutant

Mycobacterium tuberculosis and Corynebacterium glutamicum share a similar cell wall structure and orthologous enzymes involved in cell wall assembly. Herein, we have studied C. glutamicum NCgl1505, the orthologue of putative glycosyltransferases Rv1459c from M. tuberculosis and MSMEG3120 from Mycobacterium smegmatis. Deletion of NCgl1505 resulted in the absence of lipomannan (Cg-LM-A), lipoarabinomannan (Cg-LAM) and a multi-mannosylated polymer (Cg-LM-B) based on a 1,2-di-O-C16/C18:1-(α-D-glucopyranosyluronic acid)-(1→3)-glycerol (GlcAGroAc2) anchor, while syntheses of triacylated-phosphatidyl-myo-inositol dimannoside (Ac1PIM2) and Man1GlcAGroAc2 were still abundant in whole cells. Cell-free incubation of C. glutamicum membranes with GDP-[14C]Man established that C. glutamicum synthesized a novel α(1→6)-linked linear form of Cg-LM-A and Cg-LM-B from Ac1PIM2 and Man1GlcAGroAc2 respectively. Furthermore, deletion of NCgl1505 also led to the absence of in vitro synthesized linear Cg-LM-A and Cg-LM-B, demonstrating that NCgl1505 was involved in core α(1→6) mannan biosynthesis of Cg-LM-A and Cg-LM-B, extending Ac1PI[14C]M2 and [14C]Man1GlcAGroAc2 primers respectively. Use of the acceptor α-D-Manp-(1→6)-α-D-Manp-O-C8 in an in vitro cell-free assay confirmed NCgl1505 as an α(1→6) mannopyranosyltransferase, now termed MptB. While Rv1459c and MSMEG3120 demonstrated similar in vitroα(1→6) mannopyranosyltransferase activity, deletion of the Rv1459c homologue in M. smegmatis did not result in loss of mycobacterial LM/LAM, indicating a functional redundancy for this enzyme in mycobacteria

Lipoarabinomannan biosynthesis in Corynebacterineae: the interplay of two α(1→2)-mannopyranosyltransferases MptC and MptD in mannan branching

Lipomannan (LM) and lipoarabinomannan (LAM) are key Corynebacterineae glycoconjugates that are integral components of the mycobacterial cell wall, and are potent immunomodulators during infection. LAM is a complex heteropolysaccharide synthesized by an array of essential glycosyltransferase family C (GT-C) members, which represent potential drug targets. Herein, we have identified and characterized two open reading frames from Corynebacterium glutamicum that encode for putative GT-Cs. Deletion of NCgl2100 and NCgl2097 in C. glutamicum demonstrated their role in the biosynthesis of the branching α(1→2)-Manp residues found in LM and LAM. In addition, utilizing a chemically defined nonasaccharide acceptor, azidoethyl 6-O-benzyl-α-D-mannopyranosyl-(1→6)-[α-D-mannopyranosyl-(1→6)]7-D-mannopyranoside, and the glycosyl donor C50-polyprenol-phosphate-[14C]-mannose with membranes prepared from different C. glutamicum mutant strains, we have shown that both NCgl2100 and NCgl2097 encode for novel α(1→2)-mannopyranosyltransferases, which we have termed MptC and MptD respectively. Complementation studies and in vitro assays also identified Rv2181 as a homologue of Cg-MptC in Mycobacterium tuberculosis. Finally, we investigated the ability of LM and LAM from C. glutamicum, and C. glutamicumΔmptC and C. glutamicumΔmptD mutants, to activate Toll-like receptor 2. Overall, our study enhances our understanding of complex lipoglycan biosynthesis in Corynebacterineae and sheds further light on the structural and functional relationship of these classes of polysaccharides

The Mycobacterium Tuberculosis FAS-II Dehydratases and Methyltransferases Define the Specificity of the Mycolic Acid Elongation Complexes

BACKGROUND: The human pathogen Mycobacterium tuberculosis (Mtb) has the originality of possessing a multifunctional mega-enzyme FAS-I (Fatty Acid Synthase-I), together with a multi-protein FAS-II system, to carry out the biosynthesis of common and of specific long chain fatty acids: the mycolic acids (MA). MA are the main constituents of the external mycomembrane that represents a tight permeability barrier involved in the pathogenicity of Mtb. The MA biosynthesis pathway is essential and contains targets for efficient antibiotics. We have demonstrated previously that proteins of FAS-II interact specifically to form specialized and interconnected complexes. This finding suggested that the organization of FAS-II resemble to the architecture of multifunctional mega-enzyme like the mammalian mFAS-I, which is devoted to the fatty acid biosynthesis. PRINCIPAL FINDINGS: Based on conventional and reliable studies using yeast-two hybrid, yeast-three-hybrid and in vitro Co-immunoprecipitation, we completed here the analysis of the composition and architecture of the interactome between the known components of the Mtb FAS-II complexes. We showed that the recently identified dehydratases HadAB and HadBC are part of the FAS-II elongation complexes and may represent a specific link between the core of FAS-II and the condensing enzymes of the system. By testing four additional methyltransferases involved in the biosynthesis of mycolic acids, we demonstrated that they display specific interactions with each type of complexes suggesting their coordinated action during MA elongation. SIGNIFICANCE: These results provide a global update of the architecture and organization of a FAS-II system. The FAS-II system of Mtb is organized in specialized interconnected complexes and the specificity of each elongation complex is given by preferential interactions between condensing enzymes and dehydratase heterodimers. This study will probably allow defining essential and specific interactions that correspond to promising targets for Mtb FAS-II inhibitors

Mycobacterium tuberculosis Rv3802c Encodes a Phospholipase/Thioesterase and Is Inhibited by the Antimycobacterial Agent Tetrahydrolipstatin

The cell wall of M. tuberculosis is central to its success as a pathogen. Mycolic acids are key components of this cell wall. The genes involved in joining the α and mero mycolates are located in a cluster, beginning with Rv3799c and extending at least until Rv3804c. The role of each enzyme encoded by these five genes is fairly well understood, except for Rv3802c. Rv3802 is one of seven putative cutinases encoded by the genome of M. tuberculosis. In phytopathogens, cutinases hydrolyze the waxy layer of plants, cutin. In a strictly mammalian pathogen, such as M. tuberculosis, it is likely that these proteins perform a different function. Of the seven, we chose to focus on Rv3802c because of its location in a mycolic acid synthesis gene cluster, its putative essentiality, its ubiquitous presence in actinomycetes, and its conservation in the minimal genome of Mycobacterium leprae. We expressed Rv3802 in Escherichia coli and purified the enzymatically active form. We probed its activities and inhibitors characterizing those relevant to its possible role in mycolic acid biosynthesis. In addition to its reported phospholipase A activity, Rv3802 has significant thioesterase activity, and it is inhibited by tetrahydrolipstatin (THL). THL is a described anti-tuberculous compound with an unknown mechanism, but it reportedly targets cell wall synthesis. Taken together, these data circumstantially support a role for Rv3802 in mycolic acid synthesis and, as the cell wall is integral to M. tuberculosis pathogenesis, identification of a novel cell wall enzyme and its inhibition has therapeutic and diagnostic implications

Making sense of big data in health research: Towards an EU action plan.

Medicine and healthcare are undergoing profound changes. Whole-genome sequencing and high-resolution imaging technologies are key drivers of this rapid and crucial transformation. Technological innovation combined with automation and miniaturization has triggered an explosion in data production that will soon reach exabyte proportions. How are we going to deal with this exponential increase in data production? The potential of "big data" for improving health is enormous but, at the same time, we face a wide range of challenges to overcome urgently. Europe is very proud of its cultural diversity; however, exploitation of the data made available through advances in genomic medicine, imaging, and a wide range of mobile health applications or connected devices is hampered by numerous historical, technical, legal, and political barriers. European health systems and databases are diverse and fragmented. There is a lack of harmonization of data formats, processing, analysis, and data transfer, which leads to incompatibilities and lost opportunities. Legal frameworks for data sharing are evolving. Clinicians, researchers, and citizens need improved methods, tools, and training to generate, analyze, and query data effectively. Addressing these barriers will contribute to creating the European Single Market for health, which will improve health and healthcare for all Europeans

Identification and characterization of novel hedgehog signaling pathway inhibitors and their cellular targets

As a major developmental pathway, Hedgehog (Hh) signaling is required for segment polarity in Drosophila and limb pattering in vertebrates. Since its discovery 40 years ago, several studies have identified various pathway components and helped to elucidate the underlying mechanisms of signal transduction. Nevertheless, some regulatory steps during pathway induction are not yet fully understood. Similar to other developmental pathways like Wnt, TGFβ or Notch signaling, also Hh signaling plays a central role in cancer, e.g. medulloblastoma and basal cell carcinoma. Due to the open questions concerning pathway mechanisms and the relevance in some forms of cancer, novel modulators of Hh signaling are in high demand. Following a high-throughput screen for inhibition of Purmorphamine-induced osteogenesis, six inhibitors of Hedgehog signaling were characterized in this thesis. All compounds inhibited GLI-responsive reporter gene expression and suppressed the expression of Hh target genes. Two compounds, a withanolide A- and a pyrazolo-imidazole derivative bind to the heptahelical bundle of SMO, a membrane protein and central transducer of Hh signaling activity also known as the most druggable target of the Hh signaling pathway. The pyrazolo-imidazole derivative, termed Smoothib, impairs ciliary entry of SMO and most likely adopts a binding mode similar to that of SANT-1, a SMO antagonist that is effective against resistant SMO mutants. Four further compounds, quinoline-, indole-, azepinone- and thienopyrimidine derivatives, did not bind to the cyclopamine binding site of SMO. Screening of a kinase panel revealed that the thienopyrimidine derivative, termed Pipinib, selectively inhibits phosphatidylinositol 4-kinase IIIβ (PI4KB) in an ATP-competitive manner. This lipid kinase is required for production of phosphatidylinositol-4-phosphate (PI4P) and necessary for proper function and integrity of the Golgi apparatus as well as membrane trafficking and protein transport from the trans-Golgi network to the plasma membrane. Cellular levels of PI4P were reduced upon treatment with Pipinib, suggesting that PI4KB is inhibited by the compound in cells. PI4KB was validated as a positive regulator of Hh signaling via chemical and genetic depletion. PI4KB depletion sensitizes cells towards treatment with Pipinib, suggesting that PI4KB mediates Hh inhibition of Pipinib. Mode of action studies revealed that Pipinib impairs ciliary trafficking of PI4KB and that PI4KA inhibition only leads to minor reduction of Hh signaling. In combination with an already published role of PI4P in SMO activation, the results of this thesis lead to the conclusion that PI4KB is a major PI4-kinase source of PI4P that is required for SMO activation and transduction of Hh signaling activity.Als ein bedeutender entwicklungsbiologischer Signalweg ist der Hedgehog (Hh)-Signalweg verantwortlich für die Segmentpolarität in Drosophila und die Extremitätenentwicklung in Vertebraten. Seit seiner Entdeckung vor 40 Jahren wurden zahlreiche Mitglieder der zugehörigen Signalkaskade identifiziert. Nichtsdestotrotz wurden einige Schritte des Signalwegs bisher noch nicht komplett aufgeklärt. In Analogie zu anderen entwicklungsbiologischen Signalwegen spielt auch die Hh-Signaltransduktion eine zentrale Rolle in gewissen Krebserkrankungen, z.B. beim Medulloblastom und Basalzellkarzinom. Aufgrund der offenen Fragen bezüglich der Signaltransduktion und der Relevanz für die Krebsentstehung werden neue Hh-Modulatoren dringend gesucht. Ausgehend von einem Hochdurchsatz-Screening für Inhibitoren der Purmorphamin-induzierten Osteogenese wurden im Rahmen dieser Arbeit sechs Inhibitoren des Hh-Signalwegs charakterisiert. Alle Substanzen inhibierten GLI-vermittelte Reportergen- und Hh Zielgenexpression. Ein Withanolid A- und ein Pyrazolo-Imidazol-Derivat binden an das heptahelikale Bündel von SMO, ein Membranprotein, das für die Signalweiterleitung verantwortlich ist und als am besten zu inhibierendes Zielprotein im Signalweg gilt. Das Pyrazolo-Imidazol-Derivat, genannt Smoothib, beeinträchtigt den ziliären Eintritt von SMO und bindet SMO in einem Modus, der dem bekannten SMO-Inhibitor SANT-1 gleicht, welcher Resistenzen gegenüber SMO Antagonisten überwinden kann. Vier weitere Substanzen, ein Chinolin-, ein Indol-, ein Azepinon- und ein Thienopyrimidin-Derivat binden nicht an die Cyclopamin-Bindungsstelle von SMO. Die Bestimmung der Inhibition von Kinasen ergab, dass das Thienopyrimidin-Derivat, genannt Pipinib, die Phosphatidylinositol 4-Kinase IIIβ (PI4KB) selektiv und ATP-kompetitiv inhibiert. Diese Lipidkinase ist wichtig für die korrekte Funktion und Integrität des Golgi-Apparats sowie den Membrantransport und den Transport von Proteinen vom trans-Golgi-Netzwerk zur Plasmamembran. Die Behandlung mit Pipinib führte zur Reduktion der zellulären PI4P-Pegel, was zur Annahme führte, dass PI4KB auch in Zellen durch Pipinib inhibiert wird. PI4KB wurde mittels chemischer und genetischer Depletion als positiver Regulator des Hh Signalwegs validiert. Depletion von PI4KB führte zu einer Sensibilisierung der Zellen gegenüber Pipinib. Dies spricht dafür, dass PI4KB die inhibitorische Wirkung von Pipinib auf den Hh Signalweg vermittelt. Die Substanz beeinträchtigt die ziliäre Lokalisation von SMO. Die Inhibition von PI4KA hingegen, führt nur zu einer geringen Inhibition des Hh-Signalwegs. In Kombination mit einer bereits veröffentlichten Rolle von PI4P in der Aktivierung von SMO, führen die Ergebnisse dieser Arbeit zu dem Schluss, dass PI4KB eine wichtige Quelle für PI4P darstellt, welches für die Aktivierung von SMO und die Weiterleitung des Hh-Signals entscheidend ist

Equestrian sport sponsoring : opportunities and risks for medium-sized businesses using the company RidersDeal GmbH as an example

Die vorliegende Arbeit befasst sich mit der Analyse der Chancen und Risiken von Investitionen in Reitsport-Sponsoring durch mittelständische Unternehmen, wie die RidersDeal GmbH. Das Hauptziel ist herauszufinden, welche Möglichkeiten das Reitsport-Sponsoring für mittelständische Unternehmen bietet, wie der Sponsoring-Prozess am sinnvollsten aufgebaut werden kann und wie Reitsport-Sponsoring auf Rezipienten wirkt. Im Anschluss werden die Punkte in Bezug auf die RidersDeal GmbH analysiert, um Handlungsempfehlungen auszusprechen, durch welche das Unternehmen einen möglichst großen Nutzen aus dem Reitsport-Sponsoring ziehen kann. Zur Erreichung dieses Ziels wurde im Rahmen der Primärforschung eine Online-Befragung durchgeführt. Weiterhin wurde vorhandenes Datenmaterial in Form von Literatur und Internetquellen analysiert

Investigation of the antiadhesive properties of biomimetic titanium nanostructures in fluidic flow

Within this work, the bacterial adhesion on biomimetic titanium nanostructures is investigated in fluidic flow. The motile, gram-negative bacteria strain Escherichia coli was used for the experiments and was incubated on nanostructured titanium, polished titanium and on the wings of the dragonfly Neuorbasis kaupi. After incubation period different flow velocities have been applied and the reduction of adhered bacteria was determined via fluorescence microscopy. Results show that nanostructured titanium surfaces have the ability to reduce the bacterial contamination as it is for the dragon fly wings used in this study. This behavior can also be predicted by analyzing the bearing area of the nanotopography which describes the actual part of the topography which is in contact to the bacteria