Existence and Construction of Vessiot Connections

A rigorous formulation of Vessiot's vector field approach to the analysis of general systems of partial differential equations is provided. It is shown that this approach is equivalent to the formal theory of differential equations and that it can be carried through if, and only if, the given system is involutive. As a by-product, we provide a novel characterisation of transversal integral elements via the contact map

GnRH Binding RNA and DNA Spiegelmers A Novel Approach toward GnRH Antagonism

AbstractMirror-image oligonucleotide ligands (Spiegelmers) that bind to the pharmacologically relevant target gonadotropin-releasing hormone I (GnRH) with high affinity and high specificity have been identified using the Spiegelmer technology. GnRH is a decapeptide that plays an important role in mammalian reproduction and sexual maturation and is associated with several benign and malignant diseases. First, aptamers that bind to D-GnRH with dissociation constants of 50–100 nM were isolated out of RNA and DNA libraries. The respective enantiomers of the DNA and RNA aptamers were synthesized, and their binding to L-GnRH was shown. These Spiegelmers bind to L-GnRH with similar affinity to that of the corresponding aptamers that bind to D-GnRH. We further demonstrated dose-dependent inhibition of GnRH-induced Ca2+ release in Chinese hamster ovary cells that were stably transfected with the human GnRH receptor

E-Commerce- Chancen und Risiken für die Lebensmittelbranche im 21. Jahrhundert

Food Science Summer School der Hochschule f?r Angewandte Wissenschaften (HAW), Hamburg, 20.–21. Juni 2012 Zweit?gige wissenschaftliche Veranstaltungsreihe zum Thema ,,E-Commerce – Chancen und Risiken f?r die Lebensmittelbranche im 21. Jahrhundert‘‘ bringt unter der Leitung von Prof. Dr. Jan Fritsche Spezialisten der Food-Branche und Food Science-Studierende der HAW Hamburg zusammen. Im Rahmen der ersten ,,Food Science Summer School‘‘ haben zwo?lf Referentinnen und Referenten aus Verbraucherorganisationen, der Lebensmittelbranche, der amtlichen Lebensmittel?berwachung und der HAW Hamburg intensiv ?ber die Chancen und Risiken des ,,E-Commerce‘‘ f?r die Lebensmittelbranche diskutiert. Den Auftakt der Vortragsreihe machte ein Redner aus den eigenen Reihen: Prof. Dr. Christoph Wegmann von der Fakult?t Life Sciences gab dem Publikum eine marktorientierte Einf?hrung in die Thematik ,,E-Commerce‘‘. Es folgten weitere Vortr?ge unter anderem von Ingolf Schubert (EDEKA), der ?ber die Transformation eines klassischen Lebensmitteleinzelhändlers in einen online Vollsortiment-Lebensmittelmarkt referierte. Dr. Alexander Decker (Nestl?) beschrieb die unterschiedlichen Herausforderungen bei der Realisierung einer integrierten Kommunikations- und Shop- Plattform hinsichtlich Kundenerwartung, Kommunikation und Prozessen. Der zweite Tag der ,,Food Science Summer School behandelte unter anderem das Thema Lebensmittelsicherheit im Internet. Spezialisten f?r dieses Thema waren Dr. Georg Schreiber und Alexander Krewinkel vom Bundesamt f?r Verbraucherschutz und Lebensmittelsicherheit (BVL) in Berlin. M.Sc. Alexandra Krewinkel, Alumni der HAW Hamburg im Studiengang Food Science, stellte in ihrem Vortrag, Entwicklung IT-basierter Suchstrategien zur Kontrolle des virtuellen Lebensmittelmarkts; die derzeitig bestehenden technischen Herausforderungen für eine effektive Kontrolle des internetbasierten Lebensmittelhandels dar. Lösungsansätze für das Monitoring des Online-Lebensmittelhandels im Rahmen eines interdisziplin?ren Forschungsprojektes stellten die HAW Professoren Dirk Lewandowski, Boris Tolg und Jan Fritsche vor. Auf den folgenden Seiten sind Kurzfassungen verschiedener Vorträge der Veranstaltung nachzulesen

Nuclei of chicken neurons in tissues and three-dimensional cell cultures are organized into distinct radial zones.

We used chicken retinospheroids (RS) to study the nuclear architecture of vertebrate cells in a three-dimensional (3D) cell culture system. The results showed that the different neuronal cell types of RS displayed an extreme form of radial nuclear organization. Chromatin was arranged into distinct radial zones which became already visible after DAPI staining. The distinct zones were enriched in different chromatin modifications and in different types of chromosomes. Active isoforms of RNA polymerase II were depleted in the outermost zone. Also chromocenters and nucleoli were radially aligned in the nuclear interior. The splicing factor SC35 was enriched at the central zone and did not show the typical speckled pattern of distribution. Evaluation of neuronal and non-neuronal chicken tissues showed that the highly ordered form of radial nuclear organization was also present in neuronal chicken tissues. Furthermore, the data revealed that the neuron-specific nuclear organization was remodeled when cells spread on a flat substrate. Monolayer cultures of a chicken cell line did not show this extreme form of radial organization. Rather, such monolayer cultures displayed features of nuclear organization which have been described before for many different types of monolayer cells. The finding that an extreme form radial nuclear organization, which has not been described before, is present in RS and tissues, but not in cells spread on a flat substrate, suggests that it would be important to complement studies on nuclear architecture performed with monolayer cells by studies on 3D cell culture systems and tissues