Resonances in Loewner equations

We prove that given a Herglotz vector field on the unit ball of $\mathbb{C}^n$ of the form $H(z,t)=(a_1 z_1,...,a_n z_n)+O(|z|^2)$ with $\Re a_j<0$ for all $j$, its evolution family admits an associated Loewner chain, which is normal if no real resonances occur. Hence the Loewner-Kufarev PDE admits a solution defined for all positive times.Comment: 23 pages, corrected typos, revised argument in Proposition 5.5, result unchange

Loewner equations on complete hyperbolic domains

We prove that, on a complete hyperbolic domain D\subset C^q, any Loewner PDE associated with a Herglotz vector field of the form H(z,t)=A(z)+O(|z|^2), where the eigenvalues of A have strictly negative real part, admits a solution given by a family of univalent mappings (f_t: D\to C^q) such that the union of the images f_t(D) is the whole C^q. If no real resonance occurs among the eigenvalues of A, then the family (e^{At}\circ f_t) is uniformly bounded in a neighborhood of the origin. We also give a generalization of Pommerenke's univalence criterion on complete hyperbolic domains.Comment: 19 pages, revised exposition, improved results, added reference

Vascular implants – new aspects for in situ tissue engineering

Conventional synthetic vascular grafts require ongoing anticoagulation, and autologous venous grafts are often not available in elderly patients. This review highlights the development of bioartificial vessels replacing brain-dead donor- or animal-deriving vessels with ongoing immune reactivity. The vision for such bio-hybrids exists in a combination of biodegradable scaffolds and seeding with immune-neutral cells, and here different cells sources such as autologous progenitor cells or stem cells are relevant. This kind of in situ tissue engineering depends on a suitable bioreactor system with elaborate monitoring systems, three-dimensional (3D) visualization and a potential of cell conditioning into the direction of the targeted vascular cell phenotype. Necessary bioreactor tools for dynamic and pulsatile cultivation are described. In addition, a concept for design of vasa vasorum is outlined, that is needed for sustainable nutrition of the wall structure in large caliber vessels. For scaffold design and cell adhesion additives, different materials and technologies are discussed. 3D printing is introduced as a relatively new field with promising prospects, for example, to create complex geometries or micro-structured surfaces for optimal cell adhesion and ingrowth in a standardized and custom designed procedure. Summarizing, a bio-hybrid vascular prosthesis from a controlled biotechnological process is thus coming more and more into view. It has the potential to withstand strict approval requirements applied for advanced therapy medicinal products

Recent advances in melt electro writing for tissue engineering for 3D printing of microporous scaffolds for tissue engineering

Melt electro writing (MEW) is a high-resolution 3D printing technique that combines elements of electro-hydrodynamic fiber attraction and melts extrusion. The ability to precisely deposit micro- to nanometer strands of biocompatible polymers in a layer-by-layer fashion makes MEW a promising scaffold fabrication method for all kinds of tissue engineering applications. This review describes possibilities to optimize multi-parametric MEW processes for precise fiber deposition over multiple layers and prevent printing defects. Printing protocols for nonlinear scaffolds structures, concrete MEW scaffold pore geometries and printable biocompatible materials for MEW are introduced. The review discusses approaches to combining MEW with other fabrication techniques with the purpose to generate advanced scaffolds structures. The outlined MEW printer modifications enable customizable collector shapes or sacrificial materials for non-planar fiber deposition and nozzle adjustments allow redesigned fiber properties for specific applications. Altogether, MEW opens a new chapter of scaffold design by 3D printing

RESQME and Stand-Alone Simulation on a Workstation

RC 16037 (#71232) The Research Queueing Package Modeling Environment (RESQME) provides a graphical environment for constructing and solving extended queueing network models ofmanufacturing systems, for plotting graphs of results and for viewdng animations of models. The modeling environment can be run entirely on a workstation or optionally can execute large simulations on a host system using cooperative processing. In this paper we give a brief introduction to RESQME and to the RESQ modeling elements. We demonstrate how to use the package by constructing a simple model of part of a manufacturing line and solve this model to produce charts of performance measures and an animation which shows how the jobs flow through the system. By having the simulation available for use on the workstation and cooperatively on the host, RESQME provides a unique tool for understanding the performance of manufacturing systems. A user can do most of the model debugging locally on the workstation and make short püot runs to get a feeling for the amount of resources necessary to make more realistic experiments on the • host. Then long runs which investigate large parts ofthe parameter space can be done cooperatively on the host. Whether the model is solved on the workstation or on the hosMhe graphics environment provides the same user interface to all of the underlying files. The processor where the model is solved is transparent to the user. In aU cases, the user has easy access to plots ofresults and to the animation ofthe model diagra

Determinación de Salmonelosis y Shigelosis en manipuladores de alimentos que laboran en el área geográfica de influencia de la Unidad de Salud San Carlos municipio y departamento de San Miguel en el período de abril a octubre de 2003

Se estudiaron 53 muestras fecales de manipuladores de alimentos que laboran en los 21 establecimientos (comedores, pupuserías, bar y restaurante, comedor y pupuseria, venta de panes, panaderías, molinos) ubicados en el área geográfica de influencia de la Unidad de Salud San Carlos del Municipio y Departamento de San Miguel. Durante el período de abril a octubre de 2003. Con los objetivos generales de conocer a través del coprocultivo la presencia de Salmonella y Shigella en manipuladores de alimentos que laboran en el área geográfica de influencia de la Unidad de Salud San Carlos, proporcionar ayuda a dichas personas por medio de análisis de muestras que evalúen su estado de salud; y con los objetivos específicos de determinar especies de Salmonella y Shigella a través de pruebas bioquímicas, determinar especies de Salmonella y Shigella a través de sueros tipiadores y señalar el número de casos de Salmonelosis y Shigelosis obtenidos en manipuladores de alimentos. El tipo de investigación que se realizó es de laboratorio ya que se realizaron pruebas, procedimientos y técnicas de laboratorio, de campo porque los investigadores se dirigieron al sitio de estudio manteniendo un contacto con la comunidad proporcionando información y toma de muestras para el estudio, bibliográfico porque para fundamentar la investigación se recopilaron datos a través de libros, textos, revistas, tesis e internet. A través de estos elementos se concretiza la investigación obteniéndose los resultados, los cuales sirvieron para la elaboración de tablas y gráficos; estableciéndose lo siguiente: El 60.38% de las bacterias que se aislaron corresponden a Escherichia coli, el 16.98% pertenece a Citrobacter freundii y Citrobacter intermedium, el otro porcentaje le corresponde a Citrobacter diversus que es el 3.77% y Proteus mirabilis con un 1.89%. Se puede considerar que el 100% de las bacterias aisladas no tienen importancia clínica, ya que todas forman parte de la flora normal intestina

On Uniqueness of Boundary Blow-up Solutions of a Class of Nonlinear Elliptic Equations

We study boundary blow-up solutions of semilinear elliptic equations $Lu=u_+^p$ with $p>1$, or $Lu=e^{au}$ with $a>0$, where $L$ is a second order elliptic operator with measurable coefficients. Several uniqueness theorems and an existence theorem are obtained.Comment: To appear in Comm. Partial Differential Equations; 10 page

Gefäße drucken und kultivieren : Auf dem Weg zum Gefäßimplantat aus der Retorte!

Künstliche Implantate sind für Patient*innen immer mit Risiken verbunden. Es kann etwa zu einer Abstoßung kommen, außerdem müssen oft dauerhaft Medikamente eingenommen werden. Wissenschaftler*innen der AG Blume am Institut für Technische Chemie (TCI) arbeiten daher an der Entwicklung einer patientenindividuellen Gefäßprothese als Medizinprodukt, welche langfristig als Ersatz erkrankter oder beschädigter Blutgefäße fungieren kann

Supersymmetric version of a hydrodynamic system in Riemann invariants and its solutions

In this paper, a supersymmetric extension of a system of hydrodynamic type equations involving Riemann invariants is formulated in terms of a superspace and superfield formalism. The symmetry properties of both the classical and supersymmetric versions of this hydrodynamical model are analyzed through the use of group-theoretical methods applied to partial differential equations involving both bosonic and fermionic variables. More specifically, we compute the Lie superalgebras of both models and perform classifications of their respective subalgebras. A systematic use of the subalgebra structures allow us to construct several classes of invariant solutions, including travelling waves, centered waves and solutions involving monomials, exponentials and radicals.Comment: 30 page