The efficacy of USDA approved antimicrobials was evaluated in reducing Salmonella and Campylobacter on ground chicken frames and chicken breast fillets. Chicken frames dip treated with peracetic acid (PAA), lauric arginate (LAE), cetylpyridinium chloride (CPC) and acidified lactic acid (ALA) reduced Salmonella and Campylobacter counts in ground chicken frames without affecting meat pH and color. PAA and LAE reduced Salmonella by 0.9 log on d0 whereas on d1, PAA and CPC reduced by 1.4 and 0.9 log CFU/g respectively. PAA, ALA, propionic acid and LAE significantly reduced Campylobacter by 0.7, 1.0, 1.3, and 1.2 log CFU/g, respectively. On chicken breast fillets, 30 s application of PAA (0.04% and 0.07% pH 6.5) reduced loosely attached Salmonella by 0.5 and 0.8 log CFU/ml, respectively. ALA, octanoic acid and PAA reduced loosely attached Campylobacter by 1 log while all treatments except propionic acid were effective against strongly attached cells on chicken breast fillets.

Studien handlar om utveckling av ett flexibelt klokopplingssystem tillsammans med SwePart Transmissioner AB. Principen bygger på att en hylsa med utvändiga splines belastas i inkopplingsförloppet. Hylsan skapar en axiell rörelse som sedan absorberas av fjädrar vilket utgör flexibiliteten i klokopplingen. Studien besvarar frågorna om vilka samband som finns mellan olika faktorer i systemet och hur dessa påverkar dimensioneringen samt vilka modifieringar som måste göras för att uppfylla funktionskraven. Författarna har gjort ett flertal simuleringar på inkopplingsförloppet med programmet MSC Adams för att generera data som krävs för att kunna dimensionera systemet. Resultatet av varje simuleringsförsök utgörs av plottar med storheter som vridmoment, fjäderkraft och förskjutningar. En analys är sedan gjord för att finna den bästa dimensioneringen av ett antal kandidater av kopplingen samt flera olika förslag på idéer för vidare studier. Det finns flera olika samband mellan de uppsatta faktorerna och en dimensionering rekommenderas.

Die antiinflammatorischen, proproliferativen und antiapoptotischen Eigenschaften mesenchymaler Stromazellen (MSC) stellen einen innovativen Therapieansatz zur Förderung der Leberregeneration nach einer Leberteilresektion dar. Nach der bereits erfolgreichen Etablierung im murinen Kleintiermodell galt es nun die Erkenntnisse auf ein dem humanen Organismus näherstehendes Großtiermodell zu übertragen. Die hier vorliegende Arbeit soll dabei die Wirkung mesenchymaler Stromazellen im Rahmen einer ausgedehnten Leberteilresektion auf die Funktion und Morphologie des Restlebergewebes im porcinen Großtiermodell untersuchen. Insgesamt wurden 12 Landrasseschweine einer 70 %igen Leberteilresektion unterzogen. Weitere drei Schweine wurden ebenfalls dem perioperativen Procedere unterzogen, erhielten jedoch keine Leberteilresektion (sogenannte Sham-Gruppe). Jeweils vier Schweine erhielten im Rahmen der Resektion entweder zentralvenös (MSC_ZV-Gruppe) oder portalvenös (MSC_PV-Gruppe) applizierte porcine bone marrow-MSC. Die restlichen vier Tiere erhielten mit PBS lediglich die Trägersubstanz der MSC (PBS-Gruppe). 24 h nach Resektion wurden alle Tiere euthanasiert. Während des Versuches erfolgten zu definierten Zeitpunkten die Erhebung laborchemischer Parameter, die Ermittlung der Indocyaningrün (ICG)-Clearance (LiMON®-Test) und die Entnahme von Leberbiopsien. Dabei zeigten sich signifikante Unterschiede zwischen den MSC-Gruppen und der PBS-Gruppe. Die Auswertung der laborchemischen Parameter erbrachte postoperativ für die MSC-Gruppen signifikante Vorteile für den Verlauf der Transaminasen, des Serumammoniaks, der GGT, der LDL, der freien Fettsäuren im Serum, der aPTT, der INR und des CRP. Betrachtet man die Messung der Plasmaverschwinderate des ICG ergaben sich signifikant höhere Clearance-Raten für die mit MSC behandelten Tiere im Vergleich zur PBS-Gruppe. Sowohl die zentral- als auch die portalvenöse Injektion der MSC ließen sich als sichere Applikationswege der MSC etablieren. Die histologischen Untersuchungen mittels HE- und Sudan III-Färbung sowie die immunhistochemischen Färbungen detektierten eine geringere Lipidakkumulation, einen höheren Anteil der Zell-Zell-Kontaktproteine E-Cadherin und ZO-1 sowie einen geringeren Anteil an Thrombospondin-1 (Suppressor der Leberregeneration) in den mit MSC behandelten Tieren verglichen mit der PBS-Gruppe. Die Zusammenschau der Befunde spricht für eine durch MSC induzierte Verbesserung der postoperativen Leberfunktion nach ausgedehnter Leberteilresektion. Mechanistisch könnte dabei die Unterstützung des Erhalts der hepatischen Mikroarchitektur und die Verminderung des Thrombospondin-1 eine Rolle spielen. Letzteres gilt als negativer Prädiktor des Outcomes nach ausgedehnter Leberresektion. Somit stellt die Applikation mesenchymaler Stromazellen eine innovative therapeutische Option zum Erhalt der Leberfunktion nach einer ausgedehnten Leberteilresektion dar.

Falls among the elderly are a major source of injury, often leading to serious fractures, hospitalization, and death. Osteoporosis (OP) is a global problem intimately related with these fractures, characterized by reduced bone mass, increased bone fragility. There exists a high failure rate in the translation of treatments to osteoporotic populations. Mesenchymal stromal cell (MSC) transplantation as a therapeutic strategy for OP has not yet been examined in clinical trials. This may be attributed to the mixed findings of pre-clinical studies aimed at determining the efficacy of MSC therapy towards bone regeneration in OP. The most common animal model of OP is ovariectomy (OVX) that simulates post-menopausal estrogen loss. A plethora of bone regeneration studies have used OVX models with 12-16 weeks post-OVX periods and have generally reported positive results from a variety of treatment modalities, including MSC therapy. However, the use of the minimum post-OVX period may not be appropriate to reflect the global changes in regenerative potential of OP patients. In our research group's previous study, MSC were isolated from a minimum 60 week post-OVX rat model, representing a severe case of OP. The MSC isolated from these animals are a unique cell population that we expect may better represent the outcomes of autologous cell therapies for the older patient population in the clinic. In the present study, adipose and bone marrow derived MSC from OVX and age-matched animals were evaluated for their osteogenic and adipogenic differentiation potentials in culture through passage 10. Results from this study suggest that bone marrow derived-MSC maintain their phenotype and functionality more effectively than adipose derived-MSC in OP. Further investigations used regenerative medicine approaches for cell expansion on keratin protein coated microcarriers in static culture. Hair-derived keratin biomaterials have demonstrated their utility as carriers of biologics and drugs for tissue engineering. An optimal microcarrier was selected that demonstrated superior retention of the protein coating through electrostatic interactions and high cell viability. Finally, the integration of cell-microcarriers into a perfusion bioreactor system was explored. Preliminary results demonstrated the feasibility of MSC growth and differentiation on microcarrier based packed beds. Moreover, AD-MSC from OP rats were unresponsive to both inductive media and shear stress related osteogenic cues. These results highlight the complexity and challenges associated with the MSC regenerative strategy. / Doctor of Philosophy / Osteoporosis is a skeletal disease that results in reduced bone mass, increased bone fragility and fracture risk. Osteoporotic patients who experience falls suffer serious fractures, hospitalization, and poor bone healing. Several different therapies have been developed for the treatment of osteoporosis, though many are unable to translate from the bench to the clinical population. A popular treatment being investigated is the application of mesenchymal stromal cells (MSC) for fracture repair and the reversal of osteoporotic bone losses. However, cells isolated from aged and osteoporotic patients have been shown to have deficient bone forming properties. Nevertheless, animal models of osteoporosis applying this treatment report amelioration of bone loss. This work seeks to examine a more clinically relevant rat model of osteoporosis. Typical osteoporosis models use an ovariectomy procedure to simulate post-menopausal bone loss on relatively young animals and conduct short-term studies. These studies may not accurately reflect the global regenerative changes in osteoporosis patients or the impaired MSC properties. Adipose and bone marrow derived MSC from a long term ovariectomy model were investigated for their regenerative potentials. MSC growth and bone forming potential was evaluated on keratin protein coated microcarriers in both static and perfusion cultures. Results from this study suggest that bone marrow derived MSC maintain their phenotype and functionality more effectively than adipose derived MSC in osteoporosis. Further preliminary results demonstrated the feasibility of MSC growth and differentiation on microcarrier based packed beds. These results highlight the complexity and challenges associated with the MSC regenerative strategy.

In the last years some results for the Laplacian on manifolds have been shown to hold also for the graph Laplacian, e.g. Courant's nodal domain theorem or Cheeger's inequality. Friedman (Some geometric aspects of graphs and their eigenfunctions, Duke Math. J. 69 (3), pp. 487-525, 1993) described the idea of a ``graph with boundary". With this concept it is possible to formulate Dirichlet and Neumann eigenvalue problems. Friedman also conjectured another ``classical" result for manifolds, the Faber-Krahn theorem, for regular bounded trees with boundary. The Faber-Krahn theorem states that among all bounded domains $D \subset R^n$ with fixed volume, a ball has lowest first Dirichlet eigenvalue. In this paper we show such a result for regular trees by using a rearrangement technique. We give restrictive conditions for trees with boundary where the first Dirichlet eigenvalue is minimized for a given "volume". Amazingly Friedman's conjecture is false, i.e. in general these trees are not ``balls". But we will show that these are similar to ``balls". (author's abstract) / Series: Preprint Series / Department of Applied Statistics and Data Processing

In this paper, optimal control problems for semilinear parabolic equations with distributed and boundary controls are considered. Pointwise constraints on the control and on the state are given. Main emphasis is laid on the discussion of second order sufficient optimality conditions. Sufficiency for local optimality is verified under different assumptions imposed on the dimension of the domain and on the smoothness of the given data.

We consider a class of control problems governed by a linear parabolic initial-boundary value problem with linear-quadratic objective and pointwise constraints on the control. The control system contains different types of perturbations. They appear in the linear part of the objective functional, in the right hand side of the equation, in its boundary condition, and in the initial value. Making use of parabolic regularity in the whole scale of $L^p$ the known Lipschitz stability in the $L^2$-norm is improved to the supremum-norm.

In this paper we deal with aspects of characterizing the ill-posedn ess of nonlinear inverse problems based on the discussion of specific examples. In particular, a parameter identification problem to a second order differential equation and its ill-posed linear components are under consideration. A new approach to the classification ofill-posedness degrees for multiplication operators completes the paper.

The paper is dedicated to the modeling and the simulation of random processes and fields. Using the concept and the theory of weakly correlated functions a consistent representation of sufficiently smooth random processes will be derived. Special applications will be given with respect to the simulation of road surfaces in vehicle dynamics and to the confirmation of theoretical results with respect to the zeros of random polynomials.

The paper presents a method for generating curved surfaces of 3D finite element meshes by mesh refinement starting with a very coarse grid. This is useful for parallel implementations where the finest meshes should be computed and not read from large files. The paper deals with simple geometries as sphere, cylinder, cone. But the method may be extended to more complicated geometries. (with 45 figures)