ABSTRACT
We provide a quantum information description of a proposed five-blade neutron interferometer geometry and show that it is robust against low-frequency mechanical vibrations and dephasing due to the dynamical phase. The extent to which the dynamical phase affects the contrast in a neutron interferometer is experimentally shown. In our model, we consider the coherent evolution of a neutron wavepacket in an interferometer crystal blade and simulate the effect of mechanical vibrations and momentum spread of the neutron through the interferometer. The standard three-blade neutron interferometer is shown to be immune to dynamical phase noise but prone to noise from mechanical vibrations, and the decoherence free subspace four-blade neutron interferometer is shown to be immune to mechanical vibration noise but prone to noise from the dynamical phase. Here, we propose a five-blade neutron interferometer and show that it is immune to both low-frequency mechanical vibration noise and dynamical phase noise.
ABSTRACT
Next to in vitro-cultured autogeneic keratinocytes for the restoration of epidermis, a suitable dermal matrix is a mandatory component of an artificial skin substitute for the permanent covering of full thickness skin defects. In our model a xenogeneic membrane, consisting of processed native collagen and elastin of porcine origin is meant to serve as a template for the formation of a neo-dermis. In order to improve the resistance of this matrix against enzymatical degradation, we cross-linked it by using the carbodiimide 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) together with N-hydroxysuccinimide. Chemical cross-linking by these agents at two different degrees (shrinkage temperatures 63 degrees C and 81 degrees C) had no relevant effect on mechanical features or water-uptake capacity. The time needed for enzymatic digestion was increased by cross-linking. Concerning growth and spreading of fibroblasts and keratinocytes on and within the structure of this membrane, we did not observe a difference between cross-linked and non-cross-linked material (shrinkage temperature 48 degrees C). We therefore expect that cross-linking by EDC is an effective means to control the degradation of the collagen/elastin membranes in vivo without a significant influence on their biocompatibility.
ABSTRACT
In an experimental model in rats, xenogeneic membranes consisting of processed native collagen and elastin were grafted to serve as a template for the formation of a neo-dermis, while in vitro-cultured autogeneic keratinocytes were applied on top of this to restore an epidermis. The process of tissue reconstruction and the digestion of the grafted membrane components were analysed by histological and immunohistochemical methods as well as electron microscopy. Approximately 3 weeks post grafting the membranes were completely vascularised and colonized by different types of cells. After 6 weeks, the collagenous fibres of the graft were mostly replaced by newly formed collagenous texture, whereas elastic membrane components were still present even after 20 weeks. In a second step, in vitro-cultured keratinocytes were applied onto the partially integrated membranes, resulting in an epithelial coverage of approximately 47% of the grafted area after 8-11 days. As early as on day 6 post application, a multilayered, partially differentiated epithelium, together with lymphocytes and Langerhans' cells, could be observed. After 10 days the formation of a basement membrane including anchoring fibrils appeared to be complete. This three-dimensional matrix structure offers a promising scaffold for a tissue engineering strategy to restore skin structure and function. Further experimental studies are in progress to test its applicability to human skin replacement.
