Formation of Porous Silicon Filter Structures with Different Properties on Small Areas

Porous silicon (PS) layer systems have a broad range of possible applications. An advantage is the good control of the refractive index and the etch rate of the layers by the applied current density and the time respectively. For micro-optical devices you need patterned PS. For some optical devices it is not sufficient to have only one filter but it is necessary to form filters with different properties on a small area. We applied a method (M. Frank, U.B. Schallenberg, N. Kaiser, and W. Buß, in Conference on Miniaturized Systems with Microoptics and Micromechanics, edited by M.E. Moamedi, L.J. Hornbeck, and K.S.J. Pister (SPIE, San Jose, 1997), SPIE Proceedings Series 3008, p. 265) to PS which fits this goal by the following steps: fabrication of the desired reflectors below each other and partial removal of upper reflectors with reactive ion etching (RIE). The technological aspects of patterning PS after the fabrication are an important topic of this work. Problems are discussed in detail and solutions are given

Electrical Control of the Reflectance of Porous Silicon Layers

In this paper we demonstrate the filling of porous silicon (PS) layers with liquid crystals (LC’s) in order to control the reflectance electrically. The preparation of PS and the choice of the right group of LC’s will be presented. Especially an oxidation of PS is necessary so that the methods and parameters of oxidation will also be discussed. As a first result the increasing and decreasing of the thickness oscillations in the reflectance as a function of the applied voltage can be observed

A systematic review of CD14 and toll-like receptors in relation to asthma in Caucasian children

The aetiology of childhood asthma is complex. An early dysfunction in immunological development of the innate immune system in combination environmental factors possibly triggers asthma. CD14 and toll-like important components of the innate immune system. The aim of this review was to obtain a better insight into the relation between CD14 and toll-like receptors and childhood asthma in Caucasians. We searched EMBASE for relevant articles. In total, 44 articles were included. The the selected studies was independently assessed by the first two authors the Newcastle-Ottawa quality assessment scale. Toll-like receptor 2, receptor 6, toll-like receptor 9, and toll-like receptor 10 appear to association with childhood asthma in Caucasians. The evidence for a CD14 with childhood asthma is limited. In conclusion, there is no evidence yet for a role of CD14 and toll-like receptors in relation to asthma. Future studies should include haplotype analysis and take factors into account to further clarify the role of CD14 and toll-like on childhood asthma