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Free standing metal screens have long been used as band pass filters in the infrared (IR) wavelength region. One adjusts the screens’ periodicity constant, its opening-to-periodicity aspect ratio and its thickness to achieve desired infrared transmission properties. Here we concentrate on thick screens in the near IR wavelength region (1–2 μm). In addition to experiments and simulations we have considered the role of screen imperfection on its transmission characteristics. Uneven surfaces, inclined and sometimes rough walls of the screen and waveguide channels may be the result of thick-film lithography which is used in the process for screen manufacturing. Understanding these effects is crucial to applications of these filters in the entire IR region.

With a view to meeting the requirements of high resolution microelectromechanical system applications, we studied high resolution (submicron scale) and high aspect ratio pattern fabrication through x-ray lithography. As a critical part of the x-ray lithography, an x-ray mask should have the properties of high resolution and being a thick absorber. To decrease the scattering effect, a 100 keV e-beam lithography system was used for the fabrication of the high resolution x-ray mask. 3 ?m thick PMMA (polymethylmethacrylate) resist was patterned and 2 ?m thick gold was electroplated onto the patterned resist to form the x-ray mask. Scanning electron microscopy analysis showed that the sidewall and pattern uniformity were sufficient and that the proximity effect did not play a significant role for the selected test patterns. 6 ?m thick PMMA resist was exposed by the x-ray mask; the experimental results proved the feasibility of reproducing submicron features. 0.5 ?m nested patterns with an aspect ratio of 12 were fabricated by this approach.

Thick capacitive meshes of nickel on substrates of thickness 25 lm have been produced by electroplating into a photoresist mould. The Micro-Stripes program by Flomerics has been used for the interpretation of the experimentally measured far infrared spectrum. The measured reflection resonance mode and the transmission wave guide mode agree well with the analytical predictions. 2003 Elsevier B.V. All rights reserved.

Environmental pollutants can influence the expression of immunoregulatory molecules and, in this way, promote allergies. The local synthesis of proinflammatory chemokines is an important aspect in the development of allergic airway inflammation. We have characterized the influence of pyrene, a polycyclic aromatic hydrocarbon (PAH) contained, for example, in diesel exhaust particles (DEP), on transcription and secretion of the chemokines interleukin-8 (IL-8) and eotaxin. Reporter genes under control of the respective promoters were tested in the human cell lines A549 and HeLa, mRNA production was assayed in A549 cells and protein production was measured by ELISA in cell supernatants from primary human fibroblasts. Pyrene content of cell supernatants was measured by analytical HPLC. Promoter activity, mRNA production and protein expression of IL-8 were increased by pyrene. The activating effect in reporter gene studies was abolished by mutating either an NF-κB or an AP-1 binding site in the IL-8 promoter. In contrast, pyrene showed no effect on transcription from the eotaxin promoter, despite the important role of this chemokine in asthma. Our data show that pyrene has specific effects on chemokine synthesis, which are not restricted to mediators primarily associated with atopic diseases. Pyrene also affected cells not derived from lung tissue, which suggests a broader immunoregulatory influence for this pollutant.

This paper presents a technology study for fabrication of ''V''-shaped silver nanoantennas with critical dimensions below 20nm. Two process sequences are investigated based on electron beam lithography, a lift off process using the positive resist polymethylmethacrylate (PMMA) and a novel process based on argon ion etching using the negative resist hydrogen silsesquioxane (HSQ). The fabrication processes are monitored by SEM investigations. Attenuated total reflection (ATR) measurements demonstrate the optical activity of the nanoantennas and allow the validation of the technology routes.

The eosinophil chemotactic beta-chemokine MCP-4 is assumed to be involved in the accumulation of eosinophils characteristic for eosinophilic inflammatory diseases. We here describe the genomic organisation (3 exons of 138, 115 and 578 bp, 2 introns of 867 and 437 bp and 1.4 kb of regulatory sequences from the immediate 5' upstream region), sequence (genomic and transcribed) and mRNA expression of the human MCP-4 gene in dermal fibroblasts. Among the promoter elements potentially regulating MCP-4 gene expression and/or mediating the effects of anti-inflammatory drugs we identified consensus sequences known to interact with nuclear factors like NF-IL6, AP-2, a NF-kappaB like consensus sequence, gamma-interferon- response and YY-1 elements as well as glucocorticoid response elements. Like MCP-3, MCP-4 mRNA expression in dermal fibroblasts is upregulated by TNF-alpha, IL-1alpha, IFN-gamma or IL-4 and differs from RANTES and eotaxin mRNA expression in its response to IFN-gamma and/or IL-4.

Eotaxin is an eosinophil specific β-chemokine assumed to be involved in eosinophilic inflammatory diseases such as atopic dermatitis, allergic rhinitis, asthma and parasitic infections. Its expression is stimulus- and cell- specific. We here describe the genomic organisation (3 exons of 132, 112 and 542 bp and 2 introns of 1211 and 378 bp) and sequence including 3 kb of DNA from the immediate 5′ upstream region of the human eotaxin gene. Among the regulatory promoter elements potentially regulating eotaxin gene expression and/or mediating the effects of anti-inflammatory drugs we identified consensus sequences known to interact with nuclear factors like NF-IL6, AP-1, a NF-κ-B like consensus sequence and γ-interferon- as well as glucocorticoid response elements.

We investigate fluctuations in the magnetoconductance (measured at T o 50 mK) of noble-metal nanowires in a mesoscopic two-lead configuration, with lengths 500 and 1000 nm and widths w between 45 and 360 nm. We determine the dependence of the correlation field Bc on the angle u between the direction of the magnetic field and the long axis of the wires. u is changed at low T continuously from 90± (usual geometry) to 0±. We present a calculation taking into account the 3D diffusive motion of the conduction electrons describing the angular dependence of Bc. We compare this Bcsud dependence with conductance fluctuations observed while sweeping u at constant magnetic field. [S0031-9007(97)03042-1]

Polymer optical waveguide devices will play a key role in several rapidly developing areas such as optical networks, biophotonic and fluidic applications. We have developed a technology which enables the increase of the refractive index of methylmethacrylate based polymers by deep ultra violet (DUV) radiation. The modification of the dielectric properties of polymers by DUV is a useful technique for the realization of photonic integrated optical circuits. The technique presented here has several advantages with respect to common methods because only a single polymer layer is used, which serves as the substrate and waveguide as well and no further etching or development step is required. This method can not only be applied to planar polymer substrates but also to preembossed substrates. This enables the fabrication of ridge waveguide based devices by hot embossing. Nickel stampers with feature heights of about 15-20 μm and aspect ratios usually between 2:1 and 3:1 can be utilized for replication without major effort. Nickel stampers are not only used to replicate optical waveguides, but are also used to realize fluidic channels in the range of several microns. UV modification of methylmethacrylate polymers additionally leads to a new surface chemistry affecting the selective absorption of proteins and the adhesion of living cells in vitro. The bi-functionality of the modified polymer chips supporting waveguides and cell anchorage capabilities at the same time provides the opportunity to monitor protein adsorption, cell attachment and spreading processes by evanescent-field techniques.

Microcomponents can be manufactured not only by silicon technologies, bu talso by many other technologies, e.g. precision engineering, laser ablation, microelectrodischarge, RIE and by the LIGA process. In this paper, the state of the art of the LIGA technology and its industrial applications are presented, which have been developed in recent years at the Forschungszentrum Karlsruhe. Related technologies are described as well. This includes the use of a sacrificial layer and an alternative process technology for the fabrication of mold inserts using conventional UV-lithography with the negative resist SU-8. With respect to applications of the LIGA technology, a brief introduction to their specific fabrication processes and their functionality is presented. These are microspectrometers, optical fiber connectors, cycloid gear systems, optical heterodyne receivers and micro-mechanical gyroscopes.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

DNQ-Novolak based photoresists are applied in many fields of microstructure technology. A common feature of such resist structures (>10 micrometer) described in the literature is a concave profile with the narrowest part at approximately 2/3 of the resist height. By newly including effects of residual solvent concentration, the simulation program accurately describes characteristic resist profiles for AZ4562 between 10 and 100 micrometer resist thickness. The program calculates the vertical distribution of the residual solvent concentration by modeling the evaporation during prebake as a three step process: diffusion of solvent within the resist film to the surface, a transfer to the ambient air described by a phase equilibrium and a transport away from the surface described by convection. Required parameters of the model have been obtained by fitting measured evaporation rates as function of time with the prebake temperature as a parameter to calculated ones. Resist exposure is simulated in vertical and one lateral dimension using the well known Dill's theory with ABC-parameters for DNQ resists. The development process is described by percolation theory where the residual solvent concentration increases the percolation parameter and therefore the local development rate. This paper describes details of the mathematical models used, demonstrates good agreement between experimentally observed profiles and simulated ones and shows that the influence of process parameters such as prebake temperature or time on resist profiles can be accurately simulated.

In this paper, a prototype of 2 mm-diameter micro-cycloid gear system fabricated by the multi-exposure LIGA technique is presented. The entire gear system consists of a casing and three vertically stacked disks and gears. Each part is composed of three different levels. The first level, 40 micrometers high, was fabricated by UV-lithography, and the second as well as the third level, 195 micrometers and 250 micrometers high respectively, were processed by aligned deep X-ray lithography (DXL). The alignment error between two DXL- processed layers was measured, and the results have turned out to be within +/- 5 micrometers range. As a result of the height control process by the mechanical surface machining, the deviation of structural height has been maintained within +/- 3 micrometers range for the UV-lithography-processed structures, and +/- 10 micrometers for the DXL-processed structures. Further the tests of gear assembly were implemented with 125 micrometers -diameter glass fiber, by using a die-bonding machine with vacuum gripper under stereo- microscope. Finally the dynamic tests of the gear system were successfully conducted with the mechanical torque input by an electrical motor. A proper rotational speed reduction was observed in the operational input range of 3 to 1500 rpm with the designed gear ratio of 18.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We describe the fabrication of planar metallic nanostructures with lateral dimensions down to about 80 nm and thicknesses varying from 15 to 50 nm. We use a lift‐off process with a polymethylmethacerylate bilayer resist on silicon substrate and an electron beam writer system for microfabrication. The noble‐metal layers are deposited by thermal evaporation. The geometries are point contacts, rings, and wires in two‐lead configuration. We discuss measurements of the magnetoconductance at very low temperatures and in magnetic fields up to 4 T in dependence of the width of the samples. Here the electron transport is in the diffusive regime and the width dependence of the universal conductance fluctuations is investigated.