Showing papers by "Fraunhofer Society published in 2003"

The production of recombinant pharmaceutical proteins in plants.

Abstract: Imagine a world in which any protein, either naturally occurring or designed by man, could be produced safely, inexpensively and in almost unlimited quantities using only simple nutrients, water and sunlight. This could one day become reality as we learn to harness the power of plants for the production of recombinant proteins on an agricultural scale. Molecular farming in plants has already proven to be a successful way of producing a range of technical proteins. The first plant-derived recombinant pharmaceutical proteins are now approaching commercial approval, and many more are expected to follow.

Photovoltaic materials, history, status and outlook

Abstract: This paper reviews the history, the present status and possible future developments of photovoltaic (PV) materials for terrestrial applications. After a brief history and introduction of the photovoltaic effect theoretical requirements for the optimal performance of materials for pn-junction solar cells are discussed. Most important are efficiency, long-term stability and, not to be neglected, lowest possible cost. Today the market is dominated by crystalline silicon in its multicrystalline and monocrystalline form. The physical and technical limitations of this material are discussed. Although crystalline silicon is not the optimal material from a solid state physics point of view it dominates the market and will continue to do this for the next 5–10 years. Because of its importance a considerable part of this review deals with materials aspects of crystalline silicon. For reasons of cost only multicrystalline silicon and monocrystalline Czochralski (Cz) crystals are used in practical cells. Light induced instability in this Cz-material has recently been investigated and ways to eliminate this effect have been devised. For future large scale production of crystalline silicon solar cells development of a special solar grade silicon appears necessary. Ribbon growth is a possibility to avoid the costly sawing process. A very vivid R&D area is thin-film crystalline silicon (about 5–30 μm active layer thickness) which would avoid the crystal growing and sawing processes. The problems arising for this material are: assuring adequate light absorption, assuring good crystal quality and purity of the films, and finding a substrate that fulfills all requirements. Three approaches have emerged: high-temperature, low-temperature and transfer technique. Genuine thin-film materials are characterized by a direct band structure which gives them very high light absorption. Therefore, these materials have a thickness of only one micron or less. The oldest such material is amorphous silicon which is the second most important material today. It is mainly used in consumer products but is on the verge to also penetrate the power market. Other strong contenders are chalcogenides like copper indium diselenide (CIS) and cadmium telluride. The interest has expanded from CuInSe 2 , to CuGaSe 2 , CuInS 2 and their multinary alloys Cu(In,Ga)(S,Se) 2 . The two deposition techniques are either separate deposition of the components followed by annealing on one hand or coevaporation. Laboratory efficiencies for small area devices are approaching 19% and large area modules have reached 12%. Pilot production of CIS-modules has started in the US and Germany. Cadmium telluride solar cells also offer great promise. They have only slightly lower efficiency and are also at the start of production. In the future other materials and concepts can be expected to come into play. Some of these are: dye sensitized cells, organic solar cells and various concentrating systems including III/V-tandem cells. Theoretical materials that have not yet been realized are Auger generation material and intermediate metallic band material.

Plasma treatment of polymers for surface and adhesion improvement

Abstract: Different plasma treatments in a rf discharge of Ar, He, or N 2 are used to etch, cross-link, and activate polymers like PC, PP, EPDM, PE, PS, PET and PMMA. Due to the numerous ways a plasma interacts with the polymer surface, the gas type and the plasma conditions must be adjusted on the polymer type to minimize degradation and aging effects. Wetting and friction properties of polymers can be improved by a simple plasma treatment, demonstrated on PC and EPDM, respectively. However, the deposition of ultra-thin layers by plasma enables the adjustment of wetting properties, using siloxane-based or fluorocarbon films, and further reduction of the friction coefficient, applying siloxane or a-C:H coatings. Nevertheless, the adhesion of plasma-deposited coatings should be regarded, which can be enhanced by depositing a graded layer.

H.264/AVC in wireless environments

Abstract: Video transmission in wireless environments is a challenging task calling for high-compression efficiency as well as a network friendly design. Both have been major goals of the H.264/AVC standardization effort addressing "conversational" (i.e., video telephony) and "nonconversational" (i.e., storage, broadcast, or streaming) applications. The video compression performance of the H.264/AVC video coding layer typically provides a significant improvement. The network-friendly design goal of H.264/AVC is addressed via the network abstraction layer that has been developed to transport the coded video data over any existing and future networks including wireless systems. The main objective of this paper is to provide an overview over the tools which are likely to be used in wireless environments and discusses the most challenging application, wireless conversational services in greater detail. Appropriate justifications for the application of different tools based on experimental results are presented.

Fatigue life models for SnAgCu and SnPb solder joints evaluated by experiments and simulation

Abstract: In recent years, many solder fatigue models have been developed to predict the fatigue life of solder joints under thermal cycle conditions. While a variety of life prediction models have been proposed for near eutectic SnPb(Ag)-solder joints in the literature, not enough work has been reported in extending these models to lead-free soldered assemblies. The development of lie prediction models requires a deep insight into failure modes, constitutive models for the themnomechanical behavior of solders and an experimental reliability database. This is needed for the correlation of experimentally determined cycles-to-failure to simulation results by fmiteelement analysis. This paper describes in detail the life-prediction models of SnPh(Ag) and SnAgCu solder joints for thermal cycle conditions. To obtain reliable FEM input and to verify simulation results, a variety of material testing and experimental fatigue data is necessary. The accuracy of lieprediction tools has also become critically important, as the designs need to he evaluated and improved with a high degree of reliability, not through relative comparison but by providing absolute numbers. This work deals with the effect of different solder interconnect alloys (Sn59Pb40Agl and Sn95.5Ag3.8Cu0.7) and the effect of different package types (PBGAs, CSPs, Flip Chip on FR-4 with and without underfill) on the fatigue life. Different temperature cycling conditions are applied.

Endocrine disruptors in the environment (IUPAC Technical Report)

Abstract: Many chemical substances of natural or anthropogenic origin are suspected or known to be endocrine disruptors, which can influence the endocrine system of life. This observation has led to increased interest on the part of the public and the media, as well as to a steep rise of research activities in the scientific community. New papers and results are presented so fast that it is impossible to give a complete review of this emerging research field. Therefore, this paper tries to give insight into some topics of the great scope of endocrine disruptors in the environment. To get a general idea of the biochemical and biological background, some parts of the endocrine systems of mammalians and nonmammalians are explained. The sections that follow describe important mechanisms of endocrine disruption such as interactions with hormone receptors. Test strategies for anthropogenic chemicals on various organisms are critically reviewed with respect to their problems and gaps concerning endocrine disruptors. The main emphasis of the paper is on the chemical substances suspected or known to be endocrine disruptors. To get a better comprehension of their behavior in the environment, physicochemical data such as water solubility or K o w , as well as information about their use and/or function are reviewed and compared. The main routes of exposure for most chemicals are shortly described, and data about concentrations in the environment (soil/sediment, water) are detailed.

Transaction cost economics

Abstract: In the debate on no-regret potentials, transaction costs are a rather controversial issue On the one hand, the controversy concerns the level of transaction costs related to energy saving measures Existing cost-benefit analyses for energy saving measures are often criticised for being incomplete because, allegedly, they would not fully account for transaction costs Depending on the level of transaction costs, this negligence is more or less severe Some studies, e g Sutherland (1991), hold that transaction costs are so high that they challenge favourable results of quantitative cost-benefit analyses and explain why energy-efficient technologies are not adopted Other studies implicitly assume transactions costs to be zero (e g Lovins, Lovins 1991; Landwehr et al 1996) As pointed out, e g by Golove and Eto (1996, p 24) this aspect of the debate suggests a need to empirically quantify transaction costs and integrate them in the cost-benefit assessment of the measures considered

Effects of laser sintering processing parameters on the microstructure and densification of iron powder

Abstract: The densification behavior and the attendant microstructural features of iron powder processed by direct laser sintering were investigated. The effects of processing parameters such as laser power, scan rate, scan line spacing, thickness of layer, scanning geometry and sintering atmosphere were studied. A specific energy input (ψ) was defined using the “energy conservation” rule to explore the effects of the processing condition on the density and the attendant microstructure of laser sintered iron. It was found that the sintered density increased sharply with increasing the specific energy input until a critical energy input had been reached (ψ∼0.2 kJ mm−3). The microstructure consists of large pores (>0.5 mm) and elongated ferrite grains parallel to the building direction. The increase in the sintered density was followed with further increasing the specific energy, but at slower rate. Intensifying the energy input over 0.8 kJ mm−3 leads to the formation of horizontally elongated pores while the sintered density remains almost constant. The inter-agglomerates are fully dense and consist of elongated ferrite grains which are oriented parallel to the building direction. The iron powder was used as a model material so the outcomes are generic and can be applied to other material systems with congruent melting point or systems which melting/solidification approach is the mechanism feasible for the rapid bonding of metal powders in direct laser sintering.

Monitoring manual control of electric lighting and blinds

Abstract: This paper reviews, validates and extends present knowledge of the degree and kind of manual control strategies of blinds and electric lighting systems that are used in private and two-person offices. A new monitoring setup was applied from March to December 2000 in 10 daylit offices in Germany that featured manually operated electric lighting and automatically controlled external venetian blinds with manual override. The data shows that individuals consistently followed the same control strategy for their electric lighting and blinds. Groups of individuals tended to activate their electric lighting according to Hunt’s probability function, although there was a large spread between individual control levels. All subjects used their blinds to avoid direct sunlight above 50 W/m2, and incoming solar gains above 50 klux (~450 W/m2). They also were more willing to accept automatic blind opening than closing.

From forecasting to foresight processes—new participative foresight activities in Germany

Abstract: The definitions of forecasting vary to a certain extent, but they all have the view into the future in common. The future is unknown, but the broad, general directions can be guessed at and reasonably dealt with. Foresight goes further than forecasting, including aspects of networking and the preparation of decisions concerning the future. This is one reason why, in the 1990s, when foresight focused attention on a national scale in many countries, the wording also changed from forecasting to foresight. Foresight not only looks into the future by using all instruments of futures research, but includes utilizing implementations for the present. What does a result of a futures study mean for the present? Foresight is not planning, but foresight results provide ‘information’ about the future and are therefore one step in the planning and preparation of decisions. In this paper, some of the differences are described in a straightforward manner and demonstrated in the light of the German foresight process ‘Futur’. Copyright © 2003 John Wiley & Sons, Ltd.

Transparent Sintered Corundum with High Hardness and Strength

Abstract: Commercial corundum powder and a liquid-shaping approach are used for manufacturing complex hollow components and large flat windows of sintered and hot isostatically pressed Al2O3 ceramics having grain sizes of 0.4–0.6 μm at relative densities of >99.9%. High macrohardness (HV10 = 20–21 GPa) and four-point bending strength (600–700 MPa; 750–900 MPa in three-point bending) are associated with a real in-line transmission of 55%–65% through polished plates. The submicrometer microstructure and the optical properties can be retained for use at >1100°C using dopants that shift the sintering temperature to high values without additional grain growth.

Transgene integration, organization and interaction in plants

Abstract: It has been appreciated for many years that the structure of a transgene locus can have a major influence on the level and stability of transgene expression. Until recently, however, it has been common practice to discard plant lines with poor or unstable expression levels in favor of those with practical uses. In the last few years, an increasing number of experiments have been carried out with the primary aim of characterizing transgene loci and studying the fundamental links between locus structure and expression. Cereals have been at the forefront of this research because molecular, genetic and cytogenetic analysis can be carried out in parallel to examine transgene loci in detail. This review discusses what is known about the structure and organization of transgene loci in cereals, both at the molecular and cytogenetic levels. In the latter case, important links are beginning to be revealed between higher order locus organization, nuclear architecture, chromatin structure and transgene expression.

Spectral response measurements of monolithic GaInP/Ga(In)As/Ge triple-junction solar cells : measurement artifacts and their explanation

Abstract: Procedures for measuring the spectral response of multi-junction cells in general require variation of the bias spectrum and voltage biasing. It is shown that a refined procedure including optimization of bias spectrum and voltage is necessary to minimize a measurement artifact, which appears if the subcell under test has non-ideal properties, such as a low shunt resistance or a low reverse breakdown voltage. This measurement artifact is often observed on measuring the spectral response of the Ge bottom cell of GaInP/Ga(In)As/Ge triple-junction cells. The main aspect of the measurement artifact is that the response of another subcell is simultaneously measured, while at the same time the signal of the Ge subcell is too low. Additionally, the shape of the spectral response curve is influenced under certain measurement conditions. In this paper the measurement artifact is thoroughly discussed by measurement results and simulation. Based on this analysis, a detailed procedure for the spectral response measurement of multi-junction cells is developed, specially designed to minimize such measurement artifacts. Copyright © 2003 John Wiley & Sons, Ltd.

Molecular farming of recombinant antibodies in plants.

Abstract: Antibodies represent a large proportion of therapeutic drugs currently in development. In most cases, they are produced in mammalian cell lines or transgenic animals because these have been shown to fold and assemble the proteins correctly and generate authentic glycosylation patterns. However, such expression systems are expensive, difficult to scale up and there are safety concerns due to potential contamination with pathogenic organisms or oncogenic DNA sequences. Plants represent an inexpensive, efficient and safe alternative for the production of recombinant antibodies. Research over the last 10 years has shown that plants can produce a variety of functional antibodies and there is now intense interest in scaling up production to commercial levels. In this review, we discuss the advantages of plants over traditional expression systems, describe how antibody expression in plants is achieved and optimized and then consider the practical issues concerning large-scale molecular farming in plants. The first plant-produced therapeutic antibodies are already in clinical trials, and, given the economic benefits of this production system, we are likely to see many more recombinant antibodies produced in this manner in the future.

Linking Technology Areas to Industrial Sectors

Abstract: Technological innovations are one of the key factors in explaining economic competitiveness of advanced countries. Therefore it is important to monitor technological development of areas, countries and regions in a systematic way to support economic analysis and decision making. It is, however, impossible to describe the technological development by a single indicator encompassing all aspects and stages of innovation. Rather, it is necessary to establish a network of related indicators reflecting different aspects of innovation. At the same time to examine the relationship between technology and economic performance it is crucial to link technological indicators with those related to economic performance. At the international level, most economic indicators such as turnover, investment, employment, productivity, value added, R&D expenditure etc. are classified by industrial sectors, for instance, according to the NACE or ISIC schemes. In contrast, some of the most frequently used indicators for technology are based on patent statistics, classified according to the International Patent Classification (IPC).5 However, the IPC is based on technological categories and cannot be directly translated into industrial sectors. One approach for solving this problem is to establish a reliable concordance between technology and industry classifications.

Expressivity versus efficiency of graph kernels

Abstract: Recently, kernel methods have become a popular tool for machine learning and data mining. As most ‘real-world’ data is structured, research in kernel methods has begun investigating kernels for various kinds of structured data. One of the most widely used tools for modeling structured data are graphs. In this paper we study the trade-off between expressivity and efficiency of graph kernels. First, we motivate the need for this discussion by showing that fully general graph kernels can not even be approximated efficiently. We also discuss generalizations of graph kernels defined in literature and show that they are either not positive definite or not very useful. Finally, we propose a new graph kernel based on subtree patterns. We argue that while a little more computationally expensive, this kernel is more expressive than kernels based on walks.

Tubular graphite cones.

Abstract: We report the synthesis of tubular graphite cones using a chemical vapor deposition method. The cones have nanometer-sized tips, micrometer-sized roots, and hollow interiors with a diameter ranging from about 2 to several tens of nanometers. The cones are composed of cylindrical graphite sheets; a continuous shortening of the graphite layers from the interior to the exterior makes them cone-shaped. All of the tubular graphite cones have a faceted morphology. The constituent graphite sheets have identical chiralities of a zigzag type across the entire diameter, imparting structural control to tubular-based carbon structures. The tubular graphite cones have potential for use as tips for scanning probe microscopy, but with greater rigidity and easier mounting than currently used carbon nanotubes.

Self-assembled microarrays of attoliter molecular vessels.

Abstract: High-d. microarrays of attoliter vol. elements can be created within minutes in a parallel and effortless manner by using self-assembly of nanometer-size components based on biol. recognition. These ultrasmall vols. allow localization of single mols., screening for (bio)chem. properties, and assessing the performance of confined chem. reactions. [on SciFinder (R)]

Presenting route instructions on mobile devices

Abstract: In this paper, we evaluate several means of presenting route instructions to a mobile user. Starting from an abstract language-independent description of a route segment, we show how to generate various presentations for a mobile device ranging from spoken instructions to 3D visualizations. We then examine the relationship between the quality of positional information, available resources and the different types of presentations. The paper concludes with guidelines that help to determine which presentation to choose for a given situation