To advance the comprehension of complex biological processes occurring in crop plants (e.g. for improvement of growth or yield) it is of high interest to reconstruct and analyse detailed metabolic ...models. Therefore, we established a pipeline combining software tools for (1) storage of metabolic pathway data and reconstruction of crop plant metabolic models, (2) simulation and analysis of stoichiometric and kinetic models and (3) visualisation of data generated with these models. The applicability of the approach is demonstrated by a case study of cereal seed metabolism.
The Photo Injector Test facility at DESY Zeuthen (PITZ) was built to develop electron sources for the TESLA Test Facility Free Electron Laser and future linear colliders. The main goal is to study ...the production of minimum transverse emittance beams with short bunch length at medium charge (∼1nC). The facility includes a 1.5 cell L-band cavity with coaxial RF coupler, a solenoid for space charge compensation, a laser capable to generate long pulse trains, an UHV photo cathode exchange system, and different diagnostics tools. Besides an overview of the facility, its main components and their commissioning, this contribution will concentrate on the first measurements at PITZ with photoelectrons. This will include measurements of the transverse and longitudinal laser profile, charge and quantum efficiency, momentum and momentum spread, transverse electron beam profiles at different locations and first results on transverse emittance.
The B cell receptor for antigen (BCR) is a complex of membrane immunoglobulin (mIg) and at least two other proteins, Ig alpha (mb-1) and Ig beta (B29). This complex promotes surface expression of the ...BCR and acts to transduce an activation signal. We have used a system of mu heavy chain constructs transfected into murine B cell lines to probe structure-function relationships in the BCR complex. One mutant mu chain, in which two polar transmembrane residues (Tyr587, Ser588) are replaced with valine, fails to associate with Ig alpha and Ig beta and is incapable of transducing signals as a result of mIg cross-linking. This mutant is expressed on the surface at high levels when transfected into a plasmacytoma line that lacks Ig alpha, whereas wild-type mu is retained in this cell line in the endoplasmic reticulum. Pulse-chase and immunoprecipitation analyses indicate that the mutant is more rapidly released from calnexin than the wild-type mu. Further, transfection of Ig alpha into this Ig alpha-negative cell line allows release of the mu chain from calnexin and surface expression of the BCR. These results identify the transmembrane residues of mu heavy chain that control binding to calnexin and Ig alpha, and suggest that calnexin-dependent intracellular retention is an important control mechanism for expression of the BCR complex.
The steady increase of air traffic and the operation of aircraft in almost all environmental conditions demand for advanced sensor concepts for safe and efficient flight service. Furthermore the ...bird's perspective on the Earth allows manifold use of airborne imaging for civilian and military Earth observation. Passive microwave remote sensing is an attractive tool for exploring our environment, offering benefits from optical or infrared frequencies like simple interpretation of images, and those of microwaves like penetration through many obstacles for enhanced vision. Microwave radiometry is a measurement technique based on sampling the naturally generated microwave emission of matter having certain thermal energy content, i.e. a temperature being larger than the absolute zero. Hence, the operation can be executed covert due to the absence of a transmitter, and a radiometric sensor generates no additional electronic pollution, being of importance for avoiding radio frequency interference with other devices and avoiding burden on the anyway tight resources in available frequency bands. Modern microwave technology, in parallel to advanced imaging concepts, offers furthermore real-time operation and compact low-weight sensor design, both being main drivers in sensor construction for airborne vehicles. The paper addresses fundamental relations for two-dimensional imaging in various applications. Basic imaging approaches are outlined and discussed with respect to performance and expense. Various imaging examples of different applications are shown and discussed.
To generate a fast and robust 3-D visualization of the operation site during minimal invasive surgery.
Light fields are used to model and visualize the 3-D operation site during minimal invasive ...surgery. An endoscope positioning robot provides the position and orientation of the endoscope. The a priori un-known transformation from the endoscope plug to the endoscope tip (hand-eye transformation) can either be determined by a three-step algorithm, which includes measuring the endoscope length by hand or by using an automatic hand-eye calibration algorithm. Both methods are described in this paper and their respective computation times and accuracies are compared.
Light fields were generated during real operations and in the laboratory. The comparison of the two methods to determine the unknown hand-eye transformation was done in the laboratory. The results which are being presented in this paper are: rendered images from the generated light fields, the calculated extrinsic camera parameters and their accuracies with respect to the applied hand-eye calibration method, and computation times.
Using an endoscope positioning robot and knowing the hand-eye transformation, the fast and robust generation of light fields for minimal invasive surgery is possible.
Since 1998, the DESY photoinjectors at FLASH and PITZ routinely use high quantum efficiency (QE) photocathodes produced at LASA (INFN-Milano). To further understand the photocathode behavior during ...beam operation, photocathode QE measurements have been performed at different operating conditions in both photoinjectors. The analysis of these measurements will be used to improve the photocathode preparation procedures and deepen our understanding of the photocathode properties. An important goal is to further increase their lifetime and to preserve a high beam quality during the operation in the RF gun of the photoinjector.
Many countries face the problem of land mines and unexploded ordnance contaminated land sections which present a significant risk to the civilian population. The detection and subsequent clearance of ...these explosive hazardous substances is therefore extremely important and necessary. Ground penetrating radar (GPR) is a suitable tool and is considered as a complementing sensor since nearly two decades. However, most GPRs operate in very close distance to ground in a rather punctual method of operation. In contrast, synthetic aperture radar (SAR) is a technique allowing fast and laminar stand-off investigation of an area. In this paper the final radar hardware setup and first railway based measurements are described.
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