| 1. |
- Weidemann, O., et al.
(author)
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Influence of surface oxides on hydrogen-sensitive Pd : GaN Schottky diodes
- 2003
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In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 83:4, s. 773-775
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Journal article (peer-reviewed)abstract
- Influence of surface oxides on hydrogen-sensitive Pd:GaN Schottky diodes was studied. Ex-situ fabricated devices show a sensitivity towards molecular hydrogen, which is about 50 times higher than for in situ deposited diodes. In situ deposited Pd Schottky contacts reveal lower barrier heights and drastically higher reverse currents.
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| 2. |
- Papaspiropoulos, Giorgos, et al.
(author)
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Aerosol elemental concentrations in the tropopause region from intercontinental flights with the Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container (CARIBIC) platform
- 2002
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In: Journal of Geophysical Research: Atmospheres. - 2169-897X. ; 107:D23
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Journal article (peer-reviewed)abstract
- This study with the Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container (CARIBIC) platform investigates the aerosol elemental concentrations at 9-11 km altitude in the northern hemisphere. Measurements from 31 intercontinental flights over a 2-year period between Germany and Sri Lanka/Maldives in the Indian Ocean are presented. Aerosol samples were collected with an impaction technique and were analyzed for the concentration of 18 elements using particle-induced X-ray emission (PIXE). Additional measurements of particle number concentrations, ozone and carbon monoxide concentrations, and meteorological modeling were included in the interpretation of the aerosol elemental concentrations. Particulate sulphur was found to be by far the most abundant element. Its upper tropospheric concentration increased, on average, by a factor of 2 from the tropics to midlatitudes, with another factor 2 higher concentrations in the lowermost stratosphere over midlatitudes. Correlation patterns and source profiles suggest contributions from crustal sources and biomass burning, but not from meteor ablation. Coinciding latitudinal gradients in particulate sulphur concentrations and emissions suggest that fossil fuel combustion is an important source of the aerosol in the upper troposphere and lowermost stratosphere. The measurements indicate aerosol transport along isentropic surfaces across the tropopause into the lowermost stratosphere. As a result of the prolonged residence time, ageing via oxidation of sulphur dioxide in the lowermost stratosphere was found to be a likely high-altitude, strong source that, along with downward transport of stratospheric air, could explain the vertical gradient of particulate sulphur mass concentration around the extratropical tropopause.
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| 3. |
- van Kuilenburg, André B P, et al.
(author)
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Novel disease-causing mutations in the dihydropyrimidine dehydrogenase gene interpreted by analysis of the three-dimensional protein structure
- 2002
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In: Biochemical Journal. - : Portland Press Ltd.. - 0264-6021 .- 1470-8728. ; 364:Pt 1, s. 157-163
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Journal article (peer-reviewed)abstract
- Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disease characterized by thymine-uraciluria in homozygous deficient patients. Cancer patients with a partial deficiency of DPD are at risk of developing severe life-threatening toxicities after the administration of 5-fluorouracil. Thus, identification of novel disease-causing mutations is of the utmost importance to allow screening of patients at risk. In eight patients presenting with a complete DPD deficiency, a considerable variation in the clinical presentation was noted. Whereas motor retardation was observed in all patients, no patients presented with convulsive disorders. In this group of patients, nine novel mutations were identified including one deletion of two nucleotides [1039-1042delTG] and eight missense mutations. Analysis of the crystal structure of pig DPD suggested that five out of eight amino acid exchanges present in these patients with a complete DPD deficiency, Pro86Leu, Ser201Arg, Ser492Leu, Asp949Val and His978Arg, interfered directly or indirectly with cofactor binding or electron transport. Furthermore, the mutations Ile560Ser and Tyr211Cys most likely affected the structural integrity of the DPD protein. Only the effect of the Ile370Val and a previously identified Cys29Arg mutation could not be readily explained by analysis of the three-dimensional structure of the DPD enzyme, suggesting that at least the latter might be a common polymorphism. Our data demonstrate for the first time the possible consequences of missense mutations in the DPD gene on the function and stability of the DPD enzyme.
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| 4. |
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| 5. |
- Cunnea, Paula M, et al.
(author)
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ERdj5, an endoplasmic reticulum (ER)-resident protein containing DnaJ and thioredoxin domains, is expressed in secretory cells or following ER stress.
- 2003
-
In: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 278:2, s. 1059-66
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Journal article (peer-reviewed)abstract
- A complex array of chaperones and enzymes reside in the endoplasmic reticulum (ER) to assist the folding and assembly of and the disulfide bond formation in nascent secretory proteins. Here we characterize a novel human putative ER co-chaperone (ERdj5) containing domains resembling DnaJ, protein-disulfide isomerase, and thioredoxin domains. Homologs of ERdj5 have been found in Caenorhabditis elegans and Mus musculus. In vitro experiments demonstrated that ERdj5 interacts via its DnaJ domain with BiP in an ATP-dependent manner. ERdj5 is a ubiquitous protein localized in the ER and is particularly abundant in secretory cells. Its transcription is induced during ER stress, suggesting potential roles for ERdj5 in protein folding and translocation across the ER membrane.
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| 6. |
- Eichberger, Arno, et al.
(author)
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Pressure measurements in the spinal canal of post-mortem human subjects during rear-end impact and correlation of results to the neck injury criterion.
- 2000
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In: Accident Analysis and Prevention. ; 32:2, s. 251-60
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Journal article (peer-reviewed)abstract
- The aim of this study is to validate the pressure effect theory on human beings during a realistic rear-end impact and to correlate the neck injury criterion to pressure in the spinal canal. Sled experiments were performed using a test setup similar to real rear-end collisions. Test conditions were chosen based on accident statistics and recordings of real accidents. In particular, velocity change and acceleration level were reproduced similar to actual collisions. The head restraint as well as the seat back were adjusted to different positions. Two small pressure transducer were implemented to the spinal canal of postmortem human subjects and pressure measurement similar to the pig experiments (using exactly the same equipment) were performed. A total set of 21 experiments with four different subjects were performed. The subjects were additionally instrumented with triaxial accelerometers that allowed for calculation of the NIC criterion. Results showed that NIC and pressure amplitudes of the CSF correlate well and therefore NIC seems to be able to predict these amplitudes also for human beings. Conclusions whether these pressure effects induce soft tissue neck injuries or not could not be drawn and should be investigated in further research.
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| 7. |
- Flinn, Elizabeth M, et al.
(author)
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Recruitment of Gen5-containing complexes during c-Myc-dependent gene activation - Structure and function aspects
- 2002
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In: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 277:26, s. 23399-23406
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Journal article (peer-reviewed)abstract
- The N-terminal domain of c-Myc plays a key role in cellular transformation and is involved in both activation and repression of target genes as well as in modulated proteolysis of c-Myc via the proteasome. Given this functional complexity, it has been difficult to clarify the structures within the N terminus that contribute to these different processes as well as the mechanisms by which they function. We have used a simplified yeast model system to identify the primary determinants within the N terminus for W chromatin remodeling of a promoter, (ii) gene activation from a chromatin template in vivo, and (iii) interaction with highly purified Gcn5 complexes as well as other chromatin-remodeling complexes in vitro. The results identify two regions that contain autonomous chromatin opening and gene activation activity, but both regions are required for efficient interaction with chromatin-remodeling complexes in vitro. The conserved Myc boxes do not play a direct role in gene activation, and Myc box II is not generally required for in vitro interactions with remodeling complexes. The yeast SAGA complex, which is orthologous to the human GCN5-TRRAP complex that interacts with Myc in human cells, plays a role in Myc-mediated chromatin opening at the promoter but may also be involved in later steps of gene activation.
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| 8. |
- Hardalupas, Y, et al.
(author)
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Chemiluminescence sensor for local equivalence ratio of reacting mixtures of fuel and air (FLAMESEEK)
- 2004
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In: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 24:11-12, s. 1619-1632
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Journal article (peer-reviewed)abstract
- This paper describes a Cassegrain optics-based chemiluminescence sensor (CS) for measurements in gas turbine combustors. The chemiluminescence sensor measures the equivalence ratio of reacting fuel and air mixtures, and can identify the flame location, in partially premixed flames. It has the potential for monitoring the degree of premixedness of reacting fuel and air in industrial gas turbine combustors, where operation with lean premixed mixtures is important for reduction of NO, emissions. The spatial resolution of the sensor is evaluated by comparing OH* chemiluminescence measurement from the CS with laser induced OH fluorescence, in the cone-shaped premixed flame of a Bunsen burner. The ability of the sensor to measure in a modified micro-gas turbine environment burning a methane/air, as well as, a methane/ water/air flame (humidified flame) is also demonstrated.
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| 9. |
- Heintzenberg, J, et al.
(author)
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Number and sulfur derived 3-parameter aerosol size distributions in the tropopause region from CARIBIC flights between Germany and the Indic
- 2002
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In: Journal of Aerosol Science. - 0021-8502. ; 33:4, s. 595-608
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Journal article (peer-reviewed)abstract
- Aerosol number concentrations in three size ranges (d(p) > 4, d(p) > 12, 18 less than or equal to, dp less than or equal to, 135 nm) and sulfur mass from impactor samples were collected over a total of about 120 sampling hours on 18 long-range commercial flights between the northern mid-latitudes and the equatorial region covering an altitude range between 8.8 and 11.2 km. The data were evaluated with a new random search algorithm to derive monomodal lognormal particle size distributions. Through tests of the algorithm using synthetic data and size distributions from mountain stations the retrieval capabilities of the fitting algorithm are established. The fitting of aerosol data yields three parameters of the submicrometer size distribution. Their latitudinal trends indicate the influence of tropical and mid-latitudinal source regions on the tropopause aerosol. Total particle numbers show maxima near tropical biomass burning, and over the European regions. Geometric mean diameters decrease north of 35degreesN while the width of the distribution increases, indicating a move towards more frequent recent nucleation events or more frequent bimodal size distributions. (C) 2002 Elsevier Science Ltd. All rights reserved.
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| 10. |
- Hermann, DS, et al.
(author)
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Electro-optic modulation of light by a planar waveguide based on ferroelectric liquid crystals
- 2000
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In: Molecular Crystals and Liquid Crystals Science and Technology. - 1058-725X. ; 352, s. 813-
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Journal article (peer-reviewed)abstract
- We present electro-optic switching from a planar waveguide with a ferroelectric liquid crystal overlayer and discuss the operating principle and the parameters significant for the operation of the device. We have found electro-optic response times of about 20 mus at best as well as a high (5.7%) transmittance in the ON-state of the device. The contrast ratio was 4:1 ON to OFF state.
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