Search Results - (Author, Cooperation:K. Kramer)

2015-11-03

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Biomarkers/metabolism ; Brain/cytology/*metabolism ; Cell Line, Tumor ; Endothelial Cells/cytology/metabolism ; Epithelial Cells/cytology/metabolism ; Exosomes/*metabolism ; Female ; Fibroblasts/cytology/metabolism ; Genes, src ; Humans ; Integrin alpha6beta1/metabolism ; Integrin alpha6beta4/antagonists & inhibitors/metabolism ; Integrin beta Chains/metabolism ; Integrin beta4/metabolism ; Integrins/antagonists & inhibitors/*metabolism ; Kupffer Cells/cytology/metabolism ; Liver/cytology/*metabolism ; Lung/cytology/*metabolism ; Mice ; Mice, Inbred C57BL ; Neoplasm Metastasis/*pathology/*prevention & control ; Organ Specificity ; Phosphorylation ; Receptors, Vitronectin/antagonists & inhibitors/metabolism ; S100 Proteins/genetics ; *Tropism

1432-1041

Genetic polymorphism ; 8-hydroxyclomipramine ; glucuronidation ; P450 isozymes ; glucuronyl transferase ; co-regulation

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Medicine

Electronic Resource

article

1993

Verfahrenschemie ; Anorganische Chemie ; Chemie ; Metall ; Titan ; Legierung ; Naturwissenschaften ; Herstellung

Praxis der Naturwissenschaften. Chemie, Bd. 42 (1993) H. 5, S. 2-8, 0177-9516

0342-8745

German

Literaturangaben

1089-7550

AIP Digital Archive

Physics

Nonequilibrium Si1−xCx alloys produced by pulsed laser induced epitaxy from ion implanted Si have been studied in the concentration range from 0.35 to 3.8 at. % C. Films were formed by multiple energy ion implantation of carbon into {001} Si to produce nearly uniform composition profiles, followed by irradiation with a 308 nm, 30 ns excimer laser pulse. Heteroepitaxy proceeded from the underlying {001} Si through the carbon containing layer at approximately 5 m/s. Transmission electron microscopy, Fourier transform infrared spectroscopy, high resolution x-ray diffraction, ion channeling, and secondary-ion mass spectrometry were used to characterize the structure and composition. At low concentrations, the films are fully strained and the carbon is substitutional. At concentrations exceeding 1.4 at. % C, SiC precipitates were observed and the substitutional carbon concentration decreased. © 1996 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report initial results of a novel technique for epitaxial growth of GexSi1−x alloys on single-crystal Si. During electron beam deposition of amorphous GexSi1−x, an incident XeCl excimer laser, operating at 308 nm with a 30 ns pulse duration, melts and crystallizes the amorphous layer in situ after each ≈5 nm of deposition. This laser-induced melt extends approximately 20 nm and provides epitaxy from the underlying substrate (or previous layers) at each stage of deposition. This melt/solidification process can be repeated continuously until the final desired alloy thickness is achieved. For layers up to 260 nm with Ge concentrations of 1.5–3 at. %, MeV ion channeling and cross-sectional transmission electron microscopy confirm epitaxial growth.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Heteroepitaxy of Si1−xGex/Si alloy layers on Si (100) substrates has been achieved using pulsed laser induced epitaxy (PLIE). The energy of 1 to 20 pulses from a spatially homogenized XeCl excimer laser beam is used to melt a structure consisting of electron-beam evaporated Ge on Si (100) substrates. Alloy films with different Ge fractions are investigated and films with up to 21% Ge content are found to exhibit excellent crystallinity, as confirmed by MeV-ion channeling along the 〈100〉 direction. MeV-ion channeling is also used to determine the level of strain in the layers. This is done by comparing angular yield curves around the 〈110〉 direction for the substrate and alloy layer. The strain values obtained match with calculations for an ideally strained layer state. The strain is also measured for layers that have been subjected to different thermal cycles. A high level of strain is preserved in the alloy layer even after heating to 950 °C for 1 h. This unusual thermal stability is believed to be due to two process features, the ultrarapid nature of the process and the interfacial grading of the Ge fraction created during the melt-regrowth process.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The epitaxial quality of GexSi1−x films grown on Si〈100〉 by a novel laser-assisted technique has been investigated for compositions in the range x≤0.37 and thicknesses between 50 and 500 nm. Epitaxy is induced during electron beam deposition of GexSi1−x films on Si substrates by pulses of an excimer laser operating at 308 nm with 30 ns pulse duration. Good epitaxial growth is obtained for 50 nm films for x≤0.04 on chemically cleaned Si(100) surfaces even in the presence of substantial fluorine coverage. Using a predeposition/crystallization of a 50 nm pure-Si buffer layer, good epitaxy is then obtained in 50 nm films for x=0.05–0.13. At x=0.07, defect-free alloys have been grown up to thicknesses of 0.5 μm. However, for films with compositions above 19 at.% Ge, dislocations at a nearly constant density of ≈10 μm/μm2 are observed. This uniform density suggests a breakdown mechanism other than simple strain relaxation.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

High quality heteroepitaxial regrowth of arsenic-implanted a-Si on Si1−xGex layers with Ge fractions between 0 and 0.2 is accomplished using pulsed laser induced epitaxy (PLIE). The structures of boron-doped Si1−xGex on Si(100) are created beforehand using a combination of (PLIE) and gas immersion laser doping. A small amount of Ge and B backdiffusion from the Si1−xGex film into the top Si layer is observed. During the laser pulse, the implanted arsenic diffuses up to the maximum melt depth so that melt depth and junction depth coincide. The a-Si is sputter deposited to a thickness of 900 A(ring), and the As is implanted to a dose of 5×1014 cm−2 at 40 keV. A single XeCl excimer laser pulse with an energy fluence to be selected between 0.6 and 0.8 J/cm2 is sufficient to heteroepitaxially regrow the a-Si and activate the implanted arsenic.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The selective fabrication of ultrashallow p+/n junctions in silicon using projection gas immersion laser doping is reported. The method offers substantial improvement and simplification in junction formation to integrated circuit manufacturers, since several processing steps required for conventional doping techniques like ion implantation are eliminated. Spatially selective incorporation of boron into silicon without the use of any masking layer on the wafer surface is achieved. A pulsed excimer laser beam is patterned using a chromeless reticle and the pattern is transferred through a projection system onto a wafer that is kept in a BF3 dopant gas ambient. The depth of the fabricated junctions is 60 nm with a surface concentration of 5×1019 cm−3. The vertical and lateral distribution of boron in silicon after patterned laser processing is investigated using secondary ion mass spectroscopy (SIMS) and time-of-flight SIMS (ToF-SIMS). Vertical and lateral dopant profiles are steep and clearly resolved. © 1996 American Institute of Physics.

Electronic Resource

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

To evaluate the potential responses of individual trees to climatic warming, phenological observations of clones of Larix decidua (Mill.), Betula pubescens (Ehrh.), Tilia cor-data (Mill.), Populus canescens (Ait.), Quercus robur (L.), Fagus sylvatica (L.) and Picea abies (L.) relocated over a large latitudinal range in Europe were analysed. The magnitude of the response of the clone was compared to that of genetically different trees of the same species in part of the latitudinal range, which were assumed to have adapted to their local climates. It was found that the responses of the date of leaf unfolding and the date of leaf fall in the clones to temperature were similar in magnitude to those in the genetically different trees. This demonstrates that trees possess considerable plasticity and are able to respond phenotypically to a major change in their local climate.For the clones of Larix decidua and Quercus robur the duration of the growing season may decrease with increasing temperature, because leaf fall is advanced more than leaf unfolding. In Betula pubescens and Populus canescens, leaf unfolding and leaf fall are advanced equally, whereas in Tilia cordata and Fagus sylvatica the date of leaf fall seems to be unaltered but the date of leaf unfolding advances with increasing temperature. These differences in the duration of the growing season at increased temperature may alter the competitive balance between the species.Descriptive dynamic models showed that most of the variance in the date of leaf unfolding can be accounted for by temperature. However, a generally applicable model of leaf fall based on temperature and/or photoperiod could not improved the null model, i.e. the mean date of leaf fall, because of variability in other environmental factors.The lowest temperatures around the dates of leaf unfolding and leaf fall differed among the clones. The hypothesis that the survival of the clones is curtailed by spring frosts was supported. Thus, these lowest temper-tures around leaf unfolding may represent thresholds below which the species cannot survive. It is argued that these thresholds may be a particularly sensitive means to evaluate the impact of climatic warming on the geographical distribution of tree species.

Electronic Resource

1365-3040

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Two studies presented in the literature (Murray, Canned & Smith 1989; Hanninen 1991) evaluate the effect of increasing winter temperature on the probability of spring frost damage to trees, but yield contradictory results. It is unclear whether the disparity can be ascribed to the fact that different models were used, or is the result of different climatic warming scenarios being used, or is because the tree species at the different locations do indeed respond differently to warmer winters. To evaluate the effects of climatic warming to tree species in The Netherlands and in Germany, both models were fitted to long series of observations on the date of leaf unfolding of eleven tree species. The impact of the two scenarios (uniformly and non-uniformly changing winter temperature) on the date of leaf unfolding and on the probability of freezing temperature around that date was evaluated. To test the importance of adaptation to local climate, hypothetical provenance transfers were analysed. It was concluded that, for tree species in The Netherlands and Germany, the probability of spring frost damage will decrease. The contradictory results found in the literature could be ascribed to differences between provenances adapted to their local climate, and is not because different models and different climatic warming scenarios were used in these studies.

Electronic Resource

1365-2486

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Energy, Environment Protection, Nuclear Power Engineering

Geography

Reliable models are required to assess the impacts of climate change on forest ecosystems. Precise and independent data are essential to assess this accuracy. The flux measurements collected by the EUROFLUX project over a wide range of forest types and climatic regions in Europe allow a critical testing of the process-based models which were developed in the LTEEF project. The ECOCRAFT project complements this with a wealth of independent plant physiological measurements. Thus, it was aimed in this study to test six process-based forest growth models against the flux measurements of six European forest types, taking advantage of a large database with plant physiological parameters.The reliability of both the flux data and parameter values itself was not under discussion in this study. The data provided by the researchers of the EUROFLUX sites, possibly with local corrections, were used with a minor gap-filling procedure to avoid the loss of many days with observations.The model performance is discussed based on their accuracy, generality and realism. Accuracy was evaluated based on the goodness-of-fit with observed values of daily net ecosystem exchange, gross primary production and ecosystem respiration (gC m−2 d−1), and transpiration (kg H2O m−2 d−1). Moreover, accuracy was also evaluated based on systematic and unsystematic errors. Generality was characterized by the applicability of the models to different European forest ecosystems. Reality was evaluated by comparing the modelled and observed responses of gross primary production, ecosystem respiration to radiation and temperature. The results indicated that: Accuracy. All models showed similar high correlation with the measured carbon flux data, and also low systematic and unsystematic prediction errors at one or more sites of flux measurements. The results were similar in the case of several models when the water fluxes were considered. Most models fulfilled the criteria of sufficient accuracy for the ability to predict the carbon and water exchange between forests and the atmosphere. Generality. Three models of six could be applied for both deciduous and coniferous forests. Furthermore, four models were applied both for boreal and temperate conditions. However, no severe water-limited conditions were encountered, and no year-to-year variability could be tested. Realism. Most models fulfil the criterion of realism that the relationships between the modelled phenomena (carbon and water exchange) and environment are described causally. Again several of the models were able to reproduce the responses of measurable variables such as gross primary production (GPP), ecosystem respiration and transpiration to environmental driving factors such as radiation and temperature. Stomatalconductance appears to be the most critical process causing differences in predicted fluxes of carbon and water between those models that accurately describe the annual totals of GPP, ecosystem respiration and transpiration.As a conclusion, several process-based models are available that produce accurate estimates of carbon and water fluxes at several forest sites of Europe. This considerable accuracy fulfils one requirement of models to be able to predict the impacts of climate change on the carbon balance of European forests. However, the generality of the models should be further evaluated by expanding the range of testing over both time and space. In addition, differences in behaviour between models at the process level indicate requirement of further model testing, with special emphasis on modelling stomatal conductance realistically.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] In the best studied insects, the hyperglycaemic hormone functions similarly to glucagon in vertebrates: the hormone increases carbohydrate levels in the circulating haemolymph in vivo and stimulates glycogenolysis and the activation of phosphorylase in the fat body in vitro5-6'17〉18. By several ...

Electronic Resource

0020-1693

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0014-5793

(Lung) ; Muscarinic receptor ; Selenium ; Vitamin E ; β-Adrenergic receptor

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

0022-2313

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource

0022-1910

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0022-2313

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource

0022-328X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

0022-328X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource