Showing papers by "University of Stuttgart published in 1996"
TL;DR: The ER degradation system was studied with yeast mutants defective in the breakdown of a mutated soluble vacuolar protein, carboxypeptidase yscY (CPY*), where it is likely that CPY* entered the ER, was glycosylated, and was then transported out of the ER lumen to the cytoplasmic side of the organelle, where it was conjugated with ubiquitin and degraded.
Abstract: Secretion of proteins is initiated by their uptake into the endoplasmic reticulum (ER), which possesses a proteolytic system able to degrade misfolded and nonassembled proteins The ER degradation system was studied with yeast mutants defective in the breakdown of a mutated soluble vacuolar protein, carboxypeptidase yscY (CPY*) The ubiquitin-conjugating enzyme Ubc7p participated in the degradation process, which was mediated by the cytosolic 26S proteasome It is likely that CPY* entered the ER, was glycosylated, and was then transported back out of the ER lumen to the cytoplasmic side of the organelle, where it was conjugated with ubiquitin and degraded
712 citations
TL;DR: In this paper, a boron-containing silicon nitride/carbide ceramic that does not degrade at temperatures up to 2,000 °C even in nitrogen-free environments is presented.
Abstract: CERAMICS based on silicon nitride and carbide are strong and stable at high temperatures, and are therefore under investigation for the fabrication of motor and turbine parts1–3. But silicon nitride decomposes at about 1,400 °C in vacuum and 1,775 °C in 0.1 MPa nitrogen4,5, limiting the high-temperature range of its technological uses. Here we describe a boron-containing silicon nitride/carbide ceramic that does not degrade at temperatures up to 2,000 °C even in nitrogen-free environments. We synthesize the material in a polymer-to-ceramic transformation6 from a single polymeric polyborosilazane precursor. On heating at 1,000 °C in argon we obtain a ceramic with the composition Si3.0B1.0C4.3N2.0. The ceramic begins to convert to a polycrystalline composite of silicon nitride and carbide (with some non-crystalline boron nitride) at 1,700 °C, a process that is completed (without substantial change in elemental composition) at 2,000 °C.
634 citations
TL;DR: Contrary to the poor inhibition of PKCμ by Gö 6983, this compound was found to suppress in vitro kinase activity ofPKC isoenzymes from all three subgroups very effectively with IC50 values from 7 to 60 nM.
612 citations
TL;DR: The brain is considered as a complex, physical, and open system that exhibits spatiotemporal behavior at various time and length scales and a nonlinear dynamics and a spatial interconnection of its elements, the neurons is considered.
Abstract: The brain is considered as a complex, physical, and open system that exhibits spatiotemporal behavior at various time and length scales. A necessary condition for this pattern forming character of the brain is a nonlinear dynamics and a spatial interconnection of its elements, the neurons. The functional behavior of the brain is encoded in these spatiotemporal structures and can, at least partly, be extracted from the dynamics of the macroscopic quantities measured by the EEG and MEG. According to synergetics [1], this extraction contains all the relevant information about the spatiotemporal behavior of the brain and has, in general, a small number of degrees of freedom. This idea has been formalized to the order parameter conceptbased on circular causality: The order parameters are determined and created by the cooperation of microscopic quantities, but at the same time the order parameters govern the behavior of the whole system. Based on this approach phenomenological models were set up in the past for different experiments in order to find evolution equations that describe the experimentally observed macroscopic dynamics [2].
454 citations
TL;DR: Copper is a bioessential element in biology with truly unique chemical characteristics in its two relevant oxidation states +I and +II as discussed by the authors, and significant progress has been made in recent years in the elucidation of the frequently surprising biochemistry of this trace element.
Abstract: Copper is a bioessential element in biology with truly unique chemical characteristics in its two relevant oxidation states +I and +II. Significant progress has been made in recent years in the elucidation of the frequently surprising biochemistry of this trace element. Those advances were especially furthered through mutual stimulation involving results from biochemistry, molecular biology, and medicine on one hand and the synthesis as well as the structural and spectroscopic characterization of low molecular weight model complexes on the other. The most notable features of protein-bound active copper are its almost exclusive function in the metabolism of O2 or N/O compounds (NO, N2O) and its frequent association with oxidizing organic and inorganic radicals such as tyrosyl, semiquinones, superoxide, or nitrosyl. This unique biological role of copper can be rationalized given its chemical and assumed evolutionary background.
438 citations
TL;DR: In DER1‐deleted cells, a substrate protein for ER degradation is retained in the ER by the same mechanism which also retains lumenal ER residents, which suggests that D ER1 acts in a process that directly removes protein from the folding environment of the ER.
Abstract: The endoplasmic reticulum (ER) of the yeast Saccharomyces cerevisiae contains of proteolytic system able to selectively degrade misfolded lumenal secretory proteins. For examination of the components involved in this degradation process, mutants were isolated. They could be divided into four complementation groups. The mutations led to stabilization of two different substrates for this process. The mutant classes were called 'der' for 'degradation in the ER'. DER1 was cloned by complementation of the der1-2 mutation. The DER1 gene codes for a novel, hydrophobic protein, that is localized to the ER. Deletion of DER1 abolished degradation of the substrate proteins. The function of the Der1 protein seems to be specifically required for the degradation process associated with the ER. The depletion of Der1 from cells causes neither detectable growth phenotypes nor a general accumulation of unfolded proteins in the ER. In DER1-deleted cells, a substrate protein for ER degradation is retained in the ER by the same mechanism which also retains lumenal ER residents. This suggests that DER1 acts in a process that directly removes protein from the folding environment of the ER.
391 citations
TL;DR: Proteasomes are large multi-subunit protease complexes that selectively degrade intracellular proteins that operate in the stress response, by removing abnormal proteins, and in the immuneresponse, by generating antigenic peptides.
388 citations
TL;DR: In this article, the systematics and fragmentation of the M1 Scissors Mode in even-even rare earth and actinide nuclei, its deformation dependence and saturation behavior, the existence of the Scissors mode in odd deformed nuclei and 2 + ⊗ 3 − two-phonon E1 excitations in N =82 isotones and Z =50 isotopes.
314 citations
16 Nov 1996
TL;DR: An improved version of an existing distributed algorithm for concurrency control that is based on operation transformations is presented and a set of necessary and sufficient conditions to be satisfied in order to ensure consistency in a replicated architecture is presented.
Abstract: Concurrency control and group undo are important issues in the design of groupware, especially for interactive group editors. We present an improved version of an existing distributed algorithm for concurrency control that is based on operation transformations. Since the usability of the algorithm relies on its formal correctness, we present a set of necessary and sufficient conditions to be satisfied in order to ensure consistency in a replicated architecture. We identify desirable properties of operation transformations and show how our approach can be employed to implement group undo. The approach has been applied to build a prototypical group editor for text; some experiences gained are presented.
300 citations
TL;DR: In this article, an algorithm for the numerical computation of so-called consistent tangent moduli in finite inelasticity is presented, where the moduli determine the sensitivity of algorithmic expressions for stresses with respect to the change in total deformation.
289 citations
TL;DR: In this paper, the performance of large core pseudopotentials (ECP), simulating X + cores (X = K, Rb, Cs), and corresponding core-polarization potentials (CPP) is critically analyzed in calculations for bond lengths r e, dissociation energies D e, and vibrational frequencies ω e of alkali fluorides XF.
TL;DR: This paper shows how to construct a logically consistent fluid-dynamic traffic model from basic laws for the acceleration and interaction of vehicles from the gas-kinetic traffic equation of Paveri-Fontana.
Abstract: Macroscopic traffic models have recently been severely criticized to base on lax analogies only and to have a number of deficiencies. Therefore, this paper shows how to construct a logically consistent fluid-dynamic traffic model from basic laws for the acceleration and interaction of vehicles. These considerations lead to the gas-kinetic traffic equation of Paveri-Fontana. Its stationary and spatially homogeneous solution implies equilibrium relations for the `fundamental diagram', the variance-density relation, and other quantities which are partly difficult to determine empirically.
Paveri-Fontana's traffic equation allows the derivation of macroscopic moment equations which build a system of non-closed equations. This system can be closed by the well proved method of Chapman and Enskog which leads to Euler-like traffic equations in zeroth-order approximation and to Navier-Stokes-like traffic equations in first-order approximation. The latter are finally corrected for the finite space requirements of vehicles. It is shown that the resulting model is able to withstand the above mentioned criticism.
TL;DR: It is proposed that import of aminopeptidase I into the vacuole shares a number of components required for bulk autophagocytosis, but is made specific, saturable, and constitutive by the presence of a receptor or other interacting protein(s).
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TL;DR: A scan-based BIST scheme is presented which guarantees complete fault coverage with very low hardware overhead, and it is shown that the output of an LFSR which feeds a scan path has to be modified only at a few bits in order to transform the random patterns into a complete test set.
Abstract: A scan-based BIST scheme is presented which guarantees complete fault coverage with very low hardware overhead. A probabilistic analysis shows that the output of an LFSR which feeds a scan path has to be modified only at a few bits in order to transform the random patterns into a complete test set. These modifications may be implemented by a bit-flipping function which has the LFSR-state as an input, and flips the value shifted into the scan path at certain times. A procedure is described for synthesizing the additional bit-flipping circuitry, and the experimental results indicate that this mixed-mode BIST scheme requires less hardware for complete fault coverage than all the other scan-based BIST approaches published so far.
24 Mar 1996
TL;DR: An overview of the emerging field of intelligent agents (IAs) by identifying their basic properties and looking at their potential impacts on open service architectures, intelligent communications and network management.
Abstract: The telecommunications environment is changing its face towards an open market of information services where the vision is "information any time, at any place, in any form". Within this electronic market the aspects of service customization and instant service provision are of fundamental importance. In this context a new paradigm is gaining momentum referred to as "intelligent agents". This paper provides an overview of the emerging field of intelligent agents (IAs) by identifying their basic properties. Focusing on mobile agents, which could be considered as a specific class of intelligent agents, we identify the chances of agent technology in the context of telecommunications. We look at their potential impacts on open service architectures, intelligent communications and network management.
TL;DR: The enzyme had a temperature optimum of 42°C and was slightly oxygen-sensitive and was thermolabile above 50°C, and the apparent molecular mass of the native enzyme was determined by gel filtration to be 58 kDa.
TL;DR: In this paper, the electron localization function (ELF) was calculated for the atoms Li to Sr and the ELF maxima reveal the atomic shell structure for all these atoms and the shells are separated from each other by ELF minima.
Abstract: rn The electron localization function (ELF) was calculated for the atoms Li to Sr The ELF maxima reveal the atomic shell structure for all these atoms The shells are separated from each other by ELF minima The integration of the electron density in a shell gives electron numbers For the valence shell those are in good agreement with the ones expected from the Periodic Table of Elements 0 1996 John Wiley & Sons, Inc
TL;DR: This paper reviews multinuclear solid-state NMR studies of Brønsted acid sites in zeolites and discusses the formation, accessibility and localization of hydroxyl protons, dehydroxylation and geometry and parameters of the local structure of OH groups in these materials.
TL;DR: Based on a sequence comparison with the antennal binding proteins from different moth species, one of the clones appears to encode a pheromone binding protein, whereas two others represent new members of the two general odorant binding protein families.
TL;DR: An expression library was generated by partial Sau3A digestion of genomic DNA from the thermophile Bacillus thermocatenulatus and cloning of DNA fragments in pUC18 in Escherichia coli DH5alpha, showing high stability at pH 9.0-11.0 and towards various detergents and organic solvents.
TL;DR: In this paper, a survey of machine learning techniques that seem to be applicable in realizing systems with intelligent behavior is presented, together with hybrid solutions which try to integrate the benefits of the individual techniques.
TL;DR: In this paper, the sulfonation of arylene polymers with an ion exchange capacity of 0.5 to 3.2 mequiv SO3H/g polymers has been investigated.
Abstract: A new process has been developed for the sulfonation of arylene polymers which can be lithiated, like polysulfone Udel®. The sulfonation process consists of the following steps: (1) lithiation of the polymer at temperatures from −50 to −80°C under argon, (2) gassing of the lithiated polymer with SO2; (3) oxidation of the formed polymeric sulfinate with H2O2, NaOCl, or KMnO4; (4) ion-exchange of the lithium salt of the sulfonic acid in aqueous HCl. The advantages of the presented sulfonation procedure are: (1) in principle all polymers which can be lithiated can be subjected to this sulfonation process; (2) by this sulfonation procedure the sulfonic acid group is inserted into the more hydrolysis-stable part of the molecule; (3) this process is ecologically less harmful than many common sulfonation procedures. The sulfonated polymers were characterized by NMR, titration and elemental analysis, by IR spectroscopy, and by determination of ionic conductivity. Also the hydrolytic stability of the sulfonated ion-exchange polymers was investigated. Polymers with an ion-exchange capacity of 0.5 to 3.2 mequiv SO3H/g Polymer have been synthesized and characterized. The following results have been achieved: membranes made from the sulfonated polymers show good conductivity, good permselectivity (>90%), and good hydrolytic stability in 1N HCl and water at temperatures up to 80°C. © 1996 John Wiley & Sons, Inc.
TL;DR: In this paper, the effects of stoichiometry and residence time in the fuel-rich zone and effects of temperature were evaluated for air staging with different coals and, in the case of reburning, for different gaseous reburn fuels.
TL;DR: In this paper, the mechanical performance of various 3D woven composites (monolithic and sandwich) by comparison of in-plane properties (stiffness and strength), damage tolerance, energy absorption capability and fracture mechanical properties is presented.
TL;DR: The combination of the reductive potential of anaerobic microbes with subsequent oxidative processes opens a hitherto largely unexploited technology for biological treatment of waste water and for soil bioremediation.
TL;DR: In this paper, the alignment of energy bands in polycrystalline thin films starting with the molybdenum coated soda lime glass was analyzed with photoelectron spectroscopy techniques.
TL;DR: In this paper, the fabrication of a 11.4% efficient thin film solar cell based on CuInS2 with an Inx(OH,S)y buffer layer is described.
TL;DR: In this paper, the authors used the 6-31G* basis set to calculate the scale factor of the BVWN force field and showed that the effect of the basis set on the calculated bond angles, frequencies, and scale factors was minor.
Abstract: Optimized geometries, vibrational frequencies, and scale factors were calculated for furan and thiophene with the HF, MP2, LDA, BVWN, BLYP, and B3LYP methods of theory using the 6-31G**, cc-pVDZ, and cc-pVTZ basis sets. The agreement between the optimized and experimental geometries was in the order B3LYP, MP2, LDA, BVWN, BLYP, then HF. The calculated frequencies by the unscaled BVWN force field had the smallest average error in the mid-IR region, but using one-scale-factor scaling, those calculated by the scaled B3LYP force field had the lowest average error. Using one-scale-factor scaling, scale factors of 0.82, 0.89, 0.98, 0.93, 0.96, and 0.96 were obtained by the HF, MP2, BLYP, B3LYP, LDA, and BVWN force fields, respectively, using the 6-31G** basis set. The effect of the basis set on the calculated bond angles, frequencies, and scale factors by the DFT methods was minor, but except with the LDA method, the agreement between the calculated and experimental bond lengths can be arranged in the order cc-...
TL;DR: This paper outlines specific methodologies for conducting research via computer networks and point out pitfalls and suggest a range of potential solutions in terms of specific practical techniques for managing the design, dissemination, and collection of Internet materials.
Abstract: This paper outlines specific methodologies for conducting research via computer networks. We discuss advantages of Internet experimentation over previous modes of telecommunication-facilitated research and characterize features of studies that can benefit from Internet access and those which are unlikely to. We point out pitfalls and suggest a range of potential solutions in terms of specific practical techniques for managing the design, dissemination, and collection of Internet materials. We also discuss techniques for minimizing attrition and for adapting to recalcitrance presented by “hacker” vandalism.