Showing papers by "Technical University of Berlin published in 1988"
TL;DR: In this article, a casual model of ecologically concerned consumers is analyzed by the LISREL approach to predict five different patterns of environmentally responsible consumption, and the results suggest that each behavioral pattern has its own cluster of predictors.
575 citations
Journal Article•
TL;DR: The organization of the book follows the plan of the meeting, with chapters representing the general meeting sessions and articles representing the meeting presentations, and each section labeled workshop addresses a specific topic.
Abstract: New digital imaging modalities and more sophisticated image processing systems will have a profound effect on those areas of medicine concerned with imaging. This mainly means computer-assisted radiology (CAR) and implies a transition from analog film systems to digital imaging systems, integration of digital imaging modalities through picture archiving and communication systems (PACS) and the graduated employment of image-oriented medical work stations (MWS) for computer-assisted representation, communication, diagnosis, and therapy planning.
209 citations
01 Jan 1988
TL;DR: The cyclopentadienyl metallocene diacido complexes (C5H5)2MX2 have been shown to exhibit antiproliferative properties in vivo and in vitro.
Abstract: Cyclopentadienyl metal complexes are organometallic compounds which exhibit antiproliferative properties in vivo and in vitro. They are represented by compounds of various structural type. The metallocene diacido complexes (C5H5)2MX2 contain early transition metal atoms such as titanium(IV) and vanadium(IV), the ionic metallicenium salts [(C5H5)2M]+X− include medium transition metals, e.g. iron(III), whereas the uncharged decasubstituted metallocenes (C5R5)2M comprise the main group elements tin(II) and germanium(II) as central metal atoms M. A variety of biological data are available about metallocene diacido complexes, especially titanocene dichloride. These substances exhibit antitumor properties against numerous experimental tumors, e.g. Ehrlich ascites tumor, B 16 melanoma, colon 38 carcinoma, Lewis lung carcinoma, as well as against various human tumors heterotransplanted to athymic mice. Biological experiments using (C5H5)2TiCl2 and (C5H5)2VCl2 pointed to the nucleic acids as a probable target for metallocene diacido complexes within the cells, revealed a main accumulation of titanium or vanadium in the liver and the intestine and unfolded a pattern of organ toxicity which fundamentally differs from that of other cytostatic drugs. These biological features confirm the cyclopentadienyl metal complexes to be an independent group of non-platinum-group metal antitumor agents being characterized by unusual biological properties. They represent interesting candidates for future biological and clinical investigations.
171 citations
TL;DR: In this article, a measurement model of retail store image that captures the customer perception of strategic variables like quality and price level is tested and used to predict a marketing outcome measure as an indicator for business success.
167 citations
TL;DR: The viscosity and temperature-controlled dynamical behavior of rhodamine dyes in the excited state has been investigated by stationary and time-resolved fluorescence measurements using synchrotron radiation.
157 citations
148 citations
TL;DR: Coherent structures as discussed by the authors have been defined as regions of concentrated vorticity, characteristic and flow-specific organization, recurrence, appreciable lifetime and scale, and have been the primary object of scientific curiosity and dispute in turbulence research.
146 citations
TL;DR: A re-analysis of the data showed that the results of Frey and Weck-Hannemann's model are extremely unstable, and cannot be regarded as reliable statements about the shadow economy of these 17 countries as mentioned in this paper.
137 citations
TL;DR: In this paper, a 7-year-old tillage trial, comprising conventional tillage, minimum tillage and no-tillage, was chosen to study the relative importance of controlled mulch rates and soil physical properties such as bulk density, pore volume and hydraulic conductivity upon infiltrability.
Abstract: A 7-year-old tillage trial, comprising conventional tillage (CT), minimum tillage (MT) and no-tillage (NT), was chosen to study the relative importance of controlled mulch rates and soil physical properties such as bulk density, pore volume and hydraulic conductivity upon infiltrability. Infiltration measurements were carried out with a portable rainfall simulator. Mulch consisted of soya bean residues. Soil physical analysis showed higher bulk densities in the top 20 cm under NT, whereas CT, and to a lesser extent MT, led to the development of a plough pan in 20–30 cm depth. At the same time, compaction brought about a decrease in macropores and an increase in micropores. Total porosity ranged between 56.6% and 66.4%. Hydraulic conductivity did not differ significantly between tillage systems, and overall conductivity values were very high. The main factor influencing infiltrability was the formation of a surface seal depending on the degree of soil cover by mulch, irrespective of tillage system. For all 3 tillage systems, a 100% soil cover led to the complete infiltration of a 60-mm rainfall, whereas only 20% of the applied rain infiltrated when the soil was bare and the surface completely sealed. Plant residues of 4–6 t ha −1 are proposed, as the minimum amount of mulch needed to reduce runoff and erosion effectively.
135 citations
TL;DR: Two methods of biotope mapping and species recording in urban areas are presented in this paper : selective mapping and comprehensive mapping, in which all biotopes found in the city are surveyed.
125 citations
TL;DR: In this article, the forward electron transfer in intact photosystem I particles from Synechococcus sp. at room temperature has been studied by flash absorption spectroscopy with a time resolution of 5 ns.
TL;DR: The biosynthesis of the lipopeptide antibiotic surfactin was studied in whole cells of Bacillus subtilis ATCC 21332 which incorporate 14C‐labeled precursor amino acids directly into the product.
TL;DR: The number and chemical nature of the electron carrier(s) between Chl aII and the water-oxidizing enzyme, S, were analyzed through flash-induced absorption changes in the UV with nanosecond time resolution as mentioned in this paper.
TL;DR: In this article, a capsule is formed by dropwise addition of a 3% chitosan (polycation) solution into a 0.75% alignate (polyanion) solution.
Abstract: A method has been developed to form capsules with liquid cores where permeability can be modified without sacrificing membrane strength. The capsule is formed by dropwise addition of a 3% chitosan (polycation) solution into a 0.75% alignate (polyanion) solution. The resultant capsule consists of a liquid chitosan core with a hard alginate coating. The addition of CaCl2 to chitosan and glucose to alginate increased capsule strength. The membranes formed were strong enough to require up to 100 Newton during uniaxial compression to burst a 6.4 mm diameter capsule.
TL;DR: Highly active, monomeric and dimeric Photosystem II complexes were purified from the thermophilic cyanobacterium Synechococcus sp.
TL;DR: It is argued that the mental model approach offers a useful perspective for examining how people understand package inserts, and consequently for improving their content and design and promises to be equally useful for other aspects of risk analysis that are dependent upon human judgment and decision making.
Abstract: One way to communicate about the risks of drugs is through the use of package inserts. The problems associated with this medium of informing patients have been investigated by several researchers who found that people require information about drugs they are using, including extensive risk information, and that they are willing to take this information into account in their usage of drugs. But empirical results also show that people easily misinterpret the information given. A conceptual framework is proposed that might be used for better understanding the cognitive processes involved in such a type of risk assessment and communication. It is based on the idea that people develop, through experience, a mental model of how a drug works, which effects it might produce, that contraindications have to be considered, etc. This mental model is "run" when a specific package insert has been read and a specific question arises such as, for example, whether certain symptoms can be explained as normal or whether they require special attention and action. We argue that the mental model approach offers a useful perspective for examining how people understand package inserts, and consequently for improving their content and design. The approach promises to be equally useful for other aspects of risk analysis that are dependent upon human judgment and decision making, e.g., threat diagnosis and human reliability analysis.
TL;DR: In this paper, the conditions for the formation of CH3Cl-hydrate were investigated in mixtures of dimethyl ether and water and the reproducibility of the data with the gE-models was checked.
TL;DR: In this article, it is shown that it is possible to use a bootstrap technique to increase the precession angle and hence the instrument resolution for a given maximum magnetic field intensity in Neutron Resonance Spin Echo (NRSE) spectrometry.
Abstract: We show that it is possible to use a bootstrap technique to increase the precession angle, and hence the instrument resolution for a given maximum magnetic field intensity in Neutron Resonance Spin Echo (NRSE) spectrometry. The limits, theoretical as well as technical, to this effective field amplification are discussed Il est possible d'utiliser la technique du bootstrap pour accroitre l'angle de precision et ainsi la resolution pour un champ magnetique maximal donne en spectrometrie d'echos de spin de neutrons polarises. Discussion des limites theoriques et techniques a l'amplification du champ effectif
TL;DR: In this article, the effects of operating parameters on the ammonium concentration in the acceptor line of the gas-diffusion unit are discussed and experimentally verified on the basis of a simple diffusion model, and several flowinjection methods are examined critically for their suitability for determing submicromolar levels of ammonium ion on a routine basis.
TL;DR: It is shown that the number of induced pre-emptions is proportional to the total number of processing intervals and deadlines, and an O (nm log n) time algorithm is presented to construct such a schedule whenever one exists.
Abstract: Given m semi-identical processors which are parallel processors all working with the same speed but in different time intervals of availability and n independent tasks with deadlines, the problem of constructing a feasible pre-emptive schedule is examined. We present an O (nm log n) time algorithm to construct such a schedule whenever one exists. We show that the number of induced pre-emptions is proportional to the total number of processing intervals and deadlines.
TL;DR: This review is concerned with new directions in deterministic machine scheduling theory, studying resource constrained scheduling, scheduling tasks that require more than one machine at a time, scheduling with nonlinear speed-resource alloted functions, and scheduling in flexible manufacturing systems.
TL;DR: The interpretation of the interelement relationships of (Ta + Nb) and W or (Fe + Mn), Mossbauer spectrometric results on the oxidation state of Fe, and electron probe microanalysis of cassiterites reveal that coupled substitutions of the type 2 (Ta, Nb ) 5+ + ( Fe, Mn ) 2+ = 3 Sn 4+ W 6+ + + 2 Fe 3+ + O 2− are dominant at least at the temperatures of formation in cassiterite.
TL;DR: In this article, the beam quality can be improved without reducing the output power by using several rods inside the same resonator and by a suitable choice of rod position and resonator parameters.
Abstract: Many laser applications require high beam quality at high output power and a broad variation of the output power. The ratio of power variation Delta P/sub out/ to beam parameter product theta /sub m/-w/sub m/ for a single rod inside a stable resonator is a constant which depends on the intrinsic crystal parameters and the slope efficiency only. A broad range of the output power causes a large beam parameter product, i.e. a low beam quality. By using several rods inside the same resonator and by a suitable choice of rod position and resonator parameters, the output power range can be increased without reducing the beam quality. In the same way, the beam quality can be improved without reducing the output power. The details of multirod systems are discussed and compared to experimental results. >
TL;DR: In this article, the effects of chitosans on yield, titratable acidity, pH, soluble solids, and color of carrot and apple juice were evaluated using a cage press.
Abstract: Effects of chitosans on yield, titratable acidity, pH, soluble solids, and color of carrot and apple juice were evaluated. Carrots (Lange Rote Stumpfe) and apples (Golden Delicious) were treated with chitosan solutions (in 2% ascorbic acid) of two different concentrations and viscosities at 25°C between 0 and 120 min. The juices were obtained with a laboratory cage press following a standard program during 20 min. Treatments with chitosan produced no effect on juice yield but pH values and soluble solids were affected. Also chitosan treatment resulted in significant (P < 0.05) reduction of titratable acidity and color index. Reduction of β-carotene in carrot juice was also achieved and correlated with color index.
TL;DR: In this paper, an improved synthesis for Pentaphenylcyclopentadienol (1), pentaphenlycyclpentadienyllithium (4a), and pentaphhenylstannocene (8) is described.
Abstract: Ein verbesserter Syntheseweg fur Pentaphenylcyclopentadienol (1), Pentaphenylcyclopentadienylbromid (2), Pentaphenylcyclopentadien (3), und Pentaphenylcyclopentadienyllithium (4a), die Darstellung von Decaphenylgermanocen (5), -stannocen (6) und -plumbocen (7) sowie von Pentaphenylstannocen (8) wird beschrieben. Die vollstandigen analytische Daten (IR-, Raman-, Rontgenpulver-, NMR-, Massen- und 119mSn-Mosbauer-Spektren) werden angegeben. Es werden 119Sn- und 207Pb-CPMAS-NMR-Messungen von verschiedenen Stannocenen und dem Plumbocen 7 mitgeteilt.
Decaphenylgermanocene, -stannocene, and -plumbocene and Pentaphenylstannocene:Synthesis, Properties, and CPMAS-Metal-NMR Measurements
An improved synthesis is described for pentaphenylcyclopentadienol (1), pentaphenylcyclopentadienyl bromide (2), pentaphenylcyclopentadiene (3), and pentaphenylcyclpentadienyllithium (4a). Decaphenylgermanocene (5), -stannocene (6), and -plumbocene (7) as well as pentaphenylstannocene (8) are prepared. Complete analytical data (IR, Raman, X-ray powder, NMR, mass, and 119mSn-Mosbauer spectra) are given. 119Sn- and 207Pb-CPMAS NMR measurements of various stannocenes and of the plumbocenen 7 are reported for the first time.
TL;DR: Two NADPH-dependent oxidoreductases catalyzing the enantioselective reduction of 3-oxo esters to (S)- and (R)-3-hydroxy acid esters have been purified 121- and 332-fold from cell extracts of Saccharomyces cerevisiae.
Abstract: Two NADPH-dependent oxidoreductases catalyzing the enantioselective reduction of 3-oxo esters to (S)- and (R)-3-hydroxy acid esters, [hereafter called (S)- and (R)-enzymes] have been purified 121- and 332-fold, respectively, from cell extracts of Saccharomyces cerevisiae by means of streptomycin sulfate treatment, Sephadex G-25 filtration, DEAE-Sepharose CL-6B chromatography, Sephadex G-150 filtration, Sepharose 6B filtration and hydroxyapatite chromatography. The relative molecular mass Mr, of the (S)-enzyme was estimated to be 48,000-50,000 on Sephadex G-150 column chromatography and 48,000 on sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The enzyme was most active at pH 6.9 and reduced 3-oxo esters, 4-oxo and 5-oxo acids and esters enantioselectively to (S)- hydroxy compounds in the presence of NADPH. The Km values for ethyl 3-oxobutyrate, ethyl 3-oxohexanoate, 4-oxopentanoic and 5-oxohexanoic acid were determined as 0.9 mM, 5.3 mM, 17.1 mM and 13.1 mM, respectively. The Mr of the (R)-enzyme, estimated by means of column chromatography on Sepharose 6B, was 800,000. Under dissociating conditions of SDS/polyacrylamide gel electrophoresis the enzyme resolved into subunits of Mr 200,000 and 210,000, respectively. The enzyme is optimally active at pH 6.1, catalyzing specifically the reduction of 3-oxo esters to (R)-hydroxy esters, using NADPH for coenzyme. Km values for ethyl 3-oxobutyrate and ethyl 3-oxohexanoate were determined as 17.0 mM and 2.0 mM, respectively. Investigations with purified fatty acid synthase of baker's yeast revealed that the (R)-enzyme was identical with a subunit of this multifunctional complex; intact fatty acid synthase (Mr 2.4 X 10(6)) showed no activity in catalyzing the reduction of 3-oxo esters.
TL;DR: In this article, a method for controlling nonradiative funnels to the ground state in many dyes is proposed to obtain faster saturable absorbers for sub-picosecond laser pulses.
Abstract: TICT states, accessible in twisted multichromophoric systems, are nonradiative funnels to the ground state in many dyes. By controlling these funnels, faster saturable absorbers for subpicosecond laser pulses can be developed. Oriented assemblies of TICT molecules, as in liquid crystalline polymers, are expected to exhibit light-induced macroscopic charge separation. Chemical approaches to supramolecular bistable species are also shown.
01 Dec 1988
TL;DR: A new type of crystals of the reaction center I complex, RC I, of water splitting photosynthesis has been prepared from the cyanobacterium Synechococcus sp. as discussed by the authors.
Abstract: A new type of crystals of the reaction center I complex, RC I, of water splitting photosynthesis has been prepared from the cyanobacterium Synechococcus sp. In contrast to our first crystals (11), the new ones have a length of up to 1 mm, a thickness of up to 50 μm and show X-ray diffraction patterns with a resolution of about 4 A. The space group of the hexagonal crystals is probably P6322. One RC I represents the asymmetric unit. The unit cell dimensions are a = b = 285 A, c = 167 A, α = β = 90° and γ = 120°. The building block of the crystal lattice is a trimer (diameter ˜19 nm, height ˜6 nm, and apparent mass ˜600 kDa). The trimer is composed of 3 identical RC I units so that the quaternary structure is α3. The unit cell harbors four trimers in two layers with two trimers each.
TL;DR: Presented at the 1st international symposium on ferroelectric liquid Crystals, held in 1987 at Archon, Bordeaux.
Abstract: Evidence of a first-order smectic-A--smectic-${C}^{\mathrm{*}}$ (SmA-Sm${C}^{\mathrm{*}}$) transition is presented. Detailed x-ray studies on 4-(3-methyl-2-chloropentanoyloxy)4'-heptyloxybiphenyl show that the SmA-Sm${C}^{\mathrm{*}}$ transition in this material is characterized by a discontinuous jump in the layer spacing (and hence in the tilt angle) and by a narrow two-phase region in which the density modulations due to the smectic-A and the smectic-${C}^{\mathrm{*}}$ phases coexist. Addition of a second compound drives the SmA-Sm${C}^{\mathrm{*}}$ transition towards second order.
TL;DR: Beauvericin synthetase, a multifunctional enzyme catalyzing depsipeptide formation in Beauveria bassiana was purified to near homogeneity and revealed that phenylalanine could be replaced by a number of other aromatic or aliphatic amino acids like beta-phenylserine, ortho-, meta-, para-fluorophenylalanines, isoleucine, norleucine and leucine.
Abstract: Beauvericin synthetase, a multifunctional enzyme catalyzing depsipeptide formation in Beauveria bassiana was purified to near homogeneity. The enzyme consists of a single polypeptide chain with a molecular mass of about 250 kdaltons. The mechanism of beauvericin formation is very similar to that of the cyclohexadepsipeptide enniatin. The constituents of the beauvericin molecule, L-phenylalanine and D-alpha-hydroxyisovaleric acid are activated as thioesters via the corresponding adenylates. N-Methylation takes place at the thioester bound stage of the phenylalanine residues. Omission of the methyl donor S-adenosyl-L-methionine results in the formation of demethylbeauvericin. Studies on substrate specificity revealed that phenylalanine could be replaced by a number of other aromatic or aliphatic amino acids like beta-phenylserine, ortho-, meta-, para-fluorophenylalanine, isoleucine, norleucine and leucine. Valine, the constituent amino acid of enniatin B was not accepted by the enzyme.