Showing papers by "University of Cologne published in 1973"
TL;DR: In this article, secondary ion mass spectroscopy (SIMS) was used to investigate the chemical composition of the uppermost monomolecular layer of the bombarded surface.
402 citations
TL;DR: The Davson-Danielli-Robertson-Benson-Singer membrane model, which assumes a fluid lipid bilayer with “integral” proteins embedded in the lipid matrix and surface proteins attached to the lipid head groups, appears to have an halo in which the chain-chain interaction between the lipids is disturbed.
261 citations
153 citations
TL;DR: In this article, the main poles of one-particle Green's functions in the low-energy region and their pole strengths for the molecules F2, H2O, C2H2 and H2CO were calculated.
Abstract: A theory recently developed for atoms and molecules is applied to the calculation of the main poles of one-particle Green's functions in the low-energy region and their pole strengths for the molecules F2, H2O, C2H2 and H2CO. The poles corresponding to occupied orbitals compare well with the experimental vertical ionization potentials (VIP's). In particular the sequence of the VIP's of F2 which is not reproduced by Koopmans' theorem (breakdown) is re-established. The corresponding pole strengths are found to have values around 0·9.
146 citations
TL;DR: Both IS1 and IS2 are also found in the DNA of the F plasmid, both of which have been detected by DNA-DNA hybridization in the chromosome of E. coli K-12.
Abstract: About 8 copies of the DNA sequence IS1 (which consists of 800 nucleotide pairs) and about 5 copies of the DNA sequence IS2 (1400 nucleotide pairs) have been detected by DNA-DNA hybridization in the chromosome of E. coli K-12. No homology is observed between IS1 and IS2. Both IS1 and IS2 are also found in the DNA of the F plasmid.
122 citations
TL;DR: The inheritance of idiotypes was investigated using idiotypic antisera against two monoclonal antibodies to streptococcal carbohydrates derived from A/J mice to suggest that idiotypes are specified by allelic V genes, and that theheavy chain idiotype locus is linked to the heavy chain allotype locus.
Abstract: The inheritance of idiotypes was investigated using idiotypic antisera against two monoclonal antibodies to streptococcal carbohydrates derived from A/J mice. Each of the two idiotypes was characterized by a special frequency of expression. One of the idiotypes was expressed in more than 80% of A/J mice, the other in less than 20%. The idiotypes of both antibodies were strain specific and were transmitted to (A/J x BALB/cJ)F1 hybrid mice. Furthermore, both idiotypes remained associated with the A/J heavy chain C region allotype in (A/J x BALB/cJ)F1 hybrid mice. The results suggest that idiotypes are specified by allelic V genes, and that the heavy chain idiotype locus is linked to the heavy chain allotype locus.
109 citations
TL;DR: In this paper, N-Methyl-bis and bis (trifluoroacetamide) are used as reagents for selective acylation of amine functions in the presence of hydroxyl or carboxyl groups.
80 citations
TL;DR: In the haemolymph of adult female locusts six different lipoprotein fractions have been demonstrated by means of isoelectric focusing, and one of these binds injected 3 H-Cecropia juvenile hormone.
79 citations
TL;DR: The results suggest that a complex of citrate and Mg2+ is the transported substrate, which does function normally in a Co2+-resistant mutant of B. subtilis and may be stoichiometrically reduced by limiting the concentrations of Mg 2+.
70 citations
TL;DR: In this article, the splitting pattern observed for the 13 C NMR signals in the 1 H-undecoupled spectra of symmetrically ortho-disubstituted benzenes differs characteristically for carbons in the position α and β to the substituted carbons, thus, giving rise to typical fingerprints.
67 citations
TL;DR: In this paper, the current induced phase transition from the superconducting to the normalconducting state was studied in whiskers of tin, and the influence of a magnetic field on the location and the structure of the curves was measured and compared to theoretical predictions.
Abstract: The current induced phase transition from the superconducting to the normalconducting state is studied in whiskers of tin. Transition curves were taken byU(T)-measurements at steady currents as well as characteristic curves byU (I)-measurements at fixed temperatures. For larger current intensities these curves show voltage steps which increase linearly with current intensity. The onset of voltage reading appears at the critical current density, as predicted by theory. The step structures are, however, observed at current densities which are several times larger than the critical ones. The influence of a magnetic field on the location and the structure of the curves was measured and is compared to theoretical predictions. At temperatures close toTco whiskers are onedimensional with respect to the superconducting orderparameter because of their small diameters. Therefore, intermediate state pattern and flux flow are rejected as an explanation of the observed structures.
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01 Jan 1973TL;DR: Combined biotyping and serotyping is suggested for subdivision of the P. acnes species after thoroughly examined both biochemically and serologically.
Abstract: Seventy-two Propionibacterium acnes strains, among which were five from the American Type Culture Collection, five from the Center for Disease Control, and four of group II of Voss, were thoroughly examined both biochemically and serologically. On the basis of the fermentation of inositol, maltose, mannitol, and sorbitol, eight biotypes were distinguished. By means of tube agglutination tests with the five absorbed antisera, 95, C51, D34, S140, and Beck, 11 serotypes were defined. The biotypes and serotypes showed no striking relationship to each other. Combined biotyping and serotyping is suggested for subdivision of the P. acnes species.
TL;DR: Replication of the E. coli chromosome, studied by the sequential mutagenesis method in synchronized cells, is shown to be bidirectional with an origin close to the ilv marker and a terminus between the trp and his markers.
Abstract: Replication of the E. coli chromosome, studied by the sequential mutagenesis method in synchronized cells, is shown to be bidirectional with an origin close to the ilv marker and a terminus between the trp and his markers.
TL;DR: In both fundamental and applied surface physics, it is essential to know as much as possible about the chemical composition of the outer atomic layers of solids as discussed by the authors, and rapid progress has recently been made in the development of analytical methods which could be used in surface analysis.
Abstract: In both fundamental and applied surface physics, it is essential to know as much as possible about the chemical composition of the outer atomic layers of solids. Rapid progress has recently been made in the development of analytical methods which could be used in surface analysis. All utilize some type of emission (photons, electrons, atoms, molecules, ions), caused by excitation of the surface states. Both the “excitation” and emission processes must meet certain basic requirements as regards information depth, form in which the information is obtained, sensitivity, changes in the surface layer during analysis, etc. The more important of the methods that qualify, namely Auger-Electron Spectroscopy (AES), photo-Electron Spectroscopy for Chemical Analysis (ESCA) and the static method of Secondary-Ion Mass Spectrometry (SIMS), are discussed and their potentialities and limitations illustrated by characteristic examples.
TL;DR: In this article, a single mode cw dye laser was used to investigate the hyperfine splittings of the Na D1 and D2 lines of a Na D2 line, where the light of the laser was scattered by the atoms of an atomic beam.
Abstract: The hyperfine splittings of the Na D1 and D2 lines were investigated using a single mode cw dye laser. The light of the laser was scattered by the atoms of an atomic beam and the fluorescent light was observed as the frequency of the laser was tuned across the D lines. The Doppler width of the atomic beam was reduced to about 2.5 MHz so that the absorption width of the atoms of the beam was essentially determined by the natural width of the 32P1/2 and 32P3/2 levels, which is about 10 MHz. Since the linewidth observed for the hyperfine transitions was 30 MHz, most of the hyperfine components of the D1 and D2 lines could be resolved. In another experiment the frequency of the dye laser was locked to a hyperfine transition of the D1 line. The observed variation of the output frequency of the dye laser was less than ±1.5 MHz. In addition, the intensity of the dye laser was controlled to about 10−3, using an electro-optically variable transmission filter.
TL;DR: In those cases where definite conclusions regarding the mechanism can be drawn, catalysis seems to occur by a carboxylate ion as base and an acid that has been identified as a car boxyl group withβ-glucosidase from Asp.
Abstract: A review is given on the inactivation of glycosidases by active site directed inhibitors, their use to identify functional groups at the active site, and deductions with respect to the mechanism of catalysis. The following enzymes are discussed:β-glucosidases from various sources,α-glucosidase from S. cerevisiae,β-galactosidases from E. coli and Helix pomatia, cellulase and lysozyme. Epoxide type inhibitors appear especially suitable because their reactivity is enhanced selectively by acidic groups at the active site.
TL;DR: The performance of the Ampholytes prepared employing the more highly substituted ethylene amines was found to be comparable to that of the commercial ampholytes over the pH range 4 to 8.
TL;DR: An 6 Beckenhalften wurde die Dichteverteilung in der Huftpfanne untersucht as mentioned in this paper, i.e., the Dichteminimum am Boden der Fossa acetabuli gefunden, jedoch ein Anstieg zur Incisura acetabili hin.
Abstract: An 6 Beckenhalften wurde die Dichteverteilung in der Huftpfanne untersucht. Die groste Dichte liegt am auseren Rand der Facies lunata, zum inneren Rand hin nimmt die Dichte ab. Bei einem jugendlichen Objekt wurde eine erheblich geringere Dichte im Pfannendach festgestellt. Bei allen Objekten wurde ein Dichteminimum am Boden der Fossa acetabuli gefunden, jedoch ein Anstieg zur Incisura acetabuli hin. Die Befunde werden in Beziehung zur Lage der Resultierenden im Huftgelenk gesetzt; sie deuten auf eine exzentrische Beanspruchung der knochernen Huftpfanne hin. Es wird diskutiert, ob diese Beanspruchung durch exzentrische Lage der Huftgelenksresultierenden verursacht wird, oder aber die Folge einer in der Literatur beschriebenen funktionsbedingten Knorpelquellung ist. Fur das jugendliche Objekt kann die Dichteabnahme im Pfannendach durch eine Inkongruenz der Gelenkflachen des Huftgelenks wahrscheinlich gemacht werden.
TL;DR: In this paper, the electrical resistivity of the Kondo system ( La, Ce)Al2 has been measured in longitudinal magnetic fields to 50 kOe in the temperature range 0.05-20 K. The data cannot be explained by existing perturbation theory.
TL;DR: It seems reasonable to suggest that contact zones rather than free axonal endings are the main pathways for skin innervation.
TL;DR: In this article, the temperature dependence of the pair-breaking parameter has been deduced empirically from the upper critical field curves, assuming additive pair breaking theory, and the transition back into the normal state has been observed by means of dc-conductivity and low frequency mutual inductance measurements down to 30 mK.
Abstract: In the ternary alloy (La, Ce)Al2 the Kondo anomalies due to the Cerium impurities are studied in the normal and superconducting state. A vanishing of superconductivity in certain (La, Ce)Al2 alloys below a second transition temperature has been observed for the narrow range of 0.6–0.7 at% Ce-additions. The transition back into the normal state has been observed by means of dc-conductivity and low frequency mutual inductance measurements down to 30 mK. Curves of the upper critical field versus temperature show a maximum at finite temperatures even for lower Ce-concentrations. The temperature dependence of the pair-breaking parameter has been deduced empirically from the upper critical field curves, assuming additive pair breaking theory. In contradiction to the theory no decrease of the pair-breaking parameter forT → 0 can be observed. Therefore the reentrance of superconductivity at ultra low temperatures cannot be expected.
TL;DR: The results may support the hypothesis that the effect of cold on platelets is due to conformational changes of the membrane proteins.
TL;DR: It is suggested that these rules, which pertain to a system of classification based primarily upon complementation analysis, also be applied to mutants of other DNA-containing animal viruses.
Abstract: In accord with the nomenclature proposed for mutants of simian virus 40 the same rules, with minor modifications, are recommended for naming mutants of adenoviruses. It is further suggested that these rules, which pertain to a system of classification based primarily upon complementation analysis, also be applied to mutants of other DNA-containing animal viruses.
TL;DR: In this paper, the average value of these matrix elements is about 100 keV and no significant difference in the average values of the off-diagonal matrix elements was found for the different spin values.
TL;DR: Tissue-cultured Aedes albopictus cells infected with morphologically homogeneous Sindbis virus were found to produce progeny virions which could be divided into three classes based on size, suggested that the three classes of virions have icosahedral nucleocapsids composed of common subunits organized in decreasing triangulation numbers.
Abstract: Tissue-cultured Aedes albopictus cells infected with morphologically homogeneous Sindbis virus were found to produce progeny virions which could be divided into three classes based on size. The thickness of the envelope was constant on all three sizes of progeny virions suggesting that the variability in size rested with the viral nucleocapsid. It is suggested that the three classes of virions have icosahedral nucleocapsids composed of common subunits organized in decreasing triangulation numbers.
TL;DR: A comparison reveals that during cold shivering the activity of the dynamic fusimotor system increases and theActivity of the static fusIMotor system decreases.
Abstract: 1.
Primary and secondary muscle spindle endings and Golgi tendon organs from the gastrocnemius muscle of the cat were investigated before, during and after a cold shivering of the animals. The discharge patterns of the proprioceptors were recorded during a ramp stretch of the muscle. The stretch length was varied from 4 to 14 mm, the stretch rate from 30 to 350 mm/sec.
2.
The static, dynamic, and acceleration responses were determined before and during cold shivering tremor and plotted against the corresponding stretch parameters (length, velocity, or acceleration). These curves are called “characteristic curves” and their slopes characterize the “senitivities” of a receptor. During shivering sensitivity changes, i.e. changes of the curves' slope, were observed.
3.
During cold shivering the velocity and acceleration sensitivities of the primary endings decrease. Their length sensitivity exhibits a non-uniform behavior. The secondary endings slightly minimize their length sensitivity during shivering but the velocity and accelaration sensitivities remain unchanged. The three sensitivities of the Golgi tendon organs, too, remain unchanged.
4.
The changes that occur in the discharge patterns during cold shivering are compared with the changes that are caused by artificial fusimotor stimulations. This comparison reveals that during cold shivering the activity of the dynamic fusimotor system increases and the activity of the static fusimotor system decreases.
5.
The fusimotor innervations that are observed by other authors during the different tremor states are compared with the present data.
TL;DR: The segmentally arranged somata of the dorsal giant fibres in the ventral nerve cord of the earthworms Lumbricus terrestris L., is described and these neurones are compared with other neurones of invertebrates and vertebrates.
Abstract: Die proximalen Kollateralen der dorsalen Riesenfasern des Regenwurms wurden in Serienschnitten vom Soma bis zum Eintritt in die Riesenfaser verfolgt und im Hinblick auf ihre Feinstruktur und ihre synaptischen Kontakte Untersucht. Es finden sich sowohl chemische als auch elektrische Synapsen. Ihre Feinstruktur wird mit der bekannter Synapsen anderer Wirbellosen und Wirbeltiere verglichen. In beiden Riesenfasersystemen kommen efferente chemische Synapsen mit feinen postsynaptischen Verzweigungen vor, die anscheinend von Bauchmark-Motoneuronen stammen. Das Axon der medianen Riesenfaser weist daruber hinaus nur noch eine elektrische Synapse mit den Rieseninterneuronen auf. Demgegenuber erhalten die Kollateralen der lateralen Riesenfasern zahlreiche Afferenzen, die zum Teil als sensorische Fasern der Epidermis, multisegmentale Fasern der Hauptfaserzuge und Rieseninterneurone identifiziert werden konnten. Weitere Afferenzen stammen vermutlich von unisegmentalen Interneuronen her. Beide lateralen Riesenzellaxone bilden auserdem miteinander eine elektrische Chiasma-Synapse mit besonderen Membraneinfaltungen.
TL;DR: The purpose of this study was to check the possibilities of differentiating coagulase-negative staphylococci with the help of biochemical and morphological characteristics, and an intermediate group between these two genera was proposed and described.
Abstract: The purpose of our study was to check the possibilities of differentiating coagulase-negative staphylococci with the help of biochemical and morphological characteristics. Altogether 59 reactions were examined on a material of 147 strains, which were isolated from human pathogenic processes in USA, Canada, Denmark, CSSR and Germany.