Showing papers by "Humboldt University of Berlin published in 1981"
TL;DR: In this article, the authors discuss the renormalization of the contour-dependent gauge-invariant composite bilocal or string operator q (2) exp |g ∫ 1 2 A d z|q(1) in QCD, which one would naturally associated with the hadronic bound states.
106 citations
TL;DR: In this article, the authors elucidate the following facts and problems of Tertiary Forest vegetation in Europe: 1. The Paleotropical Geoflora: Evolution centre in Europe or floral belt.
80 citations
TL;DR: The molecular activity of the haemoglobin-catalyzed oxygenation of linoleate was comparable with those of true lipoxygenases and was strongly suppressed by denaturation (heating, urea, pronase treatment, acid splitting); the apparent S0.5, the activation energy and the pH-optimum did not differ from those of most of the true lip Oxygenases.
Abstract: Haemoglobin catalyses at low concentrations (0.01–1 μM) a quasi-lipoxygenase reaction with remarkably high substrate specificity. Formation of lipohydroperoxides was demonstrated only with free 9-cis,12-cis-octadecadienoic acid (Linoleic acid), its glycerol monoester, or 9-cis,12-cis-octadecadienol (Linoleoyl alcohol). All-cis,-9,12, 15-octadecatrienoic acid (α-linolenic acid), all-cis,-5,8,11,14-eicosatetraenoic acid (arachidonic acid) and all-cis,-9,12, 15- eicosatetraenoic acid (dihomo-ν-linolenic acid), phospholipids and biological membranes were not attacked. Saturated and unsaturated free fatty acids other than linoleic acid were strong inhibitors of the haemoglobin-catalyzed oxygenation of linoleate. The reaction was also inhibited by cyanide, carbon monoxide, phenolic antioxidants and the lipoxygenase inhibitor salicylhydroxamic acid, as well as by some anti-inflammatory drugs (prednisolone, dexamethasone, acetylsalicylic acid); indomethacin did not inhibit. Protein inhibitors of liproxygenase reactions were found in lung homogenates of various species. The molecular activity of the haemoglobin-catalyzed oxygenation of linoleate was comparable with those of true lipoxygenases and was strongly suppressed by denaturation (heating, urea, pronase treatment, acid splitting). The apparent S0.5, the activation energy and the pH-optimum did not differ from those of most of the true lipoxygenases.
The reaction product hydroperoxylinoleic acid but not hydrogen peroxide was an activator of the haemoglobin-catalyzed oxygenation of linoleate. Hydroxylinoleic acid was a competitive inhibitor of the activation. At haemoglobin concentrations higher than 1 μM the quasi-lipoxygenase activity was completely suppressed presumably owing to the formation of inhibitory concentrations of hydroxylinoleate via the lipohydroperoxidase [21] activity of haemoglobin.
The quasi-lipoxygenase reaction of haemoglobin exhibits a suicidal behaviour, caused by destruction of haem groups. The properties of the free haemin-catalyzed reaction were similar to those of haemoglobin. Among other haemoproteins tested myoglobin and cytochrome P-450LM show comparable activities. The mechanism of the haemoglobin-catalyzed oxygenation of linoleate seems to involve a change of valency of the haem iron.
53 citations
TL;DR: The effect of the adaptation period, age and length of test are discussed with particular reference to the role of the feeding system in relation to the correlated responses of selection for growth rate.
47 citations
TL;DR: In this article, the rectal body cooling by corrective factors of the body weight was used to estimate the time of death of a dead body, and the permissible variation of 95% resp.
Abstract: Cooling conditions differing from the chosen standard (naked-resting air) of storing of a dead body may be proportionally adjusted in computing of the time of death by data of the rectal body cooling by corrective factors of the body weight. These differing cooling conditions are: permanently moved air-clothing-covering-wet clothing. In our experiments the corrective factors of the body-weight range from 0.7 for totally wet clothing + permanently moved air to 2.4 for a covering similar to bed clothes. Temperature-time of death-relating nomogrammes, easily to handle, replace the computing without losing accuracy. The permissible variation of 95% resp. 99% in estimating the range of the time of death was found out.
40 citations
TL;DR: An attempt was made to interpret the variations in the course of the facial nerve and certain forms of stapes and incus malformation on the basis of the developmental processes in the area of the skull base and of the brain.
Abstract: Analysis of the information obtained from more than 110 malformations of the external and middle ear operated upon by the author (Gerhardt) leads to speculation as to their course of development. Of particular interest are the varying types of stapes malformations and the influence of variations in the course of the facial nerve on the development and shaping of the stapes. In the light of clinical examples, an attempt was made to interpret the variations in the course of the facial nerve and certain forms of stapes and incus malformation on the basis of the developmental processes in the area of the skull base and of the brain.
39 citations
Journal Article•
38 citations
TL;DR: Non-ionic detergents such as polyoxyethylene-octylphenol or -sorbitolester were found to increase activity of horseradish peroxidase due to delay of inactivation in the course of substrate reaction, and in enzyme-immunoassay, detection limit and analytical sensitivity can be doubled.
33 citations
31 Aug 1981
TL;DR: By giving a matrix inversion algorithm that uses a small amount of space, a result of Simon is improved: For constructible functions f(n)∉ o(logn) f( n) tape-bounded probabilistic Turing machines can be simulated on deterministic ones within (f(n))2 space.
Abstract: By giving a matrix inversion algorithm that uses a small amount of space, a result of Simon is improved: For constructible functions f(n)∉ o(logn) f(n) tape-bounded probabilistic Turing machines can be simulated on deterministic ones within (f(n))2 space.
32 citations
TL;DR: In this article, a closed system of equations for the nonequilibrium pair-distribution function is given which corresponds to the mean spherical approximation (MSA) in equilibrium, and the electrophoretic contribution to the conductance is calculated exactly in the framework of the MSA.
Abstract: A closed system of equations for the nonequilibrium pair-distribution function is given which corresponds to the mean spherical approximation (MSA) in equilibrium The electrophoretic contribution to the conductance is calculated exactly in the framework of the MSA For the calculation of the remaining contributions the equilibrium distribution function due to Henderson and Smith was used The final expressions for the conductance are given in analytic terms using the restricted primitive model The calculated curves are in good agreement with experimental data for 1-1 electrolytes up to about 1 M and qualitatively show the right behaviour up to rather high concentrations
TL;DR: The Fe-S clusters of the mitochondrial outer membrane are destroyed by lipoxygenase treatment, without any effect on the rotenone-insensitive NADH: cytochrome c oxidoreductase activity.
TL;DR: This study presents a survey of the textural forms of calcium oxalate calculi, which has classified this texture into four basic types and the transformation mechanism of weddellite into whewellite is discussed at length.
Abstract: This study presents a survey of the textural forms of calcium oxalate calculi. We have classified this texture into four basic types. The transformation mechanism of weddellite into whewellite is discussed at length. According to our investigations there are two ways of formation of whewellite calculi: 1. primary formation of whewellite, and 2. secondary formation by way of weddellite transformation.
TL;DR: In this article, the authors examined 6 lakes in the German Democratic Republic (GDR) during water blooms and examined for their toxicity to homothermal animals, including Microcystis aeruginosa, Aphanizomenon flos-aquae, Anabaena spiroides, and Oscillatoria redekei.
Abstract: From 1977 to 1979 plankton samples were taken from 6 lakes in the German Democratic Republic (GDR) during water blooms and examined for their toxicity to homothermal animals. Microcystis aeruginosa, Aphanizomenon flos-aquae, Anabaena spiroides, and Oscillatoria redekei were dominant in the samples. With the exception of Oscillatoria redekei the algae tested had toxic effects on mice after intraperitoneal injection. The rate of survival of the test animals was particularly low when the algae were disintegrated by ultrasound or freeze-drying prior to injection, this indicating the endogenic character of the toxins. Water blooms of Microcystis aeruginosa taken from Lake Pehlitzsee (Eberswalde District) showed the highest toxicity with an LD30 as high as 45 and 43.7 mg/kg, respectively. Injection of the lyophilized cells of Aphanizomenon flos-aquae brought about the same symptoms in the test animals as in the case of Microcystis, but the LD30 was 200 mg/kg.
TL;DR: Using a Gaussian approximation for the depth distribution of the energy dissipation function for electron bombardment, the electron beam induced barrier current (BC) was determined as a function of the position on a surface perpendicular to the barrier.
Abstract: Using a Gaussian approximation for the depth distribution of the energy dissipation function for electron bombardment, the electron beam induced barrier current (BC) is determined as a function of the position on a surface perpendicular to the barrier. Comparison of theory and experiment for the energy and position dependence of BC provided values for the diffusion length and the surface recombination velocity of excess carriers. The experiments are performed in a wide range of diffusion lengths and dopand concentration on Si and GaP for primary energies of electrons between 10 and 30 keV. The parameters for the Gaussian depth distribution are estimated for Si and GaP and compared with values taken from the literature.
TL;DR: The studies admit the conclusion that physical training and chronic altitude hypoxia in the left heart result in different structural patterns which correspond to different responses of the contractile function.
Abstract: Summary Comparative ultrastructural morphometric and physiological studies of the left ventricle of the rat were made with the aim to obtain information on the adaptation process of the rat heart to physical training and high altitude. For this purpose animals were subjected to mild swimming exercise (up to 1 hour per day for a total duration of 40 hours), a second group was subjected to hypoxia in a hypobaric chamber (6,000 m, 5 hours per day). The ultrastructural examinations were carried out in accordance with stereological principles using the conventional point counting technique, whilst examinations of the contraction function were performed on the isolated papillary muscle. Physical training leads to a left ventricular hypertrophy with a significant increase in wet weight by 21%. Morphometric analysis of myocardial cells showed an increase in the volume density of mitochondria, which is attributed to an increase in their number. There is an increase in the surface density of the sarcoplasmic reticulum (SR). The surface density of the SR per unit volume of myofibrils (SR/myofibrils ratio) is enlarged by 55%. The Golgi apparatus shows pronounced hyperplasia. Hypoxia results in a slight left ventricular hypertrophy, which is only 50% of that of the right ventricle. The mitochondria are enlarged, but diminished in number, so that their volume density remains constant. The SR/myofibrils ratio is enlarged only by 8%. Hyperplasia of the Golgi apparatus is slight. Unlike in the case of exercised animals, the T-tubuli are reduced in number and dilated. In comparison with the non-adapted animals, most parameters of the contractile function of the myocardium conditioned through exercise are significantly increased, but no such increase is observed in the case of altitude hypoxia. The changes in the cardiac contractile function observed after adaptation to physical training are based on biogenesis of mitochondria and on structural changes of the SR. The increased relaxation velocity after physical training could, for instance, be attributed to the significant increase in the SR/ myofibrils ratio. The studies admit the conclusion that physical training and chronic altitude hypoxia in the left heart result in different structural patterns which correspond to different responses of the contractile function. These findings can be explained by differences in the cell's adaptation mechanism, the phosphorylation potential probably being a key factor in the biogenesis of cellular structures.
TL;DR: In this paper, a weakly interacting system of electrons (e) and ions (i) is considered and Pade-approximations for the thermodynamic functions are constructed which are valid in the entire temperature-density plane.
Abstract: A weakly interacting system of electrons (e) and ions (i) is considered. Based on analytical formulae in the limiting regions of both weak and strong degeneration of the e4-contribution and a few computer calculated points in the intermediate region n Λ3 ≈ 1 (n electron density, Λ thermal wavelength, Λ2 = 2πβh2/me, β = (kBT)−1, me electron mass) Pade-approximations for the thermodynamic functions are constructed which are valid in the entire temperature–density plane. The temperature dependence of the exchange and correlation contribution to the chemical potential is taken into account here for the first time. In the framework of an unsymmetrical electron–hole model of germanium, a phase transition occurs with a critical point at Tc = 8 K and nc = 1.0 × 1017 cm−3.
Es wird ein schwach wechselwirkendes System aus Elektronen (e) und Ionen (i) betrachtet. Mit bekannten analytischen Formeln in den Grenzgebieten schwacher und starker Entartung fur den e4-Beitrag und computerberechneten Punkten im Zwischenbereich (n ≈ 1) werden Pade-Approximationen fur die thermodynamischen Funktionen konstruiert, die in der gesamten Temperatur-Dichte-Ebene gultig sind. Erstmals wird der Austausch- und Korrelationsbeitrag zum chemischen Potential temperaturabhangig berechnet. Im Rahmen eines unsymmetrischen Elektron-Loch-Modells des Germaniums wird ein Phasenubergang mit der kritischen Temperatur Tc = 8 K und der kritischen Dichte nc = 1,0 × 1017 cm−3 erhalten.
TL;DR: Cytophotometric and spectrophotometric determinations of the phycoerythrine and phycocyanine contents of different strains after exposure to blue-green and orange-red light suggested that chromatic adaptation of O. redekei takes place both at cellular and population level.
Abstract: Natural populations and culture strains of Oscillatoria redekei isolated from the same lakes exhibit a great variety of phycoerythrine/phycocyanine ratios even under the same growth conditions. Cytophotometric and spectrophotometric determinations of the phycoerythrine and phycocyanine contents of different strains after exposure to blue-green and orange-red light, respectively, suggested that chromatic adaptation of O. redekei takes place both at cellular and population level. This wide intraspecific diversity is considered at least one reason for competitiveness in highly eutrophic lakes.
TL;DR: In this paper, a short summary is given about the history of formgroup and related genera of the subfamily Juglandoideae, which contributes to a better understanding of the distribution pattern and ecological attitudes.
Abstract: Von 14 Arten glattschaliger Nusse der Gattung Carya Nutt. sect. Pacania (Raf.) Rehd. werden genaue morphologische Beschreibungen, Bestimmungsschlussel und Abbildungen der Holotypen einiger fossiler Arten gegeben. Sieben fossile Arten in Europa gehoren in die nahere Verwandschaft des Formenkreises der Vietnam-Nus (Carya poilanei (Chev.) Leroy. Sie treten vom Eozan bis Pliozan auf und belegen eine reiche Entwicklung des gegenwartig disjunkt ostasiatisch — nord- bis mittelamerikanisch verbreiteten Formenkreises in den tertiaren Mixed Mesophytic Forests des europaischen Teilareales. Ein kurzer Abris der Geschichte des Formenkreises und ihrer Verwandten aus der Unterfamilie der Juglandoideae auf der Nordhemisphare fuhrt zum Verstandnis des heutigen Verbreitungsmusters und des okologischen Verhaltens.
Precise descriptions, determination-keys, and copies of some fossil holotypes of 14 species of the genus Carya Nutt. sect. Pacania (Raf.) Rehd. with smooth nuts are given. Seven fossil species in Europe show closer relationship to the formgroup of Vietnamese nut (Carya poilanei (Chev.) Leroy). They exist in the Tertiary Mixed Mesophytic Forests from Eocene till Pliocene and demonstrate a rich development of this formgroup in the European part of area, which is actually of an East-Asian-North-Centralamerica disjunct distribution. A short summary is given about the history of formgroup and related genera of the subfamily Juglandoideae. It contributs to a better understanding of the distribution-pattern and ecological attitudes.
TL;DR: It is shown that the precursor to human placental lactogen is bound to rough ER membranes from dog pancreas as is carp preproinsulin and the binding sites determined post-translationally are identical with the signal peptide receptors functioning during vectorial transport of the nascent chain.
TL;DR: In this article, the least bound core levels of cations and anions of cubic ANB8−N semiconductors were calculated by means of an electrostatic model with ionic and bond charges according to Phillips' bond charge model.
Abstract: Core electron binding energies EB with respect to the vacuum level and their chemical shifts are calculated for the least bound core levels of cations and anions of cubic ANB8−N semiconductors. Starting from the HF-binding energy of the free atom absolute values of EB are obtained by adding core level shifts and relaxation energies. Core level shifts are calculated by means of an electro-static model with ionic and bond charges according to Phillips' bond charge model. For the calculation of relaxation energies the linear dielectric theory of electronic polarization is applied. Valence and core electrons, and diagonal and non-diagonal screening are taken into account. The theoretical results for chemical shifts of binding energies are compared with experimental values from XPS-measurements corrected by work function data. Good agreement is obtained in all cases within the error limit of about one eV. Chemical and atomic trends of core level shifts, relaxation energies, and binding energies are discussed in terms of changes of atomic and solid state parameters. Chemical shifts and relaxation energies are predicted for various ternary ANB8−N compounds.
TL;DR: Aspartate aminotransferase determinations in erythrocytes of patients undergoing chronic haemodialysis and with kidney transplants showed that patients receiving vitamin B6 had a smaller relative stimulation rate of AST by pyridoxal-5'-phosphate (P-5-P).
TL;DR: The study is mainly based on herbarium specimens and includes 20 Eurasian species that are more or less xerophytic that are mainly distributed in South Europe and Southwest Asia, especially in Turkey.
Abstract: Zur Sect. Lathyrostylis der Gattung Lathyrus gehoren 20 eurasische, ± xerophile Arten. Sie sind hauptsachlich in Sudeuropa und Sudwestasien, besonders in der Turkei, verbreitet. Die Mehrzahl der Arten bewohnt Trocken- oder Steppenrasen, Gebuschsaume, lichte Kiefernwalder, Macchien, Felshange und Gerollhalden. Die Sektion wird durch folgende wesentliche Merkmale charakterisiert: Alle Arten sind ausdauernd. Die (1–)2–(3)–8)paarig gefiederten, amphistomatischen Blatter sind stets rankenlos und die Narvatur der Fiederblattchen ist regelmasig parallelnervig. Der Griffel ist nicht gedreht und bei einzelnen Arten an der Spitze spatelformig verbreitert. Subsektionen oder Series konnen nicht unter-schieden werden. Die Untersuchungen stutzen sich vor allem auf Herbarmaterial. Nur wenige Arten konnten kultiviert werden. Ein Bestimmungsschlussel enthalt die Arten und Unterarten. Die Arealkarten wurden vor allem nach revidierten Herbarbelegen angefertigt. Die Arten und infraspezifischen Taxa werden beschrieben und ihre Variabilitat, verwandtschaftlichen Beziehungen, geographische Verbreitung und Okologie erortert. Schlieslich werden einige Erganzungen und Berichtigungen zur Revision von Lathyrus sect. Orobus (Bassler 1973) dargestellt.
Lathyrus sect. Lathyrostylis includes 20 Eurasian species that are more or less xerophytic. They are mainly distributed in South Europe and Southwest Asia, especially in Turkey. The majority of the species inhabits dry meadows, scrubs, Pinus forests, macchies, rocky slopes and screes. The following diagnostic characters are valuable: All species are perennial. The pinnate leaves consist of (1–)2–3(–8) pairs of parallelveined, amphistomatic leaflets and the rachis ending in a simple tip. The style is linear to broadly spathulate but not twisted. Within the section neither subsections nor series can be distinguished. The study is mainly based on herbarium specimens. Only few species had been cultivated. A key to species and subspecies and new maps, mainly based on revised herbarium specimens, are given. Species and infraspecific taxa are described, and their variability, relationships, phytogeography and ecology are discussed. At last some supplements and corrections to the revision of Lathyrus sect. Orobus (Bassler 1973) are added.
TL;DR: In this article, the kinetic and thermodynamic values of the reversible photodimerization of 17 endo-and exocyclic substituted anthracenes are presented and discussed on the basis of the potential correlation diagram.
Abstract: Deactivation Behaviour of Arenes and Heteroarenes. XXXII. The Influence of Endo- and Exocyclic Substitution on the Reversible Dimerization Behaviour of Anthracenes
The kinetic and thermodynamic values of the reversible photodimerization of 17 endo- and exocyclic substituted anthracenes are presented and discussed on the basis of the potential correlation diagram. The deactivation kinetics of the partial steps of photodimerization (excimer formation, transition into the pericyclic state, dimer formation) is influenced in dependence on the type and the place of substitution. From the determined partial values the interpretation of the integral behaviour is possible.
A relationship between the enthalpy of dimer formation, thermal stability and quantum yield of dimer formation is obtained. The sum of the quantum yields of forward and back reaction is 1 with the exception of derivatives substituted by heavy atoms and in the case of fluorescent excimers, respectively. With that the model of the common pericyclic transition state is confirmed.
TL;DR: In this paper, the authors analyzed the selection processes within a population of a high number of self-reproducing species by use of the generating function method and derived the steady state values of the mean numbers of individuals for all species by solving a linear difference equation.
TL;DR: In this article, the classical collision theory for two moving charged particles was used to calculate the electronic stopping power for incident ions, and it was shown that in the energy region, where the stopping power is maximized, motion of the target electrons must be considered.
TL;DR: In this paper, the derivation of string type equations from QCD is reexamined in the framework of renormalized perturbation theory, and the reduction of the equation to a linear one of string-type can be understood.
Abstract: The derivation of string type equations from QCD is reexamined in the framework of renormalized perturbation theory. Renormalizing the equation for the second functional derivative of the Wilson functional at different points one observes a short distance problem which is studied by the help of OPE and RG. On this line the reduction of the equation to a linear one of string-type can be understood.