Showing papers by "Goethe University Frankfurt published in 1978"

A field study on the dependence of the fecundity of Daphnia spec. on food concentration.

Abstract: The dependency of the fecundity of Daphnia spec. on the food concentration was studied in Lake Constance. To eliminate the influence of temperature the number of eggs per adult female was plotted against the concentration of particulate carbon (<50 μm) at the estimated time of the production of the eggs. The curve obtained is similar to the results of laboratory investigations. The minimum food concentration for egg production is slightly above 0.2 mg C/1; at 0.7 mg C/1 the curve reaches a plateau. The absolute values of the threshold concentration and the “incipient limiting level” are compared to laboratory results. It appears that the shift of the field curve to higher concentrations is caused by the imcomplete availability of the 50 μm particulate carbon fraction to the daphnids. Daphnia in Lake Constance seem to be food limited during most of the year.

Dependence of particle production in high energy heavy ion collisions on the nuclear equation of state

Abstract: The total pion production cross section in central high energy heavy ion collisions depends strongly on the nuclear equation of state. This fact can be used to detect phase transitions from normal nuclear matter into abnormal superdense states (density isomers).

Spontaneous vacuum decay of supercritical nuclear composites

Abstract: We show that in deep inelastic heavy ion collisions withZ 1+Z 2> 173 the spontaneous decay of the neutral vacuum by emission of positrons may be isolated from other competing positron producing processes. From the details of the spontaneous positron spectrum information about the nature (lifetime, shape and angular momentum) of the composite nuclear system may be derived.

Satisfiability Is Quasilinear Complete in NQL

Abstract: Considered are the classes QL (quasilinear) and NQL (nondet quasllmear) of all those problems that can be solved by deterministic (nondetermlnlsttc, respectively) Turmg machines in time O(n(log n) ~) for some k Effloent algorithms have time bounds of th~s type, it is argued. Many of the "exhausUve search" type problems such as satlsflablhty and colorabdlty are complete in NQL with respect to reductions that take O(n(log n) k) steps This lmphes that QL = NQL iff satisfiabdlty is m QL

Effect of aminoglycosides on proximal tubular membranes of the human kidney.

Abstract: The effect of the aminoglycosides amikacin, gentamicin, netilmicin sisomicin and tobramycin on the proximal tubule of the human kidney was investigated in 78 healthy subjects Fifteen adults were each given gentamicin, sisomicin or tobramycin 3 mg/kg bodyweight, 10 subjects received netilmicin 3 mg/kg or amikacin 15 mg/kg additionally seven subjects amikacin 10 mg and six subjects netilmicin 6 mg on three consecutive days The principal enzyme of the brush border membrane of the proximal tubule, alanine aminopeptidase (AAP), was determined enzymatically and immunologically in 24-hour urines The effects of the various aminoglycosides on the membranes were different Less of membrane AAP was greatest after amikacin and was least after tobramycin There was no difference between gentamicin, netilmicin, and sisomicin, which had an effect intermediate between the other two compounds The elimination of AAP occurred at intervals which might possibly have been caused by impairment of cell cycles

Effect of sublingual nitroglycerin in emergency treatment of severe pulmonary edema.

Abstract: Twenty-two patients with clinical signs of pulmonary edema (orthopnea, cyanosis, profuse sweating and pulmonary rales∗) were studied and separated into two groups. In seven patients (Group A), hemodynamic studies were performed. Pulmonary arterial pressure and cardiac output were measured during the emergency condition of severe pulmonary edema. Within 10 minutes after sublingual administration of nitroglycerin, 1.6 mg, left ventricular filling pressure decreased from 33 ± 10 (mean ± 1 standard deviation) to 24 ± 8 mm Hg, and cardiac output increased significantly from 3.3 ± 0.8 to 3.7 ± 0.8 liters/min. In one patient with recent myocardial infarction, left ventricular filling pressure decreased from 50 to 27 mm Hg within 5 minutes. Orthopnea and pulmonary rales disappeared rapidly. In 15 patients (Group B), the clinical course was observed and documented. These patients received one to six doses of 0.8 to 2.4 mg of nitroglycerin sublingually at intervals of 5 to 10 minutes. Five minutes after administration, the first evidence of clinical improvement was observed in seven of these patients. After 15 to 20 minutes, pulmonary rales disappeared or decreased in 11 and dyspnea decreased in 14. The elevated arterial blood pressure and heart rate decreased significantly. Only one patient with terminal pulmonary edema remained refractory to therapy. Thus, sublingual nitroglycerin had beneficial effects in the emergency treatment of classic pulmonary edema. Elevated left ventricular filling pressure decreased and cardiac output increased within 5 minutes. These hemodynamic changes produced immediate clinical improvement.

Diurnal rhythm in the central dopamine turnover in the rat

Abstract: Under controlled conditions of environmental light and darkness of 12:12 h the turnover of dopamine and noradrenaline in brain of male Wistar rats was studied at different times of the day. The turnover was calculated from the decline of the amine concentrations either after inhibition of the tyrosine-hydroxylase with H 44/68 (200 mg/kg, i.p.) or after inhibition of the dopamine-β-hydroxylase with FLA 63 (40 mg/kg s.c.). Whereas the noradrenaline turnover showed only slight but not significant variations within 24 h, the turnover of the central dopamine exhibited significant variations with increased turnover rates in the second half of the light and first half of the dark period. Thus, diurnal variations have to be taken into account when studying the effects of drugs on the turnover of biogenic amines in the central nervous system.

Finite-perturbation calculation of static quadrupole and mixed dipole-octupole polarizabilities for the ground states of the first-row atoms

Abstract: Static quadrupole and mixed dipole-octupole polarizabilities are calculated from correlated wave functions for the ground states of the first-row atoms with estimated uncertainties of less than 3%. The following mean quadrupole polarizabilities are obtained for the atoms Li through Ne (in atomic units): 1428; 301.8; 145.7; 64.20; 30.72; 21.20; 12.69; 7.726. Correlation contributions are found to range from -12% (Be) to +20% (O).

Neutron emission in strongly damped collisions of /sup 86/Kr on /sup 166/Er at 602 MeV

Abstract: The neutron multiplicity was measured in coincidence with both binary products of the strongly damped collisions of $^{86}\mathrm{Kr}$ on $^{166}\mathrm{Kr}$ at 602-MeV beam energy. The measured ratio of the neutron multiplicities for the light and heavy fragments is in good agreement with the corresponding mass ratio for all mass divisions. The observed multiplicities as well as velocity and angular distributions of the neutrons are consistent with statistical-model calculations assuming isotropic evaporation of neutrons from fully accelerated, unpolarized fragments.

Systematic Investigations of Binding Energies of Inner-Shell Electrons in Superheavy Quasimolecules

Abstract: Electronic binding energies in superheavy quasimolecules are calculated using the monopole approximation, finite size and screening effects are included The validity of the monopole approximation is discussed A phenomenological description of the binding energy as a function of the total charge (Z1 + Z2) and the two-center separation R is given It is shown, that the 1sσ-ionization rate does not depend on the projectile or target charge, but only on the total charge of the superheavy quasimolecule

Development of the filiform hairs on the cerci of Gryllus bimaculatus deg. (saltatoria, gryllidae).

Abstract: The filiform hairs, mechanoreceptors of Gryllus, pass through six developmental stages during the last larval stage. The cytoplasm of their sense cells suggests intensive synthesis of protein for cellular metabolism and intercytoplasmic exchange of material via glial evaginations. Ultrahistochemical tests demonstrated acid phosphatase in the lysosomes as well as in components of the Golgi apparatus. There was no significant change in the appearance of the sense cell cytoplasm, indicating a maintained functional state also during molting. The new cuticular apparatus is formed after apolysis by the three enveloping cells. Formation of the replacement hairs is initiated by a cytoplasmic outgrowth of the trichogen cell. During morphogenesis of the new hair, the microtubules serve as a cytoskeleton and probably control the flow of vesicles, which contain phenol oxidase, also demonstrated in the Golgi apparatus, and are incorporated into the new cuticle. Bundles of microfibrils are involved in the surface sculpturing of the replacement hair. The trichogen cell also forms a number of structural elements, e.g. the “cup” and “strut” marked geometric peculiarities of which indicate that they are important in the spatial orientation of the dendrite and thus also in transduction. Reduction of the apical cell membrane of the tormogen cell after apolysis permits unrestricted growth of the new hair into the exuvial space. The tormogen cell participates in the formation of the joint membrane, parts of the socket and the articulation of the hair.

Scaling behaviour of inner-shell ionization in superheavy quasi-molecules

Abstract: We derive an approximate analytical formula for theK-shell ionization in collisions of very heavy atoms. The impact parameter and bombarding energy dependence are well described. The binding energy of the bound state at closest approach enters in a simple way, which could provide an experimental method for a spectroscopy of quasimolecular states.

The effect of pentoxifylline on the flow properties of human blood.

Abstract: SummaryRecent investigations have revealed that erythrocytes from patients with chronic arterial occlusive disease are significantly less deformable than red blood cells from healthy subjects. The influence of pentoxifylline on red blood cell fluidity was measured by a standard filtration technique using 8 μm membrane filters. Impaired deformability of erythrocytes was significantly improved in patients suffering from peripheral vascular disorders following intravenous injection of 200 mg pentoxifylline. Studies on reduced red cell deformability induced by hyperosmolarity in vitro showed that pentoxifylline (4 and 20 μg/ml) produced a dose-dependent improvement both in blood from healthy subjects and from patients with peripheral arterial occlusive disease. The results suggest that the positive therapeutic effect of pentoxifylline in peripheral arterial occlusive disease is mediated by improving red cell fluidity in the microcirculation.

Cytogenetic and histologic analyses of spontaneous abortions

Abstract: In a study of spontaneous abortions the correlations between karyotype (166 cases), anamnestic data, and macroscopic and histologic findings in placentas (107 cases) and embryos (73 cases) were analyzed. The main results were: 1. The rate of chromosomal aberrations was 39%. Trisomies predominated (60%), followed by monosomy X (20%), triploidies (14%), and structural aberrations (6%). 2. In trisomies a clear prevalence of female sex constitution (2:1) was observed. In normal karyotypes a slight prevalence of females was seen (1.2:1). 3. With increasing maternal age, more trisomies were found in the abortions. 4. Women whose index abortion had a normal karyotype had a history of fewer births but more abortions. 5. Trisomies of acrocentric chromosomes were mainly chorionic sacs with an embryo, while trisomies of the other autosomes resulted in intact empty sacs. 6. The average developmental stage of the embryos was 5 weeks, with a mean gestational age of 14 weeks. Gross malformations were found in 58% of the embryos.

Lyriform slit sense organ: Thresholds and stimulus amplitude ranges in a multi-unit mechanoreceptor

Abstract: Spike discharges were recorded separately from the individual slits of a lyriform organ to examine the physiological significance of the close parallel arrangement of sensory units in lyriform organs of arachnids. The organ studied lies on the posterior aspect of the spider leg tibia. It consists of 7 slits and is stimulated by induced lateral deflection of the metatarsus. According to previous model studies (Barth and Pickelmann, 1975) marked differences in the sensitivity of the individual slits were expected (Fig. 1). 1. Slit 1 is the longest and a peripheral slit in the group and outstanding for its low threshold, spontaneous activity, and phasic discharge characteristics. Allother slits examined (slits 2, 3, 4, 5, and 6) respond to a sustained ramp and hold stimulus with an initial peak and a subsequent regular (power law) decline in discharge frequency before they start bursting (Fig. 2). 2. Threshold stimulus amplitudes (ramp and hold stimuli, rise time 5 ms), given in degrees of metatarsal excursion, vary by a factor of nearly 90 among Slit 2 (0.01°), Slit 3 (0.11°), Slit 4 (0.42°), Slit 5 (0.65°), and Slit 6(≧0.92°) (Fig. 3). 3. The stimulus amplitude ranges of the slits overlap and differ only with respect to low amplitudes. Slit 2 covers a spectrum of stimulus amplitudes of at least 45 dB (× 177). This is also the value for the entire organ not considering Slits 1 and 7 (Fig. 4). 4. The stimulus response curves are saturation curves (ramp and hold stimuli; spike frequency of first 100ms). By arranging several slits to form a compound organ, the range of high increment sensitivity is enlarged as compared to the individual slit (Fig. 5).

Response characteristics of inferior colliculus neurons of the awake CF-FM batRhinolophus ferrumequinum

Abstract: In horseshoebats two-tone stimulation of inferior colliculus neurons with the first tone pulsed and fixed at the best excitatory frequency (BEF) and 10–30 dB above threshold, and a second continuous tone with variable frequency and intensity within the given range, led to a reduction of the response to the fixed tone in nearly all cases, i.e., inhibitory areas are widespread in inferior colliculus neurons. Furthermore, this two-tone stimulation disclosed, that best inhibitory frequencies (BIF) were often nearly the same as the BEF, with BIF-thresholds more frequently being below that one of BEF. In “filter”-neurons (i.e. neurons with BEF in the frequency range of the reference frequency (RF)) there was no inhibition discernable if the continuous tone was 500–4000 Hz below BEF and from individual RF to 3500 Hz below RF (Fig. 1). This gap of inhibition ranged from 78–83,5 kHz in all horseshoebats tested. The vicinity of this gap of inhibition to the BIF in the same neuron disclosed high frequency specifity of inhibitory influences. The frequency range, where this gap of inhibition occurred was moreover the same as that causing enhancement to second stimuli (Fig. 1 B), as well as that causing off-responses and showing non-monotonic spike count functions.

Spectroscopy of Electronic States in Superheavy Quasimolecules

Abstract: We show that information about quasimolecular electronic binding energies in transient atomic systems of $Z={Z}_{1}+{Z}_{2}$ up to 184 can be obtained from three sources: (1) the impact-parameter dependence of the ionization probability; (2) the ionization probability in head-on collisions as a function of total nuclear charge $Z$; (3) the delta-electron spectrum in coincidence with $K$-vacancy formation in asymmetric collisions. Experiments are proposed and discussed.

On Counting Equations

Abstract: Productive Sraffa joint production systems are known to possess a number of properties which appear to be counterintuitive, if contrasted with single product systems: prices may fluctuate even if expressed in terms of the wage rate, they may turn negative, the standard commodity may not exist, etc. If joint production is, by contrast, approached in terms of inequalities (von Neumann’s method), positive prices and a tradeoff between real wages and the rate of profit obtain but the solution will in general not allow the activation of all processes, some commodities are overproduced and the resulting system of commodities with positive prices in activated processes need not be ‘quadratic’, i.e. the number of positive activity levels need not be equal to the number of positive prices in an optimal solution.

Brachiopods: biomechanical interdependences governing their origin and phylogeny.

Abstract: The adaptive advantage of epibenthic articulate brachiopods over inarticulate forms resulted from a modification of the mechanics of shell opening from an indirect hydraulic system to a direct muscular one. As a consequence, the articulate brachiopods were able to reduce the complex muscular system of the ancestral inarticulates, freeing two-thirds of the space within the shell for enlargement of the feeding apparatus. The original hydraulic mechanism of the inarticulate brachiopods most likely evolved from the hydrostatic skeleton of metameric lower invertebrates, probably polychaete-like annelids, as shown by a biomechanical analysis. The transitional stages between such annelids and inarticulate brachiopods are presented and explained as adaptive improvements in body construction.

Multiple product techniques with properties of single product systems

Abstract: In the context of Sraffa systems most economists tend to avoid joint production and prefer to discuss single product systems because of their simple and elegant properties which have often been represented under the familiar headings of activity analysis or linear economic systems outside the circle of the Sraffa school It is true that joint production raises a number of intricate problems; no straightforward economic assumptions are known which could be made to ensure that prices in joint production systems are positive at a given rate of profit prior to truncation, the distinction between basics and non-basics is not easily maintained in the presence of joint production, etc Sraffa (1960) has hinted at many of the problems involved I believe, however, that it is possible to characterise those instances of joint production systems which retain some of the simple properties of single product systems, to distinguish them analytically from those with more paradoxical properties and to relate the paradoxes appearing in the theoretical model to obstacles to the competitive formation of prices in the real world

Chemical cross-linking of protein to RNA within intact ribosomal subunits from Escherichia coli.

Abstract: Bifunctional reagents, namely bis-(2-chloroethyl)-amine (“nitrogen mustard”) and activated esters of 3-(2-bromo-3-oxobutane-1-sulphonyl)-propionic acid (“bromo-ketone reagent”) are used to cross-link protein to RNA within intact ribosomal subunits. The cross-linked proteins are analysed on two different two-dimensional gel electrophoresis systems, and the existence of a stable cross-linkage is demonstrated by isolating cross-linked protein-oligonucleotide complexes from subunits containing 32P-labelled RNA. Proteins S3, S4, S5, S9/S11 and S13 from the 30S subunit, and proteins L1 and L2 from the 50S subunit were cross-linked to RNA by the nitrogen mustard, together with a number of other so far unresolved proteins. Correspondingly S3, S4, S7, S9/S11, and L2 were cross-linked by the bromoketone reagent, although in lower yield. The reagents should prove useful for topographical studies on ribosomal subunits, and arguments are presented favouring the use of non-cleavable and relatively non-specific RNA-protein cross-linking reagents for such studies.

Studies on the Control of Development

Abstract: Ribosomes from vegetative cells (vegetative ribosomes) of Bacillus subtilis synthesize guanosine 3′(2′)-diphosphate 5′-diphosphate (p2Gp2) and guanosine 3′(2′)-diphosphate 5′-triphosphate (p3Gp2). In contrast, ribosomes isolated from sporulating cells (sporulation ribosomes) synthesize adenosine 3′(2′)-diphosphate 5′-diphosphate (p2Ap2) and adenosine 3′(2′)-diphosphate 5′-triphosphate (p3Ap2). The products obtained with the aid of vegetative ribosomes were characterized by comparison with authentic substances in two chromatographic systems. The reaction mechanism is identical with that found in Escherichia coli, since [3H]GTP or GDP is pyrophosphorylated by ATP to form p2Gp2 and p3Gp2. Omission of ATP completely stops the formation of any reaction products. Furthermore, no reaction products are observed when GTP or GDP are omitted in a reaction mixture containing vegetative ribosomes. In contrast, incubation of sporulation ribosomes with ATP alone or ADP and ATP results in the formation of two products identified as p2Ap2 and p3Ap2 by their mechanism of synthesis as well as chemical and enzymatic degradation. Sporulation ribosomes (isolated at least an hour after the end of logarithmic growth) synthesize drastically less (by a factor of 100) p2Gp2 and p3Gp2. Vegetative ribosomes, on the other hand, synthesize only 1/100 the amount of p2Ap2 and p3Ap2 compared to sporulation ribosomes when isolated at least an hour before the end of logarithmic growth. By using washed ribosomes and ribosomal wash from vegetative and sporulation ribosomes, we were able to show that changes in the composition of ribosomes (probably in ribosomal proteins and/or ribosome-associated factors) must occur during the transition from vegetative to sporulating cells. Washed ribosomes from vegetative cells cannot replace washed ribosomes from sporulating cells to synthesize p2Ap2 and p3Ap2 in the presence of ribosomal wash from sporulating cells and vice versa. During the transition from one type of ribosomes to the other, as far as the unusual nucleotide-synthesizing activity is concerned, both types of nucleotides can be synthesized. While the ability to synthesize p2Gp2 and p3Gp2 decreases approximately at the end of logarithmic growth, the ability to synthesize p2Ap2 and p3Ap2 increases at the same time. The reason behind this obvious change in ribosomal structure and associated factors is discussed in the light of our finding that these changes are not observed in some early blocked asporogenous mutants. The observation that ribosomes from sporulating cells synthesize traces of p2Gp2 and p3Gp2 (by a factor of almost 100 less than vegetative ribosomes) is probably due to the presence of some non-sporulating cells in any B. subtilis culture. Likewise, there are always some spores contained in a vegetatively growing culture, which are probably responsible for the observed small amounts of p2Ap2 and p3Ap2 synthesized.

Results of Computer Tomography on Chronic Alcoholics

Abstract: Sixty adult patients with chronic alcoholism were examined by CT. Psychiatric and neurologic syndromes were given equal consideration. Pronounced brain atrophy was found in 75% of the cases. Cortical, as opposed to subcortical, atrophy was apparent in 64%; it was found especially in the frontotemporal region and cerebellum. Cases of Wernicke's encephalopathy as well as epileptic manifestations revealed global signs of atrophy, not restricted to the brain stem. Further correlations to problems of mental deficiency in alcoholism are discussed together with earlier results.