Showing papers by "University of Cologne published in 1974"
TL;DR: It is shown that the carboxy terminus of lac repressor is dispensable, and fusions between the i (lac repressor) and z (β-galactosidase) genes are found which produce fully active Lac repressor covalently linked to active β-galactsidase.
Abstract: GENETIC analysis of i gene mutants which had lost the capacity to bind operator but not inducer suggested that lac repressor binds with its amino terminus to lac operator1. Here we will show that the carboxy terminus of lac repressor is dispensable: We found fusions between the i (lac repressor) and z (β-galactosidase) genes (Fig. 1) which produce fully active lac repressor covalently linked to active β-galactosidase.
180 citations
TL;DR: This chapter concentrates on the biophysical aspects of sound communication, with a focus on the impedances of the sound transmitter, the medium, and the sound receptor.
Abstract: Publisher Summary The last decades has seen an increasing interest in the sound communication of insects. Much information has been accumulated in “classical” fields, such as the anatomy of sound-producing and sound-receiving structures, the analysis of sounds, acoustic behavior, and hexing. This chapter concentrates on the biophysical aspects of sound communication. Both the sound-producing mechanisms and the sound-receiving structures have evolved independently in a number of insects. The main problem of bioengineering in insect sound communication is that of matching the impedances of the sound transmitter, the medium, and the sound receptor. This problem is similar to the impedance matching of electrical equipment: For the transmission to be efficient, the output impedance of the sender should be low, compared with the input impedance of the receiver. In sound emission, the mechanical impedance of the transmitter (the vibrating parts of the insect) should be low, compared with that of the air (the radiation impedance). In sound reception, the impedance of the air should be low, compared with that of the sound-receiving structure. The frequency range of insect sounds is limited, mainly by the impedance problem because the radiation impedance depends very much upon the size of the object relative to the wavelength of sound.
171 citations
TL;DR: In this article, the ferromagnetic Ising model on a Cayley tree lattice exhibits a new phase transition at the field $B=0$ below the Bethe-Peierls transition temperature, where the leading nonanalytic part of the free energy is of the form ${B}^{\ensuremath{\kappa}}, where the "critical" exponent increases smoothly from one to infinity as the temperature goes from 0 to ${T}
Abstract: It is shown that the ferromagnetic Ising model on a Cayley tree lattice exhibits a new type of phase transition at the field $B=0$ below the Bethe-Peierls transition temperature ${T}_{\mathrm{BP}}$. The leading nonanalytic part of the free energy is of the form ${B}^{\ensuremath{\kappa}}$, where the "critical" exponent $\ensuremath{\kappa}(T)$ increases smoothly from one to infinity as the temperature goes from 0 to ${T}_{\mathrm{BP}}$. This implies a transition of "continuous" order $\ensuremath{\kappa}$.
155 citations
01 Mar 1974-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: In this paper, the neuromuscular activity underlying stridulation was recorded in freely moving animals using flexible wire electrodes (diameter 20-30 μm) which allowed the functional identification of individual motor units.
Abstract: 1.
Sound production of grasshoppers is based upon central motor patterns which are hierarchically organized at various functional levels (Fig. 2). These involve coordination (i) of single motor units belonging to the same muscles, (ii) of muscles relating to one hindleg, and (iii) of laterally homologous muscles moving the left and the right hindleg, respectively.
2.
The motor organization at the first two levels has been investigated comparatively in several species. The neuromuscular activity underlying stridulation was recorded in freely moving animals using flexible wire electrodes (diameter 20–30 μm) which allowed the functional identification of individual motor units (Fig. 3). Up to 30 electrodes were chronically implanted into the metathoracic muscles without restricting the behaviour.
3.
The motor patterns are based upon certain principles some of which are generally valid for all species: (i) The individual units are characterized by discrete types of activity (Fig. 4). (ii) Motor units and muscles are always recruited in a fixed order (Figs. 1, 3, 10).
4.
The co-ordination of single units does not follow a general scheme but it reflects features of the specific song patterns (Fig. 5). The muscles producing the movements of one hindleg are also specifically co-ordinated: (i) In rapidly stridulating species the sets of antagonistic muscles are coupled in an unequivocal (unimodal) manner from which the pattern of leg movements can easily be deduced (Figs. 11, 12, 13). (ii) On the other hand, in slowly stridulating species the antagonistic muscles are coupled in two ways, since several of them are recruited both before the beginning and at the end of the leg strokes (Figs. 7–9). Maximum of motor activity is usually found at the end of the upward movements where the activities of both the elevator and depressor muscles partly overlap (Fig. 7b).
142 citations
TL;DR: In this article, a LIDAR system equipped with a tunable dye laser was used for remote measurements of atmospheric NO2 concentrations by means of a Lidar system with the differential absorption method.
Abstract: Remote measurements of atmospheric NO2 concentrations by means of a LIDAR system equipped with a tunable dye laser are reported. Using the differential absorption method, concentration values of about 0.2 ppm were detected over the city of Cologne at distances up to 4 km.
93 citations
TL;DR: A combination of the main signs, reticular erythema and mucinosis, was used to name this entity REM syndrome, with some relation to sun exposure, but the full spectrum of xenon‐light did not cause any abnormal reactions.
Abstract: SUMMARY
Four patients, three females and one male, were observed in Cologne with sheet- or net-like erythema of the upper chest and of the back, with a tendency to spread to the abdomen. The patients had no symptoms with the exception of itching in one case and itching after sunburn in another. Histo-logically the epidermis was normal, apart from slight hydropic degeneration and some minor degree of spongiosis. The main features were: dilated blood vessels in the dermis, with a more or less pronounced perivascular infiltrate of round cells, and, in addition, deposits of a substance which stained with alcian blue. Oral treatment with Rhetis was of some benefit, otherwise therapy, including corticosteroids, was not successful. Other antimalarial drugs were not used. There was some relation to sun exposure, but the full spectrum of xenon-light did not cause any abnormal reactions. Since it was not possible to relate these findings to any known syndrome, a combination of the main signs, reticular erythema and mucinosis, was used to name this entity REM syndrome.
89 citations
TL;DR: In this paper, a polycrystalline magnesium, strontium, and barium surface cleaned by ion bombardment was investigated at room temperature in the oxygen dose range up to 12000 L by the static method of secondary ion mass spectrometry.
80 citations
TL;DR: All i(-d) and 98 i(s) mutations have been localized by deletion mapping and map in the region of the i gene, which codes for the aminoterminal part of the lac repressor.
Abstract: Selection methods for the isolation of i–d and is mutants are described. Two hundred and forty-seven i–d and 98 is mutations have been localized by deletion mapping. All i–d mutations map in the region of the i gene, which codes for the aminoterminal part of the lac repressor, whereas is mutations map in the middle of the i gene and at the proximal end of the i–d cluster.
69 citations
TL;DR: The results compared with the autopsy findings in these cases and data from studies on angular acceleration to the head of squirrel monkeys carried out by Unterharnscheidt and Higgins indicate the bridging vein disruption due to rotational movement of the head is obtained when the angular acceleration exceeds 4500 rad/sec2 and/or the change in angular velocity exceeds 50 rad/ sec.
Abstract: High-speed films recorded from head on collision tests with cadavers have been analysed with respect to the angular acceleration and angular velocity which were evaluated with Smoothed Cubic-Spline Functions. These results compared with the autopsy findings in these cases and data from studies on angular acceleration to the head of squirrel monkeys carried out by Unterharnscheidt and Higgins indicate the bridging vein disruption due to rotational movement of the head is obtained when the angular acceleration exceeds 4500 rad/sec2 and/or the change in angular velocity exceeds 50 rad/sec. These tolerance levels are compared with data from collision experiments on living human beings.
69 citations
TL;DR: The evidence presented here demonstrates that the 50 to 90S viral DNA represents adenovirus DNA covalently integrated into cell DNA.
Abstract: KB cells productively infected with human adenovirus type 2 contain an alkalistable class of viral DNA sedimenting in a broad zone between 50 and 90S as compared to 34S for virion DNA. This type of DNA is characterized as viral by DNA-DNA hybridization. It is extremely sensitive to shear fragmentation. Extensive control experiments demonstrate that the fast-sedimenting viral DNA is not due to artifactual drag of viral DNA mechanically trapped in cellular DNA or to association of viral DNA with protein or RNA. Furthermore, the fast-sedimenting DNA is found after infection with multiplicities between 1 and 1,000 PFU/cell and from 6 to 8 h postinfection until very late in infection (24 h). Analysis in dye-buoyant density gradients eliminates the possibility that the fast-sedimenting viral DNA represents supercoiled circular molecules. Upon equilibrium centrifugation in alkaline CsCl density gradients, the fast-sedimenting viral DNA bands in a density stratum intermediate between that of cellular and viral DNA. In contrast, the 34S virion DNA isolated and treated in the same manner as the fast-sedimenting DNA cobands with viral marker DNA. After ultrasonic treatment of the fast-sedimenting viral DNA, it shifts to the density positions of viral DNA and to a lesser extent to that of cellular DNA. The evidence presented here demonstrates that the 50 to 90S viral DNA represents adenovirus DNA covalently integrated into cell DNA.
67 citations
TL;DR: In this article, a level crossing experiment on the hyperfine structure of Na23 was performed using a nitrogen laser pumped dye laser for the excitation of the Na atoms, and the fluorescent light was observed in time intervals which were initiated up to seven lifetimes after excitation.
Abstract: A level crossing experiment on the hyperfine structure of the 32
P
3/2 level of Na23 was performed using a nitrogen laser pumped dye laser for the excitation of the Na atoms. The fluorescent light was observed in time intervals which were initiated up to seven lifetimes after excitation. Therefore the signal was only determined by atoms having survived in the excited state up to the initiating time. The minimum linewidth observed was 6 times smaller than the natural width. Neighbouring crossing signals, which overlap in a level crossing experiment using time integral observation of the fluorescent light, could be resolved. The accuracy of the hyperfine constants of the 32
P
3/2 level could be improved.
TL;DR: In this article, mean lifetimes of states in 41Ca and 41K were determined using the recoil distance Doppler shift method, using the mean lifetime of 41 Ca at 3370 keV (28 ± 5 ps ), 3830 keV(4.4 ± 0.3 ns ) and 3915 keV (−1.1 −0.3.
TL;DR: Using the differential absorption method, the NO2 concentration within the plume of a smoke stack and over the area of a chemical factory was measured as discussed by the authors, and the concentration of NO2 within the smoke stack was measured.
Abstract: Using the differential absorption method the NO2 concentration within the plume of a smoke stack and over the area of a chemical factory was measured.
TL;DR: In this paper, the ground state of a Fermi fluid is approximated by a Jastrow-ansatz, and the factorized Iwamoto-Yamada expansion of the radial distribution function is suitably rearranged.
TL;DR: It is demonstrated that the mutant lacks functional cyclic AMP receptor protein (CR protein) and it is concluded that, like many other inducible enzyme systems, expression of the enzymes of the fad system requires cyclicAMP and the CR protein.
Abstract: The strong repression of inducible synthesis of the enzymes of fatty acid degradation by glucose can be partially relieved by the addition of cyclic adenosine 3′,5′ monophosphate (cyclic AMP) to the growth medium. This reversal of the glucose effect by cyclic AMP is not observed in a mutant (K29) that is unable to grow on fatty acids as sole carbon source and that was found to synthesize low levels of several enzymes specified by the fad regulon. In a revertant selected for the ability to grow on oleate these effects are concomitantly relieved. By both genetic (co-transduction of the mutation with the strA locus) and biochemical experiments (an extract of the mutant strain does not show the cyclic AMP-dependent stimulation of the deoxyribonucleic acid-directed in vitro synthesis of the enzymes of the gal operon), it is demonstrated that the mutant lacks functional cyclic AMP receptor protein (CR protein). It is concluded that, like many other inducible enzyme systems, expression of the enzymes of the fad system requires cyclic AMP and the CR protein.
TL;DR: Results support evidence that a double—metabolic and neurogenic—mechanism is involved in the control of cerebral blood flow, and it is suggested that the effects during vagosympathetic stimulation are completely neurogenic, the effects During trigeminal stimulation mainly metabolic, and the effectsDuring medullary stimulation both metabolic and Neurogenic in origin.
01 Sep 1974-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: The study of the motoneuron populations that drive the participating muscles shows that the muscular economy has a neural analogue: bifunctional motoneurons which participate in both forms of sound production are remarkably output-specific.
Abstract: Insects have a particularly economical neuromuscular system: Many thoracic muscles move both the legs and the wings, being co-ordinated in a reversable synergistic-antagonistic relationship. Consequently, the same set of motoneurons may be involved in behavioural activities performed by different appendages, e.g. leg and wing stridulation in several acridid grasshoppers. The motor patterns underlying these different behaviours have been investigated in the alpine grasshopperStenobothrus rubicundus (Germ.). The study of the motoneuron populations that drive the participating muscles shows that the muscular economy has a neural analogue: Bifunctional motoneurons which participate in both forms of sound production are remarkably output-specific. They produce the same firing pattern, no matter which behaviour they are involved in. Consequently, fundamental pattern parameters of wing beat appear in leg stridulation when these motoneurons become active.
TL;DR: The sexual behaviour of Chorthippus curtipennis females consists of ‘primary defence’, passive and active copulatory readiness, ‘secondary defence‘, and egg-laying behaviour.
TL;DR: A comparison of the polypeptide composition of the incomplete particles with that of the complete virions by electrophoresis on polyacrylamide slab gels demonstrates that both types of particles contain hexons, penton base and fibers in similar relative amounts.
TL;DR: In this paper, the transient decay of large excess-carrier densities was investigated in a semiconductor and it was shown that the carrier decay is determined by the Auger recombination process.
Abstract: The transient decay of large excess-carrier densities was investigated in ${\mathrm{Hg}}_{1\ensuremath{-}x}{\mathrm{Cd}}_{x}\mathrm{Te} (x=0.205)$ at 77 K. Excess carriers were generated by bulk impact ionization in strong electric fields. A strong variation of the carrier lifetime with excess-carrier density was observed in the transient excess-carrier decay. The comparison with calculated values shows that the carrier decay is determined by the Auger recombination process. To our knowledge this is the first observed Auger-dominated transient carrier decay in a semiconductor. A typical Auger-dominated lifetime for carriers at excess-carrier densities not far from thermal equilibrium is 460 nsec for ${n}_{0}=9\ifmmode\times\else\texttimes\fi{}{10}^{14}$ ${\mathrm{cm}}^{\ensuremath{-}3}$ and ${\ensuremath{\mu}}_{H}=2.26\ifmmode\times\else\texttimes\fi{}{10}^{5}$ ${\mathrm{cm}}^{2}$/V sec at 77 K. This lifetime decreased to 90 nsec at an excess-carrier density equal to ${n}_{0}$. Photoconductivity experiments indicate that the majority-carrier lifetime can be enlarged due to minority-carrier trapping near contacts. This was established in photoresponse measurements with ${\mathrm{CO}}_{2}$ laser pulses. In addition to this, the Hall mobility was measured and analyzed between 4.2 and 200 K. Calculations for combined ionized-impurity and polar-optical-phonon scattering indicate that above 77 K the polar-optical-phonon scattering limits the mobility. This electron-phonon interaction was calculated taking into account the two-mode behavior of ${\mathrm{Hg}}_{1\ensuremath{-}x}{\mathrm{Cd}}_{x}\mathrm{Te}$. The high-field measurements have shown that in electric fields above 150 V/cm impact ionization occurs. Values of the carrier generation rate of ${\mathrm{Hg}}_{0.8}$${\mathrm{Cd}}_{0.2}$ Te were deduced from the time dependent $j(E)$ characteristics.
TL;DR: In this article, the Raman spectra of oriented cyrstals have been used to confirm the assignment of Raman active internal modes of K2SO4 and structurally related crystals.
Abstract: In order to confirm the assignment of the Raman active internal modes of K2SO4 and structurally related crystals, the Raman spectra of oriented cyrstals have been recorded. Using the relative integrated intensities of the bands as data, the transferability of the Raman tensors of the free SO ion to the crystals was investigated with, in general, good agreement between the calculated and measured intensity distribution. A linear dependence between the frequencies of the internal modes of the K2SO4, Rb2SO4 and Cs2SO4 crystals and the electronegativity of the cations could be observed. Also, a brief discussion about the nature of the lattice modes of these crystals is included.
TL;DR: In this paper, a level crossing experiment on the 6s 6p 1 P 1 level of Ba I was performed using a narrow-band tunable dye laser and a strongly collimated atomic beam.
TL;DR: In this article, an investigation on the low energy cosmic ray products 26 Al and 53 Mn in 18 chondrites encompassed several side aspects in meteoritics The ratio of observed to calculated specific activity of 26 Al remains constant within ±15 per cent of a mean of 093, consistent with Fuse and Anders' observation of invariance of the 26 Al-production rate with depth and size.
TL;DR: Assay conditions, intracellular distribution and change of activity during greening of etiolated seedlings of Vicia faba L. have been investigated for aldose reductase, UDP-glucose pyrophosphorylase, and phosphatidate phosphatase, which were found to be soluble proteins of the cytoplasm.
Abstract: Assay conditions, intracellular distribution and change of activity during greening of etiolated seedlings of Vicia faba L. have been investigated for aldose reductase (EC 1.1.1.21), UDP-glucose pyrophosphorylase (EC 2.7.7.9), UDP-glucose 4-epimerase (EC 5.1.3.2) and phosphatidate phosphatase (EC 3.1.3.4). The first three enzymes were found to be soluble proteins of the cytoplasm, whereas phosphatidate phosphatase was found in the soluble and a sedimentable (15000 Xg) fraction.
TL;DR: In this article, the plating efficiency of single cells isolated from green callus cultures of Nicotiana tabacum var. "Samsun" and plated in densities of less than 100 cells ml(-1) was improved by more than 100%.
Abstract: Light increases the plating efficiency of single cells isolated from green callus cultures of Nicotiana tabacum var. "Samsun" and plated in densities of less than 100 cells ml(-1) by more than 100%. At optimal light intensities plating efficiences between 80 and 90% were achieved with green cells, whereas the growth of isolated cells from chlorophyll free callus cultures was inhibited by light.Plated at low densities the isolated tobacco cells require the addition of kinetin and glutamine to a modified Murashige-Skoog-Medium for growth. The addition of these two substances is not necessary in the case of callus cultures or at higher plating densities (i.e. 500 or more cells ml(-1)). The requirement of kinetin for the growth of isolated cells can be met by the addition of small amounts of conditioned media from suspension cultures to the modified M+S-medium supplemented with glutamine, which demonstrates the production and release of a highly active cytokinine by the cells.
TL;DR: In this article, it was shown that charge migration after ionisation below the ionisation potential of primary amines towards the N atom does not occur via the σ-bonds, but by special interactions of the functional groups.
Abstract: An Hand von Alkylaminen, die ω-standig eine zweite funktionelle Gruppe (O, S, Se) tragen, wird gezeigt, das bei Ionisierung unterhalb des Ionisierungspotentials primarer Amine Ladungswanderung zum N, die schlieslich zur Bildung von CH2NH2+ fuhrt, nicht generell uber die σ-Bindungen, sondern uber spezielle Mechanismen erfolgen kann. Zusatzlich wird das Fragmentierungsverhalten einfacher Methyl-alkyl-selenide beschrieben.
By using alkyl amines ω-substituted with a second functional group (O, S, Se) it is shown that charge migration after ionisation below the ionisation potential of primary amines towards the N atom (which finally results in the formation of [CH2NH2]+) does not occur via the σ-bonds, but by special interactions of the functional groups. In addition, the fragmentation behaviour of simple methyl alkyl selenides is described.
TL;DR: In this paper, the states of free electrons in a magnetic field confined to a box of finite volume are determined and used to calculate the average magnetic moment and the non-dissipative electric and heat current in an unambiguous way.
Abstract: The states of free electrons in a magnetic field confined to a box of finite volume are determined and used to calculate the average magnetic moment and the non-dissipative electric and heat current in an unambiguous way. It is shown that for infinite volume the average magnetic moment coincides with the magnetization calculated by Landau. Similarly, for infinite volume, the non-dissipative transport coefficients coincide with those calculated by Zyryanov and Silin who use Landau's method and subtract the purely diamagnetic parts from the total currents. We think that our considerations give an answer to the often discussed question, why the Landau calculation of the magnetization and similar calculations of the non-dissipative transport coefficients are correct for a large system.
TL;DR: In this article, the specific heat of LaAl 2 and (La 1- x Ce x )Al 2 ( x ⩽ 00064) has been measured between 03 and 5 K, both in the superconducting and in the normal state.
TL;DR: In this article, the authors used the horseradish peroxidase (HRP) tracer to measure the permeability of the stria vascularis, spiral prominence and spiral ligament.
Abstract: The permeability of blood vessels in the stria vascularis, spiral prominence and spiral ligament has been investigated using the horseradish peroxidase (HRP) tracer technique. The distribution of the marker enzyme was studied 1/2-60 min after intravenous injection. The tissue was fixed in situ by vascular perfusion.