Showing papers by "Academy of Sciences of the Czech Republic published in 1973"
TL;DR: No evidence could be found for the existence of a tetraploid DNA complement in mouse Purkinje neurons despite indications to the contrary from a parallel cytophotometric study.
Abstract: — The DNA content of mouse Purkinje neurons was investigated employing a biochemical approach. Material for the biochemical assay was provided by means of a sedimentation velocity separation technique which yields bulk quantities of well-preserved Purkinje perikarya in a high degree of purity. The same amount of DNA/cell was recorded for mixed cerebellar cell somata (7·6 ± 0±2 pg/cell), as for the Purkinje perikarya enriched fractions (7±2 & 0·2 pg/cell). No evidence could be found for the existence of a tetraploid DNA complement in mouse Purkinje neurons despite indications to the contrary from a parallel cytophotometric study.
61 citations
TL;DR: This data indicates that the predominant role of the K-end of H-2 in mixed lymphocyte reaction in allograft rejection is related to that of the MLR-stimulating gene, while the determinants for cell-mediated lympholysis are unclear.
Abstract: 1. The role of the H-2 gene complex in allograft rejection 2. Genetic determinants of lymphocyte activation in the H-2 complex a. The predominant role of the K-end of H-2 in mixed lymphocyte reaction b. Superiority of K-end incompatibility in other test systems c. Identification of the MLR-stimulating (MLRS) determinants d. The H-2 linked MLR-capacitating (MLRC) gene 3. Genetic determinants for cell-mediated lympholysis (CML) 4. Summary
59 citations
TL;DR: Isothermal and non-isothermal kinetics are classified according to the viewpoint of rational approach in this article, where the appropriate selection of basic quantities and constitutive equations is stressed. And the meaning of partial derivatives is demonstrated in details.
Abstract: Isothermal and non-isothermal kinetics are classified according to the viewpoint of rational approach. The appropriate selection of basic quantities and constitutive equations is stressed. The extensive discussion recently focused to the meaning of the partial derivatives is reinvestigated and clarified considering the origin of following equation
$$\alpha = f(T,t)$$
whereα is the extent of reaction,T andt are the temperature and time respectively, andf represents a function. The meaning of partial derivatives is demonstrated in details. The disagreement sometimes claimed between the data evaluated by means of isothermal and non-isothermal kinetics is also reviewed, but no fundamental differences are established.
49 citations
TL;DR: In this article, the ionization potentials and electron affinities are calculated by the use of the many-body Rayleigh-Schrodinger perturbation theory up to the third order.
49 citations
TL;DR: A method for the evaluation of kinetic data of heterogeneous processes, including the most probable mechanism, from TG traces is described in this article, where results are illustrated for the decarbonization of calcite and magnesite in vacuo, and the dehydration of α-calcium sulphate hemihydrate.
Abstract: A method for the evaluation of kinetic data of heterogeneous processes, including the most probable mechanism, from TG traces is described. Results are illustrated for the decarbonization of calcite and magnesite in vacuo, and the dehydration ofα-calcium sulphate hemihydrate. The advantages of the approach to the study of the kinetics, resulting in descriptions based on the known process mechanisms are demonstrated.
31 citations
TL;DR: In this paper, a corrected version of the phase diagram based on the results obtained as well as on the critically selected data published previously by other authors had been suggested and discussed on the basis of a simple model.
25 citations
TL;DR: In this article, the demagnetization tensor of a cylinder is expressed by tabulated functions, which can be used to determine the demagnetic field of the cylinder along an arbitrary direction.
Abstract: All independent components of the demagnetization tensor of a cylinder are expressed by means of tabulated functions. That allows to determine the demagnetizing field of a cylinder homogeneously magnetized along an arbitrary direction. As an example the demagnetizing field is computed over the endface of a cylinder homogeneously magnetized perpendicular to its axis of rotation.
24 citations
TL;DR: The present study demonstrates that by using trypsin digestion, F(c)5μ fragment is relatively much more stable than Fabμ fragment.
Abstract: It has been shown previously that preparation of F(c)5μ and Fabμ fragments from IgM is limited both by low yields and incomplete cleavage and that digestion with hot trypsin is superior to papain in the absence of cysteine. The present study demonstrates that by using trypsin digestion, F(c)5μ fragment is relatively much more stable than Fabμ fragment. Optimum conditions for splitting with trypsin were 60°C for 20 min.
Sedimentation constants of F(c)5μ and Fabμ fragments were 10.9 and 3.7 S, respectively. Molecular weights derived from polyacrylamide disc electrophoresis in sodium dodecyl sulfate were 340 000 and 48 000 for F(c)5μ and Fabμ respectively. The molecular weight of F(c)5μ fragment falls to 33 600 after partial oxidative sulfitolysis.
Amino acid and sugar composition of the fragments were determined and accounted for approximately 85 % of the IgM molecule. That portion which was lost is most likely a glycopeptide cleaved from the hinge area.
22 citations
TL;DR: The presence of fine filamentous shell around the small compact nucleoli with segregation of nucleolar components suggested the possibility of the existence of transitional forms between such nucleoli and large nuclear bodies containing dense granules and fibrillar structures similar to theucleolar components.
17 citations
TL;DR: In this article, polybutadiene was solubilized in dilute solutions of styrene/Butadiene/Styrene block copolymers in selective solvents for polystyrene.
Abstract: Polybutadiene was solubilized in dilute solutions of styrene/butadiene/styrene block copolymers in selective solvents for polystyrene. The formed mixed micelles gave rise to a permanent turbidity of the solution. The systems were investigated by viscometry and light scattering. Using simplifying assumptions about the shape of the micelles, the micellar weights (up to 1010) and sizes (particle diameter up to 300 nm), as well as the average volume fractions of the polymer in the space occupied by a micelle (≈ 0,8–1,0) were estimated.
Polybutadien wurde in verdunnten Losungen von Styrol/Butadien/Styrol-Blockcopolymerisaten in selektiven Losungsmitteln fur Polystyrol solubilisiert. Die gebildeten Mischmicellen verursachten eine permanente Trubung der Losung. Die Systeme wurden viskosimetrisch und mit Hilfe der Lichtstreuung untersucht. Unter vereinfachenden Annahmen uber die Gestalt der Micellen wurden die Micellargewichte (bis 1010) und Grosen (Teilchendurchmesser bis 300 nm) der Micellen sowie die Mittelwerte des Volumenbruchs des Polymers in dem von einer Micelle besetzten Raum (≈ 0,8–1,0) abgeschatzt.
16 citations
TL;DR: In this paper, the use of macroporous copolymers of 2-hydroxyethyl methacrylate and ethylene dimethacrylated as sorbents of gas chromatography was investigated.
TL;DR: The experiments were performed using Nuclear Chicago Mark I and Nuclear Chicago Isocap/300 (counting at room temperature) liquid scintillation spectrometers and the counting efficiency was assessed using the method of channels ratio with external standards and with quenching calibration curves for I4C.
Abstract: IN RADIOASSAYS of choline acetyltransferase activity (EC 2.3.1.6) labelled acetylcholine (ACh) is formed during incubation from labelled acetyl-CoA. At the end of the incubation period, ACh has to be isolated from the incubation mixture and the amount of radioactive label present in ACh is measured. The extraction of ACh from aqueous solutions by sodium tetraphenylboron (Na-TPB) dissolved in ethyl butyl ketone, as proposed by FONNUM (1969a), is being widely used for this purpose (FONNUM, 19696, 1970; ISRAEL, 1970; ISRAEL, GAUTRON and LESBATS, 1970; BLACK, HENDRY and TVERSEN, 1971; TUEEK and GUTMANN, 1972). Extraction of ACh by Na-TPB dissolved in organic solvents is also used in other experiments when the radioactivity present in ACh is to be measured (RICHTER and MARCHBANKS, 1971). When a small amount of a solution of Na-TPB in ethyl butyl ketone is added to commonly used scintillation liquids (toluene with 2,5-diphenyloxazolc (PPO) 0.4 % (w/v) and 1,4-bis-(5-phenyloxazol-2-yl) benzene (POPOP) 0.01 % (wiv), BRAY’S (1960) scintillation liquid, etc.), Na-TPB forms a dense white precipitate. To overcome this difficulty FONNL‘M (1969~) introduced the use of toluene scintillation liquid with acetonitrile in which Na-TPB remains in solution. The use of toluene-acetonitrile scintillation medium is connected with several inconveniences: ( I ) acetonitrile is highly toxic; (2) occasionally a very slight precipitate may form when samples are left standing for a longer time; (3) acetonitrile decreases the counting efficiency when present in a toluene scintillation liquid simultaneously with ethyl butyl ketone. These inconveniences may be avoidcd by the use of a scintillation liquid containing toluene, PPO, POPOP and Triton X-100. and the counting efficiency may be further increased by including naphthalene in the scintillation medium. The experiments were performed using Nuclear Chicago Mark I (counting a t -2°C) and Nuclear Chicago Isocap/300 (counting at room temperature) liquid scintillation spectrometers. The counting efficiency was assessed using the method of channels ratio (pulse height shift) with external standards (’33Ba in the Mark I and 226Ra in the lsocap/300 apparatus) and with quenching calibration curves for I4C. Higher channels ratios indicate lower quenching (higher counting efficiency). When 0.5 ml of a solution of Na-TPB in ethyl butyl ketone (15 mg/ml) were added to 10 ml of toluene with PPO (0.4%, w/v) and dimethyl-POPOP (0.02%, w/v), a white precipitate was formed. It was found possible to dissolve the precipitate by adding 0.4 ml of Triton X-100; the solution was then stable for many days. The influence of ethyl butyl ketone, Na-TPB, acetonitrile, and Triton X-100 on the channels ratios and counting efficiencies may beseenfrom the results of a representative experiment summarized in Table I . The amounts of acetonitrile used in the experiment in Table 1 are the lowest amounts suficient for maintaining Na-TPB in solution. Comparison of vials No. 4 and 5 in Table 1 indicates that the scintillation solution with Triton X-100 quenches less than that with acetonitrile. Comparison of vials No. 2, 4 and 5 with vials 7, 9 and 10, respectively, indicates that the addition of naphthalene improves the counting efficiency for I4C in the scintillation solutions containing ethyl butyl ketone, both with acetonitrile and with Triton X-100. The presence of naphthalene had little effect on the counting efficiency in the vials which did not contain ethyl butyl ketone (compare vials No. 1 and 3 with vials No. 6 and 8, respectively). It has been found in other experiments that the channels ratios in toluene-PPO scintillation liquids with Na-TPB, ethyl butyl ketone, Triton X-100 and naphthalene (same composition as in vial No. 10 in Table I ) were unaffected when the concentration of dimethyl-POPOP was lowered from 0.02 to 0.01 % or when POPOP 0.01 or 0.02% was used instead of dimethyl-POPOP. Naphthalene in a final concentration of 4% (w/v) exerted an antiquenching effect of a similar magnitude as that produced in the experiment in Table 1 at 8 % concentration.
TL;DR: All but one of the specific pathogens of Tribolium castaneum were found in samples of insects from British food stores, and diseases may be of some economic importance by reducing or eliminating sources of infestation in undisturbed residues of food.
TL;DR: In this paper, the A3 absorption data measured at the Panska Ves Observatory on 2775 kHz were compared with the satellite X-ray and Lyman-α data.
TL;DR: In this article, the local demagnetizing fields on the surface of flat cylindrical samples (disc) are measured by means of the free radical electron paramagnetic resonance for several thickness-to-diameter ratios from 0·01 to 0·15 and at two values of the external magnetic field (around 4 and 14 kOe).
Abstract: The local demagnetizing fields on the surface of flat cylindrical samples (disc) are measured by means of the free radical electron paramagnetic resonance for several thickness-to-diameter ratios from 0·01 to 0·15 and at two values of the external magnetic field (around 4 and 14 kOe). An empirical expression for the demagnetizing field intensity is found and anisotropy of the demagnetizing field is detected in the sample plane. The experimental results are compared with the conclusions of the theory of Joseph and Schlomann.
TL;DR: In this article, it has been found that the magnitude of CRSS, the choice of the slip planes and the shape of the stress-strain curves depend on the angle between the compression axis and the Burgers vector (angleξ).
Abstract: Specimens of Fe-3·2 wt% Si alloy single crystals of various orientations, both with 18 ppm C and decarburized, have been deformed in compression (\(\dot \varepsilon \) ∼ 10−4 s−1) at different temperatures between 125 K and 293 K. It has been found that the magnitude of CRSS, the choice of the slip planes and the shape of the stress-strain curves depend on the angle between the compression axis and the Burgers vector (angleξ). The stress normal to the maximum resolved shear stress plane is strongly altered on changing the angleξ. The discussion of the obtained experimental results seems to indicate that the normal stress influences the structure of screw dislocation core and subsequently the dislocation mobility.
TL;DR: The concentration and temperature dependence of emission and excitation spectra was measured on powder A1N∶Eu phosphors in this paper, and it was shown that at low activator concentration the wide emission band is found in the blue green region, while at high concentration it is in green region.
Abstract: The concentration and temperature dependence of emission and excitation spectra was measured on powder A1N∶Eu phosphors. It was shown that A1N: Eu has two luminescent modifications which depend on the activator concentration. At low activator concentration the wide emission band is found in the blue-green region, while at high concentration it is in green region. The excitation spectra of A1N∶Eu consist of wide bands extended from 40×103 cm−1 to 22 × × 103 cm−1. The emission and excitation spectra are interpreted as transitions between energy levels of Eu2+ ions (4f7⇄4f6 5d transitions). The structure of the Eu2+ luminescent centres and the temperature dependence of luminescence are discussed.
TL;DR: In this article, the authors have studied lattice defects in TGS single crystals using both transmission and reflection X-ray topography and the Burgers vectors of most of them have been found.
Abstract: Lattice defects in TGS single crystals have been studied using both transmission and reflection X-ray topography. Dislocations of different types have been observed and the Burgers vectors of most of them have been found. Volume defects, their shape and distribution have been investigated and suggestions for the explanation of their character are given. Interactions between these defects and between them and ferroelectric domain walls are discussed.
TL;DR: In this article, a group-theoretical analysis of reflectivity measurements of Hg2Cl2 and Hg 2Br2 single crystals has been performed in polarized light and the results are compared with the existing data from other measurements and the large anisotropy of polar modes is briefly discussed.
Abstract: Far infrared (30–430 cm−1) reflectivity measurements of Hg2Cl2 and Hg2Br2 single crystals have been performed in polarized light. The spectra, which are in agreement with group-theoretical predictions, were analyzed by the oscillator fitting procedure and Kramers-Kronig method. The results are compared with the existing data from other measurements and the large anisotropy of polar modes is briefly discussed. The polarization vectors of all long-wavelength symmetry modes were determined group-theoretically.
TL;DR: The variations up to the fourth order of the total energy in the Peierls-Nabarro dislocation model are studied in this paper, where it is shown that the total total energy reaches the local functional minimum for the function f(x) (with positive df/dx) which is the solution of the PEI-differential equation.
Abstract: The variations up to the fourth order of the total energy in the Peierls-Nabarro dislocation model are studied. It is shown that the total energy reaches the local functional minimum for the functionf(x) (with positive df/dx) which is the solution of the Peierls-Nabarro integro-differential equation.
TL;DR: In this article, the authors measured the reflectivity of eight SbS1−xSexI mixed single crystals in 50-400 cm−1 region in polarized light at 25 and −170 ‡C. The existence of local and gap modes in this case was discussed.
Abstract: Far infrared reflectivity of eight SbS1−xSexI mixed single crystals was measured in 50–400 cm−1 region in polarized light at 25 and −170 ‡C. While the low-frequency ferroelectric mode shows clear one-mode behaviour the second B1u mode in 126–180 cm−1 region shows two-mode behaviour. The existence of local and gap modes in this case is discussed.
TL;DR: In this article, the authors investigated the linear viscoelastic and stress-strain behavior of poly(n-butyl methacrylate) networks at a content of crosslinking agent (ethyleneglycol dimethyl carbonylate) of c0-1 × 10−4 mole/cm3 in the rubber-like region in the temperature interval from 20 to 150°C.
Abstract: The linear viscoelastic and stress-strain behavior of poly(n-butyl methacrylate) networks at a content of crosslinking agent (ethyleneglycol dimethacrylate) of c0–1 × 10−4 mole/cm3 was investigated in the main transition and rubberlike region in the temperature interval from 20 to 150°C. The dependence of the unperturbed chain dimensions on temperature was determined from thermoelastic measurements in the rubberlike region; this dependence was unaffected by the content of crosslinking agent. Application of time–temperature superposition to the linear viscoelastic behavior did not give a continuous superimposed curve in the proximity of the rubberlike region; superposition within the whole time region required introducing the change of the unperturbed chain dimensions with temperature. This correction was sufficient for a sample with a higher content of the crosslinking agent. However, for loose networks (c< 0.1 × 10−4 mole/cm3) it was insufficient, because of another relaxation mechanism in the region of high temperatures. It was found that the intensity and temperature dependence of this relaxation mechanism, which is probably due to a change of the number of entanglements with temperature, are connected with the magnitude and the temperature dependence of the C2 constant of the Mooney-Rivlin equation.
TL;DR: In this article, the NMR field shifts for aqueous protons in solution containing paramagnetic inorganic compounds of Cu2+, Cr3+, Fe3+ and Mn2+ ions were measured using both internal and external NMR standards.
Abstract: There are presented measurements of the NMR field shifts for aqueous protons in aqueous solutions containing paramagnetic inorganic compounds of Cu2+, Cr3+, Fe3+ and Mn2+ ions. The measurements have been performed on samples in the form of transversally magnetized long cylinders using both the internal and external NMR standards. The experimentally determined shifts are related to the NMR field position of protons in pure water. The results for demagnetizing shifts are compared with the data which were computed from the magnetic susceptibility values (measured by magnetostatic method), the chemical shifts are compared with the results of other authors. Results of measurements indicate a small chemical shift of internal standards in some solutions.
TL;DR: In this paper, the lattice deformation across the antiphase boundary and the energy of both types (a/2 ǫ-111 anda/ǫ (100) ) of antiphases lying in the {110} plane are calculated using a series of three interatomic potentials fitted to experimental data.
Abstract: The lattice deformation across the antiphase boundary and the energy of both types (a/2〈111〉 anda〈(100〉) of antiphase boundaries lying in {110} plane are calculated using a series of three interatomic potentials fitted to experimental data. It is shown that the relaxation of atomic planes in the vicinity of antiphase boundary is important for thea/2〈111〉 antiphase boundary and is negligible for a 〈100〉 antiphase boundary in the DO3 structure.
TL;DR: In this article, free particle states and S-matrix are defined on carrier spaces of representations of the Weyl groupW (Poincare group extended by dilatations).
Abstract: Free particle states andS-matrix are defined on carrier spaces of representations of the Weyl groupW (Poincare group extended by dilatations). By using Clebsch-Gordan coefficients ofW the extension of the relativistic partial wave analysis of the two-bodyS-matrix is obtained. Scattering of particles with arbitrary masses and spins is treated and a comparison with relativistic case is discussed.
TL;DR: In this paper, the Peierls-Nabarroar barrier and the stress of edge dislocation in α-Fe at O K were calculated within the model, where the sine force law was replaced by more general force laws based on two central interionic potentials inα-Fe.
Abstract: The Peierls-Nabarro barrier and stress of thea/2〈111〉 edge dislocation on {112} and {110} plane inα-Fe at O K is calculated within the Peierls-Nabarro model. The method proposed by Nabarro is used, however, the sine force law is replaced by more general force laws based on two central interionic potentials inα-Fe. The values of the Peierls-Nabarro stress corresponding to one of the chosen interionic potentials, 3·5×10−4 μ and 1×10−4 μ on {112} plane (in the twinning direction) and on {110} plane, respectively, seem to be good estimates of the stress necessary to move edge dislocations inα-Fe at O K.
TL;DR: The densitometric patterns are reproducible and typical for a given chromosomal pair, although they display some degree of variability.
Abstract: The method of densitometric measurement of G bands on human metaphase chromosomes is described, and some factors influencing the densitometric patterns are discussed. The densitometric patterns are reproducible and typical for a given chromosomal pair, although they display some degree of variability. Typical patterns of all human metaphase chromosomes are presented, with the patterns obtained from the measurement of some structurally abnormal chromosomes (t13q14q, t14q21q, Xp-).
Journal Article•
TL;DR: Evidence is taken that only the composition of the NH2 terminus is critical for binding of the intact hormone molecule to neurophysin, provided that the N α-amino group not only is present and free but also is not sterically separated from an adjacent aromatic side chain.
Abstract: Binding studies were carried out at pH 5.8 with bovine neurophysin II and two series of analogues of lysine-vasopressin. In one series the peptide chain of the parent hormone was extended at the NH2 terminus by 1 leucine or 1 phenylalanine residue or by 1, 2, or 3 glycine residues, which represented a progressive steric separation of the Nα-amino group from the cyclic portion of the molecule. The second series of analogues consisted of shortened peptide chains at the COOH terminus, enzymatically prepared, and involved the removal of glycinamide from sequence position 9 and both terminal amino acids, lysine and glycine. Gel filtration was used to separate the neurophysin from the small peptide moieties, and spectrophotometry, dansylation analysis, and biological activity were used to investigate the fractional positions of the small peptides in the eluate. There was clear evidence of neurophysin binding of the parent hormone itself and the analogue shortened at the COOH termini. None of the analogues extended at the NH2 termini showed any binding. This is taken as evidence that only the composition of the NH2 terminus is critical for binding of the intact hormone molecule to neurophysin, provided that the Nα-amino group not only is present and free but also is not sterically separated from an adjacent aromatic side chain.