Showing papers by "Academy of Sciences of the Czech Republic published in 1983"
TL;DR: Because the six-layered placenta of the pig considerably limits transfer of maternal antibodies, the GF piglets seem to be a suitable model for the study of problems concerning the development of immunological capacity, especially in the GALT.
Abstract: The development of immunocompetency in mammals occurs during fetal life.'-3 The immunological capacity of the newborn organism, however, is not fully mature; the insufficiently adapted organism is delivered into an environment full of microorganisms. At the beginning of life the defence capacity depends to a great extent on a supply of maternal antibodies from placenta, colostrum, and milk. It is the intestinal lymphoid tissues that are exposed to the load of microflora and food antigens. The significance of microbial antigens for a clonal expansion of lymphocytes of certain idiotypes and isotypes was recently critically e ~ a l u a t e d . ~ . ~ The lymphatic tissue of the intestine reacts to antigenic stimuli by a rapid development that is particularly apparent during the first days after birth.e.7 Signs of activation of an organized lymphatic tissue (Peyer's patches, appendix) can be followed on both morphological and functional l eve l~ .~~ ' ' Later this activation is reflected in a presence of the IgMand IgA-producing cells in the intestinal mucosa.\" Cells originating in Peyer's patches and primed by intestinal antigens are supposed to migrate through the mesenteric lymph nodes, the thoracic duct and blood into the gut and other mucosal surfaces, forming the so-called common mucosal system.''-'e A similar migratory pathway as for IgA-producing cells was described for T-cells originating in the The nature of factors involved in the homing of these cells to distant mucosal surfaces and exocrine glands is still u n k n ~ w n . ' ~ ~ ' ~ In our previous studies we compared the immunological capacities of germfree (GF) piglets and rabbits with those of their conventionally raised (CONV) partners and showed that the antigenic stimulation fundamentally affects development of the immunological capa~ i ty .~ . '~ . ' ~ Nevertheless, for some other species, for example mice, the development of the immunological capacity in the GF and CONV individuals was reported to be comparable.'' We therefore inquired into the development of another available species-rat-and studied factors that affect development and recirculation of lymphocytes. Because the six-layered placenta of the pig considerably limits transfer of maternal antibodies, the GF piglets seem to be a suitable model for the study of problems concerning the development of immunological capacity, especially in the GALT. In addition, a higher weight of lymphatic organ makes easier some quantitative assays. Our experimental model was therefore used for the study of
89 citations
TL;DR: The presence of collagen type III was verified biochemically: collagen was isolated and purified from the pronase digest of osteoarthrotic cartilage, and Amino acid analyses and the CNBr peptide pattern indicated the identity of the alpha peak as alpha 1 (III).
76 citations
Journal Article•
72 citations
TL;DR: In this paper, the second-order ferroelectric phase transition in trisarcosine calcium chloride (TSCC) has been measured by use of a backward-wave oscillator in the region 2-30
Abstract: Soft modes associated with the second-order ferroelectric phase transition in tris-sarcosine calcium chloride (TSCC) have been measured by use of a backward-wave oscillator in the region 2-30 ${\mathrm{cm}}^{\ensuremath{-}1}$. A resonant mode is found in both ferroelectric and paraelectric phases. In the paraelectric ${D}_{2h}^{16} (\mathrm{Pnma})$ phase the mode decreases from 11.2 ${\mathrm{cm}}^{\ensuremath{-}1}$ at 167 K to 3.2 ${\mathrm{cm}}^{\ensuremath{-}1}$ at 130 K and yields a Curie constant of 25\ifmmode\pm\else\textpm\fi{}2 K, in reasonable agreement with low-frequency dielectric measurements. In the ferroelectric phase the mode is underdamped at most temperatures and could be measured down to 2.3 ${\mathrm{cm}}^{\ensuremath{-}1}$, at which energy it is still a resonant although overdamped excitation. These new data show that TSCC is a proper, displacive ferroelectric, with a single phase transition, contrary to earlier suggestions.
62 citations
TL;DR: In this paper, the properties of three-block copolymers poly[styrene-b-(ethene-co-butene)-b-styrene, where the middle aliphatic block amounts to about 70 wt.-%, were determined by combining the results of light scattering, small-angle X-ray scattering, photon correlation spectroscopy, osmometry, and viscometry.
Abstract: Three-block copolymers poly[styrene-b-(ethene-co-butene)-b-styrene], where the middle aliphatic block amounts to about 70 wt.-%, form micelles in 1,4-dioxane with an aliphatic core and a polystyrene shell. The basic characteristics concerning the ratio unimer/micelles, the micellar molar mass, the radius of gyration, and the hydrodynamic radius were determined by combining the results of light scattering, small-angle X-ray scattering, photon correlation spectroscopy, osmometry, and viscometry. The characteristics of the micelles, approximated by the model of concentric spheres, were calculated from the data of light scattering and small-angle X-ray scattering. From a comparison of the geometric and hydrodynamic dimensions of the micelles it follows that in dilute solutions they behave like rigid spheres.
43 citations
TL;DR: The antifeeding activities on three storage pest insects of alantolactone, isoalantlactone and ent -isoalantolactsone were measured and compared.
23 citations
TL;DR: In this paper, the rate constants of a reversible reaction in both directions are calculated by separating one of the components and measuring the velocity of its conversion to the other component of the equilibrium.
22 citations
TL;DR: In view of the results obtained in this article, the future of the SM for ZFS seems rather dim and no universally valid ¯b2(R) dependence can be constructed.
Abstract: In view of the results obtained the future of the SM for ZFS seems rather dim. Clearly, no universally valid ¯b2(R) dependence can be constructed. SM is capable to predict the signs and order of magnitudes of ZFS for a and d site S-state ions but here also a large quantitative differences may occur.
21 citations
TL;DR: Ortho and paraquinones were found to add oxidatively to the typical metal-centered radical, Co III (CN) 3− 5, producing in aprotic media radical adducts of Co(suIII) with p-semiquinone o monodentate o-semiqueinone radical ligands, respectively as mentioned in this paper.
19 citations
TL;DR: In this article, the authors measured the low lying part of hypernuclear spectra to reveal new information on the structure (deviations from the weak coupling scheme), on the NΛ effective interaction (its possible long-rangedness) and on decay mechanisms.
18 citations
TL;DR: In this article, the influence of an external electric field on the incommensurate-commensurate phase transition in K2SeO4- and (NH4)2BeF4-like crystals was studied.
Abstract: The author presents a study of the influence of an external electric field on the incommensurate-commensurate phase transition in K2SeO4- and (NH4)2BeF4-like crystals. Within the constant-amplitude approximation the same type of thermodynamic potential is found in both cases. The phase diagram in the E-T phase plane is found and should exhibit a Lifshitz point. The susceptibility of the incommensurate phase diverges at the transition point while that of the commensurate phase remains finite.
TL;DR: The possibility of quenching the fluorescence of non-phagocytosed particles enables us to distinguish clearly and reliably between internalized and cell surface-bound particles.
TL;DR: In this article, the orientation relationship between the primary recrystallization texture and the large secondary grains grown during unidirectional annealing of heavily deformed nickel was confirmed.
TL;DR: Electron paramagnetic resonance spectra revealed the formation of a +4V - bleomycin complex which is still able to activate the (Na+-K+) ATPase.
TL;DR: In this paper, the Xα-SW method is employed to deduce estimates of the differences in the electron densities at the Te nucleus in some compounds, and some assertions are deduced to the calibration problem of the Mossbauer nuclide125Te and to the chemical influence on the IC of the 35.5 keV M1+E2 transition in125Te.
Abstract: This paper reports results of a study in which the Xα-SW method is employed to deduce estimates of the differences in the electron densities at the Te nucleus in some compounds. On the basis of these estimates some assertions are deduced to the calibration problem of the Mossbauer nuclide125Te and to the chemical influence on the IC of the 35.5 keV M1+E2 transition in125Te.
TL;DR: In this paper, a series of retinas from 30 human embryos, ranging in total length from 10 to 40 mm, were successfully stained by the Golgi method and then examined and compared with routinely stained specimens from pertinent stages.
Abstract: A series of retinas from 30 human embryos, ranging in total length from 10 to 40 mm (i.e., to the end of gestation month 2), were successfully stained by the Golgi method and then examined and compared with routinely stained specimens from pertinent stages. Two more series impregnated with other silver methods were used as controls. In the results we try to clarify some difficult points in the literature on the subject.
TL;DR: In this paper, a boundary condition was incorporated into the Thomas-Fermi approximation for systems with finite surface barriers and the modified procedures for the determination of the charge density were tested on the image-type model potential corresponding to the bent bands at surfaces of semimetals or highly doped semiconductors.
Abstract: Incorporation of a boundary condition into the Thomas-Fermi approximation is generalized for systems with finite surface barriers. The standard and the modified procedures for the determination of the charge density are tested on the image-type model potential corresponding to the bent bands at surfaces of semimetals or highly doped semiconductors. Substantial improvement of the description of the electron charge density is achieved in the modified Thomas-Fermi approximation.
Die Einarbeitung einer Randbedingung in die Thomas-Fermi-Naherung wird fur ein System mit endlicher Oberflachenbarriere verallgemeinert. Das modifizierte Verfahren zur Bestimmung der Ladungsdichte wird mit dem Standardverfahren fur ein Modellpotential vom Spiegelladungstyp verglichen, das der Bandverbiegung an der Oberflache von Halbmetallen und entarteten Halbleitern entspricht. Bei der Beschreibung der Elektronendichte wird durch die modifizierte Thomas-Fermi-Naherung gegenuber dem Standardverfahren eine wesentliche Verbesserung erreicht.
TL;DR: In this article, the authors present a theory of the crystal growth from melt, which makes it possible to model the growth and calculate the function v(t), at the same time it is not necessary to look for the conditions of the stability of the solidification front, or to restrict models to the states near the thermodynamic equilibrium or to the stationary growth.
Abstract: The presented results are in agreement with the real processes connected with the crystal growth from melt; this proves the correctness of our theory. In conclusion let us summarize the basic properties and priority of our theory. This theory makes it possible to model the crystal growth and to calculate the function v(t); at the same time it is not necessary to look for the conditions of the stability of the solidification front, or to restrict models to the states near the thermodynamical equilibrium or to the stationary growth. The heat conduction equation can be solved without imposing assumption on the temperature at the interface. Our model makes it possible to connect the kinetic processes at the solidification front with the heat or mass transport. The fluctuations of the interface are included in our model. This description accords with real processes. On the other hand, it is necessary to estimate the imperfections of our model. The flow of the melt, the structure of the solidification front, etc. are not taken into account. Some approximations are quite rough and we cannot omit the pretensions to the computer time, either. In spite of these imperfections we suppose that this theory will be suitable for the study of the crystal growth (the course of the crystal growth, the stability of the solidification front, the influence of external conditions, external fields or cooling, etc.), or for optimizing the technology of growth of the special materials.
TL;DR: In this article, the thermally stimulated processes in the x -irradiated LiNbO 3 crystals were studied by the fractional glow technique, and the trap ionization with unusually high values of the mean activation energy and the effective frequency factor as well as decreasing the activation energy of the traps when the temperature increased from 150-180 K were observed.
TL;DR: In this article, the authors connect the kinetic processes at the solidification front with the heat transport, making it possible to observe influence of both external conditions and properties of a material or phase transition on the process of crystal growth in the framework of one theory only.
Abstract: As we have pointed out in part I, our model makes it possible to connect the kinetic processes at the solidification front with the heat transport. This connection of both approaches makes it possible to observe influence of both external conditions and properties of a material or phase transition on the process of crystal growth in the framework of one theory only.
TL;DR: In this paper, several electronic circuits were constructed and tested for use in the body of ion-selective electrodes to convert the high-impedance output signal to a low-IMpedance one, in order to improve the signal-to-noise ratio.
TL;DR: For the metal dichalcogenides SnS 2 and MoS 2 the angular dependent K emission bands of sulphur were measured and calculated for take-off angles 15° and 70°.
01 Sep 1983-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, a mathematical formulation was developed to represent the heat transfer and the solidification process in a drum and ring type horizontal strip casting machine, which involves a ring shaped trough, containing a molten metal pool into which a drum is partially immersed.
Abstract: A mathematical formulation has been developed to represent the heat transfer and the solidification process in a drum and ring type horizontal strip casting machine. This system involves a ring shaped trough, containing a molten metal pool into which a drum is partially immersed. Both the ring and the drum are made to rotate and their surfaces are cooled with water sprays; as a result, solidified shells are formed on both the internal surface of the ring and on the outer surface of the drum. These two shells are welded together to form the strip. In the formulation equations were developed to represent the temperature profiles in the system and the build-up of the solidified shells as a function of position. The principal usefulness of the analysis is to provide guidance regarding the interrelationships between the key process variables, such as the depth of the metal pool, the system geometry, the angular velocities, and heat transfer coefficients. One may also define the safe limits of operation, in terms of these parameters.
TL;DR: Etude de la partie angulaire de la probabilite de transition dipolaire RX as mentioned in this paper, on donne la relation entre les etats s,p de cœur, les ETats de valence p x, p y, p z, d ze, d xz, d yz, D xy et d x2−y2 et la polarisation u
Abstract: Etude de la partie angulaire de la probabilite de transition dipolaire RX. On donne la relation entre les etats s,p de cœur, les etats de valence p x , p y , p z , d ze , d xz , d yz , d xy et d x2−y2 et la polarisation u
TL;DR: The data support the view of no relationship between the development of metabolic changes and the established arthritic lesions in rats and that the defects in metabolism of drugs, following bacterial-adjuvant treatment, are likely to be due to some additional cell-wall components, other than peptidoglycans.
TL;DR: Correlation effects in disordered transition metal alloys are studied within the degenerated Hubbard model using the perturbation theory limited to the second order in U/w (U Coulomb integral, w bandwidth) as mentioned in this paper.
Abstract: Correlation effects in disordered transition metal alloys are studied within the degenerated Hubbard model using the perturbation theory limited to the second order in U/w (U Coulomb integral, w bandwidth). The influence of disorder is included within the coherent potential approximation. The theory is illustrated on a simple model of the copper–nickel alloy.
Korrelationseffekte in ungeordneten Legierungen von Ubergangsmetallen werden im Rahmen eines entarteten Hubbard-Models mit Hilfe der Storungstheorie zweiter Ordnung in U/w untersucht (U Coulomb Integral, w Bandbreite). Der Einflus der Fehlordnung wird durch die Naherung des koharenten Potentials einbezogen. Die Theorie wird fur ein einfaches Modell der Kupfer–Nickel-Legierung dargestellt.
TL;DR: In this article, the authors show that the surface anchoring energy for both ferroelectric and paralelectric state of TGS can be estimated within the limits 10−6−7×10−7 J/m2.
Abstract: 1)
The domains of different contrast in NLC over the ferroelectric domains of TGS are encircled by the surface twist disclination lines with the strengthsσ1=58/360 andσ2=1/2-58/360.
2)
During the phase transition of TGS from ferroelectric to paralelectric state the surface of TGS starts to be uniform and thus theσ1-line disappears and theσ2-line transforms to theπ-twist disclination line.
3)
The value of the surface anchoring energy for both ferroelectric and paraelectric state of TGS can be estimated to be within the limits 10−6−7×10−7 J/m2.
TL;DR: The two-band model described here, based on the parabolic dispersion law and elastic scattering approximation is capable to explain many aspects of the Shubnikovde Haas effect, although the elastic scattering approximation is not suitable for the experiments mentioned.
Abstract: The two-band model described here, based on the parabolic dispersion law and elastic scattering approximation is capable to explain many aspects of the Shubnikovde Haas effect, although the elastic scattering approximation is not suitable for ail experiments mentioned. We have satisfactorily explained the phase shift between oscillations of different components of the resistivity tensor. The oscillation amplitude of the longitudinal magnetoresistance Bi can also be well fitted. These effects have been interpreted by authors of the experiments [2, 3] in another way, based on the assumption of dominant contribution of inter-level scattering. They obtain a worse fit and also their Dingle temperatureT
D=15 K is less realistic thanT
D=3 K suitable for the fitting presented in section 5b of this paper. It has also been shown that the oscillation amplitude of the transverse and nondiagonal (Hall) components of the resistivity is strongly affected by the difference between the numbers of electrons and holes. This effect might also be responsible for the large enhancement of the oscillation amplitude due to alloying in Bi, doped with Sb [1], as in available samples the precise compensation is usually not achieved.