Showing papers by "Czechoslovak Academy of Sciences published in 1980"
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01 Jan 1980TL;DR: The replacement of the classical transfer-function approach by the state-space approach was one of the major developments in the theory of multivariable control systems.
Abstract: The replacement of the classical transfer-function approach (which has been proved natural and effective in many practical cases) by the state-space approach was one of the major developments in the theory of multivariable control systems.
437 citations
TL;DR: The Galvani potential difference at the interface of two immiscible electrolyte solutions (ITIES), Δ α βϕ, can be determined, when concentrations, activity coefficients, standard Gibbs transfer energies of all ions, which are present in the system, volumes of each phase and temperature are known as discussed by the authors.
143 citations
TL;DR: In this paper, high-resolution infrared spectra have been remeasured for the 2.5 GHz and 3 GHz bands of /sup 14/NH/sub 3/ using a vacuum grating infrared spectrometer and a diode laser spectrometers.
135 citations
TL;DR: C Coulometric measurements showed that oxidation of tyrosine and tryptophan at the WISGE, i.e. of amino acids which are responsible for the oxidizability of proteins at graphite electrodes, is a two-electron process.
130 citations
TL;DR: This article demonstrates the application of least squares for the estimation of system parameters and solutions are discussed for the case of white noise and correlated noise corrupting the useful output signal of the system.
123 citations
TL;DR: This article showed that cyclization plays a decisive role already at the onset of the reaction and observed an apparent decrease in reactivity of the pendant double bonds in the interior of the chain.
Abstract: Analysis of experimental results on the chain (co) polymerization of bisunsaturated monomers suggests that cyclization plays a decisive role already at the onset of the reaction. At medium and elevated concentrations of the bisunsaturated compound, compact microgel-like particles are formed, which give rise to a gel mainly by participating in the polymerization reaction only with pendant double bonds in their surface layer, and not with double bonds in the interior. This mechanism is reflected in an apparent decrease in reactivity of the pendant double bonds.
103 citations
TL;DR: It is concluded that elastin contains several fluorophores, one of which is a cross-linking tricarboxylic amino acid with a pyridinium ring having very probably the structure of 3-(2-amino-2-carboxyethyl)-1-(5-aminino-5- carboxy- 2-hydroxy-pentyl)-5-hydroxypyrid inium.
98 citations
TL;DR: In this article, it was found by analysis of the composition and n.m.r. behavior of low-conversion soluble copolymers of styrene (S) with 5-60 wt% of ethylene dimethacrylate (EDMA) that cyclization strongly predominates in crosslinking copolymerization.
97 citations
TL;DR: The method of nondiscrete mathematical induction is applied to the Newton process and yields a very simple proof of the convergence and sharp apriori estimates.
Abstract: The method of nondiscrete mathematical induction is applied to the Newton process. The method yields a very simple proof of the convergence and sharp apriori estimates; it also gives aposteriori bounds which are, in general, better than those given in [1].
91 citations
TL;DR: It was found that adenine, guanine, hypoxanthine, 8-hydroxyadenine, and a number of further purine derivatives react in alkaline media with mercury of the electrode charged to potentials close to zero V and form sparingly soluble compounds.
88 citations
TL;DR: It was shown that irreversible electrooxidation of tyrosine or tryptophan residues is responsible for the occurrence of these protein currents and it was demonstrated that voltammetry at graphite electrodes permits an electrochemical analysis of proteins that do not contain cystine or cysteine residues.
TL;DR: Nicotianamine has an optimal molecular structure for chelating iron ions and is considered a possible phytosiderophore with an essential function in cellular iron transport and/or metabolism.
TL;DR: It was shown that -Phe-Lys- was the most suitable -X-Y- sequence and extension of the oligopeptidic sequence by one amino acid residue causes a pronounced rise in the rate of cleavage of the polymeric substrates.
TL;DR: In this paper, it was shown that every finite lattice is isomorphic to the congruence lattice of a finite algebra if and only if every finite algebraic lattice can be characterized by an interval in the subgroup lattice.
Abstract: I t is well-known that every algebraic lattice is isomorphic to the congruence lattice of an algebra. In this pape r we are interested in the prob lem of characterizing the finite lattices, which are isomorphic to the congruence lattices of finite algebras. We are not able to settle the prob lem if every finite lattice is isomorphic to the congruence lattice of a finite algebra (cf. [1], Problem 13). Our main result shows that this problem is related to the prob lem to characterize intervals in subgroup lattices of finite groups. Namely, every finite lattice is isomorphic to the congruence lattice of a finite algebra if and only if every finite lattice is isomorphic to an interval in the subgroup lattice of a finite group.
TL;DR: In this paper, a method of selenium hydride atomization using a cool highly fuel rich-hydrogen-oxygen diffusion flame burning in the inlet part of a T-shaped quartz tube placed in the optical axis of an atomic absorption spectrometer is investigated.
TL;DR: In this paper, a modified theory is worked out for the Δk = ±3n interactions between the inversion-rotation energy levels of NH3 which takes into account the large amplitude inversion motion.
TL;DR: A series of twenty two N-(2-hydroxypropyl) methacrylamide copolymers, each containing a different, potentially degradable side chain, were incubated with rat liver Tritosomes and four of the side chains were digestible as judged by the liberation of a terminal 4-nitroaniline residue.
TL;DR: In this paper, the authors used aminopropyl-silica gel in the sulphate form and water-acetonitrile (20:80) as the mobile phase for the separation of oligosaccharides.
01 Jan 1980
TL;DR: In this paper, the most important classes of phenolic antioxidants for the conditions of inhibited oxidation were reviewed with respect to the long-term properties of polyolefins and properties and importance of the main types of formed products.
Abstract: Transformation mechanisms of the most important classes of phenolic antioxidants are given for the conditions of inhibited oxidation. Properties and importance of the main types of formed products are reviewed with respect to the long-term properties of polyolefins.
TL;DR: In both types of tissue reaction, the spores are destroyed by complete digestion within host phagocytic cells, and the extent of pathological changes probably depends on the ability of early developmental stages of the parasite to spread the infection within the host.
Abstract: . Histopathological studies on natural and experimental infections of nineteen microsporidian species from fishes distinguished two types of tissue reactions.
The first type is characteristic of infections with xenoma-inducing microsporidian species and comprises three successive stages: a weakly reactive stage, a productive stage with the formation of granulomas and a stage of granuloma involution. Following the first stage, tissue reactions are directed towards the isolation of the parasite and result in its complete elimination and host tissue repair. The extent of pathological changes probably depends on the number of parasite cells which initiated the infection.
The second type is represented by Pleistophora species infecting muscles or oocytes. Host tissue reaction is surprisingly slight during the schizogony and sporogony and does not tend to isolate the invaded muscle fibres. A slight lymphocytic infiltration of myosepta indicates the first stage of tissue reaction. The tissue reaction only reaches the productive stage when mature spores completely fill the contents of the infected muscle fibre. A thick wall of fibroblasts may be formed to demarcate the parasite mass as soon as it undergoes necrotic changes. The extent of pathological changes probably depends on the ability of early developmental stages of the parasite to spread the infection within the host.
In both types of tissue reaction, the spores are destroyed by complete digestion within host phagocytic cells.
TL;DR: It is concluded that, at least within the isolated frog spinal cord, K + accumulation is a significant factor modifying transmission following dorsal root tetanic stimulation and that its distribution is inhomogeneous.
TL;DR: It is concluded that the blockade of handedness produced by unilateral 6-OHDA lesions of substantia nigra is not due to paralysis of the forelimb but to faulty integration of the contralateral somatosensory signals withcontralateral motor patterns.
Abstract: Unilateral 6-hydroxydopamine (6-OHDA) injections into the nigrostriatal system of rats were used to interfere with a lateralized reaching-for-food habit, the so-called “handedness.” Experiment 1: Although injections of 6-OHDA into the substantia nigra (8 µg/4 µl) ipsilateral (n=7) to the preferred forelimb had no effect on the overlearned instrumental reaction, reaching was blocked 15 min after contralateral (n=12) injection of the neurotoxin and remained suppressed for the 8 days of testing. At the same time, retrieval of food with the nonpreferred forepaw significantly increased. Although the rats failed to reach into the feeder, behaviors like grasping, grooming, or holding food pellets were intact in the “neglected” forepaw. Nonspecific effects such as changes in activity level or motivation could be ruled out by the ipsilateral-contralateral test paradigm used. The early behavioral asymmetries (blockade of handedness, flexion of the forelimb, and ipsilateral turning) are interpreted as due to interference of 6-OHDA with membrane structures of dopaminergic neurons. Experiment 2: Injections of 6-OHDA into the caudate nucleus contralateral (30 µg/5 µl, n=9) to the performing forelimb initially blocked handedness similarly as in Experiment 1. However, in contrast to nigral injections, reaching recovered within 6 days. Experiment 3: One month after a unilateral 6-OHDA lesion of substantia nigra, naive rats (n=7) acquired the reaching-for-food habit with the paw ipsilateral to the lesion. It is concluded that the blockade of handedness produced by unilateral 6-OHDA lesions of substantia nigra is not due to paralysis of the forelimb but to faulty integration of the contralateral somatosensory signals with contralateral motor patterns.
TL;DR: By combining thermal treatment and extraction of aluminium with hydrochloric acid, the authors succeeded in reducing the content of A1 atoms in Zeolite Y from 57 to 5 per elementary cell, without destroying the faujasite structure.
TL;DR: In this paper, the problem of tracking a reference variable from a given class is considered for discrete-time linear single-input-output plants, where the plant and the reference are both described by an input/output relation, such as a difference equation, and the objective is to track exactly in a minimum time.
Abstract: The problem of tracking a reference variable from a given class is considered for discrete-time linear single-input-output plants. The plant and the reference are both described by an input/output relation, such as a difference equation, and the objective is to track exactly in a minimum time. This dead-beat servo problem is solved hero by applying polynomial techniques. The optimal control law is shown to contain both feed-back and feed-forward terms and it is obtained by solving two linear polynomial equations. The entire design procedure is remarkably simple and efficient.
TL;DR: In this article, the ionization probability of an atomic particle sputtered from a simple substrate system has been analyzed with use of a computer simulation of the sputtering process and a Boltzmann-like functional form was defined.
Abstract: The ionization probability of an atomic particle sputtered from a simple substrate system has been analyzed with use of a computer simulation of the sputtering process. The ionization probability was found to have a Boltzmann-like functional form and a quantity called "the effective temperature" ${T}_{e}$ could be defined. The value of ${T}_{e}$ was found to be in the range of 2000-3500 K. The dependence of ${T}_{e}$ on the microscopic parameters of the system has been investigated.
TL;DR: The dynamics of the onset and offset of blocking suggests that SD propagation is prevented by enhanced K+ reabsorption which rapidly removes the K+ ions penetrating the stimulated area from the SD wave front.
TL;DR: The effect of vanadate on malate dehydrogenase (MDH, EC1.1.37) catalysed oxidation of NADH during the formation of malate from oxalacetate in vitro and it was found thatVanadate does not require the presence of any specific enzyme or substrate to mediate NADH oxidation.
Abstract: It has recently been found that ortho- or metavanadate can effectively block (Na+ + K+) ATPase1–4 and that it loses its blocking potency when reduced to the vanadyl (VO2+) ion5. The question arose whether vanadate could be involved (reduced) in an NAD-linked enzymatic redox system of the cell. Here we have studied the effect of vanadate on malate dehydrogenase (MDH, EC1.1.1.37) catalysed oxidation of NADH during the formation of malate from oxalacetate in vitro. The MDH reaction was accelerated by vanadate, but we found that vanadate does not require the presence of any specific enzyme or substrate to mediate NADH oxidation.