Showing papers by "Hungarian Academy of Sciences published in 1969"
TL;DR: In this article, it is suggested that force constants should be calculated by differentiating the forces numerically, which is numerically more accurate and requires less computation than the customary one of differentiating energy numerically twice.
Abstract: The general expression for the exact forces on the nuclei (negative derivatives of the total energy with respect to the nuclear coordinates) is applied for Hartree-Fock wavefunctions. It is suggested that force constants should be calculated by differentiating the forces numerically. This method, called the force method, is numerically more accurate and requires less computation than the customary one of differentiating the energy numerically twice. It permits the quick determination of the equilibrium geometry by relaxing the nuclear coordinates until the forces vanish. The unreliability of the methods using the Hellmann-Feynman forces is re-emphasized. The question of which force constants can be best calculated ab initio is discussed.
2,106 citations
TL;DR: This chapter is dedicated to describing citrate synthase, which can be followed by measuring the appearance of the free SH group of the released CoASH through three methods discussed in the chapter.
Abstract: Publisher Summary This chapter is dedicated to describing citrate synthase. The assay of citrate synthase is performed by coupling it to the transacetylase reaction. The disappearance of acetyl phosphate is followed by a hydroxamate method and the formation of citrate by the pentabromoacetone method. The malate dehydrogenase catalyzed reaction is used to generate the oxaloacetate for the citrate synthase reaction. Another method for assaying citrate synthase uses 14 C-acetyl-CoA and measures its incorporation in 14 C-citrate, which is isolated as a silver salt. Citrate synthase can be followed by measuring the appearance of the free SH group of the released CoASH; three such methods are discussed in the chapter. One method is to measure the oxidation of the CoASH by dichlorophenol- indophenol, which is accompanied by a decrease in absorbancy at 578 mμ. Another method measures the CoASH polarographically. The third method measures SH by the use of 5, 5’-dithiobis-(2-nitrobenzoate) (DTNB) (Ellman's reagent).
1,848 citations
TL;DR: In this paper, the formation of vacuum-deposited In thin films was studied by in situ electron microscopy, and a preferred orientation was found to develop at a given crystallite size depending on the substrate temperature and the ratio of impinging oxygen molecules to film atoms.
Abstract: The formation of vacuum-deposited In thin films was studied by in situ electron microscopy. The dependence of melting point and crystallization temperature on particle size was measured. A preferred orientation was found to develop at a given crystallite size depending on the substrate temperature and on the ratio of impinging oxygen molecules to film atoms (K factor).
99 citations
99 citations
TL;DR: In this article, Park vectors are used to predict the waveforms of inverter quantities under various load conditions, such as passive R-L and R-C loads, and the current distribution of the inverter can be obtained from the current vector.
Abstract: A method of analysis for three-phase inverters is described. The method is based on Park vectors [1], [2] and predicts the waveforms of inverter quantities under various load conditions. The procedure discussed can be used to determine the commutation sequence of a pulsewidth modulated inverter. The current distribution of the inverter can be obtained from the current vector. The vectors of the inverter voltage and currents are determined for passive R-L and R-C loads. Oscillograms of the current vectors are shown for different loads.
54 citations
52 citations
TL;DR: A simple proof of a version of the noiseless coding theorem is given, based on the properties of entropy and avoiding combinatorial arguments; also, in the familiar proof of the mentioned theorem, a possible simplification is pointed out.
Abstract: Shannon's capacity formula for memoryless and finite-state noiseless channels is proved in a simple elementary way, for arbitrary symbol costs; actually, a somewhat stronger result is proved. Further, a simple proof of a version of the noiseless coding theorem is given, based on the properties of entropy and avoiding combinatorial arguments; also, in the familiar proof of the mentioned theorem, a possible simplification is pointed out. Finally, a nearly optimal encoding for finite-state noiseless channels is suggested.
50 citations
TL;DR: Evidence is presented that thiol-subtilisin but not subtilisin may contain a hydrogen bond, and a rigid active site model for the serine proteases is proposed in which the histidine residue operates in a fixed steric position both as a general base and as ageneral acid.
Abstract: The high reactivity of the serine residue at the active site of serine proteases is often attributed to the formation of a hydrogen bond between this serine and a histidine residue. In the case of the serine protease subtilisin, the catalytic serine residue can be specifically replaced by a cysteine residue and this modified enzyme is called thiol-subtilisin. By studying the D2O effect on acyl-enzyme formation with subtilisin and thiol-subtilisin, we present evidence that thiol-subtilisin but not subtilisin may contain a hydrogen bond. Based on the comparison of the catalytic activities of subtilisin and thiol-subtilisin, a rigid active site model for the serine proteases is proposed in which the histidine residue operates in a fixed steric position both as a general base and as a general acid, and this, rather than the formation of a hydrogen bond, accounts for the high nucleophilicity of the serine residue.
49 citations
01 Jan 1969
TL;DR: Some hitherto poorly considered problems of linguistic theory are explored and some concepts that might be useful for further and more detailed investigations are stipulated that may shed new light on certain properties of lexical readings and lexical systems of natural languages in general.
Abstract: At first glance the problem of definitions in natural language seems to be a more or less marginal question. This is, however, far from being true. While discussing definitions we shall be forced to touch upon some fairly intricate and central problems of linguistic theory. Though even the formal properties of definitional sentences are far from being clear, the more difficult problems arise with respect to their semantic interpretation, their role in introducing new terms into a given language, and their relation to non-definitional generic sentences. Questions of this type may shed new light on certain properties of lexical readings and lexical systems of natural languages in general and on the relation between analytic and empirical generic sentences based on these properties in particular. We cannot answer these questions within the limits of the present article. We only intend to explore some hitherto poorly considered problems of linguistic theory and to stipulate some concepts that might be useful for further and more detailed investigations.
31 citations
29 citations
TL;DR: In this paper, the Coulomb and effective attractive terms for the polycytosine homopoly-nucleotide were calculated for many intraband and interband scattering processes, and the absolute value of the attractive term is larger than, or about the same as, that of Coulomb term.
Abstract: Applying Little's formalism to investigate the possibility of superconductive regions at room temperature in organic polymers, we have calculated the Coulomb and effective attractive terms for the polycytosine homopoly-nucleotide. Little's original idea that the effective interaction between the mobile electrons of the spine is due to the polarization of the side-chain electrons has been extended to take into account the polarization of the σ electrons of the same systems which provide the mobile electrons.
According to the results obtained for many intraband and interband scattering processes, the absolute value of the attractive term is larger than, or about the same as, that of the Coulomb term. Therefore, we cannot exclude the possibility of superconductive-type enhanced conductivity in some regions of DNA. Finally, the effects of the finite dimensions of a cytosine molecule are discussed from the point of view of screening and thermodynamic fluctuations.
TL;DR: This paper proves infinitary analogues of model-theoretic results known for finitary logic of L., and extends to a wide class of sublanguages (includingfinitary logic) of L, thus providing a unified treatment of a number of results for these languages.
Abstract: In this paper we prove infinitary analogues of model-theoretic results known for finitary logic. The infinitary language we deal with is Lω1ω which is roughly described by saying that, in addition to the usual formation rules of the lower predicate calculus with identity, also the formation of the conjunction and disjunction of countably many formulas is allowed.
TL;DR: In this paper, basic principles of a possibility of simplifying the spin-projected Hartree-Fock equations by means of the method of moments have been outlined, and a method of moment-based method of simplification is proposed.
Abstract: Basic principles of a possibility of simplifying the unrestricted spin-projected Hartree-Fock equations by means of the method of moments are outlined.
TL;DR: In this article, the band structures of the periodic DNA models poly (A-T) and poly(G-C) were calculated in the semi-empirical SCF LCAO Pariser-Parr-Pople crystal orbital approximation.
01 Jan 1969
TL;DR: In this article, the uranium content of Hungarian coals was discovered by the senior author in 1949 and very soon confirmed by observations on coals in many parts of the world, and the accumulation can be characterized by a very high geochemical enrichment factor of 10,000:1.
Abstract: V.M. Goldschmidt observed in the thirties high geochemical accumulation of microelements in coals. He assumed three possible explanations for them. He missed the uranium accumulation in coals, because spectral analytical technique is not sensitive for U. U content of Hungarian coals was discovered by the senior author in 1949 and very soon confirmed by observations on coals in many parts of the world. Experiments of the senior author clarified the cause of this accumulation. U is accumulated from very dilute solutions by the cation exchange properties of insoluble humic acids in peat. The accumulation can be characterized by a very high geochemical enrichment factor (GEF) of 10,000:1.
TL;DR: Constriction of the pancreatic arteries and arterioles was observed, the blood capillaries failed to fill, existing arteriovenous shunts widened and new ones arose, and venous stasis developed in dogs induced by an injection of bile through the duct of Santorini haemorrhagic pancreatitis.
Abstract: By an injection of bile through the duct of Santorini haemorrhagic pancreatitis was induced in dogs. Three and 24 hours after the injection, the pancreatic vascular system was filled up through the superior pancreaticoduodenal artery, and in some cases also through the corresponding vein, with 5 % polyvinyl chloride or 3 % Indian ink-gelatin. Constriction of the pancreatic arteries and arterioles was observed, the blood capillaries failed to fill, existing arteriovenous shunts widened and new ones arose, and venous stasis developed. These lesions are supposed be the result of compression by pancreatic oedema and of nervous stimulation.
TL;DR: In this article, it was shown that Lindelof's conjecture implies that N(α, T) = O(Tϵ) for α ≥ 3 4 + δ (ϵ, δ > 0, arbitrarily small).
TL;DR: In this article, the kinetics of the overall process of the thermal degradation of dissolved poly(vinyl chloride), taking place under oxygen-free conditions, have been studied, and the kinetic treatment of the process has been accomplished, based on the assumption of special polymer sequences.
TL;DR: The nickel catalyst complex probably contains both σ-alkyl (aralkyl or aryl) and π-olefin ligands, and direct hydride migration between these ligands is proposed as the mechanism for the exchange and isomerization in the presence of certain olefins.
01 Jan 1969
TL;DR: This paper outlines the proof of the upper bound of (1), a simple lemma states that every integer msx can be written in the form u-v where u is either a prime or is more than x 2/3 and v is less than x2/3.
Abstract: The problems which we will discuss in this paper deal with sequences of integers: they are all of a combinatorial nature and graph theoretic results can be applied to some of them. First we define the concept of an r-graph (for r=2 we obtain the ordinary graphs). The elements of the r-graph are its vertices some of whose r-tuples belong to our r-graph. Gr(n, t) denotes an r-graph of n vertices and t r-tuples. Gr(n; (F)) denotes the complete r-graph Kr(n) and Kr(pl,. .. . P,) denotes the r-graph of (p, +. .. + p,) vertices with pi vertices of the i-th class where each r-tuple all whose vertices are in different classes belongs to our Kr(pl, .-., p,). Throughout this paper, "graph" will indicate a 2-graph. We will denote 2-graphs by G (i.e., in G2 the index 2 will be omitted). It is well known and easy to see that if ap i. .. c: ak < n and no a# Also if we 1 divides any other a. 7 then max k = t-1. assume that no ai divides the product of ail the other a. s we J can easily show that max k = n(n). The same result holds if we ask sume that all the products i7 a.cui i=l ' are distinct (the ai's being non-negative integers). Let us now assume that our sequence has the property that no ai divides the product of two other a.'~. I proved [3] that in this case 7 (1) II(x) + Cl x 2'3/(log x)2 < max k < n(x) + c2 x 2'3/(log x) 2. We outline the proof of the upper bound of (1). A simple lemma states that every integer msx can be written in the form u-v where u is either a prime or is less than x 2/3 and v is less than x 2/3. Corresponding to the sequence al <. .. < ak we form a graph as follows: The vertices of our graph are the integers < x 2/3 and the primes p, x 213
TL;DR: In this article, paramagnetic H 2 Co(PPh 3 ) 3 and Co(N 2 ) (PPh3 ) 3 were prepared from cobaltous acetylacetonate and diethyl aluminium ethoxide in H 2 or N 2 atmosphere, respectively.
TL;DR: Es wurde gezeigt, dass im Procerebrum der Gastropoden axosomatische Synapsen von 2 Typen vorkommen.
Abstract: Es wurde gezeigt, dass im Procerebrum der Gastropoden axosomatische Synapsen von 2 Typen vorkommen. Diese Befunde sind ungewohnlich, da axosomatische Synapsen in anderen Teilen des Zentralnervensystems nicht existieren.
TL;DR: In this article, the diagonal and off-diagonal polarizability tensor elements of the nucleotide bases and base pairs were calculated and the components of the permanent dipole moments were computed for these systems.
Abstract: Generalizing the method of Hirschfelder, Curtiss and Bird for the calculation of the polarizability of molecules, we have calculated both the diagonal and off-diagonal polarizability tensor elements of the nucleotide bases and base pairs. In the course of calculations also the components of the permanent dipole moments have been computed for these systems.
On the basis of the results obtained we have determined also the critical field strengths necessary to break off a base pair and thus to induce the unwinding of the DNA double helix. According to the data obtained, a field strength of the order 108 V/cm can induce the unwinding of DNA if its direction lies in the plane of the base pairs.
TL;DR: In rats, prolonged administration of haloperidol for 2 to 3 months failed to affect cataleptogenic activity, diminished the potentiating effect on pentobarbital narcosis, and had no influence on the inhibition of amphetamine-induced stereotypy.
Abstract: The chronic administration of haloperidol to mice over periods of 1 week to 3 weeks has been shown not to decrease the anti-amphetamine properties of the compound, as measured by determining group toxicity and the inhibition of enhanced metabolic rate; on the other hand, the cataleptogenic effect of the drug slightly and transiently decreased after long-term treatment, the potentiation of pentobarbital narcosis being markedly reduced.
TL;DR: In this paper, an experimental study of the IB spectrum from 32P was carried out for the clarification of the contradictions among the various experimental investigations, based on a critical analysis of the measuring conditions and the evaluation process.
TL;DR: Early in 1966 antibodies to influenza B virus in stocks of swine which had been affected by an influenza-like disease late in 1965, during, or immediately after, an influenza B epidemic were demonstrated.
Abstract: EARLY in 1966 we demonstrated antibodies to influenza B virus in stocks of swine which had been affected by an influenza-like disease late in 1965, during, or immediately after, an influenza B epidemic1 Piglets were inoculated intranasally with an early egg passage of an influenza B strain isolated from the 1965 epidemic An inoculated piglet developed specific antibodies, a contact piglet gave an equivocal response In the more extensive study reported here, experimental conditions were carefully controlled to give unequivocal results
TL;DR: A detailed survey of the parameter representation of force constants is given in this paper, which permits the force constants compatible with the measured frequencies to be calculated in order to establish the assignment and to find the force constant matrix F belonging to the centre of an assignment.