Showing papers by "Russian Academy of Sciences published in 1987"
TL;DR: In this article, a deuterium profile along the 160,000-year Vostok ice core (Antarctica) is interpreted in terms of atmospheric temperature changes, which is the awaited terrestrial complement of the deep-sea records supporting the existence of a relation between the Pleistocene climate and orbital forcing.
Abstract: A continuous deuterium profile along the 160,000-year Vostok ice core (Antarctica) is interpreted in terms of atmospheric temperature changes. This climatic record is the awaited terrestrial complement of the deep-sea records supporting the existence of a relation between the Pleistocene climate and orbital forcing.
848 citations
TL;DR: Experimental evidence on the existence of the novel “molten globule” state of the protein molecule and its role in protein folding are compared with the sequential model of protein folding proposed by the author in 1972–1973.
Abstract: The current state of the problem of protein folding is reviewed with special attention to the novel “molten globule” state of the protein molecule, intermediate between the native and unfolded states. Experimental evidence on the existence of this state and its role in protein folding are compared with the sequential model of protein folding proposed by the author in 1972–1973.
534 citations
TL;DR: In this paper, the authors proposed a new scenario of the baryon asymmetry generation in the framework of standard electroweak theory which is based on the recent observation that anomalous Baryon number violating processes are nonsuppressed at high temperatures.
519 citations
TL;DR: It is concluded that "laser biostimulation" is of aPhotobiological nature, and low-power laser effects can be related to well-known photobiological phenomena.
Abstract: Quantitative studies of the action of low-power visible monochromatic light on various cells (E. coli, yeasts, HeLa) were performed to find irradiation conditions (wavelength, dose, intensity) conducive to vital activity stimulation. The action spectra of visible light on DNA and RNA synthesis in HeLa cells have maxima near 404, 620, 680, 760, and 830 nm. Growth simulation of E. coli is at a maximum when irradiated at 404, 454, 570, 620, and 750 nm, and biomass accumulation stimulation in yeasts has a maxima at 404, 570, 620, 680, and 760 nm. Absorption of quanta is only a trigger for the rearrangement of cellular metabolism, with photosignal transduction being effected by standard cellular means such as changes in the cAMP level. Respiratory chain components are discussed as primary photoacceptors. It is concluded that "laser biostimulation" is of a photobiological nature, and low-power laser effects can be related to well-known photobiological phenomena.
518 citations
TL;DR: Evidence is presented that the H form is the structural basis for Sl-nuclease hypersensitivity and can arise in any homopurine-homopyrimidine mirror repeat (H palindrome)3.
Abstract: Regular homopurine-homopyrimidine tracts, (dG-dA)n(dT-dC)n and (dG)n(dC)n, undergo a superhelix-induced, strongly pH-dependent, structural transition into a novel DNA conformation, the H form. We have suggested that the H form can arise in any homopurine-homopyrimidine mirror repeat (H palindrome). We have now tested this prediction using a tailored series of plasmids carrying the inserts AAGGGAGAAXGGGGTATAGGGGYAAGAGGGAA, where X and Y may be either A or G, and subject them to two-dimensional gel electrophoresis. In support of our hypothesis, the inserts exhibited facile transitions into the H form for X = Y = G, or X = Y = A, whereas the transition was much more difficult or impossible for the two non-palindromes (X = A, Y = G or X = G, Y = A). We present evidence that the H form is the structural basis for S1-nuclease hypersensitivity.
361 citations
TL;DR: In this paper, the physics of current-carrying superconductors and normal metals having two or more stable states sustained by Joule self-heating are studied, and the connection between thermal bistability and hysteresis, dropping and stepped currentvoltage characteristics, self-induced oscillations of current and voltage, selfreplication of electrothermal domains and formation of periodic and stochastic resistive structures are considered.
Abstract: This review is devoted to the physics of current-carrying superconductors and normal metals having two or more stable states sustained by Joule self-heating. The creation, propagation, and localization of electrothermal domains and switching waves leading to the transition from one stable state to another in uniform and nonuniform samples are treated in detail. The connection between thermal bistability and hysteresis, dropping and stepped current-voltage characteristics, self-induced oscillations of current and voltage, selfreplication of electrothermal domains, and the formation of periodic and stochastic resistive structures are considered.
316 citations
TL;DR: In this article, the critical properties of exactly soluble Ising model on a planar random dynamical lattice representing a regularization of the zero-dimensional string with internal fermions were investigated.
312 citations
TL;DR: In this paper, a study of an organic polymer ferromagnetic preparation with a transition metal impurity content well below the level likely to significantly affect its magnetic properties is presented. But it is not shown that the impurity can significantly affect the magnetic properties of polymeric polymers.
Abstract: Low-dimensional, especially one-dimensional (1D), organic compounds are known to exhibit the properties of semiconductors, molecular metals and superconductors1. The theoretical prediction of 1D organic ferromagnets and the principles of construction of polymer polyradicals with a ground state spin proportional to a number of monomeric units were proposed in 1977–782,3. For nearly two decades various hydrocarbons of high spin multiplicity have been studied as the model of an organic ferromagnet4–6. Advanced quantum chemistry techniques have been applied for theoretical investigations of the electronic structure of such compounds7–9. Here we present a study of an organic polymer ferromagnetic preparation with a transition metal impurity content well below the level likely to significantly affect its magnetic properties. We find that all the organic polymer ferromagnet samples can be conditionally subdivided into three groups: paramagnetic polymers7–9, spin glasses10 and real polymer ferromagnets.
293 citations
TL;DR: In this paper, a review of the progress in the study of vortex oscillations in rotating superfluids is presented, focusing mainly on the effects of crystalline order in the vortex lattice (the Tkachenko waves especially) and on the boundary problems arising in studies of vortex lines in finite containers.
Abstract: This review covers the progress in the study of vortex oscillations in rotating superfluids. The paper deals with the theory as its principal concern, but the experiments that one can compare with the theory considered are also discussed. Attention is focused mainly on the effects of crystalline order in the vortex lattice (the Tkachenko waves especially) and on the boundary problems arising in studies of vortex oscillations in finite containers. The approach is based mostly on the continuum hydrodynamic theory dealing with dense vortex arrays, and considerable attention is devoted to discussion of this theory in order to understand better the principles upon which the obtained results rest. The theory is traced from the simple description of a rotating classical fluid with continuous vorticity, through that of a perfect fluid with quantized vorticity in the form of an array of vortex lines, then the two-fluid theory of an isotropic superfluid, and finally the theory of rotating anisotropic superfluids such as $^{3}\mathrm{He}$-$A$. Applications of the theory to He II, the superfluid phases of $^{3}\mathrm{He}$, and the superfluid neutron matter in pulsars are discussed.
274 citations
266 citations
TL;DR: In this article, the experimental study of small microwave losses (tan δ ≈ 10−4−10−9) in high-quality dielectric single crystals was devoted to the experimental analysis.
TL;DR: The general thin-wall formalism first elaborated by Israel is developed and applied to the investigation of the motion of various bubbles arising in the course of phase transitions in the very early Universe including new phase bubbles, old phase remnants, and domains.
Abstract: This is a systematic study of the evolution of thin shell bubbles in general relativity. We develop the general thin-wall formalism first elaborated by Israel and apply it to the investigation of the motion of various bubbles arising in the course of phase transitions in the very early Universe including new phase bubbles, old phase remnants, and domains. We consider metric junction conditions and derive constraints both on the decay of metastable states and on the evolution of non- equilibrium scalar field configurations (fluctuations) following from the global geometry of spacetime.
TL;DR: In this paper, the photoelectrochemical behavior of an electrode made of synthetic diamond has been studied for the first time and the photocurrent, differential capacity and dark current vs. potential curves have been measured on semiconductor diamond polycrystalline films on a tungsten substrate in contact with aqueous electrolyte solutions.
TL;DR: In this article, several different mechanisms of generation of isothermal density perturbations, which can be produced along with the adiabatic (inflaton) perturbation during inflation, are discussed.
TL;DR: The phenomenological similarity of the cell and lipid membrane breakdown indicates that pores developed during the electrical breakdown of biological membranes arise in their lipid matrices.
TL;DR: The main result of as mentioned in this paper is that each condition is constructive in the following sense: instead of checking it in all finite volumesv⊂ℤv, it is enough to consider only (a finite amount of) volumes with restricted size.
Abstract: An interactionU is called a completely analytical (CA) interaction, if it satisfies one of 12 given conditions formulated in terms of analyticity properties of the partition functions Zv(u), or correlation decay, or truncated correlation bounds, or asymptotic behavior of ln Zv(u), v→∞. The 12 conditions are presented, together with part of the proof of their equivalence. The main result of the paper is that each condition is constructive in the following sense: instead of checking it in all finite volumesv⊂ℤv, it is enough to consider only (a finite amount of) volumes with restricted size. In particular, the partition functions Z
v
(u+ũ) for the complex perturbationsu+ũ ofu do not vanish for all Vℤ
v
and all Ũ with ∥Ũ∥<ɛ, provided this is true only forv with diam v⩽C(ɛ) and ∥Ũ∥<ɛ′ (but withɛ<ɛ′).
TL;DR: The existence of the 100-kyr cycle and the synchronism between Northern and Southern Hemisphere climates may have their origin in the large glacial-interglacial CO2 changes.
Abstract: Vostok climate and CO2 records suggest that CO2 changes have had an important climatic role during the late Pleistocene in amplifying the relatively weak orbital forcing. The existence of the 100-kyr cycle and the synchronism between Northern and Southern Hemisphere climates may have their origin in the large glacial–interglacial CO2 changes.
TL;DR: Using polymorphic restriction sites to analyse a panel of MHC congeneic and intra-MHC recombinant mouse strains, it is found the TNF genes are located 70 kb proximal to the D gene.
Abstract: Tumour necrosis factor (TNF-alpha) and lymphotoxin (TNF-beta) are related proteins, secreted by macrophages and lymphocytes respectively, which play a role in destruction of tumour cells and virally infected cells (for reviews see refs 1,2). TNF-alpha is a non-glycosylated protein of relative molecular mass 17,000 (Mr 17 K), whereas TNF-beta is a glycoprotein of Mr 25 K. Both TNF-alpha and TNF-beta aggregate into multimers and act through the same receptor molecule on target cells. Genes encoding these two TNF proteins have been cloned from mouse and man and in both are closely linked, being separated by approximately 1 kilobase (kb) of DNA. In the mouse these genes are located on chromosome 17, but in man they are on the short arm of chromosome 6. This segment of chromosome 6 also contains the genes of the major histocompatibility complex (MHC), as does chromosome 17 in the mouse. To find out whether the TNF genes are located within the MHC, we used polymorphic restriction sites to analyse a panel of MHC congeneic and intra-MHC recombinant mouse strains. Initially, we mapped the TNF genes the D or Qa region in the distal half of the mouse MHC. We then studied a gene cluster encompassing part of the D and Qa regions and found the TNF genes are located 70 kb proximal to the D gene.
TL;DR: In this paper, a supersymmetry-breaking mechanism is proposed in low-energy, E/sub 8/ xE/sub 6/, d = 4, gauge theory, which naturally explains the smallness of the supersymmetric-breaking scale compared to the Planck mass.
TL;DR: This paper reviews some recent results based on new techniques used in the analysis of main processor-sharing queueing systems, including the solutions of the problems of determining the sojourn time distributions and the distributions of the number of jobs in the M/G/1/t8 queue under egalitarian and feedback (foreground-background) processor- sharing disciplines.
Abstract: This paper reviews some recent results based on new techniques used in the analysis of main processor-sharing queueing systems. These results include the solutions of the problems of determining the sojourn time distributions and the distributions of the number of jobs in the M/G/1/t8 queue under egalitarian and feedback (foreground-background) processor-sharing disciplines. A brief discussion of some related results is also given.
Book•
01 Jan 1987TL;DR: In this paper, a general outline of the atom-atom potential method and a large number of parameter sets, which cover the most important atomic species encountered in organic compounds, is presented.
Abstract: In this chapter we shall give a general outline of the atom-atom potential method and discuss the ways most frequently used to derive the atom-atom-potential parameters. A large number of parameter sets, which covers the most important atomic species encountered in organic compounds, is presented. In all cases we have indicated the particular compounds and physical properties used in fitting the parameters of a potential. We hope that this material will assist the reader in choosing the set best suited to the particular problem he is interested in.
TL;DR: In this article, the characteristics of the event detected in the Mont Blanc Underground Neutrino Observatory on February 23, 1987, consisting of 5 interactions recorded during 7s are discussed, and it is shown that the event can be explained in terms of detection of neutrinos emitted during the stellar collapse in the Large Magellanic Cloud.
Abstract: We discuss here the characteristics of the event detected in the Mont Blanc Underground Neutrino Observatory on February 23, 1987, consisting of 5 interactions recorded during 7s. The measured energies of the 5 pulses, the duration of the burst, and the advance of the detection time in comparison with the first optical observations give evidence that the event can be explained in terms of detection of neutrinos emitted during the stellar collapse in the Large Magellanic Cloud.
TL;DR: The kinetics of refolding of bovine carbonic anhydrase B was studied by a variety of methods over a wide range of times (from milliseconds to hours) and has been shown that protein refolding proceeds through three stages.
TL;DR: A revision of the structure of the sodium salt, Na-poly(dA), yields only a slightly heteronomous structure with each chain in a B-type conformation, which is in much better agreement with the experimental data underlying the original heteronomous model3.
Abstract: The structure of poly(dA)poly(dT) currently arouses great interest, mainly because dAndTn stretches are associated with considerable DNA bending Until recently the heteronomous DNA described by Arnott et al, with the poly(dA) and poly(dT) chains in A and B conformations respectively, was the only detailed model of this structure Following our earlier studies of the interaction of DNA and monovalent ions, we examined the X-ray diffraction of the bivalent Ca2+ salt of poly(dA)poly(dT) (Ca-poly(dA)poly(dT)) and found no sign of a heteronomous structure: Ca-poly(dA)poly(dT) in fibres shows fully equivalent B-type conformations of the opposite sugar-phosphate chains A revision of the structure of the sodium salt, Na-poly(dA)poly(dT), based on this result, yields only a slightly heteronomous structure with each chain in a B-type conformation, which is in much better agreement with the experimental data underlying the original heteronomous model Both structures, Ca- and Na-poly(dA)poly(dT), have a minor groove narrower than that of the B form: this peculiarity seems to be very important for the interaction of poly(dA)poly(dT) and biologically significant molecules (including proteins and antibiotics) The specific base-pair positions in poly(dA)poly(dT) may account for the DNA bending adjacent to dAndTn tracts
TL;DR: In this article, a multipoint conformal block of Ramond states of the two-dimensional free scalar field is calculated, related to the free energy of the scalar fields on the hyperelliptic Riemann surface under a particular choice of boundary conditions.
TL;DR: In this paper, the local conformational structure and size of a long comb-like macromolecule in dilute solution have been investigated by the scaling method and it is shown that in a wide interval of quality of the solvent the local structure of the chain is characterized by stretching both of the spine and the side branches through the repulsion of their units and the size of the whole chain as a whole turns out to be proportional to N35.
Abstract: The local conformational structure and size of a long comb-like macromolecule in dilute solution have been investigated by the scaling method. It is shown that in a wide interval of quality of the solvent the local structure of the chain is characterized by stretching both of the spine and the side branches through the repulsion of their units and the size of the chain as a whole turns out to be proportional to N35. The repulsion of the units increases the rigidity of the chain on the scale of the order of the dimensions of the side branches. The theoretical relations obtained well agree with the data on the computer experiment for comb-like macromolecules in a θ-solvent.
01 Dec 1987
TL;DR: In this paper, the behavior of the renormalization group is investigated in the neighborhood of the fixed points described by the ''minimal'' conformal theories M/sub p/ with p>>1.
Abstract: The behavior of the renormalization group is investigated in the neighborhood of the fixed points described by the ''minimal'' conformal theories M/sub p/ with p>>1. In the leading approximation in 1/p a field theory is constructed which corresponds to the renormalization-group trajectory connecting the fixed points M/sub p/ and M/sub p//sub -1/.
TL;DR: A model is suggested for ion binding to PtdCho membranes, according to which the ion-binding sites are considered as point defects in the structure of lipid head-groups arranged over a trigonal lattice.
Abstract: The dependence of electrophoretic mobility of multilamellar liposomes composed of egg phosphatidylcholine (PtdCho), dimyristoyl-glycerophosphocholine (Myr2Gro-P-Cho) and dipalmitoyl-glycerophosphocholine (Pam2-Gro-P-Cho) on the concentration of several cations and anions has been measured. Values of surface densities of binding sites and intrinsic binding constants of ions to liposome membranes were determined by processing the results in the framework of Gouy-Stern theory. Sharp reductions in the positive surface potential of Myr2Gro-P-Cho and Pam2Gro-P-Cho liposomes have been detected at the thermotropic transition of the lipids from the gel to liquid-crystalline phase. Similar alterations of liposome surface potential were revealed at the temperature of pretransition, as well as at about 50°C, in the case of Pam2Gro-P-Cho. A model is suggested for ion binding to PtdCho membranes, according to which the ion-binding sites are considered as point defects (vacancies) in the structure of lipid head-groups arranged over a trigonal lattice.