Strong spin-two interaction and general relativity

The concept of short range strong spin-two (f) field (mediated by massive f-mesons) and interacting directly with hadrons was introduced along with the infinite range (g) field in early seventies. In the present review of this growing area (often referred to as strong gravity) we give a general relativistic treatment in terms of Einstein-type (non-abelian gauge) field equations with a coupling constant Gf reverse similar, equals 1038 GN (GN being the Newtonian constant) and a cosmological term λf ƒ;μν (ƒ;μν is strong gravity metric and λf not, vert, similar 1028 cm− is related to the f-meson mass). The solutions of field equations linearized over de Sitter (uniformly curves) background are capable of having connections with internal symmetries of hadrons and yielding mass formulae of SU(3) or SU(6) type. The hadrons emerge as de Sitter “microuniverses” intensely curved within (radius of curvature not, vert, similar10−14 cm).The study of spinor fields in the context of strong gravity has led to Heisenberg's non-linear spinor equation with a fundamental length not, vert, similar2 × 10−14 cm. Furthermore, one finds repulsive spin-spin interaction when two identical spin-Image particles are in parallel configuration and a connection between weak interaction and strong gravity.Various other consequences of strong gravity embrace black hole (solitonic) solutions representing hadronic bags with possible quark confinement, Regge-like relations between spins and masses, connection with monopoles and dyons, quantum geons and friedmons, hadronic temperature, prevention of gravitational singularities, providing a physical basis for Dirac's two metric and large numbers hypothesis and projected unification with other basic interactions through extended supergravity.

Miscibility of poly(phenyl acrylate) with acrylonitrile/styrene copolymers

The Blase transition and phase behavior of blends of poly(pheny1 acrylate) with poly(acrylonitri1eco-styrene) was studied by differential scanning calorimetry. It was found that poly(pheny1 acrylate) is miscible with poly(acrylonitri1e-co-styrenes) within a specific range of copolymer composition. The segmental interaction parameters were estimated and found to be positive for all three pairs. The miscibility in thissystem appears to be the consequence of the intramolecular repulsion between styrene and acrylonitrile units.

Kinetic studies on the interaction of gold(III) with nucleic acids. I. Native DNA-Au(III) system-spectrophotometric studies

Kinetics of the interaction of Au(III) with native calf thymus DNA has been studied spectrophotometrically to determine the kinetic parameters and to examine their dependency on the concentrations of DNA and Au(III), temperature, ionic strength and pH. The reaction is of the first order with respect to both the nucleotide unit of DNA and Au(III) in the stoichiometry of 2∶1 respectively. The rate constants vary with the initial ratio of DNA to Au(III) and is attributed to the effect of free chloride ions and the existence of a number of reaction sites with slight difference in the rate constants. The activation energies of this interaction have been found to be 14–16 kcal/mol. From the effect of ionic strength the reaction is found to occur between a positive and a negative ion in the rate-limiting step. The logarithm of rate constants are the linear function of pH and the slopes are dependent on ther-values. A plausible mechanism has been proposed which involves a primary dissociation of the major existing species (AuCl2(OH)2)−, to give (AuCl2)+ which then reacts with a site in the nucleotide unit of DNA in the rate-liminting step followed by a rapid binding to another site on the complementary strand of the DNA double helix. There exist a number of binding sites with slight difference in reactivity.

Interaction of rhodium(III) with DNA

The nature of interaction of Rh(III) with DNA was studied using viscometry and ultraviolet, visible and infrared spectroscopy. The rate of interaction was found to be very slow at room temperature taking several days for completion. The time needed to attain equilibrium is dependent on the concentrations of metal ion, higher the concentration shorter the period required for equilibration. Visible spectra of Rh(III) were found to alter considerably in the presence of DNA. An increase in absorbance and a red shift were observed in the ultraviolet spectra of DNA in the presence of Rh(III). The specific viscosity of DNA solution was found to decrease asymptotically with time and concentrations of metal ion. The melting temperature of DNA was found to increase at lower metal ion concentrations, whereas at higher values a decrease was obtained. At still higher metal ion concentrations (Image ) a ‘nonmeltable state’ of DNA was observed. These results seem to indicate that Rh(III) binds both with the phosphate and the bases of the DNA.

A comparative study of the interaction of nickel clusters with buckminsterfullerene, C60, and graphite

Interaction of nickel deposited on multilayer films of C60 has been investigated in comparison with that on amorphized graphite by employing photoemission spectroscopy. It is shown that unlike with graphite, Ni interacts strongly with C60 causing large changes in C(1s) and C(2p) binding energies. The increase in the Ni(2p) binding energy at small Ni coverages is also far greater on c60 than on graphite.

Stereochemical studies on cyclic peptides. Part XI. Conformation of cyclic pentapeptides having intramolecular 3 leads to 1 hydrogen bonds.

Conformational analysis of cyclic pentapeptides having two intra-ring 3 leads to 1 hydrogen bonds has been carried out. It is found that the structure can easily be formed with trans planar peptide units without causing significant angular strain at the alpha-carbon atoms. Four different types of conformations designated Types I--IV are possible for the backbone structure. Details of these four types of conformations and also the accommodating possibility of these types for allglycyl and all-alanyl residues are presented. Three of the four types have relatively low energies for glycyl residues whereas the other one has a slightly higher energy. When alanyl residues are introduced at the five alpha-carbon atoms, the types that are energetically favourable depend upon the sequence of isomers. Energy calculations have also been carried out for the combinations of glycyl, L- and D-alanyl residues. The theoretical results are compared with available experimental observations both from solution and solid state studies.