Insight into the binary mixture of ethyl lactate+acetonitrile from density,speed of sound and refractive index measurements

Density, sound velocity and refractive index of ethyl lactate + acetonitrile mixtures were measured at five temperatures from 283.15 to 323.15 K. Excess molar volumes, partial molar volumes, thermal expansion coefficients, isentropic compressibility and molar refraction values were calculated. It is concluded that deviations from ideality in this system should be assigned to the ability of the smaller acetonitrile molecules to occupy free volume space of ethyl lactate.     

Greybody factors and quasinormal modes for a nonminimally coupled scalar field in a cloud of strings in (2 + 1)-dimensional background

We study the propagation of a probe massless nonminimally coupled scalar field in a fixed gravitational background of a cloud of strings in (2 + 1) dimensions. We obtain exact analytical expressions for the reflection coefficient, the absorption cross section, the decay rate as well as the quasinormal frequencies. The impact of the nonminimal coupling is investigated in detail. Our results show that universality is not respected in general, and that scalar perturbations are stable.     

Phase Space View of Ensembles of Excited States

The density functional theory and its extension to ensembles of excited states can be formalized as thermodynamics. However, these theories are not unique because one of their key quantities, the kinetic energy density,can be defined in several ways. Usually, the everywhere positive gradient form is applied; however, other forms are also acceptable, provided they integrate to the true kinetic energy. Recently, a kinetic energy density of the ground-state theory maximizing the information entropy has been proposed. Here, ensemble kinetic energy density, leading to extremum information entropy, is derived via constrained search. The corresponding ensemble temperature is found to be constant.     

Contractions, Deformations and Curvature

The role of curvature in relation with Lie algebra contractions of the pseudo-orthogonal algebras so(p,q) is fully described by considering some associated symmetrical homogeneous spaces of constant curvature within a Cayley–Klein framework. We show that a given Lie algebra contraction can be interpreted geometrically as the zero-curvature limit of some underlying homogeneous space with constant curvature. In particular, we study in detail the contraction process for the three classical Riemannian spaces (spherical, Euclidean, hyperbolic), three non-relativistic (Newtonian) spacetimes and three relativistic ((anti-)de Sitter and Minkowskian) spacetimes. Next, from a different perspective, we make use of quantum deformations of Lie algebras in order to construct a family of spaces of non-constant curvature that can be interpreted as deformations of the above nine spaces. In this framework, the quantum deformation parameter is identified as the parameter that controls the curvature of such “quantum” spaces.     

The effects of isatin (indole-2, 3-dione) on pituitary adenylate cyclase-activating polypeptide-induced hyperthermia in rats

Background  

Previous studies have demonstrated that centrally administered natriuretic peptides and pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) have hyperthermic properties. Isatin (indole-2, 3-dione) is an endogenous indole that has previously been found to inhibit hyperthermic effects of natriuretic peptides. In this study the aim was to investigate the effects of isatin on thermoregulatory actions of PACAP-38, in rats.     

Convenient synthesis of fused heterocycles from α-ketohydroximoyl chlorides and heterocyclic amines

Nitroso derivatives of imidazo[1,2-a]pyridine ( 11, 13, 14 ), imidazo[1,2-a]pyrimidine ( 15 ), imidazo[1,2-a]pyrazine ( 16 ), imidazo[1,2-b]pyrazole ( 17 ), and imidazo[1,2-b]-1,2,4-triazole ( 19 ) were obtained in good yields from α-ketohydroximoyl chlorides 3 and 2-aminopyridines ( 4–6 ), 2-aminopyrimidine ( 7 ), 2-aminopyrazine ( 8 ), 5-amino-3-phenylpyrazole ( 9 ), and 3-amino-2H-1,2,4-triazole ( 10 ), respectively. Under different conditions, the reaction of 3 with 3-amino-2H-1,2,4-triazole ( 10 ) and 2-aminopyrazine ( 8 ) afforded the noncyclized substitution products 18 and 22 , respectively. The structures of the products were assigned and confirmed on the basis of their elemental analyses, spectral data, and alternate synthesis wherever possible.     

On the decay of the Higgs particle into two lepton pairs

The decay of the standard Higgs into two lepton pairs is found to have a very small branching ratio, contrary to a recent result in the literature. The physical reasons for this discrepancy are discussed.