An explicitly correlated Mukherjee's state specific coupled cluster method: development and pilot applications

This paper reports development of the explicitly correlated variant of Mukherjee's state specific multireference coupled cluster method (MkCC-F12). The current implementation is restricted to conventional single and double excitations and to pseudo-double excitations related to the Slater Type Geminal (STG) correlation factor using the SP ansatz. The performance of the MkCCSD-F12 was tested on calculations of singlet methylene, dissociation curve of the fluorine molecule, and the BeH(2) insertion pathway. As expected, the results of the newly developed method reconfirm the significantly faster convergence with respect to the basis set limit compared to the traditional expansion in Slater determinants. Results prove that treating the correlation factor separately for each reference is appropriate.     

On uniqueness for a semilinear parabolic system coupled in an equation and a boundary condition

We consider the system

     

Conformationally tailored N-[(2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl)carbonyl]proline templates as molecular tools for the design of peptidomimetics. Design and synthesis of fibrinogen receptor antagonists

The proline peptide bond was shown by 2D proton NMR studies to exist exclusively in the trans conformation in benzyl (2S)-1-[[(2S)-2-methyl-6-nitro-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl]carbonyl]-2-pyrrolidinecarboxylate [(S,S)-11], benzyl (2S)-1-[[(2S)-2-methyl-7-nitro-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl]carbonyl]-2-pyrrolidinecarboxylate [(S,S)-9], and in the corresponding 6-amino and 7-amino carboxylic acids (S,S)-3 and (S,S)-4. On the other hand, the diastereomers (R,S)-11 and (R,S)-9 containing an (R)[2-methyl-6/7-nitro-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl]carbonyl moiety, and the diastereoisomers (R,S)-3 and (R,S)-4 incorporating an (R)[6/7-amino-2-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazin-2-yl]carbonyl moiety were found to exist as equilibria of trans(63-83%) and cis(17-37%) isomers. These conformationally defined templates were applied in the construction of RGD mimetics possessing antagonistic activity at the platelet fibrinogen receptor.     

Ternary MIn2S4 (M = Mn,Fe, Co,Ni) Thiospinels – Crystal Structure and Thermoelectric Properties

A combined structural, magnetic and thermoelectric study of polycrystalline ternary MIn₂S₄ (M = Mn, Fe, Co, Ni) thiospinels is presented. All compounds crystallize with MgAl₂O₄-type structure. Rietveld refinement analysis confirmed that the preferred crystallographic position of transition metal element changes from mainly tetrahedral 8a for Mn to exclusively octahedral 16d for Ni (i.e. increase of the inversion parameter). Magnetic susceptibility measurements revealed M-elements to possess 2+ oxidation state in MIn₂S₄. All these compounds order antiferromagnetically with Néel temperatures T_N ranging from 5–13 K. The studied thiospinels are n-type semiconductors with large values of electrical resistivity ρ > 0.6 Ω · m at room temperature. An increase of the inversion parameter leads to a reduction of the determined activation energies, as well as to a more disorder-like behavior of thermal conductivity. The highest thermoelectric Figure of merit ZT was observed for MIn₂S₄ with M = Fe, Ni, which adopt inverse spinel structure.     

On the resolution of time problem in quantum gravity induced from unconstrained membranes

The relativistic theory of unconstrained p-dimensional membranes (p-branes) is further developed and then applied to the embedding model of induced gravity. Space-time is considered as a 4-dimensional unconstrained membrane evolving in an N-dimensional embedding space. The parameter of evolution or the evolution time is a distinct concept from the coordinate time t=x⁰. Quantization of the theory is also discussed. A covariant functional Schrödinger equation has a solution for the wave functional such that it is sharply localized in a certain subspace P of space-time, and much less sharply localized (though still localized) outside P. With the passage of evolution the region P moves forward in space-time. Such a solution we interpret as incorporating two seemingly contradictory observations: (i) experiments clearly indicate that space-time is a continuum in which events are existing; (ii) not the whole 4-dimensional space-time, but only a 3-dimensional section which moves forward in time, is accessible to our immediate experience. The notorious problem of time is thus resolved in our approach to quantum gravity. Finally we include sources into our unconstrained embedding model.     

On a certain identity satisfied by a derivation and an arbitrary additive mapping II

Summary The structure of prime ringsR and nonzero derivationsd onR, satisfyingd(x)f(x) = 0 for allx R, is described,f being a nonzero additive mapping ofR. Supported in part by a grant from the Ministry of Science of Slovenia.     

Synthese der Clathratverbindungen des Typs Cd(en)Pd(CN)4·2G

In this paper three compounds with the same host molecule of Cd(en)Pd(CN)₄ type, but of different organic components such as thiophene, pyrrole and furan were described.     

Enhancing sensitivity of liquid chromatographic/ion-trap tandem mass spectrometric determination of estrogens by on-line pre-column derivatization

A rapid and sensitive liquid chromatographic/ion-trap mass spectrometric method has been developed for the simultaneous determination of estriol, alpha-, beta-estradiol, 17alpha-ethynylestradiol and estrone. The substances were extracted from river water samples (typically 250 ml) and cleaned-up using two-stage solid-phase extraction (SPE). 12-(Difluoro-1,3,5-triazinyl)-benz[f]isoindolo-[1,2b][1,3]benzothiazolidine was applied as a derivatizing agent. The recovery for each compounds ranged from 75 to 88% and the repeatability represented as RSDs ranged from 5.6 to 8.4%. Limits of detection (LOD, 3 x S/N) were 67-285 pg/l.