Spectral and electroluminescent properties of coordination compounds of terbium (III) with ibuprofen (in solid form, chloroform solutions, and polyvinylcarbazole films)

Spectral properties of terbium (III) complexes with composition of TbL3DL, where L is an anion of d,l-2-(4-isobutylphenyl)propanoic acid (ibuprofen) and DL is 2,2′-dipyridyl (Dipy), 1,10-phenanthroline (Phen), or triphenylphosphine oxide (TPPO), have been studied in a solid form, chloroform solutions, and polyvinylcarbazole (PVC) films. It has been demonstrated that, in PVC films, occupation of the emitting level of terbium (III) involves the participation of polymer. The emission decay lifetimes of terbium in the chloroform solutions and PVC films have been measured. The possibility of the appearance of electroluminescence of complexes in PVC films has been studied

The guard lymph nodes when choosing tactics of operational treatment of colorectal cancer

In this article, we analyzed the studies, that were conducted over the past 10 years to study the role of the "guard lymph node" in colorectal cancer. Researches were studied prospectively as well as retrospectively, in which "guard lymph nodes" were defined and was studied the lesion of lymph nodes 1, 2 and 3 orders. The purpose of this work is to evaluate and compare the results of operations used in collorectal cancer. Results and conclusions are presented on the basis of developed and developing countries

Formation of a "Cluster Molecule" (C20)2 and its thermal stability

The possible formation of a "cluster molecule" (C20)2 from two single C20 fullerenes is studied by the tight-binding method. Several (C20)2 isomers in which C20 fullerenes are bound by strong covalent forces and retain their identity are found; actually, these C20 fullerenes play the role of "atoms" in the "cluster molecule". The so-called open-[2+2] isomer has a minimum energy. Its formation path and thermal stability at T = 2000 - 4000 K are analyzed in detail. This isomer loses its molecular structure due to either the decay of one of C20 fullerenes or the coalescence of two C20 fullerenes into a C40 cluster. The energy barriers for the metastable open-[2+2] configuration are calculated to be U = 2 - 5 eV.Comment: 21 pages, 8 figure

Bioinformatics advances in saliva diagnostics

There is a need recognized by the National Institute of Dental & Craniofacial Research and the National Cancer Institute to advance basic, translational and clinical saliva research. The goal of the Salivaomics Knowledge Base (SKB) is to create a data management system and web resource constructed to support human salivaomics research. To maximize the utility of the SKB for retrieval, integration and analysis of data, we have developed the Saliva Ontology and SDxMart. This article reviews the informatics advances in saliva diagnostics made possible by the Saliva Ontology and SDxMart

Decay and fusion as two different mechanisms of stability loss for the (C_20)_2 cluster dimer

The thermal stability of the (C_20)_2 cluster dimer consisting of two C_20 fullerenes is examined using a tight-binding approach. Molecular dynamics simulations of the (C_20)_2 dimer at temperatures T = 2000 - 3500 K show that the finite lifetime \tau of this metastable system is determined by two fundamentally different processes, the decay of one of the C_20 fullerenes and the fusion of two C_20 fullerenes into the C_40 cluster. The activation energies for these processes Ea = 3.4 and 2.7 eV, respectively, as well as their frequency factors, have been determined by analyzing the dependence of \tau on T.Comment: Slightly modified version of the paper to appear in JETP Let

Anomalous Thermal Stability of Metastable C_20 Fullerene

The results of computer simulation of the dynamics of fullerene C_20 at different temperatures are presented. It is shown that, although it is metastable, this isomer is very stable with respect to the transition to a lower energy configuration and retains its chemical structure under heating to very high temperatures, T ~ 3000 K. Its decay activation energy is found to be E_a ~ 7 eV. Possible decay channels are studied, and the height of the minimum potential barrier to decay is determined to be U = 5.0 eV. The results obtained make it possible to understand the reasons for the anomalous stability of fullerene C_20 under normal conditions.Comment: Slightly corrected version of the paper submitted to Phys. Solid Stat

Ecological characteristics of mollusks in the Utlyukskij Liman

Phylum Mollusca is represented in the Utlyukskij liman by 63 species, of which 43 belong to class Gastropoda and 20 species to class Bivalvia. Main groups of mollusks within the Utlyukskij Liman are irregularly distributed, and each part has a some slightly peculiarities. Data obtained show a weak correlation between the composition of mollusk communities and the type of the bottom. It was noted the presence of sufficiently stable "core" of malacofauna of entire estuary; while the composition of mollusk communities in certain areas reflects the specifics of the local hydrological conditions. Both quantitative and qualitative characters of mollusk communities are extremely inconstant in the the Utlyukskij Liman within the same area and even within the same sampling station. The structure and the proportion of mollusk groups is changing in a very short time. Key words: Mollusca; fauna; distribution; ecology; Utlyukskij Liman; the Sea of Azov

Metastable quasi-one-dimensional ensembles of nitrogen clusters N_8

By means of ab initio and tight-binding calculations it is shown that metastable nitrogen clusters N_8 (boats) can form quasi-one-dimensional ensembles in which the nearest clusters N_8 are bound to each other by covalent bonds. Those ensembles are characterized by rather high energy barriers (~ 0.3 eV) that prevent the fission of the ensembles into isolated N_8 clusters and/or N_2 molecules.Comment: 3 pages, 4 ps figure

Search for Θ+(1540)\Theta^+(1540) pentaquark in high statistics measurement of γp→Kˉ0K+n\gamma p \to \bar K^0 K^+ n at CLAS

The exclusive reaction $\gamma p \to \bar K^0 K^+ n$ was studied in the photon energy range between 1.6-3.8 GeV searching for evidence of the exotic baryon $\Theta^+(1540)\to nK^+$. The decay to $nK^+$ requires the assignment of strangeness $S=+1$ to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 $pb^{-1}$. No evidence for the $\Theta^+$ pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and $nK^+$ mass. The 95% CL upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb.Comment: Submitted to Physical Review Letter