Doubly hybrid density functional for accurate descriptions of nonbond interactions, thermochemistry, and thermochemical kinetics

We develop and validate a density functional, XYG3, based on the adiabatic connection formalism and the Görling–Levy coupling-constant perturbation expansion to the second order (PT2). XYG3 is a doubly hybrid functional, containing 3 mixing parameters. It has a nonlocal orbital-dependent component in the exchange term (exact exchange) plus information about the unoccupied Kohn–Sham orbitals in the correlation part (PT2 double excitation). XYG3 is remarkably accurate for thermochemistry, reaction barrier heights, and nonbond interactions of main group molecules. In addition, the accuracy remains nearly constant with system size

The O(N) Model at Finite Temperature: Renormalization of the Gap Equations in Hartree and Large-N Approximation

The temperature dependence of the sigma meson and pion masses is studied in the framework of the O(N) model. The Cornwall-Jackiw-Tomboulis formalism is applied to derive gap equations for the masses in the Hartree and large-N approximations. Renormalization of the gap equations is carried out within the cut-off and counter-term renormalization schemes. A consistent renormalization of the gap equations within the cut-off scheme is found to be possible only in the large-N approximation and for a finite value of the cut-off. On the other hand, the counter-term scheme allows for a consistent renormalization of both the large-N and Hartree approximations. In these approximations, the meson masses at a given nonzero temperature depend in general on the choice of the cut-off or renormalization scale. As an application, we also discuss the in-medium on-shell decay widths for sigma mesons and pions at rest.Comment: 21 pages, 6 figures, typos corrected and refs. added, accepted in Journal of Physics

ν−K0\nu - K^0 Analogy, Dirac-Majorana Neutrino Duality and the Neutrino Oscillations

The intent of this paper is to convey a new primary physical idea of a Dirac-Majorana neutrino duality in relation to the topical problem of neutrino oscillations. In view of the new atmospheric, solar and the LSND neutrino oscillation data, the Pontecorvo $\nu - K^0$ oscillation analogy is generalized to the notion of neutrino duality with substantially different physical meaning ascribed to the long-baseline and the short-baseline neutrino oscillations. At the level of CP-invariance, the suggestion of dual neutrino properties defines the symmetric two-mixing-angle form of the widely discussed four-neutrino $(2+2)$-mixing scheme, as a result of the lepton charge conservation selection rule and a minimum of two Dirac neutrino fields. With neutrino duality, the two-doublet structure of the Majorana neutrino mass spectrum is a vestige of the two-Dirac-neutrino origin. The fine neutrino mass doublet structure is natural because it is produced by a lepton charge symmetry violating perturbation on a zero-approximation system of two twofold mass-degenerate Dirac neutrino-antineutrino pairs. A set of inferences related to the neutrino oscillation phenomenology in vacuum is considered.Comment: 13 pages, LaTeX. Minor modifications, new references adde

Potentiometric Determination of Dopamine Using a Solid-Contact Polymeric Membrane Ion-Selective Electrode

A simple solid-contact polymeric membrane ion-selective electrode for determination of dopamine was developed. The electrode is fabricated with polymeric membranes incorporating heptakis(2,3,6-tri-o-methyl)-beta-cyclodextrin as ionophore and sodium trakis[3,5-bis(trifluoromethyl)phenyl]borate as ionic additive. Using hydrophobic poly(3-octylthiophene) as solid-contact transducer, the sensor displays a stable potential response for detection of dopamine in 2 mM HAc-NaAc buffer solution (pH 4.4) within a wide concentration range of 3.0 x 10(-5) M-1.0 x 10(-3) M with a sub-Nernstian slope of 43.8 +/- 0.5 mV/dec. The detection limit calculated as the intersection of the two slope lines is 1.3 x 10(-5) M. The electrode exhibits good selectivity over inorganic ions, pharmaceutical excipients and ascorbic acid. In addition, the electrode shows a stable potential response over a wide pH range of 4.0 to 8.5, fast response time (less than 10 s) and excellent repeatability. The proposed electrode has been successfully applied for direct potentiometric determination of dopamine in pharmaceutical formulation without pretreatment procedures

Separation of a single photon and products of the π0,η,Ks0\pi^0,\eta, K^0_s meson neutral decay channels in the CMS electromagnetic calorimeter using neural network

The artificial neural network approach is used for separation of signals from a single photon $\gamma$ and products of the $\pi^0,\eta, K^0_s$ meson neutral decay channels on the basis of the data from the CMS electromagnetic calorimeter alone. Rejection values for the three types of mesons as a function of single photon selection efficiencies are obtained for two Barrel and one Endcap pseudorapidity regions and initial \Et of 20, 40, 60 and 100 GeV.Comment: 16 pages, uses cernrep.cls style fil

Proteomic responses reveal the differential effects induced by cadmium in mussels Mytilus galloprovincialis at early life stages

Cadmium (Cd) has become an important metal contaminant and posed severe risk on the organisms in the coastal environments of the Bohai Sea. Marine mussel Mytilus galloprovincialis is widely distributed along the Bohai coast and consumed as seafood by local residents. Evidences indicate that the early stages of marine organisms are more sensitive to metal contaminants. In this study, we applied two-dimensional electrophoresis-based proteomics to characterize the biological effects of Cd (50 mu g L-1) in the early life stages (D-shape larval and juvenile) of mussels. The different proteomic responses demonstrated the differential responsive mechanisms to Cd exposure in these two early life stages of mussels. In details, results indicated that Cd mainly induced immune and oxidative stresses in both D-shape larval and juvenile mussels via different pathways. In addition, the significant up-regulation of triosephosphate isomerase and metallothionein confirmed the enhanced energy demand and mobilized detoxification mechanism in D-shape larval mussels exposed to Cd. In juvenile mussels, Cd exposure also induced clear apoptosis. Overall, this work suggests that Cd is a potential immune toxicant to mussel M. galloprovincialis at early life stages. (C) 2016 Elsevier Ltd. All rights reserved

An integrated proteomic and metabolomic study on the gender-specific responses of mussels Mytilus galloprovincialis to tetrabromobisphenol A (TBBPA)

Tetrabromobisphenol A (TBBPA), accounting for the largest production of brominated flame-retardants (BFRs) along the Laizhou Bay in China, is of great concern due to its diverse toxicities. In this study, we focused on the gender-specific responses of TBBPA in mussel Mytilus galloprovincialis using an integrated proteomic and metabolomic approach. After exposure of TBBPA (10 mu g L-1) for one month, a total of 9 metabolites and 67 proteins were altered in mussel gills from exposed group. The significant changes of metabolites in female mussel gills from exposed group exhibited the disturbances in energy metabolism and osmotic regulation, while in male samples only be found the variation of metabolites related to osmotic regulation. iTRAQ-based proteomic analysis showed biological differences between male and female mussel gills from solvent control group. The higher levels of proteins related to primary and energy metabolism and defense mechanisms in male mussel gills meant a greater anti-stress capability of male mussels. Further analysis revealed that TBBPA exposure affected multiple biological processes consisting of production and development, material and energy metabolism, signal transduction, gene expression, defense mechanisms and apoptosis in both male and female mussels with different mechanisms. Specially, the responsive proteins of TBBPA in male mussels signified higher tolerance limits than those in female individuals, which was consistent with the biological differences between male and female mussel gills from solvent control group. This work suggested that the gender differences should be considered in ecotoxicology. (C) 2015 Elsevier Ltd. All rights reserved

Tracing Noble Gas Radionuclides in the Environment

Trace analysis of radionuclides is an essential and versatile tool in modern science and technology. Due to their ideal geophysical and geochemical properties, long-lived noble gas radionuclides, in particular, 39Ar (t1/2 = 269 yr), 81Kr (t1/2 = 2.3x10^5 yr) and 85Kr (t1/2 = 10.8 yr), have long been recognized to have a wide range of important applications in Earth sciences. In recent years, significant progress has been made in the development of practical analytical methods, and has led to applications of these isotopes in the hydrosphere (tracing the flow of groundwater and ocean water). In this article, we introduce the applications of these isotopes and review three leading analytical methods: Low-Level Counting (LLC), Accelerator Mass Spectrometry (AMS) and Atom Trap Trace Analysis (ATTA)

Per- and poly-fluoroalkyl substances (PFASs) in the urban, industrial, and background atmosphere of Northeastern China coast around the Bohai Sea: Occurrence, partitioning, and seasonal variation

Air samples were collected using high-volume samplers at two coastal towns on the Bohai Sea in China, 320 km apart, and at a background site (North Huangcheng Island) in the Bohai Sea, 50 km from the coast. A suite of neutral and ionic per- and poly-fluoroalkyl substances (PFASs) was investigated. Urban activity was related to high levels of neutral PFASs at Tianjin while perfluorooctanoic carboxylic acid (PFOA) was dominant in the atmosphere at Weifang, possibly due to industrial sources. Polyfluoroalkyl phosphoric acid diesters (diPAPs) occurred in the particle phase only, with a total concentration range of 0.02-6.72 pg m(-3). The dominant homologue was 6:2 diPAP. PFASs profiles at NHI suggested direct atmospheric transport of neutral and ionic PFASs from source regions. Temperature-dependent partitioning of fluorotelomer alcohols (FTOHS) was observed in winter, when total concentrations and particle-phase fractions of FTOHs were significantly higher as compared to those in summer. Correlation analyses suggested more active gas-phase degradation of FTOHs in summer and likely heterogeneous degradation in both seasons. Overall, it is necessary to account for ionic PFASs in both gas and particle phases and particulate matter was important for atmospheric transport and for determining the fate of PFASs, especially in areas close to a source region. (C) 2017 Elsevier Ltd. All rights reserved.</p