Electron density of states at the edge of the valence band of Cd0.88Fe0.12Se—A photoemission yield study

The electronic structures of Cd_0.88Fe_0.12Se and CdSe have been investigated by photoemission yield spectroscopy (PYS) in the photon energy range from 5 to 12 eV. The () surfaces were obtained by cleavage under ultrahigh vacuum (UHV) conditions. An Fe-related emission appeared at 0.58 eV above the valence band edge. The freshly cleaved surface of Cd_0.88Fe_0.12Se interacted with ambient atmosphere more strongly than CdSe crystal. Leaving the sample in an UHV chamber at room temperature enabled us to identify surface related features and to observe decrease of the ionization energy E_i, energy threshold E_d and the crystal affinity χ due to change of the surface conditions. Effective density of states, derived from the experimental spectra of Cd_0.88Fe_0.12Se exhibits, in contrast with CdSe, a surface-related feature degenerated with the bulk valence band.     

Parkintin: a new flavanone with epoxy-isopentyl moiety from Parkinsonia aculeata Linn. (Caesalpiniaceae)

A new flavanone with epoxy-isopentyl moiety named parkintin has been isolated from the methanol soluble part of Parkinsonia aculeata Linn. belonging to the family Caesalpiniaceae. The structure of parkintin has been established with the aid of spectroscopic techniques including COSY and HMBC experiments.     

Color versus bioactivity in the flowers of Bougainvillea spectabilis (Nyctaginaceae)

The methanolic extracts of Bougainvillea spectabilis (Nyctaginaceae) flowers (five different colors) were screened biologically by performing four bioassays: antibacterial, antifungal, brine shrimp lethality and phytotoxicity. It was observed that the methanolic extract of white flowers was the most biologically active among all tested extracts. The extracts of white, orange and shocking pink flowers inhibit, while the extracts of red and violet flowers promote, the growth of Lemna plants. The extract of white flowers also exhibits toxicity against shrimp larvae with a LD50 value of 33.5627 microg/mL. However, none of the tested samples gave positive responses against any tested fungi.     

Measurements of the mass, total width, and two-photon partial width of the eta(c) meson

Using 13.4 fb(-1) of data collected with the CLEO detector at the Cornell Electron Storage Ring, we have observed 300 events for the two-photon production of ground-state pseudoscalar charmonium in the decay eta(c)-->K(0)(S)K-/+pi(+/-). We have measured the eta(c) mass to be [2980.4+/-2.3 (stat)+/-0.6 (syst)] MeV and its full width as [27.0+/-5.8 (stat)+/-1.4 (syst)] MeV. We have determined the two-photon partial width of the eta(c) meson to be [7.6+/-0.8 (stat)+/-0.4 (syst)+/-2.3 (br)] keV, with the last uncertainty associated with the decay branching fraction.     

Production and decay of F+(2030) observed in νμ interactions in emulsion

An event representing the production and decay of the charmed F⁺ meson has been identified by means of a 3-constraint fit to decay hypothesis F⁺ → π⁺π⁺π^?π⁰, in which both γ-rays from the π⁰ converted. The event was produced by a charged current ν_μ interaction in an emulsion stack located inside the Fermilab 15-foot bubble chamber. The F⁺ traveled 50 μm, corresponding to a proper time of 1.4 × 10^?13 seconds, before decaying in flight. Its mass was determined to be 2017 ± 25MeV.     

Search for B --> tau(nu) and B --> K(nu)nu

We report results of a search for B-->tau(nu) in a sample of 9.7 x 10(6) charged B meson decays. We exclusively reconstruct the companion B decay to suppress background. We set an upper limit on the branching fraction B(B-->tau(nu))<8.4 x 10(-4) at 90% confidence level. We also establish B(B+/--->K+/-nu(nu))<2.4 x 10(-4) at 90% confidence level.     

New dimeric Schiff base quinoline complexes: Synthesis,spectral characterization,electrochemistry and cytotoxicity

A novel Schiff base ligand (H‐DPPMHQ) derived from 2‐hydrazineylquinoline and 1,3‐diphenyl‐1H‐pyrazole‐5‐carbaldehyde and its dimeric complexes with compositions [Cr(DPPMHQ)Cl]₂?2Cl and [M(DPPMHQ)Cl]₂ (where M = Cu(II), Co(II), Ni(II) and Zn(II)) have been synthesized and characterized using physicochemical methods like elemental analysis, magnetic susceptibility and molar conductivity measurements, multispectral techniques and electrochemical studies. The molar conductance data reveal that all metal chelates are non‐electrolytes, except the Cr(III) complex which shows a Λ_M value of 146.82 Ω^?1 cm² mol^?1, indicating that it is a 1:2 electrolyte. Infrared spectral results show that the metal is organized through four nitrogen atoms (azomethine and deprotonated imine groups, pyrazole and quinoline rings) besides chlorine atoms. The NH proton is also displaced during complexation, as indicated by ¹H NMR spectral data. Based on the electron spin resonance and ligand field parameter data, the bonding parameters of these complexes have been calculated. Using Coats–Redfern and Horowitz–Metzger equations, thermodynamic parameters were determined. The spectral data indicate that the dimeric complexes have octahedral geometry around the central metal ions. The cytotoxic activities of all compounds were evaluated towards human breast cancer (MCF‐7) and lung cancer (A549) cell lines.     

A normoxic acrylic acid polymer gel for dosimetery in radiation therapy

Journal of Radioanalytical and Nuclear Chemistry - A novel low toxic normoxic polymer gel dosimeter containing acrylic acid monomer is prepared and characterized for dosimetry in radiotherapy. Gel...