Beta decay of 101Sn

The β decay of the very neutron-deficient isotope ¹⁰¹Sn was studied at the GSI on-line mass separator using silicon detectors for recording charged particles and germanium detectors for γ-ray spectroscopy. Based on the β-delayed proton data the production cross-section of ¹⁰¹Sn in the ⁵⁰Cr + ⁵⁸Ni fusion-evaporation reaction was determined to be about 60nb. The half-life of ¹⁰¹Sn was measured to be 1.9(3)s. For the first time β-delayed γ-rays of ¹⁰¹Sn were tentatively identified, yielding weak evidence for a cascade of 352 and 1065keV transitions in ¹⁰¹In. The results for the ¹⁰¹Sn decay as well as those from previous work on the ¹⁰³Sn decay are discussed by comparing them to predictions obtained from shell model calculations employing a new interaction in the ⁸⁸Sr to ¹³²Sn model space.     

Synthesis and structure of (C=O→Si←O′=C′)bis(2-methyl-4-oxopyran-3-yloxy)difluoro-(λ<Superscript>6</Superscript>)siliconium

A new six-coordinate silicon compound, (C=O→Si←O′=C′)bis(2-methyl-4-oxopyran-3-yloxy)-difluoro(λ⁶)siliconium, containing two five-membered rings closed by C=O→Si coordination bonds, forms o protodesilylation trifluoro(phenyl)silane with 3-hydroxy-2-methylpyran-4-one (maltol). According to multinuclear NMR and IR spectral data and quantum-chemical calculations, the silicon atom in this compound has an octahedral environment with two cis-arranged C=O→Si bonds     

Photo- and temperature-dependent formation of tryptophan/silver nanoparticles

Research on Chemical Intermediates - Amino acid tryptophan is an advantageous reagent for preparation of biocompatible noble metal nanoparticles as promising anticancer agents. The reduction of...     

Hydrogen bonds in dimers of 3-hydroxy-2-methyl-4-pyrone. AIM analysis

According to quantum topological analysis performed at the MP2/6-311++G** level the intramolecular hydrogen bond OH⋯O=C in 3-hydroxy-2-methyl-4-pyrone (maltol) is weak and has ionic nature. This bond is broken upon formation of H-complex of maltol with phosgene and with increase the polarity of medium. The chain dimer of maltol is stabilized by weak intermolecular bonds OH⋯O=C and CH⋯O=C of ionic character, whereas the cyclic dimer by two medium in strength intermolecular hydrogen bonds OH⋯O=C. Original Russian Text ? E.P. Doronina, T.N. Aksamentova, N.N. Chipanina, S.A. Mukha, S.A. Medvedeva, 2009, published in Zhurnal Obshchei Khimii, 2009, vol. 79, No. 2, pp. 308–313.     

Determination of composition and instability constants of maltol complexes with iron(iii) ions

Complexation of maltol (MH) with Fe³⁺ ions in aqueous solutions was studied. The compositions of [FeMa]²⁺, [FeMa₂]⁺, and [FeMa₃] complexes were determined by the method of isomolar series, and their instability constants were calculated. The values of the latter were confirmed by the method of apparent deviation from the Bouger—Lambert—Beer law. An increase in the Ma : Fe³⁺ ratio from 1 to 3 decreases the instability constants of the complexes. The [FeMa₃] complex can be considered as a basis for the antianemic drug with a prolonged effect.     

Antiviral Effect of Nonfunctionalized Gold Nanoparticles against Herpes Simplex Virus Type-1 (HSV-1) and Possible Contribution of Near-Field Interaction Mechanism

The antiviral activity of nonfunctionalized gold nanoparticles (AuNPs) against herpes simplex virus type-1 (HSV-1) in vitro was revealed in this study. We found that AuNPs are capable of reducing the cytopathic effect (CPE) of HSV-1 in Vero cells in a dose- and time-dependent manner when used in pretreatment mode. The demonstrated antiviral activity was within the nontoxic concentration range of AuNPs. Interestingly, we noted that nanoparticles with smaller sizes reduced the CPE of HSV-1 more effectively than larger ones. The observed phenomenon can be tentatively explained by the near-field action of nanoparticles at the virus envelope. These results show that AuNPs can be considered as potential candidates for the treatment of HSV-1 infections.     

Two-proton radioactivity search

Two-proton radioactivity, a spontaneous breakup of elements with emission of two protons, was predicted to exist near the proton drip line by V.I. Goldansky long time ago. The recent theoretical and experimental progress in a search for such an exotic nuclear decay is reviewed. In theory, the new three-body model which treats two-proton radioactivity as a genuine three-particle nuclear decay is considered. In experiment, the first evidence for two-proton decay of ⁴⁵Fe is described. Four atoms of ⁴⁵Fe, produced at the fragment separator of GSI, decayed via particle emission with a total energy of 1.1(1) MeV and a half-life of 3.2 _?1.0 ^+2.6 ms. A possible experiment for a direct observation of two-proton emission from the ground state of ¹⁹Mg is considered for its decay in-flight. The half-life of ¹⁹Mg, as well as proton-proton correlations, might be derived from the distribution of the ¹⁹Mg decay vertices extrapolated from the measured trajectories of all fragments.     

Observation of proton radioactivity of the (21+) high-spin isomer in 94Ag

We have observed direct one-proton decay of the (21+) isomer in the N=Z nuclide 94Ag into high-spin states in 93Pd by detecting protons in coincidence with gamma-gamma correlations and applying gamma gates based on known 93Pd levels. Two decay branches have been identified, with proton energies of 0.79(3) and 1.01(3) MeV and branching ratios of 1.9(5)% and 2.2(4)%, respectively. The corresponding partial half-life values are 21(6) and 18(4) s. The Q value of the direct proton decay of the (21+) isomer was found to be 5.78(3) MeV. The very small reduced widths of the observed proton decays might reflect dominating collective configurations in the (21+) isomer, and the fine structure of the proton spectrum might indicate a strong deformation of this state.