Vibrationally resolved photoelectron angular distributions for H2

The photoelectron asymmetry parameter, β, is reported for individual vibrational levels of H₂⁺(X²Σ_g⁺) formed by photoionization of H₂(X¹Σ_g⁺) at wavelengths of 736, 584, 461 and 304 Å. At 584 Å, β, exhibits a monotonic increase with vibrational quantum number (decreasing photoelectron kinetic energy) confirming the trend predicted by Itikawa.     

ULTRAVIOLET-ENHANCED REACTIVATION OF HERPES VIRUS IN HUMAN TUMOR CELLS

Abstract —Virus-host cell interactions may be investigated by study of the enhancement of infectivity of ultraviolet (UV)-irradiated virus obtained by UV-irradiating the host cell [ultraviolet reactivation (UVR)]. This phenomenon was studied with Herpes simplex virus and normal (embryonic lung) and malignant (HeLa) human cells. Although the lung cells displayed no UVR, both the HeLa cells and a Sendai-virus carrier culture of HeLa cells demonstrated UVR capabilities. This UVR persisted at equal or increased levels for at least 24 h. Since the lung cells and HeLa cells have similar host-cell-reactivation (HCR) abilities, the differences in UVR suggests that UVR and HCR may operate by different mechanisms.     

The preparation,phase relationships,and Eu-151 Mössbauer spectroscopy of europium tungsten bronzes and related phases

Crystal chemistry and phase relations for the bronze-forming region of the EuWO system have been investigated. A bronze Eu_xWO₃ is stable up to 1000°C when x ? 0.125 and in the region 0.085 ? x ? 0.125 the symmetry is cubic. A tetragonal bronze exists at x = 0.05, and an orthorhombic bronze with a structure closely related to the orthorhombic form of WO₃ exists below x = 0.01. Mössbauer spectra at room temperature and at 80 K indicate that in all these phases the europium is highly ionized as Eu(III) with no electron localization to give (EuII) even at low values for x. The decomposition products of the bronzes have been established, and the Mössbauer parameters for the highly nonstoichiometric tungstates Eu_xWO₄ were determined. Both Eu(II) and Eu(III) resonances were obtained, and a cation vacancy model for Eu_xWO₄ was found to fit the data best. In conformity with the foregoing data, a sample of composition “Eu₂W₂O₇” was found not be be a pyrochlore but to comprise a mixture of Eu₆WO₁₂, Eu_xWO₄, and W. The phase relationships for the europium bronze system Eu_xWO₃ are compared with those of other ionic bronzes Na_xWO₃, Li_xWO₃, and Al_xWO₃.     

The polymorphic transformations of cobalt molybdate

Polymorphic transformations of CoMoO₄ were studied by means of high temperature X-ray measurements within the temperature range 25–1200°C. On heating phase a obtained from low temperature modification b a new modification a′ was discovered. Phase a obtained by thermal decomposition of solvated α-CoMoO₄ shows different behaviour. At 700–930°C depending on the conditions of preparation it transforms irreversibly into still another modification a″. On cooling, a mixture of phases a + a″ is obtained, the presence of a″ being responsible for the explosionwise transition into b, observed around the room temperature.     

Boundary phase stability and critical phenomena in higher order solid solution systems II

The thermodynamic treatment of double-pseudobinary solutions of the type (A _xB_y) _{r o}(M _uN_v) _{s o} presented in a preceding publication was extended to include the conditions defining the critical points for the asymmetric case (r _os _o) and approximations for the spinodal and binodal surface near the critical solution point.Closed solutions for the coordinates of the critical points were obtained only for systems with ideal mixing behavior, and the isothermal binodal and spinodal near the critical solution point in such systems are adequately approximated by circles and ellipses, respectively. An axes ratio of is nearly independent of the relative sublattice abundance and the major effect of changes in the ratios _o/r _o is a rotation of the binodal by an angle tg .The principal features of nonideal regular systems for temperatures close to the critical solution point are described by expressions derived from small term expansions of the conditional equations, but generalizations are not possible to the same extent as for the case with ideal boundary systems. The results are discussed and the application of the equations demonstrated on model examples.Mit 6 Abbildungen     

Evaluation of a carbon-rod atomizer for routine determination of trace metals by atomic-absorption spectroscopy applications to analysis of lubricating oil and crude oil

A carbon-rod atomizer (CRA) fitted with a 'mini-Massmann' carbon rod was evaluated for routine analysis of petroleum and petroleum products for trace metal content by atomic-absorption spectroscopy. Aspects investigated included sensitivity, detection limit, effect of solvent type, and interferences. The results of analysis of oil samples with this technique were compared with those obtained by other techniques. Metals studied were silver, copper, iron, nickel, and lead. Sensitivity and detection limit values obtained with the CRA were similar to those obtained with the carbon-filament atomizer. Strong 'solvent effects' were observed as well as interference by cations. On the basis of this study, design changes for the CRA are suggested, with the object of minimizing 'solvent effects' and interferences, increasing the atomization efficiency, and increasing the residence time of the atomic vapour in the optical path of the instrumental system.     

Electron-impact and thermal fragmentation patterns of some perfluoroalkylene-linked aromatic and heteroaromatic compounds

The pyrolysis of some perfluoroalkylene-linked aromatic and heteroaromatic polymer precursors and a poly(1,3-phenylenehexafluorotrimethylene) has been studied using a combined pyrolysis-gas chromatographic-mass spectrometric method. Whereas the electron-impact induced fragmentations of the polymer precursors are almost exclusively controlled by cleavage β to the aromatic or heteroaromatic ring, thermolysis of these compounds yields products whose formation is consistent with the occurrence of primary cleavage processes that are not confined β to the ring.     

Reaction of β-amino-α,β-unsaturated esters and amides with aryl diazonium salts : Synthesis of cinnoline derivatives

Conjugated esters and amides react with aryldiazonium salts at room temperature (MeCN) to form the corresponding iminium hydrazone derivatives, which can be thermally cyclized to cinnoline-3-esters and cinnoline-3-amides. In general the intermediate iminium salts derived from the enamine amides cyclize faster than those from the enamine esters. Furthermore, the ease of cyclization depends upon the structure of the base-component of the enamine ester or the amide and the substituent in the aryl moiety of the diazonium salt. The configurational structure of the iminium hydrazones, studied by NMR spectroscopy, has been shown to involve H-bonding of the hydrazonyl N-H with the ester or the amide CO group.