Can φ-photoproduction easily reveal the pole-cut nature of the pomeron? Addendum to the paper “pomeron factorisation and the reaction γN - φN”

It is commonly believed that γN → ΦN is a good reaction to study the Pomeron. By considering the existing data and the various properties associated with a pole, we show that it would be experimentally hard for this reaction to reveal departures from a pole-type Pomeron. For testing factorization and relative reality of all amplitudes, our claim uses the experimentally indicated approximate s-channel meson-helicity conservation and also, almost pure nature parity in the crossed channel.     

Comparative Bioactive Studies Between Wild Plant and Callus Culture of Tephrosia tinctoria Pers.

Tephrosia tinctoria, a perennial under shrub of Fabaceae family, is endemic to Western Ghats. In this study, friable whitish yellow callus was developed after 45 days using Murashige and Skoog medium supplemented with 2,4-dichlorophenoxyacetic acid (2.0 mg/l)?+?6-benzylaminopurine (0.5 mg/l) in various explants of T. tinctoria. The ethyl acetate extracts of leaf (LE), stem (SE), and root (RE) were compared with leaf (LCE), stem (SCE), and root (RCE) derived callus, for antioxidant and antiproliferative activities. The SE possessed the highest phenolic and flavonoid content among all the extracts tested and showed a significant antioxidant assays. The study of anticancer activity on human hepatocellular carcinoma (HepG2) cell line revealed that the callus extracts especially RCE possessed significant inhibition of cell growth (IC₅₀ 20 μg/ml) at 72 h treatment period on analysis with MTT assay. The apoptotic cell death was observed through DNA fragmentation analysis in HepG2 cells treated with the T. tinctoria extracts. The gas chromatography–mass spectrometry finger printing profile showed that more than 60 % percentage of metabolites are similar in both SE and SCE. The higher percentage area of antioxidant compound (stigmast-4-en-3-one) was observed in SE (2.01 %) and higher percentage area of anticancer compound (phenol, 2,4-bis(1,1-dimethylethyl)) in SCE (0.91 %). In addition to that, callus extracts contain squalene, which is used for target deliver and also used as anticancer drug. Thus, the present study revealed that the T. tinctoria has potent antioxidant and antiproliferative activity and the callus culture can be used for the production of the bioactive compounds due to the endemic nature of this plant.     

Au36(SPh)23 nanomolecules

A new core size protected completely by an aromatic thiol, Au(36)(SPh)(23), is synthesized and characterized by MALDI-TOF mass spectrometry and UV-visible spectroscopy. The synthesis involving core size changes is studied by MS, and the complete ligand coverage by aromatic thiol group is shown by NMR.     

A stochastic model for solidification

A 3-dimensional (2-space, 1-time) model relating the diffusion of heat and mass to the kinetic processes at the solid-liquid interface, using a stochastic approach is presented in this paper. This paper is divided in two parts. In the first part the basic set of equations describing solidification alongwith their analysis and solution are given. The process of solidification has a stochastic character and depends on the net probability of transfer of atoms from liquid to the solid phase. This has been modeled by a Markov process in which knowledge of the parameters at the initial time only is needed to evaluate the time evolution of the system. Solidification process is expressed in terms of four coupled equations, namely, the diffusion equations for heat and mass, the equations for concentration of the solid phase and for rate of growth of the solid-liquid interface. The position of the solid-liquid interface is represented with the help of a delta function and it is defined as the surface at which latent heat is evolved. A numerical method is used to solve the equations appearing in the model. In the second part the results i.e. the time evolution of the solid-liquid interface shape and its concentration, rate of growth and temperature are given.     

Ionic conductivity of poly(2-vinyl pyridinium) salt in solid state

The preparation, characterization and conductivities of poly(2vinylpyridine), P-2VP and its fluoride derivative are reported here. The polymer P-2VP was prepared by thermal polymerization of 2vinylpyridine, 2VP and its salt, by acidification with HF. The formation of P-2VP salt was confirmed by IR and ¹H NMR techniques. Conductivities were determined from 30 to 110 °C in solid state. The addition of F⁻ ion increases the ionic conductivity of the polymer dramatically. The P-2VP-HF behaves as an intrinsic conducting polymer. The determination of the molecular mass of P-2VP and P-2VP-HF indicated that 95% of pyridine molecule was hydrofluorinated.     

Thermal studies of copolymers of styrene and maleic anhydride

Copolymers of styrene and maleic anhydride prepared by a charge transfer mechanism have been studied thermally by thermogravimetry and differential scanning calorimetry. The copolymers degrade in two stages; the first stage accounts for about 85% of the degradation. Incorporation of maleic anhydride to styrene decreases the thermal stability of the later. Differential scanning calorimetric studies show two exotherms between 300° to 500 °C. Glass-transition temperatures for the copolymers are lower than that of polystyrene.     

Effects of iron(III) chloro complexes on the polymerization of styrene

The polymerization of styrene initiated by 2,2′-azobisisobutyronitrile has been studied in N,N-dimethylformamide solution at 60°C in the presence of hexakis(N,N-dimethylformamide) iron(III) tetrafluoroborate alone, and also in the presence of added lithium chloride. The presence of Fe(DMF)₆³⁺ ions in the polymerizing systems caused retardation, but iron(III) chloro complexes produced well defined inhibition periods. Velocity constants at 60°C for polystyryl radicals towards Fe(DMF)₆³⁺, Fe(DMF)₅Cl²⁺, Fe(DMF)₄Cl₂⁺, and FeCl₄^? ions were calculated to be 847, 4.15 × 10⁴, 6.55 × 10⁴, and 3.14 × 10⁴ l./mole-sec, respectively. Values of the initiator efficiency f for most systems investigated ranged from 0.59 to 0.62.