Catalyst Type and Concentration Dependence in Catalytic Transfer Hydrogenolysis of α,β-Unsaturated Carbonyls and Nitriles Via Ammonium Formate

The catalytic reduction of a variety of α, β-unsaturated compounds into saturated analogs in the presence of other reducible moieties is described using ammonium formate as a hydrogen source. The rate dependence on the concentration of Pd-C catalyst as well as on 5% Pd-BaSO4 and Ra-Ni are also characterized.     

Zinc-Mediated Facile and Efficient Chemoselective S-Alkylation of 5-Aryl-1,3,4-oxadiazole-2-thiols in the Absence of Base

Zinc-mediated facile and efficient chemoselective S-alkylation of 5-aryl 1,3,4-oxadiazole-2-thiols in the presence of a catalytic amount of tetra butyl ammonium iodide was described. The reaction was performed under neutral conditions. The chemoselectivity of the alkylation was confirmed by NMR spectroscopy and x-ray crystallography.     

Separation and Analysis of Nucleic Acids and Their Constituents by Ion-Exclusion and Ion-Exchange Column Chromatography

The recent commercial development of high pressure liquid chromatographic instruments, and the availability of small and uniformly sized resin beads has enhanced the role of column chromatography for the rapid assay of nucleic acid components. A major advancement in the purification and analysis has been due to the recent demonstration that the ion exclusion is more or equally effective than the ion exchange as a separation principle for the resolution of purine and pyrimidine bases, nucleosides, deoxynucleosides and nucleotides^1–3. This article deals with the recent applications of separation principles that have been employed for the separation of nucleic acid constituents. The reader is referred to two review articles of Cohn for the earlier works on this subject^{4, 5}. Separations by chromatography and electrophoresis on paper and thin layers are not described here; several monographs and review articles are available in the literature^6–12.The reader is also referred to a recent methodological study for the base analysis of ribopolynucleotides by chemical tritium labeling which utilizes two dimensional chromatography on thin layers of cellulose as a separation means^{13, 14}.     

Constraining chameleon field driven warm inflation with Planck 2018 data

The European Physical Journal C - We study the Yukawa model with one scalar and one axial scalar fields, coupled to N copies of Dirac fermions, in curved spacetime background. The theory possesses...     

Design,Synthesis, and Biological Evaluation of 1,2,4-Oxadiazole-Isoxazole Linked Quinazoline Derivatives as Anticancer Agents

Russian Journal of General Chemistry - A series of novel 1,2,4-oxadiazole-isoxazole linked quinazoline compounds is designed, synthesized and screened for anticancer activity on four human cancer...     

Preparation of thalidomide nano-flakes by supercritical antisolvent with enhanced mass transfer

Thalidomide treats multiple myeloma and protracts life-span of patient, but its bioavailability is limited as it is poorly water soluble. Thalidomide nano-flakes are produced to improve the drug dissolution rate. Two nanoflake production methods are utilized for a comparative study: a supercritical antisolvent (SAS) method and a supercritical antisolvent with enhanced mass transfer (SAS-EM). SAS-EM utilizes ultrasonication to improve dispersion upon injection within the supercritical carbon dioxide. Comparative study of SAS and SAS-EM thalidomide confirmed that the application of ultrasonication improved the micro/nano particles produced by SAS. The effects of ultrasound power on the formation of thalidomide particles are examined. The particle size and morphology were characterized by SEM. The thalidomide nano-flakes produced by SAS-EM were smaller than the particles produced by SAS. Dissolution rates of the produced particles, evaluated by HPLC, demonstrated an increase in the thalidomide dissolution rate for the SAS-EM produced particles. The polymorphs and crystallinity of thalidomide particles (flakes) were observed by FTIR and XRD. In this research, the supercritical processing significantly modified the crystal formation of thalidomide from an original state of a β-polymorph to the amorphous state α-polymorph after supercritical processing.     

Primordial cosmological inflation versus local supersymmetry breaking in SUSY GUTs coupled toN=1 supergravity

We present a model for a SUSY GUT coupled toN=1 supergravity in which local supersymmetry breaks down in the gauge singlet sector. The constraints for the model to be physically acceptable are incompatible with inflation. The simultaneous breaking of local supersymmetry and gauge symmetry is proposed as a good prospect for inflation.     

EPR and optical absorption studies of vanadyl impurity in lithium hydrogen oxalate single crystal

Electron paramagnetic resonance (EPR) and optical absorption studies of vanadyl ions in lithium hydrogen oxalate monohydrate single crystal and powder are reported at room temperature. Single crystal rotations in each of the three mutually orthogonal crystalline planes, $a{b}^1$, $b^1{c}^1$ and $a{c}^1$ indicate four different vanadyl complexes. The detailed investigation of EPR spectra indicates that one of the VO^{2 +} sites (the intense one) may enter the lattice substitutionally and the other three occupy the interstitial positions. From the angular variation, the spin Hamiltonian parameters are evaluated and discussed. The optical absorption spectrum shows four bands. From the optical and EPR data, various bonding parameters are determined and the nature of bonding in the crystal is discussed.     

On the temperature Dependence of the orientational Order Parameter in the Nematic Phase of Cyanophenyl Behzoates

The orientational order parameters fot two liquid crystal materials, 4-cyanophenyl 4-butylbenzoate and 4-cyanophenyl 4-pentylbenzoate, have been derived by measuring the change in the refractive index as function of temperature. The order parameters are compared with MaierSaupe theory, and the sharpness of the transitions has been shown using the Haller's plot.