An Unusual S-and N-Alkylation of Mercapto Substituted Heterocycles With O,O-Dialkyl Chlorophosphate/Thiophosphate

The reaction of different mercapto substituted heterocycles with o,o-dialkyl chlorphosphate or thiophosphates, gave the corresponding S- and N- alkylated derivatives instead of the expected phosphorylated products.     

The efect of the couple stress parameter and Prandtl number on the transient natural convection flow over a vertical cylinder

An analysis is performed to study transient free convective boundary layer flow of a couple stress fluid over a vertical cylinder, in the absence of body couples. The solution of the time-dependent non-linear and coupled governing equations is carried out with the aid of an unconditionally stable Crank–Nicolson type of numerical scheme. Numerical results for the steady-state velocity, temperature as well as the time histories of the skin-friction coefcient and Nusselt number are presented graphically and discussed. It is seen that for all flow variables as the couple stress control parameter, Co, is amplified, the time required for reaching the temporal maximum increases but the steady-state decreases.     

Phase transition studies in symmetric dimeric liquid crystals

As a part of the systematic studies on symmetric liquid crystal dimer homologous series, α,ω-bis-(4-n-alkylaniline benzylidene-4′-oxy) alkanes, (referred to as m.OnO.m with m = 3, 4, and 5; and n = 8, 9, and 10), we present in this article the nature of phase transitions across isotropic–nematic and nematic–smectic-A (N–SmA) phases exhibited by the just mentioned compounds. The methods employed are differential scanning calorimetry and dilatometry. The compounds studied were 3.O8O.3, 4.O8O.4, and 5.O8O.5; and 3.O9.03, 5.O9O.5, 3.O10O.3, 4.O10O.4, and 5.O10O.5. Different from the case of their corresponding monomers, all these compounds exhibit a nematic phase only with the exception of 5.O8O.5 which exhibits a SA phase in addition to the nematic phase. The phase transitions viz., isotropic–nematic transitions studied in all these compounds were confirmed to be of first-order nature, whereas the N–SmA transition exhibited by the compound 5.O8O.5 only was found to be of second-order nature. We also report in this article the calculated density jumps, thermal expansion coefficient maxima, and pressure dependence of transition temperatures which are analyzed in the light of the available literature data.     

Observation of high spin levels in131Cs from131Ba decay

The γ- and conversion electron spectra following¹³¹Ba ε-decay are investigated, using HPGe detector and mini-orange electron spectrometer. Attention is particularly focussed on identifying weak transitions associated with low energy high spin levels in¹³¹Cs level scheme earlier inferred in reaction studies but not yet observed in¹³¹Ba decay. Our experiment identifies 15 new gammas and 6 new conversion lines in this decay. Internal conversion coefficients and multipolarities of several transitions are determined. Five new levels (3 with I^π = 7/2⁺ and one each with I^π 9/2⁺ and 11/2⁻) are introduced in the¹³¹Cs level scheme based on our observations taken together with the results from reaction studies. Spin-parity assignments to a few other levels are also suggested     

Sol-Gel Synthesis of Nanocrystalline PZT Using a Novel System

A simple system has been developed for the preparation of lead zirconate titanate, Pb(Zr _x Ti_{1 – x} )O₃ powders by sol-gel process. To achieve stable and homogeneous precursor solutions, chelating ligands such as acetic acid and acetylacetone have been used for the chemical modification of titanium and zirconium starting precursors. Phase-pure PZT powders were obtained, through a pyrochlore-free pathway, from the amorphous xerogel after heat treatment at 600°C. The formation of the crystalline phase, compositional homogeneity, sinterability, dielectric and piezoelectric characteristics of PZT are reported.     

A one-pot access to pyridine/benzo fused cyclododecanes via multi-component tandem reactions

A facile syntheses of novel poly-substituted pyridine/benzo fused cyclododecane hybrid heterocycles have been achieved through one-pot multi-component tandem strategy employing cyclododecanone, aromatic aldehydes and malononitrile.     

Tilianin: A Potential Natural Lead Molecule for New Drug Design and Development for the Treatment of Cardiovascular Disorders

Cardiovascular disorders (CVDs) are the leading risk factor for death worldwide, and research into the processes and treatment regimens has received a lot of attention. Tilianin is a flavonoid glycoside that can be found in a wide range of medicinal plants and is most commonly obtained from Dracocephalum moldavica. Due to its extensive range of biological actions, it has become a well-known molecule in recent years. In particular, numerous studies have shown that tilianin has cardioprotective properties against CVDs. Hence, this review summarises tilianin’s preclinical research in CVDs, as well as its mechanism of action and opportunities in future drug development. The physicochemical and drug-likeness properties, as well as the toxicity profile, were also highlighted. Tilianin can be a natural lead molecule in the therapy of CVDs such as coronary heart disease, angina pectoris, hypertension, and myocardial ischemia, according to scientific evidence. Free radical scavenging, inflammation control, mitochondrial function regulation, and related signalling pathways are all thought to play a role in tilianin’s cardioprotective actions. Finally, we discuss tilianin-derived compounds, as well as the limitations and opportunities of using tilianin as a lead molecule in drug development for CVDs. Overall, the scientific evidence presented in this review supports that tilianin and its derivatives could be used as a lead molecule in CVD drug development initiatives.