A novel fluorescent "turn-on" chemosensor for nanomolar detection of Fe(III) from aqueous solution and its application in living cells imaging

An electronically active and spectral sensitive fluorescent “turn-on” chemosensor (BTP-1) based on the benzo-thiazolo-pyrimidine unit was designed and synthesized for the highly selective and sensitive detection of Fe³⁺ from aqueous medium. With Fe³⁺, the sensor BTP-1 showed a remarkable fluorescence enhancement at 554 nm (λex=314 nm) due to the inhibition of photo-induced electron transfer. The sensor formed a host-guest complex in 1:1 stoichiometry with the detection limit down to 0.74 nM. Further, the sensor was successfully utilized for the qualitative and quantitative intracellular detection of Fe³⁺ in two liver cell lines i.e., HepG2 cells (human hepatocellular liver carcinoma cell line) and HL-7701 cells (human normal liver cell line) by a confocal imaging technique

Theoretical aerothermal concepts for configuration design of hypersonic vehicles

Convection coefficients and heat fluxes due to aerodynamic heating on critical surfaces of hypersonic vehicle are obtained analytically. The applicability of recovery temperature for stagnation regions is discussed. Convection coefficient for the bicurvature forward stagnation region is obtained directly from 2-D stagnation region correlation, using the two principal radii of curvatures. Convective heat flux to swept-back leading edge (SBLE) surface is obtained from the 2-D stagnation region and flat plate heat fluxes, using the respective velocity vector components. Results reveal the concepts of temperature-minimised-sweepback, and the thermally-benign sharp SBLE effect at high sweepback angles.© Elsevie

Scale-invariant entropy-based theory for dynamic ordering

Dynamically Ordered self-organized dissipative structure exists in various forms and at different scales. This investigation first introduces the concept of an isolated embedding system, which embeds an open system, e.g., dissipative structure and its mass and/or energy exchange with its surroundings. Thereafter, scale-invariant theoretical analysis is presented using thermodynamic principles for Order creation, existence, and destruction. The sustainability criterion for Order existence based on its structured mass and/or energy interactions with the surroundings is mathematically defined. This criterion forms the basis for the interrelationship of physical parameters during sustained existence of dynamic Order. It is shown that the sufficient condition for dynamic Order existence is approached if its sustainability criterion is met, i.e., its destruction path is blocked. This scale-invariant approach has the potential to unify the physical understanding of universal dynamic ordering based on entropy considerations. (C) 2014 AIP Publishing LLC

Optimization of micro-heat sink based on theory of entropy generation in laminar forced convection

The entropy generation ((gen)) due to fluid friction and convective heat transfer is studied en-route the microscale. The (gen) for water-flow through a circular tube for the constant wall heat flux boundary condition is estimated. The number of tubes (N) en-route the microscale is increased by correspondingly decreasing each tube diameter, for fixed total mass flow rate and the total heat flow rate is also kept constant. There exists an optimum tube diameter (D-N,D-opt) and a corresponding optimum natural number N (N-opt) at which, the sum-total (gen) is minimum. Criterion for D-N,D-opt is obtained in terms of Reynolds number and a modified Brinkman number, which shows that D-N,D-opt depends only on the total heat flow rate. Unlike other reported studies, the fluid temperature in the denominator of the entropy generation terms is considered as local and variable. The difference in (gen) based on reported studies and this investigation increases significantly especially towards the microscale

Microwave assisted one-pot synthesis of nitrogen and oxygen containing heterocycles from acyl Meldrum’s acid

745-747One-pot syntheses of biologically active nitrogen and oxygen containing heterocyclic compounds such as uracils and thiouracils and 1,4-benzothiazines, 4-methylcoumarins and 4H-1,4-dihydropyridines, using acyl Meldrum’s acids are reported

Variations in gas properties in laminar micro-convection with entrance effect

The present work investigates the influence of property variations of air in laminar forced convection with entrance effect. Two-dimensional micro-sized geometry (with axisymmetry) with constant wall heat flux boundary condition is considered to predict flow behaviour and thermal development. The continnum-based conservation equations are numerically solved to account for non-rarefaction scaling effects due to variations in fluid properties. At the microscale, results for Nusselt number show significant deviation from conventional theory that does not consider additional mechanisms that surface. The effect of property variation in Graetz problem for low subsonic flow is also studied.© Elsevie

Study of black hole as dissipative structure using negentropy

The area of the event horizon of a black hole (A(eh)) is so far linked only with its entropy (S-BH). In this theoretical investigation, it is shown that relating A(eh) only to S-BH is inadequate, because Aeh is linked to the black hole's negentropy, which encompasses its entropy. Increasing A(eh) of black holes that grow now follows from the negentropy theorem (NET) and also from the well-known area theorem. The decreasing A(eh) of black holes that decay follows from the converse to NET and is not a violation of the area theorem. The corollary to NET is proved for the case when two dissipative structures merge, which is the basis for the coalescence of black holes. The converse of corollary to NET explains negentropy loss due to splitting of a dissipative structure. When applied to black hole explosion (i.e., splitting into an infinite number of parts), converse of corollary to NET reduces to converse of NET. The entropy/energy ratio of the exported Hawking radiance from black holes contributes to the entropy increase of the universe. These aspects justify the consideration of black holes as thermodynamic dissipative structures

Estimation of Rabeprazole Sodium in tablet dosage form by rapid isocratic reversed phase high performance liquid chromatography using volatile buffer additives

992-994A simple, rapid and reproducible reverse phase high performance liquid chromatographic (RP-HPLC) assay method for determination of Rabeprazole Sodium (RS) in solid dosage form (20 mg) has been developed. Chromatographic separation was performed on YMC C18, ODS-AM stainless steel column (250 mm x 4.6 mm ID; particle size 5m). Mobile phase comprised of 50 m M ammonium acetate in water (pH 8) with ammonia and methanol. Detection was performed using PDA detector. Recovery of RS in tablets was 95.5-96.8%. Chromatographic response of the analyte (100-500 mg/ml) was linear with correlation coefficient more than 0.99. Runtime of the method is very short and mobile phase additives used are volatile that are also suitable for mass spectrometry analysis. Therefore, this method could be used for routine quality control analysis and in bio-analytical work

Microwave assisted rapid and efficient synthesis of aryl methyl ketones and β-keto esters using Meldrum’s acid

823-825Microwave mediated rapid and efficient synthesis of aryl methyl ketones and β-keto esters from acyl Meldrum’s acid by hydrolysis and alcoholysis, respectively, has been reported

Fluid friction in incompressible laminar convection: Reynolds' analogy revisited for variable fluid properties

The Reynolds' analogy between the Stanton number (St) and the skin friction coefficient (cf) is popularly believed to hold when St increases with increasing cf, for simple situations. In this investigation, the validity of Reynolds' analogy between St and cf for micro-convection of liquids with variations in fluid properties is re-examined. It is found that the Sieder-Tate's property-ratio method for obtaining Nusselt number corrections is theoretically based on the validity of Reynolds' analogy. The inverse dependence of Reynolds number and skin friction coefficient is the basis for validity of the Reynolds' analogy, in convective flows with fluid property variations. This leads to the unexpected outcome that Reynolds' analogy now results in St increasing with decreasing cf. These results and their analyses indicate that the validity of Reynolds' analogy is based on deeper foundations, and the well-known validity criterion is a special case