Kinetics of the esterification of palmitic acid with isobutyl alcohol

Kinetics of the sulfuric acid catalyzed esterification of palmitic acid with isobutyl alcohol has been studied and reviewed critically. A theoretical rate equation is derived by the following reaction mechanism: (1) The reaction of sulfuric acid and isobutyl alcohol produces isobutyl sulfuric acid which acts as a catalyst; (2) Palmitic acid is protonated by the catalyst to form the reaction intermediate; and (3) The esterification proceeds reversibly. The experimental results are consistent with this rate equation.     

Antiviral phytochemicals identification from Azadirachta indica leaves against HCV NS3 protease: an in silico approach

Hepatitis C virus (HCV) is a major health problem across the world affecting the people of all age groups. It is the main cause of hepatitis and at chronic stage causes liver cirrhosis and hepatocellular carcinoma. Various therapeutics are made against HCV but still there is a need to find out potential therapeutics to combat the virus. The goal of this study is to identify the phytochemicals of Azadirachta indica leaves having antiviral activity against HCV NS3 protease through molecular docking and simulation approach. Results show that the compound 3-Deacetyl-3-cinnamoyl-azadirachtin possesses good binding properties with HCV NS3/4A protease. It can be concluded from this study that Deacetyl-3-cinnamoyl-azadirachtin may serve as a potential inhibitor against NS3/4A protease.     

Inequalities for entire functions of exponential type satisfying f(z) \equiv e^{i\gamma } e^{i\tau z} \overline {f(\bar z)}

Let f be an entire function of exponential type satisfying the condition $ f(z) \equiv e^{i\gamma } e^{i\tau z} \overline {f(\bar z)} $ for some real γ. Lower and upper estimates for ∫ _?∞ ^∞ |f′(x)| ^p dx in terms of ∫ _?∞ ^∞ |f(x)| ^p dx, for such a function f belonging to L ^p (R), have been known in the case where p ? [1, ∞) and γ = 0. In this paper, these estimates are shown to hold for any p ? (0, ∞) and any real γ.     

Synthesis and antioxidant activity study of carbothioamide and their corresponding thiazole derivatives

A novel series of 5-(p-(prop-2-ynyloxy)phenyl)-3-aryl-4,5-dihydropyrazole-1-carbothioamides 2a-f and functionalized 2-(3-(aryl)-5-(4-(prop-2-ynyloxy)phenyl)-4,5-dihydropyrazol-1-yl)-4-(3-arylsydnone-4-yl)thiazoles 4a-l were synthesized. The newly synthesized compounds were elucidated by analytical and spectral analysis. From the single-crystal X-ray diffraction method, it was observed that 2d crystallizes in a monoclinic crystal system with P21/n space group. The compounds 2d crystallized with cell parameters a = 15.0614 (19) Å, b = 6.0805 (7) Å, c = 20.903 (7) Å, α = 114.136 (6)^o, β = 110.709 (14) ^o, γ = 96.553 (5) ^o, V = 1790.6 (4) ų, Z = 4. From the Hirshfeld surface computational method, the major intercontacts present in these molecules are H…H (31.6%), C…H (18.2%) and S…H (12.2%), respectively. The newly synthesized compounds were tested for their ability to bleach 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical using DPPH scavenging assay. Among the synthesized compounds carbothioamide compounds 2c (90.7%) and 2b (89.8%) exhibited good DPPH scavenging activity compared to the rest of the compounds. Most of the synthesized carbothioamide molecules ( 2a-f ) found to be potent compared to the thiazole derivatives ( 4a-l ).     

Antihaemorrhagic potentials of Fagonia cretica against Naja naja karachiensis (black Pakistan cobra) venom

Plants have been extensively used as a remedy for the treatment of snake bites. The aim of this study was to determine the antivenom potentials of methanolic extract from the aerial parts (leaves and twigs) of Fagonia cretica L. on a haemorrhage induced by venom from Naja naja karachiensis. The haemorrhagic response of venom was dose dependent from 0.1 to 4.0?μg per 1.5?μL phosphate buffer saline (PBS) on vitelline veins of fertilised hens' eggs in their shells. The extract effectively eliminated and neutralised, in a dose-dependent manner, the haemorrhagic activity of snake venom. The minimum effective neutralising dose of F. cretica extract was found to be 15?μg per 1.5?μL PBS. The extract possesses potentials as haemorrhagic inhibitor against snake venom compared to the standard antiserum and various plants reported in the literature. This study also provides a scientific base for the use of F. cretica in traditional medicine for the treatment of snake bite.     

Effect of foreign ions for the determination of metal ion in the presence of surfactants

Aluminum is the third most abundant metal in the Earth’s crust. Despite its ubiquitous nature it is present in small amount in living organisms. Aluminum toxicity has been implicated in the pathogenesis of renal distinct clinical syndromes, including progressive and fatal encephalopathy and bone diseases. In the present study, Al was selected for the analysis by complexometric method. This method was based on the formation of a red colored ternary complex by the reaction of Aluminum with Aluminon (Aurin tricarboxylic acid triammonium salt) in the presence of micellar medium. The ternary complex of Aluminum with the surfactant Triton X-100 shows a maximum absorbance at 530 nm wavelength at pH 4.0 while with the sodium dodecyl sulfate it shows a maximum absorbance at 525 nm and at pH 5.0. The reaction was proceeded by the variation in pH and concentrations of surfactants, aluminon, aluminum. Their effects on the reaction of aluminum with aluminon complex in micellar media were recorded by UV-visible spectrophotometer. The reaction was found to be extremely rapid at room temperature. The system obeys Lambert Beer’s law between 0.24 and 21.74 μg/mL concentrations with Triton X-100. The values of slope, intercept and correlation coefficients were 0.07, 0.348 and 0.989, respectively. The concentration varied between 0.24 and 24.14 μg/mL with sodium dodecyl sulfate and the values of slope, intercept and correlation coefficients were 0.029, 0.148 and 0.962, respectively. The foreign ion effect was also tested by keeping the constant concentration of metal ion and determining its concentration in the presence of different foreign ions. The method was also applied for the determination of Al(III) in pharmaceutical formulations and water samples, which showed an excellent resemblance between reported and obtained results.     

Pharmaceutical physical form characterisation with fast (>200 °C min<Superscript>−1</Superscript>) DSC heating rates

Differential scanning calorimetry (DSC) has many applications during preformulation screening of new drug candidates, but definitive assignment of peaks to specific events in the sample is difficult without supplementary data from other techniques. To some extent these problems can be overcome by running multiple experiments at different heating rates. Typically 2 and 20 °C min⁻¹ are indicated. However, modern instruments are capable of achieving much faster heating rates (up to 750 °C commercially); with this extended range comes a new capacity for investigating the physical form of materials. Here, the use of fast DSC heating rates for materials characterisation is explored, focussing on determination of melting temperatures, glass formation and polymorph screening.     

Orientation of a dispersion of kaolinite flowing in a jet

Orientational alignment in a dilute dispersion of kaolinite particles has been investigated in a flow pattern that combines both shear and elongational stress, namely flow at a jet created by a 2 mm diameter nozzle inserted in a 6 mm diameter pipe. Spatially-resolved X-ray diffraction with synchrotron radiation permits detailed maps of the alignment to be deduced and compared with fluid mechanics calculations of the flow. The angular distribution of diffracted intensity from a given position in the pipe provides information about the orientation distribution of the particles. This is quantified and presented in terms of order parameters. The cone-shaped nozzle provides a jet of liquid giving a high degree of alignment of the particles that is uniform along lines across the conical section and constant in the small straight-sided region at the exit of the nozzle. The vortex motion that arises from the flow with a modest Reynolds number could be determined as well as the tendency for some particles to align with their large faces perpendicular to the overall flow direction at the flat surface of the nozzle outlet.     

Gravitational Collapse with Heat Flux and Gravitational Waves

In this paper, we investigated the cylindrical gravitational collapse with heat flux by considering the appropriate geometry of the interior and exterior spacetimes. For this purpose, we matched collapsing fluid to an exterior containing gravitational waves.The effects of heat flux on gravitational collapse are investigated and matched with the results obtained by Herrera and Santos (Class. Quantum Gravity 22:2407, 2005).     

Computation of the Delta in Multidimensional Jump-Diffusion Setting with Applications to Stochastic Volatility Models

We study the robustness of options prices to model variation in a multidimensional jump-diffusion framework. In particular, we consider price dynamics in which small variations are modeled either by a Poisson random measure with infinite activity or by a Brownian motion. We consider both European and Exotic options and we study their deltas using two approaches: the Malliavin method and the Fourier method. We prove robustness of the deltas to model variation. We apply these results to the study of stochastic volatility models for the underlying and the corresponding options.