Sensitive method for the determination of rocilinostat in small volume mouse plasma by LC‐MS/MS and its application to a pharmacokinetic study in mice

A highly sensitive, specific and rapid LC‐ESI‐MS/MS method has been developed and validated for the quantification of rocilinostat in small volume mouse plasma (20 μL) using vorinostat as an internal standard (IS) as per regulatory guidelines. Sample preparation was accomplished through a protein precipitation procedure with acetonitrile. Chromatography was achieved on Prodigy ODS‐2 column using a binary gradient using mobile phase A (0.2% formic acid in water) and B (acetonitrile) at a flow rate of 0.38 mL/min. The total chromatographic run time was 4.1 min and the elution of rocilinostat and IS occurred at ~3.2 and 2.9 min, respectively. A linear response function was established in the concentration range of 0.28–1193 ng/mL in mouse plasma. The intra‐ and inter‐day accuracy and precisions were in the ranges of 3.12–8.93 and 6.41–11.6%, respectively. This novel method has been applied to a pharmacokinetic study in mice. Copyright © 2016 John Wiley & Sons, Ltd.     

Mechanistic investigation, kinetic modeling and analysis parameters of poly(3-hexylthiophene) degradation to fullerenes

Thermal degradation of Poly (3-hexylthiopene) (P3HT) was studied under nitrogen environment. Kinetic parameters of thermal degradation were determined using Vyazovkin model free method and model fitting method. Vyazovkin model free kinetic analysis is carried out to understand the variation of activation energy (E_α) required for degradation of polymer with conversion (α). Various reaction models have been tested for probable reaction mechanism using hybrid genetic algorithm (HGA). Diffusion model and nucleation & growth with n = 2/3 has prominent role in thermal decomposition of P3HT. A plausible degradation route is proposed based on the experimental details acquired from gas chromatography (GC), Raman spectroscopy, FTIR spectroscopy, powder X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Degradation of P3HT starts at around 195 °C with release of lighter units like CS. Further increase in the temperature results in detachment of the hexyl chain from P3HT and the residue obtained at 1050 °C contains fullerenes mixed with amorphous carbon.     

UV-sensitized nanomaterial semiconductor catalytic reduction of Co<Superscript>III</Superscript>(N–N)<Subscript>3</Subscript><Superscript>3+</Superscript>/nm-TiO<Subscript>2</Subscript> and Co:TiO<Subscript>2</Subscript> formation: SEM-EDX and HRTEM analyses

Interfacial electron transfer induced by 254 nm light at nanomaterial (nm) titanium dioxide/Co^III(N–N)₃ ³⁺ interface in binary mixed solvent media such as water/methanol (or 1,4-dioxane) has been probed. The distinct photo reduction of cobalt(III) complexes, Co^III(N–N)₃ ³⁺; (N–N)=(NH₃)₂, en (1,2-diamino ethane), pn (1,2-diamino propane), tn (1,3-diamino propane), and bn (1,4-diamino butane), by excited nm-TiO₂ particles: Co^III + nm-TiO₂ + hν → TiO₂ (h⁺;e⁻) + Co^III → nm-TiO₂ (h) + Co^II is solvent controlled. The electron transfer from the conduction band of TiO₂ (e⁻, CB) onto the metal centre of the complex consists of (i) electron transport from CB into surface-adsorbed species A: Co^III(N–N)₃ ³⁺ (ii) solution phase species B: Co^III(N–N)₃ ³⁺ _(sol.), accumulated at the surface of the nanoparticle. In addition, UV irradiation of Co^III(N–N)₃ ³⁺ stimulates generation of \textCo_\textaq^\textII {\text{Co}}_{\text{aq}}^{\text{II}} ion, due to charge transfer transition, in solution phase. After UV irradiation, cobalt-implanted nm-TiO₂ separated as gray ultrafine particles, which were isolated. Photo efficiency of the formation of Co^II ion was estimated and the cobalt implanted nanomaterial crystals isolated from the photolyte solutions were subjected to SEM-EDX, X-ray mapping, and HRTEM-SAED analyses. Solvent medium was found to contribute in both the formation of Co^II ion and interstitial insertion of cobalt into the lattice of nm-TiO₂.     

Unsteady double diffusive mixed convection flow over a vertically stretching sheet in the presence of suction/injection

An unsteady double diffusive mixed convection boundary layer flow over a vertically stretching sheet in the presence of suction/injection is investigated in this paper. The governing partial differential equations are reduced by applying suitable transformations to a set of nonlinear ordinary differential equations, which is solved by the Keller box method. The influence of various flow parameters on the velocity, temperature, and species concentration profiles of the fluid is studied. The effect of some problem parameters on the skin friction coefficient in the presence of suction/injection is considered.     

Computational study on the structural and surface properties of amorphous hydroxylated TiO<Subscript>2</Subscript> spherical nanoparticles

Monte Carlo simulations were carried out on amorphous titanium dioxide (TiO₂) for both bulk and hydroxylated nanoparticles with particle sizes ranging from 1 to 10 nm. The potential developed by the Matsui and Akaogi (MA) was used to model the interatomic interactions of TiO₂ in both cases (bulk and nanoparticles). Besides, Angular and Morse potentials proposed by the Tether, Cormack, Du et. al. (TCD) were introduced to model the interactions of hydroxyl groups on the TiO₂ surfaces, i.e., the Ti-O-H groups with an experimental and theoretical angles of 125 ^o . The bulk system was developed using periodic boundary conditions. The TiO₂ nanoparticles were extracted by applying a spherical cut section in the bulk TiO₂ melt structure to obtain the required size. Free valences on the nanoparticle surfaces were saturated via additional hydroxyl groups and then quenched to 300 K under free boundary conditions. The bulk and surface properties of the nanoparticles were calculated at 300 K and zero pressure and characterized via radial distribution functions, bond angle distributions, bond distances, coordination numbers, OH group concentrations and radial density profiles. In addition, to understand the difference in properties of amorphous hydroxylated TiO₂ nanoparticles and bulk amorphous TiO₂, a comparative study was done at the same thermodynamic conditions. The study shows that the bulk properties of amorphous hydroxylated TiO₂ nanoparticles are strongly size-dependent and different from those of the bulk TiO₂. As expected, increasing the particle size leads to an approach of the particle’s bulk properties to the bulk properties of the (quasi) infinite system. The size effects show that decreasing the particle size results in increasing the surface effects and surface OH group concentrations. Accordingly, small-sized TiO₂ nanoparticles have higher surface OH group concentrations and larger surface effects than large-sized TiO₂ nanoparticles. Larger surface effects result significant changes in their bond angles, bond distances, and coordination numbers. The simulation results of the surface properties reveal that the surface titanium atoms in the TiO2 nanoparticles have the capability of accommodating up to 5 hydroxyl groups. The mean surface hydroxyl group density of the amorphous TiO₂ spherical nanoparticles is estimated to be around 8.1/nm ², which lies in the range of 8–16/nm ², found by experimental and other simulation studies. Details of the modelling, simulations results and the study are presented in this paper.     

Production of thermostable multiple enzymes from Bacillus amyloliquefaciens KUB29

A strain of Bacillus amyloliquefaciens KUB29 was identified by 16S ribosomal RNA sequencing (Genbank: MF772779.1). Production of thermostable protease, amylase and lipase were done by the isolated strain. The produced enzymes were partially purified by ammonium precipitation followed by dialysis process. Protease and lipase enzymes are effectively used in bio-oil extraction from proteinaceous sample followed by transesterification to produce methyl ester. Amylase enzyme is widely used in food and laundry industry. The produced enzymes are active at thermophilic condition of 55 °C. Use of these enzymes in biofuel production process will make the process cleaner and greener.     

Microlocal Analysis of the Doppler Transform on R<Superscript>3</Superscript>

The Doppler transform of a vector field $F = (f_1,f_2,f_3)$ on $\mathbb{R}^3$ is defined by \[\displaystyle\mathcal{D}F(x,\omega) = \sum_j\int_\mathbb{R} \omega_j f_j(x+t\omega)\, dt~,\] where $x\in \mathbb{R}^3$ and $\omega \in S^2$ specifies the direction of a line passing through $x$. In practical applications, $\mathcal{D}F$ is known only for a small subset of lines in $\mathbb{R}^3$. In this article, we deal with the case of $\mathcal{D}F$ restricted to all lines passing through a fixed smooth curve. Using techniques from microlocal analysis, we study the problem of recovering the wavefront set of $\mbox{curl}(F)$ from that of the restricted Doppler transform of $F$.     

Spontaneous ratchet effect in a granular gas

The spontaneous clustering of a vibrofluidized granular gas is employed to generate directed transport in two different compartmentalized systems: a granular fountain in which the transport takes the form of convection rolls, and a granular ratchet with a spontaneous particle current perpendicular to the direction of energy input. In both instances, transport is not due to any system-intrinsic anisotropy, but arises as a spontaneous collective symmetry breaking effect of many interacting granular particles. The experimental and numerical results are quantitatively accounted for within a flux model.     

Do fluorescence decays remitted from tissues accurately reflect intrinsic fluorophore lifetimes?

Fluorescence spectroscopy and imaging methods, including fluorescence lifetime sensing, are being developed for noninvasive tissue diagnostics. The purpose of this study was to identify and quantify those factors affecting the accurate recovery of fluorophore lifetimes from inhomogeneous tissues in vivo. A Monte Carlo code was developed to numerically simulate time-resolved fluorescence measurements on layered epithelial tissues. Simulations were run with experimental parameters matching previously reported clinical studies in the gastrointestinal tract. The results demonstrate that variations in fluorescence decay time as large as those detected clinically between normal and premalignant tissues (approximately 2 ns) could be simulated by variations in tissue morphology or biochemistry, even when intrinsic fluorophore lifetimes were held constant.