Synthesis of RAFT-Mediated Amphiphilic Graft Copolymeric Micelle Using Dextran and Poly (Oleic Acid) toward Oral Delivery of Nifedipine

A novel, pH-responsive supramolecular graft copolymeric micelle, composed of dextran and poly (oleic acid), has been synthesized through reversible addition fragmentation chain transfer polymerization with controlled M_n and narrow polydispersity. The structural properties of the copolymer have been studied using FTIR and ¹H NMR spectral analyses. Critical micelle concentration (CMC) has been determined fluorometrically and conductometrically. The copolymer shows pH responsive micellar stability, which has been confirmed using DLS study. Dextran-g-OA copolymer demonstrates spherical morphology at CMC, while rod-like assembly has been evidenced beyond CMC that is probably because of the structural alteration of copolymeric chains at higher copolymer concentration. Dextran-g-OA is noncytotoxic toward MG-63 cells. As the self-assemble nature of copolymer micelle promotes the oral administration of hydrophobic drugs, nifedipine (NFD, a hydrophobic drug) has been used as model drug that has been encapsulated substantially into the core of the micelle. The copolymer releases the loaded NFD at a much slower rate in simulated gastric fluid (pH 1.2) and relatively faster in simulated intestinal fluid (pH 7.4) with a cumulative release of ~95% within 24 h, suggesting an ideal candidate as nifedipine carrier. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2354–2363     

Validated high-performance thin-layer chromatographic—densitometric method for the isolation and standardization of ayapanin in Ayapana triplinervis

JPC – Journal of Planar Chromatography – Modern TLC - A simple, rapid, quantitative, and validated high-performance thin-layer chromatographic (HPTLC) method has been developed for the...     

Intrinsically Low Thermal Conductivity and High Carrier Mobility in Dual Topological Quantum Material,n-Type BiTe

A challenge in thermoelectrics is to achieve intrinsically low thermal conductivity in crystalline solids while maintaining a high carrier mobility (μ). Topological quantum materials, such as the topological insulator (TI) or topological crystalline insulator (TCI) can exhibit high μ. Weak topological insulators (WTI) are of interest because of their layered hetero-structural nature which has a low lattice thermal conductivity (κ_lat). BiTe, a unique member of the (Bi₂)_m(Bi₂Te₃)_n homologous series (m:n=1:2), has both the quantum states, TCI and WTI, which is distinct from the conventional strong TI, Bi₂Te₃ (where m:n=0:1). Herein, we report intrinsically low κ_lat of 0.47–0.8 W m⁻¹ K⁻¹ in the 300–650 K range in BiTe resulting from low energy optical phonon branches which originate primarily from the localized vibrations of Bi bilayer. It has high μ≈516 cm² V⁻¹ s⁻¹ and 707 cm² V⁻¹ s⁻¹ along parallel and perpendicular to the spark plasma sintering (SPS) directions, respectively, at room temperature.     

Comparison of optical properties of periodic photonic–plasmonic and randomly textured back reflectors for nc-Si solar cells

Light trapping is essential to harvest long-wavelength red and near-infrared photons in thin film silicon solar cells. Light trapping in p-i-n thin film cells is commonly achieved with back-reflectors, and in n-i-p cells with textured front transparent conductors. We systematically compare the optical properties and performance of randomly roughened back reflectors with periodic plasmonic-photonic back-reflectors in p-i-n solar cells. The randomly textured back reflectors were prepared to have very high diffuse reflectance comparable to the state of the art. The periodic back reflectors of tapered nano-pillars/bumps show enhanced quantum efficiency and optical absorption over randomly structured back reflectors using the same solar cell architecture in nc-Si solar cells. The strong diffraction and light concentration in periodic back reflectors may be more beneficial than the light scattering offered by randomly textured back reflectors.     

Synthesis of 2-(ethynyloxy)naphthaene-1-carbaldehyde using 2-hydroxy benzyl alcohol and propargyl bromide in aqueous micellar media

Research on Chemical Intermediates - A highly convenient method has been developed for the synthesis of 2-(ethynyloxy) napthaene-1-carbaldehyde and its derivatives. Substituted naphthalene...     

Stability aspects of the Hayes delay differential equation with scalable hysteresis

Nonlinear Dynamics - Hysteresis models are strongly nonlinear, with slope discontinuities at every load reversal. Stability analysis of hysteretically damped systems is therefore challenging....     

A glassy carbon electrode modified with SnO2 nanofibers,polyaniline and hemoglobin for improved amperometric sensing of hydrogen peroxide

Microchimica Acta - The authors describe a glassy carbon electrode (GCE) modified with a multiporous nanofibers prepared from SnO2, polyaniline and hemoglobin, and its application to the...