Preparation of sodium dimolybdate by the pyrolysis of sodium oxomolybdenum (VI) oxalate

Thermal studies on various oxalato complexes have been of immense interest as they yield finely divided, highly reactive oxides which are usually obtained at a much lower temperature than that required in the conventional method of preparation, i.e., heating a mixture of two or more constituents [1]. A survey of the literature reveals that the compounds having the general formula A₂[Mo₂O₅(C₂O₄)₂(H₂O)₂], where A = K⁺, NH⁺₄[2] and A = Cs⁺ [3], have been prepared and their thermal decomposition is studied, but no such information is available regarding the preparation and characterisation of Na₂[Mo₂O₅(C₂O₄)₂(H₂O)₂] (SMO), which forms the subject of study of this paper. Sodium dimolybdate (Na₂Mo₂O₇), the decomposition product of SMO, is obtained at 280°C, a temperature much lower than that required in the conventional method of preparation of heating a mixture of Na₂MoO₄ and MoO₃ [4].     

Thermodynamics and heat transfer study of a circular tube embedded with novel perforated angular-cut alternate segmental baffles

Journal of Thermal Analysis and Calorimetry - Baffles are used for heat transfer enhancement in heat exchanger tubes. However, they also increase the friction factor in the flow channel....     

Development and Validation of Highly Sensitive LC–ESI-MS/MS Method for Bortezomib and Its Applications for Plasma Levels and Drug Content of Branded and Generic Formulations in India

In the present study, a highly sensitive and reproducible bio-analytical method was developed using LC–ESI-MS/MS to assess the lower plasma levels of bortezomib in multiple myeloma patients. The gradient elution was optimized using reverse-phase C18 column with mobile phases consisting of water and acetonitrile in 0.1% formic acid. Multiple reaction monitoring mode was used for quantification using precursor-to-product ion transition for bortezomib and sulfadiamethoxine was used as internal standard. This method was validated with a linearity range of 0.195–25 ng mL^?1. Intra-day and inter-day accuracy was 99.17–101.89% and 95.01–102.92% with precision of?<?9.87% and?<?8.77%, respectively. Bortezomib was stable in plasma samples stored at ? 80 °C for up to 10 months. The lower limit of quantification was found to be 0.195 ng mL^?1. This method was also found to be capable of quantifying bortezomib trough levels (ranging 0.19–0.7 ng mL^?1) in plasma of multiple myeloma patients post-cycle 1–6. Bortezomib content in the commonly prescribed generic formulations was also studied. The concentration in all formulations was within the 90–110% of the innovator, as prescribed by the USFDA, ruling out their role blood level variation. The study supports the use of this method for trough level estimation and therapeutic drug monitoring of bortezomib in multiple myeloma patients.

     

Synthesis, structural characterisation and biological activity of novel N-(ferrocenylmethyl)benzene-carboxamide derivatives

A series of N-(ferrocenylmethyl)benzene-carboxamide derivatives (4a-f) have been synthesised by coupling ferrocenylmethyl amine 3 with benzoic acid and various substituted fluorobenzoic acids using the standard 1,3-dicyclohexylcarbodiimide (DCC), 1-hydroxybenzotriazole (HOBt) protocol. All compounds were fully characterised using a combination of ¹H NMR, ¹³C NMR, ¹⁹F NMR, DEPT-135, ¹H-¹H COSY and ¹H-¹³C COSY (HMQC) spectroscopy and electrospray ionisation mass spectrometry (ESI-MS). The compounds 4a, 4d, 4e and 4f exhibited cytotoxic effects on the MDA-MB-435-S-F breast cancer cell line. Single crystal X-ray crystallographic data for 4d is also presented.     

Structure of spherical electric double layers: a density functional approach

A density functional theory is presented for the structure of spherical electric double layers within the restricted primitive model, where the macroion is considered as a hard sphere having uniform surface charge density, the small ions as charged hard spheres, and the solvent is taken as a dielectric continuum. The theory is partially perturbative as the hard-sphere contribution to the one-particle correlation function is evaluated using suitably averaged weighted density and the ionic part is obtained through a second-order functional Taylor expansion around the uniform fluid. The theory is in quantitative agreement with Monte Carlo simulation for the density profiles and the zeta potentials over a wide range of macroion sizes and electrolyte concentrations. The theory is able to provide interesting insights about the layering and the charge inversion phenomena occurring at the interface.     

Surface modification of poly(dimethylsiloxane) with a perfluorinated alkoxysilane for selectivity toward fluorous tagged peptides

Poly(dimethylsiloxane) (PDMS) and similar polymers have proved to be of widespread interest for use in microfluidic and similar microanalytical devices. Surface modification of PDMS is required to extend the range of applications for devices made of this polymer, however. Here we report on the grafting of perfluorooctyltriethoxysilane via hydrolysis onto an oxidized PDMS substrate in order to form a fluorinated microchannel. Such a fluorinated device could be used for separating fluorous tagged proteins or peptides, similar to that which has been recently demonstrated in a capillary electrophoresis system or in an open tubular capillary column. The modified polymer is characterized using chemical force titrations, contact angle measurements, and X-ray photoelectron spectroscopy (XPS). We also report on a novel means of performing electroosmotic measurements on this material to determine the surface zeta potential. As might be expected, contact angle and chemical force titration measurements indicate the fluorinated surface to be highly hydrophobic. XPS indicates that fluorocarbon groups segregate to the surface of the polymer over a period of days following the initial surface modification, presumably driven by a lower surface free energy. One of the most interesting results is the zeta potential measurements, which show that significant surface charge can be maintained across a wide range of pH on this modified polymer, sufficient to promote electroosmotic flow in a microfluidic chip. Matrix-assisted time-of-flight mass spectrometry (MALDI-TOF MS) measurements show that a fluorous-tagged peptide will selectively adsorb on the fluorinated PDMS in aqueous solution, demonstrating that the fluorinated polymer could be used in devices designed for the enrichment or enhanced detection of fluorous-labeled proteins and peptides.     

A Highly Ultrafine Core–Shell Ir–Cu Bimetallic Nanoparticles and Their Application in Catalytic Oxidation of Textile Dye,Congo Red,by Hexacyanoferrate(III) Ions: A Kinetic Approach

Kinetics and Catalysis - Bimetallic nanoparticles (BMNPs), a pioneer class of material research for catalysis, were intensively explored. We report a versatile catalyst, core–shell...     

Internal Structure Tailoring in 3D Nanoplasmonic Metasurface for Surface-Enhanced Raman Spectroscopy

Tunable nanoplasmonic metasurfaces have resulted in many versatile platforms for sensing applications including surface-enhanced Raman scattering (SERS)-based detection. However, to date, their fabrication still faces challenges in uniformity, repeatability, and controllability. Here, a novel large-area and hierarchical nanoplasmonic array with controlled internal structure and tunable plasmonic properties is reported, relying on controllably tailoring the single nanosphere on a uniform double-layered array into a well-defined nanoflower structure. The fabrication involves colloidal self-assembly, lithography, and plasmonic metal coating. First, a uniformly distributed double-layered colloidal array is fabricated via an ethanol-assisted self-assembly technique. Next, with the help of inductively coupled plasma dry etching, the lower layer is transformed to the nanoflower array with well-defined petal shape. Subsequently, a gold film with controlled thickness is deposited onto the nanoflower structured array, resulting in a tunable optical and SERS-active enhancement effect. Furthermore, 3D finite-difference time-domain simulation shows multiple enhancement sites inside the nanoflower array. Such a brand-new 3D structured array has the potential for varied applications, ranging from SERS sensors to light regulation.     

Crystallization kinetics of compatibilized blends of polypropylene and polyethylenimine

Journal of Thermal Analysis and Calorimetry - In this paper, isothermal and non-isothermal crystallization behaviour of neat polypropylene (PP), blends of PP/maleic anhydride grafted polypropylene...