HPLC–MS Profiling and Structural Identification of [14C]-Diclofenac Metabolites in Mouse Bile

Biliary metabolites present at 6 h post-dose following a single oral dose of [¹⁴C]-diclofenac (10 mg kg^?1) to male bile duct-cannulated C57BL/6 J mice were profiled and identified. Over the 6 h duration of the study ~19.5 % of the administered radioactivity was excreted into the bile as either [¹⁴C]-diclofenac or metabolites. When profiled using HPLC with online radiodetection, the presence of at least 13 radiolabelled components was indicated. These compounds were shown, by consecutive reaction mass spectrometry, to comprise a range of hydroxylated metabolites conjugated to either taurine, glucose and/or glucuronic acid. Both phenolic and acylglucuronide-containing metabolites were observed. The confirmation of the presence of these glucuronide conjugates in mouse bile may have important consequences in the light of emerging theories concerning the role of bacterial glucuronidases for the GI-tract toxicity of NSAIDs such as diclofenac.     

Condensation on ultrahydrophobic surfaces and its effect on droplet mobility: ultrahydrophobic surfaces are not always water repellant

The condensation of water was studied on topography-based ultrahydrophobic surfaces containing hydrophobized silicon pillars. Optical microscopy showed that water nucleated and grew both on top of and between the pillars. As condensation progressed, water between the pillars became unstable and was forced upward to the surface. Macroscopic water droplets on top of the pillars coalesced with condensed water that remained between the pillars, pinning the droplets at their three-phase contact line. Dynamic contact angle measurements on ultrahydrophobic surfaces wet with condensation revealed a dramatic increase in hysteresis compared to that on dry surfaces, leading to a corresponding decrease in water drop mobility.     

Nylon surface modification: 2. Nylon-supported composite films

We have developed techniques for the introduction of reactive functional groups to nylon surfaces via site-specific reactions targeting at the naturally abundant amide repeating units on the surface. In this report, we describe the fabrication of nylon-supported composite surfaces using the most efficient modification methods we have developed. N-Alkylation with (3-glycidoxypropyl)triethoxysilane (GPTES) in the presence of potassium tert-butoxide (t-BuOK) leads to surfaces with silica-like reactivity. Subsequent chemical vapor deposition using tetrachlorosilane (SiCl4) and water results in composite films with a thin layer of silica, which was made hydrophobic by reaction with a fluorinated silane reagent. Reduction of the amide groups with borane-THF (BH3-THF) complex leads to a 69% conversion of surface amides to the corresponding secondary amine groups. Alginate was chosen as the model polyelectrolyte for the introduction of a hydrated surface layer. Because of the strong electrostatic interaction between alginate and the amine-enriched nylon surfaces, the adsorption is fast and concentration-independent (within the concentration range studied). The polysaccharide coats the surface homogeneously, without the formation of large aggregates. The amine surfaces obtained by reduction with BH3-THF ((BH3-THF)nylon-NH) and by alkylation with 2-bromoethylamine hydrobromide (BEA-HBr, (EBA-HBr)nylon-NH2) were also used to study gold deposition through electroless plating. Immobilization of a negatively charged metal complex (AuCl4(-)) was achieved through electrostatic interaction. Gold particles disperse preferentially in the bulk of (EBA-HBr)nylon-NH2 films, while they remain confined to the outer surface layer of (BH3-THF)nylon-NH films.     

From Waste to Green Applications: The Use of Recovered Gold and Palladium in Catalysis

The direct use in catalysis of precious metal recovery products from industrial and consumer waste is a very promising recent area of investigation. It represents a more sustainable, environmentally benign, and profitable way of managing the low abundance of precious metals, as well as encouraging new ways of exploiting their catalytic properties. This review demonstrates the feasibility and sustainability of this innovative approach, inspired by circular economy models, and aims to stimulate further research and industrial processes based on the valorisation of secondary resources of these raw materials. The overview of the use of recovered gold and palladium in catalytic processes will be complemented by critical appraisal of the recovery and reuse approaches that have been proposed.     

Broad‐Band Time‐Resolved Near Infrared Spectroscopy in the TJ‐II Stellarator

First experimental results on broad‐band, time‐resolved Near Infrared (NIR;here loosely defined as covering from 750 to 1650 nm) passive spectroscopy using a high sensitivity InGaAs detector are reported for the TJ‐II Stellarator. Experimental set‐up is described together with its main characteristics, the most remarkable ones being its enhanced NIR response, broadband spectrum acquisition in a single shot, and time‐resolved measurements with up to 1.8 kHz spectral rate. Prospects for future work and more extended physics studies in this newly open spectral region in TJ‐II are discussed. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Carbon chains and rings in the laboratory and in space

Seventy-seven reactive organic molecules of astrophysical interest have been identified in a supersonic molecular beam, 73 in the radio band by Fourier-transform microwave spectroscopy, four in the optical by laser cavity ringdown spectroscopy. Most are linear carbon chains, but six consist of carbon chains attached to the compact, highly polar C3 ring, and two are rhomboidal cyclic configurations of SiC3. The laboratory astrophysics of the radio molecules is complete for the time being, in the sense that essentially all the rotational transitions of current interest to radio astronomy (including hyperfine structure when present) can now be calculated to a small fraction of 1 km s(-1) in equivalent radial velocity; six of the radio molecules have already been detected in space on the basis of the present data. The FTM spectrometer employed in this work is far from fundamental limits of sensitivity, so many more molecules can probably be found by refinements of present techniques. The density of reactive molecules in our supersonic beam is generally high by the standards of laser spectroscopy, and many of the radio molecules probably have detectable optical transitions which we are attempting to find, largely motivated by the long-standing problem of the diffuse interstellar bands. Our most interesting result to date is the detection of a fairly strong molecular band at 443 nm in a benzene discharge, in exact coincidence with the strongest and best known interstellar band. Isotopic shifts measured with partially and totally deuterated benzene suggest that the carrier of the laboratory band is a hydrocarbon molecule with the elemental formula CnH5, with n most likely in the range 3-6.     

Local switching of chemical patterns through light-triggered unfolding of creased hydrogel surfaces

Visible light induces switching of surface chemical patterns based on hybrid gels of thermally responsive poly(N-isopropyl acrylamide) copolymer networks containing iron oxide nanoparticles. The swelling of these hybrid gels is reduced upon illumination (see picture), allowing controlled unfolding of creased features formed owing to an elastic surface instability.     

On fundamental groups of quotient spaces

In classical covering space theory, a covering map induces an injection of fundamental groups. This paper reveals a dual property for certain quotient maps having connected fibers, with applications to orbit spaces of vector fields and leaf spaces in general.