Polymer mediated peptide immobilization onto amino-containing N-isopropylacrylamide-styrene core-shell particles

Monodisperse cationic core-shell latex particles have been prepared using a shot polymerization process, with N-(3-aminopropyl)-methacrylamide-hydrochloride (APMH) as the functional monomer. The final latexes were characterized with respect to final polymerization conversion, water soluble polymer formation, particle size and size distribution, surface charge density and electrokinetic properties. Then the covalent grafting of maleic anhydride-alt-methyl vinyl ether (MAMVE) copolymer onto aminated latex particles was investigated. The most efficient conditions to obtain derivatised particles with no alteration of the colloidal stability were to control both polymer amount/latex particles concentration ratio and the mixing method of the two species. The charge inversion of the hydrolysed MAMVE functionalized particles was demonstrated by measuring the electrophoretic mobility as a function of pH. Finally, the covalent binding approach was implemented with peptide-MAMVE conjugates, confirming the great potential of this promising methodology for the preparation of reactive latex particles bearing peptides.     

Electrical properties of CuTlSe2 in the liquid state

The electrical conductivity and thermoelectric power of CuTlSe₂ have been investigated as a function of temperature up to 230 °C above its melting point. In the liquid state the experimental data are analyzed in terms of a model developed for the density of states and electrical transport in solid amorphous semiconductors (Mott, 1970). Positive thermoelectric power suggests a large predominance of holes in electrical conduction. It appears that the conduction is due to holes in extended states near the band edge. It is found that the energy gap has a large temperature coefficient =5.5×10^–4eV/K.     

Dielectric relaxation and AC conduction of an AgTlSe2 semiconductor in the solid and liquid states

Measurements of the dielectric properties of AgTlSe₂ in the solid and liquid states were carried out in a wide range of frequencies and temperatures. The material displayed dielectric dispersion, and a loss peak was observed. Cole-Cole diagrams have been used to determine the distribution parameter (a) and the molecular relaxation time (). The process of dielectric relaxation (loss) and ac conduction was attributed to the correlated barrier hopping model suggested by Elliott for amorphous solids, where two carriers simultaneously hop over a barrier between charged defectD ⁺ andD ^– states.     

Recent advances in solid-state beyond lithium batteries

Journal of Solid State Electrochemistry - As battery technologies are in continuous development, and especially due to the rapid growth in vehicle electrification, which requires large (e.g.,...     

New palladium catalyst immobilized on epoxy resin: synthesis,characterization and catalytic activity

A new thiol‐functionalized epoxy resin as a support for palladium(II) complexes has been synthesized in good yields. A palladium catalyst was ‘heterogenized’ by anchoring [PdCl₂(PhCN)₂] complexes to these thiol‐functionalized polymers via ligand exchange reaction. These new palladium catalysts were tested in Mizoroki–Heck coupling and hydrogenation reactions. The activity of the complexes in terms of yield is comparable to that of homogeneous PdCl₂(PhCN)₂. The stability and a good recycling efficiency of these catalysts make them useful for prolonged use. The constant and good selectivity of the supported catalysts during recycling experiments indicate that they could be useful for practical application in many organic reactions. To characterize the heterogeneous complexes before and after use, X‐ray photoelectron spectroscopy, infrared spectroscopy, scanning electron microscopy, energy dispersive X‐ray microscopy, atomic absorption spectroscopy and time‐of‐flight secondary ion mass spectrometry were applied. Density functional theory calculations were also used to better understand the structures of the obtained palladium complexes. Polythiourethanes contain three atoms, oxygen, nitrogen and sulfur, capable of coordinating to transition metals. We examined the possibility of intra‐ and intermolecular binding for both cis and trans palladium complexes. Copyright © 2015 John Wiley & Sons, Ltd.     

Enantioselective route to ferrugine and its methyl analogue via aldol deoxygenation

A simple enantioselective approach to ferrugine (2α-benzoyltropane) and its methyl analogue (2-acetyltropane) is reported. The four-step sequence uses an enantioselective aldol reaction of tropinone with benzaldehyde or acetaldehyde, combined with an aldol deoxygenation via tosylhydrazone reduction and oxidation of the side-chain hydroxy group. The final products, ferrugine and its methyl analogue, are prepared in 35% and 23% overall yields, respectively. Both enantiomers of the products (ee 90-99%) are accessible via the same route using either enantiomer of N,N-bis(1-phenylethyl)amine hydrochloride as the chiral reagent.     

Atom‐Transfer Radical Addition Reactions Catalyzed by RuCp* Complexes: A Mechanistic Study

Kinetic and spectroscopic analyses were performed to gain information about the mechanism of atom‐transfer radical reactions catalyzed by the complexes [RuCl₂Cp*(PPh₃)] and [RuClCp*(PPh₃)₂] (Cp*=pentamethylcyclopentadienyl), in the presence and in the absence of the reducing agent magnesium. The reactions of styrene with ethyl trichloroacetate, ethyl dichloroacetate, or dichloroacetonitrile were used as test reactions. The results show that for substrates with high intrinsic reactivity, such as ethyl trichloroacetate, the oxidation state of the catalyst in the resting state is +3, and that the reaction is zero‐order with respect to the halogenated compound. Furthermore, the kinetic data suggest that the metal catalyst is not directly involved in the rate‐limiting step of the reaction.     

Dynamic nuclear polarization enhancement of protons and vanadium‐51 in the presence of pH‐dependent vanadyl radicals

We report applications of dynamic nuclear polarization to enhance proton and vanadium‐51 polarization of vanadyl sulfate samples doped with TOTAPOL under magic angle spinning conditions. The electron paramagnetic resonance response stemming from the paramagnetic ⁵¹V species was monitored as a function of pH, which can be adjusted to improve the enhancement of the proton polarization. By means of cross‐polarization from the proton bath, ⁵¹V spins could be hyperpolarized. Enhancement factors, build‐up times, and longitudinal relaxation times T₁(¹H) and T₁(⁵¹V) were investigated as a function of pH. Copyright © 2014 John Wiley & Sons, Ltd.     

Preformulation study of nicergoline solid dispersions

Nicergoline, a semisynthetic ergot derivative, which, in its crystalline state, is insoluble in water, was dispersed in polyvinylpyrrolidone K30 (PVP K30) to improve drug particle dissolution. Preformulation studies were carried out initially by differential scanning calorimetry and X-ray powder diffraction in order to predict the conditions and the possibility to actually obtain solid dispersions by mixing the two components at different proportions. Solid dispersions were finally prepared by dissolving nicergoline and PVP K30 in chloroform that was next evaporated under reduced pressure. Under these conditions, an amorphous powder was recovered in every proportion of the two components. Nicergoline demonstrated to be physically and chemically stable for 1 year. The dissolution studies revealed a very high dissolution rate of nicergoline from solid dispersions only lower than the pure amorphous form. This is the consequence of the molecular dispersion of nicergoline in the polymer that enhances the rate of drug release from the polymer.     

The Effect of Fermentation with Kefir Grains on the Physicochemical and Antioxidant Properties of Beverages from Blue Lupin (Lupinus angustifolius L.) Seeds

Plant derived fermented beverages have recently gained consumers’ interest, particularly due to their intrinsic functional properties and presence of beneficial microorganisms. Three variants containing 5%, 10%, and 15% (w/w) of sweet blue lupin (Lupinus angustifolius L. cv. “Boregine”) seeds were inoculated with kefir grains and incubated at 25 °C for 24 h. After processing, beverages were stored in refrigerated conditions (6 °C) for 21 days. Changes in microbial population, pH, bioactive compounds (polyphenolics, flavonoids, ascorbic acid), reducing sugars, and free amino acids were estimated. Additionally, viscosity, firmness, color, and free radicals scavenging properties were determined. Results showed that lactic acid bacteria as well as yeast were capable of growing well in the lupin matrix without any supplementation. During the process of refrigeration, the viability of the microorganisms was over the recommended minimum level for kefir products. Hydrolysis of polysaccharides as well as increase of free amino acids was observed. As a result of fermentation, the beverages showed excellent DPPH, ABTS^+·, ^·OH, and O₂⁻ radicals scavenging activities with a potential when considering diseases associated with oxidative stress. This beverages could be used as a new, non-dairy vehicle for beneficial microflora consumption, especially by vegans and lactose-intolerant consumers.