Synthesis and characterization of graphene‐containing thermoresponsive nanocomposite hydrogels of poly(N‐vinylcaprolactam) prepared by frontal polymerization

Thermoresponsive poly(N‐vinylcaprolactam) nanocomposite hydrogels containing graphene were successfully prepared by frontal polymerization. High concentration of graphene (5.0 mg/mL) was obtained by direct graphite sonication in the self‐same liquid monomer, thus avoiding any chemical manipulation and obtaining “real” graphene as nanofiller instead of one of its more or less oxidized derivative, which is what generally reported in published reports. Furthermore, the corresponding nanocomposites were obtained without using any solvent to be eventually removed. The materials were fully characterized by RAMAN, SEM, and TEM, and their swelling behavior and rheological properties were investigated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

A New Easy Access to Enantiomerically Pure 2,2'-Dihydroxy-1,1'-Binaphthyl

Optically pure binaphthyl structures make up the most important family of auxiliaries, ligands and catalysts used in enantioselective reactions. Syntheses of 2,2'-disubstituted-1,1'-binaphtyl derivatives were carried out one pot in water by oxidative coupling with FeCl₃ in the presence of - and -cyclodextrin (CD) derivatives. A new efficient and inexpensive preparation of trihydroxyethyl- and tri-2-hydroxypropyl- - and -CD afforded these powerful solubilizing agents. The resolution of racemic 2,2'-dihydroxy-1,1'-binaphthyl was easily achieved by semipreparative HPLC separating diastereomers obtained from the reaction with (-)menthyl chloroformate. Final basic hydrolysis afforded the enantiomerically pure product.     

Comparison of microbial receptor assay and liquid chromatography for determination of penicillin G and amoxicillin in milk powder

A microbial receptor assay (Charm II Tablet Beta-Lactam Test) and liquid chromatography (LC) were compared for determination of penicillin G (PG) and amoxicillin (AMOX) in reconstituted milk powder. Nonfat dry milk and whole dry milk were reconstituted (10%, w/v) to concentrations of 0, 2.5, 5, 7.5, and 10 ppb PG; nonfat dry milk was reconstituted (10%, w/v) to 0, 7.5, 10, and 15 ppb AMOX. Reconstituted samples were analyzed blindly by each method. Concentrations determined by both methods demonstrated good agreement. A significant difference between methods (p < or = 0.05) was observed only for 7.5 ppb PG in defatted dry milk. Significant differences were not observed between known concentrations and concentrations determined by the Charm II assay for PG or AMOX in defatted dry milk and PG in whole dry milk. Results by LC showed significant differences (p < 0.05) between known and measured concentrations at 10 ppb PG in both milks and 0 ppb AMOX in defatted dry milk. These results suggest that both the microbial receptor assay and LC may be useful for determination of PG and AMOX near safe level and tolerance, respectively, in reconstituted milk powder.     

Carbon and nitrogen distribution in the sediments of lagoon of Ravenna (Italy)

The distribution and the origin of carbon and nitrogen in sediments of an Italian lagoon--located north-east of Ravenna town--were investigated. From 1957 to 1976, the lagoon had been affected by a strong industrial pollution due to an important petrochemical complex. At present, industrial and domestic waste waters undergo a treatment process before being discharged into the lagoon. Sediment samples from 10 locations throughout the lagoon were analysed, in order to document the spatial and vertical distribution of C and N. Data show a very strong variability (organic carbon content varies between 8.9% and 0.14%) and the highest values were found in the immediate vicinity of the industrial discharge. Sediment organic matter shows allochthonous origin in proximity of industrial discharge and autochthonous origin in the remaining areas.     

Ferrocenoyl glycylcystamine: organization into a supramolecular helicate structure

Extensive intermolecular hydrogen bonding in ferrocenoyl glycylcystamine gives rise to a novel ordered double helical arrangement with a helical pitch height of 14 A.     

Optimization of the cyclodextrin-assisted capillary electrophoresis separation of the enantiomers of phenoxyacid herbicides

An ethylcarbonate derivative of beta-cyclodextrin (beta-CD) with three substituents per molecule, hydroxypropyl-beta-CD and native alpha-CD have been tested as resolving agents in the capillary zone electrophoresis (CZE) separation of the four enantiomers of the herbicides mecoprop and dichlorprop. The performances of the three compounds have been quantified by means of two-levels full factorial design and the inclusion constants were calculated from CZE migration time data. Possible structure of inclusion complexes have been proposed, on the basis of molecular mechanics simulations.     

Neural markers of a greater female responsiveness to social stimuli

Background  

There is fMRI evidence that women are neurally predisposed to process infant laughter and crying. Other findings show that women might be more empathic and sensitive than men to emotional facial expressions. However, no gender difference in the brain responses to persons and unanimated scenes has hitherto been demonstrated.