Influence of glycopolymers structure on the copolymerization reaction and on their binding behavior with lectins

The copolymerization of two glycomonomers bearing lactonolactone and maltonolactone pendant groups with methyl acrylate is here described. The synthesis and characterization of these glycomonomers are fully presented. The analysis of monomer reactivity ratios of both copolymerization systems is performed and compared to those previously obtained for glycomonomers bearing glucosamine and gluconolactone pendant groups. The glass transition temperature is also analyzed as a function of their structure and finally, the molecular recognition behavior is tested against two lectins, Concanavalin A and Ricinus communis Agglutinin.     

Synthesis of a new class of highly fluorescent aryl-vinyl benzo[1,2-b:4,5-b′]difuran derivatives

The synthesis of 2-(2-arylvinyl)- and 2,6-di(2-arylvinyl)dibenzo[1,2-b:4,5-b′]furan derivatives for application in optoelectronics is described. Wittig reaction of the triphenylphosphonium bromides derived from diethyl 2,6-dimethylbenzofuro[5,6-b]furan-3,7-dicarboxylate with aryl aldehydes gave the products in 70-99% yield. The corresponding products derived from furfural and cinnamic aldehyde were also obtained. The prepared products reveal UV-Vis fluorescence with quantum yields, varying from 1% to 100%, and may be used as organic small molecule materials for organic light-emitting devices (OLED).     

Functional micropatterned surfaces prepared by simultaneous UV‐lithography and surface segregation of fluorinated copolymers

A new procedure focused on the design and preparation of structured and functional polymer surfaces by combination of two approaches acting simultaneously is developed. The elaboration of micrometer size patterned surfaces by UV‐light lithography is reported where, in addition, the surface chemical composition can be controlled by surface segregation of a fluorinated copolymer incorporated in the photopolymerizable mixture. As evidenced by contact angle and XPS measurements, the surface composition can be modified depending on such factors as with the environmental conditions or the concentration of copolymer in the blend. Moreover, the functionality of the copolymer is enhanced by the surface pattern created. As a consequence, the wettability of the films can be modified depending on the pattern and composition of the blend. By using this methodology, functional adaptive sensitive surfaces with a well‐defined topography will be obtained in one single step and without the use of tedious and time‐consuming multistep procedures. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Quantitative Determination of Propranolol in Human Serum by High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatography (HPTLC) method for the quantification of propranolol in human serum is developed and...     

Derivatives of benzo[b]furan. Part I. Conformational studies of khellinone and visnaginone

Structural Chemistry - The structural analysis of khellinone and visnaginone indicated the planarity of the benzo[b]furan ring system. The oxygen or carbon atoms of the substituents, –OH,...     

Shallow-underground accelerator sites for nuclear astrophysics: Is the background low enough?

In order to reliably estimate the rate of a charged particle induced nuclear reaction in a non-explosive astrophysical scenario, its cross-section must be measured far below the Coulomb barrier. However, at the corresponding energies the cross-section values are very low, so that the experimental counting rate is dominated by cosmic-ray induced background, even if a suitable anticoincidence shield is applied. This problem can be overcome by performing an accelerator-based experiment in a deep underground site, as has been done with great success at the LUNA 0.4MV accelerator in Gran Sasso, Italy. Several underground accelerators with higher beam energy are in the planning phase worldwide. All of them are shielded by over 1000m of rock, a depth at which cosmic-ray effects are negligible for the purposes of nuclear astrophysics experiments. It is shown here that a combined approach, using a shallow-underground laboratory below 47m of rock and an active shield to veto surviving muons in simple detectors, results in a background level that is not far from that of deep underground sites. Data have been obtained using two ??traveling?? ??-detectors. They have been transported both shallow underground, to the Dresden Felsenkeller in Germany, and deep underground, to the Gran Sasso laboratory in Italy. As shallow-underground facilities are more easily accessible than deep-underground ones, the present finding holds the promise of greatly accelerated progress in the field of cross-section measurements for nuclear astrophysics.     

Formation of one dimensional linear chains by Ir-Ir bonds in cis-dicarbonyldichloroiridate (I)

The particular electronic properties of K[IrCl₂(CO)₂]H₂O are related to its supramolecular structure. Despite the lack of a single-crystal X-ray structure, by means of a variety of powerful experimental and theoretical techniques such as IR, NMR, ESI-MS, EXAFS, DFT calculations and MGAC/CPMD predictions, we obtained geometrical parameters showing the formation of one dimensional linear chains of Ir-Ir with at least 12 Ir atoms. The Ir-Ir distance is 2.82 ± 0.01 Å, which is short enough to assume a metal-metal bond. Restricted optimization of smaller oligomers shows a twist angle of about 51°, suggesting that the monomers are placed parallel to one another in a helical arrangement that make a 360° turn after 8 units.