PAM-microfabricated polyurethane scaffolds: in vivo and in vitro preliminary studies

Polymeric scaffolds were realised with linear degradable PU in the form of square, hexagonal and octagonal grids. They were characterised in terms of their mechanical properties. Analysis shows that the mechanical properties of the scaffolds depend on their geometries which are easily modulated using PAM. In vitro biological assays showed that PU promotes the adhesion and proliferation of fibroblast cells and that cell activities are better on PU scaffolds than on PU films. In vivo implantation of PU and PLGA scaffolds and PU films demonstrated that the scaffolds are completely resorbed after three months with a slight inflammatory response, while the PU film was still present after six months with an intense granulomatous reaction.     

Luminescent Ionic Transition‐Metal Complexes for Light‐Emitting Electrochemical Cells

Higher efficiency in the end‐use of energy requires substantial progress in lighting concepts. All the technologies under development are based on solid‐state electroluminescent materials and belong to the general area of solid‐state lighting (SSL). The two main technologies being developed in SSL are light‐emitting diodes (LEDs) and organic light‐emitting diodes (OLEDs), but in recent years, light‐emitting electrochemical cells (LECs) have emerged as an alternative option. The luminescent materials in LECs are either luminescent polymers together with ionic salts or ionic species, such as ionic transition‐metal complexes (iTMCs). Cyclometalated complexes of Ir^III are by far the most utilized class of iTMCs in LECs. Herein, we show how these complexes can be prepared and discuss their unique electronic, photophysical, and photochemical properties. Finally, the progress in the performance of iTMCs based LECs, in terms of turn‐on time, stability, efficiency, and color is presented.     

Multi-use NBD-based tetra-amino macrocycle: fluorescent probe for metals and anions and live cell marker

Ligand L (4-(7-nitrobenzo[1,2,5]oxadiazole-4-yl)-1,7-dimethyl-1,4,7,10-tetra-azacyclododecane) is a versatile fluorescent sensor useful for Cu(II), Zn(II) and Cd(II) metal detection, as a building block of fluorescent metallo-receptor for halide detection, and as an organelle marker inside live cells. Ligand L undergoes a chelation-enhanced fluorescence (CHEF) effect upon metal coordination in acetonitrile solution. In all three complexes investigated the metal cation is coordinatively unsaturated; thus, it can bind secondary ligands as anionic species. The crystal structure of [ZnLCl](ClO(4)) is discussed. Cu(II) and Zn(II) complexes are quenched upon halide interaction, whereas the [CdL](2+) species behaves as an OFF-ON sensor for halide anions in acetonitrile solution. The mechanism of the fluorescence response in the presence of the anion depends on the nature of the metal ion employed and has been studied by spectroscopic methods, such as NMR spectroscopy, UV/Vis and fluorescence techniques and by computational methods. Subcellular localization experiments performed on HeLa cells show that L mainly localizes in spot-like structures in a polarized portion of the cytosol that is occupied by the Golgi apparatus to give a green fluorescence signal.     

Enhancement of Fatty Acid‐based Polyurethanes Cytocompatibility by Non‐covalent Anchoring of Chondroitin Sulfate

For tissue engineering purpose biopolymer chondroitin sulfate (CS), one of the major components of cartilage and bone extracellular matrix, was immobilized onto the surface of amino‐functionalized polyurethane (PU) films derived from naturally occurring oleic and 10‐undecenoic acids. The amino‐functionalized PUs were prepared by aminolysis with 1,6‐hexamethylenediamine of synthesized PUs containing methyl ester groups. FTIR‐ATR, XPS, SEM, and water contact angle measurements were used to confirm the surface changes at each step of treatment, both in morphologies and chemical composition. Cytotoxicity and cell morphology analysis using osteoblast cell line MG63 showed that PU‐CS films are suitable materials for cell growth, spreading, and differentiation.

     

Characterization of gas phase aggregates of bis(2‐ethylhexyl)sulfosuccinate (AOT) and divalent metal ions. Elimination of radical species in the decomposition pathways of even‐electron [AOTMIICl2]– anions

Structure and properties of even‐electron anionic species formed by bis(2‐ethylhexyl)sulfosuccinate (AOT) and divalent metal ions (M^II) with stoichiometry [AOTM^IICl₂]^– have been investigated by using electrospray ionization and different mass spectrometry techniques, such as high resolution, accurate mass measurements, collision‐induced dissociation (CID) multiple‐stage mass spectrometry. Owing to CID, eliminations of neutrals, mainly consisting in hydrochloric acid, 2‐ethyl‐1‐hexene and 2‐ethylhexanol, and an unexpected loss of an alkyl radical have been observed. The radical anions [C₄HO₆SM^IICl]^–? so produced have been characterized by MS³ experiments. Density functional theory calculations have been carried out for investigating structure and stability of the ionic species formed in the decomposition pathways. Copyright © 2012 John Wiley & Sons, Ltd.     

Powerful approach to heterocyclic skeletal diversity by sequential three-component reaction of amines, isothiocyanates, and 1,2-diaza-1,3-dienes

By highly efficient, one-pot, three-component reactions, combining one set of 1,2-diaza-1,3-dienes (DDs), primary amines, and isothiocyanates in a different sequential order of addition, heterocyclic skeletal diversity can be achieved. The key feature discriminating the different heterocyclic core formation is the availability of the N or S heteronucleophile to give the first Michael addition step affording regioselective substituted 2-thiohydantoins or 2-iminothiazolidinones. The hydrazone or enehydrazino side chain at the 5-position of both heterocycles represents a valuable functionality to reach novel 5-hydroxyethylidene derivatives difficult to obtain by other methods.     

Comparison of noncontact and fiber-based fluorescence-mediated tomography

We present a comparative experimental phantom study of fiber-based and noncontact fluorescence tomography with respect to quantitation and localization of reconstructed fluorescent inclusions in turbid media such as tissue. Noncontact acquisition is usually considered potentially superior to fiber-based techniques because of the availability of a large number of detector readouts through a CCD. Our results indicate, however, that noncontact acquisition itself might improve the quality of reconstructions significantly, even without increasing the number of detectors and thus keeping the inverse problem moderately complex.     

Room-temperature diode-pumped Yb:KYF(4) laser

Continuous-wave laser action has been demonstrated in a diode-pumped Yb:KYF(4) crystal. Crystal growth, spectroscopic measurements, and laser results are presented. A maximum output power of 505 mW, a slope efficiency of 43%, and a continuous wavelength tunability range of 65nm, from 1013 to 1078 nm, have been obtained at room temperature.     

Classical nuclear motion in quantum transport

An ab initio quantum-classical mixed scheme for the time evolution of electrode-device-electrode systems is introduced to study nuclear dynamics in quantum transport. Two model systems are discussed to illustrate the method. Our results provide the first example of current-induced molecular desorption as obtained from a full time-dependent approach and suggest the use of ac biases as a way to tailor electromigration. They also show the importance of nonadiabatic effects for ultrafast phenomena in nanodevices.