Expression of ionotropic glutamate receptors in the retina of the rdta transgenic mouse

Background  

The expression of retinal CaMKII is up-regulated in the retina of the rdta mouse in which rod photoreceptors are genetically ablated. As ionotropic glutamate receptors are known substrates of CAMKII, this study set out to determine if the protein levels of ionotropic glutamate receptors in the rdta mouse retina are also affected.     

Anomalous density variations of the molten chalcogenide system GeAsSe

An experimental method of measuring densities of melts with high vapour pressures is described. This method is based upon the absorption of high-energy gamma rays. The method enables densities to be measured even in the case of melts solidifying (or bulk samples melting) inside a sealed system, as long as certain conditions are satisfied. The results of investigations of some melts of the chalcogenide system GeAsSe are presented.The melts so far investigated show an increase in density at high temperatures which is super-imposed on the thermal expansion. The reason for these irregularities is an increase of the average coordination number caused by a change of the bonding system. The bonding system with one-sided overlapping of (sp^x)-hybrid bonding functions changes at higher temperatures to a system in which pσ-bonding functions are extended on more than one side of the atoms. This change of the bonding system explains the transition of the electrical conductivity of rhese melts at high temperatures from a semiconductor-like to a metallic-like conductivity. Because a pσ-bonding system enables the atoms to have a relatively high mobility the viscosities of these melts are very low at high temperatures and are similar to those of molten metals.     

A three-dimensional study of the glottal jet

This work builds upon the efforts to characterize the three-dimensional features of the glottal jet during vocal fold vibration. The study uses a Stereoscopic Particle Image Velocimetry setup on a self-oscillating physical model of the vocal folds with a uniform vocal tract. Time averages are documented and analyzed within the framework given by observations reported for jets exiting elongated nozzles. Phase averages are locked to the audio signal and used to obtain a volumetric reconstruction of the jet. From this reconstruction, the intra-cycle dynamics of the jet axis switching is disclosed.     

One- and two-electron reduction of triarylborane-based helical donor–acceptor compounds

One-electron chemical reduction of 10-(dimesitylboryl)-N,N-di-p-tolylbenzo[c]phenanthrene-4-amine (3-B(Mes)₂-[4]helix-9-N(p-Tol)₂) 1 and 13-(dimesitylboryl)-N,N-di-p-tolyldibenzo[c,g]phenanthrene-8-amine (3-B(Mes)₂-[5]helix-12-N(p-Tol)₂) 2 gives rise to monoanions with extensive delocalization over the annulated helicene rings and the boron p_z orbital. Two-electron chemical reduction of 1 and 2 produces open-shell biradicaloid dianions with temperature-dependent population of the triplet states due to small singlet-triplet gaps. These results have been confirmed by single-crystal X-ray diffraction, EPR and UV/vis-NIR spectroscopy, and DFT calculations.

Stepwise chemical reduction of D–π–A triarylborane-based helicenes gives the corresponding monoanions and dianions with delocalized unpaired electrons. The structures were confirmed by single crystal X-ray diffraction.     

Growth of polymer–metal nanocomposites by pulsed laser deposition

Complex polymer–metal nanocomposites have a wide range of applications, e.g. as flexible displays and packaging materials. Pulsed laser deposition was applied to form nanostructured materials consisting of metal clusters (Ag, Au, Pd and Cu) embedded in a polymer (polycarbonate, PC) matrix. The size and amount of the metal clusters are controlled by the number of laser pulses hitting the respective targets. For Cu and Pd, smaller clusters and higher cluster densities are obtained as in the cases of Ag and Au due to a stronger reactivity with the polymers and thus a lower diffusivity. Implantation effects, differences in metal diffusivity and reactivity on the polymer surfaces, and the coalescence properties are discussed with respect to the observed microstructures on PC and compared to the metal growth on poly (methyl methacrylate), PMMA.     

Proton NMR spectroscopy and magnetic properties of a solution-stable dicopper(II) complex bearing a single mu-hydroxo bridge

The reaction of copper(II) perchlorate with the macrocyclic ligand [22]py4pz in the presence of base leads to formation of a dinuclear complex [Cu(2)([22]py4pz)(mu-OH)](ClO(4))(3)xH(2)O, in which two copper ions are bridged by a single mu-hydroxo bridge. Each copper ion is further surrounded by four nitrogen atoms of the ligand. The mu-hydroxo bridge mediates a strong antiferromagnetic coupling (2J = -691(35) cm(-1)) between the metal centers, leading to relatively sharp and well-resolved resonances in the (1)H NMR spectrum of the complex in solution. We herein report the crystal structure, the magnetic properties, and the full assignment of the hyperfine-shifted resonances in the NMR spectrum of the complex, as well as the determination of the exchange coupling constant in solution through temperature-dependent NMR studies.     

Control of regioselectivity by the lone substituent through steric and electronic effects in the nitrosoarene ene reaction of deuterium-labeled trisubstituted alkenes

For the ene reaction of 4-nitronitrosobenzene (ArNO) with a variety of primary and secondary lone alkyl-substituted substrates, the twix/twin regioselectivity is constant at about 85:15. In contrast, for the lone tert-butyl group and for lone aryl substituents, the twix regioisomer is obtained exclusively. These regioselectivities have been rationalized in terms of steric interactions and coordination between the enophile and the substrates in the transition states of the first reaction step.     

Review on Standardisation of Methods Characterising the Geometric Structure of Dispersed or Porous Solids

Short survey on the latest developments on standardisation and standard reference materials for particles, surfaces and pore size analysis. This revised version was published online in August 2006 with corrections to the Cover Date.