Conversion of unpolarized light to polarized light with greater than 50% efficiency by photorefractive two-beam coupling

All known polarizers operate through a separation of orthogonal electric field components, one of which is subsequently discarded. As a result, 50% of the unpolarized incident light is wasted in the process of conversion to polarized light. We demonstrate a new method by which we use the optical power in the ordinarily discarded component as the pump to amplify the retained component through photorefractive two-beam coupling to achieve greater than 50% throughput.     

Er‐ and Eu‐doped GaP‐oxide porous composites for optoelectronic applications

We demonstrate the controlled preparation of Er‐ and Eu‐doped GaP‐oxide porous composites. The fabrication procedure entails the use of porous semiconductor templates and the impregnation of rare earth ions from a rare earth salt solution in alcohol and thermal treatment. The composites exhibit strong green and red emission that comes from finely dispersed ErPO₄ and EuPO₄ oxide submicron phases in the composite. These materials may prove useful in future generations of optoelectronic and photonic devices. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Room‐Temperature Alkyne–Nitrile Metathesis and Unambiguous Proof for the Existence of a High‐Valent Iron‐Nitrido Dication in the Gas Phase. Short Communication

An unprecedented alkyne–nitrile metathesis takes place when the high‐valent iron‐nitrido dication [Fe(L)N]²⁺, with L=2,6‐bis(2‐methyl‐1,3‐diaminopropan‐2‐yl)pyridine, is reacted with alkynes in the gas phase under thermal conditions. While the detailed role of the alkyne substrate with respect to relative rates, regioselectivities, and branching ratios remains to be elucidated, the very existence of this novel metathesis reaction provides additional experimental evidence of a genuine, long‐lived, formal iron(V)‐nitrido dication.     

Factors affecting the demand for softwood lumber in the united states

This study sets out to examine whether the demand for softwood lumber in the United States is responsive to various market factors including the price of softwood lumber, the price of other building materials, and the level of economic activity (e.g. housing starts). Concern in the analysis is focused on overcoming some of the methodological shortcomings found in previous studies of this issue. The results are conclusive. The quantity of softwood lumber demanded does respond to the various economic factors considered. Moreover, when the structural stability of the estimated relationships is investigated, the results suggest that the demand for softwood lumber regionally in the United States has remained unaltered over the sample period (1950–1985).     

Purification and characterization of recombinant human renin for X-ray crystallization studies

Background  

The renin-angiotensin-aldosterone system (RAS) cascade is a major target for the clinical management of hypertension. Although inhibitors of various components of this cascade have been developed successfully, development of renin inhibitors has proven to be problematic. The development of these inhibitors has been hindered by poor bioavailability and complex synthesis. However, despite the challenges of designing renin inhibitors, the enzyme remains a promising target for the development of novel treatments for hypertension. X-ray crystallographic data could greatly assist the design and development of these inhibitors. Here we describe the purification and characterization of recombinant human renin for x-ray crystallization studies.     

The localized electrons detector as an ab initio representation of molecular structures

The local single particle momentum is proposed as a localized‐electrons detector (LED) that provides a direct three‐dimensional representation of bonding interactions in molecules. It is given exclusively in terms of the electron density and its gradient. We show that the graphical representation of bonding interactions given by LED is consistent with the local curvatures of the electron density as given by the eigenvalues of the Hessian matrix, according to a local symmetry classification of the critical points here introduced. LED consistently complements the topological analysis of the electron density given by the quantum theory of atoms in molecules, by providing a graphical representation of the symmetry of the bonding interactions in molecular systems. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem 110:2418–2425, 2010