Hydrolysis of acetylcholinesterase inhibitors--organophosphorus acid anhydrolase enzyme immobilization on photoluminescent porous silicon platforms

We report on the immobilization of an OPAA enzyme on luminescent porous silicon devices, and on the utilization of this new platform to hydrolyze p-nitrophenyl-soman.     

New identities involving sums of the tails related to real quadratic fields

In previous work, the authors discovered new examples of q-hypergeometric series related to the arithmetic of $\mathbb {Q}(\sqrt{2})$ and $\mathbb{Q}(\sqrt{3})$ . Building on this work, we construct in this paper sum of the tails identities for which some which some of these functions occur as error terms. As an application, we obtain formulas for the generating function of a certain zeta functions for real quadratic fields at negative integers.     

Superconducting proximity effect and majorana fermions at the surface of a topological insulator

We study the proximity effect between an s-wave superconductor and the surface states of a strong topological insulator. The resulting two-dimensional state resembles a spinless px+ipy superconductor, but does not break time reversal symmetry. This state supports Majorana bound states at vortices. We show that linear junctions between superconductors mediated by the topological insulator form a nonchiral one-dimensional wire for Majorana fermions, and that circuits formed from these junctions provide a method for creating, manipulating, and fusing Majorana bound states.     

Development of reference materials for the analysis of acid-extractable metals in sludge

The development of reference materials to verify the determination of metals in sludge is described. Effluents from domestic and industrial treatment facilities were dried, size-reduced and homogenized. Multiple aliquots of each material were analyzed in two different government laboratories to determine reference values for the acid-extractable concentrations of more than 15 metals. These acid-extractable concentrations are distinct from total metal values. Different sample preparation and instrumental methods, along with internal quality assurance protocols, were used to confirm the results. The data show good agreement for most metals in the domestic material. Reference values for the leachable concentrations of several toxic metals and major constituents will become part of the Certificate of Analysis for Standard Reference Material (SRM) 2781 issued by the National Institute of Standards and Technology (NIST). Data for the candidate industrial sludge reference material are also presented and discussed.     

Compensation of self-phase modulation in chirped-pulse amplification laser systems

Small amounts of self-phase modulation can lead to significant pulse distortions in chirped-pulse amplifiers. However, we show the surprising result that the strong chirp of the pulse can be exploited to remove these distortions completely by linear pulse shaping before amplification.     

On lower bounds on the size of sums-of-squares formulas

For sums-of-squares formulas of the form

     

Designing Dimeric Lanthanide(III)-Containing Ionic liquids

Herein, we report on the preparation of liquid dimeric lanthanide(III)-containing compounds. Starting from the design of dimeric solids, we demonstrate that by tuning of anion and cation structures we can lower the melting points below room temperature, whilst maintaining the dimeric structure. Magnetic measurements could establish the spin-spin interactions of the neighboring lanthanide(III) ions in the liquid state at low temperatures, and matched the interactions of the analogous crystalline solid compounds.     

Surface plasmon resonance spectroscopy-based high-throughput screening of ligands for use in affinity and displacement chromatography

We describe an approach that uses surface plasmon resonance (SPR) spectroscopy and self-assembled monolayers (SAMs) for the high-throughput screening of ligands for use in displacement and affinity chromatographic processes. We identified a set of commercially available organic amines and allowed them to react with SAMs presenting interchain carboxylic anhydride groups; the resulting surfaces presented ligands of interest in a background of carboxylic acid groups. We used SPR spectroscopy to determine the extent of adsorption of two model proteinslysozyme and cytochrome conto these "multimodal" surfaces and to select promising "affinity" ligands for further characterization. The attachment of selected ligands to UltraLink Biosupport resulted in beads with a significantly greater affinity for lysozyme than for cytochrome c that would be suitable for use in affinity chromatographic processes. Furthermore, we also used the screens to design "affinity displacers"small molecules that selectively retain lysozyme on chromatographic resins, while displacing cytochrome c. The combination of SPR spectroscopy and SAMs represents a powerful technique for identifying novel ligands that enable the purification of complex protein mixtures.