Quantization by parts,self-adjoint extensions,and a novel derivation of the Josephson equation in superconductivity

There has been a lot of interest in generalizing orthodox quantum mechanics to include POV measures as observables, namely as unsharp obserrables. Such POV measures are related to symmetric operators. We have argued recently that only maximal symmetric operators should describe observables.¹ This generalization to maximal symmetric operators has many physical applications. One application is in the area of quantization. We shall discuss a scheme, to he called quantization by parts,which can systematically deal with what may be called quantum circuits. As a specific application we shall present a novel derivation of the famous Josephson equation for the supercurrent through a Josephson junction in a superconducting circuit. An interesting effect emerges from our quantization scheme when applied to a superconducting Y-shape circuit configuration. We also propose an experimental test for this effect which is expected to shed light on some conceptual problems on the quantum nature of the condensate.     

Investigation of EDTA anticoagulant in plasma to improve the throughput of liquid chromatography/tandem mass spectrometric assays

In this study, EDTA and heparin are compared as anticoagulants with respect to their efficiency in preventing clot formation in plasma samples that were subsequently analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS). A pilot in vivo pharmacokinetic study for the drug chlorpheniramine was conducted in which both EDTA and heparin plasma samples were collected simultaneously. All conditions except the anticoagulant were held constant during the pharmacokinetic study. Bioanalytical results were compared from samples transferred by manual pipette and by an automated liquid handler workstation. The concentration of chlorpheniramine in samples was determined by LC/MS/MS. Results from the analysis of variances (ANOVA) of log-transformed plasma chlorpheniramine concentrations were used to calculate 90% confidence intervals for the ratio least-squares mean values for anticoagulants and for transfer methods. Analytical concentrations of the drug chlorpheniramine were equivalent in heparin- and EDTA-containing plasma. Results suggest that the failure rate for transfer of EDTA plasma (50 micro L by automated workstation or manually) is less than that for heparinized plasma. As a consequence of these results, the vast majority of plasma samples in our laboratories are now collected in EDTA, which allows for use of automated sample transfer resulting in a three-fold timesaving over manual transfer using a single-channel pipette. The ability to use automation has resulted in improved efficiency and cost savings.     

The alpha-effect in methyl transfers from S-methyldibenzothiophenium fluoroborate to substituted N-methylbenzohydroxamates

Studies of the alpha-effect show increased reactivity of nucleophiles having lone pairs of electrons on atoms neighboring the lone pair involved in reactivity when compared to the basicity of the nucleophiles. Hammett-type plots and Br?nsted-type plots of substituted methylphenyl sulfates vs hydrogen peroxide anions and substituted N-methylbenzohydroxanates (NMBH) with substituted methylarenesulfonates or substituted arenedimethylsulfonium ions have large rho or beta(nuc) values, indicating a putative tightening of the usual S(N)2 transition states (anti-Hammond effect). Electrochemical studies of S(N)2-SET or reactivity indicate that SET character occurs in looser transition states, whereas S(N)2 transition states are associated with greater tightness. The alpha-effects for the series of sulfonium salts in completion reactions for 3-ClNMBH anions and 3-nitrophenolate anions are (log k(alpha)/k(normal)) 1.124 for dimethylphenyl sulfonium, 1.512 for dimethyl-1-naphthyl sulfonium, 1.835 for dimethyl-9-anthracenyl sulfonium, and 1.137 for S-methyldibenzylthiophenium. Correlations of the sizes of alpha-effects with typical SET (or ET) experimental parameters and the inverse dependence of the size of the alpha-effect on electron demand indicate inclusion of SET character in these S(N)2 transition states, vs no (or at least diminished) SET character in normal transition states. This dichotomy of tighter S(N)2 transition states, but looser SET transition states indicated in the alpha-effect, is examined in the present work.     

E ∗-dense E-semigroups

We obtain a covering theorem for E ^?-dense E-semigroups showing that such a semigroup has an E ^?-dense, strongly E ^?-unitary E-semigroup as a cover and describe the structure of the latter semigroups.     

Measurement of trace explosive residues in a surrogate operational environment: implications for tactical use of chemical sensing in C-IED operations

A campaign to measure the amount of trace explosive residues in an operational military environment was conducted on May 27–31, 2007, at the National Training Center at Fort Irwin, CA, USA. The objectives of this campaign were to develop the methods needed to collect and analyze samples from tactical military settings, to use the data obtained to determine what the trace explosive signatures suggest about the potential capabilities of chemical-based means to detect IEDs, and, finally, to present a framework whereby a sound understanding of the signature science can be used to guide development of new sensing technologies and sensor concepts of operation. Through our use of combined background and threat signature data, we have performed statistical analyses to estimate upper limits of notional sensor performance that is limited only by the spatial correlation of the signature chemicals to the threats of interest.     

Review of chemical signature databases

This review assesses the current state of chemical signature databases, the primary characteristics that determine their applicability, characterization of their capability to support spectral identifications, and the target audience to which they are directed. Database file formats, spectrometer operating conditions, and spectral matching tools are found to be primary characteristics that determine the applicability of databases and their ability to support spectral identifications. Chemical signature databases have evolved in two very different directions. One movement offers a single portal for chemical signature determinations by multiple analytical techniques. The other movement is toward highly specialized databases that address narrow scientific disciplines. Both movements are necessary, and serve distinctly different needs in the analytical community.     

Endomorphisms of relatively free algebras with weak exchange properties

The structure of the endomorphism monoid of a stable basis algebra A is described. It is shown to be an abundant monoid; the subsemigroup of endomorphisms of finite rank has a regular semigroup of left quotients.     

Proper Covers for Left Ample Semigroups

A left ample semigroup is a semigroup with a unary operation ⁺ which has a (2,1)-algebra embedding into a symmetric inverse monoid I(X), the operation ⁺ on I(X) being defined by α⁺ = αα^-1. We consider some analogues for left ample semigroups of results on E-unitary covers of inverse semigroups due to McAlister and Reilly. The analogue of an E-unitary cover is a proper cover, and we discuss the construction of proper covers in terms of relational homomorphisms, and of dual prehomomorphisms. We observe that our construction gives an E-dense proper cover for an E-dense left ample semigroup. We also consider proper covers constructed from strict embeddings into factorisable left ample monoids. In contrast to the inverse case, not all proper covers arise in this way. However, in the E-dense case, we characterise those E-dense proper covers which can be constructed from such embeddings.     

The validation of a simple LC/MS/MS method for determining the level of mevalonic acid in human plasma

A simple plasma extraction method coupled with liquid chromatography–tandem mass spectrometry (LC/MS/MS) detection was developed and validated for the analysis of endogenous mevalonic acid (MVA), a biomarker indicative of the rate of cholesterol biosynthesis, in human plasma samples. The analyte was extracted from the plasma matrix using a straightforward liquid–liquid sample preparation procedure. The extract supernatants were evaporated, reconstituted in aqueous solvent and injected into the LC/MS/MS system without further processing. The chromatographic separation was achieved on a reverse‐phase high‐performance liquid chromatography column. The accuracy and precision of the method was determined over the concentration range 0.25–25 ng/mL MVA from human plasma extracts in three validation batch runs. Inter‐assay precision (%CV) and accuracy (%RE) of the quality control samples were ≤7.00% (at lower limit quality control) and ≤6.10%, respectively. The sensitivity and throughput of this assay was significantly improved relative to previously published methods, resulting in smaller sample requirements and shorter analysis time. Assay results from a clinical study following the oral administration of an exploratory statin demonstrate that this procedure could potentially be used in the investigation of therapies associated with hypercholesterolemia. Copyright © 2010 John Wiley & Sons, Ltd.