Rapid Ti(Oi-Pr)4 facilitated synthesis of α,α,α-trisubstituted primary amines by the addition of Grignard reagents to nitriles under microwave heating conditions

A series of carbinamines (α,α,α-trisubstituted amines) have been prepared in a simple and efficient one-pot procedure by the addition of Grignard reagents to a series of aliphatic, aromatic and heteroaromatic nitriles. The resulting magnesium imines are subsequently converted to the desired amine after treatment with Ti(Oi-Pr)₄ and additional microwave heating. Key to this procedure is the use of microwave heating for both steps of the reaction protocol, which significantly improves both reaction yields and reduces reaction times. In general, the Grignard addition reaction is complete within 5-10 min at 100 °C followed by conversion with Ti(Oi-Pr)₄ and additional microwave heating to give the target amines in good yields.     

Analysis of pharmaceuticals in indirect potable reuse systems using solid-phase extraction and liquid chromatography–tandem mass spectrometry

A solid-phase extraction (SPE) LC–MS/MS method for 18 commercial drugs in secondary wastewater and product water from water recycling plants using microfiltration (MF) and reverse osmosis (RO) has been developed, optimised and validated. The method incorporates a range of multi-class pharmaceuticals including lipid lowering agents, analgesics, antipyretics, non-steroidal anti-inflammatory drugs, antidepressants, anticoagulants, tranquilizers, cytostatic agents, and antiepileptics. Method limits of quantitation (MLQs) in secondary wastewater ranged from 15 to 250 ng/L, while MLQs in post-RO water ranged from 1 to 25 ng/L. Results from analysis of secondary wastewater from Western Australia are presented, and represent the largest survey of non-antibiotic pharmaceuticals within Australia to date. Analysis of post-RO water from two MF/RO water recycling facilities also demonstrate that MF/RO treatment removes most pharmaceuticals to below the analytical limits of detection, and more importantly, up to seven orders of magnitude below health-based guideline values.     

Electroanalytical Determination of Cadmium(II) and Lead(II) Using an Antimony Nanoparticle Modified Boron‐Doped Diamond Electrode

We report the simultaneous electroanalytical determination of Pb²⁺ and Cd²⁺ by linear sweep anodic stripping voltammetry (LSASV) using an antimony nanoparticle modified boron doped diamond (Sb‐BDD) electrode. Sb deposition was performed in situ with the analytes, from a solution of 1 mg L^?1 SbCl₃ in 0.1 M HCl (pH 1). Pb²⁺ inhibited the detection of Cd²⁺ during simultaneous additions at the bare BDD electrode, whereas in the presence of antimony, both peaks were readily discernable and quantifiable over the linear range 50–500 μg L^?1.     

<Emphasis Type="Italic">L</Emphasis><Superscript>2</Superscript>-singular dichotomy for orbital measures of classical simple Lie algebras

We prove that the G-invariant orbital measures supported on adjoint orbits in the Lie algebra of a classical, compact, connected, simple Lie group satisfy a smoothness dichotomy: Either μ ^k is singular to Lebesgue measure or μ ^k ∈ L ². The minimum k for which μ ^k ∈ L ² is specified and is also the minimum k such that the k-fold sum of the orbit has positive measure. S. K. Gupta appreciates the hospitality of the Department of Pure Mathematics at the University of Waterloo where some of this research was done. K. E. Hare was supported in part by NSERC.     

Notes on local o‐minimality

We introduce and study some local versions of o‐minimality, requiring that every definable set decomposes as the union of finitely many isolated points and intervals in a suitable neighbourhood of every point. Motivating examples are the expansions of the ordered reals by sine, cosine and other periodic functions (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Nanoscale metal-organic frameworks as potential multimodal contrast enhancing agents

Nanoscale metal-organic frameworks (NMOFs) based on Gd3+ centers and benzenedicarboxylate and benzenetricarboxylate bridging ligands were synthesized using reverse microemulsions and characterized using SEM, PXRD, and TGA. These NMOFs exhibit extraordinarily large R1 and R2 relaxivities because of the presence of up to tens of millions of Gd3+ centers in each nanoparticle and are thus efficient T1 and T2 contrast agents for MRI. The NMOFs can also be made highly luminescent by doping with Eu3+ or Tb3+ centers. The results from this work suggest that NMOFs can be used as potential contrast agents for multimodal imaging.     

Photofragment coincidence imaging of small I-(H2O)n clusters excited to the charge-transfer-to-solvent state

The photodissociation dynamics of small I-(H2O)n(n=2-5) clusters excited to their charge-transfer-to-solvent (CTTS) states have been studied using photofragment coincidence imaging. Upon excitation to the CTTS state, two photodissociation channels were observed. The major channel (approximately 90%) is a two-body process forming neutral I+(H2O)n photofragments, and the minor channel is a three-body process forming I+(H2O)n-1+H2O fragments. Both processes display translational energy [P(ET)] distributions peaking at ET=0 with little available energy partitioned into translation. Clusters excited to the detachment continuum rather than to the CTTS state display the same two channels with similar P(ET) distributions. The observation of similar P(ET) distributions from the two sets of experiments suggests that in the CTTS experiments, I atom loss occurs after autodetachment of the excited [I(H2O)n-]* cluster or, less probably, that the presence of the excess electron has little effect on the departing I atom.     

Formation of silver nanoparticles at the air-water interface mediated by a monolayer of functionalized hyperbranched molecules

Nanofibrillar micellar structures formed by the amphiphilic hyperbranched molecules within a Langmuir monolayer were utilized as matter for silver nanoparticle formation from the ion-containing water subphase. We observed that silver nanoparticles were formed within the multifunctional amphiphilic hyperbranched molecules. The diameter of nanoparticles varied from 2-4 nm and was controlled by the core dimensions and the interfibrillar free surface area. Furthermore, upon addition of potassium nitrate to the subphase, the Langmuir monolayer templated the nanoparticles' formation along the nanofibrillar structures. The suggested mechanism of nanoparticle formation involves the oxidation of primary amino groups by silver catalysis facilitated by "caging" of silver ions within surface areas dominated by multibranched cores. This system provides an example of a one-step process in which hyperbranched molecules with outer alkyl tails and compressed amine-hydroxyl cores mediated the formation of stable nanoparticles placed along/among/beneath the nanofibrillar micelles.     

Comparison of different pairing fluctuation approaches to BCS-BEC crossover

The subject of BCS-Bose-Einstein condensation (BEC) crossover is particularly exciting because of its realization in ultracold atomic Fermi gases and its possible relevance to high temperature superconductors. In this paper we review the body of theoretical work on this subject, which represents a natural extension of the seminal papers by Leggett and by Nozières and Schmitt-Rink (NSR). The former addressed only the ground state, now known as the “BCS-Leggett” wave-function, and the key contributions of the latter pertain to calculations of the superfluid transition temperature T_c. These two papers have given rise to two main and, importantly, distinct, theoretical schools in the BCS-BEC crossover literature. The first of these extends the BCS-Leggett ground state to finite temperature and the second extends the NSR scheme away from T_c both in the superfluid and normal phases. It is now rather widely accepted that these extensions of NSR produce a different ground state than that first introduced by Leggett. This observation provides a central motivation for the present paper which seeks to clarify the distinctions in the two approaches. Our analysis shows how the NSR-based approach views the bosonic contributions more completely but treats the fermions as “quasi-free”. By contrast, the BCS-Leggett based approach treats the fermionic contributions more completely but treats the bosons as “quasi-free”. In a related fashion, the NSR-based schemes approach the crossover between BCS and BEC by starting from the BEC limit and the BCS-Leggett based scheme approaches this crossover by starting from the BCS limit. Ultimately, one would like to combine these two schemes. There are, however, many difficult problems to surmount in any attempt to bridge the gap in the two theory classes. In this paper we review the strengths and weaknesses of both approaches. The flexibility of the BCS-Leggett based approach and its ease of handling make it widely used in T=0 applications, although the NSR-based schemes tend to be widely used at . To reach a full understanding, it is important in the future to invest effort in investigating in more detail the T=0 aspects of NSR-based theory and at the same time the T≠0 aspects of BCS-Leggett theory.     

Precursor ion scanning for detection and structural characterization of heterogeneous glycopeptide mixtures

The structure of N-linked glycans is determined by a complex, anabolic, intracellular pathway but the exact role of individual glycans is not always clear. Characterization of carbohydrates attached to glycoproteins is essential to aid understanding of this complex area of biology. Specific mass spectral detection of glycopeptides from protein digests may be achieved by on-line HPLC-MS, with selected ion monitoring (SIM) for diagnostic product ions generated by cone voltage fragmentation, or by precursor ion scanning for terminal saccharide product ions, which can yield the same information more rapidly. When glycosylation is heterogeneous, however, these approaches can result in spectra that are complex and poorly resolved. We have developed methodology, based around precursor ion scanning for ions of high m/z, that allows site specific detection and structural characterization of glycans at high sensitivity and resolution. These methods have been developed using the standard glycoprotein, fetuin, and subsequently applied to the analysis of the N-linked glycans attached to the scrapie-associated prion protein, PrP(Sc). These glycans are highly heterogeneous and over 30 structures have been identified and characterized site specifically. Product ion spectra have been obtained on many glycopeptides confirming structure assignments. The glycans are highly fucosylated and carry Lewis X or sialyl Lewis X epitopes and the structures are in-line with previous results.