Use of miniaturised isotachophoresis on a planar polymer chip to analyse transition metal ions in solutions from metal processing plants

An electrolyte system, using malic acid as a complexing agent, has been developed to allow the determination of transition metal cations using miniaturised isotachophoresis. The method allowed the simultaneous determination of Mn2+, Cr3+, Fe2+, Co2+, Zn2+ and Ni2+ to be made without interference from other common ions. Limits of detection were calculated to be in the range 0.5-1.0mg l(-1) for Mn2+, Cr3+ Co2+ and Zn2+ and 2.0 mg l(-1) for Fe2+ and 4.7 mg l(-1) for Ni2+. The successful analysis of five industrial samples, containing a range of these metal ions, obtained from metal processing plants were achieved in under 13 min. The separations were performed on a poly(methyl methacrylate) chip with integrated platinum wire conductivity detection electrodes.     

Application of microchip assay system for the measurement of C-reactive protein in human saliva

In the last decade, saliva has been advocated as a non-invasive alternative to blood as a diagnostic fluid. However, use of saliva has been hindered by the inadequate sensitivity of current methods to detect the lower salivary concentrations of many constituents compared to serum. Furthermore, developments in the areas related to lab-on-a-chip systems for saliva-based point of care diagnostics are complicated by the high viscosity and heterogeneous properties associated with this diagnostic fluid. The biomarker C-reactive protein (CRP) is an acute phase reactant and a well-accepted indicator of inflammation. Numerous clinical studies have established elevated serum CRP as a strong, independent risk factor for the development of cardiovascular disease (CVD). CVD has also been associated with oral infections (i.e. periodontal diseases) and there is evidence that systemic CRP may be a link between the two. Clinical measurements of CRP in serum are currently performed with "high sensitivity" CRP (hsCRP) enzyme-linked immunosorbent assay (ELISA) tests that lack the sensitivity for the detection of this important biomarker in saliva. Because measurement of salivary CRP may represent a novel approach for diagnosing and monitoring chronic inflammatory disease, including CVD and periodontal diseases, the objective of this study was to apply an ultra-sensitive microchip assay system for the measurement of CRP in human saliva. Here, we describe this novel lab-on-a-chip system in its first application for the measurement of CRP in saliva and demonstrate its advantages over the traditional ELISA method. The increased sensitivity of the microchip system (10 pg ml(-1) of CRP with 1000-fold dilution of saliva sample) is attributed to its inherent increased signal to noise ratio, resulting from the higher bead surface area available for antigen/antibody interactions and the high stringency washes associated with this approach. Finally, the microchip assay system was utilized in this study to provide direct experimental evidence that chronic periodontal disease may be associated with higher levels of salivary CRP.     

On the nonintegrability of equations for long- and short-wave interactions

We examine the integrability of two models used for the interaction of long and short waves in dispersive media. One is more classical but arguably cannot be derived from the underlying water wave equations, while the other one was recently derived. We use the method of Zakharov and Schulman to attempt to construct conserved quantities for these systems at different orders in the magnitude of the solutions. The coupled KdV–NLS model is shown to be nonintegrable, due to the presence of fourth-order resonances. A coupled real KdV–complex KdV system is shown to suffer the same fate, except for three special choices of the coefficients, where higher-order calculations or a different approach are necessary to conclude integrability or the absence thereof.     

AN EQUILIBRIUM BETWEEN SPIROPHOSPHORANIC AND TETRACOORDINATED PHOSPHORUS COMPOUNDS HAVING THE PHOSPHORUS-BORON BOND

Abstract

A new adduct was isolated from the reaction of borane-dimethyl-sulfide complex and conjugate bases of spirophosphorane prepared from benzilic acid. In solution, it exists as equilibrium between a spirophosphorane and a tetracoordinated phosphorus compound bearing a phosphorus-boron bond.     

SYNTHESIS OF NEW PHOSPHONATED MONOMERS

Two phosphonated methacrylates containing urethane group were synthesized by reacting the isocyanatoethyl methacrylate (IEM; CH ₂ ═C(CH ₃ )COO(CH ₂ ) ₂ NCO) and a phosphonated alcohol (OH(CH ₂ ) _x P(O)(OMe) ₂ , x = 1 or 2), and they are hydrolyzed into mono- and diacid monomers. All these products were characterized in ¹ H and ³¹ P NMR. Unlike usual methods (esterification and transesterification), these syntheses were quantitative and easy to realize.     

Synthesis and liquid crystalline structures of poly(L-lysine) containing undecanamidobiphenyl units in the side chains

In order to obtain liquid crystalline comb-like poly(L-lysine) bearing biphenylyl mesogenic groups in their side chains, we synthesized the 11-(biphenyl-4-carboxamido)undecanamidoL-lysine (KC10φφ) from L-lysine by a five step procedure and transformed the KC10 φφ into its polymerizable cyclic derivative (the N-carboxyanhydride or NCA derivative) by the action of diphosgene. We homopolymerized the NCA of KC10 φφ to obtain the polymer pKC10 φφ and copolymerized it with the NCA of trifluoroacetyl-L-lysine (Kt) to obtain block copolymers pKt-pKC10 φφ of various compositions. X-ray diffraction studies demonstrated the existence of mesophases for our homopolymers and copolymers, resolved the structure of the mesophases and established the influence of temperature and the composition of the copolymers on the structure of the mesophases. Homopolymers pKC10 φφ exhibit, as a function of temperature, three phases (CrE_d, SmB_d and SmA_d) deriving from the β -pleated sheet structure of polypeptides and proteins. The presence of a pKt block in copolymers pKt-pKC10 φφ transforms the smectic CrE_d structure into a SmA_d structure and, when the content of pKt block increases, into a bidimensional hexagonal structure similar to that of the homopolymers pKt.