Cyclisation of Allenylidene Ligands to Indenyl Groups on Ruthenium Clusters

Thermolysis of Ru₃ cluster complexes containing diarylallenylidene and dppm ligands results in phenyl migration from dppm to the allenylidene with concomitant H migration and C–C bond formation reactions to give several complexes each containing a cluster-bound indenyl group. In initially-formed complexes 3 or 6, the diarylindenyl group is attached to the cluster by two localized C=C double bonds of one aryl group and a benzylic interaction of the remaining C=C double bond combined with one carbon of the five-membered ring. Thermal rearrangement of these complexes with concomitant loss of CO gives 4 or 7, respectively, in which the indenyl group is more symmetrically bonded to the cluster by two C=C double bonds from the six-membered ring and an ⁵-interaction from the five-membered ring, both of the indenyl ligand. The X-ray crystal structure determination of Ru₃( ₃-PPhCH₂PPh₂)( ₃-C₉H₅Ph₂)(CO)₅ (4) is reported. A related reaction was found between Ru₃(-H)(-CCCPh₂)(-OH)(CO)₉ and Co₂(CO)₈, which afforded CoRu₃( ₃-C₉H₆Ph) (-CO)₄(CO)₅ (8), also structurally characterized, in which the indenyl group caps the Ru₃ face of a CoRu₃ tetrahedron; unusually, there are four CO groups bridging the three Co–Ru bonds.     

Geometric effects in the excited states of conjugated trienes

The fluorescence spectra and intrinsic lifetimes of two constrained trienes [cholesta-4,6,8(14)-triene and cholesta-5,7,9(11)-triene-3β-01] indicate that the lowest energy singlet—singlet transition of the s-trans,cis,s-trans 4,6,8(14) triene is a weak transition to a ¹A_g-like excited state while the s-cis,trans,s-cis 5,7,9(11) triene has a lowest transition which is strongly allowed to a ¹B_u-like excited state.     

A recoverable enzymatic microgel based on biomolecular recognition

The enzyme beta-galactosidase has been immobilized through incorporation into a selectively soluble microgel, prepared from DNA, biotinylated peptide nucleic acid (PNA), and the protein avidin. The enzyme was conjugated to avidin, allowing it to be integrated directly into the microgel network. Efficient hydrolysis of a small-molecule substrate occurred at 37 degrees , but cooling and centrifuging led to precipitation of the microgels and product separation. The microgels were then reconstituted by adding fresh buffer and shaking. The enzymatic activity was completely recovered through repeated cycles. This method should be generalizable to a wide variety of other enzymes and substrates.     

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.     

Aerobic Oxidation in Nanomicelles of Aryl Alkynes,in Water at Room Temperature

On the basis of the far higher solubility of oxygen gas inside the hydrocarbon core of nanomicelles, metal and peroxide free aerobic oxidation of aryl alkynes to β‐ketosulfones has been achieved in water at room temperature. Many examples are offered that illustrate broad functional group tolerance. The overall process is environmentally friendly, documented by the associated low E Factors.     

On the decompositions of T-quasi-martingales on Riesz spaces

The concept of a quasi-martingale is generalised to the Riesz space setting. Here we show that a quasi-martingale can be decomposed into the sum of a martingale and a quasi-potential. If, in addition, the quasi-martingale and its filtration are right continuous we show that the quasi-martingale can decomposed into the sum of a right continuous martingale and the difference of two positive right continuous potentials. The approach is measure-free and relies entirely on the order structure of Riesz spaces.