First integrals and Darboux polynomials of natural polynomial Hamiltonian systems

In this Letter we study some aspects of the relationship between the existence of Darboux polynomials and additional polynomial first integrals in natural polynomial Hamiltonian systems with a finite number of degrees of freedom. More precisely, first we improve results of the paper of Maciejewski and Przybylska [A.J. Maciejewski, M. Przybylska, Phys. Lett. A 326 (2004) 219]; and after we answer two open questions presented in that paper.     

On comparing the performance of primary care providers

In the past few years primary health care has been characterised as central to the development of the National Health Service in the United Kingdom. Furthermore, performance assessment is seen as a way of achieving care of high standards. Performance indicators and targets are being developed to assess primary care providers, and to develop financial incentives. However, the number of studies that have compared the performance of primary care providers is limited and the existing approaches to evaluation are open to improvement.     

Formation of 2D spherulites in Langmuir films of amphiphilic T-shaped liquid crystals

Langmuir films of facial T-shaped amphiphilic liquid crystals were studied at the air-water interface. The liquid crystals were composed of three incompatible segments: a central rigid rodlike p-terphenyl (TP) group, two flexible hydrophobic n-alkyl terminal chains of identical length linked through ether bonds, and one hydrophilic lateral chain of three ethylene oxide units with a carboxyl end group. In order to determine the influence of the alkyl chain length on the characteristics of condensed films three TPs having n-alkyl chains with eight (TP8/3), ten (TP10/3) or 16 (TP16/3) carbon atoms were investigated. Surface pressure - mean molecular area isotherms revealed clear differences. TP8/3 and TP10/3 exhibit an extended plateau region where a phase transition from monolayer to multilayer takes place. On the other hand, the TP16/3 isotherm showed a distinct maximum ('spike') corresponding to a surprising surface crystallization process which is reported for the first time for a Langmuir film of a liquid crystal. Brewster angle microscopy clearly confirmed these differences: TP8/3 and TP10/3 formed circular domains with liquid crystalline order, while TP16/3 formed well-defined two-dimensional polycrystalline spherulites which are fractured after further compression. The film thickness determined by X-ray reflectivity measurements correlated with a multilayer formation for TP10/3. The morphology of Langmuir-Blodgett (LB) films transferred onto silicon wafers and studied by atomic force microscopy also confirmed the striking different behavior (multilayer formation vs. 2D crystallization) of the TPs under investigation.     

Oxidative modifications in glycated insulin

At the present, the term “glycoxidation” is recognized as the synergistic interaction between glycation and oxidative processes which, with the help of redox-active metals, consequently leads to the production of deleterious tissue modifications. The association between glycation and oxidation events is considered one of the major factors in the accumulation of non-functional damaged proteins, enhancing the oxidative damage at the cellular level. Because of the central role of insulin in the biology of diabetes, we investigated the site-specific oxidation of native and glycated insulin (mono, di, and tri-glycated forms), through metal-catalyzed oxidation, with a combination of liquid chromatography and mass spectrometry. With this approach we were able to identify the residues that were mainly oxidized, and peptide sequences resulting from oxidative cleavage of insulin. Tyrosine, phenylalanine, and cysteine were the main affected residues. Time-course analysis (0–48 h) of the oxidative damage enabled to detect more pronounced and earlier oxidative modifications in the case of glycated insulin. We also observed more severe oxidative damage as the number of glycation sites increased in insulin. These oxidative modifications included other oxidized residues, namely proline, histidine, valine, leucine, and glycine, which were shown to be carbonylated. In addition, we identified new sites of peptide cleavage with the formation of new fragments, derived mainly from chain B, which were both glycated and oxidatively modified. Peptide fragmentation occurred mainly between the residues phenylalanine, glycine, leucine, and tyrosine. Moreover, for diglycated and triglycated forms we observed further oxidative cleavage occurring in both chains, with oxidation and fragmentation of residues occurring near cysteine bridges, especially in chain A.     

Iron oxide-filled micelles as ligands for fac-[M(CO)3]+ (M = (99m)Tc, Re)

Magnetite-filled micelles capture fac-[M(OH(2))(3)(CO)(3)](+) complexes (M = (99m)Tc, Re), creating versatile self-assembled constructs for multimodal SPECT/MR/optical imaging and radiopharmaceutical guided delivery.     

Investigation of degradation mechanisms by portable Raman spectroscopy and thermodynamic speciation: the wall painting of Santa María de Lemoniz (Basque Country, North of Spain)

To characterise the polymeric properties of processed lignins, a new method has been developed using hydrophobic interaction chromatography (HIC). This method separates the lignin polymers into fractions based on differences in hydrophobicity using low pressure liquid chromatography (LPLC). The hydrophobic column material consists of monodisperse polystyrene/divinylbenzene beads. An elution gradient was prepared monitoring the electrolyte concentration and pH. Citric acid buffer, containing ammonium sulphate that promotes adsorption to the column material, was used as mobile phase in a step-wise gradient together with ethanol (20/80% (v/v) ethanol/water, pH 12) and isopropanol (40/60% (v/v) isopropanol/water, pH 12). Depending on eluent composition, the degree of elution was 94% or higher. With the HIC method developed, lignosulphonates and kraft lignins were separated into seven distinctive peaks according to hydrophobicity.     

Mild Method for Ullmann Reaction of 2‐Chlorobenzoic Acids and Aminothiazoles or Aminobenzothiazoles under Ultrasonic Irradiation

One‐pot syntheses of 5H‐[1,3]thiazolo[2,3‐b]quinazolin‐5‐one, 12H‐[1,3]benzothiazolo[2,3‐b]quinazolin‐12‐one, and corresponding derivatives were developed using the copper‐catalyzed Ullmann condensation. The use of ultrasonic irradiation enhanced yields and reduced the reaction time to minutes.     

Synthesis of 9‐Methyl‐11H‐pyrido[2,1‐b]quinazolin‐11‐one Using the Ullmann Condensation

The Ullmann condensation between 2‐chlorobenzoic acid and 2‐amino‐6‐methyl pyridine in DMF as solvent yielded 2‐[(6‐methyl‐2‐pyridinyl)amino] benzoic acid. The cyclization of this acid gave two isomers, the 9‐methyl‐11H‐pyrido[2,1‐b]quinazolin‐11‐one and, in a minor quantity, 2‐methylbenzo[b][1,8]naphtyridin‐5(10H)‐one. Using ultrasound irradiation the pyridoquinazolin‐11‐one was obtained as the sole product.