Aggregation behavior in water of new imidazolium and pyrrolidinium alkycarboxylates protic ionic liquids

A novel class of anionic surfactants was prepared through the neutralization of pyrrolidine or imidazole by alkylcarboxylic acids. The compounds, namely the pyrrolidinium alkylcarboxylates ([Pyrr][CnH2n+1COO]) and imidazolium alkylcarboxylates ([Im][CnH2n+1COO]), were obtained as ionic liquids at room temperature. Their aggregation behavior has been examined as a function of the alkyl chain length (from n = 5 to 8) by surface tensiometry and conductivity. Decreases in the critical micelle concentration (cmc) were obtained, for both studied PIL families, when increasing the anionic alkyl chain length (n). Surprisingly, a large effect of the alkyl chain length was observed on the minimum surface area per surfactant molecule (Amin) and, hence the maximum surface excess concentration (Gmax) when the counterion was the pyrrolidinium cation. This unusual comportment has been interpreted in term of a balance between van der Waals and coulombic interactions. Conductimetric measurements permit determination of the degree of ionization of the micelle (a) and the molar conductivity (?M) of these surfactants as a function of n. The molar conductivities at infinite dilution in water (?8) of the [Pyrr]+ and [Im]+ cations have been then determined by using the classical Kohlraush equation. Observed change in the physicochemical, surface, and micellar properties of these new protonic ionic liquid surfactants can be linked to the nature of the cation. By comparison with classical anionic surfactants having inorganic counterions, pyrrolidinium alkylcarboxylates and imidazolium alkylcarboxylates exhibit a higher ability to aggregate in aqueous solution, demonstrating their potential applicability as surfactant.

The Implications of Bach's Introduction of New Fugal Techniques and Procedures in the Well-Tempered Clavier Book Two

Among the fugues of the WTC II, there are some fugal techniques and procedures that were not explored in the first book. Here, the ‘fugal techniques’ include parallel entries (as used in the fugues in D-sharp minor, G minor and B-flat minor) and double counterpoint at the tenth or twelfth as well as fifteenth (as used in the fugues in G minor and B major). The ‘fugal procedures’, on the other hand, refer to meticulously planned multi-exposition architecture (as seen in the fugues in F-sharp minor exploiting two subsidiary subjects, and B-flat minor exploiting inversion and stretto) and a form in which the appearance of the subsidiary subject is gradually predicted in the fugal discourse (viz. C-sharp minor, G-sharp minor and B major). All these new ideas helped Bach to write more dramatic, more profound fugues for WTC II. The paper will consider how Bach came to acquire the new techniques and to use them in such ways, and what motivated him to adopt these new compositional approaches. Do they offer any clues for our better understanding of why Bach compiled the WTC II?

A study of new photocatalyst indicator inks

This article reports the behaviour of three photocatalyst indicator inks, based on the redox dyes: methylene blue (NIB), resorufin (Rf) and 2,6-dichloroindophenol (DCIP), and assess their performance in comparison to the pioneering resazurin (Rz)-based ink for the rapid assessment of the activity of very thin, photocatalyst films, such as Activ (TM) self-cleaning glass. From a commercial 'demonstrator of photocatalysis' perspective, all three redox dyes appear more attractive compared to Rz since all generate colourless products in the ink formulation when photoreduced on Activ (TM) under anaerobic conditions, whereas, the reduced product from Rz, the redox dye resorufin, Rf. is pink in colour. However, the ink based on Rf is far too slow to effect the rapid measurement of photocatalytic activity even in the absence of oxygen, and in the presence of oxygen the latter inhibits the overall kinetics of photoreduction by re-oxidising the reduced product, dihydroresorufin, HRf, back to Rf. Similarly, despite the attractive rapid rate of photobleaching for NIB under anaerobic conditions, compared to the other redox dyes, the reduced product of the MB-based ink. leuco-MB, is so oxygen-sensitive that the ink cannot be photoreduced under aerobic conditions, thus rendering the ink unsuitable for use in the field. The DCIP-based ink is slightly less easy to photoreduce under both anaerobic and ambient atmospheric conditions compared to the Rz-based ink. However. in addition to its more attractive colour change, the DCIP-based ink is unaffected by the ambient level of oxygen present (%O-2) and the relative humidity (%RH), whereas, for the Rz-based ink, both parameters effect the photoreduction kinetics. By incorporating the DCIP ink into a felt-tipped pen, the ink is suitable for use in the laboratory and field to perform not only a qualitative test, but also to allow a semi-quantitative analysis of photocatalytic activity by eye. (C) 2007 Elsevier B.V. All rights reserved.

COMPARATIVE-STUDY OF NEW AND ESTABLISHED HETEROGENEOUS OXYGEN CATALYSTS

The kinetics of catalysis of a number of new and established heterogeneous O2 catalysts have been studied using Ce(IV) as the oxidant via both the disappearance of the Ce(IV) ions and concomitant appearance of O2. The most active of the catalysts tested utilised a PGM(IV) oxide, usually Ru or Ir, prepared by the Adams method, which appears to generate microcrystalline powders with high surface areas and optimum activities per unit area.

Cloning of new Rhodococcus extradiol dioxygenase genes and study of their distribution in different Rhodococcus strains

Four extradiol dioxygenase genes which encode enzymes active against catechol and substituted catechols were cloned from two different Rhodococcus strains, and their nucleotide sequences were determined. A catechol 2,3-dioxygenase gene (edoC) was shown to be identical to the previously described ipbC gene from the isopropylbenzene operon of Rhodococcus erythropolis. Amino acid sequences deduced from the three other genes (edoA, edoB and edoD) were shown to have various degrees of homology to different extradiol dioxygenases, The EdoA and EdoB dioxygenases were classified as belonging to the third family of type I oxygenases and represented two new subfamilies, whereas the EdoD dioxygenase was a type II enzyme. Analysis of six Rhodococcus strains revealed a wide distribution of the above dioxygenase genes. Rhodococcus sp. I1 was shown to harbour all four of the analysed dioxygenase genes. Nucleotide sequences homologous to the edoB gene were present in all of the strains, including R. erythropolis NCIMB 13065, which did not utilize any of the aromatic compounds analysed. The latter finding points to the existence of a silent pathway(s) for degradation of aromatic compounds in this Rhodococcus strain.

Epigenetics in Vascular Disease - Therapeutic Potential of New Agents

Vascular diseases, including atherosclerosis, angioplasty-induced restenosis, vessel graft arteriosclerosis and hypertension-related stenosis, remain the most prevalent cause of death in the developed world. The aetiology of vascular diseases is multifactorial with both genetic and environmental factors. Recently, some of the most promising research identifies the epigenetic modification of the genome to play a major role in the disease development, linking the environmental insults with gene regulation. In this process, modification of DNA by methylation, and histone modification by acetylation, methylation, phosphorylation and/or SUMOylation are reported. Importantly, recent studies demonstrated that histone deacetylase (HDAC) enzymes are crucial in endothelial integrity, smooth muscle proliferation and in the formation of arteriosclerosis in animal models. The study of HDACs has shown remarkable specificity of HDAC family members in vascular cell growth/death that influences the disease process. Interestingly, the effects of HDACs on arteriosclerosis development in animal models have been observed after HDAC inhibition using specific inhibitors. This provides a new approach for the treatment of vascular disease using the agents that influence the epigenetic process in vascular cells. This review updates the rapid advances in epigenetics of vascular diseases focusing on the role of HDAC family in atherosclerosis. It will also discuss the underlying mechanisms of histone acetylation in vascular cells and highlight the therapeutic potential of such agents.

The effects of new topical treatments on management of glaucoma in Scotland:An examination of ophthalmological health care

Background: The management of glaucoma has been changed in the past decade by the introduction of new drugs. The impact of these changes on clinical care of patients was examined by examining operation and prescribing rates for glaucoma in four geographical areas of Scotland for the years 1994 to 1999. Methods: A retrospective analysis of national health statistics: primary care prescribing data, hospital derived operation rates, consultant numbers, optometrist numbers, and eye test data, expressed by estimated population at risk of glaucoma. The outcome measures were prescribing volume and cost for glaucoma medications, and operation rates, corrected for population estimated to be at risk of glaucoma (PEG), for trabeculectomy, for Scotland as a whole, and for four geographical "regions" (north east, south east, central, and south west Scotland). Results: Prescribed items per 1000 population estimated to have glaucoma (PEG) increased by 24.9% between 1994 and 1999. This was above the general increase in prescribing in Scotland (17.8%). This increase varied in the four health regions evaluated (14.3% to 31.9%). Prescribing of topical ß blockers increased little (6.4%), but there was a large increase in the use of new products (topical prostaglandins, carbonic anhydrase inhibitors, and a agonists), at the expense of miotics (47.7% fall), and older sympathomimetics. This change in prescribing pattern was accompanied by a 61.5% increase in cost (range 42.2% to 73.4% in the four regions). New drugs accounted for more than half of total glaucoma expenditure in 1999. Operation rates (corrected for PEG) fell by 45.9% (range 43.1 to 58.6%) between 1994 and 1999. Other indicators suggested increased activity in ophthalmic areas (for example, cataract operations, eye tests, numbers of optometrists and ophthalmic surgeons all increased). Within north east Scotland operation rates decreased and prescribing increased less than in other regions, both from lowest regional baseline in 1994. Conclusions: The introduction of new drug classes has had dramatic effects on the prescribing of glaucoma treatments. There has been a decline in older treatments and an increase in new agents, which has been associated with a large reduction in operation rates for glaucoma in Scotland over 6 years. Comparison of prescribing and operation data indicates regional differences in healthcare delivery for glaucoma.

Preparation and characterization of new anodes based on Ti mesh for direct methanol fuel cells

A novel anode structure based on Ti mesh for the direct methanol fuel cell (DMFC) has been prepared by thermal deposition of ~5 µm PtRuO2 catalyst layer on ~50 µm Ti mesh. The preparation procedures and the main characteristics of the anode were studied by half-cell testing, scanning electron microscopy analysis, energy-dispersive X-ray measurement, and single-cell testing. The optimum calcination temperature is 450°C, calcination time is 90- 120 min, PtRuO2 catalyst loading is 5.0 mg cm-2, Pt precursor concentration range of solution is 0.14- 0.4 M, and solution aging time is 1 day. The performances of the anodes prepared using the solution kept within 20 days showed no significant difference. When it was used in DMFC feed with low-concentration methanol solution at 90°C, this new anode shows better performance than that of the conventional anode, because its thin hydrophilic structure is a benefit to the transport of methanol and carbon dioxide. However, due to its opening structure, when higher concentration methanol was employed, the performance of the cell with new anode became worse. © 2006 The Electrochemical Society. All rights reserved.

Genetics of New-Onset Diabetes after Transplantation

New-onset diabetes after transplantation is a common complication that reduces recipient survival. Research in renal transplant recipients has suggested that pancreatic ß-cell dysfunction, as opposed to insulin resistance, may be the key pathologic process. In this study, clinical and genetic factors associated with new-onset diabetes after transplantation were identified in a white population. A joint analysis approach, with an initial genome-wide association study in a subset of cases followed by de novo genotyping in the complete case cohort, was implemented to identify single-nucleotide polymorphisms (SNPs) associated with the development of new-onset diabetes after transplantation. Clinical variables associated with the development of diabetes after renal transplantation included older recipient age, female sex, and percentage weight gain within 12 months of transplantation. The genome-wide association study identified 26 SNPs associated with new-onset diabetes after transplantation; this association was validated for eight SNPs (rs10484821, rs7533125, rs2861484, rs11580170, rs2020902, rs1836882, rs198372, and rs4394754) by de novo genotyping. These associations remained significant after multivariate adjustment for clinical variables. Seven of these SNPs are associated with genes implicated in ß-cell apoptosis. These results corroborate recent clinical evidence implicating ß-cell dysfunction in the pathophysiology of new-onset diabetes after transplantation and support the pursuit of therapeutic strategies to protect ß cells in the post-transplant period.