Azaarene cis-dihydrodiol-derived 2,2 '-bipyridine ligands for asymmetric allylic oxidation and cyclopropanation

Biphenyl dioxygenase-catalysed cis-dihydroxylation of 2-chloroquinoline, 2-chloro-3-methylquinoline and 2-chloro-6-phenylpyridine substrates yielded the corresponding enantiopure cis-dihydrodiols; enantiopure 2,2'-bipyridines, synthesised in four steps from 2-chloroquinoline, proved to be efficient chiral ligands in catalytic asymmetric allylic oxidation and cyclopropanation reactions of alkenes.

Dramatic solvent effects on ring-opening metathesis polymerization of cycloalkenes

A series of metathesis polymers and copolymers have been formed and their structures were analysed by C-13 NMR spectroscopy. Noble metal and non-noble metal salt catalysts are distinguished by their behaviour in various solvents. Thus, in phenolic solvents, the former class produce alternating copolymers from cyclopentene and norbornene, while the latter are unaffected and produce random copolymers. In contrast, ether solvents have the effect of markedly increasing the cis content of polymers from the latter catalysts while the former are unaffected.

Characteristics of RuCl2(CHPh)(PCy3)(2) as a catalyst for ring-opening metathesis polymerization

Ring-opened metathesis polymers and copolymers have been formed from norbornene, norbornadiene, a range of their derivatives, and cyclopentene using RuCl2(CHPh)(PCy3)(2), as catalyst. C-13 NMR analysis of the polymers illustrate a rather selective propagation reaction. The catalyst is highly regioselective, and the polymers are generally high trans with a strong isotactic bias. However, polymers from diene monomers tend to be less isotactic than those from the corresponding monoenes, and in the case of 7-methylnorbornadiene the polymer has an overall syndiotactic bias. A rate enhancing effect, noted previously, due to an oxygen atom proximate to the monomer double bond, is less pronounced than with other initiators. Catalyst activity, in the case of certain diene monomers, was shown to be monomer dependent and rate enhancements were also achieved using phenol as solvent. The results are interpreted in terms of the steric and electronic properties of both the catalyst and the monomers.

Assisted Diagnosis of Cervical Intraepithelial Neoplasia (CIN)

This paper introduces an automated computer- assisted system for the diagnosis of cervical intraepithelial neoplasia (CIN) using ultra-large cervical histological digital slides. The system contains two parts: the segmentation of squamous epithelium and the diagnosis of CIN. For the segmentation, to reduce processing time, a multiresolution method is developed. The squamous epithelium layer is first segmented at a low (2X) resolution. The boundaries are further fine tuned at a higher (20X) resolution. The block-based segmentation method uses robust texture feature vectors in combination with support vector machines (SVMs) to perform classification. Medical rules are finally applied. In testing, segmentation using 31 digital slides achieves 94.25% accuracy. For the diagnosis of CIN, changes in nuclei structure and morphology along lines perpendicular to the main axis of the squamous epithelium are quantified and classified. Using multi-category SVM, perpendicular lines are classified into Normal, CIN I, CIN II, and CIN III. The robustness of the system in term of regional diagnosis is measured against pathologists' diagnoses and inter-observer variability between two pathologists is considered. Initial results suggest that the system has potential as a tool both to assist in pathologists' diagnoses, and in training.

Regioselectivity and stereoselectivity of dioxygenase catalysed cis-dihydroxylation of mono- and tri-cyclic azaarene substrates

cis-Dihydrodiol metabolites were obtained from dioxygenase-catalysed asymmetric dihydroxylations of. five monocyclic (azabiphenyl) and four tricyclic (azaphenanthrene) azaarene substrates. Enantiopurity values and absolute configuration assignments were determined using a combination of stereochemical correlation, X-ray crystallography and spectroscopy methods. The degree of regioselectivity found during cis-dihydroxylation of monocyclic azaarenes (2,3 bond >> 3,4 bond) and of tricyclic azaarenes (bay region > non-bay region bonds) was dependent on the type of dioxygenase used. The cis-dihydrodiol metabolite from an azaarene (3-phenylpyridine) was utilised in the chemoenzymatic synthesis of the corresponding trans-dihydrodiol.

Solventless continuous flow homogeneous hydroformylation of 1-octene

The hydroformylation of 1-octene under continuous flow conditions is described. The system involves dissolving the catalyst, made in situ from [ Rh(acac)(CO)(2)] (acacH = 2,4- pentanedione) and [RMIM][TPPMS] ( RMIM = 1-propyl (Pr), 1-pentyl (Pn) or 1-octyl (O)-3-methyl imidazolium, TPPMS = Ph2P(3-C6H4SO3)), in a mixture of nonanal and 1-octene and passing the substrate, 1-octene, together with CO and H-2 through the system dissolved in supercritical CO2 (scCO(2)). [PrMIM][TPPMS] is poorly soluble in the medium so heavy rhodium leaching (as complexes not containing phosphine) occurs in the early part of the reaction. [PnMIM][ PPMS] affords good rates at relatively low catalyst loadings and relatively low overall pressure (125 bar) with rhodium losses <1 ppm, but the catalyst precipitates at higher catalyst loadings, leading to lower reaction rates. [OMIM][ TPPMS] is the most soluble ligand and promotes high reaction rates, although preliminary experiments suggested that rhodium leaching was high at 5-10 ppm. Optimisation aimed at balancing flows so that the level within the reactor remained constant involved a reactor set up based around a reactor fitted with a sight glass and sparging stirrer with the CO2 being fed by a cooled head HPLC pump, 1-octene by a standard HPLC pump and CO/H-2 through a mass flow controller. The pressure was controlled by a back pressure regulator. Using this set up, [OMIM][ TPPMS] as the ligand and a total pressure of 140 bar, it was possible to control the level within the reactor and obtain a turnover frequency of ca. 180 h(-1). Rhodium losses in the optimised system were 100 ppb. Transport studies showed that 1-octene is preferentially transported over the aldehydes at all pressures, although the difference in mol fraction in the mobile phase was less at lower pressures. Nonanal in the mobile phase suppresses the extraction of 1-octene to some extent, so it is better to operate at high conversion and low pressure to optimise the extraction of the products relative to the substrate. CO and H2 in the mobile phase also suppress the extraction effciency by as much as 80%.

Complex PTSD, interpersonal trauma and relational consequences: Findings from a treatment-receiving Northern Irish sample

Background:
The relationship between PTSD and complex PTSD remains unclear. As well as further addressing this issue, the current study aimed to assess the degree to which DESNOS (complex PTSD) was related to interpersonal trauma and had relational consequences.

Methods:
Eighty one treatment-receiving participants with a history of exposure to the ‘Troubles’ in Northern Ireland, were assessed on various forms of interpersonal trauma, including exposure to the Troubles, and measures of interpersonal and community connectedness.

Results:
DESNOS symptom severity was related to childhood sexual abuse and perceived psychological impact of Troubles-related exposure. A lifetime diagnosis of DESNOS was related to childhood Troubles-related experiences, while a current diagnosis of DESNOS was associated with childhood emotional neglect. PTSD avoidance predicted current DESNOS diagnosis and severity. Feeling emotionally disconnected from family and friends (i.e., interpersonal disconnectedness) was related to all three indices of DESNOS (i.e., lifetime diagnosis, current diagnosis and current symptom severity).

Limitations:
Sample characteristics (i.e., treatment-receiving) and size may limit the generalizability of findings.

Conclusions:
Complex PTSD is associated with PTSD but when present should be considered a superordinate diagnosis.