Homogeneous Gold Catalysis through Relativistic Effects: Addition of Water to Propyne

In the catalytic addition of water to propyne the Au(III) catalyst is not stable under non-relativistic conditions and dissociates into a Au(I) compound and Cl2. This implies that one link in the chain of events in the catalytic cycle is broken and relativity may well be seen as the reason why Au(III) compounds are effective catalysts.Comment: 12 pages, 3 figures, 1 tabl

Are non-diabetic women with abnormal glucose screening test at increased risk of pre-eclampsia, macrosomia and caesarian birth?

To determine, in non-diabetic women, the relationship of abnormal glucose screening test, with the incidence of pre-eclampsia, macrosomia and caesarian delivery, from 1988-92, 5646 consecutive women attending antenatal clinic were screened with a glucose challenge test (GCT) on their first visit (usually at 16-20 weeks); those with risk factors i.e., history of unexplained perinatal loss, macrosomia or family member with diabetes and an initial abnormal screening test were rescreened at 28-32 weeks, In 482 cases the GCT was abnormal (plasma glucose value was \u3e140 mg% 2 hours after 75g glucose challenge). Of these, 292 had one or more abnormal critical values at a 75g -3 hour oral glucose tolerance test (GTT) and they were treated to maintain euglycaemia. The rest (n=190) had no evidence of glucose intolerance with no abnormal values at the GTT. The subjects were divided into 3 groups based on GCT values; A, randomly selected subjects with a normal GCT (n=1000); B, those with abnormal GCT but normal GTT (n=190); and C, those with abnormal GTT (n=292). The variables studied were age, gravidity, parity, gestational age at delivery, pre-eclampsia, birth-weight and mode of delivery. The incidence of pre-eclampsia and caesarian birth varied, being the lowest in Group A (3.9% and 11.9% respectively) and then rising through group B (6.3% and 16.3% respectively) to the highest in Group C (12.6% and 26.0% respectively; test of linear trend, p\u3c0.05). For macrosomia, the incidence increased from Group A to B but there was a drop in Group C. The incidence of macrosomia was significantly higher for Group B as compared to A or C (9.5% and 3.3%,

Role of the dielectric constant of ferroelectric ceramic in enhancing the ionic conductivity of a polymer electrolyte composite

The dispersal of high dielectric constant ferroelectric ceramic material Ba(0.7)Sr(0.3)TiO(3) (Tc~30 C) and Ba(0.88)Sr(0.12)TiO(3) (Tc~90 C) in an ion conducting polymer electrolyte (PEO:NH4I) is reported to result in an increase in the room temperature ionic conductivity by two orders of magnitude. The conductivity enhancememt "peaks" as we approach the dielectric phase transition of the dispersed ferroelectric material where the dielectric constant changes from ~ 2000 to 4000. This establishes the role of dielectric constant of the dispersoid in enhancing the ionic conductivity of the polymeric composites.Comment: 10 pages, 2 figure

Divergent gold-catalysed reactions of cyclopropenylmethyl sulfonamides with tethered heteroaromatics

Cyclopropenylmethyl sulfonamides with tethered heteroaromatics have been demonstrated to undergo divergent gold-catalysed cyclisation reactions. A formal dearomative (4+3) cycloaddition takes place with furan-tethered substrates, yielding densely functionalised 5,7-fused heterocycles related to the bioactive curcusone natural products. Indole-tethered substrates display divergent reactivity giving biologically important tetrahydro-β-carbolines via a Friedel-Crafts mechanism

Proton supplier role of binuclear gold complexes in promoting hydrofunctionalisation of nonactivated alkenes

Density functional theory (DFT) was used to investigate PR 3 AuOTf-catalyzed hydrofunctionalisation of nonactivated alkenes using acetic acid and phenol where OTf = triflate (CF 3 SO 3- ). The gold(i) complex itself is found to be unlikely to operate as the π-activator due to its relatively low electrophilicity. Instead, the concurrent coordination of two gold(i) complexes to a nucleophile (PhOH or AcOH) enhances the acidity of the latter\u27s proton and causes the ensuing binuclear complex to serve as a strong proton supplier for activating the alkene π-bonds. Alternatively, the binuclear complex is also susceptible to produce a hidden HOTf. This hidden acid is accessible for hydrofunctionalization to occur but it is not in sufficient concentration to decompose the final product

Temporomandibular Joint Ankylosis as a Complication of Neonatal Septic Arthritis : Report of two cases

Temporomandibular joint (TMJ) ankylosis as a complication of neonatal septic arthritis is rarely reported in the literature. We report two clinical cases of unilateral TMJ ankylosis occurring in paediatric patients subsequent to neonatal septic arthritis. The first case was a 15-month-old male infant who presented to the Sultan Qaboos University Hospital, Muscat, Oman, in May 2010. According to the published English scientific literature, he is the youngest person yet to be diagnosed with this condition. The second case was a five-year-old female who presented to the Al-Nahda Hospital, Muscat, Oman, in October 2011. Both cases presented with facial asymmetry and trismus. They subsequently underwent gap arthroplasty and interpositional temporalis muscle and fascia grafts which resulted in an immediate improvement in mouth opening. Postoperatively, the patients underwent active jaw physiotherapy which was initially successful. Both patients were followed up for a minimum of two years following their surgeries

Cystathione gamma lyase/hydrogen sulphide pathway up regulation enhances the responsiveness of ?1A and ?1B-adrenoreceptors in the kidney of rats with left ventricular hypertrophy

The purpose of the present study was to investigate the interaction between H2S and NO (nitric oxide) in the kidney and to evaluate its impact on the functional contribution of ?1A and ?1B-adrenoreceptors subtypes mediating the renal vasoconstriction in the kidney of rats with left ventricular hypertrophy (LVH). In rats the LVH induction was by isoprenaline administration and caffeine in the drinking water together with intraperitoneal administration of H2S. The responsiveness of ?1A and ?1B to exogenous noradrenaline, phenylephrine and methoxaminein the absence and presence of 5-methylurapidil (5-MeU) and chloroethylclonidine (CEC) was studied. Cystathione gamma lyase (CSE), cystathione ? synthase (CBS), 3-mercaptopyruvate sulphar transferase (3-MST) and endothelial nitric oxide synthase (eNOS) were quantified. There was significant up regulation of CSE and eNOS in the LVH-H2S compared to the LVH group (P<0.05). Baseline renal cortical blood perfusion (RCBP) was increased (P<0.05) in the LVH-H2S compared to the LVH group. The responsiveness of ?1A-adrenergic receptors to adrenergic agonists was increased (P<0.05) after administration of low dose 5-Methylurapidil in the LVH-H2S group while ?1B-adrenergic receptors responsiveness to adrenergic agonists were increased (P<0.05) by both low and high dose chloroethylclonidine in the LVH-H2S group. Treatment of LVH with H2S resulted in up-regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways in the kidney. These up regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways enhanced the responsiveness of ?1A and ?1B-adrenoreceptors subtypes to adrenergic agonists in LVH-H2S. These findings indicate an important role for H2S in modulating deranged signalling in the renal vasculature resulting from LVH development

A Detailed Cloud Fraction Climatology of the Upper Indus Basin and Its Implications for Near-Surface Air Temperature*

implications for near surface air temperature. Journal of Climate 2015, 28(9)

Catalytic Intermolecular Hetero-Dehydro-Diels–Alder Cycloadditions: Regio- and Diasteroselective Synthesis of 5,6-Dihydropyridin-2-ones

A novel catalyzed intermolecular heterodehydro-Diels–Alder reaction between push–pull 1,3-dien-5-ynes and aldimines or silylaldimines is reported. The sequence is promoted both by gold(I) or silver(I) catalysts and leads to the diastereo- and regioselective formation of 5,6-dihydropyridin-2-onesMICINN (Spain) (grants CTQ2009-09949, CTQ2010-16790, PTA2008-1524-P contract to J.M.F.-G. and Ramon y Cajal postdoctoral contract to M.A.F.-R.) and FICYT (project IB08-088)This document is the Accepted Manuscript version of a Published Work that appeared in final form in Organic letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/page/policy/articlesonrequest/index.htm