Arany katalizátorokon lejátszódó heterogén katalitikus folyamatok IR és XPS vizsgálata = IR and XPS studies of heterogeneous catalytic reactions on gold catalysts

Részletes vizsgálatokat végeztünk az NO + CO kölcsönhatás bemutatására Pd/SiO2 katalizátoron. Ezt a programot az indokolta, hogy Goodman és munkatársai (J. Phys. Chem. B 2003, 107, 2759) Pd egykristályon új elnyelési sávot észleltek az NO + CO reakcióban 2258 cm-1-nél , amelyet a Pd-NCO rezgéshez rendeltek. Ez a feltételezés teljesen ellentétben áll korábbi kutatásaink eredményeivel, amely sze- rint a Pd-NCO komplex ilyen magas hőmérsékleten már egyáltalán nem stabilis. 2250-2260 cm-1-nél megjelent elnyelési sávokat csak a HNCO adszorpciójakor észleltük. Mindebből arra következtettünk, hogy a Goodmanék által talált elnyelési sáv semmikép- pen sem tartozhat a Pd-NCO-hoz. Eredményeinket a J. Phys. Chem.B 2004,108 14178- 14180 folyóiratban közöltük. Goodman és munkatársai válaszukban ( Reply to " Com- ment on Combined in situ and infrared kinetic study of the catalytic CO + NO reaction on Pd(III) at pressures up to 240 mbar " Christian Hess, Emrah Ozensoy, and D. Wayne Go- odman ) módosították korábbi elképzelésüket és a 2258 cm-1es sávot a palládiumból ki- diffundáló hidrogén és az NCO közötti kapcsolatból keletkező HNCO képződésének tulajdonították. | It was stated long ago that gold is a catalitically inactive metal because of its 5 d10 configu- ration. Recent publications have, however revealed that gold has a surprisingly high cata- litic activity when it is dispersed over metal oxides, particularly in the oxidation of CO at low temperatures and in the NO + CO reaction. In this project the adsorption, dissociation and reaction of NO with CO has been investigated on supported Au catalysts. The main method was FT IR spectroscopy. Although very limited dissociation of NO was observed on reduced Au catalyst, catalytic tests showed that all the samples used effectively catalyse the NO+CO reaction above 573 K. By means of FTIR spectroscopy several new absorption bands have been detected on the Au samples, the positions of new bands depended on the nature of the support. It was 2212 cm-1 for Au/TiO2 2220-2230 cm-1 for Au/MgO 2256 cm-1 for Au/Al2O3 and 2305 cm-1 for Au/SiO2. These bands were attributed to the asymmetric stretch of NCO attached to the oxides. This idea was strengthened by the results obtained following HNCO adsorption on supports alone which gave the same absorption bands. It was demonstrated and assumed that NCO species is formed on Au crystallites, and then migrates from the Au onto the acceptor sites of support where it is accumulated and stabilized. The Au-NCO species was characterized by an absorption band at 2185-2195 cm-1 produced by the low temperature adsorption of HNCO on Au/SiO2

Evaluation of ADAM-12 as a diagnostic biomarker of ectopic pregnancy in women with a pregnancy of unknown location

Ectopic pregnancy (EP) remains the most life-threatening acute condition in modern gynaecology. It remains difficult to diagnose early and accurately. Women often present at emergency departments in early pregnancy with a 'pregnancy of unknown location' (PUL) and diagnosis/exclusion of EP is challenging due to a lack of reliable biomarkers. Recent studies suggest that serum levels of a disintegrin and metalloprotease protein-12 (ADAM-12) can be used differentiate EP from viable intrauterine pregnancy (VIUP). Here we describe a prospective study evaluating the performance of ADAM-12 in differentiating EP from the full spectrum of alternative PUL outcomes in an independent patient cohort.Sera were collected from 120 patients at their first clinical presentation with a PUL and assayed for ADAM-12 by ELISA. Patients were categorized according to final pregnancy outcomes. Serum ADAM-12 concentrations were increased in women with histologically-confirmed EP (median 442 pg/mL; 25%-75% percentile 232-783 pg/mL) compared to women with VIUP (256 pg/mL; 168-442 pg/mL) or miscarriage (192 pg/mL; 133-476 pg/mL). Serum ADAM-12 did not differentiate histologically-confirmed EP from spontaneously resolving PUL (srPUL) (416 pg/mL; 154-608 pg/mL). The diagnostic potential of ADAM-12 was only significant when 'ambiguous' PUL outcomes were excluded from the analysis (AROC = 0.6633; P = 0.03901).When measured in isolation, ADAM-12 levels had limited value as a diagnostic biomarker for EP in our patient cohort. The development of a reliable serum biomarker-based test for EP remains an ongoing challenge

Corruption and police legitimacy in Lahore, Pakistan

Police legitimacy is an important topic of criminological research, yet it has received only sporadic study in societies where there is widespread police corruption, where the position of the police is less secure, and where social order is more tenuous. Analysing data from a probability sample survey of adults in Lahore, Pakistan, we examine the empirical links between people’s experience of police corruption, their perceptions of the fairness and effectiveness of the police, and their beliefs about the legitimacy of the police. Our findings suggest that in a context in which minimal effectiveness and integrity is yet to be established, police legitimacy may rest not just on the procedural fairness of officers, but also on their demonstrated ability to control crime and avoid corruption

Cyclic AMP increases COX-2 expression via mitogen-activated kinase in human myometrial cells

Cyclic AMP (cAMP) is the archetypal smooth muscle relaxant, mediating the effects of many hormones and drugs. However, recently PGI2, acting via cAMP/PKA, was found to increase contraction-associated protein expression in myometrial cells and to promote oxytocin-driven myometrial contractility. Cyclo-oxygenase-2 (COX-2) is the rate-limiting enzyme in prostaglandin synthesis, which is critical to the onset and progression of human labour. We have investigated the impact of cAMP on myometrial COX-2 expression, synthesis and activity. Three cAMP agonists (8-bromo-cAMP, forskolin and rolipram) increased COX-2 mRNA expression and further studies confirmed that this was associated with COX-2 protein synthesis and activity (increased PGE2 and PGI2 in culture supernatant) in primary cultures of human myometrial cells. These effects were neither reproduced by specific agonists nor inhibited by specific inhibitors of known cAMP-effectors (PKA, EPAC and AMPK). We then used shRNA to knockdown the same effectors and another recently described cAMP-effector PDZ-GEF1-2, without changing the response to cAMP. We found that MAPK activation mediated the cAMP effects on COX-2 expression and that PGE2 acts through EP-2 to activate MAPK and increase COX-2. These data provide further evidence in support of a dual role for cAMP in the regulation of myometrial function