453 research outputs found

    Iridium(i) complexes bearing hemilabile coumarin-functionalised N-heterocyclic carbene ligands with application as alkyne hydrosilylation catalysts

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    A set of iridium(i) complexes of formula IrCl(¿C, ¿2-IRCouR')(cod) or IrCl(¿C, ¿2-BzIRCouR')(cod) (cod = 1, 5-cyclooctadiene; Cou = coumarin; I = imidazolin-2-carbene; BzI = benzimidazolin-2-carbene) have beeen prepared from the corresponding azolium salt and [Ir(µ-OMe)(cod)]2 in THF at room temperature. The crystalline structures of 4b and 5b show a distorted trigonal bipyramidal configuration in the solid state with a coordinated coumarin moiety. In contrast, an equilibrium between this pentacoordinated structure and the related square planar isomer is observed in solution as a consequence of the hemilability of the pyrone ring. Characterization of both species by NMR was achieved at the low and high temperature limits, respectively. In addition, the thermodynamic parameters of the equilibrium, ¿HR and ¿SR, were obtained by VT 1H NMR spectroscopy and fall in the range 22-33 kJ mol-1 and 72-113 J mol-1 K-1, respectively. Carbonylation of IrCl(¿C, ¿2-BzITolCou7, 8-Me2)(cod) resulted in the formation of a bis-CO derivative showing no hemilabile behaviour. The newly synthesised complexes efficiently catalyze the hydrosilylation of alkynes at room temperature with a preference for the ß-(Z) vinylsilane isomer. © The Royal Society of Chemistry

    Minimally invasive management of vital teeth requiring root canal therapy

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    The present study aimed to investigate the possible use of a non-instrumentation technique including blue light irradiation for root canal cleaning. Extracted human single rooted teeth were selected. Nine different groups included distilled water, NaOCl, intra-canal heated NaOCl, and NaOCl + EDTA irrigation after either instrumentation or non-instrumentation, and a laser application group following non-instrumentation technique. The chemical assessment of the root canal dentine was evaluated using EDS and FT-IR. Surface microstructural analyses were performed by using SEM. The antimicrobial efficacy of different preparation techniques was evaluated using microbial tests. Laser application didn’t change the Ca/P, carbonate/phosphate and amide I/phosphate ratios of the root canal dentin the root canal dentin preserved its original form after light application. The instrumentation decreased the carbonate/phosphate and amide I/phosphate ratios of the root canal dentin regardless of the irrigation solution or technique (p < 0.05). According to the microbiological tests, the light application could not provide antibacterial efficacy as much as NaOCl irrigation. The NaOCl irrigation both in the non-instrumentation and instrumentation groups significantly reduced the number of bacteria (p < 0,05). Minimally invasive root canal preparation techniques where the root canal is not instrumented and is disinfected by laser irradiation followed by obturation with a hydraulic cement sealer may be an attractive treatment option for management of vital teeth needing root canal therapy and does not have any detrimental effects on the chemical structure of dentin

    Transumbilical Totally Laparoscopic Single-Port Nissen Fundoplication: A New Method of Liver Retraction: The Istanbul Technique

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    Mustafa Kemal Ataturk, founder of the Turkish Republic, had guarded many German scientists of a Jewish descent before the Second World War. Dr. Rudolf Nissen was one of the outstanding surgeons who had served in the Turkish university hospitals. He had created an antireflux procedure which is named after his own name while he was working in our clinic, the CerrahpaAYa Hospital. From a laparoscopic approach, the Nissen fundoplication was the gold standard intervention for the surgical treatment of gastroesophageal reflux disease (GERD). Currently, video laparoscopic surgery is evolving quickly with the guidance of new technology. Single-port (SP) laparoscopic transumbilical surgery is one of the newest branches of advanced laparoscopy

    Bismuth coating of non-tunneled haemodialysis catheters reduces bacterial colonization: a randomized controlled trial

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    Background. Haemodialysis (HD) catheter-related blood stream infections are a major cause of morbidity and mortality in patients with acute and chronic renal failure

    A catalogue of young runaway Hipparcos stars within 3kpc from the Sun

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    Traditionally runaway stars are O and B type stars with large peculiar velocities.We want to extend this definition to young stars (up to ~50 Myr) of any spectral type and identify those present in the Hipparcos catalogue applying different selection criteria such as peculiar space velocities or peculiar one-dimensional velocities. Runaway stars are important to study the evolution of multiple star systems or star clusters as well as to identify origins of neutron stars. We compile distances, proper motions, spectral types, luminosity classes, V magnitudes and B-V colours and utilise evolutionary models from different authors to obtain star ages and study a sample of 7663 young Hipparcos stars within 3 kpc from the Sun. Radial velocities are obtained from the literature. We investigate the distributions of the peculiar spatial velocity, the peculiar radial velocity as well as the peculiar tangential velocity and its one-dimensional components and obtain runaway star probabilities for each star in the sample. In addition, we look for stars that are situated outside any OB association or OB cluster and the Galactic plane as well as stars of which the velocity vector points away from the median velocity vector of neighbouring stars or the surrounding local OB association/ cluster although the absolute velocity might be small. We find a total of 2547 runaway star candidates (with a contamination of normal Population I stars of 20 per cent at most). Thus, after subtraction of those 20 per cent, the runaway frequency among young stars is about 27 per cent. We compile a catalogue of runaway stars which will be available via VizieR.Comment: 12 pages, 8 figures, 7 tables, accepted for publication in MNRAS old version replaced due to change of the title after journal proof-readin

    Proposing to use artificial neural Networks for NoSQL attack detection

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    [EN] Relationships databases have enjoyed a certain boom in software worlds until now. These days, with the rise of modern applications, unstructured data production, traditional databases do not completely meet the needs of all systems. Regarding these issues, NOSQL databases have been developed and are a good alternative. But security aspects stay behind. Injection attacks are the most serious class of web attacks that are not taken seriously in NoSQL. This paper presents a Neural Network model approach for NoSQL injection. This method attempts to use the best and most effective features to identify an injection. The features used are divided into two categories, the first one based on the content of the request, and the second one independent of the request meta parameters. In order to detect attack payloads features, we work on character level analysis to obtain malicious rate of user inputs. The results demonstrate that our model has detected more attack payloads compare with models that work black list approach in keyword level

    X-ray luminosity function of faint point sources in the Milky Way

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    We assess the contribution to the X-ray (above 2 keV) luminosity of the Milky Way from different classes of low-mass binary systems and single stars. We begin by using the RXTE Slew Survey of the sky at |b|>10 to construct an X-ray luminosity function (XLF) of nearby X-ray sources in the range 10^30<Lx(erg/s)<10^34 (where Lx is the luminosity over 2-10 keV), occupied by coronally active binaries (ABs) and cataclysmic variables (CVs). We then extend this XLF down to Lx~10^27.5 erg/s using the Rosat All-Sky Survey in soft X-rays and available information on the 0.1-10 keV spectra of typical sources. We find that the local cumulative X-ray (2-10 keV) emissivities (per unit stellar mass) of ABs and CVs are (2.0+/-0.8)x10^27 and (1.1+/-0.3)x10^27 erg/s/Msol, respectively. In addition to ABs and CVs, representing old stellar populations, young stars emit locally (1.5+/-0.4)x10^27 erg/s/Msol. We finally attach to the XLF of ABs and CVs a high luminosity branch (up to ~10^39 erg/s) composed of neutron-star and black-hole low-mass X-ray binaries (LMXBs), derived in previous work. The combined XLF covers ~12 orders of magnitude in luminosity. The estimated combined contribution of ABs and CVs to the 2-10 keV luminosity of the Milky Way is ~2x10^38 erg/s, or ~3% of the integral luminosity of LMXBs (averaged over nearby galaxies). The XLF obtained in this work is used elsewhere (Revnivtsev et al.) to assess the contribution of point sources to the Galactic ridge X-ray emission.Comment: 14 pages, 13 figures, revised version accepted for publication in A&
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