1,952 research outputs found

    Improved catalytic activity of ruthenium–arene complexes in the reduction of NAD+

    Get PDF
    A series of neutral Ru-II half-sandwich complexes of the type [(eta(6)-arene)Ru(N,N')Cl] where the arene is para-cymene (p-cym), hexamethylbenzene (hmb), biphenyl (bip), or benzene (bn) and N,N' is N-(2-aminoethyl) -4-(trifluoromethyl)benzenesulfonamide (TfEn), N-(2-aminoethyl)-4-toluenesulfonamide (TsEn), or N-(2-aminoethyl)-methylenesulfonamide (MsEn) were synthesized and characterized. X-ray crystal structures of [(p-cym)Ru(MsEn)Cl] (1), [(hmb)Ru(TsEn)Cl] (5), [(hmb)Ru(TfEn)Cl] (6), [(bip)Ru(MsEn)Cl] (7), and [(bip)Ru(TsEn)Cl] (8) have been determined. The complexes can regioselectively catalyze the transfer hydrogenation of NAD(+) to give 1,4-NADH in the presence of formate. The turnover frequencies (TOF) when the arene is varied decrease in the order bn > bip > p-cym > hmb for complexes with the same N,N' chelating ligand. The TOF decreased with variation in the N,N' chelating ligand in the order TfEn > TsEn > MsEn for a given arene. [(bn)Ru(TfEn)Cl] (12) was the most active, with a TOP of 10.4 h(-1). The effects of NAD(+) and formate concentration on the reaction rates were determined for [(p-cym)Ru(TsEn)Cl] (2). Isotope studies implicated the formation of [(arene)Ru(N,N')(H)] as the rate-limiting step. The coordination of formate and subsequent CO2 elimination to generate the hydride were modeled computationally by density functional theory (DFT). CO2 elimination occurs via a two-step process with the coordinated formate first twisting to present its hydrogen toward the metal center. The computed barriers for CO2 release for arene = benzene follow the order MsEn > TsEn > TfEn, and for the Ms En system the barrier followed bn < hmb, both consistent with the observed rates. The effect of methanol on transfer hydrogenation rates in aqueous solution was investigated. A study of pH dependence of the reaction in D2O gave the optimum pH* as 7.2 with a TOF of 1.58 h(-1) for 2. The series of compounds reported here show an improvement in the catalytic activity by an order of magnitude compared to the ethylenediamine analogues

    Designing organometallic compounds for catalysis and therapy

    Get PDF
    Bioorganometallic chemistry is a rapidly developing area of research. In recent years organometallic compounds have provided a rich platform for the design of effective catalysts, e.g. for olefin metathesis and transfer hydrogenation. Electronic and steric effects are used to control both the thermodynamics and kinetics of ligand substitution and redox reactions of metal ions, especially Ru II. Can similar features be incorporated into the design of targeted organometallic drugs? Such complexes offer potential for novel mechanisms of drug action through incorporation of outer-sphere recognition of targets and controlled activation features based on ligand substitution as well as metal- and ligand-based redox processes. We focus here on η 6-arene, η 5-cyclopentadienyl sandwich and half-sandwich complexes of Fe II, Ru II, Os II and Ir III with promising activity towards cancer, malaria, and other conditions. © 2012 The Royal Society of Chemistry

    Comorbid depression and anxiety effects on pregnancy and neonatal outcome

    Get PDF
    The effects of comorbid depression and anxiety were compared to the effects of depression alone and anxiety alone on pregnancy mood states and biochemistry and on neonatal outcomes in a large multi-ethnic sample. At the prenatal period the comorbid and depressed groups had higher scores than the other groups on the depression measure. But, the comorbid group had higher anxiety, anger and daily hassles scores than the other groups, and they had lower dopamine levels. As compared to the non-depressed group, they also reported more sleep disturbances and relationship problems. The comorbid group also experienced a greater incidence of prematurity than the depressed, the high anxiety and the non-depressed groups. Although the comorbid and anxiety groups were lower birthweight than the non-depressed and depressed groups, the comorbid group did not differ from the depressed and anxiety groups on birth length. The neonates of the comorbid and depressed groups had higher cortisol and norepinephrine and lower dopamine and serotonin levels than the neonates of the anxiety and non-depressed groups as well as greater relative right frontal EEG. These data suggest that for some measures comorbidity of depression and anxiety is the worst condition (e.g., incidence of prematurity), while for others, comorbidity is no more impactful than depression alone.This research was supported by a Merit Award (MH #46586), an NIH grant (AT #00370) and Senior Research Scientist Awards (MH #0033 1 and AT #001585) and a March of Dimes Grant (#12-FYO3-48) to Tiffany Field and funding from Johnson and Johnson Pediatric Institute to the Touch Research Institute

    Hygrothermal simulation-informed design of mesoporous desiccants for optimised energy efficiency of mixed mode air conditioning systems

    Get PDF
    This paper describes an optimization technique using hygrothermal numerical modelling to determine an ideal and unknown isotherm in order to inform the design of optimised mesoporous desiccants. Their suitability for passive humidity buffering as well as their impact on energy efficiency was assessed when assisting a mixed mode air-conditioning (AC) system. Three clear stages of water vapour adsorption were found that strongly correspond to the Dw gradient when assessing the kinetics of adsorption and exchange rates for periodic moisture loads. Consistent agreement was found between the latent heat of dehumidification used by the AC system and the desiccant decay time after successive sorption loop cycles. This confirmed the material's suitability for specific applications and was found to be highly sensitive to the portion of the isotherm between φi,L - φi,U (Dw gradient), compared with full adsorption capacity (total w) when assessing total energy consumption. The experimental results of sorption kinetics appeared to be slightly underestimated between the Dw gradient and the response time to reach equilibrium moisture content (EMC). The major underestimations were found to be consistent with the kinetics of adsorption/desorption when analysing their significance based on w differences. These were largely attributed to a combination of adsorption kinetics (time-response) and adsorption/desorption hysteresis. However, this was not evident when comparing long-term experimental data and numerical estimations for water vapour sorption isotherms, since numerical model accurately predicted them. This suggests that both adsorption kinetics and the scanning curve prediction, within a hysteresis loop, are not accurately represented by current hygrothermal models and are hence a priority for future research

    Variations dans les réactions face à des scénarios fantasmatiques : une analyse de classes latentes

    Get PDF
    Les fantasmes sexuels représentent une dimension de la sexualité humaine intime, personnelle et diversifiée. Néanmoins, la recherche à ce sujet demeure limitée en s'étant principalement intéressée aux fantasmes sexuels en termes de leurs fréquences et leurs contenus. Par conséquent, peu de recherches ont examiné les réactions que peuvent provoquer les fantasmes chez les individus. Dans le but d'explorer cette relation , une analyse de classe latente a été réalisée auprès de 566 hommes et femmes adultes issus de la population générale du Canada et des États-Unis, qui ont complété un questionnaire en ligne incluant des mesures de réactions (inconfort et excitation) face à quatre scénarios fantasmatiques proposés. Quatre classes ont été identifiées: 1) les Indifférents, qui rapportent des niveaux d'inconfort et d'excitation relativement faibles ; 2) les Romantiques, qui rapportent une excitation élevée et un inconfort faible seulement face au scénario de romantisme ; 3) les Excités, qui sont caractérisés par une excitation élevée et un inconfort faible face à tous les scénarios et 4) les Dissonants, caractérisés par des niveaux d'inconf011 et d'excitation relativement élevés face à tous les scénarios. Les comparaisons entre les quatre classes révèlent des différences quant à l'attachement romantique, la compulsion sexuelle et l'agression sexuelle en enfance. Les résultats illustrent des schémas distincts de réactions face à des scénarios fantasmatiques proposés et indiquent des liens entre ces réactions, l'agression sexuelle en enfance et certaines caractéristiques psychosexuelles. Ceci suggère que les réactions face aux fantasmes sexuels seraient des éléments clés dans la compréhension des interactions entre les fantasmes et d'autres aspects de la sexualité humaine. _____________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : fantasmes sexuels, fantasmatique, sexualité, analyses de classes latente

    Organoiridium complexes : anticancer agents and catalysts

    Get PDF
    Iridium is a relatively rare precious heavy metal, only slightly less dense than osmium. Researchers have long recognized the catalytic properties of square-planar Ir(I) complexes, such as Crabtree's hydrogenation catalyst, an organometallic complex with cyclooctadiene, phosphane, and pyridine ligands. More recently, chemists have developed half-sandwich pseudo-octahedral pentamethylcyclopentadienyl Ir(III) complexes containing diamine ligands that efficiently catalyze transfer hydrogenation reactions of ketones and aldehydes in water using H2 or formate as the hydrogen source. Although sometimes assumed to be chemically inert, the reactivity of low-spin 5d(6) Ir(III) centers is highly dependent on the set of ligands. Cp* complexes with strong σ-donor C^C-chelating ligands can even stabilize Ir(IV) and catalyze the oxidation of water. In comparison with well developed Ir catalysts, Ir-based pharmaceuticals are still in their infancy. In this Account, we review recent developments in organoiridium complexes as both catalysts and anticancer agents. Initial studies of anticancer activity with organoiridium complexes focused on square-planar Ir(I) complexes because of their structural and electronic similarity to Pt(II) anticancer complexes such as cisplatin. Recently, researchers have studied half-sandwich Ir(III) anticancer complexes. These complexes with the formula [(Cp(x))Ir(L^L')Z](0/n+) (with Cp* or extended Cp* and L^L' = chelated C^N or N^N ligands) have a much greater potency (nanomolar) toward a range of cancer cells (especially leukemia, colon cancer, breast cancer, prostate cancer, and melanoma) than cisplatin. Their mechanism of action may involve both an attack on DNA and a perturbation of the redox status of cells. Some of these complexes can form Ir(III)-hydride complexes using coenzyme NAD(P)H as a source of hydride to catalyze the generation of H2 or the reduction of quinones to semiquinones. Intriguingly, relatively unreactive organoiridium complexes containing an imine as a monodentate ligand have prooxidant activity, which appears to involve catalytic hydride transfer to oxygen and the generation of hydrogen peroxide in cells. In addition, researchers have designed inert Ir(III) complexes as potent kinase inhibitors. Octahedral cyclometalated Ir(III) complexes not only serve as cell imaging agents, but can also inhibit tumor necrosis factor α, promote DNA oxidation, generate singlet oxygen when photoactivated, and exhibit good anticancer activity. Although relatively unexplored, organoiridium chemistry offers unique features that researchers can exploit to generate novel diagnostic agents and drugs with new mechanisms of action

    Étude de la réponse immunitaire cérébrale innée dans la pathogenèse de l'encéphalite herpétique et évaluation de stratégies immunomodulatrices

    Get PDF
    La pathogenèse de l’encéphalite herpétique (HSE) n’est pas totalement connue, mais la réplication du virus engendre une encéphalite aiguë nécrosante du lobe temporal/frontal et une inflammation cérébrale menant à l’infiltration des cellules immunitaires périphériques au sein du système nerveux central. Bien que la majorité des dommages cérébraux engendrés seraient causés par la réplication virale, de plus en de plus de données indiquent une composante immunitaire dans la pathogenèse de l’HSE. La réponse immunitaire innée constitue la première ligne de défense limitant la propagation virale. Nous savons que la réponse immunitaire est engendrée à la suite de la reconnaissance du VHS-1, notamment par les « Toll-like receptors » (TLRs). De plus, la synthèse d’interféron (IFN) de type I est primordiale dans la réponse antivirale. En effet, des études montrent qu’une déficience d’un composant impliqué dans les voies de signalisation menant à la production d’IFNs de type I est délétère chez la souris et chez l’humain au cours de l’HSE. Par ailleurs, la migration des cellules immunitaires au sein du SNC prend de plus en plus d’ampleur dans l’étude de la réponse immunitaire contre cette infection. Cependant, bien que différents modèles animaux permettent l’étude de la réponse immunitaire cérébrale, la complexité de cette pathologie, du SNC et de sa réponse inflammatoire en limite encore notre compréhension. L’objectif principal de cette thèse a été de mieux comprendre la composante immunitaire de la pathogenèse de l’HSE, et plus spécifiquement, au niveau du recrutement des cellules immunitaires périphériques dans le SNC, de la participation des voies de signalisation passant par les facteurs de transcription régulateurs des IFNs (IRF) 3 et IRF7 et d’évaluer l’effet d’immunomodulateurs tels que l’artésunate et la rapamycine sur la sensibilité de différentes souches murines au cours de l’encéphalite herpétique expérimentale. Les études menées ont permis de mettre en évidence qu’une réponse immunitaire cérébrale innée efficace participe à la résistance naturelle des souris C57BL/6 en comparaison aux souris BALB/c naturellement sensibles. En effet, la charge virale dans le SNC des souris C57BL/6 infectées par le VHS-1 par voie I.N est plus faible au pic de l’infection (i. e jour 6 post-infection [p. i]) comparativement aux souris BALB/c. Ce contrôle de la charge virale est associé à une infiltration rapide (avec au jour 4 post-infection, infiltration de monocytes inflammatoires, de cellules dendritiques conventionnelles [cDCs], de cellules dendritiques plasmacytoïdes [pDCs], de cellules « natural killers » [NK], de cellules « natural killers T » [NKT]) et coordonnée (suivie d’une infiltration de lymphocyte T au jour 8 p. i). Par ailleurs, les travaux réalisés ont permis de mettre en évidence un rôle clé d’IRF3 et plus particulièrement d’IRF7 dans la réponse interféron de type I. En ce sens, les souris déficientes pour IRF3 ou IRF7 sont plus sensibles à l’infection intranasale par le VHS-1 que les souris C57BL/6 sauvages. Chez les souris déficientes pour IRF7 et dans une moindre mesure pour IRF3, la perte de contrôle de la réplication virale dans le cerveau est associée à un défaut de production d’IFN -b à un temps précoce après l’infection suivi par une surproduction des IFNs de type I. La sensibilité accrue au cours de l’HSE, aussi bien chez les souris BALB/c naturellement sensibles que chez les souris déficientes pour IRF7 ou IRF3, est combinée à une forte production de cytokines pro-inflammatoires et de chimiokines à des temps tardifs postinfection. Nous avons donc évalué l’effet de l’ajout d’immunomodulateurs au traitement antiviral : l’artésunate (ART), agissant sur les voies de signalisation passant par TLR2 et 9 et la rapamycine (RAPA), agissant sur les voies de signalisation passant par TLR3 et 9 et ainsi mis en évidence que l’ajout d’un composé immunomodulateur au traitement antiviral permettait d’améliorer la survie des souris sensibles à l’infection sans action directe sur la charge virale au niveau du cerveau, mais en diminuant significativement les taux de cytokines pro-inflammatoire et de chimiokines dans le SNC. À l’aide de ces différents modèles expérimentaux, j’ai également démontré une surexpression de cytokines pro-inflammatoires (l’IL-1 b, l’IL-6, l’IFN -g) et de chimiokine (CCL2), dont les taux sont diminués par l’ajout d’un traitement immunomodulateur à la thérapie antivirale dans un modèle murin sensible à l’HSE. Ces données apportent donc de nouvelles preuves d’une composante immunitaire dans la pathogenèse de l’encéphalite herpétique, ainsi que de nouvelles cibles thérapeutiques potentielles.Pathogenesis of herpes simplex encephalitis is not completely understood, but viral replication results in acute necrotizing encephalitis of the temporal/frontal lobes and cerebral inflammation leading to the infiltration of the peripheral immune cells to the central nervous system (CNS). Although most brain damage is caused by viral replication, a lot of data suggest that the immune response could also contribute to the pathogenesis of HSE. The innate immune response is the first line of host defense that limits viral spread. Numerous studies showed that the immune response is induced by the recognition of HSV-1, in particular by the toll-like receptors (TLRs). Likewise, type I interferon (IFN) is essential to the antiviral response. Indeed, studies showed that impairment of a component involved in signaling pathways inducing the type I IFN synthesis is deleterious in mice and humans during HSE. For several years, a series of studies have suggested that the immune response participated in this CNS pathology resulting in a fatal course and that hyperinflammatory responses initiated by early infiltrating innate cells play a key role in the development of this pathology. In addition, the complexity of the CNS inflammatory response constitutes a challenge for our understanding of the pathogenesis of herpetic encephalitis. The main objective of this thesis was to better understand the immune response as a contributor to the pathogenesis of HSE, and more specifically, the recruitment of peripheral immune cells in the CNS, the involvement of signaling pathway mediated by the interferon regulatory transcription factors (IRF) 3 and IRF7 and the evaluation of the effects of immunomodulators such as artesunate and rapamycin on the susceptibility of different murine strains during experimental HSE An effective innate cerebral immune response contributes to the natural resistance of C57BL/6 mice compared to naturally sensitive BALB/c mice. In fact, the viral load in the CNS of C57BL/6 mice infected with HSV-1 by the I.N. route is lower at the peak of infection (day 6 post-infection (p.i)) compared to BALB/c mice. This control of the viral load is associated with rapid and coordinated infiltration of cells in the CNS (infiltration of inflammatory monocytes, conventional dendritic cells (cDCs), plasmacytoid dendritic cells (pDCs), natural killer cells (NK), natural killer cells T (NKT) on day 4 p.i) followed by T lymphocyte infiltration on day 8 p.i. Moreover, the control of viral replication is orchestrated by the activation of transcription factors IRF3 and particularly IRF7. In this regard, mice deficient for IRF3 or IRF7 are more susceptible to intranasal infection by HSV-1 than wild type C57BL/6 mice. In mice deficient for IRF7 and to a lesser extent for IRF3, the loss of control of viral replication in the brain is associated with a defect in IFN-b production at an early time after infection followed by overproduction of type I IFNs. Increased susceptibility of BALB/c mice, IRF3- or IRF7-deficient mice is associated with higher levels of pro-inflammatory cytokines and chemokines levels in the CNS compared to C57BL/6 mice at later times post-infection. We therefore evaluated the effect of the addition of immunomodulators to antiviral treatment: artesunate (ART), acting on signaling pathways mediated by TLR2 and 9 and rapamycin (RAPA), acting on signaling pathways mediated by TLR3 and 9. We show that the administration of ART or RAPA to the antiviral therapy was beneficial and improve the outcome of HSE in mice, without a direct effect on the viral load. Instead they act by decreasing significantly pro-inflammatory cytokine and chemokine levels in the CNS. Using these different experimental models, we also demonstrated overexpression of pro-inflammatory cytokines (IL-1 b, IL-6, IFN -g) and chemokine (CC2) during experimental HSE. In this regard, adding of immunomodulatory compound to antiviral therapy allowed to decrease levels of these inflammatory proteins. In conclusion, these data provide new evidence for the contribution of the immune response in the pathogenesis of herpetic encephalitis, as well as the development of potential new therapeutic targets

    Canal de Provence

    Get PDF
    Presented at the 2002 USCID/EWRI conference, Energy, climate, environment and water - issues and opportunities for irrigation and drainage on July 9-12 in San Luis Obispo, California.Includes bibliographical references.Measurement network on hydraulic system includes many sensors subject to failure or deviation, and spread over a huge area. In addition discharge and volume measurements in open channel hydraulic networks are characterized by large uncertainties. To overcome this kind of problem, in process control industrial applications, data reconciliation is more and more used. The objective of the data reconciliation is to take advantage of information redundancy on a system to make a cross-checking of real-time measurements. Using this information redundancy, a data reconciliation module allows to detect inconsistent measurements, measurement deviations and provides corrected values whether the initial measurements are valid, biased or invalid. A derived consequence is to better schedule the maintenance of sensors. A data reconciliation module, based on the measurements from the hydraulic network, has been recently developed and implemented in the SCP's supervisory system. The software has initially been used on a daily basis to check the measured flow on the main canal. It has then been adapted in order to run every 15 minutes on a distribution network including pipes, canals, and tanks. The paper presents first the theory of the Canal de Provence data reconciliation application. The basic model is an hydraulic network with a series of nodes corresponding to balance equations (inflows, outflows, and storage). Constrained data reconciliation is used in order to satisfy the non-negativity of the hydraulic variables and the mass balance relations. The results are corrected values for measured variables and proposed values for non-measured quantities. A statistical analysis of the results is performed. This analysis allows to evaluate the uncertainties attached to the estimated flows and volume values. It allows also to detect invalid measurements, drift of sensors and to decide which maintenance operations to perform. Secondly, field examples are presented: measured and re-estimated flow values with their standard deviations, detection of invalid sensors, performed maintenance operation. The data reconciliation is situated just after the measurement process and takes place in the decision process for diagnosis, identification and control
    corecore