69 research outputs found

    Factors Influencing Utilization of Artificial Nesting Cylinders by Mallards and Wood Ducks in Northwest Pennsylvania and Southern Ontario

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    Factors influencing utilization of elevated nesting structures by waterfowl were examined in southern Ontario and northwest Pennsylvania, 2006-2008. In the final-year, Mallard occupancy rates were 18 % in Pennsylvania and 16 % in Ontario. Mean nest success was 77 ± 20 % for combined sites (2006-2008). Final-year Wood Duck occupancy rates were 12 % in Pennsylvania and 2 % in Ontario; mean nest success was 70 ± 29 %. Mallards tended to select structures in areas with high wetland densities and adjacent to grasslands or hayfields. In Pennsylvania, Wood Ducks had similar preferences for structures as did Mallards. In Ontario, Wood Ducks were more likely to use structures with a high proportion of adjacent forest cover and a high abundance of invertebrates. Cost per duckling fledged was 20.00withapaidtechnicianand20.00 with a paid technician and 5.24 if structures are maintained by volunteers. Relative to other management strategies, artificial nesting cylinders may be cost effective for increasing Mallard populations in Ontario and Pennsylvania

    Modelling of Spark Ignition in Turbulent Reacting Droplet-laden Temporally Evolving Jet using LES

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    The turbulent jet flames in fuel sprays are of a great importance and are used in many practical applications, e.g., aircraft and automotive direct fuel injection systems. In this work we analyse the process of spark ignition in two-phase temporally evolving jet which carries the fuel spray. We focus on a dependence of the ignition on local flow structures, spark parameters and fuel droplets size. The fuel (n-Heptane) spray evaporates and mixes with the co-flowing oxidizer (air) creating a flammable mixture. The spark is modelled as a source term added to the energy equation. The goal of the research is to investigate the forced ignition and subsequent flame propagation/extinction in the low Mach number turbulent flow. The computations are carried out using Implicit Large Eddy Simulation (ILES) method by the high-order in-house LES solver. Liquid droplets are modelled in Lagrangian reference frame as point sources of mass, momentum and energy. The results show that combined effect of local fuel concentration, strain rate and scalar dissipation rate plays a main role in ignition. On the other hand, high rates of strain at the spark position cause substantial flame stretching leading to its extinction

    Phosphoinositide-dependent protein kinase-1 (PDK1)-independent activation of the protein kinase C substrate, protein kinase D

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    Phosphoinoisitide dependent kinase l (PDK1) is proposed to phosphorylate a key threonine residue within the catalytic domain of the protein kinase C (PKC) superfamily that controls the stability and catalytic competence of these kinases. Hence, in PDK1-null embryonic stem cells intracellular levels of PKCalpha, PKCbeta1, PKCgamma, and PKCepsilon are strikingly reduced. Although PDK1-null cells have reduced endogenous PKC levels they are not completely devoid of PKCs and the integrity of downstream PKC effector pathways in the absence of PDK1 has not been determined. In the present report, the PDK1 requirement for controlling the phosphorylation and activity of a well characterised substrate for PKCs, the serine kinase protein kinase D, has been examined. The data show that in embryonic stem cells and thymocytes loss of PDK1 does not prevent PKC-mediated phosphorylation and activation of protein kinase D. These results reveal that loss of PDK1 does not functionally inactivate all PKC-mediated signal transduction

    Nrf2 stabilization prevents critical oxidative damage in Down syndrome cells

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    Mounting evidence implicates chronic oxidative stress as a critical driver of the aging process. Down syndrome (DS) is characterized by a complex phenotype, including early senescence. DS cells display increased levels of reactive oxygen species (ROS) and mitochondrial structural and metabolic dysfunction, which are counterbalanced by sustained Nrf2-mediated transcription of cellular antioxidant response elements (ARE). Here, we show that caspase 3/PKCδdependent activation of the Nrf2 pathway in DS and Dp16 (a mouse model of DS) cells is necessary to protect against chronic oxidative damage and to preserve cellular functionality. Mitochondria-targeted catalase (mCAT) significantly reduced oxidative stress, restored mitochondrial structure and function, normalized replicative and wound healing capacity, and rendered the Nrf2-mediated antioxidant response dispensable. These results highlight the critical role of Nrf2/ARE in the maintenance of DS cell homeostasis and validate mitochondrial-specific interventions as a key aspect of antioxidant and antiaging therapies.Fil: Zamponi, Emiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Zamponi, Nahuel. Cornell University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Coskun, Pinar. University of California at Irvine; Estados UnidosFil: Quassollo Infanzon, Gonzalo Emiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Lorenzo, Alfredo Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Cannas, Sergio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Pigino, Gustavo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Chialvo, Dante Renato. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Gardiner, Katheleen. University of Colorado Denver. School of Medicine; Estados UnidosFil: Busciglio, Jorge. University of California at Irvine; Estados UnidosFil: Helguera, Pablo Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentin

    Queer Erections: Counter-Monuments for the Counter-Culture

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    Durant la darrera dècada s'ha començat un procés de revaluació de les qüestions plantejades pels artistes i dissenyadors alemanys de la postguerra que intentaven crear un nou paradigma per construir monuments amb una perspectiva postmoderna. Amb un especial interès en els monuments LGBTQ+ a Europa, aquest projecte busca definir els principis d’un “disseny queer” i com es podrien implementar en projectes amb la intenció de revitalitzar el ‘Gaixample’ – un barri històricament ocupat per la comunitat gai a l'Eixample de Barcelona. Treballant a partir de l'arquitectura visionària i l’antidisseny, s’intenta crear una sèrie de “monuments moderns a la diversitat”. Tres possibles visions del disseny (Dissenyador com a Creador, Dissenyador com a Provocador, Dissenyador com a Catalitzador) donen origen a sis intervencions de disseny urbà que interactuen amb la història i l’experiència LGBTQ+. Es diu que el monument modern és una paradoxa i les tendències del pensament contemporani disminueixen la necessitat d’aquestes estructures, però l’objectiu de Queer Erections és posar de manifest la importància d’aquests monuments per a la societat contemporània.In the last decade, we have started to re-examine the questions posed by Post-War German artists and designers as they looked toward a new standard of building monuments with a post-modern perspective. With a special look at LGBTQ+ Monuments in Europe, this project looks to define principles of “queer design” and how to apply them to projects meant to reinvigorate Gaixample – an historically gay neighborhood in Barcelona’s Eixample district. Using Visionary Architecture and Anti-Design as starting points, the aim is to create a series of “modern monuments to diversity”. Three possible approaches to design (Designer as Creator, Designer as Provocateur, Designer as Catalyst) lead to six urban design interventions which engage with LGBTQ+ history and experiences. It is said that a modern monument is a paradox, and the prevailing winds are pushing back on the need for such structures, but the aim of Queer Erections to showcase how valuable monuments can be in contemporary society

    Impact of subgrid modelling and numerical method on autoignition simulation of two-phase flow

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    The present work focuses on analyses of the autoignition delay time predicted by the large eddy simulation (LES) method by applying different subgrid scales (SGS) models and two different discretization schemes. The analysed flow configuration is a two-phase chemically reacting turbulent flow with monodispersed evaporating fuel droplets. The impact of numerical procedure is investigated in a 3D flow domain with a temporally evolving mixing layer that constituted between the streams of fuel and oxidizer that moved in opposite directions. The upper stream of cold gas carries a dispersed fuel spray (ethanol at 300 K). The lower stream is a hot air at 1000 K. Three commonly used in LES, SGS models are investigated, namely: classical Smagorinsky model, model proposed by Vreman and the σ-model proposed by Nicoud. Additionally, the impact of two discretization schemes, i.e., total variation diminishing (TVD) and weighted essentially nonoscillatory (WENO) is analysed. The analysis shows that SGS model and discretization scheme can play a crucial role in the predictions of the autoignition time. It is observed that for TVD scheme the impact of SGS model is rather small. On the contrary, when the WENO scheme is applied the results are much more dependent on the SGS model

    Expression and purification of the SARS coronavirus m<sup>pro</sup> and its co-crystallization with specific inhibitors

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    Bei SARS („Schweres akutes respiratorisches Syndrom“) handelt es sich um eine Infektionskrankheit des Menschen, welche im November 2002 erstmalig auftrat. Als Erreger dieser Krankheit wurde das SARS-assoziierte Coronavirus identifiziert. Dessen viruseigene Reproduktionsmaschinerie wird vor allem durch die katalytische Aktivität einer Cysteinprotease, der SARS-Coronavirus-Hauptprotease (SARS-CoV-Mpro), und die damit verbundene Prozessierung von viralen Polyproteinen, aufrechterhalten. Diese Schlüsselfunktion der SARS-CoV-Mpro macht sie zu einem vielversprechenden Zielobjekt bei der Entwicklung von spezifischen Inhibitoren für diese Protease, welche somit eine Vermehrung des Virus verhindern. In dieser Arbeit wurde die SARS-CoV-Mpro mit optimierten Methoden exprimiert und gereinigt. Mit der Methode der ESI-MS-Analyse konnte ein kovalentes, irreversibles Bindungsverhalten verschiedener Inhibitoren gezeigt werden und erstmals auch die Bindung von Fragmenten von Inhibitormolekülen an die Protease. So zeigten die SARS-CoV-Mpro-Inhibitoren MH211A und UK-VI-1g eine kovalente Bindung des kompletten Moleküls pro Enzym-Monomer: überraschenderweise hatten bis zu vier Moleküle MH211A bzw. zwei Moleküle UK-VI-1g an ein Proteasemolekül gebunden. Die Bindung von UK-VI-1g an die Protease wurde an zwei Peptiden im Bereich von den Aminosäuren 62 bis 76 bzw. 280 bis 298 nachgewiesen, wobei beide nicht in der Nähe der active site lokalisiert sind. Im Falle des Inhibitors Lit1 bindet der 2,6-Dinitro-4-trifluoromethyl-phenyl-Rest, bei TS48 das Zimtsäure-Thioester-Fragment kovalent an jedes Monomer im dimeren Enzym. Die SARS-CoV-Mpro wurde erstmals ohne Abtrennung des C-terminalen His-tag mit spezifischen Inhibitoren co-kristallisiert. Drei mögliche Orientierungen des Inhibitors TS174 wurden in der active site der Protease identifiziert. Aufgrund der schwachen Elektronendichte des Inhibitors konnten diese nicht weiter untersucht werden. Das Iod-Isatin-Derivat IISBT wurde ebenfalls mit der SARS-CoV-Mpro zusammen co-kristallisiert und es konnte erstmalig eine kovalente Bindung eines Isatin-Derivats an die SARS-CoV-Mpro anhand einer Röntgenstruktur klar gezeigt werden. Diese Struktur zeigte dann, dass früher veröffentlichte molekulare docking-Studien, die eine nicht-kovalente Bindung von IISBT und anderen Isatin-Derivaten veranschaulichen, nochmal überdacht werden sollten. Basierend auf einer ESI-MS-Analyse und früheren Ergebnissen von MALDI- und Dialyse-Experimenten, kann man sicher annehmen, dass IISBT in einer kombinierten kovalent-reversiblen Art und Weise an die SARS-CoV-Mpro bindet.SARS („severe acute respiratory syndrome”), a respiratory disease in humans, appeared in November 2002 for the first time. The causative agent of this disease is the SARS-associated coronavirus. Its replication machinery is maintained by the catalytic activity of a cysteine protease, named SARS coronavirus main protease (SARS-CoV-Mpro) that processes the virus derived polyproteins. Based on this key role the SARS-CoV-Mpro is an attractive target for the development of specific inhibitors against this protease thereby inhibiting the reproduction of the virus. In this work, the SARS-CoV-Mpro was expressed and purified by optimized methods. Through ESI-MS analysis an irreversible covalent interaction of various inhibitors was detected but also for the first time the binding of fragments of the inhibitors to the protease. Accordingly the SARS-CoV-Mpro inhibitors MH211A and UK-VI-1g displayed a covalent binding of the complete molecule to the enzyme monomer: surprisingly up to four molecules of MH211A and two molecules of UK-VI-1g respectively bound to one protease molecule. The interaction of UK-VI-1g with the protease was detected for two peptides ranging from amino acids 62 to 76 and 280 to 298 both of which are not located near the active site. In case of inhibitor Lit1 the 2,5-dinitro-4-trifluormethlphenyl-fragment and in TS48 the cinnamic acid-thioester-fragment binds covalently to each monomer in the dimeric enzyme. For the first time the SARS-CoV-Mpro was co-crystallized with specific inhibitors without cleaving the C-terminal His-tag. Three possible orientations of the inhibitor TS174 were identified in the active site of the protease. They could not be further resolved due to the weak electron density for the inhibitor. The iodoisatin derivative IISBT was co-crystallized with SARS-CoV-Mpro as well and a covalent binding mechanism of an isatin derivative to the SARS-CoV-Mpro was clearly shown for the first time in an X-ray structure. This structure then indicates that the previously published molecular docking studies demonstrating a noncovalent binding mode of IISBT and other isatin derivatives should be reconsidered. Based on an ESI-MS analysis and previous results of MALDI and dialysis experiments it is safe to assume that IISBT binds to the SARS-CoV-Mpro in a combined covalent reversible manner

    Numerical Analysis of the Combustion Dynamics of Passively Controlled Jets Issuing from Polygonal Nozzles

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    In the present work, the combustion of vitiated hydrogen jets issuing from differently shaped nozzles is modelled using the LES method. We investigate the impact of nozzle cross-sectional geometries (circular, square, triangular, hexagonal and hexagram) and the jet Reynolds numbers (Re= 18,000, 20,000 and 23,600) on the flame lift-off height, its structure, the locations of the temperature maxima and species distributions. The triangular nozzle yields the highest mixing rate and therefore the fastest decay of axial velocity and the fastest growth of the average temperature along the flame axis. It was found that for the largest Re, the zone of intense mixing and the reaction zone occur in distinct regions, while for the lower Re, these regions combine into an indistinguishable zone. Finally, it is shown that the lift-off height of the flames and the mean temperature field are non-linearly correlated with Re and strongly dependent on the nozzle shape

    Numerical Analysis of the Combustion Dynamics of Passively Controlled Jets Issuing from Polygonal Nozzles

    No full text
    In the present work, the combustion of vitiated hydrogen jets issuing from differently shaped nozzles is modelled using the LES method. We investigate the impact of nozzle cross-sectional geometries (circular, square, triangular, hexagonal and hexagram) and the jet Reynolds numbers (Re= 18,000, 20,000 and 23,600) on the flame lift-off height, its structure, the locations of the temperature maxima and species distributions. The triangular nozzle yields the highest mixing rate and therefore the fastest decay of axial velocity and the fastest growth of the average temperature along the flame axis. It was found that for the largest Re, the zone of intense mixing and the reaction zone occur in distinct regions, while for the lower Re, these regions combine into an indistinguishable zone. Finally, it is shown that the lift-off height of the flames and the mean temperature field are non-linearly correlated with Re and strongly dependent on the nozzle shape
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