Relevant bibliographies by topics / Several mechanisms

Academic literature on the topic 'Several mechanisms'

Author: Grafiati
Published: 10 December 2022
Last updated: 28 January 2023

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Journal articles on the topic "Several mechanisms"

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Sánchez-Viesca, Francisco, Martha Berros, and Reina Gómez. "Recent Advances in Several Organic Reaction Mechanisms." Modern Chemistry 7, no. 1 (2019): 18. http://dx.doi.org/10.11648/j.mc.20190701.14.

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Cho, Min, Jaeeun Kim, Jee Yeon Kim, Jeyong Yoon, and Jae-Hong Kim. "Mechanisms of Escherichia coli inactivation by several disinfectants." Water Research 44, no. 11 (June 2010): 3410–18. http://dx.doi.org/10.1016/j.watres.2010.03.017.

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Ebert, Franziska, André Weiss, Milena Bültemeyer, Ingrit Hamann, Andrea Hartwig, and Tanja Schwerdtle. "Arsenicals affect base excision repair by several mechanisms." Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis 715, no. 1-2 (October 2011): 32–41. http://dx.doi.org/10.1016/j.mrfmmm.2011.07.004.

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AI-Awad, Osama. "Acinetobacter baumannii using several mechanisms for carbapenem resistance." Burns 40, no. 5 (August 2014): 1052. http://dx.doi.org/10.1016/j.burns.2014.01.029.

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Jiang, Nan, and Jun Biao Liu. "Design and Analysis of Motion Mechanism Driven by Several IDMs in Parallel." Applied Mechanics and Materials 197 (September 2012): 55–59. http://dx.doi.org/10.4028/www.scientific.net/amm.197.55.

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As a kind of piezo actuator, impact drive mechanism (IDM) has advantages in precision machinery and instruments. Several IDMs are used in parallel to realize some motion mechanisms which have multi degrees of freedom (DOF). Two motion mechanisms are designed subsequently, and a spherical motor is designed and assembled in principle based on one of them. Experiment results reveal that this design method is feasible, but some problems exist, for example, vibration is serious. These problems should be solved in follow-up study.
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Odou, P., N. Ferrari, C. Barthelemy, S. Brique, M. Lhermitte, A. Vincent, C. Libersa, and H. Robert. "Grapefruit juice-nifedipine interaction: possible involvement of several mechanisms." Journal of Clinical Pharmacy and Therapeutics 30, no. 2 (April 2005): 153–58. http://dx.doi.org/10.1111/j.1365-2710.2004.00618.x.

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Rolland, Benjamin, Renaud Jardri, Ali Amad, Pierre Thomas, Olivier Cottencin, and Régis Bordet. "Pharmacology of Hallucinations: Several Mechanisms for One Single Symptom?" BioMed Research International 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/307106.

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Hallucinations are complex misperceptions, that principally occur in schizophrenia or after intoxication induced by three main classes of drugs: psychostimulants, psychedelics, and dissociative anesthetics. There are at least three different pharmacological ways to induce hallucinations: (1) activation of dopamine D2 receptors (D2Rs) with psychostimulants, (2) activation of serotonin 5HT2A receptors (HT2ARs) with psychedelics, and (3) blockage of glutamate NMDA receptors (NMDARs) with dissociative anesthetics. In schizophrenia, the relative importance of NMDAR and D2R in the occurrence of hallucinations is still debated. Slight clinical differences are observed for each etiology. Thus, we investigated whether the concept of hallucination is homogenous, both clinically and neurobiologically. A narrative review of the literature is proposed to synthesize how the main contributors in the field have approached and tried to solve these outstanding questions. While some authors prefer one explanatory mechanism, others have proposed more integrated theories based on the different pharmacological psychosis models. In this review, such theories are discussed and faced with the clinical data. In addition, the nosological aspects of hallucinations and psychosis are addressed. We suggest that if there may be common neurobiological pathways between the different pharmacological systems that are responsible for the hallucinations, there may also be unique properties of each system, which explains the clinical differences observed.
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Mrotzek, T., A. Hoffmann, and U. Martin. "Hardening mechanisms and recrystallization behaviour of several molybdenum alloys." International Journal of Refractory Metals and Hard Materials 24, no. 4 (July 2006): 298–305. http://dx.doi.org/10.1016/j.ijrmhm.2005.10.003.

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Korgin, N. A., and V. O. Korepanov. "Experimental and theoretical comparison of several resource allocation mechanisms." IFAC-PapersOnLine 50, no. 1 (July 2017): 15592–97. http://dx.doi.org/10.1016/j.ifacol.2017.08.1886.

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Li, Zhi Hui, Jun Ping Shi, and An Min Tang. "Research on Several Fracture Forms and Controlling Parameters of Ductile Materials." Advanced Materials Research 374-377 (October 2011): 770–74. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.770.

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The experimental procedures of mixed mode fracture of several ductile materials are investigated. The position and direction of crack initiation are determined according to a new method. The variations of fracture caused by different physical mechanisms are analyzed. Through studying the changing regularity of different fracture mechanisms, it is believed that the main ways of the fracture in ductile materials can be divided into three groups. They are traction fracture and two different types of shear fracture. Void nucleation, expansion and coalescing are the dominant mechanism of traction fracture. The formation and development of localized shear bands are the dominant mechanism of the two different types of shear fracture. Localized large plastic deformation will cause damage within the material. The fundamental factor, which causes the occurrence of fracture in the material, is a certain stress parameter at the dangerous point has reached the critical fracture value of the material. Based on those phenomena listed above, several fracture controlling parameters for different fracture forms have been discussed, and several new parameters, which affect various fracture forms, have been proposed.
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Dissertations / Theses on the topic "Several mechanisms"

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Wolf, Edward. "Impact damage mechanisms in several laminated material systems." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12823.

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Yau, Desmond. "Analysis of coupling, guiding and radiation mechanisms on several microwave structures /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16164.pdf.

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Seehamart, Kompichit. "Investigation of the diffusion mechanisms of several hydrocarbons in the Metal-Organic-Framework Zn(tbip)." Doctoral thesis, Universitätsbibliothek Leipzig, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-68125.

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Most of the computer simulations of molecules in Metal-Organic Frameworks (MOFs) to be found in the literature are done with rigid framework. But, Molecular Dynamics (MD) simulations of the self-diffusivity, Ds, of ethane within the one-dimensional 4.5 Å channels of the MOF type Zn(tbip)(H2 tbip = 5-tert-butyl isophthalic acid) presented in this work have shown not only quantitative, but also qualitative, differences in the Ds values for fixed and flexible lattices. Particularly, the dependence of Ds upon the concentration of molecules, c, is strongly influenced by the lattice flexibility. The reasons for this influence are investigated with the aid of probability density plots, free energy landscapes and barriers, along with a determination of the structural changes accompanying increasing c. It is found that for flexible lattices, the tighter, more constrained parts of the channels become wider at higher c; this allows more molecules to diffuse in the central region of the channels. The investigations for Zn(tbip) have been extended to three equimolar mixtures of ethane/ethane, CO2/ethane and CO2/methanol. The simulations take into account the lattice flexibility. The diffusional characteristics are discussed in relation to molecule properties and lattice geometry. The results show that Zn(tbip) may be a useful material for separating methane/ethane and CO2/ethane mixtures at low concentrations, and CO2/methanol mixtures at high concentrations. The temperature and concentration dependence of the self-diffusivity of propane diffusion in Zn(tbip) have been investigated as well by performing normal MD and hyper-MD with bias potential simulations. The obtained temperature dependence of the self-diffusivities is analyzed using an Arrhenius relationship, yielding the activation energy to be 9.53 kJ/mol and the pre-exponential factor to be 4.48×10-9 m2s-1. Using this hyper-MD method, interesting mechanisms of the propane molecules able to pass each other and exchange their sites in the channels can be observed. Because of mutual hindrance of propane molecules, the propane self-diffusivities decrease with increasing concentration.
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Gurevic, Ilya. "Studies on the hydride transfer and other aspects of several thymidylate synthase variants." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6586.

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The nucleotide 2'-deoxythymidine 5'-monophosphate (thymidylate, dTMP) is phosphorylated twice to become a substrate for DNA polymerases, which copy a cell’s genetic information in advance of cell division. The main route to dTMP is mediated by the enzyme thymidylate synthase (TSase) and goes through 2'-deoxyuridine 5'-monophosphate (dUMP); dUMP’s heterocyclic aromatic pyrimidine ring loses a proton from its C5 position and gains a methylene and a hydride from the other reactant, methylene tetrahydrofolate (MTHF). In general, intricate knowledge of an enzyme’s mechanism can yield insight that leads to the development of precision-targeted inhibitors tailored exactly to thymidylate synthase. In fact, even more careful targeting could be achievable: Although E. coli TSase has served as a model system, investigators have increasingly been directing their lines of inquiry toward human TSase. A general enzymatic catalytic cascade is complex, comprising substrate binding, the chemical steps and product release; typically, the product release step is rate-limiting. TSase, however, is partially rate-limited by the chemistry portion of the process. The enzymatic mechanism has been considered for decades, yet recently has undergone a reassessment. After substrate binding – for which there is strong evidence for preference to dUMP as the first ligand in the wild-type E. coli enzyme – the important events are methylene transfer from MTHF to dUMP, proton abstraction and hydride transfer. The last of these – hydride transfer – is irreversible and rate-limiting (to a large degree without Mg2+, and to a small but noticeable degree with Mg2+). The studies described here are aimed at three therapeutically relevant questions: (a) determining the extent of negative charge accumulation at the O4 position of the hydride transfer acceptor; (b) expanding knowledge of the differential properties of E. coli and human TSase; and (c) gaining insight into the molecular origin of the drug resistance seen in a clinically relevant human TSase mutant. The properties touched on in this work include steady-state kinetics; inhibition constants toward 5-fluoro dUMP, substrate binding sequence and the temperature dependency of intrinsic hydride transfer kinetic isotope effects (KIEs). Intrinsic KIEs are a specialized measurement that permits the investigator to examine a particular hydrogen transfer step in isolation; it is achieved by labeling the bond to hydrogen broken in the reaction with protium (1H, also written as H), deuterium (2H, also written as D) or tritium (3H, also written as T). The latter is radioactive. The reaction is conducted with a mixture of two hydrogen isotopes at a time, and the extent to which the heavier isotope is disfavored against reaction is assessed; this covers multiple steps. Heavier isotopes directly participating in a chemical step react slower both because of zero-point vibrational energies if a semi-classical view is taken and because of the mass-dependence of tunneling probabilities if a quantum-mechanical view is taken. Each of the two-way isotopic comparisons mentioned above furnishes an observed KIE for that competition between two isotopes. Mathematical combination of two isotopic comparisons cancels out the effect of isotopically insensitive steps and provides rich insight into the hydride transfer alone. The ultimate result is the ratio of rate constants for the isotopologues; this ratio’s magnitude and variation with temperature report on the compactness of the active site and its resistance to thermal fluctuation, respectively. Our results reveal a possible role for E. coli asparagine 177 (N177) in the hydride transfer transition state (TS) stabilization, as revealed by its disruption in the aspartate mutant, N177D. This disruption was found to be alleviated to a high extent when the substrate was changed to dCMP, consistent with the N177 stabilizing partial negative charge at the TS for hydride transfer. This has drug design implications. Our work on human TSase underscores slightly weaker substrate binding preference, insensitivity to Mg2+ and mild alteration of hydride transfer TS when compared with E. coli TSase. Finally, analysis of the Y33H mutant of human TSase – the affected residue being remote from the active site – indicated the drug resistance was because of a higher inhibition constant for 5F-dUMP and that the hydride transfer step is disrupted, with a wider variation among donor-acceptor distances (between the two carbons involved in the hydride transfer at the TS for that step). Other researchers’ crystallographic evidence reveals greater positional uncertainty for a set of active-site side chains in the E. coli equivalent mutant. In totality, the data available implicate enzyme motions as relevant to drug binding and to catalysis for human TSase. In summary, the research described herein enriches the understanding of several aspects of the behavior of multiple TSase variants – the overall performance as seen via steady-state kinetics; the pattern of substrate binding as seen with observed KIEs for the proton abstraction step; and the efficiency of active site preparation for hydride transfer as evidenced in the temperature dependency of intrinsic hydride transfer KIEs.
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Casalena, Lee. "Multimodal Nanoscale Characterization of Transformation and Deformation Mechanisms in Several Nickel Titanium Based Shape Memory Alloys." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1499568013015563.

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Seehamart, Kompichit [Verfasser], Jörg [Akademischer Betreuer] Kärger, and Berend [Akademischer Betreuer] Smit. "Investigation of the diffusion mechanisms of several hydrocarbons in the Metal-Organic-Framework Zn(tbip) / Kompichit Seehamart. Gutachter: Jörg Kärger ; Berend Smit. Betreuer: Jörg Kärger." Leipzig : Universitätsbibliothek Leipzig, 2011. http://d-nb.info/1020088958/34.

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Cawthorn, Christopher John. "Several applications of a model for dense granular flows." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/245044.

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This dissertation describes efforts to evaluate a recently proposed continuum model for the dense flow of dry granular materials (Jop, Forterre & Pouliquen, 2006, Nature, 441, 167-192). The model, based upon a generalisation of Coulomb sliding friction, is known to perform well when modelling certain simple free surface flows. We extend the application of this model to a wide range of flow configurations, beginning with six simple flows studied in detailed experiments (GDR MiDi, 2004, Eur. Phys. J. E, 14, 341-366). Two-dimensional shearing flows and problems of linear stability are also addressed. These examples are used to underpin a thorough discussion of the strengths and weaknesses of the model. In order to calculate the behaviour of granular material in more complicated configurations, it is necessary to undertake a numerical solution. We discuss several computational techniques appropriate to the model, with careful attention paid to the evolution of any shear-free regions that may arise. In addition, we develop a numerical scheme, based upon a marker-and-cell method, that is capable of modelling two-dimensional granular flow with a moving free surface. A detailed discussion of our unsuccessful attempt to construct a scheme based upon Lagrangian finite elements is presented in an appendix. We apply the marker-and-cell code to the key problem of granular slumping (Balmforth & Kerswell, 2005, J. Fluid Mech., 538, 399-428), which has hitherto resisted explanation by modelling approaches based on various reduced (shallow water) models. With our numerical scheme, we are able to lift the assumptions required for other models, and make predictions in good qualitative agreement with the experimental data. An additional chapter describes the largely unrelated problem of contact between two objects separated by a viscous fluid. Although classical lubrication theory suggests that two locally smooth objects converging under gravity will make contact only after infinite time, we discuss several physical effects that may promote contact in finite time. Detailed calculations are presented to illustrate how the presence of a sharp asperity can modify the approach to contact.
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Jones, Christopher David Stanford. "On the cross-sectional form of the patella in several primates." Title page, table of contents and abstract only, 2003. http://web4.library.adelaide.edu.au/theses/09PH/09phj764.pdf.

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Kong, Dali. "Analytical and numerical studies of several fluid mechanical problems." Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/3651.

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In this thesis, three parts, each with several chapters, are respectively devoted to hydrostatic, viscous and inertial fluids theories and applications. In the hydrostatics part, the classical Maclaurin spheroids theory is generalized, for the first time, to a more realistic multi-layer model, which enables the studies of some gravity problems and direct numerical simulations of flows in fast rotating spheroidal cavities. As an application of the figure theory, the zonal flow in the deep atmosphere of Jupiter is investigated for a better understanding of the Jovian gravity field. High viscosity flows, for example Stokes flows, occur in a lot of processes involving low-speed motions in fluids. Microorganism swimming is such typical a case. A fully three dimensional analytic solution of incompressible Stokes equation is derived in the exterior domain of an arbitrarily translating and rotating prolate spheroid, which models a large family of microorganisms such as cocci bacteria. The solution is then applied to the magnetotactic bacteria swimming problem and good consistency has been found between theoretical predictions and laboratory observations of the moving patterns of such bacteria under magnetic fields. In the analysis of dynamics of planetary fluid systems, which are featured by fast rotation and very small viscosity effects, three dimensional fully nonlinear numerical simulations of Navier-Stokes equations play important roles. A precession driven flow in a rotating channel is studied by the combination of asymptotic analyses and fully numerical simulations. Various results of laminar and turbulent flows are thereby presented. Computational fluid dynamics requires massive computing capability. To make full use of the power of modern high performance computing facilities, a C++ finite-element analysis code is under development based on PETSc platform. The code and data structures will be elaborated, along with the presentations of some preliminary results.
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Nunes, da Silva Ana Sofia. "Characterization of the molecular mechanisms involved in severe malaria pathogenesis." Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC065.

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L'importante virulence de P. Falciparum a été reliée à la capacité du parasite à adhérer aux cellules endothéliales de la microvasculature ou aux syncytiotrophoblastes placentaires. La séquestration de globules rouges infectés dans différents organes conduit à l'apparition des symptômes cliniques de la maladie. Les protéines variables PfEMP1, exprimées à la surface des hématies parasitées, sont les ligands parasitaires majeurs responsables de la cytoadhérence. PfEMP1-VAR2CSA est le candidat vaccinal le plus prometteur pour lutter contre le paludisme gestationnel. Afin de mieux caractériser les interactions entre la protéine VAR2CSA et son ligand naturel, la CSA, nous avons généré des VEIH contre VAR2CSA. Nous avons obtenu 19 VHHs, en grand partie dirigés contre le domaine DBLIX. Quatre VHHs contre DBL1X étaient capable d'inhiber les interactions entre les hématies parasitées et la CSA, montrant que le domaine DBL1X fait partie ou est localisé très proche du site de liaison au récepteur. Le paludisme sévère a été associé la séquestration des hématies parasitées, exprimant les cassettes de domaines DC8 ou DC13, au récepteur endothélial de la protéine C (EPCR) exprimé à l'endothélium vasculaire. Dans cette étude nous avons montré que la cassette DC8 de IT4VAR19 adhère avec une plus grande affinité à l'EPCR et HBEC5i que le domaine CIDRŒ I. 1 seul. Nous avons observé que, même si IT4VAR19 est le variant préférentiellement exprimé par la souche IT4 après sélection à l'EPCR, l'immunité humorale contre IT4VAR19-DC8 cassette et IT4VAR19-CIDR n'est pas stimulé pendant un épisode de paludisme pédiatrique sévère au Bénin. En conclusion, ce projet de thèse permet de mieux comprendre les interactions moléculaires impliquées dans l'adhérence des globules rouges parasités aux cellules endothéliales de l'hôte et contribuera à l'élaboration d'approches vaccinales ou thérapeutiques visant à protéger les patients des symptômes cliniques du paludisme sévère
Sequestration of infected erythrocytes (IEs) is the prime mediator of disease and is mediated by members of the highly diverse PfEMP1. The aim of this thesis was to characterize the molecular mechanisms associated to pregnancy associated malaria (PAM) and severe malaria, in order to design new intervention strategies to protect patients against severe malaria clinical symptoms. PfEMP 1 -VAR2CSA stands today as the leading vaccine candidate aiming to protect future pregnant women against the severe clinical outcomes of PAM. In order to better characterize the interactions between PfEMPI-VAR2CSA and its receptor CSA, we generated VAR2CSA specific nanobodies. Following immunization of a Ilama with the full-length VAR2CSA recombinant protein, we obtained 19 nanobodies, mainly targeting the DBL1X. Four nanobodies targeting DBL1X reproducibly inhibited CSA adhesion of erythrocytes infected with the homologous NF54-CSA parasite strain, providing evidences that DBL1X domain is part or close to the CSA binding site. Severe malaria was recently associated with binding of IEs, expressing domain cassettes DC8 and DC13, to Endothelial Protein C Receptor (EPCR) pr'sent in the host endothelium. In this study we demonstrated that the IT4VAR19-DC8 binds to EPCR with a greater affinity than the CIDRa1. L domain alone and also the binding to EPCR-expressing endothélial cell line (HBEC5i) is more pronounced. We observed that although IT4VAR19 is the preferentially selected EPCR-binding variant from IT4 strain, the humoral immunity against the EPCR binding IT4VAR19-DC8 cassette or the CIDRa1. 1 domain is not boosted during a severe pediatric malaria episode in Benin. In conclusion, this thesis provide new insights on the molecular mechanisms underlying the binding of P. Falciparum infected erythrocytes to the host endothelium that will help in the development of anti-adhesive strategies to protect patients against severe malaria clinical outcomes
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Books on the topic "Several mechanisms"

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Gorgidze, Ivane, and Tamar Lominadze. Several problems of applied mathematics and mechanics. Hauppauge, N.Y: Nova Science Publishers, 2011.

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The Slavicization of the Russian North: Mechanisms and chronology = Die Slavisierung Nordrusslands : Mechanismen und Chronologie = Slavi︠a︡nizat︠s︡ii︠a︡ russkogo severa : mekhanizmy i khronologii︠a︡. Helsinki: Department of Slavonic and Baltic Languages and Literatures, 2006.

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Leray, Jean. Selected papers =: Oeuvres scientifiques. Edited by Malliavin Paul 1925-. Berlin: Springer, 1998.

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Leray, Jean. Selected papers =: Oeuvres scientifiques. Berlin: Springer, 1998.

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Leray, Jean. Selected papers =: Oeuvres scientifiques. Berlin: Springer, 1998.

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Hofmeister, R. Jon. Slope failures in Oregon: GIS inventory for three 1996/97 storm events. [Portland, Or.]: Dept. of Geology and Mineral Industries, 2000.

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Joyce, J. A. The effect of electric discharge machined notches on the fracture toughness of several structural alloys. Washington, DC: Division of Engineering, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 1993.

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Merkur'ev, S. P. Quantum scattering theory for several particle systems. Dordrecht: Kluwer Academic Publishers, 1993.

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Liwenga, Emma T. Household food insecurity and coping mechanisms in severely eroded areas: The case of Kondoa eroded area, Tanzania. [Dar es Salaam]: Institute of Resource Assessment, University of Dar es Salaam, 1997.

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National Aeronautics and Space Administration (NASA) Staff. Tribological Properties of Several Silahydrocarbons for Use in Space Mechanisms. Independently Published, 2018.

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Book chapters on the topic "Several mechanisms"

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Hahn, Hubert. "Spatial mechanisms with several rigid bodies." In Rigid Body Dynamics of Mechanisms, 471–622. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-662-09769-4_8.

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Ohtsuki, Iwao, Sachio Morimoto, and Fumi Takahashi-Yanaga. "Several Aspects of Calcium Regulator Mechanisms Linked to Troponin." In Advances in Experimental Medicine and Biology, 221–29. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4419-9029-7_21.

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Polyánka, H., L. Makrai, T. Ertli, and E. Lehoczki. "Comparison of Sensitivity of Triazine-Resistant and Susceptible Biotypes of Several Weeds to UV-B Exposure." In Photosynthesis: Mechanisms and Effects, 2397–400. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_563.

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Planat, Valérie, Jean-Marc Lanau, Michel Record, and Hugues Chap. "Phospholipase D Regulation in Relationship with Several Protein Kinases Activation in Human Neutrophil." In Signalling Mechanisms — from Transcription Factors to Oxidative Stress, 49–55. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-79675-3_5.

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Treiber, Martin, and Arne Kesting. "Modelling and Simulating Several Time-Delay Mechanisms in Human and Automated Driving." In Traffic and Granular Flow ’07, 413–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-77074-9_45.

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Lynall, Gregory. "Meditations and Mechanisms: Swift and Robert Boyle’s Occasional Reflections upon Several Subjects." In Swift and Science, 17–49. London: Palgrave Macmillan UK, 2012. http://dx.doi.org/10.1057/9781137016966_2.

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Sung, Tien-Wen, Xiaohui Hu, and Haiyan Ou. "Review of Several Address Assignment Mechanisms for Distributed Smart Meter Deployment in Smart Grid." In Advances in Intelligent Systems and Computing, 171–78. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-58669-0_15.

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Von Huene, Roland. "Some Implications Regarding Tectonic Mechanisms from the Structural Diversity along Several Modern Convergent Margins." In Formation of Active Ocean Margins, 179–91. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4720-7_8.

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Zetzsche, Georg. "Recent Advances on Reachability Problems for Valence Systems (Invited Talk)." In Lecture Notes in Computer Science, 52–65. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-89716-1_4.

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AbstractValence systems are an abstract model of computation that consists of a finite-state control and some storage mechanism. In contrast to traditional models, the storage mechanism is not fixed, but given as a parameter. This allows us to precisely state questions like: For which storage mechanisms is the reachability problem decidable?This survey reports on recent results that aim to understand the impact of the storage mechanism on decidability and complexity of several variants of the reachability problem. The considered problems are configuration reachability, model-checking first-order logic with reachability, and reachability under bounded context switching and scope-boundedness.
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Sladič, Jorg. "The Lessons of Airfreight Cartel: Mechanisms of Coordination of Parallel Collective Lawsuits in Several Jurisdictions?" In Class Actions in Europe, 249–85. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-73036-9_11.

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Conference papers on the topic "Several mechanisms"

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Abdulov, Alexander, and Alexander Abramenkov. "Several movement rules for mobile robots in counter flows." In 2017 Dynamics of Systems, Mechanisms and Machines (Dynamics). IEEE, 2017. http://dx.doi.org/10.1109/dynamics.2017.8239423.

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Gecim, Burak, and Madhusudan Raghavan. "Simulation and Test Results for Several Variable-Valve-Actuation Mechanisms." In SAE World Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2009. http://dx.doi.org/10.4271/2009-01-0229.

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Borthwick, Ian S., Alastair Clark, Kenneth W. D. Ledingham, and Ravi P. Singhal. "The characteristics of Q-switched laser ablation for several elements from a low alloy steel." In Laser ablation: mechanisms and applications—II. AIP, 1993. http://dx.doi.org/10.1063/1.44899.

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Axelrod, A. "On crosstalk mechanisms in cables composed of several unshielded twisted pairs." In 2003 IEEE International Symposium on Electromagnetic Compatibility, 2003. EMC '03. IEEE, 2003. http://dx.doi.org/10.1109/icsmc2.2003.1429086.

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Aroussi, A., A. Hassan, B. R. Clayton, and B. S. Abdulnour. "Comparison of Performance between Several Vehicle Windshield Defrosting and Demisting Mechanisms." In SAE 2001 World Congress. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2001. http://dx.doi.org/10.4271/2001-01-0582.

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Hetrick, Joel A., and Sridhar Kota. "Size and Shape Optimization of Compliant Mechanisms: An Efficiency Formulation." In ASME 1998 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/detc98/mech-5943.

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Abstract Compliant mechanisms are jointless mechanical devices that take advantage of elastic deformation to achieve a force or motion transformation. A milestone toward systematic design of compliant mechanisms has been the development of topology optimization techniques. The next logical step is to incorporate size and shape optimization to identify the exact dimensional form of the mechanism. A new objective formulation based on maximizing the mechanical efficiency of a compliant mechanism is developed in order to perform the size and shape optimization. An advantage of this formulation is that precise control over the mechanism’s mechanical or geometric advantage can be enforced during optimization. Finite element beam models are used to perform dimensional synthesis of planar compliant mechanisms. This technique allows stress constraints to limit the maximum stress in the mechanism which improves the mechanism’s durability and flexibility. Resulting optimized mechanisms exhibit efficient mechanical transmission and meet kinematic and stress requirements. Several examples are given to demonstrate the effectiveness of the optimization procedure.
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Luck, Kurt, and Karl-Heinz Modler. "Burmester-Theory for Band-Mechanisms." In ASME 1992 Design Technical Conferences. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/detc1992-0277.

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Abstract A band-mechanism includes inter alia a flexible band and a disk-profile. Such a mechanism can excellent be used for path-generation, better than a four-bar-linkage. Also several plane-positions additionally can be realized. This paper investigates the synthesis of four-bar-band-mechanisms by using the complex vector-algebra. Several technical tasks demonstrate the flexible application of such mechanisms. This tasks are formulated analogous to the wellknown BURMESTER-THEORY, but with higher claims and the solution is done by analytical methods. Further it is demonstrated that a four-bar-linkage is a special case of a four-bar-band-mechanism.
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Ding, Huafeng, Jing Zhao, and Zhen Huang. "The Establishment of Novel Structure Representation Models for Several Kinds of Mechanisms." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-86074.

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This paper attempts to establish the unified topological models and corresponding mathematical representations for planar simple joint, multiple joint and geared (cam) kinematic chains. First, the conventional topological representation models of kinematic chains are introduced. Then new topological models of multiple joint and geared (cam) kinematic chains, which are derived from the topological graph of simple joint kinematic chains, are presented. The characteristics of the new topological graphs and their associations with the topological graph of simple joint kinematic chains are also addressed. The most important merit of the new topological graphs is that it makes it much easier to do unified structure synthesis and further establish conceptual design platform for various planar mechanisms of these kinds.
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Chew, Meng-Sang, Richard W. Longman, and Minh Q. Phan. "Intelligent Mechanisms." In ASME 2004 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/detc2004-57553.

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An intelligent mechanism is a traditional mechanism that incorporates within it, elements of intelligence both at the design stage. Thepurpose is to increase the operational envelop of the original meachanism so that it can now exhibit some from of learning, adapting, or responding to changes in the environment or new operating conditions. Since mechanisms are usually designed for repetitive motions, the application of intelligence that makes specific use of repetitive characteristics will markedly improve the functionality of the mechanisms. This is particularly true if the mechanisms have been incorporated with such intelligence at the early stages of design. This article develops the concept of an intelligent mechanism through the application of Iterative Learning Control and Repetitive Control methodologies to several traditional mechanisms. These range from the simple slider-crank and four-bar linkage to timing belts.
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Opdahl, Patrick G., Brian D. Jensen, and Larry L. Howell. "An Investigation Into Compliant Bistable Mechanisms." In ASME 1998 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/detc98/mech-5914.

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Abstract This paper proposes a new class of bistable mechanisms: compliant bistable mechanisms. These mechanisms gain their bistable behavior from the energy stored in the flexible segments which deflect to allow mechanism motion. This approach integrates desired mechanism motion and energy storage to create bistable mechanisms with dramatically reduced part count compared to traditional mechanisms incorporating rigid links, joints, and springs. This paper briefly reviews bistable mechanism theory, introduces some additional bistable mechanism characteristics, and integrates this theory with compliant mechanism theory. The resulting theory of bistable compliant mechanisms is validated by measuring the force and motion characteristics of several test mechanisms and comparing them to predicted values.
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Reports on the topic "Several mechanisms"

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Mittelsteadt, Matthew. AI Verification: Mechanisms to Ensure AI Arms Control Compliance. Center for Security and Emerging Technology, February 2021. http://dx.doi.org/10.51593/20190020.

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The rapid integration of artificial intelligence into military systems raises critical questions of ethics, design and safety. While many states and organizations have called for some form of “AI arms control,” few have discussed the technical details of verifying countries’ compliance with these regulations. This brief offers a starting point, defining the goals of “AI verification” and proposing several mechanisms to support arms inspections and continuous verification.
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Lever, James, Emily Asenath-Smith, Susan Taylor, and Austin Lines. Assessing the mechanisms thought to govern ice and snow friction and their interplay with substrate brittle behavior. Engineer Research and Development Center (U.S.), December 2021. http://dx.doi.org/10.21079/1168142742.

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Sliding friction on ice and snow is characteristically low at temperatures common on Earth’s surface. This slipperiness underlies efficient sleds, winter sports, and the need for specialized tires. Friction can also play micro-mechanical role affecting ice compressive and crushing strengths. Researchers have proposed several mechanisms thought to govern ice and snow friction, but directly validating the underlying mechanics has been difficult. This may be changing, as instruments capable of micro-scale measurements and imaging are now being brought to bear on friction studies. Nevertheless, given the broad regimes of practical interest (interaction length, temperature, speed, pressure, slider properties, etc.), it may be unrealistic to expect that a single mechanism accounts for why ice and snow are slippery. Because bulk ice, and the ice grains that constitute snow, are solids near their melting point at terrestrial temperatures, most research has focused on whether a lubricating water film forms at the interface with a slider. However, ice is extremely brittle, and dry-contact abrasion and wear at the front of sliders could prevent or delay a transition to lubricated contact. Also, water is a poor lubricant, and lubricating films thick enough to separate surface asperities may not form for many systems of interest. This article aims to assess our knowledge of the mechanics underlying ice and snow friction.
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Plourde, A. P., and J. F. Cassidy. Mapping tectonic stress at subduction zones with earthquake focal mechanisms: application to Cascadia, Japan, Nankai, Mexico, and northern Chile. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/330943.

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Earthquake focal mechanisms have contributed substantially to our understanding of modern tectonic stress regimes, perhaps more than any other data source. Studies generally group focal mechanisms by epicentral location to examine variations in stress across a region. However, stress variations with depth have rarely been considered, either due to data limitations or because they were believed to be negligible. This study presents 3D grids of tectonic stress tensors using existing focal mechanism catalogs from several subduction zones, including Cascadia, Japan, Nankai, Mexico, and northern Chile. We bin data into 50 x 50 x 10 km cells (north, east, vertical), with 50% overlap in all three directions. This resulted in 181380 stress inversions, with 90% of these in Japan (including Nankai). To the best of our knowledge, this is the first examination of stress changes with depth in several of these regions. The resulting maps and cross-sections of stress can help distinguish locked and creeping segments of the plate interface. Similarly, by dividing the focal mechanism catalog in northern Japan into those before and those >6 months after the 2011 Mw 9.1 Tohoku-Oki earthquake, we are able to produce detailed 3D maps of stress rotation, which is close to 90° near the areas of highest slip. These results could inform geodynamic rupture models of future megathrust earthquakes in order to more accurately estimate slip, shaking, and seismic hazard. Southern Cascadia and Nankai appear to have sharp stress discontinuities at ~20 km depth, and northern Cascadia may have a similar discontinuity at ~30 km depth. These stress boundaries may relate to rheological discontinuities in the forearc, and may help us unravel how forearc composition influences subduction zone behaviour and seismic hazard.
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Lehtimaki, Susanna, Aisling Reidy, Kassim Nishtar, Sara Darehschori, Andrew Painter, and Nina Schwalbe. Independent Review and Investigation Mechanisms to Prevent Future Pandemics: A Proposed Way Forward. United Nations University International Institute for Global Health, April 2021. http://dx.doi.org/10.37941/rr/2021/1.

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The COVID-19 pandemic has created enormous challenges for national economies, livelihoods, and public services, including health systems. In January 2021, the World Health Organization proposed an international treaty on pandemics to strengthen the political commitment towards global pandemic preparedness, control, and response. The plan is to present a draft treaty to the World Health Assembly in May 2021. To inform the design of a support system for this treaty, we explored existing mechanisms for periodic reviews conducted either by peers or an external group as well as mechanisms for in-country investigations, conducted with or without country consent. Based on our review, we summarized key design principles requisite for review and investigation mechanisms and explain how these could be applied to pandemics preparedness, control, and response in global health. While there is no single global mechanism that could serve as a model in its own right, there is potential to combine aspects of existing mechanisms. A Universal Periodic Review design based on the model of human rights treaties with independent experts as the authorized monitoring body, if made obligatory, could support compliance with a new pandemic treaty. In terms of on-site investigations, the model by the Committee on Prevention of Torture could lend itself to treaty monitoring and outbreak investigations on short notice or unannounced. These mechanisms need to be put in place in accordance with several core interlinked design principles: compliance; accountability; independence; transparency and data sharing; speed; emphasis on capabilities; and incentives. The World Health Organization can incentivize and complement these efforts. It has an essential role in providing countries with technical support and tools to strengthen emergency preparedness and response capacities, including technical support for creating surveillance structures, integrating non-traditional data sources, creating data governance and data sharing standards, and conducting regular monitoring and assessment of preparedness and response capacities.
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Samach, Alon, Douglas Cook, and Jaime Kigel. Molecular mechanisms of plant reproductive adaptation to aridity gradients. United States Department of Agriculture, January 2008. http://dx.doi.org/10.32747/2008.7696513.bard.

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Annual plants have developed a range of different mechanisms to avoid flowering (exposure of reproductive organs to the environment) under adverse environmental conditions. Seasonal environmental events such as gradual changes in day length and temperature affect the timing of transition to flowering in many annual and perennial plants. Research in Arabidopsis and additional species suggest that some environmental signals converge on transcriptional regulation of common floral integrators such as FLOWERING LOCUS T (FT). Here we studied environmental induction of flowering in the model legume Medicago truncatula. Similarly to Arabidopsis, the transition to flowering in M. truncatula is hastened by long photoperiods and long periods of vernalization (4°C for 2-3 weeks). Ecotypes collected in Israel retain a vernalization response even though winter temperatures are way above 4°C. Here we show that this species is also highly responsive (flowers earlier) to mild ambient temperatures up to 19°C simulating winter conditions in its natural habitat. Physiological experiments allowed us to time the transition to flowering due to low temperatures, and to compare it to vernalization. We have made use of natural variation, and induced mutants to identify key genes involved in this process, and we provide here data suggesting that an FT gene in M.truncatula is transcriptionally regulated by different environmental cues. Flowering time was found to be correlated with MtFTA and MtFTB expression levels. Mutation in the MtFTA gene showed a late flowering phenotype, while over-expressing MtFTA in Arabidopsis complemented the ft- phenotype. We found that combination of 4°C and 12°C resulted in a synergistic increase in MtFTB expression, while combining 4°C and long photoperiods caused a synergistic increase in MtFTA expression. These results suggest that the two vernalization temperatures work through distinct mechanisms. The early flowering kalil mutant expressed higher levels of MtFTA and not MtFTB suggesting that the KALIL protein represses MtFTA specifically. The desert ecotype Sde Boker flowers earlier in response to short treatments of 8-12oc vernalization and expresses higher levels of MtFTA. This suggests a possible mechanism this desert ecotype developed to flower as fast as possible and finish its growth cycle before the dry period. MtFTA and FT expression are induced by common environmental cues in each species, and expression is repressed under short days. Replacing FT with the MtFTA gene (including regulatory elements) caused high MtFTA expression and early flowering under short days suggesting that the mechanism used to repress flowering under short days has diversified between the two species.The circadian regulated gene, GIGANTEA (GI) encodes a unique protein in Arabidopsis that is involved in flowering mechanism. In this research we characterized how the expression of the M.truncatula GI ortholog is regulated by light and temperature in comparison to its regulation in Arabidopsis. In Arabidopsis GI was found to be involved in temperature compensation to the clock. In addition, GI was found to be involved in mediating the effect of temperature on flowering time. We tested the influence of cold temperature on the MtGI gene in M.truncatula and found correlation between MtGI levels and extended periods of 12°C treatment. MtGI elevation that was found mostly after plants were removed from the cold influence preceded the induction of MtFT expression. This data suggests that MtGI might be involved in 12°C cold perception with respect to flowering in M.truncatula. GI seems to integrate diverse environmental inputs and translates them to the proper physiological and developmental outputs, acting through several different pathways. These research enabled to correlate between temperature and circadian clock in M.truncatula and achieved a better understanding of the flowering mechanism of this species.
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Ali, Usman, Mamoru Kikumoto, Matteo Ciantia, and Ying Cui. Direct observation of particle kinematics in biaxial shearing test. University of Dundee, December 2021. http://dx.doi.org/10.20933/100001233.

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Biaxial shearing tests on dual-sized, 2d particle assemblies are conducted at several confining pressures. The effect of particle angularity, an important mesoscale shape descriptor, is investigated at the macro and micro levels. Macroscopically, it is observed that assemblies composed of angular particles exhibit higher strengths and dilations. The difference observed in bulk behavior due to particle angularity can be explained reasonably by considering particle-level mechanisms. A novel 2D image analysis technique is employed to estimate particle kinematics. Particle rotation results to be a key mechanism strongly influenced by particle shape determining the overall granular behavior. Unlike circular particles, angular ones are more resistant to rotations due to stronger interlocking and consequently exhibit higher strengths.
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Eyal, Yoram, and Sheila McCormick. Molecular Mechanisms of Pollen-Pistil Interactions in Interspecific Crossing Barriers in the Tomato Family. United States Department of Agriculture, May 2000. http://dx.doi.org/10.32747/2000.7573076.bard.

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During the evolutionary process of speciation in plants, naturally occurring barriers to reproduction have developed that affect the transfer of genes within and between related species. These barriers can occur at several different levels beginning with pollination-barriers and ending with hybrid-breakdown. The interaction between pollen and pistils presents one of the major barriers to intra- and inter-specific crosses and is the focus of this research project. Our long-term goal in this research proposal was defined to resolve questions on recognition and communication during pollen-pistil interactions in the extended tomato family. In this context, this work was initiated and planned to study the potential involvement of tomato pollen-specific receptor-like kinases (RLK's) in the interaction between pollen and pistils. By special permission from BARD the objectives of this research were extended to include studies on pollen-pistil interactions and pollination barriers in horticultural crops with an emphasis on citrus. Functional characterization of 2 pollen-specific RLK's from tomato was carried out. The data shows that both encode functional kinases that were active as recombinant proteins. One of the kinases was shown to accumulate mainly after pollen germination and to be phosphorylated in-vitro in pollen membranes as well as in-vivo. The presence of style extract resulted in dephosphorylation of the RLK, although no species specificity was observed. This data implies a role for at least one RLK in pollination events following pollen germination. However, a transgenic plant analysis of the RLK's comprising overexpression, dominant-negative and anti-sense constructs failed to provide answers on their role in pollination. While genetic effects on some of the plants were observed in both the Israeli and American labs, no clear functional answers were obtained. An alternative approach to addressing function was pursued by screening for an artificial ligand for the receptor domain using a peptide phage display library. An enriched peptide sequence was obtained and will be used to design a peptide-ligand to be tested for its effect o pollen germination and tube growth. Self-incompatibility (SI) in citrus was studied on 3 varieties of pummelo. SI was observed using fluorescence microscopy in each of the 3 varieties and compatibility relations between varieties was determined. An initial screen for an S-RNase SI mechanism yielded only a cDNA homologous to the group of S-like RNases, suggesting that SI results from an as yet unknown mechanism. 2D gel electrophoresis was applied to compare pollen and style profiles of different compatibility groups. A "polymorphic" protein band from style extracts was observed, isolated and micro-sequenced. Degenerate primers designed based on the peptide sequence date will be used to isolate the relevant genes i order to study their potential involvement in SI. A study on SI in the apple cultivar Top red was initiated. SI was found, as previously shown, to be complete thus requiring a compatible pollinator variety. A new S-RNase allele was discovered fro Top red styles and was found to be highly homologous to pear S-RNases, suggesting that evolution of these genes pre-dated speciation into apples and pears but not to other Rosaceae species. The new allele provides molecular-genetic tools to determine potential pollinators for the variety Top red as well as a tool to break-down SI in this important variety.
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Or, Etti, David Galbraith, and Anne Fennell. Exploring mechanisms involved in grape bud dormancy: Large-scale analysis of expression reprogramming following controlled dormancy induction and dormancy release. United States Department of Agriculture, December 2002. http://dx.doi.org/10.32747/2002.7587232.bard.

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The timing of dormancy induction and release is very important to the economic production of table grape. Advances in manipulation of dormancy induction and dormancy release are dependent on the establishment of a comprehensive understanding of biological mechanisms involved in bud dormancy. To gain insight into these mechanisms we initiated the research that had two main objectives: A. Analyzing the expression profiles of large subsets of genes, following controlled dormancy induction and dormancy release, and assessing the role of known metabolic pathways, known regulatory genes and novel sequences involved in these processes B. Comparing expression profiles following the perception of various artificial as well as natural signals known to induce dormancy release, and searching for gene showing similar expression patterns, as candidates for further study of pathways having potential to play a central role in dormancy release. We first created targeted EST collections from V. vinifera and V. riparia mature buds. Clones were randomly selected from cDNA libraries prepared following controlled dormancy release and controlled dormancy induction and from respective controls. The entire collection (7920 vinifera and 1194 riparia clones) was sequenced and subjected to bioinformatics analysis, including clustering, annotations and GO classifications. PCR products from the entire collection were used for printing of cDNA microarrays. Bud tissue in general, and the dormant bud in particular, are under-represented within the grape EST database. Accordingly, 59% of the our vinifera EST collection, composed of 5516 unigenes, are not included within the current Vitis TIGR collection and about 22% of these transcripts bear no resemblance to any known plant transcript, corroborating the current need for our targeted EST collection and the bud specific cDNA array. Analysis of the V. riparia sequences yielded 814 unigenes, of which 140 are unique (keilin et al., manuscript, Appendix B). Results from computational expression profiling of the vinifera collection suggest that oxidative stress, calcium signaling, intracellular vesicle trafficking and anaerobic mode of carbohydrate metabolism play a role in the regulation and execution of grape-bud dormancy release. A comprehensive analysis confirmed the induction of transcription from several calcium–signaling related genes following HC treatment, and detected an inhibiting effect of calcium channel blocker and calcium chelator on HC-induced and chilling-induced bud break. It also detected the existence of HC-induced and calcium dependent protein phosphorylation activity. These data suggest, for the first time, that calcium signaling is involved in the mechanism of dormancy release (Pang et al., in preparation). We compared the effects of heat shock (HS) to those detected in buds following HC application and found that HS lead to earlier and higher bud break. We also demonstrated similar temporary reduction in catalase expression and temporary induction of ascorbate peroxidase, glutathione reductase, thioredoxin and glutathione S transferase expression following both treatments. These findings further support the assumption that temporary oxidative stress is part of the mechanism leading to bud break. The temporary induction of sucrose syntase, pyruvate decarboxylase and alcohol dehydrogenase indicate that temporary respiratory stress is developed and suggest that mitochondrial function may be of central importance for that mechanism. These finding, suggesting triggering of identical mechanisms by HS and HC, justified the comparison of expression profiles of HC and HS treated buds, as a tool for the identification of pathways with a central role in dormancy release (Halaly et al., in preparation). RNA samples from buds treated with HS, HC and water were hybridized with the cDNA arrays in an interconnected loop design. Differentially expressed genes from the were selected using R-language package from Bioconductor project called LIMMA and clones showing a significant change following both HS and HC treatments, compared to control, were selected for further analysis. A total of 1541 clones show significant induction, of which 37% have no hit or unknown function and the rest represent 661 genes with identified function. Similarly, out of 1452 clones showing significant reduction, only 53% of the clones have identified function and they represent 573 genes. The 661 induced genes are involved in 445 different molecular functions. About 90% of those functions were classified to 20 categories based on careful survey of the literature. Among other things, it appears that carbohydrate metabolism and mitochondrial function may be of central importance in the mechanism of dormancy release and studies in this direction are ongoing. Analysis of the reduced function is ongoing (Appendix A). A second set of hybridizations was carried out with RNA samples from buds exposed to short photoperiod, leading to induction of bud dormancy, and long photoperiod treatment, as control. Analysis indicated that 42 genes were significant difference between LD and SD and 11 of these were unique.
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Sionov, Edward, Nancy Keller, and Shiri Barad-Kotler. Mechanisms governing the global regulation of mycotoxin production and pathogenicity by Penicillium expansum in postharvest fruits. United States Department of Agriculture, January 2017. http://dx.doi.org/10.32747/2017.7604292.bard.

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The original objectives of the study, as defined in the approved proposal, are: To characterize the relationship of CreA and LaeA in regulation of P T production To understand how PacC modulates P. expansumpathogenicity on apples To examine if other secondary metabolites are involved in virulence or P. expansumfitness To identify the signaling pathways leading to PAT synthesis Penicilliumexpansum, the causal agent of blue mould rot, is a critical health concern because of the production of the mycotoxinpatulin (PAT) in colonized apple fruit tissue. Although PAT is produced by many Penicilliumspecies, the factors activating its biosynthesis were not clear. This research focused on host and fungal mechanisms of activation of LaeA (the global regulator of secondary metabolism), PacC (the global pH modulator) and CreA (the global carbon catabolite regulator) on PAT synthesis with intention to establish P. expansumas the model system for understanding mycotoxin synthesis in fruits. The overall goal of this proposal is to identify critical host and pathogen factors that mechanistically modulate P. expansumgenes and pathways to control activation of PAT production and virulence in host. Several fungal factors have been correlated with disease development in apples, including the production of PAT, acidification of apple tissue by the fungus, sugar content and the global regulator of secondary metabolism and development, LaeA. An increase in sucrose molarity in the culture medium from 15 to 175 mM negatively regulated laeAexpression and PAT accumulation, but, conversely, increased creAexpression, leading to the hypothesis that CreA could be involved in P. expansumPAT biosynthesis and virulence, possibly through the negative regulation of LaeA. We found evidence for CreAtranscriptional regulation of laeA, but this was not correlated with PAT production either in vitro or in vivo, thus suggesting that CreA regulation of PAT is independent of LaeA. Our finding that sucrose, a key ingredient of apple fruit, regulates PAT synthesis, probably through suppression of laeAexpression, suggests a potential interaction between CreA and LaeA, which may offer control therapies for future study. We have also identified that in addition to PAT gene cluster, CreA regulates other secondary metabolite clusters, including citrinin, andrastin, roquefortine and communesins, during pathogenesis or during normal fungal growth. Following creation of P. expansumpacCknockout strain, we investigated the involvement of the global pH regulator PacC in fungal pathogenicity. We demonstrated that disruption of the pH signaling transcription factor PacC significantly decreased the virulence of P. expansumon deciduous fruits. This phenotype is associated with an impairment in fungal growth, decreased accumulation of gluconic acid and reduced synthesis of pectolytic enzymes. We showed that glucose oxidase- encoding gene, which is essential for gluconic acid production and acidification during fruit colonization, was significantly down regulated in the ΔPepacCmutant, suggesting that gox is PacC- responsive gene. We have provided evidence that deletion of goxgene in P. expansumled to a reduction in virulence toward apple fruits, further indicating that GOX is a virulence factor of P. expansum, and its expression is regulated by PacC. It is also clear from the present data that PacC in P. expansumis a key factor for the biosynthesis of secondary metabolites, such as PAT. On the basis of RNA-sequencing (RNA-seq) analysis and physiological experimentation, the P. expansumΔlaeA, ΔcreAand ΔpacCmutants were unable to successfully colonize apples for a multitude of potential mechanisms including, on the pathogen side, a decreased ability to produce proteolytic enzymes and to acidify the environment and impaired carbon/nitrogen metabolism and, on the host side, an increase in the oxidative defence pathways. Our study defines these global regulatory factors and their downstream signalling pathways as promising targets for the development of strategies to fight against this post-harvest pathogen.
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Brown Horowitz, Sigal, Eric L. Davis, and Axel Elling. Dissecting interactions between root-knot nematode effectors and lipid signaling involved in plant defense. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598167.bard.

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Root-knot nematodes, Meloidogynespp., are extremely destructive pathogens with a cosmopolitan distribution and a host range that affects most crops. Safety and environmental concerns related to the toxicity of nematicides along with a lack of natural resistance sources threaten most crops in Israel and the U.S. This emphasizes the need to identify genes and signal mechanisms that could provide novel nematode control tactics and resistance breeding targets. The sedentary root-knot nematode (RKN) Meloidogynespp. secrete effectors in a spatial and temporal manner to interfere with and mimic multiple physiological and morphological mechanisms, leading to modifications and reprogramming of the host cells' functions, resulted in construction and maintenance of nematodes' feeding sites. For successful parasitism, many effectors act as immunomodulators, aimed to manipulate and suppress immune defense signaling triggered upon nematode invasion. Plant development and defense rely mainly on hormone regulation. Herein, a metabolomic profiling of oxylipins and hormones composition of tomato roots were performed using LC-MS/MS, indicating a fluctuation in oxylipins profile in a compatible interaction. Moreover, further attention was given to uncover the implication of WRKYs transcription factors in regulating nematode development. In addition, in order to identify genes that might interact with the lipidomic defense pathway induced by oxylipins, a RNAseq was performed by exposing M. javanicasecond-stage juveniles to tomato protoplast, 9-HOT and 13-KOD oxylipins. This transcriptome generated a total of 4682 differentially expressed genes (DEGs). Being interested in effectors, we seek for DEGs carrying a predicted secretion signal peptide. Among the DEGs including signal peptide, several had homology with known effectors in other nematode species, other unknown potentially secreted proteins may have a role as root-knot nematodes' effectors which might interact with lipid signaling. The molecular interaction of LOX proteins with the Cyst nematode effectors illustrate the nematode strategy in manipulating plant lipid signals. The function of several other effectors in manipulating plant defense signals, as well as lipids signals, weakening cell walls, attenuating feeding site function and development are still being studied in depth for several novel effectors. As direct outcome of this project, the accumulating findings will be utilized to improve our understanding of the mechanisms governing critical life-cycle phases of the parasitic M. incognita RKN, thereby facilitating design of effective controls based on perturbation of nematode behavior—without producing harmful side effects. The knowledge from this study will promote genome editing strategies aimed at developing nematode resistance in tomato and other nematode-susceptible crop species in Israel and the United States.
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