Gotowe bibliografie tematyczne / Manipulators (Mechanism)

Gotowa bibliografia na temat „Manipulators (Mechanism)”

Autor: Grafiati
Data publikacji: 4 czerwca 2021
Data aktualizacji: 30 lipca 2024

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Artykuły w czasopismach na temat "Manipulators (Mechanism)"

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Liu, H., J. S. Dai, H. Y. Xu i H. Li. "Virtual-mechanism-based analysis of cooperative manipulation". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 219, nr 3 (1.03.2005): 315–23. http://dx.doi.org/10.1243/095440604x16830.

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This paper proposes a new approach for analysing cooperative manipulation in which cooperative manipulators form a mechanism closure that allows a virtual-mechanism-based analysis to take place. The method is based on the geometry of manipulators during manipulation and converts the cooperative manipulation problem into the analysis of a hypothetical mechanism so that the mechanism theory can be used for the manipulation. This mechanism is hence generated by the fact that the end points (or geometric centres of respective grippers) of cooperative manipulators coincide with a virtual joint during cooperative manipulation. The analysis not only generates positions and orientations of the end effectors of cooperative manipulators but also produces corresponding link configurations that can be used for manipulation planning. The approach is further used for the orientation-based trajectory planning with two different cases. Simulations and discussions are made with respect to cooperative manipulations using two 2R manipulators and one 2R manipulators and one 3R manipulator.
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Geonea, Ionut, Alexandru Margine i Alin Ungureanu. "Study upon the Dynamic Answer of Plane Manipulators". Advanced Materials Research 463-464 (luty 2012): 1304–8. http://dx.doi.org/10.4028/www.scientific.net/amr.463-464.1304.

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The paper illustrates the structure of plane mechanical systems used to manipulators. In the first part are presented some kinematics schemes used to plane manipulators. These mechanisms are used to manipulators, positioning and control systems. In generally these mechanisms have two or three degree of mobility. The purpose of the paper is to study the dynamics of a plane manipulator mechanical system used to manipulate garbage containers. It is presented the kinematics scheme of a plane manipulator, used to this purpose and is presented the mechanism functional description. In the second part is presented the kinematical and dynamical analysis for the plane manipulator mechanism. In the last part of the paper are presented graphical results for the dynamics parameters.
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Lu, Yi, Cong Cong, Chen Liwei i Peng Wang. "Solving elastic deformation of some parallel manipulators with linear active legs using computer-aided design variation geometry". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, nr 12 (19.02.2013): 2810–24. http://dx.doi.org/10.1177/0954406213478374.

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It has been a significant and challenging issue to determine the elastic deformation of parallel manipulators for their precision analysis and control. A new method is proposed and studied for solving the elastic deformation of some parallel manipulators with linear active legs using computer-aided design variation geometry. First, an original simulation mechanism of a parallel manipulator is constructed; each of the vectors in the force transformation matrix of the parallel manipulators is constructed by this simulation mechanism. The active/constrained wrench and their pose are determined based on the Newton–Euler formulation. Second, the elastic deformed dimensions of the active legs are determined based on the elastic deformation equation and the active/constrained wrench. Third, a new simulation mechanism of this parallel manipulator is constructed by replacing the original dimensions of active legs with the deformed dimensions of active legs and the elastic deformations of parallel manipulators are solved using the pose difference between the original and new simulation mechanisms. Finally, two parallel manipulators are illustrated and their elastic deformations are solved and verified by both analytic approach and finite element method.
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Dai, J. S., i P. Shah. "Orientation capability of planar serial manipulators using rotatability analysis based on workspace decomposition". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 216, nr 3 (1.03.2002): 275–88. http://dx.doi.org/10.1243/0954406021524990.

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This paper presents a new approach for analysing and synthesizing the orientation capability of planar serial manipulators. By relating the end-effector to the base joint of a manipulator using a virtual adjustable link, the paper converts the open-chain kinematic problem into that of an equivalent close-chain mechanism, and characterizes the relationship between the orientation capability of a serial manipulator and the rotatability of the equivalent mechanism. The orientation capability of a manipulator can hence be placed in the realm of mechanism rotatability. The approach is taken further by decomposing the reachable workspace of a manipulator into ranges, based on the extreme and singular positions of a manipulator. In each of the workspace ranges, the rotatability of the equivalent mechanism is examined and results are categorized to indicate the orientation capability of the manipulator. The approach produces a direct correlation between the orientation capability and manipulator parameters and generates a way of examining the orientation capabilities of serial manipulators. The approach is extended to n-link serial manipulators.
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Lu, Yi, i Bo Hu. "A Unified Approach to Solving Driving Forces in Spatial Parallel Manipulators With Less Than Six DOFs". Journal of Mechanical Design 129, nr 11 (3.11.2006): 1153–60. http://dx.doi.org/10.1115/1.2771237.

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A unified approach to solving driving forces in spatial parallel manipulators with less than six DOFs is proposed. First, the geometric constrained equations of the parallel manipulators are derived, and some independent pose parameters and a common transformation matrix with three translations and three Euler rotations are determined. Second, the common formulas for solving inverse kinematics, the Jacobian matrix, and velocity are derived. Third, a common virtual serial mechanism with three virtual prismatic joints and three virtual revolute joints corresponding to three Euler rotations is constructed. Fourth, a common analytic formula for solving driving forces in spatial parallel manipulators with less than six DOFs is derived by using the principle of virtual work and the virtual serial mechanism. Finally, a 3-SPR parallel manipulator with three DOFs and a 4SPS+SPR parallel manipulator with five DOFs are presented to illustrate the use of the unified approach to solve their inverse kinematics and the driving forces. The solving results are verified by the simulation mechanisms.
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Saito, Takashi Kei, Kento Onodera, Riku Seino, Takashi Okawa i Yasushi Saito. "300-N Class Convex-Based Telescopic Manipulator and Trial for 3-DOF Parallel Mechanism Robot". Journal of Robotics and Mechatronics 33, nr 1 (20.02.2021): 141–50. http://dx.doi.org/10.20965/jrm.2021.p0141.

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We designed a new telescopic manipulator that uses a clustered elastic convex tape. The manipulator has an ultra-wide expansion range and toughness against mechanical stress. Compared to conventional linear actuators, our convex-type manipulators have high extension range and are very lightweight. Moreover, they are compact when rolled up. The telescopic manipulators designed in the previous study had insufficient output due to structural problems and were unstable. In this study, we report a Type-K telescopic manipulator mechanism (Makijaku-Ude Type-K), which is a redesigned manipulator that can be easily used with a 300-N class power, and applied the mechanism to a three degrees-of-freedom spatial parallel-mechanism robot.
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Petrescu, Florian Ion, i Relly Victoria Petrescu. "Presenting a Railbound Forging Manipulator". Applied Mechanics and Materials 762 (maj 2015): 219–24. http://dx.doi.org/10.4028/www.scientific.net/amm.762.219.

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Heavy payload forging manipulators are mainly characterized by large load output and large capacitive load input. The relationships between outputs and inputs have greatly influence about the control and the reliability. Forging manipulators have become more prevalent in the industry today. They are used to manipulate objects to be forged. The most common forging manipulators are moving on a railway to have a greater precision and stability. They have been called the railbound forging manipulators. In this paper one presents the general aspects of a railbound forging manipulator, like geometry, structure, general kinematics and forces of the main mechanism from such manipulator. Kinematic scheme shows a typical forging manipulator, with the basic motions in operation process: walking, motion of the tong and buffering. The lifting mechanism consists of several parts including linkages, hydraulic drives and motion pairs. An idea of establishing the incidence relationship between output characteristics and actuator inputs is proposed.
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Ebert-Uphoff, Imme, Cle´ment M. Gosselin i Thierry Laliberte´. "Static Balancing of Spatial Parallel Platform Mechanisms—Revisited". Journal of Mechanical Design 122, nr 1 (1.01.2000): 43–51. http://dx.doi.org/10.1115/1.533544.

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This article discusses the development of statically balanced spatial parallel platform mechanisms. A mechanism is statically balanced if its potential energy is constant for all possible configurations. This property is very important for robotic manipulators with large payloads, since it means that the mechanism is statically stable for any configuration, i.e., zero actuator torques are required whenever the manipulator is at rest. Furthermore, only inertial forces and moments have to be sustained while the manipulator is moving. The application that motivates this research is the use of parallel platform manipulators as motion bases in commercial flight simulators, where the weight of the cockpit results in a large static load. We first present a class of spatial parallel platform mechanisms that is suitable for static balancing. The class of mechanisms considered is a generalization of the manipulator described by Streit (1991, “Spatial Manipulator and Six Degree of Freedom Platform Spring Equilibrator Theory,” in Second National Conference on Applied Mechanisms and Robotics, VIII.B, pp. 1-1–1-6). Then sufficient conditions on the kinematic parameters that guarantee static balancing are derived for this class. Finally a particular mechanism is studied in more detail to show the practicability of its design. [S1050-0472(00)01401-X]
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Ding, Wen Hua, Hua Deng, Yi Zhang i Yao Qing Ren. "Optimum Design of the Jaw Clamping Mechanism of Forging Manipulators Based on Force Transmissibility". Applied Mechanics and Materials 157-158 (luty 2012): 737–42. http://dx.doi.org/10.4028/www.scientific.net/amm.157-158.737.

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In this paper, the jaw clamping mechanism of a forging manipulator is regarded as a slider-crank mechanism. First, the force Jacobian matrix of the mechanism is obtained according to the dual relationship of velocity Jacobian matrix and force Jacobian matrix. Then, the performance atlases of the global force transmission index and the input space index that represents the motion range of the jaw are drawn with different inputs for the mechanisms of the nondimensional parameters. Furthermore, we research the effect of these structure parameters of the mechanism on the gripping force transmission and input space, and find an optimal range in the force transmission atlas. Finally, we synthesize a detail optimal flowchart of the jaw clamping mechanism of forging manipulators based on force transmissibility. A jaw clamping mechanism of a forging manipulator is studied as an example, and results show that the method presented in this paper is effective for finding an optimal gripper mechanism. The research in this paper can be served as fundamentals of design and optimization of the jaw clamping mechanism of forging manipulators.
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Sundar, Syam, Vijay S. Rathore, Manoj K. Sahi, V. Upendran i Anjan Kumar Dash. "Workspace Analysis and Going through Singularities of 5-Bar Symmetric Planar Parallel Manipulator by Automated Selective Actuation Mechanism". Advanced Materials Research 588-589 (listopad 2012): 1664–68. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.1664.

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In this article‚ a new approach is presented to determine the various shapes of workspaces of 5 bar symmetric planar parallel manipulators. Here the shape of the workspace is determined by the number of ways the workspaces of the two serial manipulators intersect with each other. Geometric conditions are established in each case and area of each shape of workspace is determined in closed form. Singularity is another important consideration in the design of parallel manipulators. In this paper, an approach is presented to go through the singularity points using an automatic selective actuation mechanism. A prototype 5-bar planar manipulator is fabricated along with an automatic selective actuation mechanism demonstrating the manipulator going through the singularity points.
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Rozprawy doktorskie na temat "Manipulators (Mechanism)"

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Hopkins, Brian. "Modified ParaDex: Theory and hardware implementation of a 6-prismatic-spherical-universal parallel manipulator". Ohio : Ohio University, 2001. http://www.ohiolink.edu/etd/view.cgi?ohiou1173899557.

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Lee, Kam-fat Jonathan. "Design and control of a robotic manipulator with an active pneumatic balancing system /". [Hong Kong] : University of Hong Kong, 1992. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13194367.

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Oosting, Kenneth W. "Simulation of control strategies for a two degree-of-freedom lightweight flexible robotic arm". Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/18230.

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Alberts, Thomas Edward. "Augmenting the control of a flexible manipulator with passive mechanical damping". Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/19442.

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Hastings, Gordon Greene. "Controlling flexible manipulators, an experimental investigation". Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/16691.

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Gupta, Pramod. "Neurocontrol of robotic manipulators". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0018/NQ42740.pdf.

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Smith, David Rowland. "Design of solvable 6R manipulators". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/18861.

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Yiu, Yiu Kuen. "Geometry, dynamics and control of parallel manipulators /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202002%20YIU.

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Lou, Yunjiang. "Optimal design of parallel manipulators /". View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?ECED%202006%20LOU.

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Tahboub, Karim Abdul Majid. "Digital control for flexible manipulator arms". Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/17210.

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Książki na temat "Manipulators (Mechanism)"

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1965-, Böhringer Karl F., i Choset Howie M, red. Distributed manipulation. Boston: Kluwer Academic, 2000.

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Balafoutis, C. A. Dynamic analysis of robot manipulators: A Cartesian tensor approach. Boston: Kluwer Academic Publishers, 1991.

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X, Liu John, red. Robots manipulators: New research. New York: Nova Science, 2005.

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Maurine, Patrick. Calibration of industrial robot manipulators. London, UK: ISTE, 2011.

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Höfer, Angelika. Steuerung der Konfiguration eines redundanten Manipulators. Wiesbaden: Vieweg, 1992.

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Peshkin, M. A. Robotic manipulation strategies. Englewood Cliffs, N.J: Prentice Hall, 1990.

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RoManSy (9th 1992 Udine, Italy). RoManSy 9: Proceedings of the Ninth CISM-IFToMM Symposium on Theory and Practice of Robots and Manipulators. London: Springer-Verlag, 1993.

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Fraser, Anthony R. Perturbation techniques for flexible manipulators. Boston: Kluwer Academic Publishers, 1991.

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Marcos, Salganicoff, i Society of Photo-optical Instrumentation Engineers., red. Telemanipulator and telepresence technologies II: 25-26 October 1995, Philadelphia, Pennsylvania. Bellingham, Wash: SPIE, 1995.

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Michel, Le Borgne, i Espiau Bernard, red. Robot control: The task function approach. Oxford: Clarendon Press, 1991.

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Części książek na temat "Manipulators (Mechanism)"

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Chebab, Zine Elabidine, Jean-Christophe Fauroux, Grigore Gogu, Laurent Sabourin, Nicolas Bouton i Youcef Mezouar. "Structural Analysis of Mobile Manipulators". W Advances in Mechanism and Machine Science, 2661–70. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20131-9_263.

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de-Juan, A., J. F. Collard, P. Fisette, P. Garcia i R. Sancibrian. "Multi-Objective Optimization of Parallel Manipulators". W New Trends in Mechanism Science, 633–40. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9689-0_72.

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Wu, Yuanqing, i Marco Carricato. "Unified Pose Parametrization for 1T2R Parallel Manipulators". W Mechanism Design for Robotics, 57–68. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00365-4_8.

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Husty, Manfred L., i Dominic R. Walter. "Mechanism Constraints and Singularities—The Algebraic Formulation". W Singular Configurations of Mechanisms and Manipulators, 101–80. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05219-5_4.

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Pashkevich, A., A. Klimchik, S. Caro i D. Chablat. "Stiffness Modelling of Parallelogram-Based Parallel Manipulators". W New Trends in Mechanism Science, 675–82. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9689-0_77.

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Husty, Manfred, Josef Schadlbauer, Stéphane Caro i Philippe Wenger. "Self-Motions of 3-RPS Manipulators". W New Trends in Mechanism and Machine Science, 121–30. Dordrecht: Springer Netherlands, 2012. http://dx.doi.org/10.1007/978-94-007-4902-3_13.

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Glazunov, Victor, Natalya Nosova, Sergey Kheylo i Andrey Tsarkov. "Design and Analysis of the 6-DOF Decoupled Parallel Kinematics Mechanism". W Dynamic Decoupling of Robot Manipulators, 125–70. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-74363-9_6.

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Wu, Yuanqing, i Marco Carricato. "Correction to: Unified Pose Parametrization for 1T2R Parallel Manipulators". W Mechanism Design for Robotics, E1. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-00365-4_53.

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Amirinezhad, S. Vahid, i Peter Donelan. "Input and output singularities for parallel manipulators". W Advances in Mechanism and Machine Science, 289–98. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20131-9_29.

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Corral, J., Ch Pinto, M. Urizar i V. Petuya. "Structural Dynamic Analysis of Low-Mobility Parallel Manipulators". W New Trends in Mechanism Science, 387–94. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-90-481-9689-0_45.

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Streszczenia konferencji na temat "Manipulators (Mechanism)"

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Li, Yanwen, Yueyue Zhang, Lumin Wang i Zhen Huang. "A Novel Parallel Mechanism With 3-RRUR Legs". W ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-43295.

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This paper investigates a novel 4-DOF 3-RRUR parallel manipulator, the number and the characteristics of its degrees of freedom are determined firstly, the rational input plan and the invert and forward kinematic solutions are carried out then. The corresponding numeral example of the forward kinematics is given. This type of parallel manipulators has a symmetrical structure, less accumulated error, and can be used to construct virtual-axis machine tools. The analysis in this paper will play an important role in promoting the application of such manipulators.
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Lu, Yi, i Yonghe Zhao. "Position and Workspace Analyses of 3-SPR and 3-RPS Parallel Manipulators". W ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84117.

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An analytic approach and a simulation mechanism for solving position and the workspace of a 3-SPR parallel manipulator are proposed. First, a simulation mechanism of the 3-SPR parallel manipulator and a simulation mechanism of the 3-RPS parallel manipulator are created by using the computer aided geometry constraints and dimension-driving techniques. Second, some analytic formulas are derived for inverse and forward solving position and orientation of the 3-SPR parallel manipulator. Third, some available solutions from multi-solutions during deriving analytic formula are determined, and analytic inverse and forward solutions are verified by using simulation mechanisms. Finally, the workspace of the 3-SPR parallel manipulator is created and three key parameters for determining work space of two kinds of parallel manipulators are solved. Calculation results prove that the position working space of the 3-SPR parallel manipulator is much larger than that of the 3-RPS parallel manipulator, and the orientation workspace of the 3-SPR parallel manipulator is less than that of 3-RPS parallel manipulator.
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Posmetev, Valeriy, Vadim Nikonov, A. Mihailov i I. Hrapov. "ON THE PERSPECTIVE OF THE USE OF HYDROCYLINDERS IN THE ROTARY MECHANISM OF THE HYDRAULIC COLUMN MANIPULATOR OF THE TIMBER ROAD TRAIN". W Innovations in road transport. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2022. http://dx.doi.org/10.34220/irt2022_4-9.

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The urgency of the need to improve the efficiency of hydraulic manipulators in-volved in the timber complex of the Russian Federation during the loading and unloading of timber is substantiated. The negative consequences of the impact of dynamic loads on the rotary mechanisms of hydraulic manipulators in the process of loading and unloading timber are considered. A promising de-sign is presented, which makes it possible to significantly reduce the dynamic loads acting on the rotary mechanism of the hydraulic manipulator. A perspective scheme of the rotary mechanism of a hydraulic manipulator column with a crankshaft drive from two hydraulic cylinders is proposed. The main ad-vantages of such a rotary column mechanism with a recuperative hydraulic drive are described. The main tasks are formulated that contribute to the acceleration of the process of development and practical implementation of a prototype of the proposed mechanism.
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Zhang, Change-de, i Shin-Min Song. "Geometry and Position Analysis of a Novel Class of Hybrid Manipulators". W ASME 1994 Design Technical Conferences collocated with the ASME 1994 International Computers in Engineering Conference and Exhibition and the ASME 1994 8th Annual Database Symposium. American Society of Mechanical Engineers, 1994. http://dx.doi.org/10.1115/detc1994-0300.

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Abstract This paper presents a novel class of hybrid manipulators composed of two serially connected parallel mechanisms, each of which has three degrees of freedom. The lower and upper platforms respectively control the position and orientation of the end-effector. The advantages of this type of hybrid manipulator are larger workspace (as compared with parallel manipulators) and better rigidity and higher load-carrying capability (as compared with serial manipulators). The closed-form solutions of the forward and inverse position analyses are discussed. For forward position analysis, it is shown that the resultant equation for the positional mechanism is an 8-th order, a 6-th order, a 4-th order, or a 2-nd order polynomial, depending on the geometry and joint types of the passive subchain, while for the orientational mechanism, it is an 8-th order, or a 2-nd polynomial depending on the geometry. For inverse position analysis, it is demonstrated that the positional and orientational mechanisms both possess analytical closed-form solutions.
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Ebert-Uphoff, Imme, Clément M. Gosselin i Thierry Laliberté. "Static Balancing of a Class of Spatial Parallel Platform Mechanisms". W ASME 1998 Design Engineering Technical Conferences. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/detc98/mech-5964.

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Abstract This article discusses the development of statically balanced spatial parallel platform mechanisms. A mechanism is statically balanced if its potential energy is constant for all possible configurations. This property is very important for robotic manipulators with large payloads, since it means that the mechanism is statically stable for any configuration, i.e. zero actuator forces are required whenever the manipulator is at rest. Furthermore, only inertial forces have to be sustained while the manipulator is moving. The application that motivates this research is the use of parallel platform manipulators as motion bases in commercial flight simulators, where the weight of the cockpit results in a large static load. We first present a class of spatial parallel platform mechanisms of novel architecture that is suitable for static balancing. Then sufficient conditions on the kinematic parameters that guarantee static balancing are derived for this class. Finally a particular mechanism is studied in more detail to show the practicability of its design.
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Tolstosheev, Andrey, i Vyacheslav Tatarincev. "SYNTHESIS OF STATICALLY DETERMINED ISOTROPIC PARALLEL MANIPULATORS OF THE PANTOPTERON TYPE". W PROBLEMS OF APPLIED MECHANICS. Bryansk State Technical University, 2020. http://dx.doi.org/10.30987/conferencearticle_5fd1ed03a68810.94405173.

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Isotropic parallel manipulators are considered. The analysis of the structure and kinematics of the parallel translational directional manipulator Pantopteron is carried out. It was found that the Pantopteron mechanism, in the kinematic chain of which pantographs are included in order to increase the speed, contains redundant links and is statically indeterminate. Structural schemes of statically definable parallel manipulators of the Pantopteron type have been developed and proposed.
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Malik, Akhtar N., Jian S. Dai i Gordon R. Pennock. "Constraint Redundancy in Mobility of Parallel Manipulators". W ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49759.

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This paper presents a systematic approach to obtain the degrees of freedom (DOF) of the platforms of parallel manipulators. The paper begins with general Kutzbach criterion for mobility. With simple mathematical transformations this criterion is modified to incorporate number of parallel legs used in the parallel platform-type mechanism and the number of joints in the legs. The theory of screws is used to study the freedom of the joints in the individual legs and the mobility of the platform. It is established that the general Kutzbach mobility criterion does not cater for situations where the freedom screws (or constraint screws) of the joints in a leg become dependent on the freedom screws (or constraint screws) of one or more of the other legs; thus, altering the mobility of the platform. The general modified Kutzbach mobility formula is further modified to resolve the problem of redundant constraints. The paper then provides a systematic approach towards the number synthesis of parallel platform-type mechanims. The paper includes three examples of such mechanisms analyzed by this approach. Results agree with the existing studies carried out on the mechanism used in the examples. A numerical example of a three-degree-of-freedom parallel manipulator with three legs is used to show the enumeration of all possible parallel manipulators. This includes cases with and without redundant constraints.
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Sharifzadeh, Mohammad, Yuhao Jiang, Roozbeh Khodambashi i Daniel Aukes. "Increasing the Life Span of Foldable Manipulators With Fabric". W ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/detc2020-22757.

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Abstract This paper evaluates how laminated techniques may be used to replicate the performance of more traditionally manufactured robotic manipulators. This evaluation is conducted by addressing the advantages and challenges of laminated manufacturing techniques, specifcally mechanism durability. In this study, we propose a novel fabric-polyester hinge design with an improved life-span. We additionally provide an overview of the design and construction workfow for a laminated 2-DOF spherical parallel manipulator for use as a camera stabilizer. Using the proposed manipulator as a case study, we demonstrate that mechanisms fabricated with lamination techniques can achieve similar performance to devices made using conventional methods.
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El-Khasawneh, Bashar, i Anas Alazzam. "Kinematics, Dynamics and Vibration Models for 3RPR Parallel Kinematics Manipulator". W ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64525.

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Parallel link manipulators are the type of mechanisms that have closed kinematics chains. Some of their advantages over open kinematics chains (called also serial kinematics manipulators) are their high stiffness and accuracy. This paper carries out forward and inverse kinematic and dynamic analysis on a certain type of parallel kinematic mechanisms. This is needed to conduct vibration analysis on the same platform. The type of mechanism is planar 3 RPR manipulator. This entails identifying the modes of the manipulator. A simplified vibration theoretical model is derived. This derivation helps in the optimization of parallel kinematics machine design for improved/optimized dynamic performance. The implications of dynamic stiffness modeling should reflect on better noise rejection, less chatter during machining, and increasing the bandwidth of such mechanisms to admit running at higher speeds.
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Nelson, Carl A., i Xiaoli Zhang. "Equivalent Mechanisms Techniques for Redesign of a Spherical Surgical Tool Manipulator". W ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28367.

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In the design of robotic manipulators for minimally invasive surgery (MIS), the spherical mechanism is a very important kinematic entity, since it can be used to mimic the constraint that the incision point provides to the surgical tool. In previous research by the authors, a bevel-gear-based spherical manipulator was designed whose actuators could be located on a fixed base link. In this paper, concepts of mechanism equivalency are applied to improving the manipulator design. The guidelines arrived at in this work can inform design of future spherical manipulators, especially those created with surgical tool manipulation in mind.
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Raporty organizacyjne na temat "Manipulators (Mechanism)"

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Christie, Benjamin, Jordan Klein, Anton Netchaev i Garry Glaspell. Integrating MOVEit motion constraints on a novel robotic manipulator. Engineer Research and Development Center (U.S.), listopad 2023. http://dx.doi.org/10.21079/11681/47845.

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MOVEit, a widely used Robot Operating System framework, plans composite tasks, where the high-level sequence of actions is fixed and known in advance. However, these tasks need to be tailored and adapted to the environmental context. This framework uses custom trajectory planners, known as controllers, to solve goals that are fully defined within the configuration space. Libraries, such as the Open Motion Planning Library, provide a collection of motion planners that can solve task-space goals. An exact spatial and joint replication of the robotic manipulator’s mechanics, typically Universal Robot Description Format and Semantic Robot Description Format files, is required. Common arms such as the Panda-Manipulator and OpenMANIPULATOR-X provide these files in their respective public repositories, but custom arms require significant modification or even a complete rewrite of these files.
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Gothilf, Yoav, Roger Cone, Berta Levavi-Sivan i Sheenan Harpaz. Genetic manipulations of MC4R for increased growth and feed efficiency in fish. United States Department of Agriculture, styczeń 2016. http://dx.doi.org/10.32747/2016.7600043.bard.

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The hypothalamic melanocortin system plays a central role in the regulation of food consumption and energy homeostasis in mammals. Accordingly, our working hypothesis in this project was that genetic editing of the mc4r gene, encoding Melanocortin Receptor 4 (MC4R), will enhance food consumption, feed efficiency and growth in fish. To test this hypothesis and to assess the utility of mc4r editing for the enhancement of feed efficiency and growth in fish, the following objectives were set: Test the effect of the mc4r-null allele on feeding behavior, growth, metabolism and survival in zebrafish. Generate mc4r-null alleles in tilapia and examine the consequences for growth and survival, feed efficiency and body composition. Generate and examine the effect of naturally-occurring mc4r alleles found in swordfish on feeding behavior, growth and survival in zebrafish. Define the MC4R-mediated and MC4R-independent effects of AgRP by crossing mc4r- null strains with fish lacking AgRP neurons or the agrpgene. Our results in zebrafish did not support our hypothesis. While knockout of the agrpgene or genetic ablation of hypothalamic AgRP neurons led to reduced food intake in zebrafish larvae, knockout (KO) of the mc4r gene not only did not increase the rate of food intake but even reduced it. Since Melanocortin Receptor 3 (MC3R) has also been proposed to be involved in hypothalamic control of food intake, we also tested the effectofmc3r gene KO. Again, contrary to our hypothesis, the rate of food intake decreased. The next step was to generate a double mutant lucking both functional MC3R and MC4R. Again, the double KO exhibited reduced food intake. Thus, the only manipulation within the melanocortin system that affected food intake in consistent with the expected role of the system was seen in zebrafish larvae upon agrpKO. Interestingly, despite the apparent reduced food intake in the larval stage, these fish grow to be of the same size as wildtype fish at the adult stage. Altogether, it seems that there is a compensatory mechanism that overrides the effect of genetic manipulations of the melanocortin system in zebrafish. Under Aim 3, we introduced the Xna1, XnB1l, and XnB2A mutations from the Xiphophorus MC4R alleles into the zebrafish MC4R gene. We hypothesized that these MC4R mutations would act as dominant negative alleles to increase growth by suppressing endogenous MC4R activity. When we examined the activity of the three mutant alleles, we were unable to document any inhibition of a co-transfected wild type MC4R allele, hence we did not introduce these alleles into zebrafish. Since teleost fish possess two agrpgenes we also tested the effect of KO of the agrp2 gene and ablation of the AgRP2 cells. We found that the AgRP2 system does not affect food consumption but may rather be involved in modulating the stress response. To try to apply genetic editing in farmed fish species we turned to tilapia. Injection of exogenous AgRP in adult tilapia induced significant changes in the expression of pituitary hormones. Genetic editing in tilapia is far more complicated than in zebrafish. Nevertheless, we managed to generate one mutant fish carrying a mutation in mc4r. That individual died before reaching sexual maturity. Thus, our attempt to generate an mc4r-mutant tilapia line was almost successful and indicate out non-obvious capability to generate mutant tilapia.
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Hulata, Gideon, Thomas D. Kocher, Micha Ron i Eyal Seroussi. Molecular Mechanisms of Sex Determination in Cultured Tilapias. United States Department of Agriculture, październik 2010. http://dx.doi.org/10.32747/2010.7697106.bard.

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Tilapias are among the most important aquaculture commodities worldwide. Commercial production of tilapia is based on monosex culture of males. Current methods for producing all-male fingerlings, including hormone treatments and genetic manipulations, are not entirely reliable, in part because of the genetic complexity of sex determination and sexual differentiation in tilapias. The goals of this project are to map QTL and identify genes regulating sex determination in commonly cultured tilapia species, in order to provide a rational basis for designing reliable genetic approaches for producing all-male fingerlings. The original objectives for this research were: 1) to identify the gene underlying the QTL on LG1 through positional cloning and gene expression analysis; 2) to fine map the QTL on LG 3 and 23; and 3) to characterize the patterns of dominance and epistasis among QTL alleles influencing sex determination. The brain aromatase gene Cyp19b, a possible candidate for the genetic or environmental SD, was mapped to LG7 using our F2 mapping population. This region has not been identified before as affecting SD in tilapias. The QTL affecting SD on LG 1 and 23 have been fine-mapped down to 1 and 4 cM, respectively, but the key regulators for SD have not been found yet. Nevertheless, a very strong association with gender was found on LG23 for marker UNH898. Allele 276 was found almost exclusively in males, and we hypothesized that this allele is a male-associated allele (MAA). Mating of males homozygous for MAA with normal females is underway for production of all-male populations. The first progeny reaching size allowing accurate sexing had 43 males and no females. During the course of the project it became apparent that in order to achieve those objectives there is a need to develop genomic infrastructures that were lacking. Efforts have been devoted to the development of genomic resources: a database consisting of nearly 117k ESTs representing 16 tissues from tilapia were obtained; a web tool based on the RepeatMasker software was designed to assist tilapia genomics; collaboration has been established with a sequencing company to sequence the tilapia genome; steps have been taken toward constructing a microarray to enable comparative analysis of the entire transcriptome that is required in order to detect genes that are differentially expressed between genders in early developmental stages. Genomic resources developed will be invaluable for studies of cichlid physiology, evolution and development, and will hopefully lead to identification of the key regulators of SD. Thus, they will have both scientific and agricultural implications in the coming years.
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Elizur, Abigail, Amir Sagi, Gideon Hulata, Clive Jones i Wayne Knibb. Improving Crustacean Aquaculture Production Efficiencies through Development of Monosex Populations Using Endocrine and Molecular Manipulations. United States Department of Agriculture, czerwiec 2010. http://dx.doi.org/10.32747/2010.7613890.bard.

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Background Most of Australian prawn aquaculture production is based on P. monodon. However, the Australian industry is under intense competition from lower priced overseas imports. The availability of all-female monosex populations, by virtue of their large size and associated premium prize, will offer competitive advantage to the industry which desperately needs to counteract competitors within this market. As for the redclaw production in Israel, although it is at its infancy, the growers realized that the production of males is extremely advantageous and that such management strategy will change the economic assumptions and performances of this aquaculture to attract many more growers. Original objectives (as in original proposal) Investigating the sex inheritance mechanism in the tiger prawn. Identification of genes expressed uniquely in the androgenic gland (AG) of prawns and crayfish. The above genes and/or their products will be used to localize the AG in the prawn and manipulate the AG activity in both species. Production of monosex populations through AG manipulation. In the prawn, production of all-female populations and in the crayfish, all-male populations. Achievements In the crayfish, the AG cDNA library was further screened and a third AG specific transcript, designated Cq-AG3, had been identified. Simultaneously the two AG specific genes, which were previously identified, were further characterized. Tissue specificity of one of those genes, termed Cq-AG2, was demonstrated by northern blot hybridization and RNA in-situ hybridization. Bioinformatics prediction, which suggested a 42 amino acid long signal anchor at the N-terminus of the deduced Cq-AG2, was confirmed by immunolocalization of a recombinant protein. Cq-IAG's functionality was demonstrated by dsRNA in-vivo injections to intersex crayfish. Cq-IAGsilencing induced dramatic sex-related alterations, including male feature feminization, reduced sperm production, extensive testicular apoptosis, induction of the vitellogeningene expression and accumulation of yolk proteins in the ovaries. In the prawn, the AG was identified and a cDNA library was created. The putative P. monodonAG hormone encoding gene (Pm-IAG) was identified, isolated and characterized for time of expression and histological localization. Implantation of the AG into prawn post larvae (PL) and juveniles resulted in phenotypic transformation which included the appearance of appendix masculina and enlarged petasma. The transformation however did not result in sex change or the creation of neo males thus the population genetics stage to be executed with Prof. Hulata did not materialized. Repeated AG implantation is currently being trialed. Major conclusions and Implications, both scientific and agricultural Cq-IAG's involvement in male sexual differentiation had been demonstrated and it is strongly suggested that this gene encodes an AG hormone in this crayfish. A thorough screening of the AG cDNA library shows Cq-IAG is the prominent transcript within the library. However, the identification of two additional transcripts hints that Cq-IAG is not the only gene mediating the AG effects. The successful gene silencing of Cq-IAG, if performed at earlier developmental stages, might accomplish full and functional sex reversal which will enable the production of all-male crayfish populations. Pm-IAG is likely to play a similar role in prawns. It is possible that repeated administration of the AG into prawn will lead to the desired full sex reversal, so that WZ neo males, crossed with WZ females can result in WW females, which will form the basis for monosex all-female population.
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Matthew, Gray. Data from "Winter is Coming – Temperature Affects Immune Defenses and Susceptibility to Batrachochytrium salamandrivorans". University of Tennessee, Knoxville Libraries, styczeń 2021. http://dx.doi.org/10.7290/t7sallfxxe.

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Environmental temperature is a key factor driving various biological processes, including immune defenses and host-pathogen interactions. Here, we evaluated the effects of environmental temperature on the pathogenicity of the emerging fungus, Batrachochytrium salamandrivorans (Bsal), using controlled laboratory experiments, and measured components of host immune defense to identify regulating mechanisms. We found that adult and juvenile Notophthalmus viridescens died faster due to Bsal chytridiomycosis at 14 ºC than at 6 and 22 ºC. Pathogen replication rates, total available proteins on the skin, and microbiome composition likely drove these relationships. Temperature-dependent skin microbiome composition in our laboratory experiments matched seasonal trends in wild N. viridescens, adding validity to these results. We also found that hydrophobic peptide production after two months post-exposure to Bsal was reduced in infected animals compared to controls, perhaps due to peptide release earlier in infection or impaired granular gland function in diseased animals. Using our temperature-dependent infection results, we performed a geographic analysis that suggested that N. viridescens populations in the northeastern United States and southeastern Canada are at greatest risk for Bsal invasion. Our results indicate that environmental temperature will play a key role in the epidemiology of Bsal and provide evidence that temperature manipulations may be a viable Bsal management strategy.
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Eshed, Yuval, i John Bowman. Harnessing Fine Scale Tuning of Endogenous Plant Regulatory Processes for Manipulation of Organ Growth. United States Department of Agriculture, 2005. http://dx.doi.org/10.32747/2005.7696519.bard.

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Background and objectives: Manipulation of plant organ growth is one of the primary reasons for the success of mankind allowing increasing amounts of food for human and livestock consumption. In contrast with the successful selection for desirable growth characteristics using plant breeding, transgenic manipulations with single genes has met limited success. While breeding is based on accumulation of many small alterations of growth, usually arise from slight changes in expression patterns, transgenic manipulations are primarily based on drastic, non-specific up-regulation or knock down of genes that can exert different effects during different stages of development. To successfully harness transgenic manipulation to attain desirable plant growth traits we require the tools to subtly regulate the temporal and spatial activity of plant growth genes. Polar morphology along the adaxial/abaxial axis characterizes lateral organs of all plants. Juxtaposition of two cell types along this axis is a prerequisite of laminar growth induction. In the study summarized here, we addressed the following questions: Can we identify and harness components of the organ polarity establishment pathway for prolonged growth? Can we identify specific regulatory sequences allowing spatial and temporal manipulation in various stages of organ development? Can we identify genes associated with YABBY-induced growth alterations? Major conclusions and implications: We showed that regulated expression, both spatially and temporally of either organ polarity factors such as the YABBY genes, or the organ maturation program such as the CIN-TCPs can stimulate substantial growth of leaves and floral organs. Promoters for such fine manipulation could be identified by comparison of non-coding sequences of KAN1, where a highly conserved domain was found within the second intron, or by examination of multiple 5” regions of genes showing transient expression along leaf ontogeny. These promoters illustrate the context dependent action of any gene we examined thus far, and facilitate fine tuning of the complex growth process. Implications, both scientific and agricultural. The present study was carried out on the model organism Arabidopsis, and the broad application of its findings were tested in the tomato crop. We learned that all central regulators of organ polarity are functionally conserved, probably in all flowering plants. Thus, with minor modifications, the rules and mechanisms outlined in this work are likely to be general.
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Morrison, Mark, i Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, listopad 2000. http://dx.doi.org/10.32747/2000.7695844.bard.

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At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.
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Meir, Shimon, Michael S. Reid, Cai-Zhong Jiang, Amnon Lers i Sonia Philosoph-Hadas. Molecular Studies of Postharvest Leaf and Flower Senescence. United States Department of Agriculture, styczeń 2011. http://dx.doi.org/10.32747/2011.7592657.bard.

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Original objectives: To understand the regulation of abscission by exploring the nature of changes of auxin-related gene expression in tomato (Lycopersicon esculatumMill) abscission zones (AZs) following organ removal, and by analyzing the function of these genes. Our specific goals were: 1) To complete the microarray analyses in tomato flower and leaf AZs, for identifying genes whose expression changes early in response to auxin depletion; 2) To examine, using virus-induced gene silencing (VIGS), the effect of silencing target genes on ethylene sensitivity and abscission competence of the leaf and flower AZs; 3) To isolate and characterize promoters from AZ-specific genes to be used in functional analysis; 4) To generate stable transgenic tomato plants with selected genes silenced with RNAi, under the control of an AZ-specific promoter, for further characterization of their abscission phenotypes. Background: Abscission, the separation of organs from the parent plant, results in postharvest quality loss in many ornamentals and other fresh produce. The process is initiated by changes in the auxin gradient across the AZ, and is triggered by ethylene. Although changes in gene expression have been correlated with the ethylene-mediated execution of abscission, there is almost no information on the initiation of the abscission process, as the AZ becomes sensitized to ethylene. The present project was focused on elucidating these early molecular regulatory events, in order to gain a better control of the abscission process for agricultural manipulations. Major conclusions, solutions, achievements: Microarray analyses, using the Affymetrix Tomato GeneChip®, revealed changes in expression, occurring early in abscission, of many genes with possible regulatory functions. These included a range of auxin- and ethylene-related transcription factors (TFs), other TFs that are transiently induced just after flower removal, and a set of novel AZ-specific genes. We also identified four different defense-related genes, including: Cysteine-type endopeptidase, α- DOX1, WIN2, and SDF2, that are newly-associated with the late stage of the abscission process. This supports the activation of different defense responses and strategies at the late abscission stages, which may enable efficient protection of the exposed tissue toward different environmental stresses. To facilitate functional studies we implemented an efficient VIGS system in tomato, and isolated two abscission-specific promoters (pTAPG1 and pTAPG4) for gene silencing in stable transformation. Using the VIGS system we could demonstrate the importance of TAPGs in abscission of tomato leaf petioles, and evaluated the importance of more than 45 genes in abscission. Among them we identified few critical genes involved in leaf and flower abscission. These included: PTRP-F1, PRP, TKN4, KNOTTED-like homeobox TF, KD1, and KNOX-like homeodomain protein genes, the silencing of which caused a striking retardation of pedicel abscission, and ERF1, ERF4, Clavata-like3 protein, Sucrose transporter protein, and IAA10 genes, the silencing of which delayed petiole abscission. The importance of PRPand KD1 genes in abscission was confirmed also by antisense–silencing using pTAPG4. Experiments testing the effects of RNAi silencing of few other genes are still in progress, The analysis of the microarray results of flower and leaf AZs allowed us to establish a clear sequence of events occurring during acquisition of tissue sensitivity to ethylene, and to confirm our hypothesis that acquisition of ethylene sensitivity in the AZ is associated with altered expression of auxin-regulated genes in both AZs. Implication, both scientific and agricultural: Our studies had provided new insights into the regulation of the abscission process, and shaded light on the molecular mechanisms that drive the acquisition of abscission competence in the AZ. We pointed out some critical genes involved in regulation of abscission, and further expanded our knowledge of auxin-ethylene cross talk during the abscission process. This permits the development of novel techniques for manipulating abscission, and thereby improving the postharvest performance of ornamentals and other crops.
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