102,138 research outputs found
Glucose-6-phosphate dehydrogenase in small intestine of rabbit: biochemical properties and subcellular localization
No full textBiochemical properties and cellular and subcellular distribution patterns of glucose-6-phosphate dehydrogenase (G6PD) were investigated in small intestine of rabbits. The specific activity of G6PD in fresh homogenates of small intestine was 19 ± 9 IU/g protein. This value did not change significantly after dialysis. The kinetic and electrophoretic properties of the partially purified enzyme were similar to those found in other rabbit tissues. Enzyme histochemical analysis of G6PD activity using the tetrazolium salt method showed high activity in epithelial cells of villi and crypts of Lieberkuïhn. The activity in acinar cells of Brunner's glands was lower than that in epithelium, whereas cells of the muscularis externa showed a very low activity. Immunohistochemical analysis showed that the amounts of G6PD protein were lower in the epithelium than in Brunner's glands and muscularis externa. The differences between distribution patterns of activity and protein of G6PD may reflect the presence of inactive enzyme molecules in Brunner's glands and muscularis externa or posttranslational activation of G6PD in epithelium. Electron microscopic immunocytochemical analysis performed with gold-labelled antibodies showed the presence of G6PD protein throughout the cytoplasm and at smooth endoplasmic reticulum in enterocytes. In Paneth cells and cells of Brunner's glands, G6PD was found in the cytoplasm, at rough endoplasmic reticulum and Golgi complex. Immunolabelling was not found in mitochondria or nuclei. Our findings show that G6PD is heterogeneously distributed in cells of the small intestine and that the enzyme is associated with rough and smooth endoplasmic reticulum to support synthetic functions in these compartments by NADPH production
Chemistry of α-mangostin : studies on the semisynthesis of minor xanthones from Garcinia mangostana
No full textα-Mangostin is the major prenylated xanthone from Garcinia mangostana and it has been used also in recent times as starting material for the semisynthetic preparation of various biologically active derivatives. Its structure is characterised by the presence of few functional groups amenable to chemical manipulations, but present in the molecule in multiple instances (three phenolic hydroxyl groups, two prenyl chains and two unsubstituted aromatic carbons). This study represents a first approach to the systematic investigation of the reactivity of α-mangostin and describes the semisynthesis of some minor xanthones isolated from G. mangostana
A dexterous robotic gripper for autonomous grasping
No full textIn advanced robotics applications in unstructured environments (e.g. those foreseen in space) some degree of dexterity and autonomy is necessary in order to safely and successfully execute the required tasks. With this respect, besides the kinematic configuration, important aspects to be considered in the design of robotic end-effectors are the sensorial equipment and proper control strategies. In this paper, an activity for designing and experimenting a gripper for this operation in unstructured environments is reported, and laboratory results are presented and discussed
Position/force control of an arm/gripper system for space manipulation
No full textIn advanced robotics applications, as those foreseen in space, some degree of dexterity and autonomy is necessary in order execute tasks in unstructured environments. For this purpose besides the kinematic configuration of the device other basic issues are the sensorial equipment and proper control strategies. This paper presents an experimental activity for the validation of a robotic gripper for space applications. In particular the project foresees the compatibility of the gripper with the EUROPA arm, developed by ASI and Tecnospazio. Main Key points of the gripper design are the wide working space compared with its physical dimensions and the capability to deal with free-flying objects in no-gravity conditions. This capability is achieved by using proximity and force/torque sensor and by properly controlling and coordinating the gripper and the carrying arm. After a brief illustration on the main features of the gripper, the experimental activity is presented and the results achieved so far are discu ssed
Control of a robotic gripper for grasping objects in no-gravity conditions
No full textIn space applications, it is conceivable that part of the robotic activities could involve the grasp and/or manipulation of free-floating objects in absence of gravity. In this case, synchronous application of contacts seems to represent a basic feature in order to efficiently grasp the floating items. In this sense, an additional difficulty is that objects may have irregular shape and/or be non well positioned in the gripper workspace. These difficulties cannot be handled in a simple way with standard 2-jaw grippers, with one (or two) degrees of freedom. In this paper, an activity for designing and experimenting a gripper for this type of operations is reported, and the first laboratory results are presented and discussed. Main features of the gripper are its kinematic configuration (3 fingers with 3 dof) and its sensorial equipment, features that improve the dexterity of this device if compared to more classical devices
CARNITINE VERSUS ANDROGEN ADMINISTRATION IN THE TREATMENT OF SEXUAL DYSFUNCTION, DEPRESSED MOOD, AND FATIGUE ASSOCIATED WITH MALE AGING
No full textABSTRACT.
Objective. To determine whether the surgical straightening of congenital penile curvature can improve intromission comfort, penile features, personal relationships, and psychogenic erectile dysfunction (ED).
Materials and methods. 54 patients (mean age 24, range 20-31) whose congenital penile deviation from physiological curvature was ≥25° measured on a graph and induced penetration discomfort underwent an assessment carried out specifically for this study. 14 patients suffered from psychogenic ED. The assessment comprised: a case history, an objective examination, a pharmacologically-induced erection with prostaglandin E1 10-20 μcg, a graph taken during erection, a basal and dynamic Duplex ultrasonograph, penile length measurement, nocturnal penile tumescence recording, hormonal profiles and a psychological interview in order to evaluate the quality of their personal relationships according to Hinde’s parameters (contents, number, features, frequency, ability to perceive limits of mutuality, subjective perception of the other person(s), and reliability). All patients were submitted to the Nesbit procedure. The initial assessment was then repeated at 3 months and 12 months after surgery. Data analyses were carried out with the z test.
Results. Subjective judgement of cosmetic penile features and vaginal intromission comfort improved significantly after surgery, while the quality of personal relationships and ED did not.
Conclusions. The surgical straightening of congenital penile curvature improved intromission comfort and penile features, but it failed to improve personal relationship or psychogenic ED
Integration of robotic systems in a packaging machine: A tool for design and simulation of efficient motion trajectories
No full textIn this paper, the advantages of CACSD (Computer Aided Control System Design) tools for integrating a robotic system in a packaging machine are illustrated. Beside the mechanical integration of the robot into the machine architecture, it is necessary a functional integration, that requires a precise synchronization with the other parts of the system. In the proposed application, a robot with a parallel kinematics is used for pick-and-place tasks between two conveyor belts. It is therefore necessary a proper motion planning which allows to synchronize the grasp and release phases with the conveyor belts, avoiding obstacles and guaranteeing the compliance with bounds on velocity, acceleration and limits in the workspace. A trajectory composed by quintic polynomials has been considered and a specific tool has been designed in the Matlab environment, which allows to modify the parameters of the trajectory and to analyze the obtained motion profiles from both the kinematic and dynamic point of view
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