1,794 research outputs found

    Critical Steps of Plasmodium falciparum Ookinete Maturation

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    The egress and fertilization of Plasmodium gametes and development of a motile ookinete are the first crucial steps that mediate the successful transmission of the malaria parasites from humans to the Anopheles vector. However, limited information exists about the cell biology and regulation of this process. Technical impediments in the establishment of in vitro conditions for ookinete maturation in Plasmodium falciparum and other human malaria parasites further constrain a detailed characterization of ookinete maturation. Here, using fluorescence microscopy and immunolabeling, we compared P. falciparum ookinete maturation in Anopheles coluzzii mosquitoes in vivo and in cell culture in vitro. Our results identified two critical steps in ookinete maturation that are regulated by distinct mosquito factors, thereby highlighting the role of the mosquito environment in the transmission efficiency of malaria parasites

    Structural distinctions of Fe2O3-In2O3 composites obtained by various sol-gel procedures, and their gas-sensing features

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    New and various approaches to the sol–gel synthesis of advanced gas-sensing materials based on nanosized Fe2O3–In2O3 (9:1 mol) mixed oxides, which differ in phase composition and grain size, have been considered in this paper. The correlation between the structural features of the composites and their gas-sensing behavior has been established. It was found that multi-phase Fe2O3–In2O3 composites containing metastable -Fe2O3 structure are characterized by the greatest sensitivity to both reducing (C2H5OH) and oxidizing (NO2) gases tested in this paper. The influence of synthesis conditions on the structural peculiarities of the Fe2O3–In2O3 composites was studied in detail and the possibility to adjust fine structure of the materials was demonstrated

    A 177 ppm RMS Error-Integrated Interface for Time-Based Impedance Spectroscopy of Sensors

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    This paper presents an integrated circuit for time-based electrical impedance spectroscopy (EIS) of sensors. The circuit exploits maximum-length sequences (MLS) in order to perform a broadband excitation of the sensors under test. Therefore, the measured time-domain EIS is obtained by cross-correlating the input with the output of the analog front end (AFE). Unlike the conventional digital approach, the cross-correlation operation is performed in the analog domain. This leads to a lower RMS error in the measured time-domain EIS since the signal processing is not affected by the quantization noise of the analog-to-digital converter (ADC). It also relaxes the sampling frequency of the ADC leading, along with the lack of random access memory (RAM) usage, to a reduced circuit complexity. Theoretical concepts about the circuit’s design and operation are presented, with an emphasis on the thermal noise phenomenon. The simulated performances are shown by testing a sensor’s equivalent model composed of a 50 kΩ resistor in parallel with a 100 (Formula presented.) (Formula presented.) capacitor. A time-based EIS output of 255 points was obtained with a maximum tested frequency of 500 (Formula presented.) (Formula presented.) and a simulated RMS error of 0.0177% (or 177 ppm)

    Isolation of rat hepatocytes for pharmacological studies on metabotropic glutamate receptor (mGluR) subtype 5: a comparison between collagenase I versus collagenase IV.

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    Isolated hepatocytes can be obtained from the liver by collagenase infusion, a procedure that could affect cell isolation as well as the integrity of membrane receptors. In this respect we compared metabotropic glutamate subtype 5 receptor (mGluR5) protein expression and activity in rat hepatocytes isolated by two collagenases, type I and type IV. Hepatocytes were isolated from male Wistar rats (200-250 g) using collagenase I or colla-genase IV and after isolation, viability and morphology of rat hepatocytes were assessed measuring mGluR5 protein expression by Western blot analyses. mGluR5 activation was evaluated by inositol-1-phosphate (IP-1) accumulation after treatment with the mGluR5 orthosteric agonist ACPD or the selective antagonist MPEP. No difference in cellular viability and morphology was observed using collagenase I when compared with collage-nase IV. An increase in mGluR5 protein expression was observed in hepatocytes isolated using collagenase IV with respect to collagenase I. Moreover, hepatocytes treated with ACPD and with MPEP presented higher levels of IP-1 when isolated using collagenase IV compared tocollagenase I. These results indicate that collage-nase IV better preserves the activity of surface proteins such as mGluR5in isolated rat hepatocytes, an in vitro model useful to reduce the use of experimental animals, in line with the 3R ethical framework

    A Flexible Robotic Depalletizing System for Supermarket Logistics

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    Depalletizing robotic systems are commonly deployed to automatize and speed-up parts of logistic processes. Despite this, the necessity to adapt the preexisting logistic processes to the automatic systems often impairs the application of such robotic solutions to small business realities like supermarkets. In this work we propose a robotic depalletizing system designed to be easily integrated into supermarket logistic processes. The system has to schedule, monitor and adapt the depalletizing process considering both on-line perceptual information given by non-invasive sensors and constraints provided by the high-level management system or by a supervising user. We describe the overall system discussing two case studies in the context of a supermarket logistic process. We show how the proposed system can manage multiple depalletizing strategies and multiple logistic requests

    A Reconfigurable Gripper for Robotic Autonomous Depalletizing in Supermarket Logistics

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    Automatic depalletizing is becoming a practice widely applied in warehouses to automatize and speed-up logistics. On the other hand, the necessity to adapt the preexisting logistic lines to a custom automatic system can be a limit for the application of robotic solutions into smaller facilities like supermarkets. In this work, we tackle this issue by proposing a flexible and adaptive gripper for robotic depalletizing. The gripper is designed to be assembled on the end-tip of an industrial robotic arm. A novel patent-pending mechanism allows grasping boxes and products from both the upper and the lateral side enabling the depalletizing of boxes with complex shape. Moreover, the gripper is reconfigurable with five actuated degrees of freedom, that are automatically controlled using the embedded sensors to adapt grasping to different shapes and weights

    Total Cross Sections for Neutron Scattering

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    Measurements of neutron total cross-sections are both extensive and extremely accurate. Although they place a strong constraint on theoretically constructed models, there are relatively few comparisons of predictions with experiment. The total cross-sections for neutron scattering from 16^{16}O and 40^{40}Ca are calculated as a function of energy from 50−70050-700~MeV laboratory energy with a microscopic first order optical potential derived within the framework of the Watson expansion. Although these results are already in qualitative agreement with the data, the inclusion of medium corrections to the propagator is essential to correctly predict the energy dependence given by the experiment.Comment: 10 pages (Revtex 3.0), 6 fig

    RGB-D Recognition and Localization of Cases for Robotic Depalletizing in Supermarkets

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    Integrating a robotic system into the depalletizing process of a supermarket demands a high level of autonomy, based on strong perceptive capabilities. This letter presents a system for detection, recognition, and localization of heterogeneous cases in a depalletizing robotic cell, using a single RGB-D camera. Such a system integrates apriori information on the content of the pallet with data from the RGB-D camera, exploiting a sequence of 2D and 3D model-based computer-vision algorithms. The effectiveness of the proposed methodology is assessed in an experiment where multiple cases and pallet configurations are considered. Finally, a complete depalletizing process is shown
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