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  1. Circadian plasticity in photoreceptor cells controls visual coding efficiency in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Martin Barth

    Full Text Available In the fly Drosophila melanogaster, neuronal plasticity of synaptic terminals in the first optic neuropil, or lamina, depends on early visual experience within a critical period after eclosion. The current study revealed two additional and parallel mechanisms involved in this type of synaptic terminal plasticity. First, an endogenous circadian rhythm causes daily oscillations in the volume of photoreceptor cell terminals. Second, daily visual experience precisely modulates the circadian time course and amplitude of the volume oscillations that the photoreceptor-cell terminals undergo. Both mechanisms are separable in their molecular basis. We suggest that the described neuronal plasticity in Drosophila ensures continuous optimal performance of the visual system over the course of a 24 h-day. Moreover, the sensory system of Drosophila cannot only account for predictable, but also for acute, environmental changes. The volumetric changes in the synaptic terminals of photoreceptor cells are accompanied by circadian and light-induced changes of presynaptic ribbons as well as extensions of epithelial glial cells into the photoreceptor terminals, suggesting that the architecture of the lamina is altered by both visual exposure and the circadian clock. Clock-mutant analysis and the rescue of PER protein rhythmicity exclusively in all R1-6 cells revealed that photoreceptor-cell plasticity is autonomous and sufficient to control visual behavior. The strength of a visually guided behavior, the optomotor turning response, co-varies with synaptic-terminal volume oscillations of photoreceptor cells when elicited at low light levels. Our results show that behaviorally relevant adaptive processing of visual information is performed, in part, at the level of visual input level.

  2. Robot Visual Control

    OpenAIRE

    Chaumette, François

    2015-01-01

    This article describes the basic concepts of vision-based control, that is, the use of visual data to control the motions of a robotics system. It describes the modeling steps allowing the design of kinematics control schemes. Applications are also described.

  3. Robot Visual Control

    OpenAIRE

    Chaumette, François

    2015-01-01

    International audience This article describes the basic concepts of vision-based control, that is, the use of visual data to control the motions of a robotics system. It describes the modeling steps allowing the design of kinematics control schemes. Applications are also described.

  4. Visually Guided Control of Movement

    Science.gov (United States)

    Johnson, Walter W. (Editor); Kaiser, Mary K. (Editor)

    1991-01-01

    The papers given at an intensive, three-week workshop on visually guided control of movement are presented. The participants were researchers from academia, industry, and government, with backgrounds in visual perception, control theory, and rotorcraft operations. The papers included invited lectures and preliminary reports of research initiated during the workshop. Three major topics are addressed: extraction of environmental structure from motion; perception and control of self motion; and spatial orientation. Each topic is considered from both theoretical and applied perspectives. Implications for control and display are suggested.

  5. Control information in visual flight

    Science.gov (United States)

    Naish, J. M.

    1972-01-01

    The purpose of the inquiry is to determine how precisely a pilot can estimate the movements of his vehicle, and thus exercise control, during an unaided visual approach. The method is to relate changes in the forward view, due to movements along and across the approach path, to human visual thresholds and errors. The scope is restricted to effects of inclination, expansion, size, and rotation in runway features during approaches at small angles of elevation. Quantitative relations are given which provide a basis for ranking the several information mechanisms. Alignment by inclination of a ground line is found to be an accurate lateral mechanism, probably superior to the expansion mechanism. Vertical control mechanisms are complex, of questionable accuracy, and difficult to rank. The results throw some doubt on the usefulness of a runway symbol as a source of displayed information.

  6. Cloud-based Networked Visual Servo Control

    DEFF Research Database (Denmark)

    Wu, Haiyan; Lu, Lei; Chen, Chih-Chung;

    2013-01-01

    , which integrates networked computational resources for cloud image processing, is considered in this article. The main contributions of this article are i) a real-time transport protocol for transmitting large volume image data on a cloud computing platform, which enables high sampling rate visual......The performance of vision-based control systems, in particular of highly dynamic vision-based motion control systems, is often limited by the low sampling rate of the visual feedback caused by the long image processing time. In order to overcome this problem, the networked visual servo control...... feedback, ii) a stabilizing control law for the networked visual servo control system with time-varying feedback time delay, and iii) a sending rate scheduling strategy aiming at reducing the communication network load. The performance of the networked visual servo control system with sending rate...

  7. Visually guided control of self motion

    Science.gov (United States)

    Hettinger, Lawrence J.; Andersen, G. John; Flach, John M.; Riccio, Gary E.; Bennett, C. Thomas; Johnson, Walter W.

    1989-01-01

    A workshop entitled 'Visually Guided Control of Movement' was held at NASA Ames Research Center on June 26 - July 14, 1989. The workshop brought together individuals with diverse backgrounds related to the areas of the visual perception and control of motion. During the workshop, participants designed and conducted experiments using NASA Ames flight simulation research facilities. These studies contrasted participants' alternative theoretical approaches to the visual control of self motion. Panel members, drawn from the workshop's participants, will discuss their approaches to the study of the control of self motion and will present interpretations of the outcomes of the workshop.

  8. Training Visual Control in Wheelchair Basketball Shooting

    Science.gov (United States)

    Oudejans, Raoul R. D.; Heubers, Sjoerd; Ruitenbeek, Jean-Rene J. A. C.; Janssen, Thomas W. J.

    2012-01-01

    We examined the effects of visual control training on expert wheelchair basketball shooting, a skill more difficult than in regular basketball, as players shoot from a seated position to the same rim height. The training consisted of shooting with a visual constraint that forced participants to use target information as late as possible.…

  9. Visualization for cyber security command and control

    Science.gov (United States)

    Langton, John T.; Newey, Brent; Havig, Paul R.

    2010-04-01

    To address the unique requirements of cyber Command and Control (C2), new visualization methods are needed to provide situation awareness and decision support within the cyber domain. A key challenge is the complexity of relevant data: it is immense and multidimensional, includes streaming and log data, and comes from multiple, disparate applications and devices. Decision makers must be afforded a view of a) the current state of the cyber battlespace, b) enemy and friendly capabilities and vulnerabilities, c) correlations between cyber events, and d) potential effects of alternative courses of action within cyberspace. In this paper we present requirements and designs for Visualization for Integrated Cyber Command and Control (VIC3).

  10. Neural Network Controlled Visual Saccades

    Science.gov (United States)

    Johnson, Jeffrey D.; Grogan, Timothy A.

    1989-03-01

    The paper to be presented will discuss research on a computer vision system controlled by a neural network capable of learning through classical (Pavlovian) conditioning. Through the use of unconditional stimuli (reward and punishment) the system will develop scan patterns of eye saccades necessary to differentiate and recognize members of an input set. By foveating only those portions of the input image that the system has found to be necessary for recognition the drawback of computational explosion as the size of the input image grows is avoided. The model incorporates many features found in animal vision systems, and is governed by understandable and modifiable behavior patterns similar to those reported by Pavlov in his classic study. These behavioral patterns are a result of a neuronal model, used in the network, explicitly designed to reproduce this behavior.

  11. Visual cortex controls retinal output in the rat.

    Science.gov (United States)

    Molotchnikoff, S; Tremblay, F

    1986-07-01

    The first objective of the present investigation was to shed more light on corticofugal influences on the retina by providing an analysis of the type and proportion of retinal ganglion cells that are affected by cooling the visual cortex in rats. The second question was to determine if the pretectum participates in functional cortico-retinal relationships. In urethane-anesthetized and paralyzed hooded rats, axonal activity of retinal ganglion cells was recorded with glass micropipettes at optic chiasm level. Units were classified as ON, OFF, suppressed-by-light and concentric. The visual cortex was inactivated by cooling its surface with a 4 mm2 steel probe using the Peltier effect. The pretectum was blocked with microinjections of 50 to 100 nanoliters of cobalt ions, lidocaine hydrochloride or KCl. The inactivations and recoveries at both sites were monitored by simultaneously recording evoked field potentials. Interrupting corticofugal impulses caused modifications of the evoked discharge pattern in all types of cells. The concentric type was the group least affected by cortical cooling. A common trend emerged suggesting that cooling of the visual cortex led to an enhancement of the initial evoked excitation. This was often followed by an enhanced post-excitatory inhibition. The Pearson coefficient allowed us to measure the degree of similarity between two histograms. When all data were pooled, a weak correlation between control and test histograms (r = 0.29, N = 56) was found, while the control and recovery patterns averaged a correlation of more than twice that size (r = 0.68). In a second series of experiments, the pretectum and visual cortex (VC) were simultaneously inactivated. It is shown that both sites summed their influence and acted synergistically upon the pattern of ganglion cell responses. The results strongly suggest that the visual cortex exerts a major control over the response pattern of thirty percent of retinal ganglion cells, and that the

  12. Cooperative control of visual displays for telemanipulation

    Science.gov (United States)

    Kim, Won S.; Stark, Lawrence W.

    1989-01-01

    Two cooperative control schemes for telerobot visual displays are addressed. In the first scheme, on-the-screen visual enhancements such as reference lines indicating the vertical height of the robot hand, a stick figure model of the robot hand, and its projection on the horizontal grid plane are constructed by the interactive cooperation between the human operator and the telerobotic system, and then superimposed on the video screen. Experimental results with a five-degree-of-freedom robot and a frame grabber indicate that superimposition of visual enhancements on the video screen greatly improves telemanipulation task performance. In the second scheme, the position and orientation of an object on video screens are determined interactively; these then assist the telerobotic system in executing the human operator's task-level commands autonomously.

  13. Visualizing cell state transition using Raman spectroscopy.

    Directory of Open Access Journals (Sweden)

    Taro Ichimura

    Full Text Available System level understanding of the cell requires detailed description of the cell state, which is often characterized by the expression levels of proteins. However, understanding the cell state requires comprehensive information of the cell, which is usually obtained from a large number of cells and their disruption. In this study, we used Raman spectroscopy, which can report changes in the cell state without introducing any label, as a non-invasive method with single cell capability. Significant differences in Raman spectra were observed at the levels of both the cytosol and nucleus in different cell-lines from mouse, indicating that Raman spectra reflect differences in the cell state. Difference in cell state was observed before and after the induction of differentiation in neuroblastoma and adipocytes, showing that Raman spectra can detect subtle changes in the cell state. Cell state transitions during embryonic stem cell (ESC differentiation were visualized when Raman spectroscopy was coupled with principal component analysis (PCA, which showed gradual transition in the cell states during differentiation. Detailed analysis showed that the diversity between cells are large in undifferentiated ESC and in mesenchymal stem cells compared with terminally differentiated cells, implying that the cell state in stem cells stochastically fluctuates during the self-renewal process. The present study strongly indicates that Raman spectral morphology, in combination with PCA, can be used to establish cells' fingerprints, which can be useful for distinguishing and identifying different cellular states.

  14. Reward and Attentional Control in Visual Search

    OpenAIRE

    Yantis, Steven; Anderson, Brian A.; Wampler, Emma K.; Laurent, Patryk A.

    2012-01-01

    It has long been known that the control of attention in visual search depends both on voluntary, top-down deployment according to context-specific goals, and on involuntary, stimulus-driven capture based on the physical conspicuity of perceptual objects. Recent evidence suggests that pairing target stimuli with reward can modulate the voluntary deployment of attention, but there is little evidence that reward modulates the involuntary deployment of attention to task-irrelevant distractors. We...

  15. Visualization of DNA damage in individual cells

    International Nuclear Information System (INIS)

    A simple technique of micro-agarose gel electrophoresis has been developed to permit an evaluation of DNA damage in individual cells. Cells are embeded in agarose gel on microscope slides, lysed by detergents and then electrophoresed for a short time. In damaged cells, DNA migrated from the nuclei toward the anode, displaying 'comets' visualized by staining with a DNA-specific fluorochrome, acridine orange. The technique was applicable to quantifying DNA damage in individual cells exposed to Gy level of reactor radiation. (author)

  16. Visual Control of Robots Using Range Images

    Directory of Open Access Journals (Sweden)

    Fernando Torres

    2010-08-01

    Full Text Available In the last years, 3D-vision systems based on the time-of-flight (ToF principle have gained more importance in order to obtain 3D information from the workspace. In this paper, an analysis of the use of 3D ToF cameras to guide a robot arm is performed. To do so, an adaptive method to simultaneous visual servo control and camera calibration is presented. Using this method a robot arm is guided by using range information obtained from a ToF camera. Furthermore, the self-calibration method obtains the adequate integration time to be used by the range camera in order to precisely determine the depth information.

  17. Cholinergic control of visual categorization in macaques.

    Science.gov (United States)

    Aggelopoulos, Nikolaos C; Liebe, Stefanie; Logothetis, Nikos K; Rainer, Gregor

    2011-01-01

    Acetylcholine (ACh) is a neurotransmitter acting via muscarinic and nicotinic receptors that is implicated in several cognitive functions and impairments, such as Alzheimer's disease. It is believed to especially affect the acquisition of new information, which is particularly important when behavior needs to be adapted to new situations and to novel sensory events. Categorization, the process of assigning stimuli to a category, is a cognitive function that also involves information acquisition. The role of ACh on categorization has not been previously studied. We have examined the effects of scopolamine, an antagonist of muscarinic ACh receptors, on visual categorization in macaque monkeys using familiar and novel stimuli. When the peripheral effects of scopolamine on the parasympathetic nervous system were controlled for, categorization performance was disrupted following systemic injections of scopolamine. This impairment was observed only when the stimuli that needed to be categorized had not been seen before. In other words, the monkeys were not impaired by the central action of scopolamine in categorizing a set of familiar stimuli (stimuli which they had categorized successfully in previous sessions). Categorization performance also deteriorated as the stimulus became less salient by an increase in the level of visual noise. However, scopolamine did not cause additional performance disruptions for difficult categorization judgments at lower coherence levels. Scopolamine, therefore, specifically affects the assignment of new exemplars to established cognitive categories, presumably by impairing the processing of novel information. Since we did not find an effect of scopolamine in the categorization of familiar stimuli, scopolamine had no significant central action on other cognitive functions such as perception, attention, memory, or executive control within the context of our categorization task. PMID:22110428

  18. Cholinergic control of visual categorisation in macaques

    Directory of Open Access Journals (Sweden)

    Nikolaos C. Aggelopoulos

    2011-11-01

    Full Text Available Acetylcholine (ACh is a neurotransmitter acting via muscarinic and nicotinic receptors that is implicated in several cognitive functions and impairments, such as Alzheimer’s disease. It is believed to especially affect the acquisition of new information, which is particularly important when behaviour needs to be adapted to new situations and to novel sensory events. Categorisation, the process of assigning stimuli to a category, is a cognitive function that also involves information acquisition. The role of ACh on categorisation has not been previously studied. We have examined the effects of scopolamine, an antagonist of muscarinic ACh receptors, on visual categorisation in macaque monkeys using familiar and novel stimuli. When the peripheral effects of scopolamine on the parasympathetic nervous system were controlled for, categorisation performance was disrupted following systemic injections of scopolamine. This impairment was observed only when the stimuli that needed to be categorised had not been seen before. In other words, the monkeys were not impaired by the central action of scopolamine in categorising a set of familiar stimuli (stimuli which they had categorised successfully in previous sessions. Categorisation performance also deteriorated as the stimulus became less salient by an increase in the level of visual noise. However, scopolamine did not cause additional performance disruptions for difficult categorisation judgements at lower coherence levels. Scopolamine, therefore, specifically affects the assignment of new exemplars to established cognitive categories, presumably by impairing the processing of novel information. Since we did not find an effect of scopolamine in the categorisation of familiar stimuli, scopolamine had no significant central action on other cognitive functions such as perception, attention, memory or executive control within the context of our categorisation task.

  19. Experimental consideration for realizing image based visual servo control system

    International Nuclear Information System (INIS)

    In this study, we consider the experimental aspect of image based visual servo control system. The items considered are the following; 1) Inertial parameter estimation, 2) Focal point estimation, 3) Controller performance for the system with delay. From the experimental result of visual control, it is found that the system is very sensitive to the controller gain because of the computational delay of vision. In order to establish a satisfactory delay compensation, more investigations on controller design are required. (author)

  20. Hummingbirds control hovering flight by stabilizing visual motion

    OpenAIRE

    Goller, Benjamin; Altshuler, Douglas L.

    2014-01-01

    The avian brain has numerous specializations for navigation and processing visual information, but relatively little is known about how flying birds control their position in space. To study the role of vision in controlling hovering flight, we developed a virtual reality environment where visual patterns could be displayed to a freely flying hummingbird. Normal flight could only be performed if the visual background was completely stationary. In contrast, any motion in the background image c...

  1. Cell control report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This extensive report provides an essential overview of cells and their use as factory automation building blocks. The following issues are discussed in depth: Cell integration Cell software and standards Future technologies applied to cells Plus Cell control applications including: - rotary parts manufacturing - diesel engine component development - general cell control development at the General Electric Corporation - a vendor list.

  2. Clock and clock-controlled genes are differently expressed in the retina, lamina and in selected cells of the visual system of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Milena eDamulewicz

    2015-09-01

    Full Text Available The retina and the first optic neuropil (lamina of Drosophila show circadian rhythms in various processes. To learn about the regulation of circadian rhythms in the retina and lamina and in two cell types, glial and the lamina L2 interneurons, we examined expression of the following clock genes; per, tim, clk, and cry and clock-controlled genes; Atp, nrv2, brp, Pdfr. We found that the expression of gene studied is specific for the retina and lamina. The rhythms of per and tim expression in the retina and glial cells are similar to that observed in the whole head and in clock neurons, while they differ in the lamina and L2 cells. In both the retina and lamina, CRY seems to be a repressor of clk expression. In L2 interneurons per expression is not cyclic indicating the other function of PER in those cells than in the circadian molecular clock. In contrast to per and tim, the pattern of clk and cry expression is similar in both the retina and lamina. The retina holds the autonomous oscillators but the expression of cry and clock-controlled genes, Atp and nrv2, is also regulated by inputs from the pacemaker transmitted by PDF and ITP neuropeptides.

  3. A visual AGV-urban car using Fuzzy control

    OpenAIRE

    Olivares Méndez, Miguel Ángel; Mellado Bataller, Ignacio; Campoy Cervera, Pascual; Mondragon Bernal, Ivan Fernando; Martínez Luna, Carol Viviana

    2011-01-01

    The goal of the work described in this paper is to develop a visual line guided system for being used on-board an Autonomous Guided Vehicle (AGV) commercial car, controlling the steering and using just the visual information of a line painted below the car. In order to implement the control of the vehicle, a Fuzzy Logic controller has been implemented, that has to be robust against curvature changes and velocity changes. The only input information for the controller is th...

  4. Visual Features Involving Motion Seen from Airport Control Towers

    Science.gov (United States)

    Ellis, Stephen R.; Liston, Dorion

    2010-01-01

    Visual motion cues are used by tower controllers to support both visual and anticipated separation. Some of these cues are tabulated as part of the overall set of visual features used in towers to separate aircraft. An initial analyses of one motion cue, landing deceleration, is provided as a basis for evaluating how controllers detect and use it for spacing aircraft on or near the surface. Understanding cues like it will help determine if they can be safely used in a remote/virtual tower in which their presentation may be visually degraded.

  5. Visual Servoed Three-Dimensional Cell Rotation System.

    Science.gov (United States)

    Wang, Zenan; Latt, Win Tun; Tan, Steven Yih Min; Ang, Wei Tech

    2015-10-01

    Three-dimensional (3-D) positioning and orientation of embryos/oocytes is necessary to facilitate micromanipulation tasks such as cell injection and cellular structural biopsy commonly performed under a microscope. Conventional cell orientation is performed manually by using a vacuum equipped micropipette to aspirate and release the cell, which is a trial-and-error approach. The conventional method relies heavily on the skill of the operator; it also suffers from low precision, low success rate and low controllability. These drawbacks illustrate the need for a systematic 3-D cell rotational system to automate the cell orientation process. In this paper, we present a noninvasive single cell rotation system that can automatically orientate a zebrafish embryo to a desired position when both the cytoplasm and the yolk are in the focal plane. A three-point-contact model for cell rotation that involves a custom-designed rotational stage is introduced to provide precise rotational position control. A vision recognition algorithm is also proposed to enable the visual servoing function of the system. Experimental results show that the proposed system can achieve high success rates of 92.5% (x-axis rotation with 40 trails) and 97.5% (about the z-axis with 80 trails). The system can also successfully complete 3-D cell orientation at an average speed of 31 s/cell with a high in-plane rotation accuracy of 0.3 (°) . As a high precise, high controllable and deterministic cell manipulating system, it provides a starting point for automated cell manipulation for intracytoplasmic sperm injection and embryo biopsy for preimplantation genetic diagnosis. PMID:25993702

  6. Clock and clock-controlled genes are differently expressed in the retina, lamina and in selected cells of the visual system of Drosophila melanogaster

    OpenAIRE

    Milena eDamulewicz; Agnieszka eLoboda; Karolina eBukowska-Strakova; Alicja eJozkowicz; Jozef eDulak; Elzbieta M Pyza

    2015-01-01

    The retina and the first optic neuropil (lamina) of Drosophila show circadian rhythms in various processes. To learn about the regulation of circadian rhythms in the retina and lamina and in two cell types, glial and the lamina L2 interneurons, we examined expression of the following clock genes; per, tim, clk, and cry and clock-controlled genes; Atp, nrv2, brp, Pdfr. We found that the expression of gene studied is specific for the retina and lamina. The rhythms of per and tim expression in...

  7. A hybrid Jacobian control for uncalibrated robot visual servoing

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qizhi; GE Xinsheng; TEO Chee-Leong; LIM Siak-Piang

    2005-01-01

    This paper focuses on the visual servo control of an uncalibrated robotic arm with an eye-in-hand camera. Without a prior knowledge of the kinematics of the robotic arm or camera calibration, the proposed hybrid Jacobian controller can track a moving object using visual feedback and joint-space velocity feedback. The proposed hybrid control method is a combination of the uncalibrated visual servoing and approximate Jacobian feedback control. First, the Jacobian matrix from joint-space to image-space is estimated by recursive leastsquares (RLS) algorithm, and then the approximate Jacobian feedback controller is designed by using visual feedback and joint-space velocity feedback. The performances of the proposed control methods are illustrated by computer simulations.

  8. Proprioceptive versus Visual Control in Autistic Children.

    Science.gov (United States)

    Masterton, B. A.; Biederman, G. B.

    1983-01-01

    The autistic children's presumed preference for proximal over distal sensory input was studied by requiring that "autistic," retarded, and "normal" children (7-15 years old) adapt to lateral displacement of the visual field. Only autistic Ss demonstrated transfer of adaptation to the nonadapted hand, indicating reliance on proprioception rather…

  9. Seeing Cells: Teaching the Visual/Verbal Rhetoric of Biology

    Science.gov (United States)

    Dinolfo, John; Heifferon, Barbara; Temesvari, Lesly A.

    2007-01-01

    This pilot study obtained baseline information on verbal and visual rhetorics to teach microscopy techniques to college biology majors. We presented cell images to students in cell biology and biology writing classes and then asked them to identify textual, verbal, and visual cues that support microscopy learning. Survey responses suggest that…

  10. Visualizing Without Vision at the Microscale: Students With Visual Impairments Explore Cells With Touch

    Science.gov (United States)

    Jones, M. Gail; Minogue, James; Oppewal, Tom; Cook, Michelle P.; Broadwell, Bethany

    2006-12-01

    Science instruction is typically highly dependent on visual representations of scientific concepts that are communicated through textbooks, teacher presentations, and computer-based multimedia materials. Little is known about how students with visual impairments access and interpret these types of visually-dependent instructional materials. This study explored the efficacy of new haptic (simulated tactile feedback and kinesthetics) instructional technology for teaching cell morphology and function to middle and high school students with visual impairments. The study examined students' prior experiences learning about the cell and cell functions in classroom instruction, as well as how haptic feedback technology impacted students' awareness of the 3-D nature of an animal cell, the morphology and function of cell organelles, and students' interest in the haptic technology as an instructional tool. Twenty-one students with visual impairment participated in the study. Students explored a tactile model of the cell with a haptic point probe that allowed them to feel the cell and its organelles. Results showed that students made significant gains in their ability to identify cell organelles and found the technology to be highly interesting as an instructional tool. The need for additional adaptive technology for students with visual impairments is discussed.

  11. Patient DF's visual brain in action: Visual feedforward control in visual form agnosia.

    Science.gov (United States)

    Whitwell, Robert L; Milner, A David; Cavina-Pratesi, Cristiana; Barat, Masihullah; Goodale, Melvyn A

    2015-05-01

    Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it is possible that it may rely abnormally on online visual or haptic feedback. We report here that DF's grip scaling remained intact when her vision was completely suppressed during grasp movements, and it still dissociated sharply from her poor perceptual estimates of target size. We then tested whether providing trial-by-trial haptic feedback after making such perceptual estimates might improve DF's performance, but found that they remained significantly impaired. In a final experiment, we re-examined whether DF's grip scaling depends on receiving veridical haptic feedback during grasping. In one condition, the haptic feedback was identical to the visual targets. In a second condition, the haptic feedback was of a constant intermediate width while the visual target varied trial by trial. Despite this incongruent feedback, DF still scaled her grip aperture to the visual widths of the target blocks, showing only normal adaptation to the false haptically-experienced width. Taken together, these results strengthen the view that DF's spared grasping relies on a normal mode of dorsal-stream functioning, based chiefly on visual feedforward processing. PMID:25199609

  12. Cell Control Engineering

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1996-01-01

    The engineering process of creating cell control systems is described, and a Cell Control Engineering (CCE) concept is defined. The purpose is to assist people, representing different disciplines in the organisation, to implement cell controllers by addressing the complexity of having many systems...... in physically and logically different and changing manufacturing environments. The defined CCE concept combines state-of-the-art of commercially available enabling technologies for automation system software development, generic cell control models and guidelines for the complete engineering process....... It facilitates the understanding of the task and structure of cell controllers and uses this knowledge directly in the implementation of the system. By applying generic models CCE facilitates reuse of software components and maintenance of applications. In many enterprises, software makes up an...

  13. From grid cells and visual place cells to multimodal place cell: a new robotic architecture.

    Science.gov (United States)

    Jauffret, Adrien; Cuperlier, Nicolas; Gaussier, Philippe

    2015-01-01

    In the present study, a new architecture for the generation of grid cells (GC) was implemented on a real robot. In order to test this model a simple place cell (PC) model merging visual PC activity and GC was developed. GC were first built from a simple "several to one" projection (similar to a modulo operation) performed on a neural field coding for path integration (PI). Robotics experiments raised several practical and theoretical issues. To limit the important angular drift of PI, head direction information was introduced in addition to the robot proprioceptive signal coming from the wheel rotation. Next, a simple associative learning between visual place cells and the neural field coding for the PI has been used to recalibrate the PI and to limit its drift. Finally, the parameters controlling the shape of the PC built from the GC have been studied. Increasing the number of GC obviously improves the shape of the resulting place field. Yet, other parameters such as the discretization factor of PI or the lateral interactions between GC can have an important impact on the place field quality and avoid the need of a very large number of GC. In conclusion, our results show our GC model based on the compression of PI is congruent with neurobiological studies made on rodent. GC firing patterns can be the result of a modulo transformation of PI information. We argue that such a transformation may be a general property of the connectivity from the cortex to the entorhinal cortex. Our model predicts that the effect of similar transformations on other kinds of sensory information (visual, tactile, auditory, etc…) in the entorhinal cortex should be observed. Consequently, a given EC cell should react to non-contiguous input configurations in non-spatial conditions according to the projection from its different inputs. PMID:25904862

  14. Predictive Control for Visual Servo Stabilization of Nonholonomic Mobile Robots

    Institute of Scientific and Technical Information of China (English)

    CAO Zheng-Cai; YIN Long-Jie; FU Yi-Li; LIU Tian-Long

    2013-01-01

    Visual servo stabilization of nonholonomic mobile robots has gained extensive attention.However,currently,the solution of the problem does not consider both the visibility constraints and the actuator limitations,so the designed controller is difficult to realize satisfactory performance in practical application.In this paper,a predictive controller for the visual servo stabilization of a mobile robot is presented.Firstly,a kinematic predictive stabilization controller utilized to generate the command of velocity is introduced.Then,in order to make the actual velocity of the mobile robot asymptotically approach to the desired one,a dynamic predictive controller is designed.The proposed predictive controller can deal with the constraints easily.Finally,several simulations are performed,and the results illustrate that the proposed control scheme is effective to solve the visual servo stabilization problem.

  15. Closed-Loop Learning of Visual Control Policies

    CERN Document Server

    Jodogne, S R; 10.1613/jair.2110

    2011-01-01

    In this paper we present a general, flexible framework for learning mappings from images to actions by interacting with the environment. The basic idea is to introduce a feature-based image classifier in front of a reinforcement learning algorithm. The classifier partitions the visual space according to the presence or absence of few highly informative local descriptors that are incrementally selected in a sequence of attempts to remove perceptual aliasing. We also address the problem of fighting overfitting in such a greedy algorithm. Finally, we show how high-level visual features can be generated when the power of local descriptors is insufficient for completely disambiguating the aliased states. This is done by building a hierarchy of composite features that consist of recursive spatial combinations of visual features. We demonstrate the efficacy of our algorithms by solving three visual navigation tasks and a visual version of the classical Car on the Hill control problem.

  16. The visual control of simulated altitude

    Science.gov (United States)

    Johnson, Walter W.; Bennett, C. Thomas; Tsang, Pamela S.; Phatak, Anil V.

    1987-01-01

    The ability of a subject flying an experimental flight to use the different sources of visual information by looking at the vertical tracking error was investigated using a 3 (altitude) x 3 (texture) x 2 (replication) factorial design. Each subject flew these 18 flights in the same partially counterbalanced order, constructed such that there was one flight at each of the three altitudes, and over each of the three surface textures within each successive set of three flights. The three ground-surface textures used consisted of meridian, latitudinal, and square textures described by Wolpert et al. (1983). The results showed that, in displays where only splay information was available, the subjects tended to confuse lateral motion with vertical.

  17. Patient DF's visual brain in action : visual feedforward control in patient with visual form agnosia.

    OpenAIRE

    Whitwell, R.L.; Milner, A D; Cavina-Pratesi, C.; Barat, M.; Goodale, M. A.

    2015-01-01

    Patient DF, who developed visual form agnosia following ventral-stream damage, is unable to discriminate the width of objects, performing at chance, for example, when asked to open her thumb and forefinger a matching amount. Remarkably, however, DF adjusts her hand aperture to accommodate the width of objects when reaching out to pick them up (grip scaling). While this spared ability to grasp objects is presumed to be mediated by visuomotor modules in her relatively intact dorsal stream, it i...

  18. Visualization of RNA-Quadruplexes in Live Cells.

    Science.gov (United States)

    Laguerre, Aurélien; Hukezalie, Kyle; Winckler, Pascale; Katranji, Fares; Chanteloup, Gaëtan; Pirrotta, Marc; Perrier-Cornet, Jean-Marie; Wong, Judy M Y; Monchaud, David

    2015-07-01

    Visualization of DNA and RNA quadruplex formation in human cells was demonstrated recently with different quadruplex-specific antibodies. Despite the significant interest in these immunodetection approaches, dynamic detection of quadruplex in live cells remains elusive. Here, we report on NaphthoTASQ (N-TASQ), a next-generation quadruplex ligand that acts as a multiphoton turn-on fluorescent probe. Single-step incubation of human and mouse cells with N-TASQ enables the direct detection of RNA-quadruplexes in untreated cells (no fixation, permeabilization or mounting steps), thus offering a unique, unbiased visualization of quadruplexes in live cells. PMID:26056849

  19. Design, Control and in Situ Visualization of Gas Nitriding Processes

    OpenAIRE

    Jerzy Ratajski; Roman Olik; Tomasz Suszko; Jerzy Dobrodziej; Jerzy Michalski

    2009-01-01

    The article presents a complex system of design, in situ visualization and control of the commonly used surface treatment process: the gas nitriding process. In the computer design conception, analytical mathematical models and artificial intelligence methods were used. As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of tim...

  20. The use of visual cues for vehicle control and navigation

    Science.gov (United States)

    Hart, Sandra G.; Battiste, Vernol

    1991-01-01

    At least three levels of control are required to operate most vehicles: (1) inner-loop control to counteract the momentary effects of disturbances on vehicle position; (2) intermittent maneuvers to avoid obstacles, and (3) outer-loop control to maintain a planned route. Operators monitor dynamic optical relationships in their immediate surroundings to estimate momentary changes in forward, lateral, and vertical position, rates of change in speed and direction of motion, and distance from obstacles. The process of searching the external scene to find landmarks (for navigation) is intermittent and deliberate, while monitoring and responding to subtle changes in the visual scene (for vehicle control) is relatively continuous and 'automatic'. However, since operators may perform both tasks simultaneously, the dynamic optical cues available for a vehicle control task may be determined by the operator's direction of gaze for wayfinding. An attempt to relate the visual processes involved in vehicle control and wayfinding is presented. The frames of reference and information used by different operators (e.g., automobile drivers, airline pilots, and helicopter pilots) are reviewed with particular emphasis on the special problems encountered by helicopter pilots flying nap of the earth (NOE). The goal of this overview is to describe the context within which different vehicle control tasks are performed and to suggest ways in which the use of visual cues for geographical orientation might influence visually guided control activities.

  1. Control of Fuel Cells

    OpenAIRE

    ZENITH, Federico

    2007-01-01

    This thesis deals with control of fuel cells, focusing on high-temperature proton-exchange-membrane fuel cells. Fuel cells are devices that convert the chemical energy of hydrogen, methanol or other chemical compounds directly into electricity, without combustion or thermal cycles. They are efficient, scalable and silent devices that can provide power to a wide variety of utilities, from portable electronics to vehicles, to nation-wide electric grids. Whereas studies about the design of fuel ...

  2. Control of Fuel Cells

    OpenAIRE

    ZENITH, Federico

    2007-01-01

    This thesis deals with control of fuel cells, focusing on high-temperature proton-exchange-membrane fuel cells.Fuel cells are devices that convert the chemical energy of hydrogen, methanol or other chemical compounds directly into electricity, without combustion or thermal cycles. They are efficient, scalable and silent devices that can provide power to a wide variety of utilities, from portable electronics to vehicles, to nation-wide electric grids.Whereas studies about the design of fuel ce...

  3. Atypical visual loss in giant cell arteritis

    DEFF Research Database (Denmark)

    Thystrup, Jan Deichmann; Knudsen, G M; Mogensen, A M;

    1994-01-01

    terminal stage of his disease due to bilateral occipital cortex infarctions, verified by CT-scan. Autopsy revealed involvement of several intracranial arteries. In case No. 2 there was severe unilateral visual loss and cotton-wool exudates in both eyes. Central vision recovered after corticosteroid therapy...

  4. Robot motion control from a visual memory

    OpenAIRE

    Remazeilles, A.; Chaumette, François; Gros, Patrick

    2004-01-01

    International audience This article presents a new approach for robot motion control, using images acquired by an on-board camera. A particularity of this method is that it can avoid reconstructing the entire scene without limiting the displacements possible. To achieve this, an image base of the environment is used to describe the navigation space. We extract from this base a sequence of overlapping images which define the zone that the robot must traverse, in order to reach the desired p...

  5. A case-control study of visual acuity in onychocryptosis.

    LENUS (Irish Health Repository)

    Hogan, Aisling M

    2012-02-01

    BACKGROUND: There are many theories surrounding the etiology of ingrown toenails (IGTN). Few factors have been formally assessed, but it is widely accepted that a poor nail cutting technique has a causative role. AIM: To investigate the hypothesis that decreased visual acuity may lead to inadequate nail cutting and the formation of IGTN. METHODS: A prospective case-control study was performed. Near and distance visual acuity were tested on a population with IGTN (n = 19) and compared with that of an age- and sex-matched control cohort (n = 24) who underwent epidermal cyst excision in the same tertiary referral center. Comparisons of visual acuity were made between groups by Mann-Whitney U-test. Differences were taken to be significant if P < 0.05. Institutional Review Board approval was sought and granted. RESULTS: No significant difference in visual acuity (near or distance) was demonstrated between patients with IGTN and the control group (P = 0.33). CONCLUSION: Visual acuity does not appear to play a significant role in the development of IGTN.

  6. The Effect of Concurrent Visual Feedback on Controlling Swimming Speed

    Directory of Open Access Journals (Sweden)

    Szczepan Stefan

    2016-03-01

    Full Text Available Introduction. Developing the ability to control the speed of swimming is an important part of swimming training. Maintaining a defined constant speed makes it possible for the athlete to swim economically at a low physiological cost. The aim of this study was to determine the effect of concurrent visual feedback transmitted by the Leader device on the control of swimming speed in a single exercise test. Material and methods. The study involved a group of expert swimmers (n = 20. Prior to the experiment, the race time for the 100 m distance was determined for each of the participants. In the experiment, the participants swam the distance of 100 m without feedback and with visual feedback. In both variants, the task of the participants was to swim the test distance in a time as close as possible to the time designated prior to the experiment. In the first version of the experiment (without feedback, the participants swam the test distance without receiving real-time feedback on their swimming speed. In the second version (with visual feedback, the participants followed a beam of light moving across the bottom of the swimming pool, generated by the Leader device. Results. During swimming with visual feedback, the 100 m race time was significantly closer to the time designated. The difference between the pre-determined time and the time obtained was significantly statistically lower during swimming with visual feedback (p = 0.00002. Conclusions. Concurrently transmitting visual feedback to athletes improves their control of swimming speed. The Leader device has proven useful in controlling swimming speed.

  7. Both visual and idiothetic cues contribute to head direction cell stability during navigation along complex routes

    OpenAIRE

    Yoder, Ryan M.; Clark, Benjamin J.; Brown, Joel E.; Lamia, Mignon V.; Valerio, Stephane; Shinder, Michael E.; Taube, Jeffrey S.

    2011-01-01

    Successful navigation requires a constantly updated neural representation of directional heading, which is conveyed by head direction (HD) cells. The HD signal is predominantly controlled by visual landmarks, but when familiar landmarks are unavailable, self-motion cues are able to control the HD signal via path integration. Previous studies of the relationship between HD cell activity and path integration have been limited to two or more arenas located in the same room, a drawback for interp...

  8. Visualization of information display at main control room

    International Nuclear Information System (INIS)

    An advanced main control room is planned for the next generation of nuclear power plants in Korea. Display devices such as LDP(Large Display Panel) and CRTs(Cathode Ray Tubes) are going to be utilized in that control room. Operating staff would have to perform tasks by monitoring displayed information about overall plant situation, subsystems, equipments, and components. However, if operators work with these new types of HMI(Human-Machine Interface), there are a lot of chances for unexperienced cognitive problems. Therefore, the designers of HMI should consider not only the information to be represented on display devices, but also visual information processing by operators and their cognitive limitations during information processing. This study reviews human's visual information processing process, classify information to be represented on display devices at the advanced control room, and possible representation formats for the classified information. We hope that the evaluation of HMI at the advanced control room would consider the result of this study

  9. Visually aided force control with fuzzy parameter tuning

    OpenAIRE

    Çallı, Berk; Calli, Berk; ERBATUR, Kemalettin; Ünel, Mustafa; Unel, Mustafa

    2009-01-01

    Vision and force sensors provide rich information which can enable robots to execute complex tasks. However, the integration of these two different types of sensors is not a trivial task. This paper provides a novel technique for the integration of vision and force information. Visual servoing and explicit force control techniques are applied in the task frame formalism. Disadvantages of the constant parameter controllers are addressed and a solution based on fuzzy tuning rules is proposed. T...

  10. Design, Control and in Situ Visualization of Gas Nitriding Processes

    Directory of Open Access Journals (Sweden)

    Jerzy Ratajski

    2009-12-01

    Full Text Available The article presents a complex system of design, in situ visualization and control of the commonly used surface treatment process: the gas nitriding process. In the computer design conception, analytical mathematical models and artificial intelligence methods were used. As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of time, as well as possibilities to predict the properties of nitrided layers. For in situ visualization of the growth of the nitrided layer, computer procedures were developed which make use of the results of the correlations of direct and differential voltage and time runs of the process result sensor (magnetic sensor, with the proper layer growth stage. Computer procedures make it possible to combine, in the duration of the process, the registered voltage and time runs with the models of the process.

  11. Design, control and in situ visualization of gas nitriding processes.

    Science.gov (United States)

    Ratajski, Jerzy; Olik, Roman; Suszko, Tomasz; Dobrodziej, Jerzy; Michalski, Jerzy

    2010-01-01

    The article presents a complex system of design, in situ visualization and control of the commonly used surface treatment process: the gas nitriding process. In the computer design conception, analytical mathematical models and artificial intelligence methods were used. As a result, possibilities were obtained of the poly-optimization and poly-parametric simulations of the course of the process combined with a visualization of the value changes of the process parameters in the function of time, as well as possibilities to predict the properties of nitrided layers. For in situ visualization of the growth of the nitrided layer, computer procedures were developed which make use of the results of the correlations of direct and differential voltage and time runs of the process result sensor (magnetic sensor), with the proper layer growth stage. Computer procedures make it possible to combine, in the duration of the process, the registered voltage and time runs with the models of the process. PMID:22315536

  12. Visual control in children with developmental dyslexia Controle visual em crianças com dislexia do desenvolvimento

    OpenAIRE

    Stella Maris Costa Castro; Cintia Alves Salgado; Fernando Portolani Andrade; Sylvia Maria Ciasca; Keila Miriam Monteiro de Carvalho

    2008-01-01

    PURPOSE: To assess binocular control in children with dyslexia. METHODS: Cross-sectional study with 26 children who were submitted to a set of ophthalmologic and visual tests. RESULTS: In the dyslexic children less eye movement control in voluntary convergence and unstable binocular fixation was observed. CONCLUSION: The results support the hypothesis that developmental dyslexia might present deficits which involve the magnocellular pathway and a part of the posterior cortical attentional net...

  13. Robust Visual Control of Parallel Robots under Uncertain Camera Orientation

    Directory of Open Access Journals (Sweden)

    Miguel A. Trujano

    2012-10-01

    Full Text Available This work presents a stability analysis and experimental assessment of a visual control algorithm applied to a redundant planar parallel robot under uncertainty in relation to camera orientation. The key feature of the analysis is a strict Lyapunov function that allows the conclusion of asymptotic stability without invoking the Barbashin‐Krassovsky‐LaSalle invariance theorem. The controller does not rely on velocity measurements and has a structure similar to a classic Proportional Derivative control algorithm. Experiments in a laboratory prototype show that uncertainty in camera orientation does not significantly degrade closed‐loop performance.

  14. Robust Control for High-Speed Visual Servoing Applications

    DEFF Research Database (Denmark)

    Ellekilde, Lars-Peter; Favrholdt, Peter; Paulin, Mads; Petersen, Henrik Gordon

    2007-01-01

    This paper presents a new control scheme for visual servoing applications. The approach employs quadratic optimization, and explicitly handles both joint position, velocity and acceleration limits. Contrary to existing techniques, our method does not rely on large safety margins and slow task...... execution to avoid joint limits, and is hence able to exploit the full potential of the robot. Furthermore, our control scheme guarantees a well-defined behavior of the robot even when it is in a singular configuration, and thus handles both internal and external singularities robustly. We demonstrate the...... correctness and efficiency of our approach in a number of visual servoing applications, and compare it to a range of previously proposed techniques....

  15. Ultrasonic and visual control systems for SUPERPHENIX steam generator controls

    International Nuclear Information System (INIS)

    FRAMATOME and ANSALDO have been requested, by EDF, to develop and fabricate a new tool to perform the SUPERPHENIX (SPX) Steam Generators (SG) Ultrasonic (US) and Visual (VI) inspections. Following a convincing demonstration of suitability (1993) and a final acceptance by EDF (1996), an inspection campaign has been carried out (1997/1998), for several SG tubes. US and VI inspection of SPX SG tubes is a complex operation, on one hand for the very severe technical specifications imposed, concerning the flaw detection/sizing and the high inspection speed and, on the other hand, by unfavorable characteristics of tubes to be inspected, as regards of problems of introduction/movement into the tubes of the inspection devices (probe and electrical extension), in particular: the very important length (∼ 100 m), the tortuous geometry (helical tubes with some orthogonal bends) and significant friction of inspection devices on the tube surface (due to presence of an oxide film and corrosion products). The FRAMATOME/ANSALDO's inspection system includes: - some innovative US and VI probes, provided of a sophisticated Signal Acquisition System (developed by FRAMATOME); - a Cleaning and Gauging System of internal surfaces of the SG tubes (developed by ANSALDO); - Hydraulic Driving System, to move the inspection probes inside the tube (developed by ANSALDO). This paper presents the FRAMATOME/ANSALDO's inspection system and the synthesis of the inspection campaign of SPX SG tubes carried out in 1997/1998. (authors)

  16. Visual Estimation and Control of Robot Manipulating Systems

    OpenAIRE

    Robuffo Giordano, Paolo

    2008-01-01

    With this sentence from his Metaphysica, Aristotle perfectly introduces us to the importance of eyesight for humans, as well as for any advanced living being. Since, to a large extent, robotics is concerned with the emulation of human skills in an artificial context, a natural requirement is to cope with vision for a full interaction with the world. In this respect, this Thesis explores the problem of exploiting visual information to control the motion of robotic systems equipp...

  17. The effect of a visual indicator on rate of visual search Evidence for processing control

    Science.gov (United States)

    Holmgren, J. E.

    1974-01-01

    Search rates were estimated from response latencies in a visual search task of the type used by Atkinson et al. (1969), in which a subject searches a small set of letters to determine the presence or absence of a predesignated target. Half of the visual displays contained a marker above one of the letters. The marked letter was the only one that had to be checked to determine whether or not the display contained the target. The presence of a marker in a display significantly increased the estimated rate of search, but the data clearly indicated that subjects did not restrict processing to the marked item. Letters in the vicinity of the marker were also processed. These results were interpreted as showing that subjects are able to exercise some degree of control over the search process in this type of task.

  18. Phase sensitivity of complex cells in primary visual cortex.

    Science.gov (United States)

    Hietanen, M A; Cloherty, S L; van Kleef, J P; Wang, C; Dreher, B; Ibbotson, M R

    2013-05-01

    Neurons in the primary visual cortex are often classified as either simple or complex based on the linearity (or otherwise) of their response to spatial luminance contrast. In practice, classification is typically based on Fourier analysis of a cell's response to an optimal drifting sine-wave grating. Simple cells are generally considered to be linear and produce responses modulated at the fundamental frequency of the stimulus grating. In contrast, complex cells exhibit significant nonlinearities that reduce the response at the fundamental frequency. Cells can therefore be easily and objectively classified based on the relative modulation of their responses - the ratio of the phase-sensitive response at the fundamental frequency of the stimulus (F₁) to the phase-invariant sustained response (F₀). Cells are classified as simple if F₁/F₀>1 and complex if F₁/F₀<1. This classification is broadly consistent with criteria based on the spatial organisation of cells' receptive fields and is accordingly presumed to reflect disparate functional roles of simple and complex cells in coding visual information. However, Fourier analysis of spiking responses is sensitive to the number of spikes available - F₁/F₀ increases as the number of spikes is reduced, even for phase-invariant complex cells. Moreover, many complex cells encountered in the laboratory exhibit some phase sensitivity, evident as modulation of their responses at the fundamental frequency. There currently exists no objective quantitative means of assessing the significance or otherwise of these modulations. Here we derive a statistical basis for objectively assessing whether the modulation of neuronal responses is reliable, thereby adding a level of statistical certainty to measures of phase sensitivity. We apply our statistical analysis to neuronal responses to moving sine-wave gratings recorded from 367 cells in cat primary visual cortex. We find that approximately 60% of complex cells exhibit

  19. Glial cell development and function in the Drosophila visual system

    OpenAIRE

    CHOTARD, CAROLE; Salecker, Iris

    2007-01-01

    In the developing nervous system, building a functional neuronal network relies on coordinating the formation, specification and survival to diverse neuronal and glial cell subtypes. The establishment of neuronal connections further depends on sequential neuron–neuron and neuron–glia interactions that regulate cell-migration patterns and axon guidance. The visual system of Drosophila has a highly regular, retinotopic organization into reiterated interconnected synaptic circuits. It is therefo...

  20. Real-time visual servoing using controlled illumination

    International Nuclear Information System (INIS)

    A real-time visual servoing approach is applied to robotic tasks consisting of the positioning of the end effector with respect to a priori known polyhedral objects. The vision apparatus is constituted by a compact CCD camera rigidly coupled with two laser stripes mounted on the wrist of a robot manipulator. The objective is to servo the robot end effector at a constant position and orientation with respect to a known object in three-dimensional space in the field of view of the sensory system. The approach is expressed in terms of sensor-based control (Samson et al. 1991) applied to visual servoing (Chaumette 1990; Urban 1990). In the case of camera-light stripe coupling, the elementary visual signals used for visual servoing are the points of discontinuity in the light stripes. The feasibility of the approach is demonstrated in a factory automation task consisting of the positioning of the end-effector tool over a vehicle battery. Both simulation and experimentation results are presented, proving the robustness and stability of the algorithm. 19 refs

  1. Visualization and targeted disruption of protein interactions in living cells

    OpenAIRE

    Herce, Henry D.; Deng, Wen; Helma, Jonas; Leonhardt, Heinrich; Cardoso, M. Cristina

    2013-01-01

    Protein–protein interactions are the basis of all processes in living cells, but most studies of these interactions rely on biochemical in vitro assays. Here we present a simple and versatile fluorescent-three-hybrid (F3H) strategy to visualize and target protein–protein interactions. A high-affinity nanobody anchors a GFP-fusion protein of interest at a defined cellular structure and the enrichment of red-labelled interacting proteins is measured at these sites. With this approach, we visual...

  2. Developmental changes in cytosolic coupling between epidermis cells as visualized by photoactivation of fluorescein

    DEFF Research Database (Denmark)

    Liu, Xiangdong; Martens, Helle; Schulz, Alexander

    Developmental changes in cytosolic coupling between epidermis cells as visualized by photoactivation of fluorescein.......Developmental changes in cytosolic coupling between epidermis cells as visualized by photoactivation of fluorescein....

  3. Simple Instrumental and Visual Tests for Nonlaboratory Environmental Control

    Science.gov (United States)

    Eksperiandova, L. P.; Khimchenko, S. V.; Stepanenko, N. A.; Shcherbakov, I. B.

    2016-01-01

    Proposed are simple and available techniques that can be used for rapid and reliable environmental control specifically of natural water by means of instrumental and visual tests in outdoor conditions. Developed are the chemical colorimetric modes for fast detection of socially dangerous trace impurities in water such as Co(II), Pd(II), and Rh(III) as well as NO2−-ions and Fe(III) serving as model impurities. Application of portable digital devices and scanner allows estimating the color coordinates and increasing the accuracy and sensitivity of the tests. The combination of complex formation with preconcentration of colored complexes replaces the sensitive but time-consuming and capricious kinetic method that is usually used for this purpose at the more convenient and reliable colorimetric method. As the test tools, the following ones are worked out: polyurethane foam tablets with sorbed colored complexes, the two-layer paper sandwich packaged in slide adapter and saturated by reagents, and polyethylene terephthalate blister with dried reagents. Fast analysis of polyurethane foam tablets is realized using a pocket digital RGB-colorimeter or portable photometer. Express analysis of two-layer paper sandwich or polyethylene terephthalate blister is realized by visual and instrumental tests. The metrological characteristics of the developed visual and instrumental express analysis techniques are estimated. PMID:27247827

  4. Simple Instrumental and Visual Tests for Nonlaboratory Environmental Control

    Directory of Open Access Journals (Sweden)

    L. P. Eksperiandova

    2016-01-01

    Full Text Available Proposed are simple and available techniques that can be used for rapid and reliable environmental control specifically of natural water by means of instrumental and visual tests in outdoor conditions. Developed are the chemical colorimetric modes for fast detection of socially dangerous trace impurities in water such as Co(II, Pd(II, and Rh(III as well as NO2--ions and Fe(III serving as model impurities. Application of portable digital devices and scanner allows estimating the color coordinates and increasing the accuracy and sensitivity of the tests. The combination of complex formation with preconcentration of colored complexes replaces the sensitive but time-consuming and capricious kinetic method that is usually used for this purpose at the more convenient and reliable colorimetric method. As the test tools, the following ones are worked out: polyurethane foam tablets with sorbed colored complexes, the two-layer paper sandwich packaged in slide adapter and saturated by reagents, and polyethylene terephthalate blister with dried reagents. Fast analysis of polyurethane foam tablets is realized using a pocket digital RGB-colorimeter or portable photometer. Express analysis of two-layer paper sandwich or polyethylene terephthalate blister is realized by visual and instrumental tests. The metrological characteristics of the developed visual and instrumental express analysis techniques are estimated.

  5. Cognitive Control Network Contributions to Memory-Guided Visual Attention.

    Science.gov (United States)

    Rosen, Maya L; Stern, Chantal E; Michalka, Samantha W; Devaney, Kathryn J; Somers, David C

    2016-05-01

    Visual attentional capacity is severely limited, but humans excel in familiar visual contexts, in part because long-term memories guide efficient deployment of attention. To investigate the neural substrates that support memory-guided visual attention, we performed a set of functional MRI experiments that contrast long-term, memory-guided visuospatial attention with stimulus-guided visuospatial attention in a change detection task. Whereas thedorsal attention networkwas activated for both forms of attention, thecognitive control network(CCN) was preferentially activated during memory-guided attention. Three posterior nodes in the CCN, posterior precuneus, posterior callosal sulcus/mid-cingulate, and lateral intraparietal sulcus exhibited the greatest specificity for memory-guided attention. These 3 regions exhibit functional connectivity at rest, and we propose that they form a subnetwork within the broader CCN. Based on the task activation patterns, we conclude that the nodes of this subnetwork are preferentially recruited for long-term memory guidance of visuospatial attention. PMID:25750253

  6. A Multimedia Visual Feedback in the Web-controlled Laboratory

    Directory of Open Access Journals (Sweden)

    J. Turan

    2012-06-01

    Full Text Available The paper presents development work related to create WWW based remote control laboratory for teaching Applied Photonics. In order to minimize the cost at the end-user domain, simple WWW browser with fundamental plug-in (Java applets, HTML Pages and LabWindows applets to support the remote control and video transmission functionality of the remote control is proposed. As for telepresence and monitoring of device actions, a simple type zooming web-camera is connected to the hosting multimedia PC via the USB port. The web-camera assists in visual feedback of the system and presents the feeling of telepresence for the end-user (student. USB web-cameras are normally efficient and the presence of another video server is not necessary in this case, thanks to LabWindows.

  7. Ankylosing Spondylitis and Posture Control: The Role of Visual Input

    Directory of Open Access Journals (Sweden)

    Alessandro Marco De Nunzio

    2015-01-01

    Full Text Available Objectives. To assess the motor control during quiet stance in patients with established ankylosing spondylitis (AS and to evaluate the effect of visual input on the maintenance of a quiet posture. Methods. 12 male AS patients (mean age 50.1 ± 13.2 years and 12 matched healthy subjects performed 2 sessions of 3 trials in quiet stance, with eyes open (EO and with eyes closed (EC on a baropodometric platform. The oscillation of the centre of feet pressure (CoP was acquired. Indices of stability and balance control were assessed by the sway path (SP of the CoP, the frequency bandwidth (FB1 that includes the 80% of the area under the amplitude spectrum, the mean amplitude of the peaks (MP of the sway density curve (SDC, and the mean distance (MD between 2 peaks of the SDC. Results. In severe AS patients, the MD between two peaks of the SDC and the SP of the center of feet pressure were significantly higher than controls during both EO and EC conditions. The MP was significantly reduced just on EC. Conclusions. Ankylosing spondylitis exerts negative effect on postural stability, not compensable by visual inputs. Our findings may be useful in the rehabilitative management of the increased risk of falling in AS.

  8. Losing the big picture: how religion may control visual attention.

    Directory of Open Access Journals (Sweden)

    Lorenza S Colzato

    Full Text Available Despite the abundance of evidence that human perception is penetrated by beliefs and expectations, scientific research so far has entirely neglected the possible impact of religious background on attention. Here we show that Dutch Calvinists and atheists, brought up in the same country and culture and controlled for race, intelligence, sex, and age, differ with respect to the way they attend to and process the global and local features of complex visual stimuli: Calvinists attend less to global aspects of perceived events, which fits with the idea that people's attentional processing style reflects possible biases rewarded by their religious belief system.

  9. Visual control in children with developmental dyslexia Controle visual em crianças com dislexia do desenvolvimento

    Directory of Open Access Journals (Sweden)

    Stella Maris Costa Castro

    2008-12-01

    Full Text Available PURPOSE: To assess binocular control in children with dyslexia. METHODS: Cross-sectional study with 26 children who were submitted to a set of ophthalmologic and visual tests. RESULTS: In the dyslexic children less eye movement control in voluntary convergence and unstable binocular fixation was observed. CONCLUSION: The results support the hypothesis that developmental dyslexia might present deficits which involve the magnocellular pathway and a part of the posterior cortical attentional network.OBJETIVO: Avaliar o controle binocular em crianças com dislexia. MÉTODOS: Estudo transversal do qual participaram 26 crianças, nas quais foram aplicadas uma série de exames oftalmológicos e visuais. RESULTADOS: Nas crianças com dislexia observou-se controle menor na convergência voluntária e na estabilidade da fixação binocular. CONCLUSÃO: Os resultados apóiam a hipótese de que na dislexia do desenvolvimento podem ocorrer déficits que envolvem a via visual magnocelular e uma parte da rede cortical posterior da atenção.

  10. Effect of Contrast on Visual Spatial Summation in Different Cell Categories in Cat Primary Visual Cortex.

    Directory of Open Access Journals (Sweden)

    Ke Chen

    Full Text Available Multiple cell classes have been found in the primary visual cortex, but the relationship between cell types and spatial summation has seldom been studied. Parvalbumin-expressing inhibitory interneurons can be distinguished from pyramidal neurons based on their briefer action potential durations. In this study, we classified V1 cells into fast-spiking units (FSUs and regular-spiking units (RSUs and then examined spatial summation at high and low contrast. Our results revealed that the excitatory classical receptive field and the suppressive non-classical receptive field expanded at low contrast for both FSUs and RSUs, but the expansion was more marked for the RSUs than for the FSUs. For most V1 neurons, surround suppression varied as the contrast changed from high to low. However, FSUs exhibited no significant difference in the strength of suppression between high and low contrast, although the overall suppression decreased significantly at low contrast for the RSUs. Our results suggest that the modulation of spatial summation by stimulus contrast differs across populations of neurons in the cat primary visual cortex.

  11. Closed-loop response properties of a visual interneuron involved in fly optomotor control.

    Science.gov (United States)

    Ejaz, Naveed; Krapp, Holger G; Tanaka, Reiko J

    2013-01-01

    Due to methodological limitations neural function is mostly studied under open-loop conditions. Normally, however, nervous systems operate in closed-loop where sensory input is processed to generate behavioral outputs, which again change the sensory input. Here, we investigate the closed-loop responses of an identified visual interneuron, the blowfly H1-cell, that is part of a neural circuit involved in optomotor flight and gaze control. Those behaviors may be triggered by attitude changes during flight in turbulent air. The fly analyses the resulting retinal image shifts and performs compensatory body and head rotations to regain its default attitude. We developed a fly robot interface to study H1-cell responses in a 1 degree-of-freedom image stabilization task. Image shifts, induced by externally forced rotations, modulate the cell's spike rate that controls counter rotations of a mobile robot to minimize relative motion between the robot and its visual surroundings. A feedback controller closed the loop between neural activity and the rotation of the robot. Under these conditions we found the following H1-cell response properties: (i) the peak spike rate decreases when the mean image velocity is increased, (ii) the relationship between spike rate and image velocity depends on the standard deviation of the image velocities suggesting adaptive scaling of the cell's signaling range, and (iii) the cell's gain decreases linearly with increasing image accelerations. Our results reveal a remarkable qualitative similarity between the response dynamics of the H1-cell under closed-loop conditions with those obtained in previous open-loop experiments. Finally, we show that the adaptive scaling of the H1-cell's responses, while maximizing information on image velocity, decreases the cell's sensitivity to image accelerations. Understanding such trade-offs in biological vision systems may advance the design of smart vision sensors for autonomous robots. PMID:23543872

  12. Remote control of ATLAS-MPX Network and Data Visualization

    International Nuclear Information System (INIS)

    The ATLAS-MPX Network is a network of 15 Medipix2-based detector devices, installed in various positions in the ATLAS detector at CERN, Geneva. The aim of the network is to perform a real-time measurement of the spectral characteristics and the composition of radiation inside the ATLAS detector during its operation. The remote control system of ATLAS-MPX controls and configures all the devices from one place, via a web interface, accessible from different operating systems. The Data Visualization application, also with a web interface, has been developed in order to present measured data to the scientific community. It allows to browse through recorded frames from all devices and to search for specific frames by date and time. Charts containing the number of different types of tracks in each frame as a function of time may be rendered from the database.

  13. Visualization and targeted disruption of protein interactions in living cells.

    Science.gov (United States)

    Herce, Henry D; Deng, Wen; Helma, Jonas; Leonhardt, Heinrich; Cardoso, M Cristina

    2013-01-01

    Protein-protein interactions are the basis of all processes in living cells, but most studies of these interactions rely on biochemical in vitro assays. Here we present a simple and versatile fluorescent-three-hybrid (F3H) strategy to visualize and target protein-protein interactions. A high-affinity nanobody anchors a GFP-fusion protein of interest at a defined cellular structure and the enrichment of red-labelled interacting proteins is measured at these sites. With this approach, we visualize the p53-HDM2 interaction in living cells and directly monitor the disruption of this interaction by Nutlin 3, a drug developed to boost p53 activity in cancer therapy. We further use this approach to develop a cell-permeable vector that releases a highly specific peptide disrupting the p53 and HDM2 interaction. The availability of multiple anchor sites and the simple optical readout of this nanobody-based capture assay enable systematic and versatile analyses of protein-protein interactions in practically any cell type and species. PMID:24154492

  14. Visualization of Carbon Nanoparticles Within Cells and Implications for Toxicity

    Science.gov (United States)

    Porter, Alexandra; Gass, Mhairi

    Carbon nanostructures (CNS), such as C60, single-walled nanotubes (SWNTs) exhibit extraordinary properties and are one of the most commercially relevant class of NS. CNS have already found uses in high-performance sports equipment (nanotubes) and face cream (C60), whilst potential applications include optical and electronic materials and superconductors. Following the huge growth in these nanotechnology-related industries, significant concerns have arisen about their potential toxicity and impact on the environment. A lack in understanding of the interaction of such small structures with cellular material has resulted in concerns over their impact on human health. The potential toxicity of CNS and safety to human health requires an understanding of their interaction with cells and this in turn relies on the measurement of the pathways by which they enter the cell, their spatial distribution within and whether the CNS are transformed by the action of the cell; visualization of intracellular CNS is therefore imperative. However visualizing unlabelled CNS within cells is demanding because it is difficult to distinguish CNS from carbon-rich organelles given their similarity in composition and dimensions. In particular, the challenge lies in translating analytical imaging tools developed for inorganic systems to organic systems. This chapter describes how the state-of-the-art transmission electron microscopy (TEM) techniques, such as low-loss energy-filtered TEM (EFTEM) can be employed to differentiate between unlabelled C60, SWNTs and the cell. Further, we demonstrate how these techniques can be used to trace the uptake of CNS into the cell and to assess their localized effects on cell structure.

  15. Therapeutic Options for Controlling Fluids in the Visual System

    Science.gov (United States)

    Curry, Kristina M.; Wotring, Virginia E.

    2014-01-01

    Visual Impairment/Intracranial Pressure (VIIP) is a newly recognized risk at NASA. The VIIP project examines the effect of long-term exposure to microgravity on vision of crewmembers before and after they return to Earth. Diamox (acetazolamide) is a medication which is used to decrease intraocular pressure; however, it carries a 3% risk of kidney stones. Astronauts are at a higher risk of kidney stones during spaceflight and the use Diamox would only increase the risk; therefore alternative therapies were investigated. Histamine 2 (H2) antagonist acid blockers such as cimetidine, ranitidine, famotidine and nizatidine are typically used to relieve the symptoms of gastroesophageal reflux disease (GERD). H2 receptors have been found in the human visual system, which has led to research on the use of H2 antagonist blockers to control fluid production in the human eye. Another potential therapeutic strategy is targeted at aquaporins, which are water channels that help maintain fluid homeostasis. Aquaporin antagonists are also known to affect intracranial pressure which can in turn alter intraocular pressure. Studies on aquaporin antagonists suggest high potential for effective treatment. The primary objective of this investigation is to review existing research on alternate medications or therapy to significantly reduce intracranial and intraocular pressure. A literature review was conducted. Even though we do not have all the answers quite yet, a considerable amount of information was discovered, and findings were narrowed, which should allow for more conclusive answers to be found in the near future.

  16. Visual-Motion Cueing in Altitude and Yaw Control

    Science.gov (United States)

    Johnson, Walter W.; Schroeder, Jeffery; Statler, Irving C. (Technical Monitor)

    1994-01-01

    Research conducted using the Vertical Motion Simulator at the NASA Ames Research Center examined the contributions of platform motion and visual level-of-detail (LOD) cueing to tasks that required altitude and/or yaw control in a simulated AH-64 Apache helicopter. Within the altitude control tasks the LOD manipulation caused optical density to change across altitudes by a small, moderate, or large amount; while platform motion was either present or absent. The results from these tasks showed that both constant optical density and platform motion improved altitude awareness in an altitude repositioning task, while the presence of platform motion also led to improved performance in a vertical rate control task. The yaw control tasks had pilots'sit 4.5 ft in front of the center of rotation, thus subjecting them to both rotational and lateral motions during a yaw. The pilots were required to regulate their yaw, while the platform motion was manipulated in order to present all combinations of the resulting rotational and lateral motion components. Ratings of simulation fidelity and sensed platform motion showed that the pilots were relatively insensitive to the rotational component, but highly aware of the lateral component. Together these findings show that: 1) platform motion cues are important when speed regulation is required during altitude change; 2) platform motion contributes to the perception of movement amplitude; 3) lateral, but not rotational, motion cues are essential to the perception of vehicle yaw; and 4) LOD management yielding constant optical density across altitudes improves altitude awareness.

  17. Age-related changes in the attentional control of visual cortex: A selective problem in the left visual hemifield

    OpenAIRE

    Nagamatsu, Lindsay S.; Carolan, Patrick; Liu-Ambrose, Teresa Y L; Handy, Todd C

    2011-01-01

    To what extent does our visual-spatial attention change with age? In this regard, it has been previously reported that relative to young controls, seniors show delays in attention-related sensory facilitation. Given this finding, our study was designed to examine two key questions regarding age-related changes in the effect of spatial attention on sensory-evoked responses in visual cortex –– are there visual field differences in the age-related impairments in sensory processing, and do these ...

  18. Direct Visualization of De novo Lipogenesis in Single Living Cells

    Science.gov (United States)

    Li, Junjie; Cheng, Ji-Xin

    2014-10-01

    Increased de novo lipogenesis is being increasingly recognized as a hallmark of cancer. Despite recent advances in fluorescence microscopy, autoradiography and mass spectrometry, direct observation of de novo lipogenesis in living systems remains to be challenging. Here, by coupling stimulated Raman scattering (SRS) microscopy with isotope labeled glucose, we were able to trace the dynamic metabolism of glucose in single living cells with high spatial-temporal resolution. As the first direct visualization, we observed that glucose was largely utilized for lipid synthesis in pancreatic cancer cells, which occurs at a much lower rate in immortalized normal pancreatic epithelial cells. By inhibition of glycolysis and fatty acid synthase (FAS), the key enzyme for fatty acid synthesis, we confirmed the deuterium labeled lipids in cancer cells were from de novo lipid synthesis. Interestingly, we also found that prostate cancer cells exhibit relatively lower level of de novo lipogenesis, but higher fatty acid uptake compared to pancreatic cancer cells. Together, our results demonstrate a valuable tool to study dynamic lipid metabolism in cancer and other disorders.

  19. Super-resolution imaging with Pontamine Fast Scarlet 4BS enables direct visualization of cellulose orientation and cell connection architecture in onion epidermis cells

    OpenAIRE

    Liesche, Johannes; Ziomkiewicz, Iwona; Schulz, Alexander

    2013-01-01

    BackgroundIn plants, a complex cell wall protects cells and defines their shape. Cellulose fibrils form a multilayered network inside the cell-wall matrix that plays a direct role in controlling cell expansion. Resolving the structure of this network will allow us to comprehend the relationship of cellulose fibril orientation and growth.The fluorescent dye Pontamine Fast Scarlet 4BS (PFS) was shown to stain cellulose with high specificity and could be used to visualize cellulose bundles in ce...

  20. Development of visual 3D virtual environment for control software

    Science.gov (United States)

    Hirose, Michitaka; Myoi, Takeshi; Amari, Haruo; Inamura, Kohei; Stark, Lawrence

    1991-01-01

    Virtual environments for software visualization may enable complex programs to be created and maintained. A typical application might be for control of regional electric power systems. As these encompass broader computer networks than ever, construction of such systems becomes very difficult. Conventional text-oriented environments are useful in programming individual processors. However, they are obviously insufficient to program a large and complicated system, that includes large numbers of computers connected to each other; such programming is called 'programming in the large.' As a solution for this problem, the authors are developing a graphic programming environment wherein one can visualize complicated software in virtual 3D world. One of the major features of the environment is the 3D representation of concurrent process. 3D representation is used to supply both network-wide interprocess programming capability (capability for 'programming in the large') and real-time programming capability. The authors' idea is to fuse both the block diagram (which is useful to check relationship among large number of processes or processors) and the time chart (which is useful to check precise timing for synchronization) into a single 3D space. The 3D representation gives us a capability for direct and intuitive planning or understanding of complicated relationship among many concurrent processes. To realize the 3D representation, a technology to enable easy handling of virtual 3D object is a definite necessity. Using a stereo display system and a gesture input device (VPL DataGlove), our prototype of the virtual workstation has been implemented. The workstation can supply the 'sensation' of the virtual 3D space to a programmer. Software for the 3D programming environment is implemented on the workstation. According to preliminary assessments, a 50 percent reduction of programming effort is achieved by using the virtual 3D environment. The authors expect that the 3D

  1. A controlled study of vigabatrin and visual abnormalities

    OpenAIRE

    Manuchehri, K.; Goodman, S; Siviter, L.; Nightingale, S.

    2000-01-01

    AIMS—To assess the visual function in epileptic patients who have received vigabatrin; to compare this with the visual function in similar epileptic patients who have never received vigabatrin; to investigate whether the severity of visual field defect (VFD) is related to the dose of vigabatrin; to consider other factors that may correlate with the severity of VFD.
METHODS—21 consecutive patients who had taken vigabatrin at some time in their lives were enrolled from the epilepsy clinic of th...

  2. Case studies on design, simulation and visualization of control and measurement applications using REX control system

    Science.gov (United States)

    Ozana, Stepan; Pies, Martin; Docekal, Tomas

    2016-06-01

    REX Control System is a professional advanced tool for design and implementation of complex control systems that belongs to softPLC category. It covers the entire process starting from simulation of functionality of the application before deployment, through implementation on real-time target, towards analysis, diagnostics and visualization. Basically it consists of two parts: the development tools and the runtime system. It is also compatible with Simulink environment, and the way of implementation of control algorithm is very similar. The control scheme is finally compiled (using RexDraw utility) and uploaded into a chosen real-time target (using RexView utility). There is a wide variety of hardware platforms and real-time operating systems supported by REX Control System such as for example Windows Embedded, Linux, Linux/Xenomai deployed on SBC, IPC, PAC, Raspberry Pi and others with many I/O interfaces. It is modern system designed both for measurement and control applications, offering a lot of additional functions concerning data archiving, visualization based on HTML5, and communication standards. The paper will sum up possibilities of its use in educational process, focused on control of case studies of physical models with classical and advanced control algorithms.

  3. Development of an autonomous biological cell manipulator with single-cell electroporation and visual servoing capabilities.

    Science.gov (United States)

    Sakaki, Kelly; Dechev, Nikolai; Burke, Robert D; Park, Edward J

    2009-08-01

    Studies of single cells via microscopy and microinjection are a key component in research on gene functions, cancer, stem cells, and reproductive technology. As biomedical experiments become more complex, there is an urgent need to use robotic systems to improve cell manipulation and microinjection processes. Automation of these tasks using machine vision and visual servoing creates significant benefits for biomedical laboratories, including repeatability of experiments, higher throughput, and improved cell viability. This paper presents the development of a new 5-DOF robotic manipulator, designed for manipulating and microinjecting single cells. This biological cell manipulator (BCM) is capable of autonomous scanning of a cell culture followed by autonomous injection of cells using single-cell electroporation (SCE). SCE does not require piercing the cell membrane, thereby keeping the cell membrane fully intact. The BCM features high-precision 3-DOF translational and 2-DOF rotational motion, and a second z-axis allowing top-down placement of a micropipette tip onto the cell membrane for SCE. As a technical demonstration, the autonomous visual servoing and microinjection capabilities of the single-cell manipulator are experimentally shown using sea urchin eggs. PMID:19605307

  4. Visual reliance for balance control in older adults persists when visual information is disrupted by artificial feedback delays.

    Directory of Open Access Journals (Sweden)

    Ting Ting Yeh

    Full Text Available Sensory information from our eyes, skin and muscles helps guide and correct balance. Less appreciated, however, is that delays in the transmission of sensory information between our eyes, limbs and central nervous system can exceed several 10s of milliseconds. Investigating how these time-delayed sensory signals influence balance control is central to understanding the postural system. Here, we investigate how delayed visual feedback and cognitive performance influence postural control in healthy young and older adults. The task required that participants position their center of pressure (COP in a fixed target as accurately as possible without visual feedback about their COP location (eyes-open balance, or with artificial time delays imposed on visual COP feedback. On selected trials, the participants also performed a silent arithmetic task (cognitive dual task. We separated COP time series into distinct frequency components using low and high-pass filtering routines. Visual feedback delays affected low frequency postural corrections in young and older adults, with larger increases in postural sway noted for the group of older adults. In comparison, cognitive performance reduced the variability of rapid center of pressure displacements in young adults, but did not alter postural sway in the group of older adults. Our results demonstrate that older adults prioritize vision to control posture. This visual reliance persists even when feedback about the task is delayed by several hundreds of milliseconds.

  5. Visualizing dopamine released from living cells using a nanoplasmonic probe

    Science.gov (United States)

    Qin, W. W.; Wang, S. P.; Li, J.; Peng, T. H.; Xu, Y.; Wang, K.; Shi, J. Y.; Fan, C. H.; Li, D.

    2015-09-01

    We report the development of an ultrasensitive nanoplasmonic probe for discriminative detection and imaging of dopamine released from living cells. The sensing mechanism is based on the dopamine-induced seeded-growth of Au nanoparticles (Au NPs) that leads to the shift of the plasmon band. This platform allows for the detection of dopamine with a detection limit down to 0.25 pM within 1 min. This nanoplasmonic assay is further applied to visualize the release of dopamine from living rat pheochromocytoma (PC12) cells under ATP-stimulation with dark-field microscopy (DFM). The DFM results together with real time fluorescence imaging of PC12 cells stained with the Fluo calcium indicator, suggested that ATP stimulated-release of dopamine is concomitant with the Ca2+ influx, and the influx of Ca2+ is through ATP-activated channels instead of the voltage-gated Ca2+ channel (VGC).We report the development of an ultrasensitive nanoplasmonic probe for discriminative detection and imaging of dopamine released from living cells. The sensing mechanism is based on the dopamine-induced seeded-growth of Au nanoparticles (Au NPs) that leads to the shift of the plasmon band. This platform allows for the detection of dopamine with a detection limit down to 0.25 pM within 1 min. This nanoplasmonic assay is further applied to visualize the release of dopamine from living rat pheochromocytoma (PC12) cells under ATP-stimulation with dark-field microscopy (DFM). The DFM results together with real time fluorescence imaging of PC12 cells stained with the Fluo calcium indicator, suggested that ATP stimulated-release of dopamine is concomitant with the Ca2+ influx, and the influx of Ca2+ is through ATP-activated channels instead of the voltage-gated Ca2+ channel (VGC). Electronic supplementary information (ESI) available: Fig. S1-S4 and Table S1. See DOI: 10.1039/c5nr04433b

  6. Survey of Visual and Force/Tactile Control of Robots for Physical Interaction in Spain

    OpenAIRE

    Fernando Torres; Jorge Pomares; Garcia, Gabriel J.; Corrales, Juan A.

    2009-01-01

    Sensors provide robotic systems with the information required to perceive the changes that happen in unstructured environments and modify their actions accordingly. The robotic controllers which process and analyze this sensory information are usually based on three types of sensors (visual, force/torque and tactile) which identify the most widespread robotic control strategies: visual servoing control, force control and tactile control. This paper presents a detailed review on the sensor arc...

  7. Closed-loop response properties of a visual interneuron involved in fly optomotor control

    Directory of Open Access Journals (Sweden)

    Naveed eEjaz

    2013-03-01

    Full Text Available Due to methodological limitations neural function is mostly studied under open-loop conditions. Normally, however, nervous systems operate in closed-loop where sensory input is processed to generate behavioural outputs, which again change the sensory input. Here, we investigate the closed-loop responses of an identified visual interneuron, the blowfly H1-cell, that is part of a neural circuit involved in optomotor flight and gaze control. Those behaviours may be triggered by attitude changes during flight in turbulent air. The fly analyses the resulting retinal image shifts and performs compensatory body and head rotations to regain its default attitude. We developed a fly-robot interface to study H1-cell responses in a 1 degree-of-freedom image stabilization task. Image shifts, induced by externally forced rotations, modulate the cell’s spike rate that controls counter rotations of a mobile robot to minimize relative motion between the robot and its visual surroundings. A feedback controller closed the loop between neural activity and the rotation of the robot. Under these conditions we found the following H1-cell response properties: (i the peak spike rate decreases when the mean image velocity is increased, (ii the relationship between spike rate and image velocity depends on the standard deviation of the image velocities suggesting adaptive scaling of the cell’s signalling range, and (iii the cell’s gain decreases linearly with increasing image accelerations.Our results reveal a remarkable qualitative similarity between the response dynamics of the H1-cell under closed-loop conditions with those obtained in previous open-loop experiments. Finally, we show that the adaptive scaling of the H1-cell’s responses, while maximizing information on image velocity, decreases the cell’s sensitivity to image accelerations. Understanding such trade-offs in biological vision systems may advance the design of smart vision sensors for autonomous

  8. A design pattern language to assist the design of alarm visualizations for operating control systems

    OpenAIRE

    Romero Gómez, Rosa María

    2015-01-01

    Mención Internacional en el título de doctor With the growing emphasis on visualization as a mechanism for analysing and exploring large and complex data sets, visualization research has recognized the need of reusing prior design knowledge instead of starting from scratch. This fact is especially relevant in designing control systems in which alarm visualizations are key artefacts for human operators to maintain an awareness of the state of the process under control. In this context, desi...

  9. A Robot-Assisted Cell Manipulation System with an Adaptive Visual Servoing Method

    OpenAIRE

    Yu Xie; Feng Zeng; Wenming Xi; Yunlei Zhou; Houde Liu; Mingliang Chen

    2016-01-01

    Robot-assisted cell manipulation is gaining attention for its ability in providing high throughput and high precision cell manipulation for the biological industry. This paper presents a visual servo microrobotic system for cell microinjection. We investigated the automatic cell autofocus method that reduced the complexity of the system. Then, we produced an adaptive visual processing algorithm to detect the location of the cell and micropipette toward the uneven illumination problem. Fourtee...

  10. Guideline implementation in clinical practice: Use of statistical process control charts as visual feedback devices

    Directory of Open Access Journals (Sweden)

    Fahad A Al-Hussein

    2009-01-01

    Conclusions: A process of audits in the context of statistical process control is necessary for any improvement in the implementation of guidelines in primary care. Statistical process control charts are an effective means of visual feedback to the care providers.

  11. Industrial image processing visual quality control in manufacturing

    CERN Document Server

    Demant, Christian; Garnica, Carsten

    2013-01-01

    This practical introduction focuses on how to build integrated solutions to industrial vision problems from individual algorithms. It gives a hands-on guide for setting up automated visual inspection systems using the NeuroCheck software package.

  12. Cell cycle control in Alphaproteobacteria.

    Science.gov (United States)

    Collier, Justine

    2016-04-01

    Alphaproteobacteria include many medically and environmentally important organisms. Despite the diversity of their niches and lifestyles, from free-living to host-associated, they usually rely on very similar mechanisms to control their cell cycles. Studies on Caulobacter crescentus still lay the foundation for understanding the molecular details of pathways regulating DNA replication and cell division and coordinating these two processes with other events of the cell cycle. This review highlights recent discoveries on the regulation and the mode of action of conserved global regulators and small molecules like c-di-GMP and (p)ppGpp, which play key roles in cell cycle control. It also describes several newly identified mechanisms that modulate cell cycle progression in response to stresses or environmental conditions. PMID:26871482

  13. Visual cells remember earlier applied target: plasticity of orientation selectivity.

    Directory of Open Access Journals (Sweden)

    Narcis Ghisovan

    Full Text Available BACKGROUND: A canonical proposition states that, in mature brain, neurons responsive to sensory stimuli are tuned to specific properties installed shortly after birth. It is amply demonstrated that that neurons in adult visual cortex of cats are orientation-selective that is they respond with the highest firing rates to preferred oriented stimuli. METHODOLOGY/PRINCIPAL FINDINGS: In anesthetized cats, prepared in a conventional fashion for single cell recordings, the present investigation shows that presenting a stimulus uninterruptedly at a non-preferred orientation for twelve minutes induces changes in orientation preference. Across all conditions orientation tuning curves were investigated using a trial by trial method. Contrary to what has been previously reported with shorter adaptation duration, twelve minutes of adaptation induces mostly attractive shifts, i.e. toward the adapter. After a recovery period allowing neurons to restore their original orientation tuning curves, we carried out a second adaptation which produced three major results: (1 more frequent attractive shifts, (2 an increase of their magnitude, and (3 an additional enhancement of responses at the new or acquired preferred orientation. Additionally, we also show that the direction of shifts depends on the duration of the adaptation: shorter adaptation in most cases produces repulsive shifts, whereas adaptation exceeding nine minutes results in attractive shifts, in the same unit. Consequently, shifts in preferred orientation depend on the duration of adaptation. CONCLUSION/SIGNIFICANCE: The supplementary response improvements indicate that neurons in area 17 keep a memory trace of the previous stimulus properties, thereby upgrading cellular performance. It also highlights the dynamic nature of basic neuronal properties in adult cortex since repeated adaptations modified both the orientation tuning selectivity and the response strength to the preferred orientation. These

  14. Research on visual modeling and simulation of control system in nuclear power plant

    International Nuclear Information System (INIS)

    A block diagram-oriented visual modeling and simulating software is developed and corresponding mathematical models of control system are solved by the discrete similarity method. This software can be used to model and simulate control system in nuclear power plant conveniently, rapidly and accurately in visual mode. Some satisfactory results are obtained. The research works will be of well referential and applied value to the design and analysis of control system in nuclear power plant

  15. Endothelial cell-initiated extravasation of cancer cells visualized in zebrafish

    Directory of Open Access Journals (Sweden)

    Masamitsu Kanada

    2014-12-01

    Full Text Available The extravasation of cancer cells, a key step for distant metastasis, is thought to be initiated by disruption of the endothelial barrier by malignant cancer cells. An endothelial covering-type extravasation of cancer cells in addition to conventional cancer cell invasion-type extravasation was dynamically visualized in a zebrafish hematogenous metastasis model. The inhibition of VEGF-signaling impaired the invasion-type extravasation via inhibition of cancer cell polarization and motility. Paradoxically, the anti-angiogenic treatment showed the promotion, rather than the inhibition, of the endothelial covering-type extravasation of cancer cells, with structural changes in the endothelial walls. These findings may be a set of clues to the full understanding of the metastatic process as well as the metastatic acceleration by anti-angiogenic reagents observed in preclinical studies.

  16. Robot vision language RVL/V: An integration scheme of visual processing and manipulator control

    International Nuclear Information System (INIS)

    RVL/V is a robot vision language designed to write a program for visual processing and manipulator control of a hand-eye system. This paper describes the design of RVL/V and the current implementation of the system. Visual processing is performed on one-dimensional range data of the object surface. Model-based instructions execute object detection, measurement and view control. The hierarchy of visual data and processing is introduced to give RVL/V generality. A new scheme to integrate visual information and manipulator control is proposed. The effectiveness of the model-based visual processing scheme based on profile data is demonstrated by a hand-eye experiment

  17. Visual inspections of the neutron absorber control rods of the IEA-R1 reactor

    International Nuclear Information System (INIS)

    The Fuel Engineering Division at IPEN/CNEN-SP developed facilities for visual inspection of the IEA-R1 fuel elements and neutron absorbing control rod assemblies inside the research reactor pool. This work presents the method of visual inspection performed at IEA-R1 research reactor. These inspections were adopted to evaluate and to follow the state of the Ag-In-Cd control assemblies fabricated at CERCA in 1972 that remain in use at the reactor core. In 1998, 2000 and 20001, visual inspections were performed in these control rod assemblies, which the general conditions were evaluated. (author)

  18. The Impact of Baseline Trend Control on Visual Analysis of Single-Case Data

    Science.gov (United States)

    Mercer, Sterett H.; Sterling, Heather E.

    2012-01-01

    The impact of baseline trend control on visual analyses of AB intervention graphs was examined with simulated data at various values of baseline trend, autocorrelation, and effect size. Participants included 202 undergraduate students with minimal training in visual analysis and 10 graduate students and faculty with more training and experience in…

  19. Control of Visual Selection during Visual Search in the Human Brain

    OpenAIRE

    Olma, Manuel C.; Donner, Tobias H.; Brandt, Stephan A.

    2007-01-01

    How do we find a target object in a cluttered visual scene? Targets carrying unique salient features can be found in parallel without directing attention, whereas targets defined by feature conjunctions or non-salient features need to be scrutinized in a serial attentional process in order to be identified. In this article, we review a series of experiments in which we used fMRI to probe the neural basis of this active search process in the human brain. In all experiments, we compared the fMR...

  20. Visual control of an action discrimination in pigeons.

    Science.gov (United States)

    Qadri, Muhammad A J; Asen, Yael; Cook, Robert G

    2014-01-01

    Recognizing and categorizing behavior is essential for all animals. The visual and cognitive mechanisms underlying such action discriminations are not well understood, especially in nonhuman animals. To identify the visual bases of action discriminations, four pigeons were tested in a go/no-go procedure to examine the contribution of different visual features in a discrimination of walking and running actions by different digital animal models. Two different tests with point-light displays derived from studies of human biological motion failed to support transfer of the learned action discrimination from fully figured models. Tests with silhouettes, contours, and the selective deletion or occlusion of different parts of the models indicated that information about the global motions of the entire model was critical to the discrimination. This outcome, along with earlier results, suggests that the pigeons’ discrimination of these locomotive actions involved a generalized categorization of the sequence of configural poses. Because the motor systems for locomotion and flying in pigeons share little in common with quadruped motions, the pigeons’ discrimination of these behaviors creates problems for motor theories of action recognition based on mirror neurons or related notions of embodied cognition. It suggests instead that more general motion and shape mechanisms are sufficient for making such discriminations, at least in birds. PMID:24879863

  1. Experimental System for Investigation of Visual Sensory Input in Postural Feedback Control

    Directory of Open Access Journals (Sweden)

    Jozef Pucik

    2012-01-01

    Full Text Available The human postural control system represents a biological feedback system responsible for maintenance of upright stance. Vestibular, proprioceptive and visual sensory inputs provide the most important information into the control system, which controls body centre of mass (COM in order to stabilize the human body resembling an inverted pendulum. The COM can be measured indirectly by means of a force plate as the centre of pressure (COP. Clinically used measurement method is referred to as posturography. In this paper, the conventional static posturography is extended by visual stimulation, which provides insight into a role of visual information in balance control. Visual stimuli have been designed to induce body sway in four specific directions – forward, backward, left and right. Stabilograms were measured using proposed single-PC based system and processed to calculate velocity waveforms and posturographic parameters. The parameters extracted from pre-stimulus and on-stimulus periods exhibit statistically significant differences.

  2. Visual Problem Solving and Self‐regulation in Training Air Traffic Control

    OpenAIRE

    Meeuwen van, Ludo

    2015-01-01

    Van Meeuwen, L. W. (2013). Visual problem solving and self-regulation in training air traffic control (Unpublished doctoral dissertation). Centre for Learning Sciences and Technologies, Open Universiteit, Heerlen, The Netherlands.

  3. Visual problem solving and self-regulation in training air traffic control

    NARCIS (Netherlands)

    Van Meeuwen, Ludo

    2013-01-01

    Van Meeuwen, L. W. (2013). Visual problem solving and self-regulation in training air traffic control (Unpublished doctoral dissertation). Centre for Learning Sciences and Technologies, Open Universiteit, Heerlen, The Netherlands.

  4. A Robot-Assisted Cell Manipulation System with an Adaptive Visual Servoing Method

    Directory of Open Access Journals (Sweden)

    Yu Xie

    2016-06-01

    Full Text Available Robot-assisted cell manipulation is gaining attention for its ability in providing high throughput and high precision cell manipulation for the biological industry. This paper presents a visual servo microrobotic system for cell microinjection. We investigated the automatic cell autofocus method that reduced the complexity of the system. Then, we produced an adaptive visual processing algorithm to detect the location of the cell and micropipette toward the uneven illumination problem. Fourteen microinjection experiments were conducted with zebrafish embryos. A 100% success rate was achieved either in autofocus or embryo detection, which verified the robustness of the proposed automatic cell manipulation system.

  5. Experience of in-cell visual inspection using CCD camera in hot cell of Reprocessing Plant

    International Nuclear Information System (INIS)

    This paper describes the selection, customization and operating experience of the visual inspection system for the hot cell of a Reprocessing Plant. For process equipment such as fuel chopping machine, dissolver, centrifuge, centrifugal extractors etc., viewing of operations and maintenance using manipulators is required. For this, the service of in-cell camera is essential. The ambience of the hot cell of Compact facility for Reprocessing of Advanced fuels in Lead cell (CORAL) for the reprocessing of fast reactor spent fuel has high gamma radiation and acidic vapors. Black and white Charge Coupled Device (CCD) camera has been used in CORAL incorporating in-house modifications to suit the operating ambient conditions, thereby extending the operating life of the camera. (author)

  6. Vascular Cell Induction Culture System Using Arabidopsis Leaves (VISUAL) Reveals the Sequential Differentiation of Sieve Element-Like Cells.

    Science.gov (United States)

    Kondo, Yuki; Nurani, Alif Meem; Saito, Chieko; Ichihashi, Yasunori; Saito, Masato; Yamazaki, Kyoko; Mitsuda, Nobutaka; Ohme-Takagi, Masaru; Fukuda, Hiroo

    2016-06-01

    Cell differentiation is a complex process involving multiple steps, from initial cell fate specification to final differentiation. Procambial/cambial cells, which act as vascular stem cells, differentiate into both xylem and phloem cells during vascular development. Recent studies have identified regulatory cascades for xylem differentiation. However, the molecular mechanism underlying phloem differentiation is largely unexplored due to technical challenges. Here, we established an ectopic induction system for phloem differentiation named Vascular Cell Induction Culture System Using Arabidopsis Leaves (VISUAL). Our results verified similarities between VISUAL-induced Arabidopsis thaliana phloem cells and in vivo sieve elements. We performed network analysis using transcriptome data with VISUAL to dissect the processes underlying phloem differentiation, eventually identifying a factor involved in the regulation of the master transcription factor gene APL Thus, our culture system opens up new avenues not only for genetic studies of phloem differentiation, but also for future investigations of multidirectional differentiation from vascular stem cells. PMID:27194709

  7. Visual Control of Autonomous Vehicle by Neural Networks Using Fuzzy-Supervised Learning

    Energy Technology Data Exchange (ETDEWEB)

    Ryoo, Young Jae [Kumho Information and Telecommunications Laboratory, Kwangju (Korea, Republic of); Lim, Young Cheol [Cheonnam National University, Kwangju (Korea, Republic of)

    1997-04-01

    This paper describes a control scheme for an autonomous vehicle with visual sensors, which uses visual information to guide itself along roadways. The control system integrates visual data into the steering servo process directly, instead of subdividing the process by geometric reasoning for a vehicle-centered representation of the road from two-dimensional visual image data. A neural network using fuzzy-supervised learning is used for determining the steering angle required to move the vanishing point and vanishing line of the road to the desired position in the camera image. The validity and the effectiveness of the proposed control scheme are confirmed by a computer simulation of the autonomous vehicle`s driving performance. (author). 12 refs., 8 figs., 4 tabs.

  8. The role of cell adhesion molecules in visual circuit formation: from neurite outgrowth to maps and synaptic specificity.

    Science.gov (United States)

    Missaire, Mégane; Hindges, Robert

    2015-06-01

    The formation of visual circuitry is a multistep process that involves cell-cell interactions based on a range of molecular mechanisms. The correct implementation of individual events, including axon outgrowth and guidance, the formation of the topographic map, or the synaptic targeting of specific cellular subtypes, are prerequisites for a fully functional visual system that is able to appropriately process the information captured by the eyes. Cell adhesion molecules (CAMs) with their adhesive properties and their high functional diversity have been identified as key actors in several of these fundamental processes. Because of their growth-promoting properties, CAMs play an important role in neuritogenesis. Furthermore, they are necessary to control additional neurite development, regulating dendritic spacing and axon pathfinding. Finally, trans-synaptic interactions of CAMs ensure cell type-specific connectivity as a basis for the establishment of circuits processing distinct visual features. Recent discoveries implicating CAMs in novel mechanisms have led to a better general understanding of neural circuit formation, but also revealed an increasing complexity of their function. This review aims at describing the different levels of action for CAMs to shape neural connectivity, with a special focus on the visual system. PMID:25649254

  9. Effect of visual biofeedback to acquire supraglottic swallow in healthy individuals: a randomized-controlled trial.

    Science.gov (United States)

    Imada, Miho; Kagaya, Hitoshi; Ishiguro, Yuriko; Kato, Miho; Inamoto, Yoko; Tanaka, Takashi; Shibata, Seiko; Saitoh, Eiichi

    2016-06-01

    The aim of this study is to evaluate the effect of visual biofeedback therapy in acquiring supraglottic swallow (SGS) in a randomized-controlled trial with healthy individuals. Eighteen individuals (mean age, 26 years) who could not close or keep closed the vocal folds before and during the swallow in SGS were allocated randomly to either a visual biofeedback group (eight individuals) or a nonbiofeedback group (10 individuals). A videoendoscope was inserted intranasally and an SGS exercise, using 4 ml of green-colored water, was performed 30 times per day up to 5 days. When the participant failed to perform SGS, the result was provided only to the participants in the visual biofeedback group. The median length of time until acquiring SGS was 1.5 days in the visual biofeedback group and 3.5 days in the nonbiofeedback group (P=0.040). We concluded that visual biofeedback effectively enabled participants to acquire SGS earlier. PMID:26795716

  10. Design of visually and remotely controlled mirror box platform in BSRF

    International Nuclear Information System (INIS)

    In this paper, we report a mirror box platform for controlling the beamline mirrors in visual and remote mode at Beijing Synchrotron Radiation Facility (BSRF). The platform is based on Client/Device Server structure and, to ensure the safety, only the clients examined by Server can access the devices. The 3D mirror adjustments and simple ASCII message protocol are designed for implement of the platform control in visual and remote mode. Test results show that the time to update the position status is 0.2 s and the position error in visual control is less than 5%. The performance meets requirements of the mirror box control in BSRF beam lines. By increasing the device drivers in the server and developing programs in the clients, the platform can be used to control the whole beam line. (authors)

  11. Hybrid Visual Servoing Control for Robotic Arc Welding Based on Structured Light Vision

    Institute of Scientific and Technical Information of China (English)

    XUDe; WANGLin-Kun; TUZhi-Guo; TANMin

    2005-01-01

    A novel hybrid visual servoing control method based on structured light vision is proposed for robotic arc welding with a general six degrees of freedom robot. It consists of a position control inner-loop in Cartesian space and two outer-loops. One is position-based visual control inCartesian space for moving in the direction of weld seam, i.e., weld seam tracking, another is imagebased visual control in image space for adjustment to eliminate the errors in the process of tracking.A new Jacobian matrix from image space of the feature point on structured light stripe to Cartesian space is provided for differential movement of the end-effector. The control system model is simplified and its stability is discussed. An experiment of arc welding protected by gas CO2 for verifying is well conducted.

  12. A method of initial welding position guiding for arc welding robot based on visual servo control

    Institute of Scientific and Technical Information of China (English)

    郭振民; 陈善本; 邱涛; 吴林

    2003-01-01

    In order to solve the visual guiding task of initial welding position for arc welding robot, this paper presents a practice-prone image-based visual servo control strategy without calibration, and we perform validating experiments on a nine-DOF arc welding robot system. Experimental results illustrate presented method has the function to fulfill the task of welding robot initial positioning with certain anti-jamming ability. This method provides a basis for guiding welding gun to initial welding pose with real typical seam's image properties to replace flag block properties, and is a significant exploit to realize visual guiding of initial welding position and seam tracing in robot welding system.

  13. Control Framework for Dexterous Manipulation Using Dynamic Visual Servoing and Tactile Sensors’ Feedback

    Directory of Open Access Journals (Sweden)

    Carlos A. Jara

    2014-01-01

    Full Text Available Tactile sensors play an important role in robotics manipulation to perform dexterous and complex tasks. This paper presents a novel control framework to perform dexterous manipulation with multi-fingered robotic hands using feedback data from tactile and visual sensors. This control framework permits the definition of new visual controllers which allow the path tracking of the object motion taking into account both the dynamics model of the robot hand and the grasping force of the fingertips under a hybrid control scheme. In addition, the proposed general method employs optimal control to obtain the desired behaviour in the joint space of the fingers based on an indicated cost function which determines how the control effort is distributed over the joints of the robotic hand. Finally, authors show experimental verifications on a real robotic manipulation system for some of the controllers derived from the control framework.

  14. Visualization and heat/mass transfer study of laminar channel flow controlled by synthetic jet array

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Zdeněk; Dančová, Petra; Vít, Tomáš

    Kaohsiung : National Pingtung University of Science and Technolog, 2009 - (Tai, C.), 32B-2-32B-2 ISBN N. [Pacific Symposium on Flow Visualization and Image Processing /7./ (PSFVIP-7 2009). Kaohsiung (TW), 16.11.2009-19.11.2009] R&D Projects: GA AV ČR(CZ) IAA200760801; GA AV ČR(CZ) IAA200760504 Institutional research plan: CEZ:AV0Z20760514 Keywords : flow control * synthetic jet * visualization Subject RIV: BK - Fluid Dynamics

  15. Early depolarizing GABA controls critical period plasticity in the rat visual cortex

    OpenAIRE

    Deidda, Gabriele; Allegra, Manuela; Cerri, Chiara; Naskar, Shovan; Bony, Guillaume; Zunino, Giulia; Bozzi, Yuri; Caleo, Matteo; Cancedda, Laura

    2014-01-01

    SUMMARY Hyperpolarizing and inhibitory GABA regulates “critical periods” for plasticity in sensory cortices. Here, we examine the role of early, depolarizing GABA in controlling plasticity mechanisms. We report that brief interference with depolarizing GABA during early development prolonged critical period plasticity in visual cortical circuits, without affecting overall development of the visual system. The effects on plasticity were accompanied by dampened inhibitory neurotransmission, dow...

  16. Combining Dense Structure From Motion and Visual SLAM in a Behavior-Based Robot Control Architecture

    OpenAIRE

    Geert De Cubber; Sid Ahmed Berrabah; Daniela Doroftei; Yvan Baudoin; Hichem Sahli

    2010-01-01

    In this paper, we present a control architecture for an intelligent outdoor mobile robot. This enables the robot to navigate in a complex, natural outdoor environment, relying on only a single on-board camera as sensory input. This is achieved through a twofold analysis of the visual data stream: a dense structure from motion algorithm calculates a depth map of the environment and a visual simultaneous localization and mapping algorithm builds a map of the surroundings using image features. T...

  17. Fuzzy control system for thermal and visual comfort in building

    Energy Technology Data Exchange (ETDEWEB)

    Kristl, Ziva; Kosir, Mitja; Trobec Lah, Mateja; Krainer, Ales [Faculty of Civil and Geodetic Engineering, Chair for Buildings and Constructional Complexes, University of Ljubljana, Jamova cesta 2, 1000 Ljubljana (Slovenia)

    2008-04-15

    In the era of informational and technological breakthrough, the automatically controlled living and working environment is expected to become a commonly used service. This paper deals with dynamically controlled thermal and illumination responses of built environment in real-time conditions. The aim is to harmonize thermal and optical behaviour of a building by coordinating energy flows that pass through the transparent part of the envelope. For this purpose, a test chamber with an opening on the southern side was built. Changeable geometry of the opening is achieved by the automated external roller blind. A fuzzy control system enables the positioning of the shading device according to the desired indoor set points and the outdoor conditions. Through the experiments, the fuzzy controllers were tuned and gradually improved. Some sets of the experiments are presented here to illustrate the process. (author)

  18. Fuzzy control system for thermal and visual comfort in building

    OpenAIRE

    Krainer, Aleš; Košir, Mitja; Kristl, Živa; Trobec Lah, Mateja

    2016-01-01

    In the era of informational and technological breakthrough, the automatically controlled living and working environment is expected to become a commonly used service. This paper deals with dynamically controlled thermal and illumination responses of built environment in real-time conditions. The aim is to harmonize thermal and optical behaviour of a building by coordinating energy flows that pass through the transparent part of the envelope. For this purpose, a test chamber with an opening on...

  19. Visual servoing and force control fusion for complex insertion tasks

    OpenAIRE

    Pomares Baeza, Jorge; Torres Medina, Fernando; Gil Vázquez, Pablo

    2007-01-01

    Comunicación presentada en el 11th International Conference on Advanced Robotics, June 30-July 3, 2003, University of Coimbra, Portugal To have access to force sensing is indispensable element for applications in which robots interact directly with objects in external settings. The very nature and the limited accuracy of the vision systems used for position control, implies that these types of systems are not adequate for controlling the interaction of the robot with its set...

  20. Improved MOGA-tuning and visualization for a hybrid control system

    OpenAIRE

    Stirrup, R.; Chipperfield, A.J.

    2005-01-01

    A hybrid controller is developed for a solar-thermal power plant using a gain-scheduled controller with feedforward to control the more linear operating regimes and a fuzzy PI incremental controller for the highly nonlinear operating region of the plant. An enhanced method of MOGA-tuning is employed by first optimizing the number of input/output membership functions using neuro-fuzzy data clustering. Enhancements to the visualization properties of the MOGA's graphical user interface are evalu...

  1. Influence of visual feedback on dynamic balance control in chronic stroke survivors.

    Science.gov (United States)

    Walker, Eric R; Hyngstrom, Allison S; Schmit, Brian D

    2016-03-21

    Chronic stroke survivors have an increased incidence of falls during walking, suggesting changes in dynamic balance control post-stroke. Despite this increased incidence of falls during walking, balance control is often studied only in standing. The purpose of this study was to quantify deficits in dynamic balance control during walking, and to evaluate the influence of visual feedback on this control in stroke survivors. Ten individuals with chronic stroke, and ten neurologically intact individuals participated in this study. Walking performance was assessed while participants walked on an instrumented split-belt treadmill with different types of visual feedback. Dynamic balance control was quantified using both the extent of center of mass (COM) movement in the frontal plane over a gait cycle (COM sway), and base of support (step width). Stroke survivors walked with larger COM sway and wider step widths compared to controls. Despite these baseline differences, both groups walked with a similar ratio of step width to COM sway (SW/COM). Providing a stationary target with a laser reference of body movement reduced COM sway only in the stroke group, indicating that visual feedback of sway alters dynamic balance control post-stroke. These results demonstrate that stroke survivors attempt to maintain a similar ratio of step width to COM movement, and visual cues can be used to help control COM movement during walking post-stroke. PMID:26916509

  2. Lateral Inhibition in the Human Visual System in Patients with Glaucoma and Healthy Subjects: A Case-Control Study.

    Science.gov (United States)

    Junoy Montolio, Francisco G; Meems, Wilma; Janssens, Marieke S A; Stam, Lucas; Jansonius, Nomdo M

    2016-01-01

    In glaucoma, the density of retinal ganglion cells is reduced. It is largely unknown how this influences retinal information processing. An increase in spatial summation and a decrease in contrast gain control and contrast adaptation have been reported. A decrease in lateral inhibition might also arise. This could result in a larger than expected response to some stimuli, which could mask ganglion cell loss on functional testing (structure-function discrepancy). The aim of this study was to compare lateral inhibition between glaucoma patients and healthy subjects; we used a case-control design. Cases (n = 18) were selected to have advanced visual field loss in combination with a normal visual acuity. Controls (n = 50) were not allowed to have symptoms or signs of any eye disease. Lateral inhibition was measured psychophysically on a computer screen, with (1) a modified illusory movement experiment and (2) a contrast sensitivity (CS) test. Illusory movement was quantified by nulling it with a real movement; measure of lateral inhibition was the amount of illusory movement. CS was measured at 1 and 4 cycles per degree (cpd); measure of lateral inhibition was the difference between log CS at 4 and 1 cpd. Both measures were compared between cases and controls; analyses were adjusted for age and gender. There was no difference between cases and controls for these two measures of lateral inhibition (p = 0.58 for illusory movement; p = 0.20 for CS). The movement threshold was higher in cases than in controls (p = 0.008) and log CS was lower, at both 1 (-0.20; p = 0.008) and 4 (-0.28; p = 0.001) cpd. Our results indicate that spatially antagonistic mechanisms are not specifically affected in glaucoma, at least not in the intact center of a severely damaged visual field. This suggests that the structure-function discrepancy in glaucoma is not related to a decrease in lateral inhibition. PMID:26953590

  3. Radiation therapy for primary carcinoma of the eyelid. Tumor control and visual function

    International Nuclear Information System (INIS)

    Background and purpose: Surgical excision remains the standard and most reliable curative treatment for eyelid carcinoma, but frequently causes functional and cosmetic impairment of the eyelid. We therefore investigated the efficacy and safety of radiation therapy in eyelid carcinoma. Patients and methods: Twenty-three patients with primary carcinoma of the eyelid underwent radiation therapy. Sebaceous carcinoma was histologically confirmed in 16 patients, squamous cell carcinoma in 6, and basal cell carcinoma in 1. A total dose of 50-66.6 Gy (median, 60 Gy) was delivered to tumor sites in 18-37 fractions (median, 30 fractions). Results: All but 3 of the 23 patients had survived at a median follow-up period of 49 months. The overall survival and local progression-free rates were 87% and 93% at 2 years, and 80% and 93% at 5 years, respectively. Although radiation-induced cataracts developed in 3 patients, visual acuity in the other patients was relatively well preserved. There were no other therapy-related toxicities of grade 3 or greater. Conclusion: Radiation therapy is safe and effective for patients with primary carcinoma of the eyelid. It appears to contribute to prolonged survival as a result of good tumor control, and it also facilitates functional and cosmetic preservation of the eyelid. (orig.)

  4. Radiation therapy for primary carcinoma of the eyelid. Tumor control and visual function

    Energy Technology Data Exchange (ETDEWEB)

    Hata, M.; Koike, I.; Odagiri, K.; Kasuya, T.; Minagawa, Y.; Kaizu, H.; Mukai, Y.; Inoue, T. [Yokohama City Univ. Graduate School of Medicine, Kanagawa (Japan). Dept. of Radiology; Maegawa, J. [Yokohama City Univ. Graduate School of Medicine, Kanagawa (Japan). Dept. of Plastic and Reconstructive Surgery; Kaneko, A. [Yokohama City Univ. Graduate School of Medicine, Kanagawa (Japan). Dept. of Ophthalmology

    2012-12-15

    Background and purpose: Surgical excision remains the standard and most reliable curative treatment for eyelid carcinoma, but frequently causes functional and cosmetic impairment of the eyelid. We therefore investigated the efficacy and safety of radiation therapy in eyelid carcinoma. Patients and methods: Twenty-three patients with primary carcinoma of the eyelid underwent radiation therapy. Sebaceous carcinoma was histologically confirmed in 16 patients, squamous cell carcinoma in 6, and basal cell carcinoma in 1. A total dose of 50-66.6 Gy (median, 60 Gy) was delivered to tumor sites in 18-37 fractions (median, 30 fractions). Results: All but 3 of the 23 patients had survived at a median follow-up period of 49 months. The overall survival and local progression-free rates were 87% and 93% at 2 years, and 80% and 93% at 5 years, respectively. Although radiation-induced cataracts developed in 3 patients, visual acuity in the other patients was relatively well preserved. There were no other therapy-related toxicities of grade 3 or greater. Conclusion: Radiation therapy is safe and effective for patients with primary carcinoma of the eyelid. It appears to contribute to prolonged survival as a result of good tumor control, and it also facilitates functional and cosmetic preservation of the eyelid. (orig.)

  5. Iterative development of visual control systems in a research vivarium.

    Science.gov (United States)

    Bassuk, James A; Washington, Ida M

    2014-01-01

    The goal of this study was to test the hypothesis that reintroduction of Continuous Performance Improvement (CPI) methodology, a lean approach to management at Seattle Children's (Hospital, Research Institute, Foundation), would facilitate engagement of vivarium employees in the development and sustainment of a daily management system and a work-in-process board. Such engagement was implemented through reintroduction of aspects of the Toyota Production System. Iterations of a Work-In-Process Board were generated using Shewhart's Plan-Do-Check-Act process improvement cycle. Specific attention was given to the importance of detecting and preventing errors through assessment of the following 5 levels of quality: Level 1, customer inspects; Level 2, company inspects; Level 3, work unit inspects; Level 4, self-inspection; Level 5, mistake proofing. A functioning iteration of a Mouse Cage Work-In-Process Board was eventually established using electronic data entry, an improvement that increased the quality level from 1 to 3 while reducing wasteful steps, handoffs and queues. A visual workplace was realized via a daily management system that included a Work-In-Process Board, a problem solving board and two Heijunka boards. One Heijunka board tracked cage changing as a function of a biological kanban, which was validated via ammonia levels. A 17% reduction in cage changing frequency provided vivarium staff with additional time to support Institute researchers in their mutual goal of advancing cures for pediatric diseases. Cage washing metrics demonstrated an improvement in the flow continuum in which a traditional batch and queue push system was replaced with a supermarket-type pull system. Staff engagement during the improvement process was challenging and is discussed. The collective data indicate that the hypothesis was found to be true. The reintroduction of CPI into daily work in the vivarium is consistent with the 4P Model of the Toyota Way and selected Principles

  6. Iterative development of visual control systems in a research vivarium.

    Directory of Open Access Journals (Sweden)

    James A Bassuk

    Full Text Available The goal of this study was to test the hypothesis that reintroduction of Continuous Performance Improvement (CPI methodology, a lean approach to management at Seattle Children's (Hospital, Research Institute, Foundation, would facilitate engagement of vivarium employees in the development and sustainment of a daily management system and a work-in-process board. Such engagement was implemented through reintroduction of aspects of the Toyota Production System. Iterations of a Work-In-Process Board were generated using Shewhart's Plan-Do-Check-Act process improvement cycle. Specific attention was given to the importance of detecting and preventing errors through assessment of the following 5 levels of quality: Level 1, customer inspects; Level 2, company inspects; Level 3, work unit inspects; Level 4, self-inspection; Level 5, mistake proofing. A functioning iteration of a Mouse Cage Work-In-Process Board was eventually established using electronic data entry, an improvement that increased the quality level from 1 to 3 while reducing wasteful steps, handoffs and queues. A visual workplace was realized via a daily management system that included a Work-In-Process Board, a problem solving board and two Heijunka boards. One Heijunka board tracked cage changing as a function of a biological kanban, which was validated via ammonia levels. A 17% reduction in cage changing frequency provided vivarium staff with additional time to support Institute researchers in their mutual goal of advancing cures for pediatric diseases. Cage washing metrics demonstrated an improvement in the flow continuum in which a traditional batch and queue push system was replaced with a supermarket-type pull system. Staff engagement during the improvement process was challenging and is discussed. The collective data indicate that the hypothesis was found to be true. The reintroduction of CPI into daily work in the vivarium is consistent with the 4P Model of the Toyota Way and

  7. Three dimensional visualization to support command and control

    Energy Technology Data Exchange (ETDEWEB)

    Van Slambrook, G.A.

    1997-04-01

    Virtual reality concepts are changing the way one thinks about and with computers. The concepts have already proven their potential usefulness in a broad range of applications. This research was concerned with exploring and demonstrating the utility of virtual reality in robotics and satellite command and control applications. The robotics work addressed the need to quickly build accurate graphical models of physical environments by allowing a user to interactively build a model of a remote environment by superimposing stereo graphics onto live stereo video. The satellite work addressed the fusion of multiple data sets or models into one synergistic display for more effective training, design, and command and control of satellite systems.

  8. Soft-computing based visual control for unmanned vehicles

    OpenAIRE

    Olivares Méndez, Miguel Ángel

    2013-01-01

    El objetivo principal de esta Tesis es extender la utilización del “Soft- Computing” para el control de vehículos sin piloto utilizando visión. Este trabajo va más allá de los típicos sistemas de control utilizados en entornos altamente controlados, demonstrando la fuerza y versatilidad de la lógica difusa (Fuzzy Logic) para controlar vehículos aéreos y terrestres en un abanico de applicaciones diferentes. Para esta Tesis se ha realizado un gran número de pruebas reales en las cuales los cont...

  9. Three dimensional visualization to support command and control

    International Nuclear Information System (INIS)

    Virtual reality concepts are changing the way one thinks about and with computers. The concepts have already proven their potential usefulness in a broad range of applications. This research was concerned with exploring and demonstrating the utility of virtual reality in robotics and satellite command and control applications. The robotics work addressed the need to quickly build accurate graphical models of physical environments by allowing a user to interactively build a model of a remote environment by superimposing stereo graphics onto live stereo video. The satellite work addressed the fusion of multiple data sets or models into one synergistic display for more effective training, design, and command and control of satellite systems

  10. Model of visual contrast gain control and pattern masking

    Science.gov (United States)

    Watson, A. B.; Solomon, J. A.

    1997-01-01

    We have implemented a model of contrast gain and control in human vision that incorporates a number of key features, including a contrast sensitivity function, multiple oriented bandpass channels, accelerating nonlinearities, and a devisive inhibitory gain control pool. The parameters of this model have been optimized through a fit to the recent data that describe masking of a Gabor function by cosine and Gabor masks [J. M. Foley, "Human luminance pattern mechanisms: masking experiments require a new model," J. Opt. Soc. Am. A 11, 1710 (1994)]. The model achieves a good fit to the data. We also demonstrate how the concept of recruitment may accommodate a variant of this model in which excitatory and inhibitory paths have a common accelerating nonlinearity, but which include multiple channels tuned to different levels of contrast.

  11. Goal-oriented Data Visualization with Software Project Control Centers

    OpenAIRE

    Heidrich, Jens; Münch, Jürgen

    2014-01-01

    Many software development organizations still lack support for obtaining intellectual control over their software development processes and for determining the performance of their processes and the quality of the produced products. Systematic support for detecting and reacting to critical project states in order to achieve planned goals is usually missing. One means to institutionalize measurement on the basis of explicit models is the development and establishment of a so-called Software Pr...

  12. Visualization and orchestration of the dynamic molecular society in cells

    Institute of Scientific and Technical Information of China (English)

    Xuebiao Yao; Guowei Fang

    2009-01-01

    @@ Visualization of specific molecules and their interactions in real space and time is essential to delineate how cellular plasticity and dynamics are achieved and orchestrated as perturbation of cellular plasticity and dynamics is detrimental to health. Elucidation of cellular dynamics requires molecular imaging at nanometer scale at millisecond resolution. The 1st International Conference on Cellular Dynamics and Chemical Biology held in Hefei, China (from 12 September to 15 September,2008) launched the quest by bringing synergism among photonics, chemistry and biology.

  13. Pineal photoreceptor cells are required for maintaining the circadian rhythms of behavioral visual sensitivity in zebrafish.

    Directory of Open Access Journals (Sweden)

    Xinle Li

    Full Text Available In non-mammalian vertebrates, the pineal gland functions as the central pacemaker that regulates the circadian rhythms of animal behavior and physiology. We generated a transgenic zebrafish line [Tg(Gnat2:gal4-VP16/UAS:nfsB-mCherry] in which the E. coli nitroreductase is expressed in pineal photoreceptor cells. In developing embryos and young adults, the transgene is expressed in both retinal and pineal photoreceptor cells. During aging, the expression of the transgene in retinal photoreceptor cells gradually diminishes. By 8 months of age, the Gnat2 promoter-driven nitroreductase is no longer expressed in retinal photoreceptor cells, but its expression in pineal photoreceptor cells persists. This provides a tool for selective ablation of pineal photoreceptor cells, i.e., by treatments with metronidazole. In the absence of pineal photoreceptor cells, the behavioral visual sensitivity of the fish remains unchanged; however, the circadian rhythms of rod and cone sensitivity are diminished. Brief light exposures restore the circadian rhythms of behavioral visual sensitivity. Together, the data suggest that retinal photoreceptor cells respond to environmental cues and are capable of entraining the circadian rhythms of visual sensitivity; however, they are insufficient for maintaining the rhythms. Cellular signals from the pineal photoreceptor cells may be required for maintaining the circadian rhythms of visual sensitivity.

  14. Visualizing and quantifying cell phenotype using soft X-ray tomography

    OpenAIRE

    McDermott, Gerry; Fox, Douglas M.; Epperly, Lindsay; Wetzler, Modi; Barron, Annelise E.; Le Gros, Mark A.; Larabell, Carolyn A.

    2012-01-01

    Soft X-ray tomography (SXT) is an imaging technique capable of characterizing and quantifying the structural phenotype of cells. In particular, SXT is used to visualize the internal architecture of fully hydrated, intact eukaryotic and prokaryotic cells at high spatial resolution (50 nm or better). Image contrast in SXT is derived from the biochemical composition of the cell, and obtained without the need to use potentially damaging contrast-enhancing agents, such as heavy metals. The cells a...

  15. Xenopus laevis retinal ganglion cell dendritic arbors develop independently of visual stimulation

    OpenAIRE

    Barbara Lom; Rebecca L. Rigel

    2004-01-01

    Newly formed neurons must locate their appropriate target cells and then form synaptic connections with these targets in order to establish a functional nervous system. In the vertebrate retina, retinal ganglion cell (RGC) dendrites extend from the cell body and form synapses with nearby amacrine and bipolar cells. RGC axons, however, exit the retina and synapse with the dendrites of midbrain neurons in the optic tectum. We examined how visual stimulation influenced Xenopus RGC dendritic arbo...

  16. Influence of combined visual and vestibular cues on human perception and control of horizontal rotation

    Science.gov (United States)

    Zacharias, G. L.; Young, L. R.

    1981-01-01

    Measurements are made of manual control performance in the closed-loop task of nulling perceived self-rotation velocity about an earth-vertical axis. Self-velocity estimation is modeled as a function of the simultaneous presentation of vestibular and peripheral visual field motion cues. Based on measured low-frequency operator behavior in three visual field environments, a parallel channel linear model is proposed which has separate visual and vestibular pathways summing in a complementary manner. A dual-input describing function analysis supports the complementary model; vestibular cues dominate sensation at higher frequencies. The describing function model is extended by the proposal of a nonlinear cue conflict model, in which cue weighting depends on the level of agreement between visual and vestibular cues.

  17. Proof-of-Concept Demonstration Results for Robotic Visual Servo Controllers

    Energy Technology Data Exchange (ETDEWEB)

    Chawda, P.V.

    2004-09-22

    There is significant motivation to provide robotic systems with improved autonomy as a means to significantly accelerate deactivation and decommissioning operations while also reducing the associated costs, removing human operators from hazardous environments, and reducing the required burden and skill of human operators. To achieve improved autonomy, fundamental research is focused on the challenges of developing visual servo controllers. The challenge in developing these controllers is that a camera provides 2-dimensional image information about the 3-dimensional Euclidean-space through a perspective (range dependent) projection that can be corrupted by uncertainty in the camera calibration matrix. Disturbances in this relationship (i.e., corruption in the sensor information) propagate erroneous information to the feedback controller of the robot, leading to potentially unpredictable task execution. This technical manual describes 3 proof-of-concept demonstrations of visual servo controllers developed from fundamental research aimed at these challenges. Specifically, one section describes the implementation of a cooperative visual servo control scheme with a camera-in-hand and a fixed camera to track a moving target despite uncertainty in the camera calibration and the unknown constant distance from the camera to a target where the camera is mounted on the end-effector of a 6 degrees-of-freedom hydraulic robot manipulator. The next section describes the implementation of 2 homography-based visual servo tracking and regulation controllers for a mobile robot with a calibrated camera despite an unknown time-varying distance from the camera to a target.

  18. The Next Generation of Ground Operations Command and Control; Scripting in C Sharp and Visual Basic

    Science.gov (United States)

    Ritter, George; Pedoto, Ramon

    2010-01-01

    This slide presentation reviews the use of scripting languages in Ground Operations Command and Control. It describes the use of scripting languages in a historical context, the advantages and disadvantages of scripts. It describes the Enhanced and Redesigned Scripting (ERS) language, that was designed to combine the features of a scripting language and the graphical and IDE richness of a programming language with the utility of scripting languages. ERS uses the Microsoft Visual Studio programming environment and offers custom controls that enable an ERS developer to extend the Visual Basic and C sharp language interface with the Payload Operations Integration Center (POIC) telemetry and command system.

  19. Handwriting performance in the absence of visual control in writer's cramp patients: Initial observations

    OpenAIRE

    Losch Florian; Hummel Sibylla; Chakarov Vihren; Schulte-Mönting Jürgen; Kristeva Rumyana

    2006-01-01

    Abstract Background The present study was aimed at investigating the writing parameters of writer's cramp patients and control subjects during handwriting of a test sentence in the absence of visual control. Methods Eight right-handed patients with writer's cramp and eight healthy volunteers as age-matched control subjects participated in the study. The experimental task consisted in writing a test sentence repeatedly for fifty times on a pressure-sensitive digital board. The subject did not ...

  20. The 4-D approach to visual control of autonomous systems

    Science.gov (United States)

    Dickmanns, Ernst D.

    1994-01-01

    Development of a 4-D approach to dynamic machine vision is described. Core elements of this method are spatio-temporal models oriented towards objects and laws of perspective projection in a foward mode. Integration of multi-sensory measurement data was achieved through spatio-temporal models as invariants for object recognition. Situation assessment and long term predictions were allowed through maintenance of a symbolic 4-D image of processes involving objects. Behavioral capabilities were easily realized by state feedback and feed-foward control.

  1. Top-Down Control of Visual Alpha Oscillations: Sources of Control Signals and Their Mechanisms of Action.

    Science.gov (United States)

    Wang, Chao; Rajagovindan, Rajasimhan; Han, Sahng-Min; Ding, Mingzhou

    2016-01-01

    Alpha oscillations (8-12 Hz) are thought to inversely correlate with cortical excitability. Goal-oriented modulation of alpha has been studied extensively. In visual spatial attention, alpha over the region of visual cortex corresponding to the attended location decreases, signifying increased excitability to facilitate the processing of impending stimuli. In contrast, in retention of verbal working memory, alpha over visual cortex increases, signifying decreased excitability to gate out stimulus input to protect the information held online from sensory interference. According to the prevailing model, this goal-oriented biasing of sensory cortex is effected by top-down control signals from frontal and parietal cortices. The present study tests and substantiates this hypothesis by (a) identifying the signals that mediate the top-down biasing influence, (b) examining whether the cortical areas issuing these signals are task-specific or task-independent, and (c) establishing the possible mechanism of the biasing action. High-density human EEG data were recorded in two experimental paradigms: a trial-by-trial cued visual spatial attention task and a modified Sternberg working memory task. Applying Granger causality to both sensor-level and source-level data we report the following findings. In covert visual spatial attention, the regions exerting top-down control over visual activity are lateralized to the right hemisphere, with the dipoles located at the right frontal eye field (FEF) and the right inferior frontal gyrus (IFG) being the main sources of top-down influences. During retention of verbal working memory, the regions exerting top-down control over visual activity are lateralized to the left hemisphere, with the dipoles located at the left middle frontal gyrus (MFG) being the main source of top-down influences. In both experiments, top-down influences are mediated by alpha oscillations, and the biasing effect is likely achieved via an inhibition

  2. Top-down Control of Visual Alpha Oscillations: Sources of Control Signals and Their Mechanisms of Action

    Directory of Open Access Journals (Sweden)

    Chao eWang

    2016-01-01

    Full Text Available Alpha oscillations (8 to 12 Hz are thought to inversely correlate with cortical excitability. Goal-oriented modulation of alpha has been studied extensively. In visual spatial attention, alpha over the region of visual cortex corresponding to the attended location decreases, signifying increased excitability to facilitate the processing of impending stimuli. In contrast, in retention of verbal working memory, alpha over visual cortex increases, signifying decreased excitability to gate out stimulus input to protect the information held online from sensory interference. According to the prevailing model, this goal-oriented biasing of sensory cortex is effected by top-down control signals from frontal and parietal cortices. The present study tests and substantiates this hypothesis by (a identifying the signals that mediate the top-down biasing influence, (b examining whether the cortical areas issuing these signals are task-specific or task-independent, and (c establishing the possible mechanism of the biasing action. High-density human EEG data were recorded in two experimental paradigms: a trial-by-trial cued visual spatial attention task and a modified Sternberg working memory task. Applying Granger causality to both sensor-level and source-level data we report the following findings. In covert visual spatial attention, the regions exerting top-down control over visual activity are lateralized to the right hemisphere, with the dipoles located at the right frontal eye field (FEF and the right inferior frontal gyrus (IFG being the main sources of top-down influences. During retention of verbal working memory, the regions exerting top-down control over visual activity are lateralized to the left hemisphere, with the dipoles located at the left middle frontal gyrus (MFG being the main source of top-down influences. In both experiments, top-down influences are mediated by alpha oscillations, and the biasing effect is likely achieved via an

  3. Relationship between reaction time, fine motor control, and visual-spatial perception on vigilance and visual-motor tasks in 22q11.2 Deletion Syndrome.

    LENUS (Irish Health Repository)

    Howley, Sarah A

    2012-10-15

    22q11.2 Deletion Syndrome (22q11DS) is a common microdeletion disorder associated with mild to moderate intellectual disability and specific neurocognitive deficits, particularly in visual-motor and attentional abilities. Currently there is evidence that the visual-motor profile of 22q11DS is not entirely mediated by intellectual disability and that these individuals have specific deficits in visual-motor integration. However, the extent to which attentional deficits, such as vigilance, influence impairments on visual motor tasks in 22q11DS is unclear. This study examines visual-motor abilities and reaction time using a range of standardised tests in 35 children with 22q11DS, 26 age-matched typically developing (TD) sibling controls and 17 low-IQ community controls. Statistically significant deficits were observed in the 22q11DS group compared to both low-IQ and TD control groups on a timed fine motor control and accuracy task. The 22q11DS group performed significantly better than the low-IQ control group on an untimed drawing task and were equivalent to the TD control group on point accuracy and simple reaction time tests. Results suggest that visual motor deficits in 22q11DS are primarily attributable to deficits in psychomotor speed which becomes apparent when tasks are timed versus untimed. Moreover, the integration of visual and motor information may be intact and, indeed, represent a relative strength in 22q11DS when there are no time constraints imposed. While this may have significant implications for cognitive remediation strategies for children with 22q11DS, the relationship between reaction time, visual reasoning, cognitive complexity, fine motor speed and accuracy, and graphomotor ability on visual-motor tasks is still unclear.

  4. Controllable single photon stimulation of retinal rod cells

    CERN Document Server

    Phan, Nam Mai; Bessarab, Dmitri A; Krivitsky, Leonid A

    2013-01-01

    Retinal rod cells are commonly assumed to be sensitive to single photons [1, 2, 3]. Light sources used in prior experiments exhibit unavoidable fluctuations in the number of emitted photons [4]. This leaves doubt about the exact number of photons used to stimulate the rod cell. In this letter, we interface rod cells of Xenopus laevis with a light source based on Spontaneous Parametric Down Conversion (SPDC) [5], which provides one photon at a time. Precise control of generation of single photons and directional delivery enables us to provide unambiguous proof of single photon sensitivity of rod cells without relying on the statistical assumptions. Quantum correlations between single photons in the SPDC enable us to determine quantum efficiency of the rod cell without pre-calibrated reference detectors [6, 7, 8]. These results provide the path for exploiting resources offered by quantum optics in generation and manipulation of light in visual studies. From a more general perspective, this method offers the ult...

  5. A dedicated circuit linking direction selective retinal ganglion cells to primary visual cortex

    OpenAIRE

    Cruz-Martín, Alberto; El-Danaf, Rana N.; Osakada, Fumitaka; Sriram, Balaji; Dhande, Onkar S.; Nguyen, Phong L.; Callaway, Edward M.; Ghosh, Anirvan; Huberman, Andrew D.

    2014-01-01

    How specific features in the environment are represented within the brain is an important unanswered question in neuroscience. A subset of retinal neurons, called direction selective ganglion cells (DSGCs) are specialized for detecting motion along specific axes of the visual field 1 . Despite extensive study of the retinal circuitry that endows DSGCs with their unique tuning properties 2,3 , their downstream circuitry in the brain and thus their contribution to visual processing has remained...

  6. Visualization of multivalent histone modification in a single cell reveals highly concerted epigenetic changes on differentiation of embryonic stem cells

    DEFF Research Database (Denmark)

    Hattori, Naoko; Niwa, Tohru; Kimura, Kana;

    2013-01-01

    Combinations of histone modifications have significant biological roles, such as maintenance of pluripotency and cancer development, but cannot be analyzed at the single cell level. Here, we visualized a combination of histone modifications by applying the in situ proximity ligation assay, which....... Bivalent modification was clearly visualized by iChmo in wild-type embryonic stem cells (ESCs) known to have it, whereas rarely in Suz12 knockout ESCs and mouse embryonic fibroblasts known to have little of it. iChmo was applied to analysis of epigenetic and phenotypic changes of heterogeneous cell...

  7. Visual inspections of N Reactor horizontal control rod channels

    International Nuclear Information System (INIS)

    Safety surveillance is performed in horizontal control rod (HCR) channels to locate conditions which could slow or block rod travel. The findings guide the application of preventive measures to assure eventual rod motion impairment will not occur. Borescopes and, more recently, miniaturized closed circuit television (CCTV) cameras have been used for these examinations. Inspections and measurement results are documented in annual surveillance reports, however reported CCTV observations have been limited to highlights. The objective of this report is to catalogue the CCTV recordings in a format suitable for analysis and interpretation and to ease the access to any desired location by noting tape counter readings corresponding with each tube block in view. Searching file tapes for conditions in a specific areas in the past required counting blocks as they passed the camera to determine the distance from a feature like the edge of the reflector or a steam vent gap. This report adds the observations from recent rod channel inspections (1987 and 1988) to a comprehensive survey of graphite conditions in the moderator and reflector regions of the N Reactor core. When completed, the stand-by status of graphite components will be available for use in restart or decommissioning deliberations

  8. Fuzzy logic control for selective hydrogenation of acetylene in ethylene rich streams using visual basic

    International Nuclear Information System (INIS)

    Presence of acetylene is technically disadvantageous in the ethylene rich gas streams from steam crackers. Acetylene tends to polymerize and inactivates the transition metal catalysts, forming highly explosive compounds. The acetylene content has to be selectively reduced to less than one part per million for such streams. The acetylene hydrogenation unit requires stringent control parameters and needs specialized process control techniques for its operation. This study is concerned with application of Fuzzy Logic Control to manipulate and control the process plant with higher precision and greater simplicity. The control program has been written in visual Basic and entails all major scenarios of work modes for successful hydrogenation of Acetylene. (author)

  9. Instrument Display Visual Angles for Conventional Aircraft and the MQ-9 Ground Control Station

    Science.gov (United States)

    Bendrick, Gregg A.; Kamine, Tovy Haber

    2008-01-01

    Aircraft instrument panels should be designed such that primary displays are in optimal viewing location to minimize pilot perception and response time. Human Factors engineers define three zones (i.e. "cones") of visual location: 1) "Easy Eye Movement" (foveal vision); 2) "Maximum Eye Movement" (peripheral vision with saccades), and 3) "Head Movement" (head movement required). Instrument display visual angles were measured to determine how well conventional aircraft (T-34, T-38, F- 15B, F-16XL, F/A-18A, U-2D, ER-2, King Air, G-III, B-52H, DC-10, B747-SCA) and the MQ-9 ground control station (GCS) complied with these standards, and how they compared with each other. Methods: Selected instrument parameters included: attitude, pitch, bank, power, airspeed, altitude, vertical speed, heading, turn rate, slip/skid, AOA, flight path, latitude, longitude, course, bearing, range and time. Vertical and horizontal visual angles for each component were measured from the pilot s eye position in each system. Results: The vertical visual angles of displays in conventional aircraft lay within the cone of "Easy Eye Movement" for all but three of the parameters measured, and almost all of the horizontal visual angles fell within this range. All conventional vertical and horizontal visual angles lay within the cone of "Maximum Eye Movement". However, most instrument vertical visual angles of the MQ-9 GCS lay outside the cone of "Easy Eye Movement", though all were within the cone of "Maximum Eye Movement". All the horizontal visual angles for the MQ-9 GCS were within the cone of "Easy Eye Movement". Discussion: Most instrument displays in conventional aircraft lay within the cone of "Easy Eye Movement", though mission-critical instruments sometimes displaced less important instruments outside this area. Many of the MQ-9 GCS systems lay outside this area. Specific training for MQ-9 pilots may be needed to avoid increased response time and potential error during flight.

  10. 3D-dynamic visualization of complex molecular cell biology processes : 1-year university students' understanding of visualizations of signal transduction

    OpenAIRE

    Jacobsson, Johan Lars Henrik

    2008-01-01

    This study deals with the use of 3D-dynamic visualizations for teaching complex molecular cell biology concepts. The focus is on signal transduction, which is a concept that constitutes an important part of biological systems. 3D-dynamic visualizations (animations) were produced and shown for a total of 24 students attending a course in molecular cell biology at Karlstad University, Sweden. Data were collected by questionnaires and interviews which were structured around the understandability...

  11. Gaze Behavior in Basketball Shooting: Further Evidence for Online Visual Control

    Science.gov (United States)

    de Oliveira, Rita F.; Oudejans, Raoul R. D.; Beek, Peter J.

    2008-01-01

    The aim of the present study was to help resolve conflicting findings and interpretations regarding the visual control of basketball shooting by examining the looking behavior of 6 expert basketball players (3 with a low shooting style and 3 with a high shooting style) executing both free throws and jump shots. Based on previous findings, they…

  12. A fast and flexible one-dimensional image processing implementation for visual feedback control

    Science.gov (United States)

    Richardson, Richard W.; Penix, Wayne A.; Richardson, Russell D.

    1988-01-01

    A simple and efficient image processing system is described which can provide one-dimensional image processing for sample rates approaching video rates. The system is utilized for visual feedback where guidance and process controls are required, such as for arc-welding robots.

  13. IMAGE-BASED VISUAL SERVOING FOR ROBOTIC SYSTEMS: A NONLINEAR LYAPUNOV-BASED CONTROL APPROACH

    Science.gov (United States)

    The objective of this project is to enable current and future EM robots with an increased ability to perceive and interact with unstructured and unknown environments through the use of camera-based visual servo controlled robots. The scientific goals of this research are to devel...

  14. Acute Caffeine Consumption Enhances the Executive Control of Visual Attention in Habitual Consumers

    Science.gov (United States)

    Brunye, Tad T.; Mahoney, Caroline R.; Lieberman, Harris R.; Giles, Grace E.; Taylor, Holly A.

    2010-01-01

    Recent work suggests that a dose of 200-400mg caffeine can enhance both vigilance and the executive control of visual attention in individuals with low caffeine consumption profiles. The present study seeks to determine whether individuals with relatively high caffeine consumption profiles would show similar advantages. To this end, we examined…

  15. Self-Esteem, Locus of Control and Various Aspects of Psychopathology of Adults with Visual Impairments

    Science.gov (United States)

    Papadopoulos, Konstantinos; Paralikas, Theodosis; Barouti, Marialena; Chronopoulou, Elena

    2014-01-01

    The exploratory study presented in this article looks into the possible differences in psychosocial aspects (self-esteem and locus of control) and aspects of psychopathology (depression, anxiety, melancholia, asthenia, and mania) amongst sighted adults and adults with visual impairments. Moreover, the study aims to examine the possible…

  16. Manual control of yaw motion with combined visual and vestibular cues

    Science.gov (United States)

    Zacharias, G. L.; Young, L. R.

    1977-01-01

    Measurements are made of manual control performance in the closed-loop task of nulling perceived self-rotation velocity about an earth-vertical axis. Self-velocity estimation was modelled as a function of the simultaneous presentation of vestibular and peripheral visual field motion cues. Based on measured low-frequency operator behavior in three visual field environments, a parallel channel linear model is proposed which has separate visual and vestibular pathways summing in a complementary manner. A correction to the frequency responses is provided by a separate measurement of manual control performance in an analogous visual pursuit nulling task. The resulting dual-input describing function for motion perception dependence on combined cue presentation supports the complementary model, in which vestibular cues dominate sensation at frequencies above 0.05 Hz. The describing function model is extended by the proposal of a non-linear cue conflict model, in which cue weighting depends on the level of agreement between visual and vestibular cues.

  17. Generation of Rho Zero Cells: Visualization and Quantification of the mtDNA Depletion Process

    OpenAIRE

    Susanna Schubert; Sandra Heller; Birgit Löffler; Ingo Schäfer; Martina Seibel; Gaetano Villani; Peter Seibel

    2015-01-01

    Human mitochondrial DNA (mtDNA) is located in discrete DNA-protein complexes, so called nucleoids. These structures can be easily visualized in living cells by utilizing the fluorescent stain PicoGreen®. In contrary, cells devoid of endogenous mitochondrial genomes (ρ0 cells) display no mitochondrial staining in the cytoplasm. A modified restriction enzyme can be targeted to mitochondria to cleave the mtDNA molecules in more than two fragments, thereby activating endogenous nucleases. By a...

  18. cellPACK: A Virtual Mesoscope to Model and Visualize Structural Systems Biology

    OpenAIRE

    Johnson, Graham T; Autin, Ludovic; Al-Alusi, Mostafa; Goodsell, David S.; Sanner, Michel F.; Olson, Arthur J.

    2014-01-01

    cellPACK assembles computational models of the biological mesoscale, an intermediate scale (10−7–10−8m) between molecular and cellular biology. cellPACK’s modular architecture unites existing and novel packing algorithms to generate, visualize and analyze comprehensive 3D models of complex biological environments that integrate data from multiple experimental systems biology and structural biology sources. cellPACK is currently available as open source code, with tools for validation of model...

  19. Visualization of mRNA translation in living cells

    OpenAIRE

    RODRIGUEZ, ALEXIS J.; Shenoy, Shailesh M; Singer, Robert H.; Condeelis, John

    2006-01-01

    The role of mRNA localization is presumably to effect cell asymmetry by synthesizing proteins in specific cellular compartments. However, protein synthesis has never been directly demonstrated at the sites of mRNA localization. To address this, we developed a live cell method for imaging translation of β-actin mRNA. Constructs coding for β-actin, containing tetracysteine motifs, were transfected into C2C12 cells, and sites of nascent polypeptide chains were detected using the biarsenial dyes ...

  20. Fuel cell with internal flow control

    Science.gov (United States)

    Haltiner, Jr., Karl J.; Venkiteswaran, Arun

    2012-06-12

    A fuel cell stack is provided with a plurality of fuel cell cassettes where each fuel cell cassette has a fuel cell with an anode and cathode. The fuel cell stack includes an anode supply chimney for supplying fuel to the anode of each fuel cell cassette, an anode return chimney for removing anode exhaust from the anode of each fuel cell cassette, a cathode supply chimney for supplying oxidant to the cathode of each fuel cell cassette, and a cathode return chimney for removing cathode exhaust from the cathode of each fuel cell cassette. A first fuel cell cassette includes a flow control member disposed between the anode supply chimney and the anode return chimney or between the cathode supply chimney and the cathode return chimney such that the flow control member provides a flow restriction different from at least one other fuel cell cassettes.

  1. Common transcriptional mechanisms for visual photoreceptor cell differentiation among Pancrustaceans.

    Directory of Open Access Journals (Sweden)

    Simpla Mahato

    2014-07-01

    Full Text Available A hallmark of visual rhabdomeric photoreceptors is the expression of a rhabdomeric opsin and uniquely associated phototransduction molecules, which are incorporated into a specialized expanded apical membrane, the rhabdomere. Given the extensive utilization of rhabdomeric photoreceptors in the eyes of protostomes, here we address whether a common transcriptional mechanism exists for the differentiation of rhabdomeric photoreceptors. In Drosophila, the transcription factors Pph13 and Orthodenticle (Otd direct both aspects of differentiation: rhabdomeric opsin transcription and rhabdomere morphogenesis. We demonstrate that the orthologs of both proteins are expressed in the visual systems of the distantly related arthropod species Tribolium castaneum and Daphnia magna and that their functional roles are similar in these species. In particular, we establish that the Pph13 homologs have the ability to bind a subset of Rhodopsin core sequence I sites and that these sites are present in key phototransduction genes of both Tribolium and Daphnia. Furthermore, Pph13 and Otd orthologs are capable of executing deeply conserved functions of photoreceptor differentiation as evidenced by the ability to rescue their respective Drosophila mutant phenotypes. Pph13 homologs are equivalent in their ability to direct both rhabdomere morphogenesis and opsin expression within Drosophila, whereas Otd paralogs demonstrate differential abilities to regulate photoreceptor differentiation. Finally, loss-of-function analyses in Tribolium confirm the conserved requirement of Pph13 and Otd in regulating both rhabdomeric opsin transcription and rhabdomere morphogenesis. Taken together, our data identify components of a regulatory framework for rhabdomeric photoreceptor differentiation in Pancrustaceans, providing a foundation for defining ancestral regulatory modules of rhabdomeric photoreceptor differentiation.

  2. Image-Based Visual Servoing for Robotic Systems: A Nonlinear Lyapunov-Based Control Approach

    International Nuclear Information System (INIS)

    There is significant motivation to provide robotic systems with improved autonomy as a means to significantly accelerate deactivation and decommissioning (DandD) operations while also reducing the associated costs, removing human operators from hazardous environments, and reducing the required burden and skill of human operators. To achieve improved autonomy, this project focused on the basic science challenges leading to the development of visual servo controllers. The challenge in developing these controllers is that a camera provides 2-dimensional image information about the 3-dimensional Euclidean-space through a perspective (range dependent) projection that can be corrupted by uncertainty in the camera calibration matrix and by disturbances such as nonlinear radial distortion. Disturbances in this relationship (i.e., corruption in the sensor information) propagate erroneous information to the feedback controller of the robot, leading to potentially unpredictable task execution. This research project focused on the development of a visual servo control methodology that targets compensating for disturbances in the camera model (i.e., camera calibration and the recovery of range information) as a means to achieve predictable response by the robotic system operating in unstructured environments. The fundamental idea is to use nonlinear Lyapunov-based techniques along with photogrammetry methods to overcome the complex control issues and alleviate many of the restrictive assumptions that impact current robotic applications. The outcome of this control methodology is a plug-and-play visual servoing control module that can be utilized in conjunction with current technology such as feature recognition and extraction to enable robotic systems with the capabilities of increased accuracy, autonomy, and robustness, with a larger field of view (and hence a larger workspace). The developed methodology has been reported in numerous peer-reviewed publications and the

  3. Pipeline tracking for fully-actuated autonomous underwater vehicle using visual servo control

    OpenAIRE

    Krupinsky, Szymon; Allibert, Guillaume; Hua, Minh Duc; Hamel, Tarek

    2012-01-01

    International audience This paper describes a nonlinear image-based visual servo control algorithm for the pipeline tracking problem of a fully-actuated underwater vehicle. The dynamic model of a generic autonomous underwater vehicle (AUV), incorporating all significant forces and torques is developed and a generic velocity control strategy is proposed. The desired velocities in the plane orthogonal to the direction of the pipeline along with the yaw velocity are derived from the image seq...

  4. A Graphical Representation Framework for Enhanced Visualization of Construction Control Processes

    OpenAIRE

    Hays, Benjamin James

    2002-01-01

    Graphical representation for construction control information--processes such as scheduling, budgeting and RFIs--follows no formalized method. Many graphics neglect relevant information necessary to highlight trends in or relationships between processes. The principles of data graphics offer visual capabilities beyond those currently employed by the construction industry to display appropriate information in a manner that enhances comprehension of control processes. This paper describes a ...

  5. Audio-visual feedback improves the BCI performance in the navigational control of a humanoid robot.

    Science.gov (United States)

    Tidoni, Emmanuele; Gergondet, Pierre; Kheddar, Abderrahmane; Aglioti, Salvatore M

    2014-01-01

    Advancement in brain computer interfaces (BCI) technology allows people to actively interact in the world through surrogates. Controlling real humanoid robots using BCI as intuitively as we control our body represents a challenge for current research in robotics and neuroscience. In order to successfully interact with the environment the brain integrates multiple sensory cues to form a coherent representation of the world. Cognitive neuroscience studies demonstrate that multisensory integration may imply a gain with respect to a single modality and ultimately improve the overall sensorimotor performance. For example, reactivity to simultaneous visual and auditory stimuli may be higher than to the sum of the same stimuli delivered in isolation or in temporal sequence. Yet, knowledge about whether audio-visual integration may improve the control of a surrogate is meager. To explore this issue, we provided human footstep sounds as audio feedback to BCI users while controlling a humanoid robot. Participants were asked to steer their robot surrogate and perform a pick-and-place task through BCI-SSVEPs. We found that audio-visual synchrony between footsteps sound and actual humanoid's walk reduces the time required for steering the robot. Thus, auditory feedback congruent with the humanoid actions may improve motor decisions of the BCI's user and help in the feeling of control over it. Our results shed light on the possibility to increase robot's control through the combination of multisensory feedback to a BCI user. PMID:24987350

  6. Handwriting performance in the absence of visual control in writer's cramp patients: Initial observations

    Directory of Open Access Journals (Sweden)

    Losch Florian

    2006-04-01

    Full Text Available Abstract Background The present study was aimed at investigating the writing parameters of writer's cramp patients and control subjects during handwriting of a test sentence in the absence of visual control. Methods Eight right-handed patients with writer's cramp and eight healthy volunteers as age-matched control subjects participated in the study. The experimental task consisted in writing a test sentence repeatedly for fifty times on a pressure-sensitive digital board. The subject did not have visual control on his handwriting. The writing performance was stored on a PC and analyzed off-line. Results During handwriting all patients developed a typical dystonic limb posture and reported an increase in muscular tension along the experimental session. The patients were significantly slower than the controls, with lower mean vertical pressure of the pen tip on the paper and they could not reach the endmost letter of the sentence in the given time window. No other handwriting parameter differences were found between the two groups. Conclusion Our findings indicate that during writing in the absence of visual feedback writer's cramp patients are slower and could not reach the endmost letter of the test sentence, but their level of automatization is not impaired and writer's cramp handwriting parameters are similar to those of the controls except for even lower vertical pressure of the pen tip on the paper, which is probably due to a changed strategy in such experimental conditions.

  7. Attention and response control in ADHD. Evaluation through integrated visual and auditory continuous performance test.

    Science.gov (United States)

    Moreno-García, Inmaculada; Delgado-Pardo, Gracia; Roldán-Blasco, Carmen

    2015-01-01

    This study assesses attention and response control through visual and auditory stimuli in a primary care pediatric sample. The sample consisted of 191 participants aged between 7 and 13 years old. It was divided into 2 groups: (a) 90 children with ADHD, according to diagnostic (DSM-IV-TR) (APA, 2002) and clinical (ADHD Rating Scale-IV) (DuPaul, Power, Anastopoulos, & Reid, 1998) criteria, and (b) 101 children without a history of ADHD. The aims were: (a) to determine and compare the performance of both groups in attention and response control, (b) to identify attention and response control deficits in the ADHD group. Assessments were carried out using the Integrated Visual and Auditory Continuous Performance Test (IVA/CPT, Sandford & Turner, 2002). Results showed that the ADHD group had visual and auditory attention deficits, F(3, 170) = 14.38; p ADHD showed inattention, mental processing speed deficits, and loss of concentration with visual stimuli. Both groups yielded a better performance in attention with auditory stimuli. PMID:25734571

  8. A Model of Generating Visual Place Cells Based on Environment Perception and Similar Measure

    Science.gov (United States)

    2016-01-01

    It is an important content to generate visual place cells (VPCs) in the field of bioinspired navigation. By analyzing the firing characteristic of biological place cells and the existing methods for generating VPCs, a model of generating visual place cells based on environment perception and similar measure is abstracted in this paper. VPCs' generation process is divided into three phases, including environment perception, similar measure, and recruiting of a new place cell. According to this process, a specific method for generating VPCs is presented. External reference landmarks are obtained based on local invariant characteristics of image and a similar measure function is designed based on Euclidean distance and Gaussian function. Simulation validates the proposed method is available. The firing characteristic of the generated VPCs is similar to that of biological place cells, and VPCs' firing fields can be adjusted flexibly by changing the adjustment factor of firing field (AFFF) and firing rate's threshold (FRT). PMID:27597859

  9. A Model of Generating Visual Place Cells Based on Environment Perception and Similar Measure.

    Science.gov (United States)

    Zhou, Yang; Wu, Dewei

    2016-01-01

    It is an important content to generate visual place cells (VPCs) in the field of bioinspired navigation. By analyzing the firing characteristic of biological place cells and the existing methods for generating VPCs, a model of generating visual place cells based on environment perception and similar measure is abstracted in this paper. VPCs' generation process is divided into three phases, including environment perception, similar measure, and recruiting of a new place cell. According to this process, a specific method for generating VPCs is presented. External reference landmarks are obtained based on local invariant characteristics of image and a similar measure function is designed based on Euclidean distance and Gaussian function. Simulation validates the proposed method is available. The firing characteristic of the generated VPCs is similar to that of biological place cells, and VPCs' firing fields can be adjusted flexibly by changing the adjustment factor of firing field (AFFF) and firing rate's threshold (FRT). PMID:27597859

  10. Lighting energy savings potential of split-pane electrochromic windows controlled for daylighting with visual comfort

    Energy Technology Data Exchange (ETDEWEB)

    Software, Anyhere; Fernandes, Luis; Lee, Eleanor; Ward, Greg

    2013-03-15

    A simulation study was conducted to evaluate lighting energy savings of split-pane electrochromic (EC) windows controlled to satisfy key visual comfort parameters. Using the Radiance lighting simulation software, interior illuminance and luminance levels were computed for a south-facing private office illuminated by a window split into two independently-controlled EC panes. The transmittance of these was optimized hourly for a workplane illuminance target while meeting visual comfort constraints, using a least-squares algorithm with linear inequality constraints. Blinds were successively deployed until visual comfort criteria were satisfied. The energy performance of electrochromics proved to be highly dependent on how blinds were controlled. With hourly blind position adjustments, electrochromics showed significantly higher (62percent and 53percent, respectively without and with overhang) lighting energy consumption than clear glass. With a control algorithm designed to better approximate realistic manual control by an occupant, electrochromics achieved significant savings (48percent and 37percent, respectively without and with overhang). In all cases, energy consumption decreased when the workplace illuminance target was increased. In addition, the fraction of time during which the occupant had an unobstructed view of the outside was significantly greater with electrochromics: 10 months out of the year versus a handful of days for the reference case.

  11. Image-Based Visual Servoing for Robotic Systems: A Nonlinear Lyapunov-Based Control Approach

    International Nuclear Information System (INIS)

    The objective of this project is to enable current and future EM robots with an increased ability to perceive and interact with unstructured and unknown environments through the use of camera-based visual servo controlled robots. The scientific goals of this research are to develop a new visual servo control methodology that: (1) adapts for the unknown camera calibration parameters (e.g., focal length, scaling factors, camera position and orientation) and the physical parameters of the robotic system (e.g., mass, inertia, friction), (2) compensates for unknown depth information (extract 3D information from the 2D image), and (3) enables multi-uncalibrated cameras to be used as a means to provide a larger field-of-view. Nonlinear Lyapunov-based techniques are being used to overcome the complex control issues and alleviate many of the restrictive assumptions that impact current visual servo controlled robotic systems. The potential relevance of this control methodology will be a plug-and-play visual servoing control module that can be utilized in conjunction with current technology such as feature extraction and recognition, to enable current EM robotic systems with the capabilities of increased accuracy, autonomy, and robustness, with a larger field of view (and hence a larger workspace). These capabilities will enable EM robots to significantly accelerate D and D operations by providing for improved robot autonomy and increased worker productivity, while also reducing the associated costs, removing the human operator from the hazardous environments, and reducing the burden and skill of the human operators

  12. Xenopus laevis retinal ganglion cell dendritic arbors develop independently of visual stimulation

    Directory of Open Access Journals (Sweden)

    Rebecca L. Rigel

    2004-06-01

    Full Text Available Newly formed neurons must locate their appropriate target cells and then form synaptic connections with these targets in order to establish a functional nervous system. In the vertebrate retina, retinal ganglion cell (RGC dendrites extend from the cell body and form synapses with nearby amacrine and bipolar cells. RGC axons, however, exit the retina and synapse with the dendrites of midbrain neurons in the optic tectum. We examined how visual stimulation influenced Xenopus RGC dendritic arborization. Neuronal activity is known to be an important factor in shaping dendritic and axonal arborization. Thus, we reared tadpoles in dark and light environments then used rhodamine dextran retrograde labeling to identify RGCs in the retina. When we compared RGC dendritic arbors from tadpoles reared in dark and light environments, we found no morphological differences, suggesting that physiological visual activity did not contribute to the morphological development of Xenopus RGC dendritic arbors.

  13. Xenopus laevis Retinal Ganglion Cell Dendritic Arbors Develop Independently of Visual Stimulation

    Directory of Open Access Journals (Sweden)

    Barbara Lom

    2004-01-01

    Full Text Available Newly formed neurons must locate their appropriate target cells and then form synaptic connections with these targets in order to establish a functional nervous system. In the vertebrate retina, retinal ganglion cell (RGC dendrites extend from the cell body and form synapses with nearby amacrine and bipolar cells. RGC axons, however, exit the retina and synapse with the dendrites of midbrain neurons in the optic tectum. We examined how visual stimulation influenced Xenopus RGC dendritic arborization. Neuronal activity is known to be an important factor in shaping dendritic and axonal arborization. Thus, we reared tadpoles in dark and light environments then used rhodamine dextran retrograde labeling to identify RGCs in the retina. When we compared RGC dendritic arbors from tadpoles reared in dark and light environments, we found no morphological differences, suggesting that physiological visual activity did not contribute to the morphological development of Xenopus RGC dendritic arbors.

  14. Visual servo walking control for humanoids with finite-time convergence and smooth robot velocities

    Science.gov (United States)

    Delfin, Josafat; Becerra, Hector M.; Arechavaleta, Gustavo

    2016-07-01

    In this paper, we address the problem of humanoid locomotion guided from information of a monocular camera. The goal of the robot is to reach a desired location defined in terms of a target image, i.e., a positioning task. The proposed approach allows us to introduce a desired time to complete the positioning task, which is advantageous in contrast to the classical exponential convergence. In particular, finite-time convergence is achieved while generating smooth robot velocities and considering the omnidirectional waking capability of the robot. In addition, we propose a hierarchical task-based control scheme, which can simultaneously handle the visual positioning and the obstacle avoidance tasks without affecting the desired time of convergence. The controller is able to activate or inactivate the obstacle avoidance task without generating discontinuous velocity references while the humanoid is walking. Stability of the closed loop for the two task-based control is demonstrated theoretically even during the transitions between the tasks. The proposed approach is generic in the sense that different visual control schemes are supported. We evaluate a homography-based visual servoing for position-based and image-based modalities, as well as for eye-in-hand and eye-to-hand configurations. The experimental evaluation is performed with the humanoid robot NAO.

  15. Cdc42-mediated tubulogenesis controls cell specification

    DEFF Research Database (Denmark)

    Kesavan, Gokul; Sand, Fredrik Wolfhagen; Greiner, Thomas Uwe;

    2009-01-01

    Understanding how cells polarize and coordinate tubulogenesis during organ formation is a central question in biology. Tubulogenesis often coincides with cell-lineage specification during organ development. Hence, an elementary question is whether these two processes are independently controlled...... later for maintaining apical cell polarity. Finally, we show that Cdc42 controls cell specification non-cell-autonomously by providing the correct microenvironment for proper control of cell-fate choices of multipotent progenitors. For a video summary of this article, see the PaperFlick file with the......, or whether proper cell specification depends on formation of tubes. To address these fundamental questions, we have studied the functional role of Cdc42 in pancreatic tubulogenesis. We present evidence that Cdc42 is essential for tube formation, specifically for initiating microlumen formation and...

  16. Drivers' Visual Behavior When Using Hand-Held and Hands-Free Cell Phones

    OpenAIRE

    Fitch, Gregory M.; Guo, Feng; Hanowski, Richard J.; Perez, M. P.

    2014-01-01

    This study investigated driver distraction and how the use of handheld (HH), portable hands-free (PHF), and integrated hands-free (IHF) cell phones affected the visual behavior of motor vehicle drivers. Method A naturalistic driving study recorded 204 participating drivers using video cameras and vehicle sensors for an average of 31 days. A total of 1564 cell phone calls made and 844 text messages sent while driving were sampled and underwent a video review. Baselines were established by reco...

  17. Teneurin-3 Specifies Morphological and Functional Connectivity of Retinal Ganglion Cells in the Vertebrate Visual System

    OpenAIRE

    Paride Antinucci; Nikolas Nikolaou; Martin P. Meyer; Robert Hindges

    2013-01-01

    Summary A striking feature of the CNS is the precise wiring of its neuronal connections. During vertebrate visual system development, different subtypes of retinal ganglion cells (RGCs) form specific connections with their corresponding synaptic partners. However, the underlying molecular mechanisms remain to be fully elucidated. Here, we report that the cell-adhesive transmembrane protein Teneurin-3 (Tenm3) is required by zebrafish RGCs for acquisition of their correct morphological and func...

  18. NaviCell Web Service for network-based data visualization.

    Science.gov (United States)

    Bonnet, Eric; Viara, Eric; Kuperstein, Inna; Calzone, Laurence; Cohen, David P A; Barillot, Emmanuel; Zinovyev, Andrei

    2015-07-01

    Data visualization is an essential element of biological research, required for obtaining insights and formulating new hypotheses on mechanisms of health and disease. NaviCell Web Service is a tool for network-based visualization of 'omics' data which implements several data visual representation methods and utilities for combining them together. NaviCell Web Service uses Google Maps and semantic zooming to browse large biological network maps, represented in various formats, together with different types of the molecular data mapped on top of them. For achieving this, the tool provides standard heatmaps, barplots and glyphs as well as the novel map staining technique for grasping large-scale trends in numerical values (such as whole transcriptome) projected onto a pathway map. The web service provides a server mode, which allows automating visualization tasks and retrieving data from maps via RESTful (standard HTTP) calls. Bindings to different programming languages are provided (Python and R). We illustrate the purpose of the tool with several case studies using pathway maps created by different research groups, in which data visualization provides new insights into molecular mechanisms involved in systemic diseases such as cancer and neurodegenerative diseases. PMID:25958393

  19. The Next Generation of Ground Operations Command and Control; Scripting in C no. and Visual Basic

    Science.gov (United States)

    Ritter, George; Pedoto, Ramon

    2010-01-01

    Scripting languages have become a common method for implementing command and control solutions in space ground operations. The Systems Test and Operations Language (STOL), the Huntsville Operations Support Center (HOSC) Scripting Language Processor (SLP), and the Spacecraft Control Language (SCL) offer script-commands that wrap tedious operations tasks into single calls. Since script-commands are interpreted, they also offer a certain amount of hands-on control that is highly valued in space ground operations. Although compiled programs seem to be unsuited for interactive user control and are more complex to develop, Marshall Space flight Center (MSFC) has developed a product called the Enhanced and Redesign Scripting (ERS) that makes use of the graphical and logical richness of a programming language while offering the hands-on and ease of control of a scripting language. ERS is currently used by the International Space Station (ISS) Payload Operations Integration Center (POIC) Cadre team members. ERS integrates spacecraft command mnemonics, telemetry measurements, and command and telemetry control procedures into a standard programming language, while making use of Microsoft's Visual Studio for developing Visual Basic (VB) or C# ground operations procedures. ERS also allows for script-style user control during procedure execution using a robust graphical user input and output feature. The availability of VB and C# programmers, and the richness of the languages and their development environment, has allowed ERS to lower our "script" development time and maintenance costs at the Marshall POIC.

  20. Development of a visual control and display system for the SMART plant analyzer

    International Nuclear Information System (INIS)

    A Visual Control and Display System (VCDS) for the SMART plant analyzer has been developed using the MMS simulation tools. The SAMRT plant analyzer consists of the VCDS and the MMS SMART model. The MMS SMART model is a numerical simulation model for the SMART plant and is composed of the MMS real-time modules and control blocks. It covers the whole plant including primary, secondary and auxiliary systems. The developed VCDS is Graphical User Interfaces (GUI) that is running in a synchronized way with the SMART model. The VCDS consists of the MMS Simulation tools and seven control and display screens. The VCDS provides easy means for the control and display of the SMART model status. The VCDS allows users to display and change a specified list of model variables and transient scenarios interactively through the MMS simulation tools. The control and display screens are developed with Visual Basic 6.0 and MMI32 ActiveX controls and it can be executed in several TCP/IP networked computers simultaneously. The developed VCDS can be utilized for the engineering simulation of the SMART plant operation, and for control logic and operational procedure developments

  1. Line Tracking Control of a Two-Wheeled Mobile Robot Using Visual Feedback

    Directory of Open Access Journals (Sweden)

    G. H. Lee

    2013-03-01

    Full Text Available This article presents the development and control of a two‐wheeled mobile robot as the base of a human carrier for an amusement/transportation vehicle. The robot has a combined structure of two systems: a line tracking mobile robot and an inverted pendulum system that maintains balance while following a line on the floor. The mobile robot is purposely designed to carry a human operator or humanoid arms. The robot has the capability to follow the line on the floor using visual feedback, as well as maintaining its balance on two wheels. A visual servoing technique allows the robot to follow the line on the floor captured by a camera as the desired trajectory. Controllers are designed to have good line tracking and balancing performance using sensor fusion techniques. Experimental studies involving the robot following a line demonstrate the feasibility of it being an amusement vehicle.

  2. A dedicated circuit links direction-selective retinal ganglion cells to the primary visual cortex

    Science.gov (United States)

    Cruz-Martín, Alberto; El-Danaf, Rana N.; Osakada, Fumitaka; Sriram, Balaji; Dhande, Onkar S.; Nguyen, Phong L.; Callaway, Edward M.; Ghosh, Anirvan; Huberman, Andrew D.

    2014-03-01

    How specific features in the environment are represented within the brain is an important unanswered question in neuroscience. A subset of retinal neurons, called direction-selective ganglion cells (DSGCs), are specialized for detecting motion along specific axes of the visual field. Despite extensive study of the retinal circuitry that endows DSGCs with their unique tuning properties, their downstream circuitry in the brain and thus their contribution to visual processing has remained unclear. In mice, several different types of DSGCs connect to the dorsal lateral geniculate nucleus (dLGN), the visual thalamic structure that harbours cortical relay neurons. Whether direction-selective information computed at the level of the retina is routed to cortical circuits and integrated with other visual channels, however, is unknown. Here we show that there is a di-synaptic circuit linking DSGCs with the superficial layers of the primary visual cortex (V1) by using viral trans-synaptic circuit mapping and functional imaging of visually driven calcium signals in thalamocortical axons. This circuit pools information from several types of DSGCs, converges in a specialized subdivision of the dLGN, and delivers direction-tuned and orientation-tuned signals to superficial V1. Notably, this circuit is anatomically segregated from the retino-geniculo-cortical pathway carrying non-direction-tuned visual information to deeper layers of V1, such as layer 4. Thus, the mouse harbours several functionally specialized, parallel retino-geniculo-cortical pathways, one of which originates with retinal DSGCs and delivers direction- and orientation-tuned information specifically to the superficial layers of the primary visual cortex. These data provide evidence that direction and orientation selectivity of some V1 neurons may be influenced by the activation of DSGCs.

  3. Engaging Direct Care Providers in Improving Infection Prevention and Control Practices Using Participatory Visual Methods.

    Science.gov (United States)

    Backman, Chantal; Bruce, Natalie; Marck, Patricia; Vanderloo, Saskia

    2016-01-01

    The purpose of this quality improvement project was to determine the feasibility of using provider-led participatory visual methods to scrutinize 4 hospital units' infection prevention and control practices. Methods included provider-led photo walkabouts, photo elicitation sessions, and postimprovement photo walkabouts. Nurses readily engaged in using the methods to examine and improve their units' practices and reorganize their work environment. PMID:26681499

  4. Volumetric Calibration of Stereo Camera in Visual Servo Based Robot Control

    OpenAIRE

    Ulises,; Sohyung,; Cho,, Myeong-Chan; Asfour,; Shihab; Perez, De

    2009-01-01

    The primary objective of the paper is to propose a calibration method for a stereo camera used in a visual servo control for a robot manipulator. Specifically, projection matrix between the stereo camera and world coordinates is established using few calibration points and solved using the single value decomposition technique. Then calibration accuracy is compared for a randomized and designed set of points, and economical number of calibration points is recommended. Additionally, the non-lin...

  5. Progress in animation of an EMA-controlled tongue model for acoustic-visual speech synthesis

    CERN Document Server

    Steiner, Ingmar

    2012-01-01

    We present a technique for the animation of a 3D kinematic tongue model, one component of the talking head of an acoustic-visual (AV) speech synthesizer. The skeletal animation approach is adapted to make use of a deformable rig controlled by tongue motion capture data obtained with electromagnetic articulography (EMA), while the tongue surface is extracted from volumetric magnetic resonance imaging (MRI) data. Initial results are shown and future work outlined.

  6. Timing and sequence of brain activity in top-down control of visual-spatial attention.

    OpenAIRE

    Tineke Grent-'t-Jong; Woldorff, Marty G.

    2007-01-01

    Recent brain imaging studies using functional magnetic resonance imaging (fMRI) have implicated a frontal-parietal network in the top-down control of attention. However, little is known about the timing and sequence of activations within this network. To investigate these timing questions, we used event-related electrical brain potentials (ERPs) and a specially designed visual-spatial attentional-cueing paradigm, which were applied as part of a multi-methodological approach that included a cl...

  7. Development of visual motion perception for prospective control: Brain and behavioural studies in infants

    OpenAIRE

    Seth B. Agyei; Ruud eVan der Weel; van der Meer, Audrey L. H.

    2016-01-01

    During infancy, smart perceptual mechanisms develop allowing infants to judge time-space motion dynamics more efficiently with age and locomotor experience. This emerging capacity may be vital to enable preparedness for upcoming events and to be able to navigate in a changing environment. Little is known about brain changes that support the development of prospective control and about processes, such as preterm birth, that may compromise it. As a function of perception of visual motion, this ...

  8. Do glial cells control pain?

    OpenAIRE

    Suter, Marc R; Wen, Yeong-Ray; Decosterd, Isabelle; Ji, Ru-Rong

    2007-01-01

    Management of chronic pain is a real challenge, and current treatments focusing on blocking neurotransmission in the pain pathway have only resulted in limited success. Activation of glia cells has been widely implicated in neuroinflammation in the central nervous system, leading to neruodegeneration in many disease conditions such as Alzheimer’s and multiple sclerosis. The inflammatory mediators released by activated glial cells, such as tumor necrosis factor-α and interleukin-1β can not onl...

  9. Control of Robotic Welding Cell

    OpenAIRE

    Zabukovec, Andraž

    2013-01-01

    Industrial robots are common place in most modern manufacturing plants because the people running these factories are interested in reducing the plants’ dependence on a human workforce and to simultaneously improve productivity and quality. The thesis presents the operation of a robot welding cell project, which was developed at YASKAWA Ristro d.o.o. for the customer Akrapovič. The sub systems of the robot welding cell will be detailed in the thesis including the following topics; safety c...

  10. Effects of deuterium oxide and galvanic vestibular stimulation on visual cortical cell function

    International Nuclear Information System (INIS)

    The spontaneous and evoked unit activities of complex visual cortical cells were recorded from Brodmann's area 18 in immobilized, unanesthetized cats before, during, and after stimulation of the vestibular system. The vestibular system was stimulated by intravenous injection of deuterium oxide (D2O)--a noted nystagmogenic agent--or by direct galvanic stimulation of the labyrinth. Measures of the receptive-field areas, poststimulus time histograms, directional preferences, and the optimal speed of the light bar stimulating the cell were obtained before and after the application of D2O. Directional preferences were determined in a novel manner, using a method derived from a hierarchical clustering technique. Data were collected and analyzed from a) visual cortical cells in cats with intact labyrinths, b) visual cortical cells in cats following bilateral labrinthectomies, and c) nonvisual cortical cells in cats with intact labyrinths. The other cellular characteristics were also altered by the D2O. Galvanic stimulation of the labyrinth resembles, in its effects, the injection of D2O. In labyrinth-intact cats, the time course of area 18 spontaneous activity dramatically increased 30 min or more after D2O was administered. It peaked 2-3 h later and still had not returned to preinjection levels even 7 h after the D2O administration. In bilaterally labyrinthectomized cats, the spontaneous activity of the visual cells did not change following D2O administration. In nonvisual cells from labyrinth-intact cats, the spontaneous activity demonstrated a slight but significant decrease over time after D2O injection. In pilot studies, the cats were injected with D2O. Within 8-10 min afterward, signs of positional nystagmus commenced; and within 30 min, problems in maintaining balance were noted. This continued for 7-8 h before disappearing. In the labyrinthectomized animals, such effects were not observed

  11. Effects of deuterium oxide and galvanic vestibular stimulation on visual cortical cell function

    Energy Technology Data Exchange (ETDEWEB)

    Reinis, S.; Landolt, J.P.; Weiss, D.S.; Money, K.E.

    1984-03-01

    The spontaneous and evoked unit activities of complex visual cortical cells were recorded from Brodmann's area 18 in immobilized, unanesthetized cats before, during, and after stimulation of the vestibular system. The vestibular system was stimulated by intravenous injection of deuterium oxide (D2O)--a noted nystagmogenic agent--or by direct galvanic stimulation of the labyrinth. Measures of the receptive-field areas, poststimulus time histograms, directional preferences, and the optimal speed of the light bar stimulating the cell were obtained before and after the application of D2O. Directional preferences were determined in a novel manner, using a method derived from a hierarchical clustering technique. Data were collected and analyzed from a) visual cortical cells in cats with intact labyrinths, b) visual cortical cells in cats following bilateral labrinthectomies, and c) nonvisual cortical cells in cats with intact labyrinths. The other cellular characteristics were also altered by the D2O. Galvanic stimulation of the labyrinth resembles, in its effects, the injection of D2O. In labyrinth-intact cats, the time course of area 18 spontaneous activity dramatically increased 30 min or more after D2O was administered. It peaked 2-3 h later and still had not returned to preinjection levels even 7 h after the D2O administration. In bilaterally labyrinthectomized cats, the spontaneous activity of the visual cells did not change following D2O administration. In nonvisual cells from labyrinth-intact cats, the spontaneous activity demonstrated a slight but significant decrease over time after D2O injection. In pilot studies, the cats were injected with D2O. Within 8-10 min afterward, signs of positional nystagmus commenced; and within 30 min, problems in maintaining balance were noted. This continued for 7-8 h before disappearing. In the labyrinthectomized animals, such effects were not observed.

  12. Mechanisms of daughter cell-size control during cell division.

    Science.gov (United States)

    Kiyomitsu, Tomomi

    2015-05-01

    Daughter cell size is tightly regulated during cell division. In animal cells, the position of the anaphase spindle specifies the cell cleavage site to dictate the relative size of the daughter cells. Although spindle orientation is regulated by dynein-dependent cortical pulling forces exerted on astral microtubules in many cell types, it was unclear how these forces are precisely regulated to center or displace the spindle. Recently, intrinsic signals derived from chromosomes or spindle poles have been demonstrated to regulate dynein-dependent pulling forces in symmetrically dividing cells. Unexpectedly, myosin-dependent contractile forces have also been shown to control spindle position by altering the cellular boundaries during anaphase. In this review, I discuss how dynein- and myosin-dependent forces are coordinately regulated to control daughter cell size. PMID:25548067

  13. NCS--a software for visual modeling and simulation of PWR nuclear power plant control system

    International Nuclear Information System (INIS)

    The modeling and simulation of nuclear power plant control system has been investigated. Some mathematical models for rapid and accurate simulation are derived, including core models, pressurizer model, steam generator model, etc. Several numerical methods such as Runge-Kutta Method and Treanor Method are adopted to solve the above system models. In order to model the control system conveniently, a block diagram-oriented visual modeling platform is designed. And the Discrete Similarity Method is used to calculate the control system models. A corresponding simulating software, NCS, is developed for researching on the control systems of commercial nuclear power plant. And some satisfactory results are obtained. The research works will be of referential and applying value to design and analysis of nuclear power plant control system

  14. Control points within the cell cycle

    International Nuclear Information System (INIS)

    Evidence of the temporal order of chromosomal DNA replication argues favorably for the view that the cell cycle is controlled by genes acting in sequence whose time of expression is determined by mitosis and the amount of nuclear DNA (2C vs 4C) in the cell. Gl and G2 appear to be carbohydrate dependent in that cells starved of either carbohydrate of phosphate fail to make these transitions. Cells deprived of nitrate, however, fail only at Gl to S transition indicating that the controls that operate in G1 differ from those that operate in G2. 46 references, 5 figures

  15. Control points within the cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Van' t Hof, J.

    1984-01-01

    Evidence of the temporal order of chromosomal DNA replication argues favorably for the view that the cell cycle is controlled by genes acting in sequence whose time of expression is determined by mitosis and the amount of nuclear DNA (2C vs 4C) in the cell. Gl and G2 appear to be carbohydrate dependent in that cells starved of either carbohydrate of phosphate fail to make these transitions. Cells deprived of nitrate, however, fail only at Gl to S transition indicating that the controls that operate in G1 differ from those that operate in G2. 46 references, 5 figures.

  16. SAVA 3: A testbed for integration and control of visual processes

    Science.gov (United States)

    Crowley, James L.; Christensen, Henrik

    1994-01-01

    The development of an experimental test-bed to investigate the integration and control of perception in a continuously operating vision system is described. The test-bed integrates a 12 axis robotic stereo camera head mounted on a mobile robot, dedicated computer boards for real-time image acquisition and processing, and a distributed system for image description. The architecture was designed to: (1) be continuously operating, (2) integrate software contributions from geographically dispersed laboratories, (3) integrate description of the environment with 2D measurements, 3D models, and recognition of objects, (4) capable of supporting diverse experiments in gaze control, visual servoing, navigation, and object surveillance, and (5) dynamically reconfiguarable.

  17. Controllability analysis of decentralised linear controllers for polymeric fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Serra, Maria; Aguado, Joaquin; Ansede, Xavier; Riera, Jordi [Institut de Robotica i Informatica Industrial, Universitat Politecnica de Catalunya - Consejo Superior de Investigaciones Cientificas, C. Llorens i Artigas 4, 08028 Barcelona (Spain)

    2005-10-10

    This work deals with the control of polymeric fuel cells. It includes a linear analysis of the system at different operating points, the comparison and selection of different control structures, and the validation of the controlled system by simulation. The work is based on a complex non linear model which has been linearised at several operating points. The linear analysis tools used are the Morari resiliency index, the condition number, and the relative gain array. These techniques are employed to compare the controllability of the system with different control structures and at different operating conditions. According to the results, the most promising control structures are selected and their performance with PI based diagonal controllers is evaluated through simulations with the complete non linear model. The range of operability of the examined control structures is compared. Conclusions indicate good performance of several diagonal linear controllers. However, very few have a wide operability range. (author)

  18. Visualization and cellular hierarchy inference of single-cell data using SPADE.

    Science.gov (United States)

    Anchang, Benedict; Hart, Tom D P; Bendall, Sean C; Qiu, Peng; Bjornson, Zach; Linderman, Michael; Nolan, Garry P; Plevritis, Sylvia K

    2016-07-01

    High-throughput single-cell technologies provide an unprecedented view into cellular heterogeneity, yet they pose new challenges in data analysis and interpretation. In this protocol, we describe the use of Spanning-tree Progression Analysis of Density-normalized Events (SPADE), a density-based algorithm for visualizing single-cell data and enabling cellular hierarchy inference among subpopulations of similar cells. It was initially developed for flow and mass cytometry single-cell data. We describe SPADE's implementation and application using an open-source R package that runs on Mac OS X, Linux and Windows systems. A typical SPADE analysis on a 2.27-GHz processor laptop takes ∼5 min. We demonstrate the applicability of SPADE to single-cell RNA-seq data. We compare SPADE with recently developed single-cell visualization approaches based on the t-distribution stochastic neighborhood embedding (t-SNE) algorithm. We contrast the implementation and outputs of these methods for normal and malignant hematopoietic cells analyzed by mass cytometry and provide recommendations for appropriate use. Finally, we provide an integrative strategy that combines the strengths of t-SNE and SPADE to infer cellular hierarchy from high-dimensional single-cell data. PMID:27310265

  19. High-definition optical coherence tomography enables visualization of individual cells in healthy skin

    DEFF Research Database (Denmark)

    Boone, Marc; Jemec, Gregor B E; Del Marmol, Véronique

    2012-01-01

    HD-OCT could be confirmed by the phantom analysis. The identification of cells in the epidermis can be made by both techniques. RCM offers the best lateral resolution, and HD-OCT has the best penetration depth, providing images of individual cells deeper within the dermis. Eccrine ducts and hair...... shafts with pilosebaceous units can be observed depending on skin site. HD-OCT provides morphological imaging with sufficient resolution and penetration depth to permit visualization of individual cells at up to 570 μm in depth offering the possibility of additional structural information complementary...

  20. Soure and Transmission Control for Wireless Visual Sensor Networks with Compressive Sensing and Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Lei You

    2013-05-01

    Full Text Available The lifetime of the emerging Wireless visual sensor network (WVSN is seriously dependent on the energy shored in the battery of its sensor nodes as well as the compression and resource allocation scheme. In this paper, the energy harvesting technology was adopted to provide almost perpetual operation of the WVSN and compressed-sensing-based encoding was used to decrease the power consumption of acquiring visual information at the front-end sensors. A Dynamic Source and Transmission Control Algorithm (DSTCA was proposed to jointly determine source rate, source energy consumption, and the allocation of transmission energy and available bandwidth under energy harvesting and queue stability constraints. A virtual energy queue was introduced to control the resource allocation and the measurement rate in each time slot. The algorithm can guarantee the stability of the visual data queues in all sensors and achieve near-optimal performance. The distributed implementation of the proposed algorithm was discussed and the achievable performance theorem was also given.

  1. Control Strivings in Attaining Peer-Group Membership and Forming Romantic Relationships among Adolescents with and without Visual Impairment

    Science.gov (United States)

    Pfeiffer, Jens P.; Pinquart, Martin

    2011-01-01

    This study compared control striving with regard to two developmental goals in adolescents with visual impairment and sighted peers. A matched-pair design was used with 158 adolescents with visual impairment and 158 sighted peers by using age, gender, habitation (living with ones' parents vs. other forms of living), and socioeconomic status as…

  2. A Brain Computer Interface for Robust Wheelchair Control Application Based on Pseudorandom Code Modulated Visual Evoked Potential

    DEFF Research Database (Denmark)

    Mohebbi, Ali; Engelsholm, Signe K.D.; Puthusserypady, Sadasivan;

    2015-01-01

    In this pilot study, a novel and minimalistic Brain Computer Interface (BCI) based wheelchair control application was developed. The system was based on pseudorandom code modulated Visual Evoked Potentials (c-VEPs). The visual stimuli in the scheme were generated based on the Gold code, and the...

  3. Combining Dense Structure From Motion and Visual SLAM in a Behavior-Based Robot Control Architecture

    Directory of Open Access Journals (Sweden)

    Geert De Cubber

    2010-02-01

    Full Text Available In this paper, we present a control architecture for an intelligent outdoor mobile robot. This enables the robot to navigate in a complex, natural outdoor environment, relying on only a single on-board camera as sensory input. This is achieved through a twofold analysis of the visual data stream: a dense structure from motion algorithm calculates a depth map of the environment and a visual simultaneous localization and mapping algorithm builds a map of the surroundings using image features. This information enables a behavior-based robot motion and path planner to navigate the robot through the environment. In this paper, we show the theoretical aspects of setting up this architecture.

  4. Visualization of flow separation and control by vortex generators on an single flap in landing configuration

    Directory of Open Access Journals (Sweden)

    Matějka Milan

    2012-04-01

    Full Text Available This paper focuses on a suppression of the flow separation, which occurs on a deflected flap, by means of vortex generators (VG's. An airfoil NACA 63A421 with a simple flap and vane-type vortex generators were used. The investigation was carried out by using experimental and numerical methods. The data from the numerical simulation of the flapped airfoil without VG's control were used for the vortex generator design. Two sizes, two different shapes and various spacing of the vortex generators were tested. The flow past the airfoil was visualized through three methods, namely tuft filaments technique, oil and thermo camera visualization. The experiments were performed in closed circuit wind tunnels with closed and open test sections. The lift curves for both cases without and with vortex generators were acquired for a lift coefficient improvement determination. The improvement was achieved for several cases by means all of the applied methods.

  5. Effectiveness of basic display augmentation in vehicular control by visual field cues

    Science.gov (United States)

    Grunwald, A. J.; Merhav, S. J.

    1978-01-01

    The paper investigates the effectiveness of different basic display augmentation concepts - fixed reticle, velocity vector, and predicted future vehicle path - for RPVs controlled by a vehicle-mounted TV camera. The task is lateral manual control of a low flying RPV along a straight reference line in the presence of random side gusts. The man-machine system and the visual interface are modeled as a linear time-invariant system. Minimization of a quadratic performance criterion is assumed to underlie the control strategy of a well-trained human operator. The solution for the optimal feedback matrix enables the explicit computation of the variances of lateral deviation and directional error of the vehicle and of the control force that are used as performance measures.

  6. Visual Servoing Tracking Control of a Ball and Plate System: Design, Implementation and Experimental Validation

    Directory of Open Access Journals (Sweden)

    Ming-Tzu Ho

    2013-07-01

    Full Text Available This paper presents the design, implementation and validation of real‐time visual servoing tracking control for a ball and plate system. The position of the ball is measured with a machine vision system. The image processing algorithms of the machine vision system are pipelined and implemented on a field programmable gate array (FPGA device to meet real‐ time constraints. A detailed dynamic model of the system is derived for the simulation study.By neglecting the high‐order coupling terms, the ball and plate system model is simplified into two decoupled ball and beam systems, and an approximate input‐ output feedback linearization approach is then used to design the controller for trajectory tracking. The designed control law is implemented on a digital signal processor (DSP. The validity of the performance of the developed control system is investigated through simulation and experimental studies. Experimental results show that the designed system functions well with reasonable agreement with simulations.

  7. Study on global control network precision positioning method in visual shape measurement

    Science.gov (United States)

    Long, Chang-yu; Zhu, Ji-gui

    2013-08-01

    Large-size visual shape measurement based on ICP (iterative closest point) mosaicing algorithm generally has a larger cumulative error; however, this problem can be well solved by precision positioning global control network. Therefore, this method is widely used in large-size visual shape measurement. Since the positioning accuracy of the global control network is the key influencing factor of the final measurement accuracy, the method of precision positioning global control network is researched, which is dependent on the principle of portable close-range photogrammetry. The precision positioning theory and mathematical model of global control network are investigated in this paper. Bundle adjustment optimization algorithm is the core of this measurement system, the solution method of this algorithm is introduced in detail, which can improve the model solution accuracy. As is known, the initial value of the algorithm has a direct influence on the convergence of the result, so obtaining the initial value is a key part of the measurement system, including control points matching technology, stations orientation technology and the technology of obtaining the initial value of the three-dimensional coordinates of global control points. New technological breakthroughs were made based on the existing researches to get a more precious and stable initial value. Firstly, a nonlinear adjustment model based control points matching method is proposed, which significantly improves the correct matching rate when the control points distribute intensively. Secondly, a new station orientation method without using an external orientation device is studied, which greatly improves the shooting freedom and expands the range of the spatial distribution of the measurement stations. Finally, a camera calibration method independent with the imaging model is explored, which converts image coordinate information into image angle information. Thus, the initial value calculation accuracy of

  8. Immunological control of adult neural stem cells

    OpenAIRE

    Gonzalez-Perez, Oscar; Quiñones-Hinojosa, Alfredo; Garcia-Verdugo, Jose Manuel

    2010-01-01

    Adult neurogenesis occurs only in discrete regions of adult central nervous system: the subventricular zone and the subgranular zone. These areas are populated by adult neural stem cells (aNSC) that are regulated by a number of molecules and signaling pathways, which control their cell fate choices, survival and proliferation rates. For a long time, it was believed that the immune system did not exert any control on neural proliferative niches. However, it has been observed that many patholog...

  9. Calcium dynamics in root cells of Arabidopsis thaliana visualized with selective plane illumination microscopy.

    Directory of Open Access Journals (Sweden)

    Alex Costa

    Full Text Available Selective Plane Illumination Microscopy (SPIM is an imaging technique particularly suited for long term in-vivo analysis of transparent specimens, able to visualize small organs or entire organisms, at cellular and eventually even subcellular resolution. Here we report the application of SPIM in Calcium imaging based on Förster Resonance Energy Transfer (FRET. Transgenic Arabidopsis plants expressing the genetically encoded-FRET-based Ca(2+ probe Cameleon, in the cytosol or nucleus, were used to demonstrate that SPIM enables ratiometric fluorescence imaging at high spatial and temporal resolution, both at tissue and single cell level. The SPIM-FRET technique enabled us to follow nuclear and cytosolic Ca(2+ dynamics in Arabidopsis root tip cells, deep inside the organ, in response to different stimuli. A relevant physiological phenomenon, namely Ca(2+ signal percolation, predicted in previous studies, has been directly visualized.

  10. Adaptation of handwriting size under distorted visual feedback in patients with Parkinson's disease and elderly and young controls

    OpenAIRE

    Teulings, H; Contreras-Vidal, J; Stelmach, G; Adler, C.

    2002-01-01

    Objective: The ability to use visual feedback to control handwriting size was compared in patients with Parkinson's disease (PD), elderly people, and young adults to better understand factors playing a part in parkinsonian micrographia.

  11. The Emergence of Contrast-Invariant Orientation Tuning in Simple Cells of Cat Visual Cortex

    OpenAIRE

    Finn, Ian M.; Priebe, Nicholas J.; Ferster, David

    2007-01-01

    Simple cells in primary visual cortex exhibit contrast-invariant orientation tuning, in seeming contradiction to feed-forward models relying on lateral geniculate nucleus (LGN) input alone. Contrast invariance has therefore been thought to depend on the presence of intracortical lateral inhibition. In vivo intracellular recordings instead suggest that contrast invariance can be explained by three properties of the excitatory pathway. 1) Depolarizations evoked by orthogonal stimuli are determi...

  12. Quantitative o perando visualization of the energy band depth profile in solar cells

    OpenAIRE

    Chen, Qi; Mao, Lin; LI, YAOWEN; Kong, Tao; Wu, Na; Ma, Changqi; Bai, Sai; Jin, Yizheng; Wu, Dan; Lu, Wei; Wang, Bing; Chen, Liwei

    2015-01-01

    The energy band alignment in solar cell devices is critically important because it largely governs elementary photovoltaic processes, such as the generation, separation, transport, recombination and collection of charge carriers. Despite the expenditure of considerable effort, the measurement of energy band depth profiles across multiple layers has been extremely challenging, especially for operando devices. Here we present direct visualization of the surface potential depth profile over the ...

  13. Phase-dependent visual control of the zigzag paths of navigating wood ants.

    Science.gov (United States)

    Lent, David D; Graham, Paul; Collett, Thomas S

    2013-12-01

    Animals sometimes take sinuous paths to a goal. Insects, tracking an odor trail on the ground [1-3] or moving up an odor plume in the air [4, 5], generally follow zigzag paths. Some insects [6-8] take a zigzag approach to visual targets, perhaps to obtain parallax information. How does an animal keep its overall path in the direction of the goal without disrupting a zigzag pattern? We describe here the wood ant's strategy when guided by a familiar visual scene. If their travel direction is correct, ants face the goal briefly after each turning point along their zigzag path. If the direction is wrong, they turn rapidly at this point to place the scene correctly on their retina. Such saccade-like turns are rare elsewhere in the zigzag. Similarly, when the scene is made to jump to a new position on their retina, ants wait until an expected goal-facing phase of the zigzag before turning to correct the imposed error. Correctly timed, intermittent control allows an animal to adjust its path without compromising additional roles for the zigzag pattern in gathering visual information or in using odor cues for guidance. PMID:24268412

  14. 3D Data Mapping and Real-Time Experiment Control and Visualization in Brain Slices.

    Science.gov (United States)

    Navarro, Marco A; Hibbard, Jaime V K; Miller, Michael E; Nivin, Tyler W; Milescu, Lorin S

    2015-10-20

    Here, we propose two basic concepts that can streamline electrophysiology and imaging experiments in brain slices and enhance data collection and analysis. The first idea is to interface the experiment with a software environment that provides a 3D scene viewer in which the experimental rig, the brain slice, and the recorded data are represented to scale. Within the 3D scene viewer, the user can visualize a live image of the sample and 3D renderings of the recording electrodes with real-time position feedback. Furthermore, the user can control the instruments and visualize their status in real time. The second idea is to integrate multiple types of experimental data into a spatial and temporal map of the brain slice. These data may include low-magnification maps of the entire brain slice, for spatial context, or any other type of high-resolution structural and functional image, together with time-resolved electrical and optical signals. The entire data collection can be visualized within the 3D scene viewer. These concepts can be applied to any other type of experiment in which high-resolution data are recorded within a larger sample at different spatial and temporal coordinates. PMID:26488641

  15. Electrophysiological evidence that top-down knowledge controls working memory processing for subsequent visual search.

    Science.gov (United States)

    Kawashima, Tomoya; Matsumoto, Eriko

    2016-03-23

    Items in working memory guide visual attention toward a memory-matching object. Recent studies have shown that when searching for an object this attentional guidance can be modulated by knowing the probability that the target will match an item in working memory. Here, we recorded the P3 and contralateral delay activity to investigate how top-down knowledge controls the processing of working memory items. Participants performed memory task (recognition only) and memory-or-search task (recognition or visual search) in which they were asked to maintain two colored oriented bars in working memory. For visual search, we manipulated the probability that target had the same color as memorized items (0, 50, or 100%). Participants knew the probabilities before the task. Target detection in 100% match condition was faster than that in 50% match condition, indicating that participants used their knowledge of the probabilities. We found that the P3 amplitude in 100% condition was larger than in other conditions and that contralateral delay activity amplitude did not vary across conditions. These results suggest that more attention was allocated to the memory items when observers knew in advance that their color would likely match a target. This led to better search performance despite using qualitatively equal working memory representations. PMID:26872100

  16. Control of humanoid robot via motion-onset visual evoked potentials.

    Science.gov (United States)

    Li, Wei; Li, Mengfan; Zhao, Jing

    2014-01-01

    This paper investigates controlling humanoid robot behavior via motion-onset specific N200 potentials. In this study, N200 potentials are induced by moving a blue bar through robot images intuitively representing robot behaviors to be controlled with mind. We present the individual impact of each subject on N200 potentials and discuss how to deal with individuality to obtain a high accuracy. The study results document the off-line average accuracy of 93% for hitting targets across over five subjects, so we use this major component of the motion-onset visual evoked potential (mVEP) to code people's mental activities and to perform two types of on-line operation tasks: navigating a humanoid robot in an office environment with an obstacle and picking-up an object. We discuss the factors that affect the on-line control success rate and the total time for completing an on-line operation task. PMID:25620918

  17. Brief Report: Cognitive Control of Social and Nonsocial Visual Attention in Autism.

    Science.gov (United States)

    DiCriscio, Antoinette Sabatino; Miller, Stephanie J; Hanna, Eleanor K; Kovac, Megan; Turner-Brown, Lauren; Sasson, Noah J; Sapyta, Jeffrey; Troiani, Vanessa; Dichter, Gabriel S

    2016-08-01

    Prosaccade and antisaccade errors in the context of social and nonsocial stimuli were investigated in youth with autism spectrum disorder (ASD; n = 19) a matched control sample (n = 19), and a small sample of youth with obsessive compulsive disorder (n = 9). Groups did not differ in error rates in the prosaccade condition for any stimulus category. In the antisaccade condition, the ASD group demonstrated more errors than the control group for nonsocial stimuli related to circumscribed interests, but not for other nonsocial stimuli or for social stimuli. Additionally, antisaccade error rates were predictive of core ASD symptom severity. Results indicate that the cognitive control of visual attention in ASD is impaired specifically in the context of nonsocial stimuli related to circumscribed interests. PMID:27177893

  18. Comparison of Mars Science Laboratory Reaction Control System Jet Computations With Flow Visualization and Velocimetry

    Science.gov (United States)

    Bathel, Brett F.; Danehy, Paul M.; Johansen, Craig T.; Ashcraft, Scott W.; Novak, Luke A.

    2013-01-01

    Numerical predictions of the Mars Science Laboratory reaction control system jets interacting with a Mach 10 hypersonic flow are compared to experimental nitric oxide planar laser-induced fluorescence data. The steady Reynolds Averaged Navier Stokes equations using the Baldwin-Barth one-equation turbulence model were solved using the OVERFLOW code. The experimental fluorescence data used for comparison consists of qualitative two-dimensional visualization images, qualitative reconstructed three-dimensional flow structures, and quantitative two-dimensional distributions of streamwise velocity. Through modeling of the fluorescence signal equation, computational flow images were produced and directly compared to the qualitative fluorescence data.

  19. Visual control of steering in the box jellyfish Tripedalia cystophora

    DEFF Research Database (Denmark)

    Petie, Ronald; Garm, Anders; Nilsson, Dan-Eric

    2011-01-01

    darkening of one quadrant of the equatorial visual world by (1) increasing pulse frequency, (2) creating an asymmetry in the structure that constricts the outflow opening of the bell, the velarium, and (3) delaying contraction at one of the four sides of the bell. This causes the animals to orient their...... recorded changes in their swimming behaviour. Animals were tethered in a small experimental chamber, where we could control lighting conditions. The behaviour of the animals was quantified by tracking the movements of the bell, using a high-speed camera. We found that the animals respond predictably to the...

  20. Infrared Thermography as a Visualization Tool of Flow Control by Vortex Generators

    Czech Academy of Sciences Publication Activity Database

    Součková, Natálie; Kuklová, J.; Popelka, Lukáš; Matějka, M.

    Prague: Institute of Thermomechanics AS CR, v. v. i., 2010 - (Jonáš, P.; Uruba, V.), s. 1-9 ISBN 978-80-87012-27-7. [Colloquium Fluid Dynamics 2010. Praha (CZ), 20.10.2010-22.10.2010] R&D Projects: GA MŠk(CZ) 1M06031; GA ČR GAP101/10/1230; GA ČR GA101/08/1112; GA ČR GA103/09/0977 Institutional research plan: CEZ:AV0Z20760514 Keywords : infrared thermography visualization * vortex generators * flow control Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts

  1. Machine-Part cell formation through visual decipherable clustering of Self Organizing Map

    CERN Document Server

    Chattopadhyay, Manojit; Dan, Pranab K; 10.1007/s00170-010-2802-4

    2011-01-01

    Machine-part cell formation is used in cellular manufacturing in order to process a large variety, quality, lower work in process levels, reducing manufacturing lead-time and customer response time while retaining flexibility for new products. This paper presents a new and novel approach for obtaining machine cells and part families. In the cellular manufacturing the fundamental problem is the formation of part families and machine cells. The present paper deals with the Self Organising Map (SOM) method an unsupervised learning algorithm in Artificial Intelligence, and has been used as a visually decipherable clustering tool of machine-part cell formation. The objective of the paper is to cluster the binary machine-part matrix through visually decipherable cluster of SOM color-coding and labelling via the SOM map nodes in such a way that the part families are processed in that machine cells. The Umatrix, component plane, principal component projection, scatter plot and histogram of SOM have been reported in t...

  2. Self-Control and Impulsiveness in Nondieting Adult Human Females: Effects of Visual Food Cues and Food Deprivation

    Science.gov (United States)

    Forzano, Lori-Ann B.; Chelonis, John J.; Casey, Caitlin; Forward, Marion; Stachowiak, Jacqueline A.; Wood, Jennifer

    2010-01-01

    Self-control can be defined as the choice of a larger, more delayed reinforcer over a smaller, less delayed reinforcer, and impulsiveness as the opposite. Previous research suggests that exposure to visual food cues affects adult humans' self-control. Previous research also suggests that food deprivation decreases adult humans' self-control. The…

  3. An Experimental Comparison of Two Methods Of Teaching Numerical Control Manual Programming Concepts; Visual Media Versus Hands-On Equipment.

    Science.gov (United States)

    Biekert, Russell

    Accompanying the rapid changes in technology has been a greater dependence on automation and numerical control, which has resulted in the need to find ways of preparing programers for industrial machines using numerical control. To compare the hands-on equipment method and a visual media method of teaching numerical control, an experimental and a…

  4. Analysis of action tremor and impaired control of movement velocity in multiple sclerosis during visually guided wrist-tracking tasks.

    Science.gov (United States)

    Liu, X; Miall, C; Aziz, T Z; Palace, J A; Haggard, P N; Stein, J F

    1997-11-01

    We investigated the relationship between action tremor (AT) and impaired control of movement velocity (MV) in visually guided tracking tasks, in normal subjects and in patients with multiple sclerosis (MS) with or without motor deficits. The effects of withdrawing visual feedback of either the target or the cursor were then investigated. Visually cued simple reaction times (SRTs) were also measured. The effects of thalamotomy on motor performance in these tasks were evaluated in seven patients. In the MS patients with tremor, there was no correlation between AT and impairment in control of MV, but the latter was highly correlated with an increased delay in SRT. Withdrawal of visually guiding cues increased the error significantly in MV, but reduced AT by approximately 30% in magnitude. Frequency analysis indicated that the AT had two components: (a) non-visual-dependent, oscillatory movements, mainly at 4 Hz; and (2) visual-dependent, repetitive movements, with significant power at 1-2 Hz. Thalamotomy significantly reduced AT but hardly improved accuracy in MV. These results suggest that visual feedback of a spatial mismatch signal may provoke a visually dependent repetitive movement contributing to AT. Conduction delays along either the cortico-cerebello-cortical or the proprioceptive pathways and impaired working memory caused by MS may be responsible for the movement disorders in these patients. PMID:9399226

  5. Control of differentiation of melanoma cells

    International Nuclear Information System (INIS)

    To develop the method to induce the appearance of differentiation in amelanotic melanoma, experimental control of differentiation in B-16 melanoma cells of mice was discussed. Human melanoma cells and yellow melanin pigment cells useful for a fundamental study of radiotherapy for cancer were cultured and were differentiated into some lines. Melanotic B-16 cells and amelanotic B-16 cells were irradiated with thermal neutron (neutron: 2.7 x 1012, γ-dose: 32.3 rad) after they were cultured in culture solution containing 10 γ/ml of 10B-dopa for 13 hours. A fine structure 5 hours after the irradiation in one of 5 experimental cases showed aggregated disintegration of melanin pigment particles, markedly deformed and fragmentized nucleus, and structural changes in cell membrane. (Tsunoda, M.)

  6. Controlled regular locomotion of algae cell microrobots.

    Science.gov (United States)

    Xie, Shuangxi; Jiao, Niandong; Tung, Steve; Liu, Lianqing

    2016-06-01

    Algae cells can be considered as microrobots from the perspective of engineering. These organisms not only have a strong reproductive ability but can also sense the environment, harvest energy from the surroundings, and swim very efficiently, accommodating all these functions in a body of size on the order of dozens of micrometers. An interesting topic with respect to random swimming motions of algae cells in a liquid is how to precisely control them as microrobots such that they swim according to manually set routes. This study developed an ingenious method to steer swimming cells based on the phototaxis. The method used a varying light signal to direct the motion of the cells. The swimming trajectory, speed, and force of algae cells were analyzed in detail. Then the algae cell could be controlled to swim back and forth, and traverse a crossroad as a microrobot obeying specific traffic rules. Furthermore, their motions along arbitrarily set trajectories such as zigzag, and triangle were realized successfully under optical control. Robotize algae cells can be used to precisely transport and deliver cargo such as drug particles in microfluidic chip for biomedical treatment and pharmacodynamic analysis. The study findings are expected to bring significant breakthrough in biological drives and new biomedical applications. PMID:27206511

  7. A two- and three-dimensional approach for visualizing human embryonic stem cell differentiation

    DEFF Research Database (Denmark)

    Brøchner, Christian Beltoft; Vestentoft, Peter S; Lynnerup, Niels;

    2010-01-01

    Undifferentiated human embryonic stem cells are characterized by expression of specific cell markers like the transcription factors OCT4, SOX2, and NANOG, the stage-specific embryonic antigen SSEA4, and the tumor-related antigens TRA-1-60 and TRA-1-81 and by their ability to differentiate under...... accomplished. An extended version of this technique even allows for a high-magnification 3D-reconstruction of an area of interest (AOI), e.g., the developing hepatic stem cells. These techniques allow both a 2D and a 3D visualization of hESC colonies and lead to new insights into and information about the...... interaction of stem cells....

  8. Visual control of wheeled mobile robots unifying vision and control in generic approaches

    CERN Document Server

    Becerra, Héctor M

    2014-01-01

    Vision-based control of wheeled mobile robots is an interesting field of research from a scientific and even social point of view due to its potential applicability. This book presents a formal treatment of some aspects of control theory applied to the problem of vision-based pose regulation of wheeled mobile robots. In this problem, the robot has to reach a desired position and orientation, which are specified by a target image. It is faced in such a way that vision and control are unified to achieve stability of the closed loop, a large region of convergence, without local minima, and good robustness against parametric uncertainty. Three different control schemes that rely on monocular vision as unique sensor are presented and evaluated experimentally. A common benefit of these approaches is that they are valid for imaging systems obeying approximately a central projection model, e.g., conventional cameras, catadioptric systems and some fisheye cameras. Thus, the presented control schemes are generic approa...

  9. Reduction in Dynamic Visual Acuity Reveals Gaze Control Changes Following Spaceflight

    Science.gov (United States)

    Peters, Brian T.; Brady, Rachel A.; Miller, Chris; Lawrence, Emily L.; Mulavara Ajitkumar P.; Bloomberg, Jacob J.

    2010-01-01

    INTRODUCTION: Exposure to microgravity causes adaptive changes in eye-head coordination that can lead to altered gaze control. This could affect postflight visual acuity during head and body motion. The goal of this study was to characterize changes in dynamic visual acuity after long-duration spaceflight. METHODS: Dynamic Visual Acuity (DVA) data from 14 astro/cosmonauts were collected after long-duration (6 months) spaceflight. The difference in acuity between seated and walking conditions provided a metric of change in the subjects ability to maintain gaze fixation during self-motion. In each condition, a psychophysical threshold detection algorithm was used to display Landolt ring optotypes at a size that was near each subject s acuity threshold. Verbal responses regarding the orientation of the gap were recorded as the optotypes appeared sequentially on a computer display 4 meters away. During the walking trials, subjects walked at 6.4 km/h on a motorized treadmill. RESULTS: A decrement in mean postflight DVA was found, with mean values returning to baseline within 1 week. The population mean showed a consistent improvement in DVA performance, but it was accompanied by high variability. A closer examination of the individual subject s recovery curves revealed that many did not follow a pattern of continuous improvement with each passing day. When adjusted on the basis of previous long-duration flight experience, the population mean shows a "bounce" in the re-adaptation curve. CONCLUSION: Gaze control during self-motion is altered following long-duration spaceflight and changes in postflight DVA performance indicate that vestibular re-adaptation may be more complex than a gradual return to normal.

  10. A visual cell for measuring the solubility of prograde soluble salts in water at high temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Moore, R.C.; Simonson, J.M.; Mesmer, R.E.

    1994-10-01

    An apparatus has been constructed for measuring the solubility of prograde soluble salts in water at high temperatures and pressures. The apparatus consists of a visually accessible cell thermostated in a rocking furnace. The apparatus allows for rapid, accurate solubility measurements for temperatures over 650 K and pressures up to 170 bars. The cell was constructed of platinum with sapphire windows and gold seals for corrosion resistance. A 3x telescope is used to observe the phase change in the cell. A key feature of the cell is the ability to control the system pressure. A section of small bore platinum tubing is used to connect the cell to an external pressure source. The tubing can remain open to the pressure source or be sealed off during a measurement. To minimize equilibration times, the entire apparatus was mounted to a rocking frame which can operate in the horizontal or vertical position. The apparatus was tested by measuring the solubility of NaCl in water at temperatures between 345 and 516 K at saturation pressure. Results are in good agreement with existing literature values.

  11. Application of Visual MODFLOW in the research on water control in certain mine

    International Nuclear Information System (INIS)

    Visual MODFLOW is used to construct three-dimension groundwater numerical model based on analyzing the geohydrologic conditions of certain mine which have big inflow of water and complicated geohydrologic conditions. A numerical method was applied to calculate water inflow of the mine. Compared with the result obtained by big well method,the result obtained by the numerical method was more accurate. A method of combining surface and underground water control was selected, which was based on the surface control and supplemented by underground control. To prevent the rain flow into groundwater three methods of intercepting drain, drainage ditch and karts filled on surface were used. Three methods of anti-seepage curtain, draining water immediately and pump wells were used for underground water control. The water control engineering was applied in the numerical model of this mine. The result showed that the combined method was feasible and economic. After using these water control methods, the water inflow would be dramatically reduced, the cost would be decreased, and the environment can be protected. (authors)

  12. Control of cell volume in skeletal muscle.

    Science.gov (United States)

    Usher-Smith, Juliet A; Huang, Christopher L-H; Fraser, James A

    2009-02-01

    Regulation of cell volume is a fundamental property of all animal cells and is of particular importance in skeletal muscle where exercise is associated with a wide range of cellular changes that would be expected to influence cell volume. These complex electrical, metabolic and osmotic changes, however, make rigorous study of the consequences of individual factors on muscle volume difficult despite their likely importance during exercise. Recent charge-difference modelling of cell volume distinguishes three major aspects to processes underlying cell volume control: (i) determination by intracellular impermeant solute; (ii) maintenance by metabolically dependent processes directly balancing passive solute and water fluxes that would otherwise cause cell swelling under the influence of intracellular membrane-impermeant solutes; and (iii) volume regulation often involving reversible short-term transmembrane solute transport processes correcting cell volumes towards their normal baselines in response to imposed discrete perturbations. This review covers, in turn, the main predictions from such quantitative analysis and the experimental consequences of comparable alterations in extracellular pH, lactate concentration, membrane potential and extracellular tonicity. The effects of such alterations in the extracellular environment in resting amphibian muscles are then used to reproduce the intracellular changes that occur in each case in exercising muscle. The relative contributions of these various factors to the control of cell volume in resting and exercising skeletal muscle are thus described. PMID:19133959

  13. A lower limb exoskeleton control system based on steady state visual evoked potentials

    Science.gov (United States)

    Kwak, No-Sang; Müller, Klaus-Robert; Lee, Seong-Whan

    2015-10-01

    Objective. We have developed an asynchronous brain-machine interface (BMI)-based lower limb exoskeleton control system based on steady-state visual evoked potentials (SSVEPs). Approach. By decoding electroencephalography signals in real-time, users are able to walk forward, turn right, turn left, sit, and stand while wearing the exoskeleton. SSVEP stimulation is implemented with a visual stimulation unit, consisting of five light emitting diodes fixed to the exoskeleton. A canonical correlation analysis (CCA) method for the extraction of frequency information associated with the SSVEP was used in combination with k-nearest neighbors. Main results. Overall, 11 healthy subjects participated in the experiment to evaluate performance. To achieve the best classification, CCA was first calibrated in an offline experiment. In the subsequent online experiment, our results exhibit accuracies of 91.3 ± 5.73%, a response time of 3.28 ± 1.82 s, an information transfer rate of 32.9 ± 9.13 bits/min, and a completion time of 1100 ± 154.92 s for the experimental parcour studied. Significance. The ability to achieve such high quality BMI control indicates that an SSVEP-based lower limb exoskeleton for gait assistance is becoming feasible.

  14. Visual Attention Allocation Between Robotic Arm and Environmental Process Control: Validating the STOM Task Switching Model

    Science.gov (United States)

    Wickens, Christopher; Vieanne, Alex; Clegg, Benjamin; Sebok, Angelia; Janes, Jessica

    2015-01-01

    Fifty six participants time shared a spacecraft environmental control system task with a realistic space robotic arm control task in either a manual or highly automated version. The former could suffer minor failures, whose diagnosis and repair were supported by a decision aid. At the end of the experiment this decision aid unexpectedly failed. We measured visual attention allocation and switching between the two tasks, in each of the eight conditions formed by manual-automated arm X expected-unexpected failure X monitoring- failure management. We also used our multi-attribute task switching model, based on task attributes of priority interest, difficulty and salience that were self-rated by participants, to predict allocation. An un-weighted model based on attributes of difficulty, interest and salience accounted for 96 percent of the task allocation variance across the 8 different conditions. Task difficulty served as an attractor, with more difficult tasks increasing the tendency to stay on task.

  15. Formation of visual memories controlled by gamma power phase-locked to alpha oscillations

    Science.gov (United States)

    Park, Hyojin; Lee, Dong Soo; Kang, Eunjoo; Kang, Hyejin; Hahm, Jarang; Kim, June Sic; Chung, Chun Kee; Jiang, Haiteng; Gross, Joachim; Jensen, Ole

    2016-06-01

    Neuronal oscillations provide a window for understanding the brain dynamics that organize the flow of information from sensory to memory areas. While it has been suggested that gamma power reflects feedforward processing and alpha oscillations feedback control, it remains unknown how these oscillations dynamically interact. Magnetoencephalography (MEG) data was acquired from healthy subjects who were cued to either remember or not remember presented pictures. Our analysis revealed that in anticipation of a picture to be remembered, alpha power decreased while the cross-frequency coupling between gamma power and alpha phase increased. A measure of directionality between alpha phase and gamma power predicted individual ability to encode memory: stronger control of alpha phase over gamma power was associated with better memory. These findings demonstrate that encoding of visual information is reflected by a state determined by the interaction between alpha and gamma activity.

  16. The role of cell adhesion molecules in visual circuit formation: From neurite outgrowth to maps and synaptic specificity

    OpenAIRE

    Missaire, Mégane; Hindges, Robert

    2015-01-01

    ABSTRACT The formation of visual circuitry is a multistep process that involves cell–cell interactions based on a range of molecular mechanisms. The correct implementation of individual events, including axon outgrowth and guidance, the formation of the topographic map, or the synaptic targeting of specific cellular subtypes, are prerequisites for a fully functional visual system that is able to appropriately process the information captured by the eyes. Cell adhesion molecules (CAMs) with th...

  17. Interactions of multiwalled carbon nanotubes with algal cells: quantification of association, visualization of uptake, and measurement of alterations in the composition of cells.

    Science.gov (United States)

    Rhiem, Stefan; Riding, Matthew J; Baumgartner, Werner; Martin, Francis L; Semple, Kirk T; Jones, Kevin C; Schäffer, Andreas; Maes, Hanna M

    2015-01-01

    Carbon nanotubes (CNTs) are considered promising materials in nanotechnology. We quantified CNT accumulation by the alga Desmodesmus subspicatus. Cells were exposed to radiolabeled CNTs ((14)C-CNTs;1 mg/L) to determine uptake and association, as well as elimination and dissociation in clear media.Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) was used to detect effects of CNTs on algae. CNT-cell interactions were visualized by electron microscopy and related to alterations in their cell composition. A concentration factor of 5000 L/kg dry weight was calculated. Most of the material agglomerated around the cells, but single tubes were detected in the cytoplasm. Computational analyses of the ATR-FTIR data showed that CNT treated algae differed from controls at all sampling times.CNT exposure changed the biochemical composition of cells. The fact that CNTs are bioavailable for algae and that they influence the cell composition is important with regard to environmental risk assessment of this nanomaterial. PMID:25467692

  18. Wave propagation visualization in an experimental model for a control rod drive mechanism assembly

    International Nuclear Information System (INIS)

    Highlights: → We fabricate a full-scale mock-up of the control rod drive mechanism (CRDM) assembly in the upper reactor head of the nuclear power plant. → An ultrasonic propagation imaging method using a scanning laser ultrasonic generator is proposed to visualize and simulate ultrasonic wave propagation around the CRDM assembly. → The ultrasonic source location and frequency are simulated by changing the sensor location and the band pass-filtering zone. → The ultrasonic propagation patterns before and after cracks in the weld and nozzle of the CRDM assembly are analyzed. - Abstract: Nondestructive inspection techniques such as ultrasonic testing, eddy current testing, and visual testing are being developed to detect primary water stress corrosion cracks in control rod drive mechanism (CRDM) assemblies of nuclear power plants. A unit CRDM assembly consists of a reactor upper head including cladding, a penetration nozzle, and J-groove dissimilar metal welds with buttering. In this study, we fabricated a full-scale CRDM assembly mock-up. An ultrasonic propagation imaging (UPI) method using a scanning laser ultrasonic generator is proposed to visualize and simulate ultrasonic wave propagation around the thick and complex CRDM assembly. First, the proposed laser UPI system was validated for a simple aluminium plate by comparing the ultrasonic wave propagation movie (UWPM) obtained using the system with numerical simulation results reported in the literature. Lamb wave mode identification and damage detectability, depending on the ultrasonic frequency, were also included in the UWPM analysis. A CRDM assembly mock-up was fabricated in full-size and its vertical cross section was scanned using the laser UPI system to investigate the propagation characteristics of the longitudinal and Rayleigh waves in the complex structure. The ultrasonic source location and frequency were easily simulated by changing the sensor location and the band pass filtering zone

  19. Crop quality control system : a tool to control the visual quality of pot plants

    OpenAIRE

    Dijkshoorn-Dekker, M.W.C.

    2002-01-01

    Key words: quality, growth, model, leaf unfolding rate, internode, plant height, plant width, leaf area, temperature, plant spacing, season, light, development, image processing, grading, neural network, pot plant, Ficus benjamina 'Exotica'.The market is increasingly dictating the specifications for products. A well-defined marketable product must be delivered at a defined moment in time. A system was developed for growers to control development and growth of pot plants to achieve a defined q...

  20. One of the most well-established age-related changes in neural activity disappears after controlling for visual acuity.

    Science.gov (United States)

    Porto, Fábio H G; Tusch, Erich S; Fox, Anne M; Alperin, Brittany R; Holcomb, Phillip J; Daffner, Kirk R

    2016-04-15

    Numerous studies using a variety of imaging techniques have reported age-related differences in neural activity while subjects carry out cognitive tasks. Surprisingly little attention has been paid to the potential impact of age-associated changes in sensory acuity on these findings. Studies in the visual modality frequently report that their subjects had "normal or corrected- to-normal vision." However, in most cases, there is no indication that visual acuity was actually measured, and it is likely that the investigators relied largely on self-reported visual status of subjects, which is often inaccurate. We investigated whether differences in visual acuity influence one of the most commonly observed findings in the event-related potentials literature on cognitive aging, a reduction in posterior P3b amplitude, which is an index of cognitive decision-making/updating. Well-matched young (n=26) and old adults (n=29) participated in a visual oddball task. Measured visual acuity with corrective lenses was worse in old than young adults. Results demonstrated that the robust age-related decline in P3b amplitude to visual targets disappeared after controlling for visual acuity, but was unaffected by accounting for auditory acuity. Path analysis confirmed that the relationship between age and diminished P3b to visual targets was mediated by visual acuity, suggesting that conveyance of suboptimal sensory data due to peripheral, rather than central, deficits may undermine subsequent neural processing. We conclude that until the relationship between age-associated differences in visual acuity and neural activity during experimental tasks is clearly established, investigators should exercise caution attributing results to differences in cognitive processing. PMID:26825439

  1. Visual-based quadrotor control by means of fuzzy cognitive maps.

    Science.gov (United States)

    Amirkhani, Abdollah; Shirzadeh, Masoud; Papageorgiou, Elpiniki I; Mosavi, Mohammad R

    2016-01-01

    By applying an image-based visual servoing (IBVS) method, the intelligent image-based controlling of a quadrotor type unmanned aerial vehicle (UAV) tracking a moving target is studied in this paper. A fuzzy cognitive map (FCM) is a soft computing method which is classified as a fuzzy neural system and exploits the main aspects of fuzzy logic and neural network systems; so it seems to be a suitable choice for implementing a vision-based intelligent technique. An FCM has been employed in implementing an IBVS scheme on a quadrotor UAV, so that the UAV can track a moving target on the ground. For this purpose, by properly combining the perspective image moments, some features with the desired characteristics for controlling the translational and yaw motions of a UAV have been presented. In designing a vision-based control method for a UAV quadrotor, there are some challenges, including the target mobility and not knowing the height of UAV above the target. Also, no sensor has been installed on the moving object and the changes of its yaw angle are not available. Despite all the stated challenges, the proposed method, which uses an FCM in controlling the translational motion and the yaw rotation of a UAV, adequately enables the quadrotor to follow the moving target. The simulation results for different paths show the satisfactory performance of the designed controller. PMID:26678850

  2. Cell shape regulation through mechanosensory feedback control.

    Science.gov (United States)

    Mohan, Krithika; Luo, Tianzhi; Robinson, Douglas N; Iglesias, Pablo A

    2015-08-01

    Cells undergo controlled changes in morphology in response to intracellular and extracellular signals. These changes require a means for sensing and interpreting the signalling cues, for generating the forces that act on the cell's physical material, and a control system to regulate this process. Experiments on Dictyostelium amoebae have shown that force-generating proteins can localize in response to external mechanical perturbations. This mechanosensing, and the ensuing mechanical feedback, plays an important role in minimizing the effect of mechanical disturbances in the course of changes in cell shape, especially during cell division, and likely in other contexts, such as during three-dimensional migration. Owing to the complexity of the feedback system, which couples mechanical and biochemical signals involved in shape regulation, theoretical approaches can guide further investigation by providing insights that are difficult to decipher experimentally. Here, we present a computational model that explains the different mechanosensory and mechanoresponsive behaviours observed in Dictyostelium cells. The model features a multiscale description of myosin II bipolar thick filament assembly that includes cooperative and force-dependent myosin-actin binding, and identifies the feedback mechanisms hidden in the observed mechanoresponsive behaviours of Dictyostelium cells during micropipette aspiration experiments. These feedbacks provide a mechanistic explanation of cellular retraction and hence cell shape regulation. PMID:26224568

  3. Wnt signaling and stem cell control

    Institute of Scientific and Technical Information of China (English)

    Roel Nusse

    2008-01-01

    Wnt signaling has been implicated in the control over various types of stem cells and may act as a niche factor to maintain stem cells in a self-renewing state.As currently understood,Wnt proteins bind to receptors of the Frizzled and LRP families on the cell surface.Through several cytoplasmic relay components,the signal is transduced to B-catenin,which then enters the nucleus and forms a complex with TCF to activate transcription of Wnt target genes.Wnts can also signal through tyrosine kinase receptors,in particular the ROR and RYK receptors,leading to alternative modes of Wnt signaling.During the growth of tissues,these ligands and receptors are dynamically expressed,often transcriptionally controlled by Wnt signals themselves,to ensure the right balance between proliferation and differentiation.Isolated Wnt proteins are active on a variety of stem cells,including neural,mammary and embryonic stem cells.In general,Wnt proteins act to maintain the undifferentiated state of stem cells,while other growth factors instruct the cells to proliferate.These other factors include FGF and EGF,signaling through tyrosine kinase pathways.

  4. Regulating outdoor advertisement boards; employing spatial decision support system to control urban visual pollution

    Science.gov (United States)

    Wakil, K.; Hussnain, MQ; Tahir, A.; Naeem, M. A.

    2016-06-01

    Unmanaged placement, size, location, structure and contents of outdoor advertisement boards have resulted in severe urban visual pollution and deterioration of the socio-physical living environment in urban centres of Pakistan. As per the regulatory instruments, the approval decision for a new advertisement installation is supposed to be based on the locational density of existing boards and their proximity or remoteness to certain land- uses. In cities, where regulatory tools for the control of advertisement boards exist, responsible authorities are handicapped in effective implementation due to the absence of geospatial analysis capacity. This study presents the development of a spatial decision support system (SDSS) for regularization of advertisement boards in terms of their location and placement. The knowledge module of the proposed SDSS is based on provisions and restrictions prescribed in regulatory documents. While the user interface allows visualization and scenario evaluation to understand if the new board will affect existing linear density on a particular road and if it violates any buffer restrictions around a particular land use. Technically the structure of the proposed SDSS is a web-based solution which includes open geospatial tools such as OpenGeo Suite, GeoExt, PostgreSQL, and PHP. It uses three key data sets including road network, locations of existing billboards and building parcels with land use information to perform the analysis. Locational suitability has been calculated using pairwise comparison through analytical hierarchy process (AHP) and weighted linear combination (WLC). Our results indicate that open geospatial tools can be helpful in developing an SDSS which can assist solving space related iterative decision challenges on outdoor advertisements. Employing such a system will result in effective implementation of regulations resulting in visual harmony and aesthetic improvement in urban communities.

  5. A comparison of kinesthetic-tactual and visual displays via a critical tracking task. [for aircraft control

    Science.gov (United States)

    Jagacinski, R. J.; Miller, D. P.; Gilson, R. D.

    1979-01-01

    The feasibility of using the critical tracking task to evaluate kinesthetic-tactual displays was examined. The test subjects were asked to control a first-order unstable system with a continuously decreasing time constant by using either visual or tactual unidimensional displays. The results indicate that the critical tracking task is both a feasible and a reliable methodology for assessing tactual tracking. Further, that the critical tracking methodology is as sensitive and valid a measure of tactual tracking as visual tracking is demonstrated by the approximately equal effects of quickening for the tactual and visual displays.

  6. Adaptive control of nonlinear visual servoing systems for 3D cartesian tracking

    Directory of Open Access Journals (Sweden)

    Alessandro R. L. Zachi

    2006-12-01

    Full Text Available This paper presents a control strategy for robot manipulators to perform 3D cartesian tracking using visual servoing. Considering a fixed camera, the 3D cartesian motion is decomposed in a 2D motion on a plane orthogonal to the optical axis and a 1D motion parallel to this axis. An image-based visual servoing approach is used to deal with the nonlinear control problem generated by the depth variation without requiring direct depth estimation. Due to the lack of camera calibration, an adaptive control method is used to ensure both depth and planar tracking in the image frame. The depth feedback loop is closed by measuring the image area of a target object attached to the robot end-effector. Simulation and experimental results obtained with a real robot manipulator illustrate the viability of the proposed scheme.Este trabalho apresenta uma estratégia de controle para robôs manipuladores realizarem rastreamento cartesiano 3D utilizando servovisão. Considerando uma câmera fixa, o movimento cartesiano 3D é decomposto em um movimento 2D sobre um plano ortogonal ao eixo óptico e em outro movimento 1D paralelo ao mesmo eixo. Uma abordagem de servovisão baseada em imagem é utilizada para tratar o problema de controle não-linear, gerado pela variação de profundidade, sem a necessidade de estimar esta medida. Devido à ausência de calibração da câmera, um método de controle adaptativo é utilizado para assegurar rastreamento planar e de profundidade nas coordenadas da imagem. A malha de controle de profundidade é fechada através da medição da área da imagem de um objeto fixado no efetuador do robô. Simulação e resultados experimentais, obtidos com um robô manipulador real, ilustram a viabilidade do esquema proposto.

  7. Bacterial cell curvature through mechanical control of cell growth

    DEFF Research Database (Denmark)

    Cabeen, M.; Charbon, Godefroid; Vollmer, W.;

    2009-01-01

    The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure that coll...... cell wall insertion to produce curved growth. Our study suggests that bacteria may use the cytoskeleton for mechanical control of growth to alter morphology......The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure that...

  8. Visual working memory capacity increases between ages 3 and 8 years, controlling for gains in attention, perception, and executive control.

    Science.gov (United States)

    Pailian, Hrag; Libertus, Melissa E; Feigenson, Lisa; Halberda, Justin

    2016-08-01

    Research in adults has aimed to characterize constraints on the capacity of Visual Working Memory (VWM), in part because of the system's broader impacts throughout cognition. However, less is known about how VWM develops in childhood. Existing work has reached conflicting conclusions as to whether VWM storage capacity increases after infancy, and if so, when and by how much. One challenge is that previous studies did not control for developmental changes in attention and executive processing, which also may undergo improvement. We investigated the development of VWM storage capacity in children from 3 to 8 years of age, and in adults, while controlling for developmental change in exogenous and endogenous attention and executive control. Our results reveal that, when controlling for improvements in these abilities, VWM storage capacity increases across development and approaches adult-like levels between ages 6 and 8 years. More generally, this work highlights the value of estimating working memory, attention, perception, and decision-making components together. PMID:27225467

  9. Visualization of Fuel Cell Water Transport and Performance Characterization under Freezing Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kandlikar, S.G.; Lu, Z.; Rao, N.; Sergi, J.; Rath, C.; Dade, C.; Trabold, T.; Owejan, J.; Gagliardo, J.; Allen, J.; Yassar, R.S.; Medici, E.; Herescu, A.

    2010-05-30

    In this program, Rochester Institute of Technology (RIT), General Motors (GM) and Michigan Technological University (MTU) have focused on fundamental studies that address water transport, accumulation and mitigation processes in the gas diffusion layer and flow field channels of the bipolar plate. These studies have been conducted with a particular emphasis on understanding the key transport phenomena which control fuel cell operation under freezing conditions. Technical accomplishments are listed below: • Demonstrated that shutdown air purge is controlled predominantly by the water carrying capacity of the purge stream and the most practical means of reducing the purge time and energy is to reduce the volume of liquid water present in the fuel cell at shutdown. The GDL thermal conductivity has been identified as an important parameter to dictate water accumulation within a GDL. • Found that under the normal shutdown conditions most of the GDL-level water accumulation occurs on the anode side and that the mass transport resistance of the membrane electrode assembly (MEA) thus plays a critically important role in understanding and optimizing purge. • Identified two-phase flow patterns (slug, film and mist flow) in flow field channel, established the features of each pattern, and created a flow pattern map to characterize the two-phase flow in GDL/channel combination. • Implemented changes to the baseline channel surface energy and GDL materials and evaluated their performance with the ex situ multi-channel experiments. It was found that the hydrophilic channel (contact angle   10⁰) facilitates the removal of liquid water by capillary effects and by reducing water accumulation at the channel exit. It was also found that GDL without MPL promotes film flow and shifts the slug-to-film flow transition to lower air flow rates, compared with the case of GDL with MPL. • Identified a new mechanism of water transport through GDLs based on Haines jump

  10. Plataforma de desarrollo para el control en tiempo real de estructuras cinemáticas con realimentación visual//Platform to develop real time visual servoing control in kinematics systems

    Directory of Open Access Journals (Sweden)

    René González-Rodríguez

    2012-09-01

    Full Text Available En este trabajo se presenta una plataforma de desarrollo para el control en tiempo real de estructuras cinemáticas con realimentación visual. Se ha diseñado una configuración genérica que permite la implementación de cualquier variante de control visual. Para el procesamiento de la imagen se ha propuesto una estrategia que permite el uso de diferentes herramientas comerciales o algoritmos propiospara la captura y extracción de características de la imagen. El uso de Real Time Work Shop y Real Time Windows Target en el lazo de control interno brinda la posibilidad de implementar algoritmos de control servovisual en tiempo real. Al final del trabajo se presentan los resultados de un esquema de controlservovisual aplicado en un manipulador industrial. La plataforma propuesta constituye una herramienta de desarrollo para aplicaciones industriales de control servovisual y sirve de apoyo a la enseñanza de la mecatrónica en pregrado y postgrado.Palabras claves: control servovisual, control en tiempo real, estructuras cinemáticas._______________________________________________________________________________AbstractIn this work we propose a platform to develop visual servoing control systems. The platform has a generic design with the possibility to implement direct or look and move visual servoing systems. For the image processing we present a generic design allowing the use of any image processing library like Matrox MIL,Intel IPP, OpenCV or any algorithms for image capture and target characteristics extraction. The uses of Real Time Work Shop and Real Time Windows Target in the internal loop permits modify the control structure in SIMULINK very easy.Key words: visual servoing, real time control, kinematics systems.

  11. Teneurin-3 Specifies Morphological and Functional Connectivity of Retinal Ganglion Cells in the Vertebrate Visual System

    Directory of Open Access Journals (Sweden)

    Paride Antinucci

    2013-11-01

    Full Text Available A striking feature of the CNS is the precise wiring of its neuronal connections. During vertebrate visual system development, different subtypes of retinal ganglion cells (RGCs form specific connections with their corresponding synaptic partners. However, the underlying molecular mechanisms remain to be fully elucidated. Here, we report that the cell-adhesive transmembrane protein Teneurin-3 (Tenm3 is required by zebrafish RGCs for acquisition of their correct morphological and functional connectivity in vivo. Teneurin-3 is expressed by RGCs and their presynaptic amacrine and postsynaptic tectal cell targets. Knockdown of Teneurin-3 leads to RGC dendrite stratification defects within the inner plexiform layer, as well as mistargeting of dendritic processes into outer portions of the retina. Moreover, a subset of RGC axons exhibits tectal laminar arborization errors. Finally, functional analysis of RGCs targeting the tectum reveals a selective deficit in the development of orientation selectivity after Teneurin-3 knockdown. These results suggest that Teneurin-3 plays an instructive role in the functional wiring of the vertebrate visual system.

  12. Quality control in diagnostic radiology: software (Visual Basic 6) and database applications

    International Nuclear Information System (INIS)

    Quality Assurance programme in diagnostic Radiology is being implemented by the Ministry of Health (MoH) in Malaysia. Under this program the performance of an x-ray machine used for diagnostic purpose is tested by using the approved procedure which is commonly known as Quality Control in diagnostic radiology. The quality control or performance tests are carried out b a class H licence holder issued the Atomic Energy Licensing Act 1984. There are a few computer applications (software) that are available in the market which can be used for this purpose. A computer application (software) using Visual Basics 6 and Microsoft Access, is being developed to expedite data handling, analysis and storage as well as report writing of the quality control tests. In this paper important features of the software for quality control tests are explained in brief. A simple database is being established for this purpose which is linked to the software. Problems encountered in the preparation of database are discussed in this paper. A few examples of practical usage of the software and database applications are presented in brief. (Author)

  13. Visualized Multiprobe Electrical Impedance Measurements with STM Tips Using Shear Force Feedback Control

    Directory of Open Access Journals (Sweden)

    Luis Botaya

    2016-05-01

    Full Text Available Here we devise a multiprobe electrical measurement system based on quartz tuning forks (QTFs and metallic tips capable of having full 3D control over the position of the probes. The system is based on the use of bent tungsten tips that are placed in mechanical contact (glue-free solution with a QTF sensor. Shear forces acting in the probe are measured to control the tip-sample distance in the Z direction. Moreover, the tilting of the tip allows the visualization of the experiment under the optical microscope, allowing the coordination of the probes in X and Y directions. Meanwhile, the metallic tips are connected to a current–voltage amplifier circuit to measure the currents and thus the impedance of the studied samples. We discuss here the different aspects that must be addressed when conducting these multiprobe experiments, such as the amplitude of oscillation, shear force distance control, and wire tilting. Different results obtained in the measurement of calibration samples and microparticles are presented. They demonstrate the feasibility of the system to measure the impedance of the samples with a full 3D control on the position of the nanotips.

  14. Control of apoptosis by asymmetric cell division.

    Science.gov (United States)

    Hatzold, Julia; Conradt, Barbara

    2008-04-01

    Asymmetric cell division and apoptosis (programmed cell death) are two fundamental processes that are important for the development and function of multicellular organisms. We have found that the processes of asymmetric cell division and apoptosis can be functionally linked. Specifically, we show that asymmetric cell division in the nematode Caenorhabditis elegans is mediated by a pathway involving three genes, dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail, that directly control the enzymatic machinery responsible for apoptosis. Interestingly, the MIDA1-like protein GlsA of the alga Volvox carteri, as well as the Snail-related proteins Snail, Escargot, and Worniu of Drosophila melanogaster, have previously been implicated in asymmetric cell division. Therefore, C. elegans dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail may be components of a pathway involved in asymmetric cell division that is conserved throughout the plant and animal kingdoms. Furthermore, based on our results, we propose that this pathway directly controls the apoptotic fate in C. elegans, and possibly other animals as well. PMID:18399720

  15. Visual appearance and CMT score of foremilk of individual quarters in relation to cell count of cows milked automatically.

    Science.gov (United States)

    Rasmussen, Morten D; Bjerring, Martin; Skjøth, Flemming

    2005-02-01

    The objectives of the study were: to evaluate the interaction between visual appearance and California mastitis test (CMT) score of the foremilk in relation to the cell count of the milk; to evaluate the consequences of sorting milk according to these criteria; and to explore whether visual appearance and CMT score of foremilk depended on the time interval between milkings. Measuring somatic cell count (SCC) in composite milk only and discarding milk above certain thresholds will not ensure that milk from all cows with visually abnormal foremilk is withheld from delivery. Low thresholds of SCC will reduce the frequency of cows with abnormal milk but increase the discarding of milk from cows with visually normal foremilk. CMT score of foremilk differentiated better between cows with high and low SCC in composite milk than visual inspection of foremilk. CMT scores of foremilk decreased with increasing interval between milkings within cow, whereas the visual appearance was independent of the interval. We propose that visual appearance of the foremilk should be kept as a criterion for sorting milk at time of milking. For test purposes, the use of visual appearance of foremilk for differentiation between normal and abnormal milk has to be done on multiple milkings. Additionally, CMT scoring of foremilk improves correct classification of normal and abnormal quarters and especially when including data from the previous milking. PMID:15747731

  16. Demonstration of a visual cell-based assay for screening glucose transporter 4 translocation modulators in real time

    Indian Academy of Sciences (India)

    Maleppillil Vavachan Vijayakumar; Amrendra Kumar Ajay; Manoj Kumar Bhat

    2010-12-01

    Insulin-stimulated translocation of glucose transporter 4 (GLUT4) to cell membrane leading to glucose uptake is the rate-limiting step in diabetes. It is also a defined target of antidiabetic drug research. Existing GLUT4 translocation assays are based on time-consuming immunoassays and are hampered by assay variability and low sensitivity. We describe a real-time, visual, cell-based qualitative GLUT4 translocation assay using CHO-HIRc-myc-GLUT4eGFP cells that stably express myc- and eGFP-tagged GLUT4 in addition to human insulin receptor (HIRc). GLUT4 translocation is visualized by live cell imaging based on GFP fluorescence by employing a cooled charge-coupled device camera attached to a fluorescent microscope. This video imaging method and further quantitative analysis of GLUT4 on the cell membrane provide rapid and foolproof visual evidence that this method is suitable for screening GLUT4 translocation modulators.

  17. Inverting adherent cells for visualizing ECM interactions at the basal cell side

    International Nuclear Information System (INIS)

    Interactions with the extracellular matrix (ECM) govern a wide range of cellular functions, including survival, migration and invasion. However, in adherent cells these interactions occur primarily on the basal cell side, making them inaccessible to high-resolution, surface-scanning imaging techniques such as atomic force microscopy (AFM) or scanning electron microscopy (SEM). Here we describe a fast and reliable method for inverting adherent cells, exposing the basal cell membrane for direct analysis by AFM or SEM in combination with fluorescence microscopy. Cells including their matrix adhesion sites remain intact during the inversion process and are transferred together with the complete array of basally associated ECM proteins. Molecular features of ECM proteins, such as the characteristic 67 nm collagen D-periodicity, are well preserved after inversion. To demonstrate the versatility of the method, we compared basal interactions of fibroblasts with fibrillar collagen I and fibronectin matrices. While fibroblasts remodel the fibronectin layer exclusively from above, they actively invade even thin collagen layers by contacting individual collagen nanofibrils both basally and apically through a network of cellular extensions. Cell–matrix entanglement coincides with enhanced cell spreading and flattening, indicating that nanoscale ECM interactions govern macroscopic changes in cell morphology. The presented cell inversion technique can thus provide novel insight into nanoscale cell–matrix interactions at the basal cell side. - Highlights: ► We present a novel method for inverting adherent cells to expose the basal cell side. ► Basal cell sides can be imaged at high resolution by AFM and SEM. ► Cells can be inverted together with the underlying extracellular matrix. ► AFM images of inverted cells provide a nanoscale look at basal cell–ECM interactions

  18. A system and methodology for high-content visual screening of individual intact living cells in suspension

    Science.gov (United States)

    Renaud, Olivier; Heintzmann, Rainer; Sáez-Cirión, Asier; Schnelle, Thomas; Mueller, Torsten; Shorte, Spencer

    2007-02-01

    Three dimensional imaging provides high-content information from living intact biology, and can serve as a visual screening cue. In the case of single cell imaging the current state of the art uses so-called "axial through-stacking". However, three-dimensional axial through-stacking requires that the object (i.e. a living cell) be adherently stabilized on an optically transparent surface, usually glass; evidently precluding use of cells in suspension. Aiming to overcome this limitation we present here the utility of dielectric field trapping of single cells in three-dimensional electrode cages. Our approach allows gentle and precise spatial orientation and vectored rotation of living, non-adherent cells in fluid suspension. Using various modes of widefield, and confocal microscope imaging we show how so-called "microrotation" can provide a unique and powerful method for multiple point-of-view (three-dimensional) interrogation of intact living biological micro-objects (e.g. single-cells, cell aggregates, and embryos). Further, we show how visual screening by micro-rotation imaging can be combined with micro-fluidic sorting, allowing selection of rare phenotype targets from small populations of cells in suspension, and subsequent one-step single cell cloning (with high-viability). Our methodology combining high-content 3D visual screening with one-step single cell cloning, will impact diverse paradigms, for example cytological and cytogenetic analysis on haematopoietic stem cells, blood cells including lymphocytes, and cancer cells.

  19. Hierarchical structural control of visual properties in self-assembled photonic-plasmonic pigments

    CERN Document Server

    Koay, Natalie; Kay, Theresa M; Nerger, Bryan A; Miles-Rossouw, Malaika; Shirman, Tanya; Vu, Thy L; England, Grant; Phillips, Katherine R; Utech, Stefanie; Vogel, Nicolas; Kolle, Mathias; Aizenberg, Joanna

    2014-01-01

    We present a simple one-pot co-assembly method for the synthesis of hierarchically structured pigment particles consisting of silica inverse-opal bricks that are doped with plasmonic absorbers. We study the interplay between the plasmonic and photonic resonances and their effect on the visual appearance of macroscopic collections of photonic bricks that are distributed in randomized orientations. Manipulating the pore geometry tunes the wavelength- and angle-dependence of the scattering profile, which can be engineered to produce angle-dependent Bragg resonances that can either enhance or contrast with the color produced by the plasmonic absorber. By controlling the overall dimensions of the photonic bricks and their aspect ratios, their preferential alignment can either be encouraged or suppressed. This causes the Bragg resonance to appear either as uniform color travel in the former case or as sparse iridescent sparkle in the later case. By manipulating the surface chemistry of these photonic bricks, which ...

  20. Can Dynamic Visualizations with Variable Control Enhance the Acquisition of Intuitive Knowledge?

    Science.gov (United States)

    Wichmann, Astrid; Timpe, Sebastian

    2015-10-01

    An important feature of inquiry learning is to take part in science practices including exploring variables and testing hypotheses. Computer-based dynamic visualizations have the potential to open up various exploration possibilities depending on the level of learner control. It is assumed that variable control, e.g., by changing parameters of a variable, leads to deeper processing (Chang and Linn 2013; de Jong and Njoo 1992; Nerdel 2003; Trey and Khan 2008). Variable control may be helpful, in particular, for acquiring intuitive knowledge (Swaak and de Jong 2001). However, it bares the risk of mental exhaustion and thus may have detrimental effects on knowledge acquisition (Sweller 1998). Students ( N = 118) from four chemistry classes followed inquiry cycles using the software Molecular Workbench (Xie and Tinker 2006). Variable control was varied across the conditions (1) No-Manipulation group and (2) Manipulation group. By adding a third condition, (3) Manipulation-Plus group, we tested whether adding an active hypothesis phase prepares students before changing parameters of a variable. As expected, students in the Manipulation group and Manipulation-Plus group performed better concerning intuitive knowledge ( d = 1.14) than students in the No-Manipulation group. On a descriptive level, results indicated higher cognitive effort in the Manipulation group and the Manipulation-Plus group than in the No-Manipulation group. Unexpectedly, students in the Manipulation-Plus group did not benefit from the active hypothesis phase (intuitive knowledge: d = .36). Findings show that students benefit from variable control. Furthermore, findings point toward the direction that variable control evokes desirable difficulties (Bjork and Linn 2006).

  1. Plataforma de desarrollo para el control en tiempo real de estructuras cinemáticas con realimentación visual//Platform to develop real time visual servoing control in kinematics systems

    OpenAIRE

    René González-Rodríguez; Luis Hernández-Santana

    2012-01-01

    En este trabajo se presenta una plataforma de desarrollo para el control en tiempo real de estructuras cinemáticas con realimentación visual. Se ha diseñado una configuración genérica que permite la implementación de cualquier variante de control visual. Para el procesamiento de la imagen se ha propuesto una estrategia que permite el uso de diferentes herramientas comerciales o algoritmos propiospara la captura y extracción de características de la imagen. El uso de Real Time Work Shop y Real...

  2. Visualization of N-acylhomoserine lactone-mediated cell-cell communication between bacteria colonizing the tomato rhizosphere

    DEFF Research Database (Denmark)

    Steidle, A.; Sigl, K.; Schuhegger, R.;

    2001-01-01

    developed and characterized novel Gfp-based monitor strains that allow in situ visualization of AHL-mediated communication between individual cells in the plant rhizosphere. For this purpose, three Gfp-based AHL sensor plasmids that respond to different spectra of AHL molecules were transferred into AHL...... into the chromosome of AHL-negative P. putida strain F117 an AHL sensor cassette that responds to the presence of long-chain AHLs with the expression of Gfp. This monitor strain was used to demonstrate that the indigenous bacterial community colonizing the roots of tomato plants growing in nonsterile soil produces...

  3. A Multi-technique GIS Visibility Analysis for Studying Visual Control of an Iron Age Landscape

    Directory of Open Access Journals (Sweden)

    Carme Rueses Bitrià

    2008-03-01

    Full Text Available This article proposes a multi-technique GIS (Geographical Information System approach to visibility analysis intended to address some of the shortcomings of the traditional binary viewshed. Its ultimate aim is to obtain more accurate viewsheds and, thus, gain more robust archaeological conclusions from their analysis and interpretation. Composite image showing viewsheds of study area A number of methods have been put forward to overcome the limitations of traditional binary viewsheds (e.g. Wheatley and Gillings 2000. However, the majority of practical applications, based upon binary viewsheds, tend to concentrate on only one of several methodological issues that affect the accuracy of viewsheds (e.g. multiple viewer points. At best, this can lead to flawed archaeological interpretations. The enriched methodological protocol presented here combines a variety of procedures in an effort to obtain viewsheds that offer a more complete and accurate delineation of visible areas while explicitly acknowledging the reduction in visual clarity with increasing distance. The approach advocates the use of multiple viewer points coupled with 'probable' viewsheds i.e. viewsheds that are sensitive to the errors inherent to the DEM used to generate them. The result is a 'most probable' viewshed that can be carried forward for more structured investigation such as 'Higuchi' and 'cumulative' analyses. This method is used to investigate visibility from the Iberian hillforts that dominated the landscape surrounding Badalona (north of Barcelona, Catalonia, Spain during the 3rd century BC. The study of visual control from the hillforts is understood as a means to deal with notions of social structure and hierarchy. Visibility analysis indicates a highly structured society, where each hillfort might have primarily controlled given zones of the landscape and might have informed others through an integrated visibility network about events taking place there.

  4. Effects of Anodal Transcranial Direct Current Stimulation on Visually Guided Learning of Grip Force Control

    Directory of Open Access Journals (Sweden)

    Tamas Minarik

    2015-03-01

    Full Text Available Anodal transcranial Direct Current Stimulation (tDCS has been shown to be an effective non-invasive brain stimulation method for improving cognitive and motor functioning in patients with neurological deficits. tDCS over motor cortex (M1, for instance, facilitates motor learning in stroke patients. However, the literature on anodal tDCS effects on motor learning in healthy participants is inconclusive, and the effects of tDCS on visuo-motor integration are not well understood. In the present study we examined whether tDCS over the contralateral motor cortex enhances learning of grip-force output in a visually guided feedback task in young and neurologically healthy volunteers. Twenty minutes of 1 mA anodal tDCS were applied over the primary motor cortex (M1 contralateral to the dominant (right hand, during the first half of a 40 min power-grip task. This task required the control of a visual signal by modulating the strength of the power-grip for six seconds per trial. Each participant completed a two-session sham-controlled crossover protocol. The stimulation conditions were counterbalanced across participants and the sessions were one week apart. Performance measures comprised time-on-target and target-deviation, and were calculated for the periods of stimulation (or sham and during the afterphase respectively. Statistical analyses revealed significant performance improvements over the stimulation and the afterphase, but this learning effect was not modulated by tDCS condition. This suggests that the form of visuomotor learning taking place in the present task was not sensitive to neurostimulation. These null effects, together with similar reports for other types of motor tasks, lead to the proposition that tDCS facilitation of motor learning might be restricted to cases or situations where the motor system is challenged, such as motor deficits, advanced age, or very high task demand.

  5. Reciprocal control of cell proliferation and migration

    Directory of Open Access Journals (Sweden)

    De Donatis Alina

    2010-09-01

    Full Text Available Abstract In adult tissue the quiescent state of a single cell is maintained by the steady state conditions of its own microenvironment for what concern both cell-cell as well as cell-ECM interaction and soluble factors concentration. Physiological or pathological conditions can alter this quiescent state through an imbalance of both soluble and insoluble factors that can trigger a cellular phenotypic response. The kind of cellular response depends by many factors but one of the most important is the concentration of soluble cytokines sensed by the target cell. In addition, due to the intrinsic plasticity of many cellular types, every single cell is able, in response to the same stimulus, to rapidly switch phenotype supporting minimal changes of microenviromental cytokines concentration. Wound healing is a typical condition in which epithelial, endothelial as well as mesenchymal cells are firstly subjected to activation of their motility in order to repopulate the damaged region and then they show a strong proliferative response in order to successfully complete the wound repair process. This schema constitute the leitmotif of many other physiological or pathological conditions such as development vasculogenesis/angiogenesis as well as cancer outgrowth and metastasis. Our review focuses on the molecular mechanisms that control the starting and, eventually, the switching of cellular phenotypic outcome in response to changes in the symmetry of the extracellular environment.

  6. Electric field control of the cell orientation

    Science.gov (United States)

    Westman, Christopher; Sabirianov, Renat

    2008-03-01

    Many physiological processes depend on the response of biological cells to external forces. The natural electric field at a wound controls the orientation of the cell and its division.[1] We model the cell as an elongated elliptical particle with given Young's modulus with surface charge distribution in the external electric field. Using this simple theoretical model that includes the forces due to electrostatics and the elasticity of cells, we calculated analytically the response of the cell orientation and its dynamics in the presence of time varying electric field. The calculations reflect many experimentally observed features. Our model predicts the response of the cellular orientation to a sinusoidally varying applied electric field as a function of frequency similar to recent stress-induced effects.[2] *Bing Song, Min Zhao, John V. Forrester, and Colin D. McCaig, ``Electrical cues regulate the orientation and frequency of cell division and the rate of wound healing in vivo'', PNAS 2002, vol. 99 , 13577-13582. *R. De, A. Zemel, and S.A. Safran, ``Dynamics of cell orientation'', Nature Physics 2007, vol.3, 655.

  7. Specific visualization of glioma cells in living low-grade tumor tissue.

    Directory of Open Access Journals (Sweden)

    Sven R Kantelhardt

    Full Text Available BACKGROUND: The current therapy of malignant gliomas is based on surgical resection, radio-chemotherapy and chemotherapy. Recent retrospective case-series have highlighted the significance of the extent of resection as a prognostic factor predicting the course of the disease. Complete resection in low-grade gliomas that show no MRI-enhanced images are especially difficult. The aim in this study was to develop a robust, specific, new fluorescent probe for glioma cells that is easy to apply to live tumor biopsies and could identify tumor cells from normal brain cells at all levels of magnification. METHODOLOGY/PRINCIPAL FINDINGS: In this investigation we employed brightly fluorescent, photostable quantum dots (QDs to specifically target epidermal growth factor receptor (EGFR that is upregulated in many gliomas. Living glioma and normal cells or tissue biopsies were incubated with QDs coupled to EGF and/or monoclonal antibodies against EGFR for 30 minutes, washed and imaged. The data include results from cell-culture, animal model and ex vivo human tumor biopsies of both low-grade and high-grade gliomas and show high probe specificity. Tumor cells could be visualized from the macroscopic to single cell level with contrast ratios as high as 1000: 1 compared to normal brain tissue. CONCLUSIONS/SIGNIFICANCE: The ability of the targeted probes to clearly distinguish tumor cells in low-grade tumor biopsies, where no enhanced MRI image was obtained, demonstrates the great potential of the method. We propose that future application of specifically targeted fluorescent particles during surgery could allow intraoperative guidance for the removal of residual tumor cells from the resection cavity and thus increase patient survival.

  8. Feedback and Modularity in Cell Cycle Control

    Science.gov (United States)

    Skotheim, Jan

    2009-03-01

    Underlying the wonderful diversity of natural forms is the ability of an organism to grow into its appropriate shape. Regulation ensures that cells grow, divide and differentiate so that the organism and its constitutive parts are properly proportioned and of suitable size. Although the size-control mechanism active in an individual cell is of fundamental importance to this process, it is difficult to isolate and study in complex multi-cellular systems and remains poorly understood. This motivates our use of the budding yeast model organism, whose Start checkpoint integrates multiple internal (e.g. cell size) and external signals into an irreversible decision to enter the cell cycle. We have endeavored to address the following two questions: What makes the Start transition irreversible? How does a cell compute its own size? I will report on the progress we have made. Our work is part of an emerging framework for understanding biological control circuits, which will allow us to discern the function of natural systems and aid us in engineering synthetic systems.

  9. Trained eyes: experience promotes adaptive gaze control in dynamic and uncertain visual environments.

    Directory of Open Access Journals (Sweden)

    Shuichiro Taya

    Full Text Available Current eye-tracking research suggests that our eyes make anticipatory movements to a location that is relevant for a forthcoming task. Moreover, there is evidence to suggest that with more practice anticipatory gaze control can improve. However, these findings are largely limited to situations where participants are actively engaged in a task. We ask: does experience modulate anticipative gaze control while passively observing a visual scene? To tackle this we tested people with varying degrees of experience of tennis, in order to uncover potential associations between experience and eye movement behaviour while they watched tennis videos. The number, size, and accuracy of saccades (rapid eye-movements made around 'events,' which is critical for the scene context (i.e. hit and bounce were analysed. Overall, we found that experience improved anticipatory eye-movements while watching tennis clips. In general, those with extensive experience showed greater accuracy of saccades to upcoming event locations; this was particularly prevalent for events in the scene that carried high uncertainty (i.e. ball bounces. The results indicate that, even when passively observing, our gaze control system utilizes prior relevant knowledge in order to anticipate upcoming uncertain event locations.

  10. Live-cell visualization of excitation energy dynamics in chloroplast thylakoid structures.

    Science.gov (United States)

    Iwai, Masakazu; Yokono, Makio; Kurokawa, Kazuo; Ichihara, Akira; Nakano, Akihiko

    2016-01-01

    The intricate molecular processes underlying photosynthesis have long been studied using various analytic approaches. However, the three-dimensional (3D) dynamics of such photosynthetic processes remain unexplored due to technological limitations related to investigating intraorganellar mechanisms in vivo. By developing a system for high-speed 3D laser scanning confocal microscopy combined with high-sensitivity multiple-channel detection, we visualized excitation energy dynamics in thylakoid structures within chloroplasts of live Physcomitrella patens cells. Two distinct thylakoid structures in the chloroplast, namely the grana and stroma lamellae, were visualized three-dimensionally in live cells. The simultaneous detection of the shorter (than ~670 nm) and longer (than ~680 nm) wavelength regions of chlorophyll (Chl) fluorescence reveals different spatial characteristics-irregular and vertical structures, respectively. Spectroscopic analyses showed that the shorter and longer wavelength regions of Chl fluorescence are affected more by free light-harvesting antenna proteins and photosystem II supercomplexes, respectively. The high-speed 3D time-lapse imaging of the shorter and longer wavelength regions also reveals different structural dynamics-rapid and slow movements within 1.5 seconds, respectively. Such structural dynamics of the two wavelength regions of Chl fluorescence would indicate excitation energy dynamics between light-harvesting antenna proteins and photosystems, reflecting the energetically active nature of photosynthetic proteins in thylakoid membranes. PMID:27416900

  11. From Errors Treatment to Exceptions Treatment Regarding the Execution Control over Visual Basic Programs

    Directory of Open Access Journals (Sweden)

    Cristina Raluca POPESCU

    2008-01-01

    Full Text Available In order to comply with the quality standards and with the best practices, the execution of the professional programs must be rigorously controlled so that to avoid occurrence of unpredictable situations that might generate anomalies and could lead to computer blockage, forced termination of the execution and data loss. In traditional programming languages, including Visual Basic 6, the concept of error is extremely evolved. It is considered as error any situation in which the program fails to execute correctly, regardless if such anomaly is generated by a software or hardware cause. Nowadays the modern platforms, including VB.NET have introduced a new concept: exception. Unfortunately, perhaps by mistake, exception is assimilated by many IT specialists as an exceptional (extraordinary situation or a rare situation.We agree with the opinion of those IT specialists asserting that error is strictly dependant on the programmer, when he/she fails in correctly generating the application’s structures, whilst exception is a situation not fitting in the usual natural execution or as desired by the programmer or user, without meaning that it occurs more often or more rarely.Designing robust programs implies for such not to terminate abnormally or block, not even upon receiving improper parameters. Two aspects are referred to: the behavior regarding low level errors (caused by the operation system, memory allocation, reading/writing in files or hardware malfunctions and the reaction to the user’s errors, such as providing incorrect input data or incorrect use of operations in respect with their sequences. Notwithstanding what platform is used in designing the programs and regardless the controversy between the specialists, in order for the execution to be terminated under the program’s control, the commands that might generate anomalies and interruptions should be strictly monitored. Implicitly, the execution control

  12. Identification, control and visually-guided behavior for a model helicopter

    Science.gov (United States)

    Saripalli, Srikanth

    Research on unmanned aerial vehicles is motivated by applications where human intervention is impossible, risky or expensive e.g. hazardous material recovery, traffic monitoring, disaster relief support, military operations etc. Due to its vertical take-off, landing and hover capabilities, a helicopter is an attractive platform for such applications. There are significant challenges to building an autonomous robotic helicopter - these span the areas of system identification, low-level control, state estimation, and planning. Towards the goal of fully-autonomous helicopters this thesis makes the following contributions. A continuous-discrete extended Kalman filter has been developed that combines inertial data with GPS and compass data to provide estimates of the 6DOF state of the helicopter. Using this filter a model for the helicopter has been identified based on frequency response techniques. The model has been validated in flight tests on a small helicopter testbed (1.6 m rotor diameter) at speeds upto 5 m/s. Based on evidence from this model a decoupled low-level controller has been developed which is embedded in a control architecture suitable for visually-guided navigation. As a novel application, we show how such a controller can be used to perform trajectory following on the helicopter where the desired trajectories are typical spacecraft landing trajectories, and the only controls available are thrusters. This in effect, produces a low-cost testbed for testing spacecraft landing and hazard avoidance on a planetary surface. Finally, we develop and extensively experimentally characterize algorithms for vision-based autonomous landing, object tracking, and sensor deployment.

  13. Visualization of regulations to support design and quality control--a long-term study.

    Science.gov (United States)

    Blomé, Mikael

    2012-01-01

    The aim of the study was to visualize design regulations of furniture by means of interactive technology based on earlier studies and practical examples. The usage of the visualized regulations was evaluated on two occasions: at the start when the first set of regulations was presented, and after six years of usage of all regulations. The visualized regulations were the result of a design process involving experts and potential users in collaboration with IKEA of Sweden AB. The evaluations by the different users showed a very positive response to using visualized regulations. The participative approach, combining expertise in specific regulations with visualization of guidelines, resulted in clear presentations of important regulations, and great attitudes among the users. These kinds of visualizations have proved to be applicable in a variety of product areas at IKEA, with a potential for further dissemination. It is likely that the approaches to design and visualized regulations in this case study could function in other branches. PMID:22317126

  14. Postnatal development of layer III pyramidal cells in the primary visual, inferior temporal, and prefrontal cortices of the marmoset

    OpenAIRE

    Hirosato eAoi; Tomofumi eOga; Tetsuya eSasaki; Ichiro eFujita; Noritaka eIchinohe

    2013-01-01

    Abnormalities in the processes of the generation and/or pruning of dendritic spines have been implicated in several mental disorders including autism and schizophrenia. We have chosen to examine the common marmoset (Callithrix jacchus) as a primate model to explore the processes. As a first step, we studied the postnatal development of basal dendritic trees and spines of layer-III pyramidal cells in the primary visual sensory cortex (V1), a visual association cortex (inferior temporal area, T...

  15. Carbon nanotubes for stem cell control

    Directory of Open Access Journals (Sweden)

    David A. Stout

    2012-07-01

    Full Text Available In the past decade, two major advancements have transformed the world of tissue engineering and regenerative medicine—stem cells and carbon nano-dimensional materials. In the past, stem cell therapy seemed like it may present a cure for all medical ailments, but problems arose (i.e., immune system clearance, control of differentiation in the body, etc. that have hindered progress. But, with the synergy of carbon nano-dimensional materials, researchers have been able to overcome these tissue engineering and regenerative medicine obstacles and have begun developing treatments for strokes, bone failure, cardiovascular disease, and many other conditions. Here, we briefly review research involving carbon nanotubes which are relevant to the tissue engineering and regenerative medicine field with a special emphasis on carbon nanotube applications for stem cell delivery, drug delivery applications, and their use as improved medical devices.

  16. Role of polyphenols in cell death control.

    Science.gov (United States)

    Giovannini, Claudio; Masella, Roberta

    2012-05-01

    Dietary consumption of fruit, vegetables, fish, and olive oil has been demonstrated to exert beneficial effects on human health. This finding may be due to the high content of antioxidant compounds including polyphenols. Current evidence strongly supports a contribution of polyphenols to the prevention of several chronic degenerative diseases such as cancer, atherosclerosis and cardiovascular diseases, central nervous system disorders, as well as aging. Apoptosis is a genetically controlled and evolutionarily conserved form of cell death of critical importance for the maintenance of tissue homeostasis in the adult organism. The malfunction of the death machinery may play a primary role in various pathologic processes, leading to proliferative or degenerative diseases. Polyphenols can interact with specific steps and/or proteins regulating the apoptotic process in different ways depending on their concentration, the cell system, the type or stage of the pathological process. Because of their ability to modulate cell death, polyphenols have been proposed as chemopreventive and therapeutic agents. This paper reviews and discusses the last 3-year findings related to the principal molecular mechanisms involved in the control of the balance between apoptosis and cell proliferation exerted by polyphenols. PMID:22584012

  17. Visualization of the Nucleolus in Living Cells with Cell-Penetrating Fluorescent Peptides.

    Science.gov (United States)

    Martin, Robert M; Herce, Henry D; Ludwig, Anne K; Cardoso, M Cristina

    2016-01-01

    The nucleolus is the hallmark of nuclear compartmentalization and has been shown to exert multiple roles in cellular metabolism besides its main function as the place of ribosomal RNA synthesis and assembly of ribosomes. The nucleolus plays also a major role in nuclear organization as the largest compartment within the nucleus. The prominent structure of the nucleolus can be detected using contrast light microscopy providing an approximate localization of the nucleolus, but this approach does not allow to determine accurately the three-dimensional structure of the nucleolus in cells and tissues. Immunofluorescence staining with antibodies specific to nucleolar proteins albeit very useful is time consuming, normally antibodies recognize their epitopes only within a small range of species and is applicable only in fixed cells. Here, we present a simple method to selectively and accurately label this ubiquitous subnuclear compartment in living cells of a large range of species using a fluorescently labeled cell-penetrating peptide. PMID:27576711

  18. Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules.

    Science.gov (United States)

    Leinen, Philipp; Green, Matthew F B; Esat, Taner; Wagner, Christian; Tautz, F Stefan; Temirov, Ruslan

    2015-01-01

    Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM) is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM) introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926-1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf) of the non-contact atomic force microscope (NC-AFM) tuning fork sensor as well as the magnitude of the electric current (I) flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111) surface. PMID:26665087

  19. Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules

    Directory of Open Access Journals (Sweden)

    Philipp Leinen

    2015-11-01

    Full Text Available Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926–1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf of the non-contact atomic force microscope (NC-AFM tuning fork sensor as well as the magnitude of the electric current (I flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111 surface.

  20. Top-down Control of Visual Alpha Oscillations: Sources of Control Signals and Their Mechanisms of Action

    OpenAIRE

    Chao eWang; Rajasimhan eRajagovindan; Sahng-Min eHan; Mingzhou eDing

    2016-01-01

    Alpha oscillations (8 to 12 Hz) are thought to inversely correlate with cortical excitability. Goal-oriented modulation of alpha has been studied extensively. In visual spatial attention, alpha over the region of visual cortex corresponding to the attended location decreases, signifying increased excitability to facilitate the processing of impending stimuli. In contrast, in retention of verbal working memory, alpha over visual cortex increases, signifying decreased excitability to gate out s...

  1. Top-Down Control of Visual Alpha Oscillations: Sources of Control Signals and Their Mechanisms of Action

    OpenAIRE

    Wang, Chao; Rajagovindan, Rajasimhan; Han, Sahng-Min; Ding, Mingzhou

    2016-01-01

    Alpha oscillations (8–12 Hz) are thought to inversely correlate with cortical excitability. Goal-oriented modulation of alpha has been studied extensively. In visual spatial attention, alpha over the region of visual cortex corresponding to the attended location decreases, signifying increased excitability to facilitate the processing of impending stimuli. In contrast, in retention of verbal working memory, alpha over visual cortex increases, signifying decreased excitability to gate out stim...

  2. Can retinal ganglion cell dipoles seed iso-orientation domains in the visual cortex?

    Directory of Open Access Journals (Sweden)

    Manuel Schottdorf

    Full Text Available It has been argued that the emergence of roughly periodic orientation preference maps (OPMs in the primary visual cortex (V1 of carnivores and primates can be explained by a so-called statistical connectivity model. This model assumes that input to V1 neurons is dominated by feed-forward projections originating from a small set of retinal ganglion cells (RGCs. The typical spacing between adjacent cortical orientation columns preferring the same orientation then arises via Moiré-Interference between hexagonal ON/OFF RGC mosaics. While this Moiré-Interference critically depends on long-range hexagonal order within the RGC mosaics, a recent statistical analysis of RGC receptive field positions found no evidence for such long-range positional order. Hexagonal order may be only one of several ways to obtain spatially repetitive OPMs in the statistical connectivity model. Here, we investigate a more general requirement on the spatial structure of RGC mosaics that can seed the emergence of spatially repetitive cortical OPMs, namely that angular correlations between so-called RGC dipoles exhibit a spatial structure similar to that of OPM autocorrelation functions. Both in cat beta cell mosaics as well as primate parasol receptive field mosaics we find that RGC dipole angles are spatially uncorrelated. To help assess the level of these correlations, we introduce a novel point process that generates mosaics with realistic nearest neighbor statistics and a tunable degree of spatial correlations of dipole angles. Using this process, we show that given the size of available data sets, the presence of even weak angular correlations in the data is very unlikely. We conclude that the layout of ON/OFF ganglion cell mosaics lacks the spatial structure necessary to seed iso-orientation domains in the primary visual cortex.

  3. Control and optimization in fuel cell systems

    International Nuclear Information System (INIS)

    Fuel cells are electrochemical energy converters. They convert the chemical energy contained in the fuel into electricity while producing water and heat. Compared to the traditional energy converters, such as batteries and internal combustion engines, fuel cells are marked by high conversion efficiency and very low emissions.This work contains a computer study of optimization and control of fuel cells systems. An analytical study of the fuel (Hydrogen and air) supply system was performed taking into account compressor, cooling and humidification subsystems. In addition, the stack system, which consists of a lot of cells, was analyzed using the experimental equations of Nafion 117 membrane. The model of the whole system was then implemented in MATLAB/Simulink environment. The effect of the cathode pressure and the membrane water content on the polarization curves of the cell was examined. To validate the model, the responses of the model to step changes in the compressor voltage and the current drawn from the stack, were used. More attention was given to the net power which can be provided by the system, taking into account the power wasted by the compressor. (author)

  4. Modeling the Control of Planar Cell Polarity

    Science.gov (United States)

    Axelrod, Jeffrey D.; Tomlin, Claire J.

    2016-01-01

    A growing list of medically important developmental defects and disease mechanisms can be traced to disruption of the Planar Cell Polarity (PCP) pathway. The PCP system polarizes cells in epithelial sheets along an axis orthogonal to their apical-basal axis. Studies in the fruitfly, Drosophila, have led to the concept of a modular system controlling PCP. The components of the PCP signaling modules, and the effector systems with which they interact, function together to produce emergent patterns. Experimental methods allow the manipulation of individual PCP signaling molecules in specified groups of cells; these interventions not only perturb the polarization of the targeted cells at a subcellular level, but also perturb patterns of polarity at the multicellular level, often affecting nearby cells in characteristic ways. These kinds of experiments should, in principle, allow one to infer the architecture within and between modules, but the relationships between molecular interactions and tissue-level pattern are sufficiently complex that they defy intuitive understanding. Mathematical modeling has been an important tool to address these problems. This review explores the emergence of a local signaling hypothesis, and describes how a local intercellular signal, coupled with a directional cue, can give rise to global pattern. We will discuss the critical role mathematical modeling has played in guiding and interpreting experimental results, and speculate about future roles for mathematical modeling of PCP. Mathematical models at varying levels of abstraction have and are expected to continue contributing in distinct ways to understanding the regulation of PCP signaling. PMID:21755606

  5. Fluorescently labeled collagen binding proteins allow specific visualization of collagen in tissues and live cell culture.

    Science.gov (United States)

    Krahn, Katy Nash; Bouten, Carlijn V C; van Tuijl, Sjoerd; van Zandvoort, Marc A M J; Merkx, Maarten

    2006-03-15

    Visualization of the formation and orientation of collagen fibers in tissue engineering experiments is crucial for understanding the factors that determine the mechanical properties of tissues. In this study, collagen-specific fluorescent probes were developed using a new approach that takes advantage of the inherent specificity of collagen binding protein domains present in bacterial adhesion proteins (CNA35) and integrins (GST-alpha1I). Both collagen binding domains were obtained as fusion proteins from an Escherichia coli expression system and fluorescently labeled using either amine-reactive succinimide (CNA35) or cysteine-reactive maleimide (GST-alpha1I) dyes. Solid-phase binding assays showed that both protein-based probes are much more specific than dichlorotriazinyl aminofluorescein (DTAF), a fluorescent dye that is currently used to track collagen formation in tissue engineering experiments. The CNA35 probe showed a higher affinity for human collagen type I than did the GST-alpha1I probe (apparent K(d) values of 0.5 and 50 microM, respectively) and showed very little cross-reactivity with noncollagenous extracellular matrix proteins. The CNA35 probe was also superior to both GST-alpha1I and DTAF in visualizing the formation of collagen fibers around live human venous saphena cells. Immunohistological experiments on rat tissue showed colocalization of the CNA35 probe with collagen type I and type III antibodies. The fluorescent probes described here have important advantages over existing methods for visualization of collagen, in particular for monitoring the formation of collagen in live tissue cultures over prolonged time periods. PMID:16476406

  6. Visualization of Polarized Membrane Type 1 Matrix Metalloproteinase Activity in Live Cells by Fluorescence Resonance Energy Transfer Imaging*S⃞

    OpenAIRE

    Ouyang, Mingxing; Lu, Shaoying; Li, Xiao-Yan; Xu, Jing; Seong, Jihye; Giepmans, Ben N. G.; Shyy, John Y.-J.; Weiss, Stephen J.; Wang, Yingxiao

    2008-01-01

    Membrane type 1 matrix metalloproteinase (MT1-MMP) plays a critical role in cancer cell biology by proteolytically remodeling the extracellular matrix. Utilizing fluorescence resonance energy transfer (FRET) imaging, we have developed a novel biosensor, with its sensing element anchoring at the extracellular surface of cell membrane, to visualize MT1-MMP activity dynamically in live cells with subcellular resolution. Epidermal growth factor (EGF) induced significant FR...

  7. Scene perception and the visual control of travel direction in navigating wood ants

    OpenAIRE

    Collett, Thomas S; Lent, David D.; Graham, Paul

    2014-01-01

    This review reflects a few of Mike Land's many and varied contributions to visual science. In it, we show for wood ants, as Mike has done for a variety of animals, including readers of this piece, what can be learnt from a detailed analysis of an animal's visually guided eye, head or body movements. In the case of wood ants, close examination of their body movements, as they follow visually guided routes, is starting to reveal how they perceive and respond to their visual world and negotiate ...

  8. Comparison of digital image analysis versus visual assessment to assess survivin expression as an independent predictor of survival for patients with clear cell renal cell carcinoma✩

    OpenAIRE

    Parker, Alexander S.; Lohse, Christine M.; Leibovich, Bradley C.; Cheville, John C; Sheinin, Yuri M.; Kwon, Eugene D.

    2008-01-01

    We previously used quantitative digital image analysis to report that high immunohistochemical tumor expression levels of survivin independently predict poor outcome among patients with clear cell renal cell carcinoma. However, given the cumbersome and costly nature of digital image analysis, we evaluated simple visual assessment as an alternative to digital image analysis for assessing survivin as a predictor of clear cell renal cell carcinoma patient outcomes. We identified 310 patients tre...

  9. Fluorescent Lipids: Functional Parts of Fusogenic Liposomes and Tools for Cell Membrane Labeling and Visualization

    OpenAIRE

    Christian Kleusch; Bernd Hoffmann; Nils Hersch; Agnes Csiszár; Rudolf Merkel

    2012-01-01

    In this paper a rapid and highly efficient method for controlled incorporation of fluorescent lipids into living mammalian cells is introduced. Here, the fluorescent molecules have two consecutive functions: First, they trigger rapid membrane fusion between cellular plasma membranes and the lipid bilayers of their carrier particles, so called fusogenic liposomes, and second, after insertion into cellular membranes these molecules enable fluorescence imaging of cell membranes and membrane traf...

  10. Agency Decision-Making Control and Employment Outcomes by Vocational Rehabilitation Consumers Who Are Blind or Visually Impaired

    Science.gov (United States)

    Steinman, Bernard A.; Kwan, Ngai; Boeltzig-Brown, Heike; Haines, Kelly; Halliday, John; Foley, Susan M.

    2013-01-01

    Introduction: We hypothesized that consumers who are blind or visually impaired (that is, those who have low vision) who were served by state vocational rehabilitation agencies with decision-making control over administrative functions would experience better vocational rehabilitation outcomes than consumers served by vocational rehabilitation…

  11. Control or non-control state: that is the question! An asynchronous visual P300-based BCI approach

    Science.gov (United States)

    Pinegger, Andreas; Faller, Josef; Halder, Sebastian; Wriessnegger, Selina C.; Müller-Putz, Gernot R.

    2015-02-01

    Objective. Brain-computer interfaces (BCI) based on event-related potentials (ERP) were proven to be a reliable synchronous communication method. For everyday life situations, however, this synchronous mode is impractical because the system will deliver a selection even if the user is not paying attention to the stimulation. So far, research into attention-aware visual ERP-BCIs (i.e., asynchronous ERP-BCIs) has led to variable success. In this study, we investigate new approaches for detection of user engagement. Approach. Classifier output and frequency-domain features of electroencephalogram signals as well as the hybridization of them were used to detect the user's state. We tested their capabilities for state detection in different control scenarios on offline data from 21 healthy volunteers. Main results. The hybridization of classifier output and frequency-domain features outperformed the results of the single methods, and allowed building an asynchronous P300-based BCI with an average correct state detection accuracy of more than 95%. Significance. Our results show that all introduced approaches for state detection in an asynchronous P300-based BCI can effectively avoid involuntary selections, and that the hybrid method is the most effective approach.

  12. Retinal ganglion cell projections to the hamster suprachiasmatic nucleus, intergeniculate leaflet, and visual midbrain: bifurcation and melanopsin immunoreactivity

    Science.gov (United States)

    Morin, Lawrence P.; Blanchard, Jane H.; Provencio, Ignacio

    2003-01-01

    The circadian clock in the suprachiasmatic nucleus (SCN) receives direct retinal input via the retinohypothalamic tract (RHT), and the retinal ganglion cells contributing to this projection may be specialized with respect to direct regulation of the circadian clock. However, some ganglion cells forming the RHT bifurcate, sending axon collaterals to the intergeniculate leaflet (IGL) through which light has secondary access to the circadian clock. The present studies provide a more extensive examination of ganglion cell bifurcation and evaluate whether ganglion cells projecting to several subcortical visual nuclei contain melanopsin, a putative ganglion cell photopigment. The results showed that retinal ganglion cells projecting to the SCN send collaterals to the IGL, olivary pretectal nucleus, and superior colliculus, among other places. Melanopsin-immunoreactive (IR) ganglion cells are present in the hamster retina, and some of these cells project to the SCN, IGL, olivary pretectal nucleus, or superior colliculus. Triple-label analysis showed that melanopsin-IR cells bifurcate and project bilaterally to each SCN, but not to the other visual nuclei evaluated. The melanopsin-IR cells have photoreceptive characteristics optimal for circadian rhythm regulation. However, the presence of moderately widespread bifurcation among ganglion cells projecting to the SCN, and projection by melanopsin-IR cells to locations distinct from the SCN and without known rhythm function, suggest that this ganglion cell type is generalized, rather than specialized, with respect to the conveyance of photic information to the brain. Copyright 2003 Wiley-Liss, Inc.

  13. Quantitative operando visualization of the energy band depth profile in solar cells.

    Science.gov (United States)

    Chen, Qi; Mao, Lin; Li, Yaowen; Kong, Tao; Wu, Na; Ma, Changqi; Bai, Sai; Jin, Yizheng; Wu, Dan; Lu, Wei; Wang, Bing; Chen, Liwei

    2015-01-01

    The energy band alignment in solar cell devices is critically important because it largely governs elementary photovoltaic processes, such as the generation, separation, transport, recombination and collection of charge carriers. Despite the expenditure of considerable effort, the measurement of energy band depth profiles across multiple layers has been extremely challenging, especially for operando devices. Here we present direct visualization of the surface potential depth profile over the cross-sections of operando organic photovoltaic devices using scanning Kelvin probe microscopy. The convolution effect due to finite tip size and cantilever beam crosstalk has previously prohibited quantitative interpretation of scanning Kelvin probe microscopy-measured surface potential depth profiles. We develop a bias voltage-compensation method to address this critical problem and obtain quantitatively accurate measurements of the open-circuit voltage, built-in potential and electrode potential difference. PMID:26166580

  14. Quantitative operando visualization of the energy band depth profile in solar cells

    Science.gov (United States)

    Chen, Qi; Mao, Lin; Li, Yaowen; Kong, Tao; Wu, Na; Ma, Changqi; Bai, Sai; Jin, Yizheng; Wu, Dan; Lu, Wei; Wang, Bing; Chen, Liwei

    2015-07-01

    The energy band alignment in solar cell devices is critically important because it largely governs elementary photovoltaic processes, such as the generation, separation, transport, recombination and collection of charge carriers. Despite the expenditure of considerable effort, the measurement of energy band depth profiles across multiple layers has been extremely challenging, especially for operando devices. Here we present direct visualization of the surface potential depth profile over the cross-sections of operando organic photovoltaic devices using scanning Kelvin probe microscopy. The convolution effect due to finite tip size and cantilever beam crosstalk has previously prohibited quantitative interpretation of scanning Kelvin probe microscopy-measured surface potential depth profiles. We develop a bias voltage-compensation method to address this critical problem and obtain quantitatively accurate measurements of the open-circuit voltage, built-in potential and electrode potential difference.

  15. Visualization of the Activity of Rac1 Small GTPase in a Cell

    International Nuclear Information System (INIS)

    Rho family G proteins including Rac regulate a variety of cellular functions, such as morphology, motility, and gene expression. Here we developed a fluorescence resonance energy transfer-based analysis in which we could monitor the activity of Rac1. To detect fluorescence resonance energy transfer, yellow fluorescent protein fused Rac1 and cyan fluorescent protein fused Cdc42-Rac1-interaction-binding domain of Pak1 protein were used as intermolecular probes of FRET. The fluorophores were separated with linear unmixing method. The fluorescence resonance energy transfer efficiency was measured by acceptor photobleaching assisted assay. With these methods, the Rac1 activity was visualized in a cell. The present findings indicate that this approach is sensitive enough to achieve results similar to those from ratiometric fluorescence resonance energy transfer analysis

  16. Photoinduced Charge Transport in a BHJ Solar Cell Controlled by an External Electric Field

    OpenAIRE

    Yongqing Li; Yanting Feng; Mengtao Sun

    2015-01-01

    This study investigated theoretical photoinduced charge transport in a bulk heterojunction (BHJ) solar cell controlled by an external electric field. Our method for visualizing charge difference density identified the excited state properties of photoinduced charge transfer, and the charge transfer excited states were distinguished from local excited states during electronic transitions. Furthermore, the calculated rates for the charge transfer revealed that the charge transfer was strongly i...

  17. Toward a visual cognitive system using active top-down saccadic control

    NARCIS (Netherlands)

    J. LaCroix; E. Postma; J. van den Herik; J. Murre

    2008-01-01

    The saccadic selection of relevant visual input for preferential processing allows the efficient use of computational resources. Based on saccadic active human vision, we aim to develop a plausible saccade-based visual cognitive system for a humanoid robot. This paper presents two initial steps towa

  18. Visualization of Assembly Intermediates and Budding Vacuoles of Singapore Grouper Iridovirus in Grouper Embryonic Cells

    Science.gov (United States)

    Liu, Yang; Tran, Bich Ngoc; Wang, Fan; Ounjai, Puey; Wu, Jinlu; Hew, Choy L.

    2016-01-01

    Iridovirid infection is associated with the catastrophic loss in aquaculture industry and the population decline of wild amphibians and reptiles, but none of the iridovirid life cycles have been well explored. Here, we report the detailed visualization of the life cycle of Singapore grouper iridovirus (SGIV) in grouper cells by cryo-electron microscopy (cryoEM) and tomography (ET). EM imaging revealed that SGIV viral particles have an outer capsid layer, and the interaction of this layer with cellular plasma membrane initiates viral entry. Subsequent viral replication leads to formation of a viral assembly site (VAS), where membranous structures emerge as precursors to recruit capsid proteins to form an intermediate, double-shell, crescent-shaped structure, which curves to form icosahedral capsids. Knockdown of the major capsid protein eliminates the formation of viral capsids. As capsid formation progresses, electron-dense materials known to be involved in DNA encapsidation accumulate within the capsid until it is fully occupied. Besides the well-known budding mechanism through the cell periphery, we demonstrate a novel budding process in which viral particles bud into a tubular-like structure within vacuoles. This budding process may denote a new strategy used by SGIV to disseminate viral particles into neighbor cells while evading host immune response. PMID:26727547

  19. Hierarchical structural control of visual properties in self-assembled photonic-plasmonic pigments.

    Science.gov (United States)

    Koay, Natalie; Burgess, Ian B; Kay, Theresa M; Nerger, Bryan A; Miles-Rossouw, Malaika; Shirman, Tanya; Vu, Thy L; England, Grant; Phillips, Katherine R; Utech, Stefanie; Vogel, Nicolas; Kolle, Mathias; Aizenberg, Joanna

    2014-11-17

    We present a simple one-pot co-assembly method for the synthesis of hierarchically structured pigment particles consisting of silica inverse-opal bricks that are doped with plasmonic absorbers. We study the interplay between the plasmonic and photonic resonances and their effect on the visual appearance of macroscopic collections of photonic bricks that are distributed in randomized orientations. Manipulating the pore geometry tunes the wavelength- and angle-dependence of the scattering profile, which can be engineered to produce angle-dependent Bragg resonances that can either enhance or contrast with the color produced by the plasmonic absorber. By controlling the overall dimensions of the photonic bricks and their aspect ratios, their preferential alignment can either be encouraged or suppressed. This causes the Bragg resonance to appear either as uniform color travel in the former case or as sparse iridescent sparkle in the latter case. By manipulating the surface chemistry of these photonic bricks, which introduces a fourth length-scale (molecular) of independent tuning into our design, we can further engineer interactions between liquids and the pores. This allows the structural color to be maintained in oil-based formulations, and enables the creation of dynamic liquid-responsive images from the pigment. PMID:25402020

  20. A testbed for visual based navigation and control during space rendezvous operations

    Science.gov (United States)

    Sabatini, Marco; Palmerini, Giovanni B.; Gasbarri, Paolo

    2015-12-01

    Visual based navigation systems are considered essential tools in the framework of close proximity space operations, such as rendezvous and docking, both in the role of primary devices and in the role of back-up systems. Autonomy in such operations is a requirement that has been increasingly underlined, especially in the case of non-cooperative tumbling targets, as for example in the active debris removal concepts. In such a case the time delays and the partial communication coverage make the human intervention unsuitable. On the other hand, robustness of the guidance and control system is certainly an issue for autonomous docking missions. In this paper, algorithms for autonomous relative navigation by means of a single camera are detailed, and tested both numerically and experimentally. At the same time a guidance strategy has been defined in order to increase the system robustness. In order to prove the soundness of the proposed navigation and guidance approach a docking mission has been successfully performed by means of two free floating platforms - a chaser and a target - on an air-bearing table, both in a nominal and in a non-nominal (i.e. with a tumbling target) scenarios.

  1. Extended temporal integration in rapid serial visual presentation: Attentional control at Lag 1 and beyond.

    Science.gov (United States)

    Akyürek, Elkan G; Wolff, Michael J

    2016-07-01

    In the perception of target stimuli in rapid serial visual presentations, the process of temporal integration plays an important role when two targets are presented in direct succession (at Lag 1), causing them to be perceived as a singular episodic event. This has been associated with increased reversals of target order report and elevated task performance in classic paradigms. Yet, most current models of temporal attention do not incorporate a mechanism of temporal integration and it is currently an open question whether temporal integration is a factor in attentional processing: It might be an independent process, perhaps little more than a sensory sampling rate parameter, isolated to Lag 1, where it leaves the attentional dynamics otherwise unaffected. In the present study, these boundary conditions were tested. Temporal target integration was observed across sequences of three targets spanning an interval of 240ms. Integration rates furthermore depended strongly on bottom-up attentional filtering, and to a lesser degree on top-down control. The results support the idea that temporal integration is an adaptive process that is part of, or at least interacts with, the attentional system. Implications for current models of temporal attention are discussed. PMID:27155801

  2. Sistema de servocontrol visual empleando redes neuronales y filtros en el dominio de CIELAB//Visual servo-control system using neural networks and filters based on CIELAB

    Directory of Open Access Journals (Sweden)

    Germán Buitrago Salazar

    2015-05-01

    Full Text Available En este trabajo se presentan los resultados de un sistema servocontrol visual de un brazo robótico de seis grados de libertad. Para esto, se utiliza una red neuronal de tipo feed forward, entrenada por back propagation, para determinar la distancia entre el brazo robótico y un objeto de referencia, que permite ubicarlo en un espacio de trabajo. Las entradas de la red corresponden a la información obtenida de las imágenes capturadas por el Kinect, utilizando un filtro que discrimina la posición de los elementos, en el espacio de color CIELAB (Commission Internationale de l'Eclairage L*a*b components. El resultado de esta investigación demostró que la distancia estimada por la red tiene un margen de error menor, que el algoritmo propuesto en otros trabajos. Igualmente, se probó que el sistema de procesamiento de imágenes es más robusto a ruidos digitales, en comparación con los sistemas que utilizan filtros en el dominio RGB (Red-Green-Blue.Palabras claves: sistema de servocontrol visual, CIELAB, redes neuronales, filtrado de imágenes.______________________________________________________________________________AbstractIn this paper the results of visual servo-control system for a robotic arm with six degrees of freedom are presented. For this purpose, a feed fordward neural network, which was trained by back propagation, is used to determine the distance between the robot arm and a reference object and sitting the robot in the workspace. The inputs of neural network correspond to the information obtained from the images captured by the Kinect, using a filter that discriminates the position of the elements in the CIELAB (Commission Internationale de l'Eclairage L*a*bcomponents color space. The result of this research showed that the estimated distance with the network has an errorless than the algorithm proposed in other works. Similarly, it was proved that the image processing system is more robust to digital noise, compared to

  3. Visualizing Stable Features in Live Cell Nucleus for Evaluation of the Cell Global Motion Compensation

    Czech Academy of Sciences Publication Activity Database

    Sorokin, D.V.; Suchánková, Jana; Bártová, Eva; Matula, P.

    2014-01-01

    Roč. 60, č. 1 (2014), s. 45-49. ISSN 0015-5500 R&D Projects: GA ČR GBP302/12/G157; GA MŠk(CZ) EE2.3.30.0030 Institutional support: RVO:68081707 Keywords : cell global motion compensation * UV laser bleaching * image registration Subject RIV: BO - Biophysics Impact factor: 1.000, year: 2014

  4. The Microsoft Visual Studio Software Development For 5 DOF Nuclear Malaysia Robot Arm V2 Control System

    International Nuclear Information System (INIS)

    This paper presents the Microsoft visual studio development for 5DOF Nuclear Malaysia Robot Arm V2 control system. The kinematics analysis is the study of the relationship between the individual joints of robot manipulator, the position and orientation of the end-effector. The Denavit-Hartenberg (DH) model is used to model the robot links and joints. Both forward and inverse kinematic are presented. The simulation software has been developed by using Microsoft visual studio to solve the robot arms kinematic behavior. (author)

  5. Acute and Chronic Effect of Acoustic and Visual Cues on Gait Training in Parkinson's Disease: A Randomized, Controlled Study

    OpenAIRE

    Roberto De Icco; Cristina Tassorelli; Eliana Berra; Monica Bolla; Claudio Pacchetti; Giorgio Sandrini

    2015-01-01

    In this randomized controlled study we analyse and compare the acute and chronic effects of visual and acoustic cues on gait performance in Parkinson’s Disease (PD). We enrolled 46 patients with idiopathic PD who were assigned to 3 different modalities of gait training: (1) use of acoustic cues, (2) use of visual cues, or (3) overground training without cues. All patients were tested with kinematic analysis of gait at baseline (T0), at the end of the 4-week rehabilitation programme (T1), and ...

  6. Restoration of visual function by expression of a light-gated mammalian ion channel in retinal ganglion cells or ON-bipolar cells

    OpenAIRE

    Gaub, Benjamin M.; Berry, Michael H.; Holt, Amy E.; Reiner, Andreas; Kienzler, Michael A; Dolgova, Natalia; Nikonov, Sergei; Aguirre, Gustavo D.; Beltran, William A.; Flannery, John G.; Isacoff, Ehud Y.

    2014-01-01

    We restored visual function to animal models of human blindness using a chemical compound that photosensitizes a mammalian ion channel. Virus-mediated expression of this light sensor in surviving retinal cells of blind mice restored light responses in vitro, reanimated innate light avoidance, and enabled learned visually guided behavior. The treatment also restored light responses to the retina of blind dogs. Patients that might benefit from this treatment would need to have intact ganglion c...

  7. Epigenetic control of cell identity and plasticity

    KAUST Repository

    Orlando, Valerio

    2014-04-02

    The DNA centered dogma for genetic information and cell identity is now evolving into a much more complex and flexible dimension provided by the discovery of the Epigenome. This comprises those chromosome structural and topological components that complement DNA information and contribute to genome functional organization. Current concept is that the Epigenome constitutes the dynamic molecular interface allowing the Genome to interact with the Environment. Exploring how the genome interacts with the environment is a key to fully understand cellular and complex organism mechanisms of adaptation and plasticity. Our work focuses on the role of an essential, specialized group or chromatin associated proteins named Polycomb (PcG) that control maintenance of transcription programs during development and in adult life. In particular PcG proteins exert epigenetic “memory” function by modifying chromosome structures at various levels to maintain gene silencing in particular through cell division. While in the past decade substantial progress was made in understanding PcG mechanisms acting in development and partially during cell cycle, very little is known about their role in adult post-mitotic tissues and more in general the role of the epigenome in adaptation. To this, we studied the role of PcG in the context of mammalian skeletal muscle cell differentiation. We previously reported specific dynamics of PRC2 proteins in myoblasts and myotubes, in particular the dynamics of PcG Histone H3 K27 Methyl Transferases (HMT), EZH2 and EZH1, the latter apparently replacing for EZH2 in differentiated myotubes. Ezh1 protein, although almost identical to Ezh2, shows a weak H3K27 HMT activity and its primary function remains elusive. Recent ChIPseq studies performed in differentiating muscle cells revealed that Ezh1 associates with active and not repressed regulatory regions to control RNA pol II elongation. Since H3K27 tri-methylation levels are virtually steady in non

  8. Visualizing early splenic memory CD8+ T cells reactivation against intracellular bacteria in the mouse.

    Directory of Open Access Journals (Sweden)

    Marc Bajénoff

    Full Text Available Memory CD8(+ T cells represent an important effector arm of the immune response in maintaining long-lived protective immunity against viruses and some intracellular bacteria such as Listeria monocytogenes (L.m. Memory CD8(+ T cells are endowed with enhanced antimicrobial effector functions that perfectly tail them to rapidly eradicate invading pathogens. It is largely accepted that these functions are sufficient to explain how memory CD8(+ T cells can mediate rapid protection. However, it is important to point out that such improved functional features would be useless if memory cells were unable to rapidly find the pathogen loaded/infected cells within the infected organ. Growing evidences suggest that the anatomy of secondary lymphoid organs (SLOs fosters the cellular interactions required to initiate naive adaptive immune responses. However, very little is known on how the SLOs structures regulate memory immune responses. Using Listeria monocytogenes (L.m as a murine infection model and imaging techniques, we have investigated if and how the architecture of the spleen plays a role in the reactivation of memory CD8(+ T cells and the subsequent control of L.m growth. We observed that in the mouse, memory CD8(+ T cells start to control L.m burden 6 hours after the challenge infection. At this very early time point, L.m-specific and non-specific memory CD8(+ T cells localize in the splenic red pulp and form clusters around L.m infected cells while naïve CD8(+ T cells remain in the white pulp. Within these clusters that only last few hours, memory CD8(+ T produce inflammatory cytokines such as IFN-gamma and CCL3 nearby infected myeloid cells known to be crucial for L.m killing. Altogether, we describe how memory CD8(+ T cells trafficking properties and the splenic micro-anatomy conjugate to create a spatio-temporal window during which memory CD8(+ T cells provide a local response by secreting effector molecules around infected cells.

  9. Uveal Melanoma Treated With Iodine-125 Episcleral Plaque: An Analysis of Dose on Disease Control and Visual Outcomes

    International Nuclear Information System (INIS)

    Purpose: To investigate, in the treatment of uveal melanomas, how tumor control, radiation toxicity, and visual outcomes are affected by the radiation dose at the tumor apex. Methods and Materials: A retrospective review was performed to evaluate patients treated for uveal melanoma with 125I plaques between 1988 and 2010. Radiation dose is reported as dose to tumor apex and dose to 5 mm. Primary endpoints included time to local failure, distant failure, and death. Secondary endpoints included eye preservation, visual acuity, and radiation-related complications. Univariate and multivariate analyses were performed to determine associations between radiation dose and the endpoint variables. Results: One hundred ninety patients with sufficient data to evaluate the endpoints were included. The 5-year local control rate was 91%. The 5-year distant metastases rate was 10%. The 5-year overall survival rate was 84%. There were no differences in outcome (local control, distant metastases, overall survival) when dose was stratified by apex dose quartile (<69 Gy, 69-81 Gy, 81-89 Gy, >89 Gy). However, increasing apex dose and dose to 5-mm depth were correlated with greater visual acuity loss (P=.02, P=.0006), worse final visual acuity (P=.02, P<.0001), and radiation complications (P<.0001, P=.0009). In addition, enucleation rates were worse with increasing quartiles of dose to 5 mm (P=.0001). Conclusions: Doses at least as low as 69 Gy prescribed to the tumor apex achieve rates of local control, distant metastasis–free survival, and overall survival that are similar to radiation doses of 85 Gy to the tumor apex, but with improved visual outcomes

  10. Uveal Melanoma Treated With Iodine-125 Episcleral Plaque: An Analysis of Dose on Disease Control and Visual Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Bradford A. [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Mettu, Pradeep; Vajzovic, Lejla [Department of Ophthalmology, Duke University, Durham, North Carolina (United States); Rivera, Douglas [Austin Cancer Centers, Austin, Texas (United States); Alkaissi, Ali; Steffey, Beverly A.; Cai, Jing [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Stinnett, Sandra [Department of Biostatistics and Informatics, Duke University, Durham, North Carolina (United States); Dutton, Jonathan J. [Department of Ophthalmology, University of North Carolina, Chapel Hill, North Carolina (United States); Buckley, Edward G. [Department of Ophthalmology, Duke University, Durham, North Carolina (United States); Halperin, Edward [Department of Radiation Oncology, New York Medical College, Valhalla, New York (United States); Marks, Lawrence B. [Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina (United States); Mruthyunjaya, Prithvi [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Department of Ophthalmology, Duke University, Durham, North Carolina (United States); Kirsch, David G., E-mail: david.kirsch@duke.edu [Department of Radiation Oncology, Duke University, Durham, North Carolina (United States); Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina (United States)

    2014-05-01

    Purpose: To investigate, in the treatment of uveal melanomas, how tumor control, radiation toxicity, and visual outcomes are affected by the radiation dose at the tumor apex. Methods and Materials: A retrospective review was performed to evaluate patients treated for uveal melanoma with {sup 125}I plaques between 1988 and 2010. Radiation dose is reported as dose to tumor apex and dose to 5 mm. Primary endpoints included time to local failure, distant failure, and death. Secondary endpoints included eye preservation, visual acuity, and radiation-related complications. Univariate and multivariate analyses were performed to determine associations between radiation dose and the endpoint variables. Results: One hundred ninety patients with sufficient data to evaluate the endpoints were included. The 5-year local control rate was 91%. The 5-year distant metastases rate was 10%. The 5-year overall survival rate was 84%. There were no differences in outcome (local control, distant metastases, overall survival) when dose was stratified by apex dose quartile (<69 Gy, 69-81 Gy, 81-89 Gy, >89 Gy). However, increasing apex dose and dose to 5-mm depth were correlated with greater visual acuity loss (P=.02, P=.0006), worse final visual acuity (P=.02, P<.0001), and radiation complications (P<.0001, P=.0009). In addition, enucleation rates were worse with increasing quartiles of dose to 5 mm (P=.0001). Conclusions: Doses at least as low as 69 Gy prescribed to the tumor apex achieve rates of local control, distant metastasis–free survival, and overall survival that are similar to radiation doses of 85 Gy to the tumor apex, but with improved visual outcomes.

  11. Effectiveness of the addition of citicoline to patching in the treatment of amblyopia around visual maturity: A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Prachee Vasant Pawar

    2014-01-01

    Full Text Available Aim: To study the effectiveness of the addition of citicoline to patching in the treatment of amblyopia in the age group of 4-13 years. Materials and Methods: A randomized controlled trial, which included patients who were randomly divided into two groups. Both the groups received patching therapy till plateau was achieved in phase 1 of the study. Then in phase 2, group I received citicoline plus patching and group II continued to receive only patching. Outcome Measures: Outcome was measured by the visual acuity in logMAR every month in phase 1 till plateau was achieved and then for 12 months in phase 2. Results: No significant difference was found in the mean visual acuities in these two groups in phase 1 till plateau was reached. In phase 2, for the initial four months, there was no significant difference in the visual acuities in these two groups, at the respective intervals. However, five months onward, up to 12 months, there was a significant difference in the visual acuities in these groups.The result was the same in younger patients ( seven years of age. In phase 2, the mean proportional improvement in group I was significantly more than that in group II, at two months and onward, at the respective intervals. Conclusion: The improvement in visual acuity with citicoline plus patching was significantly more than that with patching alone, in one year of treatment.

  12. Control of the visual and tactile aspects of poultry food according to the poultry food behavior by image analysis

    Science.gov (United States)

    Hachemi, R.; Vincent, N.; Lomenie, N.

    2007-01-01

    This study tries to connect the poultry food behavior to the visual and tactile characteristics of the food. The aim of the work is to make it possible to control the visual and tactile aspects of food (food pellets), by means of image analysis. These aspects are often suspected to explain the undesirable behavior of the poultries, which can reject a food, showing however optimal nutritional characteristics. These incidents involve important negative consequences as well for the animal as for the poultry breeder, with a major degradation of the technical and economic performances. Many zootechnical studies and observations in breeding testify to the sensitivity of the poultries to the visual and tactile aspects of food, but measurements classically used to characterize them do not allow explaining this phenomenon. Color, texture and shape features extracted from images of pellets will constitute effective and practical measures to describe their visual and tactile aspects. We show that a pellets classification based on visual features and supervised by a set of poultry food behavior labels allows to select a set of discriminating features.

  13. Three counting methods agree on cell and neuron number in chimpanzee primary visual cortex

    Directory of Open Access Journals (Sweden)

    Daniel James Miller

    2014-05-01

    Full Text Available Determining the cellular composition of specific brain regions is crucial to our understanding of the function of neurobiological systems. It is therefore useful to identify the extent to which different methods agree when estimating the same properties of brain circuitry. In this study, we estimated the number of neuronal and non-neuronal cells in the primary visual cortex (area 17 or V1 of both hemispheres from a single chimpanzee. Specifically, we processed samples distributed across V1 of the right hemisphere after cortex was flattened into a sheet using two variations of the isotropic fractionator cell and neuron counting method. We processed the left hemisphere as serial brain slices for stereological investigation. The goal of this study was to evaluate the agreement between these methods in the most direct manner possible by comparing estimates of cell density across one brain region of interest in a single individual. In our hands, these methods produced similar estimates of the total cellular population (approximately 1 billion as well as the number of neurons (approximately 675 million in chimpanzee V1, providing evidence that both techniques estimate the same parameters of interest. In addition, our results indicate the strengths of each distinct tissue preparation procedure, highlighting the importance of attention to anatomical detail. In summary, we found that the isotropic fractionator and the stereological optical fractionator produced concordant estimates of the cellular composition of V1, and that this result supports the conclusion that chimpanzees conform to the primate pattern of exceptionally high packing density in V1. Ultimately, our data suggest that investigators can optimize their experimental approach by using any of these counting methods to obtain reliable cell and neuron counts.

  14. Visualizing Nanoscale Distribution of Corrosion Cells by Open-Loop Electric Potential Microscopy.

    Science.gov (United States)

    Honbo, Kyoko; Ogata, Shoichiro; Kitagawa, Takuya; Okamoto, Takahiro; Kobayashi, Naritaka; Sugimoto, Itto; Shima, Shohei; Fukunaga, Akira; Takatoh, Chikako; Fukuma, Takeshi

    2016-02-23

    Corrosion is a traditional problem but still one of the most serious problems in industry. To reduce the huge economic loss caused by corrosion, tremendous effort has been made to understand, predict and prevent it. Corrosion phenomena are generally explained by the formation of corrosion cells at a metal-electrolyte interface. However, experimental verification of their nanoscale distribution has been a major challenge owing to the lack of a method able to visualize the local potential distribution in an electrolytic solution. In this study, we have investigated the nanoscale corrosion behavior of Cu fine wires and a duplex stainless steel by in situ imaging of local corrosion cells by open-loop electric potential microscopy (OL-EPM). For both materials, potential images obtained by OL-EPM show nanoscale contrasts, where areas of higher and lower potential correspond to anodic areas (i.e., corrosion sites) and cathodic areas, respectively. This imaging capability allows us to investigate the real-time transition of local corrosion sites even when surface structures show little change. This is particularly useful for investigating reactions under surface oxide layers or highly corrosion-resistant materials as demonstrated here. The proposed technique should be applicable to the study of other redox reactions on a battery electrode or a catalytic material. The results presented here open up such future applications of OL-EPM in nanoscale electrochemistry. PMID:26811989

  15. Visualization of NRAS RNA G-Quadruplex Structures in Cells with an Engineered Fluorogenic Hybridization Probe.

    Science.gov (United States)

    Chen, Shuo-Bin; Hu, Ming-Hao; Liu, Guo-Cai; Wang, Jin; Ou, Tian-Miao; Gu, Lian-Quan; Huang, Zhi-Shu; Tan, Jia-Heng

    2016-08-24

    The RNA G-quadruplex is an important secondary structure formed by guanine-rich RNA sequences. However, its folding studies have mainly been studied in vitro. Accurate identification of RNA G-quadruplex formation within a sequence of interest remains difficult in cells. Herein, and based on the guanine-rich sequence in the 5'-UTR of NRAS mRNA, we designed and synthesized the first G-quadruplex-triggered fluorogenic hybridization (GTFH) probe, ISCH-nras1, for the unique visualization of the G-quadruplexes that form in this region. ISCH-nras1 is made up of two parts: The first is a fluorescent light-up moiety specific to G-quadruplex structures, and the second is a DNA molecule that can hybridize with a sequence that is adjacent to the guanine-rich sequence in the NRAS mRNA 5'-UTR. Further evaluation studies indicated that ISCH-nras1 could directly and precisely detect the targeted NRAS RNA G-quadruplex structures, both in vitro and in cells. Thus, this GTFH probe was a useful tool for directly investigating the folding of G-quadruplex structures within an RNA of interest and represents a new direction for the design of smart RNA G-quadruplex probes. PMID:27508892

  16. A "turn-on" silver nanocluster based fluorescent sensor for folate receptor detection and cancer cell imaging under visual analysis.

    Science.gov (United States)

    Jiang, Hong; Xu, Gang; Sun, Yimin; Zheng, Weiwei; Zhu, Xiangxiang; Wang, Baojuan; Zhang, Xiaojun; Wang, Guangfeng

    2015-07-28

    A novel terminal protection based label-free and "turn-on" fluorescent sensor for detection of folate receptors (FRs) and HeLa cells is developed by fluorescence resonance energy transfer (FRET) between single-walled carbon nanotubes (SWCNTs) and silver nanoclusters (AgNCs). Multilevel visual analysis (m(2)VA) was firstly proposed and applied in optimizing the experimental parameters. PMID:26108636

  17. The effects of pattern shape, subliminal stimulation, and voluntary control on multistable visual perception

    Czech Academy of Sciences Publication Activity Database

    Taddei-Ferretti, C.; Radilová, Jiřina; Musio, C.; Santillo, S.; Cibelli, E.; Cotugno, A.; Radil, Tomáš

    2008-01-01

    Roč. 1225, - (2008), s. 163-170. ISSN 0006-8993 Institutional research plan: CEZ:AV0Z50110509 Keywords : visual perception * figure reversal Subject RIV: FH - Neurology Impact factor: 2.494, year: 2008

  18. An interactive graphical system of XBT data quality control and visualization

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Ghosh, A.K.; Sarupria, J.S.; Gopalakrishna, V.V.

    better visual effect. Though the system is basically designed for Indian Oceandataarchive,itcanbeusedgloballyexceptforthe inversionfilterexistingintheQCmodule. In all stages of the quality checks, the general philosophy adopted is that the data value...

  19. Visualizing viral protein structures in cells using genetic probes for correlated light and electron microscopy.

    Science.gov (United States)

    Ou, Horng D; Deerinck, Thomas J; Bushong, Eric; Ellisman, Mark H; O'Shea, Clodagh C

    2015-11-15

    Structural studies of viral proteins most often use high-resolution techniques such as X-ray crystallography, nuclear magnetic resonance, single particle negative stain, or cryo-electron microscopy (EM) to reveal atomic interactions of soluble, homogeneous viral proteins or viral protein complexes. Once viral proteins or complexes are separated from their host's cellular environment, their natural in situ structure and details of how they interact with other cellular components may be lost. EM has been an invaluable tool in virology since its introduction in the late 1940's and subsequent application to cells in the 1950's. EM studies have expanded our knowledge of viral entry, viral replication, alteration of cellular components, and viral lysis. Most of these early studies were focused on conspicuous morphological cellular changes, because classic EM metal stains were designed to highlight classes of cellular structures rather than specific molecular structures. Much later, to identify viral proteins inducing specific structural configurations at the cellular level, immunostaining with a primary antibody followed by colloidal gold secondary antibody was employed to mark the location of specific viral proteins. This technique can suffer from artifacts in cellular ultrastructure due to compromises required to provide access to the immuno-reagents. Immunolocalization methods also require the generation of highly specific antibodies, which may not be available for every viral protein. Here we discuss new methods to visualize viral proteins and structures at high resolutions in situ using correlated light and electron microscopy (CLEM). We discuss the use of genetically encoded protein fusions that oxidize diaminobenzidine (DAB) into an osmiophilic polymer that can be visualized by EM. Detailed protocols for applying the genetically encoded photo-oxidizing protein MiniSOG to a viral protein, photo-oxidation of the fusion protein to yield DAB polymer staining, and

  20. When is visual information used to control locomotion when descending a kerb?

    Directory of Open Access Journals (Sweden)

    John G Buckley

    Full Text Available BACKGROUND: Descending kerbs during locomotion involves the regulation of appropriate foot placement before the kerb-edge and foot clearance over it. It also involves the modulation of gait output to ensure the body-mass is safely and smoothly lowered to the new level. Previous research has shown that vision is used in such adaptive gait tasks for feedforward planning, with vision from the lower visual field (lvf used for online updating. The present study determined when lvf information is used to control/update locomotion when stepping from a kerb. METHODOLOGY/PRINCIPAL FINDINGS: 12 young adults stepped down a kerb during ongoing gait. Force sensitive resistors (attached to participants' feet interfaced with an high-speed PDLC 'smart glass' sheet, allowed the lvf to be unpredictably occluded at either heel-contact of the penultimate or final step before the kerb-edge up to contact with the lower level. Analysis focussed on determining changes in foot placement distance before the kerb-edge, clearance over it, and in kinematic measures of the step down. Lvf occlusion from the instant of final step contact had no significant effect on any dependant variable (p>0.09. Occlusion of the lvf from the instant of penultimate step contact had a significant effect on foot clearance and on several kinematic measures, with findings consistent with participants becoming uncertain regarding relative horizontal location of the kerb-edge. CONCLUSION/SIGNIFICANCE: These findings suggest concurrent feedback of the lower limb, kerb-edge, and/or floor area immediately in front/below the kerb is not used when stepping from a kerb during ongoing gait. Instead heel-clearance and pre-landing-kinematic parameters are determined/planned using lvf information acquired in the penultimate step during the approach to the kerb-edge, with information related to foot placement before the kerb-edge being the most salient.

  1. Selective optical control of synaptic transmission in the subcortical visual pathway by activation of viral vector-expressed halorhodopsin.

    Directory of Open Access Journals (Sweden)

    Katsuyuki Kaneda

    Full Text Available The superficial layer of the superior colliculus (sSC receives visual inputs via two different pathways: from the retina and the primary visual cortex. However, the functional significance of each input for the operation of the sSC circuit remains to be identified. As a first step toward understanding the functional role of each of these inputs, we developed an optogenetic method to specifically suppress the synaptic transmission in the retino-tectal pathway. We introduced enhanced halorhodopsin (eNpHR, a yellow light-sensitive, membrane-targeting chloride pump, into mouse retinal ganglion cells (RGCs by intravitreously injecting an adeno-associated virus serotype-2 vector carrying the CMV-eNpHR-EYFP construct. Several weeks after the injection, whole-cell recordings made from sSC neurons in slice preparations revealed that yellow laser illumination of the eNpHR-expressing retino-tectal axons, putatively synapsing onto the recorded cells, effectively inhibited EPSCs evoked by electrical stimulation of the optic nerve layer. We also showed that sSC spike activities elicited by visual stimulation were significantly reduced by laser illumination of the sSC in anesthetized mice. These results indicate that photo-activation of eNpHR expressed in RGC axons enables selective blockade of retino-tectal synaptic transmission. The method established here can most likely be applied to a variety of brain regions for studying the function of individual inputs to these regions.

  2. Engineering models and methods for industrial cell control

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1997-01-01

    This paper is concerned with the engineering, i.e. the designing and making, of industrial cell control systems. The focus is on automated robot welding cells in the shipbuilding industry. The industrial research project defines models and methods for design and implemen-tation of computer based....... Further, an engineering methodology is defined. The three elements enablers, architecture and methodology constitutes the Cell Control Engineering concept which has been defined and evaluated through the implementation of two cell control systems for robot welding cells in production at ODENSE STEEL...... SHIPYARD.It is concluded that cell control technology provides for increased performance in production systems, and that the Cell Control Engineering concept reduces the effort for providing and operating high quality and high functionality cell control solutions for the industry....

  3. Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

    Science.gov (United States)

    Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

    1997-01-01

    Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

  4. Structure and Control Strategies of Fuel Cell Vehicle

    Institute of Scientific and Technical Information of China (English)

    宋建国; 张承宁; 孙逢春; 钟秋海

    2004-01-01

    The structure and kinds of the fuel cell vehicle (FCV) and the mathematical model of the fuel cell processor are discussed in detail. FCV includes many parts: the fuel cell thermal and water management, fuel supply, air supply and distribution, AC motor drive, main and auxiliary power management, and overall vehicle control system. So it requires different kinds of control strategies, such as the PID method, zero-pole method, optimal control method, fuzzy control and neural network control. Along with the progress of control method, the fuel cell vehicle's stability and reliability is up-and-up. Experiment results show FCV has high energy efficiency.

  5. A piloted simulator investigation of side-stick controller/stability and control augmentation system requirements for helicopter visual flight tasks

    Science.gov (United States)

    Landis, K. H.; Dunford, P. J.; Aiken, E. W.; Hilbert, K. B.

    1984-01-01

    A piloted simulator experiment was conducted to assess the effects of side-stick controller characteristics and level of stability and control augmentation on handling qualities for several low-altitude control tasks. Visual flight tasks were simulated using four-window computer-generated imagery depicting either a nap-of-the-earth course or a runway with obstacles positioned to provide a slalom course. Both low speed and forward flight control laws were implemented, and a method for automatically switching control modes was developed. Variations in force-deflection characteristics and the number of axes controlled through an integrated side-stick were investigated. With high levels of stability and control augmentation, a four-axis controller with small-deflection in all four axes achieved satisfactory handling qualities for low-speed tasks.

  6. Assessing the role of cell-surface molecules in central synaptogenesis in the Drosophila visual system.

    Directory of Open Access Journals (Sweden)

    Sandra Berger-Müller

    Full Text Available A hallmark of the central nervous system is its spatial and functional organization in synaptic layers. During neuronal development, axons form transient contacts with potential post-synaptic elements and establish synapses with appropriate partners at specific layers. These processes are regulated by synaptic cell-adhesion molecules. In the Drosophila visual system, R7 and R8 photoreceptor subtypes target distinct layers and form en passant pre-synaptic terminals at stereotypic loci of the axonal shaft. A leucine-rich repeat transmembrane protein, Capricious (Caps, is known to be selectively expressed in R8 axons and their recipient layer, which led to the attractive hypothesis that Caps mediates R8 synaptic specificity by homophilic adhesion. Contradicting this assumption, our results indicate that Caps does not have a prominent role in synaptic-layer targeting and synapse formation in Drosophila photoreceptors, and that the specific recognition of the R8 target layer does not involve Caps homophilic axon-target interactions. We generated flies that express a tagged synaptic marker to evaluate the presence and localization of synapses in R7 and R8 photoreceptors. These genetic tools were used to assess how the synaptic profile is affected when axons are forced to target abnormal layers by expressing axon guidance molecules. When R7 axons were mistargeted to the R8-recipient layer, R7s either maintained an R7-like synaptic profile or acquired a similar profile to r8s depending on the overexpressed protein. When R7 axons were redirected to a more superficial medulla layer, the number of presynaptic terminals was reduced. These results indicate that cell-surface molecules are able to dictate synapse loci by changing the axon terminal identity in a partially cell-autonomous manner, but that presynapse formation at specific sites also requires complex interactions between pre- and post-synaptic elements.

  7. System-level design of bacterial cell cycle control

    OpenAIRE

    McAdams, Harley H.; Shapiro, Lucy

    2009-01-01

    Understanding of the cell cycle control logic in Caulobacter has progressed to the point where we now have an integrated view of the operation of an entire bacterial cell cycle system functioning as a state machine. Oscillating levels of a few temporally-controlled master regulator proteins in a cyclical circuit drive cell cycle progression. To a striking degree, the cell cycle regulation is a whole cell phenomenon. Phospho-signaling proteins and proteases dynamically deployed to specific loc...

  8. Helicopter control response types for hover and low-speed near-earth tasks in degraded visual conditions

    Science.gov (United States)

    Blanken, Christopher L.; Hart, Daniel C.; Hoh, Roger H.

    1991-01-01

    The NASA-Ames Vertical Motion Simulator and Dig 1 Computer Image Generator (CIG) have been used to simulate a helicopter cockpit in a degraded visual environment in order to assess several control-response types during low-level flight. CIG visibility was reduced to the point where the horizon and other far-field cues were indiscernible. The control-response types encompassed a rate command, an attitude command/hold, and a translational rate command; piloting tasks were hover, vertical landing, a pirouette, acceleration/deceleration, and a sidestep maneuver. Visual cue ratings with a rate-command response type were initially collected to set the usable cue environment at 3. A rate-command response type provided poor Level 2 handling qualities.

  9. Visualization of Photoexcited Carrier Responses in a Solar Cell Using Optical Pump—Terahertz Emission Probe Technique

    Science.gov (United States)

    Nakanishi, Hidetoshi; Ito, Akira; Takayama, Kazuhisa; Kawayama, Iwao; Murakami, Hironaru; Tonouchi, Masayoshi

    2016-05-01

    We observed photoexcited carrier responses in solar cells excited by femtosecond laser pulses with spatial and temporal resolution using an optical pump-terahertz emission probe technique. We visualized the ultrafast local variation of the intensity of terahertz emission from a polycrystalline silicon solar cell using this technique and clearly observed the change in signals between a grain boundary and the inside of a grain in the solar cell. Further, the time evolution of the pump-probe signals of the polycrystalline and monocrystalline silicon solar cells was observed, and the relaxation times of photoexcited carriers in the emitter layers of crystalline silicon solar cells were estimated using this technique. The estimated relaxation time was consistent with the lifetime of the Auger recombination process that was dominant in heavily doped silicon used as an emitter layer for the silicon solar cells, which is difficult to obtain with photoluminescence method commonly used for the evaluation of solar cells.

  10. Visualization of Fuel Cell Water Transport and Performance Characterization under Freezing Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kandlikar, Satish G. [Rochester Inst. of Technology, Rochester, NY (United States); Lu, Zijie [Rochester Inst. of Technology, Rochester, NY (United States); Rao, Navalgund [Rochester Inst. of Technology, Rochester, NY (United States); Sergi, Jacqueline [Rochester Inst. of Technology, Rochester, NY (United States); Rath, Cody [Rochester Inst. of Technology, Rochester, NY (United States); McDade, Christopher [Rochester Inst. of Technology, Rochester, NY (United States); Trabold, Thomas [General Motors, Honeoye Falls, NY (United States); Owejan, Jon [General Motors, Honeoye Falls, NY (United States); Gagliardo, Jeffrey [General Motors, Honeoye Falls, NY (United States); Allen, Jeffrey [Michigan Technological Univ., Houghton, MI (United States); Yassar, Reza S. [Michigan Technological Univ., Houghton, MI (United States); Medici, Ezequiel [Michigan Technological Univ., Houghton, MI (United States); Herescu, Alexandru [Michigan Technological Univ., Houghton, MI (United States)

    2010-05-30

    In this program, Rochester Institute of Technology (RIT), General Motors (GM) and Michigan Technological University (MTU) have focused on fundamental studies that address water transport, accumulation and mitigation processes in the gas diffusion layer and flow field channels of the bipolar plate. These studies have been conducted with a particular emphasis on understanding the key transport phenomena which control fuel cell operation under freezing conditions.

  11. Multi-platform subsystem for controlling acquisition, visualization and data organization of an NMR Digital Spectrometer: ToRM Console

    International Nuclear Information System (INIS)

    In this work, we present the recent results from the development of the CIERMag NMR Digital Spectrometer - a subsystem for controlling acquisition, visualization and data organization. Some aspects of the architecture and features will be shown, including a demonstration with CPMG method for transversal relaxation time (T2) measurement using the system. With these achievements, ToRM Console is now being prepared to be an MRI scanner in a near future (author)

  12. Laser Ultrasonic System for Surface Crack Visualization in Dissimilar Welds of Control Rod Drive Mechanism Assembly of Nuclear Power Plant

    OpenAIRE

    Yun-Shil Choi; Hyomi Jeong; Jung-Ryul Lee

    2014-01-01

    In this paper, we propose a J-groove dissimilar weld crack visualization system based on ultrasonic propagation imaging (UPI) technology. A full-scale control rod drive mechanism (CRDM) assembly specimen was fabricated to verify the proposed system. An ultrasonic sensor was contacted at one point of the inner surface of the reactor vessel head part of the CRDM assembly. Q-switched laser beams were scanned to generate ultrasonic waves around the weld bead. The localization and sizing of the cr...

  13. Visual feedback facilitates intermanual transfer of the motor control of the dominant arm towards the nondominant arm

    OpenAIRE

    Urra Vicario, Oiane; Casals Gelpi, Alicia; Jané Campos, Raimon

    2015-01-01

    Visual feedback (VF) is applied to recover motor skills after stroke. However, the exact mechanisms underlying the beneficial effects of VF remain unclear, limiting its optimal use in clinical practice. We previously reported that the effect of neural mechanisms triggered by VF is reflected in the upperlimb at the level of the control structure (the set of synergies/corresponding activation coefficients used to perform a task). Here, we hypothesize that VF may facilitate the transfer of...

  14. On a new visualization tool for quantum systems and on a time-optimal control problem for quantum gates

    International Nuclear Information System (INIS)

    Since the foundations of quantum physics have been laid, our knowledge of it never ceased to grow and this field of science naturally split into diverse specialized branches. The first part of this thesis focuses on a problem which concerns all branches of quantum physics, which is the visualization of quantum systems. The non-intuitive aspect of quantum physics justifies a shared desire to visualize quantum systems. In the present work, we develop a method to visualize any operators in these systems, including in particular state operators (density matrices), Hamiltonians and propagators. The method, referred to as DROPS (Discrete Representation of spin OPeratorS), is based on a generalization of Wigner representations, presented in this document. The resulting visualization of an operator A is called its DROPS representation or visualization. We demonstrate its intuitive character by illustrating a series of concepts in nuclear magnetic resonance (NMR) spectroscopy for systems consisting of two spin-1/2 particles. The second part of this thesis is concerned with a problem of optimal control which finds applications in the fields of NMR spectroscopy, medical imagery and quantum computing, to cite a few. The problem of creating a propagator in the shortest amount of time is considered, and the results are extended to solve the closely related problem of creating rotations in the smallest amount of time. The approach used here differs from the previous results on the subject by solving the problem using the Pontryagin's maximum principle and by its detailed consideration of singular controls and trajectories.

  15. Sensorimotor control of gait: A novel approach for the study of the interplay of visual and proprioceptive feedback

    Directory of Open Access Journals (Sweden)

    Panagiotis Artemiadis

    2015-02-01

    Full Text Available Sensorimotor control theories propose that the central nervous system exploits expected sensory consequences generated by motor commands for movement planning, as well as online sensory feedback for comparison with expected sensory feedback for monitoring and correcting, if needed, ongoing motor output. In our study, we tested this theoretical framework by quantifying the functional role of expected versus actual proprioceptive feedback for planning and regulation of gait in humans. We addressed this question by using a novel methodological approach to deliver fast perturbations of the walking surface stiffness, in conjunction with a virtual reality system that provided visual feedback of upcoming changes of surface stiffness. In the "predictable" experimental condition, we asked subjects to learn associating visual feedback of changes in floor stiffness (sand patch during locomotion to quantify kinematic and kinetic changes in gait. In the "unpredictable" experimental condition, we perturbed floor stiffness at unpredictable instances during the gait to characterize the gait-phase dependent strategies in recovering the locomotor cycle. For the "unpredictable" conditions, visual feedback of changes in floor stiffness was absent or inconsistent with tactile and proprioceptive feedback. The investigation of these perturbation-induced effects on legs kinematics revealed that visual feedback of upcoming changes in floor stiffness allows for both early (preparatory and late (post-perturbation changes in leg kinematics. However, when proprioceptive feedback is not available, the early responses do not occur while the late responses are preserved although in a, slightly attenuated form. The methods proposed and the preliminary results of this study open new directions for the investigation of the relative role of visual, tactile, and proprioceptive feedback on gait control, with potential implications for designing novel robot-assisted gait

  16. Influence of enhanced visual feedback on postural control and spinal reflex modulation during stance.

    Science.gov (United States)

    Taube, Wolfgang; Leukel, Christian; Gollhofer, Albert

    2008-07-01

    The present study assessed the influence of visual feedback on stance stability and soleus H-reflex excitability. The centre of pressure (COP) displacement was measured in upright stance on a rigid surface (stable surface) and on a spinning top (unstable surface) while subjects either received "normal" visual feedback (without laser pointer = WLP) or pointed with a laser pointer on a target on the wall (LP). In order to verify that laser pointing influenced visual feedback, two additional experiments were conducted: (1) Subjects performed a finger reaction task which was thought to increase attention and cognitive demands without alteration of the visual feedback. (2) The effect of laser pointing on the wall was compared with pointing at a board, which was attached to the subjects themselves. In this case, the laser point could not serve as a reference for sway because the board moved in synchrony with the body. On stable and unstable surface, COP displacement was reduced in the LP compared to the WLP task (-17 cm +/- 6, P laser pointer targeting on an external reference point. It is argued that altered visual input was responsible for modulating the H-reflex. PMID:18421451

  17. Parasol cell mosaics are unlikely to drive the formation of structured orientation maps in primary visual cortex.

    Science.gov (United States)

    Hore, Victoria R A; Troy, John B; Eglen, Stephen J

    2012-11-01

    The receptive fields of on- and off-center parasol cell mosaics independently tile the retina to ensure efficient sampling of visual space. A recent theoretical model represented the on- and off-center mosaics by noisy hexagonal lattices of slightly different density. When the two lattices are overlaid, long-range Moiré interference patterns are generated. These Moiré interference patterns have been suggested to drive the formation of highly structured orientation maps in visual cortex. Here, we show that noisy hexagonal lattices do not capture the spatial statistics of parasol cell mosaics. An alternative model based upon local exclusion zones, termed as the pairwise interaction point process (PIPP) model, generates patterns that are statistically indistinguishable from parasol cell mosaics. A key difference between the PIPP model and the hexagonal lattice model is that the PIPP model does not generate Moiré interference patterns, and hence stimulated orientation maps do not show any hexagonal structure. Finally, we estimate the spatial extent of spatial correlations in parasol cell mosaics to be only 200-350 μm, far less than that required to generate Moiré interference. We conclude that parasol cell mosaics are too disordered to drive the formation of highly structured orientation maps in visual cortex. PMID:23110776

  18. Wnt-Dependent Control of Cell Polarity in Cultured Cells.

    Science.gov (United States)

    Runkle, Kristin B; Witze, Eric S

    2016-01-01

    The secreted ligand Wnt5a regulates cell polarity and polarized cell movement during development by signaling through the poorly defined noncanonical Wnt pathway. Cell polarity regulates most aspects of cell behavior including the organization of apical/basolateral membrane domains of epithelial cells, polarized cell divisions along a directional plane, and front rear polarity during cell migration. These characteristics of cell polarity allow coordinated cell movements required for tissue formation and organogenesis during embryonic development. Genetic model organisms have been used to identify multiple signaling pathways including Wnt5a that are required to establish cell polarity and regulate polarized cell behavior. However, the downstream signaling events that regulate these complex cellular processes are still poorly understood. The methods below describe assays to study Wnt5a-induced cell polarity in cultured cells, which may facilitate our understanding of these complex signaling pathways. PMID:27590152

  19. Simplified Load-Following Control for a Fuel Cell System

    Science.gov (United States)

    Vasquez, Arturo

    2010-01-01

    A simplified load-following control scheme has been proposed for a fuel cell power system. The scheme could be used to control devices that are important parts of a fuel cell system but are sometimes characterized as parasitic because they consume some of the power generated by the fuel cells.

  20. The relationship between object-control skills, visual-motor integration and gender of grade 1-learners : the NW-CHILD study / Wilmarié du Plessis

    OpenAIRE

    Du Plessis, Wilmarié

    2014-01-01

    Visual-motor integration, visual perception and motor co-ordination contribute to successful academic, school and career life. Literature also indicates that delays in the skills in above mentioned abilities could lead to delays in the mastering of object control skills. Furthermore, due to the developing needs of South Africa, there is a range of socio-economic challenges, and the effects on the above mentioned skills seem to lack development. Due to the possible effect that visual skills ca...

  1. The contribution of exproprioceptive visual information and seat height to the control of the stand-to-sit movement in young and older individuals

    OpenAIRE

    Moraes, R; J. Pereira dos Reis; R.S. Castelli

    2011-01-01

    The purpose of the present study was to analyze the contribution of both exproprioceptive visual information and seat height in the control of stand-to-sit movement in young and older adults. Twelve older and 11 young individuals were invited to sit down on a chair under two seat heights (100% and 80% of the knee-ground distance) and under two visual conditions (with and without the availability of exproprioceptive visual information). Participants wore special goggles that reduced the size o...

  2. O tipo de trajetória não afeta o controle visual da freada em ciclistas El tipo de trayectoria no afecta el control visual de frenada en ciclistas Type of trajectory does not affect the visual control of braking in cyclists

    Directory of Open Access Journals (Sweden)

    Sérgio Tosi Rodrigues

    2012-09-01

    Full Text Available O controle visual da freada foi estudado em ciclistas recreacionais através da manipulação da velocidade no início da freada (baixa, média e alta e da trajetória de aproximação (retilínea e curvilínea da bicicleta em relação a um obstáculo estacionário. A hipótese foi que o tipo de trajetória da bicicleta, de modo exclusivo ou em interação com a velocidade inicial, afetaria a informação visual de tempo para colisão ("tau" margem e sua primeira derivada no tempo ("tau-dot", respectivamente, no início e durante a freada. Os resultados revelaram que a velocidade afetou significativamente "tau" margem, enquanto "tau-dot" manteve-se inalterado independentemente da condição. O tipo de trajetória claramente não afetou o controle visual da freada em ciclistas.El control visual de la frenada fue estudiado en ciclistas recreativos mediante la manipulación de la velocidad (baja, media y alta al principio de la frenada y la trayectoria de aproximación de la bicicleta (rectilínea y curvilínea en relación con un obstáculo fijo. La hipótesis era que el tipo de trayectoria de la bicicleta, de modo exclusivo o en interacción con la velocidad inicial, afectaría la información visual del momento de la colisión (margen "tau" y su primera derivada en el tiempo ("tau-dot", respectivamente, al principio y durante la frenada. Los resultados revelaron que la velocidad afectó significativamente el margen "tau", mientras que el "tau-dot" permaneció inalterado independientemente de su condición. El tipo de trayectoria claramente no afectó el control visual de frenado en los ciclistas.Braking visual control was studied in recreational cyclists through the manipulation of bicycle's velocity at braking initiation (low, medium, and high and approaching trajectory (straight and curved with respect to a stationary obstacle. The hypothesis was that the type of trajectory, exclusively or interacting with initial velocity, would affect time

  3. Software tools for simultaneous data visualization and T cell epitopes and disorder prediction in proteins.

    Science.gov (United States)

    Jandrlić, Davorka R; Lazić, Goran M; Mitić, Nenad S; Pavlović, Mirjana D

    2016-04-01

    We have developed EpDis and MassPred, extendable open source software tools that support bioinformatic research and enable parallel use of different methods for the prediction of T cell epitopes, disorder and disordered binding regions and hydropathy calculation. These tools offer a semi-automated installation of chosen sets of external predictors and an interface allowing for easy application of the prediction methods, which can be applied either to individual proteins or to datasets of a large number of proteins. In addition to access to prediction methods, the tools also provide visualization of the obtained results, calculation of consensus from results of different methods, as well as import of experimental data and their comparison with results obtained with different predictors. The tools also offer a graphical user interface and the possibility to store data and the results obtained using all of the integrated methods in the relational database or flat file for further analysis. The MassPred part enables a massive parallel application of all integrated predictors to the set of proteins. Both tools can be downloaded from http://bioinfo.matf.bg.ac.rs/home/downloads.wafl?cat=Software. Appendix A includes the technical description of the created tools and a list of supported predictors. PMID:26851400

  4. Kinetics of linear rouleaux formation studied by visual monitoring of red cell dynamic organization.

    Science.gov (United States)

    Barshtein, G; Wajnblum, D; Yedgar, S

    2000-05-01

    Red blood cells (RBCs) in the presence of plasma proteins or other macromolecules may form aggregates, normally in rouleaux formations, which are dispersed with increasing blood flow. Experimental observations have suggested that the spontaneous aggregation process involves the formation of linear rouleaux (FLR) followed by formation of branched rouleaux networks. Theoretical models for the spontaneous rouleaux formation were formulated, taking into consideration that FLR may involve both "polymerization," i.e., interaction between two single RBCs (e + e) and the addition of a single RBC to the end of an existing rouleau (e + r), as well as "condensation" between two rouleaux by end-to-end addition (r + r). The present study was undertaken to experimentally examine the theoretical models and their assumptions, by visual monitoring of the spontaneous FLR (from singly dispersed RBC) in plasma, in a narrow gap flow chamber. The results validate the theoretical model, showing that FLR involves both polymerization and condensation, and that the kinetic constants for the above three types of intercellular interactions are the same, i.e., k(ee) = k(er) = k(rr) = k, and for all tested hematocrits (0.625-6%) k < 0.13 +/- 0.03 s(-1). PMID:10777743

  5. Fluorescent Lipids: Functional Parts of Fusogenic Liposomes and Tools for Cell Membrane Labeling and Visualization

    Directory of Open Access Journals (Sweden)

    Christian Kleusch

    2012-01-01

    Full Text Available In this paper a rapid and highly efficient method for controlled incorporation of fluorescent lipids into living mammalian cells is introduced. Here, the fluorescent molecules have two consecutive functions: First, they trigger rapid membrane fusion between cellular plasma membranes and the lipid bilayers of their carrier particles, so called fusogenic liposomes, and second, after insertion into cellular membranes these molecules enable fluorescence imaging of cell membranes and membrane traffic processes. We tested the fluorescent derivatives of the following essential membrane lipids for membrane fusion: Ceramide, sphingomyelin, phosphocholine, phosphatidylinositol-bisphosphate, ganglioside, cholesterol, and cholesteryl ester. Our results show that all probed lipids could more efficiently be incorporated into the plasma membrane of living cells than by using other methods. Moreover, labeling occurred in a gentle manner under classical cell culture conditions reducing cellular stress responses. Staining procedures were monitored by fluorescence microscopy and it was observed that sphingolipids and cholesterol containing free hydroxyl groups exhibit a decreased distribution velocity as well as a longer persistence in the plasma membrane compared to lipids without hydroxyl groups like phospholipids or other artificial lipid analogs. After membrane staining, the fluorescent molecules were sorted into membranes of cell organelles according to their chemical properties and biological functions without any influence of the delivery system.

  6. Standardising visual control devices for tsetse flies: Central and West African species Glossina palpalis palpalis.

    Directory of Open Access Journals (Sweden)

    Dramane Kaba

    Full Text Available BACKGROUND: Glossina palpalis palpalis (G. p. palpalis is one of the principal vectors of sleeping sickness and nagana in Africa with a geographical range stretching from Liberia in West Africa to Angola in Central Africa. It inhabits tropical rain forest but has also adapted to urban settlements. We set out to standardize a long-lasting, practical and cost-effective visually attractive device that would induce the strongest landing response by G. p. palpalis for future use as an insecticide-impregnated tool in area-wide population suppression of this fly across its range. METHODOLOGY/PRINCIPAL FINDINGS: Trials were conducted in wet and dry seasons in the Ivory Coast, Cameroon, the Democratic Republic of Congo and Angola to measure the performance of traps (biconical, monoconical and pyramidal and targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used as a practical enumerator at these remote locations to compare landing efficiencies of devices. Independent of season and country, both phthalogen blue-black and blue-black-blue 1 m(2 targets covered with adhesive film proved to be as good as traps in phthalogen blue or turquoise blue for capturing G. p. palpalis. Trap efficiency varied (8-51%. There was no difference between the performance of blue-black and blue-black-blue 1 m(2 targets. Baiting with chemicals augmented the overall performance of targets relative to traps. Landings on smaller phthalogen blue-black 0.25 m(2 square targets were not significantly different from either 1 m(2 blue-black-blue or blue-black square targets. Three times more flies were captured per unit area on the smaller device. CONCLUSIONS/SIGNIFICANCE: Blue-black 0.25 m(2 cloth targets show promise as simple cost effective devices for management of G. p. palpalis as they can be used for both control when impregnated with insecticide and for

  7. Standardizing Visual Control Devices for Tsetse Flies: East African Species Glossina swynnertoni

    Science.gov (United States)

    Mramba, Furaha; Oloo, Francis; Byamungu, Mechtilda; Kröber, Thomas; McMullin, Andrew; Mihok, Steve; Guerin, Patrick M.

    2013-01-01

    Background Here we set out to standardize long-lasting, visually-attractive devices for Glossina swynnertoni, a vector of both human and animal trypanosomiasis in open savannah in Tanzania and Kenya, and in neighbouring conservation areas used by pastoralists. The goal was to determine the most practical device/material that would induce the strongest landing response in G. swynnertoni for use in area-wide population suppression of this fly with insecticide-impregnated devices. Methods and Findings Trials were conducted in wet and dry seasons in the Serengeti and Maasai Mara to measure the performance of traps and targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used as a simple enumerator at these remote locations to compare trapping efficiencies of devices. Independent of season or presence of chemical baits, targets in phthalogen blue or turquoise blue cloth with adhesive film were the best devices for capturing G. swynnertoni in all situations, catching up to 19 times more flies than pyramidal traps. Baiting with chemicals did not affect the relative performance of devices. Fly landings were two times higher on 1 m2 blue-black targets as on pyramidal traps when equivalent areas of both were covered with adhesive film. Landings on 1 m2 blue-black targets were compared to those on smaller phthalogen blue 0.5 m2 all-blue or blue-black-blue cloth targets, and to landings on all-blue plastic 0.32–0.47 m2 leg panels painted in phthalogen blue. These smaller targets and leg panels captured equivalent numbers of G. swynnertoni per unit area as bigger targets. Conclusions Leg panels and 0.5 m2 cloth targets show promise as cost effective devices for management of G. swynnertoni as they can be used for both control (insecticide-impregnated cloth) and for sampling (rigid plastic with insect glue or adhesive film) of populations. PMID:23469299

  8. Visualization and measurement of ATP levels in living cells replicating hepatitis C virus genome RNA.

    Directory of Open Access Journals (Sweden)

    Tomomi Ando

    Full Text Available Adenosine 5'-triphosphate (ATP is the primary energy currency of all living organisms and participates in a variety of cellular processes. Although ATP requirements during viral lifecycles have been examined in a number of studies, a method by which ATP production can be monitored in real-time, and by which ATP can be quantified in individual cells and subcellular compartments, is lacking, thereby hindering studies aimed at elucidating the precise mechanisms by which viral replication energized by ATP is controlled. In this study, we investigated the fluctuation and distribution of ATP in cells during RNA replication of the hepatitis C virus (HCV, a member of the Flaviviridae family. We demonstrated that cells involved in viral RNA replication actively consumed ATP, thereby reducing cytoplasmic ATP levels. Subsequently, a method to measure ATP levels at putative subcellular sites of HCV RNA replication in living cells was developed by introducing a recently-established Förster resonance energy transfer (FRET-based ATP indicator, called ATeam, into the NS5A coding region of the HCV replicon. Using this method, we were able to observe the formation of ATP-enriched dot-like structures, which co-localize with non-structural viral proteins, within the cytoplasm of HCV-replicating cells but not in non-replicating cells. The obtained FRET signals allowed us to estimate ATP concentrations within HCV replicating cells as ∼5 mM at possible replicating sites and ∼1 mM at peripheral sites that did not appear to be involved in HCV replication. In contrast, cytoplasmic ATP levels in non-replicating Huh-7 cells were estimated as ∼2 mM. To our knowledge, this is the first study to demonstrate changes in ATP concentration within cells during replication of the HCV genome and increased ATP levels at distinct sites within replicating cells. ATeam may be a powerful tool for the study of energy metabolism during replication of the viral genome.

  9. Multi-sensor data fusion in sensor-based control: application to multi-camera visual servoing

    OpenAIRE

    Kermorgant, Olivier; Chaumette, F.

    2011-01-01

    A low-level sensor fusion scheme is presented for the positioning of a multi-sensor robot. This non-hierarchical framework can be used for robot arms or other velocity- controlled robots, and is part of the task function approach. A stability analysis is presented for the general case, then several control laws illustrate the versatility of the framework. This approach is applied to the multi-camera eye-in-hand/eye- to-hand configuration in visual servoing. Experimental results point out the ...

  10. Treatment of one case of cerebral palsy combined with posterior visual pathway injury using autologous bone marrow mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Li Min

    2012-05-01

    Full Text Available Abstract Background Cerebral palsy is currently one of the major diseases that cause severe paralysis of the nervous system in children; approximately 9–30% of cerebral palsy patients are also visually impaired, for which no effective treatment is available. Bone marrow mesenchymal stem cells (BMSCs have very strong self-renewal, proliferation, and pluripotent differentiation potentials. Therefore, autologous BMSC transplantation has become a novel method for treating cerebral palsy. Methods An 11-year-old boy had a clear history of dystocia and asphyxia after birth; at the age of 6 months, the family members observed that his gaze roamed and noted that he displayed a lack of attention. A brain MRI examination at the age of 7 years showed that the child had cerebral palsy with visual impairment (i.e., posterior visual pathway injury. The patient was hospitalized for 20 days and was given four infusions of intravenous autologous BMSCs. Before transplantation and 1, 6, and 12 months after transplantation, a visual evoked potential test, an electrocardiogram, routine blood tests, and liver and kidney function tests were performed. Results The patient did not have any adverse reactions during hospitalization or postoperative follow-up. After discharge, the patient could walk more smoothly than he could before transplantation; furthermore, his vision significantly improved 6 months after transplantation, which was also supported by the electrophysiological examinations. Conclusions The clinical application of BMSCs is effective for improving vision in a patient with cerebral palsy combined with visual impairment.

  11. The nucleus of the optic tract. Its function in gaze stabilization and control of visual-vestibular interaction

    Science.gov (United States)

    Cohen, B.; Reisine, H.; Yokota, J. I.; Raphan, T.

    1992-01-01

    1. Electrical stimulation of the nucleus of the optic tract (NOT) induced nystagmus and after-nystagmus with ipsilateral slow phases. The velocity characteristics of the nystagmus were similar to those of the slow component of optokinetic nystagmus (OKN) and to optokinetic after-nystagmus (OKAN), both of which are produced by velocity storage in the vestibular system. When NOT was destroyed, these components disappeared. This indicates that velocity storage is activated from the visual system through NOT. 2. Velocity storage produces compensatory eye-in-head and head-on-body movements through the vestibular system. The association of NOT with velocity storage implies that NOT helps stabilize gaze in space during both passive motion and active locomotion in light with an angular component. It has been suggested that "vestibular-only" neurons in the vestibular nuclei play an important role in generation of velocity storage. Similarities between the rise and fall times of eye velocity during OKN and OKAN to firing rates of vestibular-only neurons suggest that these cells may receive their visual input through NOT. 3. One NOT was injected with muscimol, a GABAA agonist. Ipsilateral OKN and OKAN were lost, suggesting that GABA, which is an inhibitory transmitter in NOT, acts on projection pathways to the brain stem. A striking finding was that visual suppression and habituation of contralateral slow phases of vestibular nystagmus were also abolished after muscimol injection. The latter implies that NOT plays an important role in producing visual suppression of the VOR and habituating its time constant. 4. Habituation is lost after nodulus and uvula lesions and visual suppression after lesions of the flocculus and paraflocculus. We postulate that the disappearance of vestibular habituation and of visual suppression of vestibular responses after muscimol injections was due to dysfacilitation of the prominent NOT-inferior olive pathway, inactivating climbing fibers from

  12. Visualization of radiation-induced cell cycle-associated events in tumor cells expressing the fusion protein of Azami Green and the destruction box of human Geminin

    International Nuclear Information System (INIS)

    Ionizing radiation (IR) influences cell cycle-associated events in tumor cells. We expressed the fusion protein of Azami Green (AG) and the destruction box plus nuclear localization signal of human Geminin, an inhibitor of DNA replication licensing factor, in oral tumor cells. This approach allowed us to visualize G2 arrest in living cells following irradiation. The combination of time-lapse imaging analysis allowed us to observe the nuclear envelope break down (NEBD) at early M phase, and disappearance of fluorescence (DF) at the end of M phase. The duration from NEBD to DF was not much affected in irradiated cells; however, most of daughter cells harbored double-strand breaks. Complete DF was also observed in cells exhibiting abnormal mitosis or cytokinesis. We conclude that the fluorescent Geminin probe could function as a stable cell cycle indicator irrespective of genome integrity.

  13. Novel technique for visualizing primordial germ cells in sturgeons (Acipenser ruthenus, A. gueldenstaedtii, A. baerii, and Huso huso).

    Science.gov (United States)

    Saito, Taiju; Psenicka, Martin

    2015-10-01

    Primordial germ cells (PGCs) are the origin of all germ cells in developing embryos. In the sturgeon embryo, PGCs develop from the vegetal hemisphere, which mainly acts as an extraembryonic source of nutrition. Current methods for studying sturgeon PGCs require either killing the fish or using costly and time-consuming histological procedures. Here, we demonstrate that visualization of sterlet (Acipenser ruthenus>) PGCs in vivo is feasible by simply labeling the vegetal hemisphere with fluorescein isothiocyanate (FITC)-dextran. We injected FITC-dextrans, with molecular weights varying between 10 000 and 2 000 000, into the vegetal pole of 1- to 4-cell stage embryos. At the neurula to tail-bud developmental stages, FITC-positive PGC-like cells appeared ventrally around the developing tail bud in the experimental group that received a high-molecular-weight FITC-dextran. The highest average number of FITC-positive PGC-like cells was observed in embryos injected with FITC-dextran having a molecular weight of 500 000 (FD-500). The pattern of migration of the labeled cells was identical to that of PGCs, clearly indicating that the FITC-positive PGC-like cells were PGCs. Labeled vegetal cells, except for the PGCs, were digested and excreted before the embryos starting feeding. FITC-labeled PGCs were observed in the developing gonads of fish for at least 3 mo after injection. We also found that FD-500 could be used to visualize PGCs in other sturgeon species. To the best of our knowledge, this report is the first to demonstrate in any animal species that PGCs can be visualized in vivo for a long period by the injection of a simple reagent. PMID:26134864

  14. Self-Modification Technique for the Control of Eating Behavior for the Visually Handicapped.

    Science.gov (United States)

    Snoy, Mary T.; van Benten, Letitia

    1978-01-01

    A ten-week study was done of four visually handicapped overweight adolescents (ages 15-19 years) in a residential school to evaluate the efficacy of an operant conditioning technique designed to promote weight loss by altering eating habits. (Author/DLS)

  15. Visual-Perceptual Abilities in Healthy Controls, Depressed Patients, and Schizophrenia Patients

    Science.gov (United States)

    Cavezian, Celine; Danckert, James; Lerond, Jerome; Dalery, Jean; d'Amato, Thierry; Saoud, Mohamed

    2007-01-01

    Previous studies have suggested a right hemineglect in schizophrenia, however few assessed possible visual-perceptual implication in this lateralized anomaly. A manual line bisection without (i.e., lines presented on their own) or with a local cueing paradigm (i.e., a number placed at one or both ends of the line) and the Motor-free Visual…

  16. Comparison between numerical simulation and visualization experiment on water behavior in single straight flow channel polymer electrolyte fuel cells

    Science.gov (United States)

    Masuda, Hiromitsu; Ito, Kohei; Oshima, Toshihiro; Sasaki, Kazunari

    A relationship between a flooding and a cell voltage drop for polymer electrolyte fuel cell was investigated experimentally and numerically. A visualization cell, which has single straight gas flow channel (GFC) and observation window, was fabricated to visualize the flooding in GFC. We ran the cell with changing operation condition, and measured the time evolution of cell voltage and took the images of cathode GFC. Considering the operation condition, we executed a developed numerical simulation, which is based on multiphase mixture model with a formulation on water transport through the surface of polymer electrolyte membrane and the interface of gas diffusion layer/GFC. As a result in experiment, we found that the cell voltage decreased with time and this decrease was accelerated by larger current and smaller air flow rate. Our simulation succeeded to demonstrate this trend of cell voltage. In experiment, we also found that the water flushing in GFC caused an immediate voltage change, resulting in voltage recovery or electricity generation stop. Although our simulation could not replicate this immediate voltage change, the supersaturated area obtained by our simulation well corresponded to fogging area appeared on the window surface in the GFC.

  17. Hilar mossy cell circuitry controlling dentate granule cell excitability

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    Seiichiro Jinde

    2013-02-01

    Full Text Available Glutamatergic hilar mossy cells of the dentate gyrus can either excite or inhibit distant granule cells, depending on whether their direct excitatory projections to granule cells or their projections to local inhibitory interneurons dominate. However, it remains controversial whether the net effect of mossy cell loss is granule cell excitation or inhibition. Clarifying this controversy has particular relevance to temporal lobe epilepsy, which is marked by dentate granule cell hyperexcitability and extensive loss of dentate hilar mossy cells. Two diametrically opposed hypotheses have been advanced to explain this granule cell hyperexcitability – the “dormant basket cell” and the “irritable mossy cell” hypotheses. The “dormant basket cell” hypothesis proposes that mossy cells normally exert a net inhibitory effect on granule cells and therefore their loss causes dentate granule cell hyperexcitability. The “irritable mossy cell” hypothesis takes the opposite view that mossy cells normally excite granule cells and that the surviving mossy cells in epilepsy increase their activity, causing granule cell excitation. The inability to eliminate mossy cells selectively has made it difficult to test these two opposing hypotheses. To this end, we developed a transgenic toxin-mediated, mossy cell-ablation mouse line. Using these mutants, we demonstrated that the extensive elimination of hilar mossy cells causes granule cell hyperexcitability, although the mossy cell loss observed appeared insufficient to cause clinical epilepsy. In this review, we focus on this topic and also suggest that different interneuron populations may mediate mossy cell-induced translamellar lateral inhibition and intralamellar recurrent inhibition. These unique local circuits in the dentate hilar region may be centrally involved in the functional organization of the dentate gyrus.

  18. Genetic control and identification of QTLs associated with visual quality traits of field pea (Pisum sativum L.).

    Science.gov (United States)

    Ubayasena, Lasantha; Bett, Kirstin; Tar'an, Bunyamin; Warkentin, Thomas

    2011-04-01

    Visual quality of field pea (Pisum sativum L.) is one of the most important determinants of the market value of the harvested crop. Seed coat color, seed shape, and seed dimpling are the major components of visual seed quality of field pea and are considered as important breeding objectives. The objectives of this research were to study the genetics and to identify quantitative trait loci (QTLs) associated with seed coat color, seed shape, and seed dimpling of green and yellow field peas. Two recombinant inbred line populations (RILs) consisting of 120 and 90 lines of F(5)-derived F(7) (F(5:7)) yellow pea (P. sativum 'Alfetta' × P. sativum 'CDC Bronco') and green pea (P. sativum 'Orb' × P. sativum 'CDC Striker'), respectively, were evaluated over two years at two locations in Saskatchewan, Canada. Quantitative inheritance with polygenic control and transgressive segregation were observed for all visual quality traits studied. All 90 RILs of the green pea population and 92 selected RILs from the yellow pea population were screened using AFLP and SSR markers and two linkage maps were developed. Nine QTLs controlling yellow seed lightness, 3 for yellow seed greenness, 15 for seed shape, and 9 for seed dimpling were detected. Among them, five QTLs located on LG II, LG IV, and LG VII were consistent in at least two environments. The QTLs and their associated markers will be useful tools to assist pea breeding programs attempting to pyramid positive alleles for the traits. PMID:21491970

  19. Visualization and quantitative analysis of extrachromosomal telomere-repeat DNA in individual human cells by Halo-FISH.

    Science.gov (United States)

    Komosa, Martin; Root, Heather; Meyn, M Stephen

    2015-02-27

    Current methods for characterizing extrachromosomal nuclear DNA in mammalian cells do not permit single-cell analysis, are often semi-quantitative and frequently biased toward the detection of circular species. To overcome these limitations, we developed Halo-FISH to visualize and quantitatively analyze extrachromosomal DNA in single cells. We demonstrate Halo-FISH by using it to analyze extrachromosomal telomere-repeat (ECTR) in human cells that use the Alternative Lengthening of Telomeres (ALT) pathway(s) to maintain telomere lengths. We find that GM847 and VA13 ALT cells average ∼80 detectable G/C-strand ECTR DNA molecules/nucleus, while U2OS ALT cells average ∼18 molecules/nucleus. In comparison, human primary and telomerase-positive cells contain 300), range widely in length (200 kb) and are composed of primarily G- or C-strand telomere-repeat DNA. Halo-FISH enables, for the first time, the simultaneous analysis of ECTR DNA and chromosomal telomeres in a single cell. We find that ECTR DNA comprises ∼15% of telomere-repeat DNA in GM847 and VA13 cells, but <4% in U2OS cells. In addition to its use in ALT cell analysis, Halo-FISH can facilitate the study of a wide variety of extrachromosomal DNA in mammalian cells. PMID:25662602

  20. Alpha-bungarotoxin binding to target cell in a developing visual system by carboxylated nanodiamond

    Science.gov (United States)

    Liu, Kuang-Kai; Chen, Mei-Fang; Chen, Po-Yi; Lee, Tony J. F.; Cheng, Chia-Liang; Chang, Chia-Ching; Ho, Yen-Peng; Chao, Jui-I.

    2008-05-01

    Biological molecules conjugating with nanoparticles are valuable for applications including bio-imaging, bio-detection, and bio-sensing. Nanometer-sized diamond particles have excellent electronic and chemical properties for bio-conjugation. In this study, we manipulated the carboxyl group produced on the surface of nanodiamond (carboxylated nanodiamond, cND) for conjugating with alpha-bungarotoxin (α-BTX), a neurotoxin derived from Bungarus multicinctus with specific blockade of alpha7-nicotinic acetylcholine receptor (α7-nAChR). The electrostatic binding of cND-α-BTX was mediated by the negative charge of the cND and the positive charge of the α-BTX in physiological pH conditions. Sodium dodecyl sulfate-polyacrylamide gel analysis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI/TOF-MS) spectra displayed that α-BTX proteins were conjugated with cND particles via non-covalent bindings. The green fluorescence of the cND particles combining with the red fluorescence of tetramethylrhodamine-labeled α-BTX presented a yellow color at the same location, which indicated that α-BTX proteins were conjugated with cND particles. Xenopus laevis's oocytes expressed the human α7-nAChR proteins by microinjection with α7-nAChR mRNA. The cND-α-BTX complexes were bound to α7-nAChR locating on the cell membrane of oocytes and human lung A549 cancer cells analyzed by laser scanning confocal microscopy. The choline-evoked α7-nAChR-mediated inward currents of the oocytes were blocked by cND-α-BTX complexes in a concentration-dependent manner using two-electrode voltage-clamp recording. Furthermore, the fluorescence intensity of cND-α-BTX binding on A549 cells could be quantified by flow cytometry. These results indicate that cND-conjugated α-BTX still preserves its biological activity in blocking the function of α7-nAChR, and provide a visual system showing the binding of α-BTX to α7-nAChR.

  1. Alpha-bungarotoxin binding to target cell in a developing visual system by carboxylated nanodiamond

    International Nuclear Information System (INIS)

    Biological molecules conjugating with nanoparticles are valuable for applications including bio-imaging, bio-detection, and bio-sensing. Nanometer-sized diamond particles have excellent electronic and chemical properties for bio-conjugation. In this study, we manipulated the carboxyl group produced on the surface of nanodiamond (carboxylated nanodiamond, cND) for conjugating with alpha-bungarotoxin (α-BTX), a neurotoxin derived from Bungarus multicinctus with specific blockade of alpha7-nicotinic acetylcholine receptor (α7-nAChR). The electrostatic binding of cND-α-BTX was mediated by the negative charge of the cND and the positive charge of the α-BTX in physiological pH conditions. Sodium dodecyl sulfate-polyacrylamide gel analysis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI/TOF-MS) spectra displayed that α-BTX proteins were conjugated with cND particles via non-covalent bindings. The green fluorescence of the cND particles combining with the red fluorescence of tetramethylrhodamine-labeled α-BTX presented a yellow color at the same location, which indicated that α-BTX proteins were conjugated with cND particles. Xenopus laevis's oocytes expressed the human α7-nAChR proteins by microinjection with α7-nAChR mRNA. The cND-α-BTX complexes were bound to α7-nAChR locating on the cell membrane of oocytes and human lung A549 cancer cells analyzed by laser scanning confocal microscopy. The choline-evoked α7-nAChR-mediated inward currents of the oocytes were blocked by cND-α-BTX complexes in a concentration-dependent manner using two-electrode voltage-clamp recording. Furthermore, the fluorescence intensity of cND-α-BTX binding on A549 cells could be quantified by flow cytometry. These results indicate that cND-conjugated α-BTX still preserves its biological activity in blocking the function of α7-nAChR, and provide a visual system showing the binding of α-BTX to α7-nAChR

  2. Visualizing pancreatic {beta}-cell mass with [{sup 11}C]DTBZ

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, Norman Ray [Department of Radiology, Columbia University Medical School, New York, NY 10032 (United States); Souza, Fabiola [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States); Witkowski, Piotr [Department of Medicine, Columbia University Medical School, New York, NY 10032 (United States); Maffei, Antonella [Institute of Genetics and Biophysics ' Adriano Buzzati-Traverso' , CNR, Naples 80131 (Italy); Raffo, Anthony [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States); Herron, Alan [Center for Comparative Medicine and The Department of Pathology, Baylor College of Medicine, Houston, TX 77030 (United States); Kilbourn, Michael [Department of Radiology, University of Michigan, Ann Arbor, MI 48109-0638 (United States); Jurewicz, Agata [Department of Radiology, Columbia University Medical School, New York, NY 10032 (United States); Herold, Kevan [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States); Liu, Eric [Diabetes Branch, NIDDK, National Institutes of Health, Bethesda, MD 20854 (United States); Hardy, Mark Adam [Department of Medicine, Columbia University Medical School, New York, NY 10032 (United States); Van Heertum, Ronald [Department of Radiology, Columbia University Medical School, New York, NY 10032 (United States); Harris, Paul Emerson [Department of Surgery, Columbia University Medical School, New York, NY 10032 (United States)]. E-mail: peh1@columbia.edu

    2006-10-15

    {beta}-Cell mass (BCM) influences the total amount of insulin secreted, varies by individual and by the degree of insulin resistance, and is affected by physiologic and pathologic conditions. The islets of Langerhans, however, appear to have a reserve capacity of insulin secretion and, overall, assessments of insulin and blood glucose levels remain poor measures of BCM, {beta}-cell function and progression of diabetes. Thus, novel noninvasive determinations of BCM are needed to provide a quantitative endpoint for novel therapies of diabetes, islet regeneration and transplantation. Built on previous gene expression studies, we tested the hypothesis that the targeting of vesicular monoamine transporter 2 (VMAT2), which is expressed by {beta} cells, with [{sup 11}C]dihydrotetrabenazine ([{sup 11}C]DTBZ), a radioligand specific for VMAT2, and the use of positron emission tomography (PET) can provide a measure of BCM. In this report, we demonstrate decreased radioligand uptake within the pancreas of Lewis rats with streptozotocin-induced diabetes relative to their euglycemic historical controls. These studies suggest that quantitation of VMAT2 expression in {beta} cells with the use of [{sup 11}C]DTBZ and PET represents a method for noninvasive longitudinal estimates of changes in BCM that may be useful in the study and treatment of diabetes.

  3. Biological cell controllable patch-clamp microchip

    Science.gov (United States)

    Penmetsa, Siva; Nagrajan, Krithika; Gong, Zhongcheng; Mills, David; Que, Long

    2010-12-01

    A patch-clamp (PC) microchip with cell sorting and positioning functions is reported, which can avoid drawbacks of random cell selection or positioning for a PC microchip. The cell sorting and positioning are enabled by air bubble (AB) actuators. AB actuators are pneumatic actuators, in which air pressure is generated by microheaters within sealed microchambers. The sorting, positioning, and capturing of 3T3 cells by this type of microchip have been demonstrated. Using human breast cancer cells MDA-MB-231 as the model, experiments have been demonstrated by this microchip as a label-free technical platform for real-time monitoring of the cell viability.

  4. Behavior of a metabolic cycling population at the single cell level as visualized by fluorescent gene expression reporters.

    Directory of Open Access Journals (Sweden)

    Sunil Laxman

    Full Text Available BACKGROUND: During continuous growth in specific chemostat cultures, budding yeast undergo robust oscillations in oxygen consumption that are accompanied by highly periodic changes in transcript abundance of a majority of genes, in a phenomenon called the Yeast Metabolic Cycle (YMC. This study uses fluorescent reporters of genes specific to different YMC phases in order to visualize this phenomenon and understand the temporal regulation of gene expression at the level of individual cells within the cycling population. METHODOLOGY: Fluorescent gene expression reporters for different phases of the YMC were constructed and stably integrated into the yeast genome. Subsequently, these reporter-expressing yeast were used to visualize YMC dynamics at the individual cell level in cultures grown in a chemostat or in a microfluidics platform under varying glucose concentrations, using fluorescence microscopy and quantitative Western blots. CONCLUSIONS: The behavior of single cells within a metabolic cycling population was visualized using phase-specific fluorescent reporters. The reporters largely recapitulated genome-specified mRNA expression profiles. A significant fraction of the cell population appeared to exhibit basal expression of the reporters, supporting the hypothesis that there are at least two distinct subpopulations of cells within the cycling population. Although approximately half of the cycling population initiated cell division in each permissive window of the YMC, metabolic synchrony of the population was maintained. Using a microfluidics platform we observed that low glucose concentrations appear to be necessary for metabolic cycling. Lastly, we propose that there is a temporal window in the oxidative growth phase of the YMC where the cycling population segregates into at least two subpopulations, one which will enter the cell cycle and one which does not.

  5. Mitotic Control of Cancer Stem Cells

    OpenAIRE

    Venere, Monica; Miller, Tyler E.; Rich, Jeremy N.

    2013-01-01

    Cancer stem cells are self-renewing, tumorigenic cells at the apex of tumor hierarchies, and postulated to be quiescent in many tumor types. This issue of Cancer Discovery highlights a study that links the presentation of kinetochores within mitosis to an essential requirement for BUB1B/BubR1, broadening our understanding of the cell-cycle machinery in cancer stem cells.

  6. Myelin repair by Schwann cells in the regenerating goldfish visual pathway: regional patterns revealed by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nona, S.N.; Stafford, C.A.; Cronly-Dillon, J.R. (Manchester Univ. (United Kingdom). Inst. of Science and Technology); Duncan, A. (Guy' s Hospital, London (United Kingdom). Dept. of Anatomy); Scholes, J. (University Coll., London (United Kingdom))

    1994-07-01

    In the regenerating goldfish optic nerves, Schwann cells of unknown origin reliably infiltrate the lesion site forming a band of peripheral-type myelinating tissue by 1-2 months, sharply demarcated form the adjacent new CNS myelin. To investigate this effect, we have interfered with cell proliferation by locally X-irradiating the fish visual pathway 24 h after the lesion. As assayed by immunohistochemistry and EM, irradiation retards until 6 months formation of new myelin by Schwann cells at the lesion site, and virtually abolishes oligodendrocyte myelination distally, but has little or no effect on nerve fibre regrowth. Optic nerve astrocyte processes normally fail to re-infiltrate the lesion, but re-occupy it after irradiation, suggesting that they are normally excluded by early cell proliferation at this site. Moreover, scattered myelinating Schwann cells also appear in the oligodendrocyte-depleted distal optic nerve after irradiation, although only as far as the optic tract. (Author).

  7. Treatment of one case of cerebral palsy combined with posterior visual pathway injury using autologous bone marrow mesenchymal stem cells

    OpenAIRE

    Li Min; Yu Aixue; Zhang Fangfang; Dai GuangHui; Cheng Hongbin; Wang Xiaodong; An Yihua

    2012-01-01

    Abstract Background Cerebral palsy is currently one of the major diseases that cause severe paralysis of the nervous system in children; approximately 9–30% of cerebral palsy patients are also visually impaired, for which no effective treatment is available. Bone marrow mesenchymal stem cells (BMSCs) have very strong self-renewal, proliferation, and pluripotent differentiation potentials. Therefore, autologous BMSC transplantation has become a novel method for treating cerebral palsy. Methods...

  8. Visualization study of motion and deformation of red blood cells in a microchannel with straight, divergent and convergent sections

    OpenAIRE

    Chen, Bin; Guo, Fang; Xiang, Hao

    2011-01-01

    The size of red blood cells (RBC) is on the same order as the diameter of microvascular vessels. Therefore, blood should be regarded as a two-phase flow system of RBCs suspended in plasma rather than a continuous medium of microcirculation. It is of great physiological and pathological significance to investigate the effects of deformation and aggregation of RBCs on microcirculation. In this study, a visualization experiment was conducted to study the microcirculatory behavior of RBCs in susp...

  9. Relationship between Reaction Time, Fine Motor Control, and Visual-Spatial Perception on Vigilance and Visual-Motor Tasks in 22q11.2 Deletion Syndrome

    Science.gov (United States)

    Howley, Sarah A.; Prasad, Sarah E.; Pender, Niall P.; Murphy, Kieran C.

    2012-01-01

    22q11.2 Deletion Syndrome (22q11DS) is a common microdeletion disorder associated with mild to moderate intellectual disability and specific neurocognitive deficits, particularly in visual-motor and attentional abilities. Currently there is evidence that the visual-motor profile of 22q11DS is not entirely mediated by intellectual disability and…

  10. Hierarchical structural control of visual properties in self-assembled photonic-plasmonic pigments

    OpenAIRE

    Koay, Natalie; Burgess, Ian B.; Kay, Theresa M.; Nerger, Bryan A.; Miles-Rossouw, Malaika; Shirman, Tanya; Vu, Thy L.; England, Grant; Phillips, Katherine R.; Utech, Stefanie; Vogel, Nicolas; Kolle, Mathias; Aizenberg, Joanna

    2014-01-01

    We present a simple one-pot co-assembly method for the synthesis of hierarchically structured pigment particles consisting of silica inverse-opal bricks that are doped with plasmonic absorbers. We study the interplay between the plasmonic and photonic resonances and their effect on the visual appearance of macroscopic collections of photonic bricks that are distributed in randomized orientations. Manipulating the pore geometry tunes the wavelength- and angle-dependence of the scattering profi...

  11. An Enhanced Intelligent Handheld Instrument with Visual Servo Control for 2-DOF Hand Motion Error Compensation

    OpenAIRE

    Yan Naing Aye; Su Zhao; Wei Tech Ang

    2013-01-01

    The intelligent handheld instrument, ITrem2, enhances manual positioning accuracy by cancelling erroneous hand movements and, at the same time, provides automatic micromanipulation functions. Visual data is acquired from a high speed monovision camera attached to the optical surgical microscope and acceleration measurements are acquired from the inertial measurement unit (IMU) on board ITrem2. Tremor estimation and canceling is implemented via Band-limited Multiple Fourier Linear Combiner (BM...

  12. Stepped care for depression and anxiety in visually impaired older adults: multicentre randomised controlled trial

    OpenAIRE

    van der Aa, Hilde P. A.; van Rens, Ger H. M. B.; Comijs, Hannie C; Margrain, Tom H; Gallindo-Garre, Francisca; Twisk, Jos W. R.; van Nispen, Ruth M A

    2015-01-01

    Study question Is stepped care compared with usual care effective in preventing the onset of major depressive, dysthymic, and anxiety disorders in older people with visual impairment (caused mainly by age related eye disease) and subthreshold depression and/or anxiety? Methods 265 people aged ≥50 were randomly assigned to a stepped care programme plus usual care (n=131) or usual care only (n=134). Supervised occupational therapists, social workers, and psychologists from low vision rehabilita...

  13. Local GABA Circuit Control of Experience-Dependent Plasticity in Developing Visual Cortex

    OpenAIRE

    Hensch, Takao K.; Fagiolini, Michela; Mataga, Nobuko; Stryker, Michael P.; Baekkeskov, Steinunn; Kash, Shera F.

    1998-01-01

    Sensory experience in early life shapes the mammalian brain. An impairment in the activity-dependent refinement of functional connections within developing visual cortex was identified here in a mouse model. Gene-targeted disruption of one isoform of glutamic acid decarboxylase prevented the competitive loss of responsiveness to an eye briefly deprived of vision, without affecting cooperative mechanisms of synapse modification in vitro. Selective, use-dependent enhancement of fast intracortic...

  14. Standardizing Visual Control Devices for Tsetse Flies: East African Species Glossina swynnertoni

    OpenAIRE

    Mramba, Furaha; Oloo, Francis; Byamungu, Mechtilda; Kröber, Thomas; McMullin, Andrew; Mihok, Steve; Guerin, Patrick M.

    2013-01-01

    Background Here we set out to standardize long-lasting, visually-attractive devices for Glossina swynnertoni, a vector of both human and animal trypanosomiasis in open savannah in Tanzania and Kenya, and in neighbouring conservation areas used by pastoralists. The goal was to determine the most practical device/material that would induce the strongest landing response in G. swynnertoni for use in area-wide population suppression of this fly with insecticide-impregnated devices. Methods and Fi...

  15. Visual function and fine-motor control in small-for-gestational age infants Função visual e controle motor apendicular em lactentes pequenos para a idade gestacional

    OpenAIRE

    Heloisa G.R.G. Gagliardo; VANDA M. G. GONÇALVES; Maria Cecilia M.P. Lima; Maria de Fatima de C. Francozo; Abimael Aranha Netto

    2004-01-01

    OBJECTIVE: To compare visual function and fine-motor control of full-term infants small-for-gestational age (SGA) and appropriate for gestational age (AGA), in the first three months. METHOD: We evaluated prospectively 31 infants in the 1st month; 33 in the 2nd and 34 infants in the 3rd month, categorized as full-term; birth weight less than 10th percentile for SGA and 25th to 90th percentile for the AGA group. Genetic syndromes, infections, multiple congenital malformations were excluded. Th...

  16. ENIQ-qualified visual examinations by means of a remote controlled submarine

    Energy Technology Data Exchange (ETDEWEB)

    Tsvetkov, Elenko; Heinsius, Jan [AREVA GmbH, Erlangen (Germany)

    2015-07-15

    Remote visual examination is one of the most important methods for non- destructive in-service inspections of primary components in nuclear power plants. It features two main advantages: the short examination duration and the fast interpretation of results. AREVA offers operators of nuclear power plants the ''SUSI 420 HD'' SUbmarine System for Inspections to perform ENIQ-qualified visual examinations during outages without working on the critical path and causing any delay in the time schedule. The system is a remotely operated manipulator equipped with a high definition camera. With a weight of only 25 kg, there is no need for a crane to put the submarine into water. More-over, nor the use of the refueling machine neither the auxiliary bridge is required. In this way the visual examination can be performed in parallel to other activities which are on the critical path. The article takes a closer look at the essential parameters: illumination, examination distance, viewing angle, scanning speed, positioning accuracy and sizing of indications. It describes how the system can fulfill these parameters through some adaptations.

  17. ENIQ-qualified visual examinations by means of a remote controlled submarine

    International Nuclear Information System (INIS)

    Remote visual examination is one of the most important methods for non- destructive in-service inspections of primary components in nuclear power plants. It features two main advantages: the short examination duration and the fast interpretation of results. AREVA offers operators of nuclear power plants the ''SUSI 420 HD'' SUbmarine System for Inspections to perform ENIQ-qualified visual examinations during outages without working on the critical path and causing any delay in the time schedule. The system is a remotely operated manipulator equipped with a high definition camera. With a weight of only 25 kg, there is no need for a crane to put the submarine into water. More-over, nor the use of the refueling machine neither the auxiliary bridge is required. In this way the visual examination can be performed in parallel to other activities which are on the critical path. The article takes a closer look at the essential parameters: illumination, examination distance, viewing angle, scanning speed, positioning accuracy and sizing of indications. It describes how the system can fulfill these parameters through some adaptations.

  18. WHAT CONTROLS STEM CELL DEVELOPMENT-- CELL POTENTIAL OR LOCAL ENVIRONMENT?

    Science.gov (United States)

    In H. virescens, as in M. sexta and other lepidoptera, midgut development proceeds through the sequential proliferation and differentiation of the midgut stem cells. In larvae,the stem cells repeatedly differentiatiate to goblet, columnar, and to a lesser extent endocrine cells of the midgut; a res...

  19. Stromal control of chronic lymphocytic leukemia cells

    Directory of Open Access Journals (Sweden)

    Seke Etet PF

    2013-09-01

    Full Text Available Paul Faustin Seke Etet,1 Armel Herve Nwabo Kamdje,2 Jeremie Mbo Amvene,2 Yousef Aldebasi,3 Mohammed Farahna,1 Lorella Vecchio41Department of Basic Health Sciences, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia; 2Department of Medicine, University of Ngaoundere, Ngaoundere, Cameroon; 3Department of Optometry, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia; 4Laboratory of Cytometry, Institute of Molecular Genetics, CNR, University of Pavia, Pavia, ItalyAbstract: In the ongoing efforts to develop therapies against chronic lymphocytic leukemia (CLL, stromal factors allowing malignant cells to escape spontaneous and chemotherapy-mediated apoptosis, giving way to relapses, have been abundantly investigated. Bone marrow adherent cell types, collectively referred to as stromal cells, appear to be key players in such escape, mainly because CLL malignant cells, which rapidly undergo spontaneous apoptosis when cultured in vitro, survive, migrate, and resist cytotoxic agents in co-culture with bone marrow stromal cells. CLL displays variable clinical courses according to well-defined prognostic factors induced on malignant B-cells (CLL cells or expressed by the transformed bone marrow stromal microenvironment. Particularly, a critical pathogenic role is played by proinflammatory factors, adhesion molecules, and signaling molecules involved in cell fate and stemness, such as Notch, Wnt, sonic Hedgehog, phosphoinositide 3-kinase (PI3K, protein kinase B (Akt, and the B-cell CLL/lymphoma 2 (Bcl-2 family of regulator proteins. As herein discussed, these molecules probably form a complex network favoring CLL cell survival, proliferation, and chemoresistance to anticancer therapy. Characterizing the sets of signaling pathways involved in the interactions between stromal cells and CLL cells may provide new tools for CLL clinical phenotyping and for re-sensitizing chemotherapy resistant cells

  20. The effects of virtual reality displays on visual attention and detection of signals performance for main control room training

    International Nuclear Information System (INIS)

    The nuclear power plant (NPP) mainly serve the purpose to provide low-cost and stable electricity for the people, but this purpose must be dependent upon the premise of 'safety first.' The reason for this is that the occurrence of nuclear power plant accidents could cause catastrophic damage to the people, property, society, and the environment. Therefore, training in superior and high reliability system is very important in accident prevention. In recent years, the Virtual Reality (VR) technology advances very fast as well as the technology for e-learning environment. VR systems have been applied for education, safety training of NPP and flying simulators. In particular, VR is an interactive and reactive technology; it allows users to interact and navigate with objects in the virtual environment. Development of VR and simulation techniques contributes to an accurate and immersive training environment for NPP operators. Main Control Room (MCR) training simulator based on VR is a more cost effective and efficient alternative to traditional simulator based training methods. The VR simulation for MCR training is a complex task. Since VR not only reinforces the visual presentation of the training materials but also provides ways to interact with the training system, it becomes more flexible and possibly more powerful in the training system. In the VR training system, the MCR operators may use just one display to view the wide range of the real world displays. The field of view (FOV) will be different from the real MCR environment in which many displays exist for the operators to view. Thus operator's immersion and visual attention will be reduced. This is the problem of MCR virtual training compared with the traditional simulator based training systems. Therefore, improving the operator's visual attention and the detection of signals in VR training system is a very important issue. This investigation intends to contribute in assessing benefits of visual attention and

  1. Simulator of the punctual kinetics of a TRIGA Mark III reactor with power diffuse control in a visual environment; Simulador de la cinetica puntual de un reactor nuclear TRIGA Mark III con control difuso de potencia en un ambiente visual

    Energy Technology Data Exchange (ETDEWEB)

    Perez M, C

    2004-07-01

    The development of a software is presented that simulates the punctual kinetics of a nuclear reactor of investigation model TRIGA Mark III, generating the answers of the reactor low different algorithms of control of power. The user requires a graphic interface that allows him easily interacting with the simulator. To achieve the proposed objective, first the system was modeled in open loop, not using a mathematical model of the consistent reactor in a system of linear ordinary differential equations. For their solution in real time the numeric method of Runge-Kutta-Fehlberg was used. As second phase, it was modeled to the system in closed loop, using for it an algorithm of control of the power based on fuzzy logic. This software has as purpose to help the investigator in the control area who will be able to prove different algorithms for the control of the power of the reactor. This is achieved using the code source in language C, C++, Visual Basic, with which a file is generated. DLL and it is inserted in the simulator. Then they will be able to visualize the results as if their controller had installed in the reactor, analyzing the behavior of all his variables that will be stored in files, for his later study. The easiness of proving these control algorithms in the reactor without necessity to make it physically has important consequences as the saving in the expense of fuel, the not generation of radioactive waste and the most important thing, one doesn't run any risk. The simulator can be used how many times it is necessary until the total purification of the algorithm. This program is the base for following investigation processes, enlarging the capacities and options of the same one. The program fulfills the time of execution satisfactorily, assisting to the necessity of visualizing the behavior in real time of the reactor, and it responds from an effective way to the petitions of changes of power on the part of the user. (Author)

  2. Laser Ultrasonic System for Surface Crack Visualization in Dissimilar Welds of Control Rod Drive Mechanism Assembly of Nuclear Power Plant

    Directory of Open Access Journals (Sweden)

    Yun-Shil Choi

    2014-01-01

    Full Text Available In this paper, we propose a J-groove dissimilar weld crack visualization system based on ultrasonic propagation imaging (UPI technology. A full-scale control rod drive mechanism (CRDM assembly specimen was fabricated to verify the proposed system. An ultrasonic sensor was contacted at one point of the inner surface of the reactor vessel head part of the CRDM assembly. Q-switched laser beams were scanned to generate ultrasonic waves around the weld bead. The localization and sizing of the crack were possible by ultrasonic wave propagation imaging. Furthermore, ultrasonic spectral imaging unveiled frequency components of damage-induced waves, while wavelet-transformed ultrasonic propagation imaging enhanced damage visibility by generating a wave propagation video focused on the frequency component of the damage-induced waves. Dual-directional anomalous wave propagation imaging with adjacent wave subtraction was also developed to enhance the crack visibility regardless of crack orientation and wave propagation direction. In conclusion, the full-scale specimen test demonstrated that the multiple damage visualization tools are very effective in the visualization of J-groove dissimilar weld cracks.

  3. Moving-base visual simulation study of decoupled controls during approach and landing of a STOL transport aircraft

    Science.gov (United States)

    Miller, G. K., Jr.; Deal, P. L.

    1975-01-01

    The simulation employed all six rigid-body degrees of freedom and incorporated aerodynamic characteristics based on wind-tunnel data. The flight instrumentation included a localizer and a flight director which was used to capture and to maintain a two-segment glide slope. A closed-circuit television display of a STOLport provided visual cues during simulations of the approach and landing. The decoupled longitudinal controls used constant prefilter and feedback gains to provide steady-state decoupling of flight-path angle, pitch angle, and forward velocity. The pilots were enthusiastic about the decoupled longitudinal controls and believed that the simulator motion was an aid in evaluating the decoupled controls, although a minimum turbulence level with root-mean-square gust intensity of 0.3 m/sec (1 ft/sec) was required to mask undesirable characteristics of the moving-base simulator.

  4. Visual guidance of forward flight in hummingbirds reveals control based on image features instead of pattern velocity.

    Science.gov (United States)

    Dakin, Roslyn; Fellows, Tyee K; Altshuler, Douglas L

    2016-08-01

    Information about self-motion and obstacles in the environment is encoded by optic flow, the movement of images on the eye. Decades of research have revealed that flying insects control speed, altitude, and trajectory by a simple strategy of maintaining or balancing the translational velocity of images on the eyes, known as pattern velocity. It has been proposed that birds may use a similar algorithm but this hypothesis has not been tested directly. We examined the influence of pattern velocity on avian flight by manipulating the motion of patterns on the walls of a tunnel traversed by Anna's hummingbirds. Contrary to prediction, we found that lateral course control is not based on regulating nasal-to-temporal pattern velocity. Instead, birds closely monitored feature height in the vertical axis, and steered away from taller features even in the absence of nasal-to-temporal pattern velocity cues. For vertical course control, we observed that birds adjusted their flight altitude in response to upward motion of the horizontal plane, which simulates vertical descent. Collectively, our results suggest that birds avoid collisions using visual cues in the vertical axis. Specifically, we propose that birds monitor the vertical extent of features in the lateral visual field to assess distances to the side, and vertical pattern velocity to avoid collisions with the ground. These distinct strategies may derive from greater need to avoid collisions in birds, compared with small insects. PMID:27432982

  5. Controlled Delivery of Human Cells by Temperature Responsive Microcapsules

    Directory of Open Access Journals (Sweden)

    W.C. Mak

    2015-06-01

    Full Text Available Cell therapy is one of the most promising areas within regenerative medicine. However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into. Encapsulation of individual cells has been proposed as a means of increasing cell viability. In this study, we developed a facile, high throughput method for creating temperature responsive microcapsules comprising agarose, gelatin and fibrinogen for delivery and subsequent controlled release of cells. We verified the hypothesis that composite capsules combining agarose and gelatin, which possess different phase transition temperatures from solid to liquid, facilitated the destabilization of the capsules for cell release. Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line—human umbilical vein endothelial cells (HUVECs. While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.

  6. Mitochondrial Dynamics Controls T Cell Fate through Metabolic Programming.

    Science.gov (United States)

    Buck, Michael D; O'Sullivan, David; Klein Geltink, Ramon I; Curtis, Jonathan D; Chang, Chih-Hao; Sanin, David E; Qiu, Jing; Kretz, Oliver; Braas, Daniel; van der Windt, Gerritje J W; Chen, Qiongyu; Huang, Stanley Ching-Cheng; O'Neill, Christina M; Edelson, Brian T; Pearce, Edward J; Sesaki, Hiromi; Huber, Tobias B; Rambold, Angelika S; Pearce, Erika L

    2016-06-30

    Activated effector T (TE) cells augment anabolic pathways of metabolism, such as aerobic glycolysis, while memory T (TM) cells engage catabolic pathways, like fatty acid oxidation (FAO). However, signals that drive these differences remain unclear. Mitochondria are metabolic organelles that actively transform their ultrastructure. Therefore, we questioned whether mitochondrial dynamics controlscell metabolism. We show that TE cells have punctate mitochondria, while TM cells maintain fused networks. The fusion protein Opa1 is required for TM, but not TE cells after infection, and enforcing fusion in TE cells imposes TM cell characteristics and enhances antitumor function. Our data suggest that, by altering cristae morphology, fusion in TM cells configures electron transport chain (ETC) complex associations favoring oxidative phosphorylation (OXPHOS) and FAO, while fission in TE cells leads to cristae expansion, reducing ETC efficiency and promoting aerobic glycolysis. Thus, mitochondrial remodeling is a signaling mechanism that instructs T cell metabolic programming. PMID:27293185

  7. Severe visual Impairment and blindness in infants: Causes and opportunities for control

    Directory of Open Access Journals (Sweden)

    Parikshit Gogate

    2011-01-01

    Full Text Available Childhood blindness has an adverse effect on growth, development, social, and economic opportunities. Severe visual impairment (SVI and blindness in infants must be detected as early as possible to initiate immediate treatment to prevent deep amblyopia. Although difficult, measurement of visual acuity of an infant is possible. The causes of SVI and blindness may be prenatal, perinatal, and postnatal. Congenital anomalies such as anophthalmos, microphthalmos, coloboma, congenital cataract, infantile glaucoma, and neuro-ophthalmic lesions are causes of impairment present at birth. Ophthalmia neonatorum, retinopathy of prematurity, and cortical visual impairment are acquired during the perinatal period. Leukocoria or white pupillary reflex can be cause by congenital cataract, persistent hyperplastic primary vitreous, or retinoblastoma. While few medical or surgical options are available for congenital anomalies or neuro-ophthalmic disorders, many affected infants can still benefit from low vision aids and rehabilitation. Ideally, surgery for congenital cataracts should occur within the first 4 months of life. Anterior vitrectomy and primary posterior capsulotomy are required, followed by aphakic glasses with secondary intraocular lens implantation at a later date. The treatment of infantile glaucoma is surgery followed by anti-glaucoma medication. Retinopathy of prematurity is a proliferation of the retinal vasculature in response to relative hypoxia in a premature infant. Screening in the first few weeks of life can prevent blindness. Retinoblastoma can be debulked with chemotherapy; however, enucleation may still be required. Neonatologists, pediatricians, traditional birth attendants, nurses, and ophthalmologists should be sensitive to a parent′s complaints of poor vision in an infant and ensure adequate follow-up to determine the cause. If required, evaluation under anesthesia should be performed, which includes funduscopy, refraction

  8. Visiting Richard Serra’s Promenade sculpture improves postural control and judgment of subjective visual vertical.

    Directory of Open Access Journals (Sweden)

    Zoï eKapoula

    2014-12-01

    Full Text Available Body sway while maintaining an upright quiet stance reflects an active process of balance based on the integration of visual, vestibular, somatosensory and proprioceptive inputs. Richard Serra’s Promenade sculpture featured in the 2008 Monumenta exhibition at the Grand Palais in Paris, France is herein hypothesised to have stimulated the body’s vertical and longitudinal axes as it showcased 5 monumental rectangular solids pitched at a 1.69° angle.Using computerised dynamic posturography we measured the body sway of 23 visitors when fixating a cross, or when observing the artwork (fixating it or actively exploring it with eye movements before and after walking around and alongside the sculpture (i.e., before and after a promenade. A first fixation at the sculpture increased medio-lateral stability (in terms of spectral power of body sway. Eye movement exploration in the depth of the sculpture increased antero-posterior stability (in terms of spectral power and cancelling time of body sway at the expense of medio-lateral stability (in terms of cancelling time. Moreover, a medio-lateral instability associated with eye movement exploration before the promenade (in terms of body sway sensu stricto was cancelled after the promenade. Finally, the overall medio-lateral stability (in terms of spectral power increased after the promenade.Fourteen additional visitors were asked to sit in a dark room and adjust a luminous line to what they considered to be the earth-vertical axis. The promenade executed within the sculpted environment afforded by Serra’s monumental statuary works resulted in significantly improved performances on the subjective visual vertical test.We attribute these effects to the sculpted environment provided by the exhibition which may have acted as a kind of physiologic training ground thereby improving the visitors’ overall sense of visual perspective, equilibrium and gravity.

  9. Visualization of electrical field of electrode using voltage-controlled fluorescence release.

    Science.gov (United States)

    Jia, Wenyan; Wu, Jiamin; Gao, Di; Wang, Hao; Sun, Mingui

    2016-08-01

    In this study we propose an approach to directly visualize electrical current distribution at the electrode-electrolyte interface of a biopotential electrode. High-speed fluorescent microscopic images are acquired when an electric potential is applied across the interface to trigger the release of fluorescent material from the surface of the electrode. These images are analyzed computationally to obtain the distribution of the electric field from the fluorescent intensity of each pixel. Our approach allows direct observation of microscopic electrical current distribution around the electrode. Experiments are conducted to validate the feasibility of the fluorescent imaging method. PMID:27253615

  10. Visually altering user controls in ASP.NET with Photoshop and CSS

    OpenAIRE

    Cojoc, Marius

    2013-01-01

    The need for this thesis project arose after the completion of several courses on building ASP.NET webpages and applications: there seemed to be a lack of information regarding the ways how to style webpages and to give them a different look from the default. During the courses the focus was mainly on programming aspects, be them frontend, backend or XHTML, but little was mentioned about the possibilities to modify the content visually. The purpose of this thesis project was to present a...

  11. Visualization tool for X-ray scanner for sTGC detector production quality control

    Science.gov (United States)

    Tikhomirov, V. O.; Filippov, K. A.; Konovalov, S. P.; Mikenberg, G.; Romaniouk, A.; Shchukin, D.; Shoa, M.; Smakhtin, V.; Smirnov, S. Yu; Sosnovtsev, V. V.; Teterin, P. E.; Tsekhosh, V. I.; Vorobev, K. A.

    2016-02-01

    The ATLAS experiment at the Large Hadron Collider has an ambitious program of the detector upgrade to meet an expected rise of accelerator luminosity. The first large system which supposed to be installed in 2019 is the New Small Wheel (NSW) for ATLAS muon spectrometer. In order to ensure high quality and reliability of NSW chambers an X-ray scanning technique is being developed. One of the main components of the X-ray scanner is a special software visualization tool which would allow a fast and clear representation of scanning results and an identification of possible chamber defects.

  12. Visualization of Flow Separation and Control by Vortex Generators on an Single Flap in Landing Configuration

    Czech Academy of Sciences Publication Activity Database

    Součková, Natálie; Kuklová, J.; Popelka, Lukáš; Matějka, Milan

    Liberec: Technical University of Liberec, 2010 - (Vít, T.; Dančová, P.), s. 1-12 ISBN 978-80-7372-670-6. [Experimental Fluid Mechanics 2010. Liberec (CZ), 24.11.2010-26.11.2010] R&D Projects: GA MŠk(CZ) 1M06031; GA ČR GAP101/10/1230; GA ČR GA101/08/1112; GA ČR GA103/09/0977 Institutional research plan: CEZ:AV0Z20760514 Keywords : flow separation * vortex generators * visualization Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts

  13. Visualization of the solubilization process of the plasma membrane of a living cell by waveguide evanescent field fluorescence microscopy

    Science.gov (United States)

    Hassanzadeh, Abdollah; Ma, Heun Kan; Dixon, S. Jeffrey; Mittler, Silvia

    2012-07-01

    Waveguide evanescent field fluorescence microscopy (WEFF) is a novel microscopy technology that allows imaging of a cell's plasma membrane in the vicinity of a glass substrate with high axial resolution, low background and little photobleaching. Time-lapse imaging can be performed to investigate changes in cell morphology in the presence or absence of chemical agents. WEFF microscopy provides a method to investigate plasma membranes of living cells and allows a comparison to simplified model membranes immobilized on planar substrates. The interaction of the nonionic detergent Triton X-100 with plasma membranes of osteoblasts in an aqueous environment was investigated. Solubilization of the membranes very close to the waveguide surface was visualized and related to the three-stage solubilisation model proposed for liposomes and supported lipid bilayers. Findings for the plasma membranes of cells are in excellent agreement with results reported for these artificial model systems.

  14. Human Embryonic and Hepatic Stem Cell Differentiation Visualized in Two and Three Dimensions Based on Serial Sections

    DEFF Research Database (Denmark)

    Vestentoft, Peter S.; Brøchner, Christian B; Lynnerup, Niels;

    2016-01-01

    Pluripotent human embryonic stem cells (hESCs) are characterized by two defining properties, self-renewal and differentiation. Self-renewing hESCs express transcription factors OCT4, SOX2, and NANOG, and surface markers SSEA-4 and TRA-1-60 and TRA-1-81 and their ability to differentiate into...... an entire colony is accomplished using 3D image processing software such as Mimics(®) or Amira(®). An extended version of this technique even allows for a high-magnification 3D-reconstruction of, e.g., hepatic stem cells in developing liver. These techniques combined allow for both a 2- and a 3......-dimensional visualization of hESC colonies and stem cells in organs, which leads to new insights into and information about the interaction of stem cells with their surroundings....

  15. Energy, control and DNA structure in the living cell

    DEFF Research Database (Denmark)

    Wijker, J.E.; Jensen, Peter Ruhdal; Gomes, A. Vaz;

    1995-01-01

    directly or via “storage” in an intermediate high energy form, i.e., highATPADP ratio or H+ ion gradient. Although maintenance of a sufficiently high ATPADP ratio is essential to overcome the thermodynamic burden of uphill processes, it is not clear to what degree enzymes that control this ratio also...... control cell physiology. Indeed, in the living cell homeostatic control mechanisms might exist for the free-energy transduction pathways so as to prevent perturbation of cellular function when the Gibbs energy supply is compromised. This presentation addresses the extent to which the intracellular ATP...... level is involved in the control of cell physiology, how the elaborate control of cell function may be analyzed theoretically and quantitatively, and if this can be utilized selectively to affect certain cell types....

  16. Controling stem cell proliferation - CKIs at work

    NARCIS (Netherlands)

    Bruggeman, SWM; van Lohuizen, M

    2006-01-01

    The cyclin-dependent kinase inhibitors or CKIs are well recognized as intrinsic regulators of the cell cycle. Here, we discuss recent data implicating their activity in restraining adult stem cell self-renewal, and the role that proteins regulating CKI expression play in this process.

  17. Control of cell proliferation by Myc

    DEFF Research Database (Denmark)

    Bouchard, C; Staller, P; Eilers, M

    1998-01-01

    Myc proteins are key regulators of mammalian cell proliferation. They are transcription factors that activate genes as part of a heterodimeric complex with the protein Max. This review summarizes recent progress in understanding how Myc stimulates cell proliferation and how this might contribute to...

  18. Study on the Architecture of Control System for Manufacturing Cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The depiction of the agile manufacturing cell includes a synopsis of some of the change proficiencies obtained by the configuration. To achieve agile configuration, the cell control system for agile manufacturing must be rapidly and efficiently generated or modified. In this paper, the object-oriented architecture is defined that supports design and implementation of highly reconfigurable control systems for agile manufacturing cells, which is composed of database objects, control objects, and resource objects, so as to reduce costs and to increase the control system's agility with respect to changing environment.

  19. Organic Based Solar Cells with Morphology Control

    DEFF Research Database (Denmark)

    Andersen, Thomas Rieks

    Microscopy and as solar cells in a blend with PCBM. It was concluded that these particles did not show a potential large enough for continuous work due to a high material loss and low efficiency when applied in solar cells. The second method to achieve was preparation of pre-arranged morphology organic......The field of organic solar cells has in the last years gone through an impressive development with efficiencies reported up to 12 %. For organic solar cells to take the leap from primarily being a laboratory scale technology to being utilized as renewable energy source, several issues need to be...... nanoparticles consisting of a blend of donor and acceptor in an aqueous dispersion, thereby addressing two of the issues remaining in the field of organic solar cells. This approach was used on six different polymers, which all had the ability to prepare aqueous nanoparticle inks. The morphology of the...

  20. Transcriptional control of stem cell maintenance in the Drosophila intestine

    OpenAIRE

    Bardin, Allison J.; Perdigoto, Carolina N.; Southall, Tony D.; Brand, Andrea H; Schweisguth, François

    2010-01-01

    Adult stem cells maintain tissue homeostasis by controlling the proper balance of stem cell self-renewal and differentiation. The adult midgut of Drosophila contains multipotent intestinal stem cells (ISCs) that self-renew and produce differentiated progeny. Control of ISC identity and maintenance is poorly understood. Here we find that transcriptional repression of Notch target genes by a Hairless-Suppressor of Hairless complex is required for ISC maintenance, and identify genes of the Enhan...

  1. A parallel control architecture for industrial robot cells

    OpenAIRE

    Henrich, Dominik; Abegg, Frank; Wurll, Christian; Wörn, Heinz

    1998-01-01

    We present a parallel control architecture for industrial robot cells. It is based on closed functional components arranged in a flat communication hierarchy. The components may be executed by different processing elements, and each component itself may run on multiple processing elements. The system is driven by the instructions of a central cell control component. We set up necessary requirements for industrial robot cells and possible parallelization levels. These are met by the suggested ...

  2. 3D visualization based customer experiences of nuclear plant control room

    International Nuclear Information System (INIS)

    This paper employs virtual reality (VR) technology to develop an interactive virtual nuclear plant control room in which the general public could easily walk into the 'red zone' and play with the control buttons. The VR-based approach allows deeper and richer customer experiences that the real nuclear plant control room could not offer. When people know more about the serious process control procedures enforced in the nuclear plant control room, they will appropriate more about the safety efforts imposed by the nuclear plant and become more comfortable about the nuclear plant. The virtual nuclear plant control room is built using a 3D game development tool called Unity3D. The 3D scene is connected to a nuclear plant simulation system through Windows API programs. To evaluate the usability of the virtual control room, an experiment will be conducted to see how much 'immersion' the users could feel when they played with the virtual control room. (author)

  3. Simulator of the punctual kinetics of a TRIGA Mark III reactor with power diffuse control in a visual environment

    International Nuclear Information System (INIS)

    The development of a software is presented that simulates the punctual kinetics of a nuclear reactor of investigation model TRIGA Mark III, generating the answers of the reactor low different algorithms of control of power. The user requires a graphic interface that allows him easily interacting with the simulator. To achieve the proposed objective, first the system was modeled in open loop, not using a mathematical model of the consistent reactor in a system of linear ordinary differential equations. For their solution in real time the numeric method of Runge-Kutta-Fehlberg was used. As second phase, it was modeled to the system in closed loop, using for it an algorithm of control of the power based on fuzzy logic. This software has as purpose to help the investigator in the control area who will be able to prove different algorithms for the control of the power of the reactor. This is achieved using the code source in language C, C++, Visual Basic, with which a file is generated. DLL and it is inserted in the simulator. Then they will be able to visualize the results as if their controller had installed in the reactor, analyzing the behavior of all his variables that will be stored in files, for his later study. The easiness of proving these control algorithms in the reactor without necessity to make it physically has important consequences as the saving in the expense of fuel, the not generation of radioactive waste and the most important thing, one doesn't run any risk. The simulator can be used how many times it is necessary until the total purification of the algorithm. This program is the base for following investigation processes, enlarging the capacities and options of the same one. The program fulfills the time of execution satisfactorily, assisting to the necessity of visualizing the behavior in real time of the reactor, and it responds from an effective way to the petitions of changes of power on the part of the user. (Author)

  4. Assessment of Visual Reliance in Balance Control: An Inexpensive Extension of the Static Posturography

    Directory of Open Access Journals (Sweden)

    Jozef Púčik

    2014-01-01

    Full Text Available Ability of humans to maintain balance in an upright stance and during movement activities is one of the most natural skills affecting everyday life. This ability progressively deteriorates with increasing age, and balance impairment, often aggravated by age-related diseases, can result in falls that adversely impact the quality of life. Falls represent serious problems of health concern associated with aging. Many investigators, involved in different science disciplines such as medicine, engineering, psychology, and sport, have been attracted by a research of the human upright stance. In a clinical practice, stabilometry based on the force plate is the most widely available procedure used to evaluate the balance. In this paper, we have proposed a low-cost extension of the conventional stabilometry by the multimedia technology that allows identifying potentially disturbing effects of visual sensory information. Due to the proposed extension, a stabilometric assessment in terms of line integral of center of pressure (COP during moving scene stimuli shows higher discrimination power between young healthy and elderly subjects with supposed stronger visual reliance.

  5. Static and Motion-Based Visual Features Used by Airport Tower Controllers: Some Implications for the Design of Remote or Virtual Towers

    Science.gov (United States)

    Ellis, Stephen R.; Liston, Dorion B.

    2011-01-01

    Visual motion and other visual cues are used by tower controllers to provide important support for their control tasks at and near airports. These cues are particularly important for anticipated separation. Some of them, which we call visual features, have been identified from structured interviews and discussions with 24 active air traffic controllers or supervisors. The visual information that these features provide has been analyzed with respect to possible ways it could be presented at a remote tower that does not allow a direct view of the airport. Two types of remote towers are possible. One could be based on a plan-view, map-like computer-generated display of the airport and its immediate surroundings. An alternative would present a composite perspective view of the airport and its surroundings, possibly provided by an array of radially mounted cameras positioned at the airport in lieu of a tower. An initial more detailed analyses of one of the specific landing cues identified by the controllers, landing deceleration, is provided as a basis for evaluating how controllers might detect and use it. Understanding other such cues will help identify the information that may be degraded or lost in a remote or virtual tower not located at the airport. Some initial suggestions how some of the lost visual information may be presented in displays are mentioned. Many of the cues considered involve visual motion, though some important static cues are also discussed.

  6. Super-resolution imaging with Pontamine Fast Scarlet 4BS enables direct visualization of cellulose orientation and cell connection architecture in onion epidermis cells

    DEFF Research Database (Denmark)

    Liesche, Johannes; Ziomkiewicz, Iwona; Schulz, Alexander

    2013-01-01

    microscopy of some 200 nm in xy and 550 nm in z for green light, restricts the direct visualization of cellulose to relatively large bundles, whereas the structure of cellulose microfibrils with their diameter below 10 nm remains unresolved. Over the last decade, several so-called super-resolution microscopy...... approaches have been developed; in this paper we explore the potential of such approaches for the direct visualization of cellulose. Results To ensure optimal imaging we determined the spectral properties of PFS-stained tissue. PFS was found not to affect cell viability in the onion bulb scale epidermis. We...... confocal microscopy and the approach could be used to demonstrate differences in fibril orientation in different layers of the cell wall as well as particular cellulose fortifications around plasmodesmata. Conclusions Super-resolution light microscopy of PFS-stained cellulose fibrils is possible...

  7. Muscle Stem Cell Fate Is Controlled by the Cell-Polarity Protein Scrib

    Directory of Open Access Journals (Sweden)

    Yusuke Ono

    2015-02-01

    Full Text Available Satellite cells are resident skeletal muscle stem cells that supply myonuclei for homeostasis, hypertrophy, and repair in adult muscle. Scrib is one of the major cell-polarity proteins, acting as a potent tumor suppressor in epithelial cells. Here, we show that Scrib also controls satellite-cell-fate decisions in adult mice. Scrib is undetectable in quiescent cells but becomes expressed during activation. Scrib is asymmetrically distributed in dividing daughter cells, with robust accumulation in cells committed to myogenic differentiation. Low Scrib expression is associated with the proliferative state and preventing self-renewal, whereas high Scrib levels reduce satellite cell proliferation. Satellite-cell-specific knockout of Scrib in mice causes a drastic and insurmountable defect in muscle regeneration. Thus, Scrib is a regulator of tissue stem cells, controlling population expansion and self-renewal with Scrib expression dynamics directing satellite cell fate.

  8. The Design and Development of a User-Controlled Visual Aid for Improving Students' Understanding in Introductory Statistics

    Science.gov (United States)

    Vaughn, Brandon K.; Wang, Pei-Yu

    2009-01-01

    The use of visual aids is expected to have a positive effect on students' learning. However, not all visual aids work equally well. A recent meta-analytic research which examined 42 studies has found that the use of animated visuals does not facilitate learning (Anglin, Vaez & Cunnincham, 2004). The failure of visual aids can be attributed to…

  9. Necdin Controls Proliferation of White Adipocyte Progenitor Cells

    OpenAIRE

    Fujiwara, Kazushiro; Hasegawa, Koichi; Ohkumo, Tsuyoshi; Miyoshi, Hiroyuki; Yoshikawa, Kazuaki; Tseng, Yu-Hua

    2012-01-01

    White adipose tissues are composed mainly of white fat cells (adipocytes), which play a key role in energy storage and metabolism. White adipocytes are terminally differentiated postmitotic cells and arise from their progenitor cells (preadipocytes) or mesenchymal stem cells residing in white adipose tissues. Thus, white adipocyte number is most likely controlled by the rate of preadipocyte proliferation, which may contribute to the etiology of obesity. However, little is known about the mole...

  10. Design and implementation of visual-haptic assistive control system for virtual rehabilitation exercise and teleoperation manipulation.

    Science.gov (United States)

    Veras, Eduardo J; De Laurentis, Kathryn J; Dubey, Rajiv

    2008-01-01

    This paper describes the design and implementation of a control system that integrates visual and haptic information to give assistive force feedback through a haptic controller (Omni Phantom) to the user. A sensor-based assistive function and velocity scaling program provides force feedback that helps the user complete trajectory following exercises for rehabilitation purposes. This system also incorporates a PUMA robot for teleoperation, which implements a camera and a laser range finder, controlled in real time by a PC, were implemented into the system to help the user to define the intended path to the selected target. The real-time force feedback from the remote robot to the haptic controller is made possible by using effective multithreading programming strategies in the control system design and by novel sensor integration. The sensor-based assistant function concept applied to teleoperation as well as shared control enhances the motion range and manipulation capabilities of the users executing rehabilitation exercises such as trajectory following along a sensor-based defined path. The system is modularly designed to allow for integration of different master devices and sensors. Furthermore, because this real-time system is versatile the haptic component can be used separately from the telerobotic component; in other words, one can use the haptic device for rehabilitation purposes for cases in which assistance is needed to perform tasks (e.g., stroke rehab) and also for teleoperation with force feedback and sensor assistance in either supervisory or automatic modes. PMID:19163661

  11. Cell size checkpoint control by the retinoblastoma tumor suppressor pathway.

    Directory of Open Access Journals (Sweden)

    Su-Chiung Fang

    2006-10-01

    Full Text Available Size control is essential for all proliferating cells, and is thought to be regulated by checkpoints that couple cell size to cell cycle progression. The aberrant cell-size phenotypes caused by mutations in the retinoblastoma (RB tumor suppressor pathway are consistent with a role in size checkpoint control, but indirect effects on size caused by altered cell cycle kinetics are difficult to rule out. The multiple fission cell cycle of the unicellular alga Chlamydomonas reinhardtii uncouples growth from division, allowing direct assessment of the relationship between size phenotypes and checkpoint function. Mutations in the C. reinhardtii RB homolog encoded by MAT3 cause supernumerous cell divisions and small cells, suggesting a role for MAT3 in size control. We identified suppressors of an mat3 null allele that had recessive mutations in DP1 or dominant mutations in E2F1, loci encoding homologs of a heterodimeric transcription factor that is targeted by RB-related proteins. Significantly, we determined that the dp1 and e2f1 phenotypes were caused by defects in size checkpoint control and were not due to a lengthened cell cycle. Despite their cell division defects, mat3, dp1, and e2f1 mutants showed almost no changes in periodic transcription of genes induced during S phase and mitosis, many of which are conserved targets of the RB pathway. Conversely, we found that regulation of cell size was unaffected when S phase and mitotic transcription were inhibited. Our data provide direct evidence that the RB pathway mediates cell size checkpoint control and suggest that such control is not directly coupled to the magnitude of periodic cell cycle transcription.

  12. Effects of the concomitant activation of ON and OFF retinal ganglion cells on the visual thalamus: evidence for an enhanced recruitment of GABAergic cells

    Directory of Open Access Journals (Sweden)

    Giovanni Montesano

    2015-11-01

    Full Text Available A fundamental question in vision neuroscience is how parallel processing of Retinal Ganglion Cell (RGC signals is integrated at the level of the visual thalamus. It is well known that parallel ON-OFF pathways generate output signals from the retina that are conveyed to the dorsal lateral geniculate nucleus (dLGN. However, it is unclear how these signals distribute onto thalamic cells and how these two pathways interact. Here, by electrophysiological recordings and c-Fos expression analysis, we characterized the effects of pharmacological manipulations of the retinal circuit aimed at inducing either a selective activation of a single pathway, OFF RGCs (intravitreal L-(+-2-Amino-4-phosphonobutyric, L-AP4 or an unregulated activity of all classes of retinal ganglion cells (intravitreal 4-Aminopyridine, 4-AP. In in vivo experiments, the analysis of c-Fos expression in the dLGN showed that these two manipulations recruited active cells from the same area, the lateral edge of the dLGN. Despite this similarity, the unregulated co-activation of both ON and OFF pathways by 4-AP yielded a much stronger recruitment of GABAergic interneurons in the dLGN when compared to L-AP4 pure OFF activation. The increased activation of an inhibitory thalamic network by a high level of unregulated discharge of ON and OFF RGCs might suggest that cross-inhibitory pathways between opposing visual channels are presumably replicated at multiple levels in the visual pathway, thus increasing the filtering ability for non-informative or noisy visual signals.

  13. Visual input controls the functional activity of goldfish Mauthner neuron through the reciprocal synaptic mechanism.

    Science.gov (United States)

    Moshkov, Dmitry A; Shtanchaev, Rashid S; Mikheeva, Irina B; Bezgina, Elena N; Kokanova, Nadezhda A; Mikhailova, Gulnara Z; Tiras, Nadezhda R; Pavlik, Lyubov' L

    2013-03-01

    Goldfish are known to exhibit motor asymmetry due to functional asymmetry of their Mauthner neurons that induce the turns to the right or left during free swimming. It has been previously found that if the less active neuron is subjected to prolonged aimed visual stimulation via its ventral dendrite, the motor asymmetry of goldfish is inverted, testifying that this neuron becomes functionally dominant, while the size of the ventral dendrite under these conditions is reduced 2-3 times compared to its counterpart in mirror neuron. Earlier it has been also revealed that training optokinetic stimulation induces adaptation, a substantial resistance of both fish motor asymmetry and morphofunctional state of Mauthner neurons against prolonged optokinetic stimulation. The aim of this work was to study the cellular mechanisms of the effect of an unusual visual afferent input on goldfish motor asymmetry and Mauthner neuron function in norm and under adaptation. It was shown that serotonin applied onto Mauthner neurons greatly reduces their activity whereas its antagonist ondansetron increases it. Against the background of visual stimulation, serotonin strengthens functional asymmetry between neurons whereas ondansetron smoothes it. Taken together these data suggest the involvement of serotonergic excitatory synaptic transmission in the regulation of Mauthner neurons by vision. Ultrastructural study of the ventral dendrites after prolonged optokinetic stimulation has revealed depletions of numeral axo-axonal synapses with specific morphology, identified by means of immunogold label as serotonergic ones. These latter in turn are situated mainly on shaft boutons, which according to specific ultrastructural features are assigned to axo-dendritic inhibitory synapses. Thus, the excitatory serotonergic synapses seem to affect Mauthner neuron indirectly through inhibitory synapses. Further, it was morphometrically established that adaptation is accompanied by the significant

  14. Optimized labeling of bone marrow mesenchymal cells with superparamagnetic iron oxide nanoparticles and in vivo visualization by magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Spray David C

    2011-02-01

    Full Text Available Abstract Background Stem cell therapy has emerged as a promising addition to traditional treatments for a number of diseases. However, harnessing the therapeutic potential of stem cells requires an understanding of their fate in vivo. Non-invasive cell tracking can provide knowledge about mechanisms responsible for functional improvement of host tissue. Superparamagnetic iron oxide nanoparticles (SPIONs have been used to label and visualize various cell types with magnetic resonance imaging (MRI. In this study we performed experiments designed to investigate the biological properties, including proliferation, viability and differentiation capacity of mesenchymal cells (MSCs labeled with clinically approved SPIONs. Results Rat and mouse MSCs were isolated, cultured, and incubated with dextran-covered SPIONs (ferumoxide alone or with poly-L-lysine (PLL or protamine chlorhydrate for 4 or 24 hrs. Labeling efficiency was evaluated by dextran immunocytochemistry and MRI. Cell proliferation and viability were evaluated in vitro with Ki67 immunocytochemistry and live/dead assays. Ferumoxide-labeled MSCs could be induced to differentiate to adipocytes, osteocytes and chondrocytes. We analyzed ferumoxide retention in MSCs with or without mitomycin C pretreatment. Approximately 95% MSCs were labeled when incubated with ferumoxide for 4 or 24 hrs in the presence of PLL or protamine, whereas labeling of MSCs incubated with ferumoxide alone was poor. Proliferative capacity was maintained in MSCs incubated with ferumoxide and PLL for 4 hrs, however, after 24 hrs it was reduced. MSCs incubated with ferumoxide and protamine were efficiently visualized by MRI; they maintained proliferation and viability for up to 7 days and remained competent to differentiate. After 21 days MSCs pretreated with mitomycin C still showed a large number of ferumoxide-labeled cells. Conclusions The efficient and long lasting uptake and retention of SPIONs by MSCs using a protocol

  15. Waveform control of fuel-cell inverter systems

    OpenAIRE

    Zhu, GR; Wang, KW; Tse, CK; Tan, SC

    2012-01-01

    Fuel-cell power systems comprising single-phase DC/AC inverters draw low-frequency AC ripple currents at twice the output frequency from the fuel cell. Such a 100/120 Hz ripple current may create instability in the fuel cell system, lowers its efficiency, and shortens the lifetime of fuel cell stack. This paper1 presents a waveform control method that can mitigate such a low-frequency ripple current from being drawn from the fuel cell while the fuel-cell system delivers AC power to the load t...

  16. An Enhanced Intelligent Handheld Instrument with Visual Servo Control for 2-DOF Hand Motion Error Compensation

    Directory of Open Access Journals (Sweden)

    Yan Naing Aye

    2013-10-01

    Full Text Available The intelligent handheld instrument, ITrem2, enhances manual positioning accuracy by cancelling erroneous hand movements and, at the same time, provides automatic micromanipulation functions. Visual data is acquired from a high speed monovision camera attached to the optical surgical microscope and acceleration measurements are acquired from the inertial measurement unit (IMU on board ITrem2. Tremor estimation and canceling is implemented via Band-limited Multiple Fourier Linear Combiner (BMFLC filter. The piezoelectric actuated micromanipulator in ITrem2 generates the 3D motion to compensate erroneous hand motion. Preliminary bench-top 2-DOF experiments have been conducted. The error motions simulated by a motion stage is reduced by 67% for multiple frequency oscillatory motions and 56.16% for pre-conditioned recorded physiological tremor.

  17. Selecting category specific visual information: Top-down and bottom-up control of object based attention.

    Science.gov (United States)

    Corradi-Dell'Acqua, Corrado; Fink, Gereon R; Weidner, Ralph

    2015-09-01

    The ability to select, within the complexity of sensory input, the information most relevant for our purposes is influenced by both internal settings (i.e., top-down control) and salient features of external stimuli (i.e., bottom-up control). We here investigated using fMRI the neural underpinning of the interaction of top-down and bottom-up processes, as well as their effects on extrastriate areas processing visual stimuli in a category-selective fashion. We presented photos of bodies or buildings embedded into frequency-matched visual noise to the subjects. Stimulus saliency changed gradually due to an altered degree to which photos stood-out in relation to the surrounding noise (hence generating stronger bottom-up control signals). Top-down settings were manipulated via instruction: participants were asked to attend one stimulus category (i.e., "is there a body?" or "is there a building?"). Highly salient stimuli that were inconsistent with participants' attentional top-down template activated the inferior frontal junction and dorsal parietal regions bilaterally. Stimuli consistent with participants' current attentional set additionally activated insular cortex and the parietal operculum. Furthermore, the extrastriate body area (EBA) exhibited increased neural activity when attention was directed to bodies. However, the latter effect was found only when stimuli were presented at intermediate saliency levels, thus suggesting a top-down modulation of this region only in the presence of weak bottom-up signals. Taken together, our results highlight the role of the inferior frontal junction and posterior parietal regions in integrating bottom-up and top-down attentional control signals. PMID:25735196

  18. Ataxia-telangiectasia cell extracts confer radioresistant DNA synthesis on control cells

    International Nuclear Information System (INIS)

    We have investigated in greater detail the radioresistant DNA synthesis universally observed in cells from patients with ataxia-telangiectasia (A-T). The approach employed in this study was to permeabilize cells with lysolecithin after gamma-irradiation and thus facilitate the introduction of cell extract into these cells. This permeabilization can be reversed by diluting the cells in growth medium. Cells treated in this way show the characteristic inhibition (control cells) or lack of it (A-T cells) after exposure to ionizing radiation. Introduction of A-T cells extracts into control cells prevented the radiation-induced inhibition of DNA synthesis normally observed in these cells. A-T cell extracts did not change the level of radioresistant DNA synthesis in A-T cells. Control cell extracts on the other hand did not influence the pattern of inhibition of DNA synthesis in either cell type. It seems likely that the agent involved is a protein because of its heat lability and sensitivity to trypsin digestion. It has a molecular weight (MW) in the range 20-30 000 D. The development of this assay system for a factor conferring radioresistant DNA synthesis on control cells provides a means of purifying this factor, and ultimately an approach to identifying the gene responsible

  19. Intelligent Control Strategy of Fuel Cell Hybrid Vehicles

    Directory of Open Access Journals (Sweden)

    Abolfazl Hajizadeh

    2011-05-01

    Full Text Available This paper deals a control strategy developed for optimizing the power flow in a Fuel Cell Hybrid Vehicle (FCHV structure. This method implements an on-line power management based on the neuro-fuzzy controller between dual power sources that consist of a battery bank and a fuel cell (FC. This structure included battery and fuel cell and its power train system include an Electric Motor (EM and vehicle dynamics. The proposed control method involves an intelligent controller which captures all of possible operation modes and predicts the driver intention. Moreover, there are local controllers to regulate the set points of each subsystems to reach the best performance and acceptable operation indexes. Simulation results of hybrid system illustrate improvement in the operation efficiency of the FCHV and the battery state of charge and fuel cell utilization factor have been maintained at a reasonable level.

  20. Other ways of seeing: From behavior to neural mechanisms in the online "visual" control of action with sensory substitution.

    Science.gov (United States)

    Proulx, Michael J; Gwinnutt, James; Dell'Erba, Sara; Levy-Tzedek, Shelly; de Sousa, Alexandra A; Brown, David J

    2015-01-01

    Vision is the dominant sense for perception-for-action in humans and other higher primates. Advances in sight restoration now utilize the other intact senses to provide information that is normally sensed visually through sensory substitution to replace missing visual information. Sensory substitution devices translate visual information from a sensor, such as a camera or ultrasound device, into a format that the auditory or tactile systems can detect and process, so the visually impaired can see through hearing or touch. Online control of action is essential for many daily tasks such as pointing, grasping and navigating, and adapting to a sensory substitution device successfully requires extensive learning. Here we review the research on sensory substitution for vision restoration in the context of providing the means of online control for action in the blind or blindfolded. It appears that the use of sensory substitution devices utilizes the neural visual system; this suggests the hypothesis that sensory substitution draws on the same underlying mechanisms as unimpaired visual control of action. Here we review the current state of the art for sensory substitution approaches to object recognition, localization, and navigation, and the potential these approaches have for revealing a metamodal behavioral and neural basis for the online control of action. PMID:26599473

  1. Peptides whose uptake by cells is controllable

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Tao; Tsien, Roger Y

    2014-02-04

    A generic structure for the peptides of the present invention includes A-X-B-C, where C is a cargo moiety, the B portion includes basic amino acids, X is a cleavable linker sequence, and the A portion includes acidic amino acids. The intact structure is not significantly taken up by cells; however, upon extracellular cleavage of X, the B-C portion is taken up, delivering the cargo to targeted cells. Cargo may be, for example, a contrast agent for diagnostic imaging, a chemotherapeutic drug, or a radiation-sensitizer for therapy. Cleavage of X allows separation of A from B, unmasking the normal ability of the basic amino acids in B to drag cargo C into cells near the cleavage event. X is cleaved extracellularly, preferably under physiological conditions. D-amino acids are preferred for the A and B portions, to minimize immunogenicity and nonspecific cleavage by background peptidases or proteases.

  2. Avaliação visual como um programa de controle de qualidade em radiologia odontológica = Visual evaluation as a quality control program in dental radiology

    Directory of Open Access Journals (Sweden)

    Damian, Melissa Feres

    2008-01-01

    Full Text Available Objetivo: Este estudo teve por objetivo avaliar se alterações de densidade e contraste em radiografias, causadas pela degradação das soluções processadoras, podem ser visualmente identificadas. Metodologia: Foram obtidas 60 radiografias periapicais utilizado uma escala de densidades ou um phantom, processadas em uma caixa portátil com líquidos revelador e fixador em progressiva degradação ao longo de 30 dias do experimento. Os filmes da escala de densidades foram usados para avaliar a diminuição percentual de densidade e contraste, e os expostos com o phantom, para a avaliação visual. Nesta última, 18 cirurgiões-dentistas atribuíram notas às radiografias de acordo com a possibilidade de interpretação das imagens. Resultados: Constatou-se que só foram consideradas impróprias para diagnóstico as radiografias que apresentaram perdas médias de 45% de densidade e 62% de contraste. Conclusão: Concluiu-se que a avaliação clínica visual é inadequada para ser executada como um programa único de controle de qualidade de radiografias dentais.

  3. The ubiquitin-proteasome system in glioma cell cycle control

    Directory of Open Access Journals (Sweden)

    Vlachostergios Panagiotis J

    2012-07-01

    Full Text Available Abstract A major determinant of cell fate is regulation of cell cycle. Tight regulation of this process is lost during the course of development and progression of various tumors. The ubiquitin-proteasome system (UPS constitutes a universal protein degradation pathway, essential for the consistent recycling of a plethora of proteins with distinct structural and functional roles within the cell, including cell cycle regulation. High grade tumors, such as glioblastomas have an inherent potential of escaping cell cycle control mechanisms and are often refractory to conventional treatment. Here, we review the association of UPS with several UPS-targeted proteins and pathways involved in regulation of the cell cycle in malignant gliomas, and discuss the potential role of UPS inhibitors in reinstitution of cell cycle control.

  4. Optogenetic Control of Mouse Outer Hair Cells.

    Science.gov (United States)

    Wu, Tao; Ramamoorthy, Sripriya; Wilson, Teresa; Chen, Fangyi; Porsov, Edward; Subhash, Hrebesh; Foster, Sarah; Zhang, Yuan; Omelchenko, Irina; Bateschell, Michael; Wang, Lingyan; Brigande, John V; Jiang, Zhi-Gen; Mao, Tianyi; Nuttall, Alfred L

    2016-01-19

    Normal hearing in mammals depends on sound amplification by outer hair cells (OHCs) presumably by their somatic motility and force production. However, the role of OHC force production in cochlear amplification and frequency tuning are not yet fully understood. Currently, available OHC manipulation techniques for physiological or clinical studies are limited by their invasive nature, lack of precision, and poor temporal-spatial resolution. To overcome these limitations, we explored an optogenetic approach based on channelrhodopsin 2 (ChR-2), a direct light-activated nonselective cation channel originally discovered in Chlamydomonas reinhardtii. Three approaches were compared: 1) adeno-associated virus-mediated in utero transfer of the ChR-2 gene into the developing murine otocyst, 2) expression of ChR-2(H134R) in an auditory cell line (HEI-OC1), and 3) expression of ChR-2 in the OHCs of a mouse line carrying a ChR-2 conditional allele. Whole cell recording showed that blue light (470 nm) elicited the typical nonselective cation current of ChR-2 with reversal potential around zero in both mouse OHCs and HEI-OC1 cells and generated depolarization in both cell types. In addition, pulsed light stimulation (10 Hz) elicited a 1:1 repetitive depolarization and ChR-2 currents in mouse OHCs and HEI-OC1 cells, respectively. The time constant of depolarization in OHCs, 1.45 ms, is 10 times faster than HEI-OC1 cells, which allowed light stimulation up to rates of 10/s to elicit corresponding membrane potential changes. Our study demonstrates that ChR-2 can successfully be expressed in mouse OHCs and HEI-OC1 cells and that these present a typical light-sensitive current and depolarization. However, the amount of ChR-2 current induced in our in vivo experiments was insufficient to result in measurable cochlear effects. PMID:26789771

  5. An indirect adaptive neural control of a visual-based quadrotor robot for pursuing a moving target.

    Science.gov (United States)

    Shirzadeh, Masoud; Amirkhani, Abdollah; Jalali, Aliakbar; Mosavi, Mohammad R

    2015-11-01

    This paper aims to use a visual-based control mechanism to control a quadrotor type aerial robot which is in pursuit of a moving target. The nonlinear nature of a quadrotor, on the one hand, and the difficulty of obtaining an exact model for it, on the other hand, constitute two serious challenges in designing a controller for this UAV. A potential solution for such problems is the use of intelligent control methods such as those that rely on artificial neural networks and other similar approaches. In addition to the two mentioned problems, another problem that emerges due to the moving nature of a target is the uncertainty that exists in the target image. By employing an artificial neural network with a Radial Basis Function (RBF) an indirect adaptive neural controller has been designed for a quadrotor robot in search of a moving target. The results of the simulation for different paths show that the quadrotor has efficiently tracked the moving target. PMID:26521725

  6. P27 in cell cycle control and cancer

    DEFF Research Database (Denmark)

    Møller, Michael Boe

    In order to survive, cells need tight control of cell cycle progression. The control mechanisms are often lost in human cancer cells. The cell cycle is driven forward by cyclin-dependent kinases (CDKs). The CDK inhibitors (CKIs) are important regulators of the CDKs. As the name implies, CKIs were...... distinct NHL entities however, shortened survival seems to correlate with high expression of p27. For definitive assessment of the role played by p27 in lymphomagenesis, and the prognostic value of p27 in these tumors, further studies of distinct NHL entities are needed. This review addresses the function...

  7. Lateral inhibition in the human visual system in patients with glaucoma and healthy subjects: A case-control study

    OpenAIRE

    Francisco G Junoy Montolio; Wilma Meems; Marieke S A Janssens; Lucas Stam; Jansonius, Nomdo M.

    2016-01-01

    textabstractIn glaucoma, the density of retinal ganglion cells is reduced. It is largely unknown how this influences retinal information processing. An increase in spatial summation and a decrease in contrast gain control and contrast adaptation have been reported. A decrease in lateral inhibition might also arise. This could result in a larger than expected response to some stimuli, which could mask ganglion cell loss on functional testing (structure-function discrepancy). The aim of this st...

  8. Lateral Inhibition in the Human Visual System in Patients with Glaucoma and Healthy Subjects: A Case-Control Study

    OpenAIRE

    Junoy Montolio, Francisco G.; Meems, Wilma; Janssens, Marieke S. A.; Stam, Lucas; Jansonius, Nomdo M.

    2016-01-01

    In glaucoma, the density of retinal ganglion cells is reduced. It is largely unknown how this influences retinal information processing. An increase in spatial summation and a decrease in contrast gain control and contrast adaptation have been reported. A decrease in lateral inhibition might also arise. This could result in a larger than expected response to some stimuli, which could mask ganglion cell loss on functional testing (structure-function discrepancy). The aim of this study was to c...

  9. Integrating transcriptional controls for plant cell expansion

    OpenAIRE

    Mockaitis, Keithanne; Estelle, Mark

    2004-01-01

    The plant hormones auxin and brassinosteroid promote cell expansion by regulating gene expression. In addition to independent transcriptional responses generated by the two signals, recent microarray analyses indicate that auxin and brassinosteroid also coordinate the expression of a set of shared target genes.

  10. Epigenetic control of embryonic stem cell fate

    DEFF Research Database (Denmark)

    Christophersen, Nicolaj Strøyer; Helin, Kristian

    2010-01-01

    be induced rapidly to differentiate. Maintaining this balance of stability versus plasticity is a challenge, and extensive studies in recent years have focused on understanding the contributions of transcription factors and epigenetic enzymes to the "stemness" properties of these cells. Identifying...

  11. The control of vascular endothelial cell injury.

    Science.gov (United States)

    Murota, S; Morita, I; Suda, N

    1990-01-01

    The mechanism by which MCI-186 showed a potent cytoprotective effect on the in vitro endothelial cell injury due to 15-HPETE was studied. Stimulation of human leukocytes with various chemical mediators such as TPA, f-Met-Leu-Phe, LTB4, etc. elicited the production of active oxygens, which could be detected by luminol-dependent chemiluminescence. Among the chemical mediators tested, TPA elicited the chemiluminescence the most, and f-Met-Leu-Phe and LTB4 came next. When the leukocytes were directly placed on a monolayer of cultured endothelial cells, followed by stimulating the leukocytes with TPA, severe endothelial cell injury was observed. The effect of TPA was dose dependent. There was good correlation between the active oxygen releasing activity and the cytotoxic activity. When the leukocytes were placed on a filter which was set apart from the monolayer of endothelial cell in a culture dish, and stimulated the leukocytes with TPA, no cytotoxicity was observed. These data strongly suggest that the substance responsible for the cytotoxicity must be a very labile and short-lived substance, presumably active oxygens. On the other hand, MCI-186 was found to have a complete quenching activity to the chemiluminescence due to active oxygens in the TPA-leukocyte system. Taken together, these factors indicate that the potent cytoprotective effect of MCI-186 may be due to its specific radical scavenging activity. PMID:2248437

  12. Adult stem cells in mice : visualization and characterization using genetic mouse models

    NARCIS (Netherlands)

    Snippert, H.J.G.

    2011-01-01

    The onset of each living organism starts with pluripotent stem cells that have the ability to differentiate into all the different cell types of an organism. However, during the earliest stages of development, the pluripotent stem cells will stepwise lose their developmental potential. The cells tha

  13. Feedback Linearized Aircraft Control Using Dynamic Cell Structure

    Science.gov (United States)

    Jorgensen, C. C.

    1998-01-01

    A Dynamic Cell Structure (DCS ) Neural Network was developed which learns a topology representing network (TRN) of F-15 aircraft aerodynamic stability and control derivatives. The network is combined with a feedback linearized tracking controller to produce a robust control architecture capable of handling multiple accident and off-nominal flight scenarios. This paper describes network and its performance for accident scenarios including differential stabilator lock, soft sensor failure, control, stability derivative variation, and turbulence.

  14. A dual-mode turn-on fluorescent BODIPY-based probe for visualization of mercury ions in living cells.

    Science.gov (United States)

    Wang, Yue; Pan, Fuchao; Zhang, Yuanlin; Peng, Fangfang; Huang, Zhentao; Zhang, Weijuan; Zhao, Weili

    2016-08-01

    A novel turn-on fluorescent 8-amino BODIPY-based probe carrying a thiourea unit as the mercury ion recognition unit has been developed. Due to the cascade reaction processes, consecutive color changes reflecting the electronic absorption and emission responses were observed upon addition of increased concentrations of mercury(ii) ions. The likely sensing mechanism was proposed as mercury ion-promoted cyclization and subsequent hydrolysis. The probe displayed a selective response to mercury ions over other metal ions. Additionally, experiments with living Human Hepatoma SMMC-7721 cells to visualize intracellular mercury ions in biological systems were carried out with the probe. PMID:27251011

  15. The magnitude of the effect of calf muscles fatigue on postural control during bipedal quiet standing with vision depends on the eye-visual target distance.

    OpenAIRE

    Vuillerme, Nicolas; Burdet, Cyril; Isableu, Brice; Demetz, Sylvain

    2006-01-01

    The purpose of the present experiment was to investigate whether, with vision, the magnitude of the effect of calf muscles fatigue on postural control during bipedal quiet standing depends on the eye-visual target distance. Twelve young university students were asked to stand upright as immobile as possible in three visual conditions (No vision, Vision 1m and Vision 4m) executed in two conditions of No fatigue and Fatigue of the calf muscles. Centre of foot pressure displacements were recorde...

  16. Visualization of Boundary Layer Separation and Passive Flow Control on Airfoils and Bodies in Wind Tunnel and In-Flight Experiments

    Czech Academy of Sciences Publication Activity Database

    Popelka, Lukáš; Kuklová, J.; Šimurda, David; Součková, Natálie; Matějka, M.; Uruba, Václav

    Moskva: Lomonosov Moscow State University, 2011 - (Znamenskaya, I.), s. 36-37 ISBN 978-5-8279-0092-4. [Pacific Symposium on Flow Visualization and Image Processing /8./. Moskva (RU), 21.08.2011-25.08.2011] R&D Projects: GA MŠk(CZ) 1M06031; GA ČR GA101/08/1112 Institutional research plan: CEZ:AV0Z20760514 Keywords : separation bubble * passive flow control * visualization Subject RIV: BK - Fluid Dynamics

  17. Deleuze's "Postscript on the Societies of Control":A Visual and Textual Engagement

    OpenAIRE

    Birchall, Clare; Hall, Gary; Woodbridge, Peter

    2010-01-01

    This peer-reviewed journal article combines a theoretical text and experimental video exploring Gilles Deleuze's 'societies of control' thesis. The text and video must be viewed together. This article appears in an electronic, open access journal called 'Culture Machine'.

  18. Rac and Rho GTPases in cancer cell motility control

    Directory of Open Access Journals (Sweden)

    Parri Matteo

    2010-09-01

    Full Text Available Abstract Rho GTPases represent a family of small GTP-binding proteins involved in cell cytoskeleton organization, migration, transcription, and proliferation. A common theme of these processes is a dynamic reorganization of actin cytoskeleton which has now emerged as a major switch control mainly carried out by Rho and Rac GTPase subfamilies, playing an acknowledged role in adaptation of cell motility to the microenvironment. Cells exhibit three distinct modes of migration when invading the 3 D environment. Collective motility leads to movement of cohorts of cells which maintain the adherens junctions and move by photolytic degradation of matrix barriers. Single cell mesenchymal-type movement is characterized by an elongated cellular shape and again requires extracellular proteolysis and integrin engagement. In addition it depends on Rac1-mediated cell polarization and lamellipodia formation. Conversely, in amoeboid movement cells have a rounded morphology, the movement is independent from proteases but requires high Rho GTPase to drive elevated levels of actomyosin contractility. These two modes of cell movement are interconvertible and several moving cells, including tumor cells, show an high degree of plasticity in motility styles shifting ad hoc between mesenchymal or amoeboid movements. This review will focus on the role of Rac and Rho small GTPases in cell motility and in the complex relationship driving the reciprocal control between Rac and Rho granting for the opportunistic motile behaviour of aggressive cancer cells. In addition we analyse the role of these GTPases in cancer progression and metastatic dissemination.

  19. Control of stem cell fate by engineering their micro andnanoenvironment

    Institute of Scientific and Technical Information of China (English)

    Michelle F Griffin; Peter E Butler; Alexander M Seifalian; Deepak M Kalaskar

    2015-01-01

    Stem cells are capable of long-term self-renewal anddifferentiation into specialised cell types, making theman ideal candidate for a cell source for regenerativemedicine. The control of stem cell fate has become amajor area of interest in the field of regenerative medicineand therapeutic intervention. Conventional methodsof chemically inducing stem cells into specific lineagesis being challenged by the advances in biomaterialtechnology, with evidence highlighting that materialproperties are capable of driving stem cell fate. Materialsare being designed to mimic the clues stem cells receivein their in vivo stem cell niche including topographicaland chemical instructions. Nanotopographical clues thatmimic the extracellular matrix (ECM) in vivo have shownto regulate stem cell differentiation. The delivery of ECMcomponents on biomaterials in the form of short peptidessequences has also proved successful in directing stem celllineage. Growth factors responsible for controlling stemcell fate in vivo have also been delivered via biomaterialsto provide clues to determine stem cell differentiation. Analternative approach to guide stem cells fate is to providegenetic clues including delivering DNA plasmids andsmall interfering RNAs via scaffolds. This review, aims toprovide an overview of the topographical, chemical andmolecular clues that biomaterials can provide to guidestem cell fate. The promising features and challenges ofsuch approaches will be highlighted, to provide directionsfor future advancements in this exciting area of stem celltranslation for regenerative medicine.

  20. Audio-visual feedback improves the BCI performance in the navigational control of a humanoid robot

    OpenAIRE

    Emmanuele Tidoni; Pierre Gergondet

    2014-01-01

    Advancement in brain computer interfaces (BCI) technology allows people to actively interact in the world through surrogates. Controlling real humanoid robots using BCI as intuitively as we control our body represents a challenge for current research in robotics and neuroscience. In order to successfully interact with the environment the brain integrates multiple sensory cues to form a coherent representation of the world. Cognitive neuroscience studies demonstrate that multisensory integrati...

  1. The Identification and Modeling of Visual Cue Usage in Manual Control Task Experiments

    Science.gov (United States)

    Sweet, Barbara Townsend; Trejo, Leonard J. (Technical Monitor)

    1999-01-01

    Many fields of endeavor require humans to conduct manual control tasks while viewing a perspective scene. Manual control refers to tasks in which continuous, or nearly continuous, control adjustments are required. Examples include flying an aircraft, driving a car, and riding a bicycle. Perspective scenes can arise through natural viewing of the world, simulation of a scene (as in flight simulators), or through imaging devices (such as the cameras on an unmanned aerospace vehicle). Designers frequently have some degree of control over the content and characteristics of a perspective scene; airport designers can choose runway markings, vehicle designers can influence the size and shape of windows, as well as the location of the pilot, and simulator database designers can choose scene complexity and content. Little theoretical framework exists to help designers determine the answers to questions related to perspective scene content. An empirical approach is most commonly used to determine optimum perspective scene configurations. The goal of the research effort described in this dissertation has been to provide a tool for modeling the characteristics of human operators conducting manual control tasks with perspective-scene viewing. This is done for the purpose of providing an algorithmic, as opposed to empirical, method for analyzing the effects of changing perspective scene content for closed-loop manual control tasks.

  2. Peptides whose uptake by cells is controllable

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Tao; Olson, Emilia S.; Whitney, Michael; Tsien, Roger

    2015-07-07

    A generic structure for the peptides of the present invention includes A-X-B-C, where C is a cargo moiety, the B portion includes basic amino acids, X is a cleavable linker sequence, and the A portion includes acidic amino acids. The intact structure is not significantly taken up by cells; however, upon extracellular cleavage of X, the B-C portion is taken up, delivering the cargo to targeted cells. Cargo may be, for example, a contrast agent for diagnostic imaging, a chemotherapeutic drug, or a radiation-sensitizer for therapy. X may be cleaved extracellularly or intracellularly. The molecules of the present invention may be linear, cyclic, branched, or have a mixed structure.

  3. Image-matching during ant navigation occurs through saccade-like body turns controlled by learned visual features.

    Science.gov (United States)

    Lent, David D; Graham, Paul; Collett, Thomas S

    2010-09-14

    Visual memories of landmarks play a major role in guiding the habitual foraging routes of ants and bees, but how these memories engage visuo-motor control systems during guidance is poorly understood. We approach this problem through a study of image matching, a navigational strategy in which insects reach a familiar place by moving so that their current retinal image transforms to match a memorized snapshot of the scene viewed from that place. Analysis of how navigating wood ants correct their course when close to a goal reveals a significant part of the mechanism underlying this transformation. Ants followed a short route to an inconspicuous feeder positioned at a fixed distance from a vertical luminance edge. They responded to an unexpected jump of the edge by turning to face the new feeder position specified by the edge. Importantly, the initial speed of the turn increased linearly with the turn's amplitude. This correlation implies that the ants' turns are driven initially by their prior calculation of the angular difference between the current retinal position of the edge and its desired position in their memorized view. Similar turns keep ants to their path during unperturbed routes. The neural circuitry mediating image-matching is thus concerned not only with the storage of views, but also with making exact comparisons between the retinal positions of a visual feature in a memorized view and of the same feature in the current retinal image. PMID:20805481

  4. A direct computer control concept for mammalian cell fermentation processes

    OpenAIRE

    Büntemeyer, Heino; Marzahl, Rainer; Lehmann, Jürgen

    1994-01-01

    In the last 10 years, new assignments and the special demands of mammalian cells to the culture conditions caused the development of complex small scale fermentation setups. The use of continuous fermentation and cell retention devices requires appropriate process control systems. An arrangement for control and data-acquisition of complex laboratory-scale bioreactors is presented. The fundamental idea was the usage of a standard personal computer, which is connected to pumps, valves and senso...

  5. Control and Communication Network in Hybrid Fuel Cell Vehicles

    Institute of Scientific and Technical Information of China (English)

    朱元; 吴昊; 田光宇; 阳宪惠; 赵立安; 周伟波

    2004-01-01

    This paper describes the control and communication network in fuel cell vehicles, including both the protocol and the hardware.Based on the current protocol (ISO-11898 and SAE J1939), a new practical protocol is proposed and implemented for the control and communication network in fuel cell vehicles.To improve the reliability of data communication and to unify the network management, a new network system based on dual-port RAM is also implemented.

  6. SoftCell: Taking Control of Cellular Core Networks

    OpenAIRE

    Jin, Xin; Li, Li Erran; Vanbever, Laurent; Rexford, Jennifer

    2013-01-01

    Existing cellular networks suffer from inflexible and expensive equipment, and complex control-plane protocols. To address these challenges, we present SoftCell, a scalable architecture for supporting fine-grained policies for mobile devices in cellular core networks. The SoftCell controller realizes high-level service polices by directing traffic over paths that traverse a sequence of middleboxes, optimized to the network conditions and user locations. To ensure scalability, the core switche...

  7. Challenges in tissue engineering - towards cell control inside artificial scaffolds.

    Science.gov (United States)

    Emmert, M; Witzel, P; Heinrich, D

    2016-05-11

    Control of living cells is vital for the survival of organisms. Each cell inside an organism is exposed to diverse external mechano-chemical cues, all coordinated in a spatio-temporal pattern triggering individual cell functions. This complex interplay between external chemical cues and mechanical 3D environments is translated into intracellular signaling loops. Here, we describe how external mechano-chemical cues control cell functions, especially cell migration, and influence intracellular information transport. In particular, this work focuses on the quantitative analysis of (1) intracellular vesicle transport to understand intracellular state changes in response to external cues, (2) cellular sensing of external chemotactic cues, and (3) the cells' ability to migrate in 3D structured environments, artificially fabricated to mimic the 3D environment of tissue in the human body. PMID:27139622

  8. Targeting Homeostatic T Cell Proliferation to Control Beta-Cell Autoimmunity.

    Science.gov (United States)

    Vignali, Debora; Monti, Paolo

    2016-05-01

    Immunomodulation of the autoreactive T cell response is considered a major strategy to control beta-cell autoimmunity, both in the natural history of type 1 diabetes and in islet transplantation, which can be affected by autoimmunity recurrence. So far, these strategies have had modest results, prompting efforts to define novel cellular and molecular targets to control autoreactive T cell expansion and activation. Novel findings highlighted the important role of the homeostatic cytokine interleukin-7 in inducing proliferation and differentiation of autoreactive T cell clones that causes beta-cell autoimmunity. In this review, we discuss recent evidences and novel findings on the role of IL-7 mediated homeostatic T cell proliferation in the process of beta-cell destruction and evidences of how targeting IL-7 and its receptor could be an innovative and effective strategy to control beta-cell autoimmunity. PMID:26983628

  9. Fiber-optic control and thermometry of single-cell thermosensation logic

    Science.gov (United States)

    Fedotov, I. V.; Safronov, N. A.; Ermakova, Yu. G.; Matlashov, M. E.; Sidorov-Biryukov, D. A.; Fedotov, A. B.; Belousov, V. V.; Zheltikov, A. M.

    2015-11-01

    Thermal activation of transient receptor potential (TRP) cation channels is one of the most striking examples of temperature-controlled processes in cell biology. As the evidence indicating the fundamental role of such processes in thermosensation builds at a fast pace, adequately accurate tools that would allow heat receptor logic behind thermosensation to be examined on a single-cell level are in great demand. Here, we demonstrate a specifically designed fiber-optic probe that enables thermal activation with simultaneous online thermometry of individual cells expressing genetically encoded TRP channels. This probe integrates a fiber-optic tract for the delivery of laser light with a two-wire microwave transmission line. A diamond microcrystal fixed on the fiber tip is heated by laser radiation transmitted through the fiber, providing a local heating of a cell culture, enabling a well-controlled TRP-assisted thermal activation of cells. Online local temperature measurements are performed by using the temperature-dependent frequency shift of optically detected magnetic resonance, induced by coupling the microwave field, delivered by the microwave transmission line, to nitrogen—vacancy centers in the diamond microcrystal. Activation of TRP channels is verified by using genetically encoded fluorescence indicators, visualizing an increase in the calcium flow through activated TRP channels.

  10. Cell fate reprogramming by control of intracellular network dynamics

    Science.gov (United States)

    Zanudo, Jorge G. T.; Albert, Reka

    Identifying control strategies for biological networks is paramount for practical applications that involve reprogramming a cell's fate, such as disease therapeutics and stem cell reprogramming. Although the topic of controlling the dynamics of a system has a long history in control theory, most of this work is not directly applicable to intracellular networks. Here we present a network control method that integrates the structural and functional information available for intracellular networks to predict control targets. Formulated in a logical dynamic scheme, our control method takes advantage of certain function-dependent network components and their relation to steady states in order to identify control targets, which are guaranteed to drive any initial state to the target state with 100% effectiveness and need to be applied only transiently for the system to reach and stay in the desired state. We illustrate our method's potential to find intervention targets for cancer treatment and cell differentiation by applying it to a leukemia signaling network and to the network controlling the differentiation of T cells. We find that the predicted control targets are effective in a broad dynamic framework. Moreover, several of the predicted interventions are supported by experiments. This work was supported by NSF Grant PHY 1205840.

  11. Itch expression by Treg cells controls Th2 inflammatory responses

    OpenAIRE

    Jin, Hyung-Seung; Park, Yoon; Elly, Chris; Liu, Yun-Cai

    2013-01-01

    Regulatory T (Treg) cells maintain immune homeostasis by limiting autoimmune and inflammatory responses. Treg differentiation, maintenance, and function are controlled by the transcription factor Foxp3. However, the exact molecular mechanisms underlying Treg cell regulation remain elusive. Here, we show that Treg cell–specific ablation of the E3 ubiquitin ligase Itch in mice caused massive multiorgan lymphocyte infiltration and skin lesions, chronic T cell activation, and the development of s...

  12. Visual bone marrow mesenchymal stem cell transplantation in the repair of spinal cord injury

    OpenAIRE

    Rui-ping Zhang; Cheng Xu; Yin Liu; Jian-ding Li; Jun Xie

    2015-01-01

    An important factor in improving functional recovery from spinal cord injury using stem cells is maximizing the number of transplanted cells at the lesion site. Here, we established a contusion model of spinal cord injury by dropping a weight onto the spinal cord at T 7-8 . Superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells were transplanted into the injured spinal cord via the subarachnoid space. An outer magnetic field was used to successfully guide the labeled cells to...

  13. Shape control and compartmentalization in active colloidal cells.

    Science.gov (United States)

    Spellings, Matthew; Engel, Michael; Klotsa, Daphne; Sabrina, Syeda; Drews, Aaron M; Nguyen, Nguyen H P; Bishop, Kyle J M; Glotzer, Sharon C

    2015-08-25

    Small autonomous machines like biological cells or soft robots can convert energy input into control of function and form. It is desired that this behavior emerges spontaneously and can be easily switched over time. For this purpose we introduce an active matter system that is loosely inspired by biology and which we term an active colloidal cell. The active colloidal cell consists of a boundary and a fluid interior, both of which are built from identical rotating spinners whose activity creates convective flows. Similarly to biological cell motility, which is driven by cytoskeletal components spread throughout the entire volume of the cell, active colloidal cells are characterized by highly distributed energy conversion. We demonstrate that we can control the shape of the active colloidal cell and drive compartmentalization by varying the details of the boundary (hard vs. flexible) and the character of the spinners (passive vs. active). We report buckling of the boundary controlled by the pattern of boundary activity, as well as formation of core-shell and inverted Janus phase-separated configurations within the active cell interior. As the cell size is increased, the inverted Janus configuration spontaneously breaks its mirror symmetry. The result is a bubble-crescent configuration, which alternates between two degenerate states over time and exhibits collective migration of the fluid along the boundary. Our results are obtained using microscopic, non-momentum-conserving Langevin dynamics simulations and verified via a phase-field continuum model coupled to a Navier-Stokes equation. PMID:26253763

  14. Postural Control and Automaticity in Dyslexic Children: The Relationship between Visual Information and Body Sway

    Science.gov (United States)

    Barela, Jose A.; Dias, Josenaldo L.; Godoi, Daniela; Viana, Andre R.; de Freitas, Paulo B.

    2011-01-01

    Difficulty with literacy acquisition is only one of the symptoms of developmental dyslexia. Dyslexic children also show poor motor coordination and postural control. Those problems could be associated with automaticity, i.e., difficulty in performing a task without dispending a fair amount of conscious efforts. If this is the case, dyslexic…

  15. SHARPIN controls the development of regulatory T cells.

    Science.gov (United States)

    Redecke, Vanessa; Chaturvedi, Vandana; Kuriakose, Jeeba; Häcker, Hans

    2016-06-01

    SHARPIN is an essential component of the linear ubiquitin chain assembly complex (LUBAC) complex that controls signalling pathways of various receptors, including the tumour necrosis factor receptor (TNFR), Toll-like receptor (TLR) and antigen receptor, in part by synthesis of linear, non-degrading ubiquitin chains. Consistent with SHARPIN's function in different receptor pathways, the phenotype of SHARPIN-deficient mice is complex, including the development of inflammatory systemic and skin diseases, the latter of which depend on TNFR signal transduction. Given the established function of SHARPIN in primary and malignant B cells, we hypothesized that SHARPIN might also regulate T-cell receptor (TCR) signalling and thereby control T-cell biology. Here, we focus primarily on the role of SHARPIN in T cells, specifically regulatory T (Treg) cells. We found that SHARPIN-deficient (Sharpin(cpdm/cpdm) ) mice have significantly reduced numbers of FOXP3(+) Treg cells in lymphoid organs and the peripheral blood. Competitive reconstitution of irradiated mice with mixed bone marrow from wild-type and SHARPIN-deficient mice revealed an overall reduced thymus population with SHARPIN-deficient cells with almost complete loss of thymic Treg development. Consistent with this cell-intrinsic function of SHARPIN in Treg development, TCR stimulation of SHARPIN-deficient thymocytes revealed reduced activation of nuclear factor-κB and c-Jun N-terminal kinase, establishing a function of SHARPIN in TCR signalling, which may explain the defective Treg development. In turn, in vitro generation and suppressive activity of mature SHARPIN-deficient Treg cells were comparable to wild-type cells, suggesting that maturation, but not function, of SHARPIN-deficient Treg cells is impaired. Taken together, these findings show that SHARPIN controls TCR signalling and is required for efficient generation of Treg cells in vivo, whereas the inhibitory function of mature Treg cells appears to be

  16. Single cell adhesion assay using computer controlled micropipette.

    Directory of Open Access Journals (Sweden)

    Rita Salánki

    Full Text Available Cell adhesion is a fundamental phenomenon vital for all multicellular organisms. Recognition of and adhesion to specific macromolecules is a crucial task of leukocytes to initiate the immune response. To gain statistically reliable information of cell adhesion, large numbers of cells should be measured. However, direct measurement of the adhesion force of single cells is still challenging and today's techniques typically have an extremely low throughput (5-10 cells per day. Here, we introduce a computer controlled micropipette mounted onto a normal inverted microscope for probing single cell interactions with specific macromolecules. We calculated the estimated hydrodynamic lifting force acting on target cells by the numerical simulation of the flow at the micropipette tip. The adhesion force of surface attached cells could be accurately probed by repeating the pick-up process with increasing vacuum applied in the pipette positioned above the cell under investigation. Using the introduced methodology hundreds of cells adhered to specific macromolecules were measured one by one in a relatively short period of time (∼30 min. We blocked nonspecific cell adhesion by the protein non-adhesive PLL-g-PEG polymer. We found that human primary monocytes are less adherent to fibrinogen than their in vitro differentiated descendants: macrophages and dendritic cells, the latter producing the highest average adhesion force. Validation of the here introduced method was achieved by the hydrostatic step-pressure micropipette manipulation technique. Additionally the result was reinforced in standard microfluidic shear stress channels. Nevertheless, automated micropipette gave higher sensitivity and less side-effect than the shear stress channel. Using our technique, the probed single cells can be easily picked up and further investigated by other techniques; a definite advantage of the computer controlled micropipette. Our experiments revealed the existence of a

  17. Real-time visualization of oxygen partial pressures in straight channels of running polymer electrolyte fuel cell with water plugging

    Science.gov (United States)

    Nagase, Katsuya; Suga, Takeo; Nagumo, Yuzo; Uchida, Makoto; Inukai, Junji; Nishide, Hiroyuki; Watanabe, Masahiro

    2015-01-01

    Visualization inside polymer electrolyte fuel cells (PEFCs) for elucidating the reaction distributions is expected to improve the performance, durability, and stability. An oxygen-sensitive film of a luminescent porphyrin was used to visualize the oxygen partial pressures in five straight gas-flow channels of a running PEFC with liquid-water blockages formed at the end of the channels. The blockage greatly lowered and unstabilized the cell voltage. The oxygen partial pressure decreased nearly to 0 kPa in the blocked channel. With a water blockage in a channel, the oxygen partial pressures in the adjacent channels were lowered due to an extra demand of oxygen consumption. When the number of the blocked channels increased, the oxygen partial pressure in the unblocked channels became much lowered. When the water blockages disappeared, the oxygen partial pressures quickly returned to the values before plugging. The influence of the cross flows of air through the gas diffusion layers in straight channels was much smaller than that in serpentine flow channels.

  18. Ocular morphology, topography of ganglion cell distribution and visual resolution of the pilot whale (Globicephala melas)

    OpenAIRE

    Mengual Molina, Rosa María; García Irles, Magdalena; Segovia Huertas, Yolanda; Pertusa, José Francisco

    2015-01-01

    The ocular morphology, morphological characteristics and topography of ganglion cell distribution were studied in four eyes of Globicephala melas to estimate the retinal resolution. The ganglion cell layer was composed of a single row of ganglion cells with a primarily round shape and a cell size which varied from 10 to 75 µm (mean 33.5 µm) in diameter. The typical feature was that 65 % of ganglion cells had a diameter larger than 25 µm, with a similar average size in all regions of the retin...

  19. Energy, control and DNA structure in the living cell

    DEFF Research Database (Denmark)

    Wijker, J.E.; Jensen, Peter Ruhdal; Gomes, A. Vaz; Guiral, M.; Jongsma, A.P.M.; de Waal, A.; Hoving, S.; van Dooren, S.; van der Weijden, C.C.; van Workum, M.; van Heeswijk, W.C.; Molenaar, O.; Wielinga, Pieter; Richard, P.; Diderich, J.; Bakker, B.M.; Teusink, B.; Hemker, M.; Rohwer, J.M.; van der Gugten, A.A.; Kholodenko, B.N.; Westerhoff, H.V.

    Maintenance (let alone growth) of the highly ordered living cell is only possible through the continuous input of free energy. Coupling of energetically downhill processes (such as catabolic reactions) to uphill processes is essential to provide this free energy and is catalyzed by enzymes either...... control cell physiology. Indeed, in the living cell homeostatic control mechanisms might exist for the free-energy transduction pathways so as to prevent perturbation of cellular function when the Gibbs energy supply is compromised. This presentation addresses the extent to which the intracellular ATP...

  20. Visualization of cell death in mice with focal cerebral ischemia using fluorescent annexin A5, propidium iodide, and TUNEL staining.

    Science.gov (United States)

    Bahmani, Peyman; Schellenberger, Eyk; Klohs, Jan; Steinbrink, Jens; Cordell, Ryan; Zille, Marietta; Müller, Jochen; Harhausen, Denise; Hofstra, Leo; Reutelingsperger, Chris; Farr, Tracy Deanne; Dirnagl, Ulrich; Wunder, Andreas

    2011-05-01

    To monitor stroke-induced brain damage and assess neuroprotective therapies, specific imaging of cell death after cerebral ischemia in a noninvasive manner is highly desirable. Annexin A5 has been suggested as a marker for imaging cell death under various disease conditions including stroke. In this study, C57BL6/N mice received middle cerebral artery occlusion (MCAO) and were injected intravenously with either active or inactive Cy5.5-annexin A5 48 hours after reperfusion. Some mice also received propidium iodide (PI), a cell integrity marker. Only in mice receiving active Cy5.5-annexin A5 were fluorescence intensities significantly higher over the hemisphere ipsilateral to MCAO than on the contralateral side. This was detected noninvasively and ex vivo 4 and 8 hours after injection. The majority of cells positive for fluorescent annexin A5 were also positive for PI and fragmented DNA as detected by terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL) staining. This study demonstrates the high specificity of annexin A5 for visualization of cell death in a mouse model of stroke. To our knowledge, this is the first study to compare the distribution of injected active and inactive annexin A5, PI, and TUNEL staining. It provides important information on the experimental and potential clinical applications of annexin A5-based imaging agents in stroke. PMID:21245871

  1. The control and execution of programmed cell death

    International Nuclear Information System (INIS)

    Apoptosis or programmed cell death is a highly conserved genetically controlled response of metazoan cells to commit suicide. Non apoptotic programmed cell death seems to operate in single celled eukaryotes implying that evolution of PCD has preceded the evolution of multicellularity. PCD plays a crucial role in the regulation of cellular and tissue homeostasis and any aberrations in apoptosis leads to several diseases including cancer, neurodegenerative disorders and AIDS. The mechanisms by which apoptosis is controlled are varied. In some cells, members of bcl-2 family or p53 are crucial for regulating the apoptosis programme, whereas in other cells Fas ligand is more important. bcl-2 family members have a prime role in the regulation of cell death at all stages including development, whereas cell death during development is independent of p53. bcl-2 family members being localized on the outer mitochondrial membrane, control the mitochondrial homeostasis and cytochrome c redistribution and thereby regulate the cell death process. p53 promotes DNA damage mediated cell death after growth arrest and failed DNA repair. Caspases play a key role in the execution of cell death by mediating highly specific cleavages of crucial cellular proteins collectively manifesting the apoptotic phenotype. Protein inhibitors like crm A, p35 and IAPs could prevent/control apoptosis induced by a broad array of cell death stimuli by several mechanisms specially interfering in caspase activation or caspase activity. Among endonucleases, caspase activated DNase (CAD) plays a crucial role in DNA fragmentation, a biochemical hallmark of apoptosis. As regulation of cell death seems to be as complex as regulation of cell proliferation, multiple kinase mediated regulatory mechanisms might control the apoptotic process. Thus, in spite of intensive research over the past few years, the field of apoptosis still remains fertile to unravel among others, the molecular mechanisms of cytochrome c

  2. Visualization of Software and Systems as Support Mechanism for Integrated Software Project Control

    OpenAIRE

    Liggesmeyer, Peter; Heidrich, Jens; Münch, Jürgen; Kalcklösch, Robert; Barthel, Henning; Zeckzer, Dirk

    2014-01-01

    Many software development organizations still lack support for obtaining intellectual control over their software development processes and for determining the performance of their processes and the quality of the produced products. Systematic support for detecting and reacting to critical process and product states in order to achieve planned goals is usually missing. One means to institutionalize measurement on the basis of explicit models is the development and establishment of a so-called...

  3. A Framework for Coupling Visual Control and Active Structure from Motion

    OpenAIRE

    Spica, Riccardo; Robuffo Giordano, Paolo; Chaumette, François

    2015-01-01

    International audience In most sensor-based robotic applications, the robot state can only be partially retrieved from onboard sensors and the use of estimation strategies is necessary for recovering online an approximation of any 'missing information' required to accurately control the robot action. With the exception of some trivial cases, however, the relationship between the sensor readings and the robot state is often nonlinear. As a consequence, and regardless of the particular estim...

  4. Integration of 3D vision based structure estimation and visual robot control

    OpenAIRE

    Prljaca, Naser

    1995-01-01

    Enabling robot manipulators to manipulate and/or recognise arbitrarily placed 3D objects under sensory control is one of the key issues in robotics. Such robot sensors should be capable of providing 3D information about objects in order to accomplish the above mentioned tasks. Such robot sensors should also provide the means for multisensor or multimeasurement integration. Finally, such 3D information should be efficiently used for performing desired tasks. This work develops a novel comp...

  5. Sliding-Mode Control of PEM Fuel Cells

    CERN Document Server

    Kunusch, Cristian; Mayosky, Miguel

    2012-01-01

    Recent advances in catalysis technologies and new materials make fuel cells an economically appealing and clean energy source with massive market potential in portable devices, home power generation and the automotive industry. Among the more promising fuel-cell technologies are proton exchange membrane fuel cells (PEMFCs). Sliding-Mode Control of PEM Fuel Cells demonstrates the application of higher-order sliding-mode control to PEMFC dynamics. Fuel-cell dynamics are often highly nonlinear and the text shows the advantages of sliding modes in terms of robustness to external disturbance, modelling error and system-parametric disturbance using higher-order control to reduce chattering. Divided into two parts, the book first introduces the theory of fuel cells and sliding-mode control. It begins by contextualising PEMFCs both in terms of their development and within the hydrogen economy and today’s energy production situation as a whole. The reader is then guided through a discussion of fuel-cell operation pr...

  6. Control assembly for controlling a fuel cell system during shutdown and restart

    Science.gov (United States)

    Venkataraman, Ramki; Berntsen, George; Carlson, Glenn L.; Farooque, Mohammad; Beachy, Dan; Peterhans, Stefan; Bischoff, Manfred

    2010-06-15

    A fuel cell system and method in which the fuel cell system receives and an input oxidant gas and an input fuel gas, and in which a fuel processing assembly is provided and is adapted to at least humidify the input fuel gas which is to be supplied to the anode of the fuel cell of the system whose cathode receives the oxidant input gas via an anode oxidizing assembly which is adapted to couple the output of the anode of the fuel cell to the inlet of the cathode of the fuel cell during normal operation, shutdown and restart of the fuel cell system, and in which a control assembly is further provided and is adapted to respond to shutdown of the fuel cell system during which input fuel gas and input oxidant gas cease to be received by the fuel cell system, the control assembly being further adapted to, when the fuel cell system is shut down: control the fuel cell system so as to enable a purging gas to be able to flow through the fuel processing assembly to remove humidified fuel gas from the processing assembly and to enable a purging gas to be able to flow through the anode of the fuel cell.

  7. COMPARISON OF VISUAL CRYPTOGRAPHIC SCHEMES

    OpenAIRE

    M.Amarnath Reddy,; P.Shanthi Bala,; Aghila, G.

    2011-01-01

    Visual cryptography technique allows the visual information to be encrypted in such a way that their decryption can be performed by human visual system. This technique used to encrypt a image into shares such that stacking a sufficient number of shares reveals the secret images. In visual cryptography there are different technique like sub pixel, error diffusion, Boolean operation etc. Visual cryptography can be applied for copyright for images, access control to user images, Visual authentic...

  8. Influence of the metabolic control on latency values of visual evoked potentials (VEP) in patients with diabetes mellitus type 1.

    Science.gov (United States)

    Matanovic, Dragana; Popovic, Srdjan; Parapid, Biljana; Petronic, Ivana; Cirovic, Dragana; Nikolic, Dejan

    2012-12-01

    The aim of our study was to investigate the relationship between the metabolic control parameters of diabetes mellitus (glycemia and HbA1c) and visual evoked potentials (VEP) latency values. The study included 61 patients with diabetes mellitus type 1 that were hospitalized at the Clinic for Endocrinology, Diabetes and Metabolic Diseases due to the poor metabolic control. All patients were divided into 3 groups. Group 1 consisted of patients on conventional insulin therapy (CT); Group 2 included patients on CT at the moment of hospitalization, with a change towards intensified insulin therapy (IIT); and Group 3 consisted of patients on IIT. Patients with diabetic retinopathy (DR) were excluded from the study. Metabolic control (glycemia and HbA1c) and VEP parameters were compared at the beginning of the study and six months later. After six months of strict glycoregulation, significant improvement in VEP parameters was followed by significant improvement of evaluated parameters of metabolic control. We found statistically significant reduction in frequency of pathological VEP findings, prolonged P100 latency and low amplitude potentials in Group 2, while in Groups 1 and 3 we found that these parameters did not significantly changed but the frequencies were lower. The VEP testing is a noninvasive diagnostic procedure which may help in early diagnosis of DR, prognosis during the metabolic control and treatment. If changes in the retina could be detected before DR is noticed using this noninvasive diagnostic procedure and include patients in a strict glycoregulation, we could be in the position to prevent serious complications that may cause blindness. PMID:23479458

  9. Translaminar Inhibitory Cells Recruited by Layer 6 Cortico-Thalamic Neurons Suppress Visual Cortex

    OpenAIRE

    Bortone, Dante S.; Olsen, Shawn R.; Scanziani, Massimo

    2014-01-01

    In layer 6 (L6), a principal output layer of the mammalian cerebral cortex, a population of excitatory neurons defined by the NTSR1-Cre mouse line inhibit cortical responses to visual stimuli. Here we show that of the two major types of excitatory neurons existing in L6, the NTSR1-Cre line selectively targets those whose axon innervate both cortex and thalamus and not those whose axons remain within the cortex. These cortico-thalamic neurons mediate widespread inhibition across all cortical l...

  10. Machine-Part cell formation through visual decipherable clustering of Self Organizing Map

    OpenAIRE

    Chattopadhyay, Manojit; Chattopadhyay, Surajit; Dan, Pranab K

    2011-01-01

    Machine-part cell formation is used in cellular manufacturing in order to process a large variety, quality, lower work in process levels, reducing manufacturing lead-time and customer response time while retaining flexibility for new products. This paper presents a new and novel approach for obtaining machine cells and part families. In the cellular manufacturing the fundamental problem is the formation of part families and machine cells. The present paper deals with the Self Organising Map (...

  11. Visual control of the Parrot drone with OpenCV, Ros and Gazebo Simulator

    OpenAIRE

    Banach, Artur

    2016-01-01

    Drones are becoming more and more popular these days. There are multiple tasks and ideas that can be implemented to them. One of them is the idea described in that work. The aim of the project was creating a software in C++ in ROS that will control the Parrot Drone simulated in Gazebo Simulator. The drone movements are stimulated by the orange ball movements in front of the camera (the picture below). As it is presented on the diagram below, there were needed: Ardrone Autonomy Package (dro...

  12. Cells on corrugations for pollution control

    International Nuclear Information System (INIS)

    Old cardboard boxes constitute 12% of landfills. White rot fungus can be grown on the boxes and buried in contaminated soil. The fungus needs air which is entrapped in the corrugations. The fungus is sensitive to large amounts of TNT but it is protected when inside the corrugations. Fast food containers are filling landfills. Lactic acid production needs air and the polymers are biodegradable. When corrugations are put in a half full rotary unit, holes in the valleys make drops, and mass transfer to drops is much higher than to a flat surface. A lab corrugator has been made from an old washing machine wringer, so other fibers can be corrugated. When the bacterium, Zymomonas mobilis is grown on Tyvek fiber, lead and six valent chromium are removed from wastewater in a few seconds. Zymomonas on rotating fibers converts sugar to alcohol in 10--15 minutes and when a light is shown into flat rotating discs, it hits a thin moving film to destroy dioxin. Salt on roads causes millions of dollars damage to bridges and cars but calcium magnesium acetate is not corrosive and can be made with cells on rotating fibers

  13. Modeling, analysis and control of fuel cell hybrid power systems

    Science.gov (United States)

    Suh, Kyung Won

    Transient performance is a key characteristic of fuel cells, that is sometimes more critical than efficiency, due to the importance of accepting unpredictable electric loads. To fulfill the transient requirement in vehicle propulsion and portable fuel cell applications, a fuel cell stack is typically coupled with a battery through a DC/DC converter to form a hybrid power system. Although many power management strategies already exist, they all rely on low level controllers that realize the power split. In this dissertation we design controllers that realize various power split strategies by directly manipulating physical actuators (low level commands). We maintain the causality of the electric dynamics (voltage and current) and investigate how the electric architecture affects the hybridization level and the power management. We first establish the performance limitations associated with a stand-alone and power-autonomous fuel cell system that is not supplemented by an additional energy storage and powers all its auxiliary components by itself. Specifically, we examine the transient performance in fuel cell power delivery as it is limited by the air supplied by a compressor driven by the fuel cell itself. The performance limitations arise from the intrinsic coupling in the fluid and electrical domain between the compressor and the fuel cell stack. Feedforward and feedback control strategies are used to demonstrate these limitations analytically and with simulations. Experimental tests on a small commercial fuel cell auxiliary power unit (APU) confirm the dynamics and the identified limitations. The dynamics associated with the integration of a fuel cell system and a DC/DC converter is then investigated. Decentralized and fully centralized (using linear quadratic techniques) controllers are designed to regulate the power system voltage and to prevent fuel cell oxygen starvation. Regulating these two performance variables is a difficult task and requires a compromise

  14. Visualization of immediate immune responses to pioneer metastatic cells in the lung.

    Science.gov (United States)

    Headley, Mark B; Bins, Adriaan; Nip, Alyssa; Roberts, Edward W; Looney, Mark R; Gerard, Audrey; Krummel, Matthew F

    2016-03-24

    Lung metastasis is the lethal determinant in many cancers and a number of lines of evidence point to monocytes and macrophages having key roles in its development. Yet little is known about the immediate fate of incoming tumour cells as they colonize this tissue, and even less known about how they make first contact with the immune system. Primary tumours liberate circulating tumour cells (CTCs) into the blood and we have developed a stable intravital two-photon lung imaging model in mice for direct observation of the arrival of CTCs and subsequent host interaction. Here we show dynamic generation of tumour microparticles in shear flow in the capillaries within minutes of CTC entry. Rather than dispersing under flow, many of these microparticles remain attached to the lung vasculature or independently migrate along the inner walls of vessels. Using fluorescent lineage reporters and flow cytometry, we observed 'waves' of distinct myeloid cell subsets that load differentially and sequentially with this CTC-derived material. Many of these tumour-ingesting myeloid cells collectively accumulated in the lung interstitium along with the successful metastatic cells and, as previously understood, promote the development of successful metastases from surviving tumour cells. Although the numbers of these cells rise globally in the lung with metastatic exposure and ingesting myeloid cells undergo phenotypic changes associated with microparticle ingestion, a consistently sparse population of resident conventional dendritic cells, among the last cells to interact with CTCs, confer anti-metastatic protection. This work reveals that CTC fragmentation generates immune-interacting intermediates, and defines a competitive relationship between phagocyte populations for tumour loading during metastatic cell seeding. PMID:26982733

  15. Wnt signaling control of bone cell apoptosis

    Institute of Scientific and Technical Information of China (English)

    Peter V N Bodine

    2008-01-01

    Wnts are a large family of growth factors that mediate essential biological processes like embryogenesis, morphogenesis and organogenesis. These proteins also play a role in oncogenesis, and they regulate apoptosis in many tissues. Wnts bind to a membrane receptor complex comprised of a frizzled (FZD) G-protein-coupled receptor and a low-density , lipoprotein (LDL) receptor-related protein (LRP). The formation of this ligand-receptor complex initiates a number of signaling cascades that include the canonical/beta-catenin pathway as well as several noncanonical pathways. In recent years, canonical Wnt signaling has been reported to play a significant role in the control of bone formation. Clinical studies have found that mutations in LRP-5 are associated with reduced bone mineral density (BMD) and fractures. Investigations of knockout and transgenic mouse models of Wnt pathway components have shown that canonical Wnt signaling modulates most aspects of osteoblast physiology including proliferation, differentiation, function and apoptosis. Transgenic mice expressing a gain of function mutant of LRP-5 in bone, or mice lacking the Wnt antagonist secreted frizzled-related protein-1, exhibit elevated BMD and suppressed osteoblast apoptosis. In addition, preclinical studies with pharmacologic compounds such as those that inhibit glycogen synthase kinase-3p support the importance of the canonical Wnt pathway in modulation of bone formation and osteoblast apoptosis.

  16. visual bone marrow mesenchymal stem cell transplantation in the repair of spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Rui-ping Zhang; Cheng Xu; Yin Liu; Jian-ding Li; Jun Xie

    2015-01-01

    An important factor in improving functional recovery from spinal cord injury using stem cells is maximizing the number of transplanted cells at the lesion site. Here, we established a contusion model of spinal cord injury by dropping a weight onto the spinal cord at T7–8. Superparamagnet-ic iron oxide-labeled bone marrow mesenchymal stem cells were transplanted into the injured spinal cordvia the subarachnoid space. An outer magnetic ifeld was used to successfully guide the labeled cells to the lesion site. Prussian blue staining showed that more bone marrow mesen-chymal stem cells reached the lesion site in these rats than in those without magnetic guidance or superparamagnetic iron oxide labeling, and immunolfuorescence revealed a greater number of complete axons at the lesion site. Moreover, the Basso, Beattie and Bresnahan (BBB) locomotor rating scale scores were the highest in rats with superparamagnetic labeling and magnetic guid-ance. Our data conifrm that superparamagnetic iron oxide nanoparticles effectively label bone marrow mesenchymal stem cells and impart sufficient magnetism to respond to the external magnetic ifeld guides. More importantly, superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells can be dynamically and non-invasively trackedin vivo using magnetic resonance imaging. Superparamagnetic iron oxide labeling of bone marrow mesenchymal stem cells coupled with magnetic guidance offers a promising avenue for the clinical treatment of spinal cord injury.

  17. Fabrication of gold nanodot arrays on a transparent substrate as a nanobioplatform for label-free visualization of living cells

    International Nuclear Information System (INIS)

    Two-dimensional gold (Au) nanodot arrays on a transparent substrate were fabricated for imaging of living cells. A nanoporous alumina mask with large-area coverage capability was prepared by a two-step chemical wet etching process after a second anodization. Highly ordered Au nanodot arrays were formed on indium-tin-oxide (ITO) glass using very thin nanoporous alumina of approximately 200 nm thickness as an evaporation mask. The large-area Au nanodot arrays on ITO glass were modified with RGD peptide (arginine; glycine; aspartic acid) containing a cysteine (Cys) residue and then used to immobilize human cancer HeLa cells, the morphology of which was observed by confocal microscopy. The confocal micrographs of living HeLa cells on Au nanodot arrays revealed enhanced contrast and resolution, which enabled discernment of cytoplasmic organelles more clearly. These results suggest that two-dimensional Au nanodot arrays modified with RGD peptide on ITO glass have potential as a biocompatible nanobioplatform for the label-free visualization and adhesion of living cells.

  18. Vibration control of an IVVS long-reach deployer using unknown visual features from inside the ITER vessel

    International Nuclear Information System (INIS)

    The In-Vessel Viewing System (IVVS) project assumes that a long reach deployer equipped with a probe penetrates the ITER chamber to perform periodic inspections. By giving the operator the capability and flexibility to examine unplanned targets, man-in-the-loop technology would be very helpful. But vibrations due to the high flexibility of the structure are probably the main problem in such a master-slave mode, which therefore needs the integration of a high level compensation scheme. However the ITER RH equipment will be confronted with strong electromagnetic interferences as well as a cumulated radiation dose up to several MGy. Short of costly developments, these constraints limit the use of dedicated electronics such as accelerometers or strain gauges. Our main idea is to control the vibrational behaviour of the flexible carrier without considering any extra sensor apart from its embedded probe. In this pre-study we propose to use the kind of rad-hardened viewing system already developed for the AIA demonstrator in order to feed an oscillation observer with visual information. The visual data are extracted from the environment without a priori knowledge of the examined scene. Our approach is quite open-ended and can be extended to other flexible systems. Moreover it has been designed to damp the oscillatory behaviour of the arm whatever its origins may be. As a consequence it should yield good performance when vibrations result from a critical trajectory imposed by the operator, from an interaction with the environment, or from internal dynamics of the carried process, e.g. the rotating prism of the IVVS 3D Inspection System. Experimental results validate the proposed strategy.

  19. Frequency lock closed-loop control of a separated flow using visual feedback

    CERN Document Server

    Gautier, N

    2013-01-01

    In this study, a simple model based closed-loop algorithm is used to control the separated flow downstream a backward-facing step. It has been shown in previous studies that the recirculation bubble can be minimized when exciting the shear layer at its natural Kelvin-Helmholtz instability frequency. In this experiment, the natural shedding frequency is identified through real-time analysis of 2D velocity fields. Actuation (pulsed jet) is then locked on this frequency. If flow characteristics stray too far from a set point, shedding frequency is updated and actuation changed. The present work demonstrates the efficacy and robustness of this approach in reducing recirculation while Reynolds number is randomly varied between 1400 and 2800.

  20. Comparison of postural control between healthy subjects and individuals with nonspecific low back pain during exposure to visual stimulus

    Institute of Scientific and Technical Information of China (English)

    Li Rui; Wang Ninghua; Yan Xiang; Wei Kunlin

    2014-01-01

    Background Low back pain (LBP) is a common clinical problem.Many researchers have demonstrated that LBP disorders have difference in sensory strategies for postural control.Optokinetic stimulation (OKS) of optic flow has been widely applied to study its effect on vision,but has not been applied to LBP.Here we used OKS on different surfaces to investigate the characteristics of chronic nonspecific LBP (CNLBP) posture control,so as to provide new theoretical and experimental data for further recognizing CNLBP and enriching its treatment.Methods Fifteen individuals with CNLBP (age range 25-40 years) and 15 age and gender-matched control subjects were recruited.Each subject,while standing on a stable or soft surface,was exposed to random-dot patterns projected on a large screen,with the dots displaying expansion (+) and contraction (-) and velocities including 80°,40°,and 20° per second.The visual stimulus used a "stimuli-interval" pattern.The peak velocity,different phases' standard deviation (SD) of the anterior-posterior centre of pressure (COP) displacements and the total length of the medial-lateral COP sway (LML) for stable surface and soft surface were recorded by force platform.Results The main effect of surface on all parameters was significant,while the main effect of group and OKS showed no significance with the exception of peak velocity (F(3,95)=3.6,P=0.01) and A2 (F(5,140)=9.34,P <0.01) for which the effect of OKS was significant.The interactions of group by OKS of A2 (F(5,140)=3.65,P <0.01) and group by surface by OKS (F(5,140)=2.83,P=-0.02),and surface by OKS of A1 and A3 (P <0.05) were significant.It was reported that significantly more SD in amplitude in the T2 phase was seen in persons with CNLBP when confronting the + 40 stimuli on the soft surface (P <0.05) compared to healthy individuals.Conclusions There was no significance between persons with CNLBP and healthy people when using the stable surface.Subjects with LBP showed decreased

  1. Construct hepatic analog by cell-matrix controlled assembly technology

    Institute of Scientific and Technical Information of China (English)

    LIU Haixia; YAN Yongnian; WANG Xiaohong; CHENG Jie; LIN Feng; XIONG Zhuo; Wu Rendong

    2006-01-01

    A mixture of hepatic cells and chitosan/gelatin solution was deposited to construct a hepatic analog by way of layer-by-layer deposition technique using a home-made devise. The size and cell concentration of the analogs can be controlled freely. Approximately 90% of the hepatic cells remained viable under 0.2 Mpa extrusion pressure. Cultured in vitro 8 weeks before animal test, hepatic cells in structure maintained their phenotype and kept proliferating, and albumin and other secretion of the cells increased. Cords and hepaton-like structures were observed after culture for 20 d. These results indicate that hepatic cells could be assembled directly into a 3D viable structure and expanded to form a hepatic organoid. This accomplishment is considered to be an interesting means for the fabrication of liver replacements.

  2. Human intestinal dendritic cells as controllers of mucosal immunity

    Directory of Open Access Journals (Sweden)

    David Bernardo

    2013-06-01

    Full Text Available Dendritic cells are the most potent, professional antigen-presenting cells in the body; following antigen presentation they control the type (proinflammatory/regulatory of immune response that will take place, as well as its location. Given their high plasticity and maturation ability in response to local danger signals derived from innate immunity, dendritic cells are key actors in the connection between innate immunity and adaptive immunity responses. In the gut dendritic cells control immune tolerance mechanisms against food and/or commensal flora antigens, and are also capable of initiating an active immune response in the presence of invading pathogens. Dendritic cells are thus highly efficient in controlling the delicate balance between tolerance and immunity in an environment so rich in antigens as the gut, and any factor involving these cells may impact their function, ultimately leading to the development of bowel conditions such as celiac disease or inflammatory bowel disease. In this review we shall summarize our understanding of human intestinal dendritic cells, their ability to express and induce migration markers, the various environmental factors modulating their properties, their subsets in the gut, and the problems entailed by their study, including identification strategies, differences between humans and murine models, and phenotypical variations along the gastrointestinal tract.

  3. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion.

    Directory of Open Access Journals (Sweden)

    Aretha Fiebig

    2014-01-01

    Full Text Available In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ. Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.

  4. Fuzzy Control of Polymer Fuel Cell for Attract Maximum Power

    Directory of Open Access Journals (Sweden)

    Zahra Nejati

    2014-01-01

    Full Text Available Polymer fuel cell is one of the most attractive of fuel cell from point of the design and operation and also in comparison with other types of fuel cell, for a weight and size, polymer fuel cell produces more power. But however, one of the problems to use of this system is its low efficiency .To overcome the low efficiency of the fuel cell polymer in this paper is tried to used from maximum power point tracking. According to the characteristic of the flow –power the fuel cell, which is a non-linear curve and has a maximum point and use of the fuzzy controller and the proper selection of input and output membership functions trying to the System always works at maximum power. For this purpose, a chopper is used between the fuel cell and the load and to adjust the duty cycle of the applied signal to it is applied the fuzzy-TSK type controller that Its inputs are stream slope and slope changes. The results show that this controller has a good performance and that is faster compared with the perturbation and observation method.

  5. WLAN visual sensor networking

    Science.gov (United States)

    Kostrzewski, Andrew A.; Wang, Wenjian; Jannson, Tomasz P.

    2002-12-01

    This paper presents a discussion on constructing a wireless ad hoc network using unattended ground visual sensors. The IEEE 802.11 WLAN standard is used to implement a single-hop ad hoc network because of its simplicity. The bandwidth allocation and traffic control between visual sensors is coordinated by the Medium Access Control (MAC) protocol. A ground visual sensor tower is designed for the networking purpose with specially designed video compression, power management, and network module to achieve maximum thoroughput

  6. Gender-Specificity of Initial and Controlled Visual Attention to Sexual Stimuli in Androphilic Women and Gynephilic Men

    Science.gov (United States)

    Dawson, Samantha J.; Chivers, Meredith L.

    2016-01-01

    Research across groups and methods consistently finds a gender difference in patterns of specificity of genital response; however, empirically supported mechanisms to explain this difference are lacking. The information-processing model of sexual arousal posits that automatic and controlled cognitive processes are requisite for the generation of sexual responses. Androphilic women’s gender-nonspecific response patterns may be the result of sexually-relevant cues that are common to both preferred and nonpreferred genders capturing attention and initiating an automatic sexual response, whereas men’s attentional system may be biased towards the detection and response to sexually-preferred cues only. In the present study, we used eye tracking to assess visual attention to sexually-preferred and nonpreferred cues in a sample of androphilic women and gynephilic men. Results support predictions from the information-processing model regarding gendered processing of sexual stimuli in men and women. Men’s initial attention patterns were gender-specific, whereas women’s were nonspecific. In contrast, both men and women exhibited gender-specific patterns of controlled attention, although this effect was stronger among men. Finally, measures of attention and self-reported attraction were positively related in both men and women. These findings are discussed in the context of the information-processing model and evolutionary mechanisms that may have evolved to promote gendered attentional systems. PMID:27088358

  7. EMG and kinematic analysis of sensorimotor control for patients after stroke using cyclic voluntary movement with visual feedback

    Directory of Open Access Journals (Sweden)

    Song Rong

    2013-02-01

    Full Text Available Abstract Background Clinical scales are often used to evaluate upper-limb deficits. The objective of this study is to investigate the parameters during voluntary arm tracking at different velocities for evaluating motor control performance after stroke. Methods Eight hemiplegic chronic stroke subjects were recruited to perform voluntary movements of elbow flexion and extension by following sinusoidal trajectories from 30 deg to 90 deg at six velocities in the horizontal plane by completing 3, 6, 8, 12, 15, 18 flexion and extension cycles in 36 seconds in a single trial, and the peak velocities ranged from 15.7 to 94.2 deg/s. The actual elbow angle and the target position were displayed as real-time visual feedback. The angular displacement of the arm and electromyographic (EMG signals of biceps and triceps were captured to evaluate the sensorimotor control of the affected and unaffected side. Results The results showed significant differences in the root mean square error (RMSE, response delay (RD and cocontraction index (CI when the affected and unaffected sides were compared during the arm tracking experiment (P Conclusions The method and parameters have potential for clinical use in quantitatively evaluating the sensorimotor deficiencies for patients after stroke about the accuracy of motion, response delay and cocontraction between muscle pairs.

  8. Gender-Specificity of Initial and Controlled Visual Attention to Sexual Stimuli in Androphilic Women and Gynephilic Men.

    Directory of Open Access Journals (Sweden)

    Samantha J Dawson

    Full Text Available Research across groups and methods consistently finds a gender difference in patterns of specificity of genital response; however, empirically supported mechanisms to explain this difference are lacking. The information-processing model of sexual arousal posits that automatic and controlled cognitive processes are requisite for the generation of sexual responses. Androphilic women's gender-nonspecific response patterns may be the result of sexually-relevant cues that are common to both preferred and nonpreferred genders capturing attention and initiating an automatic sexual response, whereas men's attentional system may be biased towards the detection and response to sexually-preferred cues only. In the present study, we used eye tracking to assess visual attention to sexually-preferred and nonpreferred cues in a sample of androphilic women and gynephilic men. Results support predictions from the information-processing model regarding gendered processing of sexual stimuli in men and women. Men's initial attention patterns were gender-specific, whereas women's were nonspecific. In contrast, both men and women exhibited gender-specific patterns of controlled attention, although this effect was stronger among men. Finally, measures of attention and self-reported attraction were positively related in both men and women. These findings are discussed in the context of the information-processing model and evolutionary mechanisms that may have evolved to promote gendered attentional systems.

  9. Automatic Control of Gene Expression in Mammalian Cells.

    Science.gov (United States)

    Fracassi, Chiara; Postiglione, Lorena; Fiore, Gianfranco; di Bernardo, Diego

    2016-04-15

    Automatic control of gene expression in living cells is paramount importance to characterize both endogenous gene regulatory networks and synthetic circuits. In addition, such a technology can be used to maintain the expression of synthetic circuit components in an optimal range in order to ensure reliable performance. Here we present a microfluidics-based method to automatically control gene expression from the tetracycline-inducible promoter in mammalian cells in real time. Our approach is based on the negative-feedback control engineering paradigm. We validated our method in a monoclonal population of cells constitutively expressing a fluorescent reporter protein (d2EYFP) downstream of a minimal CMV promoter with seven tet-responsive operator motifs (CMV-TET). These cells also constitutively express the tetracycline transactivator protein (tTA). In cells grown in standard growth medium, tTA is able to bind the CMV-TET promoter, causing d2EYFP to be maximally expressed. Upon addition of tetracycline to the culture medium, tTA detaches from the CMV-TET promoter, thus preventing d2EYFP expression. We tested two different model-independent control algorithms (relay and proportional-integral (PI)) to force a monoclonal population of cells to express an intermediate level of d2EYFP equal to 50% of its maximum expression level for up to 3500 min. The control input is either tetracycline-rich or standard growth medium. We demonstrated that both the relay and PI controllers can regulate gene expression at the desired level, despite oscillations (dampened in the case of the PI controller) around the chosen set point. PMID:26414746

  10. Visual Basic 6.0 Compiles the Control Point Executive Program%用Visual Basic 6.0编写控制点管理程序

    Institute of Scientific and Technical Information of China (English)

    靳周科; 王琛

    2009-01-01

    论述了利用Visual Basic 6.0开发控制点成果管理的计算机应用程序,实现了城市测量控制点成果管理、添加、修改、查询、删除等管理的计算机化,而且查询中成果和点之记直接结合,实现了图、文的对照,使得查询更加科学、便捷.

  11. 3DS Document Reader and Control Based on Visual Basic and OpenGL%基于Visual Basic 2008和OpenGL的3ds

    Institute of Scientific and Technical Information of China (English)

    杨亮; 陈小妹

    2008-01-01

    使用3DS MAX软件进行建模,并将输入文件利用View3ds软件转换成OpenGL格式,数据文件在Visual Basic 2008中进行读取,通过OpenGL对模型进行重构.这种处理方法即能满足快速建模的需要,又能高效的实现友好的交互功能.

  12. Brain-Computer Interfaces for 1-D and 2-D Cursor Control: Designs Using Volitional Control of the EEG Spectrum or Steady-State Visual Evoked Potentials

    Science.gov (United States)

    Trejo, Leonard J.; Matthews, Bryan; Rosipal, Roman

    2005-01-01

    We have developed and tested two EEG-based brain-computer interfaces (BCI) for users to control a cursor on a computer display. Our system uses an adaptive algorithm, based on kernel partial least squares classification (KPLS), to associate patterns in multichannel EEG frequency spectra with cursor controls. Our first BCI, Target Practice, is a system for one-dimensional device control, in which participants use biofeedback to learn voluntary control of their EEG spectra. Target Practice uses a KF LS classifier to map power spectra of 30-electrode EEG signals to rightward or leftward position of a moving cursor on a computer display. Three subjects learned to control motion of a cursor on a video display in multiple blocks of 60 trials over periods of up to six weeks. The best subject s average skill in correct selection of the cursor direction grew from 58% to 88% after 13 training sessions. Target Practice also implements online control of two artifact sources: a) removal of ocular artifact by linear subtraction of wavelet-smoothed vertical and horizontal EOG signals, b) control of muscle artifact by inhibition of BCI training during periods of relatively high power in the 40-64 Hz band. The second BCI, Think Pointer, is a system for two-dimensional cursor control. Steady-state visual evoked potentials (SSVEP) are triggered by four flickering checkerboard stimuli located in narrow strips at each edge of the display. The user attends to one of the four beacons to initiate motion in the desired direction. The SSVEP signals are recorded from eight electrodes located over the occipital region. A KPLS classifier is individually calibrated to map multichannel frequency bands of the SSVEP signals to right-left or up-down motion of a cursor on a computer display. The display stops moving when the user attends to a central fixation point. As for Target Practice, Think Pointer also implements wavelet-based online removal of ocular artifact; however, in Think Pointer muscle

  13. Defects of a mammography quality control phantom visualized by synchrotron radiation imaging

    International Nuclear Information System (INIS)

    Synchrotron radiation (SR) imaging of an RMI 156 mammography quality control phantom, serial number 156-15330, revealed some defects which degraded the visibility of calcification specks. SR imaging was performed at SPring-8, in Harima, Japan by using a monochromatic energy of 20 keV with a field-of-view of 24 X 24 mm. Different kinds of images were obtained by changing sample-to-detector distances; absorption images and refraction-enhanced images. Specks were embedded in a wax matrix and were imaged as black in an absorption image. In a refraction-enhanced image, they were imaged as a black region with white margins. Foreign objects with opposite contrast were detected near, or overlapped with, some specks. As they were depicted as white in the absorption image and as white with a black margin in the refraction-enhanced image, it seemed that they had low X-ray attenuation and a low refraction index compared with the surrounding wax. They might presumable be air bubbles. Visibility of specks in an absorption image was seriously interfered with when those object(s) overlapped with specks. This kind of defect may cause a difficulty in meeting quality assurance specifications when a facility inadvertently purchases defective phantoms. (author)

  14. Cultural adaptation of visual attention: calibration of the oculomotor control system in accordance with cultural scenes.

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Ueda

    Full Text Available Previous studies have found that Westerners are more likely than East Asians to attend to central objects (i.e., analytic attention, whereas East Asians are more likely than Westerners to focus on background objects or context (i.e., holistic attention. Recently, it has been proposed that the physical environment of a given culture influences the cultural form of scene cognition, although the underlying mechanism is yet unclear. This study examined whether the physical environment influences oculomotor control. Participants saw culturally neutral stimuli (e.g., a dog in a park as a baseline, followed by Japanese or United States scenes, and finally culturally neutral stimuli again. The results showed that participants primed with Japanese scenes were more likely to move their eyes within a broader area and they were less likely to fixate on central objects compared with the baseline, whereas there were no significant differences in the eye movements of participants primed with American scenes. These results suggest that culturally specific patterns in eye movements are partly caused by the physical environment.

  15. Collagen attachment to the substrate controls cell clustering through migration

    International Nuclear Information System (INIS)

    Cell clustering and scattering play important roles in cancer progression and tissue engineering. While the extracellular matrix (ECM) is known to control cell clustering, much of the quantitative work has focused on the analysis of clustering between cells with strong cell–cell junctions. Much less is known about how the ECM regulates cells with weak cell–cell contact. Clustering characteristics were quantified in rat adenocarcinoma cells, which form clusters on physically adsorbed collagen substrates, but not on covalently attached collagen substrates. Covalently attaching collagen inhibited desorption of collagen from the surface. While changes in proliferation rate could not explain differences seen in the clustering, changes in cell motility could. Cells plated under conditions that resulted in more clustering had a lower persistence time and slower migration rate than those under conditions that resulted in less clustering. Understanding how the ECM regulates clustering will not only impact the fundamental understanding of cancer progression, but also will guide the design of tissue engineered constructs that allow for the clustering or dissemination of cells throughout the construct. (paper)

  16. Cell cycle control after DNA damage: arrest, recovery and adaptation

    International Nuclear Information System (INIS)

    DNA damage triggers surveillance mechanisms, the DNA checkpoints, that control the genome integrity. The DNA checkpoints induce several responses, either cellular or transcriptional, that favor DNA repair. In particular, activation of the DNA checkpoints inhibits cell cycle progression in all phases, depending on the stage when lesions occur. These arrests are generally transient and cells ultimately reenter the cell division cycle whether lesions have been repaired (this process is termed 'recovery') or have proved un-repairable (this option is called 'adaptation'). The mechanisms controlling cell cycle arrests, recovery and adaptation are largely conserved among eukaryotes, and much information is now available for the yeast Saccharomyces cerevisiae, that is used as a model organism in these studies. (author)

  17. Using VISUAL BASIC to Develop A Process-Control Expert Systen Tool%应用VISUAL BASIC开发过程控制型专家系统工具

    Institute of Scientific and Technical Information of China (English)

    谈龙; 孙鸿宾

    2000-01-01

    To adapt the automation of modern industrial production, this thesis develops aprocess-control expert system tool-the Visual Basic Expert System Tool (abbr. VB-EST) withsimple construction and convenient interface. Developed by the Visual Basic language, the VB-EST consists of three parts: the knowledge base, the inference engine, the trace and help. Withthe VB-EST, the thesis has successfully developed a soaking pits management expert systemwhich process at high speed and achieves good effect.%为适应现代工业生产过程自动化的需要,本文开发了一个结构简单、界面友好、用于过程控制的专家系统工具Visual Basic Expert System Tool(简称:VB-EST)。此工具用Visual Basic语言开发完成,它包括如下三个部分:1.知识库、2.推理机、3.跟踪及帮助。本文已用VB-EST工具成功地开发了均热炉群调度管理专家系统,其速度较高、效果良好。

  18. VISUALIZATION OF LIP AND BASAL-CELL SKIN CANCER IN HIGH-FREQUENCY ELECTRICAL FIELD

    OpenAIRE

    Zabunyan G. A.; Ovsiyenko P. G.

    2015-01-01

    In patients, there has been registered luminescence of skin sites affected by basal cell skin cancer at stage III in high-frequency electric field. The diagnosis was confirmed by histological analysis of excised cancer sites

  19. Fuel cell generator with fuel electrodes that control on-cell fuel reformation

    Science.gov (United States)

    Ruka, Roswell J.; Basel, Richard A.; Zhang, Gong

    2011-10-25

    A fuel cell for a fuel cell generator including a housing including a gas flow path for receiving a fuel from a fuel source and directing the fuel across the fuel cell. The fuel cell includes an elongate member including opposing first and second ends and defining an interior cathode portion and an exterior anode portion. The interior cathode portion includes an electrode in contact with an oxidant flow path. The exterior anode portion includes an electrode in contact with the fuel in the gas flow path. The anode portion includes a catalyst material for effecting fuel reformation along the fuel cell between the opposing ends. A fuel reformation control layer is applied over the catalyst material for reducing a rate of fuel reformation on the fuel cell. The control layer effects a variable reformation rate along the length of the fuel cell.

  20. Control of Th2-Mediated Inflammation by Regulatory T Cells

    OpenAIRE

    Poojary, K. Venuprasad; Kong, Yi-chi M.; Farrar, Michael A.

    2010-01-01

    Allergic diseases and asthma are caused by dysregulated Th2-type immune responses, which drive disease development in susceptible individuals. Immune tolerance to allergens prevents inflammatory symptoms in the respiratory mucosa and provides protection against inflammation in the airways. Increasing evidence indicates that Foxp3+ regulatory T cells (Tregs) play a critical role in immune tolerance and control Th2-biased responses. Tregs develop in the thymus from CD4+ T cells (natural Tregs) ...