64 resultados para 5-DOF haptic interaction


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A series of 5-hydroxy-isoflavones—genistein, biochanin A, prunetin, and 4′,7-dimethoxygenistein—have been studied by surface-enhanced Raman spectroscopy (SERS). Citrate reduced silver colloids were employed as a standard technique to measure SER spectra over a range of pH and concentrations. Density functional theory calculations were used to assist in determining the mode of interaction of isoflavones with the silver nanoparticles. It is revealed that biochanin A and prunetin interact with the silver nanoparticles upon deprotonation of the 7- and the 4′-OH groups, respectively, to show SERS activity. Correlations of their spectra with SERS of genistein strongly support the presence of multiple interaction modes involving both of the OH groups in genistein, in a similar manner to daidzein. Surprisingly, however, under these conditions, the 5-OH group was found to be noninteractive as revealed by attempts to measure SERS of 4′,7-dimethoxygenistein. This was attributed partly to the low solubility and, more importantly, to the influence of steric hindrance, caused by the position of the pendant phenyl ring, which prevented interaction with the Ag colloid surface. These results complement recent work on daidzein and formononetin and provide further insight into understanding the SER spectra of isoflavones.

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To investigate the combined effect of an exon III variable number tandem repeat in the dopamine receptor gene (DRD4) and insecure attachment style on risk for tobacco, cannabis and alcohol use problems in young adulthood. It was hypothesized that (1) individuals with 5, 6, 7 or 8 repeats (labelled 7R+) would be at increased risk for problematic drug use, and (2) risk for drug use would be further increased in individuals with 7R+ repeats who also have a history of insecure parent–child attachment relations. Data were drawn from the Victorian Adolescent Health Cohort Study, an eight-wave longitudinal study of adolescent and young adult development. DRD4 genotypes were available for 839 participants. Risk attributable to the combined effects of 7R+ genotype and insecure attachments was evaluated within a sufficient causes framework under the assumptions of additive interaction using a two-by-four table format with a common reference group. 7R+ alleles were associated with higher tobacco, cannabis and alcohol use (binging). Insecure attachments were associated with higher tobacco and cannabis use but lower alcohol use. For tobacco, there was evidence of interaction for anxious but not avoidant attachments. For cannabis, there was evidence of interaction for both anxious and avoidant attachments, although the interaction for anxious attachments was more substantial. There is no evidence of interaction for binge drinking. Results are consistent with a generic reward deficit hypothesis of drug addiction for which the 7R+ disposition may play a role. Interaction between 7R+ alleles and attachment insecurity may intensify risk for problematic tobacco and cannabis use.

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Utilizing user-centred system design and evaluation method has become an increasingly important tool to foster better usability in the field of virtual environments (VEs). In recent years, although it is still the norm that designers and developers are concerning the technological advancement and striving for designing impressive multimodal multisensory interfaces, more and more awareness are aroused among the development team that in order to produce usable and useful interfaces, it is essential to have users in mind during design and validate a new design from users' perspective. In this paper, we describe a user study carried out to validate a newly developed haptically enabled virtual training system. By taking consideration of the complexity of individual differences on human performance, adoption and acceptance of haptic and audio-visual I/O devices, we address how well users learn, perform, adapt to and perceive object assembly training. We also explore user experience and interaction with the system, and discuss how multisensory feedback affects user performance, perception and acceptance. At last, we discuss how to better design VEs that enhance users perception, their interaction and motor activity.

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Interaction with virtual or teleoperated environments requires contact with objects on a multipoint level. We describe the design of a pinch--grasp hand interface device for use as a grasping mechanism to complement haptic interfaces. To preserve a suitable level of transparency for human--computer interaction, this novel interface is designed for high-resolution contact forces, while centered around a lightweight structure. This functionality renders the device scalable and adaptable to a wide range of haptic interface structures and force level requirements. We present an optimal configuration for a pinch--grasp interface, which produces bidirectional forces to an operator's fingers and a rotational force to the wrist through a cable drive system. The device is characterized for use on a commercial haptic interface through demonstration of sustained peak performance and also workspace utilization. The dynamic performance of the pinch--grasp interface is experimentally determined, and the frequency response is identified to illustrate its contact force resolution.

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Membrane nanotubes (MNTs) are newly discovered cellular extensions that are either blind-ended or can connect widely separated cells. They have predominantly been investigated in cultured isolated cells, however, previously we were the first group to demonstrate the existence of these structures in vivo in intact mammalian tissues. We previously demonstrated the frequency of both cell–cell or bridging MNTs and blind-ended MNTs was greatest between major histocompatibility complex (MHC) class II+ cells during corneal injury or TLR ligand-mediated inflammation. The present study aimed to further explore the dynamics of MNT formation and their size, presence in another tissue, the dura mater, and response to stress factors and an active local viral infection of the murine cornea. Confocal live cell imaging of myeloid-derived cells in inflamed corneal explants from Cx3cr1GFP and CD11ceYFP transgenic mice revealed that MNTs form de novo at a rate of 15.5 μm/min. This observation contrasts with previous studies that demonstrated that in vitro these structures originate from cell–cell contacts. Conditions that promote formation of MNTs include inflammation in vivo and cell stress due to serum starvation ex vivo. Herpes simplex virus-1 infection did not cause a significant increase in MNT numbers in myeloid cells in the cornea above that observed in injury controls, confirming that corneal epithelium injury alone elicits MNT formation in vivo. These novel observations extend the currently limited understanding of MNTs in live mammalian tissues.

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Introduction
The aim of this study was to investigate the change in the relationship between play, language and social skills of children aged 5–8 years pre and post participation in the ‘Learn to Play’ program. The Learn to Play program is a child led play based intervention aimed at developing self-initiated pretend play skills in children.

Methods
All 19 participants attended a specialist school, with 10 of the 19 children having a diagnosis of autism. The play, language and social skills of the children were assessed at baseline and at follow up. Children were assessed using the Child-Initiated Pretend Play Assessment, the Preschool Language Scale and the Penn Interactive Peer Play Scale. Follow up data collection occurred after the children had been participating in the Learn to Play program for 1 hour twice a week for 6 months.

Results
After 6 months in the program, typical indicators of play accounted for an increase of 47.3% in shared variance with social interaction and an increase of 36% in shared variance for social connection. For language, object substitution ability accounted for 50% of the shared variance, which was an increase of 27% from baseline.

Conclusion
The ‘Learn to Play’ program was associated with increases in children's language and social skills over a 6-month period within a special school setting, indicating the Learn to Play program is an effective intervention for children with developmental disabilities. This paper presents an example of how the Learn to Play program can be adapted into a classroom setting.

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Computer haptics has so far been performed on a personal computer (PC). Off the shelf haptic devices provide only PC interfaces and software drivers for control and communication. The new wave of high capable tablet PCs and high end smart phones introduced new platforms for haptic applications. The major problem was to communicate wirelessly to provide user convenience and support mobility which is an essential feature for these platforms. In this paper we provide a wireless layered communication protocol and a hardware setup that enables off the shelf haptic devices to communicate wirelessly with a mobile device. The layers in the protocol enable the change of any hardware components without affecting the data flow. However, the adoption of the wireless interface instead of the wired one comes with the price of speed. Haptic refresh loops require a relatively high refresh rate of 1000 Hz compared to graphics loop which require between 30 and 60 only. An interpolation algorithm was demonstrated to compensate the latency and secure a stable user experience. The introduced setup was tested against portable environments and the users could perform similar functionalities to what are available on a wired setup to a PC.

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Virtual reality and simulation are becoming increasingly important in modern society and it is essential to improve our understanding of system usability and efficacy from the users’ perspective. This paper introduces a novel evaluation method designed to assess human user capability when undertaking technical and procedural training using virtual training systems. The evaluation method falls under the user-centred design and evaluation paradigm and draws on theories of cognitive, skillbased and affective learning outcomes. The method focuses on user interaction with haptic-audio-visual interfaces and the complexities related to variability in users’ performance, and the adoption and acceptance of the technologies. A large scale user study focusing on object assembly training tasks involving selecting, rotating, releasing, inserting and manipulating 3D objects was performed. The study demonstrated the advantages of the method in obtaining valuable multimodal information for accurate and comprehensive evaluation of virtual training system efficacy. The study investigated how well users learn, perform, adapt to and perceive the virtual training. The results of the study revealed valuable aspects of the design and evaluation of virtual training systems contributing to an improved understanding of more usable virtual training systems.

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Background: Debate is ongoing about what role, if any, variation in the serotonin transporter linked polymorphic region (5-HTTLPR) plays in depression. Some studies report an interaction between 5-HTTLPR variation and stressful life events affecting the risk for depression, others report a main effect of 5-HTTLPR variation on depression, while others find no evidence for either a main or interaction effect. Meta-analyses of multiple studies have also reached differing conclusions.

Methods/Design:
To improve understanding of the combined roles of 5-HTTLPR variation and stress in the development of depression, we are conducting a meta-analysis of multiple independent datasets. This coordinated approach utilizes new analyses performed with centrally-developed, standardized scripts. This publication documents the protocol for this collaborative, consortium-based meta-analysis of 5-HTTLPR variation, stress, and depression.

Study eligibility criteria: Our goal is to invite all datasets, published or unpublished, with 5-HTTLPR genotype and assessments of stress and depression for at least 300 subjects. This inclusive approach is to minimize potential impact from publication bias.

Data sources: This project currently includes investigators from 35 independent groups, providing data on at least N = 33,761 participants.  The analytic plan was determined prior to starting data analysis. Analyses of individual study datasets will be performed by the investigators who collected the data using centrally-developed standardized analysis scripts to ensure a consistent analytical approach across sites. The consortium as a group will review and interpret the meta-analysis results.

Discussion:
Variation in 5-HTTLPR is hypothesized to moderate the response to stress on depression. To test specific hypotheses about the role of 5-HTTLPR variation on depression, we will perform coordinated meta-analyses of de novo results obtained from all available data, using variables and analyses determined a priori. Primary analyses, based on the original 2003 report by Caspi and colleagues of a GxE interaction will be supplemented by secondary analyses to help interpret and clarify issues ranging from the mechanism of effect to heterogeneity among the contributing studies. Publication of this protocol serves to protect this project from biased reporting and to improve the ability of readers to interpret the results of this specific meta-analysis upon its completion.

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The present invention provides remote interfacing utilising haptic technology. In a first aspect there is provided a haptic grasping interface comprising a plurality of finger interaction points, with actuators connected at one end to an actuator control mechanism. The mechanism is mounted remotely from the grasping interface, inverse to the finger interaction points, for manipulation of these points. The grasping points comprise pulleys which route the actuators through a cable tension and transmission system. A second aspect provides haptic augmentation to an operator, which indicates to the operator the state of a control input to a controlled device. A third aspect provides a means of simulating motion where haptic feedback is provided to a user in correspondence with the movement of the user within a pod environment.

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The present invention provides remote interfacing utilising haptic technology. In a first aspect there is provided a haptic grasping interface comprising a plurality of finger interaction points, with actuators connected at one end to an actuator control mechanism. The mechanism is mounted remotely from the grasping interface, inverse to the finger interaction points, for manipulation of these points. The grasping points comprise pulleys which route the actuators through a cable tension and transmission system. A second aspect provides haptic augmentation to an operator, which indicates to the operator the state of a control input to a controlled device. A third aspect provides a means of simulating motion where haptic feedback is provided to a user in correspondence with the movement of the user within a pod environment.

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 Determining an analytical solution to the inverse kinematics problem for a parallel manipulator is typically a straightforward problem. However, lower mobility parallel manipulators with 2-5 degrees of freedom (DOFs) often suffer from an unwanted parasitic motion in one or more DOFs. For such manipulators, the inverse kinematics problem can be significantly more difficult. This paper contains an analysis of the inverse kinematics problem for a class of 3-DOF parallel manipulators with axis-symmetric arm systems. All manipulators in the studied class exhibit parasitic motion in one DOF. For manipulators in the studied class, the general solution to the inverse kinematics problem is reduced to solving a univariate equation, while analytical solutions are presented for several important special cases.

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Five types of Mg-5Al alloys with different weight percentages of Zn ranging from 0 to 4 wt.% were examined using electrochemical techniques and surface analysis. The electrochemical results indicated that the Mg-5Al alloys containing Zn have a lower corrosion and hydrogen evolution rates than the Mg-5Al based specimens with a decrease of value being observed with the decrease in Zn content. Zn addition induced the precipitation of Mg-Al and Mg-Zn phases in the Mg matrix along with grain refinement and increased an interaction of Zn oxide with Mg and Al products serving as a corrosion barrier. © 2014 Elsevier B.V. All rights reserved.