265 research outputs found
Redundancy Optimization Strategy for Hands-On Robotic Surgery
During hands-on cooperative surgery, the use of a redundant robot allows to address encumbrance issues in the Operating Room (OR), which can occur due to the presence of large medical instrumentation, such as the surgical microscope. This work presents a new Null Space Optimization (NSO) strategy to constraint the position of the manipulator’s elbow within predefined range of motions, according to the spatial requirements of the specific procedure, also taking into account the physical joint limits of the robotic assistant. The proposed strategy was applied to the 7 degrees of freedom (dof) lightweight robot LWR4+. The performance of the NSO was compared to two state-of-the-art null space optimization strategies, i.e. damped posture and fixed optimal posture, over a pool of three non-expert users in both strict (20deg) and negligible (100deg) angular encumbrance limitations. The NSO strategy was proved versatile in providing wide elbow mobility together with safe distance from relevant continuity null space boundaries, guaranteeing smooth guidance trajectories. Future works would be performed in order to evaluate the potential feasibility of NSO in a real surgical scenario
Gesteme-free context-aware adaptation of robot behavior in human–robot cooperation
Background: Cooperative robotics is receiving greater acceptance because the typical advantages provided by manipulators are combined with an intuitive usage. In particular, hands-on robotics may benefit from the adaptation of the assistant behavior with respect to the activity currently performed by the user. A fast and reliable classification of human activities is required, as well as strategies to smoothly modify the control of the manipulator. In this scenario, gesteme-based motion classification is inadequate because it needs the observation of a wide signal percentage and the definition of a rich vocabulary.
Objective: In this work, a system able to recognize the user's current activity without a vocabulary of gestemes, and to accordingly adapt the manipulator's dynamic behavior is presented.
Methods and material: An underlying stochastic model fits variations in the user's guidance forces and the resulting trajectories of the manipulator's end-effector with a set of Gaussian distribution. The high-level switching between these distributions is captured with hidden Markov models. The dynamic of the KUKA light-weight robot, a torque-controlled manipulator, is modified with respect to the classified activity using sigmoidal-shaped functions. The presented system is validated over a pool of 12 naive users in a scenario that addresses surgical targeting tasks on soft tissue. The robot's assistance is adapted in order to obtain a stiff behavior during activities that require critical accuracy constraint, and higher compliance during wide movements. Both the ability to provide the correct classification at each moment (sample accuracy) and the capability of correctly identify the correct sequence of activity (sequence accuracy) were evaluated.
Results: The proposed classifier is fast and accurate in all the experiments conducted (80% sample accuracy after the observation of similar to 450 ms of signal). Moreover, the ability of recognize the correct sequence of activities, without unwanted transitions is guaranteed (sequence accuracy similar to 90% when computed far away from user desired transitions). Finally, the proposed activity-based adaptation of the robot's dynamic does not lead to a not smooth behavior (high smoothness, i.e. normalized jerk score <0.01).
Conclusion: The provided system is able to dynamic assist the operator during cooperation in the presented scenario
Experimental and simulated displacement in cracked specimen of P91 steel under creep conditions
Heterologous microarray experiments allow the identification of the early events associated with potato tuber cold sweetening
<p>Abstract</p> <p>Background</p> <p>Since its discovery more than 100 years ago, potato (<it>Solanum tuberosum</it>) tuber cold-induced sweetening (CIS) has been extensively investigated. Several carbohydrate-associated genes would seem to be involved in the process. However, many uncertainties still exist, as the relative contribution of each gene to the process is often unclear, possibly as the consequence of the heterogeneity of experimental systems. Some enzymes associated with CIS, such as β-amylases and invertases, have still to be identified at a sequence level. In addition, little is known about the early events that trigger CIS and on the involvement/association with CIS of genes different from carbohydrate-associated genes. Many of these uncertainties could be resolved by profiling experiments, but no GeneChip is available for the potato, and the production of the potato cDNA spotted array (TIGR) has recently been discontinued. In order to obtain an overall picture of early transcriptional events associated with CIS, we investigated whether the commercially-available tomato Affymetrix GeneChip could be used to identify which potato cold-responsive gene family members should be further studied in detail by Real-Time (RT)-PCR (qPCR).</p> <p>Results</p> <p>A tomato-potato Global Match File was generated for the interpretation of various aspects of the heterologous dataset, including the retrieval of best matching potato counterparts and annotation, and the establishment of a core set of highly homologous genes. Several cold-responsive genes were identified, and their expression pattern was studied in detail by qPCR over 26 days. We detected biphasic behaviour of mRNA accumulation for carbohydrate-associated genes and our combined GeneChip-qPCR data identified, at a sequence level, enzymatic activities such as β-amylases and invertases previously reported as being involved in CIS. The GeneChip data also unveiled important processes accompanying CIS, such as the induction of redox- and ethylene-associated genes.</p> <p>Conclusion</p> <p>Our Global Match File strategy proved critical for accurately interpretating heterologous datasets, and suggests that similar approaches may be fruitful for other species. Transcript profiling of early events associated with CIS revealed a complex network of events involving sugars, redox and hormone signalling which may be either linked serially or act in parallel. The identification, at a sequence level, of various enzymes long known as having a role in CIS provides molecular tools for further understanding the phenomenon.</p
A Roadmap for Molecular Field-Coupled Nanocomputing Actualization
In molecular field-coupled nanocomputing, electrostatically-coupled molecules encode the logic information in their charge distribution, promising extremely low power consumption, room temperature operation, and THz frequency operations. Besides the impressive theoretical predictions and simulation confirmations, a working prototype must still be fabricated. This work discusses the most crucial aspects that hinder the fabrication of a working prototype and defines a roadmap to address and guide the procedure to fabricate a working proof of concept. Accurate physical simulations support each point of the roadmap
Construcciones identitarias en tiempos de Facebook: el caso Indignados Córdoba
Trabajo Final de Licenciatura en Comunicación Social de la Universidad Nacional de Córdoba, dirigido por María Belén Espoz Dalmasso. Aprobado el 7 de mayo de 2018, con calificación 8 (ocho).Ante la crisis político económica europea de 2011, en España surge un movimiento conocido como “Indignados” que inicia una serie de protestas contra el gobierno y llama a los ciudadanos de todo el mundo a unirse para alcanzar un levantamiento de escala global. Tiene una incidencia crucial en todo este proceso el avance en las tecnologías de la información y la comunicación con una amplia disponibilidad de dispositivos móviles y el uso masivo de las redes sociales que facilitaron una rápida propagación de las ideas y un alcance masivo sorteando barreras territoriales. En ese contexto, en la ciudad de Córdoba surge el grupo “Indignados Córdoba” con la intención de sumarse a los reclamos globales y visibilizar problemáticas locales utilizando Facebook como herramienta para la coordinación de sus acciones y comunicaciones. Este trabajo busca analizar las dinámicas comunicacionales del grupo en el espacio de la red social e indagar sobre los procesos de construcción identitaria en los espacios virtuales reconociendo sus particularidades además de las dificultades que supone atravesar ese proceso. Si bien las redes sociales, desde una primera mirada, pareciera que vinieran a facilitar los canales de interacción, la configuración de las relaciones que en ella se desarrollan requieren de un análisis atento para comprender las problemáticas que atraviesan los procesos identitarios en estos días en los que la socialización también transcurre en ámbitos virtuales
Construcciones identitarias en tiempos de Facebook: el caso Indignados Córdoba
Trabajo Final de Licenciatura en Comunicación Social de la Universidad Nacional de Córdoba, dirigido por María Belén Espoz Dalmasso. Aprobado el 7 de mayo de 2018, con calificación 8 (ocho).Ante la crisis político económica europea de 2011, en España surge un movimiento conocido como “Indignados” que inicia una serie de protestas contra el gobierno y llama a los ciudadanos de todo el mundo a unirse para alcanzar un levantamiento de escala global. Tiene una incidencia crucial en todo este proceso el avance en las tecnologías de la información y la comunicación con una amplia disponibilidad de dispositivos móviles y el uso masivo de las redes sociales que facilitaron una rápida propagación de las ideas y un alcance masivo sorteando barreras territoriales. En ese contexto, en la ciudad de Córdoba surge el grupo “Indignados Córdoba” con la intención de sumarse a los reclamos globales y visibilizar problemáticas locales utilizando Facebook como herramienta para la coordinación de sus acciones y comunicaciones. Este trabajo busca analizar las dinámicas comunicacionales del grupo en el espacio de la red social e indagar sobre los procesos de construcción identitaria en los espacios virtuales reconociendo sus particularidades además de las dificultades que supone atravesar ese proceso. Si bien las redes sociales, desde una primera mirada, pareciera que vinieran a facilitar los canales de interacción, la configuración de las relaciones que en ella se desarrollan requieren de un análisis atento para comprender las problemáticas que atraviesan los procesos identitarios en estos días en los que la socialización también transcurre en ámbitos virtuales
Relationships between bioactive compound content and the antiplatelet and antioxidant activities of six allium vegetable species
Allium sp. vegetables are widely consumed for their characteristic flavour. Additionally, their consumption may provide protection against cardiovascular disease due to their antiplatelet and antioxidant activities. Although antiplatelet and antioxidant activities in Allium sp. are generally recognised, comparative studies of antiplatelet and antioxidant potency among the main Allium vegetable species are lacking. Also, the relationship between organosulfur and phenolic compounds and these biological activities has not been well established.
In this study, the in vitro antiplatelet and antioxidant activities of the most widely
consumed Allium species are characterised and compared. The species total organosulfur and phenolic content, and the HPLC profiles of 11 phenolic compounds were characterised and used to investigate the relationship between these compounds and antiplatelet and antioxidant activities. Furthermore, antiplatelet activities in chives and shallot have been characterised for the first time. Our results revealed that the strongest antiplatelet agents were garlic and shallot, whereas chives had the highest antioxidant activity. Leek and bunching
onion had the weakest both biological activities. Significantly positive correlations were found between the in vitro antiplatelet activity and total organosulfur (R=0.74) and phenolic (TP) content (R=0.73), as well as between the antioxidant activity and TP (R=0.91) and total organosulfur content (R=0.67). Six individual phenolic compounds were associated with the antioxidant activity, with catechin, epigallocatechin and epicatechin gallate having the strongest correlation values (R>0.80). Overall, our results suggest that both organosulfur and phenolic
compounds contribute similarly to Allium antiplatelet activity, whereas phenolics, as a whole, are largely responsible for antioxidant activity, with broad variation observed among the contributions of individual phenolic compounds.Inst. de BiotecnologíaFil: Beretta, Hebe Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Bannoud, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Insani, Ester MarinaI. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; ArgentinaFil: Berli, Federico Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Hirschegger, Pablo. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Galmarini, Claudio Romulo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Consulta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; ArgentinaFil: Cavagnaro, Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria La Consulta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias; Argentin
amda 2 13 a major update for automated cross platform microarray data analysis
Microarray platforms require analytical pipelines with modules for data pre-processing including data normalization, statistical analysis for identification of differentially expressed genes, cluster analysis, and functional annotation. We previously developed the Automated Microarray Data Analysis (AMDA, version 2.3.5) pipeline to process Affymetrix 3′ IVT GeneChips. The availability of newer technologies that demand open-source tools for microarray data analysis has impelled us to develop an updated multi-platform version, AMDA 2.13. It includes additional quality control metrics, annotation-driven (annotation grade of Affymetrix NetAffx) and signal-driven (Inter-Quartile Range) gene filtering, and approaches to experimental design. To enhance understanding of biological data, differentially expressed genes have been mapped into KEGG pathways. Finally, a more stable and user-friendly interface was designed to integrate the requirements for different platforms. AMDA 2.13 allows the analysis of Affymetrix..
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