Study of the interaction of mononuclear and polynuclear vanadium(V) species with DNA and their possible application as antitumor agents

[Resumo}: Este Traballo de Fin de Grao recolle o estudo de distintos compostos de vanadio (V), tanto mononucleares como polinucleares, a súa interacción co ADN e a posibilidade de que sexan aplicados como axentes antitumorais. O traballo estrutúrase en tres partes. A primeira correspóndese coa síntese e caracterización dos distintos compostos de vanadio: unha especie mononuclear, unha trinuclear e outra decanuclear; así como dun ligando orgánico que constitúe o complexo mononuclear. A análise estrutural lévase a cabo mediante técnicas en estado sólido, espectroscopia de IR e difracción de raios X de monocristal, e en disolución, espectrometría de masas e espectroscopia de RMN 1H. A segunda parte está constituída por un estudo in vitro, onde se determinará a citotoxicidade de dous dos compostos (o ligando e a especie trinuclear), determinando a viabilidade celular mediante unha técnica colorimétrica. Finalmente, a última parte consta dun estudo computacional, empregando a técnica de molecular docking, da interacción dos compostos co ADN, sabendo que esta é a principal diana terapéutica na busca da cura contra o cancro.[Resumen]: Este Trabajo de Fin de Grado recoge el estudio de distintos compuestos de vanadio (V), tanto mononucleares como polinucleares, su interacción con el ADN y la posibilidad de que sean aplicados como agentes antitumorales. El trabajo se estructura en tres partes. La primera se corresponde con la síntesis y caracterización de los distintos compuestos de vanadio: una especie mononuclear, una trinuclear y otra decanuclear; así como de un ligando orgánico que constituye el complejo mononuclear. El análisis estructural se lleva a cabo mediante técnicas en estado sólido, espectroscopia de IR y difracción de rayos X de monocristal, y en disolución, espectrometría de masas y espectroscopia de RMN 1H. La segunda parte está constituida por un estudio in vitro, donde se determinará la citotoxicidad de dos de los compuestos (el ligando y la especie trinuclear), determinando la viabilidad celular mediante una técnica colorimétrica. Finalmente, la última parte consta de un estudio computacional, empleando la técnica de molecular docking, de la interacción de los compuestos con el ADN, sabiendo que esta es la principal diana terapéutica en la búsqueda de la cura contra el cáncer.[Abstrac]: This End-of-Degree Project is a study of different vanadium(V) compounds, mononuclear and polynuclear, their interaction with DNA and their possible application as antitumor agents. The project consists of three parts. The first one is the synthesis and characterization of the different vanadium compounds: a mononuclear specie, a trinuclear specie and a decanuclear one; as well as of an organic ligand that constitutes the mononuclear complex. The structural analysis is carried out by solid state techniques, IR spectroscopy and X-ray diffraction, and in dissolution, mass spectrometry and RMN 1H spectroscopy. The second part is an in vitro study where will be determinate the cytotoxicity of two compounds, the ligand and the trinuclear specie, determining the cellular viability by a colorimetric technique. Finally, the last part is a computational study by molecular docking about compound´s interaction with DNA, the main therapeutic target in the search for a cure against cancer.Traballo fin de grao (UDC.CIE). Química. Curso 2017/201

Reliable robotic handovers through tactile sensing

Joint manipulation and object exchange are common in many everyday scenarios. Although they are trivial tasks for humans, they are still very challenging for robots. Existing approaches for robot-to-human object handover assume that there is no fault during the transfer. However, unintentional perturbation forces can be occasionally applied to the object, resulting in the robot and the object being damaged, for example by being dropped. In this paper we present a novel approach to handover objects in a reliable manner while ensuring the safety of the robot and the object. Relying on tactile sensing, the system uses an effort controller to adapt the grasp forces in the presence of perturbations. Moreover, the proposed approach identifies a perturbation being applied on the object. When a perturbation event is detected, the algorithm classifies the direction of the pulling forces to decide whether to release it or not. The reliable handover system was implemented using a Shadow Robot hand equipped with BioTAC tactile sensors. Our results show that the system correctly adapts to the forces applied on the object to maintain the grasp and only releases the object if the human receiver pulls in the right direction

Using Reinforcement Learning to Attenuate for Stochasticity in Robot Navigation Controllers

International audienceBraitenberg vehicles are bio-inspired controllers for sensor-based local navigation of wheeled robots that have been used in multiple real world robotic implementations. The common approach to implement such non-linear control mechanisms is through neural networks connecting sensing to motor action, yet tuning the weights to obtain appropriate closed-loop navigation behaviours can be very challenging. Standard approaches used hand tuned spiking or recurrent neural networks, or learnt the weights of feedforward networks using evolutionary approaches. Recently, Reinforcement Learning has been used to learn neural controllers for simulated Braitenberg vehicle 3a-a bio-inspired model of target seeking for wheeled robots-under the assumption of noiseless sensors. Real sensors, however, are subject to different levels of noise, and multiple works have shown that Braitenberg vehicles work even on outdoor robots, demonstrating that these control mechanisms work in harsh and dynamic environments. This paper shows that a robust neural controller for Braitenberg vehicle 3a can be learnt using policy gradient reinforcement learning in scenarios where sensor noise plays a non negligible role. The learnt controller is robust and tries to attenuate the effects of noise in the closed-loop navigation behaviour of the simulated stochastic vehicle. We compare the neural controller learnt using Reinforcement Learning with a simple hand tuned controller and show how the neural control mechanism outperforms a naïve controller. Results are illustrated through computer simulations of the closed-loop stochastic system

Adaptive reinforcement learning with active state-specific exploration for engagement maximization during simulated child-robot interaction

International audienceUsing assistive robots for educational applications requires robots to be able to adapt their behavior specifically for each child with whom they interact. Among relevant signals, non-verbal cues such as the child's gaze can provide the robot with important information about the child's current engagement in the task, and whether the robot should continue its current behavior or not. Here we propose a reinforcement learning algorithm extended with active state-specific exploration and show its applicability to child engagement maximization as well as more classical tasks such as maze navigation. We first demonstrate its adaptive nature on a continuous maze problem as an enhancement of the classic grid world. There, parame-terized actions enable the agent to learn single moves until the end of a corridor, similarly to "options" but without explicit hierarchical representations. We then apply the algorithm to a series of simulated scenarios, such as an extended Tower of Hanoi where the robot should find the appropriate speed of movement for the interacting child, and to a pointing task where the robot should find the child-specific appropriate level of expressivity of action. We show that the algorithm enables to cope with both global and local non-stationarities in the state space while preserving a stable behavior in other stationary portions of the state space. Altogether, these results suggest a promising way to enable robot learning based on non-verbal cues and the high degree of non-stationarities that can occur during interaction with children

Study of vanadium (IV and V) complexes with hydrazone ligands derived from pyridoxal and their possible applications as antitumor agents

[Resumo]: Este Traballo de Fin de Máster recolle os primeiros pasos dunha investigación na procura de novos axentes antitumorais baseados en complexos de vanadio con ligandos hidrazona. Na primeira parte do traballo móstrase a ruta sintética levada a cabo para a obtención dos ligandos e dos complexos de vanadio (IV e V), así como a caracterización de todos os produtos obtidos. Este estudo realízase aplicando técnicas de caracterización tanto en estado sólido – espectroscopia de IR, análise elemental e difracción de raios X de monocristal –, como en disolución – espectrometría de masas e espectroscopia de RMN 1H. A segunda parte recolle un estudo in vitro para a determinación da citotoxicidade de tres dos complexos sintetizados e o estudo mediante espectroscopia UV-vis da interacción destes mesmos complexos co ADN. Inclúese ademais o cálculo da interacción co ADN máis probable para algún dos compostos, empregando a técnica de molecular docking.[Abstract]: This end-of-Master´s project contains the first steps of an investigation on finding new antitumoral agents based on vanadium complexes with hidrazone ligands. The first part of the project shows the synthetic route carried out for the obtention of the ligands and the vanadium (IV and V) complexes, just as the characterization of the products obtained. This study was carried out by the application of characterization techniques, both in solid state – IR spectroscopy, elemental analysis and X-RAY monocrystal diffraction –, and in solution – mass spectrometry and RMN 1H spectroscopy. The second part presents an in-vitro study to determinate the cytotoxicity of three of the synthesized complexes and the UV-vis spectroscopy study of that complexes' interaction with DNA. The calculation of the most probable interaction for some of the compounds with DNA applying the molecular docking technique is also included.Traballo fin de mestrado (UDC.CIE). Investigación química y química industrial. Curso 2018/201

Multimodal material identification through recursive tactile sensing

Tactile sensing has recently been used in robotics for object identification, grasping, and material identification. Although human tactile sensing is multimodal, existing material recognition approaches use vibration information only. Moreover, material identification through tactile sensing can be solved as an continuous process, yet state of the art approaches use a batch approach where readings are taken for at least one second. This work proposes a recursive multimodal (vibration and thermal) tactile material identification approach. Using the frequency response of the vibration induced by the material and a set of thermal features, we show that it is possible to accurately identify materials in less than half a second. We conducted an exhaustive comparison of our approach with commonly used vibration descriptors and machine learning algorithms for material identification such as k-Nearest Neighbour, Artificial Neural Network and Support Vector Machines. Experimental results show that our approach identifies materials faster than existing techniques and increase the classification accuracy when multiple sensor modalities are used

En el Real Club de Regatas Galicia

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201