324 research outputs found

    Almost automorphic delayed differential equations and Lasota-Wazewska model

    Full text link
    Existence of almost automorphic solutions for abstract delayed differential equations is established. Using ergodicity, exponential dichotomy and Bi-almost automorphicity on the homogeneous part, sufficient conditions for the existence and uniqueness of almost automorphic solutions are given.Comment: 16 page

    Natural Orifice Transesophageal Endoscopic Surgery: State of the Art

    Get PDF
    The main goal of Natural Orifice Transluminal Endoscopic Surgery (NOTES) is performing surgery avoiding skin incisions. Theoretical advantages of NOTES include decreased postoperative pain, reduction/elimination of general anesthesia, improved cosmetic outcomes, elimination of skin incision-related complications such as wound infections and hernias, and increased overall patient satisfaction. Although various forms of port creation to accomplish thoracic NOTES procedures have been proposed, transesophageal NOTES has been shown to be the most reliable one. The evolution of endoscopic submucosal transesophageal access resulted in the development of per-oral endoscopic myotomy (POEM), which had a fast transition to clinical practice. The authors present a review of the current state of the art concerning transesophageal NOTES, looking at its potential for diagnostic and therapeutic interventions as well as the hurdles yet to be overcome

    Transesophageal pulmonary lobectomy with single transthoracic port assistance: study with survival assessment in a porcine model

    Get PDF
    BACKGROUND AND STUDY AIMS: Thoracoscopic pulmonary lobectomy is being performed in an increasing number of patients. The aims of the current study were to assess natural orifice transluminal endoscopic surgery (NOTES) as an alternative to transthoracic endoscopic surgery, and to test the feasibility of peroral transesophageal right upper pulmonary lobectomy with the assistance of a single transthoracic trocar. METHODS: In 10 acute and 4 survival pigs, right upper pulmonary lobectomy was performed using a forward-viewing double-channel gastroscope and an operative thoracoscope with a 5-mm working channel inserted through a single transthoracic 12-mm) port. Time, safety, and feasibility of the following steps were recorded in all animals: esophagotomy, hilar dissection, individual ligation of the hilum elements, pulmonary lobectomy, and specimen retrieval. In the survival experiments, esophagotomy was closed using a reticulated laparoscopy suture device and an esophageal stent was placed. These animals were kept alive and monitored for 2 weeks. RESULTS: Esophagotomy was performed safely in all animals (mean procedure duration 5.4 ± 1.7 minutes). Dissection of the right upper lobe hilum elements (bronchus, arteries, and veins) was carried out without adverse events. Individual ligation of the hilum elements was performed in all but two cases (time for dissection and ligation 44.2 ± 14.8 minutes). Lobectomy and specimen retrieval were completed in all animals (9.5 ± 3.1 minutes). Esophagotomy closure and stent placement were carried out in 20.0 ± 2.8 minutes in the survival animals. These animals fed normally and gained weight postoperatively without signs of disease. Endoscopic examination before necropsy revealed a pseudo-diverticulum in one animal, and wound dehiscence with confined collection/recess in the remaining animals. CONCLUSIONS: Transesophageal right upper pulmonary lobectomy using single transthoracic trocar assistance is feasible and may represent a step towards scar-free pulmonary lobectomy.This project was funded by the FCT Grants project PTDC/SAUOSM/105578/2008

    Left atrial appendage ligation with single transthoracic port assistance : a study of survival assessment in a porcine model (with videos)

    Get PDF
    Background: Left atrial appendage (LAA) exclusion is a well-known procedure for the prevention of stroke in high-risk patients with atrial fibrillation and contraindication to long-term oral anticoagulant therapy. Objective: To evaluate a natural orifice transluminal endoscopic surgery (NOTES) approach for LAA ligation. Design: In 4 acute and 6 survival pigs, we performed LAA by using a forward-viewing, single-channelgastroscope and an operative thoracoscope with a 3-mm working channel (introduced through an 8-mm single transthoracic port). Setting: Animal laboratory. Interventions: The gastroscope was introduced in the thoracic cavity through an esophageal submucosal tunnel. An end loop introduced through the gastroscope was used to legate the LAA. In the survival experiments, the esophageal mucosa was closed using hemoclips. Main Outcome Measurements: The time, safety, and feasibility of the procedure were recorded. In the survival experiments, endoscopy and postmortem examination were performed on postoperative day 14. Results: Creation of a submucosal tunnel and esophagotomy were safely performed in all animals without incidents. The mean time for esophagotomy was 17.0 6.3 minutes. Pericardial dissection and LAA ligation were performed in all animals but 1. The mean time for LAA ligation was 34.4 19.1 minutes. No adverse events occurred during the survival period. Endoscopy showed complete esophageal closure. Postmortem examination revealed pleural adhesions on the site of pericardial dissection, and the LAA was fibrotic with the endoloop in place. Limitations: Animal study. Conclusions: LAA ligation with single transthoracic trocar assistance is feasible and may be an alternative to anticoagulant therapy or to permanent intracardiac implants in patients with atrial fibrillation.This project was funded by the Grants FCT project PTDC/SAU-OSM/105578/2008

    O princípio da proporcionalidade na jurisprudência do Supremo Tribunal Federal

    Get PDF
    Este trabalho discute o princípio da proporcionalidade na jurisprudência do Supremo Tribunal Federal. Fez-se uma breve incursão nos elementos, fundamentos e conceitos básicos do princípio da proporcionalidade. Com o intuito de tornar o trabalho autocontido, procedeu-se a um exame de precedentes colhidos da jurisprudência do STF. Detalhou-se a legitimidade do princípio como metodologia hermenêutica aplicável na jurisdição constitucional e, em especial, no controle de constitucionalidade das leis, sob a perspectiva dos alicerces do Estado democrático de direito.This work overviews the Principle of Proportionality from the Supreme Courts jurisprudence. The elements, fundaments and basic concepts of the Principle of Proportionality have been introduced. With the intention of making the work self-contained, a collection of precedents from the Supreme Court has been examined. The legitimacy of the principle as hermeneutic methodology applicable in the constitutional jurisdiction, specifically in the constitutionality control of the laws, has been outlined based upon the Democratic State of Law

    eABC: scientific publications bibliografic archive

    Get PDF
    The paper intends to present eABC – Scientific Publications Bibliographic Archive of University of Aveiro’. It describes the motivation that induced its implementation, advantages for users and for all those whom the system serves. Some of the systems functionalities will be presented, along with a description on how to use them. Finally, the current status of the system - as it is being used by the University of Aveiro - will be presented, with the addition of an explanation on how this system helps in the creation of mechanisms that enable the adaptability and flexibility of systems to improve the scientific community dynamics

    Inhibitory autapse mediates anticipated synchronization between coupled neurons

    Get PDF
    Two identical autonomous dynamical systems unidirectionally coupled in a sender-receiver configuration can exhibit anticipated synchronization (AS) if the Receiver neuron (R) also receives a delayed negative self-feedback. Recently, AS was shown to occur in a three-neuron motif with standard chemical synapses where the delayed inhibition was provided by an interneuron. Here we show that a two-neuron model in the presence of an inhibitory autapse, which is a massive self-innervation present in the cortical architecture, may present AS. The GABAergic autapse regulates the internal dynamics of the Receiver neuron and acts as the negative delayed self-feedback required by dynamical systems in order to exhibit AS. In this biologically plausible scenario, a smooth transition from the usual delayed synchronization (DS) to AS typically occurs when the inhibitory conductance is increased. The phenomenon is shown to be robust when model parameters are varied within a physiological range. For extremely large values of the inhibitory autapse the system undergoes to a phase-drift regime in which the Receiver is faster than the Sender. Furthermore, we show that the inhibitory autapse promotes a faster internal dynamics of the free-running Receiver when the two neurons are uncoupled, which could be the mechanism underlying anticipated synchronization and the DS-AS transition.Fil: Pinto, Marcel A.. Universidade Federal de Alagoas; BrasilFil: Rosso, Osvaldo Aníbal. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Hospital Italiano. Departamento de Informática En Salud.; Argentina. Universidade Federal de Alagoas; Brasil. Universidad de Los Andes. Facultad de Medicina.; ChileFil: Matias, Fernanda S.. Universidade Federal de Alagoas; Brasi
    corecore