426 research outputs found

    Hybrid debranching and TEVAR of the aortic arch off-pump, in re-do patients with complicated chronic type-A aortic dissections : a critical report

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    Background: Patients suffering from acute type A aortic dissection undergo replacement of the ascending aorta, the proximal hemiarch or complete aortic arch, depending on the extent of the individual pathology. In a subset of these treated patients, secondary pathologies of the distal anastomosis or the remaining distal part of the aorta occur. The treatment of these pathologies is challenging, requiring major surgical re-do procedures with aortic arch replacement under extracorporeal circulation and hypothermic circulatory arrest. Methods: We report our experience of five patients with complex aortic pathologies after previous aortic surgery treated with a single stage re-do hybrid procedure, consisting of bypass grafting of the supraaortic branches off-pump, stent graft placement for endovascular aortic repair (TEVAR) and surgical debranching of the aortic arch. Results: In all patients the surgical vascular grafts and stent grafts were deployed successfully, there were no intraoperative deaths. Four out of five patients were discharged from hospital in good clinical condition. One patient died postoperatively due to cardiac tamponade. In one patient a type I endoleak persisted leading to occlusion of a bypass branch requiring surgical revision at one year after debranching. Conclusion: We discuss the prerequisites, all steps and potential pitfalls of this hybrid aortic arch replacement. The current procedure avoids cardiopulmonary bypass and circulatory arrest, which may benefit early patient outcome; however, patient and device selection plays a key role for immediate success and midterm outcomes. In addition, precise procedural planning and development of customized stents may help to develop this procedure into a true alternative for conventional aortic arch replacement

    Características y propiedades de los ignimbritos de Bitlis y sus implicaciones ambientales

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    Bitlis rock is used as a construction material and comes from the lava emitted by volcanoes and their subsequent transformation into ignimbrites. This type of rocks has been characterized physically, chemi­cally, toxicologically and radioactively using different procedures including determination of the coefficient of thermal conductivity, gamma spectrometry, ultrasonic speed test, ICP masses and metal extraction. The results indicate that Bitlis rocks have an ACI greater than 1, although their content of radon is lower than other rocks of volcanic origin. Leaching of metals from these rocks indicates that Pb and Cd can provide an infiltration level in the field higher than the level permitted by TCLP and they have undesired toxicological risks. The percent­ages of extraction of other metals also point to this infiltration problem. Despite this, the material offers good qualities for usage as a building material such as its thermal coefficients.La roca Bitlis se utiliza como material de construcción y proviene de la lava emitida por los volcanes y su posterior transformación en ignimbritas. Este tipo de rocas se ha caracterizado física, química, toxicológica y radioactivamente utilizando diferentes procedimientos, incluida la determinación del coeficiente de conductividad térmica, espectrometría gamma, prueba de velocidad ultrasónica, ICP masas y extracción de metales. Los resultados indican que las rocas Bitlis tienen un ACI mayor que 1, aunque su contenido de radón es más bajo que el de otras rocas de origen volcánico. La lixiviación de metales de estas rocas indica que el Pb y el Cd pueden proporcionar un nivel de infiltración en el campo más alto que el nivel permitido por TCLP y tener riesgos toxicológicos no deseados. Los porcentajes de extracción de otros metales también apuntan a este problema de infiltración. A pesar de esto, el material ofrece buenas cualidades para su uso como material de construcción, como pueden ser sus coeficientes térmicos

    Non-syndromic supernumerary premolars

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    Objective: The objective of this study was to estimate the incidence of non-syndromic supernumerary premolars, to classify them and to identify the complications related to them. Study Design: This retrospective cohort study was composed of 8400 panoramic radiographs of patients who presented at our Oral and Maxillofacial Surgery Services from January 1998 to May 2008. The number of supernumerary premolars, their localization, the ages and the sex of the patients, any associated complications and treatment methods were estimated. Results and Conclusion: A total of 20 supernumerary premolar teeth were found in 10 of the 8400 patients (0.24%) with 7 of those being females and three males. Three patients had pain localized to the mental foramen and one patient had resorption in the root of the adjacent tooth. In these series, 18 supernumerary premolar teeth were extracted. In contrast with previous studies, this study suggested that this phenomenon is more frequently encountered in females than in males. The presence of complications associated with the supernumerary premolars in 4 patients necessitated consideration of surgical intervention as a treatment choice for these teeth. Otherwise, they should be kept under observation. © Medicina Oral S. L

    Unconventional pairings and radial line nodes in inversion symmetry broken superconductors

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    Noncentrosymmetric superconductors (NCSs) with broken inversion symmetry can have spin-dependent order parameters (OPs) with mixed parity which can also have nodes in the pair potential as well as the energy spectra. These nodes are distinct features that are not present in conventional superconductors. They appear as points or lines in the momentum space where the latter can have angular or radial geometries dictated by the dimensionality, the lattice structure and the pairing interaction. In this work we study the nodes in time reversal symmetry (TRS) preserving NCSs at the OP, the pair potential, and the energy spectrum levels. Nodes are examined by using spin independent pairing interactions respecting the rotational C∞v symmetry in the presence of spin-orbit coupling (SOC). The pairing symmetries and the nodal topology are affected by the relative strength of the pairing channels which is studied for the mixed singlet-triplet, pure singlet, and pure triplet. Complementary to the angular line nodes widely present in the literature, the C∞v symmetry here allows radial line nodes (RLNs) due to the nonlinear momentum dependence in the OPs. The topology of the RLNs in the mixed case shows a distinctly different characterization than the half-spin quantum vortex at the Dirac point. We apply this NCS physics to the inversion symmetry broken exciton condensates (ECs) in double quantum wells where the point and the RLNs can be found. On the other hand, for a pure triplet condensate, two fully gapped and topologically distinct regimes exist, separated by a QSHI-like zero energy superconducting state with even number of Majorana modes. We also remark on how the point and the RLNs can be manipulated, enabling an external control on the topology. © 2016 Elsevier B.V

    Multiagent cooperation for solving global optimization problems: an extendible framework with example cooperation strategies

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    This paper proposes the use of multiagent cooperation for solving global optimization problems through the introduction of a new multiagent environment, MANGO. The strength of the environment lays in itsflexible structure based on communicating software agents that attempt to solve a problem cooperatively. This structure allows the execution of a wide range of global optimization algorithms described as a set of interacting operations. At one extreme, MANGO welcomes an individual non-cooperating agent, which is basically the traditional way of solving a global optimization problem. At the other extreme, autonomous agents existing in the environment cooperate as they see fit during run time. We explain the development and communication tools provided in the environment as well as examples of agent realizations and cooperation scenarios. We also show how the multiagent structure is more effective than having a single nonlinear optimization algorithm with randomly selected initial points

    Green Modernization – The political, social and societal setting of Morocco’s solar energy policies

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    In 2009, Morocco initiated an ambitious energy transition program. The aim is to increase the country’s independence from energy imports until 2030. The plan targets the reduction of the import of fossils and large investments into renewable energies. The goal set is to meet 42% of its power generating capacity needs through renewables by 2020 and 52% by 2030. Morocco’s bold and ambitious plans are often highlighted as a model for how to invest into future technologies and bring about clean energy transition. Due to its geography, weather conditions and solar irradiance, Morocco is considered to have huge potentials regarding wind and solar energy production. Morocco’s energy transition program includes the construction of a number of large and medium scale solar plants until 2020. Their planning and construction is often managed by MASEN (Moroccan Agency for Sustainable Energy), a public limited company. Recently, Noor 1, the first of several large scale solar plants was completed. Noor 1 is situated in Ouarzazate in the East of the country. Currently Noor Tata is in the planning phase. Similar with Morocco, energy transition has been also a hot topic in Austria. However, different from Morocco, planning, decision-making and governance structures have rather reflected the country's federal system. Austria's energy transition strategy is a decentralized one. As much as this often entails strong involvement and ownership on societal level, as much its success is dependent on a complex set of diverse political entrepreneurs on different political and administrative levels (national-federal-district and local). LINKS project aims at learning from both; Austrian and Moroccan experiences. In its last phase, the project deals with the question whether decentralized small-scale energy production models as implemented in some of the Austrian energy model regions are transferrable to Morocco. This assessment takes place against the background of the Moroccan state's ambitions to decentralize and strengthen the regional and provincial levels. Accordingly, this report elaborates the structural, political, social and societal setting in which Morocco's energy policy is embedded. The report tries to define the major actors, analyse the decision-making structures, and review the socio-technical imaginaries which have shaped national energy policies. "Socio-technical imaginaries" define mind-sets and frames which do not only guide policies and strategies but also give insights about the expectations connected with technological developments. The report aims at providing a background for the preparation of the stakeholder forum to be held in Tata/Morocco in October 2017. The forum aims at bringing together local and regional stakeholders and to debate at eye level experiences, expectations and ideas for solar energy production in their region. This working paper was produced within the LINKS project (Linking climate change mitigation, energy security and regional development in climate and energy model regions in Austria) (funded by the ACRP)

    Prevalence of impacted premolars in a Turkish population and considerations for surgical treatment

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    Objective: The aim of this study was to identify the prevalence, associated pathology and symptoms, and treatment of impacted premolars in a Turkish population. Study Design: This retrospective study examined panoramic radiographs and clinical records of 9,000 patients who presented consecutively at our oral and maxillofacial surgery clinics between January 1998 and January 2009. In addition to demographic data (patient sex and age), data was compiled on the number and location of impacted missing maxillary and mandibular premolars, retained deciduous molars, associated pathologies and symptoms, and treatment methods. Results: A total of 105 impacted maxillary or mandibular premolars were observed in 93 patients (1.03%). Of these, 48 (51.6%) were female (age range: 13-57 years) and 45 (43.4%) were male (age range: 13-58 years). Impacted mandibular second premolars accounted for 55.2% (n=58) of all impacted premolars. Migration was observed in only 11.83% of patients (n=11). Pathological changes and symptoms were noted in 15.05% of patients. Conclusion: Our results suggest that the prophylactic extraction of non-migrated impacted premolars may not be necessary. If the patient is cooperative, a "wait and see" approach may be preferable. Orthodontic or prosthetic treatment options should also be considered when planning treatment of non-migrated impacted premolars. Migrated impacted premolars should be kept under observation and should only be removed if they are associated with pathology or if extraction is required for prosthetic or orthodontic treatment. © Medicina Oral S. L

    Weakly anisotropic noncentrosymmetric superconductors with radial line nodes and the origin of the anomalous thermodynamic data

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    In noncentrosymmetric superconductors (NCSs), the inversion symmetry (IS) is most commonly broken by an antisymmetric spin-orbit coupling (SOC). Removing the spin degeneracy and splitting the Fermi surface (FS) into two branches. A two component condensate is then produced mixing an even singlet and an odd triplet. When the triplet and the singlet strengths are comparable, the pair potential can have rich nodes. The angular line nodes (ALNs) are associated with the point group symmetries of the anisotropic lattice structure and they are widely studied in the literature. When the anisotropy is weak, other types of nodes can be present which then affect differently the low temperature properties. Here, we focus on the weakly anisotropic NCSs and the line nodes which survive in the limit of full isotropy. We study the topology of these radial line nodes (RLNs) and show that it is characterized by the Z2 index similar to the quantum-spin-Hall Insulators. From the thermodynamic perspective, the RLNs cause, even in the topological phases, an exponentially suppressed low temperature behaviour which can be mistaken by nodeless s-wave pairing, thus, providing an explanation to a number of recent experiments with contraversial pairing symmetries. In the rare case when the RLN is on the Fermi surface, the exponential suppression is replaced by a linear temperature dependence. The RLNs are difficult to detect, and for this reason, they may have escaped experimental attention. We demonstrate that Andreev conductance measurements with clean interfaces can efficiently identify the weakly anisotropic (WA) conditions where the RLNs are expected to be found. ©2017 The Physical Society of Japan
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