Oxygen reduction in acid media: effect of iron substitution by cobalt on heat-treated naphthalocyanine impregnations supported on preselected carbon blacks

FeNPc(1.2) impregnations were investigated at various loadings using a rotating-disk electrode, voltammetry and X-ray photoelectron spectroscopy (XPS) techniques. Optimal activity takes place at monolayer coverage, and major demetallation occurs after prolonged exposure to acid solution. The substitution of Fe by Co enables the electrochemical performances to reach those presented by 10% Pt on Vulcan and stops the demetallation process. The application of fast atomic bombardment secondary ion mass spectrometry (FABS) together with XPS sheds light on the detrimental role of some electrophilic groups attached to the carbon black-catalyst interface

Oxygen reduction in acid media on supported iron naphthalocyanine: Effect of isomer configuration and pyrolysis

O2 reduction in H2SO4 medium has been investigated on FeNPc impregnations on Norit BrX by the rotating disk electrode technique. Important differences in activity and stability were found between the 1,2- and 2,3-FeNPc isomers (pyrolysed or not). XPS analyses show, for the most inactive sample, strong demetallation and nitrogen losses. This phenomenon can be attributed to the differences in flexibility between the FeNPc isomers, which influences their stabilization on the substrate

Oxygen reduction in acid media: influence of the heat treatment on the FeNPc(1–20 isomer mixture impregnated on carbon blacks and active charcoals

Oxygen reduction with the aid of a number of FeNPc(1–2) impregnated carbon supports in sulphuric acid solutions has been investigated.\ud \ud Loading of the carbon samples amounted to about 10 wt.%. After a 10 day stay in the aerated solutions the samples were investigated with rotating disk electrode and X-ray photoelectron spectroscopy techniques. The most active and stable samples correspond to mono- or submonolayers of FeNPc deposited on high dibutylphthalate adsorption carbon blacks. Comparison with data obtained previously on Norit BrX impregnations emphasizes the rôle of the electron density on the inner nitrogen atoms rather than that on the iron centres

Designing Urban Spaces to Enhance Active and Sustainable Mobility: An Analysis of Physical and Symbolic Affordances in School Squares in the Metropolitan Area of Milan, Italy

As thresholds to cities, public spaces adjacent to schools play an important role in children’s everyday mobilities, potentially shaping their future mobility habits and affective experiences. The purpose of this paper is to investigate the urban design conditions of such spaces, defined as “school squares”, and, with the aid of affordance theory, to analyze spatial features and characteristics that might encourage or hinder active and sustainable mobility practices. In the first part of the paper, we define sustainable mobility, conduct a literature review on affective responses to the urban environment, and discuss active school travel (AST) in relation to the design of school squares. By focusing on 416 primary and lower secondary schools in the metropolitan area of Milan, we present an assessment method that is composed of on-desk and on-site surveys. In particular, Phase 1 defines the type of school squares, Phase 2 investigates physical affordances (spatial features and characteristics that directly influence active mobility practices, such as bicycle racks, protective barriers, benches, and parked cars), and Phase 3 discusses symbolic affordances (elements and characteristics that might induce different affective responses to a school square with regard to active mobility, such as bicycle racks, parked cars, greenery, and dustbins). The results indicate that in most cases school squares are characterized by typological confusion that has nothing to do with the school environment: narrow sidewalks, disorder, and low levels of safety. In order to promote active and sustainable mobility choices and enhance children’s mobile experiences, it is necessary to address the aforementioned features. The ultimate goal of this paper is to provide insights for developing an urban regeneration framework that considers school squares a safe context and a starting point from which to perform sustainable mobility practices

Oxygen reduction in an acid medium : electrocatalysis by CoNPc(1,2) impregnated on a carbon black support; effect of loading and heat treatment

O2 reduction in an acid medium has been investigated on a transition metal macrocycle, CoNPc(1,2), impregnated on a carbon black support with a high dibutylphthalate adsorption value, using a rotating disk electrode and voltammetry techniques described previously, combined with X-ray photoelectron spectroscopy measurements. Optimal activity was found for a bilayer coverage (n = 2) at 17%-18% w/w loading. Heat treatment seems to be beneficial for n 3: it increases the overall number N of exchanged electrons and improves the electrode wetting. For the most active samples, mixed Co(II)/Co(III) valencies were displayed

Comparing the performance of conventional and robotic catheters in transcatheter aortic valve implantation

In this paper we investigate the performance of a recently developed robotic catheterization platform in comparison to conventional surgical equipment. Transcather aortic valve implantation (TAVI) was chosen as the test case and 12 interventionists (6 experts and 6 novices) participated in experiments with a silicon aorta model. Video sequences of the fluoroscopic monitor, used for guiding the instruments, were captured and processed with specialized software. To evaluate and compare the two systems the 2-D position of the catheter/guidewire tip is tracked and the shape of the phantom model is extracted in the video frames. In our analysis, we focus on three metrics; the procedure time, the average speed and the average distance to the vessel wall. The obtained results show that procedure time is capable of discriminating the participants of the different experience groups, achieving p=0.008 in the first stage of the experiment. In addition, experts consistently exhibit a higher average speed than novices. Ultimately, the increased average distance to the vessel wall demonstrated by the robotic system is an indication of improved precision and safer catheter/guidewire navigation

Clinical applications of robotic technology in vascular and endovascular surgery

BackgroundEmerging robotic technologies are increasingly being used by surgical disciplines to facilitate and improve performance of minimally invasive surgery. Robot-assisted intervention has recently been introduced into the field of vascular surgery to potentially enhance laparoscopic vascular and endovascular capabilities. The objective of this study was to review the current status of clinical robotic applications in vascular surgery.MethodsA systematic literature search was performed in order to identify all published clinical studies related to robotic implementation in vascular intervention. Web-based search engines were searched using the keywords “surgical robotics,” “robotic surgery,” “robotics,” “computer assisted surgery,” and “vascular surgery” or “endovascular” for articles published between January 1990 and November 2009. An evaluation and critical overview of these studies is reported. In addition, an analysis and discussion of supporting evidence for robotic computer-enhanced telemanipulation systems in relation to their applications in laparoscopic vascular and endovascular surgery was undertaken.ResultsSeventeen articles reporting on clinical applications of robotics in laparoscopic vascular and endovascular surgery were detected. They were either case reports or retrospective patient series and prospective studies reporting laparoscopic vascular and endovascular treatments for patients using robotic technology. Minimal comparative clinical evidence to evaluate the advantages of robot-assisted vascular procedures was identified. Robot-assisted laparoscopic aortic procedures have been reported by several studies with satisfactory results. Furthermore, the use of robotic technology as a sole modality for abdominal aortic aneurysm repair and expansion of its applications to splenic and renal artery aneurysm reconstruction have been described. Robotically steerable endovascular catheter systems have potential advantages over conventional catheterization systems. Promising results from applications in cardiac interventions and preclinical studies have urged their use in vascular surgery. Although successful applications in endovascular repair of abdominal aortic aneurysm and lower extremity arterial disease have been reported, published clinical experience with the endovascular robot is limited.ConclusionsRobotic technology may enhance vascular surgical techniques given preclinical evidence and early clinical reports. Further clinical studies are required to quantify its advantages over conventional treatments and define its role in vascular and endovascular surgery

In situ observations on the dentition and oral cavity of the Neanderthal skeleton from Altamura (Italy)

The Neanderthal specimen from Lamalunga Cave, near Altamura (Apulia, Italy), was discovered during a speleological survey in 1993. The specimen is one of the most complete fossil hominins in Europe and its state of preservation is exceptional, although it is stuck in calcareous concretions and the bones are mostly covered by calcite depositions. Nevertheless, it is possible to carry out some observations on craniodental features that have not previously been described. In this work, we present an account of the oral cavity, made possible by the use of a videoscope, which allowed us to reach some hidden parts of the mandible and palate. This is the first detailed overview of the teeth and maxillary bones of the Neanderthal skeleton from Altamura. The dentition is almost complete. However, two teeth (upper right P3 and upper left M1) were lost ante mortem and four teeth (lower right I1 and P3 and lower left I1 and I2) were lost most probably post mortem. Dental wear is marked. The erupted M3s and the inversion of the compensating curve of Wilson in the M1s and M2s but not in the M3s suggest that the individual is fully adult, but not old. Although most of the teeth have their roots exposed for several millimeters, the periodontal bone appears to be in good condition overall, except in correspondence of the two ante-mortem tooth losses. X-rays of the anterior teeth show a periapical lesion, probably linked to the advanced dental wear. We also observed a weak expression of taurodontism in the posterior dentition and the presence of a retromolar space, features consistent with an attribution to the Neanderthal hypodigm; this attribution is also supported by aspects of the cranial morphology, the morphometric analysis of the scapula and preliminary mtDNA data. There is also a well-developed palatine torus, to the best of our knowledge a feature not previously described in Neanderthals

Tafonomía del titanosaurio Aeolosaurus colhuehuapensis, Cretácico Superior, Patagonia central, Argentina: un ejemplo de preservación en facies fluviales de desbordamiento

Aeolosaurus colhuehuapensis es un titanosaurio procedente del lago Colhué Huapi, en el Sur de Chubut, Argentina. Los materiales estudiados incluyen veintiuna vértebras caudales y siete hemapófisis, y se hallaron articulados en facies correspondientes a depósitos de desbordamientos vinculados a sistemas fluviales multicanalizados y de alta sinuosidad presentes en los aquí denominados ?estratos del lago Colhué Huapi? de edad Campaniano-Maastrichtiano. Estos sistemas poseían importantes fluctuaciones estacionales en la paleodescarga y estaban enmarcados en un clima semi-árido. La historia tafonómica fue inferida a partir del análisis de diversas características presentes en los restos y de observaciones sedimentológicas macro y microscópicas. La presencia tenue de estriamiento longitudinal, la escasa exfoliación, el grado de articulación y el arqueamiento dorsal de la serie caudal, sugieren un corto tiempo de exposición subaérea y rápido sepultamiento. La falta de marcas de abrasión en los elementos conservados indica escaso o nulo transporte, por lo que los mismos podrían ser considerados autóctonos. El curvamiento dorsal de la cola muestra un arqueamiento opistótono, también presente en algunos terópodos y saurópodos, pero aun no documentado en el Grupo Chubut. Las condiciones climáticas actuales, con variaciones de extrema humedad y sequía, afectaron marcadamente los elementos fósiles preservados. El presente trabajo constituye el primer caso de estudio tafonómico en detalle de un dinosaurio preservado en facies de planicie de inundación proximal para el Grupo Chubut. Finalmente, el hallazgo de saurópodos en estas facies es relevante, dado que este tipo de subambiente posee una alta tasa de aporte sedimentario y reducido a nulo retrabajo de los restos óseos, favoreciendo la preservación de elementos esqueletales articulados. Esto es de suma importancia para el análisis taxonómico y filogenético del clado de los titanosaurios, donde la mayoría de los taxones están representados por restos desarticulados y aislados. Palabras clave: Tafonomía, Postura opistótona, Titanosauria, Patagonia.Fil: Casal, Gabriel A.. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Ibiricu, Lucio Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Allard, Jose Oscar. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Martínez, Rubén D.. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Luna, Marcelo. Universidad Nacional de la Patagonia "san Juan Bosco"; ArgentinaFil: Gonzalez Riga, Bernardo Javier. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Científico Tecnológico Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin