On Narrative: An Interview with Roland Barthes

his article presents a dialogue between Roland Barthes and Paolo Fabbri, which took place on 18 December 1965 in Florence, Italy. Barthes offers an engaging account of his structuralist approach to narrative, as was later published in essay form, ‘Introduction to the Structural Analysis of Narrative’, included in a special issue of Communications (Issue 8, 1966). In a cordial exchange with Fabbri, Barthes provides a more candid presentation of method than found in print, along with critical reflection of the underlying importance of the structuralist approach, as perceived at the time. The interview took place as part of a small conference on narrativity. Participants included Algirdas Julien Greimas, Claude Bremond, Umberto Eco, Jules Gritti, Violette Morin, Christian Metz, and Tzvetan Todorov. Subsequently, a number of these participants contributed articles to the same issue of Communications, on the structural analysis of narrative

HyFlex EDM rotary Ni-Ti prototypes: the effect of an innovative machining technology on Ni-Ti wear

Aim. HyFlex EDM files were recently introduced pre- senting an innovative electro discharge machining (EDM) process of fabrication. The aim of this study was to evalua- te the surface and microstructural alterations of new and in vitro used HyFlex EDM Ni-Ti rotary prototypes. Methods. The surface and microstructural characteristi- cs of 15 new HyFlex EDM instruments were analyzed by ESEM equipped with energy dispersive x-ray spectropho- tometry (EDS) and optical metallographic imaging. Instru- ments were subjected to instrumentation tests on severely curved root canals (ranging between 50° and 70°) of ex- tracted multi-rooted teeth. Once that canal patency was verified with a #10 K-file, the working length was determi- ned by subtracting 1mm. HyFlex EDM files were used with a 16:1 reduction handpiece X-Smart (Dentsply Maillefer, Baillagues, Switzerland) following the manufacture’s direc- tion, at 500 rpm and 2.5Ncm, with slightly apical pressure and pecking motion. The operative sequence was: 25/12 at 2/3 of the WL, 10/05 and 25/08 at WL. Irrigation was per- formed at every change of instrument, with a total amount of3mlof5%NaOCland3mlof10%EDTA(Ogna,Mug- giò, Italy). Each instrument was used in 10 curved canals, washed in an ultrasonic bath containing detergent for 10 min and then autoclaved at 134°C. Surface and microstruc- tural characterizations were repeated on used instruments at same points and with same angulations to compare the pre- and postoperative micrographs, in order to verify the appearance of fractures, unwinding, microcracks, blade di- sruption and tip deformation. Results. Surface and microstructural characteriza- tion of new instruments revealed the typical features of a NiTi ED-Machined alloy with an irregular and “craters-like” surface. High magnification microgra- phs disclosed a non-uniform structure were pits, po- res and voids caused the peculiar aspect of a “rough- spark-machined” surface. No fractures were registered during instrumentation of curved canals. Surface and microstructural characterization of used files revealed no wear and no degradation of the 25.12 and 25.08 files. The tip segment was confirmed as the most me- chanically stressed portion of 10.05 prototypes. All the instruments, after several uses, well-preserved the “craters-like” irregular surface without cutting edge al- terations. The metallographic inspection on the cross section of brand new HyFlex EDM files showed an homogeneous martensitic phase. The microstructure appeared uniform from the surface to the bulk, and no microcracks or defect were identified, even at high optical magnification (1000X). Conclusion. Unaltered spark-machined surface and low microstructural degradation are the main features of recently introduced HyFlex EDM. Caution would be re- commended regarding reuse of small HyFlex EDM files. Instruments exhibited a safe in vitro use in presence of severely curved canals

Endoscopic full-thickness resection for suspected residual rectal neuroendocrine tumor and closure of the defect with a new suturing system

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Esophageal involvement by pemphigus vulgaris resulting in dysphagia

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Endosonographically guided gallbladder drainage to treat neoplastic jaundice after Roux-en-Y gastric resection

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Push-out bond strength and SEM fractographical analysis of hollow fibre posts used with self-adhesive resin cement: a pilot study

Detachment is the major cause of failure of endodontic fibre posts. Hollow posts have been recently introduced to overcome such issue. The primary aim of this pilot study was to compare the push-out bond strength of hollow posts and traditional solid posts. Eight round-shaped single-canal premolars extracted for periodontal reason were selected as sample and equally randomized into two groups: (i) traditional solid fibre posts-TECH21xop and ii) hollow fibre posts-TECHOLE. A dual-curing self-adhesive cement (new TECHCEM) was used for posts placement. Six horizontal sections-two from each portion of the root (coronal, middle and apical)-were obtained from each sample root, yielding a total of 24 sections for each group. Push-out test was performed on the sections and bond strength values were compared between groups and within each group. Scanning electron microscope (SEM) fractographical analysis was conducted on each section. Additional SEM and EDX analyses were performed on new samples of both posts, to assess fibres density and distribution, and the chemical composition of the fibres and the matrix. Hollow posts showed a significantly higher push-out bond strength (6.36 +/- 1.22 MPa) than solid posts (3.64 +/- 1.62 MPa). Among the three root portions of the same group, there was no significant difference in bond strength. In both groups, the most frequent type of fracture was a mixed adhesive failure with the cement covering 0 to 50% of the post perimeter. Hollow post fibres appear more similar in size and have a more homogeneous distribution, compared to solid posts. The two post types also have different chemical compositions

Sliding and abrasive wear behaviour of HVOF- and HVAF-sprayed Cr3C2-NiCr hardmetal coatings

This paper provides a comprehensive characterisation of HVOF- and HVAF-sprayed Cr3C2-25 wt.% NiCr hardmetal coatings. One commercial powder composition with two different particle size distributions was processed using five HVOF and HVAF thermal spray systems. All coatings contain less Cr3C2 than the feedstock powder, possibly due to the rebound of some Cr3C2-rich particles during high-velocity impact onto the substrate. Dry sand-rubber wheel abrasive wear testing causes both grooving and pull-out of splat fragments. Mass losses depend on inter- and intra-lamellar cohesion, being higher (≥70 mg after a wear distance of 5904 m) for the coatings deposited with the coarser feedstock powder or with one type of HVAF torch. Sliding wear at room temperature against alumina involves shallower abrasive grooving, small-scale delamination and carbide pull-outs, and it is controlled by intra-lamellar cohesion. The coatings obtained from the fine feedstock powder exhibit the lowest wear rates (≈5×10-6 mm3/(Nm)). At 400 °C, abrasive grooving dominates the sliding wear behaviour; wear rates increase by one order of magnitude but friction coefficients decrease from ≈0.7 to ≈0.5. The thermal expansion coefficient of the coatings (11.08×10-6 °C-1 in the 30-400 °C range) is sufficiently close to that of the steel substrate (14.23×10-6 °C-1) to avoid macro-cracking

Tribology of HVOF- and HVAF-sprayed WC-10Co4Cr hardmetal coatings: A comparative assessment

This paper provides a comprehensive assessment of the sliding and abrasive wear behaviour of WC-10Co4Cr hardmetal coatings, representative of the existing state-of-the-art. A commercial feedstock powder with two different particle size distributions was sprayed onto carbon steel substrates using two HVOF and two HVAF spray processes. Mild wear rates of <10-7mm3/(Nm) and friction coefficients of 480.5 were obtained for all samples in ball-on-disk sliding wear tests at room temperature against Al2O3 counterparts. WC-10Co4Cr coatings definitely outperform a reference electrolytic hard chromium coating under these test conditions. Their wear mechanisms include extrusion and removal of the binder matrix, with the formation of a wavy surface morphology, and brittle cracking. The balance of such phenomena is closely related to intra-lamellar features, and rather independent of those properties (e.g. indentation fracture toughness, elastic modulus) which mainly reflect large-scale inter-lamellar cohesion, as quantitatively confirmed by a principal component analysis. Intra-lamellar dissolution of WC into the matrix indeed increases the incidence of brittle cracking, resulting in slightly higher wear rates. At 400\ub0C, some of the hardmetal coatings fail because of the superposition between tensile residual stresses and thermal expansion mismatch stresses (due to the difference between the thermal expansion coefficients of the steel substrate and of the hardmetal coating). Those which do not fail, on account of lower residual stresses, exhibit higher wear rates than at room temperature, due to oxidation of the WC grains.The resistance of the coatings against abrasive wear, assessed by dry sand-rubber wheel testing, is related to inter-lamellar cohesion, as proven by a principal component analysis of the collected dataset. Therefore, coatings deposited from coarse feedstock powders suffer higher wear loss than those obtained from fine powders, as brittle inter-lamellar detachment is caused by their weaker interparticle cohesion, witnessed by their systematically lower fracture toughness as well

Submucosal tunneling endoscopic resection of a gastric gastrointestinal stromal tumor

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Impianti ibridi in pazienti sani e parodontalmente compromessi: studio clinico e radiografico preliminare

Questo studio clinico e radiologico preliminare ha esaminato la sopravvivenza, la perdita di osso marginale (MBL) e l’influenza dell’altezza dell’abutment protesico (AH) sulla MBL intorno a impianti ibridi posizionati in due gruppi di pazienti parzialmente edentuli: pazienti parodontalmente sani (HP) e parodontalmente compromessi (PCP). In totale, sono stati trattati 93 pazienti che necessitavano di restauri implantari singoli o multipli, in entrambe le arcate, con applicazione di restauri protesici cementati. Sono stati posizionati 54 impianti (35 nell’arcata superiore e 19 in quella inferiore) in 45 HP e 56 impianti (31 nell’arcata superiore e 25 in quella inferiore) in 48 PCP. Tutti i 110 impianti ibridi posizionati in osso intatto hanno fatto registrare una percentuale di sopravvivenza del 100% sia negli HP sia nei PCP. Non sono state registrare differenze statistiche nel confronto dei valori di MBL dell’arcata superiore con quelli dell’arcata inferiore. In HP e PCP, è stata registrata una quantità similare e limitata di MBL ed è stato trovato che maggiore era l’AH, minore era la MBL. In conclusione, i risultati indicano che gli impianti ibridi esaminati possono ridurre il rischio di perimplantite dovuta alla superfici coronali macchinate e migliorare l’osteointegrazione grazie alle loro superfici apicali ruvide