44 research outputs found

    Magnetic-Oriented Nickel Particles and Nickel-Coated Carbon Nanotubes: An Efficient Tool for Enhancing Thermal Conductivity of PDMS Composites

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    In this study, PDMS composites are thermally cured with nickel particles and nickel-coated carbon nanotubes as fillers. Both fillers are oriented with the aim to increase the thermal conductivity of the silicone polymer network, due to the formation of a continuous thermal path. Scanning electron microscopy (SEM) gives a picture of the polymer network's morphology, proving the effective alignment of the nickel particles. Rheology and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) studies confirm the full curing of the silicon network and no influence in the curing kinetics of the type and content of fillers and their orientation. Dynamic mechanical thermal analysis (DMTA) and tensile analysis show instead different thermo-mechanical behavior of the polymer network due to the presence of different fillers, different fillers percentage, and orientation. Finally, the thermal transmittance coefficient (k) is studied by means of hot disk analysis, revealing the increment of almost 200% due to magnetic filler orientation

    Vive la difference! the effects of natural and conventional wines on blood alcohol concentrations: A randomized, triple-blind, controlled study

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    Different alcoholic beverages can have different effects on blood alcohol concentration (BAC) and neurotoxicity, even when equalized for alcohol content by volume. Anecdotal evidence suggested that natural wine is metabolized differently from conventional wines. This triple-blind study compared the BAC of 55 healthy male subjects after consuming the equivalent of 2 units of alcohol of a natural or conventional wine over 3 min in two separate sessions, one week apart. BAC was measured using a professional breathalyzer every 20 min after consumption for 2 h. The BAC curves in response to the two wines diverged significantly at twenty minutes (interval T20) and forty minutes (interval T40), and also at their maximum concentrations (peaks), with the natural wine inducing a lower BAC than the conventional wine [T20 = 0.40 versus 0.46 (p < 0.0002); T40 = 0.49 versus 0.53 (p < 0.0015); peak = 0.52 versus 0.56 (p < 0.0002)]. These differences are likely related to the development of different amino acids and antioxidants in the two wines during their production. This may in turn affect the kinetics of alcohol absorption and metabolism. Other contributing factors could include pesticide residues, differences in dry extract content, and the use of indigenous or selected yeasts. The study shows that with the same quantity and conditions of intake, natural wine has lower pharmacokinetic and metabolic effects than conventional wine, which can be assumed due to the different agronomic and oenological practices with which they are produced. It can therefore be hypothesized that the consumption of natural wine may have a different impact on human health from that of conventional wine

    Compact 3-manifolds via 4-colored graphs

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    We introduce a representation of compact 3-manifolds without spherical boundary components via (regular) 4-colored graphs, which turns out to be very convenient for computer aided study and tabulation. Our construction is a direct generalization of the one given in the eighties by S. Lins for closed 3-manifolds, which is in turn dual to the earlier construction introduced by Pezzana's school in Modena. In this context we establish some results concerning fundamental groups, connected sums, moves between graphs representing the same manifold, Heegaard genus and complexity, as well as an enumeration and classification of compact 3-manifolds representable by graphs with few vertices (≤6\le 6 in the non-orientable case and ≤8\le 8 in the orientable one).Comment: 25 pages, 11 figures; changes suggested by referee: references added, figure 2 modified, results about classification of the manifolds in Proposition 17 announced at the end of section 9. Accepted for publication in RACSAM. The final publication is available at Springer (see DOI

    The use of optical scanner for the fabrication of maxillary obturator prostheses

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    Introduction: Maxillectomy following tumors or, more rarely, traumatic injuries may result in maxillary defects that may determine physical dysfunctions and functional impairment of speech and swallowing. The aim of our study was to present our experience in the management of post-maxillectomy patients by the use of obturator prostheses that were obtained by 3D digital casts via an intraoral scanner. Methods: Patients with maxillary defects following maxillary and/or palatal resection or maxillary traumatic avulsion were selected for this clinical study between 2015 and 2018. Five to 6\ua0months after surgery, a definitive obturator prosthesis was fabricated thanks to an intraoral scanner. The following parameters of clinical outcome were considered: the absence of fluid leakage, the recovery of phonation, the recovery of swallowing, and personal satisfaction. Results: Twenty-eight patients (20 males, 8 females) fulfilled the inclusion criteria and were included in the study. Most patients had a maxillary and/or palatal defect because of a malignant tumor. On the whole, 93% of patients reported a complete absence of fluid leakage between maxillary sinuses or nasal fossa and oral cavity; most patients reported a good or complete recovery of phonation and swallowing. Conclusions: Digital technology for the fabrication of maxillary obturator prosthesis may be effective and useful. The reduced laboratory working time, the avoidance of the risk of aspiration of impression materials, and the overcome of the difficulties associated with whole tissue undercut impression are just some of the most important advantages that have been encountered thanks to this promising technology

    Epidermoid cyst of the upper eyelid

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    Epidermoid cysts are subcutaneous lesions that arise from epidermal cells' proliferation within a confined space and subsequent cystic transformation. They are usually slow growing and have a benign behavior. Clinically, they appear as a smooth, soft and movable lesion and are often asymptomatic. A central pore connects the cyst to the overlying skin that appears smooth. Epidermoid cysts are quite common and can be usually found on the face, head and neck, trunk and genitals. Eyelid are more unusual locations for epidermoid cyst. The purpose of this article was to present and discuss the management of an epidermoid cyst of the upper eyelid in a 58-year-old man

    Chainsaw injuries of the maxillofacial region: Our experience

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    The inappropriate use of chainsaws may determine severe facial injuries. The aim of this article was to present and discuss our experience in the management of chainsaw-related maxillofacial injuries. Aretrospective analysis of patients that had been victims of chainsaw related facial injuries was performed. Clinical and demographic data were recorded. Four men were included in the study. Accident by self-injuring was the only mechanism of all analyzed injuries. In most patients, soft tissue injuries were compounded with bone fractures of the face. The management included the intravenous administration of antibiotics, soft tissue management and suture, and open reduction and internal fixation in addition to soft tissue management. Athorough knowledge of the mechanisms and of the appropriate steps of management may help to avoid complications. Preventive measures such as education of chainsaw users may be crucial for a safe use of this devices
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