3,524 research outputs found
Evoluzione e tendenze nei filtri d'aria: integrazione tra attività di ricerca e di controllo della qualità
No full textPalatal graft harvesting techniques: A narrative review
No full textOBJECTIVES According to the American Acade my of Periodontology, soft tissue grafting consists of harvesting soft tissue that is completely detached from the donor site and placed in a properly prepared recipient bed. The harvesting of soft tissue from the palate is a technique used in periodontics for over fifty years and still in continuous evolution. From free gingival grafting to bilaminar techniques with connective tissue only or free gingival grafts disepithelized extra-orally, several techniques have been proposed over the years, some of which are now part of today’s periodontal plastic surgery. These techniques are designed to increase periodontal soft tissue thickness, restore a proper keratinized tissue width, correct muco-gingival deformities, improve aesthetics, allow correction of peri-implant de hiscences, soft tissue augmenta tion and ridge preservation, in or der to limit post-extraction bone crest alteration in aesthetically rel evant areas. MATERIALS AND METHODS This narrative review considers the main techniques of soft tissue harvesting from the palate as described in the literature, from the trap-door proposed by Edel in 1974 to the free gingival graft disepithelialized extra-orally proposed by Zucchelli, through a series of single incision techniques introduced over the years. The examination of the grafting techniques is followed by the analysis of the donor area (lateral palate or maxillary tuber) in terms of tissue quality, composition and thickness, difficulties and complications of the surgery. Wound healing and post-operative discomfort are also explored, evaluating the main differences between techniques involving an epi thelial-connective graft and techniques involving only a connective graft. In particular, the use of donor site protectors, such as cyanoacrylate adhesives and PRF (Platelet-Rich Fibrin), is considered. Finally, possible complications are considered − from intra-operative and post-operative bleeding, treatable by compression with wet gauze and tranexamic acid − to less frequent complications such as flap laceration and donor site infection. RESULTS AND CONCLUSIONS The most indicated technique seems to be the harvesting of an extra-orally disepithelized free gingival graft. This bilaminar technique, besides having shown the best clinical results, is also easier to perform, in a reduced operative time and with a lower risk of damaging vascular structures; moreover, the graft composition is richer in connective tissue, without contamination of adipose or glan dular tissue of lower quality. On the other hand, its harvesting technique implies second inten tion healing at the donor site, which may be less comfortable for the patient, but without increasing post-operative pain. In addition, the use of a donor site protection appears to further reduce possibile post-operative patient morbidity. CLINICAL SIGNIFICANCE The use of an extra-orally disepithelized free gingival graft as part of a bilaminar technique can be considered the gold standard among the soft tissue augmentation techniques, possibly accompanied by the use of donor site protections
Delamination localisation and length estimation in composite laminate beam by VSHM and pattern recognition methods
No full textThe focus of this work is to investigate the delamination damage in laminate composite beams, to fix a Vibration-based structural health monitoring (VSHM) method for the laminate structures. The analysis is concentrated on the vibration characteristics of the samples and, in particular, the attention is addressed on the first several natural frequencies of a composite laminate beam with a delamination damage. The core of this work is an experimental investigation on the vibration response of a composite laminate beam and its changes caused by delaminations with different sizes and in different locations of the beam. The study is divided in 3 sections: delamination detection, delamination localization, and delamination estimate. The aim is to determine how the first six harmonics frequencies change due to the delamination, and the results show that they can be successfully used to investigate the presence, the location and the dimensions of the delamination in a composite beam. A Pattern Recognition analysis is used to locate the damage, while the detection and the evaluation are done using the changes in the harmonic frequencies. A finite element analysis is performed, and the variations of the natural frequencies due to delamination are in good agreement with the experimental results
3-D Vertical Resistive Switching Random Access Memory (3D-VRRAM) With Multilevel Programming for High-Density, Energy-Efficient In-Memory Computing
No full textResistive random access memory (RRAM) devices offer a broad range of attractive properties for in-memory computing (IMC) applications, such as nonvolatile storage, low read current, and high scalability. IMC allows to overcome the memory bottleneck of data-intensive workloads, such as deep learning on the edge. In this context, 3-D vertical RRAM (3D-VRRAM) is a promising option to achieve high memory cell capacity with low fabrication cost. In this work, we present an HfOx-based 3D-VRRAM crossbar array (CBA) capable of IMC with precise multilevel programming. We show an extensive experimental demonstration of both matrix–vector multiplication (MVM) and inverse/pseudoinverse matrix calculation via IMC on 3D-VRRAM. To further support the parallel IMC application in real-life scenarios, the work also reports a demonstration of relatively large-size problems adopting 2D-RRAM and SRAM-based memory arrays. These results support 3D-VRRAM for high-density, energy-efficient IMC for edge computing applications
Combination Methods for Software Verification
No full textThe thesis is devoted to the development of formal methods for software verification. Indeed, two are among the most widespread techniques that allow to rigorously specify the possible executions of a system and check whether it contains bugs. On the one hand, the correctness of a program can be guaranteed by showing the unsatisfiability of a formula modulo a theory which usually axiomatizes the involved datatypes; on the other hand, the model checking techniques are used to certify that every possible run of the system satisfies the desired properties. The contributions of the thesis are the following: First of all, we give a decidability result for the constraint satisfiability problem for interesting extensions of the theory of arrays. Secondly, along the lines of Manna and Pnueli, who have shown how a mixture of first-order logic and linear time temporal logic is sufficient to state the verification problems for the class of reactive systems, we draw on the recent literature about the combination of decision procedures to give decidability and undecidability results for the satisfiability problem for logics that allow to plug reasoning modulo first-order theories into a temporal setting. The results obtained in the case of linear flows of time are then generalized to the temporal and modal logics whose relativized satisfiability problem is decidable. The last contribution is the decidability of the model checking problem for linear flows of time under suitable hypothesis over the first-order theories involved. The proofs of the decidability results suggest that efficient Satisfiability Modulo Theories solvers might be successfully employed in the model checking of infinite-state systems
Using a genetic algorithm to derive a highly predictive and context-specific frailty index
No full textThe frailty index (FI) is one of the most widespread tools used to predict poor, health-related outcomes in older persons. The selection of clinical and functional deficits to include in a FI is mostly based on the users' clinical experience. However, this approach may not be sufficiently accurate to predict health outcomes in particular subgroups of individuals. In this study, we implemented an optimization algorithm, the genetic algorithm, to create a highly performant (FI) based on our prediction goals, rather than on a predetermined clinical selection of deficits, using data from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) and 109 potential deficits identified in the dataset. The algorithm was personalized to obtain a FI with high discrimination ability in the prediction of mortality. The resulting FI included 40 deficits and showed areas under the curve consistently higher than 0.80 (range 0.81-0.90) in the prediction of 3-year and 6-year mortality in the whole sample and in sex and age subgroups. This methodology represents a promising opportunity to optimize the exploitation of medical and administrative databases in the construction of clinically relevant frailty indices
Recent Advances in Combined Decision Problems
No full textQuesto articolo vuol essere un'esposizione aggiornata, benché necessariamente parziale, dello stato dell'arte della ricerca relativa all'integrazione modulare di procedure di decisione nella logica elementare. Nello specifico, date due teorie e il cui frammento universale è decidibile, si è
interessati ad individuare quali siano le condizioni che permettono di trasferire tale decidibilità alla teoria ottenuta dall'unione di e . Allo scopo di dare un quadro il più possibile completo ed
approfondito delle ricerche in questo campo, vengono presentati anche risultati sulla possibilità di trasferire alla teoria unione
la decidibilità del problema della parola e viene descritto un ambiente di ordine superiore in cui esprimere svariati problemi
di combinazione. Infine, viene fornita la descrizione ad alto livello di alcune delle tecniche più comunemente utilizzate
nell'implementazione di efficienti sistemi per la combinazione
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