1,721,038 research outputs found
Free flaps in head and neck reconstruction. A step-by-step color atlas.
No full textThis richly illustrated atlas provides a clear and comprehensive step-by-step description of surgical techniques for raising and setting free flaps from different donor sites, to reconstruct damage to the head and neck caused by cancer and trauma. Adopting a highly practical approach, the book describes the indications and technical aspects of each procedure with sets of in-vivo pictures clearly showing the surgical passages. In addition, it discusses microvascular techniques and explores different soft-tissue, perforator and bone flaps, including novel free tissue flaps, presented for the first time in the head and neck field. This book offers invaluable insights into free-flap harvesting and transferring techniques for both residents and experienced specialists in the field of otolaryngology, head and neck, maxillo-facial and plastic surgery
Free flaps in head and neck reconstruction. A step-by-step color atlas
No full textThis richly illustrated atlas provides a clear and comprehensive step-by-step description of surgical techniques for raising and setting free flaps from different donor sites, to reconstruct damage to the head and neck caused by cancer and trauma. Adopting a highly practical approach, the book describes the indications and technical aspects of each procedure with sets of in-vivo pictures clearly showing the surgical passages. In addition, it discusses microvascular techniques and explores different soft-tissue, perforator and bone flaps, including novel free tissue flaps, presented for the first time in the head and neck field. This book offers invaluable insights into free-flap harvesting and transferring techniques for both residents and experienced specialists in the field of otolaryngology, head and neck, maxillo-facial and plastic surgery
Analyzing the effectiveness of quantum annealing with meta-learning
Full text linkThe field of Quantum Computing has gathered significant popularity in recent years and a large number of papers have studied its effectiveness in tackling many tasks. We focus in particular on Quantum Annealing (QA), a meta-heuristic solver for Quadratic Unconstrained Binary Optimization (QUBO) problems. It is known that the effectiveness of QA is dependent on the task itself, as is the case for classical solvers, but there is not yet a clear understanding of which are the characteristics of a problem that make it difficult to solve with QA. In this work, we propose a new methodology to study the effectiveness of QA based on meta-learning models. To do so, we first build a dataset composed of more than five thousand instances of ten different optimization problems. We define a set of more than a hundred features to describe their characteristics and solve them with both QA and three classical solvers. We publish this dataset online for future research. Then, we train multiple meta-models to predict whether QA would solve that instance effectively and use them to probe which features with the strongest impact on the effectiveness of QA. Our results indicate that it is possible to accurately predict the effectiveness of QA, validating our methodology. Furthermore, we observe that the distribution of the problem coefficients representing the bias and coupling terms is very informative in identifying the probability of finding good solutions, while the density of these coefficients alone is not enough. The methodology we propose allows to open new research directions to further our understanding of the effectiveness of QA, by probing specific dimensions or by developing new QUBO formulations that are better suited for the particular nature of QA. Furthermore, the proposed methodology is flexible and can be extended or used to study other quantum or classical solvers
Towards Improved QUBO Formulations of IR Tasks for Quantum Annealers
Full text linkIn recent years the interest in applying Quantum Computing to Information Retrieval and Recommendation Systems task has increased and several papers have proposed formulations of relevant tasks that can be solved with quantum devices (community detection, feature selection etc.), usually focusing on Quantum Annealers (QA), a special purpose device able to solve combinatorial optimization problems. However, most research only focuses on the mathematical aspect of the formulation, without accounting for the underlying physical processes of the quantum device. Indeed, theoretical studies indicate that certain characteristics make a problem difficult to solve on QA, but it is not clear how to use this knowledge to inform the development of better problem formulations that are equivalent but easier to solve on QA. This work presents a preliminary study which approaches this issue with an empirical perspective. We consider several problems both general and related to IR and Recommendation tasks to assess whether we can identify characteristics of the problem formulation or the solution space that affect the effectiveness of QA. The results indicate interesting correlations and suggest that this is a promising area to investigate further
Does the structure of the QUBO problem affect the effectiveness of quantum annealing? An empirical perspective
Full text linkIn recent years there has been a significant interest in exploring the potential of Quantum Annealers (QA) as heuristic solvers of Quadratic Unconstrained Binary Optimization (QUBO) problems. Some problems are more difficult to solve on QA and understanding why is not straightforward, because an analytical study of the underlying physical system is intractable for large QUBO problems. This work consists in an empirical analysis of the features making a QUBO problem difficult to solve on QA, based on clusters of QUBO instances identified with Hierarchical Clustering. The analysis reveals correlations between specific values of the features and the ability of QA to solve effectively the instances. These initial results open new research opportunities to inform the development of new AI methods supporting quantum computation (e.g., for minor embedding or error mitigation) that are better tailored to the characteristics of the problem, as well as to develop better QUBO formulations for known problems in order to improve the quality of the solutions found by QA
Electrochemotherapy: a well-accepted palliative treatment by patients with head and neck tumours
Full text linkElectrochemotherapy (ECT) is a well established treatment strategy for skin tumuors. The aim of this study was to evaluate the feasibility and efficacy of electrochemotherapy in the palliative setting in patients with head and neck malignancies, in terms of improvement of quality of life and in control of pain and bleeding. Twenty-four patients with a loco-regional M0/M1 relapse not suitable for cure with radical intent by surgery or radiotherapy (RT) and not suitable for systemic therapy and/or already treated with it, were admitted to ECT protocol treatment. Clinical features, treatment response, and adverse effects were evaluated. An overall response of 100% was observed. Overall survival probability at 24 months was 46.5% (median OS: 9 months). The multiple application of ECT was associated with improved survival (p = 0.02). Pain, need for medical assistance or dressing and bleeding events was significantly reduced at 1 month after ECT (p < 0.001). ECT is effective as palliative treatment of non-resectable head and neck malignancies. Its main advantages are improved quality of life, local tumour control and limited side effects
MRI features in submandibular gland chronic sclerosing sialadenitis: A report of three cases and imaging findings
No full textIntroduction: Chronic sclerosing sialadenitis (Küttner tumor) is a relatively uncommon and often under-recognized cause of salivary gland enlargement, characterised by sclerosing IgG4-related inflammation, producing a hard swelling of the gland that mimics malignancy. The name tumor is tricky and misleading, in fact the disease has no histological features of malignancy, but still it cannot easily be distinguished from cancer because of its hard consistency to touch. Case Reports: We aim to report three cases of Küttner tumor and to review morphological MRI features (homogeneous T1- and T2-hypointensity, homogeneous contrast enhancement) and diffusion weighted imaging findings (low ADC values) which can help radiologists to reach the correct diagnosis. Conclusion: Definite diagnosis of Küttner tumor is histopathological. However imaging features are straightforward and can address radiologists toward the correct diagnosis
Elective treatment of the neck in squamous cell carcinoma of the larynx: clinical experience
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