1,720,968 research outputs found
Quantum Bisimilarity via Barbs and Contexts: Curbing the Power of Non-deterministic Observers
Full text linkPast years have seen the development of a few proposals for quantum extensions of process calculi. The rationale is clear: with the development of quantum communication protocols, there is a need to abstract and focus on the basic features of quantum concurrent systems, like CCS and CSP have done for their classical counterparts. So far, though, no accepted standard has emerged, neither for the syntax nor for the behavioural semantics. Indeed, the various proposals do not agree on what should be the observational properties of quantum values, and as a matter of fact, the soundness of such properties has never been validated against the prescriptions of quantum theory. To this aim, we introduce a new calculus, Linear Quantum CCS (lqCCS), and investigate the features of behavioural equivalences based on barbs and contexts. Our calculus can be thought of as an asynchronous, linear version of qCCS, which is in turn based on value-passing CCS. The combination of linearity and asynchronous communication fits well with the properties of quantum systems (e.g. the no-cloning theorem), since it ensures that each qubit is sent exactly once, precisely specifying which qubits of a process interact with the context. We exploit contexts to examine how bisimilarities relate to quantum theory. We show that the observational power of general contexts is incompatible with quantum theory: roughly, they can perform non-deterministic moves depending on quantum values without measuring (hence perturbing) them. Therefore, we refine the operational semantics in order to prevent contexts from performing unfeasible non-deterministic choices. This induces a coarser bisimilarity that better fits the quantum setting: (i) it lifts the indistinguishability of quantum states to the distributions of processes and, despite the additional constraints, (ii) it preserves the expressiveness of non-deterministic choices based on classical information. To the best of our knowledge, our semantics is the first one that satisfies the two properties above
[Tests on ionic release from glass-ionomer cements].
No full textBACKGROUND:
Dissolution process in oral liquids by the presence of glass-ionomer systems (due to surface corrosion, to diffusion through solutions and through mass) make an ionic release (particularly F, Al, Pb, As) which is a non secondary problem, due to the usual utilization of these materials in pedodontic and restorative dentistry.
METHODS:
In this work, considering the high toxicity of low quantity of Arsenic ion, a comparative research has been made in order to determine, by using high level liquid Cromatography (HPCL), the quantity in ppm of As hydro- and acid soluble given by five ionomeric products, in water and in nitric acid concentrated solution.
RESULTS AND CONCLUSIONS:
The results show that in some products arsenical concentrations are higher then the quantity accepted by ISO-FDI; therefore, a better control in the production of these products is needed as well as a limited use in dentistry. It is suggested to use glass-ionomer systems in patients with dental dike and varnish on the surfaces that are in contact with oral liquids action
Testing Quantum Processes
No full textThe recent development of quantum communication protocols calls for adequate modelling and verification techniques, which requires abstracting and focusing on the basic features of quantum concurrent systems. Several quantum process calculi and behavioural equivalences have been proposed to address this problem, but they are often incompatible with the prescriptions of quantum theory, as they implicitly define omniscient observers that are capable of exactly discriminating the state of a physical system, therefore contradicting the uncertainty principle. In this paper, we directly model these observational limitations by resorting to testing equivalence for a quantum capable version of CCS, building on the concrete actions and experiments that a real tester can perform. Thus, we obtain an equivalence notion pairing processes that cannot be distinguished by any physically implementable observer
Postoperative bleeding risk of direct oral anticoagulants after oral surgery procedures: a systematic review and meta-analysis
No full textDirect oral anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban; DOACs) have been introduced to improve safety and superior therapeutic value compared to their predecessors such as warfarin or enoxaparin. The aim of this systematic review and meta-analysis was to assess the postoperative bleeding risk of DOACs during oral surgery procedures. Systematic searches were performed in electronic databases including PubMed, Scopus, Web of Science and Cochrane Library. Thirteen studies were included in the qualitative synthesis: two retrospective case–control studies, five prospective case–control studies, three cross-sectional studies, two case series and a case report; while only six studies were statistically analysed. The risk ratio of postoperative bleeding in DOACs patients was significantly greater than in healthy patients (3.04; 95% confidence interval (CI) = 1.31–7.04). This is especially true for rivaroxaban (4.13; 95% CI = 1.25–13.69), and less so for dabigatran which presented a risk ratio similar to that of healthy patients (1.00; 95% CI = 0.21–4.82). However, further research is required to support these results. Both apixaban and edoxaban were excluded from statistical analysis due to the lack of clinical studies
Index of Orthodontic Treatment Need (IOTN) and distribution of malocclusion traits in a population of growing patients attending a public orthodontic service in Perugia (Italy)
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Peripheral ossifying fibroma: Systematic review and a clinical case presentation
No full textOBJECTIVES The aim of the study is to perform a systematic review of studies about peripheral ossifying fibroma (POF) and to add a new case report. MATERIALS AND METHODS A literature search on PubMed and Scopus was carried out using various keywords. Furthermore, a case of a 10-year old female affected by peripheral ossifying fibroma in the 2.2 tooth region was described. RESULTS AND CONCLUSIONS According to the PRISMA Protocol, 11 results that met the inclusion criteria were obtained. The POF is a gingival reactive hyperplastic lesion with a greater prevalence in the second decade of life with a predisposition for females. The pathogenesis is still unclear and the treatment consists on the enu-cleation of the lesion
Full-mouth adhesive treatment in bulimia-related dental erosions: A clinical case
No full textOBJECTIVES Dental erosion, which is defined as the gradual but irreversible loss of hard tissue is a major dental issue as it may be linked to systemic diseases such as eating disorders or gastroesophageal reflux (GERD), giving rise to difficulties in diagnosis. In both pathological forms, the presence of gastric juices in the oral cavity causes the erosion of the palatal surfaces of the upper elements, often associated with variable sensitivity; carious lesions are generally not associated. Erosions associated with gastroesophageal reflux are often associated with mucosal irritation, oral ulcers and altered taste. It may be due to mechanical or chemical causes, which often lead to problems in treatment. Compared to traditional classifications, the ACE classification sees these lesions divided mainly related to the anterior sector and to the therapeutic intervention strategy. Early diagnosis is crucial to maximize therapeutic alternatives. The treatment of erosions is closely related to the amount of enamel and dentinal tissue involved as well as to the vertical dimension to be obtained in order to obtain satisfactory aesthetic results for the patient. Best erosion treatment involves a multi-disciplinary team and may range from direct composite reconstructions and fixed prostheses to innovative indirect reconstruction systems that aim at preserving as much tissue as possible. The new CAD/ CAM technology offers important advantages in terms of result forecasting, accuracy, precision and better patient-dentist communication. The principle aims of treatment are aesthetic rehabilitation, recovery of functional mastication, establishment of the correct vertical dimension and achievement of stable and reproducible outcomes. In this regard, a multidisciplinary treatment that involves various professional figures would seem to guarantee good and predictable results. MATERIALS AND METHODS The present clinical report describes the treatment of asymptomatic dental erosion in a patient with eating disorders associated with bruxism and cervical myalgia. The patient requested esthetic rehabilitation without invasive interventions. A multi-disciplinary approach included esthetic analysis which was followed by posture assessment using a stabilometric platform and a podoscope. A modified 3-step rehabilitation technique was supported by digital technology. Composite restorations were inserted in the posterior areas and double veneers in the anterior. The outcome was stable and easy to monitor. RESULTS AND CONCLUSIONS The main objectives of prosthetic rehabilitation are preserving as much residual dental tissue as possible and achieving stable occlusal rehabilitation with a multi-disciplinary approach, involving dentists, physiatrists and posturologists. Treatment depends on careful assessment of postural and temporal-mandibular abnormalities, as well as tooth damage. A multidisciplinary approach to gether with the advantages of fered by CAD/CAM technology provides acceptable, predictable outcomes when treating dental erosive lesions. It is often partic ularly problematic to propose in vasive therapeutic solutions, in the absence of relevant clinical symptoms. New technologies, together with adhesive strategies in the pros thetic field, allow the partial over coming of this problem. CLINICAL SIGNIFICANCE The proposed treatment rep resents a valid alternative to more invasive prosthetic reconstructions and highlights the importance of the multidisciplinary approach to the treatment of dental erosions
Autism spectrum disorder and paediatric dentistry: A narrative overview of intervention strategy and introduction of an innovative technological intervention method
No full textAim When treating patients with Autism Spectrum Disorder (ASD) the doctor-patient relationship can be very challenging. The dentist is often forced to work under general anaesthesia or conscious sedation. Children with ASD are patients with an increased risk of caries due to poor oral hygiene, a cariogenic diet and the use of xerostomal drugs. In this work therapeutic strategies used to treat this kind of patients are evaluated and a new method to treat children with ASD is presented in order to increase awareness about this condition in the dental field. Methods The Atlas Center (a non-profit organisation in Peurgia, Italy) has developed a software, called paINTeraction, that allows these special children to immerse themselves in a virtual reality with the help of an operator. Through this system the child can explore the dental office (and all its sounds and noises) before the real dental visit, thus connecting to the dental professional, achieving greater compliance and reducing anxiety. Results The literature shows that performing treatments on ASD patients is complex due to their insufficient cooperation, communication and behavioural difficulties, and hypersensitivity to sensory stimuli. Conclusions paINTeraction, with the use of digital technology tools, may be particularly well suited to introduce patients to the therapeutic environment, particularly in the dental setting
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