624 research outputs found

    Critical thermodynamics of the two-dimensional +/-J Ising spin glass

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    We compute the exact partition function of 2d Ising spin glasses with binary couplings. In these systems, the ground state is highly degenerate and is separated from the first excited state by a gap of size 4J. Nevertheless, we find that the low temperature specific heat density scales as exp(-2J/T), corresponding to an ``effective'' gap of size 2J; in addition, an associated cross-over length scale grows as exp(J/T). We justify these scalings via the degeneracy of the low-lying excitations and by the way low energy domain walls proliferate in this model

    Delayed eruption of permanent dentition and maxillary contraction in patients with cleidocranial dysplasia: review and report of a family

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    Introduction. Cleidocranial dysplasia (CCD) is an inherited disease caused by mutations in the RUNX2 gene on chromosome 6p21. This pathology, autosomal dominant or caused by a spontaneous genetic mutation, is present in one in one million individuals, with complete penetrance and widely variable expressivity. Aim. To identify the incidence of these clinical findings in the report of the literature by means of PubMed interface from 2002 to 2015, with the related keywords. The report of local patients presents a clinical example, related to the therapeutic approach. Results and Discussions. The PubMed research resulted in 122 articles. All the typical signs were reported in all presented cases. The maxilla was hypoplastic in 94% of the patients. Missing of permanent teeth was found in two cases: one case presented a class II jaw relationship, instead of class III malocclusion. Similar findings were present in our cohort. Conclusion. CCD is challenging for both the dental team and the patient. The treatment requires a multidisciplinary approach. Further studies are required to better understand the cause of this disease. According to this review, a multistep approach enhances the possibilities to achieve the recovery of the most possible number of teeth, as such to obtain a good occlusion and a better aesthetic

    Clear aligners: between evolution and efficiency—a scoping review

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    In recent years, clear aligners have diversified and evolved in their primary characteristics (material, gingival margin design, attachments, divots, auxiliaries), increasing their indications and efficiency. We overviewed the brands of aligners used in Italy and reviewed the literature on the evolution of clear aligners based on their characteristics mentioned above by consulting the main scientific databases (PubMed, Scopus, Lilacs, Google Scholar, Cochrane Library). Inclusion and ex-clusion criteria were established. The data were collected on a purpose-made data collection form and analyzed descriptively. From the initial 580 records, 527 were excluded because they were not related to the subject of the review or because they did not meet the eligibility criteria. The remaining 31 studies were deemed comprehensive for the purpose of the review, although the “gingival margin design” feature and “auxiliaries” tool are not well represented in the more recent literature. Current knowledge on invisible aligners allows us to have a much clearer idea of the basic characteristics of aligner systems. There remains a need to deepen the use of systems other than In-visalign™ to give greater evidence to aligners that are very different based on the characteristics analyzed here and that are very widespread on the market

    L-ARGININE IN HEALTHY FOOD IN OBESE SUBJECTS WITH IMPAIRED GLUCOSE TOLERANCE AND METABOLIC SYNDROME

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    Introduction: Metabolic syndrome is characterized by impaired glucose regulation, insulin resistance, hypertension, dyslipidemia, obesity, altered indices of vascular regeneration. Nitric oxide, potent endogenous vasodilator, is synthesized by nitric oxide synthase from L-arginine. Many studies showed that L-arginine supplementation improved metabolic and vascular function. A low caloric food product containing L-arginine, in form of a biscuit, was created and used in this study. Aim: This is a 7-week, double-blind crossover study performed in obese subjects with impaired glucose tolerance and metabolic syndrome, consisting in daily consumption of 6 biscuits (enriched with L-arginine or placebo), in order to evaluate the effects of the L-arginine, on endothelial function and vascular repair. Results: In the group receiving L-arginine-enriched biscuits we found higher L-arginine, NOx and cGMP levels and post-ischemic blood flow compared with the group receiving placebo biscuits. Then L-arginine enanched both eNOS and Akt mRNA expression levels (in EPCs) and SDF-1\uf061, VEGF-\uf061, MMP-9, SCF plasmatic levels, while reduced ADMA plasmatic levels. Further we found a body weight reduction, with a significant reduction in fat mass. Conclusion: L-arginine-enriched biscuits were able to improve endothelial and vascular function, glucose metabolism, body composition, cell mobilization and differentiation properties

    Dependency structure matrix, genetic algorithms, and effective recombination

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    In many different fields, researchers are often confronted by problems arising from complex systems. Simple heuristics or even enumeration works quite well on small and easy problems; however, to efficiently solve large and difficult problems, proper decomposition is the key. In this paper, investigating and analyzing interactions between components of complex systems shed some light on problem decomposition. By recognizing three bare-bones interactions-modularity, hierarchy, and overlap, facet-wise models arc developed to dissect and inspect problem decomposition in the context of genetic algorithms. The proposed genetic algorithm design utilizes a matrix representation of an interaction graph to analyze and explicitly decompose the problem. The results from this paper should benefit research both technically and scientifically. Technically, this paper develops an automated dependency structure matrix clustering technique and utilizes it to design a model-building genetic algorithm that learns and delivers the problem structure. Scientifically, the explicit interaction model describes the problem structure very well and helps researchers gain important insights through the explicitness of the procedure.This work was sponsored by Taiwan National Science Council under grant NSC97- 2218-E-002-020-MY3, U.S. Air Force Office of Scientific Research, Air Force Material Command, USAF, under grants FA9550-06-1-0370 and FA9550-06-1-0096, U.S. National Science Foundation under CAREER grant ECS-0547013, ITR grant DMR-03-25939 at Materials Computation Center, grant ISS-02-09199 at US National Center for Supercomputing Applications, UIUC, and the Portuguese Foundation for Science and Technology under grants SFRH/BD/16980/2004 and PTDC/EIA/67776/2006

    Intraoral scanners in personal identification of corpses: usefulness and reliability of 3d technologies in modern forensic dentistry

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    Aims: This study aims to verify the applicability of modern dental technologies and their related principles of use to the forensic sciences in the field of personal identification. Background: Personal identification has always had a major role in many legal and administrative actions regarding both living and death beings. The techniques used are much less advanced than the technologies potentially available. Objective: Modern technologies, available to the daily dental clinic practice, as intraoral scanners, combined in particular to the specialist skill in orthodontics, can help redefine the methods of personal identification according to the levels of accuracy, trueness and feasibility greater than those applied in traditional forensic dentistry. Methods: 23 corpses (12F;11M) have been selected for intraoral scanning with the Carestream 3500® digital device. The superimposition of initial and late digital models, digital models and radiographs (orthopantomography and full mouth periapical films) has been evaluated to verify the stability of some structures as palatal rugae after death and to assess intraoral scanning as a successful comparative method between antemortem and postmortem records (digital models or radiographs). Obtained results were subjected to statistical analysis by the t-student test and X-square test with Yates correction (p<0.05). Results: After death, palatal rugae significatively change especially in mouths with restorations/prosthesis/missing teeth. The percentages of correct matching between scans and radiographs are very higher (up 90%; p<0.05). Conclusion: This study has been set up to study and develop new, reliable and fast methods of personal identification that can surpass many of the issues seen with the other techniques by a modern rugoscopy, a modern radiographic-digital comparison and virtual oral autopsy

    Multiple dental inclusion in monozygotic twins with congenital visual impairment

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    The study presents two monozygotic twins (MZ) with multiple impacted teeth, affecting the upper canines and lower second molars, as well as congenital aniridia. The clinical aspect of the upper canines is peculiar because of the different positions - palatal in one and buccal in the other twin. Studies reporting different scenarios of impaction in monozygotic twins can contribute more data to the debate on tooth eruption aetiology and more so in this case because of the association with a genetic panocular disease. Patients' Concerns. The patients were referred by a general dentist, who diagnosed the presence of multiple inclusions. Diagnostic Study. Both patients showed severe malocclusion, classified as grade 5 of the Index of Orthodontic Treatment Need (IOTN). The MZ showed class I malocclusion, upper and lower crowding, and impacted lower right and left second molars. A Dentascan was prescribed for the canine impaction. The impaction of the upper canine was palatal of 2.3 in one of the MZ and buccal of 1.3 in the other one. The same altered pattern of eruption of the lower second molars was identified in both twins. The proposed treatment plan contemplated orthodontic surgical recovery of the impacted elements, followed by orthodontic treatment with multibracket appliance after the extraction of the first four premolars, given the crowding entity. The use of a retraction spring action was chosen for the recovery of the lower second molars. Many aspects of the possible genetic aetiology of tooth impaction are still under discussion. The study of diseases in twins offers decisive information. Finally, the possibility that alterations in the eruptive pattern of the dental elements may be associated with other congenital problems broadens the range of investigations related to the possible aetiological causes of the inclusions in humans

    Correlation between generalised joint hypermobility and temporomandibular joint disc displacement in adolescent patients: Magnetic Resonance Imaging study

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    Aim: Temporomandibular disorders (TMD), in particular disc displacement, are recognised to have a multifactorial aetiology. Ligamentous laxity has been suggested as a potential risk factor for TMD. Ligamentous laxity can lead to generalised joint hypermobility (GJH) involving multiple joints, including the temporomandibular joint (TMJ). The aim of this work is to evaluate the correlation between GJH and disc displacement (DD) assessed on magnetic resonance images (MRI) of the TMJ in adolescent patients. Materials: The study was included 40 adolescent patients (10-16 years), divided into two groups, a Study Group (SG), composed of 20 subjects with GJH, and a Control Group (CG), composed of 20 subjects without GJH. The GJH was assessed by the Beighton test with a threshold value of ≥ 4. The severity of the TMD was determined using the Fonseca Questionnaire and a clinical evaluation of the type of TMD. The condylar-discal relationship and the condylar mobility of the TMJ were evaluated by MRI. Pearson's χ2 Test was performed for the analysis of the statistical correlation. Conclusion: This study suggests that adolescents with GJH have a greater risk of developing TMJ disc displacement, especially disc displacement without reduction
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