908 research outputs found

    Phase transitions of extended-range probabilistic cellular automata with two absorbing states

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    We study phase transitions in a long-range one-dimensional cellular automaton with two symmetric absorbing states. It includes and extends several other models, like the Ising and Domany-Kinzel ones. It is characterized by a competing ferromagnetic linear coupling and an antiferromagnetic nonlinear one. Despite its simplicity, this model exhibits an extremely rich phase diagram. We present numerical results and mean-field approximations.Comment: New and expanded versio

    A case report of chondrocalcinosis of the temporomandibular joint: Surgical management and literature review

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    Background: Chondrocalcinosis is a metabolic disorder characterized by non-infectious joint inflammation with intra- or periarticular calcification. Temporomandibular (TMJ) chondrocalcinosis is rare and not usually included in the differential diagnosis of TMJ and facial pain disorders. Case report: A 67-year-old woman presented with a calcified mass in the right TMJ between the condyle and glenoid fossa, eroding into the floor of the middle cranial fossa due to calcium pyrophosphate deposition in the TMJ. She underwent surgical excision of the mass with immediate econstruction with a custom-made prosthesis. On follow-up, there was complete clinical resolution, with no evidence of recurrence. Literature related to surgical treatment of chondrocalcinosis of TMJ and its treatment was reviewed. Surgery is the most commonly used treatment. A custom-made device allowed us to bridge the defect caused by the destructive disease process. Conclusion: Custom-made prostheses can be considered a safe and effective solution in erosive forms of chondrocalcinosis, replacing the TMJ to restore functionality and correct the anatomical defect

    Double osseous flaps for simultaneous midfacial and mandible reconstruction: Automation in surgical complexity within an entirely computerized workflow

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    Introduction: Broad maxillofacial surgical resections involving both the midface and the mandible represent a challenge in terms of reconstruction. Although several papers have explored the possibility of simultaneously using two microsurgical flaps, reports on the implementation of a dual osseous flap strategy are limited, and mainly addressed to static anatomical reconstruction, regardless of functional implications. In particular, there is a lack in the literature of a unifying protocol which illustrates how technology including virtual planning, statistical shape modeling, virtual occlusion, 3D-printing and patient-specific implants can address the functional and accuracy needs required for an optimal reconstruction. Materials and methods: In this paper, the Authors present their preliminary experience in a two-center study, showing how broad maxillofacial defects, requiring a simultaneous reconstruction in both the mandible and the midface, can be successfully reconstructed using the combination of two osseous flaps in an automated sequence in which all steps are anticipately defined in a virtual plan, accounting for the optimal alignment of temporomandibular joint, predicting the final occlusion and defining a mandibular shape according to a statistical shape model. Results: Average RMSE for the iliac bone crest flap was of 3.2 ± 0.36 mm; for the fibula flap, RMSE value was of 2.3 ± 0.65 mm, for patient-specific implants, for mandibular prostheses the average RMSE was 2.46 mm with 0.76 mm standard deviation. Temporomandibular joint function increased when a TMJ prosthesis was placed. Conclusions: Double bone free flap is a valuable resource to reconstruct wide defects that simultaneously involve two thirds of the cranio-maxillo-facial skeleton, but a careful virtual planning study should be always performed before approaching this surgical option

    Quantum and classical echoes in scattering systems described by simple Smale horseshoes

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    We explore the quantum scattering of systems classically described by binary and other low order Smale horseshoes, in a stage of development where the stable island associated with the inner periodic orbit is large, but chaos around this island is well developed. For short incoming pulses we find periodic echoes modulating an exponential decay over many periods. The period is directly related to the development stage of the horseshoe. We exemplify our studies with a one-dimensional system periodically kicked in time and we mention possible experiments.Comment: 7 pages with 6 reduced quality figures! Please contact the authors ([email protected]) for an original good quality pre-prin

    The Transantral Endoscopic Approach: A Portal for Masses of the Inferior Orbit\u2014Improving Surgeons' Experience Through Virtual Endoscopy and Augmented Reality

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    In the past years, endoscopic techniques have raised an increasing interest to perform minimally invasive accesses to the orbit, resulting in excellent clinical outcomes with inferior morbidities and complication rates. Among endoscopic approaches, the transantral endoscopic approach allows us to create a portal to the orbital floor, representing the most straightforward access to lesions located in the inferior orbital space. However, if endoscopic surgery provides enhanced magnified vision of the anatomy in a bloodless field, then it has several impairments compared with classic open surgery, owing to restricted operative spaces. Virtual surgical planning and anatomical computer-generated models have proved to be of great importance to plan endoscopic surgical approaches, and their role can be widened with the integration of surgical navigation, virtual endoscopy simulation, and augmented reality (AR). This study focuses on the strict conjugation between the technologies that allow the virtualization of surgery in an entirely digital environment, which can be transferred to the patient using intraoperative navigation or to a printed model using AR for pre-surgical analysis. Therefore, the interaction between different software packages and platforms offers a highly predictive preview of the surgical scenario, contributing to increasing orientation, awareness, and effectiveness of maneuvers performed under endoscopic guidance, which can be checked at any time using surgical navigation. In this paper, the authors explore the transantral approach for the excision of masses of the inferior orbital compartment through modern technology. The authors apply this technique for masses located in the inferior orbit and share their clinical results, describing why technological innovation, and, in particular, computer planning, virtual endoscopy, navigation, and AR can contribute to empowering minimally invasive orbital surgery, at the same time offering a valuable and indispensable tool for pre-surgical analysis and training

    The Impact of COVID-19 on Plastic Surgery Residency Training

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    Abstract: Nowadays didactic and surgical activities for residents in the surgery field are less and less due to an increasing burden of documentation and \u201cnon-educational work.\u201d Considering the current lockdown due to the COVID-19 pandemic, it has never been so important to find different ways to allow residents to improve their knowledge. We asked all plastic and esthetic surgery residents in our country to fill out a questionnaire to investigate changes in their didactical activity and analyze problems about their professional growth in the last few months. From the results of such questionnaires, we found that most of the residents feel the decrease in surgical activities during this time is a detrimental factor for their training and that even if all the schools have changed their didactical activities no school has introduced the use of virtual simulators to compensate for the decrease in surgical practice. Actually, the majority of residents use webinars to keep updated, stating that such technologies are useful but not sufficient to analyze plastic surgery topics in depth during COVID-19 lockdown. Virtual interactive tools are well known in different clinical and surgical specialties, and they are considered as a valid support, but it seems that in plastic surgery they are not so used. According to the most recent studies about residents\u2019 didactical program, we have investigated the potential of Anatomage Table in combination with Touch Surgery application as physical and mental aids to bypass the decreased number and kind of surgical interventions performed in this particular time. Anatomage is an academic user-friendly touch screen table; it is used by both medical students and residents to learn human anatomy and to master surgical anatomy. Touch Surgery is an application available on smartphones and tablets that gives the possibility to watch real and virtually designed surgical videos, accompanied by explanatory comments on the surgical phases; they are interactive and give the possibility to check what you have learned through tests administered after virtual classes. In our opinion, these tools represent reliable solutions to improve plastic residents\u2019 training, mostly during the COVID-19 pandemic. Level of Evidence V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266
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