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This paper deals with the mathematical modelling of crowd dynamics within the framework of continuum mechanics. The method uses the mass conservation equation closed by phenomenological models linking the local velocity to density and density gradients. The closures take into account movement in more than one space dimension, presence of obstacles, pedestrian strategies, and modelling of panic conditions. Numerical simulations of the initial-boundary value problems visualize the ability of the models to predict several interesting phenomena related to the complex system under consideration. [ABSTRACT FROM AUTHOR]

This review reports the existing literature on traffic flow modelling in the framework of a critical overview which aims to indicate research perspectives. The contents mainly refer to modelling by fluid dynamic and kinetic equations and are arranged in three parts. The first part refers to methodological aspects of mathematical modelling and to the interpretation of experimental results. The second part is devoted to modelling and deals both with methodological aspects and with the description of some specific models. The third part reports about an overview on applications and research perspectives. [ABSTRACT FROM AUTHOR]

Steady, fully developed flows of second order fluids in curved pipes of circular crosssection have previously been studied using regular perturbation methods. These perturbation solutions are applicable for pipes with small curvature ratio: The cross sectional radius of the pipe divided by the radius of curvature of the pipe centerline. It was shown by Jitchote and Robertson that perturbation equations could be illposed when the second normal stress coefficient is nonzero. Motivated by the singular nature of the perturbation equations, here, we study the full governing equations without introducing assumptions inherent in perturbation methods. In particular, we examine the existence and uniqueness of solutions to the full governing equations for second order fluids. We show rigorously that a solution to the full problem exists and is locally unique for small non-dimensional pressure drop, in agreement with earlier results obtained using a formal expansion in the curvature ratio. The results obtained here are valid for arbitrarily shaped cross-section (sufficiently smooth) and for all curvature ratios. An operator splitting method has been employed which may be useful for numerical studies of steady and unsteady flows of second order fluids in curved pipes. [ABSTRACT FROM AUTHOR]

Cryoablation of slow pathway doesn't usually cause junctional beats. If this occurs, the nearness to AV compact node is supposed. 3d electroanatomical mapping during this unusual finding may help to clarify the relationship between junctional beats (JBs) during cryomapping/cryoablation and Koch's triangle., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)

Background: Orthostatic hypotension (OH) has high prevalence in frail older adults. However, its effect on mortality, disability, and hospitalization in frail older adults is poorly investigated. Thus, we assessed the relationship between the prevalence of OH and its effect on mortality, disability, and hospitalization in noninstitutionalized older adults stratified by frailty degree., Methods: Prospective, observational study of 510 older participants (≥65 years of age) consecutively admitted to a geriatric evaluation unit to perform a geriatric comprehensive assessment., Measurements: Clinical frailty was assessed using the Italian frailty index (40 items). Systolic blood pressure (mm Hg), diastolic blood pressure (mm Hg), and heart rate (bpm) were evaluated in clinostatic position and after 1, 3, and 5 minutes of orthostatic position. OH was defined with a decrease of 20 mm Hg in systolic blood pressure and/or a decrease of 10 mm Hg in diastolic blood pressure., Results: OH prevalence was 22%, and it increased from 9.0% to 66.0% according to frailty degree (P for trend <.001). When stratified by frailty degree, mortality, disability, and hospitalization increased from 1.0% to 24.5%, from 39.0% to 77.0% and from 14.0% to 32.0% in the absence, and from 0.0% to 35.5%, from 42.0% to 95.5% and from 19.0% to 65.5% in the presence of OH, respectively (P < .01 vs absence of OH). Multivariate analysis showed that the Italian frailty index is more predictive of mortality, disability, and hospitalization in the presence than in the absence of OH., Conclusions: OH is a common condition in frail older adults, and it is strongly associated with mortality, disability, and hospitalization in the highest frailty degree. Thus, OH may represent a new marker of clinical frailty., (Copyright © 2018 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.)

Background: The onset of bruising in surgery is a frequent event that can be a source of complications and delays in the patient's healing process (pigmentations, fibrosis, etc.). Having the help of an effective topical product that speeds up the resorption of blood extravasation can be an advantage in phlebological surgery and surgery in general., Methods: Twenty-three patients both male and female (age range: 30-72 years) were enrolled. Twenty-two of them completed the study, all underwent venous surgery of the lower extremities (invagination stripping of the internal or external saphenous and Muller's ambulatory phlebectomy). The 22 patients were divided into 2 groups of 11 each and in a single blind study received topical daily therapy (every 12 hours) either in the form of a medication cream (active ingredient), or a placebo cream. All patients wore compression one-leg tights immediately after surgery, following measurement of the lower limb (Struva® 35 mmHg, Medi Italia, Zola Predosa, Bologna, Italy). The 30-day observational study was carried out using a standard photographic survey procedure., Results: The topical application of polysulfated galactosaminoglycan showed a significantly higher rate of resorption of blood extravasations than in patients in the single blind study receiving topical therapy with the placebo (Fisher's Exact Test, dichotomous variable outcome, N.=22, with result P=0.0001<0.05)., Conclusions: Topical therapy with a mixture of polysulfated galactosaminoglycans provides valid protection in the therapy of blood extravasations in phlebology and general surgery.

Background: Absorbable sutures are not generally accepted by most vascular surgeons for the fear of breakage of the suture line and the risk of aneurysmal formation, except in cases of paediatric surgery or in case of infections. Aim of this study is to provide evidence of safety and efficacy of the use of absorbable suture materials in carotid surgery., Patients and Methods: In an 11 year period, 1126 patients (659 male [58.5%], 467 female [41.5%], median age 72) underwent carotid endarterectomy for carotid stenosis by either conventional with primary closure (cCEA) or eversion (eCEA) techniques. Patients were randomised into two groups according to the type of suture material used. In Group A, absorbable suture material (polyglycolic acid) was used and in Group B non-absorbable suture material (polypropylene) was used. Primary end-point was to compare severe restenosis and aneurysmal formation rates between the two groups of patients. For statistical analysis only cases with a minimum period of follow-up of 12 months were considered., Results: A total of 868 surgical procedures were considered for data analysis. Median follow-up was 6 years (range 1-10 years). The rate of postoperative complications was better for group A for both cCEA and eCEA procedures: 3.5% and 2.0% for group A, respectively, and 11.8% and 12.9% for group B, respectively., Conclusions: In carotid surgery, the use of absorbable suture material seems to be safe and effective and with a general lower complications rate compared to the use of non-absorbable materials.

Purpose: This study used cone-beam computed tomography to evaluate morphologic changes of the mandibular anterior ridge after using augmented corticotomy plus accelerated orthodontia to decompensate mandibular incisors in patients with surgical skeletal Class III., Materials and Methods: Fourteen patients (8 men, 6 women; mean age, 26.14 yr) with skeletal Class III were treated before orthognathic surgery with a technique that combined corticotomy, bone grafting, and accelerated orthodontic forces to decompensate the lower incisors. Three-dimensional cone-beam computed tomograms were taken before treatment (T0) and at the completion of presurgical orthodontic treatment (T1). Measurements of the amount of vertical alveolar bone changes and horizontal bone thickness at the midroot and root apex levels of the mandibular incisors were evaluated., Results: All patients showed significant proclination of the mandibular incisors at T1. The mean alveolar bone thickness from T0 to T1 increased buccally at the midroot and apex levels, showing statistically significant horizontal bone augmentation at the labial side of the lower anterior mandibular teeth (P < .05). The mean amount of vertical bone change did not show any significant vertical loss of alveolar bone., Conclusion: This new combined technique provided adequate decompensation of the mandibular incisors by increasing horizontal bone thickness in the labial aspect of the mandibular anterior area, without any vertical bone loss. This approach decreases the risk of the typical periodontal complications associated with traditional orthodontics, such as marginal bone loss and gingival recession., (Copyright © 2013 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)