Better and faster solutions for the maximum diversity problem

The aim of the Maximum Diversity Problem (MDP) is to extract a subset M of given cardinality from a set of elements N, in such a way that the sum of the pairwise distances between the elements of M is maximum. This problem, introduced by Glover [7], has been deeply studied using GRASP methodologies [6, 1, 17, 2, 16]. Usually, effective algorithms owe their success more to the careful exploitation of problem-specific features than to the application of general-purpose methods. A solution for MDP has a very simple structure which can not be exploited for sophisticated neighborhood search. This paper explores the performance of three alternative solution approaches, that is Tabu Search, Variable Neighborhood Search and Scatter Search, comparing them with those of best GRASP algorithms in literature. We also focus our attention on the comparison of these three methods applied in their pure form

Humeral greater tuberosity osteolysis as a complication of intraosseous calcification migration: Natural history depicted by imaging

Migration of calcification within the bone leading to greater tuberosity osteolysis is a peculiar complication of the calcifying tendinitis of the rotator cuff. The case of a 38-year-old woman complaining of right shoulder pain, which had been going on for one year, is hereby described. The evolution of the infraspinatus tendon calcifying tendinitis leading to osteolysis of the greater tuberosity of the humerus is depicted by imaging and, particularly, by the MR and CT features changing over time. In this paper we focus on the importance of both MR and CT exams in the diagnostic process of the different phases of the disease. The correlation between clinical symptoms and imaging features is also helpful for imaging interpretation: the most painful phase corresponds to the migration of the calcification, whereas pain tends to decrease when the osteolysis develops. Awareness of the existence of this condition may prevent unnecessary invasive procedures. (www.actabiomedica.it)

Basic knowledge and new advances in panoramic radiography imaging techniques: A narrative review on what dentists and radiologists should know

Objectives: A panoramic radiograph (PAN) is the most frequently diagnostic imaging technique carried out in dentistry and oral surgery. The correct performance of image acquisition is crucial to obtain adequate image quality. The aim of the present study is to (i) review the principles of PAN image acquisition and (ii) describe positioning errors and artefacts that may affect PAN image quality. Methods: Articles regarding PAN acquisition principles, patient’s positioning errors, artefacts, and image quality were retrieved from the literature. Results: Head orientation is of the utmost importance in guaranteeing correct image acquisition. Symmetry, occlusal plane inclination, mandibular condyles localization, cervical spine position, aspect of upper teeth root apexes, exposure parameters, and metal and motion artefacts are factors that greatly affect the image quality of a successful PAN. Conclusions: Several factors are the basis for PAN performance; therefore, a systematic approach that takes into account correct patient positioning and preparation is strongly suggested to improve overall examination quality

Ambulance location through optimization and simulation : the case of Milano urban area

In this paper, the problem of locating ambulance posts over an urban area is considered. A three steps approach is presented to deal with this problem, that combines different skills. First, the real life data on the considered system behavior are analyzed. Then, integer linear programming models are considered with the aim of finding new post locations. As such models represent a simplification and an abstraction with respect to the real life situation, the behavior of the proposed solutions is tested with a simulation framework, tailored on the considered problem features. The whole approach is tested over the Milano city area case, with the aim of pointing out the criticality of the system and providing suggestions for the emergency service management. Computational results are presented and discussed

Ultra-High Frequency Ultrasound (Uhfus) Applications in Sjogren Syndrome: Narrative Review and Current Concepts

Primary Sjogren’s syndrome (SS) is a systemic autoimmune chronic inflammatory disease with predominant involvement of the exocrine glands, particularly the salivary glands (SGs). The role of salivary glands ultrasound (SGUS) in the work-up of patients with primary Sjogren syndrome (SS) is progressively increasing due to its useful support in diagnosis and follow-up as a widely available, repeatable, noninvasive and safe technique. Although SGUS is not yet included in the dominant primary SS classification, several studies supported its inclusion in the American College of Rheumatology/European League Against Rheumatism criteria. In this context, a novel imaging technique, ultra-high frequency ultrasound (UHFUS), is being explored. Compared to the frequencies used in conventional ultrasound (US) (up to 22 MHz), UHFUS operates with higher frequencies (30–100 MHz) allowing for outstanding image resolution, up to 30 μm. UHFUS permits the scn of both major and minor SGs, opening new avenues for the integration of tissue and imaging biomarkers. Although further studies are needed to confirm its role, this novel imaging technique might lead to several potential improvements, including earlier diagnosis, reduction of unnecessary and inadequate biopsies and better management and follow-up of patients with primary SS