3,818 research outputs found

    Slow relaxation in the Ising model on a small-world network with strong long-range interactions

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    We consider the Ising model on a small-world network, where the long-range interaction strength J2J_2 is in general different from the local interaction strength J1J_1, and examine its relaxation behaviors as well as phase transitions. As J2/J1J_2/J_1 is raised from zero, the critical temperature also increases, manifesting contributions of long-range interactions to ordering. However, it becomes saturated eventually at large values of J2/J1J_2/J_1 and the system is found to display very slow relaxation, revealing that ordering dynamics is inhibited rather than facilitated by strong long-range interactions. To circumvent this problem, we propose a modified updating algorithm in Monte Carlo simulations, assisting the system to reach equilibrium quickly.Comment: 5 pages, 5 figure

    Synthesis and biological evaluation of a trisaccharide repeating unit derivative of Streptococcus pneumoniae 19A capsular polysaccharide

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    Streptococcus pneumoniae (SP) is a common human pathogen associated with a broad spectrum of diseases and it is still a leading cause of mortality and morbidity worldwide, especially in children. Moreover, SP is increasingly associated with drug resistance. Vaccination against the pathogen may thus represent an important strategy to overcome its threats to human health. In this context, revealing the molecular determinants of SP immunoreactivity may be relevant for the development of novel molecules with therapeutic perspectives as vaccine components. Serogroup 19 comprises the immune-cross reactive types 19F, 19A, 19B and 19C and it accounts for a high percentage of invasive pneumococcal diseases, mainly caused by serotypes 19F and 19A. Herein, we report the synthesis and biological evaluation of an aminopropyl derivative of the trisaccharide repeating unit of SP 19A. We compare two different synthetic strategies, based on different disconnections between the three monosaccharides which make up the final trisaccharide, to define the best approach for the preparation of the trisaccharide. Synthetic accessibility to the trisaccharide repeating unit lays the basis for the development of more complex biopolymer as well as saccharide conjugates. We also evaluate the binding affinity of the trisaccharide for anti-19A and anti-19F sera and discuss the relationship between the chemical properties of the trisaccharide unit and biological activity

    The third KV62 radar scan: Searching for hidden chambers adjacent to Tutankhamun's tomb

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    The existence of hidden chambers and corridors adjacent to Tutankhamun’s tomb (code name KV62) hasbeen long debated. In 2015 it was suggested that these chambers may host the as yet undiscovered burialof Nefertiti. In order to test this hypothesis, two Ground Penetrating Radar (GPR) surveys, conductedin 2015 and 2016 from inside KV62, were carried out, but gave contradictory results. To solve theseuncertainties and obtain a more confident and conclusive response, a third GPR survey was conductedby our team in February 2018. The results of this third radar scan are reported in this article. Three GPRsystems with multiple frequency bands (from 150 MHz to 3000 MHz) and very dense spatial samplingwere adopted. After careful data processing, no evidence of marked discontinuities due to the passagefrom natural rock to artificial blocking walls were found in the radargrams. It is therefore concluded thatthere are no hidden chambers immediately adjacent to the Tomb of Tutankhamun

    SUMMER SORES SECONDARY TO A HOOF CRACK IN AN ANDALUSIAN STALLION

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    Cutaneous habronemosis in horses is caused by larvae of the spirurid nematodes Habronema microstoma and Habronema muscae. These lesions, also known as "summer sores'', are often severe and disfiguring. Although Habronema-caused lesions at the coronary grooves have been described, cases of hoof cracks with secondary summer sores have never been reported. The present case describes clinic-pathological and surgical features of a quarter crack case complicated by cutaneous habronemosis at the dermal layers. A 15-year-old, Andalusian stallion was referred to the Veterinary Teaching Hospital of the University of Teramo because of a mass of the hoof and a severe lameness. The clinical examination revealed an exuberant granulation tissue protruding from a full thickness vertical quarter crack. The mass was surgically removed, and subjected to histopathological, microbiological, and parasitological analyses. A copromicroscopic examination was also performed. The feces scored PCR positive for H. muscae, while the skin for both H. microstoma and H. muscae, thus confirming the primary role of Habronema in causing the hoof mass. This is the first description of a hoof wall crack complicated by summer sores, with simultaneous gastric habronemosis. This case confirms that a prompt diagnosis during fly activity is imperative for an efficacious treatment and a timely prevention of disfiguring summer sores

    Perspectives on alternatives to phthalate plasticized poly(vinyl chloride) in medical devices applications

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    Poly(vinyl chloride) (PVC) is one of the most important polymeric materials available today and is used to manufacture many items, ranging from packaging and toys to healthcare devices. PVC is per se a rigid material but it is made softer by compounding with plasticizers, particularly phthalate esters such as di-(2-ethylhexyl) phthalate (DEHP). In flexible plasticizer PVC (P-PVC), phthalates are not chemically bound to PVC and they are released into the external environment. In particular, prolonged contact of P-PVC based medical devices with body fluids or tissues has been shown to be associated with severe health risks. Major concerns regarding the safety of P-PVC in medical plastic items have been raised, and several alternatives to phthalates and to P-PVC itself as well as chemical/physical treatments of P-PVC to reduce DEHP migration have been proposed. This review outlines recent scientific approaches for preventing DEHP contamination of humans by P-PVC medical devices, highlighting the impact of the proposed alternative materials on human health and strategies for implementing them

    FMECA methodology applied to two pathways in an orthopaedic hospital in Milan.

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    INTRODUCTION: Adverse events pose a challenge to medical management: they can produce mild or transient disabilities or lead to permanent disabilities or even death; preventable adverse events result from error or equipment failure. METHODS: IRCCS Istituto Ortopedico Galeazzi implemented a clinical risk management program in order to study the epidemiology of adverse events and to improve new pathways for preventing clinical errors: a risk management FMECA-FMEA pro-active analysis was applied either to an existing clinical support pathway or to a new process before its implementation. RESULTS: The application of FMEA-FMECA allowed the clinical risk unit of our hospital to undertake corrective actions in order to reduce the adverse events and errors on high-risk procedure used inside the hospitals

    Landslide mapping and characterization through Infrared Thermography (IRT): Suggestions for a methodological approach from some case studies

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    In this paper, the potential of Infrared Thermography (IRT) as a novel operational tool for landslide surveying, mapping and characterization was tested and demonstrated in different case studies, by analyzing various types of instability processes (rock slide/fall, roto-translational slide-flow). In particular, IRT was applied, both from terrestrial and airborne platforms, in an integrated methodology with other geomatcs methods, such as terrestrial laser scanning (TLS) and global positioning systems (GPS), for the detection and mapping of landslides’ potentially hazardous structural and morphological features (structural discontinuities and open fractures, scarps, seepage and moisture zones, landslide drainage network and ponds). Depending on the study areas’ hazard context, the collected remotely sensed data were validated through field inspections, with the purpose of studying and verifying the causes of mass movements. The challenge of this work is to go beyond the current state of the art of IRT in landslide studies, with the aim of improving and extending the investigative capacity of the analyzed technique, in the framework of a growing demand for effective Civil Protection procedures in landslide geo-hydrological disaster managing activities. The proposed methodology proved to be an effective tool for landslide analysis, especially in the field of emergency management, when it is often necessary to gather all the required information in dangerous environments as fast as possible, to be used for the planning of mitigation measures and the evaluation of hazardous scenarios. Advantages and limitations of the proposed method in the field of the explored applications were evaluated, as well as general operative recommendations and future perspectives
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