693 research outputs found

    A singular Cahn--Hilliard--Oono phase-field system with hereditary memory

    Get PDF
    We consider a phase-field system modeling phase transition phenomena, where the Cahn--Hilliard--Oono equation for the order parameter is coupled with the Coleman--Gurtin heat law for the temperature. The former suitably describes both local and nonlocal (long-ranged) interactions in the material undergoing phase-separation, while the latter takes into account thermal memory effects. We study the well-posedness and longtime behavior of the corresponding dynamical system in the history space setting, for a class of physically relevant and singular potentials. Besides, we investigate the regularization properties of the solutions and, for sufficiently smooth data, we establish the strict separation property from the pure phases

    Mathematical analysis of a phase-field model of brain cancers with chemotherapy and antiangiogenic therapy effects

    Get PDF
    Our aim in this paper is to study a mathematical model for brain cancers with chemotherapy and antiangiogenic therapy effects. We prove the existence and uniqueness of biologically relevant (nonnegative) solutions. We then address the important question of optimal treatment. More precisely, we study the problem of finding the controls that provide the optimal cytotoxic and antiangiogenic effects to treat the cancer

    From yeast killer toxins to antibiobodies and beyond

    Get PDF
    Antibiobodies are paradigmatic of yeast killer toxin (KT)-like antibodies (KAbs) mimicking the antimicrobial activity of KTs in the frame of the yeast killer phenomenon. Polyclonal, monoclonal and recombinant anti-idiotypic antibiobodies (anti-idiotypic KAbs), internal images of a wide-spectrum KT produced by the yeast Pichia anomala (PaKT), have been produced by immunization with the idiotype of a PaKT-neutralizing monoclonal antibody. Anti-idiotypic KAbs showed microbicidal activity against eukaryotic and prokaryotic pathogenic agents through the interaction with specific KT receptors (KTRs), putatively constituted by beta-glucans. Natural KAbs have been found in animals and humans experimentally or naturally infected by KTR-bearing microorganisms. Recombinant KAb-derived synthetic killer peptides showed further antiviral and immunomodulatory activities. the perspectives of KAbs and killer peptides as potential sources of novel therapeutic agents, and of KTRs and idiotypes as vaccines against infectious diseases are discussed.Istituto Superiore di SanitaUniv Parma, Sez Microbiol, Dipartimento Patol & Med Lab, I-43100 Parma, ItalyUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, Unidade Oncol Expt, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, Unidade Oncol Expt, São Paulo, BrazilWeb of Scienc

    Child abuse in a medical setting: Case illustrations of two variants of munchausen sindrome by proxy

    Get PDF
    Munchausen syndrome is a complex type of abuse, which is often underdiagnosed or misdiagnosed in clinical practice, and has harmful consequences for children. Its relationship with child abuse, of which it is a variety, must be recognized in clinical and forensic practice. The authors report herein two observed cases of different types of Münchausen syndrome by proxy (MSbP). The first, is the most severe form of MSbP, with induced, true illness and related pathological symptoms into victim. The second case is a moderate form, much more complex to detect, in which a perpetrator parent simulates and aggravates the childâs illness. Adequate training of health professionals and investigators is essential in revealing cases of MSbP. Diagnosis must be based on the study of the different forms of âabuseâ and the knowledge of clinical protocols used to validate any suspected behaviour which could be potentially harmful to the child. Moreover, a lack of training may lead to misleading interpretations of medical history interpretation and fallacious conclusions. Our study aims to review the features that are to be considered in a suspected case of MSbP, in accordance with a recently updated consensus statement by the Committee on Child Abuse and Neglect from the American Academy of Pediatrics

    Il progetto di didattica inclusiva bilingue per alunni sordi dell’Istituto Barozzi di milano: esiti di ricerca sulle competenze linguistiche degli allievi nativi segnanti

    Get PDF
    The article shows the result of a research carried on by CeDisMa, Research Center on Disability and Marginality of the Università Cattolica del Sacro Cuore, Milan, during the 2016/2017 academicyear at the Barozzi Institute of Milan which involved 20 deaf students, mainly native signers. Since the academic year 2008/2009, the school proposes a bilingual path which includes both oral language and sign based one. The deaf educator manages a LIS lab for all students involved in the project; some teachers know the LIS language while several external aids and ad hoc labs support the project. The attention is on linguistic skills achieved by the deaf students in LIS and their written text comprehension, specific attention is given to native signers.The scope is to verify the effectiveness of implementing the signed L1 and oral L2, the correlation to development and interaction as well as the improvement expectations.The article shows the result of a research carried on by CeDisMa, Research Center on Disability and Marginality of the Università Cattolica del Sacro Cuore, Milan, during the 2016/2017 academicyear at the Barozzi Institute of Milan which involved 20 deaf students, mainly native signers. Since the academic year 2008/2009, the school proposes a bilingual path which includes both oral language and sign based one. The deaf educator manages a LIS lab for all students involved in the project; some teachers know the LIS language while several external aids and ad hoc labs support the project. The attention is on linguistic skills achieved by the deaf students in LIS and their written text comprehension, specific attention is given to native signers.The scope is to verify the effectiveness of implementing the signed L1 and oral L2, the correlation to development and interaction as well as the improvement expectations

    Reduced order modeling of parametrized systems through autoencoders and SINDy approach: continuation of periodic solutions

    Full text link
    Highly accurate simulations of complex phenomena governed by partial differential equations (PDEs) typically require intrusive methods and entail expensive computational costs, which might become prohibitive when approximating steady-state solutions of PDEs for multiple combinations of control parameters and initial conditions. Therefore, constructing efficient reduced order models (ROMs) that enable accurate but fast predictions, while retaining the dynamical characteristics of the physical phenomenon as parameters vary, is of paramount importance. In this work, a data-driven, non-intrusive framework which combines ROM construction with reduced dynamics identification, is presented. Starting from a limited amount of full order solutions, the proposed approach leverages autoencoder neural networks with parametric sparse identification of nonlinear dynamics (SINDy) to construct a low-dimensional dynamical model. This model can be queried to efficiently compute full-time solutions at new parameter instances, as well as directly fed to continuation algorithms. These aim at tracking the evolution of periodic steady-state responses as functions of system parameters, avoiding the computation of the transient phase, and allowing to detect instabilities and bifurcations. Featuring an explicit and parametrized modeling of the reduced dynamics, the proposed data-driven framework presents remarkable capabilities to generalize with respect to both time and parameters. Applications to structural mechanics and fluid dynamics problems illustrate the effectiveness and accuracy of the proposed method

    Properties and limits of some essential oils: chemical characterisation, antimicrobial activity, interaction with antibiotics and cytotoxicity

    Get PDF
    Because of the emergence of multi-drug resistance bacteria and fungi, alternatives to conventional antimicrobial therapy are needed. This study aims to evaluate in vitro the antimicrobial activity of: Mirtus communis, Coriandrum sativum, Pelargonium capitatum, Cuminum cyminum, Ocimum basilicum, Citrus aurantium amara, Cymbopogon. winterianus, Cymbopogon martini, Salvia sclarea, Melaleuca alternifolia and Mentha suaveolens essential oils on bacteria and fungi, in relation to their chemical composition. The potential interaction of M. alternifolia (TTO), C. sativum (CDO) and M. suaveolens (EOMS) essential oils when used in combination with gentamicin and fluconazole has been evaluated. The results obtained showed a synergic effect on some bacteria and fungi, with FICI values ≤5. The cytotoxicity of TTO, CDO and EOMS was investigated towards HeLa cells. Only EOMS did not result cytotoxic at the active concentrations on micro-organisms. Further studies are necessary to obtain optimal ratios and dosing regimens for higher therapeutic efficacy and to decrease toxicological profiles

    Effect of Islanding and Telecontrolled Switches on Distribution System Reliability Considering Load and Green-Energy Fluctuations

    Get PDF
    To improve electrical distribution network reliability, some portions of the network could operate in autonomous mode, provided that the related technical issues are addressed. More specifically, when there is not a path from those portions to the primary substation due to a fault in the network, such portions could be disconnected from the main network and supplied by local generation only. Such a mode of operation is known as "intentional islanding" and its effectiveness, in terms of adequacy, depends on the ability of the local generation to meet the island's load. In fact, the ratio between the available local generation and load demand can frequently change during islanding due to load variations and, especially, due to the strongly irregular behavior of the primary energy sources of renewable generators. This paper proposes an analytical formulation to assess local generation adequacy during intentional islanding, accounting for the aforementioned variations. More specifically, the fluctuations of load and green-energy generators during islanding are modeled by means of Markov chains, whose output quantities are encompassed in the proposed analytical formulation. Such a formulation is used by the analytical equations of load points' outage rate and duration. The evaluation of the reliability indices accounts for a protection scheme based on an appropriate communication infrastructure. Therefore, a brief overview on the telecommunications technologies has been presented with reference to their suitability for the specific application. In particular, distribution network safety issues have been considered as the main concern. The results show that neglecting load and generation fluctuations leads to a strong overestimation of the ability of distributed generators to meet the island load. Through a case study it is observed that the error on the load point outage rate is greater than the one affecting the outage duration

    Does the natural "microcosm" created by Tuber aestivum affect soil microarthropods? A new hypothesis based on Collembola in truffle culture

    Get PDF
    microarthropods play an important role in fungi dispersion, but little is still known about the interaction between truffle and soil microarthropods. The aim of this study was to investigate the ability of the truffle Tuber aestivum to modify soil biogeochemistry (i.e. create a zone of scarce vegetation around the host plant, called a burn or brûlé) and to highlight the effects of the brûlé on the soil fauna community. We compared soil microarthropod communities found in the soil inside versus outside the T. aestivum brûlé with the chemistry of soil collected inside versus outside the brûlé. The study was carried out in three Mediterranean areas, two in Italy and one in Spain. The results confirmed the ability of T. aestivum to modify soil biogeochemistry in the brûlé: pH was higher and total organic carbon tended to be lower inside the brûlé compared to outside. Soil fauna communities showed some interesting differences. Some groups, such as Symphyla and Pauropoda, adapted well to the soil; some Collembolan families, and biodiversity and soil quality indices were generally higher outside the brûlé. Folsomia sp. showed higher abundance in the soil of the brûlé compared to outside. The results suggest that some Collembola groups may be attracted by the fungal metabolites produced by T. aestivum, while other Collembola and other microarthropods may find an unfavourable environment in the soil of the brûlé. The next steps will be to confirm this hypothesis and to extend the study to other keys groups such as nematodes and earthworms and to link fluctuations of soil communities with the biological phases of truffle growth
    • …
    corecore