487 research outputs found

    Magnetic field induced non-Fermi liquid to Fermi liquid crossover at the quantum critical point of YbCu5x_{5-x}Aux_{x}

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    The temperature (T) dependence of the muon and 63^{63}Cu nuclear spin-lattice relaxation rates 1/T11/T_1 in YbCu4.4Au0.6 is reported over nearly four decades. It is shown that for T0T\to 0 1/T11/T_1 diverges following the behaviour predicted by the self-consistent renormalization (SCR) theory developed by Moriya for a ferromagnetic quantum critical point. On the other hand, the static uniform susceptibility χs\chi_s is observed to diverge as T2/3T^{-2/3} and 1/T1Tχs21/T_1T\propto \chi_s^2, a behaviour which is not accounted for by SCR theory. The application of a magnetic field HH is observed to induce a crossover to a Fermi liquid behaviour and for T0T\to 0 1/T11/T_1 is found to obey the scaling law 1/T1(H)=1/T1(0)[1+(μBH/kBT)2]11/T_1(H)= 1/T_1(0)[1+(\mu_BH/k_BT)^2]^{-1}.Comment: 4 pages, 4 figure

    A short history of anti-rheumatic therapy - VI. Rheumatoid arthritis drugs

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    The treatment of rheumatoid arthritis traditionally includes symptomatic drugs, showing a prompt action on pain and infl ammation, but without any infl uence on disease progression, and other drugs that could modify the disease course and occasionally induce clinical remission (DMARDs or disease modifying anti-rheumatic drugs). This review describes the historical steps that led to the use of the main DMARDs in rheumatoid arthritis, such as gold salts, sulphasalazine, chloroquine and hydroxychloroquine, D-penicillamine, and other immunoactive drugs, including methotrexate, azathioprine, cyclosporin and lefl unomide. The historical evolution of use of these drugs is then discussed, including the strategy of progressive ("therapeutic pyramid") or of more aggressive treatment, through the simultaneous use of two or more DMARDs ("combination therapy")

    A short history of anti-rheumatic therapy. II. Aspirin

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    The discovery of aspirin, an antipyretic, anti-inflammatory and analgesic drug, undoubtedly represents a milestone in the history of medical therapy. Since ancient times the derivatives of willow (Salix alba) were used to treat a variety of fevers and pain syndromes, although the first report dates back to 1763 when the English Reverend Edward Stone described the effect of an extract of the bark willow in treating malaria. In the XIX century many apothecaries and chemists, including the Italian Raffaele Piria and Cesare Bertagnini, developed the biological processes of extraction and chemical synthesis of salicylates, and then analyzed their therapeutic properties and pharmacokinetic and pharmacodynamic characteristics. In 1899 the Bayer Company, where Felix Hoffmann, Heinrich Dreser and Arthur Eichengrun worked, recorded acetyl-salicylic acid under the name "Aspirin". In the XX century, besides the definition of the correct applications of aspirin in the anti-rheumatic therapy being defined, Lawrence L. Crawen identified the property of this drug as an anti-platelet agent, thus opening the way for more widespread uses in cardiovascular diseases

    [Filippo Civinini (1805-1844) and the discovery of plantar neuroma].

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    Pathological abnormality (neuroma) related to the painful foot condition commonly called "Morton's metatarsalgia" was first observed in 1835 by Filippo Civinini (1805-1844) of Pistoia, in course of a cadaverous dissection, and clearly described in the anatomic letter entitled "Su un nervoso gangliare rigonfiamento alla pianta del piede" ("On the neural gangliar swelling of the foot sole"). In this study a brief review on the history of Morton's metatarsalgia is carried out, and the importance of Civinini in the discovery of the neuroma of the III intermetatarsal web is underlined

    Wars in the history of rheumatology

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    Some important discoveries in the history of rheumatology happened during war periods. It is well known that arthritis associated with conjunctivitis and urethritis, following dysenteric episodes, has been described during the First World War from the German Hans Reiter and, nearly contemporarily, from the French Noel Fiessinger and Edgar Leroy. Less known is instead the fact that the first cases of sympathetic algoneurodystrophy have been reported by the American Silas Weir Mitchell in soldiers wounded by fire-arms, during the Civil War of Secession. Other war episodes have been crucial for the development of some drugs now abundantly applied to the care of rheumatic diseases. The discovery of therapeutic effects of immunosuppressive agents, in fact, happened as an indirect consequence of the use of poison gas, already during the First World War (mustard gas), but above all after an episode in the port of Bari in 1943, where an American cargo boat was sunk. It had been loaded with a quantity of cylinders containing a nitrogenous mustard, whose diffusion in the environment provoked more than 80 deaths owing to bone marrow aplasia.Moreover, the history of the cortisone shows a strict link to the Second World War, when Germany imported large quantities of bovine adrenal glands from Argentina, with the purpose of producing some gland extracts for the Luftwasse aviators, in order to increase their performance ability

    A short history of anti-rheumatic therapy. I. An introduction on traditional and drug treatments

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    The origins of anti-rheumatic therapy are very old and mainly related to the use of traditional, sometimes extravagant, treatments, as a part of folk medicine. Spa therapy has long been used for the treatment of rheumatic diseases, as well as, in later times, physical treatments, including electrotherapy. Drug treatment has developed beginning from substances of vegetable origin, such as willow and colchicum extracts. Then it has been spread out through the chemical synthesis of compounds with specific action and therefore more effective, owing to the great development of pharmaceutical industry

    The main stages in the history of systemic lupus erythematosus

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    Systemic lupus erythematosus can be considered the most characteristic and important among the connective tissue diseases. In this short review the main stages of its history are sketched, from the introduction of the term "lupus", traditionally attributed to Roger Frugardi, in 1230 (but in fact already documented in the 10th century) to the actual knowledge of its clinical and laboratory aspects. Initially considered exclusively of dermatological interest, the first to describe a systemic form with visceral involvement were Moriz Kohn Kaposi and William Osler. Significant contribution was also given by serological diagnosis, and in particular, by the identification of specific markers of disease, such as anti-native DNA and anti-Sm antibodies, allowing early diagnosis and the establishment of an adequate therapy

    On the main stages of the history of intra-articular therapy

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    In this review the main stages in the history of intra-articular therapy of the rheumatic diseases are summarized. The first approach to such a local treatment has been likely performed in 1792 by the French physician Jean Gay, who injected in a swelling knee the "eau du Goulard" (Goulard's water), namely a mixture based on lead compounds. In the XIX century iodine derivatives have been mainly applied as an intra-articular treatment. In the XX century, before the wide use of intra-articular corticosteroids, chiefly due to the Joseph Lee Hollander's experiences, a variety of drugs has been employed, including cytostatics and sclerosing substances. A further important stage has been synoviorthesis, by using specific radionuclides, that would actually represent an anti-synovial treatment. In the last years a spread use of intra-articular hyaluronic acid, particularly in osteoarthritis, has been recorded, with the aim to warrant articular viscosupplementation. Future of intra-articular treatment should be represented by the biological drugs, i.e., anti-TNF, but it is still untimely to define the exact role of such a local treatment of arthritis

    Towards Uncovering Feature Extraction from Temporal Signals in Deep CNN: The ECG Case Study

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    Despite all the progress made in biomedical field, the Electrocardiogram (ECG) is still one of the most commonly used signal in medical examinations. Over the years, the problem of ECG classification has been approached in many different ways, most of which rely on the extraction of features from the signal in the form of temporal or morphological characteristics. Although feature engineering can led to adequately good results, it mostly relies on human ability and experience in selecting the correct feature set. In the last decade, a growing class of techniques based on Convolutional Neural Network (CNN) has been proposed in opposition to feature engineering. The efficiency and accuracy of CNN-based approaches is indisputable, however their ability in extracting and using temporal features from raw signal is poorly understood. The main objective of this work was to uncover the differences and the relationships between CNN feature maps and human-curated temporal features, towards a deeper understanding of neural-based approaches for ECG. In fact, the proposed study succeeded in finding a similarity between the output stage of the first layers of a deep 1D-CNN with several temporal features, demonstrating that not only that the engineered features effectively works in ECG classification tasks, but also that CNN can improve those features by elaborating them towards an higher level of abstraction
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