159 research outputs found

    Current laboratory diagnostics of coronavirus disease 2019 (COVID-19)

    Get PDF
    Laboratory medicine provides an almost irreplaceable contribution to the diagnostic reasoning and managed care of most human pathologies. The novel coronavirus disease 2019 (COVID-19) is not an exception to this paradigm. Although the relatively recent emergence does not allow to draw definitive conclusions on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnostics, some standpoints can be conveyed. First and foremost, it seems now clear that we will be living together with this virus for quite a long time, so that our vigilance and responsiveness against the emergence of new local outbreaks shall be maintained at the highest possible levels. The etiological diagnosis of COVID-19 is, and will remain for the foreseeable future, deeply based on direct identification of viral RNA by means of molecular biology techniques in biological materials, especially upper and lower respiratory tract specimens. Whether other materials, such as blood, urine, stools, saliva and throat washing, will become valid alternatives has not been unequivocally defined so far. As concerns serological testing, promising information can be garnered from preliminary investigations, showing that the vast majority of COVID-19 patients seem to develop a sustained immune response against the virus, characterized especially by emergence of anti-SARS-CoV-2 IgG and IgA, 1 to 2 weeks after the onset of fever and/or respiratory symptoms. Whether these antibodies will have persistent neutralizing activity against the virus is still to be elucidated on individual and general basis. The availability of rapid tests for detecting either viral antigens or anti-SARS-CoV-2 antibodies are a potentially viable opportunity for purposes of epidemiologic surveillance, though more information is needed on accuracy and reliability of these portable immunoassays

    Interfering resonances in a quantum billiard

    Full text link
    We present a method for numerically obtaining the positions, widths and wavefunctions of resonance states in a two dimensional billiard connected to a waveguide. For a rectangular billiard, we study the dynamics of three resonance poles lying separated from the other ones. As a function of increasing coupling strength between the waveguide and the billiard two of the states become trapped while the width of the third one continues to increase for all coupling strengths. This behavior of the resonance poles is reflected in the time delay function which can be studied experimentally.Comment: 2 pages, 3 figure

    Angular momentum dependence of the GDR width in Sn nuclei at fixed excitation energy

    Get PDF
    Abstract High-energy Îł-rays from the decay of the giant-dipole resonance (GDR) in the hot 106Sn compound nucleus and its daughters were measured in coincidence with heavy recoiling evaporation residues. The compound nucleus was formed at excitation energy E ∗ = 80 MeV using the reaction 56Ni+48Ti at a bombarding energy of 260 MeV. The analysis yields the GDR width for two different intervals of angular momentum 〈J〉 = 24 and 36ℏ. The present data, combined with previous data at higher angular momentum permit a study of the angular momentum dependence of the GDR width for 10 â©œ J â©œ 60ℏ at approximately fixed temperature. The width of the GDR is found to be roughly constant for

    Possible Conservation of the K -Quantum Number in Excited Rotating Nuclei

    Get PDF
    The \ensuremath{\gamma} cascades feeding into low-K and high-K bands in 163{}^{163}Er are investigated analyzing variances and covariance of the spectrum fluctuations. From a large data set of 109{0}^{9} triple coincidences, \ensuremath{\gamma}-\ensuremath{\gamma} coincidence spectra gated by resolved low-lying rotational bands are analyzed. Low-K bands are found to be fed by a much larger effective number of cascades than high-K bands. The covariance between pairs of gated spectra shows that the cascades feeding low-K bands are different from those feeding the high-K bands. The persistence of the K-selection rules for the excited rotational bands within the angular momentum region 30\ensuremath{\Elzxh}\ensuremath{\le}I\ensuremath{\le}40\ensuremath{\Elzxh} is suggested as explanation

    GDR in Superdeformed Nuclei

    Get PDF
    A search for the gamma decay of the Giant Dipole Resonance built on superdeformed nuclear configurations was made. The superdeformed states of the Eu-143 nucleus were populated using the reaction Pd-110(Cl-37, 4n)Eu-143 at a beam energy of 165 MeV. High energy gamma-rays were detected in 8 large BaF2 scintillators in coincidence with discrete transitions measured with part of the NORDBALL array (17 HPGe detectors and a 2 pi multiplicity filter). Spectra of high-energy gamma-rays gated by low-energy transitions from states fed by the superdeformed bands show an excess yield in the 7-10 MeV region with respect to those gated by transitions from states not populated by the superdeformed bands. Because the dipole oscillation along the superdeformed axis of the nucleus is expected to have a frequency corresponding to approximate to 8 MeV (low energy component of the GDR strength function), the present result gives the first experimental indication of gamma-ray emission of the GDR built on a superdeformed states

    The damping width of giant dipole resonances of cold and hot nuclei: a macroscopic model

    Get PDF
    A phenomenological macroscopic model of the Giant Dipole Resonance (GDR) damping width of cold- and hot-nuclei with ground-state spherical and near-spherical shapes is developed. The model is based on a generalized Fermi Liquid model which takes into account the nuclear surface dynamics. The temperature dependence of the GDR damping width is accounted for in terms of surface- and volume-components. Parameter-free expressions for the damping width and the effective deformation are obtained. The model is validated with GDR measurements of the following nuclides, 39,40^{39,40}K, 42^{42}Ca, 45^{45}Sc, 59,63^{59,63}Cu, 109−120^{109-120}Sn,147^{147}Eu, 194^{194}Hg, and 208^{208}Pb, and is compared with the predictions of other models.Comment: 10 pages, 5 figure

    Scaling Properties of the Giant Dipole Resonance Width in Hot Rotating nuclei

    Get PDF
    We study the systematics of the giant dipole resonance width Γ\Gamma in hot rotating nuclei as a function of temperature TT, spin JJ and mass AA. We compare available experimental results with theoretical calculations that include thermal shape fluctuations in nuclei ranging from A=45 to A=208. Using the appropriate scaled variables, we find a simple phenomenological function Γ(A,T,J)\Gamma(A,T,J) which approximates the global behavior of the giant dipole resonance width in the liquid drop model. We reanalyze recent experimental and theoretical results for the resonance width in Sn isotopes and 208^{208}Pb.Comment: LaTeX, 4 pages with 4 figures (to appear in Phys. Rev. Lett.

    Compilation of Giant Electric Dipole Resonances Built on Excited States

    Get PDF
    Giant Electric Dipole Resonance (GDR) parameters for gamma decay to excited states with finite spin and temperature are compiled. Over 100 original works have been reviewed and from some 70 of which more than 300 parameter sets of hot GDR parameters for different isotopes, excitation energies, and spin regions have been extracted. All parameter sets have been brought onto a common footing by calculating the equivalent Lorentzian parameters. The current compilation is complementary to an earlier compilation by Samuel S. Dietrich and Barry L. Berman (At. Data Nucl. Data Tables 38(1988)199-338) on ground-state photo-neutron and photo-absorption cross sections and their Lorentzian parameters. A comparison of the two may help shed light on the evolution of GDR parameters with temperature and spin. The present compilation is current as of January 2006.Comment: 31 pages including 1 tabl

    Proposta di una “checklist” per il prelievo di sangue venoso

    Get PDF
    The collection of venous blood is central in clinical laboratory activity. Although there is widespread perception that this practice is simple and free of complications and side effects, it is undeniable that the vast majority of laboratory errors arises from ignorance, incompetence or negligence during venipuncture. It has hence become advisable to prepare a document in simplified form of checklist, consisting of a concise but comprehensive list of activities to be completed or verified in order to prevent errors during venous blood collection. In the intention of authors, this synthetic checklist is a modular tool, adaptable to different local contexts, it can be easily and gradually implemented, it is supported by scientific evidence and consensus of experts and created with the support of different healthcare professionals and it is adherent to the best practices and requires minimal resources for implementation. It is reasonable to assume that this checklist may be able to withstand system and individual changes, strengthening the standards for safety of both operators and patients, limiting potential failure patterns. We hope that the checklist may be implemented in all healthcare facilities where routine venous blood collection is performed, after adaptation to suit characteristics of local organization

    Immunological resilience and biodiversity for prevention of allergic diseases and asthma

    Get PDF
    Increase of allergic conditions has occurred at the same pace with the Great Acceleration, which stands for the rapid growth rate of human activities upon earth from 1950s. Changes of environment and lifestyle along with escalating urbanization are acknowledged as the main underlying causes. Secondary (tertiary) prevention for better disease control has advanced considerably with innovations for oral immunotherapy and effective treatment of inflammation with corticosteroids, calcineurin inhibitors, and biological medications. Patients are less disabled than before. However, primary prevention has remained a dilemma. Factors predicting allergy and asthma risk have proven complex: Risk factors increase the risk, while protective factors counteract them. Interaction of human body with environmental biodiversity with micro-organisms and biogenic compounds as well as the central role of epigenetic adaptation in immune homeostasis have given new insight. Allergic diseases are good indicators of the twisted relation to environment. In various non-communicable diseases, the protective mode of the immune system indicates low-grade inflammation without apparent cause. Giving microbes, pro- and prebiotics, has shown some promise in prevention and treatment. The real-world public health programme in Finland (2008-2018) emphasized nature relatedness and protective factors for immunological resilience, instead of avoidance. The nationwide action mitigated the allergy burden, but in the lack of controls, primary preventive effect remains to be proven. The first results of controlled biodiversity interventions are promising. In the fast urbanizing world, new approaches are called for allergy prevention, which also has a major cost saving potential.Peer reviewe
    • 

    corecore