112 research outputs found
Low-light-level nonlinear optics with slow light
Electromagnetically induced transparency in an optically thick, cold medium
creates a unique system where pulse-propagation velocities may be orders of
magnitude less than and optical nonlinearities become exceedingly large. As
a result, nonlinear processes may be efficient at low-light levels. Using an
atomic system with three, independent channels, we demonstrate a quantum
interference switch where a laser pulse with an energy density of
photons per causes a 1/e absorption of a second pulse.Comment: to be published in PR
On the path to rabies elimination: The need for risk assessments to improve administration of post-exposure prophylaxis.
Costs of rabies post-exposure prophylaxis (PEP) often remain high in regions where rabies has been controlled in dogs, presenting a challenge for sustaining rabies elimination programmes. We investigated the potential for bite patient risk assessments to improve PEP provision and surveillance in settings approaching elimination of dog-mediated rabies. We conducted a longitudinal study of patients presenting to animal bite treatment centres (ABTCs) on the island province of Bohol in the Philippines to investigate the health status of biting dogs and to quantify current expenditure on PEP. Incidence of bite patients presenting to ABTCs was high (>300/100,000 persons/year) and increasing, resulting in substantial health provider costs. Over $142,000 was spent on PEP in 2013 for a population of 1.3 million. From follow up of 3820 bite patients we found thatâŻÂ >92% were bitten by healthy dogs (alive 14âŻdays after the bite) and just 1.4% were bitten by probable or confirmed rabid dogs. The status of dogs that bit 6% of patients could not be determined. During the course of investigations of bites by suspect dogs, we were able to obtain samples for case confirmation, identify exposed persons who had not sought PEP as well as in-contact dogs at risk of developing rabies. We calculate that expenditure on PEP could at least be halved through more judicious approaches to provision of PEP, based on the histories of biting animals determined through risk assessments with bite patients. We conclude that a One Health approach to surveillance based on Integrated Bite Case Management could improve the sustainability and effectiveness of rabies elimination programmes while also improving patient care by identifying those genuinely in need of lifesaving PEP
Sustained VWFâADAMTSâ13 axis imbalance and endotheliopathy in long COVID syndrome is related to immune dysfunction
Background
Prolonged recovery is common after acute SARS-CoV-2 infection; however, the pathophysiological mechanisms underpinning Long COVID syndrome remain unknown. VWF/ADAMTS-13 imbalance, dysregulated angiogenesis, and immunothrombosis are hallmarks of acute COVID-19. We hypothesized that VWF/ADAMTS-13 imbalance persists in convalescence together with endothelial cell (EC) activation and angiogenic disturbance. Additionally, we postulate that ongoing immune cell dysfunction may be linked to sustained EC and coagulation activation.
Patients and methods
Fifty patients were reviewed at a minimum of 6âweeks following acute COVID-19. ADAMTS-13, Weibel Palade Body (WPB) proteins, and angiogenesis-related proteins were assessed and clinical evaluation and immunophenotyping performed. Comparisons were made with healthy controls (n = 20) and acute COVID-19 patients (n = 36).
Results
ADAMTS-13 levels were reduced (p = 0.009) and the VWF-ADAMTS-13 ratio was increased in convalescence (p = 0.0004). Levels of platelet factor 4 (PF4), a putative protector of VWF, were also elevated (p = 0.0001). A non-significant increase in WPB proteins Angiopoietin-2 (Ang-2) and Osteoprotegerin (OPG) was observed in convalescent patients and WPB markers correlated with EC parameters. Enhanced expression of 21 angiogenesis-related proteins was observed in convalescent COVID-19. Finally, immunophenotyping revealed significantly elevated intermediate monocytes and activated CD4+ and CD8+ T cells in convalescence, which correlated with thrombin generation and endotheliopathy markers, respectively.
Conclusion
Our data provide insights into sustained EC activation, dysregulated angiogenesis, and VWF/ADAMTS-13 axis imbalance in convalescent COVID-19. In keeping with the pivotal role of immunothrombosis in acute COVID-19, our findings support the hypothesis that abnormal T cell and monocyte populations may be important in the context of persistent EC activation and hemostatic dysfunction during convalescence
ADAMTS13 regulation of VWF multimer distribution in severe COVIDâ19
Background
Consistent with fulminant endothelial cell activation, elevated plasma von Willebrand factor (VWF) antigen levels have been reported in patients with COVID-19. The multimeric size and function of VWF are normally regulated through A Disintegrin And Metalloprotease with ThrombSpondin Motif type 1 motif, member 13 (ADAMTS-13)--mediated proteolysis.
Objectives
This study investigated the hypothesis that ADAMTS-13 regulation of VWF multimer distribution may be impaired in severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection contributing to the observed microvascular thrombosis.
Patients and Methods
Patients with COVID-19 (n = 23) were recruited from the Beaumont Hospital Intensive Care Unit (ICU) in Dublin. Plasma VWF antigen, multimer distribution, ADAMTS-13 activity, and known inhibitors thereof were assessed.
Results
We observed markedly increased VWF collagen-binding activity in patients with severe COVID-19 compared to controls (median 509.1 versus 94.3 IU/dl). Conversely, plasma ADAMTS-13 activity was significantly reduced (median 68.2 IU/dl). In keeping with an increase in VWF:ADAMTS-13 ratio, abnormalities in VWF multimer distribution were common in patients with COVID-19, with reductions in high molecular weight VWF multimers. Terminal sialylation regulates VWF susceptibility to proteolysis by ADAMTS-13 and other proteases. We observed that both N- and O-linked sialylation were altered in severe COVID-19. Furthermore, plasma levels of the ADAMTS-13 inhibitors interleukin-6, thrombospondin-1, and platelet factor 4 were significantly elevated.
Conclusions
These findings support the hypothesis that SARS-CoV-2 is associated with profound quantitative and qualitative increases in plasma VWF levels, and a multifactorial down-regulation in ADAMTS-13 function. Further studies will be required to determine whether therapeutic interventions to correct ADAMTS-13-VWF multimer dysfunction may be useful in COVID-microvascular thrombosis and angiopathy
Interactive effects of temperature and salinity on otolith chemistry: challenges for determining environmental histories of fish
A standardisation framework for bioâlogging data to advance ecological research and conservation
Bioâlogging data obtained by tagging animals are key to addressing global conservation challenges. However, the many thousands of existing bioâlogging datasets are not easily discoverable, universally comparable, nor readily accessible through existing repositories and across platforms, slowing down ecological research and effective management. A set of universal standards is needed to ensure discoverability, interoperability and effective translation of bioâlogging data into research and management recommendations.
We propose a standardisation framework adhering to existing data principles (FAIR: Findable, Accessible, Interoperable and Reusable; and TRUST: Transparency, Responsibility, User focus, Sustainability and Technology) and involving the use of simple templates to create a data flow from manufacturers and researchers to compliant repositories, where automated procedures should be in place to prepare data availability into four standardised levels: (a) decoded raw data, (b) curated data, (c) interpolated data and (d) gridded data. Our framework allows for integration of simple tabular arrays (e.g. csv files) and creation of sharable and interoperable network Common Data Form (netCDF) files containing all the needed information for accuracyâofâuse, rightful attribution (ensuring data providers keep ownership through the entire process) and data preservation security.
We show the standardisation benefits for all stakeholders involved, and illustrate the application of our framework by focusing on marine animals and by providing examples of the workflow across all data levels, including filled templates and code to process data between levels, as well as templates to prepare netCDF files ready for sharing.
Adoption of our framework will facilitate collection of Essential Ocean Variables (EOVs) in support of the Global Ocean Observing System (GOOS) and interâgovernmental assessments (e.g. the World Ocean Assessment), and will provide a starting point for broader efforts to establish interoperable bioâlogging data formats across all fields in animal ecology
Advances in Cryogenic Avalanche Detectors
Cryogenic Avalanche Detectors (CRADs) are referred to as a new class of
noble-gas detectors operated at cryogenic temperatures with electron
avalanching performed directly in the detection medium, the latter being in
gaseous, liquid or two-phase (liquid-gas) state. Electron avalanching is
provided by Micro-Pattern Gas Detector (MPGD) multipliers, in particular GEMs
and THGEMs, operated at cryogenic temperatures in dense noble gases. The final
goal for this kind of detectors is the development of large-volume detectors of
ultimate sensitivity for rare-event experiments and medical applications, such
as coherent neutrino-nucleus scattering, direct dark matter search,
astrophysical (solar and supernova) neutrino detection experiments and Positron
Emission Tomography technique. This review is the first attempt to summarize
the results on CRAD performances obtained by different groups. A brief overview
of the available CRAD concepts is also given and the most remarkable CRAD
physics effects are discussed.Comment: 60 pages, 58 figures. Invited talk at MPGD2011 Conference, Aug 29 -
Sep 3, 2011, Kobe, Japan. Journal version + Fig. 1a adde
Bacterial cellulose and bacterial cellulose/polycaprolactone composite as tissue substitutes in rabbits' cornea
Conformal Higher Spin Symmetries of 4d Massless Supermultiplets and Invariant Equations in Generalized (Super)Space
Realization of the conformal higher spin symmetry on the 4d massless field
supermultiplets is given. The self-conjugated supermultiplets, including the
linearized SYM theory, are considered in some detail. Duality
between non-unitary field-theoretical representations and the unitary
doubleton--type representations of the 4d conformal algebra is
formulated in terms of a Bogolyubov transform. The set of 4d massless fields of
all spins is shown to form a representation of .
The obtained results are extended to the generalized superspace invariant
under supersymmetries. World line particle interpretation of the
free higher spin theories in the invariant (super)space is
given. Compatible with unitarity free equations of motion in the
invariant (super)space are formulated. A conjecture on the chain of
dualities in the higher spin
gauge theories is proposed.Comment: Latex, 63 pages; no figures.V2 Typos corrected, References updated.
V3.Typos correced, references and an explanation on the relationship with
previous work in section 4 are added. The version to appear in Phys.Rev.
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