2,808 research outputs found
Revealing the Meissner Corpuscles in Human Glabrous Skin Using In Vivo Non-Invasive Imaging Techniques
The presence of mechanoreceptors in glabrous skin allows humans to discriminate textures
by touch. The amount and distribution of these receptors defines our tactile sensitivity and can
be affected by diseases such as diabetes, HIV-related pathologies, and hereditary neuropathies.
The quantification of mechanoreceptors as clinical markers by biopsy is an invasive method of
diagnosis. We report the localization and quantification of Meissner corpuscles in glabrous skin using
in vivo, non-invasive optical microscopy techniques. Our approach is supported by the discovery of
epidermal protrusions which are co-localized with Meissner corpuscles. Index fingers, small fingers,
and tenar palm regions of ten participants were imaged by optical coherence tomography (OCT) and
laser scan microscopy (LSM) to determine the thickness of the stratum corneum and epidermis and
to count the Meissner corpuscles. We discovered that regions containing Meissner corpuscles could
be easily identified by LSM with an enhanced optical reflectance above the corpuscles, caused by a
protrusion of the strongly reflecting epidermis into the stratum corneum with its weak reflectance.
We suggest that this local morphology above Meissner corpuscles has a function in tactile perception
The accuracy of coronary CT angiography in patients with coronary calcium score above 1000 Agatston Units:Comparison with quantitative coronary angiography: Coronary CT Angiography in High Coronary Calcium
BACKGROUND: High amounts of coronary artery calcium (CAC) pose challenges in interpretation of coronary CT angiography (CCTA). The accuracy of stenosis assessment by CCTA in patients with very extensive CAC is uncertain. METHODS: Retrospective study was performed including patients who underwent clinically directed CCTA with CAC score >1000 and invasive coronary angiography within 90 days. Segmental stenosis on CCTA was graded by visual inspection with two-observer consensus using categories of 0%, 1–24%, 25–49%, 50–69%, 70–99%, 100% stenosis, or uninterpretable. Blinded quantitative coronary angiography (QCA) was performed on all segments with stenosis ≥25% by CCTA. The primary outcome was vessel-based agreement between CCTA and QCA, using significant stenosis defined by diameter stenosis ≥ 70%. Secondary analyses on a per-patient basis and inclusive of uninterpretable segments were performed. RESULTS: 726 segments with stenosis ≥25% in 346 vessels within 119 patients were analyzed. Median coronary calcium score was 1616 (1221–2118). CCTA identification of QCA-based stenosis resulted in a per-vessel sensitivity of 79%, specificity of 75%, positive predictive value (PPV) of 45%, negative predictive value (NPV) of 93%, and accuracy 76% (68 false positive and 15 false negative). Per-patient analysis had sensitivity 94%, specificity 55%, PPV 63%, NPV 92%, and accuracy 72% (30 false-positive and 3 false-negative). Inclusion of uninterpretable segments had variable effect on sensitivity and specificity, depending on whether they are considered as significant or non-significant stenosis. CONCLUSIONS: In patients with very extensive CAC (>1000 Agatston units), CCTA retained a negative predictive value > 90% to identify lack of significant stenosis on a per-vessel and per-patient level, but frequently overestimated stenosis
The Screening Cloud in the k-Channel Kondo Model: Perturbative and Large-k Results
We demonstrate the existence of a large Kondo screening cloud in the
k-channel Kondo model using both renormalization group improved perturbation
theory and the large-k limit. We study position (r) dependent spin Green's
functions in both static and equal time cases. The equal-time Green's function
provides a natural definition of the screening cloud profile, in which the
large Kondo scale appears. At large distances it consists of both a slowly
varying piece and a piece which oscillates at twice the Fermi wave-vector. This
function is calculated at all r in the large-k limit. Static Green's functions
(Knight shift or susceptibility) consist only of a term oscillating at 2kF, and
appear to factorize into a function of r times a function of T for rT << vF, in
agreement with NMR experiments. Most of the integrated susceptibility comes
from the impurity-impurity part with conduction electron contributions
suppressed by powers of the bare Kondo coupling. The single-channel and
overscreened multi-channel cases are rather similar although anomalous
power-laws occur in the latter case at large r and low T due to irrelevant
operator corrections.Comment: 22 Revtex pages, 12 figure
SARS-CoV-2 Variant of Concern B.1.1.7: Diagnostic Sensitivity of Three Antigen-Detecting Rapid Tests.
Funder: Foundation for Innovative New DiagnosticsFunder: World Health OrganizationFunder: Ministry of Science, Research and Culture, State of Baden Wuerttemberg, German
Ernst Freund as Precursor of the Rational Study of Corporate Law
Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe
International criteria for electrocardiographic interpretation in athletes: Consensus statement.
Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD
‘If I am on ART, my new-born baby should be put on treatment immediately’: Exploring the acceptability, and appropriateness of Cepheid Xpert HIV-1 Qual assay for early infant diagnosis of HIV in Malawi
Early infant diagnosis of HIV (EID-HIV) is key to reducing paediatric HIV mortality. Traditional approaches for diagnosing HIV in exposed infants are usually unable to optimally contribute to EID. Point-of-care testing such as Cepheid Xpert HIV-1 Qual assay-1 (XPertHIV) are available and could improve EID-HIV in resource constrained and high HIV burden contexts. We investigated the acceptability and perceived appropriateness of XpertHIV for EID-HIV in Mulanje Hospital, Malawi. Qualitative cross-sectional study using semi-structured interviews (SSI) among caregivers and health care workers at Mulanje District Hospital. The qualitative study was nested within a larger diagnostic study that evaluated the performance of XpertHIV using whole-blood-sample in a resource limited and high burden setting. A total of 65 SSIs were conducted among caregivers (n = 60) and health care providers (n = 5). Data were coded using deductive and inductive approaches while thematic approach was used to analyse data. Point-of-care XPertHIV was perceived to be acceptable among caregivers and health care providers. Caregivers’ motivations for accepting XPertHIV HIV-testing for their infants included perceived risk of HIV emanating from child’s exposure and validation of caregiver’s own HIV sero-status. Although concerns about pain of testing and blood sample volumes taken from an infant remained amplified, overall, both caregivers and health care providers felt XpertHIV was appropriate because of its quick result turn-around-time which decreased anxiety and stress, the prospect of early treatment initiation and reduction in hospital visits and related costs. Implementation of XpertHIV has a great potential to improve EID-HIV in Malawi because of its quick turn-around-time and associated benefits including overcoming access-related barriers. Scaled implementation of this diagnostic technology require a robust community engagement strategy for managing caregivers and community myths and misconceptions towards the amount of blood sample collected from infants
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
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