39 research outputs found
Deficiency in Perlecan/HSPG2 During Bone Development Enhances Osteogenesis and Decreases Quality of Adult Bone in Mice
Perlecan/HSPG2 (Pln) is a large heparan sulfate proteoglycan abundant in the extracellular matrix of cartilage and the lacunocanalicular space of adult bones. Although Pln function during cartilage development is critical, evidenced by deficiency disorders including SchwartzâJampel Syndrome and dyssegmental dysplasia Silverman-Handmaker type, little is known about its function in development of bone shape and quality. The purpose of this study was to understand the contribution of Pln to bone geometric and mechanical properties. We used hypomorph mutant mice that secrete negligible amount of Pln into skeletal tissues and analyzed their adult bone properties using micro-computed tomography and three-point-bending tests. Bone shortening and widening in Pln mutants was observed and could be attributed to loss of growth plate organization and accelerated osteogenesis that was reflected by elevated cortical thickness at older ages. This effect was more pronounced in Pln mutant females, indicating a sex-specific effect of Pln deficiency on bone geometry. Additionally, mutant females, and to a lesser extent mutant males, increased their elastic modulus and bone mineral densities to counteract changes in bone shape, but at the expense of increased brittleness. In summary, Pln deficiency alters cartilage matrix patterning and, as we now show, coordinately influences bone formation and calcification
Ultrasound-assisted intravascular therapy: history and future perspectives of development. A review
The first use of ultrasound in treating vascular disorders dates back to 1976. Since then, numerous original studies have been published, offering various concepts of its use. Many technical solutions have been developed and used with variable success, some of which have been developed in modern medicine. This article discusses the development of ultrasound therapeutic technologies in treating vascular disorders. The history of methods is described, available data on promising future areas are presented, and information on existing methods and devices is given
Electric dipole moments and the search for new physics
Static electric dipole moments of nondegenerate systems probe mass scales for
physics beyond the Standard Model well beyond those reached directly at high
energy colliders. Discrimination between different physics models, however,
requires complementary searches in atomic-molecular-and-optical, nuclear and
particle physics. In this report, we discuss the current status and prospects
in the near future for a compelling suite of such experiments, along with
developments needed in the encompassing theoretical framework.Comment: Contribution to Snowmass 2021; updated with community edits and
endorsement
Probing the Repulsive Core of the Nucleon-Nucleon Interaction via the 4He(e,e'pN) Triple-Coincidence Reaction
We studied simultaneously the 4He(e,e'p), 4He(e,e'pp), and 4He(e,e'pn)
reactions at Q^2=2 [GeV/c]2 and x_B>1, for a (e,e'p) missing-momentum range of
400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a
proton or neutron recoiling almost back to back to the missing momentum,
leaving the residual A=2 system at low excitation energy. These data were used
to identify two-nucleon short-range correlated pairs and to deduce their
isospin structure as a function of missing momentum in a region where the
nucleon-nucleon force is expected to change from predominantly tensor to
repulsive. Neutron-proton pairs dominate the high-momentum tail of the nucleon
momentum distributions, but their abundance is reduced as the nucleon momentum
increases beyond ~500 MeV/c. The extracted fraction of proton-proton pairs is
small and almost independent of the missing momentum in the range we studied.
Our data are compared with ab-initio calculations of two-nucleon momentum
distributions in 4He.Comment: 6 pages, 2 figure
Measurement of the inclusive isolated-photon cross section in pp collisions at âs = 13 TeV using 36 fbâ1 of ATLAS data
The differential cross section for isolated-photon production in pp collisions is measured at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC using an integrated luminosity of 36.1 fb. The differential cross section is presented as a function of the photon transverse energy in different regions of photon pseudorapidity. The differential cross section as a function of the absolute value of the photon pseudorapidity is also presented in different regions of photon transverse energy. Next-to-leading-order QCD calculations from Jetphox and Sherpa as well as next-to-next-to-leading-order QCD calculations from Nnlojet are compared with the measurement, using several parameterisations of the proton parton distribution functions. The predictions provide a good description of the data within the experimental and theoretical uncertainties. [Figure not available: see fulltext.
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
Kernelization of Graph Hamiltonicity - Proper H-Graphs
We obtain new polynomial kernels and compression algorithms for PATH COVER and CYCLE COVER, the well-known generalizations of the classical HAMILTONIAN PATH and HAMILTONIAN CYCLE problems. Our choice of parameterization is strongly influenced by the work of Biro, Hujter, and Tuza, who in 1992 introduced H-graphs, intersection graphs of connected subgraphs of a subdivision of a fixed (multi) graph H. In this work, we turn to proper H-graphs, where the containment relationship between the representations of the vertices is forbidden. As the treewidth of a graph measures how similar the graph is to a tree, the size of graph H is the parameter measuring the closeness of the graph to a proper interval graph. We prove the following results.- PATH COVER admits a kernel of size O(parallel to H parallel to(8)), that is, we design an algorithm that for an n-vertex graph G and an integer k >= 1, in time polynomial in n and parallel to H parallel to, outputs a graph G' of size O(parallel to H parallel to(8)) and k'- CYCLE COVER admits a compression of size O(parallel to H parallel to(10)) into another problem, called PRIZE COLLECTING CYCLE COVER, that is, we design an algorithm that, in time polynomial in n and parallel to H parallel to, outputs an equivalent instance of PRIZE COLLECTING CYCLE COVER of size O(parallel to H parallel to(10)).In all our algorithms we assume that a proper H-decomposition is given as a part of the input.</p
How to Guard a Graph?
ISSN:0178-4617ISSN:1432-054
How to guard a graph?
We initiate the study of the algorithmic foundations of games in which a set of cops has to guard a region in a graph (or digraph) against a robber. The robber and the cops are placed on vertices of the graph; they take turns in moving to adjacent vertices (or staying). The goal of the robber is to enter the guarded region at a vertex with no cop on it. The problem is to find the minimum number of cops needed to prevent the robber from entering the guarded region. The problem is highly non-trivial even if the robberâs or the copsâ regions are restricted to very simple graphs. The computational complexity of the problem depends heavily on the chosen restriction. In particular, if the robberâs region is only a path, then the problem can be solved in polynomial time. When the robber moves in a tree, then the decision version of the problem is np-complete. Furthermore, if the robber is moving in a dag, the problem becomes pspace-complete