1,883 research outputs found
Uncertainty inequalities on groups and homogeneous spaces via isoperimetric inequalities
We prove a family of uncertainty inequalities on fairly general groups
and homogeneous spaces, both in the smooth and in the discrete setting. The
crucial point is the proof of the endpoint, which is derived from a
general weak isoperimetric inequality.Comment: 17 page
Primer for intensive care unit (ICU) redeployment of the noncritical care surgeon: Insights from the epicenter of the coronavirus disease 2019 (COVID-19) pandemic
Ruptured Internal Iliac Artery Aneurysm: Staged Emergency Endovascular Treatment in the Interventional Radiology Suite
Ruptured aneurysms of the internal iliac artery (IIA) are rare and challenging to treat surgically. Due to their anatomic location they are difficult to operate on and perioperative morbidity is high. An endovascular approach can be helpful. We recently treated a patient with a ruptured IIA aneurysm in the interventional radiology suite with embolization of the side-branch of the IIA and placement of a covered stent in the ipsilateral common and external iliac arteries. A suitable stent-graft was not available initially and had to be brought in from elsewhere. An angioplasty balloon was temporarily placed across the ostium of the IIA to obtain hemostasis. Two hours later, the procedure was finished by placing the stent-graft
Superconductivity at 44 K in K intercalated FeSe system with excess Fe
We report here that a new superconducting phase with much higher Tc has been
found in K intercalated FeSe compound with excess Fe. We successfully grew
crystals by precisely controlling the starting amount of Fe. Besides the
superconducting (SC) transition at ~30 K, we observed a sharp drop in
resistivity and a kink in susceptibility at 44 K. By combining thermodynamic
measurements with electron spin resonance (ESR), we demonstrate that this is a
new SC transition. Structural analysis unambiguously reveals two phases
coexisting in the crystals, which are responsible respectively for the SC
transitions at 30 and 44 K. The structural experiments and first-principles
calculations consistently indicate that the 44 K SC phase is close to a 122
structure, but with an unexpectedly large c-axis of 18.10 {\AA}. We further
find a novel monotonic dependence of the maximum Tc on the separation of
neighbouring FeSe layers.Comment: 15 pages, 5 figure
I-CARE, a European Prospective Cohort Study Assessing Safety and Effectiveness of Biologics in Inflammatory Bowel Disease
Background and aims: There is a need to evaluate the benefit-risk ratio of current therapies in inflammatory bowel disease (IBD) patients to provide the best quality of care. The primary objective of I-CARE (IBD Cancer and serious infections in Europe) was to assess prospectively safety concerns in IBD, with specific focus on the risk of cancer/lymphoma and serious infections in patients treated with anti-tumor necrosis factor and other biologic monotherapy as well as in combination with immunomodulators.. Methods: I-CARE was designed as a European prospective longitudinal observational multicenter cohort study to include patients with a diagnosis of Crohn's disease, ulcerative colitis, or IBD unclassified established at least 3 months prior to enrollment. Results: A total of 10,206 patients were enrolled between March 2016 and April 2019, including 6169 (60.4%) patients with Crohn's disease, 3853 (37.8%) with ulcerative colitis, and 184 (1.8%) with a diagnosis of IBD unclassified. Thirty-two percent of patients were receiving azathioprine/thiopurines, 4.6% 6-mercaptopurine, and 3.2% methotrexate at study entry. At inclusion, 47.3% of patients were treated with an anti-tumor necrosis factor agent, 8.8% with vedolizumab, and 3.4% with ustekinumab. Roughly one-quarter of patients (26.8%) underwent prior IBD-related surgery. Sixty-six percent of patients had been previously treated with systemic steroids. Three percent of patients had a medical history of cancer prior to inclusion and 1.1% had a history of colonic, esophageal, or uterine cervix high-grade dysplasia.. Conclusions: I-CARE is an ongoing investigator-initiated observational European prospective cohort study that will provide unique information on the long-term benefits and risks of biological therapies in IBD patients
Dysplasia of the Upper Aerodigestive Tract Squamous Epithelium
Dysplasia of the oral, laryngeal and oropharyngeal stratified squamous epithelia is a microscopically defined change that may occur in clinically identifiable lesions including erythroplakia, leukoplakia and erythroleukoplakia, lesions that convey a heightened risk for carcinomatous progression. Dysplastic lesions have been classified microscopically according to degree of cytologic atypia and changes in architectural patterns, usually on a three part or four part gradation scale. Vocal cord epithelial lesions are graded according to either the Ljubljana or the World Health Organization (WHO) system whereas oral dysplasias are generally classified according to WHO criteria. Cytologically atypical cells are considered to represent precancerous changes predicting an increase risk for carcinomatous transformation. Inter- and intra-rater reliability studies among pathologists have disclosed low correlation coefficients for four part grading systems, whereas improved agreement is achieved (kappa correlation values) using the Ljubljana systems. Evidence forwarded by some studies supports the prognostic value of progressively severe dysplastic changes for carcinomatous transformation; however, some studies indicate that the presence of a clinically defined lesion without microscopic evidence of dysplasia also connotes increased risk for carcinomatous transformation. Loss of heterozygosity (LOH) at 3p and 9p microsatellite domains, DNA ploidy analysis and nuclear image analyses may have predictive value as molecular and histomorphological biomarkers
Lattice Boltzmann simulations of soft matter systems
This article concerns numerical simulations of the dynamics of particles
immersed in a continuum solvent. As prototypical systems, we consider colloidal
dispersions of spherical particles and solutions of uncharged polymers. After a
brief explanation of the concept of hydrodynamic interactions, we give a
general overview over the various simulation methods that have been developed
to cope with the resulting computational problems. We then focus on the
approach we have developed, which couples a system of particles to a lattice
Boltzmann model representing the solvent degrees of freedom. The standard D3Q19
lattice Boltzmann model is derived and explained in depth, followed by a
detailed discussion of complementary methods for the coupling of solvent and
solute. Colloidal dispersions are best described in terms of extended particles
with appropriate boundary conditions at the surfaces, while particles with
internal degrees of freedom are easier to simulate as an arrangement of mass
points with frictional coupling to the solvent. In both cases, particular care
has been taken to simulate thermal fluctuations in a consistent way. The
usefulness of this methodology is illustrated by studies from our own research,
where the dynamics of colloidal and polymeric systems has been investigated in
both equilibrium and nonequilibrium situations.Comment: Review article, submitted to Advances in Polymer Science. 16 figures,
76 page
Circumstellar discs: What will be next?
This prospective chapter gives our view on the evolution of the study of
circumstellar discs within the next 20 years from both observational and
theoretical sides. We first present the expected improvements in our knowledge
of protoplanetary discs as for their masses, sizes, chemistry, the presence of
planets as well as the evolutionary processes shaping these discs. We then
explore the older debris disc stage and explain what will be learnt concerning
their birth, the intrinsic links between these discs and planets, the hot dust
and the gas detected around main sequence stars as well as discs around white
dwarfs.Comment: invited review; comments welcome (32 pages
HCN Channels Are Not Required for Mechanotransduction in Sensory Hair Cells of the Mouse Inner Ear
The molecular composition of the hair cell transduction channel has not been identified. Here we explore the novel hypothesis that hair cell transduction channels include HCN subunits. The HCN family of ion channels includes four members, HCN1-4. They were orginally identified as the molecular correlates of the hyperpolarization-activated, cyclic nucleotide gated ion channels that carry currents known as If, IQ or Ih. However, based on recent evidence it has been suggested that HCN subunits may also be components of the elusive hair cell transduction channel. To investigate this hypothesis we examined expression of mRNA that encodes HCN1-4 in sensory epithelia of the mouse inner ear, immunolocalization of HCN subunits 1, 2 and 4, uptake of the transduction channel permeable dye, FM1-43 and electrophysiological measurement of mechanotransduction current. Dye uptake and transduction current were assayed in cochlear and vestibular hair cells of wildtype mice exposed to HCN channel blockers or a dominant-negative form of HCN2 that contained a pore mutation and in mutant mice that lacked HCN1, HCN2 or both. We found robust expression of HCNs 1, 2 and 4 but little evidence that localized HCN subunits in hair bundles, the site of mechanotransduction. Although high concentrations of the HCN antagonist, ZD7288, blocked 50â70% of the transduction current, we found no reduction of transduction current in either cochlear or vestibular hair cells of HCN1- or HCN2- deficient mice relative to wild-type mice. Furthermore, mice that lacked both HCN1 and HCN2 also had normal transduction currents. Lastly, we found that mice exposed to the dominant-negative mutant form of HCN2 had normal transduction currents as well. Taken together, the evidence suggests that HCN subunits are not required for mechanotransduction in hair cells of the mouse inner ear
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