43 research outputs found
AEGIS at CERN: Measuring Antihydrogen Fall
The main goal of the AEGIS experiment at the CERN Antiproton Decelerator is
the test of fundamental laws such as the Weak Equivalence Principle (WEP) and
CPT symmetry. In the first phase of AEGIS, a beam of antihydrogen will be
formed whose fall in the gravitational field is measured in a Moire'
deflectometer; this will constitute the first test of the WEP with antimatter.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
Adaptation of the Landau-Migdal Quasiparticle Pattern to Strongly Correlated Fermi Systems
A quasiparticle pattern advanced in Landau's first article on Fermi liquid
theory is adapted to elucidate the properties of a class of strongly correlated
Fermi systems characterized by a Lifshitz phase diagram featuring a quantum
critical point (QCP) where the density of states diverges. The necessary
condition for stability of the Landau Fermi Liquid state is shown to break down
in such systems, triggering a cascade of topological phase transitions that
lead, without symmetry violation, to states with multi-connected Fermi
surfaces. The end point of this evolution is found to be an exceptional state
whose spectrum of single-particle excitations exhibits a completely flat
portion at zero temperature. Analysis of the evolution of the temperature
dependence of the single-particle spectrum yields results that provide a
natural explanation of classical behavior of this class of Fermi systems in the
QCP region.Comment: 26 pages, 14 figures. Dedicated to 100th anniversary of A.B.Migdal
birthda
Mathematics in Medical Diagnostics - 2022 Proceedings of the 4th International Conference on Trauma Surgery Technology
The 4th event of the Giessen International Conference Series on Trauma Surgery Technology took place on April, the 23rd 2022 in Warsaw, Poland. It aims to bring together practical application research, with a focus on medical imaging, and the TDA experts from Warsaw. This publication contains details of our presentations and discussions
Blooming Artifact Reduction in Coronary Artery Calcification by A New De-blooming Algorithm: Initial Study
The aim of this study was to investigate the use of de-blooming algorithm in coronary CT angiography (CCTA) for optimal evaluation of calcified plaques. Calcified plaques were simulated on a coronary vessel phantom and a cardiac motion phantom. Two convolution kernels, standard (STND) and high-definition standard (HD STND), were used for imaging reconstruction. A dedicated de-blooming algorithm was used for imaging processing. We found a smaller bias towards measurement of stenosis using the deblooming algorithm (STND: bias 24.6% vs 15.0%, range 10.2% to 39.0% vs 4.0% to 25.9%; HD STND: bias 17.9% vs 11.0%, range 8.9% to 30.6% vs 0.5% to 21.5%). With use of de-blooming algorithm, specificity for diagnosing significant stenosis increased from 45.8% to 75.0% (STND), from 62.5% to 83.3% (HD STND); while positive predictive value (PPV) increased from 69.8% to 83.3% (STND), from 76.9% to 88.2% (HD STND). In the patient group, reduction in calcification volume was 48.1 ± 10.3%, reduction in coronary diameter stenosis over calcified plaque was 52.4 ± 24.2%. Our results suggest that the novel de-blooming algorithm could effectively decrease the blooming artifacts caused by coronary calcified plaques, and consequently improve diagnostic accuracy of CCTA in assessing coronary stenosis
Immediate and 12Â months follow up of function and lead integrity after cranial MRI in 356 patients with conventional cardiac pacemakers
In situ detection of cells and biochemical reactions by optical diffraction
The combination of mesoscopic surface patterning and Fourier diffraction optics represents a new sensor concept for (bio)chemical applications. Antibodies have been covalently linked to microstructures formed by μCP and provide the basis for the in situ detection of cells, which serve as scattering elements for the incident laser beam
Immobilization of antibodies in micropatterns for cell detection by optical diffraction
Optical diffraction at biochemically microstructured surfaces has been investigated for the label-free in situ detection of cells. The new sensor concept is based on regular arrays of covalently coupled antibodies, which selectively bind cells from solution. Due to the adsorption process, changes are imposed on the intensity distribution of the diffracted light, which can serve to quantify the amount of adsorbed cells. For the formation of such microstructures, different classical film preparation techniques were transferred to a mesoscopic scale by the use of microcontact printing (μCP). Alternatively, receptors were functionalized with thiol groups prior to the immobilization process and directly printed onto the gold surface. Compared to imprinting of non-functionalized proteins on gold, a better replication of the micropatterns could be obtained. Additionally, a significantly lower amount of defects was observed than for the classical coupling techniques. Using such microstructures, first experiments on the detection of Escherichia coli bacteria were performed. Diffraction patterns have been observed for concentrations equal or higher than 106 cells/ml. In time dependent experiments, diffraction spots occurred after 30 – 90 min or 10 – 20 min, depending on whether non-specific cell adsorption or specific binding to anti-E. coli IgG was studied. A first quantitative analysis of the diffraction patterns shows that the total amount of diffracted light increases with increasing incubation time