68 research outputs found
Generation and detection of spin-orbit coupled neutron beams
Spin-orbit coupling of light has come to the fore in nano-optics and
plasmonics, and is a key ingredient of topological photonics and chiral quantum
optics. We demonstrate a basic tool for incorporating analogous effects into
neutron optics: the generation and detection of neutron beams with coupled spin
and orbital angular momentum. He neutron spin-filters are used in
conjunction with specifically oriented triangular coils to prepare neutron
beams with lattices of spin-orbit correlations, as demonstrated by their
spin-dependant intensity profiles. These correlations can be tailored to
particular applications, such as neutron studies of topological materials
Doppler ultrasound study of portal hemodynamics in patients with Gaucher disease
Gaucher disease is a lysosomal storage disorder caused by a deficiency of the enzyme glucocerebrosidase and characterized by the presence of pathological macrophages laden with glucosylceramide. Hepatosplenomegaly is a common manifestation of Gaucher disease, but symptomatic portal hypertension is rarely seen. The study included 20 untreated adult patients with Gaucher disease (non-neuronopathic type 1) diagnosed with the presence of Gaucher cells in the bone marrow, and 20 healthy subjects as controls. The examination of patients included color Doppler ultrasonography (pulsed Doppler mode), resistive index (RI) and Doppler perfusion index (DPI) using a Toshiba Xario ultrasound machine and a convex array probe PVT-375AX (1.9-6 MHz) with the objective of analyzing portal hemodynamics. Results showed that all patients had enlarged liver and spleen, and their average sizes were significantly larger than those in the healthy controls (liver: 17.04 vs.14.02 cm; spleen: 22.2 vs. 10.74 cm). DPI values were significantly different between patients and controls (0.15 vs. 0.21). Considering DPI <0.15 indicates arterial liver hypoperfusion and hypoxia, it can be concluded that a number of patients had a problem with liver oxygenation, which may be linked to the high angiotensin-converting enzyme (ACE) levels obtained in the patients (339.42 U/L), 10 times greater than in control subjects. Since ACE is a potent vasoconstrictor produced by spleen macrophages in Gaucher disease, we can suppose that elevated ACE is associated with effects on the blood vessels of the liver and spleen
Quantum Information Approach to the Implementation of a Neutron Cavity
Using the quantum information model of dynamical diffraction we consider a
neutron cavity composed of two perfect crystal silicon blades capable of
containing the neutron wavefunction. We show that the internal confinement of
the neutrons through Bragg diffraction can be modelled by a quantum random
walk. Good agreement is found between the simulation and the experimental
implementation. Analysis of the standing neutron waves is presented in regards
to the crystal geometry and parameters; and the conditions required for
well-defined bounces are derived. The presented results enable new approaches
to studying the setups utilizing neutron confinement, such as the experiments
to measure neutron magnetic and electric dipole moments.Comment: 6 pages, 5 figure
Direct discrimination of structured light by humans
We predict and experimentally verify an entoptic phenomenon through which
humans are able to perceive and discriminate structured light with
space-varying polarization. Direct perception and discrimination is possible
through the observation of distinct profiles induced by the interaction between
the polarization gradients in a uniform-intensity beam and the radially
symmetric dichroic elements that are centered on the foveola in the macula of
the human eye. A psychophysical study was conducted where optical states with
coupled polarization and orbital angular momentum (OAM) were directed onto the
retina of participants. The participants were able to correctly discriminate
between two states, differentiated by OAM =\pm7, with an average success
probability of 77.6 % (average sensitivity d^\prime=1.7, t(9) = 5.9, p =
2\times 10^{-4}). These results enable new methods of robustly characterizing
the structure of the macula, probing retina signalling pathways, and conducting
experiments with non-separable optical states and human detectors
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