1,399 research outputs found
Sievert or Gray: Dose Quantities and Protection Levels in Emergency Exposure
Mitigation or even elimination of adverse effects caused by ionizing radiation is the main scope of the radiation protection discipline. The interaction of radiation with living matter is quantified and correlated with biological effects by dose. The Sievert is the most well-known quantity, and it is used with the equivalent and effective dose to minimize stochastic effects. However, Gray is the reference quantity for sizing tissue reactions that could occur under high-exposure conditions such as in a radiation emergency. The topics addressed in this review are the choice to move from Sievert to Gray, how the operational quantities for environmental and individual monitoring of the detectors should consider such a change of units, and why reference levels substitute dose levels in emergency exposure
Circuit quantum acoustodynamics with surface acoustic waves
The experimental investigation of quantum devices incorporating mechanical
resonators has opened up new frontiers in the study of quantum mechanics at a
macroscopic level. Superconducting microwave circuits have proven to be
a powerful platform for the realisation of such quantum devices, both in cavity
optomechanics, and circuit quantum electro-dynamics (QED).
While most experiments to date have involved localised nanomechanical
resonators, it has recently been shown that propagating surface acoustic waves
(SAWs) can be piezoelectrically coupled to superconducting qubits, and
confined in high-quality Fabry-Perot cavities up to microwave frequencies in
the quantum regime, indicating the possibility of realising coherent
exchange of quantum information between the two systems. Here we present
measurements of a device in which a superconducting qubit is embedded in, and
interacts with, the acoustic field of a Fabry-Perot SAW cavity on quartz,
realising a surface acoustic version of cavity quantum electrodynamics. This
quantum acoustodynamics (QAD) architecture may be used to develop new quantum
acoustic devices in which quantum information is stored in trapped on-chip
surface acoustic wavepackets, and manipulated in ways that are impossible with
purely electromagnetic signals, due to the times slower speed of
travel of the mechanical waves.Comment: 12 pages, 9 figures, 1 tabl
Deep inside of gastric signet-ring cell carcinoma
The histology of signet-ring cell carcinoma (SRC) of the stomach has been revisited with the support of current immunohistochemical techniques in order to explain particular features of this tumor; its great capacity of local diffusion and lymph node metastasis, also through a neo-lymphoangiogenesis. An observational retrospective study on 50 cases of SRC in stage II and III has been performed with the addition of histochemical (Alcian Blue, DDD-Fast Blue B, Mercury Orange) and immunohistochemical (cytocheratin, CD3, CD4, CD8, CD10, CD56, CD68, perforin, granzyme B, podoplanin, collagen type IV) investigations for each case. The signet ring cells, typical for this tumor, show abundant content of electro-negative sialomucins and demonstrate a great capacity of diffusion through the gastric wall. They evoke production and deposition of collagen type IV in the sub-mucosa layer through the local action of fibroblasts. The immunological response to this tumor in the gastric wall and in the metastatic lymph nodes is represented by an increase of B and T-helper lymphocytes, but not of T-killers or natural killers. The neoplastic cells are curiously able to avoid these newly formed ‘lymph nodules’. An extended neo-lymphangiogenesis has been observed around the primary tumor and in metastatic lymph nodes. A careful immunohistochemical characterization has allowed a better knowledge of SRC, regarding especially the peculiar behavior of local diffusion of its cells, the associated neo-lymph angiogenesis, and poor immunological reaction
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