By means of the usual definition of inner product and of the Gauss condition on the sum of squares of three integers in number theory, it can be seen that there exist specific directions in ...continuous space in which a classical point particle moving in a three-dimensional lattice cannot propagate. When representing all directions for which propagation is possible as points on a unitary sphere, the forbidden directions appear as vacancies on this sphere. By means of a stereographic projection of the allowed direction, it is argued that propagation is not allowed for specific sets of points on the stereographic plane. The present work can be considered as an interdisciplinary lecture for advanced high-school students or to first-year college students.
A generalization of the semi-classical model describing the Josephson dynamics of tri-layer superconducting systems is given by assuming a constant non-null arbitrary superconducting phase for the ...inner electrode and the presence of inhomogeneities in the superconducting coupling between electrodes. Extension of the model to triple-barrier Josephson junctions is proposed. Integer and fractional Shapiro steps are predicted and their amplitudes are calculated.
Background
The Standardized Uptake Value (SUV) Max, SUVMean, and SUVPeak are metrics used to quantify positron emission tomography (PET) images. In order to assess the significance of a change in ...these metrics for diagnostic purposes, it is relevant to know their variation. The sources of variation can be biological or technical. In this study, we present a method to determine the statistical technical variation of SUV in PET images.
Results
This method was tested on a NEMA quality phantom with spheres of various diameters with a full-length acquisition time of 150 s per bed position and foreground-to-background activity ratio of F
18
-2-fluoro-2-deoxy-
d
-glucose (FDG) of 10:1. Our method divides the 150 s acquisition into subsets with statistically independent frames of shorter reconstruction length. SUVMax, Mean and Peak were calculated for each reconstructed image in a subset. The coefficient of variation of SUV within each subset has been used to estimate the expected coefficient of variation at 150 s reconstruction length. We report the largest coefficient of variation of the SUV metrics for the smallest sphere and the smallest variation for the largest sphere. The expected variation at 150 s reconstruction length does not exceed 6% for the smallest sphere and 2% for the largest sphere.
Conclusions
With the presented method, we aim to determine the statistical technical variation of SUV. The method enables the evaluation of the effect of SUV metric choice (Max, Mean, Peak) and lesion size on the technical variation and, therefore, to evaluate its relevance on the total variation of the SUV value between clinical studies.
Abstract
We demonstrate the construction and utilization of an affordable apparatus using readily available materials to accurately measure in a quantitative manner the wavelengths reflected by a ...compact disc (CD) under skimming light rays. In fact, only a limited number of wavelengths can be revealed when light rays from a white lamp are directed at a CD (or a DVD) in a manner that specifically selects the rays that graze the surface of the horizontally held disc. We compare the results with the ones obtained with a commercial spectrometer, finding that they are in good agreement among them and with the theoretical predictions.
•Development of a FEM-based design optimization tool for sacrificial PFCs provided with innovative substrate materials.•Impact on PFC due to independent combinations of absorbed energy and substrate ...properties was investigated.•User defined operating criteria of the PFC were imposed for design optimization.•An original and parametric solid model was tuned to produce tailored W lattices to fulfil several criteria.
Towards the realization of nuclear fusion, a future reactor must provide efficient and safe power exhaust through both the divertor and FW. Recent studies suggest that the greatest engineering challenges of plasma-facing components (PFCs) may arise from the occurrence of plasma transients, when extreme heat fluxes are expected. In severe cases, extensive surface vaporization, melting and re-solidification may lead to excessive degradation of conventional PFCs. An eventual failure would compromise the reactor safety as well as its prompt return to normal operation. A sacrificial limiter provided with a micro-engineered substrate material is being investigated for DEMO to cope with the harsh conditions occurring during unmitigated plasma disruptions. Among the possible solutions, innovative materials such as tungsten (W) based lattice structures can be tailored to meet functional requirements and prevent severe failures. As a further step in this direction, an equivalent solid model, originally developed and validated for open-cell Al foams, was transferred to W foams and the scaling law of its thermo-physical properties evaluated as a function of the most influential parameters. In the present work, a design optimization tool for the thermal behavior of the substrate material is presented. The latter is modeled as a homogeneous material having equivalent properties. A parametric design study was carried out to assess their impact on the global behavior of the PFC. Independent combinations of equivalent thermal conductivity and density have been applied to the substrate material by scaling the corresponding properties of bulk W. For each design point, results were tabulated and compared with user-defined operating requirements. Afterwards, a post-processing routine was implemented for effective visualization of the space of solutions. Ultimately, tailored lattice structures potentially able to fulfill the operating requirements are proposed. An existing solid model for open-cell W foams was employed to design the features of such material based on the results of the parametric study.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD) characterized by damage of large bowel mucosa and frequent extra-intestinal autoimmune comorbidities. The role played in IBD ...pathogenesis by molecular chaperones known to interact with components of the immune system involved in inflammation is unclear. We previously demonstrated that mucosal Hsp60 decreases in UC patients treated with conventional therapies (mesalazine, probiotics), suggesting that this chaperonin could be a reliable biomarker useful for monitoring response to treatment, and that it might play a role in pathogenesis. In the present work we investigated three other heat shock protein/molecular chaperones: Hsp10, Hsp70, and Hsp90. We found that the levels of these proteins are increased in UC patients at the time of diagnosis and decrease after therapy, supporting the notion that these proteins deserve attention in the study of the mechanisms that promote the development and maintenance of IBD, and as biomarkers of this disease (e.g., to monitor response to treatment at the histological level).
The onset of double-diffusive convection in horizontal porous layers for the thermo-diffusive Soret phenomenon in the case of a generalized Darcy model including inertia term is investigated. Via a ...linearization principle recently introduced in Rionero (Atti Accad Naz Lincei Rend Cl Sci Fis Mat Natur 28:21–47,
2017
) the coincidence between linear and nonlinear (global) stability thresholds of the thermo-solutal conduction solution, is proved. Necessary and sufficient conditions guaranteeing the onset of steady or oscillatory convection in a closed algebraic form are obtained.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Highlights • Maternal deprivation induces schizophrenia-like behavior in offspring. • Cholinergic system of the offspring is disrupted by maternal deprivation. • Maternal deprivation exacerbates the ...effects of ketamine on offspring.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A system modeling fluid motions in horizontal porous layers, uniformly heated from below and salted from above by one salt, is analyzed. The definitely boundedness of solutions (existence of ...absorbing sets) is proved. Necessary and sufficient conditions ensuring the linear stability of a vertical constant throughflow have been obtained via a new approach. Moreover, conditions guaranteeing the global non-linear asymptotic stability are determined.
•A system modeling fluid motions in horizontal porous layers, uniformly heated from below and salted from above by one salt, is analyzed.•The definitely boundedness of solutions (existence of absorbing sets) is proved.•Via the Rionero approach, necessary and sufficient conditions ensuring the linear stability of a vertical constant throughflow have been obtained.•Conditions guaranteeing the global non-linear asymptotic stability are determined.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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