Quantitative Intensity Harmonization of Dopamine Transporter SPECT Images Using Gamma Mixture Models

PURPOSE: Differences in site, device, and/or settings may cause large variations in the intensity profile of dopamine transporter (DAT) single-photon emission computed tomography (SPECT) images. However, the current standard to evaluate these images, the striatal binding ratio (SBR), does not efficiently account for this heterogeneity and the assessment can be unequivalent across distinct acquisition pipelines. In this work, we present a voxel-based automated approach to intensity normalize such type of data that improves on cross-session interpretation. PROCEDURES: The normalization method consists of a reparametrization of the voxel values based on the cumulative density function (CDF) of a Gamma distribution modeling the specific region intensity. The harmonization ability was tested in 1342 SPECT images from the PPMI repository, acquired with 7 distinct gamma camera models and at 24 different sites. We compared the striatal quantification across distinct cameras for raw intensities, SBR values, and after applying the Gamma CDF (GDCF) harmonization. As a proof-of-concept, we evaluated the impact of GCDF normalization in a classification task between controls and Parkinson disease patients. RESULTS: Raw striatal intensities and SBR values presented significant differences across distinct camera models. We demonstrate that GCDF normalization efficiently alleviated these differences in striatal quantification and with values constrained to a fixed interval [0, 1]. Also, our method allowed a fully automated image assessment that provided maximal classification ability, given by an area under the curve (AUC) of AUC = 0.94 when used mean regional variables and AUC = 0.98 when used voxel-based variables. CONCLUSION: The GCDF normalization method is useful to standardize the intensity of DAT SPECT images in an automated fashion and enables the development of unbiased algorithms using multicenter datasets. This method may constitute a key pre-processing step in the analysis of this type of images.Instituto de Salud Carlos III FI14/00497 MV15/00034Fondo Europeo de Desarrollo Regional FI14/00497 MV15/00034ISCIII-FEDER PI16/01575Wellcome Trust UK Strategic Award 098369/Z/12/ZNetherland Organization for Scientific Research NWO-Vidi 864-12-00

Hamiltonian facets of classical gauge theories on EE-manifolds

Manifolds with boundary, with corners, $b$-manifolds and foliations model configuration spaces for particles moving under constraints and can be described as $E$-manifolds. $E$-manifolds were introduced in [NT01] and investigated in depth in [MS20]. In this article we explore their physical facets by extending gauge theories to the $E$-category. Singularities in the configuration space of a classical particle can be described in several new scenarios unveiling their Hamiltonian aspects on an $E$-symplectic manifold. Following the scheme inaugurated in [Wei78], we show the existence of a universal model for a particle interacting with an $E$-gauge field. In addition, we generalize the description of phase spaces in Yang-Mills theory as Poisson manifolds and their minimal coupling procedure, as shown in [Mon86], for base manifolds endowed with an $E$-structure. In particular, the reduction at coadjoint orbits and the shifting trick are extended to this framework. We show that Wong's equations, which describe the interaction of a particle with a Yang-Mills field, become Hamiltonian in the $E$-setting. We formulate the electromagnetic gauge in a Minkowski space relating it to the proper time foliation and we see that our main theorem describes the minimal coupling in physical models such as the compactified black hole.Comment: 38 pages, 6 figure

Synaptic processes and immune-related pathways implicated in Tourette syndrome

Tourette syndrome (TS) is a neuropsychiatric disorder of complex genetic architecture involving multiple interacting genes. Here, we sought to elucidate the pathways that underlie the neurobiology of the disorder through genomewide analysis. We analyzed genome-wide genotypic data of 3581 individuals with TS and 7682 ancestry-matched controls and investigated associations of TS with sets of genes that are expressed in particular cell types and operate in specific neuronal and glial functions. We employed a self-contained, set-based association method (SBA) as well as a competitive gene set method (MAGMA) using individual-level genotype data to perform a comprehensive investigation of the biological background of TS. Our SBA analysis identified three significant gene sets after Bonferroni correction, implicating ligand-gated ion channel signaling, lymphocytic, and cell adhesion and transsynaptic signaling processes. MAGMA analysis further supported the involvement of the cell adhesion and trans-synaptic signaling gene set. The lymphocytic gene set was driven by variants in FLT3, raising an intriguing hypothesis for the involvement of a neuroinflammatory element in TS pathogenesis. The indications of involvement of ligand-gated ion channel signaling reinforce the role of GABA in TS, while the association of cell adhesion and trans-synaptic signaling gene set provides additional support for the role of adhesion molecules in neuropsychiatric disorders. This study reinforces previous findings but also provides new insights into the neurobiology of TS

Combining tariffs, investment subsidies and soft loans in a renewable electricity deployment policy

Policy combinations and interactions have received a considerable attention in the energy policy realm. The aim of our working paper is to provide insight on the costeffectiveness of combinations of deployment instruments for the same technology. A financial model is developed for this purpose, whereby feed-in tariffs (FITs) and premiums (FIPs) are combined with investment subsidies and soft loans. The results show that combinin deployment instruments is not a cost-containment strategy. However, combinations may lead to different inter-temporal distributions of the same amount of policy costs which can affect the social acceptability and political feasibility of renewable energy support

Practical guidance for easily interpreting the emission and physicochemical parameters of Eu3+ in solid-state hosts

Materials doped with the luminescent Eu3+ ion are attracting an ever-increasing amount of attention due to their potential applications in solid-state lighting, display devices, solar cells, or bioanalytics. But, why Eu3+? Unlike other lanthanides, its electronic features make the calculation of some physicochemical parameters quite straightforward, since they can be extracted directly from the emission spectrum. Highly appreciated for its reddish emission, the luminescent ion has also been widely used as a site-sensitive structural probe. With this in mind, this paper aims to offer easy guidance with helpful advice on how to interpret measurements of the emission spectra. It also presents the most useful tools for saving time, and gives a focused and practical explanation of the theoretical concepts involved.Funding for open access charge: CRUE-Universitat Jaume

The unexplored δ-phase of KY3F10: toward novel Eu3+-doped nanoplates with a ‘super-diamond’ structure for optical applications

This article describes a new, simple, and high-yield method based on a sonochemical process for obtaining the δ-KY3F10·xH2O compound with a ‘super-diamond’ structure, a material that has been completely neglected in the literature since it was first discovered. We explore the mechanism underlying the formation of the synthesized nanomaterials and show their connection with the pH of the medium. Additionally, we demonstrate for the first time the adequacy of the δ-phase of KY3F10 for optical applications through the novel Eu3+-doped nanoplates, which exhibit long lifetimes and high quantum efficiencies. The results reveal that this material, which also has zeolitic characteristics, can have a strong impact on future photonic and associated applications

Unraveling the superior role of dicarboxylic acids as surface chelators in Eu3+-doped yttrium fluorides: A systematic modulation of the crystal phases and morphologies for highly tuned optical performance

Eu3+-doped YF3 and KY3F10 phosphors have been prepared hydrothermally in a wide range of pH values without the use of surface chelators and adding oxalic or tartaric acid. We have proved, for the first time, the usefulness of dicarboxylic acids to modulate the evolution of the surface and crystal phases in the KF-YF3 system. The morphologies and crystal structures of the materials displayed a critical dependence on the pH and the chelator employed, and a plausible mechanism to explain the differences among the distinct series of samples is proposed. As a result, the fluorides exhibited outstanding and tunable photoluminescence, with extremely high quantum efficiencies and very long lifetimes. The asymmetry ratio and Judd-Ofelt parameters calculations allowed us to establish a relationship between the optical performance of the compounds and their physicochemical properties. We feel that this study can arouse widespread interest within the materials engineering community, since similar procedures could be implemented to the extended family of complex yttrium/lanthanide fluorides for advanced applications in important fields such as bioanalytics, biomedics, or photonics. Indeed, the materials in the present work, with orangish-yellow colored emissions, could be very interesting for application in white light emitting diodes through their combination with blue chips