4,022 research outputs found

    Criteria for the diagnosis of corticobasal degeneration

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    Current criteria for the clinical diagnosis of pathologically confirmed corticobasal degeneration (CBD) no longer reflect the expanding understanding of this disease and its clinicopathologic correlations. An international consortium of behavioral neurology, neuropsychology, and movement disorders specialists developed new criteria based on consensus and a systematic literature review. Clinical diagnoses (early or late) were identified for 267 nonoverlapping pathologically confirmed CBD cases from published reports and brain banks. Combined with consensus, 4 CBD phenotypes emerged: corticobasal syndrome (CBS), frontal behavioral-spatial syndrome (FBS), nonfluent/agrammatic variant of primary progressive aphasia (naPPA), and progressive supranuclear palsy syndrome (PSPS). Clinical features of CBD cases were extracted from descriptions of 209 brain bank and published patients, providing a comprehensive description of CBD and correcting common misconceptions. Clinical CBD phenotypes and features were combined to create 2 sets of criteria: more specific clinical research criteria for probable CBD and broader criteria for possible CBD that are more inclusive but have a higher chance to detect other tau-based pathologies. Probable CBD criteria require insidious onset and gradual progression for at least 1 year, age at onset ≥50 years, no similar family history or known tau mutations, and a clinical phenotype of probable CBS or either FBS or naPPA with at least 1 CBS feature. The possible CBD category uses similar criteria but has no restrictions on age or family history, allows tau mutations, permits less rigorous phenotype fulfillment, and includes a PSPS phenotype. Future validation and refinement of the proposed criteria are needed

    The why and how of the SynNerGe criteria of Parkinson´s disease

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    In pursuit of early therapeutic interventions for Parkinson’s disease, the proposed SynNeurGe classification system integrates α-synuclein pathology (S), neurodegeneration evidence (N), and pathogenic gene variants (G). This approach aims to address the disease’s complexity and biological diversity. It suggests categorizing patients based on the presence or absence of α-synuclein pathology in tissues or cerebrospinal fluid, neurodegeneration indicators from specific imaging techniques, and identification of pathogenic gene variants associated with Parkinson’s disease. The proposed system emphasizes the future need for precision medicine and aims to facilitate both basic and clinical research toward disease-modifying therapies. However, the authors stress that initial implementation should be confined to research settings, considering ethical implications and current limitations. Prospective validation of these criteria is deemed necessary to ensure their efficacy and ethical application in clinical practice

    Reducing dynamic disorder in small-molecule organic semiconductors by suppressing large-amplitude thermal motions.

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    Thermal vibrations and the dynamic disorder they create can detrimentally affect the transport properties of van der Waals bonded molecular semiconductors. The low-energy nature of these vibrations makes it difficult to access them experimentally, which is why we still lack clear molecular design rules to control and reduce dynamic disorder. In this study we discuss the promising organic semiconductors rubrene, 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothio-phene and 2,9-di-decyl-dinaphtho-[2,3-b:20,30-f]-thieno-[3,2-b]-thiophene in terms of an exceptionally low degree of dynamic disorder. In particular, we analyse diffuse scattering in transmission electron microscopy, to show that small molecules that have their side chains attached along the long axis of their conjugated core are better encapsulated in their crystal structure, which helps reduce large-amplitude thermal motions. Our work provides a general strategy for the design of new classes of very high mobility organic semiconductors with a low degree of dynamic disorder.S.I. acknowledges funding from the EPSRC, the Winton Programme for the Physics of Sustainability and the Cambridge Home and EU scholarship scheme (CHESS). G. S. acknowledges postdoctoral fellowship support from the Wiener-Anspach Foundation. We acknowledge the support of Nippon Kayaku in providing the materials C8-BTBT and C10-DNTT. We acknowledge Dr John Morrison for synthesis of TMTES-P and Marie Beatrice for her work that resulted in the thin-film structure of TMTES-P. We acknowledge Audrey Richard and Christian Ruzié for the synthesis of ditBu-BTBT and diTMS-BTBT.This is the final version of the article. It first appeared from Nature Publishing Group via https://doi.org/10.1038/ncomms1073

    The helicity amplitudes A1/2_{1/2} and A3/2_{3/2} for the D13(1520)_{13}(1520) resonance obtained from the γppπ0\vec{\gamma} \vec{p} \to p \pi^0 reaction}

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    The helicity dependence of the γppπ0\vec{\gamma} \vec{p} \to p \pi^0 reaction has been measured for the first time in the photon energy range from 550 to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4π\pi-detector system, a circularly polarized, tagged photon beam, and a longitudinally polarized frozen-spin target. These data are predominantly sensitive to the D13(1520)D_{13}(1520) resonance and are used to determine its parameters.Comment: 5 pages, 4 figure

    Removing krypton from xenon by cryogenic distillation to the ppq level

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    The XENON1T experiment aims for the direct detection of dark matter in a cryostat filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the β\beta-emitter 85^{85}Kr which is an intrinsic contamination of the xenon. For the XENON1T experiment a concentration of natural krypton in xenon nat\rm{^{nat}}Kr/Xe < 200 ppq (parts per quadrillion, 1 ppq = 1015^{-15} mol/mol) is required. In this work, the design of a novel cryogenic distillation column using the common McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4\cdot105^5 with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of nat\rm{^{nat}}Kr/Xe < 26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN
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