116 research outputs found

    The Clinical Impact of [68Ga]‐DOTATATE PET/CT for the Diagnosis and Management of Ectopic Adrenocorticotropic Hormone – Secreting Tumours

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    ObjectivesLocalization of ectopic ACTH‐secreting tumours causing Cushing syndrome (ECS) is essential for clinical management, yet often difficult. [68Ga]‐DOTATATE PET/CT ([68Ga]‐DOTA‐(Tyr3)‐octreotate)] is an FDA‐approved high‐resolution diagnostic tool for imaging neuroendocrine tumours. Data on the clinical utility of [68Ga]‐DOTATATE in patients with ECS, however, are scarce. The objectives of this study were to determine the efficacy for ECS localization and the clinical benefit of [68Ga]‐DOTATATE imaging.MethodWe conducted a retrospective review of all cases with ECS evaluated with [68Ga]‐DOTATATE from November 2016 through October 2018 at three referral centres. The clinical benefit of [68Ga]‐DOTATATE was based on detection of new tumours and resultant changes in management.ResultsOver the study period, 28 patients with ECS underwent [68Ga]‐DOTATATE: 17 for identification of the primary tumour and 11 during follow‐up. [68Ga]‐DOTATATE identified the suspected primary ECS in 11/17 patients (65%). Of these, nine patients underwent surgery: eight with confirmed ECS (5 bronchial, 1 thymic, 1 pancreatic and 1 metastatic neuroendocrine tumour of unknown primary origin) and one patient with a false‐positive scan (adrenal gland). Of the 11 patients with ECS who underwent [68Ga]‐DOTATATE evaluation during follow‐up, the study led to changes in clinical management in 7/11 (64%) patients.Conclusions[68Ga]‐DOTATATE is sensitive in detecting primary and metastatic ECS, often identifies occult tumours after conventional imaging, and impacts clinical care in the majority of patients.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150507/1/cen14008.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150507/2/cen14008_am.pd

    Stable ultrahigh-density magneto-optical recordings using introduced linear defects

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    The stability of data bits in magnetic recording media at ultrahigh densities is compromised by thermal `flips' -- magnetic spin reversals -- of nano-sized spin domains, which erase the stored information. Media that are magnetized perpendicular to the plane of the film, such as ultrathin cobalt films or multilayered structures, are more stable against thermal self-erasure than conventional memory devices. In this context, magneto-optical memories seem particularly promising for ultrahigh-density recording on portable disks, and bit densities of \sim100 Gbit inch2^{-2} have been demonstrated using recent advances in the bit writing and reading techniques. But the roughness and mobility of the magnetic domain walls prevents closer packing of the magnetic bits, and therefore presents a challenge to reaching even higher bit densities. Here we report that the strain imposed by a linear defect in a magnetic thin film can smooth rough domain walls over regions hundreds of micrometers in size, and halt their motion. A scaling analysis of this process, based on the generic physics of disorder-controlled elastic lines, points to a simple way by which magnetic media might be prepared that can store data at densities in excess of 1 Tbit inch2^{-2}.Comment: 5 pages, 4 figures, see also an article in TRN News at http://www.trnmag.com/Stories/041801/Defects_boost_disc_capacity_041801.htm

    Critical Dynamics of Symmetry Breaking: Quenches, Dissipation and Cosmology

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    Symmetry-breaking phase transitions may leave behind topological defects \cite{Kibble} with a density dependent on the quench rate \cite{Zurek}. We investigate the dynamics of such quenches for the one-dimensional, Landau-Ginzburg case and show that the density of kinks, nn, scales differently with the quench timescale, τQ\tau_Q, depending on whether the dynamics in the vicinity of the critical point is overdamped (nτQ1/4n \propto \tau_Q^{-1/4}) or underdamped (nτQ1/3n \propto \tau_Q^{-1/3}). Either of these cases may be relevant to the early Universe, and we derive bounds on the initial density of topological defects in cosmological phase transitions.Comment: 5 pages, 4 Postscript figure

    Decoherence, einselection, and the quantum origins of the classical

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    Decoherence is caused by the interaction with the environment. Environment monitors certain observables of the system, destroying interference between the pointer states corresponding to their eigenvalues. This leads to environment-induced superselection or einselection, a quantum process associated with selective loss of information. Einselected pointer states are stable. They can retain correlations with the rest of the Universe in spite of the environment. Einselection enforces classicality by imposing an effective ban on the vast majority of the Hilbert space, eliminating especially the flagrantly non-local "Schr\"odinger cat" states. Classical structure of phase space emerges from the quantum Hilbert space in the appropriate macroscopic limit: Combination of einselection with dynamics leads to the idealizations of a point and of a classical trajectory. In measurements, einselection replaces quantum entanglement between the apparatus and the measured system with the classical correlation.Comment: Final version of the review, with brutally compressed figures. Apart from the changes introduced in the editorial process the text is identical with that in the Rev. Mod. Phys. July issue. Also available from http://www.vjquantuminfo.or

    Phenotypic Diversity and Altered Environmental Plasticity in Arabidopsis thaliana with Reduced Hsp90 Levels

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    The molecular chaperone HSP90 aids the maturation of a diverse but select set of metastable protein clients, many of which are key to a variety of signal transduction pathways. HSP90 function has been best investigated in animal and fungal systems, where inhibition of the chaperone has exceptionally diverse effects, ranging from reversing oncogenic transformation to preventing the acquisition of drug resistance. Inhibition of HSP90 in the model plant Arabidopsis thaliana uncovers novel morphologies dependent on normally cryptic genetic variation and increases stochastic variation inherent to developmental processes. The biochemical activity of HSP90 is strictly conserved between animals and plants. However, the substrates and pathways dependent on HSP90 in plants are poorly understood. Progress has been impeded by the necessity of reliance on light-sensitive HSP90 inhibitors due to redundancy in the A. thaliana HSP90 gene family. Here we present phenotypic and genome-wide expression analyses of A. thaliana with constitutively reduced HSP90 levels achieved by RNAi targeting. HSP90 reduction affects a variety of quantitative life-history traits, including flowering time and total seed set, increases morphological diversity, and decreases the developmental stability of repeated characters. Several morphologies are synergistically affected by HSP90 and growth temperature. Genome-wide expression analyses also suggest a central role for HSP90 in the genesis and maintenance of plastic responses. The expression results are substantiated by examination of the response of HSP90-reduced plants to attack by caterpillars of the generalist herbivore Trichoplusia ni. HSP90 reduction potentiates a more robust herbivore defense response. In sum, we propose that HSP90 exerts global effects on the environmental responsiveness of plants to many different stimuli. The comprehensive set of HSP90-reduced lines described here is a vital instrument to further examine the role of HSP90 as a central interface between organism, development, and environment

    ABC Transporter Pdr10 Regulates the Membrane Microenvironment of Pdr12 in Saccharomyces cerevisiae

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    The eukaryotic plasma membrane exhibits both asymmetric distribution of lipids between the inner and the outer leaflet and lateral segregation of membrane components within the plane of the bilayer. In budding yeast (Saccharomyces cerevisiae), maintenance of leaflet asymmetry requires P-type ATPases, which are proposed to act as inward-directed lipid translocases (Dnf1, Dnf2, and the associated protein Lem3), and ATP-binding cassette (ABC) transporters, which are proposed to act as outward-directed lipid translocases (Pdr5 and Yor1). The S. cerevisiae genome encodes two other Pdr5-related ABC transporters: Pdr10 (67% identity) and Pdr15 (75% identity). We report the first analysis of Pdr10 localization and function. A Pdr10-GFP chimera was located in discrete puncta in the plasma membrane and was found in the detergent-resistant membrane fraction. Compared to control cells, a pdr10∆ mutant was resistant to sorbate but hypersensitive to the chitin-binding agent Calcofluor White. Calcofluor sensitivity was attributable to a partial defect in endocytosis of the chitin synthase Chs3, while sorbate resistance was attributable to accumulation of a higher than normal level of the sorbate exporter Pdr12. Epistasis analysis indicated that Pdr10 function requires Pdr5, Pdr12, Lem3, and mature sphingolipids. Strikingly, Pdr12 was shifted to the detergent-resistant membrane fraction in pdr10∆ cells. Pdr10 therefore acts as a negative regulator for incorporation of Pdr12 into detergent-resistant membranes, a novel role for members of the ABC transporter superfamily

    On the relevance of preprocessing in predictive maintenance for dynamic systems

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    The complexity involved in the process of real-time data-driven monitoring dynamic systems for predicted maintenance is usually huge. With more or less in-depth any data-driven approach is sensitive to data preprocessing, understood as any data treatment prior to the application of the monitoring model, being sometimes crucial for the final development of the employed monitoring technique. The aim of this work is to quantify the sensitiveness of data-driven predictive maintenance models in dynamic systems in an exhaustive way. We consider a couple of predictive maintenance scenarios, each of them defined by some public available data. For each scenario, we consider its properties and apply several techniques for each of the successive preprocessing steps, e.g. data cleaning, missing values treatment, outlier detection, feature selection, or imbalance compensation. The pretreatment configurations, i.e. sequential combinations of techniques from different preprocessing steps, are considered together with different monitoring approaches, in order to determine the relevance of data preprocessing for predictive maintenance in dynamical systems
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