262 research outputs found

    Electrostatics of Colloidal Particles Confined in Nanochannels: Role of Double-Layer Interactions and Ion-Ion Correlations

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    We perform computational investigations of electrolyte-mediated interactions of charged colloidal particles confined within nanochannels. We investigate the role of discrete ion effects, valence, and electrolyte strength on colloid-wall interactions. We find for some of the multivalent charge regimes that the like-charged colloids and walls can have attractive interactions. We study in detail these interactions and the free energy profile for the colloid-wall separation. We find there are energy barriers and energy minima giving preferred colloid locations in the channel near the center and at a distance near to but separated from the channel walls. We characterize contributions from surface overcharging, condensed layers, and overlap of ion double-layers. We perform our investigations using Coarse-Grained Brownian Dynamics simulations (BD), classical Density Functional Theory (cDFT), and mean-field Poisson-Boltzmann Theory (PB). We discuss the implications of our results for phenomena in nanoscale devices.Comment: 23 figure

    Dancing Megasperm

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    Multiple, Synchronous Lesions of Differing Histology Within the Same Testis: Ultrasonographic and Pathologic Correlations

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    Objective: To describe ultrasound (US) and pathologic findings in 11 patients with multiple, synchronous lesions of different histology within the same testis. Materials and methods: We reviewed US and pathologic findings in 11 patients with multiple, synchronous lesions of different histology within the same testis. Lesions were classified as separate or adjacent one to another and attempt was made to predict tumor type on their US textures. Pathologic review assessed presence of normal tissue between adjacent lesions and of Germ Cell Neoplasia In Situ in surrounding parenchyma. Nine cases were from files specifically dedicated to testicular tumors and estimated prevalence was calculated. Results: Two nodules were seen in nine patients and 3 in remaining two. Nine had tumors of different histology; two had one malignancy and one focal benign lesion. Germ Cell Neoplasia In Situ was seen in 7/11 cases. In dedicated archives, these lesions had 1.83% prevalence. Conclusion: Multiple focal lesions identified at imaging within the testis are not always of the same histology. This can be suspected in some cases basing on US texture. Recognition that lesions are multiple and an indication of their locations within the testis is the most important role of imaging and may help pathologists correctly sample the specimen to establish nature of each of them. Presence of multiple lesions is regarded as a contraindication to testicular sparing surgery. In two of our patients, one lesion was benign. Then, when the procedure is indicated all lesions have to be sampled and assessed by pathologists before deciding between conservative or radical technique

    Professional Standards in Medical Ultrasound - EFSUMB Position Paper (Long Version) - General Aspects

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    This first position paper of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) on professional standards presents a common position across the different medical professions within EFSUMB regarding optimal standards for the performing and reporting of ultrasound examinations by any professional ultrasound operator. It describes general aspects of professionality that ensure procedure quality, effectiveness, efficiency, and sustainability in virtually all application fields of medical ultrasound. Recommendations are given related to safety and indication of ultrasound examinations, requirements for examination rooms, structured examination, systematic reporting of results, and management, communication and archiving of ultrasound data. The print version of this article is a short version. The long version is published online.publishersversionPeer reviewe

    Quantum sensing networks for the estimation of linear functions

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    The theoretical framework for networked quantum sensing has been developed to a great extent in the past few years, but there are still a number of open questions. Among these, a problem of great significance, both fundamentally and for constructing efficient sensing networks, is that of the role of inter-sensor correlations in the simultaneous estimation of multiple linear functions, where the latter are taken over a collection local parameters and can thus be seen as global properties. In this work we provide a solution to this when each node is a qubit and the state of the network is sensor-symmetric. First we derive a general expression linking the amount of inter-sensor correlations and the geometry of the vectors associated with the functions, such that the asymptotic error is optimal. Using this we show that if the vectors are clustered around two special subspaces, then the optimum is achieved when the correlation strength approaches its extreme values, while there is a monotonic transition between such extremes for any other geometry. Furthermore, we demonstrate that entanglement can be detrimental for estimating non-trivial global properties, and that sometimes it is in fact irrelevant. Finally, we perform a non-asymptotic analysis of these results using a Bayesian approach, finding that the amount of correlations needed to enhance the precision crucially depends on the number of measurement data. Our results will serve as a basis to investigate how to harness correlations in networks of quantum sensors operating both in and out of the asymptotic regime
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