157 research outputs found

    Quantum Hydrodynamic Model for the enhanced moments of Inertia of molecules in Helium Nanodroplets: Application to SF6_6

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    The increase in moment of inertia of SF6_6 in helium nanodroplets is calculated using the quantum hydrodynamic approach. This required an extension of the numerical solution to the hydrodynamic equation to three explicit dimensions. Based upon an expansion of the density in terms of the lowest four Octahedral spherical harmonics, the predicted increase in moment of inertia is 170uA˚2170 {\rm u \AA^2}, compared to an experimentally determined value of 310(10)uA˚2310(10) {\rm u \AA^2}, i.e., 55% of the observed value. The difference is likely in at least part due to lack of convergence with respect to the angular expansion, but at present we do not have access to the full densities from which a higher order expansion can be determined. The present results contradict those of Kwon et al., J. Chem. Phys. {\bf 113}, 6469 (2000), who predicted that the hydrodynamic theory predicted less than 10% of the observed increase in moment of inertia.Comment: 10 pages, including 1 figur

    A Novel Data Fusion Technique for Snow Cover Retrieval

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    © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.This paper presents a novel data fusion technique for improving the snow cover monitoring for a mesoscale Alpine region, in particular in those areas where two information sources disagree. The presented methodological innovation consists in the integration of remote-sensing data products and the numerical simulation results by means of a machine learning classifier (support vector machine), capable to extract information from their quality measures. This differs from the existing approaches where remote sensing is only used for model tuning or data assimilation. The technique has been tested to generate a time series of about 1300 snow maps for the period between October 2012 and July 2016. The results show an average agreement between the fused product and the reference ground data of 96%, compared to 90% of the moderate-resolution imaging spectroradiometer (MODIS) data product and 92% of the numerical model simulation. Moreover, one of the most important results is observed from the analysis of snow cover area (SCA) time series, where the fused product seems to overcome the well-known underestimation of snow in forest of the MODIS product, by accurately reproducing the SCA peaks of winter season

    Helium nanodroplet isolation ro-vibrational spectroscopy: methods and recent results

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    In this article, recent developments in HElium NanoDroplet Isolation (HENDI) spectroscopy are reviewed, with an emphasis on the infrared region of the spectrum. Topics discussed include experimental details, comparison of radiation sources, symmetry issues of the helium solvation structure, sources of line broadening, changes in spectroscopic constants upon solvation, and applications including formation of novel chemical structures.Comment: 24 pages, 8 figures, 3 tables; to be published in the Journal of Chemical Physic

    Three-Dimensional Shapes of Spinning Helium Nanodroplets

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    A significant fraction of superfluid helium nanodroplets produced in a free-jet expansion have been observed to gain high angular momentum resulting in large centrifugal deformation. We measured single-shot diffraction patterns of individual rotating helium nanodroplets up to large scattering angles using intense extreme ultraviolet light pulses from the FERMI free-electron laser. Distinct asymmetric features in the wide-angle diffraction patterns enable the unique and systematic identification of the three-dimensional droplet shapes. The analysis of a large dataset allows us to follow the evolution from axisymmetric oblate to triaxial prolate and two-lobed droplets. We find that the shapes of spinning superfluid helium droplets exhibit the same stages as classical rotating droplets while the previously reported metastable, oblate shapes of quantum droplets are not observed. Our three-dimensional analysis represents a valuable landmark for clarifying the interrelation between morphology and superfluidity on the nanometer scale

    miR-181b as a therapeutic agent for chronic lymphocytic leukemia in the Eμ-TCL1 mouse model

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    The involvement of microRNAs (miRNAs) in chronic lymphocytic leukemia (CLL) pathogenesis suggests the possibility of anti-CLL therapeutic approaches based on miRNAs. Here, we used the Eµ-TCL1 transgenic mouse model, which reproduces leukemia with a similar course and distinct immunophenotype as human B-CLL, to test miR-181b as a therapeutic agent.In vitro enforced expression of miR-181b mimics induced significant apoptotic effects in human B-cell lines (RAJI, EHEB), as well as in mouse Eµ-TCL1 leukemic splenocytes. Molecular analyses revealed that miR-181b not only affected the expression of TCL1, Bcl2 and Mcl1 anti-apoptotic proteins, but also reduced the levels of Akt and phospho-Erk1/2. Notably, a siRNA anti-TCL1 could similarly down-modulate TCL1, but exhibited a reduced or absent activity in other relevant proteins, as well as a reduced effect on cell apoptosis and viability. In vivo studies demonstrated the capability of miR-181b to reduce leukemic cell expansion and to increase survival of treated mice.These data indicate that miR-181b exerts a broad range of actions, affecting proliferative, survival and apoptotic pathways, both in mice and human cells, and can potentially be used to reduce expansion of B-CLL leukemic cells

    Experimental Analysis of ViLTE Service

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    Long-term evolution (LTE) is a broadband wireless cellular system currently available in about 200 countries. From the mobile network operator point of view, one of the most appealing characteristics of LTE is the possibility of providing the users with mobile broadband services like voice over LTE and video over LTE (ViLTE), with strict quality of service (QoS) guarantees. The success of such services, which usually require a subscription fee, is obviously tightly bound to the users' quality of experience (QoE), that must be significantly better than the quality perceived in case of free services. This paper attempts to evaluate the perceived quality of the ViLTE service. In more detail, we present the results of an experimental test–bed realised at one of the most popular italian MNO, aimed at evaluating the impact of several network layer QoS parameters on the QoE of the ViLTE service

    Renal amyloid‐A amyloidosis in cats: Characterization of proteinuria and biomarker discovery, and associations with kidney histology

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    BackgroundAmyloid A (AA) amyloidosis is a protein misfolding disease arising from serum amyloid A (SAA). Systemic AA amyloidosis recently was shown to have a high prevalence in shelter cats in Italy and was associated with azotemia and proteinuria.ObjectivesInvestigate urine protein profiles and diagnostic biomarkers in cats with renal AA amyloidosis.AnimalsTwenty‐nine shelter cats.MethodsCase‐control study. Cats with renal proteinuria that died or were euthanized between 2018 and 2021 with available necropsy kidney, liver and spleen samples, and with surplus urine collected within 30 days before death, were included. Histology was used to characterize renal damage and amyloid amount and distribution; immunohistochemistry was used to confirm AA amyloidosis. Urine protein‐to‐creatinine (UPC) and urine amyloid A‐to‐creatinine (UAAC) ratios were calculated, and sodium dodecyl sulfate‐agarose gel electrophoresis (SDS‐AGE) and liquid chromatography‐mass spectrometry (LC‐MS) of proteins were performed.ResultsTwenty‐nine cats were included. Nineteen had AA amyloidosis with renal involvement. Cats with AA amyloidosis had a higher UPC (median, 3.9; range, 0.6‐12.7 vs 1.5; 0.6‐3.1; P = .03) and UAAC ratios (median, 7.18 × 103^{−3}; range, 23 × 103^{−3}‐21.29 × 103^{−3} vs 1.26 × 103^{−3}; 0.21 × 103^{−3}‐6.33 × 103^{−3}; P = .04) than unaffected cats. The SDS‐AGE identified mixed‐type proteinuria in 89.4% of cats with AA amyloidosis and in 55.6% without AA amyloidosis (P = .57). The LC‐MS identified 63 potential biomarkers associated with AA amyloidosis (P < .05). Among these, urine apolipoprotein C‐III was higher in cats with AA amyloidosis (median, 1.38 × 107^{7}; range, 1.85 × 105^{5}‐5.29 × 107^{7} vs 1.76 × 106^{6}; 0.0 × 100^{0}‐1.38 × 107^{7}; P = .01). In the kidney, AA‐amyloidosis was associated with glomerulosclerosis (P = .02) and interstitial fibrosis (P = .05).Conclusions and Clinical ImportanceRenal AA amyloidosis is associated with kidney lesions, increased proteinuria and increased urine excretion of SAA in shelter cats. Additional studies are needed to characterize the role of lipid transport proteins in the urine of affected cats
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