642 research outputs found

    Observations of breakup processes of liquid jets using real-time X-ray radiography

    Get PDF
    To unravel the liquid-jet breakup process in the nondilute region, a newly developed system of real-time X-ray radiography, an advanced digital image processor, and a high-speed video camera were used. Based upon recorded X-ray images, the inner structure of a liquid jet during breakup was observed. The jet divergence angle, jet breakup length, and fraction distributions along the axial and transverse directions of the liquid jets were determined in the near-injector region. Both wall- and free-jet tests were conducted to study the effect of wall friction on the jet breakup process

    Gegenbauer-solvable quantum chain model

    Full text link
    In an innovative inverse-problem construction the measured, experimental energies E1E_1, E2E_2, ...ENE_N of a quantum bound-state system are assumed fitted by an N-plet of zeros of a classical orthogonal polynomial fN(E)f_N(E). We reconstruct the underlying Hamiltonian HH (in the most elementary nearest-neighbor-interaction form) and the underlying Hilbert space H{\cal H} of states (the rich menu of non-equivalent inner products is offered). The Gegenbauer's ultraspherical polynomials fn(x)=Cnα(x)f_n(x)=C_n^\alpha(x) are chosen for the detailed illustration of technicalities.Comment: 29 pp., 1 fi

    Anomalous double peak structure in Nb/Ni superconductor/ferromagnet tunneling DOS

    Full text link
    We have experimentally investigated the density of states (DOS) in Nb/Ni (S/F) bilayers as a function of Ni thickness, dFd_F. Our thinnest samples show the usual DOS peak at ±Δ0\pm\Delta_0, whereas intermediate-thickness samples have an anomalous ``double-peak'' structure. For thicker samples (dF≄3.5d_F \geq 3.5 nm), we see an ``inverted'' DOS which has previously only been reported in superconductor/weak-ferromagnet structures. We analyze the data using the self-consistent non-linear Usadel equation and find that we are able to quantitatively fit the features at ±Δ0\pm\Delta_0 if we include a large amount of spin-orbit scattering in the model. Interestingly, we are unable to reproduce the sub-gap structure through the addition of any parameter(s). Therefore, the observed anomalous sub-gap structure represents new physics beyond that contained in the present Usadel theory.Comment: 4 pages, 3 figure

    A survey of pediatric hematology/oncology specialists regarding management of central line associated venous thrombosis

    Full text link
    Central venous catheters (CVCs) account for the largest proportion of thrombotic events in pediatric patients. Questions remain regarding adequate treatment and prevention methods. We surveyed pediatric hematology/oncology specialists, using hypothetical cases to assess management strategies for acute CVC thrombosis and secondary prevention. Survey respondents varied in the use of the thrombophilia evaluation (33.3%, 41/123) and duration of treatment (6 weeks: 54.1%, 66/122). Secondary CVC prophylaxis was utilized by 36.6% (45/123) of respondents and by 24.4% (30/123) but only if there was a documented thrombophilia. This heterogeneity highlights the need for clinical studies to address these important clinical questions.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137422/1/pbc26383_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137422/2/pbc26383.pd

    Synthesis and Assembly of Dipolar Heterostructured Tetrapods: Colloidal Polymers with “Giant tert-butyl” Groups

    Get PDF
    We report on the first synthesis of a heterostructured semiconductor tetrapod from CdSe@CdS that carries a single dipolar nanoparticle tip from a core–shell colloid of Au@Co. A four-step colloidal total synthesis was developed, where the key step in the synthesis was the selective deposition of a single AuNP tip onto a CdSe@CdS tetrapod under UV-irradiation. Synthetic accessibility to this dipolar heterostructured tetrapod enabled the use of these as colloidal monomers to form colloidal polymers that carry the semiconductor tetrapod as a side chain group attached to the CoNP colloidal polymer main chain. The current report details a number of novel discoveries on the selective synthesis of an asymmetric heterostructured tetrapod that is capable of 1D dipolar assembly into colloidal polymers that carry tetrapods as side chain groups that mimic “giant tert-butyl groups”

    Increased cytoplasmatic expression of cancer immune surveillance receptor CD1d in anaplastic thyroid carcinomas

    Get PDF
    Background Anaplastic thyroid carcinomas are associated with rapid tumor growth, short survival time and without any promising therapy to improve the poor prognosis. In this study, expression of immunoregulative receptor CD1d and lymphocyte infiltration in different thyroid tumors as well as in healthy tissue were analyzed in order to find new targets for an immunotherapeutic approach. Methods CD1d immunohistochemistry was performed in samples of 18 anaplastic, 17 follicular, 27 papillary, and 4 medullary thyroid carcinomas as well as in 19 specimens from normal thyroid tissue and additionally in 10 samples of sarcoma, seven malignant melanoma and three spindle-cell lung carcinoma. Furthermore, thyroid samples were stained with antibodies against CD3, CD20, CD56, CD68, and LCA in order to analyze lymphocyte infiltration. Results For the first time CD1d receptor expression on normal thyroid tissue could be demonstrated. Moreover, anaplastic thyroid carcinomas showed significantly higher expression levels compared to other thyroid samples. Most astonishingly, CD1d expression disappeared from the cellular surface and was detected rather in the cytoplasm of anaplastic thyroid carcinoma cells. In addition, histologically similar tumors to anaplastic carcinoma like sarcoma and malignant melanoma revealed distinct CD1d staining patterns. Furthermore, infiltration of T cells, B cells, and macrophages in anaplastic thyroid carcinomas was different when compared to normal thyroid tissue and all other thyroid carcinomas. Conclusions Anaplastic thyroid carcinomas show significantly higher expression of CD1d, a receptor for NKT cells, which are subject of several anticancer therapy studies. These results may offer a novel approach to explore immunotherapeutic treatment options

    Localization transition of random copolymers at interfaces

    Full text link
    We consider adsorption of random copolymer chains onto an interface within the model of Garel et al. Europhysics Letters 8, 9 (1989). By using the replica method the adsorption of the copolymer at the interface is mapped onto the problem of finding the ground state of a quantum mechanical Hamiltonian. To study this ground state we introduce a novel variational principle for the Green's function, which generalizes the well-known Rayleigh-Ritz method of Quantum Mechanics to nonstationary states. Minimization with an appropriate trial Green's function enables us to find the phase diagram for the localization-delocalization transition for an ideal random copolymer at the interface.Comment: 5 page

    PT-symetrically regularized Eckart,Poeschl-Teller and Hulthen potentials

    Full text link
    Version 1: The well known Eckart's singular s-wave potential is PT-symmetrically regularized and continued to the whole real line. The new model remains exactly solvable and its bound states remain proportional to Jacobi polynomials. Its real and discrete spectrum exhibits several unusual features. Version 2: Parity times time-reversal symmetry of complex Hamiltonians with real spectra is usually interpreted as a weaker mathematical substitute for Hermiticity. Perhaps an equally important role is played by the related strengthened analyticity assumptions. In a constructive illustration we complexify a few potentials solvable only in s-wave. Then we continue their domain from semi-axis to the whole axis and get the new exactly solvable models. Their energies come out real as expected. The new one-dimensional spectra themselves differ quite significantly from their s-wave predecessors.Comment: Original 10-page letter ``PT-symmetrized exact solution of the singular Eckart oscillator" is extended to a full pape

    Observational Limits on Machos in the Galactic Halo

    Get PDF
    We present final results from the first phase of the EROS search for gravitational microlensing of stars in the Magellanic Clouds by unseen deflectors (machos: MAssive Compact Halo Objects). The search is sensitive to events with time scales between 15 minutes and 200 days corresponding to deflector masses in the range 1.e-7 to a few solar masses. Two events were observed that are compatible with microlensing by objects of mass of about 0.1 Mo. By comparing the results with the expected number of events for various models of the Galaxy, we conclude that machos in the mass range [1.e-7, 0.02] Mo make up less than 20% (95% C.L.) of the Halo dark matter.Comment: 4 pages, 3 Postscript figures, to be published in Astronomy & Astrophysic
    • 

    corecore