472 research outputs found

    Imatinib Resistance and Relapse in CML Patients with Complex Chromosomal Variants

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    The BCR-ABL tyrosine kinase inhibitor Imatinib is highly effective for chronic myeloid leukemia (CML). However, some patients gradually develop resistance to Imatinib, resulting in therapeutic failure. In the present study, we analyzed 192 CML patients, from which CML relapse was observed in 17 individuals with involvement of other chromosomes in addition to Philadelphia translocation and who were on treatment of Imatinib (400mg per day since last 3-4 years). Interestingly, all 17 individuals had only BCR/ABL fusion at the time of diagnosis and attained complete Cytogenetic and hematological remission (CHR) within 18 weeks of the therapy. Three individuals among these 17 were not regular in the uptake of Imatinib after attaining CHR and CCyR and could be probable reason for relapse. In addition, we have also recorded primary resistance to Imatinib in 4 individuals who were diagnosed with some complex chromosomal variants. Therefore, either involvement of other genes along with BCR/ABL fusion, or additional chromosomes and point mutation in the fusion BCR/ABL gene itself could be a reason for primary resistance and relapse to Imatinib

    Temperature mapping of stacked silicon dies from x-ray diffraction intensities

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    Increasing power densities in integrated circuits has led to an increased prevalence of thermal hotspots in integrated circuits. Tracking these thermal hotspots is imperative to prevent circuit failures. In 3D integrated circuits, conventional surface techniques like infrared thermometry are unable to measure 3D temperature distribution and optical and magnetic resonance techniques are difficult to apply due to the presence of metals and large current densities. X-rays offer high penetration depth and can be used to probe 3D structures. We report a method utilizing the temperature dependence of x-rays diffraction intensity via the Debye-Waller factor to simultaneously map the temperature of an individual silicon die that is a part of a stack of dies. Utilizing beamline 1-ID-E at the Advanced Photon Source (Argonne), we demonstrate for each individual silicon die, a temperature resolution of 3 K, a spatial resolution of 100 um x 400 um and a temporal resolution of 20 s. Utilizing a sufficiently high intensity laboratory source, e.g., from a liquid anode source, this method can be scaled down to laboratories for non-invasive temperature mapping of 3D integrated circuits

    Quantum error-correcting codes and 4-dimensional arithmetic hyperbolic manifolds

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    Using 4-dimensional arithmetic hyperbolic manifolds, we construct some new homological quantum error correcting codes. They are LDPC codes with linear rate and distance nϵn^\epsilon. Their rate is evaluated via Euler characteristic arguments and their distance using Z2\mathbb{Z}_2-systolic geometry. This construction answers a queston of Z\'emor, who asked whether homological codes with such parameters could exist at all.Comment: 21 page

    Extragalactic sources with asymmetric radio structure I. Observations of 17 sources

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    We present total-intensity and linear-polarization observations with the Very Large Array (VLA) at λ6 and 2 cm of 17 sources, almost all of which were suspected to have extended emission only on one side of the nucleus. Five of them are still one-sided, three appear unresolved, while seven have radio lobes on both sides of the nucleus. The outer components in the double-lobed sources, however, have significantly different surface brightness or are very asymmetrically located with respect to the nucleus

    Electrochemical heavy metal detection, photocatalytic, photoluminescence, biodiesel production and antibacterial activities of Ag�ZnO nanomaterial

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    Zinc oxide nanoparticles (ZnO Nps) and silver doped zinc oxide nanoparticles (Ag�ZnO Nps) were prepared using nitrates of zinc and silver as oxidizers and succinic acid as a fuel through solution combustion synthesis (SCS) at 400 °C. The synthesized materials were characterized by various analytical techniques such as XRD, FTIR, Raman UV�vis, PL, SEM, EDX and TEM. The synthesized nanomaterials were tested for the photocatalytic degradation of methylene blue and the result reveal that Ag�ZnO Nps shows the better photocatalytic activity compared to undoped ZnO Nps. Biodiesel production from Simarouba oil shows that Ag�ZnO Nps acts as good catalyst compare to ZnO Nps, we have also developed sensor which showed a linearity in the concentration range 50�350 nM and limit of detection was found to be 3.5 and 3.8 nM (3�) for lead and cadmium respectively. Further we have examined the antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. © 2017 Elsevier Lt

    Time dependence of Bragg forward scattering and self-seeding of hard x-ray free-electron lasers

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    Free-electron lasers (FELs) can now generate temporally short, high power x-ray pulses of unprecedented brightness, even though their longitudinal coherence is relatively poor. The longitudinal coherence can be potentially improved by employing narrow bandwidth x-ray crystal optics, in which case one must also understand how the crystal affects the field profile in time and space. We frame the dynamical theory of x-ray diffraction as a set of coupled waves in order to derive analytic expressions for the spatiotemporal response of Bragg scattering from temporally short incident pulses. We compute the profiles of both the reflected and forward scattered x-ray pulses, showing that the time delay of the wave τ\tau is linked to its transverse spatial shift Δx\Delta x through the simple relationship Δx=cτcotθ\Delta x = c\tau \cot\theta, where θ\theta is the grazing angle of incidence to the diffracting planes. Finally, we apply our findings to obtain an analytic description of Bragg forward scattering relevant to monochromatically seed hard x-ray FELs.Comment: 11 pages, 6 figure

    The Nuclear Reddening Curve for Active Galactic Nuclei and the Shape of the Infra-Red to X-Ray Spectral Energy Distribution

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    We present extinction curves derived from the broad emission lines and continua of large samples of both radio-loud and radio-quiet AGNs. The curves are significantly flatter in the UV than are curves for the local ISM. The reddening curves for the radio-quiet LBQS quasars are slightly steeper than those of the radio-loud quasars in the UV, probably because of additional reddening by dust further out in the host galaxies of the former. The UV extinction curves for the radio-loud AGNs are very flat. This is explicable with slight modifications to standard MRN dust models: there is a relative lack of small grains in the nuclear dust. Our continuum and broad-emission line reddening curves agree in both shape and amplitude, confirming that the continuum shape is indeed profoundly affected by reddening for all but the bluest AGNs. With correction by our generic extinction curve, all of the radio-loud AGNs have continuous optical-UV spectra consistent with a single shape. We show that radio-quiet AGNs have very similar intrinsic UV to optical shape over orders of magnitude in luminosity. We also argue that radio-loud and radio-quiet AGNs probably share the same underlying continuum shape and that most of the systematic differences between their observed continuum shapes are due to higher nuclear reddening in radio-selected AGNs, and additional reddening from dust further out in the host galaxies in radio-quiet AGNs. Our conclusions have important implications for the modelling of quasar continua and the analysis of quasar demographics.Comment: 41 pages, including 6 figures and 3 tables. To appear in ApJ vol. 614, October 20 issue. Some slight wording changes. Some additional references added. Small changes in the model fit in section 6.2, to the analytical fit in the Appendix, and to the tabulated reddening curve in the Appendi

    A High Energy X-Ray and Neutron Scattering Study of Iron Phosphate Glasses Containing Uranium

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    The atomic structure of iron phosphate glasses containing uranium has been studied by complementary neutron and x-ray scattering techniques. by combining x-ray and neutron structure factors, detailed information about different pair interactions has been obtained. Most of the basic structural features such as coordination numbers and O-O and P-O distances in uranium containing glasses are the same as those in the base glass of batch composition 40Fe2O3-60P2O5 (mol %). However, the Fe-O distances change slightly with the addition of uranium. The observed structural parameters support a structural model in which the waste elements occupy voids in the Fe-O-P network, hence, not altering the basic structure of the parent iron phosphate glass

    Polyhedral units and network connectivity in calcium aluminosilicate glasses from high-energy x-ray diffraction

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    Structure factors for Cax/2AlxSi1-xO2 glasses (x=0,0.25,0.5,0.67) extended to a wave vector of magnitude Q= 40 1/A have been obtained by high-energy x-ray diffraction. For the first time, it is possible to resolve the contributions of Si-O, Al-O and Ca-O coordination polyhedra to the experimental atomic pair distribution functions (PDF). It has been found that both Si and Al are four-fold coordinated and so participate in a continuous tetrahedral network at low values of x. The number of network breaking defects in the form of non-bridging oxygens (NBO's) increases slowly with x until x=0.5 (NBO's ~ 10% at x=0.5). By x=0.67 the network breaking defects become significant as evidenced by the significant drop in the average coordination number of Si. By contrast, Al-O tetrahedra remain free of NBO's and fully integrated in the Al/Si-O network for all values of x. Calcium maintains a rather uniform coordination sphere of approximately 5 oxygen atoms for all values of x. The results suggest that not only Si/Al-O tetrahedra but Ca-O polyhedra, too, play a role in determining the glassy structure
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