1,234 research outputs found

    Incidence of central nervous system metastases in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer treated with trastuzumab: A meta-analysis

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    This study aimed to estimate the incidence of central nervous system (CNS) metastases in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) treated with trastuzumab. Studies were identified through a literature search of electronic databases. Random-effects meta-analyses were performed to estimate the incidence rate of CNS metastases, trastuzumab therapy duration, and time from trastuzumab therapy to CNS metastasis diagnosis. A meta-analysis of odds ratios was performed to evaluate the significance of a difference in CNS metastasis incidence between patients with and without trastuzumab treatment. Thirty studies (8121 trastuzumab-treated and 3972 control patients) were included. The follow-up duration was 18.9 months (95% confidence interval [CI]: 13.8, 24.1). The trastuzumab treatment duration was 9.0 months (95% CI: 7.0, 11.0). The median interval between the start of trastuzumab therapy and CNS metastasis diagnosis was 12.2 months (95% CI: 9.5, 14.7). The incidence of CNS metastasis after the start of trastuzumab therapy was 22% (95% CI: 16, 27). The incidence of CNS metastases was significantly higher in trastuzumab-treated than in non-trastuzumab-treated patients (odds ratio: 1.39 [95% CI: 1.06, 1.82], p=0.02). The survival time from the start of the study was 23.4 months (95% CI: 19.7, 27.1) in trastuzumab-treated patients and 18.4 months (95% CI: 12.7, 24.1) in patients treated with control regimens. The survival time after the development of CNS metastases in trastuzumab-treated patients was 19.2 months (95% CI: 15.6, 25.9). Approximately 22% of patients with HER2-positive MBC who were treated with trastuzumab developed CNS metastases. However, trastuzumab-treated patients had a longer survival than patients who were not treated with trastuzumab

    Spectroscopy of broad absorption line quasars at 3≲z≲53\lesssim z \lesssim 5 -- I: evidence for quasar winds shaping broad/narrow emission line regions

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    We present an observational study of 22 broad absorption line quasars (BAL QSOs) at 3≲z≲53\lesssim z \lesssim5 based on optical/near-IR spectroscopy, aiming to investigate quasar winds and their effects. The near-IR spectroscopy covers the \hb\ and/or \mgii\ broad emission lines (BELs) for these quasars, allowing us to estimate their central black hole (BH) masses in a robust way. We found that our BAL QSOs on average do not have a higher Eddington ratio than that from non-BAL QSOs matched in redshift and/or luminosity. In a subset consisting of seven strong BAL QSOs possessing sub-relativistic BAL outflows, we see the prevalence of large \civ-BEL blueshift (∼\sim3100 km sβˆ’1^{-1}) and weak \oiii\ emission (particularly the narrow \oiiiΞ»\lambda5007 component), indicative of nuclear outflows affecting the narrow emission-line (NEL) regions. In another subset consisting of thirteen BAL QSOs having simultaneous observations of \mgii\ and \hb, we found a strong correlation between 3000~\AA\ and 5000~\AA\ monochromatic luminosity, consistent with that from non-BAL QSOs matched in redshift and luminosity; however, there is no correlation between \mgii\ and \hb\ in FWHM, likely due to nuclear outflows influencing the BEL regions. Our spectroscopic investigations offer strong evidence that the presence of nuclear outflows plays an important role in shaping the BEL/NEL regions of these quasars and possibly, regulating the growth of central supermassive black holes (SMBHs). We propose that BEL blueshift and BAL could be different manifestations of the same outflow system viewed at different sightlines and/or phases.Comment: 13 pages, 10 figures. Accepted for publication in Ap

    The second-​harmonic generation in chalcogenide glass-​ceramic doped with CdS nanocrystals

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    International audienceAn innovative way is proposed here to synthesize chalcogenide glass-​CdS nanocrystal composites by hot-​pressing a combination of Ge20Sb12S68 glassy powder and nonlinear CdS nanoparticles. The cadmium sulfide nanoparticles, which possess the second-​harmonic generation property, were synthesized from basic cadmium soln. strongly complexed by amine. The obtained nanocomposites present a homogeneous distribution of the crystals. The transmission reaches 30​% at 5 ΞΌm and up to 60​% at 10.6 ΞΌm. The second-​harmonic generation at 0.9 ΞΌm has been detected. This technique can overcome the uncontrollable hetero-​crystn. which tends to occur in the glass-​ceramics prepd. by the conventional thermal treatment method

    4-[1-Acetyl-3-(4-methoxyΒ­phenΒ­yl)-2-pyrazolin-5-yl]phenol

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    In the title compound, C18H18N2O3, the dihedral angle formed by the benzene rings is 71.75β€…(4)Β°. In the crystal structure, centrosymmetrically related molΒ­ecules are linked into dimers by interΒ­molecular Oβ€”Hβ‹―O hydrogen bonds and π–π stacking interΒ­actions with centroid–centroid distances of 3.5511β€…(6)β€…Γ…

    (E)-1-(4-ChloroΒ­phenΒ­yl)-3-[4-(2,3,4,6-tetra-O-acetyl-Ξ²-d-allopyranosΒ­yloxy)phenΒ­yl]prop-2-en-1-one

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    The asymmetric unit of the title compound, C29H29ClO11, contains two independent molΒ­ecules of similar geometry, both adopting an E conformation about the C=C double bond. The dihedral angles formed by benzene rings are 10.73β€…(16) and 13.79β€…(18)Β°. The pyranΒ­oside rings adopt a chair conformation. IntraΒ­molecular Cβ€”Hβ‹―O close contacts occur. The crystal packing is stabilized by interΒ­molecular Cβ€”Hβ‹―O hydrogen bonds

    (E)-4-(Ξ²-d-AllopyranΒ­osΒ­yloxy)cinnamyl 4-bromoΒ­phenyl ketone ethanol solvate

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    The title compound, C21H21BrO7Β·C2H6O, was synthesized by the Claisen–Schimidt reaction of helicid (systematic name: 4-formylΒ­phenyl-Ξ²-d-allopyranΒ­oside) with 4-bromoΒ­acetoΒ­phenone in ethanol. The pyran ring adopts a chair conformation. In the crystal structure, molΒ­ecules are linked into a three-dimensional network by interΒ­molecular Oβ€”Hβ‹―O hydrogen bonds

    The tunneling magnetoresistance current dependence on cross sectional area, angle and temperature

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    The magnetoresistance of a MgO-based magnetic tunnel junction (MTJ) was studied experimentally. The magnetoresistance as a function of current was measured systematically on MTJs for various MgO cross sectional areas and at various temperatures from 7.5 to 290.1 K. The resistance current dependence of the MTJ was also measured for different angles between the two ferromagnetic layers. By considering particle and angular momentum conservation of transport electrons, the current dependence of magnetoresistance can be explained by the changing of spin polarization in the free magnetic layer of the MTJ. The changing of spin polarization is related to the magnetoresistance, its angular dependence and the threshold current where TMR ratio equals zero. A phenomenological model is used which avoid the complicated barrier details and also describes the data

    Skin transcriptome profiles associated with coat color in sheep

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    Background Previous molecular genetic studies of physiology and pigmentation of sheep skin have focused primarily on a limited number of genes and proteins. To identify additional genes that may play important roles in coat color regulation, Illumina sequencing technology was used to catalog global gene expression profiles in skin of sheep with white versus black coat color. Results There were 90,006 and 74,533 unigenes assembled from the reads obtained from white and black sheep skin, respectively. Genes encoding for the ribosomal proteins and keratin associated proteins were most highly expressed. A total of 2,235 known genes were differentially expressed in black versus white sheep skin, with 479 genes up-regulated and 1,756 genes down-regulated. A total of 845 novel genes were differentially expressed in black versus white sheep skin, consisting of 107 genes which were up-regulated (including 2 highly expressed genes exclusively expressed in black sheep skin) and 738 genes that were down-regulated. There was also a total of 49 known coat color genes expressed in sheep skin, from which 13 genes showed higher expression in black sheep skin. Many of these up-regulated genes, such as DCT, MATP, TYR and TYRP1, are members of the components of melanosomes and their precursor ontology category. Conclusion The white and black sheep skin transcriptome profiles obtained provide a valuable resource for future research to understand the network of gene expression controlling skin physiology and melanogenesis in sheep

    Multi-color Optical Variability of the TeV Blazar Mrk 501 in the Low-State

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    We report results based on the monitoring of the BL Lac object Mrk 501 in the optical (B, V and R) passbands from March to May 2000. Observations spread over 12 nights were carried out using 1.2 meter Mount Abu Telescope, India and 61 cm Telescope at Sobaeksan Astronomy Observatory, South Korea. The aim is to study the intra-day variability (IDV), short term variability and color variability in the low state of the source. We have detected flux variation of 0.05 mag in the R-band in time scale of 15 min in one night. In the B and V passbands, we have less data points and it is difficult to infer any IDVs. Short term flux variations are also observed in the V and R bands during the observing run. No significant variation in color (Bβˆ’-R) has been detected but (Vβˆ’-R) shows variation during the present observing run. Assuming the shortest observed time scale of variability (15 min) to represent the disk instability or pulsation at a distance of 5 Schwarschild radii from the black hole (BH), mass of the central BH is estimated ∼\sim 1.20 Γ—\times 108MβŠ™^{8} M_{\odot}.Comment: 4 figures, 4 tables, Accepted for publication in New Astronom

    SDSS J013127.34βˆ’-032100.1: A newly discovered radio-loud quasar at z=5.18z=5.18 with extremely high luminosity

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    Only very few z>5 quasars discovered to date are radio-loud, with a radio-to-optical flux ratio (radio-loudness parameter) higher than 10. Here we report the discovery of an optically luminous radio-loud quasar, SDSS J013127.34-032100.1 (J0131-0321 in short), at z=5.18+-0.01 using the Lijiang 2.4m and Magellan telescopes. J0131-0321 has a spectral energy distribution consistent with that of radio-loud quasars. With an i-band magnitude of 18.47 and radio flux density of 33 mJy, its radio-loudness parameter is ~100. The optical and near-infrared spectra taken by Magellan enable us to estimate its bolometric luminosity to be L_bol ~ 1.1E48 erg/s, approximately 4.5 times greater than that of the most distant quasar known to date. The black hole mass of J0131-0321 is estimated to be 2.7E9 solar masses, with an uncertainty up to 0.4 dex. Detailed physical properties of this high-redshift, radio-loud, potentially super-Eddington quasar can be probed in the future with more dedicated and intensive follow-up observations using multi-wavelength facilities.Comment: 5 pages, 3 figures, accepted to ApJ
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