1,828 research outputs found
Shining Emitter in a Stable Host: Design of Halide Perovskite Scintillators for X-ray Imaging from Commercial Concept
Halide perovskite (HP) nanocrystals (NCs) have recently shown great potential for X-ray detection and imaging. However, the practical application still has a long way to go with many technical requirements waiting to be fulfilled, including structure optimization, stability enhancement, and cost reduction. A design principle in this beginning stage is urgently needed but still lacking. Herein, with an āemitter-in-matrixā principle refined from commercial scintillators, CsPbBr3@Cs4PbBr6 with emissive CsPbBr3 NCs embedded inside a solid-state Cs4PbBr6 host is subjected to X-ray sensing and imaging. The Cs4PbBr6 matrix not only enhances the attenuation of X-rays but also dramatically improves the stability of CsPbBr3 NCs. A favorable optical design with the Cs4PbBr6 matrix being transparent to the emission from CsPbBr3 NCs enables efficient light output. As a result, stable and sensitive scintillation response to X-ray signals is demonstrated with superior linearity and ultrahigh time resolution. In order to show the huge potential for practical applications, X-ray imaging using a large-area film (360 mm Ć 240 mm) by the blade-coating technique is carried out to obtain a high-quality image of interior structures invisible to the human eye. In addition to the above advantages in optics, CsPbBr3@Cs4PbBr6 also enjoys facile solution synthesis with large scalability, excellent repeatability, and low cost
Bright single-photon sources in bottom-up tailored nanowires
The ability to achieve near-unity light extraction efficiency is necessary
for a truly deterministic single photon source. The most promising method to
reach such high efficiencies is based on embedding single photon emitters in
tapered photonic waveguides defined by top-down etching techniques. However,
light extraction efficiencies in current top-down approaches are limited by
fabrication imperfections and etching induced defects. The efficiency is
further tempered by randomly positioned off-axis quantum emitters. Here, we
present perfectly positioned single quantum dots on the axis of a tailored
nanowire waveguide using bottom-up growth. In comparison to quantum dots in
nanowires without waveguide, we demonstrate a 24-fold enhancement in the single
photon flux, corresponding to a light extraction efficiency of 42 %. Such high
efficiencies in one-dimensional nanowires are promising to transfer quantum
information over large distances between remote stationary qubits using flying
qubits within the same nanowire p-n junction.Comment: 19 pages, 6 figure
Shot Noise in Mesoscopic Diffusive Andreev Wires
We study shot noise in mesoscopic diffusive wires between a normal and a
superconducting terminal. We particularly focus on the regime, in which the
proximity-induced reentrance effect is important. We will examine the
difference between a simple Boltzmann-Langevin description, which neglects
induced correlations beyond the simple conductivity correction, and a full
quantum calculation. In the latter approach, it turns out that two Andreev
pairs propagating coherently into the normal metal are anti-correlated for
E<E_c, where E_c=D/L^2 is the Thouless energy. In a fork geometry the
flux-sensitive suppression of the effective charge was confirmed
experimentally.Comment: 12 pages, proceedings of the NATO ARW MQO, Bled, Sloveni
Poly(ADP-ribose) polymerase family member 14 (PARP14) is a novel effector of the JNK2-dependent pro-survival signal in multiple myeloma
Copyright @ 2013 Macmillan Publishers Limited. This is the author's accepted manuscript. The final published article is available from the link below.Regulation of cell survival is a key part of the pathogenesis of multiple myeloma (MM). Jun N-terminal kinase (JNK) signaling has been implicated in MM pathogenesis, but its function is unclear. To elucidate the role of JNK in MM, we evaluated the specific functions of the two major JNK proteins, JNK1 and JNK2. We show here that JNK2 is constitutively activated in a panel of MM cell lines and primary tumors. Using loss-of-function studies, we demonstrate that JNK2 is required for the survival of myeloma cells and constitutively suppresses JNK1-mediated apoptosis by affecting expression of poly(ADP-ribose) polymerase (PARP)14, a key regulator of B-cell survival. Strikingly, we found that PARP14 is highly expressed in myeloma plasma cells and associated with disease progression and poor survival. Overexpression of PARP14 completely rescued myeloma cells from apoptosis induced by JNK2 knockdown, indicating that PARP14 is critically involved in JNK2-dependent survival. Mechanistically, PARP14 was found to promote the survival of myeloma cells by binding and inhibiting JNK1. Moreover, inhibition of PARP14 enhances the sensitization of MM cells to anti-myeloma agents. Our findings reveal a novel regulatory pathway in myeloma cells through which JNK2 signals cell survival via PARP14, and identify PARP14 as a potential therapeutic target in myeloma.Kay Kendall Leukemia Fund, NIH, Cancer Research UK, Italian Association for Cancer Research and the Foundation for Liver Research
Clinical, Virological and Immunological Features from Patients Infected with Re-Emergent Avian-Origin Human H7N9 Influenza Disease of Varying Severity in Guangdong Province
The second wave of avian influenza H7N9 virus outbreak in humans spread to the Guangdong province of China by August of 2013 and this virus is now endemic in poultry in this region.Background
The second wave of avian influenza H7N9 virus outbreak in humans spread to the Guangdong province of China by August of 2013 and this virus is now endemic in poultry in this region.
Methods
Five patients with H7N9 virus infection admitted to our hospital during August 2013 to February 2014 were intensively investigated. Viral load in the respiratory tract was determined by quantitative polymerase chain reaction (Q-PCR) and cytokine levels were measured by bead-based flow cytometery.
Results
Four patients survived and one died. Viral load in different clinical specimens was correlated with cytokine levels in plasma and broncho-alveolar fluid (BALF), therapeutic modalities used and clinical outcome. Intravenous zanamivir appeared to be better than peramivir as salvage therapy in patients who failed to respond to oseltamivir. Higher and more prolonged viral load was found in the sputum or endotracheal aspirates compared to throat swabs. Upregulation of proinflammatory cytokines IP-10, MCP-1, MIG, MIP-1Ī±/Ī², IL-1Ī² and IL-8 was found in the plasma and BALF samples. The levels of cytokines in the plasma and viral load were correlated with disease severity. Reactivation of herpes simplex virus type 1(HSV-1) was found in three out of five patients (60%).
Conclusion
Expectorated sputum or endotracheal aspirate specimens are preferable to throat swabs for detecting and monitoring H7N9 virus. Severity of the disease was correlated to the viral load in the respiratory tract as well as the extents of cytokinemia. Reactivation of HSV-1 may contribute to clinical outcome.published_or_final_versio
Centralizer's applications to the (b, c)-inverses in rings
[EN] We give several conditions in order that the absorption law for one sided (b,c)-inverses in rings holds. Also, by using centralizers, we obtain the absorption law for the (b,c)-inverse and the reverse order law of the (b,c)-inverse in rings. As applications, we obtain the related results for the inverse along an element, Moore-Penrose inverse, Drazin inverse, group inverse and core inverse.This research is supported by the National Natural Science Foundation of China (no. 11771076 and no. 11871301). The first author is grateful to China Scholarship Council for giving him a scholarship for his further study in Universitat Politecnica de Valencia, Spain.Xu, S.; Chen, J.; BenĆtez LĆ³pez, J.; Wang, D. (2019). Centralizer's applications to the (b, c)-inverses in rings. Revista de la Real Academia de Ciencias Exactas, FĆsicas y Naturales. 113(3):1739-1746. https://doi.org/10.1007/s13398-018-0574-0S173917461133Baksalary, O.M., Trenkler, G.: Core inverse of matrices. Linear Multilinear Algebra 58(6), 681ā697 (2010)BenĆtez, J., Boasso, E.: The inverse along an element in rings with an involution, Banach algebras and C ā -algebras. Linear Multilinear Algebra 65(2), 284ā299 (2017)BenĆtez, J., Boasso, E., Jin, H.W.: On one-sided ( B , C ) -inverses of arbitrary matrices. Electron. J. Linear Algebra 32, 391ā422 (2017)Boasso, E., KantĆŗn-Montiel, G.: The ( b , c ) -inverses in rings and in the Banach context. Mediterr. J. Math. 14, 112 (2017)Chen, Q.G., Wang, D.G.: A class of coquasitriangular Hopf group algebras. Comm. Algebra 44(1), 310ā335 (2016)Chen, J.L., Ke, Y.Y., MosiÄ, D.: The reverse order law of the ( b , c ) -inverse in semigroups. Acta Math. Hung. 151(1), 181ā198 (2017)Deng, C.Y.: Reverse order law for the group inverses. J. Math. Anal. Appl. 382(2), 663ā671 (2011)Drazin, M.P.: Pseudo-inverses in associative rings and semigroups. Am. Math. Mon. 65, 506ā514 (1958)Drazin, M.P.: A class of outer generalized inverses. Linear Algebra Appl. 436, 1909ā1923 (2012)Drazin, M.P.: Left and right generalized inverses. Linear Algebra Appl. 510, 64ā78 (2016)Jin, H.W., BenĆtez, J.: The absorption laws for the generalized inverses in rings. Electron. J. Linear Algebra 30, 827ā842 (2015)Johnson, B.E.: An introduction to the theory of centralizers. Proc. Lond. Math. Soc. 14, 299ā320 (1964)Ke, Y.Y., CvetkoviÄ-IliÄ, D.S., Chen, J.L., ViÅ”njiÄ, J.: New results on ( b , c ) -inverses. Linear Multilinear Algebra 66(3), 447ā458 (2018)Ke Y.Y., ViÅ”njiÄ J., Chen J.L.: One sided ( b , c ) -inverse in rings (2016). arXiv:1607.06230v1Liu, X.J., Jin, H.W., CvetkoviÄ-IliÄ, D.S.: The absorption laws for the generalized inverses. Appl. Math. Comput. 219, 2053ā2059 (2012)Mary, X.: On generalized inverse and Greenās relations. Linear Algebra Appl. 434, 1836ā1844 (2011)Mary, X., PatrĆcio, P.: Generalized inverses modulo H in semigroups and rings. Linear Multilinear Algebra 61(8), 1130ā1135 (2013)MosiÄ, D., CvetkoviÄ-IliÄ, D.S.: Reverse order law for the Moore-Penrose inverse in C ā -algebras. Electron. J. Linear Algebra 22, 92ā111 (2011)RakiÄ, D.S.: A note on Rao and Mitraās constrained inverse and Drazinās ( b , c ) -inverse. Linear Algebra Appl. 523, 102ā108 (2017)RakiÄ, D.S., DinÄiÄ, N.Ä., DjordjeviÄ, D.S.: Group, MooreāPenrose, core and dual core inverse in rings with involution. Linear Algebra Appl. 463, 115ā133 (2014)Wang, L., Castro-GonzĆ”lez, N., Chen, J.L.: Characterizations of outer generalized inverses. Can. Math. Bull. 60(4), 861ā871 (2017)Wei, Y.M.: A characterization and representation of the generalized inverse A T , S ( 2 ) and its applications. Linear Algebra Appl. 280, 87ā96 (1998)Xu, S.Z., BenĆtez, J.: Existence criteria and expressions of the ( b , c ) -inverse in rings and its applications. Mediterr. J. Math. 15, 14 (2018)Zhu, H.H., Chen, J.L., PatrĆcio, P.: Further results on the inverse along an element in semigroups and rings. Linear Multilinear Algebra 64(3), 393ā403 (2016)Zhu, H.H., Chen, J.L., PatrĆcio, P.: Reverse order law for the inverse along an element. Linear Multilinear Algebra 65, 166ā177 (2017)Zhu, H.H., Chen, J.L., PatrĆcio, P., Mary, X.: Centralizerās applications to the inverse along an element. Appl. Math. Comput. 315, 27ā33 (2017)Zhu, H.H., Zhang, X.X., Chen, J.L.: Centralizers and their applications to generalized inverses. Linear Algebra Appl. 458, 291ā300 (2014
Shot noise in mesoscopic systems
This is a review of shot noise, the time-dependent fluctuations in the
electrical current due to the discreteness of the electron charge, in small
conductors. The shot-noise power can be smaller than that of a Poisson process
as a result of correlations in the electron transmission imposed by the Pauli
principle. This suppression takes on simple universal values in a symmetric
double-barrier junction (suppression factor 1/2), a disordered metal (factor
1/3), and a chaotic cavity (factor 1/4). Loss of phase coherence has no effect
on this shot-noise suppression, while thermalization of the electrons due to
electron-electron scattering increases the shot noise slightly. Sub-Poissonian
shot noise has been observed experimentally. So far unobserved phenomena
involve the interplay of shot noise with the Aharonov-Bohm effect, Andreev
reflection, and the fractional quantum Hall effect.Comment: 37 pages, Latex, 10 figures (eps). To be published in "Mesoscopic
Electron Transport," edited by L. P. Kouwenhoven, G. Schoen, and L. L. Sohn,
NATO ASI Series E (Kluwer Academic Publishing, Dordrecht
Responses of marine benthic microalgae to elevated CO<inf>2</inf>
Increasing anthropogenic CO2 emissions to the atmosphere are causing a rise in pCO2 concentrations in the ocean surface and lowering pH. To predict the effects of these changes, we need to improve our understanding of the responses of marine primary producers since these drive biogeochemical cycles and profoundly affect the structure and function of benthic habitats. The effects of increasing CO2 levels on the colonisation of artificial substrata by microalgal assemblages (periphyton) were examined across a CO2 gradient off the volcanic island of Vulcano (NE Sicily). We show that periphyton communities altered significantly as CO2 concentrations increased. CO2 enrichment caused significant increases in chlorophyll a concentrations and in diatom abundance although we did not detect any changes in cyanobacteria. SEM analysis revealed major shifts in diatom assemblage composition as CO2 levels increased. The responses of benthic microalgae to rising anthropogenic CO2 emissions are likely to have significant ecological ramifications for coastal systems. Ā© 2011 Springer-Verlag
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