| 1. |
- Ablikim, M., et al.
(författare)
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Measurements of (XcJ)-> K+K-K+K- decays
- 2006
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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| 2. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 3. |
- Deng, R., et al.
(författare)
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Surface morphology, structural and optical properties of polar and non-polar ZnO thin films : A comparative study
- 2009
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Ingår i: Journal of Crystal Growth. - : Elsevier BV. - 0022-0248. ; 311:19, s. 4398-4401
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Tidskriftsartikel (refereegranskat)abstract
- The polar and non-polar ZnO thin films were fabricated on cubic MgO (1 1 1) and (0 0 1) substrates by plasma-assisted molecular beam epitaxy. Based on X-ray diffraction analysis, the ZnO thin films grown on MgO (1 1 1) and (1 0 0) substrates exhibit the polar c-plane and non-polar m-plane orientation, respectively. Comparing with the c-plane ZnO film, the non-polar m-plane ZnO film shows cross-hatched stripes-like morphology, lower surface roughness and slower growth rate. However, low-temperature photoluminescence measurement indicates the m-plane ZnO film has a stronger 3.31 eV emission, which is considered to be related to stacking faults. Meanwhile, stronger band tails absorbance of the m-plane ZnO film is observed in optical absorption spectrum.
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| 4. |
- Yang, Rui, et al.
(författare)
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Antigen and epitope specificity of anti-glomerular basement membrane antibodies in patients with Goodpasture disease with or without anti-neutrophil cytoplasmic antibodies
- 2007
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Ingår i: Journal of the American Society of Nephrology. - 1046-6673. ; 18:4, s. 1338-1343
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Tidskriftsartikel (refereegranskat)abstract
- Goodpasture disease (GP) is defined by the presence of anti-glomerular basement membrane (anti-GBM) antibodies and rapidly progressive glomerulonephritis. Besides anti-GBM, many patients with GP produce anti-neutrophil cytoplasmic antibodies (ANCA). For elucidation of the pathophysiologic significance of ANCA in this setting, epitope and antigen specificity of the anti-GBM antibodies and antigen specificity of ANCA were studied. Bovine testis a(IV)NC1 (tNC1); recombinant human alpha 1, alpha 3, alpha 4, and alpha 5(IV)NC1 (r alpha 1 through r alpha 5); and three chimeric proteins that contain previously defined epitope regions designated E-A, E-B, and S2 were used to examine the anti-GBM antibodies by ELISA in 205 Chinese patients with GP with or without ANCA. In the 205 anti-GBM antibody-positive sera, 63 (30.7%) were also ANCA positive (61 myeloperoxidase-ANCA and six proteinase 3-ANCA, four being triple positive). All 205 sera recognized tNC1 and r alpha 3(IV)NC1. In the double-positive group, 54.0, 66.7, 71.4% of the sera could recognize r alpha 1, r alpha 4, and r alpha 5, respectively, compared with 49.3, 60.6, and 55.6% for patients with anti-GBM antibodies alone. The levels of the antibodies to r alpha 3, tNC1, and the alpha 3/alpha 1 ratio were lower in the double-positive group than that in patients with anti-GBM antibody alone (P < 0.05). Most of the sera could recognize the epitope regions E-A,E-B, and S2, but the absorbance values to EA, EB, and S2 were lower in double-positive group (P < 0.05). Double-positive patients had a broader spectrum of anti-GBM antibodies and lower levels of antibodies against alpha 3(IV)NC1 compared with that of patients with anti-GBM antibodies alone.
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| 5. |
- Yang, Rui, et al.
(författare)
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Levels of epitope-specific autoantibodies correlate with renal damage in anti-GBM disease
- 2009
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Ingår i: Nephrology Dialysis Transplantation. - Oxford, UK : Oxford University Press (OUP). - 1460-2385 .- 0931-0509. ; 24:6, s. 1838-1844
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Tidskriftsartikel (refereegranskat)abstract
- Background. Although the clinical importance of demonstrating the presence of anti-glomerular basement membrane (anti-GBM) antibodies is well established, less is known concerning the clinical utility of measuring the levels of autoantibodies. Two conformational epitopes of anti-GBM antibodies have been defined at residues 17-31 and 127-141 of the alpha 3(IV)NC1 domain of type IV collagen [alpha 3(IV)NC1], which were named as EA and EB, respectively. In order to elucidate the importance of such antibodies, we studied the levels and the epitope specificities of anti-GBM antibodies in a large cohort of Chinese patients with anti-GBM disease. Methods. All patients, with anti-GBM disease and available clinical data, diagnosed at Peking University First Hospital from 1996 to 2005 were included in the present study. Recombinant chimeric proteins containing previously defined epitope regions designated as EA and EB were used to detect anti-GBM antibodies by ELISA. Results were compared and correlated with clinical data collected at the time of diagnosis, biopsy findings and outcome after 1 year of follow-up. Results. A retrospective diagnosis of anti-GBM disease was made in 147 patients. Haemoptysis was recorded for 47% of these cases while 53.5% cases had oliguria or anuria at the time of diagnosis. Among these patients, the levels of anti-GBM antibodies correlated with serum creatinine at diagnosis (P < 0.05 for anti EA, EB and alpha 3(IV)NC1). Oliguric patients had higher levels of autoantibodies than non-oliguric patients, however, the difference being statistically significant only for EB (P < 0.05). Renal biopsies were performed in 66 patients, and it was found that 50 (75.8%) had cresent formation in > 85% of the glomeruli. There was a correlation between the percentage of crescents and levels of antibodies, but it was significant only for anti-EA antibodies (P < 0.05). Clinical data regarding the follow-up were available for 102 patients; at the end of 1 year, 88 (86.3%) were either dead or dialysis dependent. The absorbance values of anti-GBM antibodies against both EA and EB were also associated with the subsequent development, death or terminal renal insufficiency (P < 0.05). Conclusion. In this study, patients with high levels of circulating antibodies against the specific epitopes EA and EB had a more severe renal disease at diagnosis as well as a worse prognosis.
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| 6. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 7. |
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| 8. |
- Willander, Magnus, et al.
(författare)
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Light-emitting diodes based on n-ZnO nano-wires and p-type organic semiconductors
- 2008
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Ingår i: Proc. SPIE 6895. - : SPIE - International Society for Optical Engineering. ; 6895, s. 68950O-1-10-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- After our recent successful demonstration of high brightness white light emitting diodes (HB-LEDs) based on high temperature grown n-ZnO nanowires on different p-type semiconductors, we present here LEDs fabricated on n-ZnO nano-wires and p-type organic semiconductors. By employing a low temperature chemical growth (≤ 90 °C) approach for ZnO synthesis combined together with organic p-type semiconductors, we demonstrate high quality LEDs fabricated on a variety of different substrates. The substrates include transparent glass, plastic, and conventional Si. Different multi-layers of p-type organic semiconductors with or without electron blocking layers have been demonstrated and characterized. The investigated p-type organic semiconductors include PEDOT:PSS, which was used as a anode in combination with other p-type polymers. Some of the heterojunction diodes also contain an electron blocking polymer sandwiched between the p-type polymer and the n-ZnO nano-wire. The insertion of electron blocking layer is necessary to engineer the device for the desired emission. Structural and electrical results will be presented. The preliminary I-V characteristics of the organic-inorganic hybrid heterojunction diodes show good rectifying properties. Finally we also present our findings on the origin of the green luminescence band which is responsible of the white light emission in ZnO is discussed.
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| 9. |
- Willander, Magnus, 1948-, et al.
(författare)
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ZnO nanowires : chemical growth, electro-deposition and application to intracellular nano-sensors
- 2008
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Ingår i: Physica Status Solidi. C, Current topics in solid state physics. - : Wiley. - 1610-1634 .- 1610-1642 .- 1862-6351. ; 5:9, s. 3076-3083
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present our results on growth, characterization, and nano-devices based on ZnO nano-structures. The ZnO nano-structures were grown by mainly two methods, the catalytic Vapor Liquid Solid (VLS) and the low temperature chemical growth. We show that by multiple coating combined with low temperature chemical growth, well aligned with size controlled ZnO nanowires on silicon substrates can be achieved. The dissolution, due to its important on the stability of ZnO nano-structures in aqueous medium, is then discussed and some preliminary experimental results are shown. Basic Optical characteristics of ZnO nano-rods are briefly discussed. Finally, electrochemical intracellular nano-sensors based on ZnO nano-wires are demonstrated as efficient nano-sensors for monitoring the human cell activity with minute pH changes. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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| 10. |
- Yang, J. H., et al.
(författare)
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Photoluminescence property of InAs quantum dots with InxGa1-x as layer inserted
- 2005
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Ingår i: Kao Teng Hsueh Hsiao Hua Heush Hsueh Pao/ Chemical Journal of Chinese Universities. - 0251-0790. ; 26:10, s. 1926-1929
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Tidskriftsartikel (refereegranskat)abstract
- InAs quantum dots (QDs) have been grown on the GaAs(001) substrates by the method of molecular beam epitaxy. The emission of InAs QDs can be turned to about 1300 nm by the introduction of a 10 ML In0.4Ga0.6 As layer. The photoluminescence of the samples were studied before and after being treated by hydrogen plasma. The results show that the enhancement of the PL intensity after H-plasma treatment depends on the excitation power, from about a factor of 12 at the low excitation limit to about a factor of 2 at the highest excitation power used in this study, which are probably due to competition between carrier capture by nonradi-ative centers and InAs QDs. PL intensity variation with the chauge of time and temperature were also investigated, and the results of them clearly illustrate that there indeed exist interface defects, both on the interface between the InAs dots and surrounding layers and in the GaAs layers, which can be suppressed heavily by H-treatments so that the PL intensity can be enhanced greatly.
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