| 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. |
- Buvall, Lisa, 1976, et al.
(författare)
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Phenotype of early cardiomyopathic changes induced by active immunization of rats with a synthetic peptide corresponding to the second extracellular loop of the human beta-adrenergic receptor
- 2006
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Ingår i: Clin Exp Immunol. - : Oxford University Press (OUP). - 0009-9104. ; 143:2, s. 209-15
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Tidskriftsartikel (refereegranskat)abstract
- In the failing human heart, due to idiopathic dilated cardiomyopathy, it has been suggested that the beta1-adrenergic receptor (beta1AR) is a potential pathogenic autoantigen. The aim of the present study was to investigate whether immunization of rats with a synthetic peptide corresponding to the second extracellular loop of the beta1AR (beta1AR EC(II)) was able to induce the early stage of cardiomyopathy and also to investigate immunological and receptor functional parameters at a transcriptional level to permit insights into the autoimmune mechanism in cardiomyopathy. Eleven Whistar Fur rats were immunized with a beta1AR EC(II) peptide (H26R) once a month during 12 months and seven control rats were injected with vehicle according to the same procedure used for the immunized group. Cardiac function, beta1AR autoantibodies and their functional effects on cardiomyocytes were analysed. beta1AR receptor signalling, immunological and cardiomyocyte stretch markers were determined on transcriptional level. In H26R immunized rats, beta1AR autoantibodies were shown to be present and functionally active, cardiac functions in terms of fractional shortening were decreased and beta1-adrenergic receptor kinase (GRK2) mRNA were increased compared with the control group. These data have shown that immunization of rats with a putative antigenic peptide was able to induce an early stage phenotype of cardiomyopathy in the form of cardiac dysfunction and up-regulation of GRK2 as the first step in the desensitization process of the beta1AR, implying the pathological importance of the beta1AR autoantibody.
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| 3. |
- Chen, D., et al.
(författare)
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Dual-wavelength single-longitudinal-mode erbium-doped fibre laser based on fibre Bragg grating pair and its application in microwave signal generation
- 2008
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 44:7, s. 459-460
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Tidskriftsartikel (refereegranskat)abstract
- A simple dual-wavelength single-longitudinal-mode erbium-doped fibre laser is proposed by incorporating a fibre Bragg grating pair, which is used as a Fabry-Perot filter with two ultra-narrow (similar to 0.12 pm) transmission bands. Stable dual-wavelength single-longitudinal-mode lasing with a wavelength spacing of similar to 0.08 nm is achieved at room temperature. By beating the dual-wavelengths at a photodetector, a microwave signal at 9.616 GHz is demonstrated with a frequency stability better than 1 MHz and a spectral width less that 10 kHz.
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| 4. |
- Chen, Daru R., et al.
(författare)
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Wavelength-spacing continuously tunable multi-wavelength SOA-fiber ring laser based on Mach-Zehnder interferometer
- 2008
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Ingår i: Optics and Laser Technology. - : Elsevier BV. - 0030-3992. ; 40:2, s. 278-281
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Tidskriftsartikel (refereegranskat)abstract
- A Mach-Zehnder interferometer (MZI) which is used as a wavelength-spacing tunable comb filter in a fiber ring laser is built by employing an optical variable delay line (OVDL). Stable multi-wavelength semiconductor optical amplifier (SOA)-fiber ring laser based on an SOA and the MZI comb filter is achieved. Wavelength spacing can be continuously tuned by adjusting the OVDL and, as an example, multi-wavelength lasing with the wavelength spacing of 0.4, 0.8, or 1.6 nm is demonstrated. The output of the proposed multi-wavelength SOA-fiber ring laser is quite stable at room temperature and the output spectrum can be adjusted by controlling the bias current of the SOA.
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| 5. |
- Chen, Daru, et al.
(författare)
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Single-longitudinal-mode erbium-doped fiber laser based on a fiber Bragg grating Fabry-Perot filter
- 2007
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Ingår i: Laser physics. - 1054-660X .- 1555-6611. ; 17:10, s. 1246-1248
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Tidskriftsartikel (refereegranskat)abstract
- A novel single-longitudinal-mode (SLM) erbium-doped fiber laser with a simple linear cavity based on a fiber Bragg grating Fabry-Perot filter (FBG-FPF) and a narrowband (similar to 0.06 nm) FBG is proposed and demonstrated experimentally. Two uniform FBGs form the FBG-FPF, which has two ultranarrow transmission bands with a bandwidth of 0.12 pm and a wavelength spacing of 0.095 nm. By slightly tuning the central wavelength of the narrowband FBG, SLM lasing at 1549.658 or 1549.563 nm (corresponding to the two transmission peaks of the FBG-FPF) is achieved with a laser output power of similar to 4 mW, when the pump power is similar to 75 mW.
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| 6. |
- Chen, Fu
(författare)
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Epstein-Barr virus (EBV) latent membrane protein (LMP) 2A
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Epstein-Barr virus (EBV) is a ubiquitous human herpes virus which infects more than 90% of individuals in the population and is causally implicated in lymphoid and epithelial malignancies. Virus invades oropharyngeal mucosa and establishes latency in memory B lymphocytes. Of eleven genes expression in latency, EBV latent membrane protein 2A (LMP2A) is important for maintenance of latency in infected B lymphocytes. This study aims to investigate the biological role of LMP2A in the EBV latent infection of B cells and in epithelial cells, with a special reference to tumorigenesis. LMP 2A is expressed both in peripheral B lymphocytes of normal EBV latently infected individuals, and EBV-associated diseases, such as NPC, HL and mononucleosis. Our studies revealed that LMP2A transcripts along with EBNA1 (U-K splicing) expressed in small, resting high density B lymphocytes of healthy EBV carriers, was detected. These data indicate that LMP2A seems to play a physiologic role in maintenance of viral latency (Paper I). LMP2A transcripts were detected in 17 of 24 (70%) NPC tumour biopsies, together with EBNA1 that was detected in all samples driven by Qp, LMP1 and LMP2B are 90% of NPC (paper II). These results suggest that LMP2A is implicated not only in viral latent biology, but also in oncogenic pathology. We investigated the role of LMP2A in three aspects: LMP2A recruits WW domain-containing ubiquitin -protein ligases (III), effect of LMP2A on hTE RT/telome rase activity (IV) and on oncogenic pathology (V). We show that the PPPPY motifs of LMP2A bind multiple WW domains of E3 protein-ubiquitin ligases of the Nedd4 family, including A1P4 and KIAA0439, and form physiological complexes with LMP2A in EBV-positive B cells. Consequently, LMP2A enhances Lyn and Syk ubiquitination in vivo and correlates with destabilization of the Lyn tyrosine kinase, however, we have not observed any effect of LMP2A on Syk stability. Thus, LMP2A may potentiate a normal mechanism by which Nedd4 family E3 enzymes regulate B-cell signalling. In addition, LMP2A itself is also ubiquitinated and degraded through proteasome. Therefore, it is likely that LMP2A utilizes ubiquitin-mediated degradation through the proteasome complex to regulate the strength of its own signal, and to further modulate processes of differentiation, activation or survival of B cells in vivo. Recently, several lines of evidence have suggested that activation of telomerase may be a critical for cell immortalization and transformation, in contrast, it is silent in general due to a stringent repression of hTERT in most human somatic cells. Therefore, our interest has been focused on the potential effect of LMP2A on the expression of hTERT/telomerase activity. We found, although unexpected and paradoxical, that LMP2A expression led to the transcriptional repression of the hTERT gene accompanied by a decreased telomerase activity in epithelial cells. Furthermore, LMP2A, through ITAM motif, was shown to inhibit the hTERT promoter activity in both B cells and epithelial cells. Thus, one possibility is that the LMP2A effect on hTERT is related to its role in suppressing physiologic B-cell activation. (Paper IV). Syk tyrosine kinase plays an instrumental role in the EBV infection of B-lymphocytes. However, In line with several recent reports, we have found that the Syk was expressed in human epithelial cell lines, 5637 (derived from human bladder carcinoma) and TW03 (derived from NPC). LMP2A transfectants in 5637 cells could enhance cell growth and produce tumours in SCID mice. LMP2A, via ITAM motifs, bound to and phosphorylated Syk. This correlated with the capacity of LMP2A to induce cell invasion. LMP2A expression or downregulation of Syk by shRNA Syk resulted in enhance of invasive capacity in both cell types, as a potential tumour suppressor. We show that Syk could directly interact with the ITAM-like motif in integrin a6b4, suggesting a6b4 may be the link between Syk and LMP2A-induced invasive capacity. (paper V). These data suggest that LMP2A may use ubiquitination to regulates its own signal strength and further to influence epithelial cell behaviour such as cell adhesion and motility.
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| 7. |
- Chen, Jie, et al.
(författare)
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Effects of autoantibodies removed by immunoadsorption from patients with dilated cardiomyopathy on neonatal rat cardiomyocytes
- 2006
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Ingår i: The European Journal of Heart Failure. - : Wiley. - 1388-9842. ; 8:5, s. 460-467
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Immunoadsorption has been shown to improve cardiac performance and reduce mortality in patients with dilated cardiomyopathy. In this study, the underlying mechanism for these beneficial effects was investigated in cultured rat cardiomyocytes. METHODS AND RESULTS: Immunoadsorption was performed in patients with dilated cardiomyopathy (n=7). Antibody-induced complement-dependent cytotoxicity was investigated by colorimetric MTT. Autoantibodies against the beta(1)-adrenoceptor were detected by ELISA and purified. Column eluent from six patients exhibited a cytotoxic effect, three patients were positive for the beta(1)-adrenoceptor autoantibodies. The purified autoantibodies were able to visualize the beta(1)-adrenoceptors by immunocytofluorescence on rat cardiomyocytes, and also displayed partial agonist properties and induced a positive chronotropic effect, which were blocked by the beta(1)-selective antagonist bisoprolol and the peptide corresponding to the beta(1)-adrenoceptor. Column eluent from one patient induced apoptosis in nick end labelling test (8.1+/-1.7% vs. 2.9+/-1.2% in control, p<0.05). CONCLUSION: Autoantibodies removed by immunoadsorption from patients with dilated cardiomyopathy have a pathophysiological role, as shown by the complement-dependent cytotoxicity and chronotropic action on rat cardiomyocytes. This implies that removal of circulating autoantibodies might be part of the underlying mechanism for improved cardiac function.
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