537 research outputs found

    Retinal S-antigen Th1 cell epitope mapping in patients with Behcet's disease

    Get PDF
    Background - Retinal S-antigen (S-Ag) is a most characterized autoantigen of autoimmune uveitis. The recognized immunodominant epitope of human S-Ag in patients with uveitis has not been identified. In this study, we selected certain patients with active uveitis to map the Th1 cell epitope spectrum of human S-Ag in Behcet's disease(BD). Methods - Blood samples were taken from eight active BD patients who showed an immune response to 40 mixed overlapping peptides spanning the entire sequence of human S-Ag. Peripheral blood mononuclear cells were isolated and stimulated with single S-Ag peptide at 5 mu g/ml or 20 mu g/ml. Single-cell immune responses were measured by IFN-gamma ELIspot assay. Results - BD patients heterogeneously responded to the S-Ag peptides at two concentrations. In general, the responses to 5 mu g/ml peptides were slightly stronger than those to 20 mu g/ml peptides, while the maximum SFC frequency to single peptide at the two concentrations was similar. Several peptides including P31, P35 and P40 induced a prominent response, with the frequency of S-Ag specific cells being about 0.007%. Significant reactivity pattern shift was noted in patients with different disease courses. Conclusions - Certain active BD patients have S-Ag specific Th1 cells with a low frequency. The S-Ag epitope specificity between patients is highly heterogeneous, and varies with the uveitis cours

    Splenic CD8(+) T cells secrete TGF-beta 1 to exert suppression in mice with anterior chamber-associated immune deviation

    Get PDF
    Background CD8(+) regulatory T cells (Treg) have been considered to be involved in a model of ocular-induced tolerance, known as anterior chamber-associated immune deviation (ACAID). The mechanisms of suppression by CD8(+) T cells in ACAID remain only poorly understood. TGF-beta 1 is considered as an inhibitory cytokine for immunosuppression in some models. The production of TGF-beta 1 by CD8(+) T cells in ACAID, and whether CD8+ T cells exert suppression through TGF-beta 1, is unknown. Methods The suppressive effect of CD8(+) T cells in ACAID mice was determined by a local adoptive transfer (LAT) assay. The production of TGF-beta 1 by CD8(+) T cells was measured by enzyme-linked immunosorbent assay (ELISA). Anti-TGF-beta 1 antibodies were used in the LAT assay to test if they could block the inhibitory effect of CD8(+) T cells. Results CD8(+) T cells from ACAID mice were shown to block the delayed-type hypersensitivity (DTH) response in an antigen-specific manner in a LAT assay. These CD8+ T cells secreted TGF-beta 1, and their suppression could partially be blocked by anti-TGF-beta 1 antibodies. Conclusions Our study confirms that CD8+ T cells from ACAID mice possess inhibitory properties. This population exerts part of its suppressive function via the production of TGF-beta 1

    Correlation dynamics between electrons and ions in the fragmentation of D2_2 molecules by short laser pulses

    Full text link
    We studied the recollision dynamics between the electrons and D2+_2^+ ions following the tunneling ionization of D2_2 molecules in an intense short pulse laser field. The returning electron collisionally excites the D2+_2^+ ion to excited electronic states from there D2+_2^+ can dissociate or be further ionized by the laser field, resulting in D+^+ + D or D+^+ + D+^+, respectively. We modeled the fragmentation dynamics and calculated the resulting kinetic energy spectrum of D+^+ to compare with recent experiments. Since the recollision time is locked to the tunneling ionization time which occurs only within fraction of an optical cycle, the peaks in the D+^+ kinetic energy spectra provides a measure of the time when the recollision occurs. This collision dynamics forms the basis of the molecular clock where the clock can be read with attosecond precision, as first proposed by Corkum and coworkers. By analyzing each of the elementary processes leading to the fragmentation quantitatively, we identified how the molecular clock is to be read from the measured kinetic energy spectra of D+^+ and what laser parameters be used in order to measure the clock more accurately.Comment: 13 pages with 14 figure

    Partonic flow and ϕ\phi-meson production in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

    Get PDF
    We present first measurements of the ϕ\phi-meson elliptic flow (v2(pT)v_{2}(p_{T})) and high statistics pTp_{T} distributions for different centralities from sNN\sqrt{s_{NN}} = 200 GeV Au+Au collisions at RHIC. In minimum bias collisions the v2v_{2} of the ϕ\phi meson is consistent with the trend observed for mesons. The ratio of the yields of the Ω\Omega to those of the ϕ\phi as a function of transverse momentum is consistent with a model based on the recombination of thermal ss quarks up to pT4p_{T}\sim 4 GeV/cc, but disagrees at higher momenta. The nuclear modification factor (RCPR_{CP}) of ϕ\phi follows the trend observed in the KS0K^{0}_{S} mesons rather than in Λ\Lambda baryons, supporting baryon-meson scaling. Since ϕ\phi-mesons are made via coalescence of seemingly thermalized ss quarks in central Au+Au collisions, the observations imply hot and dense matter with partonic collectivity has been formed at RHIC.Comment: 6 pages, 4 figures, submit to PR

    Measurement of the Bottom contribution to non-photonic electron production in p+pp+p collisions at s\sqrt{s} =200 GeV

    Get PDF
    The contribution of BB meson decays to non-photonic electrons, which are mainly produced by the semi-leptonic decays of heavy flavor mesons, in p+pp+p collisions at s=\sqrt{s} = 200 GeV has been measured using azimuthal correlations between non-photonic electrons and hadrons. The extracted BB decay contribution is approximately 50% at a transverse momentum of pT5p_{T} \geq 5 GeV/cc. These measurements constrain the nuclear modification factor for electrons from BB and DD meson decays. The result indicates that BB meson production in heavy ion collisions is also suppressed at high pTp_{T}.Comment: 6 pages, 4 figures, accepted by PR

    Measurement of Transverse Single-Spin Asymmetries for Di-Jet Production in Proton-Proton Collisions at s=200\sqrt{s} = 200 GeV

    Get PDF
    We report the first measurement of the opening angle distribution between pairs of jets produced in high-energy collisions of transversely polarized protons. The measurement probes (Sivers) correlations between the transverse spin orientation of a proton and the transverse momentum directions of its partons. With both beams polarized, the wide pseudorapidity (1η+2-1 \leq \eta \leq +2) coverage for jets permits separation of Sivers functions for the valence and sea regions. The resulting asymmetries are all consistent with zero and considerably smaller than Sivers effects observed in semi-inclusive deep inelastic scattering (SIDIS). We discuss theoretical attempts to reconcile the new results with the sizable transverse spin effects seen in SIDIS and forward hadron production in pp collisions.Comment: 6 pages total, 1 Latex file, 3 PS files with figure

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

    Get PDF
    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

    Association between first caesarean delivery and adverse outcomes in subsequent pregnancy: a retrospective cohort study

    Get PDF
    BACKGROUND:Few studies have explored the association between a previous caesarean section (CS) and adverse perinatal outcomes in a subsequent pregnancy, especially in women who underwent a non-indicated CS in their first delivery. We designed this study to compare the perinatal outcomes of a subsequent pregnancy in women who underwent spontaneous vaginal delivery (SVD) or CS in their first delivery. METHODS:This retrospective cohort study included women who underwent singleton deliveries at the International Peace Maternity and Child Health Hospital from January 2013 to December 2016. Data on the perinatal outcomes of all the women were extracted from the medical records. Multivariate logistic regression was conducted to assessed the association between CS in the first delivery and adverse perinatal outcomes in the subsequent pregnancy. RESULTS:CS delivery in the subsequent pregnancy was more likely for women who underwent CS in their first birth than for women with previous SVD (97.3% versus 13.2%). CS in the first birth was also associated with a significantly increased risk of adverse outcomes in the subsequent pregnancy, especially in women who underwent a non-indicated CS. Adverse perinatal outcomes included pregnancy-induced hypertension [adjusted odds ratio (OR), 95% confidence interval (CI): 2.20, 1.59-3.05], gestational diabetes mellitus (1.82, 1.57-2.11), gestational anaemia (1.27, 1.05-1.55), placenta previa (3.18, 2.15-4.71), placenta accreta (2.75, 1.75-4.31), and polyhydramnios (2.60, 1.57-4.31) in the mother and preterm delivery (1.37, 1.06-1.78), low birth weight (3.78, 2.07-6.90), macrosomia (5.04, 3.95-6.44), and neonatal jaundice (1.72, 1.39-2.14) in the baby. CONCLUSIONS:CS in the first delivery markedly increases the risk of repeated CS and maternal-fetal complications in the subsequent pregnancy, especially in women with a non-indicated CS.Hong-Tao Hu, Jing-Jing Xu, Jing Lin, Cheng Li, Yan-Ting Wu, Jian-Zhong Sheng, Xin-Mei Liu and He-Feng Huan

    PENENTUAN MASSA FOTOKATALIS DAN SUHU OPTIMUM PADA PROSES FOTODEGRADASI ZAT WARNA RHODAMIN B MENGGUNAKAN FOTOKATALIS TiO2(DETERMINATION OF OPTIMUM TEMPERATURE AND PHOTOCATALYST MASS OF RHODAMINE B PHOTODEGRADATION PROCESS BY TiO2 PHOTOCATALYST)

    Get PDF
    Abstrak Telah dilakukan penelitian tentang penentuan massa fotokatalis dan suhu optimum pada proses fotodegradasi zat warna Rhodamin B menggunakan fotokatalis TiO2. Massa fotokatalis dan suhu optimum pada proses fotodegradasi zat warna Rhodamin B ditentukan dengan variasi massa 0 mg sampai 100 mg dan variasi suhu 30 oC sampai 60 oC. Fotodegradasi dilakukan dalam reaktor tertutup yang dilengkapi dengan lampu UV. Konsentrasi zat warna yang tersisa setelah fotodegradasi diukur dengan spektrofotometer UV-Vis. Kondisi maksimum pengukuran adalah pada panjang gelombang 553,40 nm.  Hasil penelitian menunjukkan bahwa massa fotokatalis optimum pada proses fotodegradasi zat warna Rhodamin B sebesar 70 mg dan suhu optimum pada 50 oC. Kata kunci: massa fotokatalis, suhu larutan, Rhodamin B, TiO2. Abstract The determination of optimum temperature and photocatalyst mass of Rhodamine B photodegradation process was studied using TiO2 as catalyst. Optimum temperature and photocatalyst mass of Rhodamine B photodegradation process was determined by variation of mass 0 mg to 100 mg and variation of temperature at 30 oC to 60 oC. Photodegradation carried out in a closed reactor completed with UV lamp. The remaining of Rhodamine B concentration after photodegradation was measured by UV-Vis spectrophotometer. Maximum condition of measurement was at wavelength of 553,40 nm. The result showed that optimum photocatalyst mass of Rhodamine B photodegradation process was 70 mg and optimum temperature was 50 oC. Key Words: photocatalyst mass, solution’s temperature, Rhodamine B, TiO
    corecore