556 research outputs found

    Synergistic effects of longitudinal amyloid and vascular changes on lobar microbleeds

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    OBJECTIVE: To determine whether amyloid and hypertensive cerebral small vessel disease (hCSVD) changes synergistically affect the progression of lobar microbleeds in patients with subcortical vascular mild cognitive impairment (svMCI). METHODS: Among 72 patients with svMCI who underwent brain MRI and [11C] Pittsburgh compound B (PiB)–PET, 52 (72.2%) completed the third year of follow-up. These patients were evaluated by annual neuropsychological testing, brain MRI, and follow-up PiB-PET. RESULTS: Over 3 years, 31 of 52 patients (59.6%) had incident cerebral microbleeds (CMBs) in the lobar and deep regions. Both baseline and longitudinal changes in lacune numbers were associated with increased numbers of lobar and deep microbleeds, while baseline and longitudinal changes in PiB uptake ratio were associated only with the progression of lobar microbleeds, especially in the temporal, parietal, and occipital areas. Regional white matter hyperintensity severity was also associated with regional lobar CMBs in the parietal and occipital regions. There were interactive effects between baseline and longitudinal lacune number and PiB retention on lobar microbleed progression. Increased lobar, but not deep, CMBs were associated with decreased scores in the digit span backward task and Rey-Osterrieth Complex Figure Test. CONCLUSIONS: Our findings suggest that amyloid-related pathology and hCSVD have synergistic effects on the progression of lobar microbleeds, providing new clinical insight into the interaction between amyloid burden and hCSVD on CMB progression and cognitive decline with implications for developing effective prevention strategies

    CAR T cells targeting BAFF-R can overcome CD19 antigen loss in B cell malignancies

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    CAR T cells targeting CD19 provide promising options for treatment of B cell malignancies. However, tumor relapse from antigen loss can limit efficacy. We developed humanized, second-generation CAR T cells against another B cell–specific marker, B cell activating factor receptor (BAFF-R), which demonstrated cytotoxicity against human lymphoma and acute lymphoblastic leukemia (ALL) lines. Adoptively transferred BAFF-R-CAR T cells eradicated 10-day preestablished tumor xenografts after a single treatment and retained efficacy against xenografts deficient in CD19 expression, including CD19-negative variants within a background of CD19-positive lymphoma cells. Four relapsed, primary ALLs with CD19 antigen loss obtained after CD19-directed therapy retained BAFF-R expression and activated BAFF-R-CAR, but not CD19-CAR, T cells. BAFF-R-CAR, but not CD19-CAR, T cells also demonstrated antitumor effects against an additional CD19 antigen loss primary patient–derived xenograft (PDX) in vivo. BAFF-R is amenable to CAR T cell therapy, and its targeting may prevent emergence of CD19 antigen loss variants

    A Study of D0 --> K0(S) K0(S) X Decay Channels

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    Using data from the FOCUS experiment (FNAL-E831), we report on the decay of D0D^0 mesons into final states containing more than one KS0K^0_S. We present evidence for two Cabibbo favored decay modes, D0→KS0KS0K−π+D^0\to K^0_SK^0_S K^- \pi^+ and D0→KS0KS0K+π−D^0\to K^0_SK^0_S K^+ \pi^-, and measure their combined branching fraction relative to D0→Kˉ0π+π−D^0\to \bar{K} ^0\pi^+\pi^- to be Γ(D0→KS0KS0K±π∓)Γ(D0→Kˉ0π+π−)\frac{\Gamma(D^0\to K^0_SK^0_SK^{\pm}\pi^{\mp})}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0106 ±\pm 0.0019 ±\pm 0.0010. Further, we report new measurements of Γ(D0→KS0KS0KS0)Γ(D0→Kˉ0π+π−)\frac{\Gamma(D^0\to K^0_SK^0_SK^0_S)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0179 ±\pm 0.0027 ±\pm 0.0026, Γ(D0→K0Kˉ0)Γ(D0→Kˉ0π+π−)\frac{\Gamma(D^0\to K^0\bar{K} ^0)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0144 ±\pm 0.0032 ±\pm 0.0016, and Γ(D0→KS0KS0π+π−)Γ(D0→Kˉ0π+π−)\frac{\Gamma(D^0\to K^0_SK^0_S\pi^+\pi^-)}{\Gamma(D^0\to \bar{K} ^0\pi^+\pi^-)} = 0.0208 ±\pm 0.0035 ±\pm 0.0021 where the first error is statistical and the second is systematic.Comment: 11 pages, 3 figures, typos correcte

    Measurement of the Relative Branching Fraction of Υ(4S)\Upsilon(4S) to Charged and Neutral B-Meson Pairs

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    We analyze 9.7 x 10^6 B\bar{B}$ pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Y(4S) resonance. We measure the rates for B^0 -> J/psi K^{(*)0} and B^+ -> J/psi K^{(*)+} decays and use the world-average B-meson lifetime ratio to extract the relative widths f+-/f00 = Gamma(Y(4S) -> B+B-)/Gamma(Y(4S) -> B0\bar{B0}) = = 1.04 +/- 0.07(stat) +/- 0.04(syst). With the assumption that f+- + f00 = 1, we obtain f00 = 0.49 +/- 0.02(stat) +/- 0.01(syst) and f+- = 0.51 +/- 0.02(stat) +/- 0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Y(4S) resonance.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    First Observation of the Decays B0→D∗−ppˉπ+B^{0}\to D^{*-}p\bar{p}\pi^{+} and B^{0}\to D^{*-}p\bar{n}$

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    We report the first observation of exclusive decays of the type B to D^* N anti-N X, where N is a nucleon. Using a sample of 9.7 times 10^{6} B-Bbar pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B^0 \to D^{*-} proton antiproton \pi^+) = ({6.5}^{+1.3}_{-1.2} +- 1.0) \times 10^{-4} and B(B^0 \to D^{*-} proton antineutron) = ({14.5}^{+3.4}_{-3.0} +- 2.7) times 10^{-4}. Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Study of the Decays B0 --> D(*)+D(*)-

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    The decays B0 --> D*+D*-, B0 --> D*+D- and B0 --> D+D- are studied in 9.7 million Y(4S) --> BBbar decays accumulated with the CLEO detector. We determine Br(B0 --> D*+D*-) = (9.9+4.2-3.3+-1.2)e-4 and limit Br(B0 --> D*+D-) < 6.3e-4 and Br(B0 --> D+D-) < 9.4e-4 at 90% confidence level (CL). We also perform the first angular analysis of the B0 --> D*+D*- decay and determine that the CP-even fraction of the final state is greater than 0.11 at 90% CL. Future measurements of the time dependence of these decays may be useful for the investigation of CP violation in neutral B meson decays.Comment: 21 pages, 5 figures, submitted to Phys. Rev.

    A Search for B→τνB\to \tau\nu

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    We report results of a search for B→τνB\to\tau\nu in a sample of 9.7 million charged BB meson decays. The search uses both πν\pi\nu and ℓννˉ\ell\nu\bar\nu decay modes of the τ\tau, and demands exclusive reconstruction of the companion Bˉ\bar B decay to suppress background. We set an upper limit on the branching fraction B(B→τν)<8.4×10−4{\cal B}(B\to \tau\nu) < 8.4\times 10^{-4} at 90% confidence level. With slight modification to the analysis we also establish B(B±→K±ννˉ)<2.4×10−4{\cal B}(B^\pm\to K^\pm\nu\bar\nu) < 2.4\times 10^{-4} at 90% confidence level.Comment: 10 ages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Measurements of B --> D_s^{(*)+} D^{*(*)} Branching Fractions

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    This article describes improved measurements by CLEO of the B0→Ds+D∗−B^0 \to D_s^+ D^{*-} and B0→Ds∗+D∗−B^0 \to D_s^{*+} D^{*-} branching fractions, and first evidence for the decay B+→Ds(∗)+Dˉ∗∗0B^+ \to D_s^{(*)+} \bar{D}^{**0}, where Dˉ∗∗0\bar{D}^{**0} represents the sum of the Dˉ1(2420)0\bar{D}_1(2420)^0, Dˉ2∗(2460)0\bar{D}_2^*(2460)^0, and Dˉ1(j=1/2)0\bar{D}_1(j=1/2)^0 L=1 charm meson states. Also reported is the first measurement of the Ds∗+D_s^{*+} polarization in the decay B0→Ds∗+D∗−B^0 \to D_s^{*+} D^{*-}. A partial reconstruction technique, employing only the fully reconstructed Ds+D_s^+ and slow pion πs−\pi_s^- from the D∗−→Dˉ0πs−D^{*-} \to \bar{D}^0 \pi^-_s decay, enhances sensitivity. The observed branching fractions are B(B0→Ds+D∗−)=(1.10±0.18±0.10±0.28){\mathcal B} (B^0 \to D_s^+ D^{*-}) = (1.10 \pm 0.18 \pm 0.10 \pm 0.28)%, B(B0→Ds∗+D∗−)=(1.82±0.37±0.24±0.46){\mathcal B} (B^0 \to D_s^{*+} D^{*-}) = (1.82 \pm 0.37 \pm 0.24 \pm 0.46)%, and B(B+→Ds(∗)+Dˉ∗∗0)=(2.73±0.78±0.48±0.68){\mathcal B} (B^+ \to D_s^{(*)+} \bar{D}^{**0}) = (2.73 \pm 0.78 \pm 0.48 \pm 0.68)%, where the first error is statistical, the second systematic, and the third is due to the uncertainty in the Ds+→ϕπ+D_s^+ \to \phi \pi^+ branching fraction. The measured Ds∗+D_s^{*+} longitudinal polarization, ΓL/Γ=(50.6±13.9±3.6)\Gamma_L/\Gamma = (50.6 \pm 13.9 \pm 3.6)%, is consistent with the factorization prediction of 54%.Comment: 26 pages (LaTeX), 15 figures. To be submitted to PR

    Improved Measurement of the Pseudoscalar Decay Constant fDsf_{D_{s}}

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    We present a new determination of the Ds decay constant, f_{Ds} using 5 million continuum charm events obtained with the CLEO II detector. Our value is derived from our new measured ratio of widths for Ds -> mu nu/Ds -> phi pi of 0.173+/- 0.021 +/- 0.031. Taking the branching ratio for Ds -> phi pi as (3.6 +/- 0.9)% from the PDG, we extract f_{Ds} = (280 +/- 17 +/- 25 +/- 34){MeV}. We compare this result with various model calculations.Comment: 23 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN

    Precise Measurement of B^{0}\to \bar{B^{0} Mixing Parameters at the Υ(\Upsilon(S)$

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    We describe a measurement of B^0-B^0bar mixing parameters exploiting a method of partial reconstruction of the decay chains B0 -> D^{*-}\pi^+ and B0 -> D^{*-}\rho^+. Using 9.6 x 10^6 BBbar pairs collected at the Cornell Electron Storage Ring, we find \chi_d = 0.198 +- 0.013 +- 0.014, |y_d|<0.41 at 95% confidence level, and |Re(\epsilon_B)|<0.034 at 95% confidence level.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN
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