172 research outputs found

    Inhibition of REV-ERBs stimulates microglial amyloid-beta clearance and reduces amyloid plaque deposition in the 5XFAD mouse model of Alzheimer\u27s disease

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    A promising new therapeutic target for the treatment of Alzheimer\u27s disease (AD) is the circadian system. Although patients with AD are known to have abnormal circadian rhythms and suffer sleep disturbances, the role of the molecular clock in regulating amyloid-beta (Aβ) pathology is still poorly understood. Here, we explored how the circadian repressors REV-ERBα and β affected Aβ clearance in mouse microglia. We discovered that, at Circadian time 4 (CT4), microglia expressed higher levels of the master clock protein BMAL1 and more rapidly phagocytosed fibrillary A

    Uniqueness of roots up to conjugacy for some affine and finite type Artin groups

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    Let GG be one of the Artin groups of finite type Bn=Cn{\mathbf B}_n={\mathbf C}_n, and affine type A~n1\tilde{\mathbf A}_{n-1} and C~n1\tilde{\mathbf C}_{n-1}. In this paper, we show that if α\alpha and β\beta are elements of GG such that αk=βk\alpha^k=\beta^k for some nonzero integer kk, then α\alpha and β\beta are conjugate in GG. For the Artin group of type An\mathbf A_n, this was recently proved by J. Gonz\'alez-Meneses. In fact, we prove a stronger theorem, from which the above result follows easily by using descriptions of those Artin groups as subgroups of the braid group on n+1n+1 strands. Let PP be a subset of {1,...,n}\{1,...,n\}. An nn-braid is said to be \emph{PP-pure} if its induced permutation fixes each iPi\in P, and \emph{PP-straight} if it is PP-pure and it becomes trivial when we delete all the ii-th strands for i∉Pi\not\in P. Exploiting the Nielsen-Thurston classification of braids, we show that if α\alpha and β\beta are PP-pure nn-braids such that αk=βk\alpha^k=\beta^k for some nonzero integer kk, then there exists a PP-straight nn-braid γ\gamma with β=γαγ1\beta=\gamma\alpha\gamma^{-1}. Moreover, if 1P1\in P, the conjugating element γ\gamma can be chosen to have the first strand algebraically unlinked with the other strands. Especially in case of P={1,...,n}P=\{1,...,n\}, our result implies the uniqueness of root of pure braids, which was known by V. G. Bardakov and by D. Kim and D. Rolfsen.Comment: 15 pages, 8 figures; version published by Math.

    Suppression of stored-beam oscillation and observation of flux improvement during top-up injection

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    This paper describes a start-to-end study of the suppression of stored-beam oscillation during top-up injection at the Pohang Light Source (PLS-II) beam line. The fast counterkicker implemented in PLS-II suppresses stored-beam oscillations in the vertical plane. During top-up injection in the magnetic spectroscopy beam line of PLS-II, flux improvement due to the suppression of stored-beam oscillation was clearly observed.11Ysciescopu

    The Intrinsic Shapes of Low-Surface-Brightness Dwarf Irregular Galaxies and Comparison to Other Types of Dwarf Galaxies

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    In this paper, we measure the ellipticities of 30 LSB dI galaxies and compare the ellipticity distribution with that of 80 dEs (Ryden & Terndrup 1994; Ryden et al. 1998) and 62 BCDs (Sung et al. 1998). We find that the ellipticity distribution of LSB dIs is very similar to that of BCDs, and marginally different from that of dEs. We then determine the distribution of intrinsic shapes of dI galaxies and compare to those of other type dwarf galaxies under various assumptions. First, we assume that LSB dIs are either all oblate or all prolate, and use non-parametric analysis to find the best-fitting distribution of intrinsic shapes. With this assumption, we find that the scarcity of nearly circular LSB dIs implies, at the 99% confidence level, that they cannot be a population of randomly oriented oblate or prolate objects. Next, we assume that dIs are triaxial, and use parametric analysis to find permissible distributions of intrinsic shapes. We find that if the intrinsic axis ratios, β\beta and γ\gamma, are distributed according to a Gaussian with means β0\beta_0 and γ0\gamma_0 and a common standard deviation of σ\sigma, the best-fitting set of parameters for LSB dIs is (β0,γ0,σ)=(0.66,0.50,0.15)(\beta_0,\gamma_0,\sigma) = (0.66,0.50,0.15), and the best fit for BCDs is (β0,γ0,σ)=(0.66,0.55,0.16)(\beta_0,\gamma_0,\sigma) = (0.66,0.55,0.16), while the best fit for dEs is (β0,γ0,σ)=(0.78,0.69,0.24)(\beta_0,\gamma_0,\sigma) = (0.78,0.69,0.24). The dIs and BCDs thus have a very similar shape distribution, given this triaxial hypothesis, while the dEs peak at a somewhat more spherical shape. Our results are consistent with an evolutionary scenario in which the three types of dwarf galaxy have a close relation with each other.Comment: total 18 pages, 4 figures, and 3 Tables, submitted to Astrophysical Journal on Mar 5 199

    Evidence for the decay B0->eta pi^0

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    We report a search for the charmless hadronic decay B0ηπ0B^0\to\eta \pi^0 with a data sample corresponding to an integrated luminosity of 694 fb1\rm fb^{-1} containing 753×106753\times10^6 BBˉB\bar{B} pairs. The data were collected by the Belle experiment running on the Υ(4S)\Upsilon(4S) resonance at the KEKB e+ee^+e^- collider. We measure a branching fraction B(B0ηπ0)=(4.11.50.7+1.7+0.5)×107\mathcal{B}(B^0\to\eta\pi^0)=(4.1^{+1.7+0.5}_{-1.5-0.7})\times 10^{-7}, where the first uncertainty is statistical and the second is systematic. Our measurement gives an upper limit of B(B0ηπ0)<6.5×107\mathcal{B}(B^0\to\eta\pi^0)<6.5\times 10^{-7} at 90\% confidence level. The signal has a significance of 3.03.0 standard deviations and constitutes the first evidence for this decay mode.Comment: 11 pages, 3 figures, 2 tables, submitted to Physical Review D(R

    Fabrication of Coaxial Si1−xGex Heterostructure Nanowires by O2 Flow-Induced Bifurcate Reactions

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    We report on bifurcate reactions on the surface of well-aligned Si1−xGex nanowires that enable fabrication of two different coaxial heterostructure nanowires. The Si1−xGex nanowires were grown in a chemical vapor transport process using SiCl4 gas and Ge powder as a source. After the growth of nanowires, SiCl4 flow was terminated while O2 gas flow was introduced under vacuum. On the surface of nanowires was deposited Ge by the vapor from the Ge powder or oxidized into SiO2 by the O2 gas. The transition from deposition to oxidation occurred abruptly at 2 torr of O2 pressure without any intermediate region and enables selectively fabricated Ge/Si1−xGex or SiO2/Si1−xGex coaxial heterostructure nanowires. The rate of deposition and oxidation was dominated by interfacial reaction and diffusion of oxygen through the oxide layer, respectively

    Efficacy of an Educational Material on Second Primary Cancer Screening Practice for Cancer Survivors: A Randomized Controlled Trial

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    <div><h3>Background</h3><p>Cancer surivors have limited knowledge about second primary cancer (SPC) screening and suboptimal rates of completion of screening practices for SPC. Our objective was to test the efficacy of an educational material on the knowledge, attitudes, and screening practices for SPC among cancer survivors.</p> <h3>Methods</h3><p>Randomized, controlled trial among 326 cancer survivors from 6 oncology care outpatient clinics in Korea. Patients were randomized to an intervention or an attention control group. The intervention was a photo-novel, culturally tailored to increase knowledge about SPC screening. Knowledge and attitudes regarding SPC screening were assessed two weeks after the intervention, and screening practices were assessed after one year.</p> <h3>Results</h3><p>At two weeks post-intervention, the average knowledge score was significantly higher in the intervention compared to the control group (0.81 vs. 0.75, P<0.01), with no significant difference in their attitude scores (2.64 vs. 2.57, P = 0.18). After 1 year of follow-up, the completion rate of all appropriate cancer screening was 47.2% in both intervention and control groups.</p> <h3>Conclusion</h3><p>While the educatinal material was effective for increasing knowledge of SPC screening, it did not promote cancer screening practice among cancer survivors. More effective interventions are needed to increase SPC screening rates in this population.</p> <h3>Trial Registration</h3><p>ClinicalTrial.gov <a href="http://clinicaltrials.gov/ct2/show/NCT00948337">NCT00948337</a></p> </div

    Validation of a Mass Spectrometry Method To Quantify Oak Ellagitannins in Wine Samples

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    [EN] Detection and individual quantification of oak wood ellagitannins in oak barrel aged red wine samples are difficult mainly due to their low levels and the similarity between their structures. In this work, a quantification method using mass spectrometry has been developed and validated to quantify wine ellagitannins after sample fractionation with a previously reported method. The use of an internal standard is a requirement to correct mass signal variability. (−)-Gallocatechin, among the different tested compounds, was the only one that proved to be a suitable internal standard making possible the accurate and individual quantification of the main oak wood ellagitannins. The developed methodology has been used to detect and quantify these ellagitannins in different Spanish commercial wines, proving its usefulness

    Relationship between the Sensory-Determined Astringency and the Flavanolic Composition of Red Wines

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    [EN] The relationship between the proanthocyanidin profile and the perceived astringency was assessed in 13 commercial Tempranillo red wines. The concentration and compositional information were obtained by liquid chromatography with diode array detection coupled to electrospray ionization mass spectrometry after acid-catalyzed depolymerization of wine proanthocyanidins in the presence of excess phloroglucinol. Statistical analysis of the results showed significant correlations between sensory and chemical determinations. Astringency was more affected by the subunit composition than by the total concentration or the average degree of polymerization of wine proanthocyanidins. Higher proportions of epicatechin (EC) subunits in extension positions and gallocatechin (GC) subunits in terminal positions were shown to increase astringency. On the contrary, the amount of epigallocatechin (EGC) in both extension and terminal positions was negatively correlated with the perceived astringency
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