474 research outputs found
Delocalization transition of a disordered axion insulator
The axion insulator is a higher-order topological insulator protected by inversion symmetry. We show that, under quenched disorder respecting inversion symmetry on average, the topology of the axion insulator stays robust, and an intermediate metallic phase in which states are delocalized is unavoidable at the transition from an axion insulator to a trivial insulator. We derive this conclusion from general arguments, from classical percolation theory, and from the numerical study of a 3D quantum network model simulating a disordered axion insulator through a layer construction. We find the localization length critical exponent near the delocalization transition to be ν=1.42±0.12. We further show that this delocalization transition is stable even to weak breaking of the average inversion symmetry, up to a critical strength. We also quantitatively map our quantum network model to an effective Hamiltonian and we find its low-energy k⋅p expansion
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Experimental characterization of ATF beam position monitor
Performance of the stripline beam position monitor (BPM) at Brookhaven Accelerator Test Facility (ATF) was experimentally characterized. The design of the BPM and its local receive were discussed briefly. The dynamic range of the BPM was measured from a few pC to an 0.5 nC charge without saturation. The resolution of the BPM was measured to be 150 {micro}m for a 200 pC charge electron bunch. The BPM sum signal was also used to investigate the timing jitter between the RF gun driving laser system and the ATF linac RF system, the sensitivity for timing jitter measurement was measured to be 6m V/ps
Bezafibrate treatment is associated with a reduced rate of re-hospitalization in smokers after acute coronary syndrome
Background: Significantly increased rate of hospitalizations in current smokers is a major smoking-related problem which is associated with a heavy economic burden, whereas carÂdiovascular disease accounted for nearly half of hospitalizations. The effect of bezafibrate on the rate of re-hospitalization in smokers already treated with statin immediately post-acute coronary syndrome (ACS) is unknown. The aim of this study was to investigate 30-day rate of re-hospitalization in current smokers participating in the ACS Israeli Surveys (ACSIS) and who were treated on discharge with a bezafibrate/statin combination vs. statin alone. Methods: The study population comprised 3392 patients with confirmed current smoking status from the ACSIS 2000, 2002, 2004, 2006, 2008 and 2010 enrollment waves who were alive on discharge and received statin. Of these, 3189 (94%) were discharged with statin alone, 203 (6%) with a combination of a statin and bezafibrate. Results: Thirty-day re-hospitalization rate was significantly lower in patients from the comÂbination group than in their counterparts from the statin monotherapy group: 12.8% vs. 19%, p = 0.028. Multivariable analysis identified the combined bezafibrate/statin treatment as an independent predictor of reduced risk of 30-day re-hospitalization rate with odds ratio (OR) 0.53 (95% confidence interval [CI] 0.31–0.91), and it corresponded to 47% risk reduction. Other significant variables in our model associated with independent risk of 30-day re-hospiÂtalization rate during the follow-up were female gender (OR 1.43, CI 1.05–1.95, p = 0.03) and age > 65 years (OR 1.49, CI 1.13–1.95, p = 0.004). Conclusions: Adding bezafibrate to statin in smokers was associated with a significantly reduced 30-day rate of re-hospitalization after ACS.
Long-term effects of peroxisome proliferator-activated receptor ligand bezafibrate on N-terminal pro-B type natriuretic peptide in patients with advanced functional capacity impairment
<p>Abstract</p> <p>Background</p> <p>The effects of pan-peroxisome proliferator-activated receptor (PPAR) ligand bezafibrate on N-terminal pro-B type natriuretic peptide (ProBNP) level in patients with coronary artery disease (CAD) is unknown. The current study aimed to investigate the long-term effects of bezafibrate on ProBNP level in patients with pre-existing CAD and advanced functional capacity impairment.</p> <p>Methods</p> <p>Metabolic and inflammatory parameters were analyzed from stored frozen serum samples obtained from 108 patients enrolled in the Bezafibrate Infarction Prevention (BIP) Study. They presented with New York Heart Association (NYHA) functional class III, comprising 58 patients in the bezafibrate group and 50 in the placebo groups, and completed a 2-year prospective, double-blind, placebo-controlled follow-up.</p> <p>Results</p> <p>During follow-up ProBNP level did not change significantly in the placebo group, whereas it increased slightly in the bezafibrate group, which was older and with lower baseline ProBNP values. No significant differences between the groups were found for ProBNP levels after 2 year of follow-up. Analysis-of-covariance (ANCOVA) -taking into account age and baseline ProBNP level- showed that bezafibrate was not associated with longitudinal ProBNP changes during the follow-up period (p = 0.3).</p> <p>Conclusion</p> <p>Long-term treatment by bezafibrate was not associated with longitudinal ProBNP changes in patients with pre-existing CAD and advanced functional capacity impairment.</p
Does the lipid-lowering peroxisome proliferator-activated receptors ligand bezafibrate prevent colon cancer in patients with coronary artery disease?
<p>Abstract</p> <p>Background</p> <p>Epidemiologic studies have suggested that hypertriglyceridemia and insulin resistance are related to the development of colon cancer. Nuclear peroxisome proliferator-activated receptors (PPAR), which play a central role in lipid and glucose metabolism, had been hypothesized as being involved in colon cancerogenesis. In animal studies the lipid-lowering PPAR ligand bezafibrate suppressed colonic tumors. However, the effect of bezafibrate on colon cancer development in humans is unknown. Therefore, we proposed to investigate a possible preventive effect of bezafibrate on the development of colon cancer in patients with coronary artery disease during a 6-year follow-up.</p> <p>Methods</p> <p>Our population included 3011 patients without any cancer diagnosis who were enrolled in the randomized, double blind Bezafibrate Infarction Prevention (BIP) Study. The patients received either 400 mg of bezafibrate retard (1506 patients) or placebo (1505 patients) once a day. Cancer incidence data were obtained by matching a subject's identification numbers with the National Cancer Registry. Each matched record was checked for correct identification.</p> <p>Results</p> <p>Development of new cancer (all types) was recorded in 177 patients: in 79 (5.25%) patients from the bezafibrate group vs. 98 (6.51%) from the placebo group. Development of colon cancer was recorded in 25 patients: in 8 (0.53%) patients from the bezafibrate group vs. 17 (1.13%) from the placebo group, (Fisher's exact test: one side p = 0.05; two side p = 0.07).</p> <p>A difference in the incidence of cancer was only detectable after a 4 year lag and progressively increased with continued follow-up. On multivariable analysis the colon cancer risk in patients who received bezafibrate tended to be lower with a hazard ratio of 0.47 and 95% confidence interval 0.2–1.1.</p> <p>Conclusion</p> <p>Our data, derived from patients with coronary artery disease, support the hypothesis regarding a possible preventive effect of bezafibrate on the development of colon cancer.</p
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Multi-Alkali Photocathode Development at Brookhaven National Lab for Application in Superconducting Photoinjectors
The development of a suitable photocathode for use in a high average current photoinjector at temperatures ranging from 273 K down to 2 K is a subject of considerable interest, and active research. The choice of photocathode material is often a trade-off made based on the quantum efficiency of the cathode material, the tolerance to adverse vacuum conditions, and the laser wavelength needed to produce photoelectrons. In this paper an overview of the BNL work to date on CsK{sub 2}Sb photocathodes on a variety of substrates, irradiated at multiple wavelengths, and at temperatures down to 170 K will be discussed. The application of this photocathode material into a SRF photoinjector will also be discussed
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