431 research outputs found
Spectroscopic investigations of a Ti:Tm:LiNbO3 waveguide for photon-echo quantum memory
We report the fabrication and characterization of a
Ti:Tm:LiNbO optical waveguide in view of photon-echo quantum
memory applications. In particular, we investigated room- and
cryogenic-temperature properties via absorption, spectral hole burning, photon
echo, and Stark spectroscopy. We found radiative lifetimes of 82 s and 2.4
ms for the H and F levels, respectively, and a 44% branching
ratio from the H to the F level. We also measured an optical
coherence time of 1.6 s for the HH, 795 nm
wavelength transition, and investigated the limitation of spectral diffusion to
spectral hole burning. Upon application of magnetic fields of a few hundred
Gauss, we observed persistent spectral holes with lifetimes up to seconds.
Furthermore, we measured a linear Stark shift of 25 kHzcm/V. Our results
are promising for integrated, electro-optical, waveguide quantum memory for
photons.Comment: 11 pages, 14 figure
Autophagy limits proliferation and glycolytic metabolism in acute myeloid leukemia.
Decreased autophagy contributes to malignancies, however it is unclear how autophagy impacts on tumour growth. Acute myeloid leukemia (AML) is an ideal model to address this as (i) patient samples are easily accessible, (ii) the hematopoietic stem and progenitor population (HSPC) where transformation occurs is well characterized, and (iii) loss of the key autophagy gene Atg7 in hematopoietic stem and progenitor cells (HSPCs) leads to a lethal pre-leukemic phenotype in mice. Here we demonstrate that loss of Atg5 results in an identical HSPC phenotype as loss of Atg7, confirming a general role for autophagy in HSPC regulation. Compared to more committed/mature hematopoietic cells, healthy human and mouse HSCs displayed enhanced basal autophagic flux, limiting mitochondrial damage and reactive oxygen species in this long-lived population. Taken together, with our previous findings these data are compatible with autophagy limiting leukemic transformation. In line with this, autophagy gene losses are found within chromosomal regions that are commonly deleted in human AML. Moreover, human AML blasts showed reduced expression of autophagy genes, and displayed decreased autophagic flux with accumulation of unhealthy mitochondria indicating that deficient autophagy may be beneficial to human AML. Crucially, heterozygous loss of autophagy in an MLL-ENL model of AML led to increased proliferation in vitro, a glycolytic shift, and more aggressive leukemias in vivo. With autophagy gene losses also identified in multiple other malignancies, these findings point to low autophagy providing a general advantage for tumour growth
Impact of EMA regulatory label changes on hydroxyzine initiation, discontinuation and switching to other medicines in Denmark, Scotland, England and the Netherlands:an interrupted time series regression analysis
Background: Hydroxyzine is indicated for the management of anxiety, skin and sleep disorders. In 2015, the European Medicines Agency (EMA) concluded that hydroxyzine was pro-arrhythmogenic and changes to the product information were implemented in Europe. This study aimed to evaluate their impact in Denmark, Scotland, England and the Netherlands. Method: Quarterly time series analyses measuring hydroxyzine initiation, discontinuation, and switching to other antihistamines, benzodiazepines and antidepressants in Denmark, England, Scotland and the Netherlands from 2009 to 2018. Data were analysed using interrupted time series regression. Results: Hydroxyzine initiation in quarter one 2010 in Denmark, Scotland, England and the Netherlands per 100 000 was: 23.5, 91.5, 35.9 and 34.4 respectively. Regulatory action was associated with a significant: immediate fall in hydroxyzine initiation per 100 000 in England (−12.05, 95%CI −18.47 to −5.63) and Scotland (−19.01, 95%CI −26.99 to −11.02); change to a negative trend in hydroxyzine initiation per 100 000/quarter in England (−1.72, 95%CI −2.69 to −0.75) and Scotland (−2.38, 95%CI −3.32 to −1.44). Regulatory action was associated with a significant: immediate rise in hydroxyzine discontinuation per 100 000 in England (3850, 95%CI 440-7240). No consistent changes were observed in the Netherlands or Denmark. Regulatory action was associated with no switching to other antihistamines, benzodiazepines or antidepressants following hydroxyzine discontinuation in any country. Conclusion: The 2015 EMA regulatory action was associated with heterogeneous impact with reductions in hydroxyzine initiation varying by country. There was limited impact on discontinuation with no strong evidence suggesting unintended consequences of major switching to other antihistamines, benzodiazepines or antidepressants
Immune phenotype of patients with stage IV metastatic inflammatory breast cancer.
BACKGROUND: Inflammatory breast cancer (IBC) is a rare but aggressive carcinoma characterized by severe erythema and edema of the breast, with many patients presenting in advanced metastatic disease. The inflammatory nature is not due to classic immune-mediated inflammation, but instead results from tumor-mediated blockage of dermal lymphatic ducts. Previous work has shown that expression of PD-L1 on tumor cells can suppress T cell activation in triple-negative (TN) non-IBC breast cancer. In the present work, we investigated immune parameters in peripheral blood of metastatic IBC patients to determine whether cellular components of the immune system are altered, thereby contributing to pathogenesis of the disease. These immune parameters were also compared to PD-1 and PD-L1 expression in IBC tumor biopsies.
METHODS: Flow cytometry-based immune phenotyping was performed using fresh peripheral blood from 14 stage IV IBC patients and compared to 11 healthy age-similar control women. Immunohistochemistry for CD20, CD3, PD-1, and PD-L1 was performed on tumor biopsies of these metastatic IBC patients.
RESULTS: IBC patients with Stage IV disease had lymphopenia with significant reductions in circulating T, B, and NK cells. Reductions were observed in all subsets of CD4+ T cells, whereas reductions in CD8+ T cells were more concentrated in memory subsets. Immature cytokine-producing CD56bright NK cells expressed higher levels of FcγRIIIa and cytolytic granule components, suggesting accelerated maturation to cytolytic CD56dim cells. Immunohistochemical analysis of tumor biopsies demonstrated moderate to high expression of PD-1 in 18.2% of patients and of PD-L1 in 36.4% of patients. Interestingly, a positive correlation was observed between co-expression levels of PD-L1 and PD-1 in tumor biopsies, and higher expression of PD-L1 in tumor biopsies correlated with higher expression of cytolytic granule components in blood CD4+ T cells and CD56dim NK cells, and higher numbers of CD8+ effector memory T cells in peripheral blood. PD-1 expression in tumor also correlated with increased infiltration of CD20+ B cells in the tumor.
CONCLUSIONS: Our results suggest that while lymphocyte populations are severely compromised in stage IV IBC patients, an immune response toward the tumor had occurred in some patients, providing biological rationale to evaluate PD-1/PD-L1 immunotherapies for IBC
Observation of Exclusive Two-Body B Decays to Kaons and Pions
We have studied two-body charmless hadronic decays of B mesons into the final
states , , and . Using 3.3 million pairs
collected with the CLEO-II detector, we have made the first observation of the
decays , , and the sum of and decays (an average over charge-conjugate
states is always implied). We place upper limits on branching fractions for the
remaining decay modes.Comment: 9 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Study of Gluon versus Quark Fragmentation in and Events at \sqrt{s}=10 GeV
Using data collected with the CLEO II detector at the Cornell Electron
Storage Ring, we determine the ratio R(chrg) for the mean charged multiplicity
observed in Upsilon(1S)->gggamma events, to the mean charged multiplicity
observed in e+e- -> qqbar gamma events. We find R(chrg)=1.04+/-0.02+/-0.05 for
jet-jet masses less than 7 GeV.Comment: 15 pages, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Two-Body B Meson Decays to and -- Observation of {'}K$
In a sample of 6.6 million produced B mesons we have observed decays B ->
eta' K, with branching fractions BR(B+ -> eta' K+ = 6.5 +1.5 -1.4 +- 0.9) x
and BR(B0 -> eta' K0 = 4.7 +2.7 -2.0 +- 0.9) x . We have
searched with comparable sensitivity for 17 related decays to final states
containing an eta or eta' meson accompanied by a single particle or low-lying
resonance. Our upper limits for these constrain theoretical interpretations of
the B -> eta' K signal.Comment: 12 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
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