2,665 research outputs found
Robust long-distance entanglement and a loophole-free Bell test with ions and photons
Two trapped ions that are kilometers apart can be entangled by the joint
detection of two photons, each coming from one of the ions, in a basis of
entangled states. Such a detection is possible with linear optical elements.
The use of two-photon interference allows entanglement distribution without
interferometric sensitivity to the path length of the photons. The present
method of creating entangled ions also opens up the possibility of a
loophole-free test of Bell's inequalities.Comment: published versio
Neutralization of B-Cell Activating Factor (BAFF) by Belimumab Reinforces Small Molecule Inhibitor Treatment in Chronic Lymphocytic Leukemia.
The introduction of idelalisib, ibrutinib and venetoclax for treatment of chronic lymphocytic leukemia (CLL) has greatly improved long term survival of patients. However, many patients do not achieve complete remission and suffer from development of resistance upon treatment with these small molecule inhibitors. Here we report that the TNF family member B-cell activating factor (BAFF) mediates resistance of CLL cells to idelalisib, ibrutinib and venetoclax by sustaining survival and preventing apoptosis of the malignant B cells as revealed by analysis of cellular ATP levels and mitochondrial membrane integrity as well as caspase activation, respectively. As BAFF also plays a prominent role in autoimmune diseases, the BAFF-neutralizing antibody belimumab was developed and approved for treatment of systemic lupus erythematosus (SLE). When we employed belimumab in the context of CLL treatment with idelalisib, ibrutinib and venetoclax, BAFF neutralization was found to significantly increase the sensitivity of the leukemic cells to all three small molecule inhibitors. Notably, BAFF neutralization proved to be beneficial independently of clinical stage according to Binet and Rai or IgVH mutational status. Our results identify drug repurposing of belimumab for neutralization of BAFF to complement small molecule inhibitor treatment as a promising therapeutic approach in CLL that is presently undergoing clinical evaluation
Metal semiconductor metal photodiodes based on all-epitaxial Ge-on-insulator-on-Si(111), grown by molecular beam epitaxy
We report on the fabrication and characterisation of an all-epitaxial Germanium-on-Insulator (GOI) Metal-Semiconductor-Metal (MSM) photodetector. The MSM photodetector is fabricated on a (111)-oriented epitaxial Ge layer, grown on an epitaxial Gd 2 O 3 /Si(111) substrate, by molecular beam epitaxy (MBE). The first step is the growth of the 15-nm thick Gd 2 O 3 epitaxial layer over CMOS-grade silicon, atop which an epitaxial layer of Ge is grown. Near infrared (NIR) MSM photodetectors have been fabricated over the Ge epitaxial layer with an inter-digitated (IDT) contact structure, with an active area of 100 μm x 124 μm. For the particular IDT dimensions, the dark current has been measured to be 475 μA. A responsivity of ∼ 2 mA/W is observed at a-5V bias, when excited at 1550 nm. © 2019 SPIE
Constraining the dark energy with galaxy clusters X-ray data
The equation of state characterizing the dark energy component is constrained
by combining Chandra observations of the X-ray luminosity of galaxy clusters
with independent measurements of the baryonic matter density and the latest
measurements of the Hubble parameter as given by the HST key project. By
assuming a spatially flat scenario driven by a "quintessence" component with an
equation of state we place the following limits on the
cosmological parameters and : (i) and (1) if the
equation of state of the dark energy is restricted to the interval (\emph{usual} quintessence) and (ii) and
() if violates the null energy condition and assume values (\emph{extended} quintessence or ``phantom'' energy). These results are in
good agreement with independent studies based on supernovae observations,
large-scale structure and the anisotropies of the cosmic background radiation.Comment: 6 pages, 4 figures, LaTe
Co2 efflux, co2 concentration and photosynthetic refixation in stems of Eucalyptus globulus (Labill.)
Research PaperIn spite of the importance of respiration in forest carbon budgets, the mechanisms by which physiological factors
control stem respiration are unclear. An experiment was set up in a Eucalyptus globulus plantation in central
Portugal with monoculture stands of 5-year-old and 10-year-old trees. CO2 efflux from stems under shaded and
unshaded conditions, as well as the concentration of CO2 dissolved in sap [CO2 *], stem temperature, and sap flow
were measured with the objective of improving our understanding of the factors controlling CO2 release from stems
of E. globulus. CO2 efflux was consistently higher in 5-year-old, compared with 10-year-old, stems, averaging 3.4
versus 1.3 mmol m22 s21, respectively. Temperature and [CO2 *] both had important, and similar, influences on the
rate of CO2 efflux from the stems, but neither explained the difference in the magnitude of CO2 efflux between trees
of different age and size. No relationship was found between efflux and sap flow, and efflux was independent of tree
volume, suggesting the presence of substantial barriers to the diffusion of CO2 from the xylem to the atmosphere in
this species. The rate of corticular photosynthesis was the same in trees of both ages and only reduced CO2 efflux by
7%, probably due to the low irradiance at the stem surface below the canopy. The younger trees were growing at
a much faster rate than the older trees. The difference between CO2 efflux from the younger and older stems appears
to have resulted from a difference in growth respiration rather than a difference in the rate of diffusion of xylemtransported
CO
Gammaretrovirus-mediated correction of SCID-X1 is associated with skewed vector integration site distribution in vivo
We treated 10 children with X-linked SCID (SCID-X1) using gammaretrovirus-mediated gene transfer. Those with sufficient follow-up were found to have recovered substantial immunity in the absence of any serious adverse events up to 5 years after treatment. To determine the influence of vector integration on lymphoid reconstitution, we compared retroviral integration sites (RISs) from peripheral blood CD3(+) T lymphocytes of 5 patients taken between 9 and 30 months after transplantation with transduced CD34(+) progenitor cells derived from 1 further patient and I healthy donor. Integration occurred preferentially in gene regions on either side of transcription start sites, was clustered, and correlated with the expression level in CD34(+) progenitors during transduction. In contrast to those in CD34(+) cells, RISs recovered from engrafted CD3(+)T cells were significantly overrepresented within or near genes encoding proteins with kinase or transferase activity or involved in phosphorus metabolism. Although gross patterns of gene expression were unchanged in transduced cells, the divergence of RIS target frequency between transduced progenitor cells and post-thymic T lymphocytes indicates that vector integration influences cell survival, engraftment, or proliferation
Coherent photon-photon interactions in very peripheral relativistic heavy ion collisions
Heavy ions at high velocities provide very strong electromagnetic fields for
a very short time. The main characteristics of ultraperipheral relativistic
heavy ion collisions are reviewed, characteristic parameters are identified.
The main interest in ultraperipheral heavy ion collisions at relativistic ion
colliders like the LHC is the interactions of very high energy (equivalent)
photons with the countermoving (equivalent) photons and hadrons (protons/ions).
The physics of these interactions is quite different from and complementary to
the physics of the strong fields achieved with current and future lasers.Comment: 5 pages, 5 figures, invited talk presented at the ELI Workshop and
School on Fundamental Physics with Ultra-high Fields (September 29- October
2, 2008, Frauenwoerth, German
Dyson-Schwinger Equations - aspects of the pion
The contemporary use of Dyson-Schwinger equations in hadronic physics is
exemplified via applications to the calculation of pseudoscalar meson masses,
and inclusive deep inelastic scattering with a determination of the pion's
valence-quark distribution function.Comment: 4 pages. Contribution to the Proceedings of ``DPF 2000,'' the Meeting
of the Division of Particles and Fields of the American Physical Society,
August 9-12, 2000, Department of Physics, the Ohio State University,
Columbus, Ohi
A device for feasible fidelity, purity, Hilbert-Schmidt distance and entanglement witness measurements
A generic model of measurement device which is able to directly measure
commonly used quantum-state characteristics such as fidelity, overlap, purity
and Hilbert-Schmidt distance for two general uncorrelated mixed states is
proposed. In addition, for two correlated mixed states, the measurement
realizes an entanglement witness for Werner's separability criterion. To
determine these observables, the estimation only one parameter - the visibility
of interference, is needed. The implementations in cavity QED, trapped ion and
electromagnetically induced transparency experiments are discussed.Comment: 6 pages, 3 figure
Co2 exchange and biomass development of the herbaceous vegetation in the portuguese montado ecosystem during spring
Montado are spatially heterogeneous ecosystems that are economically important for the production of
cork and herbaceous biomass that provide fodder for animals. Understanding of how trees and the
herbaceous layer interact to determine pasture yield and the overall CO2 exchange of the herbaceous
layer is crucial. Portable chamberswere used to study CO2 exchange by the herbaceous layer component
of the montado ecosystem in southern Portugal. Biomass, Net herbaceous layer CO2 exchange (NEE) and
respiration (Reco) were measured in the open and understory locations between March and May, during
the active growing period. Parameter fits on the NEE data were performed using empirical hyperbolic
light response model, while ecosystem respiration (Reco) data were fitted with a two-parameter
exponential model. Annual green biomass productions were 405.8 9.0 and 250.6 6.3 g m 2 in the
open and the understory, respectively. The respective maximum NEE during the day were 24.0 2.9 and
9.6 2.2 mmol m 2 s 1 while maximum Reco were 20.6 2.2 and 10.0 1.6 mmol m 2 s 1, occurring in
April. Photosynthetic photon flux density (PPFD) explained more that 70% of variations in daytime NEE while
soil temperature at 10 cm depth (Tsoil) explained >50% of the variations in Reco under non-limiting soil
moisture conditions. Both the herbaceous layer communities shared similar plant functional types and no
significant difference in nutrient nitrogen (N) occurred between them. The two herbaceous layer components
shared similar physiological characteristics and differences that arose in their CO2 uptake capacities and
green biomass production were the result of microclimatic differences created by tree shadin
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