A Purcell-enabled monolayer semiconductor free-space optical modulator

Dephasing and non-radiative decay processes limit the performance of a wide variety of quantum devices at room temperature. Here we illustrate a general pathway to notably reduce the detrimental impact of these undesired effects through photonic design of the device electrodes. Our design facilitates a large Purcell enhancement that speeds up competing, desired radiative decay while also enabling convenient electrical gating and charge injection functions. We demonstrate the concept with a free-space optical modulator based on an atomically thin semiconductor. By engineering the plasmonic response of a nanopatterned silver gate pad, we successfully enhance the radiative decay rate of excitons in a tungsten disulfide monolayer by one order of magnitude to create record-high modulation efficiencies for this class of materials at room temperature. We experimentally observe a 10% reflectance change as well as 3 dB signal modulation, corresponding to a 20-fold enhancement compared with modulation using a suspended monolayer in vacuum. We also illustrate how dynamic control of light fields can be achieved with designer surface patterns. This research highlights the benefits of applying radiative decay engineering as a powerful tool in creating high-performance devices that complements substantial efforts to improve the quality of materials.</p

Production of resonances in a thermal model: invariant-mass spectra and balance functions

We present a calculation of the pi+ pi- invariant-mass correlations and the pion balance functions in the single-freeze-out model. A satisfactory agreement with the data for Au+Au collisions is found.Comment: Contribution to QM 2004 (4 pages, 2 figures

Directed flow of antiprotons in Au+Au collisions at AGS

Directed flow of antiprotons is studied in Au+Au collisions at a beam momentum of 11.5A GeV/c. It is shown that antiproton directed flow is anti-correlated to proton flow. The measured transverse momentum dependence of the antiproton flow is compared with predictions of the RQMD event generator.Comment: 16 pages, 6 figure

Human Cord Blood Stem Cell-Modulated Regulatory T Lymphocytes Reverse the Autoimmune-Caused Type 1 Diabetes in Nonobese Diabetic (NOD) Mice

Background: The deficit of pancreatic islet b cells caused by autoimmune destruction is a crucial issue in type 1 diabetes (T1D). It is essential to fundamentally control the autoimmunity for treatment of T1D. Regulatory T cells (Tregs) play a pivotal role in maintaining self-tolerance through their inhibitory impact on autoreactive effector T cells. An abnormality of Tregs is associated with initiation of progression of T1D. Methodology/Principal Findings: Here, we report that treatment of established autoimmune-caused diabetes in NOD mice with purified autologous CD4 + CD62L + Tregs co-cultured with human cord blood stem cells (CB-SC) can eliminate hyperglycemia, promote islet b-cell regeneration to increase b-cell mass and insulin production, and reconstitute islet architecture. Correspondingly, treatment with CB-SC-modulated CD4 + CD62L + Tregs (mCD4CD62L Tregs) resulted in a marked reduction of insulitis, restored Th1/Th2 cytokine balance in blood, and induced apoptosis of infiltrated leukocytes in pancreatic islets. Conclusions/Significance: These data demonstrate that treatment with mCD4CD62L Tregs can reverse overt diabetes

Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV

We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (|$\eta$|<0.8) and transverse momentum range 0.2< $p_{\rm T}$< 5.0 GeV/$c$. The elliptic flow signal v$_2$, measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 $\pm$ 0.002 (stat) $\pm$ 0.004 (syst) in the 40-50% centrality class. The differential elliptic flow v$_2(p_{\rm T})$ reaches a maximum of 0.2 near $p_{\rm T}$ = 3 GeV/$c$. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.Comment: 10 pages, 4 captioned figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/389

Broad-Spectrum Antiviral Therapeutics

Currently there are relatively few antiviral therapeutics, and most which do exist are highly pathogen-specific or have other disadvantages. We have developed a new broad-spectrum antiviral approach, dubbed Double-stranded RNA (dsRNA) Activated Caspase Oligomerizer (DRACO) that selectively induces apoptosis in cells containing viral dsRNA, rapidly killing infected cells without harming uninfected cells. We have created DRACOs and shown that they are nontoxic in 11 mammalian cell types and effective against 15 different viruses, including dengue flavivirus, Amapari and Tacaribe arenaviruses, Guama bunyavirus, and H1N1 influenza. We have also demonstrated that DRACOs can rescue mice challenged with H1N1 influenza. DRACOs have the potential to be effective therapeutics or prophylactics for numerous clinical and priority viruses, due to the broad-spectrum sensitivity of the dsRNA detection domain, the potent activity of the apoptosis induction domain, and the novel direct linkage between the two which viruses have never encountered.National Institute of Allergy and Infectious Diseases (U.S.) (grant AI057159)New England Regional Center of Excellence for Biodefense and Emerging Infectious DiseasesUnited States. Dept. of Defense (Director of Defense Research & Engineering)United States. Defense Threat Reduction AgencyUnited States. Defense Advanced Research Projects Agenc

Gate-tunable giant nonreciprocal charge transport in noncentrosymmetric oxide interfaces

A polar conductor, where inversion symmetry is broken, may exhibit directional propagation of itinerant electrons, i.e., the rightward and leftward currents differ from each other, when time-reversal symmetry is also broken. This potential rectification effect was shown to be very weak due to the fact that the kinetic energy is much higher than the energies associated with symmetry breaking, producing weak perturbations. Here we demonstrate the appearance of giant nonreciprocal charge transport in the conductive oxide interface, LaAlO3/SrTiO3, where the electrons are confined to two-dimensions with low Fermi energy. In addition, the Rashba spin???orbit interaction correlated with the sub-band hierarchy of this system enables a strongly tunable nonreciprocal response by applying a gate voltage. The observed behavior of directional response in LaAlO3/SrTiO3 is associated with comparable energy scales among kinetic energy, spin???orbit interaction, and magnetic field, which inspires a promising route to enhance nonreciprocal response and its functionalities in spin orbitronics

Effector and Naturally Occurring Regulatory T Cells Display No Abnormalities in Activation Induced Cell Death in NOD Mice

BACKGROUND: Disturbed peripheral negative regulation might contribute to evolution of autoimmune insulitis in type 1 diabetes. This study evaluates the sensitivity of naïve/effector (Teff) and regulatory T cells (Treg) to activation-induced cell death mediated by Fas cross-linking in NOD and wild-type mice. PRINCIPAL FINDINGS: Both effector (CD25(-), FoxP3(-)) and suppressor (CD25(+), FoxP3(+)) CD4(+) T cells are negatively regulated by Fas cross-linking in mixed splenocyte populations of NOD, wild type mice and FoxP3-GFP trangeneess. Proliferation rates and sensitivity to Fas cross-linking are dissociated in Treg cells: fast cycling induced by IL-2 and CD3/CD28 stimulation improve Treg resistance to Fas-ligand (FasL) in both strains. The effector and suppressor CD4(+) subsets display balanced sensitivity to negative regulation under baseline conditions, IL-2 and CD3/CD28 stimulation, indicating that stimulation does not perturb immune homeostasis in NOD mice. Effective autocrine apoptosis of diabetogenic cells was evident from delayed onset and reduced incidence of adoptive disease transfer into NOD.SCID by CD4(+)CD25(-) T cells decorated with FasL protein. Treg resistant to Fas-mediated apoptosis retain suppressive activity in vitro. The only detectable differential response was reduced Teff proliferation and upregulation of CD25 following CD3-activation in NOD mice. CONCLUSION: These data document negative regulation of effector and suppressor cells by Fas cross-linking and dissociation between sensitivity to apoptosis and proliferation in stimulated Treg. There is no evidence that perturbed AICD in NOD mice initiates or promotes autoimmune insulitis

APC Activation Restores Functional CD4+CD25+ Regulatory T Cells in NOD Mice that Can Prevent Diabetes Development

BACKGROUND: Defects in APC and regulatory cells are associated with diabetes development in NOD mice. We have shown previously that NOD APC are not effective at stimulating CD4(+)CD25(+) regulatory cell function in vitro. We hypothesize that failure of NOD APC to properly activate CD4(+)CD25(+) regulatory cells in vivo could compromise their ability to control pathogenic cells, and activation of NOD APC could restore this defect, thereby preventing disease. METHODOLOGY/PRINCIPAL FINDINGS: To test these hypotheses, we used the well-documented ability of complete Freund's adjuvant (CFA), an APC activator, to prevent disease in NOD mice. Phenotype and function of CD4(+)CD25(+) regulatory cells from untreated and CFA-treated NOD mice were determined by FACS, and in vitro and in vivo assays. APC from these mice were also evaluated for their ability to activate regulatory cells in vitro. We have found that sick NOD CD4(+)CD25(+) cells expressed Foxp3 at the same percentages, but decreased levels per cell, compared to young NOD or non-NOD controls. Treatment with CFA increased Foxp3 expression in NOD cells, and also increased the percentages of CD4(+)CD25(+)Foxp3(+) cells infiltrating the pancreas compared to untreated NOD mice. Moreover, CD4(+)CD25(+) cells from pancreatic LN of CFA-treated, but not untreated, NOD mice transferred protection from diabetes. Finally, APC isolated from CFA-treated mice increased Foxp3 and granzyme B expression as well as regulatory function by NOD CD4(+)CD25(+) cells in vitro compared to APC from untreated NOD mice. CONCLUSIONS/SIGNIFICANCE: These data suggest that regulatory T cell function and ability to control pathogenic cells can be enhanced in NOD mice by activating NOD APC