A versatile microarray platform for capturing rare cells

Analyses of rare events occurring at extremely low frequencies in body fluids are still challenging. We established a versatile microarray-based platform able to capture single target cells from large background populations. As use case we chose the challenging application of detecting circulating tumor cells (CTCs) - about one cell in a billion normal blood cells. After incubation with an antibody cocktail, targeted cells are extracted on a microarray in a microfluidic chip. The accessibility of our platform allows for subsequent recovery of targets for further analysis. The microarray facilitates exclusion of false positive capture events by co-localization allowing for detection without fluorescent labelling. Analyzing blood samples from cancer patients with our platform reached and partly outreached gold standard performance, demonstrating feasibility for clinical application. Clinical researchers free choice of antibody cocktail without need for altered chip manufacturing or incubation protocol, allows virtual arbitrary targeting of capture species and therefore wide spread applications in biomedical sciences

On Standard Reductions to Relative Gravity Measurements. A Case Study Through the Establishment of the New Local Gravity Net in the Province of Valencia (Spain)

This is an author's accepted manuscript of an article published in: “Survey Review"; Volume 43, Issue 319, 2011; copyright Taylor & Francis; available online at: http://dx.doi.org/10.1179/003962610X12747001420825Standard reductions to gravity readings due to Earth tides, ocean loading and attraction, polar motion, instrumental height and air pressure variations and loading of atmospheric masses are studied in this paper from a practical point of view, that is, taking into account their numerical values and their influence on gravimetric readings and relative gravimetric observations. The study was carried out using the observations and definition of a new local gravimetric net. This new local gravimetric net has been established in the province of Valencia (Eastern Spain) to meet the increasing requirements of geophysics, geology, geodesy and geodynamics. The net comprises 21 sites, which are an average of 45 km apart and was measured using Lacoste & Romberg D203 and G301 gravimeters. Gravity values were determined using one fixed station in relation to an absolute one and 202 relative gravimetric observables. Reductions are applied for Earth tides (with real accurate amplitude and phase-difference for the principal tidal waves analysed from 301 digitally recorded days of gravity readings) where oceanic attraction and loading has been considered. In addition, reductions for polar motion, vertical gradient to instrument height and air pressure and loading of atmospheric masses have been applied. The net was established using least square adjustment where the weights of each relative gravimetric observable were determined by iterative estimation in accordance with the Huber robust estimation procedure. Obtained standard deviations of the final gravity values have an average value of 18x10-8 ms-2 (18 µGal), minimum value of 10x10-8 ms-2 and maximum value of 26x10-8 ms-2 . The statistical analysis of the results concludes with a precision and reliability determination. Discussion of the numerical values obtained in the standard gravimetric reductions shows the importance of each one in the final solution, bearing in mind that the relative gravimetric observables have been obtained using Lacoste & Romberg instruments and the geographical location of the net. The main conclusion is that only Earth tides reduction (with approximate amplitude and phase-difference numbers for the principal tidal waves) have to be taken into accountMartín Furones, ÁE.; Anquela Julián, AB.; Padin Devesa, J.; Berné Valero, JL. (2011). On Standard Reductions to Relative Gravity Measurements. A Case Study Through the Establishment of the New Local Gravity Net in the Province of Valencia (Spain). Survey Review. 43(319):16-29. doi:10.1179/003962610X12747001420825S162943319Boedecker, G., & Richter, B. (1981). The new gravity base net 1976 of the Federal Republic of Germany (DSGN 76). Bulletin Géodésique, 55(3), 250-266. doi:10.1007/bf02530865Cartwright, D. E., & Tayler, R. J. (2007). New Computations of the Tide-generating Potential. Geophysical Journal of the Royal Astronomical Society, 23(1), 45-73. doi:10.1111/j.1365-246x.1971.tb01803.xCharles, K. and Hipkin, R.G. 1994. British precise gravity net 1993. Joint symposium of the International Gravity Comission and the International Geoid Comission, Symposium 113: 39–45, Graz, Austria. Ed. Springer-Verlag.Farrell, W. E. (1972). Deformation of the Earth by surface loads. Reviews of Geophysics, 10(3), 761. doi:10.1029/rg010i003p00761Jentzsch, G. (s. f.). Earth tides and ocean tidal loading. Lecture Notes in Earth Sciences, 145-171. doi:10.1007/bfb0011461Torge, W. 1989. Gravimetry. Ed. Walter de Gruyter, Berlin-New York. 465 pages.Wahr, J. M. (1985). Deformation induced by polar motion. Journal of Geophysical Research, 90(B11), 9363. doi:10.1029/jb090ib11p09363Wenzel, G. 1998. Format and structure for the exchange of high precision tidal data, http://www.ife.uni-hannover.de/∼Wenzel/format/format.html, acceded on February 1999

Heterocellular induction of interferon by negative-sense RNA viruses

The infection of cells by RNA viruses is associated with the recognition of virus PAMPs (pathogen-associated molecular patterns) and the production of type I interferon (IFN). To counter this, most, if not all, RNA viruses encode antagonists of the IFN system. Here we present data on the dynamics of IFN production and response during developing infections by paramyxoviruses, influenza A virus and bunyamwera virus. We show that only a limited number of infected cells are responsible for the production of IFN, and that this heterocellular production is a feature of the infecting virus as opposed to an intrinsic property of the cells

Star Formation and Dynamics in the Galactic Centre

The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A., 'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters