Science.gov

Sample records for wimp line sensitivity

  1. Development of bubble chambers with sensitivity to WIMPs

    NASA Astrophysics Data System (ADS)

    Bond, L.; Collar, J. I.; Ely, J.; Flake, M.; Hall, J.; Jordan, D.; Nakazawa, D.; Raskin, A.; Sonnenschein, A.; O'Sullivan, K.

    2005-01-01

    We constructed a small bubble chamber, with special features needed to search for WIMPs: long sensitive time periods, intrinsic insensitivity to minimum ionizing particles and target liquids with high sensitivity to both spin-dependent and -independent couplings. Stereo photography of bubbles allows rejection of events occuring at the chamber walls and discrimination of neutron backgrounds. The chamber can be operated with a variety of liquids, including CF 3Br, CF 3I, C 3F 8 and liquid xenon. A >60% live time fraction has been achieved and sensitivity to nuclear recoils demonstrated. Detectors of this type may be scalable to very large size at modest cost.

  2. Development of Bubble Chambers with Sensitivity to WIMPs

    SciTech Connect

    Bond, Leonard J.; Collar, J. I.; Ely, James H.; Flake, Matthew; Hall, Jason M.; Jordan, David V.; Nakazawa, Dante; Raskin, Aza; Sonnenschein, Andrew; Sullivan, Kelly O.

    2005-05-01

    Bubble nucleation in moderately superheated liquids can be triggered by nuclear recoils from WIMPs. This phenomenon is the basis for superheated droplet detectors. The droplet technique is currently limited by insensitivity to spin-independent interactions, due to lack of heavy elements in the usual target liquids, and sensitivity to contamination of the gel by alpha emitters. As an alternative, we have developed a new type of homogeneous bubble chamber, which can contain heavy liquids, including CF3Br, CF3I, and C3F8. Detectors of this type may be scalable to large size at modest cost and could have very low backgrounds. We discuss results obtained with a 12 ml prototype and plans for a 1 liter chamber.

  3. Development of Bubble Chambers with Sensitivity to WIMPs

    SciTech Connect

    Bond, Leonard J.; Collar, J. I.; Ely, James H.; Flake, Matthew; Hall, Jason M.; Jordan, David V.; Nakazawa, Dante; Raskin, Aza; Sonnenschein, Andrew; O'Sullivan, Kevin

    2005-01-10

    Bubble nucleation in moderately superheated liquids can be triggered by nuclear recoils from WIMPs. This phenomenon is the basis for superheated droplet detectors. The droplet technique is currently limited by insensitivity to spin-independent interactions, due to lack of heavy elements in the usual target liquids, and sensitivity to contamination of the gel by alpha emitters. As an alternative, we have developed a new type of homogeneous bubble chamber, which can contain heavy liquids, including CF3Br, CF3I, and C3F8. Detectors of this type may be scalable to large size at modest cost and could have very low backgrounds. We discuss results obtained with a 12 ml prototype and plans for a 1 liter chamber.

  4. Development of bubble chambers with sensitivity to WIMPs

    NASA Astrophysics Data System (ADS)

    Bond, L.; Collar, J. I.; Ely, J.; Flake, M.; Hall, J.; Jordan, D.; Nakazawa, D.; Raskin, A.; Sonnenschein, A.; Sullivan, K. O.

    2005-05-01

    Bubble nucleation in moderately superheated liquids can be triggered by nuclear recoils from WIMPs. This phenomenon is the basis for superheated droplet detectors. The droplet technique is currently limited by insensitivity to spin-independent interactions, due to lack of heavy elements in the usual target liquids, and sensitivity to contamination of the gel by alpha emitters. As an alternative, we have developed a new type of homogeneous bubble chamber, which can contain heavy liquids, including CF 3Br, CF 3I, and C 3F 8. Detectors of this type may be scalable to large size at modest cost and could have very low backgrounds. We discuss results obtained with a 12 ml prototype and plans for a 1 liter chamber.

  5. Development of bubble chambers with sensitivity to WIMPs , J. I. Collarb*

    E-print Network

    Development of bubble chambers with sensitivity to WIMPs L. Bonda , J. I. Collarb* , J. Elya , M@uchicago.edu We constructed a small bubble chamber, with special features needed to search for WIMPs: long of high- stability bubble chambers containing heavy liquids as an alternative to SDDs. The use of a stable

  6. Positron line radiation from halo WIMP annihilations as a dark matter signature

    NASA Technical Reports Server (NTRS)

    Turner, Michael S.; Wilczek, Frank

    1989-01-01

    We suggest a new signature for dark matter annihilation in the halo: high energy positron line radiation. Because the cosmic ray positron spectrum falls rapidly with energy, e+'s from halo WIMP annihilations can be a significant, clean signal for very massive WIMP's (approx. greater than 30 GeV). In the case that the e+e- annihilation channel has an appreciable branch, the e+ signal should be above background in a future detector, such as have been proposed for ASTROMAG, and of potential importance as a dark matter signature. A significant e+e- branching ratio can occur for neutralinos or Dirac neutrinos. High-energy, continuum positron radiation may also be an important signature for massive neutralino annihilations, especially near or above the threshold of the W+W- and ZoZo annihilation channels.

  7. Towards a depleted argon time projection chamber WIMP search: Darkside prototype analysis and predicted sensitivity

    NASA Astrophysics Data System (ADS)

    Loer, Ben Michael

    Scientists have now accumulated overwhelming evidence indicating that over 80% of the mass of the universe is in the form of dark matter, neutral particles with ultra-weak couplings to ordinary matter. One compelling candidate is a Weakly Interacting Massive Particle or WIMP, with mass on the order of 100 GeV.The signal of a WIMP interaction in a detector is a low energy (typically below ˜100 keV) recoiling atomic nucleus. The expected rate is at most a few interactions per year per ton of target. The most critical issue for direct WIMP searches is reducing the background in the detector below this very low rate. Argon is a promising target because measurements of the scintillation pulse shape and the scintillation-to-ionization ratio allow the reduction of gamma-induced signals, the largest source of background, by a factor of 108 or better. One of the major drawbacks of argon is the presence of radioactive 39Ar, which results in a decay rate of ˜1 Bq/kg in natural argon. Because 39Ar is produced primarily in the upper atmosphere, the 39Ar fraction can be reduced significantly by obtaining the argon from underground wells. Our collaboration, DarkSide, is developing a series of two-phase argon time projection chambers (TPCs) utilizing this depleted argon, along with passive shielding and active neutron and muon vetoes, for WIMP searches. I present results from a recent campaign of a 10 kg active mass prototype TPC that demonstrate the successful realization of many of the technical aspects necessary for a full-scale detector, in particular an electron-equivalent light yield of 4.5 photoelectrons per keV deposited, and a free electron lifetime in excess of 200 microseconds. Based on this successful prototype and Monte Carlo simulations, I then conclude that DarkSide-50, a 50 kg active mass TPC to be installed in LNGS, can likely acquire data background-free for three years, accumulating a fiducial exposure of ˜100 kg-years and reaching a sensitivity to the WIMP-nucleon cross section of ˜3x10 -45 cm2. I also present some details on the analysis of Borexino data that resulted in the first real-time, spectroscopic measurement of 7Be solar neutrino interactions.

  8. Extending the Sensitivity to the Detection of WIMP Dark Matter with an Improved Understanding of the Limiting Neutron Backgrounds

    SciTech Connect

    Kamat, Sharmila

    2005-01-01

    The Cryogenic Dark Matter Search (CDMS) uses position-sensitive Germanium and Silicon crystals in the direct detection of Weakly Interacting Massive Particles (WIMPs) believed to constitute most of the dark matter in the Universe. WIMP interactions with matter being rare, identifying and eliminating known backgrounds is critical for detection. Event-by-event discrimination by the detectors rejects the predominant gamma and beta backgrounds while Monte Carlo simulations help estimate, and subtract, the contribution from the neutrons. This thesis describes the effort to understand neutron backgrounds as seen in the two stages of the CDMS search for WIMPs. The first stage of the experiment was at a shallow site at the Stanford Underground Facility where the limiting background came from high-energy neutrons produced by cosmic-ray muon interactions in the rock surrounding the cavern. Simulations of this background helped inform the analysis of data from an experimental run at this site and served as input for the background reduction techniques necessary to set new exclusion limits on the WIMP-nucleon cross-section, excluding new parameter space for WIMPs of masses 8-20 GeV/c{sup 2}. This thesis considers the simulation methods used as well as how various event populations in the data served as checks on the simulations to allow them to be used in the interpretation of the WIMP-search data. The studies also confirmed the presence of a limiting neutron background at the shallow site, necessitating the move to the 713-meter deep Soudan Underground Facility. Similar computer-based studies helped quantify the neutron background seen at the deeper site and informed the analysis of the data emerging from the first physics run of the experiment at Soudan. In conjunction with the WIMP-search and calibration data, the simulations confirmed that increased depth considerably reduced the neutron backgrounds seen, greatly improving the sensitivity to WIMP detection. The data run set an upper limit of 4 x 10{sup -43} on the WIMP-nucleon cross section for a WIMP mass of 60 GeV/c{sup 2} . Upper limits to the rate of background neutrons have also been determined.

  9. Flavor sensitivity to theta_13 and the mass hierarchy for neutrinos from solar WIMP annihilation

    E-print Network

    Ralf Lehnert; Thomas J. Weiler

    2010-02-12

    The effect of the higher-energy 2nd resonance and the associated adiabatic-to-nonadiabatic transition on neutrino propagation in solar matter is presented. For WIMP-annihilation neutrinos injected with energies in the "sweet region" between 300 MeV and 10 GeV at the Sun's center, a significant and revealing dependence on the neutrino mass hierarchy and the mixing angle theta_13 down to 0.5 degrees is found in the flavor ratios arriving at Earth. In addition, the amplification of flavor ratios in the sweet region allows a better discrimination among possible annihilation modes of the solar dark matter. Under mild assumptions on WIMP properties, it is estimated that 200 neutrino events in the sweet region would be required for inferences of theta_13, the mass hierarchy, and the dominant WIMP annihilation mode. Future large-volume, low-energy neutrino detectors are likely needed if the measurement is to be made.

  10. Detection of and Experimental Constraints on WIMPs

    E-print Network

    California at Berkeley, University of

    68 Chapter 2 Detection of and Experimental Constraints on WIMPs 2.1 Introduction The indirect used to search for WIMP dark matter, which fall under the categories of indirect and direct detection the sensitivity of various detection methods. I focus on WIMPs in the context of the MSSM, though parts

  11. WIMPs search by means of the highly segmented scintillator

    E-print Network

    K. Fushimi; H. Kawasuso; M. Toi; E. Aihara; R. Hayami; S. Nakayama; N. Koori; R. Hazama; K. Ichihara; Y. Shichijo; S. Umehara; S. Yoshida

    2005-08-04

    The highly sensitive method to search for WIMPs dark matter particles is proposed. An array of thin NaI(Tl) plate has the great selectivity for distinguishing the WIMPs events and background ones. The principle of signal selection for WIMPs is described. The high sensitivity for SD (spin-dependent) type WIMPs is expected by applying multi-layer system of NaI(Tl) detector.

  12. Theoretical prospects for directional WIMP detection

    E-print Network

    O'Hare, Ciaran A J

    2015-01-01

    Direct detection of dark matter with directional sensitivity is a promising concept for improving the search for weakly interacting massive particles. With information on the direction of WIMP induced nuclear recoils one has access to the full 3-dimensional velocity distribution of the local dark matter halo and thus a potential avenue for studying WIMP astrophysics. Furthermore the unique angular signature of the WIMP recoil distribution provides a crucial discriminant from neutrinos which currently represent the ultimate background to direct detection experiments.

  13. Theoretical prospects for directional WIMP detection

    E-print Network

    Ciaran A. J. O'Hare

    2015-10-14

    Direct detection of dark matter with directional sensitivity is a promising concept for improving the search for weakly interacting massive particles. With information on the direction of WIMP induced nuclear recoils one has access to the full 3-dimensional velocity distribution of the local dark matter halo and thus a potential avenue for studying WIMP astrophysics. Furthermore the unique angular signature of the WIMP recoil distribution provides a crucial discriminant from neutrinos which currently represent the ultimate background to direct detection experiments.

  14. Dust Sensitivity of Absorption-Line Indices

    NASA Astrophysics Data System (ADS)

    MacArthur, Lauren A.

    2005-04-01

    We investigate the effects of dust extinction on integrated absorption-line indices that are widely used to derive constraints on the ages and metallicities of composite stellar systems. Typically, absorption-line studies have been performed on globular clusters or elliptical galaxies, which are mostly dust-free systems. However, many recent studies of integrated stellar populations have focused on spiral galaxies that may contain significant amounts of dust. It is almost universally assumed that the effects of dust extinction on absorption-line measurements are entirely negligible given the narrow baseline of the spectral features, but no rigorous study has yet been performed to verify this conjecture. In this analysis, we explore the sensitivity of the standard set of Lick absorption-line indices, the higher order Balmer line indices, the 4000 Å break, the near-IR calcium triplet indices, and the Rose indices to dust absorption according to population synthesis models that incorporate a multicomponent model for the line and continuum attenuation due to dust. The latter takes into account the finite lifetime of stellar birth clouds. While dust does not greatly affect the line-index measurements for single stellar populations, its effect can be significant for the 4000 Å break or when there is a significant amount of current star formation.

  15. Reporter cell lines for skin sensitization testing.

    PubMed

    Natsch, Andreas; Emter, Roger

    2015-10-01

    Skin sensitization has been described as an adverse outcome pathway (AOP), comprising a number of molecular events leading to the final adverse effect. In a new paradigm of toxicology, attempts are made to collect information using single mechanistic tests addressing different targets along such an AOP and to then integrate this information to arrive at a final toxicological prediction. This proposal is strongly influenced by the availability of methods for high-throughput screening of cellular events. Reporter cell lines are a particularly useful tool in such screening paradigms, as they can deliver highly reproducible and easily measureable results, and they can be designed to quantify induction or suppression at the transcription level of very specific molecular targets within cells. The first cell-based assay for skin sensitization, which has recently received ECVAM and OECD endorsement, is the reporter cell assay KeratinoSens™, reflecting activation of the Nrf2 pathway, and other assays measuring the Nrf2 pathway are under development or validation. An alternative approach (THP-G8) was recently developed based on activation of the Interleukin-8 gene. Here, we review these assays, their role in the AOP, their mechanistic interrelationships, their use for hazard and risk assessment, and their application in integrated testing strategies. At the same time, this study reviews (1) other cellular markers for sensitizers, and the potential to develop new reporter gene assays providing additional, non-redundant information, and (2) it presents approaches and new experimental data on attempts to further improve the predictivity of the existing assay. PMID:26194644

  16. Assessment of the NM-Lines Sensitivity for Measurement Errors

    NASA Astrophysics Data System (ADS)

    Monir, Michael; El-Refaei, Hatem; Khalil, Diaa; Omar, Omar

    In this work we investigate the sensitivity of the recently proposed NM-lines technique with respect to the error in the angle measurement in comparison with the conventional M-lines technique. The obtained results show that the NM-lines technique allows us to reduce the effect of the measurement errors and thus obtain better results for a given angular resolution.

  17. Isolation of two chloroethylnitrosourea-sensitive Chinese hamster cell lines

    SciTech Connect

    Hata, H.; Numata, M.; Tohda, H.; Yasui, A.; Oikawa, A. )

    1991-01-01

    1-((4-Amino-2-methylpyrimidin-5-yl)methyl)-3-(2-chloroethyl)-3- nitrosourea hydrochloride (ACNU), a cancer chemotherapeutic bifunctional alkylating agent, causes chloroethylation of DNA and subsequent DNA strand cross-linking through an ethylene bridge. We isolated and characterized two ACNU-sensitive mutants from mutagenized Chinese hamster ovary cells and found them to be new drug-sensitive recessive Chinese hamster mutants. Both mutants were sensitive to various monofunctional alkylating agents in a way similar to that of the parental cell lines CHO9. One mutant (UVS1) was cross-sensitive to UV and complemented the UV sensitivity of all Chinese hamster cell lines of 7 established complementation groups. Since UV-induced unscheduled DNA synthesis was very low, a new locus related to excision repair is thought to be defective in this cell line. Another ACNU-sensitive mutant, CNU1, was slightly more sensitive to UV than the parent cell line. CNU1 was cross-sensitive to 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea and slightly more sensitive to mitomycin C. No increased accumulation of ACNU and a low level of UV-induced unscheduled DNA synthesis in this cell as compared with the parental cell line suggest that there is abnormality in a repair response of this mutant cell to some types of DNA cross-links.

  18. E-WIMPs

    SciTech Connect

    Choi, Ki-Young; Roszkowski, Leszek

    2005-12-02

    Extremely weakly interacting massive particles (E-WIMPs) are intriguing candidates for cold dark matter in the Universe. We review two well motivated E-WIMPs, an axino and a gravitino, and point out their cosmological and phenomenological similarities and differences, the latter of which may allow one to distinguishing them in LHC searches for supersymmetry.

  19. Secluded WIMP Dark Matter

    E-print Network

    Maxim Pospelov; Adam Ritz; Mikhail B. Voloshin

    2007-11-30

    We consider a generic mechanism via which thermal relic WIMP dark matter may be decoupled from the Standard Model, namely through a combination of WIMP annihilation to metastable mediators with subsequent delayed decay to Standard Model states. We illustrate this with explicit examples of WIMPs connected to the Standard Model by metastable bosons or fermions. In all models, provided the WIMP mass is greater than that of the mediator, it can be secluded from the Standard Model with an extremely small elastic scattering cross-section on nuclei and rate for direct collider production. In contrast, indirect signatures from WIMP annihilation are consistent with a weak scale cross-section and provide potentially observable \\gamma-ray signals. We also point out that \\gamma-ray constraints and flavor physics impose severe restrictions on MeV-scale variants of secluded models, and identify limited classes that pass all the observational constraints.

  20. Sites of ozone sensitivity in diverse maize inbred lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropospheric ozone (O3) is an air pollutant that costs ~$14-26 billion in global crop losses and is projected to worsen in the future. Potential sites of O3 sensitivity in maize were tested by growing 200 inbred lines, including the nested association mapping population founder lines, under ambient...

  1. WIMP Dark Matter Christopher Rogan

    E-print Network

    Golwala, Sunil

    WIMP Dark Matter Christopher Rogan Ph135c - 04/27/07 #12;What is a WIMP? A. B. C. Weakly interacting massive particle #12;What is a WIMP? A. B. C. Weakly interacting massive particle #12;Evidence be nonrelativistic nonbaryonic matter · => Cold Dark Matter #12;WIMP candidates · Many theories for physics beyond

  2. Vector WIMP Miracle

    E-print Network

    Tomohiro Abe; Mitsuru Kakizaki; Shigeki Matsumoto; Osamu Seto

    2012-05-25

    Weakly interacting massive particle (WIMP) is well known to be a good candidate for dark matter, and it is also predicted by many new physics models beyond the standard model at the TeV scale. We found that, if the WIMP is a vector particle (spin one particle) which is associated with some gauge symmetry broken at the TeV scale, the higgs mass is often predicted to be 120--125 GeV, which is very consistent with the result of higgs searches recently reported by ATLAS and CMS collaborations at the Large Hadron Collider experiment. In this letter, we consider the vector WIMP using a non-linear sigma model in order to confirm this result as general as possible in a bottom-up approach. Near-future prospects to detect the vector WIMP at both direct and indirect detection experiments of dark matter are also discussed.

  3. Neutrinos from WIMP annihilations

    E-print Network

    Mattias Blennow

    2007-10-08

    We make an improved analysis on the flow of neutrinos originating from WIMP annihilations inside the Sun and the Earth. We treat both neutrino interaction and oscillation effects in a consistent framework. Our numerical simulations are performed in an event based setting, which is useful for both theoretical studies and for creating neutrino telescope Monte Carlos. We find that the flow of muon-type neutrinos is enhanced or suppressed depending on the dominant WIMP annihilation channel.

  4. WIMP Dark Matter Limit-Direct Detection Data and Sensitivity Plots from the Cryogenic Dark Matter Search II and the University of California at Santa Barbara

    DOE Data Explorer

    Expectations for non-baryonic dark matter are founded principally in Big Bang nucleosynthesis calculations, which indicate that the missing mass of the universe is not likely to be baryonic. The supersymmetric standard model (SUSY) offers a promising framework for expectations of particle species which could satisfy the observed properties of dark matter. WIMPs are the most likely SUSY candidate for a dark matter particle. The High Energy Physics Group at University of California, Santa Barbara, is part of the CDMSII Collaboration and have provided the Interactive Plotter for WIMP Dark Matter Limit-Direct Detection Data on their website. They invite other collaborations working on dark matter research to submit datasets and, as a result, have more than 150 data sets now available for use with the plotting tool. The published source of the data is provided with each data set.

  5. Radiation sensitivity of Merkel cell carcinoma cell lines

    SciTech Connect

    Leonard, J.H.; Ramsay, J.R.; Birrell, G.W.

    1995-07-30

    Merkel cell carcinoma (MCC), being a small cell carcinoma, would be expected to be sensitive to radiation. Clinical analysis of patients at our center, especially those with macroscopic disease, would suggest the response is quite variable. We have recently established a number of MCC cell lines from patients prior to radiotherapy, and for the first time are in a position to determine their sensitivity under controlled conditions. Some of the MCC lines grew as suspension cultures and could not be single cell cloned; therefore, it was not possible to use clonogenic survival for all cell lines. A tetrazolium based (MTT) assay was used for these lines, to estimate cell growth after {gamma} irradiation. Control experiments were conducted on lymphoblastoid cell lines (LCL) and the adherent MCC line, MCC13, to demonstrate that the two assays were comparable under the conditions used. We have examined cell lines from MCC, small cell lung cancer (SCLC), malignant melanomas, Epstein Barr virus (EBV) transformed lymphocytes (LCL), and skin fibroblasts for their sensitivity to {gamma} irradiation using both clonogenic cell survival and MTT assays. The results show that the tumor cell lines have a range of sensitivities, with melanoma being more resistant (surviving fraction at 2 Gy (SF2) 0.57 and 0.56) than the small cell carcinoma lines, MCC (SF2 range 0.21-0.45, mean SF2 0.30, n = 8) and SCLC (SF2 0.31). Fibroblasts were the most sensitive (SF2 0.13-0.20, mean 0.16, n = 5). The MTT assay, when compared to clonogenic assay for the MCC13 adherent line and the LCL, gave comparable results under the conditions used. Both assays gave a range of SF2 values for the MCC cell lines, suggesting that these cancers would give a heterogeneous response in vivo. The results with the two derivative clones of MCC14 (SF2 for MCC14/1 0.38, MCC14/2 0.45) would further suggest that some of them may develop resistance during clonogenic evolution. 25 refs., 3 figs., 1 tab.

  6. Nonthermal 'WIMP miracle'

    SciTech Connect

    Acharya, Bobby Samir; Kane, Gordon; Watson, Scott; Kumar, Piyush

    2009-10-15

    Light scalar fields with only gravitational strength couplings are typically present in UV complete theories of physics beyond the standard model. In the early universe it is natural for these fields to dominate the energy density, and their subsequent decay - if prior to big bang nucleosynthesis - will typically yield some dark matter particles in their decay products. In this paper we make the observation that a Nonthermal 'WIMP Miracle' may result: that is, in the simplest solution to the cosmological moduli problem, nonthermally produced WIMPs can naturally account for the observed dark matter relic density.

  7. Median recoil direction as a WIMP directional detection signal

    SciTech Connect

    Green, Anne M.; Morgan, Ben

    2010-03-15

    Direct detection experiments have reached the sensitivity to detect dark matter weakly interacting massive particles (WIMPs). Demonstrating that a putative signal is due to WIMPs, and not backgrounds, is a major challenge, however. The direction dependence of the WIMP scattering rate provides a potential WIMP 'smoking gun'. If the WIMP distribution is predominantly smooth, the Galactic recoil distribution is peaked in the direction opposite to the direction of Solar motion. Previous studies have found that, for an ideal detector, of order 10 WIMP events would be sufficient to reject isotropy, and rule out an isotropic background. We examine how the median recoil direction could be used to confirm the WIMP origin of an anisotropic recoil signal. Specifically, we determine the number of events required to confirm the direction of solar motion as the median inverse recoil direction at 95% confidence. We find that for zero background 31 events are required, a factor of {approx}2 more than are required to simply reject isotropy. We also investigate the effect of a nonzero isotropic background. As the background rate is increased the number of events required increases, initially fairly gradually and then more rapidly, once the signal becomes subdominant. We also discuss the effect of features in the speed distribution at large speeds, as found in recent high resolution simulations, on the median recoil direction.

  8. Patras Workshop on Axions, WIMPs and WISPs

    E-print Network

    9th Patras Workshop on Axions, WIMPs and WISPs Proceedings of the © Landeshauptstadt Mainz Editors Patras Workshop on Axions, WIMPs and WISPs 2013 June 24-28, 2013, Mainz, Germany Conference homepage http://axion-wimp2013.desy.de/ Slides at http://axion-wimp2013.desy.de/e201031/ Online proceedings at http://axion-wimp

  9. Direct and indirect detection of WIMPs

    E-print Network

    O. Martineau; for the EDELWEISS collaboration

    2001-07-26

    We present here the principles of detection of Weakly Interacting Massive Particles, which could represent a large contribution to Dark Matter. A status of the experimental situation is given both for indirect and direct detection. In particular, the DAMA claim for a WIMP signal is confronted to the recent results of the CDMS and EDELWEISS experiments. We conclude by comparing direct and indirect search sensitivities.

  10. Alignment Sensitivity Study of the St. ANA Beam Line

    NASA Astrophysics Data System (ADS)

    Gervais, Michelle; Couder, Manoel; Jung, Hyo Soon; Setoodehnia, Kiana

    2014-09-01

    The St. ANA (STable Accelerator for Nuclear Astrophysics) accelerator is being prepared for use with the St. George recoil mass separator. The accelerator is in working condition for use in direct kinematic experiments but the St. George separator works with inverse kinematics and requires a highly controlled beam restricted by severe position and divergence parameters that are not achieved at the present time. A systematic sensitivity study was conducted using a simulation of the beam line in order to assess the impact of a misalignment in each optical element or in the beam itself. Tests were done with the beam to analyze how the beam behaves at various points in the line and to compare this data with simulation results to determine possible causes of misalignment. The results of these tests and simulations are that the beam characteristics are now better understood and the possible causes of the limitations have been narrowed down. The St. ANA (STable Accelerator for Nuclear Astrophysics) accelerator is being prepared for use with the St. George recoil mass separator. The accelerator is in working condition for use in direct kinematic experiments but the St. George separator works with inverse kinematics and requires a highly controlled beam restricted by severe position and divergence parameters that are not achieved at the present time. A systematic sensitivity study was conducted using a simulation of the beam line in order to assess the impact of a misalignment in each optical element or in the beam itself. Tests were done with the beam to analyze how the beam behaves at various points in the line and to compare this data with simulation results to determine possible causes of misalignment. The results of these tests and simulations are that the beam characteristics are now better understood and the possible causes of the limitations have been narrowed down. Project advisor

  11. Combined Limits on WIMPs from the CDMS and EDELWEISS Experiments

    SciTech Connect

    Ahmed, Z.; Akerib, D.S.; Armengaud, E.; Arrenberg, S.; Augier, C.; Bailey, C.N.; Balakishiyeva, D.; Baudis, L.; Bauer, D.A.; Benoit, A.; Berge, L.; /CSNSM, Orsay /Karlsruhe U., EKP /Karlsruhe, Inst. Technol.

    2011-05-01

    The CDMS and EDELWEISS collaborations have combined the results of their direct searches for dark matter using cryogenic germanium detectors. The total data set represents 614 kg/days equivalent exposure. A straightforward method of combination was chosen for its simplicity before data were exchanged between experiments. The results are interpreted in terms of limits on spin-independent weakly interacting, massive particle (WIMP)-nucleon cross section. For a WIMP mass of 90 GeV/c{sup 2}, where this analysis is most sensitive, a cross section of 3.3 x 10{sup -44} cm{sup 2} is excluded at 90% C.L. At higher WIMP masses, the combination improves the individual limits, by a factor 1.6 above 700 GeV/c{sup 2}. Alternative methods of combining the data provide stronger constraints for some ranges of WIMP masses and weaker constraints for others.

  12. Stars of WIMPs

    E-print Network

    F. Pisano; J. L. Tomazelli

    1995-09-11

    A class of boson-fermion stars, whose spin-0 and spin-1/2 constituents interact through a U(1) current-current term in the Lagrangian density, is analysed. It is shown that it describes the low-energy behavior of a system of weakly interacting massive particles (WIMPs) from the leptonic sector of the minimal supersymmetric standard model. In this case the effective coupling constant $\\lambda$ is related to the Fermi constant $G_F$.

  13. Delay-Line Three-Dimensional Position Sensitive Radiation Detection

    NASA Astrophysics Data System (ADS)

    Jeong, Manhee

    High-resistivity silicon(Si) in large volumes and with good charge carrier transport properties has been produced and achieved success as a radiation detector material over the past few years due to its relatively low cost as well as the availability of well-established processing technologies. One application of that technology is in the fabrication of various position-sensing topologies from which the incident radiation's direction can be determined. We have succeeded in developing the modeling tools for investigating different position-sensing schemes and used those tools to examine both amplitude-based and time-based methods, an assessment that indicates that fine position-sensing can be achieved with simpler readout designs than are conventionally deployed. This realization can make ubiquitous and inexpensive deployment of special nuclear materials (SNM) detecting technology becomes more feasible because if one can deploy position-sensitive semiconductor detectors with only one or two contacts per side. For this purpose, we have described the delay-line radiation detector and its optimized fabrication. The semiconductor physics were simulated, the results from which guided the fabrication of the guard ring structure and the detector electrode, both of which included metal-field-plates. The measured improvement in the leakage current was confirmed with the fabricated devices, and the structures successfully suppressed soft-breakdown. We also demonstrated that fabricating an asymmetric strip-line structure successfully minimizing the pulse shaping and increases the distance through which one can propagate the information of the deposited charge distribution. With fabricated delay-line detectors we can acquire alpha spectra (Am-241) and gamma spectra (Ba-133, Co-57 and Cd-109). The delay-line detectors can therefore be used to extract the charge information from both ion and gamma-ray interactions. Furthermore, standard charge-sensitive circuits yield high SNR pulses. The detectors and existing electronics can therefore be used to yield imaging instruments for neutron and gamma-rays, in the case of silicon. For CZT, we would prefer to utilize current sensing to be able to clearly isolate the effects of the various charge-transport non-idealities, the full realization of which awaits the fabrication of the custom-designed TIA chip.

  14. Spin-Dependent WIMPs in DAMA?

    E-print Network

    Piero Ullio; Marc Kamionkowski; Petr Vogel

    2000-10-04

    We investigate whether the annual modulation observed in the DAMA experiment can be due to a weakly-interacting massive particle (WIMP) with an axial-vector (spin-dependent; SD) coupling to nuclei. We evaluate the SD WIMP-proton cross section under the assumption that such scattering accounts for the DAMA modulation, and we do the same for a SD WIMP-neutron cross section. We show that SD WIMP-proton scattering is ruled out in a model-independent fashion by null searches for energetic neutrinos from WIMP annihilation in the Sun, and that SD WIMP-neutron scattering is ruled out for WIMP masses > 20 GeV by the null result with the DAMA Xe detector. A SD WIMP with mass WIMP-neutron interaction is four orders of magnitude greater than the WIMP-proton interaction.

  15. Direct Detection Searches for WIMPs

    NASA Astrophysics Data System (ADS)

    Cabrera, Blas

    2014-03-01

    We have seen remarkable progress in direct detection searches for dark matter in the form of weakly interacting particles or WIMPs. Existing experiments using diverse technologies have set convincing limits for WIMPs under the spin independent interaction framework and have ruled out much of the phase space suggested by supersymmetric models. Liquid xenon experiments have provided the best limits for masses above 6 GeV/c2, with cryogenic detectors and bubble chambers setting the best limits for lighter mass WIMPs. In tension with the liquid xenon experiments are hints of signals and a claimed detection in the light WIMP mass sector. A number of theoretical ideas are consistent with light mass WIMPs, and a general approach, which probes all possible interactions between WIMPs and nucleons, stresses the need for a variety of target nuclei with the lowest possible thresholds to broadly cover the possibilities. As discussed extensively in P5 meetings, the down selection process for the second generation experiments (G2) will determine the progress over the next decade. As a community, we have asked the agencies for significant additional funds to be identified so that several G2 experiments can move forward and R&D on others continue. We need to continue this important search aggressively until we find WIMPs or reach the natural floor where the solar and atmospheric neutrinos become an irreducible background.

  16. The WIMP Forest: Indirect Detection of a Chiral Square

    SciTech Connect

    Bertone, Gianfranco; Jackson, C.B.; Shaughnessy, Gabe; Tait, Tim M.P.; Vallinotto, Alberto

    2009-04-01

    The spectrum of photons arising from WIMP annihilation carries a detailed imprint of the structure of the dark sector. In particular, loop-level annihilations into a photon and another boson can in principle lead to a series of lines (a WIMP forest) at energies up to the WIMP mass. A specific model which illustrates this feature nicely is a theory of two universal extra dimensions compactified on a chiral square. Aside from the continuum emission, which is a generic prediction of most dark matter candidates, we find a 'forest' of prominent annihilation lines that, after convolution with the angular resolution of current experiments, leads to a distinctive (2-bump plus continuum) spectrum, which may be visible in the near future with the Fermi Gamma-Ray Space Telescope (formerly known as GLAST).

  17. 47 CFR 69.713 - Common line, traffic-sensitive, and tandem-switched transport services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Common line, traffic-sensitive, and tandem-switched transport...Flexibility § 69.713 Common line, traffic-sensitive, and tandem-switched transport...and 69.154. (2) Services in the traffic-sensitive basket, as described...

  18. WIMP-nucleon scattering with heavy WIMP effective theory

    E-print Network

    Richard J. Hill; Mikhail P. Solon

    2014-06-05

    The discovery of a Standard Model-like Higgs boson and the hitherto absence of evidence for other new states may indicate that if WIMPs comprise cosmological dark matter, they are heavy compared to electroweak scale particles, $M \\gg m_{W^\\pm}, m_{Z^0}$. In this limit, the absolute cross section for a WIMP of given electroweak quantum numbers to scatter from a nucleon becomes computable in terms of Standard Model parameters. We develop effective field theory techniques to analyze the heavy WIMP limit of WIMP-nucleon scattering, and present the first complete calculation of the leading spin-independent cross section in Standard Model extensions consisting of one or two electroweak $SU(2)_W \\times U(1)_Y$ multiplets.

  19. The fraternal WIMP miracle

    NASA Astrophysics Data System (ADS)

    Craig, Nathaniel; Katz, Andrey

    2015-10-01

    We identify and analyze thermal dark matter candidates in the fraternal twin Higgs model and its generalizations. The relic abundance of fraternal twin dark matter is set by twin weak interactions, with a scale tightly tied to the weak scale of the Standard Model by naturalness considerations. As such, the dark matter candidates benefit from a ``fraternal WIMP miracle'', reproducing the observed dark matter abundance for dark matter masses between 50 and 150 GeV . However, the couplings dominantly responsible for dark matter annihilation do not lead to interactions with the visible sector. The direct detection rate is instead set via fermionic Higgs portal interactions, which are likewise constrained by naturalness considerations but parametrically weaker than those leading to dark matter annihilation. The predicted direct detection cross section is close to current LUX bounds and presents an opportunity for the next generation of direct detection experiments.

  20. Stringy WIMP Detection and Annihilation

    E-print Network

    James A. Maxin; Van E. Mayes; Dimitri V. Nanopoulos

    2009-06-17

    We calculate the direct dark matter detection spin-independent and proton spin-dependent cross-sections for a semi-realistic intersecting D6-brane model. The cross-sections are compared to the latest constraints of the current dark matter direct detection experiments, as well as the projected results of future dark matter experiments. The allowed parameter space of the intersecting D6-brane model is shown with all current experimental constraints, including those regions satisfying the WMAP and Supercritical String Cosmology (SSC) limits on the dark matter density in the universe. Additionally, we compute the indirect detection gamma-ray flux resulting from neutralino annihilation for the D6-brane model and compare the flux to the projected sensitivity of the Fermi Gamma-ray Space Telescope. Finally, we compute the direct and indirect detection cross-sections as well as the gamma-ray flux resulting from WIMP annihilations for the one-parameter model for comparison, where the one-parameter model is a highly constrained subset of the mSUGRA parameter space such that the soft supersymmetry breaking terms are functions of the common gaugino mass, which is common to many string compactifications.

  1. Probing WIMP particle physics and astrophysics with direct detection and neutrino telescope data

    NASA Astrophysics Data System (ADS)

    Kavanagh, Bradley J.; Fornasa, Mattia; Green, Anne M.

    2015-05-01

    With positive signals from multiple direct detection experiments, it will, in principle, be possible to measure the mass and cross sections of weakly interacting massive particle (WIMP) dark matter. Recent work has shown that, with a polynomial parametrization of the WIMP speed distribution, it is possible to make an unbiased measurement of the WIMP mass, without making any astrophysical assumptions. However, direct detection experiments are not sensitive to low-speed WIMPs and, therefore, any model-independent approach will lead to a bias in the cross section. This problem can be solved with the addition of measurements of the flux of neutrinos from the Sun. This is because the flux of neutrinos produced from the annihilation of WIMPs which have been gravitationally captured in the Sun is sensitive to low-speed WIMPs. Using mock data from next-generation direct detection experiments and from the IceCube neutrino telescope, we show that the complementary information from IceCube on low-speed WIMPs breaks the degeneracy between the cross section and the speed distribution. This allows unbiased determinations of the WIMP mass and spin-independent and spin-dependent cross sections to be made, and the speed distribution to be reconstructed. We use two parametrizations of the speed distribution: binned and polynomial. While the polynomial parametrization can encompass a wider range of speed distributions, this leads to larger uncertainties in the particle physics parameters.

  2. COUPP, A Heavy-Liquid Bubble Chamber for WIMP Detection

    NASA Astrophysics Data System (ADS)

    Bolte, J.; Collar, J. I.; Crisler, M.; Holmgren, D.; Nakazawa, D.; Odom, B.; O'Sullivan, K.; Plunkett, R.; Ramberg, E.; Raskin, A.; Sonnenschein, A.; Vieira, J.

    2005-04-01

    The capabilities and reach of the first phase of COUPP (the Chicago Observatory for Underground Particle Physics) are described. During this first phase of the experiment a 2 kg CF3I bubble chamber sensitive to WIMPs will be operated at the ~300 m.w.e. of the Minos-near gallery at FNAL. Prospects for larger devices are briefly discussed.

  3. Light WIMPs in the Sun: Constraints from helioseismology

    SciTech Connect

    Cumberbatch, Daniel T.; Guzik, Joyce A.; Silk, Joseph; Watson, L. Scott; West, Stephen M.

    2010-11-15

    We calculate solar models including dark matter (DM) weakly interacting massive particles (WIMPs) of mass 5-50 GeV and test these models against helioseismic constraints on sound speed, convection-zone depth, convection-zone helium abundance, and small separations of low-degree p-modes. Our main conclusion is that both direct detection experiments and particle accelerators may be complemented by using the Sun as a probe for WIMP DM particles in the 5-50 GeV mass range. The DM most sensitive to this probe has suppressed annihilations and a large spin-dependent elastic scattering cross section. For the WIMP cross section parameters explored here, the lightest WIMP masses <10 GeV are ruled out by constraints on core sound speed and low-degree frequency spacings. For WIMP masses 30-50 GeV, the changes to the solar structure are confined to the inner 4% of the solar radius and so do not significantly affect the solar p-modes. Future helioseismology observations, most notably involving g-modes, and future solar neutrino experiments may be able to constrain the allowable DM parameter space in a mass range that is of current interest for direct detection.

  4. Spin-dependent WIMP limits from a bubble chamber.

    PubMed

    Behnke, E; Collar, J I; Cooper, P S; Crum, K; Crisler, M; Hu, M; Levine, I; Nakazawa, D; Nguyen, H; Odom, B; Ramberg, E; Rasmussen, J; Riley, N; Sonnenschein, A; Szydagis, M; Tschirhart, R

    2008-02-15

    Bubble chambers were the dominant technology used for particle detection in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on a new application for these devices. We operated an ultraclean, room-temperature bubble chamber containing 1.5 kilograms of superheated CF3I, a target maximally sensitive to spin-dependent and -independent weakly interacting massive particle (WIMP) couplings. An extreme intrinsic insensitivity to the backgrounds that commonly limit direct searches for dark matter was measured in this device under operating conditions leading to the detection of low-energy nuclear recoils like those expected from WIMPs. Improved limits on the spin-dependent WIMP-proton scattering cross section were extracted during our experiments, excluding this type of coupling as a possible explanation for a recent claim of particle dark-matter detection. PMID:18276885

  5. Direct Detection of Multi-component Secluded WIMPs

    E-print Network

    Brian Batell; Maxim Pospelov; Adam Ritz

    2009-03-19

    Dark matter candidates comprising several sub-states separated by a small mass gap, and coupled to the Standard Model by (sub-)GeV force carriers, can exhibit non-trivial scattering interactions in direct detection experiments. We analyze the secluded U(1)-mediated WIMP scenario, and calculate the elastic and inelastic cross sections for multi-component WIMP scattering off nuclei. We find that second-order elastic scattering, mediated by virtual excited states, provides strong sensitivity to the parameters of the model for a wide range of mass splittings, while for small splittings the WIMP excited states have lifetimes exceeding the age of the universe, and generically have a fractional relative abundance above 0.1%. This generates even stronger constraints for mass splittings less than 200 keV due to exothermic de-excitation events in detectors.

  6. Direct WIMP searches with XENON100 and XENON1T

    NASA Astrophysics Data System (ADS)

    Alfredo Davide, Ferella

    2015-05-01

    The XENON100 experiment is the second phase of the XENON direct Dark Matter search program. It consists of an ultra-low background double phase (liquid-gas) xenon filled time projection chamber with a total mass of 161 kg (62 in the target region and 99 in the active shield), installed at the Laboratori Nazionali del Gran Sasso (LNGS). Here the results from the 224.6 live days of data taken between March 2011 and April 2012 are reported. The experiment set one of the most stringent limits on the WIMP-nucleon spin-independent cross section to date (2 × 10-45 cm2 for a 55 Gev/c2 WIMP mass at 90 % confidence level) and the most stringent on the spin-dependent WIMP-neutron interaction (3.5 × 10-40 for a 45 GeV/c2 WIMP mass). With the same dataset, XENON100 excludes also solar axion coupling to electrons at gAe > 7.7 × 10-12 for a mass of mAxion <1 keV/c2 and galactic axion couplings by gAe > 1 × 10-12 at a mass range of mAxion = 5-10 keV/c2 (both 90 % C.L.). Moreover an absolute spectral comparison between simulated and measured nuclear recoil distributions of light and charge signals from a 241AmBe source demonstrates a high level of detector and systematics understanding. Finally, the third generation of the XENON experiments, XENON1T, is the first tonne scale direct WIMP search experiment currently under construction. The commissioning phase of XENON1T is expected to start in early 2015 followed, a few months after, by the first science run. The experiment will reach sensitivities on the WIMP-nucleon spin-independent cross section down to 2 ×10-47 cm2 after two years of data taking.

  7. Dark matter in the Solar System. II. WIMP annihilation rates in the Sun

    SciTech Connect

    Peter, Annika H. G.

    2009-05-15

    We calculate the annihilation rate of weakly interacting massive particles (WIMPs) in the Sun as a function of their mass and elastic scattering cross section. One byproduct of the annihilation, muon neutrinos, may be observed by the next generation of neutrino telescopes. Previous estimates of the annihilation rate assumed that any WIMPs from the Galactic dark halo that are captured in the Sun by elastic scattering off solar nuclei quickly reach thermal equilibrium in the Sun. Using simulations of WIMP orbits in the Solar System in the case that spin-independent scattering dominates in the Sun (and extrapolating to the case when spin-dependent scattering dominates), we show that the optical depth of the Sun to WIMPs and the gravitational forces from planets both serve to decrease the annihilation rate below these estimates. While we find that the sensitivity of upcoming km{sup 3}-scale neutrino telescopes to {approx}100 GeV WIMPs is virtually unchanged from previous estimates, the sensitivity of these experiments to {approx}10 TeV WIMPs may be an order of magnitude less than the standard calculations would suggest. The new estimates of the annihilation rates should guide future experiment design and improve the mapping from neutrino event rates to WIMP parameter space.

  8. Event rates for WIMP detection

    SciTech Connect

    Vergados, J. D.; Moustakidis, Ch. C.; Oikonomou, V.

    2006-11-28

    The event rates for the direct detection of dark matter for various types of WIMPs are presented. In addition to the neutralino of SUSY models, we considered other candidates (exotic scalars as well as particles in Kaluza-Klein and technicolour theories) with masses in the TeV region. Then one finds reasonable branching ratios to excited states. Thus the detection of the WIMP can be made not only by recoil measurements, by measuring the de-excitation {gamma}-rays as well.

  9. 9-{beta}-arabinofuranosyladenine preferentially sensitizes radioresistant squamous cell carcinoma cell lines to x-rays

    SciTech Connect

    Heaton, D.; Mustafi, R.; Schwartz, J.L. |

    1992-06-01

    The effect of 9-{beta}-arabinofuranosyladenine (ara-A) on sensitivity to the deleterious effects of x-rays was studied in six squamous cell carcinoma cell lines. Three lines were relatively radioresistant, having D{sub 0} values of 2.31 to 2.89 Gy, and the other three lines were relatively radiosensitive, having D{sub 0} values of between 1.07 and 1.45 Gy. Ara-A (50 or 500 {mu}M) was added to cultures 30 min prior to irradiation and removed 30 min after irradiation, and sensitivity was measured in terms of cell survival. The radiosensitizing effect of ara-A was very dependent on the inherent radiosensitivity of the tumor cell line. Fifty micromolar concentrations of ara-A sensitized only the two most radioresistant lines, SCC-12B.2 and JSQ-3. Five hundred micromolar concentrations of ara-A sensitized the more sensitive cell lines, SQ-20B and SQ-9G, but failed to have any effect on the radiation response of the two most sensitive cell lines, SQ-38 and SCC-61. Concentrations of ara-A as low as 10 {mu}M were equally efficient in inhibiting DNA synthesis in all six cell lines. These results suggest that the target for the radiosensitizing effect of ara-A is probably related to the factor controlling the inherent radiosensitivity of human tumor cells. Therefore, ara-A might be useful in overcoming radiation resistance in vivo.

  10. Preliminary results of a WIMP search with EDELWEISS-II cryogenic detectors

    E-print Network

    E. Armengaud; for the EDELWEISS collaboration

    2010-11-10

    The EDELWEISS-II experiment uses cryogenic heat-and-ionization detectors in order to detect the rare interactions from possible WIMP dark matter particles on Germanium nuclei. Recently, new-generation detectors with an interleaved electrode geometry were developped and validated, enabling an outstanding rejection of gamma-rays and surface interactions. We present here preliminary results of a one-year WIMP search carried out with ten of such detectors in the Laboratoire Souterrain de Modane. A sensitivity to the spin-independent WIMP-nucleon cross-section of 5 \\times 10-8 pb was achieved using a 322 kg

  11. Direct and Indirect Searches for Dark Matter in the Form of Weakly Interacting Massive Particles (WIMPs)

    E-print Network

    Nader Mirabolfathi

    2004-12-03

    Numerous lines of evidence indicate that the matter content of the Universe is dominated by some unseen component. Determining the nature of this Dark Matter is one of the most important problems in cosmology. Weakly Interacting Massive Particles (WIMPs) are widely considered to be one of the best candidates which may comprise the Dark Matter. A brief overview of the different methods being used to search for WIMP Dark Matter is given, focusing on the technologies of several benchmark experiments.

  12. Light WIMPs And Equivalent Neutrinos

    E-print Network

    Gary Steigman; Kenneth M. Nollett

    2014-02-21

    Very light WIMPs (chi), thermal relics that annihilate late in the early Universe, change the energy and entropy densities at BBN and at recombination. BBN, in combination with the CMB, can remove some of the degeneracies among light WIMPs and equivalent neutrinos, constraining the existence and properties of each. Depending on the nature of the light WIMP (Majorana or Dirac fermion, real or complex scalar) the joint BBN + CMB analyses set lower bounds to m_chi in the range 0.5 - 5 MeV (m_chi/m_e > 1 - 10), and they identify best fit values for m_chi in the range 5 - 10 MeV. The joint BBN + CMB analysis finds a best fit value for the number of equivalent neutrinos, Delta N_nu ~ 0.65, nearly independent of the nature of the WIMP. In the absence of a light WIMP (m_chi > 20 MeV), N_eff = 3.05(1 + Delta N_nu /3). In this case, there is excellent agreement between BBN and the CMB, but the joint fit reveals Delta N_nu = 0.40+-0.17, disfavoring standard big bang nucleosynthesis (SBBN) (Delta N_nu = 0) at ~ 2.4 sigma, as well as a sterile neutrino (Delta N_nu = 1) at ~ 3.5 sigma. The best BBN + CMB joint fit disfavors the absence of dark radiation (Delta N_nu = 0 at ~ 95% confidence), while allowing for the presence of a sterile neutrino (Delta N_nu = 1 at ~ 1 sigma). For all cases considered here, the lithium problem persists. These results, presented at the TAUP 2013 Conference, are based on Nollett & Steigman (2013).

  13. WIMPs and Un-Naturalness

    E-print Network

    Luca Vecchi

    2014-09-29

    The WIMP "miracle" suggests a new physics threshold ranging from the weak scale up to several tens of TeVs. Obtaining the correct dark matter density in many theories aiming to solve the hierarchy problem may thus require some amount of tuning of the weak scale, hinting at a possible connection between WIMP dark matter and unnaturalness. We point out that dark matter direct detection is a very efficient probe of these unnatural models, and that existing data already provide important clues to the nature of the associated WIMPs. We present a model-independent, relativistic analysis of the signatures of a gauge-singlet dark matter candidate of arbitrary spin, and discuss the current experimental bounds from LUX and XENON100. For complex WIMPs, dark matter direct detection is complementary to electroweak precision tests, and can even compete with flavor constraints if the dark matter has spin. Particularly relevant for future searches are couplings to the Higgs mass operator, which are expected to be large if the electroweak scale is finely tuned. Care is devoted to the RG evolution of the effective Lagrangian. We find that the CP-even scalar coupling to charm quarks is enhanced by about 20% compared to the one-loop estimate. When pushed in the unnatural regime, warped extra dimensions -- with or without custodial symmetry -- become attractive theories for flavor, the Higgs mass, and dark matter. The WIMP argument basically sets an upper bound on unnaturalness, whereas direct detection experiments select scalar or real particles as the most compelling dark matter candidates.

  14. Dark Matter: Looking for WIMPs in the Galactic Halo

    NASA Astrophysics Data System (ADS)

    Akerib, Daniel S.

    2006-07-01

    Overwhelming observational evidence indicates that most of the matter in the Universe consists of non-baryonic dark matter. One possibility is that the dark matter is Weakly-Interacting Massive Particles (WIMPs) that were produced in the early Universe. These relics could comprise the Milky Way's dark halo and provide evidence for new particle physics, such as Supersymmetry. After reviewing some of the evidence for dark matter and the WIMP hypothesis, I will describe the strategy for searching for WIMPs, along with a survey of the current status and outlook. In particular, dark matter searches have begun to explore the region of parameter space where SUSY particles could provide dark matter candidates. I will also mention some of the recent theoretical work on dark matter candidates which is being done in anticipation of the turn-on of the LHC and as part of the active R&D on the ILC. Finally, a vigorous detector development program promises significant advances in WIMP sensitivity in the coming years.

  15. Dark Matter: Looking for WIMPs in the Galactic Halo

    SciTech Connect

    Akerib, Daniel S.

    2006-07-11

    Overwhelming observational evidence indicates that most of the matter in the Universe consists of non-baryonic dark matter. One possibility is that the dark matter is Weakly-Interacting Massive Particles (WIMPs) that were produced in the early Universe. These relics could comprise the Milky Way's dark halo and provide evidence for new particle physics, such as Supersymmetry. After reviewing some of the evidence for dark matter and the WIMP hypothesis, I will describe the strategy for searching for WIMPs, along with a survey of the current status and outlook. In particular, dark matter searches have begun to explore the region of parameter space where SUSY particles could provide dark matter candidates. I will also mention some of the recent theoretical work on dark matter candidates which is being done in anticipation of the turn-on of the LHC and as part of the active R and D on the ILC. Finally, a vigorous detector development program promises significant advances in WIMP sensitivity in the coming years.

  16. Trust and Profit Sensitive Ranking for the Deep Web and On-line Advertisements

    E-print Network

    Kambhampati, Subbarao

    Trust and Profit Sensitive Ranking for the Deep Web and On-line Advertisements by Raju Balakrishnan of ranking the deep web data considering trustworthiness and relevance. I address the end-to-end deep web ranking by focusing on: (i) ranking and selection of the deep web databases (ii) topic sensitive ranking

  17. Photon spectra from WIMP annihilation

    SciTech Connect

    Cembranos, J. A. R.; Cruz-Dombriz, A. de la; Dobado, A.; Maroto, A. L.; Lineros, R. A.

    2011-04-15

    If the present dark matter in the Universe annihilates into standard model particles, it must contribute to the fluxes of cosmic rays that are detected on the Earth and, in particular, to the observed gamma-ray fluxes. The magnitude of such a contribution depends on the particular dark matter candidate, but certain features of the produced photon spectra may be analyzed in a rather model-independent fashion. In this work we provide the complete photon spectra coming from WIMP annihilation into standard model particle-antiparticle pairs obtained by extensive Monte Carlo simulations. We present results for each individual annihilation channel and provide analytical fitting formulas for the different spectra for a wide range of WIMP masses.

  18. Limits on GeV-scale WIMPs using charge signals in XENON100

    NASA Astrophysics Data System (ADS)

    Wall, Richard

    2014-03-01

    Various theoretical models and recent experimental results have led to growing interest in the search for WIMP-like dark matter in the mass range of a few GeV. One important class of detector used in this study is based on the liquid-gas, dual-phase Xenon time projection chamber (as in XENON100 and LUX). These detectors nominally use both scintillation (S1) and ionization (S2) signals to localize collision events in their sensitive volumes and thus reject background events, but it is known that the efficiency for detecting small S1 signals (such as are expected from a GeV-scale WIMP interaction) is much smaller than the efficiency for detecting an S2 from the same recoil. By removing the requirement of an observed S1 signal, one can thus effectively lower the energy threshold of the detector, and study GeV-scale WIMPs with greater sensitivity. With this in mind, we measure the rate of WIMP candidates in 225 live days of XENON100 data in events with small S2 signals (with or without an accompanying S1) and which pass other simple selection cuts optimized for GeV-scale WIMPs. This rate is then used to set a limit on the WIMP-nucleon cross-section for the mass range 1-10 GeV.

  19. Dark matter in the solar system II: WIMP annihilation rates in the Sun

    E-print Network

    Annika H. G. Peter

    2009-02-09

    We calculate the annihilation rate of weakly interacting massive particles (WIMPs) in the Sun as a function of their mass and elastic scattering cross section. One byproduct of the annihilation, muon neutrinos, may be observed by the next generation of neutrino telescopes. Previous estimates of the annihilation rate assumed that any WIMPs from the Galactic dark halo that are captured in the Sun by elastic scattering off solar nuclei quickly reach thermal equilibrium in the Sun. We show that the optical depth of the Sun to WIMPs and the gravitational forces from planets both serve to decrease the annihilation rate below these estimates. While we find that the sensitivity of upcoming km^3-scale neutrino telescopes to ~100 GeV WIMPs is virtually unchanged from previous estimates, the sensitivity of these experiments to ~10 TeV WIMPs may be an order of magnitude less than the standard calculations would suggest. The new estimates of the annihilation rates should guide future experiment design and improve the mapping from neutrino event rates to WIMP parameter space.

  20. Radio constraints on Galactic WIMP dark matter

    E-print Network

    Roberto A. Lineros

    2013-09-18

    Synchrotron emission from electron cosmic ray populations can be used to study both cosmic rays physics and WIMP dark matter imprints on radio skymaps. We used available radio data - from MHz to GHz - to analyze the contribution from galactic WIMP annihilations and impose constraints on WIMP observables: annihilation cross section, channel and mass. Depending on the annihilation channel we obtain as competitive bounds as those obtained in FERMI-LAT gamma ray analysis of dwarf satellite galaxies.

  1. A comparison of heat and radiation sensitivity of three human glioma cell lines

    SciTech Connect

    Raaphorst, G.P.; Feeley, M.M.; Da Silva, V.F.; Danjoux, C.E.; Gerig, L.H. )

    1989-09-01

    Three human glioma cell lines were tested for radiation and hyperthermia sensitivity and compared to the responses of a normal human fibroblast cell line. The radiation response of the glioma cell lines exhibited a large shoulder on the radiation survival curve indicating radioresistance when compared to the more radiosensitive fibroblast cell line. The hyperthermia response for the glioma cell lines was qualitatively similar to responses reported for other cell lines. When compared to normal human fibroblasts the glioma cells were found to be more sensitive to hyperthermia than the normal fibroblasts indicating hyperthermia may be a promising method or adjunct to radiotherapy in the treatment of resistant glioma cells or tumors. The results also show that both the radiation and thermal response is influenced by cell culture conditions and growth status. Two of the cell lines grown to confluency and treated in confluency showed an increased radiation resistance at low doses and the cell lines showed decreased resistance at high doses compared to cells plated to confluency. An increased thermal resistance, especially at the lower heating temperatures, was also observed for cells grown to confluency. Measurements of residual glucose in the culture medium at the time of irradiation was about the same for the two culture methods (55%-65%). Cell cycle analysis showed that the differences were not related to changes in cell cycle distribution.

  2. Towards Direct Detection of WIMPs with the Cryogenic Dark Matter Search

    SciTech Connect

    Figueroa-Feliciano, E.

    2010-02-10

    The Cryogenic Dark Matter Search (CDMS) is carrying out a direct detection search for Weakly Interacting Massive Particles (WIMPs), one of the favored candidates for dark matter. Our latest data has placed some of the most stringent limits on the WIMP-nucleon spin-independent cross section of 6.6x10{sup -44} cm{sup 2} for 60 GeV WIMPs at the 90% confidence level. This paper describes our experiment and our latest results; the status of SuperCDMS Soudan, a new experiment at the Soudan mine in Minnesota that will achieve a sensitivity of 5x10{sup -45} cm{sup 2} our plans for SuperCDMS SNOLAB, a 100 kg experiment with a projected sensitivity of 3x10{sup -46} cm{sup 2}; and GEODM, a ton-scale experiment at DUSEL with a projected sensitivity of 2x10{sup -47} cm{sup 2}.

  3. WIMP Annihilation and Cooling of Neutron Stars

    E-print Network

    Chris Kouvaris

    2007-08-17

    We study the effect of WIMP annihilation on the temperature of a neutron star. We shall argue that the released energy due to WIMP annihilation inside the neutron stars, might affect the temperature of stars older than 10 million years, flattening out the temperature at $\\sim 10^4$ K for a typical neutron star.

  4. WIMP astronomy and particle physics with liquid-noble and cryogenic direct-detection experiments

    E-print Network

    Annika H. G. Peter

    2012-01-18

    Once weakly-interacting massive particles (WIMPs) are unambiguously detected in direct-detection experiments, the challenge will be to determine what one may infer from the data. Here, I examine the prospects for reconstructing the local speed distribution of WIMPs in addition to WIMP particle-physics properties (mass, cross sections) from next-generation cryogenic and liquid-noble direct-detection experiments. I find that the common method of fixing the form of the velocity distribution when estimating constraints on WIMP mass and cross sections means losing out on the information on the speed distribution contained in the data and may lead to biases in the inferred values of the particle-physics parameters. I show that using a more general, empirical form of the speed distribution can lead to good constraints on the speed distribution. Moreover, one can use Bayesian model-selection criteria to determine if a theoretically-inspired functional form for the speed distribution (such as a Maxwell-Boltzmann distribution) fits better than an empirical model. The shape of the degeneracy between WIMP mass and cross sections and their offset from the true values of those parameters depends on the hypothesis for the speed distribution, which has significant implications for consistency checks between direct-detection and collider data. In addition, I find that the uncertainties on theoretical parameters depends sensitively on the upper end of the energy range used for WIMP searches. Better constraints on the WIMP particle-physics parameters and speed distribution are obtained if the WIMP search is extended to higher energy (~ 1 MeV).

  5. Galactic Halos are Einstein Clusters of WIMPs

    E-print Network

    Kayll Lake

    2006-07-24

    It is shown that an Einstein cluster of WIMPs, WIMPs on stable circular geodesic orbits generating the static spherically symmetric gravitational field of a galactic halo, can exactly reproduce the rotation curve of any galaxy simply by adjusting the local angular momentum distribution and consequent number distribution of the WIMPs. No new physics is involved (assuming the forthcoming discovery of WIMPs). Further, stability of the orbits can require an inner truncation of the halo and an explicit example of this is given. There is no exact Newtonian counterpart to the model presented since pure Newtonian gravity fails to account for the contribution made by the angular momentum distribution of the particles in creating the gravitational field. In effect, a galactic halo is supported by the hoop stresses created by the orbiting WIMPs.

  6. 3-Bromopyruvate induces necrotic cell death in sensitive melanoma cell lines

    SciTech Connect

    Qin, J.-Z.; Xin, H.; Nickoloff, B.J.

    2010-05-28

    Clinicians successfully utilize high uptake of radiolabeled glucose via PET scanning to localize metastases in melanoma patients. To take advantage of this altered metabolome, 3-bromopyruvate (BrPA) was used to overcome the notorious resistance of melanoma to cell death. Using four melanoma cell lines, BrPA triggered caspase independent necrosis in two lines, whilst the other two lines were resistant to killing. Mechanistically, sensitive cells differed from resistant cells by; constitutively lower levels of glutathione, reduction of glutathione by BrPA only in sensitive cells; increased superoxide anion reactive oxygen species, loss of outer mitochondrial membrane permeability, and rapid ATP depletion. Sensitive cell killing was blocked by N-acetylcysteine or glutathione. When glutathione levels were reduced in resistant cell lines, they became sensitive to killing by BrPA. Taken together, these results identify a metabolic-based Achilles' heel in melanoma cells to be exploited by use of BrPA. Future pre-clinical and clinical trials are warranted to translate these results into improved patient care for individuals suffering from metastatic melanoma.

  7. The Cancer Cell Line Encyclopedia enables predictive modelling of anticancer drug sensitivity.

    PubMed

    Barretina, Jordi; Caponigro, Giordano; Stransky, Nicolas; Venkatesan, Kavitha; Margolin, Adam A; Kim, Sungjoon; Wilson, Christopher J; Lehár, Joseph; Kryukov, Gregory V; Sonkin, Dmitriy; Reddy, Anupama; Liu, Manway; Murray, Lauren; Berger, Michael F; Monahan, John E; Morais, Paula; Meltzer, Jodi; Korejwa, Adam; Jané-Valbuena, Judit; Mapa, Felipa A; Thibault, Joseph; Bric-Furlong, Eva; Raman, Pichai; Shipway, Aaron; Engels, Ingo H; Cheng, Jill; Yu, Guoying K; Yu, Jianjun; Aspesi, Peter; de Silva, Melanie; Jagtap, Kalpana; Jones, Michael D; Wang, Li; Hatton, Charles; Palescandolo, Emanuele; Gupta, Supriya; Mahan, Scott; Sougnez, Carrie; Onofrio, Robert C; Liefeld, Ted; MacConaill, Laura; Winckler, Wendy; Reich, Michael; Li, Nanxin; Mesirov, Jill P; Gabriel, Stacey B; Getz, Gad; Ardlie, Kristin; Chan, Vivien; Myer, Vic E; Weber, Barbara L; Porter, Jeff; Warmuth, Markus; Finan, Peter; Harris, Jennifer L; Meyerson, Matthew; Golub, Todd R; Morrissey, Michael P; Sellers, William R; Schlegel, Robert; Garraway, Levi A

    2012-03-29

    The systematic translation of cancer genomic data into knowledge of tumour biology and therapeutic possibilities remains challenging. Such efforts should be greatly aided by robust preclinical model systems that reflect the genomic diversity of human cancers and for which detailed genetic and pharmacological annotation is available. Here we describe the Cancer Cell Line Encyclopedia (CCLE): a compilation of gene expression, chromosomal copy number and massively parallel sequencing data from 947 human cancer cell lines. When coupled with pharmacological profiles for 24 anticancer drugs across 479 of the cell lines, this collection allowed identification of genetic, lineage, and gene-expression-based predictors of drug sensitivity. In addition to known predictors, we found that plasma cell lineage correlated with sensitivity to IGF1 receptor inhibitors; AHR expression was associated with MEK inhibitor efficacy in NRAS-mutant lines; and SLFN11 expression predicted sensitivity to topoisomerase inhibitors. Together, our results indicate that large, annotated cell-line collections may help to enable preclinical stratification schemata for anticancer agents. The generation of genetic predictions of drug response in the preclinical setting and their incorporation into cancer clinical trial design could speed the emergence of 'personalized' therapeutic regimens. PMID:22460905

  8. Proceedings of the 4th Patras Workshop on Axions, WIMPs

    E-print Network

    Proceedings of the 4th Patras Workshop on Axions, WIMPs and WISPs June 18-21, 2008 Hamburg, Germany;Impressum Proceedings of the 4th Patras Workshop on Axions, WIMPs and WISPs June 18-21, 2008, Hamburg, Germany Conference homepage http://axion-wimp2008.desy.de/ Slides at http://axion-wimp2008.desy.de/e30

  9. Drug-Resistant Urothelial Cancer Cell Lines Display Diverse Sensitivity Profiles to Potential Second-Line Therapeutics12

    PubMed Central

    Vallo, Stefan; Michaelis, Martin; Rothweiler, Florian; Bartsch, Georg; Gust, Kilian M.; Limbart, Dominik M.; Rödel, Franz; Wezel, Felix; Haferkamp, Axel; Cinatl, Jindrich

    2015-01-01

    Combination chemotherapy with gemcitabine and cisplatin in patients with metastatic urothelial cancer of the bladder frequently results in the development of acquired drug resistance. Availability of cell culture models with acquired resistance could help to identify candidate treatments for an efficient second-line therapy. Six cisplatin- and six gemcitabine-resistant cell lines were established. Cell viability assays were performed to evaluate the sensitivity to 16 different chemotherapeutic substances. The activity of the drug transporter ATP-binding cassette transporter, subfamily B, member 1 (ABCB1, a critical mediator of multidrug resistance in cancer) was evaluated using fluorescent ABCB1 substrates. For functional assessment, cells overexpressing ABCB1 were generated by transduction with a lentiviral vector encoding for ABCB1, while zosuquidar was used for selective inhibition. In this study, 8 of 12 gemcitabine- or cisplatin-resistant cell lines were cross-resistant to carboplatin, 5 to pemetrexed, 4 to methotrexate, 3 to oxaliplatin, 5-fluorouracil, and paclitaxel, and 2 to cabazitaxel, larotaxel, docetaxel, topotecan, doxorubicin, and mitomycin c, and 1 of 12 cell lines was cross-resistant to vinflunine and vinblastine. In one cell line with acquired resistance to gemcitabine (TCC-SUPrGEMCI20), cross-resistance seemed to be mediated by ABCB1 expression. Our model identified the vinca alkaloids vinblastine and vinflunine, in Europe an already approved second-line therapeutic for metastatic bladder cancer, as the most effective compounds in urothelial cancer cells with acquired resistance to gemcitabine or cisplatin. These results demonstrate that this in vitro model can reproduce clinically relevant results and may be suitable to identify novel substances for the treatment of metastatic bladder cancer. PMID:26055179

  10. WIMPs at the galactic center

    NASA Astrophysics Data System (ADS)

    Agrawal, Prateek; Batell, Brian; Fox, Patrick J.; Harnik, Roni

    2015-05-01

    Simple models of weakly interacting massive particles (WIMPs) predict dark matter annihilations into pairs of electroweak gauge bosons, Higgses or tops, which through their subsequent cascade decays produce a spectrum of gamma rays. Intriguingly, an excess in gamma rays coming from near the Galactic center has been consistently observed in Fermi data. A recent analysis by the Fermi collaboration confirms these earlier results. Taking into account the systematic uncertainties in the modelling of the gamma ray backgrounds, we show for the first time that this excess can be well fit by these final states. In particular, for annihilations to (WW, ZZ, hh, tbar t), dark matter with mass between threshold and approximately (165, 190, 280, 310) GeV gives an acceptable fit. The fit range for bbar b is also enlarged to 35 GeV lesssim m? lesssim 165 GeV. These are to be compared to previous fits that concluded only much lighter dark matter annihilating into b, ?, and light quark final states could describe the excess. We demonstrate that simple, well-motivated models of WIMP dark matter including a thermal-relic neutralino of the MSSM, Higgs portal models, as well as other simplified models can explain the excess.

  11. WIMPs at the galactic center

    SciTech Connect

    Agrawal, Prateek; Batell, Brian; Fox, Patrick J.; Harnik, Roni

    2015-05-01

    Simple models of weakly interacting massive particles (WIMPs) predict dark matter annihilations into pairs of electroweak gauge bosons, Higgses or tops, which through their subsequent cascade decays produce a spectrum of gamma rays. Intriguingly, an excess in gamma rays coming from near the Galactic center has been consistently observed in Fermi data. A recent analysis by the Fermi collaboration confirms these earlier results. Taking into account the systematic uncertainties in the modelling of the gamma ray backgrounds, we show for the first time that this excess can be well fit by these final states. In particular, for annihilations to (WW, ZZ, hh, tt¯), dark matter with mass between threshold and approximately (165, 190, 280, 310) GeV gives an acceptable fit. The fit range for bb¯ is also enlarged to 35 GeV ? m? ? 165 GeV. These are to be compared to previous fits that concluded only much lighter dark matter annihilating into b, ?, and light quark final states could describe the excess. We demonstrate that simple, well-motivated models of WIMP dark matter including a thermal-relic neutralino of the MSSM, Higgs portal models, as well as other simplified models can explain the excess.

  12. WIMPs at the galactic center

    DOE PAGESBeta

    Agrawal, Prateek; Batell, Brian; Fox, Patrick J.; Harnik, Roni

    2015-05-01

    Simple models of weakly interacting massive particles (WIMPs) predict dark matter annihilations into pairs of electroweak gauge bosons, Higgses or tops, which through their subsequent cascade decays produce a spectrum of gamma rays. Intriguingly, an excess in gamma rays coming from near the Galactic center has been consistently observed in Fermi data. A recent analysis by the Fermi collaboration confirms these earlier results. Taking into account the systematic uncertainties in the modelling of the gamma ray backgrounds, we show for the first time that this excess can be well fit by these final states. In particular, for annihilations to (WW,more »ZZ, hh, tt¯), dark matter with mass between threshold and approximately (165, 190, 280, 310) GeV gives an acceptable fit. The fit range for bb¯ is also enlarged to 35 GeV ? m? ? 165 GeV. These are to be compared to previous fits that concluded only much lighter dark matter annihilating into b, ?, and light quark final states could describe the excess. We demonstrate that simple, well-motivated models of WIMP dark matter including a thermal-relic neutralino of the MSSM, Higgs portal models, as well as other simplified models can explain the excess.« less

  13. Improved WIMP scattering limits from the LUX experiment

    E-print Network

    Akerib, D S; Bai, X; Bailey, A J; Balajthy, J; Beltrame, P; Bernard, E P; Bernstein, A; Biesiadzinski, T P; Boulton, E M; Bradley, A; Bramante, R; Cahn, S B; Carmona-Benitez, M C; Chan, C; Chapman, J J; Chiller, A A; Chiller, C; Currie, A; Cutter, J E; Davison, T J R; de Viveiros, L; Dobi, A; Dobson, J E Y; Druszkiewicz, E; Edwards, B N; Faham, C H; Fiorucci, S; Gaitskell, R J; Gehman, V M; Ghag, C; Gibson, K R; Gilchriese, M G D; Hall, C R; Hanhardt, M; Haselschwardt, S J; Hertel, S A; Hogan, D P; Horn, M; Huang, D Q; Ignarra, C M; Ihm, M; Jacobsen, R G; Ji, W; Kazkaz, K; Khaitan, D; Knoche, R; Larsen, N A; Lee, C; Lenardo, B G; Lesko, K T; Lindote, A; Lopes, M I; Malling, D C; Manalaysay, A; Mannino, R L; Marzioni, M F; McKinsey, D N; Mei, D M; Mock, J; Moongweluwan, M; Morad, J A; Murphy, A St J; Nehrkorn, C; Nelson, H N; Neves, F; O`Sullivan, K; Oliver-Mallory, K C; Ott, R A; Palladino, K J; Pangilinan, M; Pease, E K; Phelps, P; Reichhart, L; Rhyne, C; Shaw, S; Shutt, T A; Silva, C; Solovov, V N; Sorensen, P; Stephenson, S; Sumner, T J; Szydagis, M; Taylor, D J; Taylor, W; Tennyson, B P; Terman, P A; Tiedt, D R; To, W H; Tripathi, M; Tvrznikova, L; Uvarov, S; Verbus, J R; Webb, R C; White, J T; Whitis, T J; Witherell, M S; Wolfs, F L H; Yazdani, K; Young, S K; Zhang, C

    2015-01-01

    We present constraints on WIMP-nucleus scattering from the 2013 data of the Large Underground Xenon (LUX) dark matter experiment, including $1.4\\times10^{4}\\,\\mathrm{kg\\cdot days}$ of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength; improved event-reconstruction algorithms; a revised background model including events originating on the detector walls in an enlarged fiducial volume; and new calibrations from decays of an injected tritium $\\beta$ source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4 $\\mathrm{GeV}\\,c^{-2}$, these new results give the most stringent direct limits on the spin-independent WIMP-nucleon cross section. The 90% CL upper limit has a minimum of 0.4 zb at 33 $\\mathrm{GeV}\\,c^...

  14. Improved Spin-Dependent WIMP Limits from a Bubble Chamber

    E-print Network

    E. Behnke; J. I. Collar; P. S. Cooper; K. Crum; M. Crisler; M. Hu; I. Levine; D. Nakazawa; H. Nguyen; B. Odom; E. Ramberg; J. Rasmussen; N. Riley; A. Sonnenschein; M. Szydagis; R. Tschirhart

    2008-04-17

    Bubble Chambers provided the dominant particle detection technology in accelerator experiments for several decades, eventually falling into disuse with the advent of other techniques. We report here on the first period of operation of an ultra-clean, room-temperature bubble chamber containing 1.5 kg of superheated CF$_{3}$I, a target maximally sensitive to spin-dependent and -independent Weakly Interacting Massive Particle (WIMP) couplings. An exposure in excess of 250 kg-days is obtained, with a live-time fraction reaching 80%. This illustrates the ability to employ bubble chambers in a new realm, the search for dark matter particles. Improved limits on the spin-dependent WIMP-proton scattering cross section are extracted from this first period. An extreme intrinsic insensitivity to the backgrounds commonly limiting these experiments (a rejection factor for photon-induced electrons of $\\sim10^{-10}$) has been measured in operating conditions leading to the detection of low-energy nuclear recoils such as those expected from WIMPs.

  15. Soft collinear effective theory for heavy WIMP annihilation

    NASA Astrophysics Data System (ADS)

    Bauer, Martin; Cohen, Timothy; Hill, Richard J.; Solon, Mikhail P.

    2015-01-01

    In a large class of models for Weakly Interacting Massive Particles (WIMPs), the WIMP mass M lies far above the weak scale m W . This work identifies universal Sudakov-type logarithms ˜ ? log2(2 M/m W ) that spoil the naive convergence of perturbation theory for annihilation processes. An effective field theory (EFT) framework is presented, allowing the systematic resummation of these logarithms. Another impact of the large separation of scales is that a long-distance wavefunction distortion from electroweak boson exchange leads to observable modifications of the cross section. Careful accounting of momentum regions in the EFT allows the rigorous disentanglement of this so-called Sommerfeld enhancement from the short-distance hard annihilation process. The WIMP is described as a heavy-particle field, while the electroweak gauge bosons are treated as soft and collinear fields. Hard matching coefficients are computed at renormalization scale ? ˜ 2 M , then evolved down to ? ˜ m W , where electroweak symmetry breaking is incorporated and the matching onto the relevant quantum mechanical Hamiltonian is performed. The example of an SU(2) W triplet scalar dark matter candidate annihilating to line photons is used for concreteness, allowing the numerical exploration of the impact of next-to-leading order corrections and log resummation. For M ? 3 TeV, the resummed Sommerfeld enhanced cross section is reduced by a factor of ˜ 3 with respect to the treelevel fixed order result.

  16. Soft collinear effective theory for heavy WIMP annihilation

    DOE PAGESBeta

    Bauer, Martin; Cohen, Timothy; Hill, Richard J.; Solon, Mikhail P.

    2015-01-19

    In a large class of models for Weakly Interacting Massive Particles (WIMPs), the WIMP mass M lies far above the weak scale mW. This work identifies universal Sudakov-type logarithms ~ ? log²(2 M / mW) that spoil the naive convergence of perturbation theory for annihilation processes. An effective field theory (EFT) framework is presented, allowing the systematic resummation of these logarithms. Another impact of the large separation of scales is that a long-distance wavefunction distortion from electroweak boson exchange leads to observable modifications of the cross section. Careful accounting of momentum regions in the EFT allows the rigorous disentanglement ofmore »this so-called Sommerfeld enhancement from the short-distance hard annihilation process. The WIMP is described as a heavy-particle field, while the electroweak gauge bosons are treated as soft and collinear fields. Hard matching coefficients are computed at renormalization scale ? ~ 2 M , then evolved down to ? ~ mW, where electroweak symmetry breaking is incorporated and the matching onto the relevant quantum mechanical Hamiltonian is performed. The example of an SU(2)W triplet scalar dark matter candidate annihilating to line photons is used for concreteness, allowing the numerical exploration of the impact of next-to-leading order corrections and log resummation. For M ? 3 TeV, the resummed Sommerfeld enhanced cross section is reduced by a factor of ~ 3 with respect to the treelevel fixed order result.« less

  17. Soft collinear effective theory for heavy WIMP annihilation

    SciTech Connect

    Bauer, Martin; Cohen, Timothy; Hill, Richard J.; Solon, Mikhail P.

    2015-01-19

    In a large class of models for Weakly Interacting Massive Particles (WIMPs), the WIMP mass M lies far above the weak scale mW. This work identifies universal Sudakov-type logarithms ~ ? log²(2 M / mW) that spoil the naive convergence of perturbation theory for annihilation processes. An effective field theory (EFT) framework is presented, allowing the systematic resummation of these logarithms. Another impact of the large separation of scales is that a long-distance wavefunction distortion from electroweak boson exchange leads to observable modifications of the cross section. Careful accounting of momentum regions in the EFT allows the rigorous disentanglement of this so-called Sommerfeld enhancement from the short-distance hard annihilation process. The WIMP is described as a heavy-particle field, while the electroweak gauge bosons are treated as soft and collinear fields. Hard matching coefficients are computed at renormalization scale ? ~ 2 M , then evolved down to ? ~ mW, where electroweak symmetry breaking is incorporated and the matching onto the relevant quantum mechanical Hamiltonian is performed. The example of an SU(2)W triplet scalar dark matter candidate annihilating to line photons is used for concreteness, allowing the numerical exploration of the impact of next-to-leading order corrections and log resummation. For M ? 3 TeV, the resummed Sommerfeld enhanced cross section is reduced by a factor of ~ 3 with respect to the treelevel fixed order result.

  18. Determining the WIMP mass from a single direct detection experiment

    E-print Network

    Anne M Green

    2008-09-11

    The energy spectrum of nuclear recoils in Weakly Interacting Massive Particle (WIMP) direct detection experiments depends on the underlying WIMP mass (strongly for light WIMPs, weakly for heavy WIMPs). We discuss how the accuracy with which the WIMP mass could be determined by a single direct detection experiment depends on the detector configuration and the WIMP properties. In particular we examine the effects of varying the underlying WIMP mass, the detector target nucleus, exposure, energy threshold and maximum energy, the local velocity distribution and the background event rate and spectrum.

  19. Sensitivity of gastric adenocarcinoma and normal cell lines against combined or conjugated antimetabolites.

    PubMed

    Weinreich, Jürgen; Struller, Florian; Küper, Markus; Hack, Anita; Königsrainer, Alfred; Schott, Timm C

    2013-04-01

    The in-vitro growth inhibition of cancer and normal cell lines caused by mixed or covalently linked antimetabolites should clarify whether the conjugation of antimetabolites influences cell sensitivity and growth inhibition in a manner that differs from an equimolar mixture of the same antimetabolites or not. Growth inhibition of the human gastric adenocarcinoma cell lines 23132/87 and MKN-45 in comparison with normal gastric intestinal CCL-241 and the dermal fibroblast cell line NHDF was evaluated using CASY technology. The cell lines were incubated with an equimolar mixture of 5-fluoro-2'-deoxyuridine (5FdU)+3'-C-ethynylcytidine (ECyd) or the covalently linked duplex drug 5FdU(5'?5')ECyd. The drug and metabolites of the assays and medium were determined semiquantitatively using high-performance liquid chromatography. The sensitivity of cancer and nonmalignant cell lines was clearly different against the duplex drug. A measure of 0.65 µmol/l 5FdU(5'?5')ECyd, for example, reduced the growth of MKN-45 or 23132/87 gastric cancer cells from 100% on day 0 to about 50 or 20% on day 10, respectively. However, under the same conditions, the growth of the nonmalignant NHDF and CCL-241 cell lines was not markedly inhibited. The cytostatic activity of the duplex drug is based on the active metabolites in and outside the cell formed by the degradation of 5FdU(5'?5')ECyd. The sensitivity of cell lines against the duplex drug depended on its ability to metabolize the duplex drug. 5FdU(5'?5')ECyd should be more advantageous for specific and efficient polychemotherapy of gastric cancer than the corresponding equimolar mixture of 5FdU+ECyd or a standard combination regime of single drugs. PMID:23358120

  20. Model-independent WIMP Characterisation using ISR

    E-print Network

    Christoph Bartels; Olaf Kittel; Ulrich Langenfeld; Jenny List

    2012-03-01

    The prospects of measuring the parameters of WIMP dark matter in a model independent way at the International Linear Collider are investigated. The signal under study is direct WIMP pair production with associated initial state radiation. The analysis is performed in full simulation of the ILD detector concept. With an integrated luminosity of L = 500 fb-1 and realistic beam polarizations the helicity structure of the WIMP couplings to electrons can be determined, and the masses and cross sections can be measured to the percent level. The systematic uncertainties are dominated by the polarization measurement and the luminosity spectrum.

  1. A review of WIMP baryogenesis mechanisms

    NASA Astrophysics Data System (ADS)

    Cui, Yanou

    2015-12-01

    It was recently proposed that weakly interacting massive particles (WIMP) may provide new ways of generating the observed baryon asymmetry in the early universe, as well as addressing the cosmic coincidence between dark matter (DM) and baryon abundances. This suggests a new possible connection between weak scale new particle physics and modern cosmology. This review summarizes the general ideas and simple model examples of the two recently proposed WIMP baryogenesis mechanisms: baryogenesis from WIMP DM annihilation during thermal freeze-out, and baryogenesis from metastable WIMP decay after thermal freeze-out. This review also discusses the interesting phenomenology of these models, in particular, the experimental signals that can be probed in the intensity frontier experiments and the large hadron collider (LHC) experiments.

  2. A Review of WIMP Baryogenesis Mechanisms

    E-print Network

    Cui, Yanou

    2015-01-01

    It was recently proposed that weakly interacting massive particles (WIMP) may provide new ways of generating the observed baryon asymmetry in the early universe, as well as addressing the cosmic coincidence between dark matter and baryon abundances. This suggests a new possible connection between weak scale new particle physics and modern cosmology. This review summarizes the general ideas and simple model examples of the two recently proposed WIMP baryogenesis mechanisms: baryogenesis from WIMP dark matter annihilation during thermal freezeout, and baryogenesis from metastable WIMP decay after thermal freezeout. This letter also discusses the interesting phenomenology of these models, in particular the experimental signals that can be probed in the intensity frontier experiments and the Large Hadron Collider (LHC) experiments.

  3. Spin-dependent WIMP scattering off nuclei

    E-print Network

    J. Menendez; D. Gazit; A. Schwenk

    2012-11-09

    Chiral effective field theory (EFT) provides a systematic expansion for the coupling of WIMPs to nucleons at the momentum transfers relevant to direct cold dark matter detection. We derive the currents for spin-dependent WIMP scattering off nuclei at the one-body level and include the leading long-range two-body currents, which are predicted in chiral EFT. As an application, we calculate the structure factor for spin-dependent WIMP scattering off 129,131Xe nuclei, using nuclear interactions that have been developed to study nuclear structure and double-beta decays in this region. We provide theoretical error bands due to the nuclear uncertainties of WIMP currents in nuclei.

  4. A Review of WIMP Baryogenesis Mechanisms

    E-print Network

    Yanou Cui

    2015-10-14

    It was recently proposed that weakly interacting massive particles (WIMP) may provide new ways of generating the observed baryon asymmetry in the early universe, as well as addressing the cosmic coincidence between dark matter and baryon abundances. This suggests a new possible connection between weak scale new particle physics and modern cosmology. This review summarizes the general ideas and simple model examples of the two recently proposed WIMP baryogenesis mechanisms: baryogenesis from WIMP dark matter annihilation during thermal freezeout, and baryogenesis from metastable WIMP decay after thermal freezeout. This letter also discusses the interesting phenomenology of these models, in particular the experimental signals that can be probed in the intensity frontier experiments and the Large Hadron Collider (LHC) experiments.

  5. Spin-dependent WIMP scattering off nuclei

    E-print Network

    Menendez, J; Schwenk, A

    2012-01-01

    Chiral effective field theory (EFT) provides a systematic expansion for the coupling of WIMPs to nucleons at the momentum transfers relevant to direct cold dark matter detection. We derive the currents for spin-dependent WIMP scattering off nuclei at the one-body level and include the leading long-range two-body currents, which are predicted in chiral EFT. As an application, we calculate the structure factor for spin-dependent WIMP scattering off 129,131Xe nuclei, using nuclear interactions that have been developed to study nuclear structure and double-beta decays in this region. We provide theoretical error bands due to the nuclear uncertainties of WIMP currents in nuclei.

  6. Isolation and preliminary characterization of u. v. -sensitive mutants from the human cell line EUE

    SciTech Connect

    Fiorio, R.; Frosina, G.; Abbondandolo, A.

    1983-01-01

    Five u.v. light-sensitive clones were isolated in the EUE cell line by means of a modified form of the original 5-bromodeoxyuridine (BUdR)-light method worked out by Puck and Kao for the isolation of nutritional mutants. A cell population was mutagenized with ethylmethanesulfonate. After the expression time, cells were u.v.-irradiated and incubated with BUdR to label excision patches in repair proficient cells. A subsequent irradiation with black light caused DNA strand breakage in BUdR-substituted cells. During BUdR treatment, hydroxyurea and a fluorochrome (Hoechst 33258) were added to possibly enhance the analogue incorporation into DNA and to increase the photolability of BUdR containing sequences, respectively. Out of 192 colonies selected with this method, 38 were isolated and tested for their u.v.-sensitivity. Five of them showed significant, reproducible differences with respect to the parental line. As a partial characterization, the five u.v.-sensitive clones were assayed for unscheduled (/sup 3/H)thymidine incorporation after exposure to u.v. light, by means of liquid scintillation spectrometry and autoradiography. In all clones. DNA repair synthesis was significantly decreased with respect to the parental line.

  7. [Establishment and characterization of human ovarian fibrosarcoma cell line and its sensitivity to anticancer agents].

    PubMed

    Kiyozuka, Y; Nishimura, H; Iwanaga, S; Yakushiji, M; Ito, K; Nakano, S; Tamori, N; Adachi, S; Noda, T; Imai, S

    1992-04-01

    We succeeded in establishing a cell line (KEN-3) for subculture from a fibrosarcoma which originated in the ovary in a girl aged 17 years. Its characteristics and sensitivity to anticancer agents are reported in this paper. 1. Characteristics of established cell line. Lined cells consist of multinucleated giant cells mixed among many spindle-shaped cells. They grow in small colonies and have none of the pavement-like arrangement characteristic of epithelial tumor cells. The number of chromosomes ranged from 45 to 128 (mode: pseudo-triploidy region, 65). The doubling time, cellular density and plating efficiency were 76.9 hours, 5.4 x 10(5)/cm2 and 30.2%, respectively. Concerning tumor markers, CEA and sialyl SSEA-1 were only produced in small quantities. Subculture was possible subcutaneously in the nude mouse with no capacity for the production of ascites. 2. Susceptibility to anticancer agents and GP170 expression. The in vitro susceptibility to about 12 types of anticancer agents was investigated with the MTT assay. IC50/PPC was shown to be less than 1 for Adriamycin only. The sensitivity to CDDP (IC50/PPC: 4.8) was low, and no sensitivity was observed at all to DTIC, which is used frequently for mesenchymal tumors. GP170 (mdr-1 products) was positive in established cells in immunohistochemical stain. PMID:1351514

  8. WIMP abundance and lepton (flavour) asymmetry

    SciTech Connect

    Stuke, Maik; Schwarz, Dominik J.; Starkman, Glenn E-mail: dschwarz@physik.uni-bielefeld.de

    2012-03-01

    We investigate how large lepton asymmetries affect the evolution of the early universe at times before big bang nucleosynthesis and in particular how they influence the relic density of WIMP dark matter. In comparison to the standard calculation of the relic WIMP abundance we find a decrease, depending on the lepton flavour asymmetry. We find an effect of up to 20 per cent for lepton flavour asymmetries l{sub f} = O(0.1)

  9. Predicted rates for direct WIMP searches

    E-print Network

    J. D. Vergados

    2012-01-26

    The differential event rate for direct detection of dark matter, both the time averaged and the modulated one due to the motion of the Earth, are discussed. The calculations focus on relatively light cold dark matter candidates (WIMP) and low energy transfers. It is shown that for some WIMP masses the modulation amplitude may change sign. This effect can be exploited to yield information about the mass of the dark matter candidate.

  10. Solar WIMPs Unraveled: Experiments, astrophysical uncertainties, and interactive Tools

    E-print Network

    Danninger, Matthias

    2015-01-01

    The absence of a neutrino flux from self-annihilating dark matter captured in the Sun has tightly constrained some leading particle dark matter scenarios. The impact of astrophysical uncertainties on the capture process of dark matter in the Sun and hence also the derived constraints by neutrino telescopes need to be taken into account. In this review we have explored relevant uncertainties in solar WIMP searches, summarized results from leading experiments, and provided an outlook into upcoming searches and future experiments. We have created an interactive plotting tool that allows the user to view current limits and projected sensitivities of major experiments under changing astrophysical conditions.

  11. Comparative sensitivity of four different cell lines for the isolation of Coxiella burnetii.

    PubMed

    Lockhart, Michelle G; Islam, Aminul; Fenwick, Stan G; Graves, Stephen R; Stenos, John

    2012-09-01

    Coxiella burnetii is an obligate intracellular bacterium that causes the disease Q-fever. This is usually diagnosed by serology (immunofluorescence assay) and/or PCR detection of C. burnetii DNA. However, neither of these methods can determine the viability of the bacterium. Four different cell lines were compared for their ability to amplify very low numbers of viable C. burnetii. Two different isolates of C. burnetii were used. For the Henzerling isolate, DH82 (dog macrophage) cells were the most sensitive with an ID (50) (dose required to infect 50% of cell cultures) of 14.6 bacterial copies. For the Arandale isolate, Vero (monkey epithelial) cells were the most sensitive with an ID (50) of less than one bacterium in a 100-?L inoculum. The Vero cell line appeared highly useful as vacuoles could be seen microscopically in unstained infected cells. The findings of this study favour the use of Vero and DH82 tissue culture cell lines for isolation and growth of C. burnetii in vitro. The other cell lines, XTC-2 and L929, were less suitable. PMID:22681323

  12. Low-Background Detector Development at EFI: WIMPs, Axions, Neutrinos, and Other Sneaky Beasts

    SciTech Connect

    Collar, Juan

    2003-12-03

    I will review the status of several experimental efforts at University of Chicago aiming at the detection of astrophysical exotica: a bubble chamber using CF3I and CF3Br dedicated to WIMP searches, the CAST experiment at CERN (looking for solar axions) and R&D towards a detector sensitive to very low-energy nuclear recoils from coherent neutrino scattering.

  13. Improved WIMP-search reach of the CDMS II germanium data

    SciTech Connect

    Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Bowles, M. A.; Brandt, D.; Brink, P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Calkins, R.; Cerdeno, D. G.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, Priscilla B.; Daal, M.; Di Stefano, P. C.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, Jeter C.; Harris, H. R.; Hertel, S. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D. M.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Kiveni, M.; Koch, K.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; Mandic, V.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Rogers, H. E.; Saab, T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.

    2015-10-31

    CDMS II data from the five-tower runs at the Soudan Underground Laboratory were reprocessed with an improved charge-pulse fitting algorithm. Two new analysis techniques to reject surface-event backgrounds were applied to the 612 kg days germanium-detector weakly interacting massive particle (WIMP)-search exposure. An extended analysis was also completed by decreasing the 10 keV analysis threshold to ~5 keV, to increase sensitivity near a WIMP mass of 8 GeV/c2. After unblinding, there were zero candidate events above a deposited energy of 10 keV and six events in the lower-threshold analysis. This yielded minimum WIMP-nucleon spin-independent scattering cross-section limits of 1.8×10-44 and 1.18×10-41 at 90% confidence for 60 and 8.6 GeV/c2 WIMPs, respectively. This improves the previous CDMS II result by a factor of 2.4 (2.7) for 60 (8.6) GeV/c2 WIMPs.

  14. Improved WIMP-search reach of the CDMS II germanium data

    E-print Network

    R. Agnese; A. J. Anderson; M. Asai; D. Balakishiyeva; D. Barker; R. Basu Thakur; D. A. Bauer; J. Billard; A. Borgland; M. A. Bowles; D. Brandt; P. L. Brink; R. Bunker; B. Cabrera; D. O. Caldwell; R. Calkins; D. G. Cerdeño; H. Chagani; Y. Chen; J. Cooley; B. Cornell; C. H. Crewdson; P. Cushman; M. Daal; P. C. F. Di Stefano; T. Doughty; L. Esteban; S. Fallows; E. Figueroa-Feliciano; G. L. Godfrey; S. R. Golwala; J. Hall; H. R. Harris; S. A. Hertel; T. Hofer; D. Holmgren; L. Hsu; M. E. Huber; D. Jardin; A. Jastram; O. Kamaev; B. Kara; M. H. Kelsey; A. Kennedy; M. Kiveni; K. Koch; A. Leder; B. Loer; E. Lopez Asamar; P. Lukens; R. Mahapatra; V. Mandic; K. A. McCarthy; N. Mirabolfathi; R. A. Moffatt; S. M. Oser; K. Page; W. A. Page; R. Partridge; M. Pepin; A. Phipps; K. Prasad; M. Pyle; H. Qiu; W. Rau; P. Redl; A. Reisetter; Y. Ricci; H. E. Rogers; T. Saab; B. Sadoulet; J. Sander; K. Schneck; R. W. Schnee; S. Scorza; B. Serfass; B. Shank; D. Speller; D. Toback; S. Upadhyayula; A. N. Villano; B. Welliver; J. S. Wilson; D. H. Wright; X. Yang; S. Yellin; J. J. Yen; B. A. Young; J. Zhang

    2015-10-13

    CDMS II data from the 5-tower runs at the Soudan Underground Laboratory were reprocessed with an improved charge-pulse fitting algorithm. Two new analysis techniques to reject surface-event backgrounds were applied to the 612 kg days germanium-detector WIMP-search exposure. An extended analysis was also completed by decreasing the 10 keV analysis threshold to $\\sim$5 keV, to increase sensitivity near a WIMP mass of 8 GeV/$c^2$. After unblinding, there were zero candidate events above a deposited energy of 10 keV and 6 events in the lower-threshold analysis. This yielded minimum WIMP-nucleon spin-independent scattering cross-section limits of $1.8 \\times 10^{-44}$ and $1.18 \\times 10 ^{-41}$ cm$^2$ at 90\\% confidence for 60 and 8.6 GeV/$c^2$ WIMPs, respectively. This improves the previous CDMS II result by a factor of 2.4 (2.7) for 60 (8.6) GeV/$c^2$ WIMPs.

  15. Improved WIMP-search reach of the CDMS II germanium data

    E-print Network

    Agnese, R; Asai, M; Balakishiyeva, D; Barker, D; Thakur, R Basu; Bauer, D A; Billard, J; Borgland, A; Bowles, M A; Brandt, D; Brink, P L; Bunker, R; Cabrera, B; Caldwell, D O; Calkins, R; Cerdeño, D G; Chagani, H; Chen, Y; Cooley, J; Cornell, B; Crewdson, C H; Cushman, P; Daal, M; Di Stefano, P C F; Doughty, T; Esteban, L; Fallows, S; Figueroa-Feliciano, E; Godfrey, G L; Golwala, S R; Hall, J; Harris, H R; Hertel, S A; Hofer, T; Holmgren, D; Hsu, L; Huber, M E; Jardin, D; Jastram, A; Kamaev, O; Kara, B; Kelsey, M H; Kennedy, A; Kiveni, M; Koch, K; Leder, A; Loer, B; Asamar, E Lopez; Lukens, P; Mahapatra, R; Mandic, V; McCarthy, K A; Mirabolfathi, N; Moffatt, R A; Oser, S M; Page, K; Page, W A; Partridge, R; Pepin, M; Phipps, A; Prasad, K; Pyle, M; Qiu, H; Rau, W; Redl, P; Reisetter, A; Ricci, Y; Rogers, H E; Saab, T; Sadoulet, B; Sander, J; Schneck, K; Schnee, R W; Scorza, S; Serfass, B; Shank, B; Speller, D; Toback, D; Upadhyayula, S; Villano, A N; Welliver, B; Wilson, J S; Wright, D H; Yang, X; Yellin, S; Yen, J J; Young, B A; Zhang, J

    2015-01-01

    CDMS II data from the 5-tower runs at the Soudan Underground Laboratory were reprocessed with an improved charge-pulse fitting algorithm. Two new analysis techniques to reject surface-event backgrounds were applied to the 612 kg days germanium-detector WIMP-search exposure. An extended analysis was also completed by decreasing the 10 keV analysis threshold to $\\sim$5 keV, to increase sensitivity near a WIMP mass of 8 GeV/$c^2$. After unblinding, there were zero candidate events above a deposited energy of 10 keV and 6 events in the lower-threshold analysis. This yielded minimum WIMP-nucleon spin-independent scattering cross-section limits of $1.8 \\times 10^{-44}$ and $1.18 \\times 10 ^{-41}$ cm$^2$ at 90\\% confidence for 60 and 8.6 GeV/$c^2$ WIMPs, respectively. This improves the previous CDMS II result by a factor of 2.4 (2.7) for 60 (8.6) GeV/$c^2$ WIMPs.

  16. Improved WIMP-search reach of the CDMS II germanium data

    NASA Astrophysics Data System (ADS)

    Agnese, R.; Anderson, A. J.; Asai, M.; Balakishiyeva, D.; Barker, D.; Basu Thakur, R.; Bauer, D. A.; Billard, J.; Borgland, A.; Bowles, M. A.; Brandt, D.; Brink, P. L.; Bunker, R.; Cabrera, B.; Caldwell, D. O.; Calkins, R.; Cerdeño, D. G.; Chagani, H.; Chen, Y.; Cooley, J.; Cornell, B.; Crewdson, C. H.; Cushman, P.; Daal, M.; Di Stefano, P. C. F.; Doughty, T.; Esteban, L.; Fallows, S.; Figueroa-Feliciano, E.; Godfrey, G. L.; Golwala, S. R.; Hall, J.; Harris, H. R.; Hertel, S. A.; Hofer, T.; Holmgren, D.; Hsu, L.; Huber, M. E.; Jardin, D.; Jastram, A.; Kamaev, O.; Kara, B.; Kelsey, M. H.; Kennedy, A.; Kiveni, M.; Koch, K.; Leder, A.; Loer, B.; Lopez Asamar, E.; Lukens, P.; Mahapatra, R.; Mandic, V.; McCarthy, K. A.; Mirabolfathi, N.; Moffatt, R. A.; Oser, S. M.; Page, K.; Page, W. A.; Partridge, R.; Pepin, M.; Phipps, A.; Prasad, K.; Pyle, M.; Qiu, H.; Rau, W.; Redl, P.; Reisetter, A.; Ricci, Y.; Rogers, H. E.; Saab, T.; Sadoulet, B.; Sander, J.; Schneck, K.; Schnee, R. W.; Scorza, S.; Serfass, B.; Shank, B.; Speller, D.; Toback, D.; Upadhyayula, S.; Villano, A. N.; Welliver, B.; Wilson, J. S.; Wright, D. H.; Yang, X.; Yellin, S.; Yen, J. J.; Young, B. A.; Zhang, J.; SuperCDMS Collaboration

    2015-10-01

    CDMS II data from the five-tower runs at the Soudan Underground Laboratory were reprocessed with an improved charge-pulse fitting algorithm. Two new analysis techniques to reject surface-event backgrounds were applied to the 612 kg days germanium-detector weakly interacting massive particle (WIMP)-search exposure. An extended analysis was also completed by decreasing the 10 keV analysis threshold to ˜5 keV , to increase sensitivity near a WIMP mass of 8 GeV /c2 . After unblinding, there were zero candidate events above a deposited energy of 10 keV and six events in the lower-threshold analysis. This yielded minimum WIMP-nucleon spin-independent scattering cross-section limits of 1.8 ×10-44 and 1.18 ×10-41 at 90% confidence for 60 and 8.6 GeV /c2 WIMPs, respectively. This improves the previous CDMS II result by a factor of 2.4 (2.7) for 60 (8.6 ) GeV /c2 WIMPs.

  17. Improving bioreactor cultivation conditions for sensitive cell lines by dynamic membrane aeration.

    PubMed

    Frahm, Björn; Brod, Helmut; Langer, Uwe

    2009-01-01

    Although the importance of animal cell culture for the industrial (large scale) production of pharmaceutical products is continuously increasing, the sensibility of the cells towards their cultivation environment is still a challenging issue. In comparison to microbial cultures, cell cultures which are not protected by a cell wall are much more sensitive to shear stress and foam formation. Reactor design as well as the selection of 'robust' cell lines is particularly important for these circumstances. Nevertheless, even 'sensitive' cell lines are selected for certain pharmaceutical processes due to various reasons. These sensitive cell lines have even higher requirements regarding their cultivation environment. Important characteristics for the corresponding reactor design are a high (volumetric) gas mass transfer coefficient, low volumetric power input, low shear stress, low susceptibility to bio-fouling, the ability to cultivate sticky cells and sufficient mixing properties. Membrane aeration has been a long-known possibility to meet some of these requirements, but has not often been applied in recent years. The reasons lie mainly in low gas mass transfer rates, a limited installable volume-specific membrane surface area, restrictions in scalability and problems with membrane fouling. The dynamic membrane aeration bioreactor aeration is a simple concept for bubble-free oxygen supply of such sensitive cultures. It overcomes limitations and draw-backs of previous systems. Consisting of an oscillating, centrally arranged rotor (stirrer) that is wrapped with silicone membrane tubing, it enables doubling the gas mass transfer at the same shear stress in the investigated cultivation scales of 12, 20, 100, and 200 L. Continuous cultivation at these scales allows the same product output as fed-batch cultivation does at tremendously larger reactor volumes. Apart from introducing this novel technology, the presentation comprises selected cultivation results obtained for blood coagulation factor VIII in continuous mode and a therapeutic monoclonal antibody in fed-batch mode in comparison to reference trials. PMID:19319654

  18. Simultaneous inhibition of ATR and PARP sensitizes colon cancer cell lines to irinotecan

    PubMed Central

    Abu-Sanad, Atlal; Wang, Yunzhe; Hasheminasab, Fatemeh; Panasci, Justin; Noë, Alycia; Rosca, Lorena; Davidson, David; Amrein, Lilian; Sharif-Askari, Bahram; Aloyz, Raquel; Panasci, Lawrence

    2015-01-01

    Enhanced DNA damage repair is one mechanism involved in colon cancer drug resistance. Thus, targeting molecular components of repair pathways with specific small molecule inhibitors may improve the efficacy of chemotherapy. ABT-888 and VE-821, inhibitors of poly-ADP-ribose-polymerase (PARP) and the serine/threonine-kinase Ataxia telangiectasia related (ATR), respectively, were used to treat colon cancer cell lines in combination with the topoisomerase-I inhibitor irinotecan (SN38). Our findings show that each of these DNA repair inhibitors utilized alone at nontoxic single agent concentrations resulted in sensitization to SN38 producing a 1.4–3 fold reduction in the 50% inhibitory concentration (IC50) of SN38 in three colon cancer cell lines. When combined together, nontoxic concentrations of ABT-888 and VE-821 produced a 4.5–27 fold reduction in the IC50 of SN38 with the HCT-116 colon cancer cells demonstrating the highest sensitization as compared to LoVo and HT-29 colon cancer cells. Furthermore, the combination of all three agents was associated with maximal G2 ?M arrest and enhanced DNA-damage (?H2AX) in all three colon cancer cell lines. The mechanism of this enhanced sensitization was associated with: (a) maximal suppression of SN38 induced PARP activity in the presence of both inhibitors and (b) ABT-888 producing partial abrogation of the VE-821 enhancement of SN38 induced DNA-PK phosphorylation, resulting in more unrepaired DNA damage; these alterations were only present in the HCT-116 cells which have reduced levels of ATM. This novel combination of DNA repair inhibitors may be useful to enhance the activity of DNA damaging chemotherapies such as irinotecan and help produce sensitization to this drug in colon cancer. PMID:26257651

  19. Determining the WIMP Mass from Direct Dark Matter Detection Data

    E-print Network

    Chung-Lin Shan; Manuel Drees

    2007-10-26

    Weakly interacting massive particles (WIMPs) are one of the leading candidates for Dark Matter. So far we can use direct Dark Matter detection to estimate the mass of halo WIMPs only by fitting predicted recoil spectra to future experimental data. Here we develop a model-independent method for determining the WIMP mass by using experimental data directly. This method is independent of the as yet unknown WIMP density near the Earth as well as of the WIMP-nuclear cross section and can be used to extract information about WIMP mass with O(50) events.

  20. Sensitivities of the equilibrium line altitude to temperature and precipitation changes along the Andes

    NASA Astrophysics Data System (ADS)

    Sagredo, Esteban A.; Rupper, Summer; Lowell, Thomas V.

    2014-03-01

    Equilibrium line altitudes (ELAs) of alpine glaciers are sensitive indicators of climate change and have been commonly used to reconstruct paleoclimates at different temporal and spatial scales. However, accurate interpretations of ELA fluctuations rely on a quantitative understanding of the sensitivity of ELAs to changes in climate. We applied a full surface energy- and mass-balance model to quantify ELA sensitivity to temperature and precipitation changes across the range of climate conditions found in the Andes. Model results show that ELA response has a strong spatial variability across the glaciated regions of South America. This spatial variability correlates with the distribution of the present-day mean climate conditions observed along the Andes. We find that ELAs respond linearly to changes in temperature, with the magnitude of the response being prescribed by the local lapse rates. ELA sensitivities to precipitation changes are nearly linear and are inversely correlated with the emissivity of the atmosphere. Temperature sensitivities are greatest in the inner tropics; precipitation becomes more important in the subtropics and northernmost mid-latitudes. These results can be considered an important step towards developing a framework for understanding past episodes of glacial fluctuations and ultimately for predicting glacier response to future climate changes.

  1. Can we discover dual-component thermal WIMP dark matter?

    SciTech Connect

    Profumo, Stefano; Ubaldi, Lorenzo; Sigurdson, Kris E-mail: krs@physics.ubc.ca

    2009-12-01

    We address the question of whether the upcoming generation of dark matter search experiments and colliders will be able to discover if the dark matter in the Universe has two components of weakly interacting massive particles (WIMPs). We outline a model-independent approach, and we study the specific cases of (1) direct detection with low-background 1 ton noble-gas detectors and (2) a 0.5 TeV center of mass energy electron-positron linear collider. We also analyze the case of indirect detection via two gamma-ray lines, which would provide a verification of such a discovery, although multiple gamma-ray lines can in principle originate from the annihilation of a single dark matter particle. For each search ''channel'', we outline a few assumptions to relate the very small set of parameters we consider (defining the masses of the two WIMPs and their relative abundance in the overall dark matter density) with the relevant detection rates. We then draw general conclusions on which corners of a generic dual-component dark matter scenario can be explored with current and next generation experiments. We find that in all channels the ideal setup is one where the relative mass splitting between the two WIMP species is of order 1, and where the two dark matter components contribute in a ratio close to 1:1 to the overall dark matter content of the Universe. Interestingly, in the case of direct detection, future experiments might detect multiple states even if only ? 10% of the energy-density of dark matter in the Universe is in the subdominant species.

  2. Limits on Low-Mass WIMP Dark Matter with an Ultra-Low-Energy Germanium Detector at 220 eV Threshold

    E-print Network

    Shin-Ted Lin; H. T. Wong; for the TEXONO Collaboration

    2008-10-20

    An energy threshold of (220$\\pm$10) eV was achieved at an efficiency of 50% with a four-channel ultra-low-energy germanium detector each with an active mass of 5 g\\cite{wimppaper}. This provides a unique probe to WIMP dark matter with mass below 10 GeV. With low background data taken at the Kuo-Sheng Laboratory, constraints on WIMPs in the galactic halo were derived. Both spin-independent WIMP-nucleon and spin-dependent WIMP-neutron bounds improve over previous results for WIMP mass between 3$-$6 GeV. These results, together with those on spin-dependent couplings, will be presented. Sensitivities for full-scale experiments were projected. This detector technique makes the unexplored sub-keV energy window accessible for new neutrino and dark matter experiments.

  3. Twin Higgs WIMP Dark Matter

    E-print Network

    Isabel García García; Robert Lasenby; John March-Russell

    2015-10-02

    Dark matter (DM) without a matter asymmetry is studied in the context of Twin Higgs (TH) theories in which the LHC naturalness problem is addressed. These possess a twin sector related to the Standard Model (SM) by a (broken) $\\mathbb{Z}_2$ symmetry, and interacting with the SM via a specific Higgs portal. We focus on the minimal realisation of the TH mechanism, the Fraternal Twin Higgs, with only a single generation of twin quarks and leptons, and $SU(3)'\\times SU(2)'$ gauge group. We show that a variety of natural twin-WIMP DM candidates are present (directly linked to the weak scale by naturalness), the simplest and most attractive being the $\\tau^\\prime$ lepton with a mass $m_{\\tau^\\prime} > m_{\\rm Higgs}/2$, although spin-1 $W^{\\prime\\pm}$ DM and multicomponent DM are also possible (twin baryons are strongly disfavoured by tuning). We consider in detail the dynamics of the possibly (meta)stable glueballs in the twin sector, the nature of the twin QCD phase transition, and possible new contributions to the number of relativistic degrees of freedom $\\Delta N_{\\rm eff}$. Direct detection signals are below current bounds but accessible in near future experiments. Indirect detection phenomenology is rich and requires detailed studies of twin hadronization and fragmentation to twin glueballs and quarkonia and their subsequent decay to SM, and possible light twin sector states.

  4. Twin Higgs WIMP dark matter

    NASA Astrophysics Data System (ADS)

    García García, Isabel; Lasenby, Robert; March-Russell, John

    2015-09-01

    Dark matter (DM) without a matter asymmetry is studied in the context of twin Higgs (TH) theories in which the LHC naturalness problem is addressed. These possess a twin sector related to the Standard Model (SM) by a (broken) Z2 symmetry, and interacting with the SM via a specific Higgs portal. We focus on the minimal realization of the TH mechanism, the fraternal twin Higgs, with only a single generation of twin quarks and leptons, and the S U (3 )'×S U (2 )' gauge group. We show that a variety of natural twin-WIMP DM candidates are present (directly linked to the weak scale by naturalness), the simplest and most attractive being the ?' lepton with a mass m?'>mHiggs/2 , although spin-1 W'± DM and multicomponent DM are also possible (twin baryons are strongly disfavored by tuning). We consider in detail the dynamics of the possibly (meta)stable glueballs in the twin sector, the nature of the twin QCD phase transition, and possible new contributions to the number of relativistic degrees of freedom, ? Neff . Direct detection signals are below current bounds but accessible in near-future experiments. Indirect detection phenomenology is rich and requires detailed studies of twin hadronization and fragmentation to twin glueballs and quarkonia and their subsequent decay to SM, and possible light twin sector states.

  5. Selection and characterization of a novel photoperiod-sensitive male sterile line in upland cotton.

    PubMed

    Ma, Jianhui; Wei, Hengling; Liu, Ji; Song, Meizhen; Pang, Chaoyou; Wang, Long; Zhang, Wenxiang; Fan, Shuli; Yu, Shuxun

    2013-07-01

    Upland cotton (Gossypium hirsutum L.) shows strong heterosis. However, heterosis is not widely utilized owing to the high cost of hybrid seed production. Creation of a photoperiod-sensitive genetic male sterile line could substantially reduce the cost of hybrid seed production in upland cotton. Such a mutant with virescent marker was found by space mutation in near-earth orbit and its traits had been stable after 4 years of selection in Anyang and Sanya, China. This mutant was fertile with an 11-12.5?h photoperiod when the temperature was higher than 21.5?°C and was sterile with a 13-14.5?h photoperiod. Genetic analysis indicated that both traits were controlled by a single recessive gene or two closely linked genes. Also, the cytological observations and transcriptome profiling analysis showed that the degradation of pollen grain cytoplasm should be the primary reason why the mutant line were male sterile under long-day conditions. PMID:23691935

  6. Magnetometric sensitivity optimization for nonlinear optical rotation with frequency-modulated light: Rubidium D2 line

    NASA Astrophysics Data System (ADS)

    Kimball, D. F. Jackson; Jacome, L. R.; Guttikonda, Srikanth; Bahr, Eric J.; Chan, Lok Fai

    2009-09-01

    Atomic spin polarization of alkali atoms in the ground-state can survive thousands of collisions with paraffin-coated cell walls. The resulting long spin-relaxation times achieved in evacuated, paraffin-coated cells enable precise measurement of atomic spin precession and energy shifts of ground-state Zeeman sublevels. In the present work, nonlinear magneto-optical rotation with frequency-modulated light (FM NMOR) is used to measure magnetic field-induced spin precession for rubidium atoms contained in a paraffin-coated cell. The magnetometric sensitivity of FM NMOR for the rubidium D2 line is studied as a function of light power, detuning, frequency-modulation amplitude, and rubidium vapor density. For a 5-cm-diameter cell at temperature T ?35 °C, the optimal shot-noise-projected magnetometric sensitivity is found to be 2×10-11 G/?Hz (corresponding to a sensitivity to spin precession frequency of ?10 ?Hz/?Hz or a sensitivity to Zeeman sublevel shifts of ?4×10-20 eV/?Hz ).

  7. Measuring the sensitivity of a boron-lined ion chamber. Revision 2

    SciTech Connect

    Barton, D.M.

    1992-03-01

    Boron-lined ion chambers are used to monitor external neutron flux from fissionable materials assembled at the Los Alamos Critical Assembly Experiment Facility. The sensitivity of these chambers must be measured periodically in order to detect changes in filling gas and to evaluate other factors that may affect chamber performance. We delineate a procedure to measure ion chamber response using a particular neutron source ({sup 239}PuBe) in a particular moderating geometry of polyethylene. We also discuss use of the amplifier, high-voltage power supply, recorders, and scram circuits that comprise the complete ion chamber monitoring system.

  8. Performance of a novel keratinocyte-based reporter cell line to screen skin sensitizers in vitro

    SciTech Connect

    Emter, Roger; Ellis, Graham; Natsch, Andreas

    2010-06-15

    In vitro tests are needed to replace animal tests to screen for the skin sensitization potential of chemicals. Skin sensitizers are electrophilic molecules and the Nrf2-electrophile-sensing pathway comprising the repressor protein Keap1, the transcription factor Nrf2 and the antioxidant response element (ARE) is emerging as a toxicity pathway induced by skin sensitizers. Previously, we screened a large set of chemicals in the reporter cell line AREc32, which contains an eight-fold repeat of the rat GSTA2 ARE-sequence upstream of a luciferase reporter gene in the human breast cancer cell line MCF7. This approach was now further developed to bring it closer to the conditions in the human skin and to propose a fully standardized assay. To this end, a luciferase reporter gene under control of a single copy of the ARE-element of the human AKR1C2 gene was stably inserted into HaCaT keratinocytes. A standard operating procedure was developed whereby chemicals are routinely tested at 12 concentrations in triplicate for significant induction of gene activity. We report results from this novel assay on (i) a list of reference chemicals published by ECVAM, (ii) the ICCVAM list of chemicals for validation of alternative endpoints in the LLNA and (iii) on a more general list of 67 chemicals derived from the ICCVAM database. For comparison, peptide reactivity data are presented for the same chemicals. The results indicate a good predictive value of this approach for hazard identification. Its technical simplicity, the high-throughput format and the good predictivity may make this assay a candidate for rapid validation to meet the tight deadline to replace animal tests for skin sensitization by 2013 set by the European authorities.

  9. New theories for dark matter: hunting beyond the WIMP

    E-print Network

    Fermilab Experiment E831

    New theories for dark matter: hunting beyond the WIMP Kathryn Zurek LBL Berkeley November 11, 2015 of weakly interacting massive particles (WIMPs). We consider the most compelling examples of novel dark

  10. 1. INTRODUCTION Today's mainstream interaction style (WIMP -window,

    E-print Network

    Zhai, Shumin

    1. INTRODUCTION Today's mainstream interaction style (WIMP - window, icon, menu and pointer of existing WIMP features also become more severe and obvious. There have been numerous interface inventions and studies since the basic WIMP style was developed (e.g Buxton 1986), but they have been largely restricted

  11. Proceedings of the 5th Patras Workshop on Axions, WIMPs

    E-print Network

    Proceedings of the 5th Patras Workshop on Axions, WIMPs and WISPs PATRAS 2009 July 13-17, 2009 Elektronen-Synchrotron i #12;Impressum Proceedings of the 5th Patras Workshop on Axions, WIMPs and WISPs (PATRAS 2009) July 13-17, 2009, Durham, United Kingdom Conference homepage http://axion-wimp2009.desy

  12. Status of the CDMS search for WIMPs. Andrew Sonnenschein

    E-print Network

    California at Berkeley, University of

    Status of the CDMS search for WIMPs. Andrew Sonnenschein for the CDMS collaboration 1 Abstract THE CHALLENGE OF WIMP DETECTION. One possible solution to the famous dark matter problem" is that the dark matter is in the form of weakly interacting massive particles WIMPs, which could be, for example

  13. Hunting for WIMPs with the Cryogenic Dark Matter Search

    E-print Network

    California at Berkeley, University of

    Hunting for WIMPs with the Cryogenic Dark Matter Search S.R. GOLWALA10, D.S. AKERIB1, P.D. BARNES whose goal is to detect WIMPs via elastic-scattering interactions in detectors capable of nuclear at the time that gravitational collapse began. Weakly Interacting Massive Particles, or WIMPs, are a candidate

  14. Detecting WIMPs in the Microwave Sky

    E-print Network

    P. Blasi; A. V. Olinto; C. Tyler

    2002-02-05

    The hierarchical clustering observed in cold dark matter simulations results in highly clumped galactic halos. If the dark matter in our halo is made of weakly interacting massive particles (WIMPs), their annihilation products should be detectable in the higher density and nearby clumps. We consider WIMPs to be neutralinos and calculate the synchrotron flux from their annihilation products in the presence of the Galactic magnetic field. We derive a self-consistent emission spectrum including pair annihilation, synchrotron self-absorption, and synchrotron self-Compton reactions. The resulting radiation spans microwave frequencies that can be observed over the anisotropies in the cosmic microwave background. These synchrotron sources should be identifiable as WIMP clumps, either by their spatial structure or by their distinctive radio spectrum.

  15. Establishment of three cell lines from Chinese giant salamander and their sensitivities to the wild-type and recombinant ranavirus.

    PubMed

    Yuan, Jiang-Di; Chen, Zhong-Yuan; Huang, Xing; Gao, Xiao-Chan; Zhang, Qi-Ya

    2015-01-01

    Known as lethal pathogens, Ranaviruses have been identified in diseased fish, amphibians (including Chinese giant salamander Andrias davidianus, the world's largest amphibian) and reptiles, causing organ necrosis and systemic hemorrhage. Here, three Chinese giant salamander cell lines, thymus cell line (GSTC), spleen cell line (GSSC) and kidney cell line (GSKC) were initially established. Their sensitivities to ranaviruses, wild-type Andrias davidianus ranavirus (ADRV) and recombinant Rana grylio virus carrying EGFP gene (rRGV-EGFP) were tested. Temporal transcription pattern of ranavirus major capsid protein (MCP), fluorescence and electron microscopy observations showed that both the wild-type and recombinant ranavirus could replicate in the cell lines. PMID:26070783

  16. Non-thermal WIMPs as dark radiation

    SciTech Connect

    Queiroz, Farinaldo S.

    2014-06-24

    It has been thought that only light species could behave as radiation and account for the dark radiation observed recently by Planck, WMAP9, South Pole and ATACAMA telescopes. In this work we will show GeV scale WIMPs can plausibly account for the dark radiation as well. Heavy WIMPs might mimic the effect of a half neutrino species if some fraction of them are produced non-thermally after their thermal freeze-out. In addition, we will show how BBN, CMB and Structure Formation bounds might be circumvented.

  17. A Non-thermal WIMP Miracle

    E-print Network

    Bobby Samir Acharya; Piyush Kumar; Gordon Kane; Scott Watson

    2009-09-04

    Light scalar fields with only gravitational strength couplings are typically present in UV complete theories of physics beyond the Standard Model. In the early universe it is natural for these fields to dominate the energy density, and their subsequent decay, if prior to BBN, will typically yield some dark matter particles in their decay products. In this paper we make the observation that a Non-thermal WIMP `Miracle' may result: that is, in the simplest solution to the cosmological moduli problem, non-thermally produced WIMPs can naturally account for the observed dark matter relic density. Such a solution may be generic in string theory compactifications.

  18. Photon spectra from quark generation by WIMPs

    SciTech Connect

    Cembranos, J. A. R.; Cruz-Dombriz, A.; Maroto, A. L.; Dobado, A.; Lineros, R.

    2011-05-23

    If the present dark matter (DM) in the Universe annihilates into Standard Model (SM) particles, it must contribute to the gamma ray fluxes that are detected on the Earth. The magnitude of such contribution depends on the particular DM candidate, but certain features of these spectra may be analyzed in a model-independent fashion. In this work we provide the fitting formula valid for the simulated photon spectra from WIMP annihilation into light quark-anti quark (qq-bar) channels in a wide range of WIMP masses. We illustrate our results for the cc-bar channel.

  19. Gene and microRNA expression reveals sensitivity to paclitaxel in laryngeal cancer cell line.

    PubMed

    Xu, Cheng-Zhi; Xie, Jin; Jin, Bin; Chen, Xin-Wei; Sun, Zhen-Feng; Wang, Bao-Xing; Dong, Pin

    2013-01-01

    Paclitaxel is a widely used chemotherapy drug for advanced laryngeal cancer patients. However, the fact that there are 20-40% of advanced laryngeal cancer patients do not response to paclitaxel makes it necessary to figure out potential biomarkers for paclitaxel sensitivity prediction. In this work, Hep2, a laryngeal cancer cell line, untreated or treated with lower dose of paclitaxel for 24 h, was applied to DNA microarray chips for gene and miR expression profile analysis. Expression of eight genes altered significantly following paclitaxel treatment, which was further validated by quantitative real-time PCR. Four up-regulated genes were ID2, BMP4, CCL4 and ACTG2, in which ID2 and BMP4 were implicated to be involved in several drugs sensitivity. While the down-regulated four genes, MAPK4, FASN, INSIG1 and SCD, were mainly linked to the endoplasmic reticulum and fatty acid biosynthesis, these two cell processes that are associated with drug sensitivity by increasing evidences. After paclitaxel treatment, expression of 49 miRs was significantly altered. Within these miRs, the most markedly expression-changed were miR-31-star, miR-1264, miR-3150b-5p and miR-210. While the miRs putatively modulated the mRNA expression of the most significantly expression-altered genes were miR-1264, miR-130a, miR-27b, miR-195, miR-1291, miR-214, miR-1277 and miR-1265, which were obtained by miR target prediction and miRNA target correlation. Collectively, our study might provide potential biomarkers for paclitaxel sensitivity prediction and drug resistance targets in laryngeal cancer patients. PMID:23826416

  20. Gene and microRNA expression reveals sensitivity to paclitaxel in laryngeal cancer cell line

    PubMed Central

    Xu, Cheng-Zhi; Xie, Jin; Jin, Bin; Chen, Xin-Wei; Sun, Zhen-Feng; Wang, Bao-Xing; Dong, Pin

    2013-01-01

    Paclitaxel is a widely used chemotherapy drug for advanced laryngeal cancer patients. However, the fact that there are 20-40% of advanced laryngeal cancer patients do not response to paclitaxel makes it necessary to figure out potential biomarkers for paclitaxel sensitivity prediction. In this work, Hep2, a laryngeal cancer cell line, untreated or treated with lower dose of paclitaxel for 24 h, was applied to DNA microarray chips for gene and miR expression profile analysis. Expression of eight genes altered significantly following paclitaxel treatment, which was further validated by quantitative real-time PCR. Four up-regulated genes were ID2, BMP4, CCL4 and ACTG2, in which ID2 and BMP4 were implicated to be involved in several drugs sensitivity. While the down-regulated four genes, MAPK4, FASN, INSIG1 and SCD, were mainly linked to the endoplasmic reticulum and fatty acid biosynthesis, these two cell processes that are associated with drug sensitivity by increasing evidences. After paclitaxel treatment, expression of 49 miRs was significantly altered. Within these miRs, the most markedly expression-changed were miR-31-star, miR-1264, miR-3150b-5p and miR-210. While the miRs putatively modulated the mRNA expression of the most significantly expression-altered genes were miR-1264, miR-130a, miR-27b, miR-195, miR-1291, miR-214, miR-1277 and miR-1265, which were obtained by miR target prediction and miRNA target correlation. Collectively, our study might provide potential biomarkers for paclitaxel sensitivity prediction and drug resistance targets in laryngeal cancer patients. PMID:23826416

  1. Mutation and repair in an ultraviolet-sensitive Chinese hamster ovary cell line

    SciTech Connect

    Wood, R.D.

    1981-01-01

    An ultraviolet (UV) light-sensitive mutant of Chinese hamster ovary cells (CHO) has been isolated and characterized with respect to a number of post-irradiation responses. The UV-sensitive mutant, termed 43-3B, was isolated by replica plating of mutagenized CHO cells, followed by a challenge with UV radiation. 43-3B has the same growth rate and chromosome number as the wild-type CHO-9. 43-3B is hypersensitive to the lethal effects of UV light (D/sub 0/ of 0.3 J/m/sup 2/ as compared to 3.2 J/m/sup 2/ for the wild-type). A marked UV-hypermutability is observed in 43-3B as compared to the wild-type. The UV-sensitive mutant is also sensitive to killing by simulated solar light, although the D/sub 0/ ratio is not as great as for germicidal UV. A much reduced ability of recover control rates of semiconservative DNA synthesis after UV irradiation was observed in the repair-deficient 43-3B cell line, suggesting that the removal of UV-induced replication blocks by excision repair is the most important factor in allowing recovery of UV-inhibited DNA synthesis. Recovery of colony-forming ability between fractionated UV exposures was observed in the wild-type CHO-9, but little recovery was seen in 43-3B. This indicates that excision repair capability can also be important in split-fluence recovery.

  2. Systematic assessment of analytical methods for drug sensitivity prediction from cancer cell line data.

    PubMed

    Jang, In Sock; Neto, Elias Chaibub; Guinney, Juistin; Friend, Stephen H; Margolin, Adam A

    2014-01-01

    Large-scale pharmacogenomic screens of cancer cell lines have emerged as an attractive pre-clinical system for identifying tumor genetic subtypes with selective sensitivity to targeted therapeutic strategies. Application of modern machine learning approaches to pharmacogenomic datasets have demonstrated the ability to infer genomic predictors of compound sensitivity. Such modeling approaches entail many analytical design choices; however, a systematic study evaluating the relative performance attributable to each design choice is not yet available. In this work, we evaluated over 110,000 different models, based on a multifactorial experimental design testing systematic combinations of modeling factors within several categories of modeling choices, including: type of algorithm, type of molecular feature data, compound being predicted, method of summarizing compound sensitivity values, and whether predictions are based on discretized or continuous response values. Our results suggest that model input data (type of molecular features and choice of compound) are the primary factors explaining model performance, followed by choice of algorithm. Our results also provide a statistically principled set of recommended modeling guidelines, including: using elastic net or ridge regression with input features from all genomic profiling platforms, most importantly, gene expression features, to predict continuous-valued sensitivity scores summarized using the area under the dose response curve, with pathway targeted compounds most likely to yield the most accurate predictors. In addition, our study provides a publicly available resource of all modeling results, an open source code base, and experimental design for researchers throughout the community to build on our results and assess novel methodologies or applications in related predictive modeling problems. PMID:24297534

  3. Parallel Dipole Line System: A Novel Magnetic Trap and High Sensitivity Hall system

    NASA Astrophysics Data System (ADS)

    Gunawan, Oki; Virgus, Yudistira; Tai, Kong Fai

    2015-03-01

    A system that could trap cylindrical objects such as semiconductor nanowires provides a route towards self-assembled fabrication of bottom-up nanowire integrated circuit. We show that such a trap can be realized using a simple parallel dipole line (PDL) system which can be experimentally realized using diametrically-magnetized magnets with a diamagnetic rod as the trapped object. This system produces a fascinating 1D camelback potential profile at the center plane and yields a new technique for magnetic susceptibility measurement for the trapped rod. This system also yields a surprising application for a high sensitivity Hall measurement system which plays a decisive role in extracting low carrier mobility in earth abundant kesterite solar cell.

  4. In-line interferometer for direction-sensitive displacement measurements by optical feedback detection

    SciTech Connect

    Tarun, Alvarado; Jecong, Julius; Saloma, Caesar

    2005-12-01

    We demonstrate a compact in-line interferometer for direction-sensitive displacement measurement by optical feedback detection with a semiconductor laser (SL) light source. Two reflected beams from a semitransparent reference mirror and a reflecting test object interfere in the SL medium, causing a variation in its output power. The reference mirror is located between the SL output facet and the test object. The performance of the interferometer is investigated numerically and experimentally to determine its optimal operating conditions. We have verified the operating conditions where the behavior of the SL output power profile could indicate accurately the displacement magnitude and direction of the moving test object. The profile behavior is robust against variations in optical feedback and scale of the interferometer configuration.

  5. Polarization-sensitive optical coherence tomography system tolerant to fiber disturbances using a line camera.

    PubMed

    Marques, Manuel J; Rivet, Sylvain; Bradu, Adrian; Podoleanu, Adrian

    2015-08-15

    This Letter presents a spectral-domain, polarization-sensitive optical coherence tomography (PS-OCT) system, where the light collection from the two arms of the interferometer is performed exclusively using single-mode fibers and couplers, and the two orthogonal polarization components are sequentially detected by a single line camera. Retardance measurements can be affected by polarimetric effects because of fiber birefringence and diattenuation in fiber couplers. This configuration bypasses such issues by performing polarization selection before the collection fiber through the combination of a polarization rotator and a linear polarizer. Retardance calibration is achieved with a Berek compensator. Similar net retardance maps of a birefringent phantom are obtained for two different settings of induced fiber birefringence, effectively demonstrating the tolerance of the configuration to fiber-based disturbances. PMID:26274678

  6. Searches for WIMP Annihilation with GLAST

    SciTech Connect

    Wai, L.; ,

    2005-06-21

    We describe signatures for WIMP annihilation in the gamma ray sky which can be observed by the GLAST mission, scheduled for launch in 2007. We review the search regions, which range from galactic substructure in the Milky Way all the way out to cosmological sources.

  7. On the Annihilation Rate of WIMPs

    E-print Network

    Matthew Baumgart; Ira Z. Rothstein; Varun Vaidya

    2015-10-08

    We develop a formalism that allows one to systematically calculate the WIMP annihilation rate into gamma rays whose energy far exceeds the weak scale. A factorization theorem is presented which separates the radiative corrections stemming from initial state potential interactions from loops involving the final state. This separation allows us to go beyond the fixed order calculation, which is polluted by large infrared logarithms. For the case of Majorana WIMPs transforming in the adjoint representation of SU(2), we present the result for the resummed rate at leading double log accuracy in terms of two initial state partial wave matrix elements and one hard matching coefficient. For a given model, one may calculate the cross section by calculating the tree level matching coefficient and determining the value of a local four fermion operator. We find that the effects of resummation can be as large as 100% for a 20 TeV WIMP. The generalization of the formalism to other types of WIMPs is discussed.

  8. WIMPS Are Stronger When They Stick Together

    E-print Network

    Angela V. Olinto; Pasquale Blasi; Craig Tyler

    2001-08-03

    Weakly interacting massive particles (WIMPs) remain the strongest candidates for the dark matter in the Universe. If WIMPs are the dark matter, they will form galactic halos according to the hierarchical clustering observed in N-body simulations. Cold dark matter (CDM) simulations show that large dark matter structures such as galactic and cluster halos are formed by the merging of many smaller clumps of dark matter. Each clump or halo is characterized by a centrally cusped density profile that can enhance the rate of WIMP annihilation and make the annihilation products more easily detectable. Electrons and positrons generated as decay products of WIMP annihilation emit synchrotron radiation in the Galactic magnetic field. We study the synchrotron signature from the clumps of dark matter in our Galactic halo. We find that the emission in the radio and microwave region of the electromagnetic spectrum can be above the CMB anisotropy level and should be detectable by CMB anisotropy experiments. Depending on the density profile of dark matter clumps, hundreds of clumps can have detectable fluxes and angular sizes.

  9. Oh to Be Rid of Administrative Wimps!

    ERIC Educational Resources Information Center

    Weissberg, Robert

    2007-01-01

    Contemporary university administrators are usually wimps, and timidity in facing easily enraged campus radicals only invites outrageous demands which, in turn, subvert intellectual life. This must be changed. For much of human history leaders had to display physical valor and this trait should be restored to the college administrator job…

  10. Evaluation of the drug sensitivity and expression of 16 drug resistance-related genes in canine histiocytic sarcoma cell lines

    PubMed Central

    ASADA, Hajime; TOMIYASU, Hirotaka; GOTO-KOSHINO, Yuko; FUJINO, Yasuhito; OHNO, Koichi; TSUJIMOTO, Hajime

    2015-01-01

    Canine histiocytic sarcoma (HS) is an aggressive tumor type originating from histiocytic cell lineages. This disease is characterized by poor response to chemotherapy and short survival time. Therefore, it is of critical importance to identify and develop effective antitumor drugs against HS. The objectives of this study were to examine the drug sensitivities of 10 antitumor drugs. Using a real-time RT-PCR system, the mRNA expression levels of 16 genes related to drug resistance in 4 canine HS cell lines established from dogs with disseminated HS were determined and compared to 2 canine lymphoma cell lines (B-cell and T-cell). These 4 canine HS cell lines showed sensitivities toward microtubule inhibitors (vincristine, vinblastine and paclitaxel), comparable to those in the canine B-cell lymphoma cell line. Moreover, it was shown that P-gp in the HS cell lines used in this study did not have enough function to efflux its substrate. Sensitivities to melphalan, nimustine, methotrexate, cytarabine, doxorubicin and etoposide were lower in the 4 HS cell lines than in the 2 canine lymphoma cell lines. The data obtained in this study using cultured cell lines could prove helpful in the developing of advanced and effective chemotherapies for treating dogs that are suffering from HS. PMID:25715778

  11. Determining the WIMP mass using direct detection experiments

    E-print Network

    Anne M Green

    2007-08-07

    We study the accuracy with which the WIMP mass could be determined by a superCDMS-like direct detection experiment, given optimistic assumptions about the detector set-up and WIMP properties. We consider WIMPs with an interaction cross-section of \\sigma_{\\rm p} = 10^{-7} {\\rm pb} (just below current exclusion limits) and assume, initially, that the local WIMP velocity distribution and density are known and that the experiment has negligible background. For light WIMPs (mass significantly less than that of the target nuclei) small variations in the WIMP mass lead to significant changes in the energy spectrum. Conversely for heavy WIMPs the energy spectrum depends only weakly on the WIMP mass. Consequently it will be far easier to measure the WIMP mass if it is light than if it is heavy. With exposures of {\\cal E}= 3 \\times 10^{3}, 3 \\times 10^{4} and 3 \\times 10^{5} {\\rm kg day} (corresponding, roughly, to the three proposed phases of SuperCDMS) it will be possible, given the optimistic assumptions mentioned above, to measure the mass of a light WIMP with an accuracy of roughly 25%, 15% and 2.5 % respectively. These numbers increase with increasing WIMP mass, and for heavy WIMPs, m_{\\chi} > {\\cal O}(500 {\\rm GeV}), even with a large exposure it will only be possible to place a lower limit on the mass. Finally we discuss the validity of the various assumptions made, and the consequences if these assumptions are not valid. In particular if the local WIMP distribution is composed of a number of discrete streams it will not be possible to determine the WIMP mass.

  12. Silicon fin line edge roughness determination and sensitivity analysis by Mueller matrix spectroscopic ellipsometry based scatterometry

    NASA Astrophysics Data System (ADS)

    Dixit, Dhairya; O'Mullane, Samuel; Sunkoju, Sravan; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe; Keller, Nick; Race, Joseph; Muthinti, Gangadhara Raja; Diebold, Alain C.

    2015-03-01

    Measurement and control of line edge roughness (LER) is one of the most challenging issues facing patterning technology. As the critical dimensions (CD) of patterned structures decrease, LER of only a few nanometers can negatively impact device performance. Here, Mueller matrix spectroscopic ellipsometry (MMSE) based scatterometry is used to determine LER in periodic line-space structures in 28 nm pitch Si fin samples fabricated by directed selfassembly (DSA) patterning. The optical response of the Mueller matrix (MM) elements is influenced by structural parameters like pitch, CD, height, and side-wall angle (SWA), as well as the optical properties of the materials. Evaluation and decoupling MM element response to LER from other structural parameters requires sensitivity analysis using simulations of optical models that include LER. Here, an approach is developed that quantifies Si fin LER by comparing the optical responses generated by systematically varying the grating shape and measurement conditions. Finally, the validity of this approach is established by comparing the results obtained from top down scanning electron microscope (SEM) images and cross-sectional TEM image of the 28 nm pitch Si fins.

  13. Prodigiosin down-regulates survivin to facilitate paclitaxel sensitization in human breast carcinoma cell lines

    SciTech Connect

    Ho, T.-F.; Peng, Y.-T.; Chuang, S.-M.; Lin, S.-C.; Feng, B.-L.; Lu, C.-H.; Yu, W.-J.; Chang, J.-S. Chang, C.-C.

    2009-03-01

    Prodigiosin is a bacterial metabolite with potent anticancer activity, which is attributed to its proapoptotic effect selectively active in malignant cells. Still, the molecular mechanisms whereby prodigiosin induces apoptosis remain largely unknown. In particular, the role of survivin, a vital inhibitor of apoptosis, in prodigiosin-induced apoptosis has never been addressed before and hence was the primary goal of this study. Our results showed that prodigiosin dose-dependently induced down-regulation of survivin in multiple breast carcinoma cell lines, including MCF-7, T-47D and MDA-MB-231. This down-regulation is mainly regulated at the level of transcription, as prodigiosin reduced the levels of both survivin mRNA and survivin promoter activity but failed to rescue survivin expression when proteasome-mediated degradation is abolished. Importantly, overexpression of survivin rendered cells more resistant to prodigiosin, indicating an essential role of survivin down-regulation in prodigiosin-induced apoptosis. In addition, we found that prodigiosin synergistically enhanced cell death induced by paclitaxel, a chemotherapy drug known to up-regulate survivin that in turn confers its own resistance. This paclitaxel sensitization effect of prodigiosin is ascribed to the lowering of survivin expression, because prodigiosin was shown to counteract survivin induction by paclitaxel and, notably, the sensitization effect was severely abrogated in cells that overexpress survivin. Taken together, our results argue that down-regulation of survivin is an integral component mediating prodigiosin-induced apoptosis in human breast cancer cells, and further suggest the potential of prodigiosin to sensitize anticancer drugs, including paclitaxel, in the treatment of breast cancer.

  14. The Sensitivity of West African Squall Line Water Budgets to Land Cover

    NASA Technical Reports Server (NTRS)

    Mohr, Karen I.; Baker, R. David; Tao, Wei-Kuo; Famiglietti, James S.; Starr, David OC. (Technical Monitor)

    2001-01-01

    This study used a two-dimensional coupled land/atmosphere (cloud-resolving) model to investigate the influence of land cover on the water budgets of squall lines in the Sahel. Study simulations used the same initial sounding and one of three different land covers, a sparsely vegetated semi-desert, a grassy savanna, and a dense evergreen broadleaf forest. All simulations began at midnight and ran for 24 hours to capture a full diurnal cycle. In the morning, the latent heat flux, boundary layer mixing ratio, and moist static energy in the boundary layer exhibited notable variations among the three land covers. The broadleaf forest had the highest latent heat flux, the shallowest, moistest, slowest growing boundary layer, and significantly more moist static energy per unit area than the savanna and semi-desert. Although all simulations produced squall lines by early afternoon, the broadleaf forest had the most intense, longest-lived squall lines with 29% more rainfall than the savanna and 37% more than the semi-desert. The sensitivity of the results to vegetation density, initial sounding humidity, and grid resolution was also assessed. There were greater differences in rainfall among land cover types than among simulations of the same land cover with varying amounts of vegetation. Small changes in humidity were equivalent in effect to large changes in land cover, producing large changes in the condensate and rainfall. Decreasing the humidity had a greater effect on rainfall volume than increasing the humidity. Reducing the grid resolution from 1.5 km to 0.5 km decreased the temperature and humidity of the cold pools and increased the rain volume.

  15. Differentiating hidden sector dark matter from light WIMPs with Germanium detectors

    E-print Network

    R. Foot

    2012-11-14

    Light WIMP dark matter and hidden sector dark matter have been proposed to explain the DAMA, CoGeNT and CRESST-II data. Both of these approaches feature spin independent elastic scattering of dark matter particles on nuclei. Light WIMP dark matter invokes a single particle species which interacts with ordinary matter via contact interactions. By contrast hidden sector dark matter is typically multi-component and is assumed to interact via the exchange of a massless mediator. Such hidden sector dark matter thereby predicts a sharply rising nuclear recoil spectrum, $dR/dE_R \\sim 1/E_R^2$ due to this dynamics, while WIMP dark matter predicts a spectrum which depends sensitively on the WIMP mass, $m_\\chi$. We compare and contrast these two very different possible origins of the CoGeNT low energy excess. In the relevant energy range, the recoil spectra predicted by these two theories approximately agree provided $m_\\chi \\simeq 8.5$ GeV - close to the value favoured from fits to the CoGeNT and CDMS low energy data. Forthcoming experiments including C-4, CDEX, and the MAJORANA demonstrator, are expected to provide reasonably precise measurements of the low energy Germanium recoil spectrum, including the annual modulation amplitude, which should differentiate between these two theoretical possibilities.

  16. A Search for WIMPs with the First Five-Tower Data from CDMS

    E-print Network

    CDMS Collaboration

    2008-03-31

    We report first results from the Cryogenic Dark Matter Search (CDMS II) experiment running with its full complement of 30 cryogenic particle detectors at the Soudan Underground Laboratory. This report is based on the analysis of data acquired between October 2006 and July 2007 from 15 Ge detectors (3.75 kg), giving an effective exposure of 121.3 kg-d (averaged over recoil energies 10--100 keV, weighted for a weakly interacting massive particle (WIMP) mass of 60 \\gev). A blind analysis, incorporating improved techniques for event reconstruction and data quality monitoring, resulted in zero observed events. This analysis sets an upper limit on the WIMP-nucleon spin-independent cross section of 6.6$\\times10^{-44}$ cm$^2$ (4.6$\\times10^{-44}$ cm$^2$ when combined with previous CDMS Soudan data) at the 90% confidence level for a WIMP mass of 60 \\gev. By providing the best sensitivity for dark matter WIMPs with masses above 42 GeV/c$^2$, this work significantly restricts the parameter space for some of the favored supersymmetric models.

  17. Annihilation Lines from Dark Matter with the Fermi-LAT

    SciTech Connect

    Ylinen, Tomi

    2010-06-23

    Dark matter is today one of the most intriguing but so far unresolved issues in physics. Many extensions of the Standard Model of particle physics predict a stable Weakly Interacting Massive Particle (WIMP) that may annihilate directly into two gamma-rays. If the WIMPs are non-relativistic, the gamma-rays from this channel will have an energy equal to the mass of the WIMP. The signature caused by this annihilation is a spectral line, smeared out only by the energy resolution of the detector. The signal would be a ''smoking gun'' for dark matter, since no other astrophysical source should be able to produce it. We present here the preliminary results from the search for a dark matter line on a limited data set from the Fermi Large Area Telescope (LAT), the main instrument onboard the Fermi Gamma-ray Space Telescope, which was successfully launched on June 11, 2008. The Fermi-LAT is a pair-conversion detector for gamma-rays with an energy range from 20 MeV to 300 GeV and has an unprecedented resolution and sensitivity.

  18. Detecting Dark Matter annihilation lines with Fermi

    SciTech Connect

    Ylinen, Tomi; Edmonds, Yvonne; Bloom, Elliott D.; Conrad, Jan; /Royal Inst. Tech., Stockholm /Kalmar U. /KIPAC, Menlo Park /SLAC /Stockholm U.

    2009-05-15

    Dark matter constitutes one of the most intriguing but so far unresolved issues in physics today. In many extensions of the Standard Model the existence of a stable Weakly Interacting Massive Particle (WIMP) is predicted. The WIMP is an excellent dark matter particle candidate and one of the most interesting scenarios include an annihilation of two WIMPs into two gamma-rays. If the WIMPs are assumed to be non-relativistic, the resulting photons will both have an energy equal to the mass of the WIMP and manifest themselves as a monochromatic spectral line in the energy spectrum. This type of signal would represent a 'smoking gun' for dark matter, since no other known astrophysical process should be able to produce it. In these proceedings we give an overview of the different approaches to a search for dark matter lines that the Fermi-LAT collaboration is pursuing and the various challenges involved.

  19. KRAS G13D Mutation and Sensitivity to Cetuximab or Panitumumab in a Colorectal Cancer Cell Line Model

    PubMed Central

    Kumar, Shalini Sree; Price, Timothy J.; Mohyieldin, Omar; Borg, Matthew; Townsend, Amanda

    2014-01-01

    ABSTRACT BACKGROUND: The treatment of metastatic colorectal cancer (mCRC) includes drugs targeting the epidermal growth factor receptor (EGFR). Mutation in codon 12 or 13 in the Kirsten rat sarcoma viral oncogene homolog (KRAS) gene, downstream of the EGFR, evokes constitutive activation of the RAS/RAF/MAPK signaling pathway and correlates with resistance to anti-EGFR monoclonal antibody (mAb) therapies. However, a retrospective study reported that a proportion of patients with the KRAS G13D mutation may respond to cetuximab. A similar analysis for panitumumab was not as conclusive. We sought to determine the sensitivity of CRC cell lines to cetuximab or panitumumab treatment and to investigate the correlation of the KRAS mutational status of the CRC cell lines to the responsiveness to cetuximab or panitumumab. METHODS: To determine the responsiveness of CRC cell lines to cetuximab or panitumumab, cell lines were treated with an optimized concentration of each mAb, and proliferation assays were conducted. RESULTS: After treatment with cetuximab or panitumumab, at the optimum concentration of 8 ?g/well, the KRAS G13D mutant cell lines HCT-116, LoVo, and T84 showed intermediate sensitivity to both treatments, between the resistant KRAS G12V mutant cell line SW480 and the sensitive KRAS wild-type cell line LIM1215. One of the G13D cell lines was significantly more sensitive to panitumumab than to cetuximab (P = .02). CONCLUSION: The specific KRAS mutation determines the responsiveness to anti-EGFR monoclonal antibody treatment, corresponding to reported clinical observations. PMID:24558511

  20. Direct WIMP identification: Physics performance of a segmented noble-liquid target immersed in a Gd-doped water veto

    E-print Network

    A Bueno; M C Carmona; A J Melgarejo

    2008-07-30

    We evaluate background rejection capabilities and physics performance of a detector composed of two diverse elements: a sensitive target (filled with one or two species of liquefied noble gasses) and an active veto (made of Gd-doped ultra-pure water). A GEANT4 simulation shows that for a direct WIMP search, this device can reduce the neutron background to O(1) event per year per tonne of material. Our calculation shows that an exposure of one tonne $\\times$ year will suffice to exclude spin-independent WIMP-nucleon cross sections ranging from $10^{-9}$ pb to $10^{-10}$ pb.

  1. Limits on the spin-dependent WIMP-nucleon cross-sections from the first science run of the ZEPLIN-III experiment

    E-print Network

    V. N. Lebedenko; H. M. Araujo; E. J. Barnes; A. Bewick; R. Cashmore; V. Chepel; D. Davidge; J. Dawson; T. Durkin; B. Edwards; C. Ghag; V. Graffagnino; M. Horn; A. S. Howard; A. J. Hughes; W. G. Jones; M. Joshi; G. E. Kalmus; A. G. Kovalenko; A. Lindote; I. Liubarsky; M. I. Lopes; R. Luscher; K. Lyons; P. Majewski; A. StJ. Murphy; F. Neves; J. Pinto da Cunha; R. Preece; J. J. Quenby; P. R. Scovell; C. Silva; V. N. Solovov; N. J. T. Smith; P. F. Smith; V. N. Stekhanov; T. J. Sumner; C. Thorne; R. J. Walker

    2009-01-27

    We present new experimental constraints on the WIMP-nucleon spin-dependent elastic cross-sections using data from the first science run of ZEPLIN-III, a two-phase xenon experiment searching for galactic dark matter WIMPs based at the Boulby mine. Analysis of $\\sim$450 kg$\\cdot$days fiducial exposure revealed a most likely signal of zero events, leading to a 90%-confidence upper limit on the pure WIMP-neutron cross-section of $\\sigma_n=1.8\\times 10^{-2}$ pb at 55 GeV/$c^2$ WIMP mass. Recent calculations of the nuclear spin structure based on the Bonn CD nucleon-nucleon potential were used for the odd-neutron isotopes $^{129}$Xe and $^{131}$Xe. These indicate that the sensitivity of xenon targets to the spin-dependent WIMP-proton interaction is much lower than implied by previous calculations, whereas the WIMP-neutron sensitivity is impaired only by a factor of $\\sim$2.

  2. Low mass stellar evolution with WIMP capture and annihilation

    E-print Network

    Pat Scott; Joakim Edsjö; Malcolm Fairbairn

    2007-11-07

    Recent work has indicated that WIMP annihilation in stellar cores has the potential to contribute significantly to a star's total energy production. We report on progress in simulating the effects of WIMP capture and annihilation upon stellar structure and evolution near supermassive black holes, using the new DarkStars code. Preliminary results indicate that low-mass stars are the most influenced by WIMP annihilation, which could have consequences for upcoming observational programs.

  3. The cytokine-dependent MUTZ-3 cell line as an in vitro model for the screening of contact sensitizers

    SciTech Connect

    Azam, Philippe; Peiffer, Jean-Luc; Chamousset, Delphine; Tissier, Marie-Helene; Bonnet, Pierre-Antoine; Vian, Laurence; Fabre, Isabelle; Ourlin, Jean-Claude . E-mail: jean-claude.ourlin@afssaps.sante.fr

    2006-04-01

    Langerhans cells (LC) are key mediators of contact allergenicity in the skin. However, no in vitro methods exist which are based on the activation process of LC to predict the sensitization potential of chemicals. In this study, we have evaluated the performances of MUTZ-3, a cytokine-dependent human monocytic cell line, in its response to sensitizers. First, we compared undifferentiated MUTZ-3 cells with several standard human cells such as THP-1, KG-1, HL-60, K-562, and U-937 in their response to the strong sensitizer DNCB and the irritant SDS by monitoring the expression levels of HLA-DR, CD54, and CD86 by flow cytometry. Only MUTZ-3 and THP-1 cells show a strong and specific response to sensitizer, while other cell lines showed very variable responses. Then, we tested MUTZ-3 cells against a wider panel of sensitizers and irritants on a broader spectrum of cell surface markers (HLA-DR, CD40, CD54, CD80, CD86, B7-H1, B7-H2, B7-DC). Of these markers, CD86 proved to be the most reliable since it detected all sensitizers, including benzocaine, a classical false negative in local lymph node assay (LLNA) but not irritants. We confirmed the MUTZ-3 response to DNCB by real-time PCR analysis. Taken together, our data suggest that undifferentiated MUTZ-3 cells may represent a valuable in vitro model for the screening of potential sensitizers.

  4. Resonant scattering and recombination of pseudodegenerate WIMPs

    SciTech Connect

    Pospelov, Maxim; Ritz, Adam

    2008-09-01

    We consider the direct and indirect detection signatures of weakly interacting massive particles (WIMPs) {chi}{sup 0} in kinematic regimes with a heavier, but nearly degenerate, charged state {chi}{sup {+-}}. For small splittings of O(10) MeV, the scattering of WIMPs off nuclei may be dominated by inelastic recombination processes mediated by the formation of ({chi}{sup -}N) bound states, leading to a distinct signature for direct detection. These cross sections are bound primarily by limits on the abundance of heavy isotopes, and may be considerably larger than the elastic scattering cross section in more conventional models. If the mass splitting is too large for recombination to occur, there may still be a significant resonant enhancement of loop-induced electromagnetic form factors of the WIMP, which can enhance the elastic scattering cross section. We also discuss how this regime affects the annihilation cross section and indirect detection signatures, and note the possibility of a significant mono-energetic {gamma} signal, mediated by resonant processes near the ({chi}{sup +}{chi}{sup -}) bound-state threshold.

  5. Can Heavy WIMPs Be Captured by the Earth?

    E-print Network

    Andrew Gould; S. M. Khairul Alam

    1999-11-16

    If weakly interacting massive particles (WIMPs) in bound solar orbits are systematically driven into the Sun by solar-system resonances (as Farinella et al. have shown is the case for many Earth-crossing asteroids), then the capture of high-mass WIMPs by the Earth would be affected dramatically because high-mass WIMPs are captured primarily from bound orbits. WIMP capture would be eliminated for M_x>630 GeV and would be highly suppressed for M_x>~150 GeV. Annihilation of captured WIMPs and anti-WIMPs is expected to give rise to neutrinos coming from the Earth's center. The absence of such a neutrino signal has been used to place limits on WIMP parameters. At present, one does not know if typical WIMP orbits are in fact affected by these resonances. Until this question is investigated and resolved, one must (conservatively) assume that they are. Hence, limits on high-mass WIMP parameters are significantly weaker than previously believed.

  6. New limits on spin-independent and spin-dependent couplings of low-mass WIMP dark matter with a germanium detector at a threshold of 220 eV

    SciTech Connect

    Lin, S. T.; Li, H. B.; Lin, S. K.; Wong, H. T.; Lin, C. W.; Lin, F. K.; Wang, J. J.; Wang, Y. R.; Wu, S. C.; Li, X.; Fang, B. B.; He, D.; Yue, Q.; Deniz, M.; Li, J.; Ruan, X. C.; Zhou, Z. Y.; Singh, V.; Soma, A. K.

    2009-03-15

    An energy threshold of (220{+-}10) eV was achieved at an efficiency of 50% with a four-channel ultralow-energy germanium detector, each with an active mass of 5 g. This provides a unique probe to weakly interacting massive particles (WIMP) dark matter with mass below 10 GeV. With a data acquisition live time of 0.338 kg-day at the Kuo-Sheng Laboratory, constraints on WIMPs in the galactic halo were derived. The limits improve over previous results on both spin-independent WIMP-nucleon and spin-dependent WIMP-neutron cross-sections for WIMP mass between 3 and 6 GeV. Sensitivities for full-scale experiments are projected. This detector technique makes the unexplored sub-keV energy window accessible for new neutrino and dark matter experiments.

  7. The role of sensitivity of ALA (PpIX)-based PDT on Human embryonic kidney cell line (HEK293T)

    NASA Astrophysics Data System (ADS)

    Fakhar-e-Alam, M.; Atif, M.; Rehman, T.; Sadia, H.; Firdous, S.

    2011-08-01

    Present study evaluates the effects of photodynamic therapy (PDT) with aminolevulinic acid (5-ALA) as photo sensitizer using Human embryonic kidney (HEK293T) cell line as an experimental model. Porphyrins derivatives are used as active cytotoxic antitumor agents in PDT. Above mentioned cell line were irradiated with red light (a diode laser, ? = 635 nm) at different doses (0-160 J/cm2) of light. The influence/effectiveness of incubation time, various concentrations of aminolevulinic acid (5-ALA) and light doses on the cellular viability was studied. HEK293T cells were deliberated by exposing the ALA-PpIX (0-1000 ?g/ml) of concentrations. The optimal uptakes of photosensitizer (PS) in cell lines were investigated by means of spectro photo metric measurements. Cells viability was determined by means of neutral red assay (NRA). It was observed that alone, neither photosensitizer nor light dose have significant effect on cells viability, but optimal concentration of PS along with suitable dose of light exhibit effective impact on the viability of cell. Our results showed that light doses of 40 J/cm2 demonstrates effective PDT outcome for HEK293T cell line when incubated with 400 ?g/ml, with wrapping up view that HEK293T cell line is very sensitive to ALA-mediated PDT as compared to cell line published in our data. At the end results has been verified by using reactive oxygen species (ROS) measure test.

  8. Vasohibin 2 Decreases the Cisplatin Sensitivity of Hepatocarcinoma Cell Line by Downregulating p53

    PubMed Central

    Han, Bei; Gu, Yuqing; Xue, Xiaofeng; Sun, Jie; Ge, Qianqian; Miao, Yi; Qian, Zhuyin

    2014-01-01

    Hepatocellular carcinoma (HCC) is a prevalent problem worldwide. Chemotherapy, especially cisplatin (CDDP)-based systemic chemotherapy, is the best option for advanced liver cancer. However, CDDP resistance is becoming common and hindering the clinical application of CDDP. Meanwhile, no consensus has been reached regarding the chemotherapeutic use of vasohibin 2 (VASH2), which promotes the angiogenesis and proliferation of cancer cells. In this work, a tissue microarray was used to observe VASH2 and its possible role in cancer treatment. Results showed that VASH2 was highly expressed in HCC tissues and was significantly correlated with cancer differentiation. To further investigate the efficacy and mechanism of the combination of VASH2 with anti-cancer drugs in liver cancer cells, we stably built VASH2 overexpression and knockdown cell lines. We found that VASH2 can influence the CDDP sensitivity and that the cell overexpression of VASH2 had a higher cell viability and lower apoptosis rate after CDDP exposure. We also observed that VASH2 overexpression downregulated wild-type p53, as well as suppressed the expression of the pro-apoptotic protein BCL2-associated X protein (Bax) and cleaved caspase-3 (CC-3) after treatment by CDDP. Conversely, the knockdown of VASH2 significantly inhibited these effects. In an in vivo chemosensitivity study, nude mice were subcutaneously injected with tumor cells and received CDDP treatment through intraperitoneal administration every 3 days. We found that VASH2 knockdown markedly limited the tumor growth and enhanced the CDDP toxicity and apoptosis of tumor cells. Western blot analysis revealed that tumor cells with downregulated VASH2 had a higher expression of wild-type p53, Bax, and CC-3 than control cells. Overall, our results indicated the novel roles of VASH2 in the chemoresistance of hepatocarcinoma cells to CDDP and suggested that VASH2 may be a promising anticancer target. PMID:24595063

  9. 'PSA-SPN' - A Parameter Sensitivity Analysis Method Using Stochastic Petri Nets: Application to a Production Line System

    SciTech Connect

    Labadi, Karim; Saggadi, Samira; Amodeo, Lionel

    2009-03-05

    The dynamic behavior of a discrete event dynamic system can be significantly affected for some uncertain changes in its decision parameters. So, parameter sensitivity analysis would be a useful way in studying the effects of these changes on the system performance. In the past, the sensitivity analysis approaches are frequently based on simulation models. In recent years, formal methods based on stochastic process including Markov process are proposed in the literature. In this paper, we are interested in the parameter sensitivity analysis of discrete event dynamic systems by using stochastic Petri nets models as a tool for modelling and performance evaluation. A sensitivity analysis approach based on stochastic Petri nets, called PSA-SPN method, will be proposed with an application to a production line system.

  10. Antitumor activity of D-mannosamine in vitro: different sensitivities among human leukemia cell lines possessing T-cell properties.

    PubMed

    Onoda, T; Morikawa, S; Harada, T; Suzuki, Y; Inoue, K; Nishigami, K

    1982-07-01

    D-Mannosamine is toxic to human malignant T-lymphoid cell lines derived from patients with T-cell leukemia. We observed heterogeneity of mannosamine susceptibility among those cell lines. The leukemic T-cell lines, subgrouped according to the degree of mannosamine inhibition on nucleic acid biosyntheses, were: Subgroup 1, HPB-MLT cells; Subgroup 2, CCRF-HSB-2 and HPB-ALL cells; and Subgroup 3, MOLT-4 cells. The most sensitive line, HPB-MLT, originated from the patient with adult T-cell leukemia. The cytotoxicity of mannosamine was potentiated by a fatty acid, sodium oleate, at concentrations that were noncytolytic, and the interaction between the two drugs was synergistic. These results would suggest that mannosamine induces changes in the membrane structure of the leukemia cells. Thus, the primary target of the tumoricidal activity of mannosamine may also be the cellular membranes. PMID:6979385

  11. Effects of a novel porphyrin-based photosensitizer on sensitive and multidrug-resistant human gastric cancer cell lines.

    PubMed

    Chen, Jingjing; Mao, Lina; Liu, Shuping; Liang, Yanling; Wang, Sicheng; Wang, Yeyu; Zhao, Qiang; Zhang, Xiaojing; Che, Yanjun; Gao, Lijing; Liu, Tianjun

    2015-10-01

    Photodynamic therapy (PDT) has been considered to be a possible candidate approach in combating multidrug resistance (MDR) phenomenon during the treatment of cancer. To investigate the photocytotoxicity of a novel porphyrin-based photosensitizer, meso-5-[?-DTPA-aminophenyl]-10, 15, 20-triphenyl-porhyrin (DTP) (Fig. 1A), on MDR cells, the intracellular DTP uptake, phototoxicity and subcellular DTP localization were studied by using a human gastric cancer MGC803 cell line and its paclitaxel selected subline MGC803/PA expressing MDR phenotype. No significant difference was observed in intracellular DTP accumulation between sensitive and resistant cell lines after exposure to 1.56 ?M concentration for 6h. DTP-PDT induced significant photocytotoxicity on both MGC803 and MGC803/PA cell lines and the photokilling was greater in MGC803 cell line in comparison to MGC803/PA. The fluence that caused 50% cell death was 4.42 and 6.29 J/cm(2) in MGC803 and MGC803/PA cell lines, respectively. The presence of Pgp inhibitors verapamil and cyclosporin A could not modify the intracellular DTP level in MGC803/PA cell line and the phototoxic effects. DTP was localized at lysosomes of MGC803 cell line but at lysosomes and mitochondria of MGC803/PA. Our results indicated that DTP-mediated PDT could eradicate gastric cancer cells whether or not they express MDR although the efficacy is slightly reduced in the MDR cells. The photokilling in MDR cells could not be altered by MDR inhibitor verapamil. The slightly different photocytotoxicity between sensitive and resistant cell lines could not explained by classical Pgp MDR and might be attributed to the differential intracellular DTP localization sites. PMID:26302181

  12. The sensitivity of lateral line receptors and their role in the behavior of Mexican blind cavefish (Astyanax mexicanus)

    PubMed Central

    Yoshizawa, Masato; Jeffery, William R.; van Netten, Sietse M.; McHenry, Matthew J.

    2014-01-01

    The characid fish species Astyanax mexicanus offers a classic comparative model for the evolution of sensory systems. Populations of this species evolved in caves and became blind while others remained in streams (i.e. surface fish) and retained a functional visual system. The flow-sensitive lateral line receptors, called superficial neuromasts, are more numerous in cavefish than in surface fish, but it is unclear whether individual neuromasts differ in sensitivity between these populations. The aims of this study were to determine whether the neuromasts in cavefish impart enhanced sensitivity relative to surface fish and to test whether this aids their ability to sense flow in the absence of visual input. Sensitivity was assessed by modeling the mechanics and hydrodynamics of a flow stimulus. This model required that we measure the dimensions of the transparent cupula of a neuromast, which was visualized with fluorescent microspheres. We found that neuromasts within the eye orbit and in the suborbital region were larger and consequently about twice as sensitive in small adult cavefish as in surface fish. Behavioral experiments found that these cavefish, but not surface fish, were attracted to a 35 Hz flow stimulus. These results support the hypothesis that the large superficial neuromasts of small cavefish aid in flow sensing. We conclude that the morphology of the lateral line could have evolved in cavefish to permit foraging in a cave environment. PMID:24265419

  13. -A Search for Dark Matter with a Continuously Sensitive Bubble Chamber

    E-print Network

    Fermilab Experiment E831

    COUPP* - A Search for Dark Matter with a Continuously Sensitive Bubble Chamber University bubble chamber as a prototype dark matter (WIMP) detector. Operating in weakly-superheated mode, the chamber will be sensitive to WIMP induced nuclear recoils above 10 keV, while rejecting background

  14. Dye sensitized photovoltaic miniaturized solar cells, used as optical sensors for line of sight detection

    NASA Astrophysics Data System (ADS)

    Cesar, Cortes Torres Carlos; Sampei, Kota; Miho, Ogawa; Masataka, Ozawa; Norihisa, Miki

    2014-11-01

    Dye sensitized photovoltaic devices have been studied as transparent and low-cost solar cells. Our group have miniaturized the cells and used them as transparent optical sensors. This paper reports the design and fabrication of the cells and avoids the cross talk among cells, which was found recently and such effect provokes hardware instability. We use these optical sensors as an eye tracking device. The sensor array detects the difference in the intensity of light reflected from the pupil and the sclera and then determines the pupil position. Each sensor consists of two electrodes and electrolyte; hence our device conformed by only four semi-circular shaped sensors on eyeglasses can detect the view angle in both horizontal and vertical directions. Manufacturing process gives us freedom to easily re-arrange, add or remove sensors. In our prior work we had good performance in stand-alone configuration. We used specialized equipment from National Instruments for our measurements. However we found that: A cell is not 100% independent from the others, is affected by the absence or presence of light at the neighbour cells. When our device is connected to other electronic devices (for data processing), all cells have the same voltage among them; therefore, all cells behave the same way when any of them is affected by light. The root cause is, due to all sensors were interconnected via a micro channel and filled with electrolyte, due to its conductive properties, electrolyte does neither need electrodes nor physical paths to conduct electricity, so it creates a liquid wire between sensors, hence the gap between them become inexistent, consequently when our device is connected to other electronic devices, due to this unique channel and by sharing a common electronic ground, this connection provokes the voltage to be the same among all sensors in the array. Our device becomes four separate voltage lines in a parallel circuit. The device was also in short circuit provoked by some overlapping paths, despite that such paths were in different layers and separated by an adhesive film of 100pm thickness, such thickness was not large enough to creates a successful dielectric to isolate the paths.

  15. 47 CFR 69.713 - Common line, traffic-sensitive, and tandem-switched transport services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-switched transport services. 69.713 Section 69.713 Telecommunication FEDERAL COMMUNICATIONS COMMISSION..., traffic-sensitive, and tandem-switched transport services. (a) Scope. This paragraph governs requests for...)(2) of this chapter. (3) The traffic-sensitive components of tandem-switched transport services,...

  16. Anticancer drug clustering based on proteomic profiles and a sensitivity database in a lung cancer cell line panel

    PubMed Central

    HINO, MITSUNORI; MATSUDA, KUNIKO; MIYANAGA, AKIHIKO; KURIBAYASI, HIDEHIKO; MIZUTANI, HIDEAKI; NORO, RINTARO; MINEGISHI, YUJI; OKANO, TETSUYA; SEIKE, MASAHIRO; KAWAKAMI, AKIKO; YOSHIMURA, AKINOBU; OGAWA, NAOKI; UESAKA, HARUKA; KUDOH, SHOJI; GEMMA, AKIHIKO

    2010-01-01

    Previously, we performed a molecular pharmacological study that applied a combination of DNA microarray-based gene expression profiling and drug sensitivity tests in vitro with a view to designing an improved chemotherapeutic strategy for advanced lung cancer. Utilizing recent key technological advances in proteomics, particularly antibody array-based methodologies, the current study aimed to examine the benefit of protein expression profiling in an analogous molecular pharmacological context. We performed protein expression analysis in a panel of lung cancer cell lines via an antibody array approach. Using a modified NCI program, we related cell line-specific proteomic profiles to the previously determined cytotoxic activity of a selection of commonly used anticancer agents, namely docetaxel, paclitaxel, gemcitabine, vinorelbine, 5-fluorouracil (5-FU), SN38, cisplatin (CDDP) and carboplatin (CBDCA). In addition, we compared these results with those obtained from our prior DNA microarray-based transcriptomic study. In our expression-drug correlation analysis using antibody array, gemcitabine consistently belonged to an isolated cluster. Docetaxel, paclitaxel, 5-FU, SN38, CBDCA and CDDP were gathered together into one large cluster. These results coincided with those generated by the prior transcriptomic study. Various genes were commonly listed that differentiated gemcitabine from the others. The identified factors associated with drug sensitivities were different between both analyses. Our proteomic profiling data provided confirmation of the previous transcript expression-drug sensitivity correlation analysis. These results suggest that chemotherapy regimens that include gemcitabine should be evaluated in second-line chemotherapy in cases where the first-line chemotherapy did not include this drug. Protein expression-drug sensitivity correlations in lung cancer cells in vitro may provide useful information in determining the most appropriate therapeutic options for lung cancer patients. PMID:23136590

  17. Beyond WIMP: Designing NUIs to Sup-port Productivity Document Tasks

    E-print Network

    Deussen, Oliver

    Beyond WIMP: Designing NUIs to Sup- port Productivity Document Tasks Abstract After decades of WIMP and applications invade the market. In the professional office world, however, WIMP software still prevails for so to start to change, interface designers and engineers need to free them- selves from their lingering WIMP

  18. EXTENDING THE SENSITIVITY TO THE DETECTION OF WIMP DARK MATTER

    E-print Network

    California at Berkeley, University of

    of the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 2 The Dark Matter Problem 28 2 and structure of the Run . . . . . . . . . . . . . . 70 3.2.3 The Icebox and Dilution Refrigerator

  19. New class of biological detectors for WIMPs

    NASA Astrophysics Data System (ADS)

    Drukier, A. K.; Cantor, Ch.; Chonofsky, M.; Church, G. M.; Fagaly, R. L.; Freese, K.; Lopez, A.; Sano, T.; Savage, C.; Wong, W. P.

    2014-07-01

    Weakly Interacting Massive Particles (WIMPs) may constitute a large fraction of the matter in the Universe. There are excess events in the data of DAMA/LIBRA, CoGeNT, CRESST-II, and recently CDMS-Si, which could be consistent with WIMP masses of approximately 10 GeV/c2. However, for MDM > 10 GeV/c2 null results of the CDMS-Ge, XENON, and LUX detectors may be in tension with the potential detections for certain dark matter scenarios and assuming a certain light response. We propose the use of a new class of biological dark matter (DM) detectors to further examine this light dark matter hypothesis, taking advantage of new signatures with low atomic number targets. Two types of biological DM detectors are discussed here: DNA-based detectors and enzymatic reactions (ER) based detectors. In the case of DNA-based detectors, we discuss a new implementation. In the case of ER detectors, there are four crucial phases of the detection process: (a) change of state due to energy deposited by a particle; (b) amplification due to the release of energy derived from the action of an enzyme on its substrate; (c) sustainable but nonexplosive enzymatic reaction; (d) self-termination due to the denaturation of the enzyme, when the temperature is raised. This paper provides information of how to design as well as optimize these four processes.

  20. BBN And The CMB Constrain Light, Electromagnetically Coupled WIMPs

    E-print Network

    Kenneth M. Nollett; Gary Steigman

    2014-04-04

    (Abridged) In the presence of a light WIMP (WIMP, its couplings to standard model particles, its mass m_chi, and the number of equivalent neutrinos beyond the standard model, Delta N_nu. These degeneracies cannot be broken by the CMB constraint on the effective number of neutrinos, N_eff. However, big bang nucleosynthesis (BBN) is affected by a light WIMP and equivalent neutrinos, so the combination of BBN and CMB can break some of the degeneracies. Here, BBN predictions for abundances in the presence of a light WIMP and equivalent neutrinos are explored, and estimates of their observationally determined relic abundances are used to limit m_chi, Delta N_nu, and the present Universe baryon density (Omega_B h^2). These constraints are explored for Majorana and Dirac fermion WIMPs, as well as for real and complex scalar WIMPs that couple to electrons, positrons, and photons. In a separate paper this analysis is repeated for WIMPs that couple only to the standard model neutrinos, and constraints for the two cases are contrasted. Without a light WIMP but allowing for equivalent neutrinos, the combined BBN and CMB constraints favor N_eff = 3.46 +/- 0.17, Omega_B h^2 = 0.0224 +/- 0.0003, and Delta N_nu = 0.40 +/- 0.17. In this case, standard BBN (Delta N_nu = 0) is disfavored at ~98% confidence, and the presence of one sterile neutrino (Delta N_nu = 1) is disfavored at > 99% confidence. Allowing a light WIMP and Delta N_nu equivalent neutrinos together, the combined BBN and CMB data provide lower limits to the WIMP masses (> 0.5 - 5 MeV) that depend on the nature of the WIMP, favor m_chi ~8 MeV slightly over no WIMP, and loosen constraints on equivalent neutrinos, Delta N_nu = 0.65+0.46-0.35. While Delta N_nu = 0 is still disfavored at ~95% confidence with a light WIMP, Delta N_nu = 1 is now allowed.

  1. TREX-DM: a low background Micromegas-based TPC for low mass WIMP detection

    NASA Astrophysics Data System (ADS)

    Iguaz, F. J.; Garza, J. G.; Aznar, F.; Castel, J. F.; Cebrián, S.; Dafni, T.; García, J. A.; Gómez, H.; González-Diaz, D.; Irastorza, I. G.; Lagraba, A.; Luzón, G.; Peiró, A.; Rodríguez, A.

    2015-11-01

    Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we present the TREX-DM experiment, a low background Micromegas-based TPC for low-mass WIMP detection. Its main goal is the operation of an active detection mass ~0.300 kg, with an energy threshold below 0.4 keVee and fully built with previously selected radiopure materials. This article describes the actual setup, the first results of the comissioning in Ar+2%iC4H10 at 1.2 bar and the future updates for a possible physics run at the Canfranc Underground Laboratory in 2016. A first background model is also presented, based on Geant4 simulations and a muon/electron discrimination method. In a conservative scenario, TREX-DM could be sensitive to DAMA/LIBRA and other hints of positive WIMPs signals, with some space for improvement with a neutron/electron discrimination method or the use of other light gases.

  2. TREX-DM: a low background Micromegas-based TPC for low-mass WIMP detection

    E-print Network

    Iguaz, F J; Aznar, F; Castel, J F; Cebrian, S; Dafni, T; Garcia, J A; Irastorza, I G; Lagraba, A; Luzon, G; Peiro, A

    2016-01-01

    Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we describe the TREX-DM experiment, a low background Micromegas-based TPC for low-mass WIMP detection. Its main goal is the operation of an active detection mass $\\sim$0.3 kg, with an energy threshold below 0.4 keVee and fully built with previously selected radiopure materials. This work describes the commissioning of the actual setup situated in a laboratory on surface and the updates needed for a possible physics run at the Canfranc Underground Laboratory (LSC) in 2016. A preliminary background model of TREX-DM is also presented, based on a Geant4 simulation, the simulation of the detector's response and two discrimination methods: a conservative muon/electron and one based on a neutron source. Based on this background model, TREX-DM could be competitive in the search for low-mass WIMPs. In particular it could be sensitive, e.g., to t...

  3. Nuclear structure aspects of spin-independent WIMP scattering off xenon

    E-print Network

    L. Vietze; P. Klos; J. Menéndez; W. C. Haxton; A. Schwenk

    2015-02-19

    We study the structure factors for spin-independent WIMP scattering off xenon based on state-of-the-art large-scale shell-model calculations, which are shown to yield a good spectroscopic description of all experimentally relevant isotopes. Our results are based on the leading scalar one-body currents only. At this level and for the momentum transfers relevant to direct dark matter detection, the structure factors are in very good agreement with the phenomenological Helm form factors used to give experimental limits for WIMP-nucleon cross sections. In contrast to spin-dependent WIMP scattering, the spin-independent channel, at the one-body level, is less sensitive to nuclear structure details. In addition, we explicitly show that the structure factors for inelastic scattering are suppressed by ~ 10^{-4} compared to the coherent elastic scattering response. This implies that the detection of inelastic scattering will be able to discriminate clearly between spin-independent and spin-dependent scattering. Finally, we provide fits for all calculated structure factors.

  4. TREX-DM: a low background Micromegas-based TPC for low mass WIMP detection

    E-print Network

    F. J. Iguaz; J. G. Garza; F. Aznar; J. F. Castel; S. Cebrian; T. Dafni; J. A. Garcia; H. Gomez; D. Gonzalez-Diaz; I. G. Irastorza; A. Lagraba; G. Luzon; A. Peiro; A. Rodriguez

    2015-03-24

    Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we present the TREX-DM experiment, a low background Micromegas-based TPC for low-mass WIMP detection. Its main goal is the operation of an active detection mass $\\sim$0.300 kg, with an energy threshold below 0.4 keVee and fully built with previously selected radiopure materials. This article describes the actual setup, the first results of the comissioning in Ar+2\\%iC$_4$H$_{10}$ at 1.2 bar and the future updates for a possible physics run at the Canfranc Underground Laboratory in 2016. A first background model is also presented, based on Geant4 simulations and a muon/electron discrimination method. In a conservative scenario, TREX-DM could be sensitive to DAMA/LIBRA and other hints of positive WIMPs signals, with some space for improvement with a neutron/electron discrimination method or the use of other light gases.

  5. TREX-DM: a low background Micromegas-based TPC for low mass WIMP detection

    E-print Network

    Iguaz, F J; Aznar, F; Castel, J F; Cebrian, S; Dafni, T; Garcia, J A; Gomez, H; Gonzalez-Diaz, D; Irastorza, I G; Lagraba, A; Luzon, G; Peiro, A; Rodriguez, A

    2015-01-01

    Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we present the TREX-DM experiment, a low background Micromegas-based TPC for low-mass WIMP detection. Its main goal is the operation of an active detection mass $\\sim$0.300 kg, with an energy threshold below 0.4 keVee and fully built with previously selected radiopure materials. This article describes the actual setup, the first results of the comissioning in Ar+2\\%iC$_4$H$_{10}$ at 1.2 bar and the future updates for a possible physics run at the Canfranc Underground Laboratory in 2016. A first background model is also presented, based on Geant4 simulations and a muon/electron discrimination method. In a conservative scenario, TREX-DM could be sensitive to DAMA/LIBRA and other hints of positive WIMPs signals, with some space for improvement with a neutron/electron discrimination method or the use of other light gases.

  6. Design Constraints for a WIMP Dark Matter and pp Solar Neutrino Liquid Neon Scintillation Detector

    E-print Network

    M. G. Boulay; A. Hime; J. Lidgard

    2004-10-18

    Detailed Monte-Carlo simulations were used to evaluate the performance of a liquid neon scintillation detector for dark matter and low-energy solar neutrino interactions. A maximum-likelihood event vertex fitter including PMT time information was developed, which significantly improves position resolution over spatial-only algorithms, and substantially decreases the required detector size and achievable analysis energy threshold. The ultimate sensitivity to WIMP dark matter and the pp flux uncertainty are evaluated as a function of detector size. The dependence on the neon scintillation and PMT properties are evaluated. A 300 cm radius detector would allow a ~13 keV threshold, a pp flux uncertainty of ~1%, and limits on the spin-independent WIMP-nucleon cross-section of ~10^{-46} cm^2 for a 100 GeV WIMP, using commercially available PMTs. Detector response calibration and background requirements for a precision pp measurement are defined. Internal radioactivity requirements for uranium, thorium, and krypton are specified, and it is shown that the PMT data could be used for an in-situ calibration of the troublesome krypton-85. A set of measurements of neon scintillation properties and PMT characteristics are outlined which will be needed in order to evaluate feasibility and fully optimize the design of a neon-based detector.

  7. CMB Constraints On The Thermal WIMP Annihilation Cross Section

    E-print Network

    Steigman, Gary

    2015-01-01

    A thermal relic, often referred to as a weakly interacting massive particle (WIMP),is a particle produced during the early evolution of the Universe whose relic abundance (e.g., at present) depends only on its mass and its thermally averaged annihilation cross section (annihilation rate factor) sigma*v_ann. Late time WIMP annihilation has the potential to affect the cosmic microwave background (CMB) power spectrum. Current observational constraints on the absence of such effects provide bounds on the mass and the annihilation cross section of relic particles that may, but need not be dark matter candidates. For a WIMP that is a dark matter candidate, the CMB constraint sets an upper bound to the annihilation cross section, leading to a lower bound to their mass that depends on whether or not the WIMP is its own antiparticle. For a self-conjugate WIMP, m_min = 50f GeV, where f is an electromagnetic energy efficiency factor. For a non self-conjugate WIMP, the minimum mass is a factor of two larger. For a WIMP t...

  8. High sensitivity detection of NO2 employing off-axis integrated cavity output spectroscopy coupled with multiple line integrated spectroscopy

    NASA Astrophysics Data System (ADS)

    Rao, Gottipaty N.; Karpf, Andreas

    2011-05-01

    We report on the development of a new sensor for NO2 with ultrahigh sensitivity of detection. This has been accomplished by combining off-axis integrated cavity output spectroscopy (OA-ICOS) (which can provide large path lengths of the order of several km in a small volume cell) with multiple line integrated absorption spectroscopy (MLIAS) (where we integrate the absorption spectra over a large number of rotational-vibrational transitions of the molecular species to further improve the sensitivity). Employing an external cavity tunable quantum cascade laser operating in the 1601 - 1670 cm-1 range and a high-finesse optical cavity, the absorption spectra of NO2 over 100 transitions in the R-band have been recorded. From the observed linear relationship between the integrated absorption vs. concentration of NO2, we report an effective sensitivity of detection of 10 ppt for NO2. To the best of our knowledge, this is among the most sensitive levels of detection of NO2 to date. A sensitive sensor for the detection of NO2 will be helpful to monitor the ambient air quality, combustion emissions from the automobiles, power plants, aircraft and for the detection of nitrate based explosives (which are commonly used in improvised explosives (IEDs)). Additionally such a sensor would be valuable for the study of complex chemical reactions that undergo in the atmosphere resulting in the formation of photochemical smog, tropospheric ozone and acid rain.

  9. TREX-DM: a low-background Micromegas-based TPC for low-mass WIMP detection

    E-print Network

    F. J. Iguaz; J. G. Garza; F. Aznar; J. F. Castel; S. Cebrián; T. Dafni; J. A. García; I. G. Irastorza; A. Lagraba; G. Luzón; A. Peiró

    2015-12-04

    If Dark Matter is made of Weakly Interacting Massive Particles (WIMPs) with masses below 10-20 GeV, the corresponding nuclear recoils in mainstream WIMP experiments are of energies too close, or below, the experimental threshold. New detection techniques, focused on the use of light target nuclei together with low energy thresholds, are needed to get competitive sensitivity to the low-mass range of the WIMP parameter space. Gas Time Projection Chambers (TPCs) can be operated with a variety of target elements, and on account of the amplification in gas, very low thresholds are achievable. Recent advances in electronics and in novel radiopure TPC readouts, especially micro-mesh gas structure (Micromegas) are improving the scalability and low-background prospects of Micromegas-based TPCs. If we add their well-known tracking capabilities, they are a good detection option for the search of low-mass WIMPs. Here we present TREX-DM, a prototype built to test this concept. The detector is designed to host an active mass of $\\sim$0.300 kg of Ar at 10 bar, or alternatively $\\sim$0.160 kg of Ne at 10 bar, with an energy threshold below 0.4 keVee, and is fully built with radiopure materials. We will describe the detector in detail, as well as the results from the commissioning phase on surface, and the results from a preliminary background model. The anticipated sensitivity of this technique may go beyond current experimental limits for WIMPs of masses of 2-8 GeV.

  10. WIMP-Search Results from the Second CDMSlite Run

    SciTech Connect

    Agnese, R.

    2015-09-08

    The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Our results are presented from the second CDMSlite run with an exposure of 70 kg days, which reached an energy threshold for electron recoils as low as 56 eV. Furthermore, a fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded forWIMP masses between 1.6 and 5.5 GeV/c2.

  11. WIMP-Search Results from the Second CDMSlite Run

    E-print Network

    Agnese, R; Aramaki, T; Asai, M; Baker, W; Balakishiyeva, D; Barker, D; Thakur, R Basu; Bauer, D A; Billard, J; Borgland, A; Bowles, M A; Brink, P L; Bunker, R; Cabrera, B; Caldwell, D O; Calkins, R; Cerdeno, D G; Chagani, H; Chen, Y; Cooley, J; Cornell, B; Cushman, P; Daal, M; Di Stefano, P C F; Doughty, T; Esteban, L; Fallows, S; Figueroa-Feliciano, E; Ghaith, M; Godfrey, G L; Golwala, S R; Hall, J; Harris, H R; Hofer, T; Holmgren, D; Hsu, L; Huber, M E; Jardin, D; Jastram, A; Kamaev, O; Kara, B; Kelsey, M H; Kennedy, A; Leder, A; Loer, B; Asamar, E Lopez; Lukens, P; Mahapatra, R; Mandic, V; Mast, N; Mirabolfathi, N; Moffatt, R A; Mendoza, J D Morales; Oser, S M; Page, K; Page, W A; Partridge, R; Pepin, M; Phipps, A; Prasad, K; Pyle, M; Qiu, H; Rau, W; Redl, P; Reisetter, A; Ricci, Y; Roberts, A; Rogers, H E; Saab, T; Sadoulet, B; Sander, J; Schneck, K; Schnee, R W; Scorza, S; Serfass, B; Shank, B; Speller, D; Toback, D; Underwood, R; Upadhyayula, S; Villano, A N; Welliver, B; Wilson, J S; Wright, D H; Yellin, S; Yen, J J; Young, B A; Zhang, J

    2015-01-01

    The CDMS low ionization threshold experiment (CDMSlite) uses cryogenic germanium detectors operated at a relatively high bias voltage to amplify the phonon signal in the search for weakly interacting massive particles (WIMPs). Results are presented from the second CDMSlite run with an exposure of 70 kg days, which reached an energy threshold for electron recoils as low as 56 eV. A fiducialization cut reduces backgrounds below those previously reported by CDMSlite. New parameter space for the WIMP-nucleon spin-independent cross section is excluded for WIMP masses between 1.6 and 5.5 GeV/$c^2$.

  12. Comissioning of TREX-DM, a low background Micromegas-based Time Projection Chamber for low mass WIMP detection

    E-print Network

    Iguaz, F J; Aznar, F; Castel, J F; Cebrian, S; Dafni, T; Garcia, J A; Irastorza, I G; Lagraba, A; Luzon, G; Peiro, A

    2015-01-01

    Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we describe the TREX-DM experiment, a low background Micromegas-based Time Projection Chamber for low-mass WIMP detection. Its main goal is the operation of an active detection mass $\\sim$0.3 kg, with an energy threshold below 0.4~keVee and fully built with previously selected radiopure materials. This work focuses on the commissioning of the actual setup situated in a laboratory on surface. A preliminary background model of the experiment is also presented, based on Geant4 simulations and two discrimination methods: a conservative muon/electron and one based on a $^{252}$Cf source. Based on this model, TREX-DM could be competitive in the search for low mass WIMPs and, in particular, it could be sensitive to the WIMP interpretation of the DAMA/LIBRA hint.

  13. Comissioning of TREX-DM, a low background Micromegas-based Time Projection Chamber for low mass WIMP detection

    E-print Network

    F. J. Iguaz; J. G. Garza; F. Aznar; J. F. Castel; S. Cebrian; T. Dafni; J. A. Garcia; I. G. Irastorza; A. Lagraba; G. Luzon; A. Peiro

    2015-09-07

    Dark Matter experiments are recently focusing their detection techniques in low-mass WIMPs, which requires the use of light elements and low energy threshold. In this context, we describe the TREX-DM experiment, a low background Micromegas-based Time Projection Chamber for low-mass WIMP detection. Its main goal is the operation of an active detection mass $\\sim$0.3 kg, with an energy threshold below 0.4~keVee and fully built with previously selected radiopure materials. This work focuses on the commissioning of the actual setup situated in a laboratory on surface. A preliminary background model of the experiment is also presented, based on Geant4 simulations and two discrimination methods: a conservative muon/electron and one based on a $^{252}$Cf source. Based on this model, TREX-DM could be competitive in the search for low mass WIMPs and, in particular, it could be sensitive to the WIMP interpretation of the DAMA/LIBRA hint.

  14. TREX-DM: a low-background Micromegas-based TPC for low-mass WIMP detection

    E-print Network

    Iguaz, F J; Aznar, F; Castel, J F; Cebrián, S; Dafni, T; García, J A; Irastorza, I G; Lagraba, A; Luzón, G; Peiró, A

    2015-01-01

    If Dark Matter is made of Weakly Interacting Massive Particles (WIMPs) with masses below 10-20 GeV, the corresponding nuclear recoils in mainstream WIMP experiments are of energies too close, or below, the experimental threshold. New detection techniques, focused on the use of light target nuclei together with low energy thresholds, are needed to get competitive sensitivity to the low-mass range of the WIMP parameter space. Gas Time Projection Chambers (TPCs) can be operated with a variety of target elements, and on account of the amplification in gas, very low thresholds are achievable. Recent advances in electronics and in novel radiopure TPC readouts, especially micro-mesh gas structure (Micromegas) are improving the scalability and low-background prospects of Micromegas-based TPCs. If we add their well-known tracking capabilities, they are a good detection option for the search of low-mass WIMPs. Here we present TREX-DM, a prototype built to test this concept. The detector is designed to host an active ma...

  15. X-ray emission-line spectra of photoionized plasmas - Density sensitivity of the Fe L-shell series

    NASA Technical Reports Server (NTRS)

    Liedahl, Duane A.; Kahn, Steven M.; Osterheld, Albert L.; Goldstein, William H.

    1992-01-01

    The circumsource environments of accretion-powered X-ray sources are likely to support relatively dense (greater than 10 exp 11/cu cm) photoionized X-ray emission-line regions. The Fe L-shell ions provide a versatile class of plasma diagnostics in this regime, their multielectron structures resulting in diverse spectral phenomena. Attention is given to the spectral response of Fe L-shell ions to variations in electron density over the range 10 exp 11 to 10 exp 16/cu cm. It is found that density-sensitive line ratios exist in the wavelength interval 12-17 A for the ions Fe XVII-XXI. The prominent role of radiative recombination in the population kinetics distinguishes the density-sensitive Fe lines in photoionized plasmas from those which operate in coronal equilibrium plasmas. The results of detailed atomic modeling of these ions are presented and applications to spectroscopic observations of accretion-driven X-ray sources are discussed.

  16. DIFFERENTIAL CYTOTOXIC SENSITIVITY IN MOUSE AND HUMAN CELL LINES EXPOSED TO ORGANOPHOSPHATE INSECTICIDES

    EPA Science Inventory

    Cell lines were used to examine the differential interspecies response (i.e., species selectivity) to organophosphates (OPs). aseline activities of the major target esterase i.e., cholinesterase (ChE), carboxylesterase (CbxE), neurotoxic esterase (NTE) were assayed in mouse and v...

  17. Environmental sensitivity differs between rabbit lines selected for reproductive intensity and longevity.

    PubMed

    Savietto, D; Cervera, C; Blas, E; Baselga, M; Larsen, T; Friggens, N C; Pascual, J J

    2013-12-01

    To better understand the mechanisms that allow some animals to sustain their productive effort in harsh environmental conditions, rabbit does from two selection lines (LP and V) were housed in normal (NC), nutritional (NF) or heat (HC) challenging environmental conditions from first to third partum. The LP line (n=85) was founded on reproductive longevity criteria by selecting does from commercial farms that had a minimum of 25 partum with more than 7.5 kits born alive per parity. Line V (n=79) was constituted from four specialised maternal lines into a composite synthetic line and then selected by litter size at weaning for 36 generations. Female rabbits in NC and NF environments were housed at normal room temperature (18°C to 24°C) and fed with control [11.6 MJ digestible energy (DE)/kg dry matter (DM)] or low-energy diets (9.1 MJ DE/kg DM). HC does were housed at high room temperatures (25°C to 35°C) and fed the control diet. Female rabbits in the HC and NF environments ingested 11.5% and 6% less DE than NC does, respectively (P<0.05). These differences between environments occurred in both lines, with the differences being higher for LP than for V does (+6%; P<0.05). Milk yield responses followed those of energy intake also being higher for LP does (+21.3 g/day; P<0.05). The environmental conditions did not affect the perirenal fat thickness (PFT), but a genotype by environment interaction was observed. In NC and HC, the PFT was higher for line V (+0.23 and +0.35 mm, respectively; P<0.05) than for LP does, but this was not the case at NF (-0.01 mm). Moreover, the PFT evolution was different between them. In the NC environment, LP does used the accreted PFT in late lactation (-0.29 mm), whereas V does did not (-0.08 mm). Conversely, in the HC environment, LP does showed a flat PFT evolution in late lactation, whereas V does accumulated PFT. In the NF environment, LP and V does had a similar PFT evolution. There was also a litter size reduction for V does of -2.59 kits total born in HC and -1.78 kits total born in NF environments, whereas this was not observed for LP does. The results for LP does indicate a direct use of DE ingested for reproduction with little PFT change, whereas V does actively use the PFT reserves for reproduction. PMID:24237674

  18. Hybridization approach to in-line and off-axis (electron) holography for superior resolution and phase sensitivity.

    PubMed

    Ozsoy-Keskinbora, C; Boothroyd, C B; Dunin-Borkowski, R E; van Aken, P A; Koch, C T

    2014-01-01

    Holography--originally developed for correcting spherical aberration in transmission electron microscopes--is now used in a wide range of disciplines that involve the propagation of waves, including light optics, electron microscopy, acoustics and seismology. In electron microscopy, the two primary modes of holography are Gabor's original in-line setup and an off-axis approach that was developed subsequently. These two techniques are highly complementary, offering superior phase sensitivity at high and low spatial resolution, respectively. All previous investigations have focused on improving each method individually. Here, we show how the two approaches can be combined in a synergetic fashion to provide phase information with excellent sensitivity across all spatial frequencies, low noise and an efficient use of electron dose. The principle is also expected to be widely to applications of holography in light optics, X-ray optics, acoustics, ultra-sound, terahertz imaging, etc. PMID:25387480

  19. Hybridization approach to in-line and off-axis (electron) holography for superior resolution and phase sensitivity

    PubMed Central

    Ozsoy-Keskinbora, C.; Boothroyd, C. B.; Dunin-Borkowski, R. E.; van Aken, P. A.; Koch, C. T.

    2014-01-01

    Holography - originally developed for correcting spherical aberration in transmission electron microscopes - is now used in a wide range of disciplines that involve the propagation of waves, including light optics, electron microscopy, acoustics and seismology. In electron microscopy, the two primary modes of holography are Gabor's original in-line setup and an off-axis approach that was developed subsequently. These two techniques are highly complementary, offering superior phase sensitivity at high and low spatial resolution, respectively. All previous investigations have focused on improving each method individually. Here, we show how the two approaches can be combined in a synergetic fashion to provide phase information with excellent sensitivity across all spatial frequencies, low noise and an efficient use of electron dose. The principle is also expected to be widely to applications of holography in light optics, X-ray optics, acoustics, ultra-sound, terahertz imaging, etc. PMID:25387480

  20. Integrated Cantilever-Based Flow Sensors with Tunable Sensitivity for In-Line Monitoring of Flow Fluctuations in Microfluidic Systems

    PubMed Central

    Noeth, Nadine; Keller, Stephan Sylvest; Boisen, Anja

    2014-01-01

    For devices such as bio-/chemical sensors in microfluidic systems, flow fluctuations result in noise in the sensor output. Here, we demonstrate in-line monitoring of flow fluctuations with a cantilever-like sensor integrated in a microfluidic channel. The cantilevers are fabricated in different materials (SU-8 and SiN) and with different thicknesses. The integration of arrays of holes with different hole size and number of holes allows the modification of device sensitivity, theoretical detection limit and measurement range. For an average flow in the microliter range, the cantilever deflection is directly proportional to the flow rate fluctuations in the microfluidic channel. The SiN cantilevers show a detection limit below 1 nL/min and the thinnest SU-8 cantilevers a detection limit below 5 nL/min. Finally, the sensor is applied for in-line monitoring of flow fluctuations generated by external pumps connected to the microfluidic system. PMID:24366179

  1. On the sensitivity of HeI singlet lines to the FeIV model atom in O stars

    E-print Network

    F. Najarro; D. J. Hillier; J. Puls; T. Lanz; F. Martins

    2006-05-08

    Recent calculations and analyses of O star spectra have revealed discrepancies between theory and observations, and between different theoretical calculations, for the strength of optical HeI singlet transitions.We investigate the source of these discrepancies. Using a non-LTE radiative transfer code we have undertaken detailed test calculations for a range of O star properties. Our principal test model has parameters similar to those of the O9V star, 10 Lac. We show that the discrepancies arise from uncertainties in the radiation field in the HeI resonance transition near 584Angs. The radiation field at 584Angs. is influenced by model assumptions, such as the treatment of line-blanketing and the adopted turbulent velocity, and by the FeIV atomic data. It isshown that two FeIV transitions near 584Angs can have a substantial influence on the strength of the HeI singlet transitions. Because of the difficulty of modeling the HeI singlet lines, particularly in stars with solar metalicity, the HeI triplet lines should be preferred in spectral analyses. These lines are much less sensitive to model assumptions.

  2. Chromatin status of apoptosis genes correlates with sensitivity to chemo-, immune- and radiation therapy in colorectal cancer cell lines.

    PubMed

    Benard, Anne; Janssen, Connie M; van den Elsen, Peter J; van Eggermond, Marja C J A; Hoon, Dave S B; van de Velde, Cornelis J H; Kuppen, Peter J K

    2014-12-01

    The apoptosis pathway of programmed cell death is frequently deregulated in cancer. An intact apoptosis pathway is required for proper response to anti-cancer treatment. We investigated the chromatin status of key apoptosis genes in the apoptosis pathway in colorectal cancer cell lines in relation to apoptosis induced by chemo-, immune- or radiation therapy. Using chromatin immunoprecipitation (ChIP), we measured the presence of transcription-activating histone modifications H3Ac and H3K4me3 and silencing modifications H3K9me3 and H3K27me3 at the gene promoter regions of key apoptosis genes Bax, Bcl2, Caspase-9, Fas (CD95) and p53. Cell lines DLD1, SW620, Colo320, Caco2, Lovo and HT29 were treated with cisplatin, anti-Fas or radiation. The apoptotic response was measured by flow cytometry using propidium iodide and annexin V-FITC. The chromatin status of the apoptosis genes reflected the activation status of the intrinsic (Bax, Bcl2, Caspase-9 and p53) and extrinsic (Fas) pathways. An active intrinsic apoptotic pathway corresponded to sensitivity to cisplatin and radiation treatment of cell lines DLD1, SW620 and Colo320. An active Fas promoter corresponded to an active extrinsic apoptotic pathway in cell line DLD1. mRNA expression data correlated with the chromatin status of the apoptosis genes as measured by ChIP. In conclusion, the results presented in this study indicate that the balance between activating and silencing histone modifications, reflecting the chromatin status of apoptosis genes, can be used to predict the response of tumor cells to different anti-cancer therapies and could provide a novel target to sensitize tumors to obtain adequate treatment responses. PMID:25292014

  3. Understanding WIMP-baryon interactions with direct detection: a roadmap

    SciTech Connect

    Gluscevic, Vera; Peter, Annika H.G. E-mail: apeter@physics.osu.edu

    2014-09-01

    We study prospects of dark-matter direct-detection searches for probing non-relativistic effective theory for WIMP-baryon scattering. We simulate a large set of noisy recoil-energy spectra for different scattering scenarios (beyond the standard momentum-independent contact interaction), for Generation 2 and futuristic experiments. We analyze these simulations and quantify the probability of successfully identifying the operator governing the scattering, if a WIMP signal is observed. We find that the success rate depends on a combination of factors: the WIMP mass, the mediator mass, the type of interaction, and the experimental energy window. For example, for a 20 GeV WIMP, Generation 2 is only likely to identify the right operator if the interaction is Coulomb-like, and is unlikely to do so in any other case. For a WIMP with a mass of 200 GeV or higher, success is almost guaranteed. We also find that, regardless of the scattering model and the WIMP parameters, a single Generation 2 experiment is unlikely to successfully discern the momentum dependence of the underlying operator on its own, but prospects improve drastically when experiments with different target materials and energy windows are analyzed jointly. Furthermore, we examine the quality of parameter estimation and degeneracies in the multi-dimensional parameter space of the effective theory. We find in particular that the resulting WIMP mass estimates can be severely biased if data are analyzed assuming the standard (momentum-independent) operator while the actual operator has momentum-dependence. Finally, we evaluate the ultimate reach of direct detection, finding that the prospects for successful operator selection prior to reaching the irreducible backgrounds are excellent, if the signal is just below the current limits, but slim if Generation 2 does not report WIMP detection.

  4. Development of Gaseous Tracking Devices for the Search of WIMPs

    E-print Network

    H. Sekiya; K. Hattori; S. Kabuki; H. Kubo; K. Miuchi; T. Nagayoshi; H. Nishimura; Y. Okada; R. Orito; A. Takada; A. Takeda; T. Tanimori; K. Ueno

    2006-02-14

    The Time Projection Chamber (TPC) has been recognized as a potentially powerful detector for the search of WIMPs by measuring the directions of nuclear recoils, in which the most convincing signature of WIMPs, caused by the Earth's motion around the Galaxy, appears. We report on the first results of a performance study of the neutron exposure of our prototype micro-TPC with Ar-C$_2$H$_6$ (90:10) and CF$_4$ gas of 150 Torr.

  5. Model-independent WIMP Searches at the ILC

    E-print Network

    C. Bartels; J. List

    2007-09-17

    We investigate the possibility to detect WIMPs at the ILC in a model-independent way using events with single photons. The study is done with a full detector simulation of the LDC detector and MarlinReco. It turns out that WIMPs are observable this way at the ILC if their coupling to electrons is not too small. Beam polarisation can increase the accessible phase space significantly.

  6. Application of Time Projection Chambers with GEMs and Pixels to WIMP Searches and Fast Neutron Detection

    E-print Network

    Jared Yamaoka; Haolu Feng; Maurice Garcia-Sciveres; Igal Jaegle; John Kadyk; Young Nguyen; Marc Rosen; Steven Ross; Thomas Thorpe; Sven Vahsen

    2012-06-11

    We present work on the detection of neutral particles via nuclear recoils in gas-filled Time Projection Chambers (TPCs). We employ Gas Electron Multipliers (GEMs) to amplify the signal and silicon pixel electronics to detect the avalanche charge. These technologies allow ionization in the target gas to be detected with low noise, improved position and time resolution, and high efficiency. We review experimental results obtained in previous years, and report on ongoing simulation studies and construction of the first prototype at the University of Hawaii. We also present prospects of using such detectors to perform direction-sensitive searches for WIMP dark matter and fast neutron from fissionable material.

  7. Fission Product Gamma-Ray Line Pairs Sensitive to Fissile Material and Neutron Energy

    SciTech Connect

    Marrs, R E; Norman, E B; Burke, J T; Macri, R A; Shugart, H A; Browne, E; Smith, A R

    2007-11-15

    The beta-delayed gamma-ray spectra from the fission of {sup 235}U, {sup 238}U, and {sup 239}Pu by thermal and near-14-MeV neutrons have been measured for delay times ranging from 1 minute to 14 hours. Spectra at all delay times contain sets of prominent gamma-ray lines with intensity ratios that identify the fissile material and distinguish between fission induced by low-energy or high-energy neutrons.

  8. Response of sensitive human ataxia and resistant T-1 cell lines to accelerated heavy ions

    SciTech Connect

    Tobias, C.A.; Blakely, E.A.; Chang, P.Y.; Lommel, L.; Roots, R.

    1983-07-01

    The radiation dose responses of fibroblast from a patient with Ataxia telangiectasis (AT-2SF) and an established line of human T-1 cells were studied. Nearly monoenergetic accelerated neon and argon ions were used at the Berkeley Bevalac with various residual range values. The LET of the particles varied from 30 keV/..mu..m to over 1000 keV/..mu..m. All Ataxia survival curves were exponential functions of the dose. Their radiosensitivity reached peak values at 100 to 200 keV/..mu..m. Human T-1 cells have effective sublethal damage repair as has been evidenced by split dose experiments, and they are much more resistant to low LET than to high LET radiation. The repair-misrepair model has been used to interpret these results. We have obtained mathematical expressions that describe the cross sections and inactivation coefficients for both human cell lines as a function of the LET and the type of particle used. The results suggest either that high-LET particles induce a greater number of radiolesions per track or that heavy-ions at high LET induce lesions that kill cells more effectively and that are different from those produced at low LET. We assume that the lesions induced in T-1 and Ataxia cells are qualitatively similar and that each cell line attempts to repair these lesions. The result in most irradiated Ataxia cells, however, is either lethal misrepair or incomplete repair leading to cell death. 63 references, 10 figures, 1 table.

  9. Determining the WIMP mass from a single direct detection experiment, a more detailed study

    E-print Network

    Anne M. Green

    2008-06-04

    The energy spectrum of nuclear recoils in Weakly Interacting Massive Particle (WIMP) direct detection experiments depends on the underlying WIMP mass. We study how the accuracy with which the WIMP mass could be determined by a single direct detection experiment depends on the detector configuration and the WIMP properties. We investigate the effects of varying the underlying WIMP mass and cross-section, the detector target nucleus, exposure, energy threshold and maximum energy, the local circular speed and the background event rate and spectrum. The number of events observed is directly proportional to both the exposure and the cross-section, therefore these quantities have the greatest bearing on the accuracy of the WIMP mass determination. The relative capabilities of different detectors to determine the WIMP mass depend not only on the WIMP and target masses, but also on their energy thresholds. We find that the rapid decrease of the nuclear form factor with increasing momentum transfer which occurs for heavy nuclei, means that heavy nuclei will not necessarily be able to measure the mass of heavy WIMPs more accurately. Uncertainty in the local circular speed and non-negligible background would both lead to systematic errors in the WIMP mass determination. With a single detector it will be difficult to disentangle a WIMP signal (and the WIMP mass) from background if the background spectrum has a similar shape to the WIMP spectrum (i.e. exponential background, or flat background and a heavy WIMP).

  10. Directional recoil rate for direct detection of WIMPs

    NASA Astrophysics Data System (ADS)

    Alenazi, Moqbil; Gondolo, Paolo

    2007-10-01

    The problem of directional direct detection of weakly interacting massive particles (WIMPs) dark matter (DM) is investigated. We compute, analytically and numerically, the directional differential recoil rate dRd? of recoiled target nuclei hit by WIMPs in direct detection experiments in terms of the angle ?, which is the angle between the reference direction and the recoil direction. While the analytic method is for fixed reference direction and Gaussian distribution of WIMPs, the numeric method is a general method. The two methods give the same results. We apply the numeric method to various Maxwellian distributions including; a stream of WIMPs, the standard dark halo, streams of WIMPs from Sikivie's late-infall (SLI) halo model, and streams with anisotropic velocity distributions. We show the results as distributions of the nuclei's directional differential recoil rate dRd? as a function of ?. We introduce a `folded' directional differential recoil rate dRd|?| to overcome the difficulty of head-tail discrimination in some WIMP's direct detectors. We conclude that dRd|?| can be helpful in recognizing cases of anisotropic streams and isotropic standard dark halo but not in the case of SLI streams.

  11. WIMP-nucleus scattering in chiral effective theory

    E-print Network

    Vincenzo Cirigliano; Michael L. Graesser; Grigory Ovanesyan

    2012-05-11

    We discuss long-distance QCD corrections to the WIMP-nucleon(s) interactions in the framework of chiral effective theory. For scalar-mediated WIMP-quark interactions, we calculate all the next-to-leading-order corrections to the WIMP-nucleus elastic cross-section, including two-nucleon amplitudes and recoil-energy dependent shifts to the single-nucleon scalar form factors. As a consequence, the scalar-mediated WIMP-nucleus cross-section cannot be parameterized in terms of just two quantities, namely the neutron and proton scalar form factors at zero momentum transfer, but additional parameters appear, depending on the short-distance WIMP-quark interaction. Moreover, multiplicative factorization of the cross-section into particle, nuclear and astro-particle parts is violated. In practice, while the new effects are of the natural size expected by chiral power counting, they become very important in those regions of parameter space where the leading order WIMP-nucleus amplitude is suppressed, including the so-called "isospin-violating dark matter" regime. In these regions of parameter space we find order-of-magnitude corrections to the total scattering rates and qualitative changes to the shape of recoil spectra.

  12. Heavy WIMP through Higgs portal at the LHC

    NASA Astrophysics Data System (ADS)

    Endo, Motoi; Takaesu, Yoshitaro

    2015-04-01

    The LHC constraints on Higgs-portal WIMPs are studied. Scalar, vector and anti-symmetric tensor fields are considered. They are assumed to be heavier than a half of the Higgs boson mass. We investigate 8 TeV LHC results on signatures of the vector boson fusion, mono-jet and associated production of the Z boson, which proceed via virtual exchange of the Higgs boson. We show that the vector boson fusion channel gives the most stringent constraints on Higgs-portal interactions for all the WIMP models investigated here. The upper limits on vector and tensor Higgs-portal couplings can be 0.43 and 0.16 for the WIMP mass of 65 GeV, respectively. However, they are rapidly weakened for heavier WIMP masses, allowing O (1) couplings for masses heavier than ? 100 GeV. Constraints for scalar WIMPs are very weak. Prospects of the 14 TeV LHC are also discussed. We show that the constraints on the tensor and vector couplings would be improved by a factor of ? 1.5- 2, depending on the search channels. It would be still challenging to constrain scalar WIMPs.

  13. Search for gamma-ray spectral lines with the Fermi Large Area Telescope and dark matter implications

    NASA Astrophysics Data System (ADS)

    Ackermann, M.; Ajello, M.; Albert, A.; Allafort, A.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Bissaldi, E.; Bloom, E. D.; Bonamente, E.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Charles, E.; Chaves, R. C. G.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Digel, S. W.; Di Venere, L.; Drell, P. S.; Drlica-Wagner, A.; Essig, R.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Hayashida, M.; Hill, A. B.; Horan, D.; Hou, X.; Hughes, R. E.; Inoue, Y.; Izaguirre, E.; Jogler, T.; Kamae, T.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Malyshev, D.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, T.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Romani, R. W.; Sánchez-Conde, M.; Schulz, A.; Sgrò, C.; Siegal-Gaskins, J.; Siskind, E. J.; Snyder, A.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Takahashi, H.; Thayer, J. G.; Thayer, J. B.; Tibaldo, L.; Tinivella, M.; Tosti, G.; Troja, E.; Uchiyama, Y.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Winer, B. L.; Wood, K. S.; Wood, M.; Yang, Z.; Zaharijas, G.; Zimmer, S.

    2013-10-01

    Weakly interacting massive particles (WIMPs) are a theoretical class of particles that are excellent dark matter candidates. WIMP annihilation or decay may produce essentially monochromatic ? rays detectable by the Fermi Large Area Telescope (LAT) against the astrophysical ?-ray emission of the Galaxy. We have searched for spectral lines in the energy range 5-300 GeV using 3.7 years of data, reprocessed with updated instrument calibrations and an improved energy dispersion model compared to the previous Fermi-LAT Collaboration line searches. We searched in five regions selected to optimize sensitivity to different theoretically motivated dark matter density distributions. We did not find any globally significant lines in our a priori search regions and present 95% confidence limits for annihilation cross sections of self-conjugate WIMPs and decay lifetimes. Our most significant fit occurred at 133 GeV in our smallest search region and had a local significance of 3.3 standard deviations, which translates to a global significance of 1.5 standard deviations. We discuss potential systematic effects in this search, and examine the feature at 133 GeV in detail. We find that the use both of reprocessed data and of additional information in the energy dispersion model contributes to the reduction in significance of the linelike feature near 130 GeV relative to significances reported in other works. We also find that the feature is narrower than the LAT energy resolution at the level of 2 to 3 standard deviations, which somewhat disfavors the interpretation of the 133 GeV feature as a real WIMP signal.

  14. Photographic but not line-drawn faces show early perceptual neural sensitivity to eye gaze direction

    PubMed Central

    Rossi, Alejandra; Parada, Francisco J.; Latinus, Marianne; Puce, Aina

    2015-01-01

    Our brains readily decode facial movements and changes in social attention, reflected in earlier and larger N170 event-related potentials (ERPs) to viewing gaze aversions vs. direct gaze in real faces (Puce et al., 2000). In contrast, gaze aversions in line-drawn faces do not produce these N170 differences (Rossi et al., 2014), suggesting that physical stimulus properties or experimental context may drive these effects. Here we investigated the role of stimulus-induced context on neurophysiological responses to dynamic gaze. Sixteen healthy adults viewed line-drawn and real faces, with dynamic eye aversion and direct gaze transitions, and control stimuli (scrambled arrays and checkerboards) while continuous electroencephalographic (EEG) activity was recorded. EEG data from 2 temporo-occipital clusters of 9 electrodes in each hemisphere where N170 activity is known to be maximal were selected for analysis. N170 peak amplitude and latency, and temporal dynamics from Event-Related Spectral Perturbations (ERSPs) were measured in 16 healthy subjects. Real faces generated larger N170s for averted vs. direct gaze motion, however, N170s to real and direct gaze were as large as those to respective controls. N170 amplitude did not differ across line-drawn gaze changes. Overall, bilateral mean gamma power changes for faces relative to control stimuli occurred between 150–350 ms, potentially reflecting signal detection of facial motion. Our data indicate that experimental context does not drive N170 differences to viewed gaze changes. Low-level stimulus properties, such as the high sclera/iris contrast change in real eyes likely drive the N170 changes to viewed aversive movements. PMID:25914636

  15. A Neutron Sensitive Microchannel Plate Detector with Cross Delay Line Readout

    SciTech Connect

    Berry, Kevin D.; Bilheux, Hassina Z.; Crow, Lowell; Diawara, Yacouba; Feller, W. Bruce; Iverson, Erik B.; Martin, Adrian; Robertson, J. Lee

    2012-01-01

    Microchannel plates containing neutron absorbing elements such as boron and gadolinium in the bulk glass are used as the sensing element in high spatial resolution, high rate neutron imaging systems. In this paper we describe one such device, using both 10B and natural Gd, which employs cross delay line signal readout, with time-of-flight capability. This detector has a measured spatial resolution under 40 m FWHM, thermal neutron efficiency of 19%, and has recorded rates in excess of 500 kHz. A physical and functional description is presented, followed by a discussion of measurements of detector performance and a brief survey of some practical applications.

  16. FIRST 5 TOWER WIMP-SEARCH RESULTS FROM THE CRYOGENIC DARK MATTER SEARCH WITH IMPROVED UNDERSTANDING OF

    E-print Network

    California at Berkeley, University of

    FIRST 5 TOWER WIMP-SEARCH RESULTS FROM THE CRYOGENIC DARK MATTER SEARCH WITH IMPROVED UNDERSTANDING particle candidates . . . . . . . . . . . . . . . . . . . . . 42 1.8.1 WIMP Candidates From Particle Physics: SUSY . . . . . . . 44 1.8.2 Expected WIMP relic density . . . . . . . . . . . . . . . . . . 46 1

  17. NQR Line Broadening Due to Crystal Lattice Imperfections and Its Relationship to Shock Sensitivity

    NASA Astrophysics Data System (ADS)

    Caulder, S. M.; Buess, M. L.; Garroway, A. N.; Miller, P. J.

    2004-07-01

    The hydrodynamic hot spot model is used to explain the difference between shock sensitive and shock insensitive explosives. Among the major factors that influence the shock sensitivity of energetic compounds are the quality and particle size of the energetic crystals used to formulate the cast plastic bonded explosive. As do all energetic compounds, RDX and HMX exhibit internal crystal defects the magnitude and type of which depend on the manufacturing process used to synthesize and re-crystallize the energetic compound. Nuclear Quadrupole Resonance (NQR) spectroscopy was used to determine the crystal quality of RDX, HMX and CL-20 obtained from various manufacturers. The NQR experimental results are discussed. Cast plastic bonded explosives were made using the RDX and HMX obtained from the various manufacturers and subsequently subjected to the NOL large-scale gap test (LSGT). The results of the LSGT are discussed and correlated with the NQR results. A relationship between the crystal defect density and shock initiation pressure of the plastic bonded explosive is developed and discussed.

  18. Lethal and mutagenic effects of 4-nitroquinoline 1-oxide in uv-sensitive and wild-type CHO cell lines

    SciTech Connect

    Tincknell, B.P.

    1982-09-01

    A wild-type Chinese hamster ovary cell line (CHO-9) and its uv-sensitive subclone (43-3B) have been used in characterizing the lethal and mutagenic effects of the chemical carcinogen, 4-nitroquinoline 1-oxide (4NQO). Cell survival as a function of 4NQO dose was determined for exponential and growth arrested populations of both cell lines. During exponential growth, 43-3B was 3.7 times more sensitive than CHO-9 (based on the ratio of the D/sub 0/ doses) to induced reproductive death by 4NQO. for both cell lines, cells treated during growth arrest survived at close to control values. Expression time for resistance at three loci, 6-thioguanine resistance (6TG/sup r/), ouabain resistance (OUA/sup R/) and resistance to diptheria toxin (DT/sup r/), was determined and was complete for all three markers by the eighth day post-treatment. Dose response curves for these markers measured on Day 8 were linear in CHO-9 over the range of doses tested. Preliminary results for induction of 6TG/sup r/ in 43-3B show the subclone to be hypermutable on a per dose basis but hypomutable at equal levels of survival (2.6 times less mutable compared at D/sub 0/). Studies of survival and mutation in synchronous cells were undertaken for CHO-9. A pronounced cell cycle effect was seen with lowest survival during late G1. Mutation induction was highest during G1; the degree and pattern of cycle variation depending on the locus examined.

  19. Increased sensitivity to gemcitabine of P-glycoprotein and multidrug resistance-associated protein-overexpressing human cancer cell lines.

    PubMed

    Bergman, A M; Pinedo, H M; Talianidis, I; Veerman, G; Loves, W J P; van der Wilt, C L; Peters, G J

    2003-06-16

    Gemcitabine (2',2'-difluorodeoxycytidine) is a deoxycytidine analogue that is activated by deoxycytidine kinase (dCK) to its monophosphate and subsequently to its triphosphate dFdCTP, which is incorporated into both RNA and DNA, leading to DNA damage. Multidrug resistance (MDR) is characterised by an overexpression of the membrane efflux pumps P-glycoprotein (P-gP) or multidrug resistance-associated protein (MRP). Gemcitabine was tested against human melanoma, non-small-cell lung cancer, small-cell lung cancer, epidermoid carcinoma and ovarian cancer cells with an MDR phenotype as a result of selection by drug exposure or by transfection with the mdr1 gene. These cell lines were nine- to 72-fold more sensitive to gemcitabine than their parental cell lines. The doxorubicin-resistant cells 2R120 (MRP1) and 2R160 (P-gP) were nine- and 28-fold more sensitive to gemcitabine than their parental SW1573 cells, respectively (P<0.01), which was completely reverted by 25 micro M verapamil. In 2R120 and 2R160 cells, dCK activities were seven- and four-fold higher than in SW1573, respectively, which was associated with an increased dCK mRNA and dCK protein. Inactivation by deoxycytidine deaminase was 2.9- and 2.2-fold decreased in 2R120 and 2R160, respectively. dFdCTP accumulation was similar in SW1573 and its MDR variants after 24 h exposure to 0.1 micro M gemcitabine, but dFdCTP was retained longer in 2R120 (P<0.001) and 2R160 (P<0.003) cells. 2R120 and 2R160 cells also incorporated four- and six-fold more [(3)H]gemcitabine into DNA (P<0.05), respectively. P-glycoprotein and MRP1 overexpression possibly caused a cellular stress resulting in increased gemcitabine metabolism and sensitivity, while reversal of collateral gemcitabine sensitivity by verapamil also suggests a direct relation between the presence of membrane efflux pumps and gemcitabine sensitivity. PMID:12799644

  20. Protein Profiles Reveal Diverse Responsive Signaling Pathways in Kernels of Two Maize Inbred Lines with Contrasting Drought Sensitivity

    PubMed Central

    Yang, Liming; Jiang, Tingbo; Fountain, Jake C.; Scully, Brian T.; Lee, Robert D.; Kemerait, Robert C.; Chen, Sixue; Guo, Baozhu

    2014-01-01

    Drought stress is a major factor that contributes to disease susceptibility and yield loss in agricultural crops. To identify drought responsive proteins and explore metabolic pathways involved in maize tolerance to drought stress, two maize lines (B73 and Lo964) with contrasting drought sensitivity were examined. The treatments of drought and well water were applied at 14 days after pollination (DAP), and protein profiles were investigated in developing kernels (35 DAP) using iTRAQ (isobaric tags for relative and absolute quantitation). Proteomic analysis showed that 70 and 36 proteins were significantly altered in their expression under drought treatments in B73 and Lo964, respectively. The numbers and levels of differentially expressed proteins were generally higher in the sensitive genotype, B73, implying an increased sensitivity to drought given the function of the observed differentially expressed proteins, such as redox homeostasis, cell rescue/defense, hormone regulation and protein biosynthesis and degradation. Lo964 possessed a more stable status with fewer differentially expressed proteins. However, B73 seems to rapidly initiate signaling pathways in response to drought through adjusting diverse defense pathways. These changes in protein expression allow for the production of a drought stress-responsive network in maize kernels. PMID:25334062

  1. Mycoplasma hyorhinis-Contaminated Cell Lines Activate Primary Innate Immune Cells via a Protease-Sensitive Factor

    PubMed Central

    Heidegger, Simon; Jarosch, Alexander; Schmickl, Martina; Endres, Stefan; Bourquin, Carole; Hotz, Christian

    2015-01-01

    Mycoplasma are a frequent and occult contaminant of cell cultures, whereby these prokaryotic organisms can modify many aspects of cell physiology, rendering experiments that are conducted with such contaminated cells problematic. Chronic Mycoplasma contamination in human monocytic cells lines has been associated with suppressed Toll-like receptor (TLR) function. In contrast, we show here that components derived from a Mycoplasma hyorhinis-infected cell line can activate innate immunity in non-infected primary immune cells. Release of pro-inflammatory cytokines such as IL-6 by dendritic cells in response to Mycoplasma hyorhinis-infected cell components was critically dependent on the adapter protein MyD88 but only partially on TLR2. Unlike canonical TLR2 signaling that is triggered in response to the detection of Mycoplasma infection, innate immune activation by components of Mycoplasma-infected cells was inhibited by chloroquine treatment and sensitive to protease treatment. We further show that in plasmacytoid dendritic cells, soluble factors from Mycoplasma hyorhinis-infected cells induce the production of large amounts of IFN-?. We conclude that Mycoplasma hyorhinis-infected cell lines release protein factors that can potently activate co-cultured innate immune cells via a previously unrecognized mechanism, thus limiting the validity of such co-culture experiments. PMID:26565413

  2. Second-line options for refractory steroid-sensitive and -resistant nephrotic syndrome.

    PubMed

    Oh, Jun; Kemper, Markus J

    2010-07-01

    Although initially, many children with idiopathic nephrotic syndrome respond to steroid therapy, a repeated course for patients with relapses often causes significant steroid toxicity. Patients with frequent relapses or steroid dependency thus require alternative treatment, and so far, cyclophosphamide or levamisole have been regarded as first-choice options, although the latter is no longer available in many countries. Data are accumulating that mycophenolic acid may be an alternative for these patients. Calcineurin inhibitors (cyclosporine A or tacrolimus) are usually effective and are often used after cytotoxic treatment, but long-term treatment is necessary, raising concerns regarding the accumulation of side effects. Still, some patients show a tendency to relapse even on this maintenance regimen and some even have a refractory course that creates a medical dilemma. For this situation, recent data have demonstrated an effect of monoclonal antibodies directed to B cells - rituximab, a drug that may also prove to be a therapeutic option in less complicated cases. Patients that do not respond to initial steroid treatment need genetic testing and a renal biopsy, since focal segmental glomerulosclerosis may be present. Treatment options include pulse methylprednisolone, often in addition to calcineurin inhibitors (mainly cyclosporine but also, recently, tacrolimus). Cyctotoxic treatment, especially intravenous cyclophosphamide, has been found to be effective in steroid-resistant nephrotic syndrome by some studies but is inferior to calcineurin inhibitors. In addition, mycophenolic acid and rituximab have been used in children with primary focal segmental glomerulosclerosis; however, response seems to be inferior in comparison with patients with steroid-sensitive nephrotic syndrome. Taken together, idiopathic nephrotic syndrome, including steroid-sensitive as well as steroid-resistant patients, is a potentially serious disorder. Although much progress has been made in recent years and a wide arsenal of immunological interventions is available, some patients have a treatment refractory course. Prospective studies or at least standardization of treatment for complicated cases is urgently needed. PMID:22111681

  3. BBN and the CMB constrain neutrino coupled light WIMPs

    NASA Astrophysics Data System (ADS)

    Nollett, Kenneth M.; Steigman, Gary

    2015-04-01

    In the presence of a light weakly interacting massive particle (WIMP) with mass m??30 MeV , there are degeneracies among the nature of the WIMP (fermion or boson), its couplings to the standard model particles (to electrons, positrons, and photons, or only to neutrinos), its mass m?, and the number of equivalent (additional) neutrinos, ? N?. These degeneracies cannot be broken by the cosmic microwave background (CMB) constraint on the effective number of neutrinos, Neff. However, since big bang nucleosynthesis (BBN) is also affected by the presence of a light WIMP and equivalent neutrinos, complementary BBN and CMB constraints can help to break some of these degeneracies. In a previous paper [K. M. Nollett and G. Steigman, Phys. Rev. D 89, 083508 (2014)] the combined BBN and Planck [P. A. R. Ade et al. (Planck Collaboration), Astron. Astrophys. 571, A16 (2014)] CMB constraints were used to explore the allowed ranges for m?, ? N?, and Neff in the case where the light WIMPs annihilate electromagnetically (EM) to photons and/or e± pairs. In this paper the BBN predictions for the primordial abundances of deuterium and 4He (along with 3He and 7Li) in the presence of a light WIMP that only couples (annihilates) to neutrinos [either standard model (SM) only or both SM and equivalent] are calculated. Recent observational estimates of the relic abundances of D and 4He are used to limit the light WIMP mass, the number of equivalent neutrinos, the effective number of neutrinos, and the present Universe baryon density (?Bh2 ). Allowing for a neutrino coupled light WIMP and ? N? equivalent neutrinos, the combined BBN and CMB data provide lower limits to the WIMP mass that depend very little on the nature of the WIMP (Majorana or Dirac fermion, real or complex scalar boson), with a best fit m??35 MeV , equivalent to no light WIMP at all. The analysis here excludes all neutrino coupled WIMPs with masses below a few MeV, with specific limits varying from 4 to 9 MeV depending on the nature of the WIMP. In the absence of a light WIMP (either EM or neutrino coupled), BBN alone prefers ? N? =0.50 ±0.23 , favoring neither the absence of equivalent neutrinos (? N?=0 ), nor the presence of a fully thermalized sterile neutrino (? N?=1 ). This result is consistent with the CMB constraint, Neff=3.30 ±0.27 [1], constraining "new physics" between BBN and recombination. Combining the BBN and CMB constraints gives ? N? =0.35 ±0.16 and Neff=3.40 ±0.16 . As a result, while BBN and the CMB combined require ? N? ?0 at ˜98 % confidence, they disfavor ? N? ?1 at >99 % confidence. Adding the possibility of a neutrino-coupled light WIMP extends the allowed range slightly downward for ? N? and slightly upward for Neff simultaneously, while leaving the best-fit values unchanged.

  4. Variation in Dehydration Tolerance, ABA Sensitivity and Related Gene Expression Patterns in D-Genome Progenitor and Synthetic Hexaploid Wheat Lines

    PubMed Central

    Kurahashi, Yumeto; Terashima, Akihiro; Takumi, Shigeo

    2009-01-01

    The wild wheat Aegilops tauschii Coss. has extensive natural variation available for breeding of common wheat. Drought stress tolerance is closely related to abscisic acid (ABA) sensitivity. In this study, 17 synthetic hexaploid wheat lines, produced by crossing the tetraploid wheat cultivar Langdon with 17 accessions of Ae. tauschii, were used for comparative analysis of natural variation in drought tolerance and ABA sensitivity. Ae. tauschii showed wide natural variation, with weak association between the traits. Drought-sensitive accessions of Ae. tauschii exhibited significantly less ABA sensitivity. D-genome variations observed at the diploid genome level were not necessarily reflected in synthetic wheats. However, synthetic wheats derived from the parental Ae. tauschii accessions with high drought tolerance were significantly more tolerant to drought stress than those from drought-sensitive accessions. Moreover, synthetic wheats with high drought tolerance showed significantly higher ABA sensitivity than drought-sensitive synthetic lines. In the hexaploid genetic background, therefore, weak association of ABA sensitivity with drought tolerance was observed. To study differences in gene expression patterns between stress-tolerant and -sensitive lines, levels of two Cor/Lea and three transcription factor gene transcripts were compared. The more tolerant accession of Ae. tauschii tended to accumulate more abundant transcripts of the examined genes than the sensitive accession under stress conditions. The expression patterns in the synthetic wheats seemed to be additive for parental lines exposed to drought and ABA treatments. However, the transcript levels of transcription factor genes in the synthetic wheats did not necessarily correspond to the postulated levels based on expression in parental lines. Allopolyploidization altered the expression levels of the stress-responsive genes in synthetic wheats. PMID:19582226

  5. Cultural differences in on-line sensitivity to emotional voices: comparing East and West

    PubMed Central

    Liu, Pan; Rigoulot, Simon; Pell, Marc D.

    2015-01-01

    Evidence that culture modulates on-line neural responses to the emotional meanings encoded by vocal and facial expressions was demonstrated recently in a study comparing English North Americans and Chinese (Liu et al., 2015). Here, we compared how individuals from these two cultures passively respond to emotional cues from faces and voices using an Oddball task. Participants viewed in-group emotional faces, with or without simultaneous vocal expressions, while performing a face-irrelevant visual task as the EEG was recorded. A significantly larger visual Mismatch Negativity (vMMN) was observed for Chinese vs. English participants when faces were accompanied by voices, suggesting that Chinese were influenced to a larger extent by task-irrelevant vocal cues. These data highlight further differences in how adults from East Asian vs. Western cultures process socio-emotional cues, arguing that distinct cultural practices in communication (e.g., display rules) shape neurocognitive activity associated with the early perception and integration of multi-sensory emotional cues. PMID:26074808

  6. The Sensitivity of Diffuse Large B-Cell Lymphoma Cell Lines to Histone Deacetylase Inhibitor-Induced Apoptosis Is Modulated by BCL-2 Family Protein Activity

    PubMed Central

    Thompson, Ryan C.; Vardinogiannis, Iosif; Gilmore, Thomas D.

    2013-01-01

    Background Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous disease and this variation can often be used to explain the response of individual patients to chemotherapy. One cancer therapeutic approach currently in clinical trials uses histone deacetylase inhibitors (HDACi’s) as monotherapy or in combination with other agents. Methodology/Principal Findings We have used a variety of cell-based and molecular/biochemical assays to show that two pan-HDAC inhibitors, trichostatin A and vorinostat, induce apoptosis in seven of eight human DLBCL cell lines. Consistent with previous reports implicating the BCL-2 family in regulating HDACi-induced apoptosis, ectopic over-expression of anti-apoptotic proteins BCL-2 and BCL-XL or pro-apoptotic protein BIM in these cell lines conferred further resistance or sensitivity, respectively, to HDACi treatment. Additionally, BCL-2 family antgonist ABT-737 increased the sensitivity of several DLBCL cell lines to vorinostat-induced apoptosis, including one cell line (SUDHL6) that is resistant to vorinostat alone. Moreover, two variants of the HDACi-sensitive SUDHL4 cell line that have decreased sensitivity to vorinostat showed up-regulation of BCL-2 family anti-apoptotic proteins such as BCL-XL and MCL-1, as well as decreased sensitivity to ABT-737. These results suggest that the regulation and overall balance of anti- to pro-apoptotic BCL-2 family protein expression is important in defining the sensitivity of DLBCL to HDACi-induced apoptosis. However, the sensitivity of DLBCL cell lines to HDACi treatment does not correlate with expression of any individual BCL-2 family member. Conclusions/Significance These studies indicate that the sensitivity of DLBCL to treatment with HDACi’s is dependent on the complex regulation of BCL-2 family members and that BCL-2 antagonists may enhance the response of a subset of DLBCL patients to HDACi treatment. PMID:23667527

  7. A sensitive sensor cell line for the detection of oxidative stress responses in cultured human keratinocytes.

    PubMed

    Hofmann, Ute; Priem, Melanie; Bartzsch, Christine; Winckler, Thomas; Feller, Karl-Heinz

    2014-01-01

    In the progress of allergic and irritant contact dermatitis, chemicals that cause the generation of reactive oxygen species trigger a heat shock response in keratinocytes. In this study, an optical sensor cell line based on cultured human keratinocytes (HaCaT cells) expressing green fluorescent protein (GFP) under the control of the stress-inducible HSP70B' promoter were constructed. Exposure of HaCaT sensor cells to 25 µM cadmium, a model substance for oxidative stress induction, provoked a 1.7-fold increase in total glutathione and a ~300-fold induction of transcript level of the gene coding for heat shock protein HSP70B'. An extract of Arnica montana flowers resulted in a strong induction of the HSP70B' gene and a pronounced decrease of total glutathione in keratinocytes. The HSP70B' promoter-based sensor cells conveniently detected cadmium-induced stress using GFP fluorescence as read-out with a limit of detection of 6 µM cadmium. In addition the sensor cells responded to exposure of cells to A. montana extract with induction of GFP fluorescence. Thus, the HaCaT sensor cells provide a means for the automated detection of the compromised redox status of keratinocytes as an early indicator of the development of human skin disorders and could be applied for the prediction of skin irritation in more complex in vitro 3D human skin models and in the development of micro-total analysis systems (µTAS) that may be utilized in dermatology, toxicology, pharmacology and drug screenings. PMID:24967604

  8. A Sensitive Sensor Cell Line for the Detection of Oxidative Stress Responses in Cultured Human Keratinocytes

    PubMed Central

    Hofmann, Ute; Priem, Melanie; Bartzsch, Christine; Winckler, Thomas; Feller, Karl-Heinz

    2014-01-01

    In the progress of allergic and irritant contact dermatitis, chemicals that cause the generation of reactive oxygen species trigger a heat shock response in keratinocytes. In this study, an optical sensor cell line based on cultured human keratinocytes (HaCaT cells) expressing green fluorescent protein (GFP) under the control of the stress-inducible HSP70B' promoter were constructed. Exposure of HaCaT sensor cells to 25 ?M cadmium, a model substance for oxidative stress induction, provoked a 1.7-fold increase in total glutathione and a ?300-fold induction of transcript level of the gene coding for heat shock protein HSP70B'. An extract of Arnica montana flowers resulted in a strong induction of the HSP70B' gene and a pronounced decrease of total glutathione in keratinocytes. The HSP70B' promoter-based sensor cells conveniently detected cadmium-induced stress using GFP fluorescence as read-out with a limit of detection of 6 ?M cadmium. In addition the sensor cells responded to exposure of cells to A. montana extract with induction of GFP fluorescence. Thus, the HaCaT sensor cells provide a means for the automated detection of the compromised redox status of keratinocytes as an early indicator of the development of human skin disorders and could be applied for the prediction of skin irritation in more complex in vitro 3D human skin models and in the development of micro-total analysis systems (?TAS) that may be utilized in dermatology, toxicology, pharmacology and drug screenings. PMID:24967604

  9. Differential sensitivity of telomerase from human hematopoietic stem cells and leukemic cell lines to mild hyperthermia.

    PubMed

    Deezagi, Abdolkhaleg

    2014-07-01

    We have investigated the effects of hyperthermia (HT) on cell proliferation and telomerase activity of human hematopoietic stem cells (HSCs) and compared with human leukemic cell lines (TF-1, K562 and HL-60). The cells were exposed to HT at 42 and 43 °C up to 120 min. The cells were incubated at 37 °C for 96 h. Then the cells were collected and assayed for cell proliferation, viability, telomerase activity, and terminal restriction fragment (TRF) lengths. The enzyme activity from HSCs was decreased up to 68.6 at 42 and 85.1 % at 43 °C for 120 min. This inhibition in leukemic cells was up to 28.9 and 53.6 % in TF-1; 53 and 63.9 % in K562; 45.2 and 61.1 % in HL-60 cells. The treated cells showed TRF lengths about 5.3 kb for control HL-60 cells, 5.0 kb for HL-60 cells treated at 42 and 4.5 kb at 43 °C for 120 min. In HSCs, the TRF length was about 4.5 kb for untreated cells and 4.0-4.5 kb for treated cells at 42 and 43 °C for 120 min. The time response curves indicated that, inhibition of the enzyme activity in leukemic cells was dependent to the time of exposure to HT. But in HSCs, the inhibition was reached to steady state at 15 min exposure to 43 °C heat stress. TRF length was constant at treated two types of cells, which implies that in cells subjected to mild HT no telomere shortening was observed. PMID:24590263

  10. Baryomorphosis: Relating the Baryon Asymmetry to the "WIMP Miracle"

    E-print Network

    John McDonald

    2011-04-06

    We present a generic framework, "baryomorphosis", which modifies the baryon asymmetry to be naturally of the order of a typical thermal relic WIMP density. We consider a simple scalar-based model to show how this is possible. This model introduces a sector in which a large initial baryon asymmetry is injected into particles ("annihilons") phi_B, \\bar{phi}_B of mass ~ 100 GeV - 1 TeV. phi_B-\\bar{phi}_B annihilations convert the initial phi_B, \\bar{phi}_B asymmetry to a final asymmetry with a thermal relic WIMP-like density. This subsequently decays to a conventional baryon asymmetry whose magnitude is naturally related to the density of thermal relic WIMP dark matter. In this way the two coincidences of baryons and dark matter i.e. why their densities are similar to each other and why they are both similar to a WIMP thermal relic density (the "WIMP miracle"), may be understood. The model may be tested by the production of annihilons at colliders.

  11. Resolving three-dimensional shape of sub-50?nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

    SciTech Connect

    Attota, Ravikiran Dixson, Ronald G.

    2014-07-28

    We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30?nm–40?nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22?nm (k?=?2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

  12. Resolving three-dimensional shape of sub-50 nm wide lines with nanometer-scale sensitivity using conventional optical microscopes

    NASA Astrophysics Data System (ADS)

    Attota, Ravikiran; Dixson, Ronald G.

    2014-07-01

    We experimentally demonstrate that the three-dimensional (3-D) shape variations of nanometer-scale objects can be resolved and measured with sub-nanometer scale sensitivity using conventional optical microscopes by analyzing 4-D optical data using the through-focus scanning optical microscopy (TSOM) method. These initial results show that TSOM-determined cross-sectional (3-D) shape differences of 30 nm-40 nm wide lines agree well with critical-dimension atomic force microscope measurements. The TSOM method showed a linewidth uncertainty of 1.22 nm (k = 2). Complex optical simulations are not needed for analysis using the TSOM method, making the process simple, economical, fast, and ideally suited for high volume nanomanufacturing process monitoring.

  13. Sensitive simultaneous determination of three sulfanilamide artificial sweeters by capillary electrophoresis with on-line preconcentration and contactless conductivity detection.

    PubMed

    Yang, Lirong; Zhou, ShengJi; Xiao, Yuezhou; Tang, Yufeng; Xie, Tianyao

    2015-12-01

    A sensitive method followed by capillary electrophoresis with on-line perconcentration and capacitively coupled contactless conductivity detection (CE-C(4)D) was evaluated as a novel approach for the determination of three sulfanilamide artificial sweeteners (acesulfame-K, sodium saccharin and sodium cyclamate) in beverages. The on-line preconcentration technique, namely field-amplified sample injection, coupled with CE-C(4)D were successfully developed and optimized. The separation was achieved within 10 min under the following conditions: an uncoated fused-silica capillary (45 cm × 50 ?m i.d., Leff=40 cm), 20 mmol L(-1) HAc as running buffer, separation voltage of -12 kV, electrokinetic injection of -11 kV × 8 s. The detection limits of acesulfame-K, sodium saccharin and sodium cyclamate were 4.4, 6.7 and 8.8 ?g L(-1), respectively. The relative standard deviation varied in the range of 3.0-5.0%. Results of this study show a great potential method for the fast screening of these artificial sweeteners contents in commercial beverages. PMID:26041216

  14. Recombination activating activity of XRCC1 analogous genes in X-ray sensitive and resistant CHO cell lines

    NASA Astrophysics Data System (ADS)

    Golubnitchaya-Labudová, O.; Portele, A.; Vaçata, V.; Lubec, G.; Rink, H.; Höfer, M.

    1997-10-01

    The XRCC1 gene (X-ray repair cross complementing) complements the DNA repair deficiency of the radiation sensitive Chinese hamster ovary (CHO) mutant cell line EM9 but the mechanism of the correction is not elucidated yet. XRCC1 shows substantial homology to the RAG2 gene (recombination activating gene) and we therefore tried to answer question, whether structural similarities (sequence of a putative recombination activating domain, aa 332-362 for XRCC1 and aa 286-316 in RAG2) would reflect similar functions of the homologous, putative recombination activating domain. PCR experiments revealed that no sequence homologous to the structural part of human XRCC1 was present in cDNA of CHO. Differential display demonstrated two putative recombination activating domains in the parental CHO line AA8 and one in the radiosensitive mutant EM9. Southern blot experiments showed the presence of several genes with partial homology to human XRCC1. Recombination studies consisted of expressing amplified target domains within chimeric proteins in recA - bacteria and subsequent detection of recombination events by sequencing the recombinant plasmids. Recombination experiments demonstrated recombination activating activity of all putative recombination activating domains amplified from AA8 and EM9 genomes as reflected by deletions within the insert of the recombinant plasmids. The recombination activating activity of XRCC1 analogues could explain a mechanism responsible for the correction of the DNA repair defect in EM9.

  15. DNA microarray reveals ZNF195 and SBF1 are potential biomarkers for gemcitabine sensitivity in head and neck squamous cell carcinoma cell lines

    PubMed Central

    Zhu, Min-Hui; Ji, Shun-Long; Zhang, Cai-Yun; Cui, Long; Xiong, Lei; Zheng, Hong-Liang

    2014-01-01

    Gemcitabine is a potential chemotherapy drug for treatment of head and neck squamous cell carcinoma (HNSCC), however, the poor or partial response of HNSCC patients to gemcitabine demonstrated the urgent need for gemcitabine biomarkers to improve the therapy. In present work, 10 HNSCC cell lines were employed to figure out the biomarkers for gemcitabine sensitivity. The sensitivities of these 10 cell lines to gemcitabine and the basal expression of these cell lines was investigated, the correlation between gemcitabine response (IC50 dose) and gene expression was investigated by Pearson correlation and FDR estimation. The top seven positive genes responsible for gemcitabine sensitivity were validated by qPCR in these 10 HNSCC cell lines, while only two genes (SBF1 and ZNF195) were expression-correlated to gemcitabine response. Furthermore, ZNF195 expression was closely associated with gemcitabine sensitivity in the subsequent independent validation in cell lines from various types of cancer. Our work might provide potential biomarkers for gemcitabine sensitivity in HNSCC and various type of cancer. PMID:24817947

  16. Lessons Learned from the Design and Implementation of Distributed Post-WIMP User

    E-print Network

    Reiterer, Harald

    Lessons Learned from the Design and Implementation of Distributed Post-WIMP User Interfaces Thomas spaces based on post-WIMP DUIs. (a) NiCE Discussion Room [5], (b) Desk- Piles [2] and (c) Facet desktop computing, its principles are also the foundation of novel post-WIMP (post-"Windows Icons Menu

  17. Search for Dark Matter WIMPs using Upward-Going Muons in

    E-print Network

    Tokyo, University of

    Search for Dark Matter WIMPs using Upward-Going Muons in Super{Kamiokande S. Desai, for the Super searches for Weakly Interacting Massive Particles (WIMPs) with the Super-Kamiokande detector using neutrino are calculated as a function of WIMP masses. 1 Introduction The \\dark-matter problem" is one of the most

  18. LIMITS ON THE WIMP-NUCLEON CROSS-SECTION FROM THE CRYOGENIC DARK MATTER SEARCH

    E-print Network

    California at Berkeley, University of

    LIMITS ON THE WIMP-NUCLEON CROSS-SECTION FROM THE CRYOGENIC DARK MATTER SEARCH R.W. SCHNEE 1 , R for WIMPs via their elastic-scattering interactions with nuclei while dis- criminating against interactions-independent WIMP-nucleon elastic-scattering cross-section that exclude unexplored parameter space above 10 GeV c 2

  19. Background-Particle Rates and Constraints on the WIMP-Nucleon

    E-print Network

    California at Berkeley, University of

    317 Chapter 8 Background-Particle Rates and Constraints on the WIMP-Nucleon Cross Section 8 and its implications for the WIMP-nucleon cross section. Rates for photons, electrons, and nuclear- recoil the single scatters to determine an exclusion limit on the spin- independent WIMP-nucleon elastic

  20. Uma Interface Hbrida para Desktop Integrando Realidade Virtual, Realidade Aumentada e 2D WIMP

    E-print Network

    Barbosa, Alberto

    Uma Interface Híbrida para Desktop Integrando Realidade Virtual, Realidade Aumentada e 2D WIMP interfaces in a common desktop setup. In addition, it is proposed the integration of a 2D WIMP (Windows with the mouse in the WIMP environment and in making data transferences, such as text, audio or video files

  1. Facilitating post-WIMP Interaction Programming using the Hierarchical State Machine Toolkit

    E-print Network

    Facilitating post-WIMP Interaction Programming using the Hierarchical State Machine Toolkit RenaudTk, instrumental interaction, post-WIMP interaction, software architecture 1 Introduction Programming interactive graphical user interfaces. However they result in a WIMP (Windows, Menus, Icons, Pointing) interaction style

  2. Search for Low-Mass WIMPs with SuperCDMS R. Agnese,18

    E-print Network

    California at Berkeley, University of

    Search for Low-Mass WIMPs with SuperCDMS R. Agnese,18 A.J. Anderson,4, M. Asai,8 D. Balakishiyeva particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg-days was analyzed for WIMPs with mass

  3. The ZEPLIN Dark Matter Search: Two Phase Xenon as a WIMP Target

    E-print Network

    The ZEPLIN Dark Matter Search: Two Phase Xenon as a WIMP Target Blair Nicholas Victor Edwards in the search of the expected rare interactions of Weakly Interacting Massive Particles, or WIMPs, with ordinary was operated underground at the Boulby Underground Laboratory, culminating in a WIMP search run lasting 57 days

  4. LIMITS ON THE WIMP-NUCLEON CROSS-SECTION FROM THE CRYOGENIC DARK MATTER SEARCH

    E-print Network

    California at Berkeley, University of

    LIMITS ON THE WIMP-NUCLEON CROSS-SECTION FROM THE CRYOGENIC DARK MATTER SEARCH R.J. GAITSKELL (FOR detectors to search for WIMPs via their elastic-scattering interactions with nuclei while discriminating site, give limits on the spin-independent WIMP- nucleon elastic-scattering cross-section that exclude

  5. WIMP search with the final year of CDMS II data

    SciTech Connect

    Hsu, L.; /Fermilab

    2010-07-01

    The Cryogenic Dark Matter Search (CDMS) has pioneered the use of ionization and athermal phonon signals to discriminate between candidate (nuclear recoil) and background (electron recoil) events in Ge crystals cooled to {approx}50 mK. The yield and timing information allows for the maximization of discovery potential by adjusting the expected background in the signal region to less than one event. A blind analysis on 612 kg-days of raw exposure from the CDMS II experiment was performed. Two events with an expected background of {approx}0.9 events were observed. No statistically significant evidence for WIMP interactions is reported. Combining this data with previously analyzed CDMS II data sets an upper limit on the WIMP-nucleon spin-independent cross-section of 3.8 x 10{sup -44} cm{sup 2} for a WIMP of mass 70 GeV/c{sup 2}.

  6. Constraints on Light WIMPs from SuperCDMS

    E-print Network

    A. J. Anderson; for the SuperCDMS Collaboration

    2014-05-16

    The SuperCDMS experiment searches for weakly interacting massive particles (WIMPs) using cryogenic germanium detectors that measure ionization and phonon energy. Several direct searches for WIMPs have recently reported excesses of events above their background expectations, which could be interpreted as WIMPs with masses in the 8-20 GeV/c^2 range. The excellent intrinsic signal-to-noise of SuperCDMS detectors and their powerful background rejection make SuperCDMS an ideal experiment to further test these signal hints. We present the results of two recent SuperCDMS analyses targeting this mass range: the first using Luke-Neganov amplification of the ionization signal to lower the effective energy threshold, and the second using multivariate methods to optimize background rejection in a larger 577 kg-d exposure.

  7. The Status of the Search for Low Mass WIMPs: 2013

    E-print Network

    David Cline

    2013-08-15

    Using information from a recent dark matter symposium at Marina del Rey and from various publications in 2012 and 2013, we discuss the most recent evidence and constraints on low mass WIMPs. There are now five separate experimental limits on such WIMPs, including a new paper on the XENON100 225 day exposure. There are very different experimental methods with different backgrounds that comprise this limit. We speculate on the possible sources of the reported low mass WIMP signals and background. We present recent arguments concerning DAMA that show the possible DM claims are likely misleading. We discuss the new CDMS claims for a signal and question the very low ionization in these events. We also discuss an analysis of XENON 100 data that uses information theory that further excludes the CDMS results.

  8. WIMP Dark Matter Inflation with Observable Gravity Waves

    E-print Network

    Nobuchika Okada; Qaisar Shafi

    2010-07-18

    We present a successful inflation model based on $\\lambda \\phi^4$ potential in which a Standard Model (SM) singlet inflaton $\\phi$, with mass of around a TeV or less, also plays the role of a weakly interacting scalar dark matter particle (WIMP). The WIMP relic abundance generated after inflation is in accord with the current observations. The spectral index $n_s$ lies within the WMAP 1-$\\sigma$ bounds, while the Planck satellite may observe the tensor-to-scalar ratio, a canonical measure of gravity waves, which we estimate lies between 0.003 and 0.007.An unbroken $Z_2$ parity ensures that the scalar WIMP is absolutely stable.

  9. A New Solar System Population of WIMP Dark Matter

    E-print Network

    Thibault Damour; Lawrence M. Krauss

    1998-12-29

    Perturbations due to the planets combined with the non-Coulomb nature of the gravitational potential in the Sun imply that WIMPs that are gravitationally captured by scattering in surface layers of the Sun can evolve into orbits that no longer intersect the Sun. For orbits with a semi-major axis $ 10^9$ years, leading to a previously unanticipated population intersecting Earth's orbit. For WIMPs detectable in the next generation of detectors, this population can provide a complementary signal, in the keV range, to that of galactic halo dark matter.

  10. The moment of truth for WIMP dark matter.

    PubMed

    Bertone, Gianfranco

    2010-11-18

    We know that dark matter constitutes 85 per cent of all the matter in the Universe, but we do not know of what it is made. Amongst the many dark matter candidates proposed, WIMPs (weakly interacting massive particles) occupy a special place, because they arise naturally from new theories that seek to extend the standard model of particle physics. With the advent of the Large Hadron Collider at CERN, and a new generation of astroparticle experiments, the moment of truth has come for WIMPs: either we will discover them in the next five to ten years, or we will witness their inevitable decline. PMID:21085174

  11. Search for WIMPS using Upward-Going Muons in MACRO

    E-print Network

    T. Montaruli for The MACRO Collaboration; M. Ambrosio et al

    1999-05-13

    We present updated results on the search for a neutrino signal from the core of the Earth and of the Sun induced by Weakly Interacting Massive Particles (WIMPs). In this paper we concentrate on neutralinos as WIMP candidates. The 971 and 642 events used respectively for the search from the Sun and from the Earth are compatible with the background of atmospheric neutrinos. Consequently we calculate flux limits for various search cones around these sources. Limits as a function of the neutralino mass are given and compared to the supersymmetric (SUSY) models.

  12. Characterising WIMPs at a future $e^+e^-$ Linear Collider

    E-print Network

    Christoph Bartels; Mikael Berggren; Jenny List

    2012-06-28

    We investigate the prospects for detecting and measuring the parameters of WIMP dark matter in a model independent way at the International Linear Collider. The signal under study is direct WIMP pair production with associated initial state radiation $e^+e^- \\rightarrow \\chi\\chi\\gamma$. The analysis accounts for the beam energy spectrum of the ILC and the dominant machine induced backgrounds. The influence of the detector parameters are incorporated by full simulation and event reconstruction within the framework of the ILD detector concept. We show that by using polarised beams, the detection potential is significantly increased by reduction of the dominant SM background of radiative neutrino production $e^+e^- \\rightarrow \

  13. BBN And The CMB Constrain Neutrino Coupled Light WIMPs

    E-print Network

    Kenneth M. Nollett; Gary Steigman

    2015-02-12

    (abridged) In the presence of a light WIMP (mass m_chi nature, its couplings to standard model particles, its mass, and the number of equivalent (additional) neutrinos, Delta N_nu. These degeneracies cannot be broken by the CMB constraint on the effective number of neutrinos, N_eff. However, since big bang nucleosynthesis (BBN) is also affected by a light WIMP and equivalent neutrinos, complementary BBN and CMB constraints can break some of the degeneracy. In a previous paper BBN and CMB were combined to explore allowed ranges for m_chi, Delta N_nu, and N_eff for light WIMPs that annihilate electromagnetically (EM) to photons and/or electrons/positrons. In this paper BBN predictions with a light WIMP that only couples to neutrinos are calculated. Recent observed abundances of ^2H and ^4He are used to limit m_chi, Delta N_nu, N_eff, and the present-day baryon density. Allowing for a neutrino coupled light WIMP and nonzero Delta N_nu, combined BBN and CMB data give lower limits to m_chi, with a best fit m_chi > 35 MeV, equivalent to no light WIMP at all. All masses below 4--9 MeV (depending on spin) are excluded. Without any light WIMP, BBN alone prefers Delta N_nu = 0.50 +- 0.23, favoring neither Delta N_nu = 0, nor a fully thermalized sterile neutrino (Delta N_nu = 1). This result is consistent with the CMB constraint, N_eff = 3.30 +- 0.27, limiting "new physics" between BBN and recombination. Combining BBN and CMB data gives Delta N_nu = 0.35 +- 0.16 and N_eff = 3.40 +- 0.16; while BBN and the CMB combined require Delta N_nu > 0 at ~98% confidence, they disfavor Delta N_nu > 1 at > 99% confidence. Allowing a neutrino-coupled light WIMP extends the allowed range slightly downward for Delta N_nu and slightly upward for N_eff simultaneously, leaving best-fit values unchanged.

  14. MicroRNA-302b Enhances the Sensitivity of Hepatocellular Carcinoma Cell Lines to 5-FU via Targeting Mcl-1 and DPYD

    PubMed Central

    Cai, Donghui; He, Kang; Chang, Su’e; Tong, Dongdong; Huang, Chen

    2015-01-01

    MiR-302b is a member of miR-302-367 cluster. The miR-302-367 cluster played important roles in maintaining pluripotency in human embryonic stem cells (hESCs) and has been proved to be capable of suppressing cell growth in several types of cancer cell lines including Hepatocellular Carcinoma (HCC) Cell lines. However, the role that miR-302b plays in the 5-Fluorouracil (5-FU) sensitivity of HCC has not been known. This study showed that miR-302b could enhance the sensitivity to 5-FU in HCC cell lines and verified its two putative targeted genes responsible for its 5-FU sensitivity. PMID:26457704

  15. Studies of variation in inherent sensitivities to radiation, 5-fluorouracil and methotrexate in a series of human and murine tumor cell lines in vitro

    SciTech Connect

    Bellamy, A.S.; Whelan, R.D.H.; Hill, B.T.

    1984-01-01

    Clinical studies have reported reduced response rates to subsequent chemotherapy in certain tumors recurring after radiotherapy. These authors have investigated whether there are any correlations between radiation and drug responses in vitro using a range of murine and human tumor cell lines. They have compared sensitivities to X-irradiation and to 24 hr exposures to two widely used antitumor drugs, methotrexate and 5-fluorouracil. The 4 murine lines selected showed a range of radiation responses with Do values of 0.48-0.76 Gy. Methotrexate sensitivities also exhibited an 800-fold difference which appeared to correlate inversely with radiation response. Sensitivity to 5-FU was less variable in these cells and was unrelated to radiation response. In contrast, in the human lines tested, no correlations were observed between drug sensitivities and radiation response. The six lines tested showed a range of radiation responses with Do values of 0.66-1.59 Gy. Methotrexate sensitivities ranged only over a 150-fold concentration but, contrasting with data from the murine cells, no correlation with radiation response was apparent. Similarly, no correlations between response to 5-fluorouracil and radiation or 5-fluorouracil and methotrexate were noted, which is inconsistent with results using murine cells.

  16. W. K. H. Panofsky Prize Talk: The Search for WIMP Dark Matter: CDMS Detectors

    NASA Astrophysics Data System (ADS)

    Cabrera, Blas

    2013-04-01

    As described in the accompanying talk by Bernard Sadoulet, the CDMS (cryogenic dark matter search) program has succeeded in pushing down by several orders of magnitude the sensitivity in the search for dark matter in the form of weakly interacting particles or WIMPs. In this talk we describe the technology that has enabled the CDMS detectors made of Ge and Si crystals to discriminate on an event by event basis electron recoils (most backgrounds from gammas) from nuclear recoils (the expected WIMP signal and neutrons). This rejection is accomplished by simultaneously measuring the ionization (electrons and holes in the semiconductor) and the phonons (lattice heat). To achieve the phonon measurement, the crystals are cooled to 0.05 K which allows the use of ultra low noise superconducting circuits. The phonon energy is collected at the surface of the crystals using Al films which absorb athermal phonons and produce quasiparticle excitations from the dissociated Cooper pairs. These excitations diffuse until the are trapped in superconducting tungsten transition edge sensors (TESs). The major advance of voltage biased TESs which are self biased in their transition region through negative feedback has been adopted very successfully for xray spectroscopy, gamma ray spectroscopy and CMB (cosmic microwave background) instruments. The most recent advance detectors called iZIPs (interleaved z-dependent ionization and phonon) provide a large improvement in surface electron rejection and remove that background for the next 200 kg Ge experiment and even for future ton scale experiments.

  17. DarkSide-50: A WIMP Search with a Two-phase Argon TPC

    NASA Astrophysics Data System (ADS)

    Meyers, P. D.; Agnes, P.; Alton, D.; Arisaka, K.; Back, H. O.; Baldin, B.; Biery, K.; Bonfini, G.; Bossa, M.; Brigatti, A.; Brodsky, J.; Budano, F.; Cadonati, L.; Calaprice, F.; Canci, N.; Candela, A.; Cao, H.; Cariello, M.; Cavalcante, P.; Chavarria, A.; Chepurnov, A.; Cocco, A. G.; Crippa, L.; DAngelo, D.; D'Incecco, M.; Davini, S.; De Deo, M.; Derbin, A.; Di Eusanio, F.; Di Pietro, G.; Edkins, E.; Empl, A.; Fan, A.; Fiorillo, G.; Fomenko, K.; Forster, G.; Franco, D.; Gabriele, F.; Galbiati, C.; Goretti, A.; Grandi, L.; Gromov, M.; Guan, M.; Guardincerri, Y.; Hackett, B.; Herner, K.; Humble, P.; Hungerford, E. V.; Ianni, Al.; Ianni, An.; Joliet, C.; Keeter, K.; Kendziora, C.; Kidner, S.; Kobychev, V.; Koh, G.; Korablev, D.; Korga, G.; Kurlej, A.; Li, P.; Loer, B.; Lombardi, P.; Love, C.; Ludhova, L.; Luitz, S.; Ma, Y.; Machulin, I.; Mandarano, A.; Mari, S.; Maricic, J.; Martoff, C. J.; Meregaglia, A.; Meroni, E.; Meyers, P. D.; Milincic, R.; Montanari, D.; Montuschi, M.; Monzani, M. E.; Mosteiro, P.; Mount, B.; Muratova, V.; Musico, P.; Nelson, A.; Okounkova, M.; Orsini, M.; Ortica, F.; Pagani, L.; Pallavicini, M.; Pantic, E.; Papp, L.; Parmeggiano, S.; Parsells, R.; Pelczar, K.; Pelliccia, N.; Perasso, S.; Perfetto, F.; Pocar, A.; Pordes, S.; Qian, H.; Randle, K.; Ranucci, G.; Razeto, A.; Reinhold, B.; Romani, A.; Rossi, B.; Rossi, N.; Rountree, S. D.; Sablone, D.; Saggese, P.; Saldanha, R.; Sands, W.; Segreto, E.; Semenov, D.; Shields, E.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Suvarov, Y.; Tartaglia, R.; Tatarowicz, J.; Testera, G.; Tonazzo, A.; Unzhakov, E.; Vogelaar, R. B.; Wada, M.; Wang, H.; Wang, Y.; Watson, A.; Westerdale, R.; Wojcik, M.; Wright, A.; Xu, J.; Yang, C.; Yoo, J.; Zavatarelli, S.; Zuzel, G.

    DarkSide-50 is a two phase argon TPC for direct dark matter detection which is installed at the Gran Sasso underground laboratory, Italy. DarkSide-50 has a 50-kg active volume and will make use of underground argon low in 39Ar. The TPC is installed inside an active neutron veto made with boron-loaded high radiopurity liquid scintillator. The neutron veto is installed inside a 1000 m3 water Cherenkov muon veto. The DarkSide-50 TPC and cryostat are assembled in two radon-free clean rooms to reduce radioactive contaminants. The overall design aims for a background free exposure after selection cuts are applied. The expected sensitivity for WIMP-nucleon cross section is of the order of 10-45 cm2 for WIMP masses around 100 GeV/c2. The commissioning and performance of the detector are described. Details of the low-radioactivity underground argon and other unique features of the projects are reported.

  18. CoGeNT-4: Prospects for an expanded search for light-mass WIMPS

    NASA Astrophysics Data System (ADS)

    Orrell, John; Aalseth, Craig; Collar, Juan; Day, Tony; Fields, Nicole; Fuller, Erin; Hossbach, Todd; Keillor, Marty; Kouzes, Dick; Overman, Cory; Vandevender, Brent

    2011-04-01

    The CoGeNT experiment located at the Soudan Underground Laboratory has reported an excess of events below an electron scattering equivalent of 1 keV. This result may be interpreted alternatively as either an unidentified background contribution or a signature of light-mass (5-10 GeV/c2) weakly interacting massive particle (WIMP) dark matter. The initial CoGeNT results were produced using a single 440 gram high-purity germanium radiation detector operated at liquid nitrogen temperature. To further test these unexpected results, an expanded CoGeNT-4 experimental design is under development. The shield design concept is presented and the science impact of a four-detector experiment is explored. Of particular interest is the sensitivity to a hypothesis for light-mass WIMP dark matter particles in the 5-10 GeV/c2 mass range that could potentially explain the initial CoGeNT results as well as the results of the DAMA/LIBRA experiment.

  19. Glutamine synthetase induction by glucocorticoids in the glucocorticoid-sensitive human leukemic cell line CEM-C7.

    PubMed

    Harmon, J M; Thompson, E B

    1982-02-01

    Treatment of CEM-C7 cells with glucocorticoids produces a 2.5-fold increase in the activity of the enzyme glutamine synthetase (GS). This increase is specific for steroids with glucocorticoid activity adn occurs over a range of steroid concentrations consistent with a receptor-mediated mechanism. Half-maximal and maximal inductions by dexamethasone (dex) occur at 2 X 10(-8) M and 2 X 10(-7) M dex, respectively, concentrations approximately equal to those necessary to produce half and full occupancy of glucocorticoid receptors. GS activity began to increase 1 hour after dex treatment and was complete by 12 hours. This is well before any of the growth inhibitory or cytolytic effects of dex on this cell line occur. This increase was dependent on the presence of glucocorticoid receptors and required both RNA and protein synthesis. Removal of dex following stimulation to maximal levels resulted in a decrease of GS activity to preinduced levels with a half-time of 5 hours. Glutamine deprivation of cells resulted in increased GS activity. However, even in the total absence of glutamine, dex treatment elicited a 2.0-2.5-fold increase in GS activity, ruling out inhibition of glutamine uptake as a mechanism for the dex-induced increase. Experiments with 5'-bromodeoxyuridine (BrdU) demonstrated that GS elevation was sensitive to BrdU substitution of DNA, while dex-induced growth inhibition was not. Therefore GS elevation and growth inhibition in this cell line appear to be independently expressed steroid responses. PMID:6121820

  20. A data acquisition system for two-dimensional position sensitive micropattern gas detectors with delay-line readout

    NASA Astrophysics Data System (ADS)

    Hanu, A. R.; Prestwich, W. V.; Byun, S. H.

    2015-04-01

    We present a data acquisition (DAQ) system for two-dimensional position sensitive micropattern gas detectors using the delay-line method for readout. The DAQ system consists of a field programmable gate array (FPGA) as the main data processor and our time-to-digital (TDC) mezzanine card for making time measurements. We developed the TDC mezzanine card around the Acam TDC-GPX ASIC and it features four independent stop channels referenced to a common start, a typical timing resolution of ~81 ps, and a 17-bit measurement range, and is compliant with the VITA 57.1 standard. For our DAQ system, we have chosen the Xilinx SP601 development kit which features a single Spartan 6 FPGA, 128 MB of DDR2 memory, and a serial USB interface for communication. Output images consist of 1024×1024 square pixels, where each pixel has a 32-bit depth and corresponds to a time difference of 162 ps relative to its neighbours. When configured for a 250 ns acquisition window, the DAQ can resolve periodic event rates up to 1.8×106 Hz without any loses and will report a maximum event rate of 6.11×105 Hz for events whose arrival times follow Poisson statistics. The integral and differential non-linearities have also been measured and are better than 0.1% and 1.5%, respectively. Unlike commercial units, our DAQ system implements the delay-line image reconstruction algorithm entirely in hardware and is particularly attractive for its modularity, low cost, ease of integration, excellent linearity, and high throughput rate.

  1. Dynamics of WIMPs in the solar system and implications for direct and indirect detection

    E-print Network

    Annika H. G. Peter; Scott Tremaine

    2008-10-14

    Semi-analytic treatments of the evolution of orbits of weakly interacting massive particles (WIMPs) in the solar system suggest that the WIMPs bound to the solar system may enhance the direct detection rate relative to that of the unbound population by up to a factor of order unity, and boost the flux of neutrinos from WIMP annihilation in the Earth by up to two orders of magnitude. To test these important but uncertain results, we perform a suite of numerical orbit integrations to explore the properties of the bound WIMP population as a function of the WIMP mass and the scattering cross section with baryonic matter. For regions of WIMP parameter space presently allowed by experiments, we find that (i) the bound WIMP population enhances the direct detection rate by at most ~1% relative to the rate from unbound halo WIMPs; (ii) it is unlikely that planned km^3-scale neutrino telescopes will detect neutrinos from WIMP annihilation in the Earth; (iii) the event rate from neutrinos produced by WIMP annihilation in the Sun may be much smaller than implied by the usual calculations, which assume that WIMPs scattered onto bound orbits are rapidly thermalized in the Sun.

  2. Gefitinib upregulates death receptor 5 expression to mediate rmhTRAIL-induced apoptosis in Gefitinib-sensitive NSCLC cell line

    PubMed Central

    Yan, Dong; Ge, Yang; Deng, Haiteng; Chen, Wenming; An, Guangyu

    2015-01-01

    Background Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) triggers apoptosis in tumor cells, but when used alone, it is not effective in the treatment of TRAIL-resistant tumors. Some studies have shown that gefitinib interacts with recombinant mutant human TRAIL (rmhTRAIL) to induce high levels of apoptosis in gefitinib-responsive bladder cancer cell lines; however, the molecular mechanisms underlying the anticancer effects are not fully understood. Several reports have shown that the death receptor 5 (DR5) plays an important role in sensitizing cancer cells to apoptosis induced by TRAIL. Therefore, we investigated the effects of the combination of drugs and the expression of the DR5 to analyze the growth of a gefitinib-responsive non-small cell lung cancer cell line PC9, which was treated with rmhTRAIL and gefitinib individually or in combination. Methods Human PC9 non-small cell lung cancer cells harboring an epidermal growth factor receptor mutation were used as a model for the identification of the therapeutic effects of gefitinib alone or in combination with rmhTRAIL, and cytotoxicity was assessed by MTT assays. Cell cycle and apoptosis were investigated using flow cytometry. Moreover, the effects of drugs on DR5, BAX, FLIP, and cleaved-caspase3 proteins expressions were analyzed using Western blot analyses. Finally, quantitative polymerase chain reaction analysis was carried out to assess whether rmhTRAIL and gefitinib modulate the expression of genes related to drug activity. Results Gefitinib and rmhTRAIL synergistically interact to inhibit cell proliferation, and apoptosis assessment demonstrated that associations of drug increased the apoptotic index. rmhTRAIL when used alone downregulated DR5 and upregulated BAX, FLIP, and cleaved-caspase3 proteins expressions. However, results obtained in Western blot analyses demonstrated that the combined treatment-induced cell apoptosis was achieved involving upregulated DR5, cleaved-caspase3, and BAX proteins expression and downregulated FLIP protein expression. Moreover, quantitative polymerase chain reaction showed that gefitinib modulated the expression of targets related to rmhTRAIL activity. Conclusion These results indicate that epidermal growth factor receptor inhibitors enhance rmhTRAIL antitumor activity in the gefitinib-responsive PC9 cell line, and upregulated DR5 expression plays a critical role in activating caspase-signaling apoptotic pathway. PMID:26170696

  3. Cytotoxicity of 5-fluorouracil-loaded pH-sensitive liposomal nanoparticles in colorectal cancer cell lines

    PubMed Central

    Udofot, Ofonime; Affram, Kevin; Israel, Bridg'ette; Agyare, Edward

    2015-01-01

    5-Fluorouracil (5-FU) is widely used in cancer therapy, either alone or in combination with other anti-cancer drugs. However, poor membrane permeability and a short half-life (5-20 min) due to rapid metabolism in the body necessitate the continuous administration of high doses of 5-FU to maintain the minimum therapeutic serum concentration. This is associated with significant side effects and a possibility of severe toxic effects. This study aimed to formulate 5-FU-loaded pH-sensitive liposomal nanoparticles (pHLNps-5-FU) and evaluate 5-FU release characteristics and anti-cancer effect of pHLNps-5-FU. Particle size and zeta potential were determined using a particle size analyzer. The release patterns of pHLNps-5-FU formulations were evaluated at 37°C at pH 3, 5, 6.5, and 7.4, while drug release kinetics of 5-FU from a pHLNp3–5-FU formulation were determined at pH 3 and 7.4 at different time points (37°C). Cell viability and clonogenic studies were conducted to evaluate the effectiveness of pHLNps-5-FU against HCT-116 and HT-29 cell lines while cellular uptake of rhodamine-labeled pHLNps-5-FU was determined by flow cytometry and confocal imaging. The average sizes of the pHLNp1–5-FU, pHLNp2–5-FU and pHLNp3–5-FU liposomes were 200nm ± 9.8nm, 181.9 nm ± 9.1 nm, and 164.3 nm ± 8.4 nm respectively. In vitro drug release of 5-FU from different pHLNps-5-FU formulations was the highest at pH 3.8. Both cell lines treated with pHLNps-5-FU exhibited reduced viability, two- or three-fold lower than that of 5-FU-treated cells. Flow cytometry and confocal imaging confirmed high uptake of rhodamine-labeled pHLNps-5-FU in both cell lines. The drug release profile of the chosen pHLNp3-5-FU formulation was optimal at pH 3 and had the poorest release profile at pH 7.4. The release profile of pHLNp3-5-FU showed that 5-FU release was two-fold higher at pH 3 than that at pH 7.4. This study demonstrates that pHLNp3-5-FU may be a potential candidate for the treatment of colorectal cancer.

  4. Analytic expressions for the kinetic decoupling of WIMPs

    E-print Network

    Visinelli, Luca

    2016-01-01

    We present a general expression for the values of the average kinetic energy and of the temperature of kinetic decoupling of a WIMP, valid for any cosmological model. We show an example of the usage of our solution when the Hubble rate has a power-law dependence on temperature.

  5. Status of CDMS Search for Dark Matter WIMPs

    E-print Network

    Neuhauser, Barbara

    the Stanford shallow site experiment (CDMS-I) which explore supersymmetric models where the lightest supersymmetric particle is often an excellent WIMP candidate. We will also report on the Soudan deep site fabrication. CP586, Relativistic Astrophysics: 20th Texas Symposium, edited by J. C. Wheeler and H. Mattel

  6. Improved constraints on WIMPs from the International Germanium Experiment IGEX

    E-print Network

    A. Morales; C. E. Aalseth; F. T. Avignone III; R. L. Brodzinski; S. Cebrian; E. Garcia; I. G. Irastorza; I. V. Kirpichnikov; A. A. Klimenko; H. S. Miley; J. Morales; A. Ortiz de Solorzano; S. B. Osetrov; V. S. Pogosov; J. Puimedon; J. H. Reeves; M. L. Sarsa; A. A. Smolnikov; A. G. Tamanyan; A. A. Vasenko; S. I. Vasiliev; J. A. Villar

    2002-01-16

    One IGEX 76Ge double-beta decay detector is currently operating in the Canfranc Underground Laboratory in a search for dark matter WIMPs, through the Ge nuclear recoil produced by the WIMP elastic scattering. A new exclusion plot, has been derived for WIMP-nucleon spin-independent interactions. To obtain this result, 40 days of data from the IGEX detector (energy threshold E \\~ 4 keV), recently collected, have been analyzed. These data improve the exclusion limits derived from all the other ionization germanium detectors in the mass region from 20 GeV to 200 GeV, where a WIMP supposedly responsible for the annual modulation effect reported by the DAMA experiment would be located. The new IGEX exclusion contour enters, by the first time, the DAMA region by using only raw data, with no background discrimination, and excludes its upper left part. It is also shown that with a moderate improvement of the detector performances, the DAMA region could be fully explored.

  7. Direct searches for Dark Matter Particles: WIMPs and axions

    E-print Network

    Igor G. Irastorza

    2005-09-18

    WIMPs and axions are the two best motivated candidates to compose the Dark Matter of the Universe. An important number of experimental groups are developing and using different techniques for their direct detection. An updated review of current searches is done, emphasizing latest results

  8. A light scalar wimp, the Higgs portal, and DAMA

    E-print Network

    Michel H. G. Tytgat

    2009-06-16

    In these proceedings, we report on the possible signatures of a light scalar WIMP, a dark matter candidate with M_DM ~ few GeV, which is supposed to interact with the Standard Model particles through the Higgs, and which might be related to the annual modulation observed by DAMA.

  9. Update on light WIMP limits: LUX, lite and light

    SciTech Connect

    Nobile, Eugenio Del; Gelmini, Graciela B.; Huh, Ji-Haeng; Gondolo, Paolo E-mail: gelmini@physics.ucla.edu E-mail: jhhuh@physics.ucla.edu

    2014-03-01

    We reexamine the current direct dark matter data including the recent CDMSlite and LUX data, assuming that the dark matter consists of light WIMPs, with mass close to 10 GeV/c{sup 2} with spin-independent and isospin-conserving or isospin-violating interactions. We compare the data with a standard model for the dark halo of our galaxy and also in a halo-independent manner. In our standard-halo analysis, we find that for isospin-conserving couplings, CDMSlite and LUX together exclude the DAMA, CoGeNT, CDMS-II-Si, and CRESST-II possible WIMP signal regions. For isospin-violating couplings instead, we find that a substantial portion of the CDMS-II-Si region is compatible with all exclusion limits. In our halo-independent analysis, we find that for isospin-conserving couplings, the situation is of strong tension between the positive and negative results, as it was before the LUX and CDMSlite bounds, which turn out to exclude the same possible WIMP signals as previous limits. For isospin-violating couplings, we find that LUX and CDMS-II-Si bounds together exclude or severely constrain the DAMA, CoGeNT and CRESST-II possible WIMP signals.

  10. Brain Arachidonic Acid Incorporation and Turnover are not Altered in the Flinders Sensitive Line Rat Model of Human Depression.

    PubMed

    Blanchard, Helene; Chang, Lisa; Rezvani, Amir H; Rapoport, Stanley I; Taha, Ameer Y

    2015-11-01

    Brain serotonergic signaling is coupled to arachidonic acid (AA)-releasing calcium-dependent phospholipase A2. Increased brain serotonin concentrations and disturbed serotonergic neurotransmission have been reported in the Flinders Sensitive Line (FSL) rat model of depression, suggesting that brain AA metabolism may be elevated. To test this hypothesis, (14)C-AA was intravenously infused to steady-state levels into control and FSL rats derived from the same Sprague-Dawley background strain, and labeled and unlabeled brain phospholipid and plasma fatty acid concentrations were measured to determine the rate of brain AA incorporation and turnover. Brain AA incorporation and turnover did not differ significantly between controls and FSL rats. Compared to controls, plasma unesterified docosahexaenoic acid was increased, and brain phosphatidylinositol AA and total lipid linoleic acid and n-3 and n-6 docosapentaenoic acid were significantly decreased in FSL rats. Several plasma esterified fatty acids differed significantly from controls. In summary, brain AA metabolism did not change in FSL rats despite reported increased levels of serotonin concentrations, suggesting possible post-synaptic dampening of serotonergic neurotransmission involving AA. PMID:26404538

  11. New beam line for time-of-flight medium energy ion scattering with large area position sensitive detector

    SciTech Connect

    Linnarsson, M. K.; Hallen, A.; Astroem, J.; Primetzhofer, D.; Legendre, S.; Possnert, G.

    2012-09-15

    A new beam line for medium energy ion mass scattering (MEIS) has been designed and set up at the Angstroem laboratory, Uppsala University, Sweden. This MEIS system is based on a time-of-flight (ToF) concept and the electronics for beam chopping relies on a 4 MHz function generator. Repetition rates can be varied between 1 MHz and 63 kHz and pulse widths below 1 ns are typically obtained by including beam bunching. A 6-axis goniometer is used at the target station. Scattering angle and energy of backscattered ions are extracted from a time-resolved and position-sensitive detector. Examples of the performance are given for three kinds of probing ions, {sup 1}H{sup +}, {sup 4}He{sup +}, and {sup 11}B{sup +}. Depth resolution is in the nanometer range and 1 and 2 nm thick Pt layers can easily be resolved. Mass resolution between nearby isotopes can be obtained as illustrated by Ga isotopes in GaAs. Taking advantage of the large size detector, a direct imaging (blocking pattern) of crystal channels are shown for hexagonal, 4H-SiC. The ToF-MEIS system described in this paper is intended for use in semiconductor and thin film areas. For example, depth profiling in the sub nanometer range for device development of contacts and dielectric interfaces. In addition to applied projects, fundamental studies of stopping cross sections in this medium energy range will also be conducted.

  12. New beam line for time-of-flight medium energy ion scattering with large area position sensitive detector

    NASA Astrophysics Data System (ADS)

    Linnarsson, M. K.; Hallén, A.; Åström, J.; Primetzhofer, D.; Legendre, S.; Possnert, G.

    2012-09-01

    A new beam line for medium energy ion mass scattering (MEIS) has been designed and set up at the Ångström laboratory, Uppsala University, Sweden. This MEIS system is based on a time-of-flight (ToF) concept and the electronics for beam chopping relies on a 4 MHz function generator. Repetition rates can be varied between 1 MHz and 63 kHz and pulse widths below 1 ns are typically obtained by including beam bunching. A 6-axis goniometer is used at the target station. Scattering angle and energy of backscattered ions are extracted from a time-resolved and position-sensitive detector. Examples of the performance are given for three kinds of probing ions, 1H+, 4He+, and 11B+. Depth resolution is in the nanometer range and 1 and 2 nm thick Pt layers can easily be resolved. Mass resolution between nearby isotopes can be obtained as illustrated by Ga isotopes in GaAs. Taking advantage of the large size detector, a direct imaging (blocking pattern) of crystal channels are shown for hexagonal, 4H-SiC. The ToF-MEIS system described in this paper is intended for use in semiconductor and thin film areas. For example, depth profiling in the sub nanometer range for device development of contacts and dielectric interfaces. In addition to applied projects, fundamental studies of stopping cross sections in this medium energy range will also be conducted.

  13. New beam line for time-of-flight medium energy ion scattering with large area position sensitive detector.

    PubMed

    Linnarsson, M K; Hallén, A; Åström, J; Primetzhofer, D; Legendre, S; Possnert, G

    2012-09-01

    A new beam line for medium energy ion mass scattering (MEIS) has been designed and set up at the A?ngstro?m laboratory, Uppsala University, Sweden. This MEIS system is based on a time-of-flight (ToF) concept and the electronics for beam chopping relies on a 4 MHz function generator. Repetition rates can be varied between 1 MHz and 63 kHz and pulse widths below 1 ns are typically obtained by including beam bunching. A 6-axis goniometer is used at the target station. Scattering angle and energy of backscattered ions are extracted from a time-resolved and position-sensitive detector. Examples of the performance are given for three kinds of probing ions, (1)H(+), (4)He(+), and (11)B(+). Depth resolution is in the nanometer range and 1 and 2 nm thick Pt layers can easily be resolved. Mass resolution between nearby isotopes can be obtained as illustrated by Ga isotopes in GaAs. Taking advantage of the large size detector, a direct imaging (blocking pattern) of crystal channels are shown for hexagonal, 4H-SiC. The ToF-MEIS system described in this paper is intended for use in semiconductor and thin film areas. For example, depth profiling in the sub nanometer range for device development of contacts and dielectric interfaces. In addition to applied projects, fundamental studies of stopping cross sections in this medium energy range will also be conducted. PMID:23020419

  14. Differential Mitochondrial Electron Transport through the Cyanide-Sensitive and Cyanide-Insensitive Pathways in Isonuclear Lines of Cytoplasmic Male Sterile, Male Fertile, and Restored Petunia1

    PubMed Central

    Connett, Marie B.; Hanson, Maureen R.

    1990-01-01

    Three pairs of isonuclear lines of cytoplasmic male sterile (CMS) and fertile Petunia cells (Petunia hybrida [Hook] Vilm. and Petunia parodii L.S.M.) grown in suspension culture were examined for sensitivity to inhibitors of respiratory electron transport at time-points after transfer into fresh media. Cells from CMS lines differed from cells of fertile lines in their utilization of the cyanide-insensitive oxidase pathway. Under our culture regime, after approximately 3 days of culture cells from the CMS lines exhibited much lower cyanide-insensitive, salicylhydroxamic acid-sensitive respiration than cells from the fertile lines. This respiratory difference was shown to be specific to the mitochondrial alternative oxidase pathway by using other characteristic inhibitors of mitochondrial electron transport in experiments with isolated mitochondria. Immature anthers from CMS plants also showed lower alternative oxidase activity relative to anthers from male fertile plants, but no such difference was detected in leaf tissue, ovary or perianth tissue, or anthers collected just prior to anthesis. A cell line from a fertile plant carrying a nuclear fertility restorer gene and the CMS cytoplasm exhibited increased activity of the alternative pathway compared with the CMS lines. PMID:16667667

  15. Increased fucosylation of glycolipids in a human leukaemia cell line (K562-Clone I) with decreased sensitivity to NK-mediated lysis.

    PubMed Central

    MacDougall, S L; Schwarting, G A; Parkinson, D; Sullivan, A K

    1987-01-01

    A subpopulation of human lymphoid cells called natural killers is able to lyse certain normal and neoplastic targets in an in vitro cytotoxicity assay. The molecules which enable them to recognize sensitive cells, or permit tumour cells to escape remain unknown. In the studies described here we have compared some of the plasma membrane characteristics of a NK-sensitive human leukaemia cell line (K562) with those of a partially resistant subclone derived from it (K562-Clone I). Gel electrophoresis of cell-surface proteins radiolabelled by lactoperoxidase-catalysed iodination, periodate-borohydride tritiation, or biosynthetically by incubation with [3H]fucose did not reveal any reproducible differences between the sensitive and resistant lines. However, analysis of glycolipids showed that Clone I incorporated significantly more fucose than did the parental line, and that it synthesized a minor population of complex structures not found in the original K562. A subclone of Clone I (Clone I-Con Ar1), made resistant to the toxic effects of concanavalin A, became sensitive once again to NK, and showed the parental glycolipid profile. These results suggest that the Clone I line, selected for resistance to NK, may have altered one or more of its intermediate oligosaccharides or pathways of fucose incorporation into glycolipid, and points to one process by which a tumor cell might modulate its surface to escape recognition by natural killers. Images Figure 1 Figure 2 Figure 3 PMID:3653928

  16. Loss in MCL-1 function sensitizes non-Hodgkin's lymphoma cell lines to the BCL-2-selective inhibitor venetoclax (ABT-199).

    PubMed

    Phillips, D C; Xiao, Y; Lam, L T; Litvinovich, E; Roberts-Rapp, L; Souers, A J; Leverson, J D

    2015-01-01

    As a population, non-Hodgkin's lymphoma (NHL) cell lines positive for the t(14;18) translocation and/or possessing elevated BCL2 copy number (CN; BCL2(High)) are exquisitely sensitive to navitoclax or the B-cell lymphoma protein-2 (BCL-2)-selective inhibitor venetoclax. Despite this, some BCL2(High) cell lines remain resistant to either agent. Here we show that the MCL-1-specific inhibitor A-1210477 sensitizes these cell lines to navitoclax. Chemical segregation of this synergy with the BCL-2-selective inhibitor venetoclax or BCL-XL-selective inhibitor A-1155463 indicated that MCL-1 and BCL-2 are the two key anti-apoptotic targets for sensitization. Similarly, the CDK inhibitor flavopiridol downregulated MCL-1 expression and synergized with venetoclax in BCL2(High) NHL cell lines to a similar extent as A-1210477. A-1210477 also synergized with navitoclax in the majority of BCL2(Low) NHL cell lines. However, chemical segregation with venetoclax or A-1155463 revealed that synergy was driven by BCL-XL inhibition in this population. Collectively these data emphasize that BCL2 status is predictive of venetoclax potency in NHL not only as a single agent, but also in the adjuvant setting with anti-tumorigenic agents that inhibit MCL-1 function. These studies also potentially identify a patient population (BCL2(Low)) that could benefit from BCL-XL (navitoclax)-driven combination therapy. PMID:26565405

  17. Loss in MCL-1 function sensitizes non-Hodgkin's lymphoma cell lines to the BCL-2-selective inhibitor venetoclax (ABT-199)

    PubMed Central

    Phillips, D C; Xiao, Y; Lam, L T; Litvinovich, E; Roberts-Rapp, L; Souers, A J; Leverson, J D

    2015-01-01

    As a population, non-Hodgkin's lymphoma (NHL) cell lines positive for the t(14;18) translocation and/or possessing elevated BCL2 copy number (CN; BCL2High) are exquisitely sensitive to navitoclax or the B-cell lymphoma protein-2 (BCL-2)-selective inhibitor venetoclax. Despite this, some BCL2High cell lines remain resistant to either agent. Here we show that the MCL-1-specific inhibitor A-1210477 sensitizes these cell lines to navitoclax. Chemical segregation of this synergy with the BCL-2-selective inhibitor venetoclax or BCL-XL-selective inhibitor A-1155463 indicated that MCL-1 and BCL-2 are the two key anti-apoptotic targets for sensitization. Similarly, the CDK inhibitor flavopiridol downregulated MCL-1 expression and synergized with venetoclax in BCL2High NHL cell lines to a similar extent as A-1210477. A-1210477 also synergized with navitoclax in the majority of BCL2Low NHL cell lines. However, chemical segregation with venetoclax or A-1155463 revealed that synergy was driven by BCL-XL inhibition in this population. Collectively these data emphasize that BCL2 status is predictive of venetoclax potency in NHL not only as a single agent, but also in the adjuvant setting with anti-tumorigenic agents that inhibit MCL-1 function. These studies also potentially identify a patient population (BCL2Low) that could benefit from BCL-XL (navitoclax)-driven combination therapy. PMID:26565405

  18. HSP90 inhibition downregulates thymidylate synthase and sensitizes colorectal cancer cell lines to the effect of 5FU-based chemotherapy

    PubMed Central

    Nagaraju, Ganji Purnachandra; Alese, Olatunji B.; Landry, Jerome; Diaz, Roberto; El-Rayes, Bassel F

    2014-01-01

    Cell cycle progression and DNA synthesis are essential steps in cancer cell growth. Thymidylate synthase (TS) is a therapeutic target for 5FU. We tested the hypothesis that HSP90 transcriptional and functional inhibition can inhibit cell cycle progression, downregulate TS levels and sensitize colorectal cancer (CRC) cell lines to the effects of 5FU. Treatment with ganetespib (50nM) for 24 hours inhibited cyclin D1 and pRb at the transcriptional and translational levels and induced p21, leading to G0/G1 cell cycle arrest in both CRC cell lines (HCT-116 and HT-29). This was associated with downregulation of E2F1 and its target gene TS. In addition, ganetespib inhibited PI3K/Akt and ERK signalling pathways. Similar effects were observed with HSP90 knockdown in both cell lines. Ganetespib sensitized CRC cell lines to the effects of oxaliplatin and 5FU. Similar effects were also observed in tumors from animals treated with ganetespib, oxaliplatin and 5FU. In this study, we present in vitro and animal data supporting that the targeting of HSP90 decreases CRC cell survival and proliferation. Ganetespib sensitizes CRC cell lines to the effects of 5FU-based chemotherapy. Combining HSP90 inhibitors with chemotherapy is a rational approach for future drug development in CRC. PMID:25296971

  19. Cytoskeletal Regulation Dominates Temperature-Sensitive Proteomic Changes of Hibernation in Forebrain of 13-Lined Ground Squirrels

    PubMed Central

    Hindle, Allyson G.; Martin, Sandra L.

    2013-01-01

    13-lined ground squirrels, Ictidomys tridecemlineatus, are obligate hibernators that transition annually between summer homeothermy and winter heterothermy – wherein they exploit episodic torpor bouts. Despite cerebral ischemia during torpor and rapid reperfusion during arousal, hibernator brains resist damage and the animals emerge neurologically intact each spring. We hypothesized that protein changes in the brain underlie winter neuroprotection. To identify candidate proteins, we applied a sensitive 2D gel electrophoresis method to quantify protein differences among forebrain extracts prepared from ground squirrels in two summer, four winter and fall transition states. Proteins that differed among groups were identified using LC-MS/MS. Only 84 protein spots varied significantly among the defined states of hibernation. Protein changes in the forebrain proteome fell largely into two reciprocal patterns with a strong body temperature dependence. The importance of body temperature was tested in animals from the fall; these fall animals use torpor sporadically with body temperatures mirroring ambient temperatures between 4 and 21°C as they navigate the transition between summer homeothermy and winter heterothermy. Unlike cold-torpid fall ground squirrels, warm-torpid individuals strongly resembled the homeotherms, indicating that the changes observed in torpid hibernators are defined by body temperature, not torpor per se. Metabolic enzymes were largely unchanged despite varied metabolic activity across annual and torpor-arousal cycles. Instead, the majority of the observed changes were cytoskeletal proteins and their regulators. While cytoskeletal structural proteins tended to differ seasonally, i.e., between summer homeothermy and winter heterothermy, their regulatory proteins were more strongly affected by body temperature. Changes in the abundance of various isoforms of the microtubule assembly and disassembly regulatory proteins dihydropyrimidinase-related protein and stathmin suggested mechanisms for rapid cytoskeletal reorganization on return to euthermy during torpor-arousal cycles. PMID:23951209

  20. Mitotic Slippage and Expression of Survivin Are Linked to Differential Sensitivity of Human Cancer Cell-Lines to the Kinesin-5 Inhibitor Monastrol

    PubMed Central

    Hershfinkel, Michal; Gheber, Larisa

    2015-01-01

    The mitotic Kinesin-5 motor proteins crosslink and slide apart antiparallel spindle microtubules, thus performing essential functions in mitotic spindle dynamics. Specific inhibition of their function by monastrol-like small molecules has been examined in clinical trials as anticancer treatment, with only partial success. Thus, strategies that improve the efficiency of monastrol-like anticancer drugs are required. In the current study, we examined the link between sensitivity to monastrol and occurrence of mitotic slippage in several human cell-lines. We found that the rank of sensitivity to monastrol, from most sensitive to least sensitive, is: AGS>HepG2>Lovo>Du145?HT29. We show correlation between the sensitivity of a particular cell-line to monastrol and the tendency of the same cell-line to undergo mitotic slippage. We also found that in the monastrol resistant HT29 cells, prolonged monastrol treatments increase mRNA and protein levels of the chromosomal passenger protein survivin. In contrast, survivin levels are not increased by this treatment in the monastrol-sensitive AGS cells. We further show that over-expression of survivin in the monastrol-sensitive AGS cells reduces mitotic slippage and increases resistance to monastrol. Finally, we show that during short exposure to monastrol, Si RNA silencing of survivin expression reduces cell viability in both AGS and HT29 cells. Our data suggest that the efficiency of anti-cancer treatment with specific kinesin-5 inhibitors may be improved by modulation of expression levels of survivin. PMID:26035434

  1. PICO-LON Project for WIMPs search

    E-print Network

    Ken-Ichi Fushimi; Kensuke Yasudai; Yuuki Kamedai; Hiroyasu Ejiri; Ryuta Hazama; Kayoko Ichihara; Kyoshiro Imagawa; Hiroshi Ito; Norihiko Koori; Hidehito Nakamura; Shintaro Nakayama; Masaharu Nomachi; Tatsushi Shima; Saori Umehara; Sei Yoshida

    2007-11-20

    Highly segmented inorganic crystal has been shown to have good performance for dark matter search. The energy resolution of ultra thin and large area NaI(Tl) scintillator has been developed. The estimated sensitivity for spin-dependent excitation of 127I was discussed. The recent status of low background measurement at Oto Cosmo Observatory is reported

  2. Ecdysteroids Sensitize MDR and Non-MDR Cancer Cell Lines to Doxorubicin, Paclitaxel, and Vincristine but Tend to Protect Them from Cisplatin

    PubMed Central

    Sipos, Péter; Dér, Katalin; Csábi, József; Miklos, Walter; Berger, Walter; Zalatnai, Attila; Amaral, Leonard; Molnár, Joseph; Szabó-Révész, Piroska

    2015-01-01

    Ecdysteroids, analogs of the insect molting hormone, are known for their various mild, nonhormonal bioactivities in mammals. Previously, we reported that less-polar ecdysteroids can modulate the doxorubicin resistance of a multidrug resistant (MDR) mouse lymphoma cell line expressing the human ABCB1 transporter. Here, we describe the ability of 20-hydroxyecdysone (1) and its mono- (2) and diacetonide (3) derivatives to sensitize various MDR and non-MDR cancer cell lines towards doxorubicin, paclitaxel, vincristine, or cisplatin. Drug IC50 values with or without ecdysteroid were determined by MTT assay. Compound 3 significantly sensitized all cell lines to each chemotherapeutic except for cisplatin, whose activity was decreased. In order to overcome solubility and stability issues for the future in vivo administration of compound 3, liposomal formulations were developed. By means of their combination index values obtained via checkerboard microplate method, a formulation showed superior activity to that of compound 3 alone. Because ecdysteroids act also on non-ABCB1 expressing (sensitive) cell lines, our results demonstrate that they do not or not exclusively exert their adjuvant anticancer activity as ABCB1 inhibitors, but other mechanisms must be involved, and they opened the way towards their in vivo bioactivity testing against various cancer xenografts. PMID:26075272

  3. Ecdysteroids sensitize MDR and non-MDR cancer cell lines to doxorubicin, paclitaxel, and vincristine but tend to protect them from cisplatin.

    PubMed

    Martins, Ana; Sipos, Péter; Dér, Katalin; Csábi, József; Miklos, Walter; Berger, Walter; Zalatnai, Attila; Amaral, Leonard; Molnár, Joseph; Szabó-Révész, Piroska; Hunyadi, Attila

    2015-01-01

    Ecdysteroids, analogs of the insect molting hormone, are known for their various mild, nonhormonal bioactivities in mammals. Previously, we reported that less-polar ecdysteroids can modulate the doxorubicin resistance of a multidrug resistant (MDR) mouse lymphoma cell line expressing the human ABCB1 transporter. Here, we describe the ability of 20-hydroxyecdysone (1) and its mono- (2) and diacetonide (3) derivatives to sensitize various MDR and non-MDR cancer cell lines towards doxorubicin, paclitaxel, vincristine, or cisplatin. Drug IC50 values with or without ecdysteroid were determined by MTT assay. Compound 3 significantly sensitized all cell lines to each chemotherapeutic except for cisplatin, whose activity was decreased. In order to overcome solubility and stability issues for the future in vivo administration of compound 3, liposomal formulations were developed. By means of their combination index values obtained via checkerboard microplate method, a formulation showed superior activity to that of compound 3 alone. Because ecdysteroids act also on non-ABCB1 expressing (sensitive) cell lines, our results demonstrate that they do not or not exclusively exert their adjuvant anticancer activity as ABCB1 inhibitors, but other mechanisms must be involved, and they opened the way towards their in vivo bioactivity testing against various cancer xenografts. PMID:26075272

  4. Higher Levels of c-Met Expression and Phosphorylation Identify Cell Lines With Increased Sensitivity to AMG-458, a Novel Selective c-Met Inhibitor With Radiosensitizing Effects

    SciTech Connect

    Li Bo; Torossian, Artour; Sun, Yunguang; Du, Ruihong; Dicker, Adam P.; Lu Bo

    2012-11-15

    Purpose: c-Met is overexpressed in some non-small cell lung cancer (NSCLC) cell lines and tissues. Cell lines with higher levels of c-Met expression and phosphorylation depend on this receptor for survival. We studied the effects of AMG-458 on 2 NSCLC cell lines. Methods and Materials: 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl) -2H-tetrazolium assays assessed the sensitivities of the cells to AMG-458. Clonogenic survival assays illustrated the radiosensitizing effects of AMG-458. Western blot for cleaved caspase 3 measured apoptosis. Immunoblotting for c-Met, phospho-Met (p-Met), Akt/p-Akt, and Erk/p-Erk was performed to observe downstream signaling. Results: AMG-458 enhanced radiosensitivity in H441 but not in A549. H441 showed constitutive phosphorylation of c-Met. A549 expressed low levels of c-Met, which were phosphorylated only in the presence of exogenous hepatocyte growth factor. The combination of radiation therapy and AMG-458 treatment was found to synergistically increase apoptosis in the H441 cell line but not in A549. Radiation therapy, AMG-458, and combination treatment were found to reduce p-Akt and p-Erk levels in H441 but not in A549. H441 became less sensitive to AMG-458 after small interfering RNA knockdown of c-Met; there was no change in A549. After overexpression of c-Met, A549 became more sensitive, while H441 became less sensitive to AMG-458. Conclusions: AMG-458 was more effective in cells that expressed higher levels of c-Met/p-Met, suggesting that higher levels of c-Met and p-Met in NSCLC tissue may classify a subset of tumors that are more sensitive to molecular therapies against this receptor.

  5. Direct and indirect limits on the electro-magnetic form factors of WIMPs

    E-print Network

    Maxim Pospelov; Tonnis ter Veldhuis

    2000-03-22

    We use the results of direct and indirect searches for weakly interacting massive particles (WIMPs) to obtain bounds on various electro-magnetic form factors of WIMPs. The limits on the recoil signal in underground dark matter detection experiments, with standard assumptions about the density and r.m.s. velocity of WIMPs in the halo, can be translated into the following model-independent bounds on the magnetic dipole, electric dipole, quadrupole and anapole moments and the polarizability of WIMPs: mu/mu_n WIMP mass of 100 GeV. The limits on fluxes of highly energetic neutrinos produced in the annihilation of WIMPs in the center of the earth and the sun lead to somewhat stronger, but more model dependent bounds.

  6. Cosmological Radio Emission induced by WIMP Dark Matter

    E-print Network

    N. Fornengo; R. Lineros; M. Regis; M. Taoso

    2012-03-05

    We present a detailed analysis of the radio synchrotron emission induced by WIMP dark matter annihilations and decays in extragalactic halos. We compute intensity, angular correlation, and source counts and discuss the impact on the expected signals of dark matter clustering, as well as of other astrophysical uncertainties as magnetic fields and spatial diffusion. Bounds on dark matter microscopic properties are then derived, and, depending on the specific set of assumptions, they are competitive with constraints from other indirect dark matter searches. At GHz frequencies, dark matter sources can become a significant fraction of the total number of sources with brightness below the microJansky level. We show that, at this level of fluxes (which are within the reach of the next-generation radio surveys), properties of the faint edge of differential source counts, as well as angular correlation data, can become an important probe for WIMPs.

  7. WIMP dark matter direct-detection searches in noble gases

    NASA Astrophysics Data System (ADS)

    Baudis, Laura

    2014-09-01

    Cosmological observations and the dynamics of the Milky Way provide ample evidence for an invisible and dominant mass component. This so-called dark matter could be made of new, colour and charge neutral particles, which were non-relativistic when they decoupled from ordinary matter in the early universe. Such weakly interacting massive particles (WIMPs) are predicted to have a non-zero coupling to baryons and could be detected via their collisions with atomic nuclei in ultra-low background, deep underground detectors. Among these, detectors based on liquefied noble gases have demonstrated tremendous discovery potential over the last decade. After briefly introducing the phenomenology of direct dark matter detection, I will review the main properties of liquefied argon and xenon as WIMP targets and discuss sources of background. I will then describe existing and planned argon and xenon detectors that employ the so-called single- and dual-phase detection techniques, addressing their complementarity and science reach.

  8. An intermediate framework between WIMP, FIMP, and EWIP dark matter

    SciTech Connect

    Yaguna, Carlos E.

    2012-02-01

    WIMP (Weakly Interacting Massive Particle), FIMP (Feebly interacting Massive Particle) and EWIP (Extremely Weakly Interacting Particle) dark matter are different theoretical frameworks that have been postulated to explain the dark matter. In this paper we examine an intermediate scenario that combines features from these three frameworks. It consists of a weakly interacting particle — à la WIMP — that does not reach thermal equilibrium in the early Universe — à la FIMP — and whose relic density is determined by the reheating temperature of the Universe — à la EWIP. As an example, an explicit realization of this framework, based on the singlet scalar model of dark matter, is analyzed in detail. In particular, the relic density is studied as a function of the parameters of the model, and the new viable region within this intermediate scenario is determined. Finally, it is shown that this alternative framework of dark matter allows for arbitrarily heavy dark matter particles and that it suggests a connection between dark matter and inflation.

  9. R-parity preserving super-WIMP decays

    E-print Network

    Maxim Pospelov; Michael Trott

    2009-04-14

    We point out that when the decay of one electroweak scale super-WIMP state to another occurs at second order in a super-weak coupling constant, this can naturally lead to decay lifetimes that are much larger than the age of the Universe, and create observable consequences for the indirect detection of dark matter. We demonstrate this in a supersymmetric model with Dirac neutrinos, where the right-handed scalar neutrinos are the lightest and next-to-lightest supersymmetric partners. We show that this model produces a super-WIMP decay rate scaling as m_nu^4/(weak scale)^3, and may significantly enhance the fraction of energetic electrons and positrons over anti-protons in the decay products. Such a signature is consistent with the observations recently reported by the PAMELA experiment.

  10. Cosmological radio emission induced by WIMP Dark Matter

    SciTech Connect

    Fornengo, N.; Regis, M.; Lineros, R.; Taoso, M. E-mail: rlineros@ific.uv.es E-mail: mtaoso@phas.ubc.ca

    2012-03-01

    We present a detailed analysis of the radio synchrotron emission induced by WIMP dark matter annihilations and decays in extragalactic halos. We compute intensity, angular correlation, and source counts and discuss the impact on the expected signals of dark matter clustering, as well as of other astrophysical uncertainties as magnetic fields and spatial diffusion. Bounds on dark matter microscopic properties are then derived, and, depending on the specific set of assumptions, they are competitive with constraints from other indirect dark matter searches. At GHz frequencies, dark matter sources can become a significant fraction of the total number of sources with brightness below the microJansky level. We show that, at this level of fluxes (which are within the reach of the next-generation radio surveys), properties of the faint edge of differential source counts, as well as angular correlation data, can become an important probe for WIMPs.

  11. A light scalar WIMP through the Higgs portal?

    E-print Network

    Michel H. G. Tytgat

    2010-12-02

    In these proceedings, I report on the status of a simple singlet scalar dark matter model in the light of recent results from both direct detection experiments, in particular DAMA, CoGeNT, CDMS-II and Xenon10/100, and indirect searches, in particular Fermi-LAT. Specifically, I confront the light scalar WIMP candidates, M_DM ~ few GeV, that are consistent with CoGeNT and/or DAMA, to constraints that may be set using the recent Fermi-LAT data on Milky Way dwarf spheroidal galaxies (dSphs) and the isotropic diffuse gamma-ray emission. I show that the latter observations set relevant exclusion limits on the lightest WIMP candidates.

  12. Gene expression changes induced by skin sensitizers in the KeratinoSens™ cell line: Discriminating Nrf2-dependent and Nrf2-independent events.

    PubMed

    Emter, Roger; van der Veen, Jochem W; Adamson, Greg; Ezendam, Janine; van Loveren, Henk; Natsch, Andreas

    2013-12-01

    The KeratinoSens™ assay is an in vitro screen for the skin sensitization potential of chemicals. It is based on a luciferase reporter gene under the control of the antioxidant response element of the aldoketoreductase gene AKR1C2. The transferability, reproducibility, and predictivity of the KeratinoSens™ assay have been investigated in detail and it is currently under assessment at the European Center for Validation of Alternatives to animal testing (ECVAM). Here we investigate the sensitizer-induced gene expression in the KeratinoSens™ cell line at the mRNA level and discriminate Nrf2-dependent and Nrf2-independent events by using siRNA to better characterize this test system at the molecular level. The results show that (i) the sensitizer-induced luciferase signal in KeratinoSens™ cells is completely dependent on Nrf2. The same holds true for the luciferase induction observed for the false positive chemical Tween80, indicating that the false positive result is not due to recruitment of an alternative transcription factor. (ii) Luciferase induction parallels the induction of endogenous Nrf2-dependent genes, indicating that the luciferase signal is representative for the sensitizer-induced Nrf2-response. (iii) The induction by sensitizers of additional genetic markers related to heat shock proteins and cellular stress could be reproduced in the KeratinoSens™ cell line and they were shown to be Nrf2-independent. These results confirm that the KeratinoSens™ cell line is a rapid and adequate screening tool to assess the sensitizer-induced Nrf2-response in keratinocytes. PMID:24055896

  13. Equivalent neutrinos, light WIMPs, and the chimera of dark radiation

    NASA Astrophysics Data System (ADS)

    Steigman, Gary

    2013-05-01

    According to conventional wisdom, in the standard model (SM) of particle physics and cosmology the “effective number of neutrinos” measured in the late Universe is Neff=3 (more precisely, 3.046). For extensions of the standard model allowing for the presence of ?N? “equivalent neutrinos” (or “dark radiation”), it is generally the case that Neff>3. These canonical results are reconsidered, demonstrating that a measurement of Neff>3 can be consistent with ?N?=0 (“dark radiation without dark radiation”). Conversely, a measurement consistent with Neff=3 is not inconsistent with the presence of dark radiation (?N?>0). In particular, if there is a light weakly interacting massive particle (WIMP) that annihilates to photons after the SM neutrinos have decoupled, the photons are heated beyond their usual heating from e± annihilation, reducing the late time ratio of neutrino and photon temperatures (and number densities), leading to Neff<3. This opens the window for one or more equivalent neutrinos, including “sterile neutrinos,” to be consistent with Neff=3. By reducing the neutrino number density in the present Universe, this also allows for more massive neutrinos, relaxing the current constraints on the sum of the neutrino masses. In contrast, if the light WIMP couples only to the SM neutrinos and not to the photons and e± pairs, its late time annihilation heats the neutrinos but not the photons, resulting in Neff>3 even in the absence of equivalent neutrinos or dark radiation. A measurement of Neff>3 is no guarantee of the presence of equivalent neutrinos or dark radiation. In the presence of a light WIMP and/or equivalent neutrinos, there are degeneracies among the light WIMP mass and its nature (fermion or boson, as well as its couplings to neutrinos and photons), the number and nature (fermion or boson) of the equivalent neutrinos, and their decoupling temperature (the strength of their interactions with the SM particles). As the analysis here reveals, there’s more to a measurement of Neff than meets the eye.

  14. Inhibition of PI3K/Akt/mTOR signaling pathway enhances the sensitivity of the SKOV3/DDP ovarian cancer cell line to cisplatin in vitro

    PubMed Central

    Cai, Yunlang; Tan, Xiaoqiang; Liu, Jun; Shen, Yang; Wu, Di; Ren, Mulan; Yu, Dandan

    2014-01-01

    The activation of the PI3K/AKT/mTOR pathway plays a key role in ovarian cancer tumorigenesis, progression and chemotherapy resistance. This study aimed to explore the possible mechanism that PI-103, a dual inhibitor of phosphatidylinositide 3-kinase and mTOR, enhances the sensitivity of SKOV3/DDP ovarian cancer cell line to cisplatin chemotherapy. The results showed that PI-103 could significantly increase the sensitivity of SKVO3/DDP cells to cisplatin through inhibiting the activation of PI3K/Akt/mTOR signaling pathway and inducing cell cycle arrest and apoptosis. PMID:25400422

  15. Dark Matter; Modification of f(R) or Wimps Miracle

    E-print Network

    A. Övgün

    2013-01-23

    The identity of dark matter is one of the key outstanding problems in both particle and astrophysics. In this thesis, I review some candidates of dark matter, especially WIMPs (weakly interacting massive particles) which is one of the best candidate so it is called that WIMPs miracle. In addition of this, there are also some theories of modification of gravity, by changing the law of gravity, it could be possible that the dark matter observations are explained. Until the dark matter particle is detected, there is some room for uncertainty. So we should consider every part of the problem and solve it. Dark matter problem is covering a large area so every possibility is important. So f(R) gravity is also reviewed in this thesis and some theories are considered as a possible solution of dark matter problem. Finally we highlight that, even in the case of WIMPs or another particles solution, f(R) gravity is also can be used for this problem. However, last words will be said by experiments.

  16. Dark Matter; Modification of f(R) or Wimps Miracle

    E-print Network

    Övgün, A

    2013-01-01

    The identity of dark matter is one of the key outstanding problems in both particle and astrophysics. In this thesis, I review some candidates of dark matter, especially WIMPs (weakly interacting massive particles) which is one of the best candidate so it is called that WIMPs miracle. In addition of this, there are also some theories of modification of gravity, by changing the law of gravity, it could be possible that the dark matter observations are explained. Until the dark matter particle is detected, there is some room for uncertainty. So we should consider every part of the problem and solve it. Dark matter problem is covering a large area so every possibility is important. So f(R) gravity is also reviewed in this thesis and some theories are considered as a possible solution of dark matter problem. Finally we highlight that, even in the case of WIMPs or another particles solution, f(R) gravity is also can be used for this problem. However, last words will be said by experiments.

  17. No WIMP mini-spikes in dwarf spheroidal galaxies

    NASA Astrophysics Data System (ADS)

    Wanders, Mark; Bertone, Gianfranco; Volonteri, Marta; Weniger, Christoph

    2015-04-01

    The formation of black holes inevitably affects the distribution of dark and baryonic matter in their vicinity, leading to an enhancement of the dark matter density, called spike, and if dark matter is made of WIMPs, to a strong enhancement of the dark matter annihilation rate. Spikes at the center of galaxies like the Milky Way are efficiently disrupted by baryonic processes, but mini-spikes can form and survive undisturbed at the center of dwarf spheroidal galaxies. We show that Fermi LAT satellite data allow to set very stringent limits on the existence of mini-spikes in dwarf galaxies: for thermal WIMPs with mass between 100 GeV and 1 TeV, we obtain a maximum black hole mass between 100 and 1000 Msolar, ruling out black holes masses extrapolated from the M-? relationship in a large region of the parameter space. We also performed Monte Carlo simulations of merger histories of black holes in dwarf spheroidals in a scenario where black holes form from the direct collapse of primordial gas in early halos, and found that this specific formation scenario is incompatible at the 84% CL with dark matter being in the form of thermal WIMPs.

  18. Can WIMP Dark Matter overcome the Nightmare Scenario?

    E-print Network

    Shinya Kanemura; Shigeki Matsumoto; Takehiro Nabeshima; Nobuchika Okada

    2010-05-31

    Even if new physics beyond the Standard Model (SM) indeed exists, the energy scale of new physics might be beyond the reach at the Large Hadron Collider (LHC) and the LHC could find only the Higgs boson but nothing else. This is the so-called "nightmare scenario". On the other hand, the existence of the dark matter has been established from various observations. One of the promising candidates for thermal relic dark matter is a stable and electric charge-neutral Weakly Interacting Massive Particle (WIMP) with the mass below the TeV scale. In the nightmare scenario, we introduce a WIMP dark matter singlet under the SM gauge group, which only couples to the Higgs doublet at the lowest order, and investigate a possibility that such WIMP dark matter can be a clue to overcome the nightmare scenario via various phenomenological tests such as the dark matter relic abundance, the direct detection experiments for the dark matter particle, and the production of the dark matter particle at the LHC.

  19. Resonant scattering and recombination of pseudo-degenerate WIMPs

    E-print Network

    Maxim Pospelov; Adam Ritz

    2008-08-27

    We consider the direct and indirect detection signatures of WIMPs \\chi^0 in kinematic regimes with a heavier, but nearly degenerate, charged state \\chi^{+-}. For small splittings of O(10) MeV, the scattering of WIMPs off nuclei may be dominated by inelastic recombination processes mediated by the formation of (\\chi^- N) bound states, leading to a distinct signature for direct detection. These cross-sections are bound primarily by limits on the abundance of heavy isotopes, and may be considerably larger than the elastic scattering cross section in more conventional models. If the mass splitting is too large for recombination to occur, there may still be a significant resonant enhancement of loop-induced electromagnetic form-factors of the WIMP, which can enhance the elastic scattering cross-section. We also discuss how this regime affects the annihilation cross-section and indirect detection signatures, and note the possibility of a significant mono-energetic \\gamma-signal, mediated by resonant processes near the (\\chi^+\\chi^-) bound state threshold.

  20. Theoretical direct WIMP detection rates for transitions to excited states

    E-print Network

    J. D. Vergados; H. Ejiri; K. G. Savvidy

    2013-07-17

    The recent WMAP and Planck data have confirmed that exotic dark matter together with the vacuum energy (cosmological constant) dominate in the flat Universe. Many extensions of the standard model provide dark matter candidates, in particular Weakly Interacting Massive Particles (WIMPs). %Supersymmetry provides a natural dark matter candidate, the lightest supersymmetric particle (LSP). Thus the direct dark matter detection is central to particle physics and cosmology. Most of the research on this issue has hitherto focused on the detection of the recoiling nucleus. In this paper we study transitions to the excited states, possible in some nuclei, which have sufficiently low lying excited states. Good examples are the first excited states of I-127 and Xe-129. %focusing on the first excited state at 50 keV of Iodine A=127. We find appreciable branching ratios for the inelastic scattering mediated by the spin cross sections. %find that the transition rate to this excited state is about 5 %percent of the transition to the ground state for low mass WIMPS, but the branching ratio can be much larger in the case pf heaver WIMPS. So, in principle, the extra signature of the gamma ray following the de-excitation of these states can, in principle, be exploited experimentally.

  1. Light WIMPs, Equivalent Neutrinos, BBN, and the CMB

    E-print Network

    Steigman, Gary

    2014-01-01

    Recent updates to the observational determinations of the primordial abundances of helium and deuterium are compared to the predictions of BBN to infer the universal ratio of baryons to photons (or, the present Universe baryon mass density parameter Omega_B h^2), as well as to constrain the effective number of neutrinos (N_eff) and the number of equivalent neutrinos (Delta N_nu). These BBN results are compared to those derived independently from the Planck CMB data. In the absence of a light WIMP (chi), N_eff = 3.05(1 + Delta N_nu/3). In this case, there is excellent agreement between BBN and the CMB, but the joint fit finds that Delta N_nu = 0.40 +/- 0.17, disfavoring standard big bang nucleosynthesis (SBBN: Delta N_nu = 0) at 2.4 sigma, as well as a sterile neutrino (Delta N_nu = 1) at 3.5 sigma. In the presence of a light WIMP, the relation between N_eff and Delta N_nu depends on the WIMP mass, leading to degeneracies among N_eff, Delta N_nu, and m_chi. The complementary and independent BBN and CMB data ca...

  2. Search for pseudoscalar-mediated WIMPs in t ?c transitions with missing energy

    NASA Astrophysics Data System (ADS)

    Jia, Lian-Bao

    2015-10-01

    The recent astronomical observation of GeV gamma-ray excess from the Galactic center was suggested due to a b b ¯ mode in the tens GeV of weakly interacting massive particle (WIMP) pair annihilations, and this mode was also explored by the new dwarf galaxy observation. Considering the case where the WIMP pair mass is below the top quark mass, a pseudoscalar ? is studied in this article, which mediates the interactions between the standard model fermions and fermionic WIMPs and the neutral flavor-changing interactions in standard model fermion sectors. The b b ¯ mode is favored in WIMP pair annihilations, while the WIMP-nucleus scattering is highly suppressed in direct detection. Alternative schemes of t ?c decay and single top production are employed to search the WIMPs. Assuming the mass of the WIMPs is around 5-60 GeV and with reasonable inputs by the constraints, the branching ratio Bt ?c ? ¯ ? of a top quark decaying into a charm quark and a WIMP pair is derived of order 1 0-8- 1 0-5 ; thus, careful studies in the future on top physics may help to gain a better understanding of WIMPs.

  3. Exclusion limits on the WIMP-nucleon cross section from the cryogenic dark matter search.

    PubMed

    Abusaidi, R; Akerib, D S; Barnes, P D; Bauer, D A; Bolozdynya, A; Brink, P L; Bunker, R; Cabrera, B; Caldwell, D O; Castle, J P; Clarke, R M; Colling, P; Crisler, M B; Cummings, A; Da Silva, A; Davies, A K; Dixon, R; Dougherty, B L; Driscoll, D; Eichblatt, S; Emes, J; Gaitskell, R J; Golwala, S R; Hale, D; Haller, E E; Hellmig, J; Huber, M E; Irwin, K D; Jochum, J; Lipschultz, F P; Lu, A; Mandic, V; Martinis, J M; Nam, S W; Nelson, H; Neuhauser, B; Penn, M J; Perera, T A; Perillo Isaac, M C; Pritychenko, B; Ross, R R; Saab, T; Sadoulet, B; Schnee, R W; Seitz, D N; Shestople, P; Shutt, T; Smith, A; Smith, G W; Sonnenschein, A H; Spadafora, A L; Stockwell, W; Taylor, J D; White, S; Yellin, S; Young, B A

    2000-06-19

    The Cryogenic Dark Matter Search (CDMS) employs Ge and Si detectors to search for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. CDMS data, accounting for the neutron background, give limits on the spin-independent WIMP-nucleon elastic-scattering cross section that exclude unexplored parameter space above 10 GeV/c2 WIMP mass and, at >75% C.L., the entire 3sigma allowed region for the WIMP signal reported by the DAMA experiment. PMID:10991035

  4. Search for pseudoscalar-mediated WIMPs in $t \\rightarrow c$ transitions with missing energy

    E-print Network

    Lian-Bao Jia

    2015-10-01

    The recent astronomical observation of GeV gamma-ray excess from the Galactic Center was suggested due to a $b \\bar{b}$ mode in tens GeV WIMP (weakly interacting massive particle) pair annihilations, and this mode was also explored by the new dwarf galaxy observation. Considering the case the WIMP pair mass below top quark mass, a pseudoscalar $\\phi$ is studied in this article, which mediates the interactions between the standard model fermions and fermionic WIMPs, and neutral flavor-changing interactions in standard model fermion sectors. The $b \\bar{b}$ mode is favored in WIMP pair annihilations, while the WIMP-nucleus scattering is highly suppressed in direct detection. Alternative schemes of $t \\rightarrow c$ decay and single top production are employed to search WIMPs. Assuming the mass of WIMP around 5-60 GeV and with the reasonable inputs by the constraints, the branching ratio $\\mathcal {B}_{t\\rightarrow c \\bar{\\chi} \\chi}$ of a top quark decaying into a charm quark and a WIMP pair is derived of order $10^{-8} - 10^{-5}$, thus careful studies in the future on top-physics may help to gain a better understanding of WIMPs.

  5. Improvement of the Determination of the WIMP Mass from Direct Dark Matter Detection Data

    SciTech Connect

    Drees, Manuel; Shan, Chung-Lin

    2008-11-23

    Weakly Interacting Massive Particles (WIMPs) are one of the leading candidates for Dark Matter. We developed a model--independent method for determining the WIMP mass by using data (i.e., measured recoil energies) of direct detection experiments. Our method is independent of the as yet unknown WIMP density near the Earth, of the form of the WIMP velocity distribution, as well as of the WIMP-nucleus cross section. It requires however positive signals from at least two detectors with different target nuclei. At the first phase of this work we found a systematic deviation of the reconstructed WIMP mass from the real one for heavy WIMPs. Now we improved this method so that this deviation can be strongly reduced for even very high WIMP mass. The statistical error of the reconstructed mass has also been reduced. In a background-free environment, a WIMP mass of {approx}50 GeV could in principle be determined with an error of {approx}35% with only 2x50 events.

  6. Improvement of the Determination of the WIMP Mass from Direct Dark Matter Detection Data

    E-print Network

    Manuel Drees; Chung-Lin Shan

    2008-09-08

    Weakly Interacting Massive Particles (WIMPs) are one of the leading candidates for Dark Matter. We developed a model-independent method for determining the WIMP mass by using data (i.e., measured recoil energies) of direct detection experiments. Our method is independent of the as yet unknown WIMP density near the Earth, of the form of the WIMP velocity distribution, as well as of the WIMP-nucleus cross section. It requires however positive signals from at least two detectors with different target nuclei. At the first phase of this work we found a systematic deviation of the reconstructed WIMP mass from the real one for heavy WIMPs. Now we improved this method so that this deviation can be strongly reduced for even very high WIMP mass. The statistical error of the reconstructed mass has also been reduced. In a background-free evironment, a WIMP mass of ~ 50 GeV could in principle be determined with an error of ~ 35% with only 2 times 50 events.

  7. Correlation between the promoter methylation status of ATP-binding cassette sub-family G member 2 and drug sensitivity in colorectal cancer cell lines.

    PubMed

    Moon, Hyun-Hye; Kim, Sung-Hee; Ku, Ja-Lok

    2016-01-01

    Resistance to chemotherapeutic agents has been considered as a major reason for the high incidence rate of recurrence and metastasis suffered by colorectal cancer (CRC) patients. ATP?binding cassette sub?family G member 2 (ABCG2) is involved in drug resistance. DNA methylation of the ABCG2 promoter site has a significant influence on the regulation of epigenetic gene expression. In the present study, we investigated whether the methylation status of the ABCG2 promoter is related to drug sensitivity in CRC cell lines. In order to examine the ABCG2 expression level and identify the methylation status, RT?PCR, qRT?PCR analysis, MS?PCR and bisulfite sequencing were conducted on 32 CRC cell lines. SNU?C4, LS174T and NCI?H716 were selected as low ABCG2?expressing and high promoter methylated cell lines. The cell proliferation assay for 5?fluorouracil, oxaliplatin and irinotecan was performed after 5?aza?2'?deoxycytidine (5?aza) treatment in these cell lines. In the 32 CRC cell lines, 25% of the cell lines expressed low or no ABCG2 expression. Of these cell lines, SNU?C4, LS174T and NCI?H716 were hypermethylated at the promoter region, ~20%. Demethylation of ABCG2 was induced by 5?aza, which enhanced the ABCG2 expression level and influenced the cell proliferation similar to treatment with the anticancer agents. Our data suggest that the ABCG2 expression level regulated by methylation is related to anticancer drug sensitivity. Based on these results, it can be applied to predict the anticancer drug response. PMID:26497773

  8. Dark matter sensitivity of multi-ton liquid xenon detectors

    E-print Network

    Schumann, Marc; Bütikofer, Lukas; Kish, Alexander; Selvi, Marco

    2015-01-01

    We study the sensitivity of multi ton-scale time projection chambers using a liquid xenon target, e.g., the proposed DARWIN instrument, to spin-independent and spin-dependent WIMP-nucleon scattering interactions. Taking into account realistic backgrounds from the detector itself as well as from neutrinos, we examine the impact of exposure, energy threshold, background rejection efficiency and energy resolution on the dark matter sensitivity. With an exposure of 200 t x y and assuming detector parameters which have been already demonstrated experimentally, spin-independent cross sections as low as $2.5 \\times 10^{-49}$ cm$^2$ can be probed for WIMP masses around 40 GeV/$c^2$. Additional improvements in terms of background rejection and exposure will further increase the sensitivity, while the ultimate WIMP science reach will be limited by neutrinos scattering coherently off the xenon nuclei.

  9. Dark matter sensitivity of multi-ton liquid xenon detectors

    NASA Astrophysics Data System (ADS)

    Schumann, Marc; Baudis, Laura; Bütikofer, Lukas; Kish, Alexander; Selvi, Marco

    2015-10-01

    We study the sensitivity of multi ton-scale time projection chambers using a liquid xenon target, e.g., the proposed DARWIN instrument, to spin-independent and spin-dependent WIMP-nucleon scattering interactions. Taking into account realistic backgrounds from the detector itself as well as from neutrinos, we examine the impact of exposure, energy threshold, background rejection efficiency and energy resolution on the dark matter sensitivity. With an exposure of 200 t × y and assuming detector parameters which have been already demonstrated experimentally, spin-independent cross sections as low as 2.5 × 10?49 cm2 can be probed for WIMP masses around 40 GeV/c2. Additional improvements in terms of background rejection and exposure will further increase the sensitivity, while the ultimate WIMP science reach will be limited by neutrinos scattering coherently off the xenon nuclei.

  10. The development of a sensitive method to study volatile organic compounds in gaseous emissions of lung cancer cell lines 

    E-print Network

    Maroly, Anupam

    2005-08-29

    emissions in selected cancer cell lines and identification of volatile organic compounds (VOCs) in them. Disadvantages of earlier studies were that the measurements were not real time or state specific so that molecular identification was often.............................................................................................................22 Cell line studies......................................................................................................26 Analysis of VOCs...

  11. Light WIMPs, Equivalent Neutrinos, BBN, and the CMB

    E-print Network

    Gary Steigman; Kenneth M. Nollett

    2014-01-21

    Recent updates to the observational determinations of the primordial abundances of helium and deuterium are compared to the predictions of BBN to infer the universal ratio of baryons to photons (or, the present Universe baryon mass density parameter Omega_B h^2), as well as to constrain the effective number of neutrinos (N_eff) and the number of equivalent neutrinos (Delta N_nu). These BBN results are compared to those derived independently from the Planck CMB data. In the absence of a light WIMP (chi), N_eff = 3.05(1 + Delta N_nu/3). In this case, there is excellent agreement between BBN and the CMB, but the joint fit finds that Delta N_nu = 0.40 +/- 0.17, disfavoring standard big bang nucleosynthesis (SBBN: Delta N_nu = 0) at 2.4 sigma, as well as a sterile neutrino (Delta N_nu = 1) at 3.5 sigma. In the presence of a light WIMP, the relation between N_eff and Delta N_nu depends on the WIMP mass, leading to degeneracies among N_eff, Delta N_nu, and m_chi. The complementary and independent BBN and CMB data can break some of these degeneracies. Depending on the nature of the light WIMP (Majorana or Dirac fermion, real or complex scalar) the joint BBN + CMB analyses set a lower bound to m_chi in the range from 0.5 to 5 MeV, and they identify best fit values for m_chi in the range from 5 to 10 MeV. The joint BBN + CMB analyses find a best fit value for the number of equivalent neutrinos, Delta N_nu = 0.65, nearly independent of the nature of the WIMP. The best fit still disfavors the absence of dark radiation (Delta N_nu = 0 at 95% confidence), while allowing for the presence of a sterile neutrino (Delta N_nu = 1 at less than 1 sigma). For all cases considered here, the lithium problem persists. These results, presented at the 2013 Rencontres de l'Observatoire de Paris - ESO Workshop, are based on Nollett & Steigman 2013 (arXiv:1312.5725 [astro-ph.CO]).

  12. Light WIMPs, equivalent neutrinos, BBN, and the CMB

    NASA Astrophysics Data System (ADS)

    Steigman, Gary; Nollett, Kenneth M.

    Recent updates to the observational determinations of the primordial abundances of helium (4He) and deuterium are compared to the predictions of BBN to infer the universal ratio of baryons to photons, eta 10 equiv 1010(n_B/ngamma )0 (or, the present Universe baryon mass density parameter, {?_B h^{2} = eta 10/273.9) as well as to constrain the effective number of neutrinos ({N_eff) and the number of equivalent neutrinos ({?N_?}). These BBN results are compared to those derived independently from the Planck CMB data. In the absence of a light WIMP ({m_?} ? 20 MeV), {N_eff = 3.05(1 + ensuremath {DeltaN_ nu }/3). In this case, there is excellent agreement between BBN and the CMB but, the joint fit reveals that {?N_?} = 0.40±0.17, disfavoring standard big bang nucleosynthesis (SBBN) ({?N_?} = 0) at ˜ 2.4 sigma , as well as a sterile neutrino ({?N_?} = 1) at ˜ 3.5 sigma . In the presence of a light WIMP ({m_?} ? 20 MeV), the relation between {N_eff and {?N_&nu}; depends on the WIMP mass, leading to degeneracies among {N_eff, {?N_?}, and {m_?}. The complementary and independent BBN and CMB data can break some of these degeneracies. Depending on the nature of the light WIMP (Majorana or Dirac fermion, real or complex scalar) the joint BBN + CMB analyses set a lower bound to {m_?} in the range 0.5 - 5 MeV (mchi /me ? 1 - 10) and, they identify best fit values for {m_?} in the range 5 - 10 MeV. The joint BBN + CMB analyses find a best fit value for the number of equivalent neutrinos, {?N_?} ? 0.65, nearly independent of the nature of the WIMP. The best fit still disfavors the absence of dark radiation ({?N_?} = 0 at ˜ 95% confidence), while allowing for the presence of a sterile neutrino ({?N_?} = 1 at ? 1 sigma ). For all cases considered here, the lithium problem persists. These results, presented at the Rencontres de l'Observatoire de Paris 2013 - ESO Workshop and summarized in these proceedings, are based on \\citet{kngs}.

  13. Modulation of sensitivity to cis-diamminedichloroplatinum (II) by thromboxane A2 receptor antagonists in non-small-cell lung cancer cell lines.

    PubMed Central

    Kasahara, K.; Fujimura, M.; Bando, T.; Shibata, K.; Shirasaki, H.; Matsuda, T.

    1996-01-01

    We examined the effect of selective thromboxane A2 (TXA2) receptor antagonists, calcium 5(Z)-1R, 2S, 3S, 4S-7-[3-phenylsulphonylaminobicyclo [2.2.1] hept-2-yl]-5-heptonoate hydrate (S-1452) and +/- -7-(3,5,6,-trimethyl-1,4-benzoquinon-2-yl)-7-phenylhaptanoic acid (AA-2414), on sensitivity to cis-diamminedichloroplatinum (II) (CDDP) in non-small-cell lung cancer cell lines. IC50 values to CDDP using MTT assay were decreased 2.1- and 4.6-fold respectively by treatment with 250 or 500 microM S-1452, for a 2 h simultaneous drug exposure, and those of PC-9/CDDP, a CDDP-resistant cell line, were decreased 3.1- and 6.1-fold. Sensitivity to carboplatin was also enhanced by the treatment with S-1452. IC50 values to CDDP and carboplatin were decreased by treatment with AA-2414 in a dose-dependent manner. Isobologram analysis showed that the combination of CDDP with S-1452 or AA-2414 produced supra-additive or additive effects in each cell line. Neither glutathione content nor glutathione S-transferase activity was changed in either cell line by treatment with 500 microM S-1452. Accumulation of platinum into PC-9 and PC-9/CDDP was increased by the treatment in a dose-dependent manner. Na+, K+-ATPase activity of PC-9 and PC-9/CDDP was enhanced by the treatment of S-1452 in a dose-dependent manner. These data show that the TXA2 receptor antagonists may enhance the sensitivity of non-small-cell lung cancer cell lines to platinum agents. Increase in Na+, K+-ATPase activity induced by S-1452 may be the mechanism of its sensitising effect through increase in platinum accumulation. PMID:8932334

  14. Modulation of sensitivity to cis-diamminedichloroplatinum (II) by thromboxane A2 receptor antagonists in non-small-cell lung cancer cell lines.

    PubMed

    Kasahara, K; Fujimura, M; Bando, T; Shibata, K; Shirasaki, H; Matsuda, T

    1996-11-01

    We examined the effect of selective thromboxane A2 (TXA2) receptor antagonists, calcium 5(Z)-1R, 2S, 3S, 4S-7-[3-phenylsulphonylaminobicyclo [2.2.1] hept-2-yl]-5-heptonoate hydrate (S-1452) and +/- -7-(3,5,6,-trimethyl-1,4-benzoquinon-2-yl)-7-phenylhaptanoic acid (AA-2414), on sensitivity to cis-diamminedichloroplatinum (II) (CDDP) in non-small-cell lung cancer cell lines. IC50 values to CDDP using MTT assay were decreased 2.1- and 4.6-fold respectively by treatment with 250 or 500 microM S-1452, for a 2 h simultaneous drug exposure, and those of PC-9/CDDP, a CDDP-resistant cell line, were decreased 3.1- and 6.1-fold. Sensitivity to carboplatin was also enhanced by the treatment with S-1452. IC50 values to CDDP and carboplatin were decreased by treatment with AA-2414 in a dose-dependent manner. Isobologram analysis showed that the combination of CDDP with S-1452 or AA-2414 produced supra-additive or additive effects in each cell line. Neither glutathione content nor glutathione S-transferase activity was changed in either cell line by treatment with 500 microM S-1452. Accumulation of platinum into PC-9 and PC-9/CDDP was increased by the treatment in a dose-dependent manner. Na+, K+-ATPase activity of PC-9 and PC-9/CDDP was enhanced by the treatment of S-1452 in a dose-dependent manner. These data show that the TXA2 receptor antagonists may enhance the sensitivity of non-small-cell lung cancer cell lines to platinum agents. Increase in Na+, K+-ATPase activity induced by S-1452 may be the mechanism of its sensitising effect through increase in platinum accumulation. PMID:8932334

  15. Suppression of a DNA base excision repair gene, hOGG1, increases bleomycin sensitivity of human lung cancer cell line

    SciTech Connect

    Wu Mei; Zhang Zunzhen Che Wangjun

    2008-05-01

    Bleomycin (BLM) has been found to induce 8-oxoguanine and DNA strand breaks through producing oxidative free radicals, thereby leading to cell cycle arrest, apoptosis and cell death. Cellular DNA damage repair mechanisms such as single strand DNA break repair/base excision repair (BER) are responsible for removing bleomycin-induced DNA damage, therefore confer chemotherapeutic resistance to bleomycin. In this study, we have investigated if down-regulation of human 8-oxoguanine DNA glycosylase (hOGG1), an important BER enzyme, could alter cellular sensitivity to bleomycin, thereby reducing chemotherapeutic resistance in human tumor cell. A human lung cancer cell line with hOGG1 deficiency (A549-R) was created by ribozyme gene knockdown technique. Bleomycin cellular sensitivity and DNA/chromosomal damages were examined using MTT, colony forming assay, comet assay as well as micronucleus assay. We demonstrated that hOGG1 gene knockdown enhanced bleomycin cytotoxicity and reduced the ability of colony formation of the lung cancer cell lines. We further demonstrated that bleomycin-induced DNA strand breaks resulted in an increase of micronucleus rate. hOGG1 deficiency significantly reduced DNA damage repair capacity of the lung cancer cell lines. Our results indicated that hOGG1 deficiency allowed the accumulation of bleomycin-induced DNA damage and chromosomal breaks by compromising DNA damage repair capacity, thereby increasing cellular sensitivity to bleomycin.

  16. The transformation of the photo-thermo sensitive genic male-sterile line 261S of rice via an expression vector containing the anti-Waxy gene

    PubMed Central

    Yang, Rui; Zhou, Yongguo; Cao, Yueqin; Yin, Zhongming; Yang, Lijun; Li, Jianyue

    2013-01-01

    Transgenic photo-thermo sensitive genic male sterility Oryza sativa L. cv. “261S” plants with the anti-Waxy gene were successfully obtained using an Agrobacterium tumefaciens-mediated co-transformation method. Marker-free homozygous transgenic lines with the anti-Waxy gene were obtained. The setting seed rates of the transgenic plants via self-pollination or via crossing with the restorer line WX99075 rice and the 1000-grain weight of the transgenic plants and the F2 hybrid seeds obtained by crossing the transgenic or non-transgenic plants with the restorer line WX99075 rice, and the number of panicles of the transgenic plants and yields of the F2 hybrid rice, were analysed. Quality indexes of the transgenic plants and of the F2 hybrid seeds were analysed. Our researches results indicate that hybrid female and hybrid descendant edibility could be improved via the introduction of the anti-Waxy gene, but the grain yields of the reserve seeds via self-pollination of the transgenic photo-thermo sensitive genic sterile lines and of the hybrid rice were not affected. PMID:23853508

  17. Evaluation of the neutron background in cryogenic Germanium target for WIMP direct detection when using a reactor neutrino detector as a neutron veto system

    E-print Network

    Ye Xu; Jieqin Lan; Yin Bai; Weiwei Gao

    2015-12-03

    A direct WIMP (Weakly Interacting Massive Particle) detector with a neutron veto system is designed to better reject neutrons. An experimental configuration is studied in the present paper: 984 Ge modules are placed inside a reactor neutrino detector. In order to discriminate between nuclear and electron recoil, both ionization and heat signatures are measured using cryogenic germanium detectors in this detection. The neutrino detector is used as a neutron veto device.The neutron background for the experimental design has been estimated using the Geant4 simulation. The results show that the neutron background can decrease to O(0.01) events per year per tonne of high purity Germanium. We calculate the sensitivity to spin-independent WIMP-nucleon elastic scattering. An exposure of one tonne $\\times$ year could reach a cross-section of about 2$\\times$$10^{-11}$ pb.

  18. Evaluation of the neutron background in a direct WIMP detector with neutron veto system based on Gd-doped liquid scintillator

    SciTech Connect

    Xu, Ye; Ji, XiangPan; Liu, ZeLong; Di, DanNing; Sun, HaoKai; Lei, Yu E-mail: jixiangpan@mail.nankai.edu.cn E-mail: ditan1111@mail.nankai.edu.cn E-mail: mr.yu.lei@gmail.com

    2011-06-01

    A direct WIMP (Weakly Interacting Massive Particle) detector with a neutron veto system is designed to better reject neutrons. Two experimental configurations are studied in the present paper: one is for an Xe detector enclosed in a Gd-loaded scintillator and the other one is for an Xe detector placed inside a reactor neutrino detector. The Gd-doped liquid scintillator (or the neutrino detector) is used as a neutron veto device. The neutron backgrounds for the two experimental designs have been estimated using Geant4 simulations. The results show that the neutron backgrounds can decrease to O(0.1) events per year per tonne of liquid Xenon. We calculate the sensitivities to spin-independent WIMP-nucleon elastic scattering. An exposure of one tonne × year could reach a cross-section of about 6 × 10{sup ?11} pb.

  19. WIMP diffusion in the solar system including solar depletion and its effect on Earth capture rates

    E-print Network

    Johan Lundberg; Joakim Edsjo

    2004-01-08

    Weakly Interacting Massive Particles (WIMPs) can be captured by the Earth, where they eventually sink to the core, annihilate and produce e.g. neutrinos that can be searched for with neutrino telescopes. The Earth is believed to capture WIMPs not dominantly from the Milky Way halo directly, but instead from a distribution of WIMPs that have diffused around in the solar system due to gravitational interactions with the planets in the solar system. Recently, doubts have been raised about the lifetime of these WIMP orbits due to solar capture. We here investigate this issue by detailed numerical simulations. Compared to earlier estimates, we find that the WIMP velocity distribution is significantly suppressed below about 70 km/s which results in a suppression of the capture rates mainly for heavier WIMPs (above ~100 GeV). At 1 TeV and above the reduction is almost a factor of 10. We apply these results to the case where the WIMP is a supersymmetric neutralino and find that, within the Minimal Supersymmetric Standard Model (MSSM), the annihilation rates, and thus the neutrino fluxes, are reduced even more than the capture rates. At high masses (above ~1 TeV), the suppression is almost two orders of magnitude. This suppression will make the detection of neutrinos from heavy WIMP annihilations in the Earth much harder compared to earlier estimates.

  20. Reconstructing the Velocity Distribution of WIMPs from Direct Dark Matter Detection Data

    E-print Network

    Manuel Drees; Chung-Lin Shan

    2007-06-01

    Weakly interacting massive particles (WIMPs) are one of the leading candidates for dark matter. Currently, the most promising method to detect many different WIMP candidates is the direct detection of the recoil energy deposited in a low-background laboratory detector due to elastic WIMP-nucleus scattering. So far the usual procedure has been to predict the event rate of direct detection of WIMPs based on some model(s) of the galactic halo. The aim of our work is to invert this process. That is, we study what future direct detection experiment can teach us about the WIMP halo. As the first step we consider a time-averaged recoil spectrum, assuming that no directional information exists. We develop a method to construct the (time-averaged) one-dimensional velocity distribution function from this spectrum. Moments of this function, such as the mean velocity and velocity dispersion of WIMPs, can also be obtained directly from the recoil spectrum. The only input needed in addition to a measured recoil spectrum is the mass of the WIMP; no information about the scattering cross section or WIMP density is required.

  1. CMB constraints on the thermal WIMP mass and annihilation cross section

    NASA Astrophysics Data System (ADS)

    Steigman, Gary

    2015-04-01

    A thermal relic, often referred to as a weakly interacting massive particle (WIMP), is a particle produced during the early evolution of the Universe whose present (relic) abundance depends only on its mass and its thermally averaged annihilation cross section (annihilation rate factor) ?? v ?ann . Late time WIMP annihilation has the potential to affect the cosmic microwave background (CMB) power spectrum. Current observational constraints on the absence of such effects provide bounds on the mass and the annihilation cross section of relic particles that may be, but need not be, dark matter candidates. For a WIMP that is a dark matter candidate, the CMB constraint sets an upper bound to the annihilation cross section, leading to a lower bound to its mass that depends on whether or not the WIMP is its own antiparticle. For a self-conjugate WIMP, mmin=50 f GeV , where f ?1 is an electromagnetic energy efficiency factor. For a non-self-conjugate WIMP, the minimum mass is a factor of two larger. For a WIMP that is a subdominant component of the dark matter density there is no bound on its mass and the upper bound to its annihilation cross section imposed by the CMB transforms into a lower bound to its annihilation cross section. These results are outlined and quantified here using the latest CMB constraints for a stable, symmetric (equal number of particles and antiparticles), WIMP whose annihilation is s-wave dominated, and for particles that are, or are not, their own antiparticle.

  2. Study of capture and annihilation of a few GeV WIMPs inside the Sun by using an underground

    E-print Network

    Tokyo, University of

    Study of capture and annihilation of a few GeV WIMPs inside the Sun by using an underground in the universe. Weakly interacting massive particles (WIMPs) are favored as parti- cle candidates for non such as DAMA/LIBRA, CoGeNT, CRESST and CDMS II Si would suggest possible evidence for WIMPs with light masses

  3. Exclusion Limits on the WIMP-Nucleon Elastic-Scattering Cross Section from the Cryogenic Dark Matter Search

    E-print Network

    California at Berkeley, University of

    Exclusion Limits on the WIMP-Nucleon Elastic-Scattering Cross Section from the Cryogenic Dark Date Date Date University of California at Berkeley Fall 2000 #12;Exclusion Limits on the WIMP Ramanlal Golwala #12;1 Abstract Exclusion Limits on the WIMP-Nucleon Elastic-Scattering Cross Section from

  4. EXCLUSION LIMITS ON THE WIMP-NUCLEON SCATTERING CROSS-SECTION FROM THE CRYOGENIC DARK MATTER SEARCH

    E-print Network

    California at Berkeley, University of

    EXCLUSION LIMITS ON THE WIMP-NUCLEON SCATTERING CROSS-SECTION FROM THE CRYOGENIC DARK MATTER SEARCH Search (CDMS) employs massive ionization- and phonon-mediated detectors to search for WIMPs via particles. Limits on the WIMP-nucleon scattering cross-section, based on 3.1 kg d of exposure, exclude new

  5. Reconfigurable and ultra-sensitive in-line Mach-Zehnder interferometer based on the fusion of microfiber and microfluid

    NASA Astrophysics Data System (ADS)

    Gao, Shecheng; Zhang, Weigang; Zhang, Hao; Zhang, Chonglei

    2015-02-01

    A reconfigurable Mach-Zenhnder interferometer (MZI) based on a microfluidic cavity (MFC) constructed by embedding a microfiber between two segments of single-mode fibers with pre-designed lateral offset has been proposed and experimentally demonstrated. The MFC serves as an interference arm with an eccentric annular cross section and allows convenient sample (gas or liquids) replacement procedure. The microfiber works as the other interference arm that provides the proposed device with ease of reconstruction and also enhances the force sensitivity. The re-configurability and the ultra-wide tuning sensitivity range are demonstrated by immersing the MZI constructed with a 484 ?m-long-MFC and a microfiber 44 ?m in diameter in different droplets. Ultrahigh sensitivities of 34.65 nm/°C (˜88 380 nm/RIU) and -493.7 nm/N (˜-590 pm/??) are experimentally achieved using a droplet with a refractive index of ˜1.44.

  6. Dark matter search by exclusive studies of X-rays following WIMPs nuclear interactions

    E-print Network

    H. Ejiri; Ch. C. Moustakidis; J. D. Vergados

    2006-03-14

    It is shown that weakly interacting massive particles (WIMPs), which are possible cold dark matter candidates, can be studied by exclusive measurements of X-rays following WIMPs nuclear interactions. Inner-shell atomic electrons are ionized through WIMP-nuclear interaction, and then mono-energetic X-rays are emitted when they are filled by outer-shell electrons. The number of inner-shell holes amounts to as large as one per five nuclear recoils for K-shell and several per recoil for L-shell in the case of medium heavy target nuclei interacting with 100-300 GeV WIMPs. Then the K and L X-ray peaks show up in the 5-50 keV region. Consequently exclusive studies of the X-rays in coincidence with the nuclear recoils and the ionization electrons are found to provide excellent opportunities to detect WIMPs such as the Lightest Super Symmetric Particles (LSP)

  7. Search for pseudoscalar-mediated WIMPs in $t \\rightarrow c$ transitions with missing energy

    E-print Network

    Jia, Lian-Bao

    2015-01-01

    The recent astronomical observation confirms a spatially extended excess of $\\sim$1-3 GeV gamma rays from the region surrounding the Galactic Center, and it is suggested that the excess is due to dark matter, e.g. WIMPs (weakly interacting massive particles) of $35\\sim 51$ GeV annihilating to $b\\bar b$ pairs. Inevitably, models about WIMPs must undergo the tests of astronomical observation, accelerator and direct detection. In this work, considering the pseudoscalar-mediated WIMP model and assuming the mass of WIMP around 5-60 GeV, we suggest to test the model in the $t\\to c$ decays with missing energy. With the reasonable inputs, the branching ratio $\\mathcal {B}_{t\\rightarrow c \\bar{\\chi} \\chi}$ is derived of order $10^{-8} - 10^{-6}$, thus careful studies in the future on top-physics may help to gain a better understanding of WIMPs.

  8. Research paper citation record keeping: it is not for wimps.

    PubMed

    Dodson, M V

    2008-10-01

    In an era in which academic institutions are held more accountable, a problem, which does not seem to have an immediate resolution, exists: how does one demonstrate the quality of one's work? Specifically, how does one show that his or her research is making an impact and is thought to be important? A variety of measures of scientific journal article importance, reflected mostly by citation analyses, have been focused on as being potential gold standards. However, although several measures have been reported, keeping a record of citation of individual research papers, primarily due to the effort involved in finding accurate information, is not for wimps. PMID:18502875

  9. Higgs Bosons and the Indirect Search for WIMPs

    E-print Network

    V. A. Bednyakov; H. V. Klapdor-Kleingrothaus; H. Tu

    2001-01-19

    We investigated the contribution of the MSSM Higgs bosons produced in the neutralino annihilation in the Earth and Sun to the total WIMPs detection signals. We found that this contribution is very important and results in a lower bound for the muon flux from the Sun of 10^{-7} - 10^{-8} m^{-2} yr^{-1} for neutralinos heavier than 200 GeV. We noticed that due to the SUSY charged Higgs bosons one can expect an energetic tau neutrino flux from the Sun at a level of 10^2 m^{-2} yr^{-1}.

  10. Sensitivity of Idealized Squall-Line Simulations to the Level of Complexity Used in Two-Moment Bulk Microphysics Schemes

    E-print Network

    the latent heat associated with it drives atmospheric circulations. It is also associated with the most York HUGH MORRISON National Center for Atmospheric Research,* Boulder, Colorado JASON A. MILBRANDT with deep convection. To do so, the sensitivity of surface precipitation is evaluated in two

  11. The Sensitivity of Tropical Squall Lines (GATE and TOGA COARE) to Surface Fluxes: Cloud Resolving Model Simulations

    NASA Technical Reports Server (NTRS)

    Wang, Yansen; Tao, Wei-Kuo; Simpson, Joanne; Lang, Stephen

    1999-01-01

    Two tropical squall lines from TOGA COARE and GATE were simulated using a two-dimensional cloud-resolving model to examine the impact of surface fluxes on tropical squall line development and associated precipitation processes. The important question of how CAPE in clear and cloudy areas is maintained in the tropics is also investigated. Although the cloud structure and precipitation intensity are different between the TOGA COARE and GATE squall line cases, the effects of the surface fluxes on the amount of rainfall and on the cloud development processes are quite similar. The simulated total surface rainfall amount in the runs without surface fluxes is about 67% of the rainfall simulated with surface fluxes. The area where surface fluxes originated was categorized into clear and cloudy regions according to whether there was cloud in the vertical column. The model results indicated that the surface fluxes from the large clear air environment are the dominant moisture source for tropical squall line development even though the surface fluxes in the cloud region display a large peak. The high-energy air from the boundary layer in the clear area is what feeds the convection while the CAPE is removed by the convection. The surface rainfall was only reduced 8 to 9% percent in the simulations without surface fluxes in the cloud region. Trajectory and water budget analysis also indicated that most moisture (92%) was from the boundary layer of the clear air environment.

  12. A Search for WIMP Dark Matter using an Optimized Chi-square Technique on the Final Data from the Cryogenic Dark Matter Search Experiment (CDMS II)

    NASA Astrophysics Data System (ADS)

    Manungu Kiveni, Joseph

    2012-06-01

    During the last two decades, cosmology has become a precision observational science thanks (in part) to the incredible number of experiments performed to better understand the composition of the universe. The large amount of data accumulated strongly indicates that the bulk of the universe's matter is in the form of non-baryonic matter that does not interact electromagnetically. Combined evidence from the dynamics of galaxies and galaxy clusters confirms that most of the mass in the universe is not composed of any known form of matter. Measurements of the cosmic microwave background, big bang nucleosynthesis and many other experiments indicate that ˜80% of the matter in the universe is dark, non-relativistic and cold. The dark matter resides in the halos surrounding galaxies, galaxy clusters and other large-scale structures. Weakly Interacting Massive Particles (WIMPs) are well motivated class of dark matter candidates that arise naturally in supersymmetric extensions to the Standard Model of particles physics, and can be produced as non-relativistic thermal relics in the early universe with about the right density to account for the missing mass. The Cryogenic Dark Matter Search (CDMS) experiment seeks to directly detect the keV-scale energy deposited by WIMPs in the galactic halo when they scatter from nuclei in the crystalline detectors made of germanium and silicon. These detectors, called Z-sensitive Ionization and Phonon detectors (ZIPs) are operated at ˜ 45 mK and simultaneously measure the ionization and the (athermal) phonons produced by particle interactions. The ratio of ionization and phonon energies allows discrimination of a low rate of nuclear recoils (expected for WIMPs) from an overwhelming rate of electron recoils (expected for most backgrounds). Phonon-pulse shape and timing enables further suppression of lower-rate interactions at the detector surfaces. This dissertation describes the results of a WIMP search using CDMS II data sets accumulated at the Soudan Underground Laboratory in Minnesota. Results from the original analysis of these data were published in 2009; two events were observed in the signal region with an expected leakage of 0.9 events. Further investigation revealed an issue with the ionization-pulse reconstruction algorithm leading to a software upgrade and a subsequent reanalysis of the data. As part of the reanalysis, I performed an advanced discrimination technique to better distinguish (potential) signal events from backgrounds using a 5-dimensional chi-square method. This data-analysis technique combines the event information recorded for each WIMP-search event to derive a background-discrimination parameter capable of reducing the expected background to less than one event, while maintaining high efficiency for signal events. Furthermore, optimizing the cut positions of this 5-dimensional chi-square parameter for the 14 viable germanium detectors yields an improved expected sensitivity to WIMP interactions relative to previous CDMS results. This dissertation describes my improved (and optimized) discrimination technique and the results obtained from a blind application to the reanalyzed CDMS II WIMP-search data. This analysis achieved the best expected sensitivity of the three techniques developed for the reanalysis and so was chosen as the primary timing analysis whose limit will be quoted in a on-going publication paper which is currently in preparation. For this analysis, a total raw exposure of 612.17 kg-days are analyzed for this work. No candidate events was observed, and a corresponding upper limit on the WIMP-nucleon scattering cross section as a function of WIMP mass is defined. These data set a 90% upper limit on spin-independent WIMP-nucleon elastic-scattering cross section of 3.19 × 10-44 cm2 for a WIMP mass of 60 GeV c 2. Combining this result with all previous CDMS II data gives an upper limit of 1.96 ×10-44 cm2 for a WIMP of mass 60 GeV/c2 (a factor of 2 better than the original analysis). At the moment this analysis is being written, the WIMP-search results ob

  13. Extended Source Gamma-Ray Emission from WIMP Annihilation in the Sagittarius Dwarf Elliptical Galaxy (SULI paper)

    SciTech Connect

    Vasu-Devan, Vidya; /Columbia U. /SLAC

    2006-01-04

    The proximity of the dark matter dominated Sagittarius Dwarf Elliptical Galaxy (position (l,b) = 5.6{sup o}, -14{sup o}) allows it to act as an ideal laboratory for the exploration of extended gamma-ray emission from Weakly Interacting Massive Particle (WIMP) annihilation processes in a dark matter-dominated system. Since the matter in our universe is predominantly dark, exploring such processes as WIMP annihilation will lead to a better understanding of cosmology. In order to study this gamma-ray emission, a model for the diffuse background gamma-radiation in the dwarf galaxy's region is extracted from the Energetic Gamma Ray Experiment Telescope (EGRET) data. After validating this model and comparing it to the EGRET diffuse model, the background model is added to effective bleeding-contamination from external point sources and multiple models for the signal-above-background emission. Various models of this emission are tested: (a) no source located in region, (b) unidentified point source 3EG J1847-3219 from the Third EGRET Catalog responsible for the emission and (c) extended emission resulting from WIMP annihilation responsible for the signal above background. These models are created through the employment of Monte Carlo simulation methods, utilizing the response functions of the EGRET instrument to simulate the point spread function, energy dispersion and effects of variable effective area depending on angle of incidence. Energy spectra for point sources are generated from the best predictions of spectral indices listed in the Third EGRET Catalog and the spectrum for the extended dark matter source is generated from Pythia high energy annihilation simulations. Hypothesis testing is conducted to assess the goodness-of-fit of these models to the data taken by EGRET. Additionally, we hope to expand our analysis by employing the response functions of the imminent Gamma Ray Large Area Space Telescope (GLAST) to our models. This extension should highlight the sensitivity disparities between GLAST and EGRET and show GLAST's potential enhancement of this analysis. This process will allow for forecasting of extended WIMP annihilation emission signatures for the GLAST detector.

  14. Extremely sensitive detection of NO? employing off-axis integrated cavity output spectroscopy coupled with multiple-line integrated absorption spectroscopy.

    PubMed

    Rao, Gottipaty N; Karpf, Andreas

    2011-05-01

    We report on the development of a new sensor for NO? with ultrahigh sensitivity of detection. This has been accomplished by combining off-axis integrated cavity output spectroscopy (OA-ICOS) (which can provide large path lengths of the order of several kilometers in a small volume cell) with multiple-line integrated absorption spectroscopy (MLIAS) (where we integrate the absorption spectra over a large number of rotational-vibrational transitions of the molecular species to further improve the sensitivity). Employing an external cavity quantum cascade laser operating in the 1601-1670 cm?¹ range and a high-finesse optical cavity, the absorption spectra of NO? over 100 transitions in the R band have been recorded. From the observed linear relationship between the integrated absorption versus concentration of NO? and the standard deviation of the integrated absorption signal, we report an effective sensitivity of detection of approximately 28 ppt (parts in 10¹²) for NO? To the best of our knowledge, this is among the most sensitive levels of detection of NO? to date. PMID:21532674

  15. Lymphoblastoid lines and skin fibroblasts from patients with tuberous sclerosis are abnormally sensitive to ionizing radiation and to a radiomimetic chemical

    SciTech Connect

    Scudiero, D.A.; Moshell, A.N.; Scarpinato, R.G.; Meyer, S.A.; Clatterbuck, B.E.; Tarone, R.E.; Robbins, J.H.

    1982-03-01

    Lymphoblastoid lines, derived by transforming peripheral blood lymphocytes with Epstein-Barr virus, and skin fibroblast lines were established from two patients with tuberous sclerosis. The number of viable lymphoblastoid cells was determined by their ability to exclude the vital dye trypan blue after their irradiation with x-rays or 254 nm ultraviolet light. The growth of fibroblasts was determined by their ability to form colonies after treatment with the radiomimetic, DNA-damaging chemical N-methyl-N'-nitro-N-nitrosoguanidine. The tuberous sclerosis lymphoblastoid lines were hypersensitive to x-rays but had normal sensitivity to the ultraviolet radiation. The tuberous sclerosis fibroblast lines were hypersensitive to the N-methyl-N'-nitro-N-nitrosoguanidine. The hypersensitivity of tuberous sclerosis cells to x-rays and to N-methyl-N'-nitro-N-nitrosoguanidine is believed to reflect defective repair of DNA damaged by these agents and may provide the basis for in vitro, including prenatal, diagnostic tests for tuberous sclerosis.

  16. Antrodia cinnamomea alleviates cisplatin-induced hepatotoxicity and enhances chemo-sensitivity of line-1 lung carcinoma xenografted in BALB/cByJ mice.

    PubMed

    Huang, Tse-Hung; Chiu, Yi-Han; Chan, Yi-Lin; Wang, Hang; Li, Tsung-Lin; Liu, Chien-Yin; Yang, Cheng-Ta; Lee, Tzung-Yan; You, Jyh-Sheng; Hsu, Kuang-Hung; Wu, Chang-Jer

    2015-09-22

    Whereas cisplatin (cis-diamminedichloroplatinum II) is a first-line medicine to treat solid cancerous tumors, it often causes serious side effects. New medicines that have an equivalent or even better therapeutic effect but with free or less side effects than cisplatin are highly anticipated in cancer therapy. Recent reports revealed that Antrodia cinnamomea (AC) possesses hepatoprotective activity in addition to anticancer. In this study, we wanted to know whether AC enhances chemo-sensitivity of cisplatin and/or alleviates cisplatin-induced hepatotoxicity, as well as the underlying mechanisms thereof. Our results indicated that AC inhibited proliferation of line-1 lung carcinoma cells and rescued hepatic HepG2 cells from cisplatin-induced cell death in vitro. The fact is that AC and cisplatin synergized to constrain growth of line-1 lung carcinoma cells in BALB/cByJ mice. Quantitative real-time PCR further revealed that AC promoted expression of apoptosis-related genes, while it decreased expression of NF-?B and VEGF in tumor tissues. In liver, AC reduced cisplatin-induced liver dysfunctions, liver inflammation and hepatic apoptosis in addition to body weight restoration. In summary, AC is able to increase cisplatin efficacy by triggering expression of apoptosis-related genes in line-1 lung cancer cells as well as to protect liver from tissue damage by avoiding cisplatin-induced hepatic inflammation and cell death. PMID:26325335

  17. Fibulin-3 negatively regulates ALDH1 via c-MET suppression and increases ?-radiation-induced sensitivity in some pancreatic cancer cell lines

    SciTech Connect

    Kim, In-Gyu; Lee, Jae-Ha; Kim, Seo-Yoen; Kim, Jeong-Yul; Cho, Eun-Wie

    2014-11-21

    Highlights: • FBLN-3 gene was poorly expressed in some pancreatic cancer lines. • FBLN-3 promoter region was highly methylated in some pancreatic cancer cell lines. • FBLN-3 inhibited c-MET activation and expression and reduced cellular level of ALDH1. • FBLN-3/c-Met/ALDH1 axis modulates stemness and EMT in pancreatic cancer cells. - Abstract: Fibulin-3 (FBLN-3) has been postulated to be either a tumor suppressor or promoter depending on the cell type, and hypermethylation of the FBLN-3 promoter is often associated with human disease, especially cancer. We report that the promoter region of the FBLN-3 was significantly methylated (>95%) in some pancreatic cancer cell lines and thus FBLN-3 was poorly expressed in pancreatic cancer cell lines such as AsPC-1 and MiaPaCa-2. FBLN-3 overexpression significantly down-regulated the cellular level of c-MET and inhibited hepatocyte growth factor-induced c-MET activation, which were closely associated with ?-radiation resistance of cancer cells. Moreover, we also showed that c-MET suppression or inactivation decreased the cellular level of ALDH1 isozymes (ALDH1A1 or ALDH1A3), which serve as cancer stem cell markers, and subsequently induced inhibition of cell growth in pancreatic cancer cells. Therefore, forced overexpression of FBLN-3 sensitized cells to cytotoxic agents such as ?-radiation and strongly inhibited the stemness and epithelial to mesenchymal transition (EMT) property of pancreatic cancer cells. On the other hand, if FBLN3 was suppressed in FBLN-3-expressing BxPC3 cells, the results were opposite. This study provides the first demonstration that the FBLN-3/c-MET/ALDH1 axis in pancreatic cancer cells partially modulates stemness and EMT as well as sensitization of cells to the detrimental effects of ?-radiation.

  18. Potentially large one-loop corrections to WIMP annihilation

    SciTech Connect

    Drees, M.; Kim, J. M.; Nagao, K. I.

    2010-05-15

    We compute one-loop corrections to the annihilation of nonrelativistic particles {chi} due to the exchange of a (gauge or Higgs) boson {phi} with mass {mu} in the initial state. In the limit m{sub {chi}>}>{mu} this leads to the 'Sommerfeld enhancement' of the annihilation cross section. However, here we are interested in the case {mu} < or approx. m{sub {chi},} where the one-loop corrections are well behaved, but can still be sizable. We find simple and accurate expressions for annihilation from both S- and P-wave initial states; they differ from each other if {mu}{ne}0. In order to apply our results to the calculation of the relic density of weakly interacting massive particles (WIMPs), we describe how to compute the thermal average of the corrected cross sections. We apply this formalism to scalar and Dirac fermion singlet WIMPs, and show that the corrections are always very small in the former case, but can be very large in the latter. Moreover, in the context of the minimal supersymmetric standard model, these corrections can decrease the relic density of neutralinos by more than 1%, if the lightest neutralino is a strongly mixed state.

  19. Shedding Light on the Dark Sector with Direct WIMP Production

    E-print Network

    Partha Konar; Kyoungchul Kong; Konstantin T. Matchev; Maxim Perelstein

    2009-04-28

    A Weakly Interacting Massive Particle (WIMP) provides an attractive dark matter candidate, and should be within reach of the next generation of high-energy colliders. We consider the process of direct WIMP pair-production, accompanied by an initial-state radiation photon, in electron-positron collisions at the proposed International Linear Collider (ILC). We present a parametrization of the differential cross section for this process which conveniently separates the model-independent information provided by cosmology from the model-dependent inputs from particle physics. As an application, we consider two simple models, one supersymmetric, and another of the "universal extra dimensions" (UED) type. The discovery reach of the ILC and the expected precision of parameter measurements are studied in each model. In addition, for each of the two examples, we also investigate the ability of the ILC to distinguish between the two models through a shape-discrimination analysis of the photon energy spectrum. We show that with sufficient beam polarization the alternative model interpretation can be ruled out in a large part of the relevant parameter space.

  20. Dark matter in the Solar System. III. The distribution function of WIMPs at the Earth from gravitational capture

    SciTech Connect

    Peter, Annika H. G.

    2009-05-15

    In this last paper in a series of three on weakly interacting massive particle (WIMP) dark matter in the Solar System, we focus on WIMPs bound to the system by gravitationally scattering off of planets. We present simulations of WIMP orbits in a toy solar system consisting of only the Sun and Jupiter. As previous work suggested, we find that the density of gravitationally captured WIMPs at the Earth is small and largely insensitive to the details of elastic scattering in the Sun. However, we find that the density of gravitationally captured WIMPs may be affected by external Galactic gravitational fields. If such fields are unimportant, the density of gravitationally captured WIMPs at the Earth should be similar to the maximum density of WIMPs captured in the Solar System by elastic scattering in the Sun. Using standard assumptions about the halo WIMP distribution function, we find that the gravitationally captured WIMPs contribute negligibly to direct detection event rates. While these WIMPs do dominate the annihilation rate of WIMPs in the Earth, the resulting event rate in neutrino telescopes is too low to be observed in next-generation neutrino telescopes.

  1. Dark matter in the solar system III: The distribution function of WIMPs at the Earth from gravitational capture

    E-print Network

    Annika H. G. Peter

    2009-02-09

    In this last paper in a series of three on weakly interacting massive particle (WIMP) dark matter in the solar system, we focus on WIMPs bound to the system by gravitationally scattering off of planets. We present simulations of WIMP orbits in a toy solar system consisting of only the Sun and Jupiter. As previous work suggested, we find that the density of gravitationally captured WIMPs at the Earth is small and largely insensitive to the details of elastic scattering in the Sun. However, we find that the density of gravitationally captured WIMPs may be affected by external Galactic gravitational fields. If such fields are unimportant, the density of gravitationally captured WIMPs at the Earth should be similar to the maximum density of WIMPs captured in the solar system by elastic scattering in the Sun. Using standard assumptions about the halo WIMP distribution function, we find that the gravitationally captured WIMPs contribute negligibly to direct detection event rates. While these WIMPs do dominate the annihilation rate of WIMPs in the Earth, the resulting event rate in neutrino telescopes is too low to be observed in next-generation neutrino telescopes.

  2. Evaluation of the sensitizing potential of antibiotics in vitro using the human cell lines THP-1 and MUTZ-LC and primary monocyte?derived dendritic cells

    SciTech Connect

    Sebastian, Katrin; Ott, Hagen; Zwadlo-Klarwasser, Gabriele; Skazik-Voogt, Claudia; Marquardt, Yvonne; Czaja, Katharina; Merk, Hans F.; Baron, Jens Malte

    2012-08-01

    Since the 7th amendment to the EU cosmetics directive foresees a complete ban on animal testing, alternative in vitro methods have been established to evaluate the sensitizing potential of small molecular weight compounds. To find out whether these novel in vitro assays are also capable to predict the sensitizing potential of small molecular weight drugs, model compounds such as beta-lactams and sulfonamides – which are the most frequent cause of adverse drug reactions – were co-incubated with THP-1, MUTZ-LC, or primary monocyte?derived dendritic cells for 48 h and subsequent expression of selected marker genes (IL-8, IL-1?, CES1, NQO1, GCLM, PIR and TRIM16) was studied by real time PCR. Benzylpenicillin and phenoxymethylpenicillin were recognized as sensitizing compounds because they are capable to induce the mRNA expression of these genes in moDCs and, except for IL-8, in THP-1 cells but not in MUTZ-LC. Ampicillin stimulated the expression of some marker genes in moDCs and THP-1 cells. SMX did not affect the expression of these genes in THP-1, however, in moDCs, at least PIR was enhanced and there was an increase of the release of IL-8. These data reveal that novel in vitro DC based assays might play a role in the evaluation of the allergenic potential of novel drug compounds, but these systems seem to lack the ability to detect the sensitizing potential of prohaptens that require metabolic activation prior to sensitization and moDCs seem to be superior with regard to the sensitivity compared with THP-1 and MUTZ-3 cell lines. -- Highlights: ? We tested the sensitizing potential of small molecular weight drugs in vitro. ? In vitro assays were performed with moDCs and THP-1 cells. ? Beta-lactam antibiotics can be recognized as sensitizing compounds. ? They affect the expression of metabolic enzymes, cytokines and transcription factors. ? Sulfamethoxazole has no measurable effect on THP-1 cells and moDCs.

  3. A New WIMP Population in the Solar System and New Signals for Dark-Matter Detectors

    E-print Network

    Thibault Damour; Lawrence M. Krauss

    1998-12-29

    We describe in detail how perturbations due to the planets can cause a sub-population of WIMPs captured by scattering in surface layers of the Sun to evolve to have orbits which no longer intersect the Sun. We argue that such WIMPs, if their orbit has a semi-major axis less than 1/2 of Jupiter's, can persist in the solar system for cosmological timescales. This leads to a new, previously unanticipated WIMP population intersecting the Earth's orbit. The WIMP-nucleon cross sections required for this population to be significant are precisely those in the range predicted for SUSY dark matter, lying near the present limits obtained by direct underground dark matter searches using cyrogenic detectors. Thus, if a WIMP signal is observed in the next generation of detectors, a potentially measurable signal due to this new population must exist. This signal, lying in the keV range for Germanium detectors, would be complementary to that of galactic halo WIMPs. A comparison of event rates, anisotropies, and annual modulations would not only yield additional confirmation that any claimed signal is indeed WIMP-based, but would also allow one to gain information on the nature of the underlying dark matter model.

  4. Determining ratios of WIMP-nucleon cross sections from direct dark matter detection data

    SciTech Connect

    Shan, Chung-Lin

    2011-07-01

    Weakly Interacting Massive Particles (WIMPs) are one of the leading candidates for Dark Matter. So far the usual procedure for constraining the WIMP-nucleon cross sections in direct Dark Matter detection experiments have been to fit the predicted event rate based on some model(s) of the Galactic halo and of WIMPs to experimental data. One has to assume whether the spin-independent (SI) or the spin-dependent (SD) WIMP-nucleus interaction dominates, and results of such data analyses are also expressed as functions of the as yet unknown WIMP mass. In this article, I introduce methods for extracting information on the WIMP-nucleon cross sections by considering a general combination of the SI and SD interactions. Neither prior knowledge about the local density and the velocity distribution of halo WIMPs nor about their mass is needed. Assuming that an exponential-like shape of the recoil spectrum is confirmed from experimental data, the required information are only the measured recoil energies (in low energy ranges) and the number of events in the first energy bin from two or more experiments.

  5. Generalized spin-dependent WIMP-nucleus interactions and the DAMA modulation effect

    NASA Astrophysics Data System (ADS)

    Scopel, Stefano; Yoon, Kook-Hyun; Yoon, Jong-Hyun

    2015-07-01

    Guided by non-relativistic Effective Field Theory (EFT) we classify the most general spin-dependent interactions between a fermionic Weakly Interacting Massive Particle (WIMP) and nuclei, and within this class of models we discuss the viability of an interpretation of the DAMA modulation result in terms of a signal from WIMP elastic scatterings using a halo-independent approach. We find that, although several relativistic EFT's can lead to a spin-dependent cross section, in some cases with an explicit, non-negligible dependence on the WIMP incoming velocity, three main scenarios can be singled out in the non-relativistic limit which approximately encompass them all, and that only differ by their dependence on the transferred momentum. For two of them compatibility between DAMA and other constraints is possible for a WIMP mass below 30 GeV, but only for a WIMP velocity distribution in the halo of our Galaxy which departs from a Maxwellian. This is achieved by combining a suppression of the WIMP effective coupling to neutrons (to evade constraints from xenon and germanium detectors) to an explicit quadratic or quartic dependence of the cross section on the transferred momentum (that leads to a relative enhancement of the expected rate off sodium in DAMA compared to that off fluorine in droplet detectors and bubble chambers). For larger WIMP masses the same scenarios are excluded by scatterings off iodine in COUPP.

  6. Estrogen Receptor ? Isoform 5 Confers Sensitivity of Breast Cancer Cell Lines to Chemotherapeutic Agent-Induced Apoptosis through Interaction with Bcl2L1212

    PubMed Central

    Lee, Ming-Tsung; Ho, Shuk-Mei; Tarapore, Pheruza; Chung, Irving; Leung, Yuet-Kin

    2013-01-01

    Alternative splicing of estrogen receptor ? (ER?) yields five isoforms, but their functions remain elusive. ER? isoform 5 (ER?5) has been positively correlated with better prognosis and longer survival of patients with breast cancer (BCa) in various clinical studies. In this study, we investigated the inhibitory role of ER?5 in BCa cells. Although ER?5 does not reduce proliferation of BCa cell lines MCF-7 and MDA-MB-231, its ectopic expression significantly decreases their survival by sensitizing them to doxorubicin- or cisplatin-induced apoptosis through the intrinsic apoptotic pathway. Moreover, we discovered Bcl2L12, which belongs to the Bcl-2 family regulating apoptosis, to be a specific interacting partner of ER?5, but not ER?1 or ER?, in an estradiol-independent manner. Knockdown of Bcl2L12 enhanced doxorubicin- or cisplatin-induced apoptosis, and this process was further promoted by ectopic expression of ER?5. Whereas Bcl2L12 was previously shown to inhibit apoptosis through binding to caspase 7, such interaction is reduced in the presence of ER?5, suggesting a mechanism by which ER?5 sensitizes cells to apoptosis. In conclusion, ER?5 interacts with Bcl2L12 and functions in a novel estrogen-independent molecular pathway that promotes chemotherapeutic Agent-Induced in vitro apoptosis of BCa cell lines. PMID:24339738

  7. Limits on spin-dependent WIMP-nucleon interactions from the Cryogenic Dark Matter Search

    E-print Network

    CDMS Collaboration

    2006-01-17

    The Cryogenic Dark Matter Search (CDMS) is an experiment to detect weakly interacting massive particles (WIMPs) based on their interactions with Ge and Si nuclei. We report the results of an analysis of data from the first two runs of CDMS at the Soudan Underground Laboratory in terms of spin-dependent WIMP-nucleon interactions on 73Ge and 29Si. These data exclude new regions of spin-dependent WIMP-nucleon interaction parameter space, including regions relevant to spin-dependent interpretations of the annual modulation signal reported by the DAMA/NaI experiment.

  8. Ultra-cold WIMPs: relics of non-standard pre-BBN cosmologies

    E-print Network

    Graciela B. Gelmini; Paolo Gondolo

    2008-08-20

    Weakly interacting massive particles (WIMPs) are one of very few probes of cosmology before Big Bang nucleosynthesis (BBN). We point out that in scenarios in which the Universe evolves in a non-standard manner during and after WIMP kinetic decoupling, the horizon mass scale at decoupling can be smaller and the dark matter WIMPs can be colder than in standard cosmology. This would lead to much smaller first objects in hierarchical structure formation. In low reheating temperature scenarios the effect may be large enough as to noticeably enhance indirect detection signals in GLAST and other detectors, by up to two orders of magnitude.

  9. Limits on dark matter WIMPs using upward-going muons in the MACRO detector

    E-print Network

    The MACRO Collaboration; M. Ambrosio et al

    1998-12-16

    We perform an indirect search for Weakly Interacting Massive Particles (WIMPs) using the MACRO detector to look for neutrino-induced upward-going muons resulting from the annihilation of WIMPs trapped in the Sun and Earth. The search is conducted in various angular cones centered on the Sun and Earth to accommodate a range of WIMP masses. No significant excess over the background from atmospheric neutrinos is seen and limits are placed on the upward-going muon fluxes from Sun and Earth. These limits are used to constrain neutralino particle parameters from supersymmetric theory, including those suggested by recent results from DAMA/NaI.

  10. Gravitationally Induced Particle Production and its Impact on the WIMP Abundance

    E-print Network

    I. Baranov; J. A. S. Lima

    2015-10-21

    A large set of independent astronomical observations have provided a strong evidence for nonbaryonic dark matter in the Universe. One of the most investigated candidates is an unknown long-lived Weakly Interacting Massive Particle (WIMP) which was in thermal equilibrium with the primeval plasma. Here we investigate the WIMP abundance based on the relativistic kinetic treatment for gravitationally induced particle production recently proposed in the literature (Lima \\& Baranov, Phys. Rev. D {\\bf 90}, 043515, 2014). The new evolution equation is deduced and solved both numerically and also through a semi-analytical approach. The predictions of the WIMP observables are discussed and compared with the ones obtained in the standard approach.

  11. Gravitationally induced particle production and its impact on the WIMP abundance

    NASA Astrophysics Data System (ADS)

    Baranov, I.; Lima, J. A. S.

    2015-12-01

    A large set of independent astronomical observations have provided a strong evidence for nonbaryonic dark matter in the Universe. One of the most investigated candidates is an unknown long-lived Weakly Interacting Massive Particle (WIMP) which was in thermal equilibrium with the primeval plasma. Here we investigate the WIMP abundance based on the relativistic kinetic treatment for gravitationally induced particle production recently proposed in the literature (Lima and Baranov, 2014) [16]. The new evolution equation is deduced and solved both numerically and through a semi-analytical approach. The predictions of the WIMP observables are discussed and compared with the ones obtained in the standard approach.

  12. Response to mTOR inhibition: activity of eIF4E predicts sensitivity in cell lines and acquired changes in eIF4E regulation in breast cancer

    E-print Network

    Satheesha, Sampoorna; Cookson, Victoria J.; Coleman, Louise J.; Ingram, Nicola; Madhok, Brijesh; Hanby, Andrew M.; Suleman, Charlotte A. B.; Sabine, Vicky S.; Macaskill, E. Jane; Bartlett, John M. S.; Dixon, J. Michael; McElwaine, Jim N.; Hughes, Thomas A.

    2011-02-14

    . Surprisingly, non-transformed cell lines were not less sensitive to rapamycin and did not have lower eIF4E activities than cancer lines, suggesting the mTOR/4E-BP1/eIF4E axis is deregulated in these non-transformed cells. In the context of clinical breast...

  13. PAMELA, DAMA, INTEGRAL and Signatures of Metastable Excited WIMPs

    E-print Network

    Douglas P. Finkbeiner; Tracy Slatyer; Neal Weiner; Itay Yavin

    2009-06-25

    Models of dark matter with ~ GeV scale force mediators provide attractive explanations of many high energy anomalies, including PAMELA, ATIC, and the WMAP haze. At the same time, by exploiting the ~ MeV scale excited states that are automatically present in such theories, these models naturally explain the DAMA/LIBRA and INTEGRAL signals through the inelastic dark matter (iDM) and exciting dark matter (XDM) scenarios, respectively. Interestingly, with only weak kinetic mixing to hypercharge to mediate decays, the lifetime of excited states with delta lived states are intriguing. We find that CDMS constrains the fractional relic population of ~100 keV states to be <~ 10^-2, for a 1 TeV WIMP with sigma_n = 10^-40 cm^2. Upcoming searches at CDMS, as well as xenon, silicon, and argon targets, can push this limit significantly lower. We also consider the possibility that the DAMA excitation occurs from a metastable state into the XDM state, which decays via e+e- emission, which allows lighter states to explain the INTEGRAL signal due to the small kinetic energies required. Such models yield dramatic signals from down-scattering, with spectra peaking at high energies, sometimes as high as ~1 MeV, well outside the usual search windows. Such signals would be visible at future Ar and Si experiments, and may be visible at Ge and Xe experiments. We also consider other XDM models involving ~ 500 keV metastable states, and find they can allow lighter WIMPs to explain INTEGRAL as well.

  14. The NAIAD experiment for WIMP searches at Boulby mine and recent results

    E-print Network

    B. Ahmed; G. J. Alner; H. Araujo; J. C. Barton; A. Bewick; M. J. Carson; D. Davidge; J. V. Dawson; T. Gamble; S. P. Hart; R. Hollingworth; A. S. Howard; W. G. Jones; M. K. Joshi; V. A. Kudryavtsev; T. B. Lawson; V. Lebedenko; M. J. Lehner; J. D. Lewin; P. K. Lightfoot; I. Liubarsky; R. Luscher; J. E. McMillan; B. Morgan; G. Nicklin; S. M. Paling; R. M. Preece; J. J. Quenby; J. W. Roberts; M. Robinson; N. J. T. Smith; P. F. Smith; N. J. C. Spooner; T. J. Sumner; D. R. Tovey

    2003-01-31

    The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulated NaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6 kg x year exposure) have been used to set upper limits on the WIMP-nucleon spin-independent and WIMP-proton spin-dependent cross-sections. Pulse shape analysis has been applied to discriminate between nuclear recoils, as may be caused by WIMP interactions, and electron recoils due to gamma background. Various calibrations of crystals are presented.

  15. The NAIAD experiment for WIMP searches at Boulby mine and recent results

    E-print Network

    Ahmed, B; Araújo, H M; Barton, J C; Bewick, A; Carson, M J; Davidge, D; Dawson, J V; Gamble, T; Hart, S P; Hollingworth, R J; Howard, A S; Jones, W G; Joshi, M K; Kudryavtsev, V A; Lawson, T B; Lebedenko, V; Lehner, M J; Lewin, J D; Lightfoot, P K; Liubarsky, I; Lüscher, R; McMillan, J E; Morgan, B; Nicklin, G; Paling, S M; Preece, R M; Quenby, J J; Roberts, J W; Robinson, M; Smith, N J T; Smith, P F; Spooner, N J C; Sumner, T J; Tovey, Daniel R

    2003-01-01

    The NAIAD experiment (NaI Advanced Detector) for WIMP dark matter searches at Boulby mine (UK) is described. The detector consists of an array of encapsulated and unencapsulated NaI(Tl) crystals with high light yield. Six crystals are collecting data at present. Data accumulated by four of them (10.6 kg x year exposure) have been used to set upper limits on the WIMP-nucleon spin-independent and WIMP-proton spin-dependent cross-sections. Pulse shape analysis has been applied to discriminate between nuclear recoils, as may be caused by WIMP interactions, and electron recoils due to gamma background. Various calibrations of crystals are presented.

  16. TPB Evaporation and Slow Control of WIMP detector, Dark Side-10

    E-print Network

    Petta, Jason

    dwarfs. WIMPs are exotic particles from Big Bang such as neutralinos. Today, as assumed by the Standard model and super-symmetry theory, dark matter is believed to consist of Weakly Interacting Massive

  17. Search for Dark Matter WIMPs using Upward Through-going Muons in Super-Kamiokande

    E-print Network

    Super-Kamiokande Collaboration; :; S. Desai; Y. Ashie; S. Fukuda; Y. Fukuda; K. Ishihara; Y. Itow; Y. Koshio; A. Minamino; M. Miura; S. Moriyama; M. Nakahata; T. Namba; R. Nambu; Y. Obayashi; N. Sakurai; M. Shiozawa; Y. Suzuki; H. Takeuchi; Y. Takeuchi; S. Yamada; M. Ishitsuka; T. Kajita; K. Kaneyuki; S. Nakayama; A. Okada; T. Ooyabu; C. Saji; M. Earl; E. Kearns; J. L. Stone; L. R. Sulak; C. W. Walter; W. Wang; M. Goldhaber; T. Barszczak; D. Casper; J. P. Cravens; W. Gajewski; W. R. Kropp; S. Mine; D. W. Liu; M. B. Smy; H. W. Sobel; C. W. Sterner; M. R. Vagins; K. S. Ganezer; J. Hill; W. E. Keig; J. Y. Kim; I. T. Lim; R. W. Ellsworth; S. Tasaka; G. Guillian; A. Kibayashi; J. G. Learned; S. Matsuno; D. Takemori; M. D. Messier; Y. Hayato; A. K. Ichikawa; T. Ishida; T. Ishii; T. Iwashita; J. Kameda; T. Kobayashi; T. Maruyama; K. Nakamura; K. Nitta; Y. Oyama; M. Sakuda; Y. Totsuka; A. T. Suzuki; M. Hasegawa; K. Hayashi; T. Inagaki; I. Kato; H. Maesaka; T. Morita; T. Nakaya; K. Nishikawa; T. Sasaki; S. Ueda; S. Yamamoto; T. J. Haines; S. Dazeley; S. Hatakeyama; R. Svoboda; E. Blaufuss; J. A. Goodman; G. W. Sullivan; D. Turcan; K. Scholberg; A. Habig; C. K. Jung; T. Kato; K. Kobayashi; M. Malek; C. Mauger; C. McGrew; A. Sarrat; E. Sharkey; C. Yanagisawa; T. Toshito; C. Mitsuda; K. Miyano; T. Shibata; Y. Kajiyama; Y. Nagashima; M. Takita; M. Yoshida; H. I. Kim; H. Okazawa; T. Ishizuka; Y. Choi; H. K. Seo; Y. Gando; T. Hasegawa; K. Inoue; J. Shirai; A. Suzuki; M. Koshiba; T. Hashimoto; Y. Nakajima; K. Nishijima; T. Harada; H. Ishino; M. Morii; R. Nishimura; Y. Watanabe; D. Kielczewska; J. Zalipska; R. Gran; K. K. Shiraishi; K. Washburn; R. J. Wilkes

    2004-07-27

    We present the results of indirect searches for Weakly Interacting Massive Particles (WIMPs) with 1679.6 live days of data from the Super-Kamiokande detector using neutrino-induced upward through-going muons. The search is performed by looking for an excess of high energy muon neutrinos from WIMP annihilations in the Sun, the core of the Earth, and the Galactic Center, as compared to the number expected from the atmospheric neutrino background. No statistically significant excess was seen. We calculate flux limits in various angular cones around each of the above celestial objects. We obtain conservative model-independent upper limits on WIMP-nucleon cross-section as a function of WIMP mass and compare these results with the corresponding results from direct dark matter detection experiments.

  18. Search for Dark Matter WIMPs using Upward Through-going Muons in Super-Kamiokande

    E-print Network

    Desai, S; Fukuda, S; Fukuda, Y; Ishihara, K; Itow, Y; Koshio, Y; Minamino, A; Miura, M; Moriyama, S; Nakahata, M; Namba, T; Nambu, R; Obayashi, Y; Sakurai, N; Shiozawa, M; Suzuki, Y; Takeuchi, H; Takeuchi, Y; Yamada, S; Ishitsuka, M; Kajita, T; Kaneyuki, K; Nakayama, S; Okada, A; Ooyabu, T; Saji, C; Earl, M; Kearns, E; Stone, J L; Sulak, L R; Walter, C W; Wang, W; Goldhaber, M; Barszczak, T; Casper, D; Cravens, J P; Gajewski, W; Kropp, W R; Mine, S; Liu, D W; Smy, M B; Sobel, H W; Sterner, C W; Vagins, M R; Ganezer, K S; Hill, J; Keig, W E; Kim, J Y; Lim, I T; Ellsworth, R W; Tasaka, S; Guillian, G; Kibayashi, A; Learned, J G; Matsuno, S; Takemori, D; Messier, M D; Hayato, Y; Ichikawa, A K; Ishida, T; Ishii, T; Iwashita, T; Kameda, J; Kobayashi, T; Maruyama, T; Nakamura, K; Nitta, K; Oyama, Y; Sakuda, M; Totsuka, Y; Suzuki, A T; Hasegawa, M; Hayashi, K; Inagaki, T; Kato, I; Maesaka, H; Morita, T; Nakaya, T; Nishikawa, K; Sasaki, T; Ueda, S; Yamamoto, S; Haines, T J; Dazeley, S; Hatakeyama, S; Svoboda, R; Blaufuss, E; Goodman, J A; Sullivan, G W; Turcan, D; Scholberg, K; Habig, A; Jung, C K; Kato, T; Kobayashi, K; Malek, M; Mauger, C; McGrew, C; Sarrat, A; Sharkey, E; Yanagisawa, C; Toshito, T; Mitsuda, C; Miyano, K; Shibata, T; Kajiyama, Y; Nagashima, Y; Takita, M; Yoshida, M; Kim, H I; Kim, S B; Yoo, J; Okazawa, H; Ishizuka, T; Choi, Y; Seo, H K; Gando, Y; Hasegawa, T; Inoue, K; Shirai, J; Suzuki, A; Koshiba, M; Hashimoto, T; Nakajima, Y; Nishijima, K; Harada, T; Ishino, H; Morii, M; Nishimura, R; Watanabe, Y; Kielczewska, D; Zalipska, J; Gran, R; Shiraishi, K K; Washburn, K; Wilkes, R J

    2004-01-01

    We present the results of indirect searches for Weakly Interacting Massive Particles (WIMPs) with 1679.6 live days of data from the Super-Kamiokande detector using neutrino-induced upward through-going muons. The search is performed by looking for an excess of high energy muon neutrinos from WIMP annihilations in the Sun, the core of the Earth, and the Galactic Center, as compared to the number expected from the atmospheric neutrino background. No statistically significant excess was seen. We calculate flux limits in various angular cones around each of the above celestial objects. We obtain conservative model-independent upper limits on WIMP-nucleon cross-section as a function of WIMP mass and compare these results with the corresponding results from direct dark matter detection experiments.

  19. A new population of WIMPs in the solar system and indirect detection rates

    E-print Network

    Lars Bergstrom; Thibault Damour; Joakim Edsjo; Lawrence M. Krauss; Piero Ullio

    2000-12-11

    A new Solar System population of Weakly Interacting Massive Particle (WIMP) dark matter has been proposed to exist. We investigate the implications of this population on indirect signals in neutrino telescopes (due to WIMP annihilations in the Earth) for the case when the WIMP is the lightest neutralino of the MSSM, the minimal supersymmetric extension of the standard model. The velocity distribution and capture rate of this new population is evaluated and the flux of neutrino-induced muons from the center of the Earth in neutrino telescopes is calculated. We show that the effects of the new population can be crucial for masses around 60-120 GeV, where enhancements of the predicted muon flux from the center of the Earth by up to a factor of 100 compared to previously published estimates occur. As a result of the new WIMP population, neutrino telescopes should be able to probe a much larger region of parameter space in this mass range.

  20. Model independent WIMP Searches in full Simulation of the ILD Detector

    E-print Network

    Christoph Bartels; Jenny List

    2010-07-16

    In this study the ILC's capabilities for detecting WIMPs and measure their properties are investigated. The signal events are detected by associated production of Initial State Radiation (ISR). A model independent formulation of the signal cross section is used. The cross section is normalized by inference from the observed abundance of cosmological Dark Matter (DM). The study is performed in full simulation of the ILD00 detector model. The prospects of determining the WIMP parameters individually and simultaneously are presented.

  1. Automated and sensitive analysis of 28-epihomobrassinolide in Arabidopsis thaliana by on-line polymer monolith microextraction coupled to liquid chromatography-mass spectrometry.

    PubMed

    Wang, Xin; Ma, Qiao; Li, Min; Chang, Cuilan; Bai, Yu; Feng, Yuqi; Liu, Huwei

    2013-11-22

    By on-line solid phase microextraction with polymer monolith coupled to liquid chromatography-mass spectrometry (SPME-LC-MS), an automated and sensitive method for analysis of the endogenous 28-epihomobrassinolide (28-epihomoBR) in Arabidopsis thaliana was developed in this work. Firstly, a poly(methacrylic acid-co-ethylene dimethacrylate) (poly(MAA-co-EDMA)) monolith was prepared in the capillary and applied in in-tube SPME. Polyethylene glycol (PEG) was used as porogen to adjust the specific surface area and hydrophobicity of the target monolith to get satisfactory permeability, high mechanical strength and good stability. The optimized monolith was then served as extraction medium for analysis of the derivatized 28-epihomoBR in plant samples with the cleanup of matrix and enrichment of desired analyte at the same time. Good linearity was obtained in the linear range of 5-500 ng/L with the coefficient of determination (R(2)) of 0.9996. The limit of detection (S/N=3) of 28-epihomoBR was found to be 2.0 ng/L and the limit of quantification (S/N=10) was 5.0 ng/L. Using this method, the endogenous 0.101 ng/g (FW) 28-epihomoBR was successfully detected from only 400mg A. thaliana samples with satisfactory recovery (80.3-92.1%) and reproducibility (RSD 6.8-9.6%). Comparing with other sample pretreatment methods, this automated on-line SPME-LC-MS method is rapid, sensitive, reproducible and laborsaving. PMID:23915641

  2. A retinal pigment epithelium-derived cell line from transgenic mouse harboring temperature-sensitive simian virus 40 large T-antigen gene.

    PubMed

    Kato, K; Ishiguro, S; Yamamoto, H; Yanai, N; Obinata, M; Tamai, M

    1996-12-01

    We established a retinal pigment epithelium-derived cell line from transgenic mouse harboring temperature-sensitive simian virus 40 T-antigen gene (tsSV40T) and examined its characteristics. We enucleated both eyes from a 2-month-old transgenic mouse and removed the retinal pigment epithelial (RPE) cells and neuroretinal cells. After cloning the RPE cells, we obtained a cell line (RPET). RPET cells grew well at 33 degrees C but not at 37 degrees C, expressing on the temperature-sensitive character of tsSV40T, and maintained characters of RPE cells such as T1-tyrosinase production, phagocytosis of rod outer segments, and presence of cytokeratin, microvilli on the cell surface and lysosome-like granules around the Golgi apparatus in the cytoplasm. Conditioned medium (CM) from a culture of neuroretinal cells harboring tsSV40T was essentially required for growth. The factor(s) in CM was heat-and acid labile, but was resistant to trypsin digestion. In the presence of 3% CM, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) and strong effects on RPET cells, whereas insulin, insulin-like growth factor I (IGF-I), and IGF-II had moderate growth effects. Interestingly, none of these growth factors stimulated the RPET cells in the absence of CM. EHS-Matrix had growth effect, whereas laminin, collagen types I and IV, and fibronectin had no marked growth effects on RPET cells. RPET cells were morphologically changed on a laminin-coated dish. They could not spread on the coated dish, and the majority of the cells floated. But when the floating cells were transferred to non-coated dishes, they immediately attached themselves. These results suggest that RPET cells are a good model for for finding novel growth factor(s) and for investigating the mechanism of cell-laminin attachment. PMID:9078403

  3. COUPP - a search for dark matter with a continuously sensitive bubble chamber

    SciTech Connect

    Collar, Juan,; Crum, Keith; Mishra, Smriti; Nakazawa, Dante; Odom, Brian; Rasmussen, Julia; Riley, Nathan; Szydagis, Matthew; Behnke, Ed; Levine, Ilan; Vander Werf, Nate; Cooper, Peter; Crisler, Mike; Hu, Martin; Ramberg, Erik; Sonnenschein, Andrew; Tschirhart, Robert; /Fermilab

    2007-01-01

    We propose to construct and operate a 60-kg room temperature CF{sub 3}I bubble chamber as a prototype dark matter (WIMP) detector. Operating in weakly-superheated mode, the chamber will be sensitive to WIMP induced nuclear recoils above 10 keV, while rejecting background electron recoils at a level approaching 10{sup 10}. We would first commission and operate this chamber in the MINOS near detector hall with the goal to demonstrate stable operation and measure internal contamination and any other backgrounds. This chamber, or an improved version, would then be relocated to an appropriate deep underground site such as the Soudan Mine. This detector will have unique sensitivity to spin-dependent WIMP-nucleon couplings, and even in this early stage of development will attain competitive sensitivity to spin-independent couplings.

  4. Peroxyacetyl nitrate-induced oxidative and calcium signaling events leading to cell death in ozone-sensitive tobacco cell-line

    PubMed Central

    Yukihiro, Masaru; Hiramatsu, Takuya; Bouteau, Francois; Kadono, Takashi; Kawano, Tomonori

    2012-01-01

    It has long been concerned that some secondary air pollutants such as smog components, ozone (O3) and peroxyacetyl nitrate (PAN), are highly phytotoxic even at low concentrations. Compared with the biology of O3, we largely lack the information on the toxicity model for PAN at the cellular signaling levels. Here, we studied the cell-damaging impact of PAN using suspension culture of smog-sensitive tobacco variety (Bel-W3). The cells were exposed to freshly synthesized PAN and the induced cell death was assessed under microscope after staining with Evans blue. Involvement of reactive oxygen species (ROS) in PAN toxicity was suggested by PAN-dependently increased intracellular H2O2 and also by the cell-protective effects of ROS scavengers and related inhibitors. Calcium chelator also lowered the level of PAN-induced cell death, indicating that Ca2+ is also involved. Using a transgenic cell line expressing aequorin, an increase in cytosolic Ca2+ concentration responsive to the pulse of PAN, but sensitive to Ca2+ channel blockers, was recorded, indicating that Ca2+ channels are activated by PAN or PAN-derived signals. Above data show some similarity between the signaling mechanisms responsive to O3 and PAN. PMID:22301977

  5. Quantitative evaluation of cellular uptake, DNA incorporation and adduct formation in cisplatin sensitive and resistant cell lines: Comparison of different Pt-containing drugs.

    PubMed

    Corte-Rodríguez, M; Espina, M; Sierra, L M; Blanco, E; Ames, T; Montes-Bayón, M; Sanz-Medel, A

    2015-11-01

    The use of Pt-containing compounds as chemotherapeutic agents facilitates drug monitoring by using highly sensitive elemental techniques like inductively coupled plasma mass spectrometry (ICP-MS). However, methodological problems arise when trying to compare different experiments due to the high variability of biological parameters. In this work we have attempted to identify and correct such variations in order to compare the biological behavior of cisplatin, oxaliplatin and pyrodach-2 (a novel platinum-containing agent). A detailed study to address differential cellular uptake has been conducted in three different cell lines: lung adenocarcinoma (A549); cisplatin-sensitive ovarian carcinoma (A2780); and cisplatin-resistant ovarian carcinoma (A2780cis). The normalization of Pt results to cell mass, after freeze-drying, has been used to minimize the errors associated with cell counting. Similarly, Pt accumulation in DNA has been evaluated by referencing the Pt results to the DNA concentration, as measured by (31)P monitoring using flow-injection and ICP-MS detection. These strategies have permitted to address significantly lower Pt levels in the resistant cells when treated with cisplatin or oxaliplatin as well as an independent behaviour from the cell type (sensitive or resistant) for pyrodach-2. Similarly, different levels of incorporation in DNA have been found for the three drugs depending on the cell model revealing a different behavior regarding cell cisplatin resistance. Further speciation experiments (by using complementary HPLC-ICP-MS and HPLC-ESI-Q-TOF MS) have shown that the main target in DNA is still the N7 of the guanine but with different kinetics of the ligand exchange mechanism for each of the compounds under evaluation. PMID:26352094

  6. Differentiation-associated toxin receptor modulation, cytokine production, and sensitivity to Shiga-like toxins in human monocytes and monocytic cell lines.

    PubMed Central

    Ramegowda, B; Tesh, V L

    1996-01-01

    Infections with Shiga toxin-producing Shigella dysenteriae type 1 or Shiga-like toxin (SLT)-producing Escherichia coli cause bloody diarrhea and are associated with an increased risk of acute renal failure and severe neurological complications. Histopathological examination of human and animal tissues suggests that the target cells for toxin action are vascular endothelial cells. Proinflammatory cytokines regulate endothelial cell membrane expression of the glycolipid globotriaosylceramide (Gb(3)) which serves as the toxin receptor, suggesting that the host response to the toxins or other bacterial products may contribute to pathogenesis by regulating target cell sensitivity to the toxins. We examined the effects of purified SLTs on human peripheral blood monocytes (PBMn) and two monocytic cell lines. Undifferentiated THP-1 cells were sensitive to SLTs. Treatment of the cells with a number of differentiation factors resulted in increased toxin resistance which was associated with decreased toxin receptor expression. U-937 cells, irrespective of maturation state, and PBMn were resistant to the toxins. U-937 cells expressed low levels of GB(3), and toxin receptor expression was not altered during differentiation. Treatment of monocytic cells with tumor necrosis factor alpha (TNF-alpha) did not markedly increase sensitivity or alter toxin receptor expression. Undifferentiated monocytic cells failed to synthesize TNF and interleukin 1beta when treated with sublethal concentrations of SLT type I (SLT-I), whereas cells treated with 12-0-tetradecanoylphorbol-13-acetate acquired the ability to produce cytokines when stimulated with SLT-I. When stimulated with SLT-I, U-937 cells produced lower levels of TNF than PBMn and THP-1 cells did. PMID:8606075

  7. An indirect search for WIMPs in the Sun and the Earth using upward-going muon events in

    E-print Network

    Tokyo, University of

    An indirect search for WIMPs in the Sun and the Earth using upward-going muon events in Super;Abstract We present the result of an indirect search for high energy neutrinos from WIMP annihilation of upward-going muon flux induced by WIMPs of 100 GeV/c2 which annihilate in the Sun were 2.1 ×103 km-2 y-1

  8. Gamma-ray lines and one-loop continuum from s-channel dark matter annihilations

    SciTech Connect

    Jackson, C.B.; Servant, Géraldine; Shaughnessy, Gabe; Tait, Tim M.P.; Taoso, Marco E-mail: chris@uta.edu E-mail: ttait@uci.edu

    2013-07-01

    The era of indirect detection searches for dark matter has begun, with the sensitivities of gamma-ray detectors now approaching the parameter space relevant for weakly interacting massive particles. In particular, gamma ray lines would be smoking gun signatures of dark matter annihilation, although they are typically suppressed compared to the continuum. In this paper, we pay particular attention to the 1-loop continuum generated together with the gamma-ray lines and investigate under which conditions a dark matter model can naturally lead to a line signal that is relatively enhanced. We study generic classes of models in which DM is a fermion that annihilates through an s-channel mediator which is either a vector or scalar and identify the coupling and mass conditions under which large line signals occur. We focus on the ''forbidden channel mechanism'' advocated a few years ago in the ''Higgs in space'' scenario for which tree level annihilation is kinematically forbidden today. Detailed calculations of all 1-loop annihilation channels are provided. We single out very simple models with a large line over continuum ratio and present general predictions for a large range of WIMP masses that are relevant not only for Fermi and Hess II but also for the next generation of telescopes such as CTA and Gamma-400. Constraints from the relic abundance, direct detection and collider bounds are also discussed.

  9. Neutrino signals from electroweak bremsstrahlung in solar WIMP annihilation

    SciTech Connect

    Bell, Nicole F.; Brennan, Amelia J.; Jacques, Thomas D. E-mail: a.brennan@pgrad.unimelb.edu.au

    2012-10-01

    Bremsstrahlung of W and Z gauge bosons, or photons, can be an important dark matter annihilation channel. In many popular models in which the annihilation to a pair of light fermions is helicity suppressed, these bremsstrahlung processes can lift the suppression and thus become the dominant annihilation channels. The resulting dark matter annihilation products contain a large, energetic, neutrino component. We consider solar WIMP annihilation in the case where electroweak bremsstrahlung dominates, and calculate the resulting neutrino spectra. The flux consists of primary neutrinos produced in processes such as ????-bar ?Z and ????-bar lW, and secondary neutrinos produced via the decays of gauge bosons and charged leptons. After dealing with the neutrino propagation and flavour evolution in the Sun, we consider the prospects for detection in neutrino experiments on Earth. We compare our signal with that for annihilation to W{sup +}W{sup ?}, and show that, for a given annihilation rate, the bremsstrahlung annihilation channel produces a larger signal by a factor of a few.

  10. An Interface for Sensitive Analysis of Monoamine Neurotransmitters by Ion-Pair Chromatography–ESI-MS with Continuous On-Line Elimination of Ion-Pair Reagents

    PubMed Central

    Shi, Shuyun; Zhao, Binqing; Yagnik, Gargey; Zhou, Feimeng

    2013-01-01

    A challenge in coupling ion-pair chromatography (IPC) on-line with electrospray ionization-mass spectrometry (ESI-MS) is that the nonvolatile ion-pair reagent (e.g., alkyl sulfate for amines or tetrabutylammonium for carboxylic acids) in the mobile phase suppresses the ESI-MS signals in the gas phase and their accumulation can clog the MS sampling interface. Consequently, IPC–ESI-MS is conducted either with a volatile ion-pair reagent, which could compromise the analyte separation efficiency, or with a downstream ion-exchange column to rid the ion-pair reagents of the mobile phase. In the latter approach, the limited capacity of ion-exchange columns requires frequent off-line column regeneration, which affects the separation throughput and prohibits long separations from being performed. A dual-valve, dual-ion exchange column interface of IPC–ESI-MS is designed for undisrupted separations and simultaneous column regeneration. Owing to the efficacy in removing the ion-pair reagent, the detection of eluents of monoamine neurotransmitters by an ion trap MS results in the limits of detection of 0.03 ?M for dopamine or DA and 0.01 ?M for 5-hydroxytryptamine or 5-HT. These values are lower than those obtained with ion trap MS of similar sensitivity when combined with the use of specialized chromatographic columns or sample preconcentration. Excellent reproducibility was attained with repeatedly regenerated ion-exchange columns (RSD = 4–6%) for an extended period of time (RSD < 6% for six days). DA and 5-HT in rat straital extracts were analyzed and our data demonstrate that interferences inherent in the tissues and the ion-pair reagent have been successfully eliminated. This simple interface should be readily amenable to the separation and MS analysis of other types of polar compounds in complex sample media. PMID:23767971

  11. Dark matter production in the early Universe: Beyond the thermal WIMP paradigm

    NASA Astrophysics Data System (ADS)

    Baer, Howard; Choi, Ki-Young; Kim, Jihn E.; Roszkowski, Leszek

    2015-02-01

    Increasingly stringent limits from LHC searches for new physics, coupled with lack of convincing signals of weakly interacting massive particle (WIMP) in dark matter searches, have tightly constrained many realizations of the standard paradigm of thermally produced WIMPs as cold dark matter. In this article, we review more generally both thermally and non-thermally produced dark matter (DM). One may classify DM models into two broad categories: one involving bosonic coherent motion (BCM) and the other involving WIMPs. BCM and WIMP candidates need, respectively, some approximate global symmetries and almost exact discrete symmetries. Supersymmetric axion models are highly motivated since they emerge from compelling and elegant solutions to the two fine-tuning problems of the Standard Model: the strong CP problem and the gauge hierarchy problem. We review here non-thermal relics in a general setup, but we also pay particular attention to the rich cosmological properties of various aspects of mixed SUSY/axion dark matter candidates which can involve both WIMPs and BCM in an interwoven manner. We also review briefly a panoply of alternative thermal and non-thermal DM candidates.

  12. LUX likelihood and limits on spin-independent and spin-dependent WIMP couplings with LUXCalc

    NASA Astrophysics Data System (ADS)

    Savage, Christopher; Scaffidi, Andre; White, Martin; Williams, Anthony G.

    2015-11-01

    We present LUXCalc, a new utility for calculating likelihoods and deriving weakly interacting massive particle (WIMP)-nucleon coupling limits from the recent results of the LUX direct search dark matter experiment. After a brief review of WIMP-nucleon scattering, we derive LUX limits on the spin-dependent WIMP-nucleon couplings over a broad range of WIMP masses, under standard assumptions on the relevant astrophysical parameters. We find that, under these and other common assumptions, LUX excludes the entire spin-dependent parameter space consistent with a dark matter interpretation of DAMA's anomalous signal, the first time a single experiment has been able to do so. We also revisit the case of spin-independent couplings, and demonstrate good agreement between our results and the published LUX results. Finally, we derive constraints on the parameters of an effective dark matter theory in which a spin-1 mediator interacts with a fermionic WIMP and Standard Model fermions via axial-vector couplings. A detailed appendix describes the use of LUXCalc with standard codes to place constraints on generic dark matter theories.

  13. The effects of QCD equation of state on the relic density of WIMP dark matter

    NASA Astrophysics Data System (ADS)

    Drees, Manuel; Hajkarim, Fazlollah; Rossi Schmitz, Ernany

    2015-06-01

    Weakly Interactive Massive Particles (WIMPs) are the most widely studied candidate particles forming the cold dark matter (CDM) whose existence can be inferred from a wealth of astrophysical and cosmological observations. In the framework of the minimal cosmological model detailed measurements on the cosmic microwave background by the PLANCK collaboration fix the scaled CDM relic density to ?ch2=0.1193±0.0014, with an error of less than 1.5%. In order to fully exploit this observational precision, theoretical calculations should have a comparable or smaller error. In this paper we use recent lattice QCD calculations to improve the description of the thermal plasma. This affects the predicted relic density of ``thermal WIMPs'', which once were in chemical equilibrium with Standard Model particles. For WIMP masses between 3 and 15 GeV, where QCD effects are most important, our predictions differ from earlier results by up to 9% (12%) for pure S-wave (P-wave) annihilation. We use these results to compute the thermally averaged WIMP annihilation cross section that reproduces the correct CDM relic density, for WIMP masses between 0.1 GeV and 10 TeV.

  14. The Effects of QCD Equation of State on the Relic Density of WIMP Dark Matter

    E-print Network

    Manuel Drees; Fazlollah Hajkarim; Ernany Rossi Schmitz

    2015-03-11

    Weakly Interactive Massive Particles (WIMPs) are the most widely studied candidate particles forming the cold dark matter (CDM) whose existence can be inferred from a wealth of astrophysical and cosmological observations. In the framework of the minimal cosmological model detailed measurements on the cosmic microwave background by the PLANCK collaboration fix the scaled CDM relic density to $\\Omega_{c}h^2=0.1193\\pm0.0014$, with an error of less than 1.5%. In order to fully exploit this observational precision, theoretical calculations should have a comparable or smaller error. In this paper we use recent lattice QCD calculations to improve the description of the thermal plasma. This affects the predicted relic density of "thermal WIMPs", which once were in chemical equilibrium with Standard Model particles. For WIMP masses between 3 and 15 GeV, where QCD effects are most important, our predictions differ from earlier results by up to 9% (12%) for pure S-wave (P-wave) annihilation. We use these results to compute the thermally averaged WIMP annihilation cross section that reproduces the correct CDM relic density, for WIMP masses between 0.1 GeV and 10 TeV.

  15. DNA strand breakage in normal and solar ultraviolet-sensitive ICR 2A frog cell lines exposed to solar ultraviolet wavelengths

    SciTech Connect

    Rosenstein, B.S. )

    1989-01-01

    ICR 2A frog cells and two solar ultraviolet (UV)-sensitive cell lines, DRP 36 and DRP 153, were irradiated with 150 kJ/m{sup 2} of the UV radiation produced by a fluorescent sun lamp, the radiation from which was passed through a sheet of 48A Mylar to eliminate wavelengths shorter than approximately 315 nm. The irradiated cultures were also exposed to photoreactivating light (PRL), resulting in the removal of most of the pyrimidine dimers induced by the sun lamp UV irradiation, and then incubated 0-4 hr. At the end of the incubations, the cells were subjected to the alkaline elution assay. In these elutions, the cell lysates were either treated with proteinase K (proK) to eliminate any DNA-protein crosslinks (DPC) that may be present in the cells, or left untreated with proK. For the ICR 2A cells, the level of apparent DNA single-strand breaks (ssb) detected in elutions using proK increased with the incubation time after irradiation and remained high. However, when the DNA was eluted without proK pretreatment, the number of ssb fell rapidly. In contrast, the levels of ssb decreased in the DRP 36 and DRP 153 cells regardless of the use of proK in the elutions. Hence, this differential response in ssb induction may be indicative of a system involved with recovery following irradiation with solar UV wavelengths.

  16. Development of Nano-Liposomal Formulations of Epidermal Growth Factor Receptor Inhibitors and their Pharmacological Interactions on Drug-Sensitive and Drug-Resistant Cancer Cell Lines

    NASA Astrophysics Data System (ADS)

    Trummer, Brian J.

    A rapidly expanding understanding of molecular derangements in cancer cell function has led to the development of selective, targeted chemotherapeutic agents. Growth factor signal transduction networks are frequently activated in an aberrant fashion, particularly through the activity of receptor tyrosine kinases (RTK). This has spurred an intensive effort to develop receptor tyrosine kinase inhibitors (RTKI) that are targeted to specific receptors, or receptor subfamilies. Chapter 1 reviews the pharmacology, preclinical, and clinical aspects of RTKIs that target the epidermal growth factor receptor (EGFR). EGFR inhibitors demonstrate significant success at inhibiting phosphorylation-based signaling pathways that promote cancer cell proliferation. Additionally RTKIs have physicochemical and structural characteristics that enable them to function as inhibitors of multi-drug resistance transport proteins. Thus EGFR inhibitors and other RTKIs have both on-target and off-target activities that could be beneficial in cancer therapy. However, these agents exert a number of side effects, some of which arise from their hydrophobic nature and large in vivo volume of distribution. Side effects of the EGFR inhibitor gefitinib include skin rash, severe myelotoxicity when combined with certain chemotherapeutic agents, and impairment of the blood brain barrier to xenobiotics. Weighing the preclinical and clinical observations with the EGFR inhibitors, we developed the primary overall hypothesis of this research: that drug-carrier formulations of RTKIs such as the EGFR inhibitors could be developed based on nanoparticulate liposomal carriers. Theoretically, this carrier strategy would ameliorate toxicity and improve the biodistribution and tumor selectivity of these agents. We hypothesized specifically that liposomal formulations could shift the biodistribution of EGFR inhibitors such as gefitinib away from skin, bone marrow, and the blood brain barrier, and toward solid tumors, due to leaky tumor vasculature and the resulting Enhanced Permeability and Retention (EPR) phenomenon. In Chapter 2 we report that both gefitinib and the structurally similar EGFR inhibitor erlotinib display environment-dependent fluorescence properties. Peak excitation was 345 nm, and the emission peak ranged from 365 to 476 nm, depending upon the polarity of the environment and physical state of the drug. The fluorescence was negligible in aqueous solution, but intense in organic solvents or membrane bilayers. The environment-sensitive fluorescence properties of these drugs enabled rapid evaluation of numerous parameters affecting liposomal drug incorporation and performance. Up to 4-6 mol% of gefitinib could be incorporated in the liposome bilayer, based upon hydrophobic interactions with membrane bilayers. In contrast, 40-60 mol% could be loaded into the aqueous core of pre-formed liposomes at high efficiency, using a remote loading procedure. A stable formulation consisting of distearoylphosphatidylcholine: polyethylene glycol-distereoylphosphatidylethanolamine: cholesterol (DSPC:PEGDSPE:Chol, 9:1:5 mol:mol:mol) and containing drug at 50-60 mol% gefitinib (L-GEF) showed minimal leakage in serum-containing medium over 24 h at 37°C, which should be sufficient to improve biodistribution in vivo. Chapter 3 investigated the pharmacological activity of liposome-encapsulated gefitinib, alone and in combination with several prevalent anticancer agents. Experiments with MCF7 breast cancer cell lines demonstrated that liposome encapsulated gefitinib formulation (L-GEF) had a 2-fold higher IC50 (concentration of drug resulting in half-maximal growth inhibition) than free gefitinib. Lower in vitro potency would be consistent with delayed drug release from the carrier. Therapeutic effects were investigated in combination with the cytotoxic agents paclitaxel and doxorubicin. The drug-resistant MCF7R cell line was 23-fold more resistant to paclitaxel than the parental, drug-sensitive MCF7S cell line, and MCF7R was 12-fold more resistant than MCF7S to doxorubicin. A conce

  17. Accurate calculations of the WIMP halo around the Sun and prospects for its gamma-ray detection

    SciTech Connect

    Sivertsson, Sofia; Edsjoe, Joakim

    2010-03-15

    Galactic weakly interacting massive particles (WIMPs) may scatter off solar nuclei to orbits gravitationally bound to the Sun. Once bound, the WIMPs continue to lose energy by repeated scatters in the Sun, eventually leading to complete entrapment in the solar interior. While the density of the bound population is highest at the center of the Sun, the only observable signature of WIMP annihilations inside the Sun is neutrinos. It has been previously suggested that although the density of WIMPs just outside the Sun is lower than deep inside, gamma rays from WIMP annihilation just outside the surface of the Sun, in the so-called WIMP halo around the Sun, may be more easily detected. We here revisit this problem using detailed Monte Carlo simulations and detailed composition and structure information about the Sun to estimate the size of the gamma-ray flux. Compared to earlier simpler estimates, we find that the gamma-ray flux from WIMP annihilations in the solar WIMP halo would be negligible; no current or planned detectors would be able to detect this flux.

  18. A Search for WIMP Dark Matter Using the First Five-Tower Run of the Cryogenic Dark Matter Search

    E-print Network

    California at Berkeley, University of

    A Search for WIMP Dark Matter Using the First Five-Tower Run of the Cryogenic Dark Matter Search;A Search for WIMP Dark Matter Using the First Five-Tower Run of the Cryogenic Dark Matter Search-Tower Run of the Cryogenic Dark Matter Search by Jeffrey Peter Filippini Doctor of Philosophy in Physics

  19. Limits on spin-dependent WIMP-nucleon cross-sections from the XENON10 experiment

    E-print Network

    J. Angle; E. Aprile; F. Arneodo; L. Baudis; A. Bernstein; A. Bolozdynya; P. Brusov; L. C. C. Coelho; C. E. Dahl; L. DeViveiros; A. D. Ferella; L. M. P. Fernandes; S. Fiorucci; R. J. Gaitskell; K. L. Giboni; R. Gomez; R. Hasty; L. Kastens; J. Kwong; J. A. M. Lopes; N. Madden; A. Manalaysay; A. Manzur; D. N. McKinsey; M. E. Monzani; K. Ni; U. Oberlack; J. Orboeck; G. Plante; R. Santorelli; J. M. F. dos Santos; P. Shagin; T. Shutt; P. Sorensen; S. Schulte; C. Winant; M. Yamashita; for the XENON10 Collaboration

    2008-09-10

    XENON10 is an experiment to directly detect weakly interacting massive particle (WIMPs), which may comprise the bulk of the non-baryonic dark matter in our Universe. We report new results for spin-dependent WIMP-nucleon interactions with 129-Xe and 131-Xe from 58.6 live-days of operation at the Laboratori Nazionali del Gran Sasso (LNGS). Based on the non-observation of a WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously unexplored regions in the theoretically allowed parameter space for neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range of 10 GeV -2 TeV as a dark matter candidate under standard assumptions for its density and distribution in the galactic halo.

  20. Standard Model anatomy of WIMP dark matter direct detection II: QCD analysis and hadronic matrix elements

    E-print Network

    Hill, Richard J

    2014-01-01

    Models of Weakly Interacting Massive Particles (WIMPs) specified at the electroweak scale are systematically matched to effective theories at hadronic scales where WIMP-nucleus scattering observables are evaluated. Anomalous dimensions and heavy quark threshold matching conditions are computed for the complete basis of lowest-dimension effective operators involving quarks and gluons. The resulting QCD renormalization group evolution equations are solved. The status of relevant hadronic matrix elements is reviewed and phenomenological illustrations are given, including details for the computation of the universal limit of nucleon scattering with heavy $SU(2)_W\\times U(1)_Y$ charged WIMPs. Several cases of previously underestimated hadronic uncertainties are isolated. The results connect arbitrary models specified at the electroweak scale to a basis of $n_f=3$ flavor QCD operators. The complete basis of operators and Lorentz invariance constraints through order $v^2/c^2$ in the nonrelativistic nucleon effective...

  1. Supersymmetry and dark matter post LHC8: Why we may expect both axion and WIMP detection

    SciTech Connect

    Baer, Howard

    2014-01-01

    In the post-LHC8 era, it is perceived that what is left of SUSY model parameter space is highly finetuned in the EW sector (EWFT). We discuss how conventional measures overestimate EWFT in SUSY theory. Radiatively-driven natural SUSY (RNS) models maintain the SUSY GUT paradigm with low EWFT at 10% level, but are characterized by light higgsinos ~100–300 GeV and a thermal underabundance of WIMP dark matter. Implementing the SUSY DFSZ solution to the strong CP problem explains the small ? parameter but indicates dark matter should be comprised mainly of axions with a small admixture of higgsino-like WIMPs. While RNS might escape LHC14 searches, we would expect ultimately direct detection of both WIMPs and axions. An e?e? collider with ?(s)~500–600 GeV should provide a thorough search for the predicted light higgsinos.

  2. Limits on spin-dependent WIMP-nucleon cross sections from the XENON10 experiment.

    PubMed

    Angle, J; Aprile, E; Arneodo, F; Baudis, L; Bernstein, A; Bolozdynya, A; Coelho, L C C; Dahl, C E; DeViveiros, L; Ferella, A D; Fernandes, L M P; Fiorucci, S; Gaitskell, R J; Giboni, K L; Gomez, R; Hasty, R; Kastens, L; Kwong, J; Lopes, J A M; Madden, N; Manalaysay, A; Manzur, A; McKinsey, D N; Monzani, M E; Ni, K; Oberlack, U; Orboeck, J; Plante, G; Santorelli, R; dos Santos, J M F; Shagin, P; Shutt, T; Sorensen, P; Schulte, S; Winant, C; Yamashita, M

    2008-08-29

    XENON10 is an experiment to directly detect weakly interacting massive particles (WIMPs), which may comprise the bulk of the nonbaryonic dark matter in our Universe. We report new results for spin-dependent WIMP-nucleon interactions with 129Xe and 131Xe from 58.6 live days of operation at the Laboratori Nazionali del Gran Sasso. Based on the nonobservation of a WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously unexplored regions in the theoretically allowed parameter space for neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range of approximately 10 GeV/c2-2 TeV/c2 as a dark matter candidate under standard assumptions for its density and distribution in the galactic halo. PMID:18851599

  3. The XENON10 WIMP Search Experiment at the Gran Sasso Underground Laboratory

    E-print Network

    Laura Baudis

    2007-03-08

    XENON10 is a new direct dark matter detection experiment using liquid xenon as target for weakly interacting, massive particles (WIMPs). A two-phase (liquid/gas) time projection chamber with 15 kg fiducial mass has been installed in a low-background shield at the Gran Sasso Underground Laboratory in July 2006. After initial performance tests with various calibration sources, the science data run started on August 24, 2006. The detector has been running stably since then, and a full analysis of more than 75 live days of WIMP search data is now in progress. We present first results on gamma and neutron calibration runs, as well as a preliminary analysis of a subset of the WIMP search data.

  4. Standard Model anatomy of WIMP dark matter direct detection. II. QCD analysis and hadronic matrix elements

    NASA Astrophysics Data System (ADS)

    Hill, Richard J.; Solon, Mikhail P.

    2015-02-01

    Models of weakly interacting massive particles (WIMPs) specified at the electroweak scale are systematically matched to effective theories at hadronic scales where WIMP-nucleus scattering observables are evaluated. Anomalous dimensions and heavy-quark threshold matching conditions are computed for the complete basis of lowest-dimension effective operators involving quarks and gluons. The resulting QCD renormalization group evolution equations are solved. The status of relevant hadronic matrix elements is reviewed and phenomenological illustrations are given, including details for the computation of the universal limit of nucleon scattering with heavy S U (2 )W×U (1 )Y charged WIMPs. Several cases of previously underestimated hadronic uncertainties are isolated. The results connect arbitrary models specified at the electroweak scale to a basis of nf=3 -flavor QCD operators. The complete basis of operators and Lorentz invariance constraints through order v2/c2 in the nonrelativistic nucleon effective theory are derived.

  5. Reconstructing the WIMP velocity distribution from direct dark matter detection data with a nonnegligible threshold energy

    NASA Astrophysics Data System (ADS)

    Shan, Chung-Lin

    2015-07-01

    In this paper, we investigate the modification of our expressions developed for the model-independent data analysis procedure of the reconstruction of the (time-averaged) one-dimensional velocity distribution of galactic weakly interacting massive particles (WIMPs) with a nonnegligible experimental threshold energy. Our numerical simulations show that, for a minimal reconstructable velocity of as high as {O} (200) km/s, our model-independent modification of the estimator for the normalization constant could provide precise reconstructed velocity distribution points to match the true WIMP velocity distribution with ? 10% bias.

  6. Limits on WIMP-nucleon interactions with CsI(Tl) crystal detectors

    E-print Network

    H. S. Lee; H. C. Bhang; J. H. Choi; H. Dao; I. S. Hahn; M. J. Hwang; S. W. Jung; W. G. Kang; D. W. Kim; H. J. Kim; S. C. Kim; S. K. Kim; Y. D. Kim; J. W. Kwak; Y. J. Kwon; J. Lee; J. H. Lee; J. I. Lee; M. J. Lee; S. J. Lee; J. Li; X. Li; Y. J. Li; S. S. Myung; S. Ryu; J. H. So; Q. Yue; J. J. Zhu

    2007-08-14

    The Korea Invisible Mass Search(KIMS) experiment presents new limits on WIMP-nucleon cross section using the data from an exposure of 3409 kgd taken with low background CsI(Tl) crystals at Yangyang underground laboratory. The most stringent limit on the spin dependent interaction for pure proton case is obtained. The DAMA signal region for both spin independent and spin dependent interactions for the WIMP mass higher than 20 GeV/c^2are excluded by the single experiment with crystal scintillators.

  7. Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch (7 nm space width and 21 nm line width) using electron beam lithography with chemically amplified resist processes: I. Relationship between sensitivity and chemical gradient

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro

    2015-05-01

    Electron beam (EB) lithography used for mask and mold fabrication is an indispensable technology in the lithography used for high-volume production of semiconductor devices. With the reduction in the critical dimensions of semiconductor devices, the requirement for EB lithography also becomes severe. In this study, the feasibility of single nano patterning using EB lithography with a chemically amplified resist process was investigated. The latent images of line-and-space patterns with a 7 nm quarter-pitch (7 nm space width and 21 nm line width) were calculated on the basis of sensitization and reaction mechanisms of chemically amplified EB resists. Simulations indicated that the line-and-space patterns with 7 nm quarter-pitch can be resolved with line edge roughness of 0.9-1.9 nm with a sensitivity of 270 µC cm-2 using a 3 nm electron beam.

  8. In-Line Ozonation for Sensitive Air-Monitoring of a Mustard-Gas Simulant by Atmospheric Pressure Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Okumura, Akihiko

    2015-09-01

    A highly sensitive method for real-time air-monitoring of mustard gas (bis(2-chloroethyl) sulfide, HD), which is a lethal blister agent, is proposed. Humidified air containing a HD simulant, 2-chloroethyl ethyl sulfide (2CEES), was mixed with ozone and then analyzed by using an atmospheric pressure chemical ionization ion trap tandem mass spectrometer. Mass-spectral ion peaks attributable to protonated molecules of intact, monooxygenated, and dioxygenated 2CEES (MH+, MOH+, and MO2H+, respectively) were observed. As ozone concentration was increased from zero to 30 ppm, the signal intensity of MH+ sharply decreased, that of MOH+ increased once and then decreased, and that of MO2H+ sharply increased until reaching a plateau. The signal intensity of MO2H+ at the plateau was 40 times higher than that of MH+ and 100 times higher than that of MOH+ in the case without in-line ozonation. Twenty-ppm ozone gas was adequate to give a linear calibration curve for 2CEES obtained by detecting the MO2H+ signal in the concentration range up to 60 ?g/m3, which is high enough for hygiene management. In the low concentration range lower than 3 ?g/m3, which is equal to the short-term exposure limit for HD, calibration plots unexpectedly fell off the linear calibration curve, but 0.6-?g/m3 vapor was actually detected with the signal-to-noise ratio of nine. Ozone was generated from instrumentation air by using a simple and inexpensive home-made generator. 2CEES was ozonated in 1-m extended sampling tube in only 1 s.

  9. Tricyclic Antidepressant Amitriptyline-induced Glial Cell Line-derived Neurotrophic Factor Production Involves Pertussis Toxin-sensitive G?i/o Activation in Astroglial Cells.

    PubMed

    Hisaoka-Nakashima, Kazue; Miyano, Kanako; Matsumoto, Chie; Kajitani, Naoto; Abe, Hiromi; Okada-Tsuchioka, Mami; Yokoyama, Akinobu; Uezono, Yasuhito; Morioka, Norimitsu; Nakata, Yoshihiro; Takebayashi, Minoru

    2015-05-29

    Further elaborating the mechanism of antidepressants, beyond modulation of monoaminergic neurotransmission, this study sought to elucidate the mechanism of amitriptyline-induced production of glial cell line-derived neurotrophic factor (GDNF) in astroglial cells. Previous studies demonstrated that an amitriptyline-evoked matrix metalloproteinase (MMP)/FGF receptor (FGFR)/FGFR substrate 2? (FRS2?)/ERK cascade is crucial for GDNF production, but how amitriptyline triggers this cascade remains unknown. MMP is activated by intracellular mediators such as G proteins, and this study sought to clarify the involvement of G protein signaling in amitriptyline-evoked GDNF production in rat C6 astroglial cells (C6 cells), primary cultured rat astrocytes, and normal human astrocytes. Amitriptyline-evoked GDNF mRNA expression and release were inhibited by pertussis toxin (PTX), a G?(i/o) inhibitor, but not by NF449, a G?(s) inhibitor, or YM-254890, a G?q inhibitor. The activation of the GDNF production cascade (FGFR/FRS2?/ERK) was also inhibited by PTX. Deletion of G?(?1) and G?(i3) by RNAi demonstrated that these G proteins play important roles in amitriptyline signaling. G protein activation was directly analyzed by electrical impedance-based biosensors (CellKey(TM) assay), using a label-free (without use of fluorescent proteins/probes or radioisotopes) and real time approach. Amitriptyline increased impedance, indicating G?(i/o) activation that was suppressed by PTX treatment. The impedance evoked by amitriptyline was not affected by inhibitors of the GDNF production cascade. Furthermore, FGF2 treatment did not elicit any effect on impedance, indicating that amitriptyline targets PTX-sensitive G?(i/o) upstream of the MMP/FGFR/FRS2?/ERK cascade. These results suggest novel targeting for the development of antidepressants. PMID:25869129

  10. Impacts of WIMP dark matter upon stellar evolution: main-sequence stars

    E-print Network

    Pat Scott; Malcolm Fairbairn; Joakim Edsjö

    2008-10-30

    The presence of large amounts of WIMP dark matter in stellar cores has been shown to have significant effects upon models of stellar evolution. We present a series of detailed grids of WIMP-influenced stellar models for main sequence stars, computed using the DarkStars code. We describe the changes in stellar structure and main sequence evolution which occur for masses ranging from 0.3 to 2.0 solar masses and metallicities from Z = 0.0003-0.02, as a function of the rate of energy injection by WIMPs. We then go on to show what rates of energy injection can be obtained using realistic orbital parameters for stars near supermassive black holes, including detailed considerations of dark matter halo velocity and density profiles. Capture and annihilation rates are strongly boosted when stars follow elliptical rather than circular orbits, causing WIMP annihilation to provide up to 100 times the energy of hydrogen fusion in stars at the Galactic centre.

  11. The Physics Case for Axions, WIMPs, WISPs and Other Weird Stuff

    E-print Network

    Jaeckel, Joerg

    2008-01-01

    We argue that there exists an excellent `physics case' motivating the search for axions, WIMPs, WISPs and other phenomena testable at low energies. This physics case arises from both experimental and observational evidence as well as the desire to test theoretical model building.

  12. Simultaneous Generation of WIMP Miracle-like Densities of Baryons and Dark Matter

    E-print Network

    John McDonald

    2015-03-05

    The observed density of dark matter is of the magnitude expected for a thermal relic weakly-interacting massive particle (WIMP). In addition, the observed baryon density is within an order of magnitude of the dark matter density. This suggests that the baryon density is physically related to a typical thermal relic WIMP dark matter density. We present a model which simultaneously generates thermal relic WIMP-like densities for both baryons and dark matter by modifying a large initial baryon asymmetry. Dark matter is due to O(100) GeV gauge singlet scalars produced in the annihilation of the O(TeV) coloured scalars which are responsible for the final thermal WIMP-like baryon asymmetry. The requirement of no baryon washout implies that there are two gauge singlet scalars. The low temperature transfer of the asymmetry to conventional baryons can be understood if the long-lived O(TeV) coloured scalars have large hypercharge, |Y| > 4/3. Production of such scalars at the LHC would be a clear signature of the model.

  13. Model-independent WIMP Scattering Responses and Event Rates: A Mathematica Package for Experimental Analysis

    E-print Network

    Nikhil Anand; A. Liam Fitzpatrick; W. C. Haxton

    2013-08-28

    The community's reliance on simplified descriptions of WIMP-nucleus interactions reflects the absence of analysis tools that integrate general theories of dark matter with standard treatments of nuclear response functions. To bridge this gap, we have constructed a public-domain Mathematica package for WIMP analyses based on our effective theory formulation. Script inputs are 1) the coefficients of the effective theory, through which one can characterize the low-energy consequences of arbitrary ultraviolet theories of WIMP interactions; and 2) one-body density matrices for commonly used targets, the most compact description of the relevant nuclear physics. The generality of the effective theory expansion guarantees that the script will remain relevant as new ultraviolet theories are explored; the use of density matrices to factor the nuclear physics from the particle physics will allow nuclear structure theorists to update the script as new calculations become available, independent of specific particle-physics contexts. The Mathematica package outputs the resulting response functions (and associated form factors) and also the differential event rate, once a galactic WIMP velocity profile is specified, and thus in its present form provides a complete framework for experimental analysis. The Mathematica script requires no a priori knowledge of the details of the non-relativistic effective field theory or nuclear physics, though the core concepts are reviewed here and in arXiv:1203.3542.

  14. Weighing Wimps with Kinks at Colliders: Invisible Particle Mass Measurements from Endpoints

    E-print Network

    Barr, Alan; Gripaios, Ben; Lester, Christopher G.

    2008-01-01

    stream_source_info 0711.4008v1.pdf.txt stream_content_type text/plain stream_size 85511 Content-Encoding UTF-8 stream_name 0711.4008v1.pdf.txt Content-Type text/plain; charset=UTF-8 Weighing Wimps with Kinks at Colliders...

  15. Reconstructing WIMP properties in direct detection experiments including galactic dark matter distribution uncertainties

    SciTech Connect

    Strigari, Louis E.; Trotta, Roberto E-mail: r.trotta@imperial.ac.uk

    2009-11-01

    We present a new method for determining Weakly Interacting Massive Particle (WIMP) properties in future tonne scale direct detection experiments which accounts for uncertainties in the Milky Way (MW) smooth dark matter distribution. Using synthetic data on the kinematics of MW halo stars matching present samples from the Sloan Digital Sky Survey, complemented by local escape velocity constraints, we demonstrate that the local dark matter density can be constrained to ? 20% accuracy. For low mass WIMPs, we find that a factor of two error in the assumed local dark matter density leads to a severely biased reconstruction of the WIMP spin-independent cross section that is incorrect at the 15? level. We show that this bias may be overcome by marginalizing over parameters that describe the MW potential, and use this formalism to project the accuracy attainable on WIMP properties in future 1 ton Xenon detectors. Our method can be readily applied to different detector technologies and extended to more detailed MW halo models.

  16. The Physics Case for Axions, WIMPs, WISPs and Other Weird Stuff

    E-print Network

    Joerg Jaeckel

    2008-09-18

    We argue that there exists an excellent `physics case' motivating the search for axions, WIMPs, WISPs and other phenomena testable at low energies. This physics case arises from both experimental and observational evidence as well as the desire to test theoretical model building.

  17. The Pressure of Misalignment Axions: a Difference from WIMPs in Galaxy Formation?

    E-print Network

    Sacha Davidson

    2014-10-18

    Two populations of axions can contribute to cold dark matter: the classical field produced via the misalignment mechanism, and the modes produced in the decay of strings. The classical field has extra pressure, as compared to WIMPs, which could have observable consequences in non-linear galaxy formation.

  18. Are direct search experiments sensitive to all spin-independent weakly interacting massive particles?

    PubMed

    Giuliani, F

    2005-09-01

    The common analysis of direct searches for spin-independent weakly interacting massive particles (WIMPs) assumes that a spin-independent WIMP couples with the same strength with both nucleons, i.e., that the spin-independent interaction is also fully isospin independent. Though in a fully isospin-dependent interaction scenario the spin-independent WIMP-nucleus cross section is strongly quenched, the leading experiments are still sensitive enough to set limits 1-2 orders of magnitude less stringent than those traditionally presented. In the isospin-dependent scenario the difference between the limits of CDMS-II and ZEPLIN-I is significantly reduced. Here, a model-independent framework is discussed and applied to obtain the current general model-independent limits. PMID:16196915

  19. Receptor-mediated increases in cytosolic Ca2+ in the human erythroleukaemia cell line involve pertussis toxin-sensitive and -insensitive pathways.

    PubMed Central

    Schwaner, I; Seifert, R; Schultz, G

    1992-01-01

    The pluripotent human erythroleukaemia cell line, HEL, possesses erythrocytic, megakaryocytic and macrophage-like properties. With respect to signal transduction, HEL cells have been used as a model system for platelets, but little attention has been paid to their phagocytic properties. We studied the effects of various receptor agonists on the intracellular free Ca2+ concentration ([Ca2+]i) in HEL cells. Thrombin, platelet-activating factor (PAF), ATP, UTP, prostaglandins E1 and E2 (PGE1 and PGE2), the PGE2 analogue sulprostone and the stable PGI2 analogues iloprost and cicaprost increased [Ca2+]i. ADP was less effective than ATP, and UDP was unable to increase [Ca2+]i. The increases in [Ca2+]i induced by thrombin, PAF, ATP, UTP, iloprost and cicaprost were pertussis toxin-insensitive, whereas the increases induced by PGE2 and sulprostone were completely inhibited by the toxin. The increase in [Ca2+]i induced by PGE1 was partially inhibited by pertussis toxin. PGE2 did not desensitize the increase in [Ca2+]i induced by iloprost, and vice versa. PGE1 desensitized the response to PGE2 and iloprost but not vice versa. Adrenaline potentiated the iloprost- but not the PGE2-induced rise in [Ca2+]i. The phorbol ester phorbol 12-myristate 13-acetate completely blocked the rise in [Ca2+]i induced by ATP and PGE1, whereas the increases induced by thrombin and PAF were only partially inhibited. Agonists increased [Ca2+]i through release from internal stores and sustained Ca2+ influx. Thrombin stimulated Mn2+ influx, which was blocked by Ni2+. Diltiazem, isradipine, gramicidin and 1-(beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl)-1H-imidazole hydrochloride (SK&F 96365) did not affect agonist-induced rises in [Ca2+]i. HEL cells contained substantial amounts of beta-glucuronidase which, however, could not be released, and they did not aggregate or generate superoxide. Our data suggest that: (1) HEL cells possess nucleotide receptors with properties similar to those of phagocytes; (2) they possess receptors for PGE2 and PGI2, and PGE1 is an agonist at both receptors; (3) agonist-induced increases in [Ca2+]i are mediated through pertussis toxin-sensitive as well as -insensitive signal transduction pathways; and (4) agonists increase [Ca2+]i by mobilization from internal stores and influx from the extracellular space through cation channels with properties similar to those of phagocytes and platelets. PMID:1310589

  20. Neutrinos from WIMP annihilations obtained using a full three-flavor Monte Carlo approach

    SciTech Connect

    Blennow, Mattias; Ohlsson, Tommy; Edsjoe, Joakim E-mail: edsjo@physto.se

    2008-01-15

    Weakly interacting massive particles (WIMPs) are one of the main candidates for making up the dark matter in the Universe. If these particles make up the dark matter, then they can be captured by the Sun or the Earth, sink to the respective cores, annihilate, and produce neutrinos. Thus, these neutrinos can be a striking dark matter signature at neutrino telescopes looking towards the Sun and/or the Earth. Here, we improve previous analyses on computing the neutrino yields from WIMP annihilations in several respects. We include neutrino oscillations in a full three-flavor framework as well as all effects from neutrino interactions on the way through the Sun (absorption, energy loss, and regeneration from tau decays). In addition, we study the effects of non-zero values of the mixing angle {theta}{sub 13} as well as the normal and inverted neutrino mass hierarchies. Our study is performed in an event-based setting which makes these results very useful both for theoretical analyses and for building a neutrino telescope Monte Carlo code. All our results for the neutrino yields, as well as our Monte Carlo code, are publicly available. We find that the yield of muon-type neutrinos from WIMP annihilations in the Sun is enhanced or suppressed, depending on the dominant WIMP annihilation channel. This effect is due to an effective flavor mixing caused by neutrino oscillations. For WIMP annihilations inside the Earth, the distance from source to detector is too small to allow for any significant amount of oscillations at the neutrino energies relevant for neutrino telescopes.

  1. First measurement of the Head-Tail directional nuclear recoil signature at energies relevant to WIMP dark matter searches

    E-print Network

    S. Burgos; E. Daw; J. Forbes; C. Ghag; M. Gold; C. Hagemann; V. A. Kudryavtsev; T. B. Lawson; D. Loomba; P. Majewski; D. Muna; A. StJ. Murphy; G. G. Nicklin; S. M. Paling; A. Petkov; S. J. S. Plank; M. Robinson; N. Sanghi; D. P. Snowden-Ifft; N. J. C. Spooner; J. Turk; E. Tziaferi

    2008-09-10

    We present first evidence for the so-called Head-Tail asymmetry signature of neutron-induced nuclear recoil tracks at energies down to 1.5 keV/amu using the 1m^3 DRIFT-IIc dark matter detector. This regime is appropriate for recoils induced by Weakly Interacting Massive Particle (WIMPs) but one where the differential ionization is poorly understood. We show that the distribution of recoil energies and directions induced here by Cf-252 neutrons matches well that expected from massive WIMPs. The results open a powerful new means of searching for a galactic signature from WIMPs.

  2. Differential sensitivity to x-ray of chromosomes of blood T-lymphocytes and B-and T-cell lines.

    PubMed

    Shiraishi, Y; Minowada, J; Sanberg, A A

    1976-07-01

    Normal T-lymphocytes, B-cell line (CCRF-SB) and T-cell line (CCRF-HSB-2) cells, all diploid in their chromosome constitution, were exposed in vitro to various doses of X-ray and analyzed at their first mitotic division for structural chromosome abnormalities. The irradiation effects were determined also by a viability test of the cells, using trypan blue dye. The irradiated T-cell line (CCRF-HSB-2) showed a remarkably high frequency of chromosome aberrations, including chromosome and chromatid deletions, chromatid exchanges, dicentrics, rings and acentric fragments. On the other hand, the chromosome aberrations observed in the irradiated B-cell line and normal T-lymphocytes consisted mainly of dicentrics, rings, deletions and acentric fragments; the frequency of chromosome and chromatid deletions was low as compared to that of the T-cell line. The cell viability test showed a singificantly higher percent reduction of viable cells at every dose of X-ray in the irradiated T-cell line than in the B-cell line or the normal T-lymphocytes. It is possible that the increased radiosensitivity of the T-cell line is related to the original malignant nature of the cells, which originated from the lymphocytes of a patient with acute lymphoblastic leukemia. PMID:1085743

  3. Effects of residue background events in direct dark matter detection experiments on the determination of the WIMP mass

    SciTech Connect

    Chou, Yu-Ting; Shan, Chung-Lin E-mail: clshan@mail.ncku.edu.tw

    2010-08-01

    In the earlier work on the development of a model-independent data analysis method for determining the mass of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the determination of the WIMP mass, the maximal acceptable fraction of residue background events in the analyzed data sets of O(50) total events is ? 20%, for background windows of the entire experimental possible energy ranges, or in low energy ranges; while, for background windows in relatively higher energy ranges, this maximal acceptable fraction of residue background events can not be larger than ? 10%. For a WIMP mass of 100 GeV with 20% background events in the windows of the entire experimental possible energy ranges, the reconstructed WIMP mass and the 1? statistical uncertainty are ? 97GeV{sup +61%}{sub ?35%} ( ? 94GeV{sup +55%}{sub ?33%} for background-free data sets)

  4. Effects of Residue Background Events in Direct Dark Matter Detection Experiments on the Determination of the WIMP Mass

    E-print Network

    Yu-Ting Chou; Chung-Lin Shan

    2010-08-06

    In the earlier work on the development of a model-independent data analysis method for determining the mass of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the determination of the WIMP mass, the maximal acceptable fraction of residue background events in the analyzed data sets of O(50) total events is ~20%, for background windows of the entire experimental possible energy ranges, or in low energy ranges; while, for background windows in relatively higher energy ranges, this maximal acceptable fraction of residue background events can not be larger than ~10%. For a WIMP mass of 100 GeV with 20% background events in the windows of the entire experimental possible energy ranges, the reconstructed WIMP mass and the 1-sigma statistical uncertainty are ~97 GeV^{+61%}_{-35%} (~94 GeV^{+55%}_{-33%} for background-free data sets).

  5. Dark matter in the solar system I: The distribution function of WIMPs at the Earth from solar capture

    E-print Network

    Annika H. G. Peter

    2009-02-09

    The next generation of dark matter (DM) direct detection experiments and neutrino telescopes will probe large swaths of dark matter parameter space. In order to interpret the signals in these experiments, it is necessary to have good models of both the halo DM streaming through the solar system and the population of DM bound to the solar system. In this paper, the first in a series of three on DM in the solar system, we present simulations of orbits of DM bound to the solar system by solar capture in a toy solar system consisting of only the Sun and Jupiter, assuming that DM consists of a single species of weakly interacting massive particle (WIMP). We describe how the size of the bound WIMP population depends on the WIMP mass, spin-independent cross section, and spin-dependent cross section. Using a standard description of the Galactic DM halo, we find that the maximum enhancement to the direct detection event rate, consistent with current experimental constraints on the WIMP-nucleon cross section, is < 1% relative to the event rate from halo WIMPs, while the event rate from neutrinos from WIMP annihilation in the center of the Earth is unlikely to meet the threshold of next-generation, km^3-sized (IceCube, KM3NeT) neutrino telescopes.

  6. WIMP Searches at the ILC using a model-independent Approach

    E-print Network

    C. Bartels; J. List

    2009-01-30

    In this note the ILC's capabilities for detecting WIMPs and measuring their properties are studied. The expected signal cross section is derived in a model-independent way from the observed relic density of Dark Matter. Signal events are detected by means of initial state radiation (ISR). The study is performed with a full simulation of the ILD detector. The results show that WIMPs are observable at the ILC if their coupling to electrons is not too small (O(0.1)). Their masses can be measured with a precision of 1 to 2 GeV. The accessible phase space can be increased significantly using polarised beams, especially if the positrons are polarised as well.

  7. A novel way of constraining WIMPs annihilations in the Sun: MeV neutrinos

    SciTech Connect

    Bernal, Nicolás; Martín-Albo, Justo; Palomares-Ruiz, Sergio E-mail: justo.martin-albo@ific.uv.es

    2013-08-01

    Annihilation of dark matter particles accumulated in the Sun would produce a flux of high-energy neutrinos whose prospects of detection in neutrino telescopes and detectors have been extensively discussed in the literature. However, for annihilations into Standard Model particles, there would also be a flux of neutrinos in the MeV range from the decays at rest of muons and positively charged pions. These low-energy neutrinos have never been considered before and they open the possibility to also constrain dark matter annihilation in the Sun into e{sup +}e{sup ?}, ?{sup +}?{sup ?} or light quarks. Here we perform a detailed analysis using the recent Super-Kamiokande data in the few tens of MeV range to set limits on the WIMP-nucleon scattering cross section for different annihilation channels and computing the evaporation rate of WIMPs from the Sun for all values of the scattering cross section in a consistent way.

  8. Silicon photonic crystal microarrays for high throughput label-free detection of lung cancer cell line lysates with sensitivity and specificity

    NASA Astrophysics Data System (ADS)

    Chakravarty, Swapnajit; Lai, Wei-Cheng; Zou, Yi; Gemmill, Robert M.; Chen, Ray T.

    2013-03-01

    Detection of biomolecules on microarrays based on label-free on-chip optical biosensors is very attractive since this format avoids complex chemistries caused by steric hindrance of labels. Application areas include the detection of cancers and allergens, and food-borne pathogens to name a few. We have demonstrated photonic crystal microcavity biosensors with high sensitivity down to 1pM concentrations (67pg/ml). High sensitivities were achieved by slow light engineering which reduced the radiation loss and increased the stored energy in the photonic crystal microcavity resonance mode. Resonances with high quality factor Q~26,760 in liquid ambient, coupled with larger optical mode volumes allowed enhanced interaction with the analyte biomolecules which resulted in sensitivities down to 10 cells per micro-liter to lung cancer cell lysates. The specificity of detection was ensured by multiplexed detections from multiple photonic crystal microcavities arrayed on the arms of a multimode interference power splitter. Specific binding interactions and control experiments were performed simultaneously at the same instant of time with the same 60 microliter sample volume. Specificity is further ensured by sandwich assay methods in the multiplexed experiment. Sandwich assay based amplification increased the sensitivity further resulting in the detection of lung cancer cell lysates down to concentrations of 2 cells per micro-liter. The miniaturization enabled by photonic crystal biosensors coupled with waveguide interconnected layout thus offers the potential of high throughput proteomics with high sensitivity and specificity.

  9. Effect of Galium verum aqueous extract on growth, motility and gene expression in drug-sensitive and -resistant laryngeal carcinoma cell lines.

    PubMed

    Schmidt, Marianne; Scholz, Claus-Juergen; Gavril, Georgiana-Luminita; Otto, Clemens; Polednik, Christine; Roller, Jeanette; Hagen, Rudolf

    2014-03-01

    Galium verum, also known as Lady's Bedstraw, is a herbaceous perennial plant of the family Rubiaceae, native to Europe and Asia and used in traditional medicine as an anticancer medicine. It is used as a decoction in most traditional recipes, applied externally as well as internally. We produced a Galium verum decoction and applied it in vitro to chemosensitive (Hep-2 and HLaC79) and chemoresistant, P-glycoprotein-overexpressing (Hep2-Tax, HLaC79-Tax) laryngeal carcinoma cell lines. It could be demonstrated that Galium aqueous extract is cytotoxic for all cell lines. A detailed spheroid-based 3D invasion analysis of Hep2 and Hep2-Tax in semisolid collagen gels and on different extracellular matrix coatings was performed, which showed an inhibition of invasion by sublethal concentrations of Galium decoction and proved to be even more pronounced in the more aggressively invading chemoresistant Hep2-Tax cell line. Gelatinolytic activity of MMP-2 was downregulated in three of the four cell lines. Angiogenesis (endothelial tube formation) in contrast, was not affected by Galium aqueous extract. Gene expression array on HLaC79 and Hep2 cell lines treated with Galium decoction vs. untreated controls revealed no unique pathway activation patterns in these cells. Results are discussed with respect to the use of herbal drugs as a preventive and/or a concomitant therapeutic approach in head and neck cancer. PMID:24366449

  10. Dual regulation of skin sensitizer-induced HMOX1 expression by Bach1 and Nrf2: Comparison to regulation of the AKR1C2-ARE element in the KeratinoSens cell line.

    PubMed

    Emter, Roger; Natsch, Andreas

    2015-11-01

    Heme oxygenase (decycling) 1 (HMOX1) is the most consistently found genetic marker induced by skin sensitizers. HMOX1 is often referred to as typical gene regulated by nuclear factor erythroid 2-related factor 2 (Nrf2), however, it is also regulated by other DNA-binding factors, including BTB and CNC homolog 1 (Bach1). The KeratinoSens™ assay is the first validated in vitro assay for sensitizers that measures gene induction. It is based on luciferase expression regulated by the antioxidant response element (ARE) of the aldoketoreductase 1C2 (AKR1C2) gene. Luciferase upregulation is dependent on Nrf2, while HMOX1 upregulation is only partially Nrf2-dependent. Thus, sensitizer-dependent activation of HMOX1 may integrate multiple signals thereby providing additional information. We constructed reporter cell lines containing the full HMOX1 regulatory region or the HMOX1-ARE sequence and compared them with the construct containing the AKR1C2-ARE sequence. Induction of the AKR1C2-ARE depends on Nrf2, but not on the repressor Bach1. Results obtained with HMOX1-ARE and the full HMOX1 promoter indicate that, within the HMOX1 promoter, the HMOX1-ARE is sufficient to explain the induction by sensitizers and that (i) inhibiting Bach1 leads to strong basal expression, (ii) fold-induction by sensitizers above this level is reduced in the absence of Bach1 and (iii) these constructs are less dependent on Nrf2 as compared to the AKR1C2-ARE. Nevertheless, congruent dose response curves for luciferase activity were obtained with all constructs. Thus, while sensitizer-induced HMOX1 activation is dependent on Nrf2 and Bach1, all constructs give identical information for the in vitro prediction of the sensitization potential. PMID:26244607

  11. Reevaluation of spin-dependent WIMP-proton interactions as an explanation of the DAMA data

    NASA Astrophysics Data System (ADS)

    Del Nobile, Eugenio; Gelmini, Graciela B.; Georgescu, Andreea; Huh, Ji-Haeng

    2015-08-01

    We reexamine the interpretation of the annual modulation signal observed by the DAMA experiment as due to WIMPs with a spin-dependent coupling mostly to protons. We consider both axial-vector and pseudo-scalar couplings, and elastic as well as endothermic and exothermic inelastic scattering. We conclude that the DAMA signal is in strong tension with null results of other direct detection experiments, particularly PICASSO and KIMS.

  12. WIMPs search by exclusive measurements with thin multilayer NaI(Tl) scintillators (PICO-LON)

    E-print Network

    K. Fushimi; H. Kawasuso; K. Yasuda; Y. Kameda; N. Koori; S. Nakayama; K. Ichihara; M. Nomachi; S. Umehara; R. Hazama; S. Yoshida; H. Ejiri; K. Imagawa; H. Ito

    2006-12-01

    The WIMPs search project PICO-LON has been started with multilayer thin NaI(Tl) crystals. The thin (0.05cm) and wide area (5cmx5cm) NaI(Tl) crystals was successfully developed. The performances of thin NaI(Tl) scintillator was measured and they showed good energy resolution (20% at 60keV) and good position resolution (20% in 5cmx5cm wider area).

  13. Reevaluation of spin-dependent WIMP-proton interactions as an explanation of the DAMA data

    E-print Network

    Eugenio Del Nobile; Graciela B. Gelmini; Andreea Georgescu; Ji-Haeng Huh

    2015-07-10

    We reexamine the interpretation of the annual modulation signal observed by the DAMA experiment as due to WIMPs with a spin-dependent coupling mostly to protons. We consider both axial-vector and pseudo-scalar couplings, and elastic as well as endothermic and exothermic inelastic scattering. We conclude that the DAMA signal is in strong tension with null results of other direct detection experiments, particularly PICASSO and KIMS.

  14. Nuclear ?-terms and Scalar-Isoscalar WIMP-Nucleus Interactions from Lattice QCD

    E-print Network

    S. R. Beane; S. D. Cohen; W. Detmold; H. -W. Lin; M. J. Savage

    2015-03-18

    It has been argued that the leading scalar-isoscalar WIMP-nucleus interactions receive parametrically enhanced contributions in the context of nuclear effective field theories. These contributions arise from meson-exchange currents (MECs) and potentially modify the impulse approximation estimates of these interactions by 10--60%. We point out that these MECs also contribute to the quark mass dependence of nuclear binding energies, that is, nuclear \\sigma-terms. In this work, we use recent lattice QCD calculations of the binding energies of the deuteron, He-3 and He-4 at pion masses near 500 MeV and 800 MeV, combined with the experimentally determined binding energies at the physical point, to provide approximate determinations of the \\sigma-terms for these light nuclei. For each nucleus, we find that the deviation of the corresponding nuclear \\sigma-term from the single-nucleon estimate is at the few percent level, in conflict with the conjectured enhancement. As a consequence, lattice QCD calculations currently indicate that the cross sections for scalar-isoscalar WIMP-nucleus interactions arising from fundamental WIMP interactions with quarks do not suffer from significant uncertainties due to enhanced meson-exchange currents.

  15. Probing the local velocity distribution of WIMP dark matter with directional detectors

    SciTech Connect

    Lee, Samuel K.; Peter, Annika H.G. E-mail: annika.peter@uci.edu

    2012-04-01

    We explore the ability of directional nuclear-recoil detectors to constrain the local velocity distribution of weakly interacting massive particle (WIMP) dark matter by performing Bayesian parameter estimation on simulated recoil-event data sets. We discuss in detail how directional information, when combined with measurements of the recoil-energy spectrum, helps break degeneracies in the velocity-distribution parameters. We also consider the possibility that velocity structures such as cold tidal streams or a dark disk may also be present in addition to the Galactic halo. Assuming a CF{sub 4} detector with a 30-kg-yr exposure, a 50-GeV WIMP mass, and a WIMP-nucleon spin-dependent cross-section of 10{sup ?3}pb, we show that the properties of a cold tidal stream may be well constrained. However, measurement of the parameters of a dark-disk component with a low lag speed of ? 50km/s may be challenging unless energy thresholds are improved.

  16. WIMP-nucleon cross-section results from the second science run of ZEPLIN-III

    E-print Network

    D. Yu. Akimov; H. M. Araujo; E. J. Barnes; V. A. Belov; A. Bewick; A. A. Burenkov; V. Chepel; A. Currie; L. DeViveiros; B. Edwards; C. Ghag; A. Hollingsworth; M. Horn; W. G. Jones; G. E. Kalmus; A. S. Kobyakin; A. G. Kovalenko; V. N. Lebedenko; A. Lindote; M. I. Lopes; R. Luscher; P. Majewski; A. StJ. Murphy; F. Neves; S. M. Paling; J. Pinto da Cunha; R. Preece; J. J. Quenby; L. Reichhart; P. R. Scovell; C. Silva; V. N. Solovov; N. J. T. Smith; V. N. Stekhanov; T. J. Sumner; C. Thorne; R. J. Walker

    2011-12-16

    We report experimental upper limits on WIMP-nucleon elastic scattering cross sections from the second science run of ZEPLIN-III at the Boulby Underground Laboratory. A raw fiducial exposure of 1,344 kg.days was accrued over 319 days of continuous operation between June 2010 and May 2011. A total of eight events was observed in the signal acceptance region in the nuclear recoil energy range 7-29 keV, which is compatible with background expectations. This allows the exclusion of the scalar cross-section above 4.8E-8 pb near 50 GeV/c^2 WIMP mass with 90% confidence. Combined with data from the first run, this result improves to 3.9E-8 pb. The corresponding WIMP-neutron spin-dependent cross-section limit is 8.0E-3 pb. The ZEPLIN programme reaches thus its conclusion at Boulby, having deployed and exploited successfully three liquid xenon experiments of increasing reach.

  17. Nuclear ? terms and scalar-isoscalar WIMP-nucleus interactions from lattice QCD

    NASA Astrophysics Data System (ADS)

    Beane, S. R.; Cohen, S. D.; Detmold, W.; Lin, H.-W.; Savage, M. J.

    2014-04-01

    It has been argued that the leading scalar-isoscalar weakly interacting massive particle (WIMP) -nucleus interactions receive parametrically enhanced contributions in the context of nuclear effective field theories [1]. These contributions arise from meson-exchange currents (MECs) and potentially modify the impulse approximation estimates of these interactions by 10%-60%. We point out that these MECs also contribute to the quark mass dependence of nuclear binding energies, that is, nuclear ? terms. In this work, we use recent lattice QCD calculations of the binding energies of the deuteron, He3 and He4 at pion masses near 500 and 800 MeV, combined with the experimentally determined binding energies at the physical point, to provide approximate determinations of the ? terms for these light nuclei. For each nucleus, we find that the deviation of the corresponding nuclear ? term from the single-nucleon estimate is at the few-percent level, in conflict with the conjectured enhancement. As a consequence, lattice QCD calculations currently indicate that the cross sections for scalar-isoscalar WIMP-nucleus interactions arising from fundamental WIMP interactions with quarks do not suffer from significant uncertainties due to enhanced MECs.

  18. Halo-independent analysis of direct detection data for light WIMPs

    SciTech Connect

    Nobile, Eugenio Del; Gelmini, Graciela B.; Huh, Ji-Haeng; Gondolo, Paolo E-mail: gelmini@physics.ucla.edu E-mail: jhhuh@physics.ucla.edu

    2013-10-01

    We present a halo-independent analysis of direct detection data on ''light WIMPs'', i.e. weakly interacting massive particles with mass close to or below 10 GeV/c{sup 2}. We include new results from silicon CDMS detectors (bounds and excess events), the latest CoGeNT acceptances, and recent measurements of low sodium quenching factors in NaI crystals. We focus on light WIMPs with spin-independent isospin-conserving and isospin-violating interactions with nucleons. For these dark matter candidates we find that a low quenching factor would make the DAMA modulation incompatible with a reasonable escape velocity for the dark matter halo, and that the tension among experimental data tightens in both the isospin-conserving and isospin-violating scenarios. We also find that a new although milder tension appears between the CoGeNT and DAMA annual modulations on one side and the silicon excess events on the other, in that it seems difficult to interpret them as the modulated and unmodulated aspects of the same WIMP dark matter signal.

  19. Enhanced sensitivity to dark matter self-annihilations in the Sun using neutrino spectral information

    SciTech Connect

    Rott, C.; Tanaka, T.; Itow, Y. E-mail: ttanaka@stelab.nagoya-u.ac.jp

    2011-09-01

    Self-annihilating dark matter gravitationally captured by the Sun could yield observable neutrino signals at current and next generation neutrino detectors. By exploiting such signals, neutrino detectors can probe the spin-dependent scattering of weakly interacting massive particles (WIMPs) with nucleons in the Sun. We describe a method how to convert constraints on neutrino fluxes to a limit on the WIMP-nucleon scattering cross section. In this method all neutrino flavors can be treated in a very similar way. We study the sensitivity of neutrino telescopes for Solar WIMP signals using vertex contained events and find that this detection channel is of particular importance in the search for low mass WIMPs. We obtain highly competitive sensitivities with all neutrino flavor channels for a Megaton sized detector through the application of basic spectral selection criteria. Best results are obtained with the electron neutrino channel. We discuss associated uncertainties and provide a procedure how to treat them for analyses in a consistent way.

  20. Neutrinos from WIMP annihilation in the Sun : Implications of a self-consistent model of the Milky Way's dark matter halo

    E-print Network

    Susmita Kundu; Pijushpani Bhattacharjee

    2012-05-21

    Upper limits on the spin-independent (SI) as well as spin-dependent (SD) elastic scattering cross sections of WIMPs with protons, imposed by the Super-Kamiokande (S-K) upper limit on the neutrino flux from WIMP annihilation in the Sun, and their compatibility with the "DAMA-compatible" regions of the WIMP parameter space within which the annual modulation signal observed by the DAMA/LIBRA experiment is compatible with the null results of other direct detection experiments, are studied within the frame work of a self-consistent model of the finite-size dark matter (DM) halo of the Galaxy, the parameters of which are determined by a fit to the rotation curve data of the Galaxy. We find that the S-K implied upper limits on the WIMP-proton elastic cross section as a function of WIMP mass impose stringent restrictions on the branching fractions of the various WIMP annihilation channels. For SI interaction, while the S-K upper limits are consistent with the DAMA-compatible region of the WIMP parameter space if the WIMPs annihilate dominantly to $\\bbarb$\\ and/or $\\cbarc$, portions of the DAMA-compatible region can be excluded if WIMP annihilations to $\\tautau$ and $\

  1. Establishment of a cell line from the ash and privet borer beetle Tylonotus bimaculatus Haldeman and assessment of its sensitivity to diacylhydrazine insecticides.

    PubMed

    Wen, Fayuan; Caputo, Guido; Hooey, Sharon; Bowman, Susan; Pinkney, Kristine; Krell, Peter J; Arif, Basil; Doucet, Daniel

    2015-10-01

    A novel cell line, NRCAN-Tb521, was developed from larvae of the longhorn beetle Tylonotus bimaculatus (Coleoptera: Cerambycidae), a pest of North American ash trees. The cell line has been successfully passaged more than 50 times and displayed very strong attachment to the substrate and a modal chromosomal count distribution of 19. Sequencing of a 649 bp fragment of the mitochondrial cytochrome oxidase I gene confirmed the identity of NRCAN-Tb521 as T. bimaculatus. The response of the cell line to 20-hydroxyecdysone and diacylhydrazine ecdysone agonist insecticides was also studied. At 10(-6) M, 20-hydroxyecdysone, tebufenozide, methoxyfenozide and halofenozide triggered the production of numerous filamentous cytoplasmic extensions, and the cells tended to form aggregates, indicative of a cell differentiation response. This response was followed by a strong decrease in viability after 4 d. Reverse transcription polymerase chain reaction (PCR) experiments and sequencing of PCR fragments showed that the 20E receptor gene EcR is expressed in the cells and that 20E, tebufenozide, methoxyfenozide and halofenozide also induce the expression of the nuclear hormone receptor gene HR3. This report establishes that NRCAN-Tb521 is a valuable in vitro model to study effects of ecdysone agonists in wood-boring cerambycids. PMID:25952767

  2. Direct detection of WIMPs: implications of a self-consistent truncated isothermal model of the Milky Way's dark matter halo

    SciTech Connect

    Chaudhury, Soumini

    2010-09-01

    Direct detection of Weakly Interacting Massive Particle (WIMP) candidates of Dark Matter (DM) is studied within the context of a self-consistent truncated isothermal model of the finite-size dark halo of the Galaxy. The halo model, based on the ''King model'' of the phase space distribution function of collisionless DM particles, takes into account the modifications of the phase-space structure of the halo due to the gravitational influence of the observed visible matter in a self-consistent manner. The parameters of the halo model are determined by a fit to a recently determined circular rotation curve of the Galaxy that extends up to ? 60 kpc. Unlike in the Standard Halo Model (SHM) customarily used in the analysis of the results of WIMP direct detection experiments, the velocity distribution of the WIMPs in our model is non-Maxwellian with a cut-off at a maximum velocity that is self-consistently determined by the model itself. For our halo model that provides the best fit to the rotation curve data, the 90% C.L. upper limit on the WIMP-nucleon spin-independent cross section from the recent results of the CDMS-II experiment, for example, is ? 5.3 × 10{sup ?8} pb at a WIMP mass of ? 71 GeV. We also find, using the original 2-bin annual modulation amplitude data on the nuclear recoil event rate seen in the DAMA experiment, that there exists a range of small WIMP masses, typically ? 2–16 GeV, within which DAMA collaboration's claimed annual modulation signal purportedly due to WIMPs is compatible with the null results of other experiments. These results, based as they are on a self-consistent model of the dark matter halo of the Galaxy, strengthen the possibility of low-mass (?<10 GeV) WIMPs as a candidate for dark matter as indicated by several earlier studies performed within the context of the SHM. A more rigorous analysis using DAMA bins over smaller intervals should be able to better constrain the ''DAMA regions'' in the WIMP parameter space within the context of our model.

  3. The Stream algorithm: computationally efficient ridge-regression via Bayesian model averaging, and applications to pharmacogenomic prediction of cancer cell line sensitivity.

    PubMed

    Neto, Elias Chaibub; Jang, In Sock; Friend, Stephen H; Margolin, Adam A

    2014-01-01

    Computational efficiency is important for learning algorithms operating in the "large p, small n" setting. In computational biology, the analysis of data sets containing tens of thousands of features ("large p"), but only a few hundred samples ("small n"), is nowadays routine, and regularized regression approaches such as ridge-regression, lasso, and elastic-net are popular choices. In this paper we propose a novel and highly efficient Bayesian inference method for fitting ridge-regression. Our method is fully analytical, and bypasses the need for expensive tuning parameter optimization, via cross-validation, by employing Bayesian model averaging over the grid of tuning parameters. Additional computational efficiency is achieved by adopting the singular value decomposition reparametrization of the ridge-regression model, replacing computationally expensive inversions of large p × p matrices by efficient inversions of small and diagonal n × n matrices. We show in simulation studies and in the analysis of two large cancer cell line data panels that our algorithm achieves slightly better predictive performance than cross-validated ridge-regression while requiring only a fraction of the computation time. Furthermore, in comparisons based on the cell line data sets, our algorithm systematically out-performs the lasso in both predictive performance and computation time, and shows equivalent predictive performance, but considerably smaller computation time, than the elastic-net. PMID:24297531

  4. A search for WIMPs and tests of local dark matter velocity distributions with the CoGeNT public dataset

    NASA Astrophysics Data System (ADS)

    Bellis, Matthew; Kelso, Chris; Collar, Juan; Fields, Nicole

    2014-03-01

    Since December 2009, the CoGeNT experiment has recorded interactions in the detector with the goal of either detecting dark matter or setting stringent limits on the mass and cross section of these particles, assuming that dark matter is a form of WIMP (Weakly Interacting Massive Particle). The collaboration has made public this dataset to the broader community and this analysis is based on that dataset. We perform an unbinned, maximum likelihood fit to the data, accounting for known backgrounds and systematic effects. We model the WIMP signal, parametrized by energy deposition and time of year, mass, cross-section, and choice of local WIMP velocity distribution. The velocity distribution is modeled with a Maxwellian-Boltzman distribution, as well as more directional streams. The current status of this analysis will be presented.

  5. In-Line Separation by Capillary Electrophoresis Prior to Analysis by Top-Down Mass Spectrometry Enables Sensitive Characterization of Protein Complexes

    PubMed Central

    2015-01-01

    Intact protein analysis via top-down mass spectrometry (MS) provides a bird’s eye view over the protein complexes and complex protein mixtures with the unique capability of characterizing protein variants, splice isoforms, and combinatorial post-translational modifications (PTMs). Here we applied capillary electrophoresis (CE) through a sheathless CE–electrospray ionization interface coupled to an LTQ Velos Orbitrap Elite mass spectrometer to analyze the Dam1 complex from Saccharomyces cerevisiae. We achieved a 100-fold increase in sensitivity compared to a reversed-phase liquid chromatography coupled MS analysis of recombinant Dam1 complex with a total loading of 2.5 ng (12 amol). N-terminal processing forms of individual subunits of the Dam1 complex were observed as well as their phosphorylation stoichiometry upon Mps1p kinase treatment. PMID:25382489

  6. Strong sensitivity of x-ray emission lines following charge exchange between highly charged ions and H (1 s ) in weakly screened media

    NASA Astrophysics Data System (ADS)

    Cariatore, N. D.; Otranto, S.

    2015-11-01

    We use the classical trajectory Monte Carlo method to analyze charge exchange processes between fully stripped projectiles with H (1 s ) in a screened environment at impact energies in the range 18 eV/amu to 10 keV/amu. For Fe+26 projectiles, (n ,l )-state selective charge exchange and line emission cross sections are presented for Debye screening lengths from 15 a.u. up to the unscreened case limit. At low-impact energies, a strong dependence of the hardness ratio on the Debye screening length is found. We show that such strong dependence also evidences itself for Ne+10,P+15,Ar+18, and Kr+36 projectiles. Clear indications of this dependence are noticeable in the photonic spectra even for large screening lengths (˜100 a.u.).

  7. Calcitonin gene-related peptide rapidly inhibits calcium uptake in osteoblastic cell lines via activation of adenosine triphosphate-sensitive potassium channels.

    PubMed

    Kawase, T; Howard, G A; Roos, B A; Burns, D M

    1996-03-01

    In certain neurons, alternative RNA processing generates calcitonin gene-related peptide (CGRP) from the same gene that encodes the hormone calcitonin. As CGRP-containing nerve fibers are prominent in skeleton, we evaluated the effects of CGRP on osteoblasts. Because the vasodilatory effect of neural CGRP in smooth muscle probably involves inhibition of unstimulated Ca2+ uptake, we examined the acute effects of CGRP on this parameter in rat osteoblastic cells. CGRP inhibits 45Ca2+ uptake in both UMR 106 osteosarcoma and RCOB-3 osteoblastic cells. This inhibition is rapid (0.5 min), occurs with an EC50 of 1 nM, and cannot be demonstrated in the presence of 0.1 mM diltiazem, a blocker of voltage-dependent Ca2+ channels. Depolarization of bone cells with high extracellular potassium (K+) also blocks the effect of CGRP on 45Ca2+ uptake, suggesting a central role for K+ channels in mediating this action. In agreement with this hypothesis, the effect of CGRP is blocked by 1 microM glybenclamide, a specific inhibitor of ATP-sensitive potassium (K(ATP)) channels, or by pretreatment of cells with 1 mM iodoacetic acid to deplete intracellular ATP. Blocking Ca2+-activated potassium channels with 1 mM tetraethylammonium does not prevent CGRP's effect. Pinacidil, a specific activator of K(ATP) channels, mimics CGRP's effect. Both CGRP and pinacidil also produce a small significant stimulation of cellular Ca2+ efflux in UMR 106 cells. These data suggest that inhibition of diltiazem-sensitive Ca2+ channels occurs secondary to the hyperpolarization engendered by CGRP activation of K(ATP) channels in osteoblastic cells, an effect similar to that of CGRP on smooth muscle cells. PMID:8603612

  8. The Search for Milky Way Halo Substructure WIMP Annihilations Using the GLAST LAT

    SciTech Connect

    Wai, Larry; /SLAC

    2007-02-05

    The GLAST LAT Collaboration is one among several experimental groups, covering a wide range of approaches, pursuing the search for the nature of dark matter. The GLAST LAT has the unique ability to find new sources of high energy gamma radiation emanating directly from WIMP annihilations in situ in the universe. Using it's wide band spectral and full sky spatial capabilities, the GLAST LAT can form ''images'' in high energy gamma-rays of dark matter substructures in the gamma-ray sky. We describe a preliminary feasibility study for indirect detection of milky way dark matter satellites using the GLAST LAT.

  9. GeV WIMPs scattering off of OH impurities cannot explain the DAMA signal

    SciTech Connect

    Profumo, Stefano; Queiroz, Farinaldo S. E-mail: fdasilva@ucsc.edu

    2014-05-01

    In the presence of OH impurities in the DAMA crystals, GeV-scale WIMPs elastically scattering off of hydrogen nuclei with a spin independent cross section of ?10{sup ?33}cm{sup 2} might explain the annual modulation observed by the DAMA experiment, while being consistent with other direct dark matter searches, as scattering would occur at energies below the energy threshold of other detectors. In this work we examine this possibility and show that, independent of the level of OH impurities in the DAMA crystals, for several reasons this scenario does not provide a viable explanation to the DAMA signal.

  10. Phase space distribution of halo particles and detection of WIMPS. [weakly interacting massive particles

    NASA Technical Reports Server (NTRS)

    Ryu, Dongsu; Perez, Armando

    1991-01-01

    We calculate the velocity distribution of halo particles using realistic models for the density profiles of the Galactic disk, spheroid, and halo components. We get the resulting velocity distribution, which is different from the Maxwellian distribution of isothermal halo. We investigate the consequences concerning the time averaged count rate and the amplitude of the annual modulation in WIMPS detection experiments. Compared to the previous estimate based on the Maxwellian distribution, the time averaged count rate is up to 40 percent larger. On the other hand, the amplitude of the annual modulation is up to a factor of two larger.

  11. Directional scintillation detector for the detection of the wind of WIMPs

    E-print Network

    Y. Shimizu; M. Minowa; H. Sekiya; Y. Inoue

    2002-09-02

    The quenching factor of the proton recoil in the stilbene scintillator was measured with a 252Cf neutron source and was found to be 0.1 - 0.17 in the recoil energy range between 300 keV and 3 MeV. It was found to depend on the direction of the recoil proton. The directional anisotropy of the quenching factor could be used to detect the wind of the WIMPs caused by the motion of the earth around the galactic center.

  12. The search for Milky Way halo substructure WIMP annihilations using the GLAST LAT

    E-print Network

    Lawrence Wai; GLAST LAT Collaboration

    2007-01-31

    The GLAST LAT Collaboration is one among several experimental groups, covering a wide range of approaches, pursuing the search for the nature of dark matter. The GLAST LAT has the unique ability to find new sources of high energy gamma radiation emanating directly from WIMP annihilations in situ in the universe. Using it's wide band spectral and full sky spatial capabilities, the GLAST LAT can form "images" in high energy gamma-rays of dark matter substructures in the gamma-ray sky. We describe a preliminary feasibility study for indirect detection of Milky Way dark matter satellites using the GLAST LAT.

  13. GENIUS and the Genius TF: A New Observatory for WIMP Dark Matter and Neutrinoless Double Beta Decay

    E-print Network

    H. V. Klapdor-Kleingrothaus; B. Majorovits

    2001-03-07

    The GENIUS proposal is described and some of it's physics potential is outlined. Also in the light of the contradictive results from the DAMA and CDMS experiments the Genius TF, a new experimental setup is proposed. The Genius TF could probe the DAMA evidence region using the WIMP nucleus recoil signal and WIMP annual modulation signature simultaneously. Besides that it can prove the long term feasibility of the detector technique to be implemented into the GENIUS setup and will in this sense be a first step towards the realization of the GENIUS experiment.

  14. GENIUS and the Genius TF A New Observatory for WIMP Dark Matter and Neutrinoless Double Beta Decay

    E-print Network

    Klapdor-Kleingrothaus, Hans Volker

    2001-01-01

    The GENIUS proposal is described and some of it's physics potential is outlined. Also in the light of the contradictive results from the DAMA and CDMS experiments the Genius TF, a new experimental setup is proposed. The Genius TF could probe the DAMA evidence region using the WIMP nucleus recoil signal and WIMP annual modulation signature simultaneously. Besides that it can prove the long term feasibility of the detector technique to be implemented into the GENIUS setup and will in this sense be a first step towards the realization of the GENIUS experiment.

  15. Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two Liter CF$_3$I Bubble Chamber

    SciTech Connect

    Behnke, E.; Behnke, J.; Brice, S.J.; Broemmelsiek, D.; Collar, J.I.; Cooper, P.S.; Crisler, M.; Dahl, C.E.; Fustin, D.; Hall, J.; Hinnefeld, J.H.; /Indiana U., South Bend /Fermilab /Indiana U., South Bend /Fermilab /Indiana U., South Bend /Fermilab

    2010-08-01

    Data from the operation of a bubble chamber filled with 3.5 kg of CF{sub 3}I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1 kg-day, consistent with a neutron background. This observation provides the strongest direct detection constraint to date on WIMP-proton spin-dependent scattering for WIMP masses > 20 GeV/c{sup 2}.

  16. Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two Liter CF$_3$I Bubble Chamber

    E-print Network

    E. Behnke; J. Behnke; S. J. Brice; D. Broemmelsiek; J. I. Collar; P. S. Cooper; M. Crisler; C. E. Dahl; D. Fustin; J. Hall; J. H. Hinnefeld; M. Hu; I. Levine; E. Ramberg; T. Shepherd; A. Sonnenschein; M. Szydagis

    2011-03-07

    Data from the operation of a bubble chamber filled with 3.5 kg of CF$_{3}$I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1 kg-day, consistent with a neutron background. This observation provides the strongest direct detection constraint to date on WIMP-proton spin-dependent scattering for WIMP masses $>20$ GeV/c$^{2}$.

  17. Test battery with the human cell line activation test, direct peptide reactivity assay and DEREK based on a 139 chemical data set for predicting skin sensitizing potential and potency of chemicals.

    PubMed

    Takenouchi, Osamu; Fukui, Shiho; Okamoto, Kenji; Kurotani, Satoru; Imai, Noriyasu; Fujishiro, Miyuki; Kyotani, Daiki; Kato, Yoshinao; Kasahara, Toshihiko; Fujita, Masaharu; Toyoda, Akemi; Sekiya, Daisuke; Watanabe, Shinichi; Seto, Hirokazu; Hirota, Morihiko; Ashikaga, Takao; Miyazawa, Masaaki

    2015-11-01

    To develop a testing strategy incorporating the human cell line activation test (h-CLAT), direct peptide reactivity assay (DPRA) and DEREK, we created an expanded data set of 139 chemicals (102 sensitizers and 37 non-sensitizers) by combining the existing data set of 101 chemicals through the collaborative projects of Japan Cosmetic Industry Association. Of the additional 38 chemicals, 15 chemicals with relatively low water solubility (log Kow > 3.5) were selected to clarify the limitation of testing strategies regarding the lipophilic chemicals. Predictivities of the h-CLAT, DPRA and DEREK, and the combinations thereof were evaluated by comparison to results of the local lymph node assay. When evaluating 139 chemicals using combinations of three methods based on integrated testing strategy (ITS) concept (ITS-based test battery) and a sequential testing strategy (STS) weighing the predictive performance of the h-CLAT and DPRA, overall similar predictivities were found as before on the 101 chemical data set. An analysis of false negative chemicals suggested a major limitation of our strategies was the testing of low water-soluble chemicals. When excluded the negative results for chemicals with log Kow > 3.5, the sensitivity and accuracy of ITS improved to 97% (91 of 94 chemicals) and 89% (114 of 128). Likewise, the sensitivity and accuracy of STS to 98% (92 of 94) and 85% (111 of 129). Moreover, the ITS and STS also showed good correlation with local lymph node assay on three potency classifications, yielding accuracies of 74% (ITS) and 73% (STS). Thus, the inclusion of log Kow in analysis could give both strategies a higher predictive performance. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25820183

  18. High-specificity and high-sensitivity genotoxicity assessment in a human cell line: validation of the GreenScreen HC GADD45a-GFP genotoxicity assay.

    PubMed

    Hastwell, Paul W; Chai, Li-Leng; Roberts, Kevin J; Webster, Thomas W; Harvey, James S; Rees, Robert W; Walmsley, Richard M

    2006-09-01

    The battery of genetic toxicity tests required by most regulatory authorities includes both bacterial and mammalian cell assays and identifies practically all genotoxic carcinogens. However, the relatively high specificity of the Salmonella mutagenicity assay (Ames test) is offset by the low specificity of the established mammalian cell assays, which leads to difficulties in the interpretation of the biological relevance of results. This paper describes a new high-throughput assay that links the regulation of the human GADD45a gene to the production of Green Fluorescent Protein (GFP). A study of 75 well-characterised genotoxic and non-genotoxic compounds with diverse mechanisms of DNA-damage induction (including aneugens) reveals that the assay responds positively to all classes of genotoxic damage with both high specificity and high sensitivity. The current micro-well assay format does not include metabolic activation, but a separate low-throughput protocol demonstrates a successful proof-of-principle for an S9 metabolic activation assay with the model pro-mutagen cyclophosphamide. The test should be of value both as a tool in the selection of candidate compounds for further development, where additional data may be required because of conflicting information from the in vitro test battery, or in product development areas where the use of animals is to be discontinued. As a microplate assay however, it has the qualities of high throughput and low compound use that will facilitate its application in early screening for genotoxic liability. PMID:16781187

  19. Design and synthesis of pH-sensitive polyamino-ester magneto-dendrimers: Surface functional groups effect on viability of human prostate carcinoma cell lines DU145.

    PubMed

    Dayyani, Nahid; Khoee, Sepideh; Ramazani, Ali

    2015-06-15

    Novel pH-sensitive, biocompatible and biodegradable magneto-dendrimers with OH and/or NH2 functional groups based on poly amino-ester were synthesized for delivery of anti-cancer drugs. Magnetite nanoparticles (MNPs) were synthesized by the co-precipitation method and their surfaces were modified by 3-aminopropyl triethoxysilane. The first and second generations of the magneto-dendrimer with hydroxyl end groups were produced by sequential acrylation and Michael addition reactions using the required amounts of acryloyl chloride and diethanolamine, respectively. The dendrimer containing amino functional surface groups up to second generation was synthesized by the same method using the necessary amounts of acryloyl chloride and ethylenediamine. These dendrimers were fully characterized by the Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), dynamic light scattering (DLS) and zeta potential analysis, vibrating-sample magnetometer (VSM), scanning electron microscope (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). In-vitro release profiles of the drug-loaded magnetic nanoparticles and their cytotoxicity assay were investigated at two pHs (7.4 and 5.8). The hydrolytic degradation behavior of magneto-dendrimers was evaluated in PBS buffer. Our research suggests that magneto-dendrimers having amine or hydroxyl functional groups could be considered as the suitable nanocarriers for therapy applications. PMID:26021708

  20. IRE1 inhibition perturbs the unfolded protein response in a pancreatic ?-cell line expressing mutant proinsulin, but does not sensitize the cells to apoptosis

    PubMed Central

    2014-01-01

    Background The Akita mutation (C96Y) in the insulin gene results in early onset diabetes in both humans and mice. Expression of mutant proinsulin (C96Y) causes endoplasmic reticulum (ER) stress in pancreatic ?-cells and consequently the cell activates the unfolded protein response (UPR). Since the proinsulin is terminally misfolded ER stress is irremediable and chronic activation of the UPR eventually activates apoptosis in some cells. Here we analyzed the IRE1-dependent activation of genes in response to misfolded proinsulin production in an inducible mutant proinsulin (C96Y) insulinoma cell line. Results The IRE1 endoribonuclease inhibitors 4?8c and MKC-3946 prevented the splicing of the XBP1 mRNA in response to ER stress caused by mutant proinsulin production. Microarray expression analysis and qPCR validation of select genes revealed that maximal upregulation of many UPR genes in response to mutant proinsulin production required IRE1, although most were still increased above control. Interestingly, neither degradation of misfolded proinsulin via ER-associated degradation (ERAD), nor apoptosis induced by prolonged misfolded proinsulin expression were affected by inhibiting IRE1. Conclusions Although maximal induction of most UPR genes requires IRE1, inhibition of IRE1 does not affect ERAD of misfolded proinsulin or predispose pancreatic ?-cells expressing misfolded proinsulin to chronic ER stress-induced apoptosis. PMID:25011481

  1. Dark Matter Spin-Dependent Limits for WIMP Interactions on 19-F by PICASSO

    E-print Network

    S. Archambault; F. Aubin; M. Auger; E. Behnke; B. Beltran; K. Clark; X. Dai; A. Davour; J. Farine; R. Faust; M. -H. Genest; G. Giroux; R. Gornea; C. Krauss; S. Kumaratunga; I. Lawson; C. Leroy; L. Lessard; C. Levy; I. Levine; R. MacDonald; J. -P. Martin; P. Nadeau; A. Noble; M. -C. Piro; S. Pospisil; T. Shepherd; N. Starinski; I. Stekl; C. Storey; U. Wichoski; V. Zacek

    2009-11-10

    The PICASSO experiment at SNOLAB reports new results for spin-dependent WIMP interactions on $^{19}$F using the superheated droplet technique. A new generation of detectors and new features which enable background discrimination via the rejection of non-particle induced events are described. First results are presented for a subset of two detectors with target masses of $^{19}$F of 65 g and 69 g respectively and a total exposure of 13.75 $\\pm$ 0.48 kgd. No dark matter signal was found and for WIMP masses around 24 GeV/c$^2$ new limits have been obtained on the spin-dependent cross section on $^{19}$F of $\\sigma_F$ = 13.9 pb (90% C.L.) which can be converted into cross section limits on protons and neutrons of $\\sigma_p$ = 0.16 pb and $\\sigma_n$ = 2.60 pb respectively (90% C.L). The obtained limits on protons restrict recent interpretations of the DAMA/LIBRA annual modulations in terms of spin-dependent interactions.

  2. Consequences of DM/antiDM oscillations for asymmetric WIMP dark matter

    SciTech Connect

    Cirelli, Marco; Panci, Paolo; Servant, Géraldine; Zaharijas, Gabrijela E-mail: panci@cp3-origins.net E-mail: gzaharij@ictp.it

    2012-03-01

    Assuming the existence of a primordial asymmetry in the dark sector, a scenario usually dubbed Asymmetric Dark Matter (aDM), we study the effect of oscillations between dark matter and its antiparticle on the re-equilibration of the initial asymmetry before freeze-out, which enable efficient annihilations to recouple. We calculate the evolution of the DM relic abundance and show how oscillations re-open the parameter space of aDM models, in particular in the direction of allowing large (WIMP-scale) DM masses. A typical WIMP with a mass at the EW scale ( ? 100 GeV – 1 TeV) presenting a primordial asymmetry of the same order as the baryon asymmetry naturally gets the correct relic abundance if the DM-number-violating ?(DM) = 2 mass term is in the ? meV range. The re-establishment of annihilations implies that constraints from the accumulation of aDM in astrophysical bodies are evaded. On the other hand, the ordinary bounds from BBN, CMB and indirect detection signals on annihilating DM have to be considered.

  3. Microwave assisted saponification (MAS) followed by on-line liquid chromatography (LC)-gas chromatography (GC) for high-throughput and high-sensitivity determination of mineral oil in different cereal-based foodstuffs.

    PubMed

    Moret, Sabrina; Scolaro, Marianna; Barp, Laura; Purcaro, Giorgia; Conte, Lanfranco S

    2016-04-01

    A high throughput, high-sensitivity procedure, involving simultaneous microwave-assisted extraction (MAS) and unsaponifiable extraction, followed by on-line liquid chromatography (LC)-gas chromatography (GC), has been optimised for rapid and efficient extraction and analytical determination of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) in cereal-based products of different composition. MAS has the advantage of eliminating fat before LC-GC analysis, allowing an increase in the amount of sample extract injected, and hence in sensitivity. The proposed method gave practically quantitative recoveries and good repeatability. Among the different cereal-based products analysed (dry semolina and egg pasta, bread, biscuits, and cakes), egg pasta packed in direct contact with recycled paperboard had on average the highest total MOSH level (15.9mgkg(-1)), followed by cakes (10.4mgkg(-1)) and bread (7.5mgkg(-1)). About 50% of the pasta and bread samples and 20% of the biscuits and cake samples had detectable MOAH amounts. The highest concentrations were found in an egg pasta in direct contact with recycled paperboard (3.6mgkg(-1)) and in a milk bread (3.6mgkg(-1)). PMID:26593464

  4. Transfection of a human glioblastoma cell line with liver-type glutaminase (LGA) down-regulates the expression of DNA-repair gene MGMT and sensitizes the cells to alkylating agents.

    PubMed

    Szeliga, Monika; Zgrzywa, Agata; Obara-Michlewska, Marta; Albrecht, Jan

    2012-11-01

    O(6)-methylguanine-DNA methyltransferase (MGMT) is a DNA-repair protein promoting resistance of tumor cells to alkylating chemotherapeutic agents. Glioma cells are particularly resistant to this class of drugs which include temozolomide (TMZ) and carmustine (BCNU). A previous study using the RNA microarray technique showed that decrease of MGMT mRNA stands out among the alterations in gene expression caused by the cell growth-depressing transfection of a T98G glioma cell line with liver-type glutaminase (LGA) [Szeliga et al. (2009) Glia, 57, 1014]. Here, we show that stably LGA-transfected cells (TLGA) exhibit decreased MGMT protein expression and activity as compared with non-transfected or mock transfected cells (controls). However, the decrease of expression occurs in the absence of changes in the methylation of the promoter region, indicating that LGA circumvents, by an as yet unknown route, the most common mechanism of MGMT silencing. TLGA turned out to be significantly more sensitive to treatment with 100-1000 ?M of TMZ and BCNU in the acute cell growth inhibition assay (MTT). In the clonogenic survival assay, TLGA cells displayed increased sensitivity even to 10 ?M TMZ and BCNU. Our results indicate that enrichment with LGA, in addition to inhibiting glioma growth, may facilitate chemotherapeutic intervention. PMID:22888977

  5. Large-scale nuclear structure calculations for spin-dependent WIMP scattering with chiral effective field theory currents

    E-print Network

    P. Klos; J. Menéndez; D. Gazit; A. Schwenk

    2015-01-23

    We perform state-of-the-art large-scale shell-model calculations of the structure factors for elastic spin-dependent WIMP scattering off 129,131Xe, 127I, 73Ge, 19F, 23Na, 27Al, and 29Si. This comprehensive survey covers the non-zero-spin nuclei relevant to direct dark matter detection. We include a pedagogical presentation of the formalism necessary to describe elastic and inelastic WIMP-nucleus scattering. The valence spaces and nuclear interactions employed have been previously used in nuclear structure calculations for these mass regions and yield a good spectroscopic description of these isotopes. We use spin-dependent WIMP-nucleus currents based on chiral effective field theory (EFT) at the one-body level and including the leading long-range two-body currents due to pion exchange, which are predicted in chiral EFT. Results for all structure factors are provided with theoretical error bands due to the nuclear uncertainties of WIMP currents in nuclei.

  6. Effects of Residue Background Events in Direct Dark Matter Detection Experiments on the Estimation of the Spin-Independent WIMP-Nucleon Coupling

    E-print Network

    Chung-Lin Shan

    2011-08-16

    In our work on the development of a model-independent data analysis method for estimating the spin-independent (SI) scalar coupling of Weakly Interacting Massive Particles (WIMPs) on nucleons by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the estimation of the SI WIMP-nucleon coupling, the maximal acceptable fraction of residue background events in the analyzed data set of O(50) total events is ~ 10% - 20%. For a WIMP mass of 100 GeV and 20% residue background events, the systematic deviation of the reconstructed SI WIMP coupling (with a reconstructed WIMP mass) would in principle be ~ +13% with a statistical uncertainty of ~ ^{+21%}_{-14%} (~ -3.3%^{+18%}_{-13%} for background-free data sets).

  7. Pre-launch Estimates for GLAST Sensitivity to Dark Matter Annihilation Signals

    SciTech Connect

    Baltz, E.A.; Berenji, B.; Bertone, G.; Bergstrom, L.; Bloom, E.; Bringmann, T.; Chiang, J.; Cohen-Tanugi, J.; Conrad, J.; Edmonds, Y.; Edsjo, J.; Godfrey, G.; Hughes, R.E.; Johnson, R.P.; Lionetto, A.; Moiseev, A.A.; Morselli, A.; Moskalenko, I.V.; Nuss, E.; Ormes, J.F.; Rando, R.; /INFN, Padua /Ohio State U. /Stockholm U. /Ohio State U. /Garching, Max Planck Inst., MPE /SLAC /KIPAC, Menlo Park /Ohio State U.

    2009-05-15

    We investigate the sensitivity of the Gamma-ray Large Area Space Telescope (GLAST) to indirectly detect weakly interacting massive particles (WIMPs) through the {gamma}-ray signal that their pair annihilation produces. WIMPs are among the favorite candidates to explain the compelling evidence that about 80% of the mass in the Universe is non-baryonic dark matter (DM). They are serendipitously motivated by various extensions of the standard model of particle physics such as Supersymmetry and Universal Extra Dimensions (UED). With its unprecedented sensitivity and its very large energy range (20 MeV to more than 300 GeV) the main instrument on board the GLAST satellite, the Large Area Telescope (LAT), will open a new window of discovery. As our estimates show, the LAT will be able to detect an indirect DM signature for a large class of WIMP models given a cuspy profile for the DM distribution. Using the current state of the art Monte Carlo and event reconstruction software developed within the LAT collaboration, we present preliminary sensitivity studies for several possible sources inside and outside the Galaxy. We also discuss the potential of the LAT to detect UED via the electron/positron channel. Diffuse background modeling and other background issues that will be important in setting limits or seeing a signal are presented.

  8. Theoretical direct WIMP detection rates for transitions to the first excited state in 83Kr

    NASA Astrophysics Data System (ADS)

    Vergados, J. D.; Avignone, F. T.; Pirinen, P.; Srivastava, P. C.; Kortelainen, M.; Suhonen, J.

    2015-07-01

    The direct detection of dark matter constituents, in particular the weakly interacting massive particles (WIMPs), is central to particle physics and cosmology. In this paper we study transitions to the excited states, possible in some nuclei, which have sufficiently low lying excited states. Examples considered previously were the first excited states of 127I and 129Xe. We examine here 83Kr, which offers some kinematical advantages and is a possible target. We estimate appreciable rates for the inelastic scattering mediated by the spin cross sections, with an inelastic event rate of 4.4 ×10-4 kg-1 d-1 . So, the extra signature of the gamma ray following the de-excitation of these states can, in principle, be exploited experimentally. A brief discussion of the experimental feasibility is given.

  9. WIMPs in a 3-3-1 model with heavy sterile neutrinos

    SciTech Connect

    Mizukoshi, J. K.; Pires, C.A. de S; Queiroz, F. S.; Rodrigues da Silva, P. S.

    2011-03-15

    In this work we build a gauge model based on the SU(3){sub c} x SU(3){sub L} x U(1){sub N} symmetry with heavy neutrinos and show that we can have two weakly interacting cold dark matter candidates in its spectrum. This is achieved by noticing that a global U(1) symmetry can be imposed on the model in such a way that the stability of the dark matter is guaranteed. We obtain their relic abundance and analyze their compatibility with recent direct detection experiments, also exploring the possibility of explaining the two events reported by CDMSII. An interesting outcome of this 3-3-1 model, concerning direct detection of these WIMPs, is a strong bound on the symmetry breaking scale, which imposes it to be above 3 TeV.

  10. CMB constraints on WIMP annihilation: Energy absorption during the recombination epoch

    SciTech Connect

    Slatyer, Tracy R.; Padmanabhan, Nikhil; Finkbeiner, Douglas P.

    2009-08-15

    We compute in detail the rate at which energy injected by dark matter (DM) annihilation heats and ionizes the photon-baryon plasma at z{approx}1000, and provide accurate fitting functions over the relevant redshift range for a broad array of annihilation channels and DM masses. The resulting perturbations to the ionization history can be constrained by measurements of the CMB temperature and polarization angular power spectra. We show that models which fit recently measured excesses in 10-1000 GeV electron and positron cosmic rays are already close to the 95% confidence limits from WMAP. The recently launched Planck satellite will be capable of ruling out a wide range of DM explanations for these excesses. In models of dark matter with Sommerfeld-enhanced annihilation, where <{sigma}v> rises with decreasing WIMP velocity until some saturation point, the WMAP5 constraints imply that the enhancement must be close to saturation in the neighborhood of the Earth.

  11. Dark matter sensitivities of the Majorana Demonstrator

    NASA Astrophysics Data System (ADS)

    Giovanetti, G. K.; Aguayo, E.; Avignone, F. T., Iii; Back, H. O.; Barabash, A. S.; Beene, J. R.; Bergevin, M.; Bertrand, F. E.; Boswell, M.; Brudanin, V.; Busch, M.; Chan, Y.-D.; Christofferson, C. D.; Collar, J. I.; Combs, D. C.; Cooper, R. J.; Detwiler, J. A.; Doe, P. J.; Efremenko, Yu; Egorov, V.; Ejiri, H.; Elliott, S. R.; Esterline, J.; Fast, J. E.; Fields, N.; Finnerty, P.; Fraenkle, F. M.; Gehman, V. M.; Green, M. P.; Guiseppe, V. E.; Gusey, K.; Hallin, A. L.; Hazama, R.; Henning, R.; Hoppe, E. W.; Horton, M.; Howard, S.; Howe, M. A.; Johnson, R. A.; Keeter, K. J.; Keller, C.; Kidd, M. F.; Knecht, A.; Kochetov, O.; Konovalov, S. I.; Kouzes, R. T.; LaFerriere, B. D.; LaRoque, B. H.; Leon, J.; Leviner, L. E.; Loach, J. C.; MacMullin, S.; Marino, M. G.; Martin, R. D.; Mei, D.-M.; Merriman, J. H.; Miller, M. L.; Mizouni, L.; Nomachi, M.; Orrell, J. L.; Overman, N. R.; Phillips, D. G., Ii; Poon, A. W. P.; Perumpilly, G.; Prior, G.; Radford, D. C.; Rielage, K.; Robertson, R. G. H.; Ronquest, M. C.; Schubert, A. G.; Shima, T.; Shirchenko, M.; Snavely, K. J.; Steele, D.; Strain, J.; Thomas, K.; Timkin, V.; Tornow, W.; Vanyushin, I.; Varner, R. L.; Vetter, K.; Vorren, K.; Wilkerson, J. F.; Yakushev, E.; Young, A. R.; Yu, C.-H.; Yumatov, V.; Zhang, C.

    2012-07-01

    The Majorana Demonstrator is an array of natural and enriched high purity germanium detectors that will search for the neutrinoless double-beta decay of Germanium-76 and perform a search for weakly interacting massive particles with masses below 10 GeV. To reach the background rate goal in the neutrinoless double-beta decay region of interest of 4 counts/keV/t/y, the DEMONSTRATOR will utilize a number of background reduction strategies, including a time-correlated event cut for 68Ge that requires a sub-keV energy threshold. This low energy threshold allows the DEMONSTRATOR to extend its physics reach to include a search for light WIMPs. We will discuss the detector systems and data analysis techniques required to achieve sub-keV thresholds as well as present the projected dark matter sensitivities of the Majorana Demonstrator.

  12. Upper bounds on signals due to WIMP self-annihilation: Comments on the case of the synchrotron radiation from the galactic center and the WMAP haze

    SciTech Connect

    Bottino, A.; Donato, F.; Fornengo, N.; Scopel, S.

    2008-06-15

    Two recent papers reconsider the possibility that the WMAP haze is due to the synchrotron emission originated by neutralino self-annihilation; also upper bounds on the neutralino self-annihilation cross section are suggested. We show that for thermal weakly interacting massive particles (WIMPs) in a standard cosmological model, when the galactic WIMP density is duly rescaled for subdominant WIMPs, the upper bound applicable generically to any signal due to self-conjugate WIMPs is more stringent than the ones obtained from analysis of the WMAP haze. We also argue that an experimental upper bound, which can compete with our generic upper limit, can rather be derived from measurements of cosmic antiproton fluxes. Finally, we comment on the possible impact of our generic upper bound on the interpretation of the WMAP haze in terms of thermal neutralinos in a standard cosmological scheme.

  13. Food Sensitivities

    PubMed Central

    Cutler, Paul

    1984-01-01

    Food sensitivities are a common but frequently unrecognized cause of chronic symptomatology in patients with known allergies. Food sensitivities often are not detected by skin testing. This article discusses the controversy surrounding the treatment of food sensitivities; the provocative sublingual and intradermal tests for sensitivities, and the importance of eliciting complete past and family histories from the allergic patient. Because patients with symptoms of food sensitivity are likely to visit their family doctor first, he should be the first to detect and treat them. Usually patients with a food sensitivity obtain relief from symptoms when the offending food(s) are excluded from their diet. PMID:21283500

  14. Limits on spin-independent couplings of WIMP dark matter with a p-type point-contact germanium detector.

    PubMed

    Li, H B; Liao, H Y; Lin, S T; Liu, S K; Singh, L; Singh, M K; Soma, A K; Wong, H T; Wu, Y C; Zhao, W; Asryan, G; Chuang, Y C; Deniz, M; Fang, J M; Hsu, C L; Huang, T R; Kiran Kumar, G; Lee, S C; Li, J; Li, J M; Li, Y J; Li, Y L; Lin, C W; Lin, F K; Liu, Y F; Ma, H; Ruan, X C; Shen, Y T; Singh, V; Tang, C J; Tseng, C H; Xu, Y; Yang, S W; Yu, C X; Yue, Q; Zeng, Z; Zeyrek, M; Zhou, Z Y

    2013-06-28

    We report new limits on a spin-independent weakly interacting massive particle (WIMP)-nucleon interaction cross section using 39.5 kg days of data taken with a p-type point-contact germanium detector of 840 g fiducial mass at the Kuo-Sheng Reactor Neutrino Laboratory. Crucial to this study is the understanding of the selection procedures and, in particular, the bulk-surface events differentiation at the sub-keV range. The signal-retaining and background-rejecting efficiencies were measured with calibration gamma sources and a novel n-type point-contact germanium detector. Part of the parameter space in the cross section versus WIMP-mass implied by various experiments is probed and excluded. PMID:23848861

  15. Limits on spin-independent couplings of WIMP dark matter with a p-type point-contact germanium detector

    E-print Network

    TEXONO Collaboration

    2013-07-09

    We report new limits on spin-independent WIMP-nucleon interaction cross-section using 39.5 kg-days of data taken with a p-type point-contact germanium detector of 840 g fiducial mass at the Kuo-Sheng Reactor Neutrino Laboratory. Crucial to this study is the understanding of the selection procedures and, in particular, the bulk-surface events differentiation at the sub-keV range. The signal-retaining and background-rejecting efficiencies were measured with calibration gamma sources and a novel n-type point-contact germanium detector. Part of the parameter space in cross-section versus WIMP-mass implied by various experiments is probed and excluded.

  16. Discovery of underground argon with low level of radioactive 39Ar and possible applications to WIMP dark matter detectors

    E-print Network

    C. Galbiati; R. Purtschert

    2007-12-03

    We report on the first measurement of 39Ar in argon from underground natural gas reservoirs. The gas stored in the US National Helium Reserve was found to contain a low level of 39Ar. The ratio of 39Ar to stable argon was found to be argon (39Ar/Ar=8x10-16). The total quantity of argon currently stored in the National Helium Reserve is estimated at 1000 tons. 39Ar represents one of the most important backgrounds in argon detectors for WIMP dark matter searches. The findings reported demonstrate the possibility of constructing large multi-ton argon detectors with low radioactivity suitable for WIMP dark matter searches.

  17. Adaptive Sensitivity 1 Adaptive Sensitivity

    E-print Network

    Ginosar, Ran

    1 Adaptive Sensitivity 1 Adaptive Sensitivity Ran Ginosar Introduction Solid state (and other Cut-Off Sensitive Region Typically, 100:1 , the human eye has a much wider dynamic range, in excess of 108 :1, but the response is non linear. Rather

  18. Dark matter formation at Schwarz scales: primordial fog particles and WIMP superhalos

    E-print Network

    Carl H. Gibson

    1999-04-21

    Dark matter appears in two forms as a consequence of the fluid mechanics of self-gravitational condensation. Condensation occurs primarily on non-acoustic nuclei rather than on the acoustic nuclei of the Jeans (1902) criterion, leading to a very different scenario for structure formation. Viscous forces at 10^12 s (30,000 y) after the big bang permit decelerations of 10^47 kg protosupercluster plasma masses, and 10^42 kg protogalaxy masses at 10^13 s (300,000 y). Then gas formed, and all the baryonic universe became a "primordial fog" of 10^23 kg particles at the viscous Schwarz scale: 100% dark matter. Some of these H-He objects have collected to form stars, but most persist as dark dwarfs in galaxy halos. They manifest themselves in quasar microlensing observations as "rogue planets", Schild (1996), "dark galaxies", Hawkins (1996), and as comets "brought out of cold storage", O'Dell and Handron (1996). Non-baryonic WIMP fluids are superviscous, with large viscous Schwarz scales, and condense slowly to form most of the dark matter of galaxy superclusterhalos and clusterhalos.

  19. Context Sensitive Modeling of Cancer Drug Sensitivity

    PubMed Central

    Chen, Bo-Juen; Litvin, Oren; Ungar, Lyle; Pe’er, Dana

    2015-01-01

    Recent screening of drug sensitivity in large panels of cancer cell lines provides a valuable resource towards developing algorithms that predict drug response. Since more samples provide increased statistical power, most approaches to prediction of drug sensitivity pool multiple cancer types together without distinction. However, pan-cancer results can be misleading due to the confounding effects of tissues or cancer subtypes. On the other hand, independent analysis for each cancer-type is hampered by small sample size. To balance this trade-off, we present CHER (Contextual Heterogeneity Enabled Regression), an algorithm that builds predictive models for drug sensitivity by selecting predictive genomic features and deciding which ones should—and should not—be shared across different cancers, tissues and drugs. CHER provides significantly more accurate models of drug sensitivity than comparable elastic-net-based models. Moreover, CHER provides better insight into the underlying biological processes by finding a sparse set of shared and type-specific genomic features. PMID:26274927

  20. Effects of residue background events in direct dark matter detection experiments on the reconstruction of the velocity distribution function of halo WIMPs

    SciTech Connect

    Shan, Chung-Lin

    2010-06-01

    In our earlier work on the development of a model-independent data analysis method for reconstructing the (moments of the) time-averaged one-dimensional velocity distribution function of Weakly Interacting Massive Particles (WIMPs) by using measured recoil energies from direct Dark Matter detection experiments directly, it was assumed that the analyzed data sets are background-free, i.e., all events are WIMP signals. In this article, as a more realistic study, we take into account a fraction of possible residue background events, which pass all discrimination criteria and then mix with other real WIMP-induced events in our data sets. Our simulations show that, for the reconstruction of the one-dimensional WIMP velocity distribution, the maximal acceptable fraction of residue background events in the analyzed data set(s) of O(500) total events is ? 10%–20%. For a WIMP mass of 50 GeV with a negligible uncertainty and 20% residue background events, the deviation of the reconstructed velocity distribution would in principle be ? 7.5% with a statistical uncertainty of ? 18% ( ? 19% for a background-free data set)

  1. Measure Lines

    ERIC Educational Resources Information Center

    Crissman, Sally

    2011-01-01

    One tool for enhancing students' work with data in the science classroom is the measure line. As a coteacher and curriculum developer for The Inquiry Project, the author has seen how measure lines--a number line in which the numbers refer to units of measure--help students not only represent data but also analyze it in ways that generate…

  2. Gluten Sensitivity

    MedlinePLUS

    ... Disease Celiac Disease, Non-Celiac Gluten Sensitivity or Wheat Allergy: What is the Difference? Could Gluten be ... suspicious. To diagnose GS, both celiac disease and wheat allergy should be ruled out. Antibody testing and ...

  3. Gluten Sensitivity

    MedlinePLUS

    Gluten is a protein found in wheat, rye, and barley. It is found mainly in foods but ... products like medicines, vitamins, and supplements. People with gluten sensitivity have problems with gluten. It is different ...

  4. Measurement of the quenching and channeling effects in a CsI crystal used for a WIMP search

    NASA Astrophysics Data System (ADS)

    Lee, J. H.; Kim, G. B.; Seong, I. S.; Kim, B. H.; Kim, J. H.; Li, J.; Park, J. W.; Lee, J. K.; Kim, K. W.; Bhang, H.; Kim, S. C.; Choi, Seonho; Choi, J. H.; Joo, H. W.; Lee, S. J.; Olsen, S. L.; Myung, S. S.; Kim, S. K.; Kim, Y. D.; Kang, W. G.; So, J. H.; Kim, H. J.; Lee, H. S.; Hahn, I. S.; Leonard, D. S.; Li, J.; Li, Y. J.; Yue, Q.; Li, X. R.

    2015-05-01

    We have studied channeling effects in a cesium iodide (CsI) crystal that is similar in composition to the ones being used in a search for Weakly Interacting Massive Particles (WIMPs) dark matter candidates, and measured its energy-dependent quenching factor, the relative scintillation yield for electron and nuclear recoils. The experimental results are reproduced with a GEANT4 simulation that includes a model of the scintillation efficiency as a function of electronic stopping power. We present the measured and simulated quenching factors and the estimated effects of channeling.

  5. Measurement of the quenching and channeling effects in a CsI crystal used for a WIMP search

    E-print Network

    J. H. Lee; G. B. Kim; I. S. Seong; B. H. Kim; J. H. Kim; J. Li; J. W. Park; J. K. Lee; K. W. Kim; H. Bhang; S. C. Kim; Seonho Choi; J. H. Choi; H. W. Joo; S. J. Lee; S. L. Olsen; S. S. Myung; S. K. Kim; Y. D. Kim; W. G. Kang; J. H. So; H. J. Kim; H. S. Lee; I. S. Hahn; D. S. Leonard; J. Li; Y. J. Li; Q. Yue; X. R. Li

    2015-02-12

    We have studied channeling effects in a Cesium Iodide (CsI) crystal that is similar in composition to the ones being used in a search for Weakly Interacting Massive Particles (WIMPs) dark matter candidates, and measured its energy-dependent quenching factor, the relative scintillation yield for electron and nuclear recoils. The experimental results are reproduced with a GEANT4 simulation that includes a model of the scintillation efficiency as a function of electronic stopping power. We present the measured and simulated quenching factors and the estimated effects of channeling.

  6. Measurement of the quenching and channeling effects in a CsI crystal used for a WIMP search

    E-print Network

    Lee, J H; Seong, I S; Kim, B H; Kim, J H; Li, J; Park, J W; Lee, J K; Kim, K W; Bhang, H; Kim, S C; Choi, Seonho; Choi, J H; Joo, H W; Lee, S J; Olsen, S L; Myung, S S; Kim, S K; Kim, Y D; Kang, W G; So, J H; Kim, H J; Lee, H S; Hahn, I S; Leonard, D S; Li, Y J; Yue, Q; Li, X R

    2015-01-01

    We have studied channeling effects in a Cesium Iodide (CsI) crystal that is similar in composition to the ones being used in a search for Weakly Interacting Massive Particles (WIMPs) dark matter candidates, and measured its energy-dependent quenching factor, the relative scintillation yield for electron and nuclear recoils. The experimental results are reproduced with a GEANT4 simulation that includes a model of the scintillation efficiency as a function of electronic stopping power. We present the measured and simulated quenching factors and the estimated effects of channeling.

  7. Exclusion limits on the WIMP-nucleon cross section from the first run of the Cryogenic Dark Matter Search in the Soudan Underground Laboratory

    SciTech Connect

    Armel-Funkhouser, M.S.; Attisha, M.J.; Bailey, C.N.; Baudis, L.; Bauer, Daniel A.; Brink, P.L.; Bunker, R.; Cabrera, B.; Caldwell, D.O.; Chang, C.L.; Crisler, M.B.; Cushman, P.; Daal, M.; Dixon, R.; Dragowsky, M.R.; Driscoll, D.D.; Duong, L.; Ferril, R.; Filippini, J.; Gaitskell, R.J.; Hennings-Yeomans, R.; /Case Western Reserve U. /Fermilab /Case Western Reserve U. /Denver U. /Case Western Reserve U. /UC, Berkeley /UC, Santa Barbara /UC, Berkeley /NIST, Boulder /UC, Berkeley /UC, Santa Barbara /Case Western Reserve U. /Case Western Reserve U. /UC, Berkeley /Fermilab /UC, Berkeley /Minnesota U. /UC, Berkeley /LBL, Berkeley /Case Western Reserve U. /UC, Berkeley /LBL, Berkeley /UC, Santa Barbara /Case Western Reserve U. /UC, Berkeley /Case Western Reserve U. /Case Western Reserve U. /Case Western Reserve U. /UC, Santa Barbara /Case Western Reserve U.

    2005-07-01

    The Cryogenic Dark Matter Search (CDMS-II) employs low-temperature Ge and Si detectors to seek Weakly Interacting Massive Particles (WIMPs) via their elastic scattering interactions with nuclei. Simultaneous measurements of both ionization and phonon energy provide discrimination against interactions of background particles. For recoil energies above 10 keV, events due to background photons are rejected with > 99.99% efficiency. Electromagnetic events very near the detector surface can mimic nuclear recoils because of reduced charge collection, but these surface events are rejected with > 96% efficiency by using additional information from the phonon pulse shape. Efficient use of active and passive shielding, combined with the 2090 m.w.e. overburden at the experimental site in the Soudan mine, makes the background from neutrons negligible for this first exposure. All cuts are determined in a blind manner from in situ calibrations with external radioactive sources without any prior knowledge of the event distribution in the signal region. Resulting efficiencies are known to {approx}10%. A single event with a recoil of 64 keV passes all of the cuts and is consistent with the expected misidentification rate of surface-electron recoils. Under the assumptions for a standard dark matter halo, these data exclude previously unexplored parameter space for both spin-independent and spin-dependent WIMP-nucleon elastic scattering. The resulting limit on the spin-independent WIMP-nucleon elastic-scattering cross-section has a minimum of 4 x 10{sup -43} cm{sup 2} at a WIMP mass of 60 GeV c{sup -2}. The minimum of the limit for the spin-dependent WIMP-neutron elastic-scattering cross-section is 2 x 10{sup -37} cm{sup 2} at a WIMP mass of 50 GeV c{sup -2}.

  8. Improved Limits on Spin-Dependent WIMP-Proton Interactions from a Two Liter CF{sub 3}I Bubble Chamber

    SciTech Connect

    Behnke, E.; Behnke, J.; Hinnefeld, J. H.; Levine, I.; Shepherd, T.; Brice, S. J.; Broemmelsiek, D.; Cooper, P. S.; Crisler, M.; Hall, J.; Hu, M.; Ramberg, E.; Sonnenschein, A.; Collar, J. I.; Dahl, C. E.; Fustin, D.; Szydagis, M.

    2011-01-14

    Data from the operation of a bubble chamber filled with 3.5 kg of CF{sub 3}I in a shallow underground site are reported. An analysis of ultrasound signals accompanying bubble nucleations confirms that alpha decays generate a significantly louder acoustic emission than single nuclear recoils, leading to an efficient background discrimination. Three dark matter candidate events were observed during an effective exposure of 28.1 kg day, consistent with a neutron background. This observation provides strong direct detection constraints on weakly interacting massive particle (WIMP)-proton spin-dependent scattering for WIMP masses >20 GeV/c{sup 2}.

  9. Circumstellar radio molecular lines

    NASA Technical Reports Server (NTRS)

    NGUYEN-QUANG-RIEU

    1987-01-01

    Radio molecular lines appear to be useful probes into the stellar environment. Silicon oxide masers provide information on the physical conditions in the immediate vicinity of the stellar photosphere. Valuable information on the physics operating in the envelope of IRC + 10216 was recently obtained by high sensitivity observations and detailed theoretical analyses. Infrared speckle interferometry in the molecular lines and in the continuum is helpful in the investigation of the inner region of the envelope. These techniques are discussed in terms of late-type star mass loss.

  10. A Dose-Response Modeling Approach Shows That Effects From Mixture Exposure to the Skin Sensitizers Isoeugenol and Cinnamal Are in Line With Dose Addition and Not With Synergism.

    PubMed

    Kienhuis, Anne S; Slob, Wout; Gremmer, Eric R; Vermeulen, Jolanda P; Ezendam, Janine

    2015-09-01

    Currently, hazard characterization of skin sensitizers is based on data obtained from studies examining single chemicals. Many consumer products, however, contain mixtures of sensitizers that might interact in such a way that the response induced by a substance is higher than predicted in the hazard assessment. To assess interaction of skin sensitizers in a mixture, a dose-response modeling approach is applied. With this approach, it is possible to assess whether or not responses from mixtures of sensitizers can be predicted from the dose-response information obtained from individual chemicals using dose addition. We selected the skin sensitizers isoeugenol and cinnamal, frequently occurring together in consumer products, to be examined in an adjusted local lymph node assay (LLNA). Cell number and cytokine production (IL-10 and IFN-?) of the auricular lymph nodes were measured as hallmarks of the skin sensitization response. We found that dose addition for these 2 skin sensitizers closely predicted the effects from mixtures of both chemicals across the broad dose range tested. Hence, isoeugenol and cinnamal show no synergistic effects in the LLNA. Therefore, hazard assessment and risk assessment of these substances can be performed without taking into account mixture exposure. PMID:26048650

  11. Constraints on WIMP annihilation for contracted dark matter in the inner Galaxy with the Fermi-LAT

    SciTech Connect

    Gómez-Vargas, Germán A.; Huh, Ji-Haeng; Peiró, Miguel; Cerdeño, David G.; Muñoz, Carlos; Sánchez-Conde, Miguel A.; Prada, Francisco; Morselli, Aldo; Klypin, Anatoly; Mambrini, Yann E-mail: masc@stanford.edu E-mail: miguel.peiro@uam.es E-mail: aldo.morselli@roma2.infn.it E-mail: davidg.cerdeno@uam.es E-mail: carlos.munnoz@uam.es

    2013-10-01

    We derive constraints on parameters of generic dark matter candidates by comparing theoretical predictions with the gamma-ray emission observed by the Fermi-LAT from the region around the Galactic Center. Our analysis is conservative since it simply requires that the expected dark matter signal does not exceed the observed emission. The constraints obtained in the likely case that the collapse of baryons to the Galactic Center is accompanied by the contraction of the dark matter are strong. In particular, we find that for b b-bar and ?{sup +}?{sup ?} or W{sup +}W{sup ?} dark matter annihilation channels, the upper limits on the annihilation cross section imply that the thermal cross section is excluded for a Weakly Interacting Massive Particle (WIMP) mass smaller than about 700 and 500 GeV, respectively. For the ?{sup +}?{sup ?} channel, where the effect of the inverse Compton scattering is important, depending on models of the Galactic magnetic field the exclusion of the thermal cross-section is for a WIMP mass smaller than about 150 to 400 GeV. The upper limits on the annihilation cross section of dark matter particles obtained are two orders of magnitude stronger than without contraction. In the latter case our results are compatible with the upper limits from the Galactic halo analysis reported by the Fermi-LAT collaboration for the case in which the same conservative approach without modeling of the astrophysical background is employed.

  12. Constraints on WIMP and Sommerfeld-enhanced dark matter annihilation from HESS observations of the galactic center

    SciTech Connect

    Abazajian, Kevork N.; Harding, J. Patrick E-mail: hard0923@umd.edu

    2012-01-01

    We examine the constraints on models of weakly interacting massive particle (WIMP) dark matter from the recent observations of the Galactic Center by the High Energy Spectroscopic System (HESS) telescope. We analyze canonical WIMP annihilation into Standard Model particle final states, including b b-bar , t t-bar and W{sup +}W{sup ?}. The constraints on annihilation into b b-bar is within an order of magnitude of the thermal cross section at ? 3 TeV, while the ?{sup +}?{sup ?} channel is within a factor of ? 2 of thermal. We also study constraints on Sommerfeld-enhanced dark matter annihilation models, and find that the gamma-ray observational constraints here rule out all of the parameter space consistent with dark matter annihilation interpretations of PAMELA and the Fermi-LAT e{sup +}e{sup ?} spectrum, in specific classes of models, and strongly constrains these interpretations in other classes. The gamma-ray constraints we find are more constraining on these models, in many cases, than current relic density, cosmic microwave background, halo shape and naturalness constraints.

  13. Study of light detection and sensitivity for a ton-scale liquid xenon dark matter detector

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Lin, Q.; Xiao, X.; Ni, K.

    2013-06-01

    Ton-scale liquid xenon detectors operated in two-phase mode are proposed and being constructed recently to explore the favored parameter space for the Weakly Interacting Massive Particles (WIMPs) dark matter. To achieve a better light collection efficiency while limiting the number of electronics channels compared to the previous generation detectors, large-size photo-multiplier tubes (PMTs) such as the 3-inch-diameter R11410 from Hamamatsu are suggested to replace the 1-inch-square R8520 PMTs. In a two-phase xenon dark matter detector, two PMT arrays on the top and bottom are usually used. In this study, we compare the performance of two different ton-scale liquid xenon detector configurations with the same number of either R11410 (config.1) or R8520 (config.2) for the top PMT array, while both using R11410 PMTs for the bottom array. The self-shielding of liquid xenon suppresses the background from the PMTs and the dominant background is from the pp solar neutrinos in the central fiducial volume. The light collection efficiency for the primary scintillation light is largely affected by the xenon purity and the reflectivity of the reflectors. In the optimistic situation with a 10 m light absorption length and a 95% reflectivity, the light collection efficiency is 43%(34%) for config.1(config.2). In the conservative situation with a 2.5 m light absorption length and a 85% reflectivity, the value is only 18%(13%) for config.1(config.2). The difference between the two configurations is due to the larger PMT coverage on the top for config.1. The slightly different position resolutions for the two configurations have a negligible effect on the sensitivity. Based on the above considerations, we estimate the sensitivity reach of the two detector configurations. Both configurations can reach a sensitivity of 2 ~ 3 × 10-47cm2 for spin-independent WIMP-nucleon cross section for 100 GeV/c2 WIMPs after two live-years of operation. The one with R8520 PMTs for the top PMT array is more cost-effective, while the one with R11410 PMTs on the top has a factor of two better sensitivity for light WIMPs at 10 GeV/c2.

  14. Development of bubble chambers with enhanced stability and sensitivity to low-energy nuclear recoils

    NASA Astrophysics Data System (ADS)

    Bolte, W. J.; Collar, J. I.; Crisler, M.; Hall, J.; Holmgren, D.; Nakazawa, D.; Odom, B.; O'Sullivan, K.; Plunkett, R.; Ramberg, E.; Raskin, A.; Sonnenschein, A.; Vieira, J. D.

    2007-07-01

    The viability of using Bubble Chambers as dark matter particle detectors is considered. Techniques leading to the enhanced chamber stability needed for this new application are described in detail. Prototype trials show that sensitivity to the low-energy nuclear recoils induced by Weakly Interacting Massive Particles (WIMP) is possible in conditions of extreme insensitivity to minimum ionizing backgrounds. An understanding of detector response is demonstrated using existing theoretical models. We briefly comment on the prospects for detection of supersymmetric dark matter with large CF3I chambers.

  15. Durham, July 14 2009 Aldo Morselli, INFN Roma Tor Vergata 15th Patras Workshop on Axions, WIMPs and WISPs, Durham 13-17 July 2009 Aldo Morselli

    E-print Network

    Morselli, Aldo

    Durham, July 14 2009 Aldo Morselli, INFN Roma Tor Vergata 15th Patras Workshop on Axions, WIMPs and WISPs, Durham 13-17 July 2009 Aldo Morselli INFN Roma Tor Vergata Search for Dark matter in the sky in the Fermi, Atic and Pamela era #12;Durham, July 14 2009 Aldo Morselli, INFN Roma Tor Vergata 2 #12;Durham

  16. Limits on spin-independent WIMP-nucleon interactions from the two-tower run of the Cryogenic Dark Matter Search

    E-print Network

    CDMS Collaboration

    2005-09-09

    We report new results from the Cryogenic Dark Matter Search (CDMS II) at the Soudan Underground Laboratory. Two towers, each consisting of six detectors, were operated for 74.5 live days, giving spectrum-weighted exposures of 34 kg-d for germanium and 12 kg-d for silicon targets after cuts, averaged over recoil energies 10-100 keV for a WIMP mass of 60 GeV. A blind analysis was conducted, incorporating improved techniques for rejecting surface events. No WIMP signal exceeding expected backgrounds was observed. When combined with our previous results from Soudan, the 90% C.L. upper limit on the spin-independent WIMP-nucleon cross section is 1.6 x 10^{-43} cm^2 from Ge, and 3 x 10^{-42} cm^2 from Si, for a WIMP mass of 60 GeV. The combined limit from Ge (Si) is a factor of 2.5 (10) lower than our previous results, and constrains predictions of supersymmetric models.

  17. Final results of the EDELWEISS-II WIMP search using a 4-kg array of cryogenic germanium detectors with interleaved electrodes

    E-print Network

    EDELWEISS Collaboration; E. Armengaud; C. Augier; A. Benoît; L. Bergé; J. Blümer; A. Broniatowski; V. Brudanin; B. Censier; G. Chardin; M. Chapellier; F. Charlieux; P. Coulter; G. A. Cox; X. Defay; M. De Jesus; Y. Dolgorouki; J. Domange; L. Dumoulin; K. Eitel; D. Filosofov; N. Fourches; J. Gascon; G. Gerbier; J. Gironnet; M. Gros; S. Henry; S. Hervé; A. Juillard; H. Kluck; V. Kozlov; H. Kraus; V. A. Kudryavtsev; P. Loaiza; S. Marnieros; X-F. Navick; C. Nones; E. Olivieri; P. Pari; L. Pattavina; B. Paul; M. Robinson; S. Rozov; V. Sanglard; B. Schmidt; S. Scorza; S. Semikh; A-S. Torrento-Coello; L. Vagneron; M-A. Verdier; R. J. Walker; E. Yakushev

    2011-08-31

    The EDELWEISS-II collaboration has completed a direct search for WIMP dark matter with an array of ten 400-g cryogenic germanium detectors in operation at the Laboratoire Souterrain de Modane. The combined use of thermal phonon sensors and charge collection electrodes with an interleaved geometry enables the efficient rejection of gamma-induced radioactivity as well as near-surface interactions. A total effective exposure of 384 kg.d has been achieved, mostly coming from fourteen months of continuous operation. Five nuclear recoil candidates are observed above 20 keV, while the estimated background is 3.0 events. The result is interpreted in terms of limits on the cross-section of spin-independent interactions of WIMPs and nucleons. A cross-section of 4.4x10^-8 pb is excluded at 90%CL for a WIMP mass of 85 GeV. New constraints are also set on models where the WIMP-nucleon scattering is inelastic.

  18. Sensitivity, block sensitivity, and `block sensitivity of boolean functions

    E-print Network

    Mathieu, Claire

    Sensitivity, block sensitivity, and `­block sensitivity of boolean functions Claire Kenyon LRI, bat of the simplest, and block sensitivity one of the most useful, invariants of a boolean function. Nisan [8] and Nisan and Szegedy [9] have shown that block sensitivity is polynomially related to a number of measures

  19. Sensitive radars

    NASA Astrophysics Data System (ADS)

    Meer, David E.

    Prospective sensitive radar technologies with sensors operating at both RF and laser frequencies will enhance target detection, localization, classification, identification, and tracking capabilities. Ultrawideband radars operating at lower frequencies promise to detect stealthy targets and furnish simpler, lower cost, more reliable radars which can perform many of the functions of current high resolution radars. High resolution RF sensors for real-time recognition of noncooperative targets will be critical in future engagements, allowing detection of targets hidden in folliage. Laser radar technology will have its greatest impact in cruise missile and robotic vehicle navigation.

  20. Peanut sensitivity.

    PubMed

    Bush, R K; Taylor, S L; Nordlee, J A

    1989-01-01

    Peanuts are one of the most allergenic foods. The allergic reactions may vary in severity from mild urticaria to severe anaphylactic episodes and death. The prevalence of peanut sensitivity is unknown, but it may affect as many as 10% of allergic individuals. The chemistry of peanut proteins has been extensively studied. Two major protein fractions have been prepared from saline extracts of peanut flour, arachin and conarachin. A major peanut allergen termed "Peanut-1" has been isolated. However, a number of protein constituents, including the arachin and conarachin fractions, have been shown to be allergenic. The ability to diagnose peanut sensitivity accurately has been hampered by the lack of standardized peanut extracts. However, efforts are under way to prepare such standardized reagents. Treatment consists of avoiding peanut protein products and using self-administered epinephrine. A number of peanut protein-containing products are allergenic, although peanut oil is not. The peanut-allergic consumer should be instructed to carefully read labels of foods. This can at times, however, be misleading, because certain foods may be inadvertently contaminated by peanut proteins. PMID:2676716

  1. Non-thermal dark matter production from the electroweak phase transition: multi-TeV WIMPs and "baby-zillas"

    NASA Astrophysics Data System (ADS)

    Falkowski, Adam; No, Jose M.

    2013-02-01

    Particle production at the end of a first-order electroweak phase transition may be rather generic in theories beyond the standard model. Dark matter may then be abundantly produced by this mechanism if it has a sizable coupling to the Higgs field. For an electroweak phase transition occuring at a temperature T EW 50-100 GeV, non- thermally generated dark matter with mass M X > TeV will survive thermalization after the phase transition, and could then potentially account for the observed dark matter relic density in scenarios where a thermal dark matter component is either too small or absent. Dark matter in these scenarios could then either be multi-TeV WIMPs whose relic abundace is mostly generated at the electroweak phase transition, or " Baby-Zillas" with mass M GUT ? M X ? {v_{EW}} that never reach thermal equilibrium in the early universe.

  2. Non-thermal Dark Matter Production from the Electroweak Phase Transition: Multi-TeV WIMPs and "Baby-Zillas"

    E-print Network

    Adam Falkowski; Jose Miguel No

    2012-11-23

    Particle production at the end of a first-order electroweak phase transition may be rather generic in theories beyond the standard model. Dark matter may then be abundantly produced by this mechanism if it has a sizable coupling to the Higgs field. For an electroweak phase transition occuring at a temperature T_EW ~ 50-100 GeV, non-thermally generated dark matter with mass M_X > TeV will survive thermalization after the phase transition, and could then potentially account for the observed dark matter relic density in scenarios where a thermal dark matter component is either too small or absent. Dark matter in these scenarios could then either be multi-TeV WIMPs whose relic abundace is mostly generated at the electroweak phase transition, or "Baby-Zillas" with mass M_GUT >> M_X >> v_EW that never reach thermal equilibrium in the early universe.

  3. Sensitive and simplified analysis of natural and synthetic steroids in water and solids using on-line solid-phase extraction and microwave-assisted solvent extraction coupled to liquid chromatography tandem mass spectrometry atmospheric pressure photoionization.

    PubMed

    Snow, Daniel D; Damon-Powell, Teyona; Onanong, Sathaporn; Cassada, David A

    2013-02-01

    Analytical methods for the determination of several natural and synthetic steroids in water and solid samples were developed using liquid chromatography tandem mass spectrometry. Atmospheric pressure photoionization (APPI) in positive mode was used as the source which appeared to reduce background and interferences as compared to electrospray ionization. Toluene was identified as the most appropriate dopant and its concentration optimized to enhance ionization efficiency. Method detection limits were in the low-nanogram-per-liter range for water samples using on-line solid-phase extraction and near 0.2 ng/g using microwave-assisted solvent extraction for solid samples. This on-line method, using APPI as a source and toluene as a dopant, is beneficial as it saves time due to on-line extraction and reduces interference and matrix effects using gas-phase photoionization. Groundwater, wastewater, runoff, and soil samples were collected and analyzed using the method indicating that traces of several androgens, estrogens, and other steroid-like compounds do occur in samples impacted by animal waste. PMID:23208286

  4. Multivariate Ensemble Sensitivity with Localization

    NASA Astrophysics Data System (ADS)

    Hacker, Joshua; Lei, Lili

    2014-05-01

    So far in the literature, covariance localization (tapering) has not been applied when performing ensemble sensitivity analysis. Sampling error in computing the sensitivities via lagged covariances leads to an over-estimation of the impact of a perturbation. Most commonly when computing sensitivities, the analysis covariance is approximated with the corresponding diagonal matrix. Two consequences follow: (1) the multi-variate sensitivity is approximated by a univariate sensitivity, and (2) sampling error in off-diagonal elements are obviated. It is unknown, however, how much information is lost by ignoring the off-diagonal elements in the full covariance. When forecasts depend on many details of the previous analysis, it is reasonable to expect that the diagonal approximation is too severe. The purpose of this presentation is to clarify the effects of the diagonal approximation, and investigate the need for localization when off-diagonal elements are considered. Motivated by examples arising from sensitivities estimated within a cycling mesoscale ensemble data assimilation system, for easier interpretation we turn to the two-scale model first presented by Lorenz in 2005. We show that for most problems, an efficient matrix inversion is possible by finding a minimum-norm solution, and employing appropriate matrix factorization. Comparing the full inversion with off-diagonal elements, the fine-scale sensitivity estimates can be substantially different from those arising when the diagonal approximation is used. Localization on the sensitivity can be handled by an off-line empirical or Bayesian estimation technique. Because the sensitivity estimated from the full inversion is subject to sampling error, it is sensitive to the localization. The results show that compared to typical practices, more complete ensemble sensitivity formulations may be needed to draw robust inferences in general.

  5. Diatomic predissociation line widths

    NASA Technical Reports Server (NTRS)

    Child, M. S.

    1973-01-01

    Predissociation by rotation and curve crossing in diatomic molecules is discussed. The pattern of predissociation line widths is seen as providing a highly sensitive yardstick for the determination of unknown potential curves. In addition, the computation of such a pattern for given potential curves is considered a matter of routine, unless the predissociation happens to occur from an adiabatic potential curve. Analytic formulas are used to provide physical insight into the details of the predissociation pattern, to the extent that a direct inversion procedure is developed for determination of the repulsive potential curves for Type 1 predissociations.

  6. Limits on Spin-independent Couplings of Light Dark Matter WIMPs with a p-type Point-contact Germanium Detector

    NASA Astrophysics Data System (ADS)

    Lin, S. T.; Wong, H. T.

    New limits on spin-independent WIMP-nucleon coupling using 39.5 kg-days of data taken with a p-type point-contact germanium detector with fiducial mass of 840 g at the Kuo-Sheng Reactor Neutrino Laboratory (KSNL) is presented. Charactering and understanding the anomalous surface behaviour is of particular significance to this study. The slow rise-time of surface events is identified via software pulse shape analysis techniques. In addition, the signal-retaining and background-rejecting efficiencies are implied to clarify the actual bulk and surface events in the mixed regime at sub-keV range. Both efficiencies are evaluated with calibration sources and a novel n-type point-contact germanium detector. Efficiencies-corrected background spectra from the low-background facility at KSNL are derived. Part of the parameter space in cross-section versus WIMP-mass is probed and excluded.

  7. Limits on spin-dependent WIMP-proton cross-sections from the neutrino experiment at the Baksan Underground Scintillator Telescope

    E-print Network

    Olga Suvorova; Musabi Boliev; Sergei Demidov; Stanislav Mikheyev

    2012-11-12

    We present updated results of the Baksan Underground Scintillator Telescope in search for a signal from dark matter particles annihilating in the center of the Sun. Based on the performance of the Baksan telescope measuring upward through-going muons with energy larger 1 GeV, we confirm the absence of observable excess in arrival directions towards the Sun relatively the expectations from neutrinos of atmospheric origin for 24.12 years of live time. We conclude that the 90% C.L. upper limits on elastic scattering cross sections of dark matter WIMP (Weakly Interactive Massive Particle) off proton are comparable with correspondent limits of other operating neutrino telescopes. The best value of the limit is $3 \\times 10^{-4}$ picobarn in spin-dependent (SD) interaction of WIMP on proton for mass range about $100\\div200$ GeV.

  8. Atomic Parity Violation, Muon Pair Production in e+e - Collisions and Detection of CDM WIMP-Physics Related to Neutral Vector Boson D1

    NASA Astrophysics Data System (ADS)

    Senju, H.

    1999-11-01

    In our preon model there exists a neutral vector boson D1 which is an isoscalar partner of W(Z) in the vector boson octet. It is shown that the exchange of a D1 of about 1 TeV mass naturally explains a positive excess of the weak charge of atomic cesium recently observed. Other processes occurring through the D1 exchange are discussed, including the detection of CDM WIMP.

  9. Gravitational-wave sensitivity curves

    NASA Astrophysics Data System (ADS)

    Moore, C. J.; Cole, R. H.; Berry, C. P. L.

    2015-01-01

    There are several common conventions in use by the gravitational-wave community to describe the amplitude of sources and the sensitivity of detectors. These are frequently confused. We outline the merits of and differences between the various quantities used for parameterizing noise curves and characterizing gravitational-wave amplitudes. We conclude by producing plots that consistently compare different detectors. Similar figures can be generated on-line for general use at http://rhcole.com/apps/GWplotter.

  10. Gravitational-wave sensitivity curves

    E-print Network

    Christopher J. Moore; Robert H. Cole; Christopher P. L. Berry

    2014-12-11

    There are several common conventions in use by the gravitational-wave community to describe the amplitude of sources and the sensitivity of detectors. These are frequently confused. We outline the merits of and differences between the various quantities used for parameterizing noise curves and characterizing gravitational-wave amplitudes. We conclude by producing plots that consistently compare different detectors. Similar figures can be generated on-line for general use at \\url{http://rhcole.com/apps/GWplotter}.

  11. Differential Gene Expression Profiles of Radioresistant Non-Small-Cell Lung Cancer Cell Lines Established by Fractionated Irradiation: Tumor Protein p53-Inducible Protein 3 Confers Sensitivity to Ionizing Radiation

    SciTech Connect

    Lee, Young Sook; Oh, Jung-Hwa; Yoon, Seokjoo; Kwon, Myung-Sang

    2010-07-01

    Purpose: Despite the widespread use of radiotherapy as a local and regional modality for the treatment of cancer, some non-small-cell lung cancers commonly develop resistance to radiation. We thus sought to clarify the molecular mechanisms underlying resistance to radiation. Methods and Materials: We established the radioresistant cell line H460R from radiosensitive parental H460 cells. To identify the radioresistance-related genes, we performed microarray analysis and selected several candidate genes. Results: Clonogenic and MTT assays showed that H460R was 10-fold more resistant to radiation than H460. Microarray analysis indicated that the expression levels of 1,463 genes were altered more than 1.5-fold in H460R compared with parental H460. To evaluate the putative functional role, we selected one interesting gene tumor protein p53-inducible protein 3 (TP53I3), because that this gene was significantly downregulated in radioresistant H460R cells and that it was predicted to link p53-dependent cell death signaling. Interestingly, messenger ribonucleic acid expression of TP53I3 differed in X-ray-irradiated H460 and H460R cells, and overexpression of TP53I3 significantly affected the cellular radiosensitivity of H460R cells. Conclusions: These results show that H460R may be useful in searching for candidate genes that are responsible for radioresistance and elucidating the molecular mechanism of radioresistance.

  12. Sensitivity analysis of hydrodynamic stability operators

    NASA Technical Reports Server (NTRS)

    Schmid, Peter J.; Henningson, Dan S.; Khorrami, Mehdi R.; Malik, Mujeeb R.

    1992-01-01

    The eigenvalue sensitivity for hydrodynamic stability operators is investigated. Classical matrix perturbation techniques as well as the concept of epsilon-pseudoeigenvalues are applied to show that parts of the spectrum are highly sensitive to small perturbations. Applications are drawn from incompressible plane Couette, trailing line vortex flow and compressible Blasius boundary layer flow. Parametric studies indicate a monotonically increasing effect of the Reynolds number on the sensitivity. The phenomenon of eigenvalue sensitivity is due to the non-normality of the operators and their discrete matrix analogs and may be associated with large transient growth of the corresponding initial value problem.

  13. Familial melanoma associated with dominant ultraviolet radiation sensitivity

    SciTech Connect

    Ramsay, R.G.; Chen, P.; Imray, F.P.; Kidson, C.; Lavin, M.F.; Hockey, A.

    1982-07-01

    Sensitivity to ultraviolet radiation was studied in lymphoblastoid cell lines derived from 32 members of two families with histories of multiple primary melanomas in several generations. As assayed by colony formation in agar or by trypan blue exclusion following irradiation, cellular sensitivity showed a bimodal distribution. All persons with melanoma or multiple moles were in the sensitive group, while some family members exhibited responses similar to those of controls. Cells from four cases of sporadic melanoma showed normal levels of sensitivity. The data are consistent with a dominantly inherited ultraviolet light sensitivity associated with these examples of familial melanoma. Spontaneous and ultraviolet light-induced sister chromatid exchange frequencies were similar to those in control cell lines. No defect in excision repair was detected in any of the above cell lines, but the sensitive group showed postirradiation inhibition of DNA replication intermediate between controls and an excision-deficient xeroderma pigmentosum cell line.

  14. Line balance method helps protect offshore crude lines

    SciTech Connect

    Kunz, D.C. )

    1994-03-01

    Shell Pipe Line Corp. began a program in 1991 to install line integrity on pipelines it operates in the Gulf of Mexico. Shell Pipe Line studied a variety of means to do this, and selected the line-balance method to provide line integrity. The line-balance method sums all inputs and compares these to the outputs to determine the integrity of each pipeline segment. Shell developed and installed a system that uses recently introduced technology to implement this system in the offshore environment. The system has been in operation on many of the pipelines Shell operates in the Gulf of Mexico, and has proven to be a successful design. Shell will complete the installation of the line integrity system on all offshore pipelines within the next 2 years. Flow measurement accuracy influences the system's release sensitivity. The custody transfer meters at each platform used as the primary meters for each pipeline segment help keep the measurement as accurate as possible. Using these meters enabled Shell to obtain temperature-compensated barrels, which reduces volume variations due to temperature changes as the crude oil leaves the platform. The flow computer collected all measurement data as well as the status or control of pumps or valves from the platform.

  15. Sensitivity Analysis in Engineering

    NASA Technical Reports Server (NTRS)

    Adelman, Howard M. (compiler); Haftka, Raphael T. (compiler)

    1987-01-01

    The symposium proceedings presented focused primarily on sensitivity analysis of structural response. However, the first session, entitled, General and Multidisciplinary Sensitivity, focused on areas such as physics, chemistry, controls, and aerodynamics. The other four sessions were concerned with the sensitivity of structural systems modeled by finite elements. Session 2 dealt with Static Sensitivity Analysis and Applications; Session 3 with Eigenproblem Sensitivity Methods; Session 4 with Transient Sensitivity Analysis; and Session 5 with Shape Sensitivity Analysis.

  16. An assessment of the sensitivity of a low pressure time projection chamber to the direction of WIMP-induced nuclear recoils/

    E-print Network

    Henderson, Shawn Wesley

    2013-01-01

    Direct directional detection of dark matter could provide an unambiguous observation of dark matter due to the predicted directional anisotropy of dark matter particles in the galactic reference frame. The Dark Matter Time ...

  17. On the sensitivity of CTA to gamma-ray boxes from multi-TeV dark matter

    E-print Network

    Alejandro Ibarra; Anna S. Lamperstorfer; Sergio López Gehler; Miguel Pato; Gianfranco Bertone

    2015-03-23

    Collider, direct and indirect searches for dark matter have typically little or no sensitivity to weakly interacting massive particles (WIMPs) with masses above a few TeV. This rather unexplored regime can however be probed through the search for distinctive gamma-ray spectral features produced by the annihilation of WIMPs at very high energies. Here we present a dedicated search for gamma-ray boxes -- sharp spectral features that cannot be mimicked by astrophysical sources -- with the upcoming Cherenkov Telescope Array (CTA). Using realistic projections for the instrument performance and detailed background modelling, a profile likelihood analysis is implemented to derive the expected upper limits and sensitivity reach after 100 h of observations towards a $2^\\circ\\times2^\\circ$ region around the Galactic centre. Our results show that CTA will be able to probe gamma-ray boxes down to annihilation cross sections of $10^{-27}-10^{-26}\\,\\text{cm}^3\\text{/s}$ up to tens of TeV. We also identify a number of concrete particle physics models providing thermal dark matter candidates that can be used as target benchmarks in future search campaigns. This constitutes a golden opportunity for CTA to either discover or rule out multi-TeV thermal dark matter in a corner of parameter space where all other experimental efforts are basically insensitive.

  18. On the sensitivity of CTA to gamma-ray boxes from multi-TeV dark matter

    NASA Astrophysics Data System (ADS)

    Ibarra, Alejandro; Lamperstorfer, Anna S.; López-Gehler, Sergio; Pato, Miguel; Bertone, Gianfranco

    2015-09-01

    Collider, direct and indirect searches for dark matter have typically little or no sensitivity to weakly interacting massive particles (WIMPs) with masses above a few TeV. This rather unexplored regime can however be probed through the search for distinctive gamma-ray spectral features produced by the annihilation of WIMPs at very high energies. Here we present a dedicated search for gamma-ray boxes—sharp spectral features that cannot be mimicked by astrophysical sources—with the upcoming Cherenkov Telescope Array (CTA). Using realistic projections for the instrument performance and detailed background modelling, a profile likelihood analysis is implemented to derive the expected upper limits and sensitivity reach after 100 h of observations towards a 2°×2° region around the Galactic centre. Our results show that CTA will be able to probe gamma-ray boxes down to annihilation cross sections of 10?27?10?26 cm3/s up to tens of TeV. We also identify a number of concrete particle physics models providing thermal dark matter candidates that can be used as target benchmarks in future search campaigns. This constitutes a golden opportunity for CTA to either discover or rule out multi-TeV thermal dark matter in a corner of parameter space where all other experimental efforts are basically insensitive.

  19. Light sensitivity in a vertebrate mechanoreceptor?

    PubMed

    Baker, Gary E; de Grip, Willem J; Turton, Michael; Wagner, Hans-Joachim; Foster, Russell G; Douglas, Ron H

    2015-09-01

    Using immunohistochemistry and western blot analysis, we demonstrate that melanopsin is localised in cells around the central pore of lateral line neuromasts in the African clawed frog, Xenopus laevis. Since melanopsin is a known photoreceptor pigment with diverse functions in vertebrates, we suggest that the lateral line of Xenopus laevis, which is primarily a mechanoreceptor, might also be light sensitive. Potential functions of such photosensitivity are discussed, including its role in mediating locomotor responses following dermal illumination. PMID:26206352

  20. The local dark matter phase-space density and impact on WIMP direct detection

    NASA Astrophysics Data System (ADS)

    Catena, Riccardo; Ullio, Piero

    2012-05-01

    We present a new determination of the local dark matter phase-space density. This result is obtained implementing, in the limit of isotropic velocity distribution and spherical symmetry, Eddington's inversion formula, which links univocally the dark matter distribution function to the density profile, and applying, within a Bayesian framework, a Markov Chain Monte Carlo algorithm to sample mass models for the Milky Way against a broad and variegated sample of dynamical constraints. We consider three possible choices for the dark matter density profile, namely the Einasto, NFW and Burkert profiles, finding that the velocity dispersion, which characterizes the width in the distribution, tends to be larger for the Burkert case, while the escape velocity depends very weakly on the profile, with the mean value we obtain being in very good agreement with estimates from stellar kinematics. The derived dark matter phase-space densities differ significantly — most dramatically in the high velocity tails — from the model usually taken as a reference in dark matter detection studies, a Maxwell-Boltzmann distribution with velocity dispersion fixed in terms of the local circular velocity and with a sharp truncation at a given value of the escape velocity. We discuss the impact of astrophysical uncertainties on dark matter scattering rates and direct detection exclusion limits, considering a few sample cases and showing that the most sensitive ones are those for light dark matter particles and for particles scattering inelastically. As a general trend, regardless of the assumed profile, when adopting a self-consistent phase-space density, we find that rates are larger, and hence exclusion limits stronger, than with the standard Maxwell-Boltzmann approximation. Tools for applying our result on the local dark matter phase-space density to other dark matter candidates or experimental setups are provided.

  1. Case for a 700+GeV WIMP: Cosmic ray spectra from PAMELA, Fermi, and ATIC

    SciTech Connect

    Cholis, Ilias; Goodenough, Lisa; Weiner, Neal; Dobler, Gregory; Finkbeiner, Douglas P.

    2009-12-15

    Multiple lines of evidence indicate an anomalous injection of high-energy e{sup +}e{sup -} in the galactic halo. The recent e{sup +} fraction spectrum from the payload for antimatter matter exploration and light-nuclei astrophysics (PAMELA) shows a sharp rise up to 100 GeV. The Fermi gamma-ray space telescope has found a significant hardening of the e{sup +}e{sup -} cosmic-ray spectrum above 100 GeV, with a break, confirmed by HESS at around 1 TeV. The advanced thin ionization calorimeter (ATIC) has also detected a similar excess, falling back to the expected spectrum at 1 TeV and above. Excess microwaves towards the galactic center in the WMAP data are consistent with hard synchrotron radiation from a population of 10-100 GeV e{sup +}e{sup -} (the WMAP 'Haze'). We argue that dark matter annihilations can provide a consistent explanation of all of these data, focusing on dominantly leptonic modes, either directly or through a new light boson. Normalizing the signal to the highest energy evidence (Fermi and HESS), we find that similar cross sections provide good fits to PAMELA and the Haze, and that both the required cross section and annihilation modes are achievable in models with Sommerfeld-enhanced annihilation. These models naturally predict significant production of gamma rays in the galactic center via a variety of mechanisms. Most notably, there is a robust inverse-Compton scattered (ICS) gamma-ray signal arising from the energetic electrons and positrons, detectable at Fermi/GLAST energies, which should provide smoking gun evidence for this production.

  2. Evaluation of the neutron background in an HPGe target for WIMP direct detection when using a reactor neutrino detector as a neutron veto system

    SciTech Connect

    Ji, Xiangpan; Xu, Ye Lin, Junsong; Feng, Yulong; Li, Haolin

    2013-11-15

    A direct WIMP (weakly interacting massive particle) detector with a neutron veto system is designed to better reject neutrons. The experimental configuration is studied in this paper involves 984 Ge modules placed inside a reactor-neutrino detector. The neutrino detector is used as a neutron veto device. The neutron background for the experimental design is estimated using the Geant4 simulation. The results show that the neutron background can decrease to O(0.01) events per year per tonne of high-purity germanium and it can be ignored in comparison with electron recoils.

  3. Pressure Sensitive Paints

    NASA Technical Reports Server (NTRS)

    Liu, Tianshu; Bencic, T.; Sullivan, J. P.

    1999-01-01

    This article reviews new advances and applications of pressure sensitive paints in aerodynamic testing. Emphasis is placed on important technical aspects of pressure sensitive paint including instrumentation, data processing, and uncertainty analysis.

  4. Focus Sensitive Coordination

    E-print Network

    Hulsey, Sarah McNearney

    2008-01-01

    This thesis investigates the role of the Focus Sensitive Operators (FSOs) even and also when found inside of a coordination. Coordinations of this form are called Focus Sensitive Coordinations (FSC) and include or even, ...

  5. Literature and Social Sensitivity.

    ERIC Educational Resources Information Center

    Loban, Walter

    Focusing on the responses of adolescents to literature "involving values based on the concept of human dignity," this study examined two groups of adolescents (60 students each) in grades 8-12. The two groups represented extremes of social sensitivity: highly sensitive and least sensitive to the feelings of others. Teachers read aloud 10 short…

  6. The DRIFT Dark Matter Project: Directionality, Sensitivity, and Environmental Backgrounds 

    E-print Network

    Plank, Steven J S

    2008-01-01

    It is now largely accepted that dark matter, and more specifically, Weakly Interacting Massive Particles (WIMPs), constitute the majority of the mass in our Universe. Within this thesis are presented: (i) an overview of ...

  7. Sensitivity Test Analysis

    Energy Science and Technology Software Center (ESTSC)

    1992-02-20

    SENSIT,MUSIG,COMSEN is a set of three related programs for sensitivity test analysis. SENSIT conducts sensitivity tests. These tests are also known as threshold tests, LD50 tests, gap tests, drop weight tests, etc. SENSIT interactively instructs the experimenter on the proper level at which to stress the next specimen, based on the results of previous responses. MUSIG analyzes the results of a sensitivity test to determine the mean and standard deviation of the underlying population bymore »computing maximum likelihood estimates of these parameters. MUSIG also computes likelihood ratio joint confidence regions and individual confidence intervals. COMSEN compares the results of two sensitivity tests to see if the underlying populations are significantly different. COMSEN provides an unbiased method of distinguishing between statistical variation of the estimates of the parameters of the population and true population difference.« less

  8. Wimps Need Not Apply.

    ERIC Educational Resources Information Center

    Walsh, Michael H.

    1991-01-01

    A corporate leader argues that higher education leaders must be prepared to manage change, and suggests focusing on results, communicating straight and openly, and delegating responsibility. An institutionwide communication program and greater efficiency are key elements in management change. (MSE)

  9. Abstract Line Designs

    ERIC Educational Resources Information Center

    Nevinskas, Nancy

    2011-01-01

    In this article, the author describes a unit on the exploration of line. The unit was composed of two individual line lessons. In the first lesson, students were introduced to line as an element of design. They were asked to describe different types of lines, and look for them in art reproductions. The second lesson in the unit involved painting…

  10. Easy Observation of Infrared Spectral Lines

    ERIC Educational Resources Information Center

    Cortel, Adolf

    2012-01-01

    The spectra of some chemical elements display intense infrared (IR) lines that can be used more effectively than the ones in the visible region for identification purposes. A simple setup, based on the IR sensitivity of a handycam in nightshot mode, is described to record the visible as well as the IR spectra from decorative bulbs or salts on the…

  11. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    NASA Astrophysics Data System (ADS)

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Oliveira, C. A. B.; Nygren, D.

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase o_ers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at the 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.

  12. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    SciTech Connect

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Oliveira, C. A.B.; Nygren, D.

    2015-03-24

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase offers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at the 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.

  13. Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

    DOE PAGESBeta

    Renner, J.; Gehman, V. M.; Goldschmidt, A.; Oliveira, C. A.B.; Nygren, D.

    2015-03-24

    Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase offers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at themore »136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.« less

  14. Pharmacogenomic agreement between two cancer cell line data sets.

    PubMed

    2015-12-01

    Large cancer cell line collections broadly capture the genomic diversity of human cancers and provide valuable insight into anti-cancer drug response. Here we show substantial agreement and biological consilience between drug sensitivity measurements and their associated genomic predictors from two publicly available large-scale pharmacogenomics resources: The Cancer Cell Line Encyclopedia and the Genomics of Drug Sensitivity in Cancer databases. PMID:26570998

  15. Flash Mob Project Creates Awareness of Environmental Sensitivities: Making "Multiple Chemical Sensitivity" a Household Name

    ERIC Educational Resources Information Center

    Smith, Melva Gail

    2011-01-01

    Having severe Asthma and trying to maintain a social life isn't easy, but when one adds the disability of Multiple Chemical Sensitivity (MCS) to the combination, the challenges become even tougher. As a dancer with both Asthma and MCS, the author was forced to give up the sport for 15 years before finding a group of line dancers that were…

  16. Fabrics Protect Sensitive Skin from UV Rays

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Late Johnson Space Center engineer Dr. Robert Dotts headed a team to develop cool suits for children suffering from life-threatening sun sensitivities. Dotts hoped to develop ultraviolet-blocking technology in a fabric that -- unlike in a bulky space suit -- could remain comfortable, light, and breathable in the sun and heat. The team worked with SPF 4 US LLC (SPF) of Madison, Wisconsin to design ultraviolet-blocking cool suits, which protect sun-sensitive patients and enable them to experience life outdoors safely. Using knowledge gained during the NASA collaboration, SPF created an entire line of ultraviolet-blocking apparel.

  17. Tuned cavity magnetometer sensitivity.

    SciTech Connect

    Okandan, Murat; Schwindt, Peter

    2009-09-01

    We have developed a high sensitivity (sensitivity levels.

  18. Mentoring Emotionally Sensitive Individuals.

    ERIC Educational Resources Information Center

    Shaughnessy, Michael F.; Self, Elizabeth

    Mentoring individuals who are gifted, talented, and creative, but somewhat emotionally sensitive is a challenging and provocative arena. Several reasons individuals experience heightened sensitivity include: lack of nurturing, abuse, alcoholism in the family, low self-esteem, unrealistic parental expectations, and parental pressure to achieve.…

  19. Are Psychopaths Morally Sensitive?

    ERIC Educational Resources Information Center

    Maxwell, Bruce; Le Sage, Leonie

    2009-01-01

    Philosophical and psychological opinion is divided over whether moral sensitivity, understood as the ability to pick out a situation's morally salient features, necessarily involves emotional engagement. This paper seeks to offer insight into this question. It reasons that if moral sensitivity does draw significantly on affective capacities of…

  20. Mechanism of cinnamaldehyde sensitization.

    PubMed

    Majeti, V A; Suskind, R R

    1977-02-01

    The skin sensitization of cinnamaldehyde is probably initiated by the reaction of cinnamaldehyde with epsilon-amino groups on protein side chains. Alpha-Substituted cinnamaldehydes, which are known not to be skin sensitizers, react very slowly or not at all with amines in comparison with cinnamaldehyde. PMID:844298