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1. Investigating the sources of low-energy events in a SuperCDMS-HVeV detector

Author

SuperCDMS Collaboration, Albakry, M. F., Alkhatib, I., Amaral, D. W. P., Aralis, T., Aramaki, T., Arnquist, I. J., Langroudy, I. Ataee, Azadbakht, E., Banik, S., Bathurst, C., Bauer, D. A., Bhattacharyya, R., Brink, P. L., Bunker, R., Cabrera, B., Calkins, R., Cameron, R. A., Cartaro, C., Cerdeño, D. G., Chang, Y. -Y., Chaudhuri, M., Chen, R., Chott, N., Cooley, J., Coombes, H., Corbett, J., Cushman, P., De Brienne, F., Dharani, S., di Vacri, M. L., Diamond, M. D., Fascione, E., Figueroa-Feliciano, E., Fink, C. W., Fouts, K., Fritts, M., Gerbier, G., Germond, R., Ghaith, M., Golwala, S. R., Hall, J., Hassan, N., Hines, B. A., Hollister, M. I., Hong, Z., Hoppe, E. W., Hsu, L., Huber, M. E., Iyer, V., Jastram, A., Kashyap, V. K. S., Kelsey, M. H., Kubik, A., Kurinsky, N. A., Lawrence, R. E., Lee, M., Li, A., Liu, J., Liu, Y., Loer, B., Asamar, E. Lopez, Lukens, P., MacFarlane, D. B., Mahapatra, R., Mandic, V., Mast, N., Mayer, A. J., Theenhausen, H. Meyer zu, Michaud, É., Michielin, E., Mirabolfathi, N., Mohanty, B., Nagorny, S., Nelson, J., Neog, H., Novati, V., Orrell, J. L., Osborne, M. D., Oser, S. M., Page, W. A., Partridge, R., Pedreros, D. S., Podviianiuk, R., Ponce, F., Poudel, S., Pradeep, A., Pyle, M., Rau, W., Reid, E., Ren, R., Reynolds, T., Roberts, A., Robinson, A. E., Saab, T., Sadoulet, B., Saikia, I., Sander, J., Sattari, A., Schmidt, B., Schnee, R. W., Scorza, S., Serfass, B., Poudel, S. S., Sincavage, D. J., Stanford, C., Street, J., Sun, H., Thasrawala, F. K., Toback, D., Underwood, R., Verma, S., Villano, A. N., von Krosigk, B., Watkins, S. L., Wen, O., Williams, Z., Wilson, M. J., Winchell, J., Wykoff, K., Yellin, S., Young, B. A., Yu, T. C., Zatschler, B., Zatschler, S., Zaytsev, A., Zhang, E., Zheng, L., and Zuber, S.

Subjects
High Energy Physics - Experiment (hep-ex), Cosmology and Nongalactic Astrophysics (astro-ph.CO), Physics - Instrumentation and Detectors, Physics, FOS: Physical sciences, ddc:530, Instrumentation and Detectors (physics.ins-det), High Energy Physics - Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Recent experiments searching for sub−GeV/c2 dark matter have observed event excesses close to their respective energy thresholds. Although specific to the individual technologies, the measured excess event rates have been consistently reported at or below event energies of a few-hundred eV, or with charges of a few electron-hole pairs. In the present work, we operated a 1-g silicon SuperCDMS-HVeV detector at three voltages across the crystal (0, 60 and 100 V). The 0 V data show an excess of events in the tens of eV region. Despite this event excess, we demonstrate the ability to set a competitive exclusion limit on the spin-independent dark matter–nucleon elastic scattering cross section for dark matter masses of O(100) MeV/c2, enabled by operation of the detector at 0 V potential and achievement of a very low O(10) eV threshold for nuclear recoils. Comparing the data acquired at 0, 60 and 100 V potentials across the crystal, we investigated possible sources of the unexpected events observed at low energy. The data indicate that the dominant contribution to the excess is consistent with a hypothesized luminescence from the printed circuit boards used in the detector holder.

Published
2022

2. Constraints on Lightly Ionizing Particles from CDMSlite

Author

SuperCDMS Collaboration, Alkhatib, I., Amaral, D. W. P., Aralis, T., Aramaki, T., Arnquist, I. J., Langroudy, I. Ataee, Azadbakht, E., Banik, S., Barker, D., Bathurst, C., Bauer, D. A., Bezerra, L. V. S., Bhattacharyya, R., Bowles, M. A., Brink, P. L., Bunker, R., Cabrera, B., Calkins, R., Cameron, R. A., Cartaro, C., Cerdeño, D. G., Chang, Y. -Y., Chaudhuri, M., Chen, R., Chott, N., Cooley, J., Coombes, H., Corbett, J., Cushman, P., De Brienne, F., di Vacri, M. L., Diamond, M. D., Fascione, E., Figueroa-Feliciano, E., Fink, C. W., Fouts, K., Fritts, M., Gerbier, G., Germond, R., Ghaith, M., Golwala, S. R., Harris, H. R., Hines, B. A., Hollister, M. I., Hong, Z., Hoppe, E. W., Hsu, L., Huber, M. E., Iyer, V., Jardin, D., Jastram, A., Kashyap, V. K. S., Kelsey, M. H., Kubik, A., Kurinsky, N. A., Lawrence, R. E., Li, A., Loer, B., Asamar, E. Lopez, Lukens, P., MacFarlane, D. B., Mahapatra, R., Mandic, V., Mast, N., Mayer, A. J., Theenhausen, H. Meyer zu, Michaud, É. M., Michielin, E., Mirabolfathi, N., Mohanty, B., Mendoza, J. D. Morales, Nagorny, S., Nelson, J., Neog, H., Novati, V., Orrell, J. L., Oser, S. M., Page, W. A., Partridge, R., Podviianiuk, R., Ponce, F., Poudel, S., Pradeep, A., Pyle, M., Rau, W., Reid, E., Ren, R., Reynolds, T., Roberts, A., Robinson, A. E., Saab, T., Sadoulet, B., Sander, J., Sattari, A., Schnee, R. W., Scorza, S., Serfass, B., Sincavage, D. J., Stanford, C., Street, J., Toback, D., Underwood, R., Verma, S., Villano, A. N., von Krosigk, B., Watkins, S. L., Wilson, J. S., Wilson, M. J., Winchell, J., Wright, D. H., Yellin, S., Young, B. A., Yu, T. C., Zhang, E., Zhang, H. G., Zhao, X., Zheng, L., and UAM. Departamento de Física Teórica

Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO), Physics - Instrumentation and Detectors, Ionization Thresholds, General Physics and Astronomy, FOS: Physical sciences, Cryogenic Dark Matter Searches, 01 natural sciences, Electric charge, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Interval Methods, Recoil, High Energy Physics - Phenomenology (hep-ph), Ionization, 0103 physical sciences, Sensitivity (control systems), 010306 general physics, Ionizing Particles, Velocity Parameters, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Range (particle radiation), 010308 nuclear & particles physics, Física, Charge (physics), Instrumentation and Detectors (physics.ins-det), Recoil Energies, Efficient Detection, High Energy Physics - Phenomenology, Direct Detection, Cover (topology), 13. Climate action, Atomic physics, Astrophysics - High Energy Astrophysical Phenomena, Intensity (heat transfer), Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM, The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e / (3 × 105), as well as the strongest limits for charge ≤ e / 160, with a minimum vertical intensity of 1.36 × 10−7 cm−2 s−1 sr−1 at charge e /160. These results apply over a wide range of LIP masses (5 MeV / c2 to 100 TeV / c2) and cover a wide range of βγ values (0.1–106), thus excluding nonrelativistic LIPs with βγ as small as 0.1 for the first time

Published
2020

3. WIMP-Search Results from the Second CDMSlite Run

Author

SuperCDMS Collaboration, Agnese, R., Anderson, A. J., 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., and Zhang, J.

Subjects
Physics - Instrumentation and Detectors, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Physics::Instrumentation and Detectors, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Instrumentation and Detectors (physics.ins-det), High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), High Energy Physics::Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, Nuclear Experiment, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

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/$c^2$., Comment: 6 pages, 4 figures. v2 Matches the accepted version in PRL

Published
2015
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6. First direct limits on lightly ionizing particles with electric charge less than e/6

Author

Agnese, R., Anderson, A. J., Balakishiyeva, 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., Cerdeno, 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., Jastram, A., Kamaev, O., Kara, B., Kelsey, M. H., Kennedy, A., Kiveni, M., Koch, K., Leder, A., Loer, B., Lopez Asamar, E., Mahapatra, R., Mandic, V., Martinez, C., McCarthy, K. A., Mirabolfathi, N., Moffatt, R. A., Moore, D. C., Nelson, H., Nelson, R. H., Ogburn, R. W., 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., Upadhyayula, S., Villano, A. N., Welliver, B., Wright, D. H., Yellin, S., Yen, J. J., Young, B. A., Zhang, J., (CDMS Collaboration), and UAM. Departamento de Física Teórica

Subjects
General Physics, Particle physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Physics - Instrumentation and Detectors, CDMS Collaboration, Direct detection, Dark matter, FOS: Physical sciences, General Physics and Astronomy, Parameter space, Electric charge, Mathematical Sciences, High Energy Physics - Experiment, Standard Model, Relativistic particle, Nuclear physics, High Energy Physics - Experiment (hep-ex), Engineering, physics.ins-det, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Physics, Stacked detectors, hep-ex, Fractional charges, Física, Charge (physics), Instrumentation and Detectors (physics.ins-det), Ionizing particles, Physical Sciences, astro-ph.CO, Subatomic particle, Cryogenic Dark Matter Search, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Artículo escrito por muchos autores, sólo se referencian el primero, los autores que firman como Universidad Autónoma de Madrid y el grupo de colaboración en el caso de que aparezca en el artículo, While the standard model of particle physics does not include free particles with fractional charge, experimental searches have not ruled out their existence. We report results from the Cryogenic Dark Matter Search (CDMS II) experiment that give the first direct-detection limits for cosmogenically produced relativistic particles with electric charge lower than e/6. A search for tracks in the six stacked detectors of each of two of the CDMS II towers finds no candidates, thereby excluding new parameter space for particles with electric charges between e/6 and e/200, This work is supported in part by the National Science Foundation, by the U.S. Department of Energy, by NSERC Canada, and by MultiDark (Spanish MINECO). Fermilab is operated by the Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359. SLAC is operated under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy

Published
2014

7. Search for Low-Mass WIMPs with SuperCDMS

Author

Agnese, R., Anderson, A. J., Asai, M., Balakishiyeva, D., Thakur, R. Basu, Bauer, D. A., Beaty, J., Billard, J., Borgland, A., Bowles, M. A., Brandt, D., Brink, P. L., Bunker, R., Cabrera, B., Caldwell, D. O., Cerdeno, D. G., Chagani, H., Chen, Y., Cherry, M., Cooley, J., Cornell, B., Crewdson, C. H., Cushman, P., Daal, M., DeVaney, D., Di Stefano, P. C. F., Silva, E. Do Couto E, Doughty, T., Esteban, L., Fallows, S., Figueroa-Feliciano, E., Godfrey, G. L., Golwala, S. R., Hall, J., Hansen, S., Harris, H. R., Hertel, S. A., Hines, B. A., Hofer, T., Holmgren, D., Hsu, L., Huber, M. E., Jastram, A., Kamaev, O., Kara, B., Kelsey, M. H., Kenany, S., Kennedy, A., Kiveni, M., Koch, K., Leder, A., Loer, B., Asamar, E. Lopez, Mahapatra, R., Mandic, V., Martinez, C., McCarthy, K. A., Mirabolfathi, N., Moffatt, R. A., Nelson, R. H., Novak, L., Page, K., Partridge, R., Pepin, M., Phipps, A., Platt, M., Prasad, K., Pyle, M., Qiu, H., Rau, W., Redl, P., Reisetter, A., Resch, R. W., Ricci, Y., Ruschman, M., Saab, T., Sadoulet, B., Sander, J., Schmitt, R. L., Schneck, K., Schnee, R. W., Scorza, S., Seitz, D. N., Serfass, B., Shank, B., Speller, D., Tomada, A., Upadhyayula, S., Villano, A. N., Welliver, B., Wright, D. H., Yellin, S., Yen, J. J., Young, B. A., and Zhang, J.

Subjects
High Energy Physics - Experiment (hep-ex), Physics - Instrumentation and Detectors, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Physics::Instrumentation and Detectors, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, High Energy Physics::Experiment, Astrophysics::Cosmology and Extragalactic Astrophysics, Instrumentation and Detectors (physics.ins-det), Nuclear Experiment, High Energy Physics - Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We report a first search for weakly interacting massive particles (WIMPs) using the background rejection capabilities of SuperCDMS. An exposure of 577 kg-days was analyzed for WIMPs with mass < 30 GeV/c2, with the signal region blinded. Eleven events were observed after unblinding. We set an upper limit on the spin-independent WIMP-nucleon cross section of 1.2e-42 cm2 at 8 GeV/c2. This result is in tension with WIMP interpretations of recent experiments and probes new parameter space for WIMP-nucleon scattering for WIMP masses < 6 GeV/c2., 6 pages, 4 figures; figure 1 updated, submitted to Phys. Rev. Lett

Published
2014
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8. Maximum Likelihood Analysis of Low Energy CDMS II Germanium Data

Author

SuperCDMS Collaboration, Agnese, R., Anderson, A. J., Balakishiyeva, 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., Cerdeno, 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., Fritts, M., Godfrey, G. L., Golwala, S. R., Graham, M., Hall, J., Harris, H. R., Hertel, S. A., Hofer, T., Holmgren, D., Hsu, L., Huber, M. E., Jastram, A., Kamaev, O., Kara, B., Kelsey, M. H., Kennedy, A., Kiveni, M., Koch, K., Leder, A., Loer, B., Asamar, E. Lopez, Mahapatra, R., Mandic, V., Martinez, C., McCarthy, K. A., Mirabolfathi, N., Moffatt, R. A., Moore, D. C., Nelson, R. H., 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., Upadhyayula, S., Villano, A. N., Welliver, B., Wright, D. H., Yellin, S., Yen, J. J., Young, B. A., Zhang, J., and UAM. Departamento de Física Teórica

Subjects
Nuclear and High Energy Physics, Particle physics, Physics - Instrumentation and Detectors, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Calibration (statistics), Dark matter, Massive particle, chemistry.chemical_element, FOS: Physical sciences, Germanium, 01 natural sciences, Signal, Atomic, Particle and Plasma Physics, WIMP, 0103 physical sciences, Nuclear, 010306 general physics, physics.ins-det, Instrumentation and Methods for Astrophysics (astro-ph.IM), Physics, Quantum Physics, 010308 nuclear & particles physics, Física, Molecular, Instrumentation and Detectors (physics.ins-det), Nuclear & Particles Physics, chemistry, Weakly interacting massive particles, astro-ph.CO, Cryogenic Dark Matter Search, Astrophysics - Instrumentation and Methods for Astrophysics, Astronomical and Space Sciences, Astrophysics - Cosmology and Nongalactic Astrophysics, astro-ph.IM
Abstract

Artículo escrito por un elevado número de autores, sólo se referencian el primero, los autores que firman como Universidad Autónoma de Madrid y el grupo de colaboración en el caso de que aparezca en el artículo, We report on the results of a search for a Weakly Interacting Massive Particle (WIMP) signal in low-energy data of the Cryogenic Dark Matter Search experiment using a maximum likelihood analysis. A background model is constructed using geant4 to simulate the surface-event background from Pb210 decay-chain events, while using independent calibration data to model the gamma background. Fitting this background model to the data results in no statistically significant WIMP component. In addition, we perform fits using an analytic ad hoc background model proposed by Collar and Fields, who claimed to find a large excess of signal-like events in our data. We confirm the strong preference for a signal hypothesis in their analysis under these assumptions, but excesses are observed in both single- and multiple-scatter events, which implies the signal is not caused by WIMPs, but rather reflects the inadequacy of their background model, This work is supported in part by the National Science Foundation, by the United States Department of Energy, by NSERC Canada, and by MultiDark (Spanish MINECO). Fermilab is operated by the Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359. SLAC is operated under Contract No. DE-AC02-76SF00515 with the United States Department of Energy

Published
2014
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10. CDMSlite: A Search for Low-Mass WIMPs using Voltage-Assisted Calorimetric Ionization Detection in the SuperCDMS Experiment

Author

Agnese, R., Anderson, A. J., Asai, M., Balakishiyeva, 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., Cerdeno, D. G., Chagani, H., 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., Jastram, A., Kamaev, O., Kara, B., Kelsey, M. H., Kennedy, A., Kiveni, M., Koch, K., Loer, B., Asamar, E. Lopez, Mahapatra, R., Mandic, V., Martinez, C., McCarthy, K. A., Mirabolfathi, N., Moffatt, R. A., Moore, D. C., Nadeau, P., Nelson, R. H., Page, K., Partridge, R., Pepin, M., Phipps, A., Prasad, K., Pyle, M., Qiu, H., Rau, W., Redl, P., Reisetter, A., Ricci, Y., Saab, T., Sadoulet, B., Sander, J., Schneck, K., Schnee, R. W., Scorza, S., Serfass, B., Shank, B., Speller, D., Villano, A. N., Welliver, B., Wright, D. H., Yellin, S., Yen, J. J., Young, B. A., and Zhang, J.

Subjects
High Energy Physics - Experiment (hep-ex), Physics - Instrumentation and Detectors, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Physics::Instrumentation and Detectors, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, High Energy Physics::Experiment, Astrophysics::Cosmology and Extragalactic Astrophysics, Instrumentation and Detectors (physics.ins-det), Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment
Abstract

SuperCDMS is an experiment designed to directly detect Weakly Interacting Massive Particles (WIMPs), a favored candidate for dark matter ubiquitous in the Universe. In this paper, we present WIMP-search results using a calorimetric technique we call CDMSlite, which relies on voltage- assisted Luke-Neganov amplification of the ionization energy deposited by particle interactions. The data were collected with a single 0.6 kg germanium detector running for 10 live days at the Soudan Underground Laboratory. A low energy threshold of 170 eVee (electron equivalent) was obtained, which allows us to constrain new WIMP-nucleon spin-independent parameter space for WIMP masses below 6 GeV/c2., Comment: 7 pages, 4 figures

Published
2013
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11. Search for annual modulation in low-energy CDMS-II data

Author

CDMS Collaboration, Ahmed, Z., Akerib, D. S., Anderson, A. J., Arrenberg, S., Bailey, C. N., Balakishiyeva, D., Baudis, L., Bauer, D. A., Brink, P. L., Bruch, T., Bunker, R., Cabrera, B., Caldwell, D. O., Cooley, J., Cushman, P., Daal, M., DeJongh, F., Di Stefano, P. C. F., Dragowsky, M. R., Fallows, S., Figueroa-Feliciano, E., Filippini, J., Fox, J., Fritts, M., Golwala, S. R., Hall, J., Hertel, S. A., Hofer, T., Holmgren, D., Hsu, L., Huber, M. E., Kamaev, O., Kiveni, M., Kos, M., Leman, S. W., Liu, S., Mahapatra, R., Mandic, V., McCarthy, K. A., Mirabolfathi, N., Moore, D. C., Nelson, H., Ogburn, R. W., Phipps, A., Prasad, K., Pyle, M., Qiu, X., Rau, W., Reisetter, A., Ricci, Y., Saab, T., Sadoulet, B., Sander, J., Schnee, R. W., Seitz, D., Serfass, B., Speller, D., Sundqvist, K. M., Tarka, M., Thakur, R. B., Villano, A. N., Welliver, B., Yellin, S., Yoo, J., Young, B. A., and Zhang, J.

Subjects
High Energy Physics - Experiment (hep-ex), Cosmology and Nongalactic Astrophysics (astro-ph.CO), FOS: Physical sciences, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment
Abstract

We report limits on annual modulation of the low-energy event rate from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Such a modulation could be produced by interactions from Weakly Interacting Massive Particles (WIMPs) with masses ~10 GeV/c^2. We find no evidence for annual modulation in the event rate of veto-anticoincident single-detector interactions consistent with nuclear recoils, and constrain the magnitude of any modulation to 98% confidence. For events consistent with electron recoils, no significant modulation is observed for either single- or multiple-detector interactions in the 3.0-7.4 keVee range., 5 pages, plus 8 pages supplementary materials

Published
2012
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12. Phonon Quasidiffusion in Cryogenic Dark Matter Search Large Germanium Detectors

Author

Leman, S. W., Cabrera, B., McCarthy, K. A., Pyle, M., Resch, R., Sadoulet, B., Sundqvist, K. M., Brink, P. L., Cherry, M., Silva, E. Do Couto E, Figueroa-Feliciano, E., Mirabolfathi, N., Serfass, B., and Tomada, A.

Subjects
Condensed Matter - Materials Science, High Energy Physics - Experiment (hep-ex), Physics - Instrumentation and Detectors, Physics::Instrumentation and Detectors, Astrophysics::Instrumentation and Methods for Astrophysics, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), High Energy Physics - Experiment
Abstract

We present results on quasidiffusion studies in large, 3 inch diameter, 1 inch thick [100] high purity germanium crystals, cooled to 50 mK in the vacuum of a dilution refrigerator, and exposed with 59.5 keV gamma-rays from an Am-241 calibration source. We compare data obtained in two different detector types, with different phonon sensor area coverage, with results from a Monte Carlo. The Monte Carlo includes phonon quasidiffusion and the generation of phonons created by charge carriers as they are drifted across the detector by ionization readout channels., Comment: 13 pages, 12 figures, PHONONS201 conference proceedings; http://psroc.phys.ntu.edu.tw/cjp/download.php?d=4&pid=2718

Published
2011
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13. Concluding remarks

Author

Sanchez-Bayo, FP, Van den Brink, P, Mann, RM, Sanchez-Bayo, F, van den Brink, PJ, and Mann, RM

Abstract

The new millennium started with a legacy of unprecedented contamination of the world ecosystems left in the wake of the various activities of humankind. Chemical pollutants have become so diverse (see Chapter 1) and widespread that there is hardly any region of the world that is not currently affected by their impacts. With the exception, perhaps, of the desert wilderness areas (for which information on pollution is still lacking), every other ecosystem on earth, from the polar regions to the tropics, whether on land or in the oceans, has been shown to contain residues or traces of organic and inorganic pollutants of anthropogenic origin.

Published
2011

16. Limulus striated muscle provides an unusual model for muscle contraction

Author

Mm, Dewey, Brink P, Colflesh DE, Bruce Gaylinn, Sf, Fan, and Anapol F

Subjects
Glycerol, Sarcomeres, Fourier Analysis, Myofibrils, Muscles, Horseshoe Crabs, Animals, In Vitro Techniques, Cytoskeleton, Muscle Contraction
Abstract

Although nearly two decades have passed since de Villafranca (1961) described A-band shortening, controversy persists. Here we will review the data which has been amassed since de Villafranca 's description. We will conclude that A-bands and thick filaments shorten during sarcomere shortening in Limulus striated muscle. Further we will suggest that two machines operate in this muscle: a tension generating sliding filament system and a tension generating thick filament shortening system. Also we will suggest a mechanism of force generation of the filament shortening system and provide evidence for a cycling bridge mechanism for this muscle.

Published
1984

19. The SuperCDMS Experiment

Author

Schnee, Richard W., Akerib, D. S., Attisha, M. J., Bailey, C. N., Baudis, L., Bauer, Daniel A., Brink, P. L., Brusov, P. P., Bunker, R., Cabrera, B., Caldwell, David O., Chang, C. L., Cooley, J., Crisler, M. B., Cushman, P., Denes, P., Dragowsky, M. R., Duong, L., Filippini, J., Gaitskell, R. J., Golwala, S. R., Grant, D. R., Hennings-Yeomans, R., Holmgren, D., Huber, M. E., Irwin, K., Lu, A., Mahapatra, R., Meunier, P., Mirabolfathi, N., Nelson, H., Ogburn, R. W., Ramberg, E., Reisetter, A., Tarek Saab, Sadoulet, B., Sander, J., Seitz, D. N., Serfass, B., Sundqvist, K. M., Thompson, J-P F., Yellin, S., Yoo, J., and Young, B. A.

24. Progress of CDMS-II at the Soudan Mine

Author

R W Ogburn, Iv, Brink, P. L., Cooley, J., Cabrera, B., Chang, C. L., Akerib, D. S., Bailey, C. N., Brusov, P. P., Dragowsky, M. R., Driscoll, Donald D., Grant, D. R., Hennings-Yeomans, R., Kamat, S., Perera, T. A., Schnee, R. W., Wang, G., Attisha, M. J., Gaitskell, R. J., Thompson, J-P F., Baudis, L., Saab, T., Bauer, Daniel A., Crisler, M. B., Donald Holmgren, Ramberg, E., Yoo, J., Bunker, R., Caldwell, David O., Ferril, R., Mahapatra, R., Nelson, H., Nelson, R., Sander, J., Savage, Christopher, Yellin, S., Cushman, P., Duong, L., Reisetter, A., Ross, R., Sadoulet, B., Armel-Funkhouser, M. S., Daal, M., Filippini, J., Lu, A., Mandic, V., Meunier, P., Mirabolfathi, N., Seitz, D. N., Serfass, B., Sundqvist, K. M., Huber, M. E., Martinis, J. M., and Young, B. A.

25. A statement of intent on the formation of the NCRP on Cardiovascular and Metabolic Disease: A new initiative to fight heart disease, stroke, diabetes and obesity in South Africa

Author

Mayosi, B., Bryer, A., Lambert, V., Levitt, N., Timothy David Noakes, Ntsekhe, M., Opie, L., Rayner, B., Zilla, P., Abrahams, Z., Abram, M., Bhagwandin, N., Bradshaw, D., Dhansay, A., Mbewu, A., Madela-Mntla, N., Parker, W. -A, Sifunda, S., Skepu, A., Steyn, N., Brown, S., Mollentze, W., Brink, P., Doubell, A., Hough, S., Huisamen, B., Lochner, A., Moolman-Smook, J., Reuter, H., Green-Thompson, W., Horrocks, J., Manga, P., Norris, S., Norton, G., Raal, D., Sliwa, K., Woodiwiss, A., Mntla, P., Motala, A., Naidoo, D., Seedat, Y., Ntutela, S., Puoane, T., and Schwartz, P.

26. Limits on the WIMP nucleon cross-section from the Cryogenic Dark Matter Search

Author

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

29. Effects of chronic low concentrations of pesticides chlorpyrifos and atrazine in indoor freshwater micro-cosms

Author

Den Brink, P. J., Ellen van Donk, Gylstra, R., Crum, S. J. H., and Brock, T. C. M.

Subjects
Aquatic Ecology and Water Quality Management, plant protection, gewasbescherming, pesticide residues, Winand Staring Centre for Integrated Land, Soil and Water Research, water, chemicals, persistentie, pesticidenresiduen, water quality, kanalen, ecotoxicology, oppervlaktewater, waterlopen, Staring Centrum, chemicaliën, pesticiden, water pollution, WIMEK, ecotoxicologie, surface water, toxicologie, persistence, pesticides, waterkwaliteit, Aquatische Ecologie en Waterkwaliteitsbeheer, streams, rivers, canals, rivieren, bioaccumulation, waterverontreiniging, bioaccumulatie, toxicology
Abstract

Standards for pesticide concentrations in water are based on the laboratory toxicity of the most susceptible standard test organisms (algae, crustaceans or fish). Field studies have shown that the standards for the insecticide chlorpyrifos and the herbicide atrazine will protect aquatic ecosystems at both species and community levels. This study was aimed at evaluating the chronic effects of the standards for chlorpyrifos and atrazine in experimental freshwater model ecosystems. It is concluded that standards based on acute exposure are not simply transferable to chronic exposure.

31. First measurements of SuperCDMS SNOLAB 100 mm diameter germanium dark matter detectors with interleaved charge and phonon channels

Author

Chagani, H., Bauer, D. A., Brandt, D., Brink, P. L., Bunker, R., Cabrera, B., Cherry, M., Codoreanu, G. A., Do Couto E Silva, E., Cushman, P., Godfrey, G. L., Hall, J., Hansen, S., Hasi, J., Kelsey, M., Kennedy, A., Kenney, C. J., Leman, S. W., Mandic, V., Mirabolfathi, N., Monin, S., Nagasawa, D., Novak, L., Partridge, R., Phenicie, C., Page, K., Pyle, M., Radpour, R., Rau, W., Resch, R., Sadoulet, B., Seitz, D. N., Serfass, B., Shank, B., Strandberg, D., Tomada, A., Anthony Villano, Yen, J., Young, B. A., and Zhang, J.

32. Reforming environmentally harmful subsidies

Author

Valsecchi, C., Ten Brink, P., Fergusson, M., Bassi, S., Skinner, I., Pallemaerts, M., Best, A., Blobel, D., Berglund, M., Markandya, A., Sgobbi, A., Longo, C., Frans Oosterhuis, Institute for Environmental Studies, and Environmental Economics

34. Search for annual modulation in low-energy CDMS-II data

Author

Ahmed, Z., Akerib, D. S., Anderson, A. J., Arrenberg, S., Bailey, C. N., Balakishiyeva, D., Baudis, L., Bauer, D. A., Brink, P. L., Bruch, T., Bunker, R., Cabrera, B., Caldwell, D. O., Cooley, J., Cushman, P., Daal, M., Dejongh, F., Di Stefano, P. C. F., Dragowsky, M. R., Fallows, S., Figueroa-Feliciano, E., Filippini, J., Fox, J., Fritts, M., Golwala, S. R., Hall, J., Hertel, S. A., Hofer, T., Donald Holmgren, Hsu, L., Huber, M. E., Kamaev, O., Kiveni, M., Kos, M., Leman, S. W., Liu, S., Mahapatra, R., Mandic, V., Mccarthy, K. A., Mirabolfathi, N., Moore, D. C., Nelson, H., Ogburn, R. W., Phipps, A., Prasad, K., Pyle, M., Qiu, X., Rau, W., Reisetter, A., Ricci, Y., Saab, T., Sadoulet, B., Sander, J., Schnee, R. W., Seitz, D., Serfass, B., Speller, D., Sundqvist, K. M., Tarka, M., Thakur, R. B., Villano, A. N., Welliver, B., Yellin, S., Yoo, J., Young, B. A., and Zhang, J.

35. Generation of two human induced pluripotent stem cell (hiPSC) lines from a long QT syndrome South African founder population

Author

Peter J. Schwartz, Enza Maria Valente, Lia Crotti, Massimiliano Gnecchi, Federica Pisano, Manuela Mura, Marina Boni, Federica Calabrò, Monia Ginevrino, Manuela Stefanello, Paul A. Brink, Mura, M, Pisano, F, Stefanello, M, Ginevrino, M, Boni, M, Calabrò, F, Crotti, L, Valente, E, Schwartz, P, Brink, P, and Gnecchi, M

Subjects
0301 basic medicine, Long QT syndrome, Population, Induced Pluripotent Stem Cells, BIO/18 - GENETICA, Biology, QT interval, 03 medical and health sciences, South Africa, 0302 clinical medicine, Mutation Carrier, BIO/09 - FISIOLOGIA, medicine, Humans, Induced pluripotent stem cell, education, lcsh:QH301-705.5, Adaptor Proteins, Signal Transducing, Skin, Genetics, education.field_of_study, Reverse Transcriptase Polymerase Chain Reaction, Cell Biology, General Medicine, MED/11 - MALATTIE DELL'APPARATO CARDIOVASCOLARE, medicine.disease, Phenotype, Immunohistochemistry, Heart Arrest, Long QT Syndrome, 030104 developmental biology, lcsh:Biology (General), Karyotyping, Mutation (genetic algorithm), Mutation, human induced pluripotent stem cell, long qt syndrome, South African founder population, 030217 neurology & neurosurgery, Developmental Biology, Founder effect
Abstract

We generated PSMi001-A and PSMi008-A hiPSC lines from two individuals belonging to a South African (SA) founder population in which the malignant KCNQ1-A341V mutation cosegregates with the Long QT Syndrome (LQTS) phenotype. PSMi001-A was derived from an asymptomatic KCNQ1-A341V mutation carrier, whereas PSMi008-A was derived from a healthy non-mutation carrier, heterozygous for the minor variant rs16847548 on the NOS1AP gene, associated with QT prolongation in the general population, and with a greater risk for cardiac arrest in the affected members of the SA founder population. The hiPSCs, generated using the Yamanaka's retroviruses, display pluripotent stem cell features and trilineage differentiation potential.

Published
2019

36. Autonomic Control of Heart Rate and QT Interval Variability Influences Arrhythmic Risk in Long QT Syndrome Type 1

Author

Giulia Girardengo, Alfred L. George, Lia Crotti, Alberto Porta, Althea Goosen, Paul A. Brink, Peter J. Schwartz, Vlasta Bari, Porta, A, Girardengo, G, Bari, V, George, A, Brink, P, Goosen, A, Crotti, L, and Schwartz, P

Subjects
Adult, congenital, hereditary, and neonatal diseases and abnormalities, medicine.medical_specialty, Sympathetic Nervous System, Romano-Ward Syndrome, Long QT syndrome, Adrenergic beta-Antagonists, QT interval, Article, Electrocardiography, Internal medicine, Heart rate, medicine, Humans, Heart rate variability, cardiovascular diseases, beta-blocker therapy, cardiovascular control, QT variability, medicine.diagnostic_test, business.industry, autonomic nervous system, Case-control study, heart rate variability, Adrenergic beta-Antagonist, Vagus Nerve, MED/11 - MALATTIE DELL'APPARATO CARDIOVASCOLARE, medicine.disease, Circadian Rhythm, Romano–Ward syndrome, Autonomic nervous system, Case-Control Studies, KCNQ1 Potassium Channel, Cardiology, Case-Control Studie, business, Cardiology and Cardiovascular Medicine, Qt Variability, Autonomic Nervous System, Beta-blocker Therapy, Cardiovascular Control, Heart Rate Variability, Human
Abstract

BACKGROUND: A puzzling feature of the long QT syndrome (LQTS) is that family members carrying the same mutation often have divergent symptoms and clinical outcomes. OBJECTIVES: This study tested the hypothesis that vagal and sympathetic control, as assessed by spectral analysis of spontaneous beat-to-beat variability of RR and QT intervals from standard 24-h electrocardiogram Holter recordings, could modulate the severity of LQTS type 1 (LQT1) in 46 members of a South-African LQT1 founder population carrying the clinically severe KCNQ1 A341V mutation. METHODS: Nonmutation carriers (NMCs) (n= 14) were compared with mutation carriers (MCs) (n= 32), 22 with and 10without major symptoms. We assessed the effect of circadian rhythm and beta-blocker therapy over traditional timeand frequency domain RR and QT variability indexes. RESULTS: The asymptomatic MCs differed significantly from the symptomatic MCs and from NMCs in less vagal control of heart rate and more reactive sympathetic modulation of the QT interval, particularly during daytime when arrhythmia risk for patients with LQT1 is greatest. CONCLUSIONS: The present data identified an additional factor contributing to the differential arrhythmic risk amongpatients with LQT1 carrying the same mutation. A healthy autonomic control confers a high risk, whereas patients withhigher sympathetic control of the QT interval and reduced vagal control of heart rate are at lower risk. This differential "autonomic make-up," likely under genetic control, will allow refinement of risk stratification within families with LQTS, leading to more targeted management.

Published
2015
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37. NOS1AP Is a Genetic Modifier of the Long-QT Syndrome

Author

Peter J. Schwartz, Paul A. Brink, Roberto Insolia, Maria Cristina Monti, Lia Crotti, Althea Goosen, David A. Greenberg, Anna L. Peljto, Alfred L. George, Crotti, L, Monti, M, Insolia, R, Peljto, A, Goosen, A, Brink, P, Greenberg, D, Schwartz, P, and George, A

Subjects
Genetic Markers, Male, medicine.medical_specialty, Long QT syndrome, Population, Sudden death, QT interval, Article, Sudden cardiac death, Death, Sudden, Risk Factors, Physiology (medical), Internal medicine, medicine, Humans, education, Adaptor Proteins, Signal Transducing, Genetic association, Genetics, education.field_of_study, long qt syndrome, genetic modifier, NOS1AP, Genetic heterogeneity, business.industry, Genetic Variation, Arrhythmias, Cardiac, MED/11 - MALATTIE DELL'APPARATO CARDIOVASCOLARE, medicine.disease, Long QT Syndrome, Mutation, SECS-S/01 - STATISTICA, Mutation (genetic algorithm), Cardiology, Female, Cardiology and Cardiovascular Medicine, business
Abstract

Background— In congenital long-QT syndrome (LQTS), a genetically heterogeneous disorder that predisposes to sudden cardiac death, genetic factors other than the primary mutation may modify the probability of life-threatening events. Recent evidence indicates that common variants in NOS1AP are associated with the QT-interval duration in the general population. Methods and Results— We tested the hypothesis that common variants in NOS1AP modify the risk of clinical manifestations and the degree of QT-interval prolongation in a South African LQTS population (500 subjects, 205 mutation carriers) segregating a founder mutation in KCNQ1 (A341V) using a family-based association analysis. NOS1AP variants were significantly associated with the occurrence of symptoms (rs4657139, P =0.019; rs16847548, P =0.003), with clinical severity, as manifested by a greater probability for cardiac arrest and sudden death (rs4657139, P =0.028; rs16847548, P =0.014), and with greater likelihood of having a QT interval in the top 40% of values among all mutation carriers (rs4657139, P =0.03; rs16847548, P =0.03). Conclusions— These findings indicate that NOS1AP , a gene first identified as affecting the QTc interval in a general population, also influences sudden death risk in subjects with LQTS. The association of NOS1AP genetic variants with risk for life-threatening arrhythmias suggests that this gene is a genetic modifier of LQTS, and this knowledge may be clinically useful for risk stratification for patients with this disease, after validation in other LQTS populations.

Published
2009

38. Time, frequency and information domain analysis of heart period and QT variability in asymptomatic long QT syndrome type 2 patients

Author

Giulia Girardengo, Vlasta Bari, Alberto Porta, Lia Crotti, Peter J. Schwartz, Beatrice De Maria, Andrea Marchi, Paul A. Brink, Bari, V, Girardengo, G, Marchi, A, De Maria, B, Brink, P, Crotti, L, Schwartz, P, and Porta, A

Subjects
Adult, Male, congenital, hereditary, and neonatal diseases and abnormalities, medicine.medical_specialty, Long QT syndrome, Signal-To-Noise Ratio, Lower risk, Polymorphism, Single Nucleotide, QT interval, Asymptomatic, QT interval variability, Complexity index, Electrocardiography, Internal medicine, long QT syndrome, medicine, Electronic engineering, Humans, Circadian rhythm, medicine.diagnostic_test, business.industry, Heart, MED/11 - MALATTIE DELL'APPARATO CARDIOVASCOLARE, Middle Aged, medicine.disease, Circadian Rhythm, Time–frequency analysis, long QT syndrome type 2, Case-Control Studies, Cardiology, Female, medicine.symptom, business
Abstract

This study was designed to characterize in time, frequency and information domains heart period (HP) and QT interval variabilities in asymptomatic (ASYMP) long QT syndrome type 2 (LQT2) subjects. HP, approximated as the temporal distance between two consecutive R-wave peaks, and QT, approximated as the temporal distance between the R-wave peak and the T-wave offset, were automatically derived from 24h Holter recordings in 10 ASYMP LQT2 patients and 13 healthy non mutation carriers (NMC) subjects. All analyses were carried out during DAY (from 2 to 6 PM) and NIGHT (from 12 to 4 AM). Mean, variance, spectral power and complexity indices at short, medium and long time scales were assessed over HP and QT beat-to-beat series. Circadian rhythmicity was evident in both NMC and ASYMP LQT2 but ASYMP LQT2 subjects were characterized by higher HP, QT interval and HP variability during both DAY and NIGHT. In addition, multiscale complexity analysis was able to differentiate the groups by showing a higher HP complexity and a lower QT complexity at long time scales in ASYMP LQT2 during DAY. ASYMP LQT2 exhibited a different autonomic control compared to NMC and such a differentiation could be protective and assure them a lower risk profile.

Published
2015

39. AKAP9 is a genetic modifier of congenital long-QT syndrome type 1

Author

Althea Goosen, Peter J. Schwartz, Lia Crotti, Lize van der Merwe, Carin P. de Villiers, Johanna C. Moolman-Smook, Corfield Va, Paul A. Brink, Alfred L. George, de Villiers, C, van der Merwe, L, Crotti, L, Goosen, A, George, A, Schwartz, P, Brink, P, Moolman- Smook, J, and Corfield, V

Subjects
Adult, Male, medicine.medical_specialty, Heterozygote, Adolescent, Genotype, Long QT syndrome, Romano-Ward Syndrome, DNA Mutational Analysis, Akap9, Kcnq1, Arrhythmia, Long Qt Syndrome, A Kinase Anchor Proteins, BIO/18 - GENETICA, Biology, arrhythmia, Polymorphism, Single Nucleotide, Severity of Illness Index, Article, Sudden cardiac death, Variable Expression, South Africa, Young Adult, Internal medicine, Severity of illness, Genetics, medicine, Leukocytes, Humans, Genetic Predisposition to Disease, Allele, Genetics (clinical), Alleles, KCNQ1, Models, Genetic, Cardiac arrhythmia, Heterozygote advantage, MED/11 - MALATTIE DELL'APPARATO CARDIOVASCOLARE, Middle Aged, medicine.disease, Founder Effect, long-QT syndrome, Romano–Ward syndrome, Cytoskeletal Proteins, AKAP9, Phenotype, Mutation, Cardiology, Female, Cardiology and Cardiovascular Medicine
Abstract

Background— Long-QT syndrome (LQTS), a cardiac arrhythmia disorder with variable phenotype, often results in devastating outcomes, including sudden cardiac death. Variable expression, independently from the primary disease-causing mutation, can partly be explained by genetic modifiers. This study investigates variants in a known LQTS-causative gene, AKAP9 , for potential LQTS-type 1–modifying effects. Methods and Results— Members of a South African LQTS-type 1 founder population (181 noncarriers and 168 mutation carriers) carrying the identical-by-descent KCNQ1 p.Ala341Val (A341V) mutation were evaluated for modifying effects of AKAP9 variants on heart rate–corrected QT interval (QTc), cardiac events, and disease severity. Tag single nucleotide polymorphisms in AKAP9 rs11772585, rs7808587, rs2282972, and rs2961024 (order, 5′-3′positive strand) were genotyped. Associations between phenotypic traits and alleles, genotypes, and haplotypes were statistically assessed, adjusting for the degree of relatedness and confounding variables. The rs2961024 GG genotype, always represented by CGCG haplotype homozygotes, revealed an age-dependent heart rate–corrected QT interval increase (1% per additional 10 years) irrespective of A341V mutation status ( P =0.006). The rs11772585 T allele, found uniquely in the TACT haplotype, more than doubled (218%) the risk of cardiac events ( P =0.002) in the presence of A341V; additionally, it increased disease severity ( P =0.025). The rs7808587 GG genotype was associated with a 74% increase in cardiac event risk ( P =0.046), whereas the rs2282972 T allele, predominantly represented by the CATT haplotype, decreased risk by 53% ( P =0.001). Conclusions— AKAP9 has been identified as an LQTS-type 1–modifying gene. Variants investigated altered heart rate–corrected QT interval irrespective of mutation status, as well as cardiac event risk, and disease severity, in mutation carriers.

Published
2014

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