Physical Sciences and Mathematics | Open Access Articles

Optimization Of Detergent-Mediated Reconstitution Of Influenza A M2 Protein Into Proteoliposomes, Catherine Hirshfeld Crouch, Margaret H. Bost , '17, Tae H. Kim , '14, Bryan M. Green , '16, Douglas Stuart Arbuckle , '17, Carl H. Grossman, Kathleen P. Howard

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We report the optimization of detergent-mediated reconstitution of an integral membrane-bound protein, full-length influenza M2 protein, by direct insertion into detergent-saturated liposomes. Detergent-mediated reconstitution is an important method for preparing proteoliposomes for studying membrane proteins, and must be optimized for each combination of protein and membrane constituents used. The purpose of the reconstitution was to prepare samples for site-directed spin-labeling electron paramagnetic resonance (SDSL-EPR) studies. Our goals in optimizing the protocol were to minimize the amount of detergent used, reduce overall proteoliposome preparation time, and confirm the removal of all detergent. The liposomes were comprised of (1-palmitoyl-2-oleyl-sn-glycero-phosphocholine (POPC) and 1-palmitoyl-2-oleyl-sn-glycero-3-[phospho-rac-(1-glycerol)] …

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The Kelt Follow-Up Network And Transit False-Positive Catalog: Pre-Vetted False Positives For Tess, K. A. Collins, K. I. Collins, J. Pepper, J. Labadie-Bartz, K. G. Stassun, B. S. Gaudi, D. Bayliss, J. Bento, K. D. Colón, D. Feliz, D. James, M. C. Johnson, R. B. Kuhn, M. B. Lund, M. T. Penny, J. E. Rodriguez, R. J. Siverd, D. J. Stevens, X. Yao, G. Zhou, M. Akshay, G. F. Aldi, C. Ashcraft, S. Awiphan, Ö. Baştürk, D. Baker, T. G. Beatty, P. Benni, P. Berlind, G. B. Berriman, Z. Berta-Thompson, A. Bieryla, V. Bozza, S. C. Novati, M. L. Calkins, J. M. Cann, D. R. Ciardi, W. D. Cochran, David H. Cohen, D. Conti, J. R. Crepp, I. A. Curtis, G. D'Ago, K. A. Diazeguigure, C. D. Dressing, F. Dubois, E. Ellington, T. G. Ellis, G. A. Esquerdo, P. Evans, A. Friedli, A. Fukui, B. J. Fulton, E. J. Gonzales, J. C. Good, J. Gregorio, T. Gumusayak, D. A. Hancock, C. K. Harada, R. Hart, E. G. Hintz, H. Jang-Condell, E. J. Jeffery, Eric L.N. Jensen, E. Jofré, M. D. Joner, A. Kar, D. H. Kasper, B. Keten, J. F. Kielkopf, S. Komonjinda, C. Kotnik, D. W. Latham, J. Leuquire, T. R. Lewis, L. Logie, S. J. Lowther, P. J. Macqueen, T. J. Martin, D. Mawet, K. K. Mcleod, G. Murawski, N. Narita, J. Nordhausen, T. E. Oberst, C. Odden, P. A. Panka, R. Petrucci, P. Plavchan, S. N. Quinn, S. Rau, P. A. Reed, H. Relles, J. P. Renaud, G. Scarpetta, R. L. Sorber, A. D. Spencer, M. Spencer, D. C. Stephens, C. Stockdale, T.-G. Tan, M. Trueblood, P. Trueblood, S. Vanaverbeke, S. Villanueva Jr., E. M. Warner, M. L. West, S. Yalçınkaya, R. Yeigh, R. Zambelli

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The Kilodegree Extremely Little Telescope (KELT) project has been conducting a photometric survey of transiting planets orbiting bright stars for over 10 years. The KELT images have a pixel scale of ~23'' pixel⁻¹—very similar to that of NASA's Transiting Exoplanet Survey Satellite (TESS)—as well as a large point-spread function, and the KELT reduction pipeline uses a weighted photometric aperture with radius 3'. At this angular scale, multiple stars are typically blended in the photometric apertures. In order to identify false positives and confirm transiting exoplanets, we have assembled a follow-up network (KELT-FUN) to conduct imaging with spatial resolution, cadence, and …

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Cosmological Implications Of Ultralight Axionlike Fields, V. Poulin, Tristan L. Smith, D. Grin, R. Karwal, M. Kamionkowski

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Cosmological observations are used to test for imprints of an ultralight axionlike field (ULA), with a range of potentials V(ϕ)∝[1−cos(ϕ/f)]ⁿ set by the axion-field value ϕ and decay constant f. Scalar field dynamics dictate that the field is initially frozen and then begins to oscillate around its minimum when the Hubble parameter drops below some critical value. For n=1, once dynamical, the axion energy density dilutes as matter; for n=2 it dilutes as radiation and for n=3 it dilutes faster than radiation. Both the homogeneous evolution of the ULA and the dynamics of its linear perturbations are included, using an …

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Brownian Dynamics Of Particles “Dressed” By Chiral Director Configurations In Lyotropic Chromonic Liquid Crystals, A. Martinez, Peter J. Collings, A. G. Yodh

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We study Brownian dynamics of colloidal spheres, with planar anchoring conditions, suspended in the nematic phase of the lyotropic chromonic liquid crystal disodium chromoglycate (DSCG). Unlike typical liquid crystals, the unusually small twist elastic modulus of DSCG permits two energetically distinct helical distortions (twisted tails) of the nematic director to “dress” the suspended spheres. Video microscopy is used to characterize the helical distortions versus particle size and to measure particle mean-square displacements. Diffusion coefficients parallel and perpendicular to the far-field director, and their anisotropy ratio, are different for the two twisted tail configurations. Moreover, the crossover from subdiffusive to diffusive …

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Multiple Stellar Flybys Sculpting The Circumstellar Architecture In Rw Aurigae, J. E. Rodriguez, R. Loomis, S. Cabrit, T. H. Haworth, S. Facchini, C. Dougados, R. A. Booth, Eric L.N. Jensen, C. J. Clarke, K. G. Stassun, W. R. F. Dent, J. Pety

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We present high-resolution ALMA Band 6 and 7 observations of the tidally disrupted protoplanetary disks of the RW Aurigae binary. Our observations reveal tidal streams in addition to the previously observed tidal arm around RW Aur A. The observed configuration of tidal streams surrounding RW Aur A and B is incompatible with a single star–disk tidal encounter, suggesting that the RW Aurigae system has undergone multiple flyby interactions. We also resolve the circumstellar disks around RW Aur A and B, with CO radii of 58 au and 38 au consistent with tidal truncation, and 2.5 times smaller dust emission radii. …

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Sources Of Student Engagement In Introductory Physics For Life Sciences, Benjamin D. Geller , '01, C. Turpen, Catherine Hirshfeld Crouch

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We explore the sources of student engagement with curricular content in an Introductory Physics for Life Science (IPLS) course at Swarthmore College. Do IPLS students find some life-science contexts more interesting than others, and, if so, what are the sources of these differences? We draw on three sources of student data to answer this question: (1) quantitative survey data illustrating how interested students were in particular contexts from the curriculum, (2) qualitative survey data in which students describe the source of their interest in these particular contexts, and (3) interview data in which students reflect on the contexts that were …

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Magnetothermodynamics: Measurements Of The Thermodynamic Properties In A Relaxed Magnetohydrodynamic Plasma, M. Kaur, Luke J. Barbano , '18, Emma M. Suen-Lewis , '18, Jaron E. Shrock , '18, A. D. Light, D. A. Schaffner, Michael R. Brown, S. Woodruff, T. Meyer

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We have explored the thermodynamics of compressed magnetized plasmas in laboratory experiments and we call these studies ‘magnetothermodynamics’. The experiments are carried out in the Swarthmore Spheromak eXperiment device. In this device, a magnetized plasma source is located at one end and at the other end, a closed conducting can is installed. We generate parcels of magnetized plasma and observe their compression against the end wall of the conducting cylinder. The plasma parameters such as plasma density, temperature and magnetic field are measured during compression using HeNe laser interferometry, ion Doppler spectroscopy and a linear dot{B} probe array, respectively. To …

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Kelt-21b: A Hot Jupiter Transiting The Rapidly Rotating Metal-Poor Late-A Primary Of A Likely Hierarchical Triple System, M. C. Johnson, J. E. Rodriguez, G. Zhou, E. J. Gonzales, P. A. Cargile, J. R. Crepp, K. Penev, K. G. Stassun, B. S. Gaudi, K. D. Colón, D. J. Stevens, K. G. Strassmeier, I. Ilyin, K. A. Collins, J. F. Kielkopf, T. E. Oberst, L. Maritch, P. A. Reed, J. Gregorio, V. Bozza, S. Calchi Novati, G. D'Ago, G. Scarpetta, R. Zambelli, D. W. Latham, A. Bieryla, W. D. Cochran, M. Endl, J. Tayar, A. Serenelli, V. S. Aguirre, S. P. Clarke, M. Martinez, M. Spencer, J. Trump, M. D. Joner, A. G. Bugg, E. G. Hintz, D. C. Stephens, A. Arredondo, A. Benzaid, S. Yazdi, K. K. Mcleod, Eric L.N. Jensen, D. A. Hancock, R. L. Sorber, D. H. Kasper, H. Jang-Condell, T. G. Beatty, T. Carroll, J. Eastman, D. James, R. B. Kuhn, J. Labadie-Bartz, M. B. Lund, M. Mallonn, J. Pepper, R. J. Siverd, X. Yao, David H. Cohen, I. A. Curtis, D. L. Depoy, B. J. Fulton, M. T. Penny, H. Relles, C. Stockdale, T.-G. Tan, S. Villanueva Jr.

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We present the discovery of KELT-21b, a hot Jupiter transiting the V = 10.5 A8V star HD 332124. The planet has an orbital period of P = 3.6127647 ± 0.0000033 days and a radius of 1.586 (+0.039)/(-0.040) R_J. We set an upper limit on the planetary mass of M_P < 3.91 M_J at 3σ confidence. We confirmed the planetary nature of the transiting companion using this mass limit and Doppler tomographic observations to verify that the companion transits HD 332124. These data also demonstrate that the planetary orbit is well-aligned with the stellar spin, with a sky-projected …

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Measuring The Equations Of State In A Relaxed Magnetohydrodynamic Plasma, M. Kaur, Luke J. Barbano , '18, Emma M. Suen-Lewis , '18, Jaron E. Shrock , '18, A. D. Light, Michael R. Brown

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We report measurements of the equations of state of a fully relaxed magnetohydrodynamic (MHD) laboratory plasma. Parcels of magnetized plasma, called Taylor states, are formed in a coaxial magnetized plasma gun, and are allowed to relax and drift into a closed flux conserving volume. Density, ion temperature, and magnetic field are measured as a function of time as the Taylor states compress and heat. The theoretically predicted MHD and double adiabatic equations of state are compared to experimental measurements. We find that the MHD equation of state is inconsistent with our data.

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Temperature And Lifetime Measurements In The Ssx Wind Tunnel, M. Kaur, Kaitlin D. Gelber , '20, A. D. Light, Michael R. Brown

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We describe ion and electron temperature measurements in the Swarthmore Spheromak Experiment (SSX) MHD wind tunnel with the goal of understanding limitations on the lifetime of our Taylor-state plasma. A simple model based on the equilibrium eigenvalue and Spitzer resistivity predicted the lifetime satisfactorily during the first phase of the plasma evolution. We measured an average Tₑ along a chord by taking the ratio of the CIII97.7 nm to CIV155 nm line intensities using a vacuum ultraviolet (VUV) monochromator. We also recorded local measurements of Tₑ and nₑ using a double Langmuir probe in order to inform our interpretation of …

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Kelt-19ab: A P ∼ 4.6-Day Hot Jupiter Transiting A Likely Am Star With A Distant Stellar Companion, R. J. Siverd, K. A. Collins, G. Zhou, S. N. Quinn, B. S. Gaudi, K. G. Stassun, M. C. Johnson, A. Bieryla, D. W. Latham, D. R. Ciardi, J. E. Rodriguez, K. Penev, M. Pinsonneault, J. Pepper, J. D. Eastman, H. Relles, J. F. Kielkopf, J. Gregorio, T. E. Oberst, G. F. Aldi, G. A. Esquerdo, M. L. Calkins, P. Berlind, C. D. Dressing, R. Patel, D. J. Stevens, T. G. Beatty, M. B. Lund, J. Labadie-Bartz, R. B. Kuhn, K. D. Colón, D. James, X. Yao, J. A. Johnson, J. T. Wright, N. Mccrady, R. A. Wittenmyer, S. A. Johnson, D. H. Sliski, Eric L.N. Jensen, David H. Cohen, K. K. Mcleod, M. T. Penny, M. D. Joner, D. C. Stephens, S. Villanueva Jr., R. Zambelli, C. Stockdale, P. Evans, T.-G. Tan, I. A. Curtis, P. A. Reed, M. Trueblood, P. Trueblood

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We present the discovery of the giant planet KELT-19Ab, which transits the moderately bright (V ~ 9.9) A8V star TYC 764-1494-1 with an orbital period of 4.61 days. We confirm the planetary nature of the companion via a combination of radial velocities, which limit the mass to ≲ 4.1 M_J (3σ), and a clear Doppler tomography signal, which indicates a retrograde projected spin–orbit misalignment of λ = -179.7 (+3.7)/(-3.8) degrees. Global modeling indicates that the T_eff = 7500 ± 110 K host star has M_* = 1.62 (+0.25)/(-0.20) M_⊙ and R_* = …

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Full-Text Articles in Physical Sciences and Mathematics

Optimization Of Detergent-Mediated Reconstitution Of Influenza A M2 Protein Into Proteoliposomes, Catherine Hirshfeld Crouch, Margaret H. Bost , '17, Tae H. Kim , '14, Bryan M. Green , '16, Douglas Stuart Arbuckle , '17, Carl H. Grossman, Kathleen P. Howard

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works

Cosmological Implications Of Ultralight Axionlike Fields, V. Poulin, Tristan L. Smith, D. Grin, R. Karwal, M. Kamionkowski

Physics & Astronomy Faculty Works

Brownian Dynamics Of Particles “Dressed” By Chiral Director Configurations In Lyotropic Chromonic Liquid Crystals, A. Martinez, Peter J. Collings, A. G. Yodh

Physics & Astronomy Faculty Works

Multiple Stellar Flybys Sculpting The Circumstellar Architecture In Rw Aurigae, J. E. Rodriguez, R. Loomis, S. Cabrit, T. H. Haworth, S. Facchini, C. Dougados, R. A. Booth, Eric L.N. Jensen, C. J. Clarke, K. G. Stassun, W. R. F. Dent, J. Pety

Physics & Astronomy Faculty Works

Sources Of Student Engagement In Introductory Physics For Life Sciences, Benjamin D. Geller , '01, C. Turpen, Catherine Hirshfeld Crouch

Physics & Astronomy Faculty Works

Magnetothermodynamics: Measurements Of The Thermodynamic Properties In A Relaxed Magnetohydrodynamic Plasma, M. Kaur, Luke J. Barbano , '18, Emma M. Suen-Lewis , '18, Jaron E. Shrock , '18, A. D. Light, D. A. Schaffner, Michael R. Brown, S. Woodruff, T. Meyer

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works

Measuring The Equations Of State In A Relaxed Magnetohydrodynamic Plasma, M. Kaur, Luke J. Barbano , '18, Emma M. Suen-Lewis , '18, Jaron E. Shrock , '18, A. D. Light, Michael R. Brown

Physics & Astronomy Faculty Works

Temperature And Lifetime Measurements In The Ssx Wind Tunnel, M. Kaur, Kaitlin D. Gelber , '20, A. D. Light, Michael R. Brown

Physics & Astronomy Faculty Works

Physics & Astronomy Faculty Works