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2,387 results on '"Cole L"'

1. Host Tropism and Structural Biology of ABC Toxin Complexes

Author

Cole L. Martin, John H. Hill, and Stephen G. Aller

Subjects
ABC toxins, translocase, cryo-EM, host tropism, structural biology, X-ray crystallography, Medicine
Abstract

ABC toxin complexes are a class of protein toxin translocases comprised of a multimeric assembly of protein subunits. Each subunit displays a unique composition, contributing to the formation of a syringe-like nano-machine with natural cargo carrying, targeting, and translocation capabilities. Many of these toxins are insecticidal, drawing increasing interest in agriculture for use as biological pesticides. The A subunit (TcA) is the largest subunit of the complex and contains domains associated with membrane permeation and targeting. The B and C subunits, TcB and TcC, respectively, package into a cocoon-like structure that contains a toxic peptide and are coupled to TcA to form a continuous channel upon final assembly. In this review, we outline the current understanding and gaps in the knowledge pertaining to ABC toxins, highlighting seven published structures of TcAs and how these structures have led to a better understanding of the mechanism of host tropism and toxin translocation. We also highlight similarities and differences between homologues that contribute to variations in host specificity and conformational change. Lastly, we review the biotechnological potential of ABC toxins as both pesticides and cargo-carrying shuttles that enable the transport of peptides into cells.

Published
2024
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2. SpikeInterface, a unified framework for spike sorting

Author

Alessio P Buccino, Cole L Hurwitz, Samuel Garcia, Jeremy Magland, Joshua H Siegle, Roger Hurwitz, and Matthias H Hennig

Subjects
spike sorting, extracellular recordings, open-source software, python, reproducibility, Medicine, Science, Biology (General), QH301-705.5
Abstract

Much development has been directed toward improving the performance and automation of spike sorting. This continuous development, while essential, has contributed to an over-saturation of new, incompatible tools that hinders rigorous benchmarking and complicates reproducible analysis. To address these limitations, we developed SpikeInterface, a Python framework designed to unify preexisting spike sorting technologies into a single codebase and to facilitate straightforward comparison and adoption of different approaches. With a few lines of code, researchers can reproducibly run, compare, and benchmark most modern spike sorting algorithms; pre-process, post-process, and visualize extracellular datasets; validate, curate, and export sorting outputs; and more. In this paper, we provide an overview of SpikeInterface and, with applications to real and simulated datasets, demonstrate how it can be utilized to reduce the burden of manual curation and to more comprehensively benchmark automated spike sorters.

Published
2020
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3. Cancer Chemopreventive Effects of Gum Resin Hydrodistillates on Invasive Urothelial Cell Carcinoma: Report of a Case

Author

Ding Xia MD, Weiwei Lou MD, Kar-Ming Fung MD, PhD, Cole L. Wolley PhD, Mahmoud M. Suhail MD, and Hsueh-Kung Lin PhD

Subjects
Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282
Abstract

A 52-year-old Hispanic male presented with hematuria and was later diagnosed with a large invasive high-grade urothelial cell carcinoma (UCC) of the urinary bladder, but with ambiguous pT1/pT2 staging regarding musclaris propria invasion by UCC. The conventional treatment including radical cystoprostatectomy followed by neoadjuvant chemotherapy with or without radiation therapy was presented. The patient decided to delay the standard therapy until a later stage, but elected to go through transurethral resection of bladder tumor (TURBT) without Bacillus Calmette-Guérin instillation. Following TURBT, the patient started oral Boswellia sacra gum resin (aka frankincense or Ru Xiang in Chinese) hydrodistillates (BSGRH) administration at 3 mL daily with lifestyle changes, and continued this regimen in the last 25 months. Within the first year after diagnosis, the patient experienced 2 recurrences. Recurrent tumors were removed by TURBT alone and both tumors were far smaller than the original one. After the second recurrence, the patient has no detectible cancer in the bladder based on cystoscopy for 14 months and has an intact genitourinary system. His liver and kidney functions are considered to be normal based on blood chemistry tests. This index case suggests that BSGRH may have cancer chemopreventive effects on UCC. The use of Boswellia -derived products in the management of cancer has been well document in other published studies, and boswellic acids have been suggested to be the major component. However, BSGRH contains very little boswellic acids. Demonstration of cancer chemoprevention using BSGRH is one step forward in isolating the key components other than boswellic acids in frankincense. The critical question as to whether these components can simultaneously activate multiple pathways in cancer cells to execute cancer suppression/cytotoxicity or prevention effects remains to be addressed. More studies including identification of key molecules, pharmacokinetics of major compounds, as well as long-term benefits and possible adverse effects will be needed to meet the guidelines of the US Food and Drug Administration for botanical drug development.

Published
2017
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5. Measurement of R=σL/σT and the separated longitudinal and transverse structure functions in the nucleon-resonance region

Author

Liang, Y, Tvaskis, V, Christy, ME, Ahmidouch, A, Armstrong, CS, Arrington, J, Asaturyan, R, Avery, S, Baker, OK, Beck, DH, Blok, HP, Bochna, CW, Boeglin, W, Bosted, P, Bouwhuis, M, Breuer, H, Brown, DS, Bruell, A, Carlini, RD, Cha, J, Chant, NS, Cochran, A, Cole, L, Danagoulian, S, Day, DB, Dunne, J, Dutta, D, Ent, R, Fenker, HC, Fox, B, Gan, L, Gao, H, Garrow, K, Gaskell, D, Gasparian, A, Geesaman, DF, Gilman, R, Guèye, PLJ, Harvey, M, Holt, RJ, Jiang, X, Jones, M, Keppel, CE, Kinney, E, Lorenzon, W, Lung, A, Mack, DJ, Markowitz, P, Martin, JW, McIlhany, K, McKee, D, Meekins, D, Miller, MA, Milner, RG, Mitchell, JH, Mkrtchyan, H, Mueller, BA, Nathan, A, Niculescu, G, Niculescu, I, O'Neill, TG, Papavassiliou, V, Pate, SF, Piercey, RB, Potterveld, D, Ransome, RD, Reinhold, J, Rollinde, E, Rondon, O, Roos, P, Sarty, AJ, Sawafta, R, Schulte, EC, Segbefia, E, Smith, C, Stepanyan, S, Strauch, S, Tadevosyan, V, Tang, L, Tieulent, R, Uzzle, A, Vulcan, WF, Wood, SA, Xiong, F, Yuan, L, Zeier, M, Zihlmann, B, and Ziskin, V

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Nuclear and plasma physics
Abstract

We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range 0.2

Published
2022

9. A modular apparatus for use in high-precision measurements of parity violation in polarized eV neutron transmission`

Author

Schaper, D. C., Auton, C., Barrón-Palos, L., Borrego, M., Chavez, A., Cole, L., Crawford, C. B., Curole, J., Dhahri, H., Dickerson, K. A., Doskow, J., Fox, W., Gervais, M. H., Goodson, B. M., Knickerbocker, K., Jiang, C., King, P. M., Lu, H., Mocko, M., Olivera-Velarde, D., Munoz, J. G. Otero, Penttilä, S. I., Pérez-Martín, A., Snow, W. M., Steffen, K., Vanderwerp, J., and Visser, G.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

We describe a modular apparatus for use in parity-violation measurements in epithermal neutron-nucleus resonances with high instantaneous neutron fluxes at the Manuel Lujan Jr.\ Neutron Scattering Center at Los Alamos National Laboratory. This apparatus is designed to conduct high-precision measurements of the parity-odd transmission asymmetry of longitudinally polarized neutrons through targets containing nuclei with p-wave neutron-nucleus resonances in the 0.1-10 eV energy regime and to accommodate a future search for time reversal violation in polarized neutron transmission through polarized nuclear targets. The apparatus consists of an adjustable neutron and gamma collimation system, a \(^3\)He-$^{4}$He ion chamber neutron flux monitor, two identical cryostats for target cooling, an adiabatic eV-neutron spin flipper, a near-unit efficiency \(^6\)Li-\(^{7}\)Li scintillation detector operated in current mode, a flexible CAEN data acquisition system, and a neutron spin filter based on spin-exchange optical pumping of $^{3}$He gas. We describe the features of the apparatus design devoted to the suppression of systematic errors in parity-odd asymmetry measurements. We describe the configuration of the apparatus used to conduct a precision measurement of parity violation at the 0.7 eV p-wave resonance in $^{139}$La which employs two identical $^{139}$La targets, one to polarize the beam on the p-wave resonance using the weak interaction and one to analyze the polarization., Comment: 43 pages, 23 figures

Published
2020
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10. Scalable Spike Source Localization in Extracellular Recordings using Amortized Variational Inference

Author

Hurwitz, Cole L., Xu, Kai, Srivastava, Akash, Buccino, Alessio P., and Hennig, Matthias H.

Subjects
Quantitative Biology - Neurons and Cognition, Computer Science - Machine Learning
Abstract

Determining the positions of neurons in an extracellular recording is useful for investigating functional properties of the underlying neural circuitry. In this work, we present a Bayesian modelling approach for localizing the source of individual spikes on high-density, microelectrode arrays. To allow for scalable inference, we implement our model as a variational autoencoder and perform amortized variational inference. We evaluate our method on both biophysically realistic simulated and real extracellular datasets, demonstrating that it is more accurate than and can improve spike sorting performance over heuristic localization methods such as center of mass.

Published
2019

14. Development of a Large-Enrollment Course-Based Research Experience in an Undergraduate Organic Chemistry Laboratory: Structure-Function Relationships in Pyrylium Photoredox Catalysts

Author

Cruz, Cole L., Holmberg-Douglas, Natalie, Onuska, Nicholas P. R., McManus, Joshua B., MacKenzie, Ian A., Hutson, Bryant L., Eskew, Nita A., and Nicewicz, David A.

Abstract

Despite the recognized effectiveness of course-based undergraduate research experiences (CUREs), there are few examples of the development of a CURE-based course in a large-enrollment undergraduate organic chemistry laboratory. Herein, we describe the development and implementation of a series of undergraduate laboratory experiments centered around the synthesis and characterization of pyrylium salts in the context of photoredox catalysis. Pre- and post-survey data regarding the CURE features of collaboration, discovery, iteration, and student project ownership also highlight the strengths of the CURE implementation in this large-scale lab course.

Published
2020
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15. I've Been Given COPUS (Classroom Observation Protocol for Undergraduate STEM) Data on My Chemistry Class... Now What?

Author

Reisner, Barbara A., Pate, Cole L., Kinkaid, Melissa M., Paunovic, Daniel M., Pratt, Justin M., Stewart, Joanne L., Raker, Jeffrey R., Bentley, Anne K., Lin, Shirley, and Smith, Sheila R.

Abstract

Classroom observation data using tools such as the Classroom Observation Protocol for Undergraduate STEM (COPUS) are frequently collected in instructional settings for large-scale research studies and program assessment. While COPUS data may be provided to instructors, it is often provided with little or no guidance on how the data can be used to inform teaching practice. This communication is designed to serve as a guide for chemistry instructors to understand the COPUS data from their course, facilitate engagement with the results, and provide strategies for making meaningful changes in response to the data.

Published
2020
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16. Targeted Neural Dynamical Modeling.

Author

Cole L. Hurwitz, Akash Srivastava, Kai Xu, Justin Jude, Matthew G. Perich, Lee E. Miller, and Matthias H. Hennig

Published
2021

17. Host Tropism and Structural Biology of ABC Toxin Complexes.

Author

Martin, Cole L., Hill, John H., and Aller, Stephen G.

Subjects
*BIOPESTICIDES, *VIRAL tropism, *BIOTECHNOLOGY, *X-ray crystallography, *PEPTIDES
Abstract

ABC toxin complexes are a class of protein toxin translocases comprised of a multimeric assembly of protein subunits. Each subunit displays a unique composition, contributing to the formation of a syringe-like nano-machine with natural cargo carrying, targeting, and translocation capabilities. Many of these toxins are insecticidal, drawing increasing interest in agriculture for use as biological pesticides. The A subunit (TcA) is the largest subunit of the complex and contains domains associated with membrane permeation and targeting. The B and C subunits, TcB and TcC, respectively, package into a cocoon-like structure that contains a toxic peptide and are coupled to TcA to form a continuous channel upon final assembly. In this review, we outline the current understanding and gaps in the knowledge pertaining to ABC toxins, highlighting seven published structures of TcAs and how these structures have led to a better understanding of the mechanism of host tropism and toxin translocation. We also highlight similarities and differences between homologues that contribute to variations in host specificity and conformational change. Lastly, we review the biotechnological potential of ABC toxins as both pesticides and cargo-carrying shuttles that enable the transport of peptides into cells. [ABSTRACT FROM AUTHOR]

Published
2024
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19. Safety and tolerability of transcranial magnetic and direct current stimulation in children: Prospective single center evidence from 3.5 million stimulations

Author

Zewdie, E., Ciechanski, P., Kuo, H.C., Giuffre, A., Kahl, C., King, R., Cole, L., Godfrey, H., Seeger, T., Swansburg, R., Damji, O., Rajapakse, T., Hodge, J., Nelson, S., Selby, B., Gan, L., Jadavji, Z., Larson, J.R., MacMaster, F., Yang, J.F., Barlow, K., Gorassini, M., Brunton, K., and Kirton, A.

Published
2020
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23. The experiments with the High Resolution Kaon Spectrometer at JLab Hall C and the new spectroscopy of ${}^{12}_{\Lambda}\text{B}$ hypernuclei

Author

Tang, L., Chen, C., Gogami, T., Kawama, D., Han, Y., Yuan, L., Matsumura, A., Okayasu, Y., Seva, T., Rodriguez, V. M., Baturin, P., Acha, A., Achenbach, P., Ahmidouch, A., Albayrak, I., Androic, D., Asaturyan, A., Asaturyan, R., Ates, O., Badui, R., Baker, O. K., Benmokhtar, F., Boeglin, W., Bono, J., Bosted, P., Brash, E., Carter, P., Carlini, R., Chiba, A., Christy, M. E., Cole, L., Dalton, M. M., Danagoulian, S., Daniel, A., De Leo, R., Dharmawardane, V., Doi, D., Egiyan, K., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Gibson, E. F., Gueye, P., Hashimoto, O., Honda, D., Horn, T., Hu, B., Hungerford, Ed V., Jayalath, C., Jones, M., Johnston, K., Kalantarians, N., Kanda, H., Kaneta, M., Kato, F., Kato, S., Kawai, M., Keppel, C., Khanal, H., Kohl, M., Kramer, L., Lan, K. J., Li, Y., Liyanage, A., Luo, W., Mack, D., Maeda, K., Malace, S., Margaryan, A., Marikyan, G., Markowitz, P., Maruta, T., Maruyama, N., Maxwell, V., Millener, D. J., Miyoshi, T., Mkrtchyan, A., Mkrtchyan, H., Motoba, T., Nagao, S., Nakamura, S. N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M. I., Nunez, A., Nuruzzaman, Nomura, H., Nonaka, K., Ohtani, A., Oyamada, M., Perez, N., Petkovic, T., Pochodzalla, J., Qiu, X., Randeniya, S., Raue, B., Reinhold, J., Rivera, R., Roche, J., Samanta, C., Sato, Y., Sawatzky, B., Segbefia, E. K., Schott, D., Shichijo, A., Simicevic, N., Smith, G., Song, Y., Sumihama, M., Tadevosyan, V., Takahashi, T., Taniya, N., Tsukada, K., Tvaskis, V., Veilleux, M., Vulcan, W., Wells, S., Wesselmann, F. R., Wood, S. A., Yamamoto, T., Yan, C., Ye, Z., Yokota, K., Zhamkochyan, S., and Zhu, L.

Subjects
Nuclear Experiment
Abstract

Since the pioneering experiment, E89-009 studying hypernuclear spectroscopy using the $(e,e^{\prime}K^+)$ reaction was completed, two additional experiments, E01-011 and E05-115, were performed at Jefferson Lab. These later experiments used a modified experimental design, the "tilt method", to dramatically suppress the large electromagnetic background, and allowed for a substantial increase in luminosity. Additionally, a new kaon spectrometer, HKS (E01-011), a new electron spectrometer, HES, and a new splitting magnet were added to produce precision, high-resolution hypernuclear spectroscopy. These two experiments, E01-011 and E05-115, resulted in two new data sets, producing sub-MeV energy resolution in the spectra of ${}^{7}_{\Lambda}\text{He}$, ${}^{12}_{\Lambda}\text{B}$ and ${}^{28}_{\Lambda}\text{Al}$ and ${}^{7}_{\Lambda}\text{He}$, ${}^{10}_{\Lambda}\text{Be}$, ${}^{12}_{\Lambda}\text{B}$ and ${}^{52}_{\Lambda}\text{V}$. All three experiments obtained a ${}^{12}_{\Lambda}\text{B}$, spectrum, which is the most characteristic $p$-shell hypernucleus and is commonly used for calibration. Independent analyses of these different experiments demonstrate excellent consistency and provide the clearest level structure to date of this hypernucleus as produced by the $(e,e^{\prime}K^+)$ reaction. This paper presents details of these experiments, and the extraction and analysis of the observed ${}^{12}_{\Lambda}\text{B}$ spectrum.

Published
2014
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24. Expert assessment of future vulnerability of the global peatland carbon sink

Author

Loisel, J., Gallego-Sala, A. V., Amesbury, M. J., Magnan, G., Anshari, G., Beilman, D. W., Benavides, J. C., Blewett, J., Camill, P., Charman, D. J., Chawchai, S., Hedgpeth, A., Kleinen, T., Korhola, A., Large, D., Mansilla, C. A., Müller, J., van Bellen, S., West, J. B., Yu, Z., Bubier, J. L., Garneau, M., Moore, T., Sannel, A. B. K., Page, S., Väliranta, M., Bechtold, M., Brovkin, V., Cole, L. E. S., Chanton, J. P., Christensen, T. R., Davies, M. A., De Vleeschouwer, F., Finkelstein, S. A., Frolking, S., Gałka, M., Gandois, L., Girkin, N., Harris, L. I., Heinemeyer, A., Hoyt, A. M., Jones, M. C., Joos, F., Juutinen, S., Kaiser, K., Lacourse, T., Lamentowicz, M., Larmola, T., Leifeld, J., Lohila, A., Milner, A. M., Minkkinen, K., Moss, P., Naafs, B. D. A., Nichols, J., O’Donnell, J., Payne, R., Philben, M., Piilo, S., Quillet, A., Ratnayake, A. S., Roland, T. P., Sjögersten, S., Sonnentag, O., Swindles, G. T., Swinnen, W., Talbot, J., Treat, C., Valach, A. C., and Wu, J.

Published
2021
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27. Observation of the Helium 7 Lambda hypernucleus by the (e,e'K+) reaction

Author

Nakamura, S. N., Matsumura, A., Okayasu, Y., Seva, T., Rodriguez, V. M., Baturin, P., Yuan, L., Acha, A., Ahmidouch, A., Androic, D., Asaturyan, A., Asaturyan, R., Baker, O. K., Benmokhtar, F., Bosted, P., Carlini, R., Chen, C., Christy, M., Cole, L., Danagoulian, S., Daniel, A., Dharmawardane, V., Egiyan, K., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gan, L., Gaskell, D., Gasparian, A., Gibson, E. F., Gogami, T., Gueye, P., Han, Y., Hashimoto, O., Hiyama, E., Honda, D., Horn, T., Hu, B., Hungerford, Ed V., Jayalath, C., Jones, M., Johnston, K., Kalantarians, N., Kanda, H., Kaneta, M., Kato, F., Kato, S., Kawama, D., Keppel, C., Lan, K. J., Luo, W., Mack, D., Maeda, K., Malace, S., Margaryan, A., Marikyan, G., Markowitz, P., Maruta, T., Maruyama, N., Miyoshi, T., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Navasardyan, T., Niculescu, G., Niculescu, M. -I., Nomura, H., Nonaka, K., Ohtani, A., Oyamada, M., Perez, N., Petkovic, T., Randeniya, S., Reinhold, J., Roche, J., Sato, Y., Segbefia, E. K., Simicevic, N., Smith, G., Song, Y., Sumihama, M., Tadevosyan, V., Takahashi, T., Tang, L., Tsukada, K., Tvaskis, V., Vulcan, W., Wells, S., Wood, S. A., Yan, C., and Zhamkochyan, S.

Subjects
Nuclear Experiment
Abstract

An experiment with a newly developed high-resolution kaon spectrometer (HKS) and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich hypernucleus, He 7 Lambda, was observed for the first time with the (e,e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The he 7 Lambda binding energy supplies the last missing information of the A=7, T=1 hypernuclear iso-triplet, providing a new input for the charge symmetry breaking (CSB) effect of \Lambda N potential., Comment: 5 pages, 4 figures, submitted to PRL

Published
2012
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28. Cross sections and Rosenbluth separations in 1H(e, e'K+)Lambda up to Q2=2.35 GeV2

Author

Coman, M., Markowitz, P., Aniol, K. A., Baker, K., Boeglin, W. U., Breuer, H., Bydzovsky, P., Camsonne, A., Cha, J., Chang, C. C., Chant, N., Chen, J. -P., Chudakov, E. A., Cisbani, E., Cole, L., Cusanno, F., de Jager, C. W., De Leo, R., Deur, A. P., Dieterich, S., Dohrmann, F., Dutta, D., Ent, R., Filoti, O., Fissum, K., Frullani, S., Garibaldi, F., Gayou, O., Gilman, F., Gomez, J., Gueye, P., Hansen, J. O., Higinbotham, D. W., Hinton, W., Horn, T., Hu, B., Huber, G. M., Iodice, M., Jackson, C., Jiang, X., Jones, M., Kanda, K., Keppel, C., King, P., Klein, F., Kozlov, K., Kramer, K., Kramer, L., Lagamba, L., LeRose, J. J., Liyanage, N., Margaziotis, D. J., Marrone, S., McCormick, K., Michaels, R. W., Mitchell, J., Miyoshi, T., Nanda, S., Palomba, M., Pattichio, V., Perdrisat, C. F., Piasetzky, E., Punjabi, V. A., Raue, B., Reinhold, J., Reitz, B., Roche, R. E., Roos, P., Saha, A., Sarty, A. J., Sato, Y., Sirca, S., Sotona, M., Tang, L., Ueno, H., Ulmer, P. E., Urciuoli, G. M., Uzzle, A., Vacheret, A., Wang, K., Wijesooriya, K., Wojtsekhowski, B., Wood, S., Yaron, I., Zheng, X., and Zhu, L.

Subjects
Nuclear Experiment
Abstract

The kaon electroproduction reaction 1H(e,e'K+)Lambda was studied as a function of the virtual-photon four-momentum, Q2, total energy, W, and momentum transfer, t, for different values of the virtual- photon polarization parameter. Data were taken at electron beam energies ranging from 3.40 to 5.75 GeV. The center of mass cross section was determined for 21 kinematics corresponding to Q2 of 1.90 and 2.35 GeV2 and the longitudinal, sigmaL, and transverse, sigmaT, cross sections were separated using the Rosenbluth technique at fixed W and t. The separated cross sections reveal a flat energy dependence at forward kaon angles not satisfactorily described by existing electroproduction models. Influence of the kaon pole on the cross sections was investigated by adopting an off-shell form factor in the Regge model which better describes the observed energy dependence of sigmaT and sigmaL., Comment: 5 pages, 4 figures. Submitted to Physical Review C, Rapid Communications

Published
2009
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29. Nondestructive Evaluation and Residual Property Assessment of Impacted Nylon/carbon-Fiber Additively Manufactured FFF Components Using Four-Point Bend and Ultrasonic Testing.

Author

Wilkins, Jackson C., Ritter, Cole L., Matalgah, Khaled, and Fleck, T. J.

Subjects
NONDESTRUCTIVE testing, COMPUTED tomography, FIBROUS composites, MANUFACTURING processes, BEND testing
Abstract

Fusion-based material extrusion additive manufacturing, commonly known as fused filament fabrication (FFF), is a layer-by-layer manufacturing process known for creating custom components, specializing in complex geometries, with applications in the aerospace, automotive, medical, as well as many other industries. Due to the critical nature of these industries, it is imperative to understand the relationship between the AM material in question, the nature of the resultant damage, and the impact of these two parameters on the future performance of the component. The purpose of this study is to investigate the relationship between low-velocity impact and the resultant damage in common functional FFF materials and to develop methods of visualizing that damage using ultrasonic nondestructive evaluation. Coupons of a nylon feedstock infused with and without 10% chopped carbon fiber were fabricated using an Essentium HSE printer and impacted at various energies. The extent of the damage was visualized using ultrasonic testing (UT), in which significant internal cracking was observed. Four-point bend testing was utilized to compare behavior of the material prior to impact at a lower impact energy (3J), and a higher impact energy causing visual fracture (7J). X-ray CT was also performed on two samples to validate UT findings. [ABSTRACT FROM AUTHOR]

Published
2024
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31. Probing Quark-Gluon Interactions with Transverse Polarized Scattering

Author

Slifer, K., Rondon, O. A., Aghalaryan, A., Ahmidouch, A., Asaturyan, R., Bloch, F., Boeglin, W., Bosted, P., Carasco, C., Carlini, R., Cha, J., Chen, J. P., Christy, M. E., Cole, L., Coman, L., Crabb, D., Danagoulian, S., Day, D., Dunne, J., Elaasar, M., Ent, R., Fenker, H., Frlez, E., Gaskell, D., Gan, L., Gomez, J., Hu, B., Jourdan, J., Jones, M. K., Keith, C., Keppel, C. E., Khandaker, M., Klein, A., Kramer, L., Liang, Y., Lichtenstadt, J., Lindgren, R., Mack, D., McKee, P., McNulty, D., Meekins, D., Mkrtchyan, H., Nasseripour, R., Niculescu, I., Normand, K., Norum, B., Pocanic, D., Prok, Y., Raue, B., Reinhold, J., Roche, J., Kiselev, D., Savvinov, N., Sawatzky, B., Seely, M., Sick, I., Smith, C., Smith, G., Stepanyan, S., Tang, L., Tajima, S., Testa, G., Vulcan, W., Wang, K., Warren, G., Wesselmann, F. R., Wood, S., Yan, C., Yuan, L., Yun, J., Zeier, M., and Zhu, H.

Subjects
Nuclear Experiment
Abstract

We have extracted QCD matrix elements from our data on double polarized inelastic scattering of electrons on nuclei. We find the higher twist matrix element \tilde{d_2}, which arises strictly from quark- gluon interactions, to be unambiguously non zero. The data also reveal an isospin dependence of higher twist effects if we assume that the Burkhardt-Cottingham Sum rule is valid. The fundamental Bjorken sum rule obtained from the a0 matrix element is satisfied at our low momentum transfer., Comment: formerly "Nachtmann Moments of the Proton and Deuteron Spin Structure Functions"

Published
2008
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32. Quasifree Lambda, Sigma^0, and Sigma^- electroproduction from 1,2H, 3,4He, and carbon

Author

Dohrmann, F., Ahmidouch, A., Armstrong, C. S., Arrington, J., Asaturyan, R., Avery, S., Bailey, K., Bitao, H., Breuer, H., Brown, D. S., Carlini, R., Cha, J., Chant, N., Christy, E., Cochran, A., Cole, L., Crowder, J., Danagoulian, S., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Gan, L., Garrow, K., Geesaman, D. F., Gueye, P., Hafidi, K., Hinton, W., Juengst, H., Keppel, C., Liang, Y., Liu, J. H., Lung, A., Mack, D., Markowitz, P., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mtingwa, S. K., Mueller, B., Niculescu, G., Niculescu, I., Potterveld, D., Raue, B. A., Reimer, P. E., Reinhold, J., Roche, J., Sarsour, M., Sato, Y., Segel, R. E., Semenov, A., Stepanyan, S., Tadevosyan, V., Tajima, S., Tang, L., Uzzle, A., Wood, S., Yamaguchi, H., Yan, C., Yuan, L., Zeidman, B., Zeier, M., and Zihlmann, B.

Subjects
Nuclear Experiment
Abstract

Kaon electroproduction from light nuclei and hydrogen, using 1H, 2H, 3He, 4He, and Carbon targets has been measured at Jefferson Laboratory. The quasifree angular distributions of Lambda and Sigma hyperons were determined at Q^2= 0.35(GeV/c)^2 and W= 1.91GeV. Electroproduction on hydrogen was measured at the same kinematics for reference., Comment: 34 pages, 9 figures v2:minor grammatical changes, correcting typos

Published
2007
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33. Proton Spin Structure in the Resonance Region

Author

RSS Collaboration, Wesselmann, F. R., Slifer, K., Tajima, S., Aghalaryan, A., Ahmidouch, A., Asaturyan, R., Bloch, F., Boeglin, W., Bosted, P., Carasco, C., Carlini, R., Cha, J., Chen, J. P., Christy, M. E., Cole, L., Coman, L., Crabb, D., Danagoulian, S., Day, D., Dunne, J., Elaasar, M., Ent, R., Fenker, H., Frlez, E., Gan, L., Gaskell, D., Gomez, J., Hu, B., Jones, M. K., Jourdan, J., Keith, C., Keppel, C. E., Khandaker, M., Klein, A., Kramer, L., Liang, Y., Lichtenstadt, J., Lindgren, R., Mack, D., McKee, P., McNulty, D., Meekins, D., Mkrtchyan, H., Nasseripour, R., Niculescu, I., Normand, K., Norum, B., Pocanic, D., Prok, Y., Raue, B., Reinhold, J., Roche, J., Rohe, D., Rondon, O. A., Savvinov, N., Sawatzky, B., Seely, M., Sick, I., Smith, C., Smith, G., Stepanyan, S., Tang, L., Testa, G., Vulcan, W., Wang, K., Warren, G., Wood, S., Yan, C., Yuan, L., Yun, J., Zeier, M., and Zhu, H.

Subjects
Nuclear Experiment, High Energy Physics - Phenomenology
Abstract

We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum transfer of Q^2 = 1.3 GeV^2. Using the Jefferson Lab polarized electron beam, a spectrometer, and a polarized solid target, we measured the asymmetries A_parallel and A_perp to high precision, and extracted the asymmetries A_1 and A_2, and the spin structure functions g_1 and g_2. We found a notably non-zero A_perp, significant contributions from higher-twist effects, and only weak support for polarized quark--hadron duality., Comment: 6 pages, 4 figures, REVTeX4, similar to PRL submission, plots colorized and appenix added, v3: minor edit, matches PRL

Published
2006
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36. Measurement of R = sigma_L / sigma_T and the Separated Longitudinal and Transverse Structure Functions in the Nucleon Resonance Region

Author

Collaboration, The Jefferson Lab Hall C E94-110, Liang, Y., Tvaskis, V., Christy, M. E., Ahmidouch, A., Armstrong, C. S., Arrington, J., Asaturyan, R., Avery, S., Baker, O. K., Beck, D. H., Blok, H. P., Bochna, C. W., Boeglin, W., Bosted, P., Bouwhuis, M., Breuer, H., Brown, D. S., Bruell, A., Carlini, R. D., Cha, J., Chant, N. S., Cochran, A., Cole, L., Danagoulian, S., Day, D. B., Dunne, J., Dutta, D., Ent, R., Fenker, H. C., Fox, B., Gan, L., Gao, H., Garrow, K., Gaskell, D., Gasparian, A., Geesaman, D. F., Gilman, R., Gu`eye, P. L. J., Harvey, M., Holt, R. J., Jiang, X., Jones, M., Keppel, C. E., Kinney, E., Lorenzon, W., Lung, A., Mack, D. J., Markowitz, P., Martin, J. W., McIlhany, K., McKee, D., Meekins, D., Miller, M. A., Milner, R. G., Mitchell, J. H., Mkrtchyan, H., Mueller, B. A., Nathan, A., Niculescu, G., Niculescu, I., O'Neill, T. G., Papavassiliou, V., Pate, S. F., Piercey, R. B., Potterveld, D., Ransome, R. D., Reinhold, J., Rollinde, E., Rondon, O., Roos, P., Sarty, A. J., Sawafta, R., Schulte, E. C., Segbefia, E., Smith, C., Stepanyan, S., Strauch, S., Tadevosyan, V., Tang, L., Tieulent, R., Uzzle, A., Vulcan, W. F., Wood, S. A., Xiong, F., Yuan, L., Zeier, M., Zihlmann, B., and Ziskin, V.

Subjects
Nuclear Experiment
Abstract

We report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range 0.2 < Q^2 < 5.5 GeV^2. The data have been used to accurately perform 167 Rosenbluth-type longitudinal / transverse separations. The precision R = sigma_L / sigma_T data are presented here, along with the first separate values of the inelastic structure functions F_1 and F_L in this regime. The resonance longitudinal component is found to be significant, both in magnitude and in the existence of defined mass peaks. Additionally, quark-hadron duality is here observed above Q^2 = 1 GeV^2 in the separated structure functions independently., Comment: 5 pages, 4 figures

Published
2004

37. Hypernuclear Spectroscopy using the (e,e'K+) Reaction

Author

Yuan, L., Sarsour, M., Miyoshi, T., Zhu, Z., Ahmindouch, A., Androic, D., Angelescu, T., Asaturyan, R., Avery, S., Baker, O. K., Betovic, I., Breuer, H., Carlini, R., Cha, J., Christy, R. Chrien M., Cole, L., Danagoulian, S., Dehnhard, D., Elaasar, M., Empl, A., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gan, L., Garrow, K., Gasparian, A., Gueye, P., harvey, M., Hashimoto, O., Hinton, W., Hu, B., Hungerford, E., Jackson, C., Johnston, K., Juengst, H., Keppel, C., Lan, K., Liang, Y., Likhachev, V. P., Liu, J. H., Mack, D., Margaryan, A., markowitz, P., Mkrtchyan, H., Nakamura, S. N., Petkovic, T., Reinhold, J., Roche, J., Sato, Y., Sawafta, R., Simicevic, N., Smith, G., Stepanyan, S., Tadevosyan, V., Takahashi, T., Tanida, K., Tang, L., Ukai, M., Uzzle, A., Vulcan, W., Wells, S., Wood, S., Xu, G., Yamaguchi, H., and Yan, C.

Subjects
Nuclear Experiment
Abstract

A pioneering experiment in Lambda hypernuclear spectroscopy, undertaken at the Thomas Jefferson National Accelerator Facility (Jlab), was recently reported. The experiment used the high- precision, continuous electron beam at Jlab, and a special arrangement of spectrometer magnets to measure the spectrum from {nat}C and 7Li targets using the (e,e' K+)reaction. The 12B hypernuclear spectrum was previously published. This experiment is now reported in more detail, with improved results for the 12B hypernuclear spectrum. In addition, unpublished results of the 7He hypernuclear spectrum are also shown. This later spectrum indicates the need for a more detailed few-body calculation of the hypernucleus and the reaction process. The success of this experiment demonstrates that the (e,e'K+) reaction can be effectively used as a high resolution tool to study hypernuclear spectra, ant its use should be vigorously pursued., Comment: 24 pages, 10 figures

Published
2004
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45. Aggregation of Charge Acceptors on Nanocrystal Surfaces Alters Rates of Photoinduced Electron Transfer

Author

Danielle M. Cadena, Jakub K. Sowa, Daniel E. Cotton, Christopher D. Wight, Cole L. Hoffman, Holden R. Wagner, Jessica T. Boette, Emily K. Raulerson, Brent L. Iverson, Peter J. Rossky, and Sean T. Roberts

Subjects
Colloid and Surface Chemistry, Nanoparticles, Electrons, General Chemistry, Ligands, Imides, Biochemistry, Catalysis
Abstract

Semiconductor nanocrystals (NCs) interfaced with molecular ligands that function as charge and energy acceptors are an emerging platform for the design of light-harvesting, photon-upconverting, and photocatalytic materials. However, NC systems explored for these applications often feature high concentrations of bound acceptor ligands, which can lead to ligand-ligand interactions that may alter each system's ability to undergo charge and energy transfer. Here, we demonstrate that aggregation of acceptor ligands impacts the rate of photoinduced NC-to-ligand charge transfer between lead(II) sulfide (PbS) NCs and perylenediimide (PDI) electron acceptors. As the concentration of PDI acceptors is increased, we find the average electron transfer rate from PbS to PDI ligands decreases by nearly an order of magnitude. The electron transfer rate slowdown with increasing PDI concentration correlates strongly with the appearance of PDI aggregates in steady-state absorption spectra. Electronic structure calculations and molecular dynamics (MD) simulations suggest PDI aggregation slows the rate of electron transfer by reducing orbital overlap between PbS charge donors and PDI charge acceptors. While we find aggregation slows electron transfer in this system, the computational models we employ predict ligand aggregation could also be used to speed electron transfer by producing delocalized states that exhibit improved NC-molecule electronic coupling and energy alignment with NC conduction band states. Our results demonstrate that ligand aggregation can alter rates of photoinduced electron transfer between NCs and organic acceptor ligands and should be considered when designing hybrid NC:molecule systems for charge separation.

Published
2022
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