32 results on '"Sean Harrington"'
Search Results
2. Egg-laying and locomotory screens with C. elegans yield a nematode-selective small molecule stimulator of neurotransmitter release
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Sean Harrington, Jessica J. Knox, Andrew R. Burns, Ken-Loon Choo, Aaron Au, Megan Kitner, Cecile Haeberli, Jacob Pyche, Cassandra D’Amata, Yong-Hyun Kim, Jonathan R. Volpatti, Maximillano Guiliani, Jamie Snider, Victoria Wong, Bruna M. Palmeira, Elizabeth M. Redman, Aditya S. Vaidya, John S. Gilleard, Igor Stagljar, Sean R. Cutler, Daniel Kulke, James J. Dowling, Christopher M. Yip, Jennifer Keiser, Inga Zasada, Mark Lautens, and Peter J. Roy
- Subjects
Biology (General) ,QH301-705.5 - Abstract
A C. elegans-based screening approach identifies nementin as a nematode-selective nematicide that can be used synergistically with acetylcholinesterase inhibitors
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- 2022
- Full Text
- View/download PDF
3. P491: Diagnostic yield of a custom targeted genotyping panel for carrier screening of >2,000 samples: The case against cystic fibrosis-only testing
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Nisha Kanwar, Jennifer Winters, Amber McDonald, Sean Harrington, Rhonda Kuennen, Sarah Thieke, and Linda Hasadsri
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Genetics ,QH426-470 ,Medicine - Published
- 2023
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- View/download PDF
4. PhyteByte: identification of foods containing compounds with specific pharmacological properties
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Kenneth E. Westerman, Sean Harrington, Jose M. Ordovas, and Laurence D. Parnell
- Subjects
Bioactivity ,Food ,Molecule ,Natural compound ,Nutrition ,Protein target ,Computer applications to medicine. Medical informatics ,R858-859.7 ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background Phytochemicals and other molecules in foods elicit positive health benefits, often by poorly established or unknown mechanisms. While there is a wealth of data on the biological and biophysical properties of drugs and therapeutic compounds, there is a notable lack of similar data for compounds commonly present in food. Computational methods for high-throughput identification of food compounds with specific biological effects, especially when accompanied by relevant food composition data, could enable more effective and more personalized dietary planning. We have created a machine learning-based tool (PhyteByte) to leverage existing pharmacological data to predict bioactivity across a comprehensive molecular database of foods and food compounds. Results PhyteByte uses a cheminformatic approach to structure-based activity prediction and applies it to uncover the putative bioactivity of food compounds. The tool takes an input protein target and develops a random forest classifier to predict the effect of an input molecule based on its molecular fingerprint, using structure and activity data available from the ChEMBL database. It then predicts the relevant bioactivity of a library of food compounds with known molecular structures from the FooDB database. The output is a list of food compounds with high confidence of eliciting relevant biological effects, along with their source foods and associated quantities in those foods, where available. Applying PhyteByte to the human PPARG gene, we identified irigenin, sesamin, fargesin, and delta-sanshool as putative agonists of PPARG, along with previously identified agonists of this important metabolic regulator. Conclusions PhyteByte identifies food-based compounds that are predicted to interact with specific protein targets. The identified relationships can be used to prioritize food compounds for experimental or epidemiological follow-up and can contribute to the rapid development of precision approaches to new nutraceuticals as well as personalized dietary planning.
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- 2020
- Full Text
- View/download PDF
5. Staurosporine Increases Lentiviral Vector Transduction Efficiency of Human Hematopoietic Stem and Progenitor Cells
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Gretchen Lewis, Lauryn Christiansen, Jessica McKenzie, Min Luo, Eli Pasackow, Yegor Smurnyy, Sean Harrington, Philip Gregory, Gabor Veres, Olivier Negre, and Melissa Bonner
- Subjects
Genetics ,QH426-470 ,Cytology ,QH573-671 - Abstract
Lentiviral vector (LVV)-mediated transduction of human CD34+ hematopoietic stem and progenitor cells (HSPCs) holds tremendous promise for the treatment of monogenic hematological diseases. This approach requires the generation of a sufficient proportion of gene-modified cells. We identified staurosporine, a serine/threonine kinase inhibitor, as a small molecule that could be added to the transduction process to increase the proportion of genetically modified HSPCs by overcoming a LVV entry barrier. Staurosporine increased vector copy number (VCN) approximately 2-fold when added to mobilized peripheral blood (mPB) CD34+ cells prior to transduction. Limited staurosporine treatment did not affect viability of cells post-transduction, and there was no difference in in vitro colony formation compared to vehicle-treated cells. Xenotransplantation studies identified a statistically significant increase in VCN in engrafted human cells in mouse bone marrow at 4 months post-transplantation compared to vehicle-treated cells. Prostaglandin E2 (PGE2) is known to increase transduction efficiency of HSPCs through a different mechanism. Combining staurosporine and PGE2 resulted in further enhancement of transduction efficiency, particularly in short-term HSPCs. The combinatorial use of small molecules, such as staurosporine and PGE2, to enhance LVV transduction of human CD34+ cells is a promising method to improve transduction efficiency and subsequent potential therapeutic benefit of gene therapy drug products. Keywords: lentiviral, HSPC, transduction
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- 2018
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6. Broad activation of latent HIV-1 in vivo
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Kirston Barton, Bonnie Hiener, Anni Winckelmann, Thomas Aagaard Rasmussen, Wei Shao, Karen Byth, Robert Lanfear, Ajantha Solomon, James McMahon, Sean Harrington, Maria Buzon, Mathias Lichterfeld, Paul W. Denton, Rikke Olesen, Lars Østergaard, Martin Tolstrup, Sharon R. Lewin, Ole Schmeltz Søgaard, and Sarah Palmer
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Science - Abstract
Treatment of HIV-1 infected patients with latency-reversing agents (LRA) induces transcription of proviruses in CD4 T cells. Using single-genome sequencing, the authors show that the LRA-induced CD4 T cell-associated HIV RNA is genetically diverse and contains a high proportion of defective RNA.
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- 2016
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7. Complex cycles of divergence and migration shape lineage structure in the common kingsnake species complex
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Sean Harrington and Frank T. Burbrink
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Ecology ,Ecology, Evolution, Behavior and Systematics - Published
- 2022
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8. Quantum information phases in space-time: measurement-induced entanglement and teleportation on a noisy quantum processor
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Jesse Hoke, Matteo Ippoliti, Dmitry Abanin, Rajeev Acharya, Markus Ansmann, Frank Arute, Kunal Arya, Abraham Asfaw, Juan Atalaya, Ryan Babbush, Joseph Bardin, Andreas Bengtsson, Gina Bortoli, Alexandre Bourassa, Jenna Bovaird, Leon Brill, Michael Broughton, Bob Buckley, David Buell, Tim Burger, Brian Burkett, Nicholas Bushnell, Zijun Chen, Ben Chiaro, Desmond Chik, Charina Chou, Josh Cogan, Roberto Collins, Paul Conner, William Courtney, Alexander Crook, Ben Curtin, Alejandro Grajales Dau, Dripto Debroy, Alexander Del Toro Barba, Sean Demura, Augustin Di Paolo, Ilya Drozdov, Andrew Dunsworth, Daniel Eppens, Catherine Erickson, Lara Faoro, Edward Farhi, Reza Fatemi, Vinicius Ferreira, Leslie Flores Burgos, Ebrahim Forati, Austin Fowler, Brooks Foxen, William Giang, Craig Gidney, Dar Gilboa, Marissa Giustina, Raja Gosula, Jonathan Gross, Steve Habegger, Michael Hamilton, Monica Hansen, Matthew Harrigan, Sean Harrington, Paula Heu, Markus Hoffmann, Sabrina Hong, Trent Huang, Ashley Huff, William Huggins, Sergei Isakov, Justin Iveland, E. Jeffrey, Cody Jones, Pavol Juhas, Dvir Kafri, Kostyantyn Kechedzhi, Tanuj Khattar, Mostafa Khezri, Marika Kieferova, Seon Kim, Alexei Kitaev, Paul Klimov, Andrey Klots, Alexander Korotkov, Fedor Kostritsa, John Mark Kreikebaum, David Landhuis, Pavel Laptev, Kim-Ming Lau, Lily Laws, Joonho Lee, Kenny Lee, Yuri Lensky, Brian Lester, Alexander Lill, Wayne Liu, Aditya Locharla, Fionn Malone, Orion Martin, Jarrod McClean, Matt McEwen, Kevin Miao, Amanda Mieszala, Shirin Montazeri, Alexis Morvan, Ramis Movassagh, Wojciech Mruczkiewicz, Matthew Neeley, Charles Neill, Ani Nersisyan, Michael Newman, Jiun How Ng, Anthony Nguyen, Murray Nguyen, Murphy Niu, Thomas O'Brien, Seun Omonije, Alex Opremcak, Andre Petukhov, Rebecca Potter, Leonid Pryadko, Chris Quintana, Charles Rocque, Nicholas Rubin, Negar Saei, Daniel Sank, Kannan Sankaragomathi, Kevin Satzinger, Henry Schurkus, Christopher Schuster, Michael Shearn, Aaron Shorter, Noah Shutty, Shvarts Vladimir, Jindra Skruzny, W. Smith, Rolando Somma, George Sterling, Doug Strain, Marco Szalay, Alfredo Torres, Guifre Vidal, Benjamin Villalonga, Catherine Vollgraff Heidweiller, Theodore White, Bryan Woo, Cheng Xing, Z. Jamie Yao, Ping Yeh, Juhwan Yoo, Grayson Young, Adam Zalcman, Yaxing Zhang, Ningfeng Zhu, Nicholas Zobrist, Hartmut Neven, Dave Bacon, Sergio Boixo, Jeremy Hilton, Erik Lucero, Anthony Megrant, Julian Kelly, Yu Chen, Vadim Smelyanskiy, Xiao Mi, Vedika Khemani, and Pedram Roushan
- Abstract
Measurement has a special role in quantum theory1: by collapsing the wavefunction it can enable phenomena such as teleportation2 and thereby alter the "arrow of time" that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time3-10 that go beyond established paradigms for characterizing phases, either in or out of equilibrium11-13. On present-day NISQ processors14, the experimental realization of this physics is challenging due to noise, hardware limitations, and the stochastic nature of quantum measurement. Here we address each of these experimental challenges and investigate measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases—from entanglement scaling3,4 to measurement-induced teleportation18—in a unified way. We obtain finite-size signatures of a phase transition with a decoding protocol that correlates the experimental measurement record with classical simulation data. The phases display sharply different sensitivity to noise, which we exploit to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors.
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- 2023
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9. The Ultimate Study Partner: Using A Custom Chatbot To Optimize Student Studying During Law School
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Sean Harrington
- Subjects
History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2023
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10. Nemacol is a Small Molecule Inhibitor of C. elegans Vesicular Acetylcholine Transporter with Anthelmintic Potential
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Sean Harrington, Jacob Pyche, Andrew R. Burns, Tina Spalholz, Rachel J. Baker, Justin Ching, Mark Lautens, Daniel Kulke, Winnie Deuther-Conrad, Peter Brust, and Peter J. Roy
- Abstract
Nematode parasites of humans and livestock pose a significant burden to human health, economic development, and food security. Anthelmintic drug resistance is widespread among parasites of livestock and many nematode parasites of humans lack effective treatments. Here, we present a nitrophenyl-piperazine scaffold that induces motor defects rapidly in the model nematode Caenorhabditis elegans. We call this scaffold Nemacol and show that it inhibits the vesicular acetylcholine transporter (VAChT), a target recognized by commercial animal and crop health groups as a viable anthelmintic target. We demonstrate that it is possible to create Nemacol analogs that maintain potent in vivo activity whilst lowering their affinity to the mammalian VAChT 10-fold. We also show that Nemacol synergizes with the anthelmintic ivermectin to kill C. elegans. Hence, Nemacol represents a promising new anthelmintic scaffold that acts through an identified viable anthelmintic target.One sentence summaryA small molecule screen identifies a vesicular acetylcholine transporter inhibitor scaffold that incapacitates parasitic nematodes
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- 2022
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11. Potential Role of Inflammation-Promoting Biliary Microbiome in Primary Sclerosing Cholangitis and Cholangiocarcinoma
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Katsuyuki Miyabe, Vinay Chandrasekhara, Nicha Wongjarupong, Jun Chen, Lu Yang, Stephen Johnson, Nicholas Chia, Marina Walther-Antonio, Janet Yao, Sean Harrington, Cynthia Nordyke, John Eaton, Andrea Gossard, Sharad Oli, Hamdi Ali, Sravanthi Lavu, Nasra Giama, Fatima Hassan, Hawa Ali, Felicity Enders, Sumera Ilyas, Gregory Gores, Mark Topazian, Purna Kashyap, and Lewis Roberts
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Cancer Research ,Oncology ,parasitic diseases ,digestive, oral, and skin physiology ,cardiovascular system ,bile microbiome ,cholangiocarcinoma ,primary sclerosing cholangitis ,digestive system ,digestive system diseases - Abstract
Background: Primary sclerosing cholangitis (PSC) is a major risk factor for cholangiocarcinoma (CCA). We investigated biliary and fecal microbiota to determine whether specific microbes in the bile or stool are associated with PSC or CCA. Methods: Bile was obtained from 32 patients with PSC, 23 with CCA with PSC, 26 with CCA without PSC, and 17 controls. Over 90% of bile samples were from patients with perihilar CCA. Stool was obtained from 31 patients with PSC (11 were matched to bile), 16 with CCA with PSC (10 matched to bile), and 11 with CCA without PSC (6 matched to bile). Microbiota composition was assessed using 16SrRNA-marker-based sequencing and was compared between groups. Results: Bile has a unique microbiota distinguished from negative DNA controls and stool. Increased species richness and abundance of Fusobacteria correlated with duration of PSC and characterized the biliary microbiota in CCA. Stool microbiota composition showed no significant differences between groups. Conclusions: We identified a unique microbial signature in the bile of patients with increased duration of PSC or with CCA, suggesting a role for microbiota-driven inflammation in the pathogenesis and or progression to perihilar CCA. Further studies are needed to test this hypothesis.
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- 2022
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12. A novel allosteric modulator of the cannabinoid CB1 receptor ameliorates hyperdopaminergia endophenotypes in rodent models
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Amy J. Ramsey, Nirunthan Sivananthan, Matthieu Schapira, W. McIntyre Burnham, Vincent M. Lam, Mostafa H. Abdelrahman, Sean Harrington, David B. Finlay, Ruth A. Ross, Jibran Y. Khokhar, Chun Kit Li, Laurent Trembleau, Iain R. Greig, Ali Salahpour, Kim S. Sugamori, Catharine A. Mielnik, Michelle Glass, and Hayley H. A. Thorpe
- Subjects
Agonist ,Allosteric modulator ,Cannabinoid receptor ,medicine.drug_class ,Endophenotypes ,medicine.medical_treatment ,Rodentia ,Article ,Mice ,Sensorimotor processing ,Receptor, Cannabinoid, CB1 ,Dopamine ,medicine ,Animals ,Receptors, Cannabinoid ,Dopamine transporter ,Pharmacology ,Mice, Knockout ,biology ,Chemistry ,Cannabinoids ,Dopaminergic ,Endocannabinoid system ,Psychiatry and Mental health ,biology.protein ,Cannabinoid ,Neuroscience ,medicine.drug - Abstract
The endocannabinoid system (eCBs) encompasses the endocannabinoids, their synthetic and degradative enzymes, and cannabinoid (CB) receptors. The eCBs mediates inhibition of neurotransmitter release and acts as a major homeostatic system. Many aspects of the eCBs are altered in a number of psychiatric disorders including schizophrenia, which is characterized by dysregulation of dopaminergic signaling. The GluN1-Knockdown (GluN1KD) and Dopamine Transporter Knockout (DATKO) mice are models of hyperdopaminergia, which display abnormal psychosis-related behaviors, including hyperlocomotion and changes in pre-pulse inhibition (PPI). Here, we investigate the ability of a novel CB1 receptor (CB1R) allosteric modulator, ABM300, to ameliorate these dysregulated behaviors. ABM300 was characterized in vitro (receptor binding, β-arrestin2 recruitment, ERK1/2 phosphorylation, cAMP inhibition) and in vivo (anxiety-like behaviors, cannabimimetic effects, novel environment exploratory behavior, pre-pulse inhibition, conditioned avoidance response) to assess the effects of the compound in dysregulated behaviors within the transgenic models. In vitro, ABM300 increased CB1R agonist binding but acted as an inhibitor of CB1R agonist induced signaling, including β-arrestin2 translocation, ERK phosphorylation and cAMP inhibition. In vivo, ABM300 did not elicit anxiogenic-like or cannabimimetic effects, but it decreased novelty-induced hyperactivity, exaggerated stereotypy, and vertical exploration in both transgenic models of hyperdopaminergia, as well as normalizing PPI in DATKO mice. The data demonstrate for the first time that a CB1R allosteric modulator ameliorates the behavioral deficits in two models of increased dopamine, warranting further investigation as a potential therapeutic target in psychiatry.
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- 2020
13. Dartmouth Outward Bound Center and the rise of experiential education, 1957–1976
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Sean Harrington, Jayson O. Seaman, and Robert MacArthur
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History ,Outdoor education ,Humanistic psychology ,National service ,Mainstream ,Experiential education ,Gender studies ,Context (language use) ,Sociology ,Human Potential Movement ,Intellectual history ,Education - Abstract
PurposeThe article discusses Outward Bound's participation in the human potential movement through its incorporation of T-group practices and the reform language of experiential education in the late 1960s and early 1970s.Design/methodology/approachThe article reports on original research conducted using materials from Dartmouth College and other Outward Bound collections from 1957 to 1976. It follows a case study approach to illustrate themes pertaining to Outward Bound's creation and evolution in the United States, and the establishment of experiential education more broadly.FindingsBuilding on prior research (Freeman, 2011; Millikan, 2006), the present article elaborates on the conditions under which Outward Bound abandoned muscular Christianity in favor of humanistic psychology. Experiential education provided both a set of practices and a reform language that helped Outward Bound expand into the educational mainstream, which also helped to extend self-expressive pedagogies into formal and nonformal settings.Research limitations/implicationsThe Dartmouth Outward Bound Center's tenure coincided with and reflected broader cultural changes, from the cold war motif of spiritual warfare, frontier masculinity and national service to the rise of self-expression in education. Future scholars can situate specific curricular initiatives in the context of these paradigms, particularly in outdoor education.Originality/valueThe article draws attention to one of the forms that the human potential movement took in education – experiential education – and the reasons for its adoption. It also reinforces emerging understandings of post-WWII American outdoor education as a product of the cold war and reflective of subsequent changes in the wider culture to a narrower focus on the self.
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- 2020
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14. Nementin is a Nematode-Selective Small Molecule Agonist of Neurotransmitter Release
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Sean Harrington, Jessica J. Knox, Andrew R. Burns, Ken-Loon Choo, Aaron Au, Megan Kitner, Cecile Haeberli, Jacob Pyche, Cassandra D’Amata, Yong-Hyun Kim, Jonathan R. Volpatti, Maximillano Guiliani, Jamie Snider, Victoria Wong, Bruna M. Palmeira, Elizabeth M. Redman, Aditya S. Vaidya, John S. Gilleard, Igor Stagljar, Sean R. Cutler, Daniel Kulke, James J. Dowling, Christopher M. Yip, Jennifer Keiser, Inga Zasada, Mark Lautens, and Peter J. Roy
- Abstract
Nematode parasites of humans, livestock and crops pose a significant burden on human health and welfare. Alarmingly, parasitic nematodes of animals have rapidly evolved resistance to anthelmintic drugs, and traditional nematicides that protect crops are facing increasing restrictions because of poor phylogenetic selectivity. Here, we present a pipeline that exploits multiple motor outputs of the model nematode C. elegans for nematicide discovery. This pipeline yielded multiple compounds that selectively kill and/or immobilize diverse nematode parasites. We focus on one compound that induces violent convulsions and paralysis that we call Nementin. We find that Nementin agonizes neuronal dense core vesicle release, which in turn agonizes cholinergic signaling. Consequently, Nementin synergistically enhances the potency of widely-used non-selective acetylcholinesterase inhibitors (AChEIs), but in a nematode-selective manner. Nementin therefore has the potential to reduce the environmental impact of toxic AChEI pesticides used to control nematode infections and infestations.Significance StatementParasitic nematodes pose a considerable burden to human health and food security. Small molecules that have traditionally been used to control these parasites have either been banned because of toxicity concerns or are being rendered ineffective because of the evolution of resistance. Significant gaps in our nematicidal toolkit are therefore becoming an alarming problem. Here, we describe our discovery of Nementin, a small molecule that disrupts the nematode nervous system but is ineffective against non-targeted organisms. We find that Nementin also enhances the activity of non-selective pesticides but does so in a nematode-selective manner. Hence, Nementin is an innovative solution to combat parasitic nematodes in a safe and phylum-selective manner.One-Sentence SummaryA C. elegans-based screening pipeline identifies a selective nematicide that also potentiates acetylcholinesterase inhibitors.
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- 2022
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15. Purification-based quantum error mitigation of pair-correlated electron simulations
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Thomas O'Brien, Gian-Luca Anselmetti, Fotios Gkritsis, Vincent Elfving, Stefano Polla, William Huggins, Oumarou Oumarou, Kostyantyn Kechedzhi, Dmitry Abanin, Rajeev Acharya, Igor Aleiner, Richard Allen, Trond Andersen, Kyle Anderson, Markus Ansmann, Frank Arute, Kunal Arya, Abraham Asfaw, Juan Atalaya, Dave Bacon, Joseph Bardin, Andreas Bengtsson, Sergio Boixo, Gina Bortoli, Alexandre Bourassa, Jenna Bovaird, Leon Brill, Michael Broughton, Bob Buckley, David Buell, Tim Burger, Brian Burkett, Nicholas Bushnell, Juan Campero, Yu Chen, Zijun Chen, Ben Chiaro, Desmond Chik, Josh Cogan, Roberto Collins, Paul Conner, William Courtney, Alexander Crook, Ben Curtin, Dripto Debroy, Alexander Del Toro Barba, Sean Demura, Ilya Drozdov, Andrew Dunsworth, Daniel Eppens, Catherine Erickson, Lara Faoro, Edward Farhi, Reza Fatemi, Vinicius Ferreira, Leslie Flores Burgos, Ebrahim Forati, Austin Fowler, Brooks Foxen, William Giang, Craig Gidney, Dar Gilboa, Marissa Giustina, Raja Gosula, Alejandro Grajales Dau, Jonathan Gross, Steve Habegger, Michael Hamilton, Monica Hansen, Matthew Harrigan, Sean Harrington, Paula Heu, Jeremy Hilton, Markus Hoffmann, Sabrina Hong, Trent Huang, Ashley Huff, L. B. Ioffe, Sergei Isakov, Justin Iveland, E. Jeffrey, Zhang Jiang, Cody Jones, Pavol Juhas, Dvir Kafri, Julian Kelly, Tanuj Khattar, Mostafa Khezri, Marika Kieferova, Seon Kim, Paul Klimov, Andrey Klots, Alexander Korotkov, Fedor Kostritsa, John Mark Kreikebaum, David Landhuis, Pavel Laptev, Kim-Ming Lau, Lily Laws, Joonho Lee, Kenny Lee, Brian Lester, Alexander Lill, Wayne Liu, William Livingston, Aditya Locharla, Erik Lucero, Fionn Malone, Salvatore Mandra, Orion Martin, Steven Martin, Jarrod McClean, Trevor McCourt, Matthew McEwen, Anthony Megrant, Xiao Mi, Kevin Miao, Amanda Mieszala, Masoud Mohseni, Shirin Montazeri, Alexis Morvan, Ramis Movassagh, Wojciech Mruczkiewicz, Ofer Naaman, Matthew Neeley, Charles Neill, Ani Nersisyan, Hartmut Neven, Michael Newman, Jiun How Ng, Anthony Nguyen, Murray Nguyen, Murphy Niu, Seun Omonije, Alex Opremcak, Andre Petukhov, Rebecca Potter, Leonid Pryadko, Chris Quintana, Charles Rocque, Pedram Roushan, Negar Saei, Daniel Sank, Kannan Sankaragomathi, Kevin Satzinger, Henry Schurkus, Michael Shearn, Aaron Shorter, Noah Shutty, Shvarts Vladimir, Jindra Skruzny, Vadim Smelyanskiy, W. Clarke Smith, Rolando Somma, George Sterling, Doug Strain, Marco Szalay, Douglas Thor, Alfredo Torres, Guifre Vidal, Benjamin Villalonga, Catherine Vollgraff Heidweiller, Theodore White, Bryan Woo, Cheng Xing, Z. Jamie Yao, Ping Yeh, Juhwan Yoo, Grayson Young, Adam Zalcman, Yaxing Zhang, Ningfeng Zhu, Nicholas Zobrist, Christian Gogolin, Ryan Babbush, and Nicholas Rubin
- Subjects
Quantum Physics ,FOS: Physical sciences ,Quantum Physics (quant-ph) - Abstract
An important measure of the development of quantum computing platforms has been the simulation of increasingly complex physical systems. Prior to fault-tolerant quantum computing, robust error mitigation strategies are necessary to continue this growth. Here, we study physical simulation within the seniority-zero electron pairing subspace, which affords both a computational stepping stone to a fully correlated model, and an opportunity to validate recently introduced ``purification-based'' error-mitigation strategies. We compare the performance of error mitigation based on doubling quantum resources in time (echo verification) or in space (virtual distillation), on up to $20$ qubits of a superconducting qubit quantum processor. We observe a reduction of error by one to two orders of magnitude below less sophisticated techniques (e.g. post-selection); the gain from error mitigation is seen to increase with the system size. Employing these error mitigation strategies enables the implementation of the largest variational algorithm for a correlated chemistry system to-date. Extrapolating performance from these results allows us to estimate minimum requirements for a beyond-classical simulation of electronic structure. We find that, despite the impressive gains from purification-based error mitigation, significant hardware improvements will be required for classically intractable variational chemistry simulations., Comment: 10 pages, 13 page supplementary material, 12 figures. Experimental data available at https://doi.org/10.5281/zenodo.7225821
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- 2022
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16. PhyteByte: identification of foods containing compounds with specific pharmacological properties
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Sean Harrington, Laurence D. Parnell, Jose M. Ordovas, and Kenneth Westerman
- Subjects
Protein target ,Phytochemicals ,Computational biology ,Biology ,Health benefits ,Natural compound ,lcsh:Computer applications to medicine. Medical informatics ,Molecular Fingerprint ,Biochemistry ,Bioactivity ,03 medical and health sciences ,0302 clinical medicine ,Nutraceutical ,Structural Biology ,Humans ,lcsh:QH301-705.5 ,Molecular Biology ,030304 developmental biology ,Nutrition ,0303 health sciences ,Applied Mathematics ,digestive, oral, and skin physiology ,Molecule ,Food composition data ,chEMBL ,Computer Science Applications ,lcsh:Biology (General) ,Food ,030220 oncology & carcinogenesis ,FooDB ,lcsh:R858-859.7 ,Identification (biology) ,DNA microarray ,Software ,Food Analysis - Abstract
Background Phytochemicals and other molecules in foods elicit positive health benefits, often by poorly established or unknown mechanisms. While there is a wealth of data on the biological and biophysical properties of drugs and therapeutic compounds, there is a notable lack of similar data for compounds commonly present in food. Computational methods for high-throughput identification of food compounds with specific biological effects, especially when accompanied by relevant food composition data, could enable more effective and more personalized dietary planning. We have created a machine learning-based tool (PhyteByte) to leverage existing pharmacological data to predict bioactivity across a comprehensive molecular database of foods and food compounds. Results PhyteByte uses a cheminformatic approach to structure-based activity prediction and applies it to uncover the putative bioactivity of food compounds. The tool takes an input protein target and develops a random forest classifier to predict the effect of an input molecule based on its molecular fingerprint, using structure and activity data available from the ChEMBL database. It then predicts the relevant bioactivity of a library of food compounds with known molecular structures from the FooDB database. The output is a list of food compounds with high confidence of eliciting relevant biological effects, along with their source foods and associated quantities in those foods, where available. Applying PhyteByte to the human PPARG gene, we identified irigenin, sesamin, fargesin, and delta-sanshool as putative agonists of PPARG, along with previously identified agonists of this important metabolic regulator. Conclusions PhyteByte identifies food-based compounds that are predicted to interact with specific protein targets. The identified relationships can be used to prioritize food compounds for experimental or epidemiological follow-up and can contribute to the rapid development of precision approaches to new nutraceuticals as well as personalized dietary planning.
- Published
- 2020
17. Staurosporine Increases Lentiviral Vector Transduction Efficiency of Human Hematopoietic Stem and Progenitor Cells
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Olivier Negre, Jessica McKenzie, Melissa Bonner, Sean Harrington, Yegor Smurnyy, Philip A. Gregory, Lauryn Christiansen, Gabor Istvan Veres, Min Luo, Gretchen Lewis, and Eli Pasackow
- Subjects
0301 basic medicine ,lcsh:QH426-470 ,Genetic enhancement ,CD34 ,Article ,Viral vector ,03 medical and health sciences ,Transduction (genetics) ,Genetics ,medicine ,Staurosporine ,Progenitor cell ,lcsh:QH573-671 ,Molecular Biology ,lentiviral ,Chemistry ,lcsh:Cytology ,transduction ,Cell biology ,Haematopoiesis ,lcsh:Genetics ,030104 developmental biology ,medicine.anatomical_structure ,HSPC ,Molecular Medicine ,Bone marrow ,medicine.drug - Abstract
Lentiviral vector (LVV)-mediated transduction of human CD34+ hematopoietic stem and progenitor cells (HSPCs) holds tremendous promise for the treatment of monogenic hematological diseases. This approach requires the generation of a sufficient proportion of gene-modified cells. We identified staurosporine, a serine/threonine kinase inhibitor, as a small molecule that could be added to the transduction process to increase the proportion of genetically modified HSPCs by overcoming a LVV entry barrier. Staurosporine increased vector copy number (VCN) approximately 2-fold when added to mobilized peripheral blood (mPB) CD34+ cells prior to transduction. Limited staurosporine treatment did not affect viability of cells post-transduction, and there was no difference in in vitro colony formation compared to vehicle-treated cells. Xenotransplantation studies identified a statistically significant increase in VCN in engrafted human cells in mouse bone marrow at 4 months post-transplantation compared to vehicle-treated cells. Prostaglandin E2 (PGE2) is known to increase transduction efficiency of HSPCs through a different mechanism. Combining staurosporine and PGE2 resulted in further enhancement of transduction efficiency, particularly in short-term HSPCs. The combinatorial use of small molecules, such as staurosporine and PGE2, to enhance LVV transduction of human CD34+ cells is a promising method to improve transduction efficiency and subsequent potential therapeutic benefit of gene therapy drug products. Keywords: lentiviral, HSPC, transduction
- Published
- 2018
18. Pegylated Interferon-α–Induced Natural Killer Cell Activation Is Associated With Human Immunodeficiency Virus-1 DNA Decline in Antiretroviral Therapy–Treated HIV-1/Hepatitis C Virus–Coinfected Patients
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Sean Harrington, Mathias Lichterfeld, Manuel Leal, Samantha Tse, Ezequiel Ruiz-Mateos, Stephane Hua, Pilar Garcia-Broncano, Xu G. Yu, Miguel Genebat, Giulia Marchetti, Selena Vigano, Jordi Negron, Ouyang Zhengyu, and Salvador Resino
- Subjects
Adult ,Male ,0301 basic medicine ,Microbiology (medical) ,Hepatitis C virus ,Alpha interferon ,HIV Infections ,Hepacivirus ,Lymphocyte Activation ,medicine.disease_cause ,gag Gene Products, Human Immunodeficiency Virus ,Polyethylene Glycols ,Cohort Studies ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Antiretroviral Therapy, Highly Active ,Ribavirin ,medicine ,Humans ,030212 general & internal medicine ,Articles and Commentaries ,Aged ,Disease Reservoirs ,Coinfection ,business.industry ,Interferon-alpha ,Hepatitis C ,Middle Aged ,Viral Load ,medicine.disease ,NKG2D ,Virology ,Recombinant Proteins ,Killer Cells, Natural ,030104 developmental biology ,Infectious Diseases ,chemistry ,Spain ,DNA, Viral ,HIV-1 ,Female ,business ,Natural killer cell activation ,Viral load ,CD8 - Abstract
BACKGROUND: Interferon alpha (IFN-α) can potently reduce human immunodeficiency virus type 1 (HIV-1) replication in tissue culture and animal models, but may also modulate residual viral reservoirs that persist despite suppressive antiretroviral combination therapy. However, mechanisms leading to viral reservoir reduction during IFN-α treatment are unclear. METHODS: We analyzed HIV-1 gag DNA levels in CD4 T cells by digital droplet polymerase chain reaction and CD8 T-cell and natural killer (NK) cell phenotypes by flow cytometry in a cohort of antiretroviral therapy–treated HIV-1/hepatitis C virus–coinfected patients (n = 67) undergoing treatment for hepatitis C infection with pegylated IFN-α and ribavirin for an average of 11 months. RESULTS: We observed that IFN-α treatment induced a significant decrease in CD4 T-cell counts (P < .0001), in CD4 T-cell–associated HIV-1 DNA copies (P = .002) and in HIV-1 DNA copies per microliter of blood (P < .0001) in our study patients. Notably, HIV-1 DNA levels were unrelated to HIV-1–specific CD8 T-cell responses. In contrast, proportions of total NK cells, CD56(bright)CD16(–) NK cells, and CD56(bright)CD16(+) NK cells were significantly correlated with reduced levels of CD4 T-cell–associated HIV-1 DNA during IFN-α treatment, especially when coexpressing the activation markers NKG2D and NKp30. CONCLUSIONS: These data suggest that the reduction of viral reservoir cells during treatment with IFN-α is primarily attributable to antiviral activities of NK cells.
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- 2017
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19. Preferential susceptibility of Th9 and Th2 CD4+ T cells to X4-tropic HIV-1 infection
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Fatema Z. Chowdhury, Sean Harrington, Xiaoming Sun, Eric S. Rosenberg, Xu G. Yu, Nina Orlova-Fink, and Mathias Lichterfeld
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0301 basic medicine ,Receptors, CXCR4 ,viruses ,Immunology ,Biology ,CXCR4 ,Article ,03 medical and health sciences ,Receptors, HIV ,0302 clinical medicine ,T-Lymphocyte Subsets ,Humans ,Immunology and Allergy ,Receptor ,Tropism ,Effector ,virus diseases ,T-Lymphocytes, Helper-Inducer ,Antimicrobial ,biology.organism_classification ,Virology ,In vitro ,Viral Tropism ,030104 developmental biology ,Infectious Diseases ,Vesicular stomatitis virus ,030220 oncology & carcinogenesis ,HIV-1 ,Tissue tropism - Abstract
Objective The functional polarization of CD4 T cells determines their antimicrobial effector profile, but may also impact the susceptibility to infection with HIV-1. Here, we analyzed the susceptibility of CD4 T cells with different functional polarization to infection with X4 and R5-tropic HIV-1. Methods CD4 T cells with a Th1, Th2, Th17, and Th9 polarization were subjected to in-vitro infection assays with X4, R5, or vesicular stomatitis virus-G protein-pseudotyped HIV-1. In addition, we sorted differentially polarized CD4 T-cell subsets from individuals treated with antiretroviral therapy and analyzed the tropism of viral env sequences. Results Th9-polarized CD4 T cells and, to a lesser extent, Th2-polarized CD4 T cells expressed higher surface levels of CXCR4, and are more permissive to X4-tropic infection in vitro. In contrast, Th1 and Th17 CD4 T cells exhibited stronger surface expression of CCR5, and were more susceptible to infection with R5-tropic viruses. Correspondingly, the distribution of X4-tropic viral sequences in antiretroviral therapy-treated HIV-1-infected patients was biased toward Th9/Th2 cells, whereas R5-tropic sequences were more frequently observed in Th17 cells. Conclusion CD4 T-cell polarization is associated with a distinct susceptibility to X4 and R5-tropic HIV-1 infection.
- Published
- 2017
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20. The loss of CCR6+ and CD161+ CD4+ T-cell homeostasis contributes to disease progression in SIV-infected rhesus macaques
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Mirko Paiardini, Sean Harrington, Barbara Cervasi, Justin L. Harper, Sara Paganini, Robin I. Iriele, Mathias Lichterfeld, Emily S. Ryan, Xavier Alvarez, Luca Micci, Colleen S. McGary, Guido Silvestri, Aftab A. Ansari, and Kirk A. Easley
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0301 basic medicine ,Disease reservoir ,Immunology ,virus diseases ,chemical and pharmacologic phenomena ,hemic and immune systems ,Inflammation ,C-C chemokine receptor type 6 ,Biology ,Simian immunodeficiency virus ,medicine.disease_cause ,Virology ,3. Good health ,03 medical and health sciences ,030104 developmental biology ,Mucosal immunology ,Intestinal mucosa ,Immunity ,medicine ,Immunology and Allergy ,medicine.symptom ,Homeostasis - Abstract
Although previous studies have shown that CD4+ T cells expressing CCR6 and CD161 are depleted from blood during HIV infection, the mechanisms underlying their loss remain unclear. In this study, we investigated how the homeostasis of CCR6+ and CD161+ CD4+ T cells contributes to SIV disease progression and the mechanisms responsible for their loss from circulation. By comparing SIV infection in rhesus macaques (RMs) and natural host sooty mangabeys (SMs), we found that the loss of CCR6+ and CD161+ CD4+ T cells from circulation is a distinguishing feature of progressive SIV infection in RMs. Furthermore, while viral infection critically contributes to the loss of CD161+CCR6-CD4+ T cells, a redistribution of CCR6+CD161- and CCR6+CD161+CD4+ T cells from the blood to the rectal mucosa is a chief mechanism for their loss during SIV infection. Finally, we provide evidence that the accumulation of CCR6+CD4+ T cells in the mucosa is damaging to the host by demonstrating their reduction from this site following initiation of antiretroviral therapy in SIV-infected RMs and their lack of accumulation in SIV-infected SMs. These data emphasize the importance of maintaining CCR6+ and CD161+ CD4+ T-cell homeostasis, particularly in the mucosa, to prevent disease progression during pathogenic HIV/SIV infection.
- Published
- 2017
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21. Clonal expansion of genome-intact HIV-1 in functionally polarized Th1 CD4+ T cells
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Sean Harrington, Bruce D. Walker, Hsiao-Rong Chen, Krista L. Dong, Kavidha Reddy, Nina Orlova-Fink, Thumbi Ndung'u, Xu G. Yu, Stephane Hua, Fatema Z. Chowdhury, Kevin Einkauf, Hsiao-Hsuan Kuo, Xiaoming Sun, Guinevere Q. Lee, Mathias Lichterfeld, Eric S. Rosenberg, and Zhengyu Ouyang
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Adult ,Male ,0301 basic medicine ,030106 microbiology ,Human immunodeficiency virus (HIV) ,Genome, Viral ,Biology ,medicine.disease_cause ,Peripheral blood mononuclear cell ,Genome ,Viral gene ,DNA sequencing ,03 medical and health sciences ,chemistry.chemical_compound ,medicine ,Humans ,High-Throughput Nucleotide Sequencing ,General Medicine ,Middle Aged ,Th1 Cells ,Provirus ,Molecular biology ,Antiretroviral therapy ,Virus Latency ,030104 developmental biology ,chemistry ,HIV-1 ,Female ,DNA ,Research Article - Abstract
HIV-1 causes a chronic, incurable disease due to its persistence in CD4+ T cells that contain replication-competent provirus, but exhibit little or no active viral gene expression and effectively resist combination antiretroviral therapy (cART). These latently infected T cells represent an extremely small proportion of all circulating CD4+ T cells but possess a remarkable long-term stability and typically persist throughout life, for reasons that are not fully understood. Here we performed massive single-genome, near-full-length next-generation sequencing of HIV-1 DNA derived from unfractionated peripheral blood mononuclear cells, ex vivo-isolated CD4+ T cells, and subsets of functionally polarized memory CD4+ T cells. This approach identified multiple sets of independent, near-full-length proviral sequences from cART-treated individuals that were completely identical, consistent with clonal expansion of CD4+ T cells harboring intact HIV-1. Intact, near-full-genome HIV-1 DNA sequences that were derived from such clonally expanded CD4+ T cells constituted 62% of all analyzed genome-intact sequences in memory CD4 T cells, were preferentially observed in Th1-polarized cells, were longitudinally detected over a duration of up to 5 years, and were fully replication- and infection-competent. Together, these data suggest that clonal proliferation of Th1-polarized CD4+ T cells encoding for intact HIV-1 represents a driving force for stabilizing the pool of latently infected CD4+ T cells.
- Published
- 2017
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22. Beasts of the Forest : Denizens of the Dark Woods
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Jon Hackett, Seán Harrington, Jon Hackett, and Seán Harrington
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- Supernatural in literature, Forests in literature, Forests in art, Supernatural--Folklore, Forests and forestry--Folklore, Supernatural in motion pictures
- Abstract
An interdisciplinary engagement with the forest and its monsters through critical readings of folklore, fiction, film, music video and animation.Within the text there are a multitude of convergent critical perspectives used to engage and explore fictional and real monsters of the forest in media and folklore. The collection features chapters from a variety of academic perspectives: film and media studies, cultural studies, queer theory, Tolkien studies, mythology and popular music are featured. Under examination are a wide range of narratives and media forms that represent, reimagine and create the werewolves, witches and weird apparitions that inhabit the forest, along with the forest as a monstrous entity in itself.Whether they be our shelter and safe-haven or the domain of malevolent spirits and sprites, forests have the capacity to horrify and threaten those that venture into them without permission. Human interference has continually threatened forests across the world, yet this threat is reversed in myth, folklore and more recent cultural forms. This collection ranges widely to analyze how forests figure in contemporary culture, as well as the wider contexts in which such representations are inserted.
- Published
- 2019
23. Beasts of the Deep : Sea Creatures and Popular Culture
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Jon Hackett, Seán Harrington, Jon Hackett, and Seán Harrington
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- Animals, Mythical, Sea monsters
- Abstract
Beasts of the Deep: Sea Creatures and Popular Culture offers its readers an in-depth and interdisciplinary engagement with the sea and its monstrous inhabitants; through critical readings of folklore, weird fiction, film, music, radio and digital games. Within the text there are a multitude of convergent critical perspectives used to engage and explore fictional and real monsters of the sea in media and folklore. The collection features chapters from a variety of academic perspectives; post- modernism, psychoanalysis, industrial-organisational analysis, fandom studies, sociology and philosophy are featured. Under examination are a wide range of narratives and media forms that represent, reimagine and create the Kraken, mermaids, giant sharks, sea draugrs and even the weird creatures of H.P. Lovecraft.Beasts of the Deep offers an expansive study of our sea-born fears and anxieties, that are crystallised in a variety of monstrous forms. Repeatedly the chapters in the collection encounter the contemporary relevance of our fears of the sea and its inhabitants – through the dehumanising media depictions of refugees in the Mediterranean to the encroaching ecological disasters of global warming, pollution and the threat of mass marine extinction.
- Published
- 2018
24. Developing, delivering and evaluating primary mental health care: the co-production of a new complex intervention
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Peter Rosbottom, Joanne Reeve, Sean Harrington, Jane Watkins, and Lucy Cooper
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Adult ,Male ,Evidence-based practice ,Process management ,Interprofessional Relations ,General Practice ,Context (language use) ,Health informatics ,Health administration ,Translational Research, Biomedical ,03 medical and health sciences ,Normalisation Process Theory (NPT) ,Practice-based evidence ,0302 clinical medicine ,Patient satisfaction ,Nursing ,Complex intervention ,Process theory ,Health care ,Medicine ,Humans ,030212 general & internal medicine ,Cooperative Behavior ,Aged ,Primary Health Care ,business.industry ,030503 health policy & services ,Nursing research ,Health Policy ,Mental Disorders ,Process Assessment, Health Care ,Middle Aged ,Translational research ,Community Mental Health Services ,Mental Health ,England ,Patient Satisfaction ,Evidence-Based Practice ,Flipped care ,Female ,0305 other medical science ,business ,RA ,Delivery of Health Care ,Research Article - Abstract
Background Health services face the challenges created by complex problems, and so need complex intervention solutions. However they also experience ongoing difficulties in translating findings from research in this area in to quality improvement changes on the ground. BounceBack was a service development innovation project which sought to examine this issue through the implementation and evaluation in a primary care setting of a novel complex intervention. Methods The project was a collaboration between a local mental health charity, an academic unit, and GP practices. The aim was to translate the charity’s model of care into practice-based evidence describing delivery and impact. Normalisation Process Theory (NPT) was used to support the implementation of the new model of primary mental health care into six GP practices. An integrated process evaluation evaluated the process and impact of care. Results Implementation quickly stalled as we identified problems with the described model of care when applied in a changing and variable primary care context. The team therefore switched to using the NPT framework to support the systematic identification and modification of the components of the complex intervention: including the core components that made it distinct (the consultation approach) and the variable components (organisational issues) that made it work in practice. The extra work significantly reduced the time available for outcome evaluation. However findings demonstrated moderately successful implementation of the model and a suggestion of hypothesised changes in outcomes. Conclusions The BounceBack project demonstrates the development of a complex intervention from practice. It highlights the use of Normalisation Process Theory to support development, and not just implementation, of a complex intervention; and describes the use of the research process in the generation of practice-based evidence. Implications for future translational complex intervention research supporting practice change through scholarship are discussed. Electronic supplementary material The online version of this article (doi:10.1186/s12913-016-1726-6) contains supplementary material, which is available to authorized users.
- Published
- 2015
25. A Dual Image Sensor Approach for Automated, High Resolution, Region-of-Interest Imaging in a 96-Well Plate
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Christopher M. Yip, Maximiliano Giuliani, Aaron Au, Peter J. Roy, and Sean Harrington
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business.industry ,Computer science ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Biophysics ,High resolution ,Image processing ,Python (programming language) ,Image stitching ,Region of interest ,Segmentation ,Computer vision ,Artificial intelligence ,96 well plate ,Image sensor ,business ,computer ,computer.programming_language - Abstract
Phenotypic screens are performed on model organisms to understand how chemical compounds affect biological systems. High-throughput devices are needed to efficiently gather large volumes of data for these screens. Recently we developed a low cost high-throughput imaging solution to capture the effects of chemicals on the egg-laying behaviour of C. elegans. We present a second-generation prototype capable of high-resolution (0.2 µm/px) imaging of individual worms and their internal structures. It features an automatic real time segmentation of C. elegans worms and is compatible with 96-well plates. In order to maximize efficiency in data collection, we developed an approach for simultaneous dual imaging through a single objective. A low-resolution (15 µm/px) arm continuously collects images of an entire well using a CCD camera (1280 px by 1024 px). The images are continuously fed into a Python image algorithm that tracks the movement of the worms in regions of interest (ROIs). Using this information, high resolution images of the worms are captured using a linescan camera (8000 px). This solution provides automated high-resolution imaging minimizing acquisition time by eliminating the need for multiple objectives, allowing image collection with a continuously moving system (high speed linescan camera) and minimizing the amount of stitching (large linescan sensor). The scan time of a 96-well plate is proportional to the number of ROIs, which is significantly less than imaging an entire plate. The high-resolution images can be fed into an image processing pipeline that will be able to classify the effects of chemicals on the internal structure of the worms. Simultaneous acquisition of high and low resolution data can be used to correlate deformations of internal structure with changes in mobility. This low cost solution provides users with an automated approach to obtain high-resolution images and mobility statistics of C. elegans.
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- 2017
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26. Variation in timing of ossification affects inferred heterochrony of cranial bones in Lissamphibia
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Christopher A, Sheil, Michael, Jorgensen, Frank, Tulenko, and Sean, Harrington
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Amphibians ,Time Factors ,Osteogenesis ,Skull ,Animals - Abstract
The evolutionary origin of Lissamphibia likely involved heterochrony, as demonstrated by the biphasic lifestyles of most extant orders, differences between Anura (with tadpole-to-froglet metamorphosis) and Urodela (which lack strongly defined metamorphosis), and the appearance of direct development among separate lineages of frogs. Patterns in the timing of appearance of skeletal elements (i.e., ossification sequence data) represent a possible source of information for understanding the origin of Lissamphibia, and with the advent of analytical methods to directly optimize these data onto known phylogenies, there has been a renewed interest in assessing the role of changes in these developmental events. However, little attention has been given to the potential impact of variation in ossification sequence data--this is particularly surprising given that different criteria for collecting these data have been employed. Herein, new and previously published ossification data are compiled and all pairs of data for same-species comparisons are selected. Analyses are run to assess the impact of using data that were collected by different methodologies: (1) wild- versus lab-raised animals; (2) different criteria for recognizing timing of ossification; and (3) randomly selecting ossification sequences for species from which multiple studies have been published, but for which the data were collected by different criteria. Parsimov-based genetic inference is utilized to map ossification sequence data onto an existing phylogeny to reconstruct ancestral sequences of ossification and infer instances of heterochrony. All analyses succeeded in optimizing sequence data on internal nodes and instances of heterochrony were identified. However, among all analyses little congruence was found in reconstructed ancestral sequences or among inferred instances of heterochrony. These results indicate a high degree of variation in timing of ossification, and suggest a cautionary note about use of these data, particularly given that in most instances issues associated with the original sources of data (e.g., wild- vs. lab-raised animals; or criteria for identification of earliest ossification) are not addressed. Potential sources of variation in the original data are discussed and may explain the incongruence observed here.
- Published
- 2014
27. How Can Land Tenure and Cadastral Reform Succeed? An Inter-Regional Comparison of Rural Reforms
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Sean Harrington, Buster Davison, Khaleel Khan, Michael Bristow, and Brian Ballantyne
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Economic growth ,Geography ,Economic policy ,Security of tenure ,Cadastre ,Land market ,Development ,Agricultural productivity ,Agrarian reform ,Land tenure ,Natural resource ,Land reform - Abstract
In a synthesis of studies in English, Spanish and French, cadastral reforms in Peru, Colombia, Albania, Hungary, Burkina Faso and Senegal were examined, confirming that rural reforms are successful only if they acknowledge the existence of traditional landholding systems. Comprehensive, well-intentioned measures that are pursued only partially—without commitment from governments to planning and full implementation, and without the necessary support services—generally do not succeed. The studied reforms were successful only in: consolidating and registering customary tenure, and in promoting the conservation of natural resources. They were neither successful in increasing security of tenure; promoting improvements to land; facilitating access to credit, nor creating a viable land market. Mixed results were obtained in reducing land disputes, increasing agricultural production, and reducing fragmented holdings.
- Published
- 2000
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28. Challenges of Sustaining the International Space Station through 2020 and Beyond: Including Epistemic Uncertainty in Reassessing Confidence Targets
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Leif Anderson, David Jackson, Katrina Carter-Journet, Sean Harrington, Neil Box, Denise DiFilippo, and Michael Lutomski
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Bayes' theorem ,Engineering ,Operations research ,business.industry ,Reliability (computer networking) ,Spare part ,International Space Station ,Survivability ,Failure rate ,Uncertainty quantification ,business ,Confidence interval - Abstract
This paper introduces an analytical approach, Probability and Confidence Trade-space (PACT), which can be used to assess uncertainty in International Space Station (ISS) hardware sparing necessary to extend the life of the vehicle. There are several key areas under consideration in this research. We investigate what sparing confidence targets may be reasonable to ensure vehicle survivability and for completion of science on the ISS. The results of the analysis will provide a methodological basis for reassessing vehicle subsystem confidence targets. An ongoing annual analysis currently compares the probability of existing spares exceeding the total expected unit demand of the Orbital Replacement Unit (ORU) in functional hierarchies approximating the vehicle subsystems. In cases where the functional hierarchies availability does not meet subsystem confidence targets, the current sparing analysis further identifies which ORUs may require additional spares to extend the life of the ISS. The resulting probability is dependent upon hardware reliability estimates. However, the ISS hardware fleet carries considerable epistemic uncertainty (uncertainty in the knowledge of the true hardware failure rate), which does not currently factor into the annual sparing analysis. The existing confidence targets may be conservative. This paper will also discuss how confidence targets may be relaxed based on the inclusion of epistemic uncertainty for each ORU. The paper will conclude with strengths and limitations for implementing the analytical approach in sustaining the ISS through end of life, 2020 and beyond.
- Published
- 2012
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29. Learning As We Go: A First Snapshot of Early Head Start Programs, Staff, Families, and Children. Volume II: Technical Appendices
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Cheri A. Vogel, Kimberly Boller, Yange Xue, Randall Blair, Nikki Aikens, Andrew Burwick, Yevgeny Shrago, Barbara Lepidus Carlson, Laura Kalb, Linda Mendenko, Judith Cannon, Sean Harrington, and Jillian Stein
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Early Head Start , Baby FACES , Early Childhood ,jel:I - Published
- 2011
30. Learning As We Go: A First Snapshot of Early Head Start Programs, Staff, Families, and Children. Volume I
- Author
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Cheri A. Vogel, Kimberly Boller, Yange Xue, Randall Blair, Nikki Aikens, Andrew Burwick, Yevgeny Shrago, Barbara Lepidus Carlson, Laura Kalb, Linda Mendenko, Judith Cannon, Sean Harrington, and Jillian Stein
- Subjects
Early Head Start , Baby FACES , Early Childhood ,jel:I - Abstract
The Early Head Start Family and Child Experiences Survey, or Baby FACES, is a longitudinal descriptive study of Early Head Start that captures family- and child-level information in addition to program-level characteristics. This first report defines Head Start features and characteristics, program services and delivery, characteristics of Early Head Start families, characteristics of special populations and subgroups, and the psychometric properties of the survey measures.
- Published
- 2011
31. Improving the Estimates of International Space Station (ISS) Induced 'K-Factor' Failure Rates for On-Orbit Replacement Unit (ORU) Supportability Analyses
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Ojei Omeke, Douglas G. Schwaab, Leif Anderson, and Sean Harrington
- Subjects
Engineering ,business.industry ,International Space Station ,Associated function ,Leverage (statistics) ,business ,Engineering analysis ,Reliability engineering - Abstract
This is a case study on revised estimates of induced failure for International Space Station (ISS) on-orbit replacement units (ORUs). We devise a heuristic to leverage operational experience data by aggregating ORU, associated function (vehicle sub -system), and vehicle effective' k-factors using actual failure experience. With this input, we determine a significant failure threshold and minimize the difference between the actual and predicted failure rates. We conclude with a discussion on both qualitative and quantitative improvements the heuristic methods and potential benefits to ISS supportability engineering analysis.
- Published
- 2009
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32. Book Reviews
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Sean Harrington
- Subjects
Social Psychology ,Social Sciences (miscellaneous) - Published
- 1996
- Full Text
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