934 research outputs found

    PLANT: A Method for Detecting Changes of Slope in Noisy Trajectories

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    Time traces obtained from a variety of biophysical experiments contain valuable information on underlying processes occurring at the molecular level. Accurate quantification of these data can help explain the details of the complex dynamics of biological systems. Here, we describe PLANT (Piecewise Linear Approximation of Noisy Trajectories), a segmentation algorithm that allows the reconstruction of time-trace data with constant noise as consecutive straight lines, from which changes of slopes and their respective durations can be extracted. We present a general description of the algorithm and perform extensive simulations to characterize its strengths and limitations, providing a rationale for the performance of the algorithm in the different conditions tested. We further apply the algorithm to experimental data obtained from tracking the centroid position of lymphocytes migrating under the effect of a laminar flow and from single myosin molecules interacting with actin in a dual-trap force-clamp configuration.The authors gratefully acknowledge financial support fromthe European Commission (FP7-ICT-2011-7, grant number 288263), Erasmus Mundus Doctorate Program Europhoton-ics (grant number 159224-1-2009-1-FR-ERA MUNDUS-EMJD), Spanish Ministry of Economy and Competi-tiveness (“Severo Ochoa” Programme for Centres of Excellence in Research & Development SEV-2015-0522,and FIS2014-56107-R grants), Generalitat de Catalunyathrough the CERCA program, Italian Ministry of Uni-versity and Research (FIRB “Futuro in Ricerca” 2013grant n. RBFR13V4M2 and Flagship Project NANOMAX),Fundaci ́o Privada CELLEX (Barcelona), Ente Cassa diRisparmio di Firenze, Human Frontier Science Program (GARGP0027/2012) and LaserLab Europe 4 (GA 654148). C.M.acknowledges funding from the Spanish Ministry of Econ-omy and Competitiveness (MINECO) and the EuropeanSocial Fund (ESF) through the Ram ́on y Cajal program 2015(RYC-2015-17896).Peer ReviewedPostprint (author's final draft

    MAPS-SNMA ShaD.O.w D.O. Day Rowan SOM Pipeline Program: A Pilot Study

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    Prior to being a medical student, a majority of pre-medical students have not encountered the course load intensity, academic rigor, and time management required by a medical school curriculum. Diversifying the workforce has been shown to have benefits, especially at the micro or patient level, since having racial or ethnic concordance between providers and patients has been associated with increased levels of satisfaction and improvements in certain clinical outcomes. The number of MDs increased to 841,321 or 91.8% versus 72,961 DOs or 8.0% creating the need for minorities to be knowledgeable of both MD and DO paths to becoming a physician. To provide more knowledge of osteopathic medicine and osteopathic physicians, the Minority Association of Premedical Students (M.A.P.S.) and the the Student National Medical Association (S.N.M.A.) of Rowan University School of Osteopathic Medicine have implemented a ShaDOw DO Day program for the graduate students of Rowan University Graduate School of Biomedical Sciences. The ShaDOw DO Day program will give MAPS students the opportunity to witness the resilience, discipline, and motivation that successful medical students possess.This program will also provide MAPS students with the opportunity to explore a potential career in medicine. Students will gain a perspective on osteopathic principles and osteopathic manipulative medicine. Participants of the program will also be introduced to the quality education an osteopathic medical school such as RowanSOM instills in its students to produce competent and compassionate physicians. Therefore, it is imperative that graduate students learn from medical students to increase their knowledge of osteopathic medicine. To analyze the effectiveness of this program, pre-assessment and post-assessment surveys were given to the participants. Overall, an increase in the understanding of osteopathic medicine and consideration of a career in a health profession and/or medicine was observed demonstrating both the need and success of our program initiative

    Genetic Polymorphism in Evolving Population

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    We present a model for evolving population which maintains genetic polymorphism. By introducing random mutation in the model population at a constant rate, we observe that the population does not become extinct but survives, keeping diversity in the gene pool under abrupt environmental changes. The model provides reasonable estimates for the proportions of polymorphic and heterozygous loci and for the mutation rate, as observed in nature

    Controlling the balance between remote, pinhole, and van der Waals epitaxy of Heusler films on graphene/sapphire

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    Remote epitaxy on monolayer graphene is promising for synthesis of highly lattice mismatched materials, exfoliation of free-standing membranes, and re-use of expensive substrates. However, clear experimental evidence of a remote mechanism remains elusive. In many cases, due to contaminants at the transferred graphene/substrate interface, alternative mechanisms such as pinhole-seeded lateral epitaxy or van der Waals epitaxy can explain the resulting exfoliatable single-crystalline films. Here, we find that growth of the Heusler compound GdPtSb on clean graphene on sapphire substrates produces a 30 degree rotated epitaxial superstructure that cannot be explained by pinhole or van der Waals epitaxy. With decreasing growth temperature the volume fraction of this 30 degree domain increases compared to the direct epitaxial 0 degree domain, which we attribute to slower surface diffusion at low temperature that favors remote epitaxy, compared to faster surface diffusion at high temperature that favors pinhole epitaxy. We further show that careful graphene/substrate annealing (T700CT\sim 700 ^\circ C) and consideration of the film/substrate vs film/graphene lattice mismatch are required to obtain epitaxy to the underlying substrate for a variety of other Heusler films, including LaPtSb and GdAuGe. The 30 degree rotated superstructure provides a possible experimental fingerprint of remote epitaxy since it is inconsistent with the leading alternative mechanisms

    Interrogation of an Enzyme Library Reveals the Catalytic Plasticity of Naturally Evolved [4+2] Cyclases

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    \ua9 2023 The Authors. ChemBioChem published by Wiley-VCH GmbH.Stereoselective carbon-carbon bond forming reactions are quintessential transformations in organic synthesis. One example is the Diels-Alder reaction, a [4+2] cycloaddition between a conjugated diene and a dienophile to form cyclohexenes. The development of biocatalysts for this reaction is paramount for unlocking sustainable routes to a plethora of important molecules. To obtain a comprehensive understanding of naturally evolved [4+2] cyclases, and to identify hitherto uncharacterised biocatalysts for this reaction, we constructed a library comprising forty-five enzymes with reported or predicted [4+2] cycloaddition activity. Thirty-one library members were successfully produced in recombinant form. In vitro assays employing a synthetic substrate incorporating a diene and a dienophile revealed broad-ranging cycloaddition activity amongst these polypeptides. The hypothetical protein Cyc15 was found to catalyse an intramolecular cycloaddition to generate a novel spirotetronate. The crystal structure of this enzyme, along with docking studies, establishes the basis for stereoselectivity in Cyc15, as compared to other spirotetronate cyclases
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