225 research outputs found
Prédiction de gÚnes parallélisée de haute performance dans MATLAB
Ce travail sâinscrit dans un cadre de recherche global du gĂ©nome humain. Il s'intĂ©resse particuliĂšrement Ă l'identification de milliers de gĂšnes qui demeurent toujours inconnus Ă ce jour. Afin de pouvoir effectuer cette tĂąche sur une plateforme informatique, les sĂ©quences dâacide dĂ©soxyribonuclĂ©ique (ADN) seront traitĂ©es comme Ă©tant des signaux pour permettre lâusage des techniques en traitement numĂ©rique de signaux (TNS). Cette approche permettra de rĂ©duire les coĂ»ts et surtout, le temps que prennent les chercheurs Ă trouver un gĂšne impliquĂ© dans une maladie. Le projet est divisĂ© en deux volets. Le premier volet de cette recherche consiste Ă rĂ©duire de façon importante les temps de calcul de certains algorithmes en bio-informatique. Cette recherche propose une mĂ©thode de mise en oeuvre des algorithmes de prĂ©diction de gĂšnes en parallĂšle avec le logiciel MATLAB. Les approches proposĂ©es sont basĂ©es soit sur lâalgorithme de Goertzel ou de FFT en utilisant diverses procĂ©dures de parallĂ©lisme sur une unitĂ© centrale de traitement (CPU) et Ă une unitĂ© de processeur graphique (GPU). Les rĂ©sultats montrent que lâutilisation dâune approche simple, câest-Ă -dire sans modification de lâimplĂ©mentation dans MATLAB, peut nĂ©cessiter plus de 4 h et demie pour le traitement de 15 millions de paires de bases (pb) alors quâune implĂ©mentation optimisĂ©e peut effectuer la mĂȘme tĂąche en moins dâune minute. Nous avons obtenu les meilleurs rĂ©sultats avec lâimplĂ©mentation sur GPU qui a pu complĂ©ter l'analyse en 57 s, ce qui est plus de 270 fois plus rapide quâune approche conventionnelle. Ce premier volet de recherche propose deux stratĂ©gies pour accĂ©lĂ©rer le traitement des donnĂ©es du gĂ©nome humain et sâappuie sur les diffĂ©rents mĂ©canismes de parallĂ©lisation. Lorsque l'implantation se fait avec un CPU, les rĂ©sultats indiquent qu'il serait prĂ©fĂ©rable d'utiliser une fonction de bas niveau (MEX) afin d'augmenter la vitesse dâexĂ©cution. De plus, l'usage des boucles parallĂšles (PARFOR) doit ĂȘtre effectuĂ© dans un ordre prĂ©cis pour bĂ©nĂ©ficier au maximum du parallĂ©lisme dans lâimplantation de Goertzel. Lorsque l'implantation est exĂ©cutĂ©e sur le GPU, les donnĂ©es doivent ĂȘtre segmentĂ©es en plus petits blocs afin d'optimiser les temps de traitement. En effet, les blocs qui sont trop gros risquaient de dĂ©passer la taille de la mĂ©moire tandis que des blocs trop petits ne permettaient pas Ă l'usager de bĂ©nĂ©ficier pleinement du parallĂ©lisme. Dans le second volet, nous avons poursuivi avec lâimplantation dâun second algorithme qui permet de cibler les rĂ©gions susceptibles Ă la prĂ©sence de gĂšnes. Cet algorithme se base sur les hexamĂšres qui sont de courtes sĂ©quences dâADN composĂ©es de 6 nuclĂ©otides. De toutes les variations dâhexamĂšres possibles (4096), seulement 40 de celles-ci se retrouvent plus souvent dans les rĂ©gions codantes que non codantes. Les autres hexamĂšres se retrouvent autant dans les introns que dans les exons. Il est donc possible de survoler les sĂ©quences dâADN et, selon la prĂ©sence ou lâabsence de certains hexamĂšres, de prĂ©dire quelles rĂ©gions sont codantes. Lors de la superposition des deux approches, soit lâanalyse en frĂ©quence et lâanalyse des hexamĂšres, il est possible de mieux cibler les zones oĂč lâon peut retrouver de nouveaux gĂšnes. Les analyses effectuĂ©es avec les diffĂ©rents algorithmes prĂ©sentent des valeurs qui tĂ©moignent de la probabilitĂ© de retrouver un gĂšne dans une rĂ©gion donnĂ©e. Pour complĂ©ter le processus de prĂ©diction, il est important de dĂ©terminer un critĂšre Ă partir duquel le programme dĂ©cide quâil sâagit rĂ©ellement dâun gĂšne. Ce critĂšre est basĂ© sur trois paramĂštres, soient le seuil positif, le seuil nĂ©gatif et taille de la fenĂȘtre. Afin de dĂ©terminer les valeurs optimales, les trois paramĂštres ont Ă©tĂ© balayĂ©s et la meilleure combinaison a Ă©tĂ© identifiĂ©e. Lâapproche proposĂ©e dans ce mĂ©moire permet dâanalyser de grandes sĂ©quences dâADN en peu de temps afin dâidentifier des zones susceptibles de coder un gĂšne. Ce processus est important puisquâon estime quâil reste encore quelques milliers de gĂšnes inconnus qui peuvent ĂȘtre responsables de plusieurs maladies gĂ©nĂ©tiques. Nous espĂ©rons que ce travail contribuera Ă la dĂ©couverte de nouveaux gĂšnes pour ainsi mieux diagnostiquer certaines maladies gĂ©nĂ©tiques
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The MEK2-binding tumor suppressor hDlg is recruited by E-cadherin to the midbody ring
Background: The human homologue of the Drosophila Discs-large tumor suppressor protein, hDlg, is a multi-domain cytoplasmic protein that localizes to the membrane at intercellular junction sites. At both synaptic junctions and epithelia cell-cell junctions, hDlg is known to recruit several signaling proteins into macromolecular complexes. hDlg is also found at the midbody, a small microtubule-rich structure bridging the two daughter cells during cytokinesis, but its function at this site is not clear. Results: Here we describe the interaction of hDlg with the activated form of MEK2 of the canonical RAF/MEK/ERK pathway, a protein that is found at the midbody during cytokinesis. We show that both proteins localize to a sub-structure of the midbody, the midbody ring, and that the interaction between the PDZ domains of hDlg and the C-terminal portion of MEK2 is dependent on the phosphorylation of MEK2. Finally, we found that E-cadherin also localizes to the midbody and that its expression is required for the isoform-specific recruitment of hDlg, but not activated MEK2, to that structure. Conclusion: Our results suggest that like at other cell-cell junction sites, hDlg is part of a macromolecular complex of structural and signaling proteins at the midbody.Molecular and Cellular Biolog
Representation of Objects in Space by Two Classes of Hippocampal Pyramidal Cells
Humans can recognize and navigate in a room when its contents have been rearranged. Rats also adapt rapidly to movements of objects in a familiar environment. We therefore set out to investigate the neural machinery that underlies this capacity by further investigating the place cellâbased map of the surroundings found in the rat hippocampus. We recorded from single CA1 pyramidal cells as rats foraged for food in a cylindrical arena (the room) containing a tall barrier (the furniture). Our main finding is a new class of cells that signal proximity to the barrier. If the barrier is fixed in position, these cells appear to be ordinary place cells. When, however, the barrier is moved, their activity moves equally and thereby conveys information about the barrier's position relative to the arena. When the barrier is removed, such cells stop firing, further suggesting they represent the barrier. Finally, if the barrier is put into a different arena where place cell activity is changed beyond recognition (âremappingâ), these cells continue to discharge at the barrier. We also saw, in addition to barrier cells and place cells, a small number of cells whose activity seemed to require the barrier to be in a specific place in the environment. We conclude that barrier cells represent the location of the barrier in an environment-specific, place cell framework. The combined place + barrier cell activity thus mimics the current arrangement of the environment in an unexpectedly realistic fashion
The interaction of lean and building information modeling in construction
Lean construction and Building Information Modeling are quite different initiatives, but both are having profound impacts on the construction industry. A rigorous analysis of the myriad specific interactions between them indicates that a synergy exists which, if properly understood in theoretical terms, can be exploited to improve construction processes beyond the degree to which it might be improved by application of either of these paradigms independently. Using a matrix that juxtaposes BIM functionalities with prescriptive lean construction principles, fifty-six interactions have been identified, all but four of which represent constructive interaction. Although evidence for the majority of these has been found, the matrix is not considered complete, but rather a framework for research to
explore the degree of validity of the interactions. Construction executives, managers, designers and developers of IT systems for construction can also benefit from the framework as an aid to recognizing the potential synergies when planning their lean and BIM adoption strategies
Bostonia
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
Synthetic anionic surfaces can replace microparticles in stimulating burst coagulation of blood plasma
Biomaterials are frequently evaluated for pro-coagulant activity but usually in the presence of microparticles (MPs), cell-derived vesicles in blood plasma whose phospholipid surfaces allow coagulation factors to set up as functional assemblies. We tested the hypothesis that synthetic anionic surfaces can catalyze burst thrombin activation in human blood plasma in the absence of MPs. In a thromboelastography (TEG) assay with plastic sample cups and pins, recalcified human citrated platelet-poor plasma spontaneously burst-coagulated but with an unpredictable clotting time whereas plasma depleted of MPs by ultracentrifugation failed to coagulate. Coagulation of MP-depleted plasma was restored in a dose-dependent manner by glass microbeads, hydroxyapatite nanoparticles (HA NPs), and carboxylic acid-containing anionic nanocoatings of TEG cups and pins (coated by glow-discharge plasma-polymerized ethylene containing oxygen, L-PPE:O with 4.4 and 6.8 atomic % [COOH]). Glass beads lost their pro-coagulant activity in MP-depleted plasma after their surfaces were nanocoated with hydrophobic plasma-polymerized hexamethyl disiloxane (PP-HMDSO). In FXII-depleted MP-depleted plasma, glass microbeads failed to induce coagulation, however, FXIa was sufficient to induce coagulation in a dose-dependent manner, with no effect of glass beads. These data suggest that anionic surfaces of crystalline, organic, and amorphous solid synthetic materials catalyze explosive thrombin generation in MP-depleted plasma by activating the FXII-dependent intrinsic contact pathway. The data also show that microparticles are pro-coagulant surfaces whose activity has been largely overlooked in many coagulation studies to-date. These results suggest a possible mechanism by which anionic biomaterial surfaces induce bone healing by contact osteogenesis, through fibrin clot formation in the absence of platelet activation.Fil: Contreras GarcĂa, Angel. Ăcole Polytechnique de MontrĂ©al. Department of Engineering Physics. Groupe de Physique et Technologie des Couches Minces; CanadĂĄFil: D'elĂa, Noelia Laura. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de QuĂmica del Sur. Universidad Nacional del Sur. Departamento de QuĂmica. Instituto de QuĂmica del Sur; Argentina. Ăcole Polytechnique de MontrĂ©al. Department of Engineering Physics; CanadĂĄFil: DesgagnĂ©, Maxime. Ăcole Polytechnique de MontrĂ©al. Department of Engineering Physics; CanadĂĄFil: Lafantaisie Favreau, Charles Hubert. Ăcole Polytechnique de MontrĂ©al. Department of Engineering Physics; CanadĂĄFil: Rivard, Georges Ătienne. CHU Sainte-Justine; CanadĂĄFil: Ruiz, Juan Carlos. Universidad AutĂłnoma Metropolitana; MĂ©xicoFil: Wertheimer, Michael Robert. Ăcole Polytechnique de MontrĂ©al. Department of Engineering Physics. Groupe de Physique et Technologie des Couches Minces; CanadĂĄ. Ăcole Polytechnique de MontrĂ©al. Institute of Biomedical Engineering; CanadĂĄFil: Messina, Paula VerĂłnica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - BahĂa Blanca. Instituto de QuĂmica del Sur. Universidad Nacional del Sur. Departamento de QuĂmica. Instituto de QuĂmica del Sur; ArgentinaFil: Hoemann, Caroline Dieckmann. Ăcole Polytechnique de MontrĂ©al. Department of Engineering Physics; CanadĂĄ. Ăcole Polytechnique de MontrĂ©al. Institute of Biomedical Engineering; Canad
Kloning Manusia
In the last few years, very rapid progress in the cloning technology and its development towards human cloning has become a hotly-debated issue. Cloning, which is the process of formation of a number of individuals with the same genetic structure, can be done by means of embryo-splitting method and nuclear transfer. Human cloning through the nuclear transfer method is directed towards two purposes, i.e. reproduction and therapy. The relatively new transgenic technology can be combined with the cloning technique to produce clones with new genes. However, pros and cons arise concerning the development of research on human cloning, particularly cloning for reproductive purposes. Therefore, there is need for a moratorium period before human cloning can be performed in order that solutions for all kinds of problems related to safety and ethics can be found
NHCâStabilized Mixed Group 13/14/15 Element Hydrides
The syntheses of novel N-heterocyclic carbene (NHC) adducts of group 13, 14 and 15 element hydrides are reported. Salt metathesis reactions between NaPH2 and IDippââ
âGeH2BH2OTf (1) (IDipp=1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) led to mixtures of the two isomers IDippââ
âGeH2BH2PH2 (2âa) and IDippââ
âBH2GeH2PH2 (2âb); by altering the reaction conditions an almost exclusive formation of 2âb was achieved. Attempts to purify mixtures of 2âa and 2âb by re-crystallization from THF afforded a salt [IDippââ
âGeH2BH2ââ
âIDipp][PHGeH2BH2PH2BH2GeH2] (4) that contains the novel anionic cyclohexyl-like inorganic heterocycle [PHGeH2BH2PH2BH2GeH2]â. In addition, the borane adducts IDippââ
âGeH2BH2PH2BH3 (3âa) and IDippââ
âBH2GeH2PH2BH3 (3âb) as even longer chain compounds were obtained from reactions of 2âa/2âb with H3Bââ
âSMe2 and were studied by NMR spectroscopy. Accompanying DFT computations give insight into the mechanism and energetics associated with 2âa/2âb isomerization as well as their decomposition pathways
Le FORUM, Vol. 35 No. 2
https://digitalcommons.library.umaine.edu/francoamericain_forum/1030/thumbnail.jp
Land-based measures to mitigate climate change : potential and feasibility by country
Acknowledgements The design of this study and the data generated was guided by expert consultations and relied on the help of many. We thank all those who contributed: Sierra Gladfelter, Jo House, Mercedes Bustamante, Susan Cook-Patton, Sara Leavitt, Nick Wolff, and Thomas Worthington. We thank M.-J. Valentino at Imaginary Office for helping to design the first three figures. This work was supported by the authorsâ institutions and funding sources, including the Climate and Land-use Alliance, the Dutch Ministry of Agriculture, Nature Management and Food Quality, and the EU H2020 projects VERIFY and ENGAGE (grant agreement no. 821471).Peer reviewedPublisher PD
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