Letteratura scientifica selezionata sul tema "Manipulation de laboratoire"
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Articoli di riviste sul tema "Manipulation de laboratoire":
1
Chaigneau, D., M. Arsicault, J. P. Gazeau e S. Zeghloul. "LMS robotic hand grasp and manipulation planning (an isomorphic exoskeleton approach)". Robotica 26, n. 2 (marzo 2008): 177–88. http://dx.doi.org/10.1017/s0263574707003736.
Abstract (sommario):
SUMMARYIn order to widen the potentialities of manipulation of the Laboratoire de Mécanique des solides (LMS) mechanical hand, we developed a new planning approach based on the use of a specific exoskeleton. This one has kinematics architecture and dimensions identical to the mechanical hand. This feature allows us to obtain manipulation trajectories for the mechanical hand, very easily and very quickly, by using the exoskeleton, without complex calibration. Manipulation's trajectories are replayed offline with an autonomous control, and, consequently, the exoskeleton is not used with any feedback strategy for telemanipulation. This paper presents the characteristics of this exoskeleton and the graphic interface that we developed. This one uses a method to determine the object's evolution during the manipulation with the exoskeleton, without using exteroceptive sensors. This new approach was tested for standard trajectories by simulation on a Computer-aided design (CAD) robotics system and by using the mechanical hand. Thus, we validate the use concept of an isomorphic exoskeleton to mechanical hand for manipulation planning with the LMS mechanical hand.
2
Sylvie TOUCHE e Dominique ABITEBOUL. "SÉCURITÉ AU LABORATOIRE DE BACTÉRIOLOGIE CLINIQUE". ACTUALITES PERMANENTES EN MICROBIOLOGIE CLINIQUE 18, n. 01 (1 marzo 2019): 10. http://dx.doi.org/10.54695/apmc.18.01.1506.
Abstract (sommario):
L’activité des laboratoires de biologie médicale (LBM) imposeaux professionnels qui y exercent de se prémunir vis-à-vis d’uncertain nombre de risques, pour leur propre protection et celle deleur environnement.S’agissant des laboratoires de bactériologie, le risque microbiologique occupe une place évidente. D’autres risques sont aussià prendre en considération, tels que ceux liés à la manipulation deproduits chimiques de divers types, à l’utilisation d’appareillages,aux postures contraintes dans certaines situations de travail, …L’ensemble de ces risques doit faire l’objet d’une évaluation(EvRP) dans le cadre de l’obligation réglementaire qui incombeà tout employeur (art. L.4121-2 et L.4121-3 du Code du travail).Cette évaluation doit être élaborée en concertation avec l’ensembledes professionnels concernés. Les résultats, consignés dans un« document unique » (DU), permettent de définir un plan deprévention, régulièrement actualisé en fonction de l’évolutiondes pratiques et des moyens de maîtrise des risques mis en œuvre
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Desrosiers, G., B. Vincent, C. Retière e L. Boucher. "Comparaison de critères utilisables pour l'étude de la structure des populations du polychète Nereis virens (Sars)". Canadian Journal of Zoology 66, n. 6 (1 giugno 1988): 1454–59. http://dx.doi.org/10.1139/z88-212.
Abstract (sommario):
The various biometrical criteria used in the study of the population structure of the annelid polychaete Nereis virens (Sars) are reviewed. This type of study, which requires the examination of large numbers of specimens representing all size classes, is sometimes complicated by the occurrence of autotomy, a phenomenon quite frequent in this species, and by mechanical breaks during sampling and sieving. Measurements such as total length, width of an anterior segment, and total weight are not good criteria. We have used a new biometrical criterium developed at the Laboratoire maritime de Dinard (France). This criterium is based on a partial weight of animals that have been put in formaldehyde and wiped; the weight is determined from an histogram in which breaking points are "ranked". This ponderal measurement has been compared with the linear measurement of the jaw length. The new method allows the manipulation of a larger number of individuals and it is easier and faster to use than the method based on jaw measurements.[Journal translation]
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Barnat, Ons. "Le studio d’enregistrement comme terrain en ethnomusicologie". Ethnologies 37, n. 2 (18 ottobre 2017): 185–206. http://dx.doi.org/10.7202/1041493ar.
Abstract (sommario):
À partir des conclusions tirées de notre thèse (consacrée à l’étude du phénomène de l’enregistrement en studio de la paranda garifuna en Amérique centrale), cet article soulève certaines des préoccupations théoriques et méthodologiques qui apparaissent quand l’ethnomusicologue contemporain décide de faire du studio d’enregistrement son principal terrain de recherche. Dans ces studios où se créent les musiques à vendre, des relations de pouvoir se déploient en permanence autour d’un enjeu principal : le contrôle de la manipulation électronique des sons enregistrés. S’il fait office de laboratoire expérimental pour ses acteurs (musiciens, ingénieurs du son, réalisateurs…), le studio d’enregistrement offre à la recherche ethnomusicologique un microcosme au sein duquel un appareillage technique sophistiqué se trouve manipulé en fonction d’interactions entre des individus. En se basant sur une revue de littérature interdisciplinaire, cet article propose une base théorique et méthodologique pour toute recherche ethnomusicologique portant sur le rôle et la place du studio d’enregistrement dans l’analyse de phénomènes musicaux contemporains.
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Vulliez, P., J. P. Gazeau, P. Laguillaumie, H. Mnyusiwalla e P. Seguin. "Focus on the mechatronics design of a new dexterous robotic hand for inside hand manipulation". Robotica 36, n. 8 (8 maggio 2018): 1206–24. http://dx.doi.org/10.1017/s0263574718000346.
Abstract (sommario):
SUMMARYThis paper presents a novel tendon-driven bio-inspired robotic hand design for in-hand manipulation. Many dexterous robot hands are able to produce adaptive grasping, but only a few human-sized hands worldwide are able to produce fine motions of the object in the hand. One of the challenges for the near future is to develop human-sized robot hands with human dexterity. Most of the existing hands considered in the literature suffer from dry friction which creates unwanted backlash and non-linearities. These problems limit the accurate control of the fingers and the capabilities of the hand. Such was the case with our first fully actuated dexterous robot hand: the Laboratoire de Mécanique des Solides (LMS) hand.The mechanical design of the hand relies on a tendon-based transmission system. Developing a fully actuated dexterous robot hand requires the routing of the tendons through the finger for the actuation of each joint. This paper focuses on the evolution of the tendon routing; from the LMS hand to the new RoBioSS dexterous hand. The motion transmission in the new design creates purely linear coupling relations between joints and actuators. Experimental results using the same protocol for the previous hand and the new hand illustrate the evolution in the quality of the mechanical design. With the improvements of the mechanical behavior of the robotic fingers, the hand control software could be extensively simplified. The choice of a common architecture for all fingers makes it possible to consider the hand as a collaboration of four serial robots. Moreover, with the transparency of the motor-joint transmissions, we could use robust, industrial-grade cascaded feedback loops for the axis controls.An inside-hand manipulation task concerning the manipulation of a bottle cap is presented at the end of the paper. As proof of the robustness of the hand, demonstrations of the hand's capabilities were carried out continuously over three days at SPS IPC Drives international exhibition in Nuremberg, in November 2016.
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Abouhilal, Abdelmoula, Amine Moulay Taj, Naima Taifi e Abdessamad Malaoui. "Using Online Remote Laboratory in Agriculture Engineering and Electronic Training". International Journal of Online and Biomedical Engineering (iJOE) 15, n. 06 (29 marzo 2019): 66. http://dx.doi.org/10.3991/ijoe.v15i06.9699.
Abstract (sommario):
<p class="0abstract">Practical manipulations are a core part of engineering training education systems. Remote labs are a new method used for teaching and practicing experimental manipulation using the performance of information and communication technologies. This paper presents a study of two remote labs architecture using low cost embedded systems that could be addressed to the 3rd year bachelor degree students on renewable energy and others on electronics courses. The first manipulation is based on Arduino microcontroller to monitor an irrigation system powered by photovoltaic panels. In addition, the second manipulation uses a powerful PcDuino, to control remotely a logic electronic experience. A simple interface is developed to allow students and instructors to access to these manipulations. This study is aimed to improve the present education systems in the Moroccan universities by managing the practical manipulation for a large number of students, especially in the open-access faculties. Finally, this architecture can be easily extended to other disciplines and courses.</p>
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Schmitt, A., e B. Bizot. "Retour d'expériences sur l'étude de trois assemblages osseux issus de sépultures collectives néolithiques". Bulletins et Mémoires de la Société d'Anthropologie de Paris 28, n. 3-4 (29 marzo 2016): 190–201. http://dx.doi.org/10.1007/s13219-016-0156-7.
Abstract (sommario):
La plupart des sépultures collectives du Néolithique final ayant bénéficié de fouilles et d'un enregistrement optimaux ont livré une grande quantité d'ossements. Le croisement des données archéologiques et anthropologiques acquises sur le terrain et en laboratoire permet, en théorie, de restituer les pratiques mortuaires. L'investissement en temps et les compétences requises pour l'étude des assemblages osseux issus des sépultures collectives, notamment en contexte préventif, impose d'aborder la question du bilan des travaux. Cette réflexion se base essentiellement sur trois sépultures collectives. La reconstitution des modes de dépôts initiaux des individus et de manipulation des ossements s'est avérée relativement limitée. Faute de pouvoir quantifier les impacts des facteurs taphonomiques ou de conservation différentielle, variables d'un site à l'autre, il reste difficile de choisir parmi les différentsscenariienvisagés. Alors que les méthodes précises mises en œuvre garantissent une acquisition optimale des données lors de la phase terrain, l'analyse des assemblages osseux demeure une tâche longue et complexe, produisant des résultats de faible portée interprétative. Ainsi, s'il est légitime de nous interroger sur l'adéquation entre les moyens et les résultats obtenus, en l'état actuel de nos ressources méthodologiques, un tel déploiement de moyens constitue encore la principale voie d'approche. Cependant, de meilleurs référentiels ostéologiques et taphonomiques sont nécessaires.
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Gouzi, Fares, François Bughin, Lucie Barateau, Agathe Hubert, Savine Volland, Dalila Laoudj-Chenivesse, Emilie Passerieux et al. "Utilisation d’outils numériques dans le cadre d’un dispositif hybride pour l’apprentissage par problème de la physiologie en deuxième année des études médicales. Étude de faisabilité du recours au laboratoire numérique de physiologie « e-ϕsioLab »." Pédagogie Médicale 19, n. 2 (2018): 77–90. http://dx.doi.org/10.1051/pmed/2019007.
Abstract (sommario):
Contexte : À l’Université de Montpellier, l’enseignement de la physiologie passe par une initiation à la démarche expérimentale, effectuée sous forme d’un apprentissage par problème (APP) au cours d’enseignements dirigés (ED) ou travaux pratiques (TP). Actuellement, les ED/TP de physiologie en 2e année de Diplôme de formation générale en sciences médicales (DFGSM2) posent un problème de faisabilité. But(s) : Nous avons évalué la faisabilité d’un dispositif hybride « Laboratoire numérique de physiologie (e-ϕsioLab) » combinant ED présentiels (EDP) au tableau blanc interactif (TBI) + supports multimédias, et ED dématérialisés (EDD) sur plate-forme pédagogique Moodle, pour la résolution de problèmes de physiologie en DFGSM2. Méthodes : Pour les EDP, nous avons évalué les travaux des étudiants et comparé la participation des étudiants ayant bénéficié de ces ED e-ϕsioLab vs. ED classique. Pour les EDD, nous avons évalué les travaux et la participation des étudiants. Résultats : Les travaux ont révélé que les étudiants avaient effectué les tâches d’apprentissage visées pour l’APP (élaboration d’hypothèses, manipulation de paramètres, interprétation, retour sur problème) à l’aide du dispositif hybride. Durant les EDP, la participation et les échanges entre les étudiants étaient supérieurs aux ED classiques. Etudiants et enseignants ont utilisé les fonctionnalités de l’e-ϕsioLab, permettant la production de travaux originaux et en phase avec les objectifs pédagogiques. Conclusion : Notre dispositif hybride e-ϕsioLab à forte hybridation présentiel/à distance apparaît faisable pour l’APP en physiologie. Son utilisation a révélé une forte participation des étudiants, et poussé à la transformation de l’enseignement de physiologie vers les pédagogies actives.
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Hsieh, Mu-Cheng, e Kuu-Young Young. "Effective manipulation for a multi-DOF robot manipulator in laboratory environments". Journal of the Chinese Institute of Engineers 36, n. 5 (luglio 2013): 566–76. http://dx.doi.org/10.1080/02533839.2012.737112.
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COUROT, M., e P. VOLLAND-NAIL. "Conduite de la reproduction des mammifères domestiques : présent et futur". INRAE Productions Animales 4, n. 1 (5 febbraio 1991): 21–29. http://dx.doi.org/10.20870/productions-animales.1991.4.1.4314.
Abstract (sommario):
Les techniques modernes de reproduction appliquées aux mammifères domestiques ont pour but d’accroître l’efficacité de la production de jeunes dans les conditions choisies par les éleveurs. Cette revue présente les différentes techniques disponibles pour atteindre un tel objectif. Pour les mâles, en plus de l’utilisation de semence par insémination artificielle désormais possible chez toutes les espèces domestiques, l’accent est mis sur deux stratégies : d’une part, distribuer par insémination intra-utérine un petit nombre de spermatozoïdes des meilleurs reproducteurs (sur un plan génétique) à un maximum de femelles avec les plus grandes chances de fécondation, d’autre part, maintenir en permanence les mâles d’espèces saisonnées au maximum de leurs capacités de production spermatique par un régime photopériodique approprié. Pour les femelles, des techniques efficaces de contrôle de l’oestrus et de l’ovulation étant maintenant disponibles pour toutes les espèces domestiques, la reproduction peut être conduite au moment choisi par l’éleveur. Des techniques de reproduction plus complexes ont été développées avec la manipulation des embryons dans le but de diffuser plus largement le haut potentiel génétique des meilleurs reproducteurs. Si le transfert d’embryons est parvenu à un stade de développement commercial, la fécondation in vitro et les techniques de sexage ou de clonage des embryons sont encore au stade des études de laboratoire. Ces techniques sont néanmoins présentées car elles modifieront certainement la pratique de l’élevage dans l’avenir. En vue d’objectifs peut-être plus lointains, la transgenèse est aussi abordée chez les animaux domestiques. Enfin, une brève réflexion prospective évoque plusieurs aspects qui font déjà l’objet de recherches afin de mieux maîtriser ou rendre plus efficace la reproduction animale.
Tesi sul tema "Manipulation de laboratoire":
1
Marbach, Nathalie. "Risques lies a la manipulation du virus de la vaccine dans les laboratoires". Université Louis Pasteur (Strasbourg) (1971-2008), 1992. http://www.theses.fr/1992STR1M099.
2
Rabaud, David. "Manipulation et interaction de micro-bulles sous champ acoustique". Phd thesis, Grenoble, 2010. http://tel.archives-ouvertes.fr/tel-00536932.
Abstract (sommario):
Cette thèse traite de l'action des ondes acoustiques sur des bulles micrométriques excitées à leur fréquence de résonance. En effet, les bulles peuvent être considérées comme des oscillateurs mécaniques et les forces acoustiques à leur résonance, appelées forces de Bjerknes, ont des propriétés non triviales. De plus, les bulles interagissent entre elles par l'émission d'un champ secondaire, menant à leur auto-organisation sur un motif périodique. Ici, les bulles sont confinées dans des microcanaux, elles ne sont pas sphériques et frottent fortement sur les parois. L'étude expérimentale des forces acoustiques (primaire et secondaire) est alors précédée par la modélisation de l'écoulement des bulles, liant la friction sur les parois aux forces externes appliquées. Plusieurs applications aux laboratoires sur puce sont développées, dont le tri en taille, la division asymétrique contrôlée, l'aiguillage automatique à une bifurcation, et la manipulation de goutte.
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Gourbal, Benjamin. "Relations interspécifiques dans le modèle souris BALB/c/Taenia crassiceps. Le "comment" avant le "pourquoi" de la manipulation". Montpellier 2, 2002. http://www.theses.fr/2002MON20078.
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Brun, Mathieu. "Électrodes nanocomposites pour applications en microfluidique". Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00744588.
Abstract (sommario):
Le travail de thèse présenté dans ce manuscrit s'inscrit dans une dynamique d'intégration de matériaux non conventionnels en systèmes microfluidiques. Il vise à démontrer le potentiel du cPDMS, un matériau nanocomposite formé d'une matrice de polydiméthylsiloxane rendu conducteur par l'ajout de nanoparticules de carbone. Compatible avec les procédés technologiques habituels, le cPDMS peut être structuré dans une large gamme d'épaisseurs et de géométries mais présente surtout l'avantage de pouvoir être collé irréversiblement sur verre, PDMS et silicium. Son intégration est parfaitement étanche, rapide à mettre en oeuvre, et très économique. La première partie du manuscrit est consacrée à la caractérisation de ce matériau. Ses propriétés électriques et de surface, pouvant être critiques pour une utilisation en microfluidique, ont été particulièrement étudiées. Les champs électriques offrant de nombreuses possibilités pour réaliser des fonctions clés en microfluidique (détection, séparation, manipulation de fluides ou de particules), nous avons choisi d'évaluer l'intérêt d'électrodes de cPDMS dans deux types d'applications. Les aspects de détection ont d'abord été mis en évidence à l'aide de mesures électrochimiques. Cette méthode a permis à la fois de caractériser la surface du cPDMS tout en validant son utilisation potentielle pour des applications d'analyses électrochimiques. Dans la dernière partie du manuscrit, le matériau a été testé pour la manipulation de particules à travers l'observation de différents phénomènes électrocinétiques. Ceux-ci ont conduit à la mise au point de dispositifs microfluidiques (intégrant des lectrodes de cPDMS) dédiés à la lyse et à l'électrofusion de cellules.
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Riaud, Antoine Jean-Pierre René. "Etude des potentialités offertes par la synthèse de champs d'ondes acoustiques de surface pour l'actionnement de liquides et la manipulation sans contact". Thesis, Ecole centrale de Lille, 2016. http://www.theses.fr/2016ECLI0010/document.
Abstract (sommario):
Lorsque des ondes acoustiques de surface rayonnent dans des fluides, elles provoquent deux effets non linéaires : la pression de radiation et le streaming acoustique. Ces deux effets ont trouvé un grand nombre d’applications pour la microfluidique digitale, la manipulation sans contact et le tri cellulaire. Néanmoins, ces systèmes se heurtent à deux limites. D’une part, chaque application requiert une onde acoustique spécifique : il n’existe pas de dispositif multifonction à ce jour. D’autre part, l’exploration des fonctionnalités offertes par les ondes de surface les plus simples (ondes planes, ondes focalisées) n’a pas permis de réaliser des pinces sélectives permettant de manipuler individuellement des particules ou cellules indépendamment de leurs voisines.Dans une première partie de la thèse, nous développons deux méthodologies pour synthétiser des champs complexes d’ondes de surface. La première méthode utilise un réseau de 32 peignes interdigités contrôlé par la technique du filtre inverse pour générer des champs sur demande. La seconde résout un problème inverse afin de concevoir un transducteur holographique générant spécifiquement le champ demandé. Dans la seconde partie de la thèse, nous utilisons le filtre inverse pour (i) réaliser un laboratoire sur puce multifonction et (ii) étudier le potentiel d’ondes de surface particulières appelées ondes de surface tourbillonnaires. Ces ondes permettent une manipulation sélective et sans contact d’objets microscopiques. Nous terminons la thèse en équipant un microscope d’un transducteur holographique de vortex acoustiques afin de réaliser une manipulation sélective et sans contact de cellulesWhen surface acoustic waves radiate in nearby fluids, they trigger two nonlinear effects: acoustic radiation pressure and acoustic streaming. These two effects find numerous applications for digital microfluidics, contactless manipulation and biological cell sorting. Nonetheless, these systems face two limitations. On the one hand, each application requires a specific acoustic wave: there is no multifunction device so far. On the other hand, search for functionalities offered by simple surface acoustic waves (plane and focused waves) has failed to provide a selective tweezers able to manipulate individual particles or cells independently of their neighbors. In the first part of this thesis, we develop two methods to synthesize complex surface acoustic wave fields. The first one employs an array of 32 interdigitated transducers controlled by the inverse filter to generate arbitrary fields on demand. The second method solves an inverse problem to design a holographic transducer to generate a predefined field. In the second part of the thesis, we use the inverse filter to (i) implement a multifunction lab on a chip and (ii) investigate the potentialities of a special type of surface acoustic waves called swirling surface waves. These waves enable a selective and contactless manipulation of microscopic objects. We conclude the thesis by integrating a holographic acoustical vortex transducer on a microscope in order to selectively manipulate biological cells without contact
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Ehlert, Jannik F. "Optoelectronic characterization and modeling of external cavity semiconductor diode lasers for metrological applications". Electronic Thesis or Diss., Institut polytechnique de Paris, 2022. http://www.theses.fr/2022IPPAT013.
Abstract (sommario):
Les boîtes quantiques sont une technologie performante pour les diodes laser. En changeant la taille et la forme de ces boîtes et en utilisant une facette de sortie antireflet, des puces à gain peuvent être conçues pour émettre sur une large gamme de longueurs d’onde dans des lasers accordables. Cette thèse de doctorat traite à la fois de la simulation d’un laser à cavité externe et de la caractérisation expérimentale d’un laser accordable basé sur une puce à gain à boîte quantique. Un modèle d’équation d’évolution a été développé. La simulation numérique étudie les propriétés dynamiques et de bruit de ce laser. Ce travail montre l’intégration d’une puce à gain à boîte quantique dans une configuration de laser du type Littman-Metcalf. De plus, une nouvelle méthode a été développée pour résoudre spectralement l’émission spontanée en champ lointain de la puce à gain. Un mécanisme de référencement en longueur d’onde utilisant un étalon Fabry-Perot est présenté en détail. Enfin, un prototype d’un nouveau laser accordable à haute puissance sans asservissement a été testé à long terme pour un fonctionnement sans saut de modeQuantum dots have been proven to be a high performing technology for solitary laser diodes. By varying dot sizes, shapes, and by using an antireflection output facet, gain chips can be designed to emit over a large wavelength range in tunable lasers. This PhD thesis work deals with both the simulation of an external cavity laser and the experimental characterization of a quantum dot gain chip-based tunable laser. A rate equation model has been derived. The numerical simulation investigates dynamical properties like turn-on delay, gain clamping and damping rate. This work shows the integration of a quantum dot gain chip in a Littman-Metcalf laser setup. Also, a new method has been developed to spectrally resolve the gain chip’s spontaneous emission in the far-field. A wavelength referencing mechanism utilizing a Fabry- Perot etalon is laid out in detail. Finally, a prototype of a newly developed high power tunable laser without servo control has been tested for long term mode-hop free operation
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Moral, Zamora Beatriz del. "Bioimpedance & dielectrophoresis instrumentation equipments for living cells manipulation and monitoring". Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/395178.
Abstract (sommario):
Since the first microfluidic device was developed in the early 1950s, when the basics for today’s inkjet technology were set, thousands of publications have appeared related to the topic. The increasing interest on these technologies is caused by its ability to be scaled and its rapid development, which allows manipulating and detecting small quantities of analites even at the cellular scale. The integration of microfluidic technologies with specific sensors and actuators at minute scales in order to achieve a set of automated laboratory operations and perform a particular solution for a specific application, generally on the life sciences and chemistry fields, was defined as Lab-on-a-chip (LoC). LoC devices have the potential to become a powerful technology for some fields, such as health, food security or environmental control. Their low cost and portability make them also suitable to improve medical diagnosis and research in developing countries. Moreover, these systems permit also to explore new methods for manipulation and characterization of cells by means of electrical cell properties, by using techniques such as dielectrophoresis (DEP) or impedance spectroscopy (IS). In fact, the dielectrophoretic force allows manipulating cells, taking advantage of their electrical properties, by applying an electric field. Likewise, impedance allows measuring electrical properties of materials and, used wisely, inform about characteristics such as presence, composition or size of cells or other biological materials.
This work aims, in its final stage, to exploit the combined potential of both techniques, DEP and IS, in a compact system for bioanalytical bench-top applications. The creation of the complete device has been a long procedure alternating theoretical calculations and experimental tests. It has included different steps such as the design of the need electronic equipment stages, the study of different microfluidic designs, an accurate bacteria concentration and manipulation protocol definition, and the study of the viability of the bacteria populations recovered with our device. These studies have made possible to finally obtain an automated bacteria concentrator for microbiology, food, water and environmental control applications while performing impedance cell analysis to monitor bacteria accumulation during the process. The system has been adjusted and proved for the real case of Escherichia Coli (E. coli) concentration and analysis. E. coli presents pathogenic variants that cause morbidity and mortality worldwide being therefore a topic of interest. E. coli is one of the main antimicrobials resistant pathogens in healthcare-associated infections reported to the National Healthcare Safety Network, being the primary cause of widespread pathologies such as significant diarrheal and extra-intestinal diseases or urinary tract infections. Furthermore, E. coli can be found as a bacterial food contamination and causes avian coli-bacillosis, one of the major bacterial diseases in the poultry industry and the most common avian disease communicable to humans. Currently, bacterium presence detection involve long time culture processes only to obtain a valid sample which could be properly detected. DEP concentration is a strong selective manipulation method which allows reducing sample preparation time. Moreover, by taking profit of IS, E. coli could be rapidly detected in the same equipment. For that reason, it is thought the proposed devices will be a useful tool for some current microbiology laboratories.
Hence the mainly aims of the present thesis are: (I) to prove the feasibility of custom DEP generator for controlling bacteria and find the best signal to accomplish this, (II) to look for the best microfluidic chip option for bacteria preconcentration purposes on bioanalytical applications, (III) to test the feasibility of a custom IS device and (IV) to use the previous studies to design a complete electronic equipment, taken profit of combination of both techniques to have an autonomous system (V) To demonstrate the proof of concept of the full device with the real case of E. coli concentration.El objetivo de esta tesis es el diseño de una instrumentación capaz de manipular y caracterizar células, a fin de realizar análisis más exhaustivos de elementos biológicos y acelerar procesos de detección de patógenos para aplicaciones de diagnóstico o de control de calidad de alimentos. El dispositivo se centra en dos tipos de técnicas eléctricas para la manipulación y detección de células: La dielectroforesis (DEP) y la medición de la bioimpedancia. La DEP permite manipular material biológico por medio de campos eléctricos, aprovechando las propiedades eléctricas de la célula y el medio en que se encuentra. La manipulación es por tanto ajustable, mediante el control de estas propiedades, así como a través de la geometría de los electrodos usados, la frecuencia y el módulo de la tensión aplicada. Por otro lado, la IS permite caracterizar material biológico mediante su comportamiento eléctrico en frecuencia. La medida se realiza a través de la aplicación de una corriente alterna controlada y la monitorización del efecto sobre el tejido mediante potencial eléctrico. Los dispositivos de IS son fácilmente integrables con técnicas dielectroforéticas de manipulación, fusionando manipulación con detección. En esta tesis, la combinación de estas técnicas permite la concentración de pequeños patógenos en grandes volúmenes de muestras y su posterior detección. Para ello, se crean diversos módulos de instrumentación electrónica. Algunos, están dedicados a generar señales alternas desfasadas a frecuencias óptimas para la manipulación de patógenos (módulo DEP). Otros, combinan módulos de generación, lectura y tratamiento digital, para la monitorización del comportamiento eléctrico de células (IS). Los módulos diseñados son validados en un entorno real controlado para concentrar y detectar la bacteria Escherichia Coli en grandes volúmenes de agua. Como resultado, se obtiene una electrónica modular válida, autónoma, portátil y de bajo coste, capaz de disminuir tiempos de preparación y detección de muestras en laboratorio.
8
Burn, C. C. "Effects of husbandry manipulations and the laboratory environment on rat health and welfare". Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.433382.
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Ng, Koon-kiu, e 吳官橋. "Using zebrafish as a model organism for the study of embryonic hematopoiesis based on chemical screening and genetic manipulation". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B5071322X.
Abstract (sommario):
Zebrafish has emerged as an important model for the study of embryonic hematopoiesis. It is a well-characterized model with numerous advantages. Large amount of embryos can be produced by a single pair of zebrafish and the optically transparent embryos allow direct visualization and manipulation of embryonic processes. Large-scale chemical screening using zebrafish embryos can be developed for robust screening of chemical libraries.
The zebrafish hematopoiesis resembles that of mammals and occurs in two successive waves, primitive and definitive hematopoiesis. High-throughput read-outs are available to study the effects of different chemicals and genetic modifications on hematopoiesis.
In first part of this study, an initial screening using O-dianisidine staining and whole-mount in-situ hybridization as read-out for chemicals that might perturb the regulation of hematopoiesis was conducted. Positive hit was further evaluated by flow cytometry of dissociated transgenic Tg(gata1:GFP) zebrafish embryos. A total of 50 compounds were screened from the "Mechanistic set" chemical libraries obtained from Developmental Therapeutics Program of the National Cancer Institute. One compound, "NSC 643834" was shown to reduce O-dianisidine staining at different concentrations tested.
The second part of this study was performed to investigate the role of inca2 in zebrafish hematopoiesis. inca2 was found to be upregulated in chordin morphant zebrafish in which primitive hematopoiesis was expanded. The spatial expression of inca2 was examined by whole mount in-situ hybridization of embryos at different developmental stages. Furthermore the function of inca2 was investigated by gene knockdown using inca2 anti-sense morpholino. Primitive hematopoiesis was perturbed, suggesting that inca2 might play an important role in the regulation of this process.
In conclusion, the present study demonstrated the distinct advantages and feasibility of using zebrafish as a platform of high throughput chemical screening and genetic manipulation. The result provided important ground to investigate the regulatory mechanisms of embryonic hematopoiesis.published_or_final_version
Medicine
Master
Master of Research in Medicine
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Ceballo, Charpentier Sebastian Arturo. "Causal manipulations of auditory perception and learning strategies in the mouse auditory cortex". Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS058.
Abstract (sommario):
À travers des nos sens, le cerveau reçoit une énorme quantité des informations. Cette information doit être filtrée afin d'extraire les caractéristiques les plus saillantes pour guider notre comportement. La façon dont le cerveau génère différents percepts et conduit les comportements, reste comme deux des majeures questions de la neuroscience moderne. Dans ce travail, en utilisant une tâche de discrimination Go / noGo combinée à l’optogénétique pour inactiver le cortex auditif durant le comportement la souris, nous avons établi que le cortex auditif n’est pas utilisé pour les discriminations de fréquence simples, mais qu’il était nécessaire pour résoudre une tâche plus difficile. En combinant différentes techniques de cartographie et l’optogénétique sculptée pour activer des champs tonotopiques définis avec précision dans le cortex auditif, nous avons pu élucider la stratégie utilisée par les souris pour résoudre cette tâche difficile, révélant ainsi un mécanisme de discrimination de fréquence retardé. En parallèle, des observations sur la vitesse d'apprentissage et l'activité des différents sons dans le cortex auditif nous ont amenés à étudier leurs interactions et à tester de manière causale le rôle du recrutement cortical dans l'apprentissage associatif, le révélant comme un possible corrélat neurophysiologique de la saillanceThrough our senses, the brain receives an enormous amount of information. This information needs to be filtered in order to extract the most salient features to guide our behavior. How the brain actually generates different percepts and drives behavior, remain the two major questions in modern neuroscience. To answer these questions, novel neural engineering approaches are now employed to map, model and finally generate, artificial sensory perception with its learned or innate associated behavioral outcome. In this work, using a Go/noGo discrimination task combined with optogenetics to silence auditory cortex during ongoing behavior in mice, we have established the dispensable role of auditory cortex for simple frequency discriminations, but also its necessary role to solve a more challenging task. By the combination of different mapping techniques and light-sculpted optogenetics to activate precisely defined tonotopic fields in auditory cortex, we could elucidate the strategy that mice use to solve this hard task, revealing a delayed frequency discrimination mechanism. In parallel, observations about learning speed and sound-triggered activity in auditory cortex, led us to study their interactions and causally test the role of cortical recruitment in associative learning, revealing it as a possible neurophysiological correlate of saliency
Libri sul tema "Manipulation de laboratoire":
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D, Marzin, a cura di. Manipulation de produits mutagènes et cancérogènes. Paris: Les Editions INSERM, 1998.
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Bernier, Stéphane. 100 fiches pratiques: Sécurité des produits chimiques au laboratoire. 2a ed. Paris: Dunod, 2008.
3
Hackett, Perry B. An introduction to recombinant DNA techniques: Basic experiments in gene manipulation. 2a ed. Menlo Park, Calif: Benjamin/Cummings, 1988.
4
A, Hopwood D., e John Innes Foundation, a cura di. Genetic manipulation of streptomyces: A laboratory manual. Norwich: John Innes Foundation, 1985.
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Pomilio, Alicia B. Métodos experimentales de laboratorio en química orgánica. Washington, D.C: Secretaría General de la Organización de los Estados Americanos, Programa Regional de Desarrollo Científico y Tecnológico, 1988.
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Carson, Susan. Manipulation and expression of recombinant DNA: A laboratory manual. 2a ed. Burlington, MA: Elsevier Academic, 2006.
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Robertson, Dominique. Manipulation and expression of recombinant DNA: A laboratory manual. San Diego: Academic Press, 1997.
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Hogan, Brigid. Manipulating the mouse embryo: A laboratory manual. Cold Spring Harbor, N.Y: Cold Spring Harbor Laboratory, 1986.
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Hogan, Brigid. Manipulating the mouse embryo: A laboratory manual. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory, 1986.
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Brigid, Hogan, a cura di. Manipulating the mouse embryo: A laboratory manual. 2a ed. Plainview, N.Y: Cold Spring Harbor Laboratory Press, 1994.
Capitoli di libri sul tema "Manipulation de laboratoire":
1
Li, Xiu-Qing. "Laboratory Methods for Investigating Nuclear and Cytoplasmic Genomes and Transcriptome". In Somatic Genome Manipulation, 323–52. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4939-2389-2_14.
2
Milton, John, e Toru Ohira. "Characterizing and Manipulating Oscillations". In Mathematics as a Laboratory Tool, 339–62. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-69579-8_12.
3
Gardner, R. L. "Embryo Transfer and Manipulation". In New Developments in Biosciences: Their Implications for Laboratory Animal Science, 147–62. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-3281-4_27.
4
Chrysostomou, Eleni, Febrimarsa, Timothy DuBuc e Uri Frank. "Gene Manipulation in Hydractinia". In Methods in Molecular Biology, 419–36. New York, NY: Springer US, 2022. http://dx.doi.org/10.1007/978-1-0716-2172-1_22.
Abstract (sommario):
AbstractThe ability to regenerate lost body parts is irregularly distributed among animals, with substantial differences in regenerative potential between and within metazoan phyla. It is widely believed that regenerative animal clades inherited some aspects of their capacity to regenerate from their common ancestors but have also evolved new mechanisms that are not shared with other regenerative animals. Therefore, to gain a broad understanding of animal regenerative mechanisms and evolution, a broad sampling approach is necessary. Unfortunately, only few regenerative animals have been established as laboratory models with protocols for functional gene studies. Here, we describe the methods to establish transgenic individuals of the marine cnidarian Hydractinia. We also provide methods for transient gene expression manipulation without modifying the genome of the animals.
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Highfield, P. E. "The use of gene manipulation for the production of antigens". In New Technologies in Clinical Laboratory Science, 45–48. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4928-7_6.
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Teodoro, Vitor Duarte. "Direct Manipulation of Physical Concepts in a Computerized Exploratory Laboratory". In Computer-Based Learning Environments and Problem Solving, 445–64. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-77228-3_21.
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Neuwelt, Edward A. "Blood-Brain Barrier Manipulation: Current Status of Laboratory and Clinical Studies". In New Concepts of a Blood—Brain Barrier, 277–85. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4899-1054-7_27.
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D’Amelio, Marcello, e Francesco Cecconi. "Apoptosome Pharmacological Manipulation: From Current Developments in the Laboratory to Clinical Implications". In Apoptosome, 271–81. Dordrecht: Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-3415-1_14.
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St-Onge, David, Corentin Boucher e Bruno Belzile. "Deployment of Advanced Robotic Solutions: The ROS Mobile Manipulator Laboratories". In Foundations of Robotics, 515–36. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-1983-1_18.
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Taib, Mariam, Hazlina Ahamad Zakeri, Azila Adnan, Muhamad Fairus Noor Hassim e Aziz Ahmad. "Assessing Core Manipulative Skills in a Biochemistry Laboratory Practical Test". In Alternative Assessments in Malaysian Higher Education, 151–59. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-7228-6_15.
Atti di convegni sul tema "Manipulation de laboratoire":
1
Kardos, Slavomir, Alena Pietrikova, Juraj Durisin e Martin Kusko. "Encased manipulation chamber for technologic laboratory". In 2010 33rd International Spring Seminar on Electronics Technology (ISSE). IEEE, 2010. http://dx.doi.org/10.1109/isse.2010.5547338.
2
Fairchild, Mark D., e Mike Stokes. "Electronic color image reproduction". In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.tuv3.
Abstract (sommario):
Successful electronic color image reproduction requires knowledge and control of many parameters. These include device characterization, image storage, image manipulation, and image perception. We describe the research environment that has been developed at the Munsell Color Science Laboratory to address these parameters. The use of this environment for the psychophysical determination of device-independent perceptibility and acceptability tolerances to global color changes in pictorial images is presented. In addition, the groundwork for future research in cross-media color reproduction is described. The research environment consists of the hardware necessary for the colorimetric characterization of all type of color image input, output, and display devices, software for the manipulation of color images in a wide range of color spaces, hardware for image input, processing, display, and output, and facilities for psychophysical research. Perceptibility and acceptability tolerances were measured for pictorial images by manipulating them using transfer functions along the colorimetrically specified lightness, chroma, and hue dimensions (CIELAB L*C*h°). It was found that simple measures of color difference are not adequate for describing the perception of color shifts in images.
3
De Luca, Anna Chiara. "SERS-bases biosensors for biomedical applications". In Optical Manipulation and Its Applications. Washington, D.C.: Optica Publishing Group, 2023. http://dx.doi.org/10.1364/oma.2023.atu2d.4.
Abstract (sommario):
Surface-enhanced Raman scattering (SERS) has received increasing research interest due to its excellent resolution, high sensitivity and rapid detection of low concentration analytes, particularly in biomedicine. Herein, it is provided an overview of recent developments and applications of SERS-based nanosensors and nanoreporters developed in our laboratory for use in biochemical monitoring, medical diagnostics, and therapy. The design and fabrication of different types of plasmonic-active nanostructures and devices, including fiber-optrode SERS sensors and hybrid nanovectors for drug delivery and local sensing, will be discussed. The applications of the SERS nanosensors for protein detection as well as local quantification and controlled release of drugs in living cancer cells will be presented.
4
Correa, Julio C., Juan A. Rami´rez, Elkin A. Taborda, Jorge A. Cock, Manuel A. Go´mez e Gustavo A. Escobar. "Implementation of a Laboratory for the Study of Robot Manipulators". In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39136.
Abstract (sommario):
This paper presents the process followed in the Department of Mechanical Engineering at Universidad Pontificia Bolivariana in Medellin, Colombia to implement a laboratory for the study of robot manipulators. The lab includes the following components: an industrial serial manipulator and the software developed for its integration to a graduate course, a parallel manipulator, a Cartesian robot, an inverted pendulum and a small serial manipulator. Except for the industrial robot, all the other devices were manufactured at the University. For all prototypes, specific software to control them has been developed.
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Zhao, Minghui, e Dongxin Zhao. "Establishment of Virtual Laboratory for Mining Special Manipulator". In 2019 2nd International Conference on Artificial Intelligence and Big Data (ICAIBD). IEEE, 2019. http://dx.doi.org/10.1109/icaibd.2019.8837032.
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Baczynski, Janusz, e Michal Baczynski. "Simple cable-driven manipulator system as laboratory assistant". In 2010 IEEE/ASME International Conference on Mechatronic and Embedded Systems and Applications (MESA). IEEE, 2010. http://dx.doi.org/10.1109/mesa.2010.5552063.
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Musyoka, James, John Lunalo, Cathy Garlick, Steven Ndung’u, David Stern, Danny Parsons e Roger Stern. "Embedding data manipulation in statistics education". In Teaching Statistics in a Data Rich World. International Association for Statistical Education, 2017. http://dx.doi.org/10.52041/srap.17503.
Abstract (sommario):
University courses in statistics in many African countries are dominated by data analysis. This is just one component of the subject and students therefore lack knowledge on many important practical laboratory work components. Here we consider how data collection and data entry can be included in training courses. The next important stage of preparing the data, so it is ready for analysis is also considered. These stages, before data analysis, may use a combination of a spreadsheet, a statistics package and special software. Examples of each are considered.
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Langerman, Michael A., Gregory A. Buck, Umesh A. Korde e Vojislav D. Kalanovic. "Thermal Control of Laser Powder Deposition: Heat Transfer Considerations". In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60386.
Abstract (sommario):
Laser based solid free-form fabrication is an emerging metallurgical forming process aimed at rapid production of high quality, near net shape products directly from starting powders. Laser powder deposition shares, with other free-form technologies, the common characteristic that part fabrication occurs directly from a 3-D computer aided design (CAD) model. The microstructure evolution and resulting material properties of the component part (strength, ductility, etc.) fabricated using laser deposition are dependent upon process operating parameters such as melt pool size, laser power, head (manipulator) speed, and powder flow rate. Presently, set points for these parameters are often determined through manual manipulation of the system control and trial and error. This paper discusses the development of a path-planning, feed-forward, process-driven control system algorithm that generates a component part thermal history within given constraints, thereby assuring optimal part quality and minimizing final residual stresses. A thermal model of the deposition process drives the control algorithm. The development of the thermal model is the subject of this paper. The model accounts for temperature-dependent properties and phase change processes. Model validation studies are presented including comparisons with known analytic solutions as well as comparisons with data from experiments conducted in the laser laboratory at SDSM&T.
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Bonotto, D. M., B. W. Tessari, G. Girello e V. R. Roveratti. "The licensing of a laboratory for manipulating radionuclides in Brazil". In ENVIRONMENTAL HEALTH RISK 2013. Southampton, UK: WIT Press, 2013. http://dx.doi.org/10.2495/ehr130031.
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McCourt, Richard, e Clarence W. de Silva. "Application of Predictive Control for Autonomous Satellite Capture Using a Deployable Manipulator System". In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43718.
Abstract (sommario):
Two prototypes of a robot known as the Multi-module Deployable Manipulator System (MDMS) have been developed in our laboratory. This manipulator is intended for carrying for research in space platform-based robotics. In the present paper, this manipulator is used in laboratory-simulated capture of an orbiting satellite. A model-based predictive controller is developed and implemented in the MDMS. Using the controlled manipulator, laboratory experiments are carried out to study autonomous capture of a free floating and spinning target. The objective is to evaluate the performance of the predictive controller for the capturing task. A planar prototype MDMS is used as the chaser robot in experiments, and the target statellite is simulated within the controller. The model of the target statelite assumes that it is free of any external torques and involves rotations within the plane of operation of the MDMS prototype. The predictions for the chaser robot are based on a model of the MDMS, linearized about the starting configuration of the task. An unconstrained predictive controller is used in the present experiments. The resluts from tracking various moving target are presented, with and without predictions of the target movement. The performance is shown to be quite satisfactory.
Rapporti di organizzazioni sul tema "Manipulation de laboratoire":
1
Kress, R. L., J. F. Jansen, L. J. Love e A. M. H. Basher. Hydraulic manipulator design, analysis, and control at Oak Ridge National Laboratory. Office of Scientific and Technical Information (OSTI), settembre 1996. http://dx.doi.org/10.2172/665942.
2
Matthew, Gray. Data from "Winter is Coming – Temperature Affects Immune Defenses and Susceptibility to Batrachochytrium salamandrivorans". University of Tennessee, Knoxville Libraries, gennaio 2021. http://dx.doi.org/10.7290/t7sallfxxe.
Abstract (sommario):
Environmental temperature is a key factor driving various biological processes, including immune defenses and host-pathogen interactions. Here, we evaluated the effects of environmental temperature on the pathogenicity of the emerging fungus, Batrachochytrium salamandrivorans (Bsal), using controlled laboratory experiments, and measured components of host immune defense to identify regulating mechanisms. We found that adult and juvenile Notophthalmus viridescens died faster due to Bsal chytridiomycosis at 14 ºC than at 6 and 22 ºC. Pathogen replication rates, total available proteins on the skin, and microbiome composition likely drove these relationships. Temperature-dependent skin microbiome composition in our laboratory experiments matched seasonal trends in wild N. viridescens, adding validity to these results. We also found that hydrophobic peptide production after two months post-exposure to Bsal was reduced in infected animals compared to controls, perhaps due to peptide release earlier in infection or impaired granular gland function in diseased animals. Using our temperature-dependent infection results, we performed a geographic analysis that suggested that N. viridescens populations in the northeastern United States and southeastern Canada are at greatest risk for Bsal invasion. Our results indicate that environmental temperature will play a key role in the epidemiology of Bsal and provide evidence that temperature manipulations may be a viable Bsal management strategy.
3
March-Leuba, S., J. F. Jansen, R. L. Kress, S. M. Babcock e R. V. Dubey. Development of the Symbolic Manipulator Laboratory modeling package for the kinematic design and optimization of the Future Armor Rearm System robot. Office of Scientific and Technical Information (OSTI), agosto 1992. http://dx.doi.org/10.2172/6956182.
4
March-Leuba, S., J. F. Jansen, R. L. Kress, S. M. Babcock e R. V. Dubey. Development of the Symbolic Manipulator Laboratory modeling package for the kinematic design and optimization of the Future Armor Rearm System robot. Ammunition Logistics Program. Office of Scientific and Technical Information (OSTI), agosto 1992. http://dx.doi.org/10.2172/10191974.
5
Droby, Samir, Michael Wisniewski, Martin Goldway, Wojciech Janisiewicz e Charles Wilson. Enhancement of Postharvest Biocontrol Activity of the Yeast Candida oleophila by Overexpression of Lytic Enzymes. United States Department of Agriculture, novembre 2003. http://dx.doi.org/10.32747/2003.7586481.bard.
Abstract (sommario):
Enhancing the activity of biocontrol agents could be the most important factor in their success in controlling fruit disease and their ultimate acceptance in commercial disease management. Direct manipulation of a biocontrol agent resulting in enhancement of diseases control could be achieved by using recent advances in molecular biology techniques. The objectives of this project were to isolate genes from yeast species that were used as postharvest biocontrol agents against postharvest diseases and to determine their role in biocontrol efficacy. The emphasis was to be placed on the yeast, Candida oleophila, which was jointly discovered and developed in our laboratories, and commercialized as the product, Aspire. The general plan was to develop a transformation system for C . oleophila and either knockout or overexpress particular genes of interest. Additionally, biochemical characterization of the lytic peptides was conducted in the wild-type and transgenic isolates. In addition to developing a better understanding of the mode of action of the yeast biocontrol agents, it was also our intent to demonstrate the feasibility of enhancing biocontrol activity via genetic enhancement of yeast with genes known to code for proteins with antimicrobial activity. Major achievements are: 1) Characterization of extracellular lytic enzymes produced by the yeast biocontrol agent Candida oleophila; 2) Development of a transformation system for Candida oleophila; 3) Cloning and analysis of C.oleophila glucanase gene; 4) Overexpression of and knockout of C. oleophila glucanase gene and evaluating its role in the biocontrol activity of C. oleophila; 5) Characterization of defensin gene and its expression in the yeast Pichiapastoris; 6) Cloning and Analysis of Chitinase and Adhesin Genes; 7) Characterization of the rnase secreted by C . oleophila and its inhibitory activity against P. digitatum. This project has resulted in information that enhanced our understanding of the mode of action of the yeast C . oleophila. This was important step towards enhancing the biocontrol activity of the yeast. Fungal cell wall enzymes produced by the yeast antagonist were characterized. Different substrates were identified to enhance there production in vitro. Exo-b-1, 3 glucanase, chitinase and protease production was stimulated by the presence of cell-wall fragments of Penicillium digitatum in the growing medium, in addition to glucose. A transformation system developed was used to study the role of lytic enzymes in the biocontrol activity of the yeast antagonist and was essential for genetic manipulation of C . oleqphila. After cloning and characterization of the exo-glucanase gene from the yeast, the transformation system was efficiently used to study the role of the enzyme in the biocontrol activity by over-expressing or knocking out the activity of the enzyme. At the last phase of the research (still ongoing) the transformation system is being used to study the role of chitinase gene in the mode of action. Knockout and over expression experiments are underway.
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Morrison, Mark, e Joshuah Miron. Molecular-Based Analysis of Cellulose Binding Proteins Involved with Adherence to Cellulose by Ruminococcus albus. United States Department of Agriculture, novembre 2000. http://dx.doi.org/10.32747/2000.7695844.bard.
Abstract (sommario):
At the beginning of this project, it was clear that R. albus adhered tightly to cellulose and its efficient degradation of this polysaccharide was dependent on micromolar concentrations of phenylacetic acid (PAA) and phenylpropionic acid (PPA). The objectives for our research were: i) to identify how many different kinds of cellulose binding proteins are produced by Ruminococcus albus; ii) to isolate and clone the genes encoding some of these proteins from the same bacterium; iii) to determine where these various proteins were located and; iv) quantify the relative importance of these proteins in affecting the rate and extent to which the bacterium becomes attached to cellulose. BARD support has facilitated a number of breakthroughs relevant to our fundamental understanding of the adhesion process. First, R. albus possesses multiple mechanisms for adhesion to cellulose. The P.I.'s laboratory has discovered a novel cellulose-binding protein (CbpC) that belongs to the Pil-protein family, and in particular, the type 4 fimbrial proteins. We have also obtained genetic and biochemical evidence demonstrating that, in addition to CbpC-mediated adhesion, R. albus also produces a cellulosome-like complex for adhesion. These breakthroughs resulted from the isolation (in Israel and the US) of spontaneously arising mutants of R. albus strains SY3 and 8, which were completely or partially defective in adhesion to cellulose, respectively. While the SY3 mutant strain was incapable of growth with cellulose as the sole carbon source, the strain 8 mutants showed varying abilities to degrade and grow with cellulose. Biochemical and gene cloning experiments have been used in Israel and the US, respectively, to identify what are believed to be key components of a cellulosome. This combination of cellulose adhesion mechanisms has not been identified previously in any bacterium. Second, differential display, reverse transcription polymerase chain reaction (DD RT-PCR) has been developed for use with R. albus. A major limitation to cellulose research has been the intractability of cellulolytic bacteria to genetic manipulation by techniques such as transposon mutagenesis and gene displacement. The P.I.'s successfully developed DD RT- PCR, which expanded the scope of our research beyond the original objectives of the project, and a subset of the transcripts conditionally expressed in response to PAA and PPA have been identified and characterized. Third, proteins immunochemically related to the CbpC protein of R. albus 8 are present in other R. albus strains and F. intestinalis, Western immunoblots have been used to examine additional strains of R. albus, as well as other cellulolytic bacteria of ruminant origin, for production of proteins immunochemically related to the CbpC protein. The results of these experiments showed that R. albus strains SY3, 7 and B199 all possess a protein of ~25 kDa which cross-reacts with polyclonal anti-CbpC antiserum. Several strains of Butyrivibrio fibrisolvens, Ruminococcus flavefaciens strains C- 94 and FD-1, and Fibrobacter succinogenes S85 produced no proteins that cross-react with the same antiserum. Surprisingly though, F. intestinalis strain DR7 does possess a protein(s) of relatively large molecular mass (~200 kDa) that was strongly cross-reactive with the anti- CbpC antiserum. Scientifically, our studies have helped expand the scope of our fundamental understanding of adhesion mechanisms in cellulose-degrading bacteria, and validated the use of RNA-based techniques to examine physiological responses in bacteria that are nor amenable to genetic manipulations. Because efficient fiber hydrolysis by many anaerobic bacteria requires both tight adhesion to substrate and a stable cellulosome, we believe our findings are also the first step in providing the resources needed to achieve our long-term goal of increasing fiber digestibility in animals.
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Hansen, Peter J., e Amir Arav. Embryo transfer as a tool for improving fertility of heat-stressed dairy cattle. United States Department of Agriculture, settembre 2007. http://dx.doi.org/10.32747/2007.7587730.bard.
Abstract (sommario):
The overall objective of the current proposal is to develop procedures to improve the pregnancy rate achieved following transfer of fresh or cryopreserved embryos produced in the laboratory into heat-stress recipients. The overall hypothesis is that pregnancy rate in heat-stressed lactating cows can be improved by use of embryo transfer and that additional gains in pregnancy rate can be achieved through development of procedures to cryopreserve embryos, select embryos most likely to establish and maintain pregnancy after transfer, and to enhance embryo competence for post-transfer survival through manipulation of culture conditions. The original specific objectives were to 1) optimize procedures for cryopreservation (Israel/US), 2) develop procedures for identifying embryos with the greatest potential for development and survival using the remote monitoring system called EmbryoGuard (Israel), 3) perform field trials to test the efficacy of cryopreservation and the EmbryoGuard selection system for improving pregnancy rates in heat-stressed, lactating cows (US/Israel), 4) test whether selection of fresh or frozen-thawed blastocysts based on measurement of group II caspase activity is an effective means of increasing survival after cryopreservation and post-transfer pregnancy rate (US), and 5) identify genes in blastocysts induced by insulin-like growth factor-1 (IGF-1) (US). In addition to these objectives, additional work was carried out to determine additional cellular determinants of embryonic resistance to heat shock. There were several major achievements. Results of one experiment indicated that survival of embryos to freezing could be improved by treating embryos with cytochalasin B to disrupt the cytoskeleton. An additional improvement in the efficacy of embryo transfer for achieving pregnancy in heat-stressed cows follows from the finding that IGF-1 can improve post-transfer survival of in vitro produced embryos in the summer but not winter. Expression of several genes in the blastocyst was regulated by IGF-1 including IGF binding protein-3, desmocollin II, Na/K ATPase, Bax, heat shock protein 70 and IGF-1 receptor. These genes are likely candidates 1) for developing assays for selection of embryos for transfer and 2) as marker genes for improving culture conditions for embryo production. The fact that IGF-1 improved survival of embryos in heat-stressed recipients only is consistent with the hypothesis that IGF-1 confers cellular thermotolerance to bovine embryos. Other experiments confirmed this action of IGF-1. One action of IGF-1, the ability to block heat-shock induced apoptosis, was shown to be mediated through activation of the phosphatidylinositol 3-kinase pathway. Other cellular determinants of resistance of embryos to elevated temperature were identified including redox status of the embryo and the ceramide signaling pathway. Developmental changes in embryonic apoptosis responses in response to heat shock were described and found to include alterations in the capacity of the embryo to undergo caspase-9 and caspase-3 activation as well as events downstream from caspase-3 activation. With the exception of IGF-1, other possible treatments to improve pregnancy rate to embryo transfer were not effective including selection of embryos for caspase activity, treatment of recipients with GnRH.and bilateral transfer of twin embryos. In conclusion, accomplishments achieved during the grant period have resulted in methods for improving post-transfer survival of in vitro produced embryos transferred into heat-stressed cows and have lead to additional avenues for research to increase embryo resistance to elevated temperature and improve survival to cryopreservation. In addition, embryo transfer of vitrified IVF embryos increased significantly the pregnancy rate in repeated breeder cows.
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Shmulevich, Itzhak, Shrini Upadhyaya, Dror Rubinstein, Zvika Asaf e Jeffrey P. Mitchell. Developing Simulation Tool for the Prediction of Cohesive Behavior Agricultural Materials Using Discrete Element Modeling. United States Department of Agriculture, ottobre 2011. http://dx.doi.org/10.32747/2011.7697108.bard.
Abstract (sommario):
The underlying similarity between soils, grains, fertilizers, concentrated animal feed, pellets, and mixtures is that they are all granular materials used in agriculture. Modeling such materials is a complex process due to the spatial variability of such media, the origin of the material (natural or biological), the nonlinearity of these materials, the contact phenomenon and flow that occur at the interface zone and between these granular materials, as well as the dynamic effect of the interaction process. The lack of a tool for studying such materials has limited the understanding of the phenomena relevant to them, which in turn has led to energy loss and poor quality products. The objective of this study was to develop a reliable prediction simulation tool for cohesive agricultural particle materials using Discrete Element Modeling (DEM). The specific objectives of this study were (1) to develop and verify a 3D cohesionless agricultural soil-tillage tool interaction model that enables the prediction of displacement and flow in the soil media, as well as forces acting on various tillage tools, using the discrete element method; (2) to develop a micro model for the DEM formulation by creating a cohesive contact model based on liquid bridge forces for various agriculture materials; (3) to extend the model to include both plastic and cohesive behavior of various materials, such as grain and soil structures (e.g., compaction level), textures (e.g., clay, loam, several grains), and moisture contents; (4) to develop a method to obtain the parameters for the cohesion contact model to represent specific materials. A DEM model was developed that can represent both plastic and cohesive behavior of soil. Soil cohesive behavior was achieved by considering tensile force between elements. The developed DEM model well represented the effect of wedge shape on soil behavior and reaction force. Laboratory test results showed that wedge penetration resistance in highly compacted soil was two times greater than that in low compacted soil, whereas DEM simulation with parameters obtained from the test of low compacted soil could not simply be extended to that of high compacted soil. The modified model took into account soil failure strength that could be changed with soil compaction. A three dimensional representation composed of normal displacement, shear failure strength and tensile failure strength was proposed to design mechanical properties between elements. The model based on the liquid bridge theory. An inter particle tension force measurement tool was developed and calibrated A comprehensive study of the parameters of the contact model for the DEM taking into account the cohesive/water-bridge was performed on various agricultural grains using this measurement tool. The modified DEM model was compared and validated against the test results. With the newly developed model and procedure for determination of DEM parameters, we could reproduce the high compacted soil behavior and reaction forces both qualitatively and quantitatively for the soil conditions and wedge shapes used in this study. Moreover, the effect of wedge shape on soil behavior and reaction force was well represented with the same parameters. During the research we made use of the commercial PFC3D to analyze soil tillage implements. An investigation was made of three different head drillers. A comparison of three commonly used soil tillage systems was completed, such as moldboard plow, disc plow and chisel plow. It can be concluded that the soil condition after plowing by the specific implement can be predicted by the DEM model. The chisel plow is the most economic tool for increasing soil porosity. The moldboard is the best tool for soil manipulation. It can be concluded that the discrete element simulation can be used as a reliable engineering tool for soil-implement interaction quantitatively and qualitatively.
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Dickman, Martin B., e Oded Yarden. Genetic and chemical intervention in ROS signaling pathways affecting development and pathogenicity of Sclerotinia sclerotiorum. United States Department of Agriculture, luglio 2015. http://dx.doi.org/10.32747/2015.7699866.bard.
Abstract (sommario):
Abstract: The long-term goals of our research are to understand the regulation of sclerotial development and pathogenicity in S. sclerotior11111. The focus in this project was on the elucidation of the signaling events and environmental cues involved in the regulation of these processes, utilizing and continuously developing tools our research groups have established and/or adapted for analysis of S. sclerotiorum, Our stated objectives: To take advantage of the recent conceptual (ROS/PPs signaling) and technical (amenability of S. sclerotiorumto manipulations coupled with chemical genomics and next generation sequencing) developments to address and extend our fundamental and potentially applicable knowledge of the following questions concerning the involvement of REDOX signaling and protein dephosphorylation in the regulation of hyphal/sclerotial development and pathogenicity of S. sclerotiorum: (i) How do defects in genes involved in ROS signaling affect S. sclerotiorumdevelopment and pathogenicity? (ii) In what manner do phosphotyrosinephosphatases affect S. sclerotiorumdevelopment and pathogenicity and how are they linked with ROS and other signaling pathways? And (iii) What is the nature of activity of newly identified compounds that affect S. sclerotiori,111 growth? What are the fungal targets and do they interfere with ROS signaling? We have met a significant portion of the specific goals set in our research project. Much of our work has been published. Briefly. we can summarize that: (a) Silencing of SsNox1(NADPHoxidase) expression indicated a central role for this enzyme in both virulence and pathogenic development, while inactivation of the SsNox2 gene resulted in limited sclerotial development, but the organism remained fully pathogenic. (b) A catalase gene (Scatl), whose expression was highly induced during host infection is involved in hyphal growth, branching, sclerotia formation and infection. (c) Protein tyrosine phosphatase l (ptpl) is required for sclerotial development and is involved in fungal infection. (d) Deletion of a superoxidedismutase gene (Sssodl) significantly reduced in virulence on both tomato and tobacco plants yet pathogenicity was mostly restored following supplementation with oxalate. (e) We have participated in comparative genome sequence analysis of S. sclerotiorumand B. cinerea. (f) S. sclerotiorumexhibits a potential switch between biotrophic and necrotrophic lifestyles (g) During plant microbe interactions cell death can occur in both resistant and susceptible events. Non pathogenic fungal mutants S. sclerotior111n also cause a cell death but with opposing results. We investigated PCD in more detail and showed that, although PCD occurs in both circumstances they exhibit distinctly different features. The mutants trigger a restricted cell death phenotype in the host that unexpectedly exhibits markers associated with the plant hypersensitive (resistant) response. Using electron and fluorescence microscopy, chemical effectors and reverse genetics, we have established that this restricted cell death is autophagic. Inhibition of autophagy rescued the non-pathogenic mutant phenotype. These findings indicate that autophagy is a defense response in this interaction Thus the control of cell death, dictated by the plant (autophagy) סr the fungus (apoptosis), is decisive to the outcome of certain plant microbe interactions. In addition to the time and efforts invested towards reaching the specific goals mentioned, both Pls have initiated utilizing (as stated as an objective in our proposal) state of the art RNA-seq tools in order to harness this technology for the study of S. sclerotiorum. The Pls have met twice (in Israel and in the US), in order to discuss .נחd coordinate the research efforts. This included a working visit at the US Pls laboratory for performing RNA-seq experiments and data analysis as well as working on a joint publication (now published). The work we have performed expands our understanding of the fundamental biology (developmental and pathogenic) of S. sclerotioז111וז. Furthermore, based on our results we have now reached the conclusion that this fungus is not a bona fide necrotroph, but can also display a biotrophic lifestyle at the early phases of infection. The data obtained can eventually serve .נ basis of rational intervention with the disease cycle of this pathogen.