9 research outputs found
Contribution à l'étude des interactions trigemino-gustatives périphériques et centrales (implication du nerf alvéolaire inférieur et du nerf lingual chez le rat)
No full textLors de la prise alimentaire, la détection et la transmission des signaux somesthésiques est assurée par le système trigéminal (V), notamment le nerf lingual (NL) destiné à la langue, et le nerf alvéolaire inférieur (NAI) responsable de l innervation des dents mandibulaires. La modalité gustative linguale est assurée par le nerf glossopharyngien (IX) et par une branche du nerf facial (VII), la corde du tympan (CT). Bien que distincts, les systèmes somesthésique et gustatif présentent de nombreuses interactions. Au cours de ce travail, nous nous sommes particulièrement intéressés aux interactions trigémino-gustatives périphériques et centrales chez le rat.Dans la première partie de ce travail, nous avons étudié l expression des transporteurs vésiculaires du glutamate (VGluts) dans les papilles gustatives linguales à l aide de techniques immuno-histochimiques. Nous avons tout d abord montré que seul VGlut 1, un marqueur du phénotype glutamatergique des neurones centraux, est présent dans les papilles gustatives linguales. Nous avons ensuite montré que certaines fibres de la CT et du NL expriment VGlut 1 dans les papilles fongiformes. Dans la deuxième partie de ce travail, nous nous sommes intéressés à la participation des neurones sensitifs primaires du NAI à la modulation du signal gustatif dans le noyau du tractus solitaire (NTS). A l aide d enregistrements électro-physiologiques unitaires, nous avons montré que les neurones du NAI modulent faiblement les réponses gustatives neuronales dans le NTS. Des techniques immuno-histochimiques ont ensuite permis de révéler la présence de projections des neurones du NAI sur des neurones gustatifs du NTS. Les données immuno-histologiques observées en périphérie indiquent la présence de fibres glutamatergiques de la CT et du NL dans les papilles fongiformes et suggèrent leur participation à la modulation périphérique du signal gustatif. Au niveau central, nos résultats précisent l implication des neurones du NAI, en particulier ceux qui innervent les dents mandibulaires, dans l intégration du signal gustatif.LILLE2-UFR Odontologie (593502202) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF
Etude du transfert d'oxygène dans un bioréacteur hybride immergé à membranes
No full textInternational audienceno abstrac
Impregnated Bits Design and Optimization: An Iterative Method for Improving Drilling Performances. Case Study: Hassi Messaoud Cambrian Reservoir in Algeria
No full textAbstract
Horizontal wells are drilled in Hassi Messaoud oilfield with 6" drains of +/−800m into the Cambrian reservoir using both PDM and Turbine. The multi layered reservoir is +/-3400m deep, mainly quartzite, sandstone and silt. Looking at the rock strength, the confined compressive strength can reach 60 kpsi. Therefore enhancing ROP and durability, when drilling the very hard and very abrasive Cambrian reservoir in Hassi Messaoud, remains one of the major drilling challenges.
This paper describes the iterative approach by which SONATRACH and NOV Downhole Tools Algeria are developing and improving impregnated bits for the very hard and very abrasive formations; for both applications: PDM and Turbine as well. The main objectives are to:
Enhance ROP. Increase durability. Maintain inclination and reasonable dogleg severity. Be able to drill out float equipments and shoe. Fit for both PDM and Turbine application Suit both OBD and UBD application
As all new bit types, a complete field study was carried out, including logs and rock strength analysis, offset wells comparison in order to bring into the light the first version of the design. Four versions of the impregnated bit were tested, so far.
The first version drilled 120m. A second version was tested, with an improvement related to the anti-coring cutters, replacing them by a new generation more wear resistant. The subsequent improvement consisted in increasing blade volume, enabling one of the best ROP achieved in Hassi Messaoud 5.27 m/h. To improve durability, blade volume was increased more. The bit achieved 365 m in one run, with an average ROP of 3.49 m/h.
In the last version developed and tested, an increase in the grit mix was made. The bit drilled an interval of 399 m with an average ROP of 3.89 m/h.
Furthermore, several design considerations have been taken into consideration in order to improve impregnated bits in relation to different types of lithology drilled. The newest design has the same blade volume and the same grit mix as the last bit design recently used in Hassi Messaoud field. However the blades are thicker and the hydraulics / water ways are optimized.</jats:p
A Holistic Approach to Drilling Parameters and Drill Bit Design Optimization Improves Rate of Penetration by 37%, Hassi Messaoud OMfield-Algeria
No full textAbstract
Drilling challenges in the Hassi Messaoud (HMD) oilfield have proven to be equal to the magnitude of its production. Historically, wells drilled in this field were vertical, moderate borehole diameters having a long 12 ¼"section. In order to increase production and to gain a better understanding of the reservoir, Sonatrach Drilling engineering moved to moderately deviated large diameter boreholes, delivering 1000 meters of drain in the reservoir.
Instead of the conventional 12 1/4’’ vertical section, 1800 meters was drilled in 16’’ diameter. This section consists of abrasive sands, inter-bedded evaporate/carbonate and sand/claystone formations prone to instability and collapse. In addition, there is a 30 meter band of extremely hard dolomite. Rock strengths vary widely from 5 Kpsi to 30Kpsi.
Since early 2000, Sonatrach and National Oilwell Varco (NOV) have been working as a team to rise to the challenges presented by the larger hole size. Most significantly drilling vibrations, slow penetration rates, increased trips to TD, severe bit and BHA damage and NPT due to stuck pipe while pulling out-of-hole.
This article describes first, the process by which significant performance improvement was achieved as a result of combining innovative bit design techniques and technologies, BHA optimization, optimization of parameters through BHA dynamics modelling, and formation Rock Strength Analysis.
Secondly, the article discusses optimized techniques introduced to enhance performance for the 16’’ section on rigs that have been recently equipped with VFD - AC top drives and properly deal with torque limitation issues.
This enabled Sonatrach to repeatedly set ROP drilling records as well as consistently making section TD in a single run. The net result was a 37% improvement in rate of penetration1.</jats:p
Antipeptide Polyclonal Antibodies that Recognize a Substance P-Binding Site in Mammalian Tissues: A Biochemical and Immunocytochemical Study
No full textAvaliação dos efeitos centrais da substância P free acid, dos inibidores de peptidases e das seqüências C- e N-Terminal da substância P no labirinto em cruz elevado em ratos
Get PDFDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-Graduação em Farmacologia
Evaluation of morphological changes in hippocampal neurons produced by facial nerve injury in rats
No full textilustraciones, gráficas, tablasDistintos modelos de lesión de nervios periféricos en ratas se han utilizado ampliamente para estudiar los cambios estructurales que ocurren, no solamente en las neuronas directamente afectadas, sino también en otras estructuras del sistema nervioso central relacionadas con el procesamiento sensoriomotor. El Grupo de Neurofisiología Comportamental, de la Universidad Nacional de Colombia, además de describir cambios a nivel morfológico, molecular y electrofisiológico generados en la corteza motora primaria de vibrisas por la lesión del nervio facial en ratas, ha descrito una disminución de la plasticidad a largo plazo en la sinapsis comisural CA3CA1 del hipocampo, asociada a este tipo de lesión. Sumado a ello, se ha encontrado un aumento en los niveles plasmáticos de corticosterona, una disminución en la consolidación de la memoria espacial y un aumento de la activación microglial en el hipocampo de animales con axotomía del nervio facial. En este trabajo se analizó la morfología neuronal de las células piramidales de las regiones CA3 y CA1 del hipocampo en ratas con lesión reversible o irreversible del nervio facial. Para este fin, se realizó una tinción del tejido cerebral con el método Golgi-cox en animales lesionados y sacrificados a distintos tiempos post-lesión, que se compararon con cerebros de animales control. Se evaluó la complejidad dendrítica mediante el análisis de Sholl y se calculó la densidad de espinas dendríticas de las regiones basal y apical. Se encontró que ambos tipos de lesión son capaces de producir disminuciones significativas en: 1) la complejidad del árbol dendrítico; 2) la longitud total de dendritas y 3) el número de espinas dendríticas. No obstante, se evidencia una tendencia a la recuperación de estas modificaciones en animales con lesión reversible del nervio facial (es decir, que son capaces de recuperar la función motora tras la lesión). Esta tendencia de reversión de las modificaciones está correlacionada con la recuperación funcional que los sujetos demuestran entre los días postoperatorios 14 y 35. Se concluye que la lesión del nervio facial, con la posibilidad de recuperación funcional o no, es capaz de producir cambios anatómicos en las neuronas piramidales de las regiones CA1 y CA3 del hipocampo. Dichos cambios denotan una reducción general de la complejidad del árbol dendrítico y de la densidad de espinas, que tiende a revertirse si hay recuperación de la función motora. (Texto tomado de la fuente)Several models of peripheral nerve injury in rats have been widely used to study the structural changes that occur in the injured neurons and other central nervous system structures related to sensorimotor processing. The Behavioral Neurophysiology Group (Universidad Nacional de Colombia), has described morphological, molecular and electrophysiological changes in the vibrissae primary motor cortex associated with facial nerve injury in rats. Moreover, recently it has been reported a decrease in long-term potentiation of hippocampal CA3-to-CA1 commissural synapse, related with this type of peripheral injury. In addition, it has been found increased corticosterone plasmatic levels, impediment in spatial memory consolidation, and hippocampal microglial activation in animals with facial nerve axotomy. In this work we analyzed the neuronal morphology of hippocampal CA3 and CA1 pyramidal cells in animals with reversible or irreversible facial nerve injury. For this purpose, brain tissue of injured animals sacrificed at different post-lesion times, were staining with Golgi-cox method and compared with control brains. It was found that both irreversible and reversible facial nerve injury produced significant decreases in 1) complexity of the dendritic tree; 2) dendrites total length; and 3) dendritic spine’s density. However, a trend toward recovery of these modifications is evident in animals with reversible facial nerve injury (i.e., that are able to recover motor function after injury). This trend is correlated with the recovery of motor function between 14- and 35-days post-injury. It is concluded that facial nerve injury produced significant changes in hippocampal CA1 and CA3 pyramidal neurons morphology. Such changes demonstrate a general reduction in the complexity of the dendritic tree and spine density, which tends to reverse if recovery of motor function is allowed.Fundación para la Promoción de la Investigación y la Tecnología. F.P.I.T - Banco de la RepúblicaMaestríaMagíster en Ciencias - BiologíaFisiología del control motor facia
