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Articoli di riviste sul tema "Defaut monophase"
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Grivas, Grigoris, Theano Lagousi e Georgia Mandilara. "Epidemiological Data, Serovar Distribution and Antimicrobial Resistance Patterns of Salmonella Species in Children, Greece 2011-2017: A Retrospective Study". Acta Medica Academica 49, n. 3 (12 marzo 2021): 255. http://dx.doi.org/10.5644/ama2006-124.315.
Testo completoAbstract (sommario):
<p class="Default"><strong><span>Objective. </span></strong><span>This study aimed to describe <em>Salmonella </em>epidemiology and antimicrobial resistance in Greek children over the period of 2011-2017. </span></p><p class="Default"><strong><span>Materials and Methods. </span></strong><span>A 7-year retrospective study (2011-2017) was performed, based on data recorded by the National Reference Centre for </span><em><span>Salmonella</span></em><span>, among children aged ≤14 years. Epidemiological data, serovar distribution and antimicrobial resistance patterns were recorded. </span></p><p class="Default"><strong><span>Results. </span></strong><span>Overall, 2347 <em>Salmonella </em>isolates were collected (27 typhoid-paratyphoid). Salmonellosis cases increased by almost 2-fold in 2017 compared to 2011. The highest rates were reported in August, with infants being the most vulnerable group (17.9%). The majority of isolates were identified in stool samples (91%). Boys slightly outnumbered girls (~1.05:1). <em>Salmonella Enteritidis </em>was the most prevalent serovar (28.5%), followed by <em>Salmonella Typhimurium </em>(12.2%) and <em>Salmonella monophasic Typhimurium </em>(10.4%). Non-typhoid isolates displayed low resistance rates to 3</span><span class="A13"><span>rd </span></span><span>generation cephalosporins (1%) and ciprofloxacin (0.3%), while the corresponding resistance of typhoid isolates was 10% and 5% respectively. An increasing trend of <em>Salmonella monophasic Typhimurium </em>was recorded, associated with high rates of multidrug resistance, reaching a percentage of 97.8% in 2017.</span></p><p class="Default"><strong><span>Conclusions. </span></strong><span>Salmonellosis epidemiology in Greek children is comparable to previously published European data. Antimicrobial resistance rates to 3</span><span class="A13"><span>rd</span></span><span>-generation cephalosporins and ciprofloxacin for non-typhoid and typhoid-paratyphoid remain low. Notably, there is an increasing prevalence of <em>Salmonella monophasic Typhimurium </em>isolates, associated with multiple antimicrobial resistance.</span></p>
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Johansson, Catarina, Björn Vennström e Peter Thorén. "Evidence that decreased heart rate in thyroid hormone receptor-α1-deficient mice is an intrinsic defect". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 275, n. 2 (1 agosto 1998): R640—R646. http://dx.doi.org/10.1152/ajpregu.1998.275.2.r640.
Testo completoAbstract (sommario):
Using a telemetry system with implantable transmitters, we recorded heart rate, electrocardiogram (ECG), body temperature, and locomotor activity continuously in awake, freely moving mice deficient in the thyroid hormone receptor-α1 (TRα1). We have previously reported that the TRα1-deficient mice have a 20% lower mean heart rate and a 0.5°C lower body temperature compared with wild-type control animals. In this study we found that when 3,5,3′-triiodothyronine (T3) was given once a day, there was a parallel increase in heart rate (occurring 1 day later in the TRα1-deficient mice than in controls) and body temperature. Analysis of single-lead ECG revealed a prolonged QRS and Q-Tend time in the TRα1-deficient mice, which was shortened after T3 treatment. Monophasic action potential durations, measured in hearts from anesthetized mice at 90% of repolarization, were significantly prolonged in TRα1-deficient mice. Air-jet stress and a single injection of an anticholinergic agent induced a parallel increase, and a β-adrenergic receptor blocker induced a decrease in heart rate in both groups. There was no difference in β-adrenergic receptor density. The results indicate that the TRα1-deficient mice have a specific defect in intrinsic heart rate regulation.
3
Hadzic, Admir, Jerry Vloka, Nihad Hadzic, Daniel M. Thys e Alan C. Santos. "Nerve Stimulators Used for Peripheral Nerve Blocks Vary in Their Electrical Characteristics". Anesthesiology 98, n. 4 (1 aprile 2003): 969–74. http://dx.doi.org/10.1097/00000542-200304000-00026.
Testo completoAbstract (sommario):
Background Nerve stimulation with a low-intensity electrical current has become a vital part of the performance of peripheral nerve blockade. The purpose of this study was to compare the accuracy and characteristics of peripheral nerve stimulators used in clinical practice in the United States. Methods Fifteen peripheral nerve stimulators were fitted with fresh batteries and set to deliver currents ranging from 0.1 to 4.0 mA into a series of high-tolerance resistance loads ranging from 1 to 100 komega. The current output, stimulus duration, morphology, frequency, and maximum voltage output were studied using a factory-calibrated oscilloscope. Results All peripheral nerve stimulators performed uniformly well when set to deliver currents of 1.0 mA or more into a standard resistance load of 1 or 2 komega. However, at lower currents, the median error (%) increased from 2.4 (-5-144%) at 0.5 mA to 10.4 (-24-180%) at 0.1 mA into a 1 komega load. The morphology of the stimulus was characterized by a regular monophasic square pulse at current outputs of up to 1 mA and at a resistance of 1 komega. The stimulus waveform became particularly distorted as the impedance load was increased. The duration of the default stimulus set by the manufacturer varied from 34.8 to 460 micros among the peripheral nerve stimulators tested. The maximum voltage output ranged from 7.4 to 336 Volts. Conclusions Nerve stimulators used for regional anesthesia vary greatly in accuracy of current output and in manufacturer-selected electrical characteristics (e.g., current duration, stimulating frequency, maximum voltage output).
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Bergmann, Frauke, Kathrin Schwierczek, Stefanie Sollfrank, Andreas Czwalinna, Joseph Erkel, Karl Lackner, Ulrich Walter, Heidi Rossmann e Kerstin Jurk. "Platelet Alpha-Storage Pool Defect Combined with Non-Classic Delta-Storage Pool Deficiency - with a Severe Bleeding Tendency". Blood 128, n. 22 (2 dicembre 2016): 2557. http://dx.doi.org/10.1182/blood.v128.22.2557.2557.
Testo completoAbstract (sommario):
Abstract Aims :We report about a 35 year old male patient with severe and frequent epistaxis and hematoma since infancy. He presented with mild thrombocytopenia and increased mean platelet volume. Von Willebrand's disease and subhemophilia had been excluded. Previously, he was diagnosed with immune thrombocytopenic purpura. He never underwent elective surgery. His parents were asymptomatic. However, his young daughter also suffers from severe bleeding symptoms and was referred to our coagulation outpatient clinic to investigate the bleeding disorder. Methods:Platelet function was assessed by light transmission-, lumi-aggregometry and flow cytometry. Lysates of gel-filtered platelets were analyzed for total granule P-selectin, CD63 and von Willebrand factor (VWF) content by Western blotting and for serotonin levels by ELISA, respectively. Molecular genetic analysis was performed using whole exome sequencing and pyrosequencing. Results: Platelet aggregation in response to ADP was not inducible. Platelet aggregation in response to epinephrine resulted in monophasic curves. Platelet aggregation in response to TRAP-6 or collagen was inducible but impaired and accompanied by disaggregation. In contrast, arachidonic acid- and U46619-induced platelet aggregation as well as ristocetin-induced platelet agglutination/aggregation was within the normal range. Also platelet surface expression of GPIIb/IIIa, GPIb/V/IX, GPVI and CD29 was normal. Activation of GPIIb/IIIa in response to ADP, convulxin or TRAP-6 was inducible but diminished and in response to epinephrine or arachidonic acid normal. P-selectin (alpha-granule marker) and CD63 (dense body/lysosome marker) surface expression was not inducible by thrombin or convulxin and markedly reduced in response to TRAP-6 and arachidonic acid. Immunoblot analysis of isolated platelets demonstrated pronouncedly decreased content of total P-selectin, VWF and CD63. Fluorescent staining of adenine nucleotides by mepacrine in patient's platelet dense bodies and secretion of ATP induced by arachidonic acid (normal aggregation) were absent. However, patient's platelet serotonin levels were within the normal range. The molecular genetic diagnostic showed an undescribed mutation in the GATA1 gene (c.886A>C hemizygot, p.T296P). The bioinformatic check confirmed a pathogenetic importance of this mutation located in the domain I of the C-terminal zinc finger. Conclusion: We describe the first case of a combined platelet alpha- and partial delta-storage pool disorder where the dense granules lack adenine nucleotides but contain normal levels of serotonin - causing a severe bleeding disorder. Disclosures No relevant conflicts of interest to declare.
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Pérez-Silos, Vanessa, Nidia K. Moncada-Saucedo, Víctor Peña-Martínez, Jorge Lara-Arias, Iván A. Marino-Martínez, Alberto Camacho, Víktor J. Romero-Díaz et al. "A Cellularized Biphasic Implant Based on a Bioactive Silk Fibroin Promotes Integration and Tissue Organization during Osteochondral Defect Repair in a Porcine Model". International Journal of Molecular Sciences 20, n. 20 (17 ottobre 2019): 5145. http://dx.doi.org/10.3390/ijms20205145.
Testo completoAbstract (sommario):
In cartilage tissue engineering, biphasic scaffolds (BSs) have been designed not only to influence the recapitulation of the osteochondral architecture but also to take advantage of the healing ability of bone, promoting the implant’s integration with the surrounding tissue and then bone restoration and cartilage regeneration. This study reports the development and characterization of a BS based on the assembly of a cartilage phase constituted by fibroin biofunctionalyzed with a bovine cartilage matrix, cellularized with differentiated autologous pre-chondrocytes and well attached to a bone phase (decellularized bovine bone) to promote cartilage regeneration in a model of joint damage in pigs. BSs were assembled by fibroin crystallization with methanol, and the mechanical features and histological architectures were evaluated. The scaffolds were cellularized and matured for 12 days, then implanted into an osteochondral defect in a porcine model (n = 4). Three treatments were applied per knee: Group I, monophasic cellular scaffold (single chondral phase); group II (BS), cellularized only in the chondral phase; and in order to study the influence of the cellularization of the bone phase, Group III was cellularized in chondral phases and a bone phase, with autologous osteoblasts being included. After 8 weeks of surgery, the integration and regeneration tissues were analyzed via a histology and immunohistochemistry evaluation. The mechanical assessment showed that the acellular BSs reached a Young’s modulus of 805.01 kPa, similar to native cartilage. In vitro biological studies revealed the chondroinductive ability of the BSs, evidenced by an increase in sulfated glycosaminoglycans and type II collagen, both secreted by the chondrocytes cultured on the scaffold during 28 days. No evidence of adverse or inflammatory reactions was observed in the in vivo trial; however, in Group I, the defects were not reconstructed. In Groups II and III, a good integration of the implant with the surrounding tissue was observed. Defects in group II were fulfilled via hyaline cartilage and normal bone. Group III defects showed fibrous repair tissue. In conclusion, our findings demonstrated the efficacy of a biphasic and bioactive scaffold based on silk fibroin and cellularized only in the chondral phase, which entwined chondroinductive features and a biomechanical capability with an appropriate integration with the surrounding tissue, representing a promising alternative for osteochondral tissue-engineering applications.
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"PR561: Comparison of monophasic/biphasic bovine hydroxyapatites on bone regeneration in a rabbit calvarial defect model". Journal of Clinical Periodontology 45 (giugno 2018): 311. http://dx.doi.org/10.1111/jcpe.563_12915.
Testo completo
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"PR562: Comparison of monophasic/biphasic bovine hydroxyapatites on gene expression profiles in a rabbit calvarial defect model". Journal of Clinical Periodontology 45 (giugno 2018): 312. http://dx.doi.org/10.1111/jcpe.564_12915.
Testo completo
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Cong, Yu, Zhong Liang, Ni Jianping, Hu Wenyue, Ghamor-Amegavi Edem Prince e Xiangfeng Zhang. "Rational design and fabrication of monophasic bioceramic microspheres with enhanced mechanical and biological performances in reconstruction of segmental bone defect". Medical & Biological Engineering & Computing, 18 aprile 2022. http://dx.doi.org/10.1007/s11517-022-02571-7.
Testo completoTesi sul tema "Defaut monophase"
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FERRACCI, PHILIPPE. "Etude des regimes transitoires a l'etablissement d'un defaut monophase sur reseau d'energie triphase moyenne tension a neutre compense". Paris 11, 1995. http://www.theses.fr/1995PA112272.
Testo completoAbstract (sommario):
La proportion de cables moyenne tension se developpe. Edf envisage de generaliser l'emploi de bobine de compensation dans les reseaux moyenne tension mixte. Ainsi la plupart des defauts monophases sont autoextincteurs et la plupart des defauts permanents sont des defauts a arc intermittent. Il est donc necessaire que les protections employees pour selectionner le depart en defaut exploitent le regime transitoire qui se produit a l'apparition du defaut. Pour etudier ces regimes transitoires, un circuit electrique equivalent simple, utilisant les composantes naturelles du reseau est realise. Sa structure permet une comprehension physique et intuitive des phenomenes. Ce modele est valide par confrontations avec differents enregistrements effectues sur un reseau d'edf ainsi qu'avec des simulations emtp. Dans les cas des faibles et des grandes resistances de defaut, les relations analytiques permettant de correler les caracteristiques du regime transitoire et les parametres du reseau sont proposees. La signification physique des differentes composantes du regime transitoire est mis en evidence. En dehors de ce domaine le probleme doit etre resolu numeriquement. L'influence des differents parametres du reseau sur les caracteristiques du regime transitoire ainsi que celle des composantes sur l'energie homopolaire transitee est etudiee. Les connaissances des regimes transitoires apportees par l'etude, doit permettre de definir avec plus de precision les besoins fonctionnels en matiere de protection sur les reseaux a neutre compense et de verifier le bon fonctionnement de ces protections
2
Welfonder, Till. "Localisation de défauts monophasés dans les réseaux de distribution à neutre compensé". Grenoble INPG, 1998. http://www.theses.fr/1998INPG0053.
Testo completoAbstract (sommario):
La mise à la terre du point neutre des réseaux de distribution par une bobine de compensation réduit le courant de défaut lors d'un défaut monophasé, ce qui est le type de défaut le plus souvent rencontré dans l'exploitation. Cette mesure améliore la qualité de service, mats rend la détection et la localisation de défauts plus difficiles. Cette thèse traite de la localisation de défauts à faible résistance, auto-extincteurs ou permanents dans les réseaux compensés arborescents. Les phénomènes transitoires lors d'un défaut sont étudiés et une nouvelle approche pour la localisation est développée. L'approche est basée sur l'exploitation des signaux au niveau du poste de transformation HT/MT à une fréquence de résonance caractéristique. Un algorithme de localisation de défaut a été conçu, réalisé et testé. Son fonctionnement est validé avec des simulations de réseau et avec des enregistrements de défauts réels. L'influence des différents paramètres sur la précision de l'algorithme est examinée et expliquéeThe distribution system neutral point grounding by a compensation coil reduces the fault current due to a single phase fault. Which ÎS the most fréquent fault type in practice. Fhis means improves the supply quality, however, it makes tauli détection and local i diffieuh fhi thesis deals with fault location of low résistive self-extinguishing or permanent earth faults in radial, neutral compensated Systems. Transient fault phenomena are studied and a new fault location approach is developed. The approach is based on the exploitation of a chaiaeterisric résonance frequency of signais measured in the HV/MV ration. An algorithm has been created, developed and tested. It is validated with po system simulations and with measured fault data of real faults. The influence of différent parameters on the algorithm accuracy is examined and explairsed
3
Ammari, Ahmed Chiheb. "Comportement électromécanique d'une machine synchrone soumise à un cycle de réenclenchement monophasé". Grenoble INPG, 1996. http://www.theses.fr/1996INPG0057.
Testo completoAbstract (sommario):
Dans un réseau d'énergie électrique, les génératrices synchrones sont soumises à des régimes transitoires qui conditionnent leur stabilité et leur tenue mécanique. Nous considérons le cas d'une centrale hydroélectrique, équipée de machines synchrones à pôles saillants pouvant fonctionner en générateur (turbine) et en moteur (pompe). Une telle centrale est généralement reliée au réseau général par une ligne à haute tension qui peut être affectée par des défauts fugitifs. Nous étudions le comportement d'une machine synchrone, lorsque la liaison, affectée d'un court-circuit monophasé, est temporairement ouverte puis réenclenchée. Lors d'un tel cycle, la machine fonctionne en régime biphasé au cours duquel elle peut perdre le synchronisme ; si le synchronisme est maintenu, le réenclenchement de la phase ouverte engendre des couples électromagnétiques assez élevés, qui peuvent compromettre la tenue mécanique de la machine. Ces deux aspects sont étudiés analytiquement et numériquement ; les conditions de maintien du synchronisme et l'amplitude des couples transitoires sont déterminés en fonction des paramètres de la machine et de la liaison. Enfin, une application à quelques cas de centrales hydroélectriques de pompage française est présentée
4
ʿAllūš, I. S. "Classification et caracterisation des defauts monophases sur les reseaux de distribution hta". Paris 6, 1997. http://www.theses.fr/1997PA066600.
Testo completoAbstract (sommario):
Cette these est consacree a la classification et la caracterisation des defauts monophases sur les reseaux hta. Bien identifier les defauts, pour mieux alimenter les clients, devrait permettre, a terme, d'optimiser la maintenance des reseaux et d'augmenter la duree de vie des ouvrages. Actuellement, dans les postes htb/hta qui sont instrumentes, l'acquisition des signaux se fait au mieux avec une frequence d'echantillonnage de 10 khz. Elle est plus couramment egale a 3 khz, ce qui semble insuffisant pour la reconnaissance des defauts. De plus, pour la plupart des signaux qui sont disponibles, on ne dispose pas de d'information quant a la nature physique du defaut. Afin d'obtenir les informations necessaires a l'etude envisagee, la direction des etudes et recherches d'electricite de france s'est dotee d'un reseau experimental hta situe au laboratoire de genie electrique des renardieres. Celui-ci a permis de provoquer et de reproduire plusieurs plus de 700 echantillons de defauts monophases en regime de neutre resistif et autant en regime de neutre compense. Quatre types de defauts ont ete consideres : les contacts directs sur bitume, sur terre et sur herbe, et les contournements d'isolateurs. Les trois premiers pour des raisons de securite (risques d'electrocution et d'incendie) et les quatriemes parcequ'ils constituent des signes precurseurs d'avaries plus importantes. Les experimentations ont ete faites en deux points differents du reseau experimental, afin de pouvoir etudier l'influence de la localisation du defaut. Differentes methodes de traitement du signal (prony, transformee de fourier, decomposition en ondelettes, distribution pseudo wigner ville lissee) ont ete utilisees afin de preparer les donnees a l'utilisation de deux methodes statistiques : l'analyse en composantes principales et l'analyse discriminante. Cette approche a permis de demontrer qu'il existait des possibilites de discrimination des defauts suivant leur origine physique, a basses frequences et a partir du poste htb/hta. Celles-ci semblent plus importantes pour les vecteurs descripteurs issus du courant residuel que pour ceux obtenus a partir de la tension de la phase en defaut. Elles ouvrent de nouvelles perspectives quant a la surveillance et la maintenance des reseaux de distribution hta. Precurseurs d'avaries plus importantes. Les experimentations ont ete faites en deux points differents du reseau experimental, afin de pouvoir etudier l'influence de la localisation du defaut. Differentes methodes de traitement du signal (prony, transformee de fourier, decomposition en ondelettes, distribution pseudo wigner ville lissee ) ont ete utilisees afin de preparer les donnees a l'utilisation de deux methodes statistiques : l'analyse en composantes principales et l'analyse discriminante. Cette approche a permis de demontrer qu'il existait des possibilites de discrimination des defauts suivant leur origine physique, a basses frequences et a partir du poste htb/hta. Celles-ci semblent plus importantes pour les vecteurs descripteurs issus du courant residuel que pour ceux obtenus a partir de la tension de la phase en defaut. Elles ouvrent de nouvelles perspectives quant a la surveillance et la maintenance des reseaux de distribution hta.
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VALENTI, ARNAUD. "Localisation de defauts monophases a la terre dans les reseaux de distribution hta". Paris 6, 2000. http://www.theses.fr/2000PA066465.
Testo completoAbstract (sommario):
Dans le but de reduire le nombre de coupures sur les reseaux hta et d'ameliorer la qualite de la fourniture, la division r&d de edf a engage des actions sur la localisation a distance des defauts monophases a la terre. La technique de localisation envisagee ici est fondee sur l'analyse des phenomenes de propagation et de reflexion des ondes dans ces reseaux electriques arborescents. Elle est independante du regime de neutre et peut etre etendue a n'importe quel type de defaut. L'apparition d'un defaut genere un echelon (tension + courant) qui va se propager au sein du reseau et se reflechir a chaque rupture d'impedance et notamment au lieu du defaut pour finalement engendrer des ondes stationnaires. Le courant et la tension contiennent ainsi l'un et l'autre au moins une frequence caracteristique de la position du defaut. La relation etablie entre cette frequence et le lieu du defaut resulte d'une etude approfondie de l'equation differentielle dites des telegraphistes, appliquee a un systeme de lignes triphasees. Malheureusement, l'algorithme developpe ici pour fournir la position du defaut au sein du reseau necessite actuellement la connaissance au prealable du troncon en defaut ainsi que la connaissance des impedances a chaque extremite du reseau. De plus, ses performances en simulation sur des topologies de reseau hta reels ne sont pas tres bonnes a cause justement de l'arborescence de ce type de reseau. Cette technique de localisation de defaut haute frequence devient cependant opportune dans le cas de reseaux dont l'arborescence reste simple. Ce resultat est valide par des campagnes de mesures experimentales. Finalement, une methode de localisation de defaut basee sur les phenomenes de propagation et reflexion des ondes parait difficilement utilisable dans le cas de reseaux hta arborescents, mais elle peut s'averer pertinente pour localiser un defaut dans un reseau htb ou dans un cable souterrain meme s'il y a une derivation.