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  1. 7 CFR 1485.25 - Failure to make required contribution.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Failure to make required contribution. 1485.25... FOR U.S. AGRICULTURAL COMMODITIES Market Access Program § 1485.25 Failure to make required... Participant's required contribution is specified as a dollar amount and the MAP Participant does not make the...

  2. 7 CFR 1485.21 - Failure to make required contribution.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Failure to make required contribution. 1485.21 Section 1485.21 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT... MARKETS FOR AGRICULTURAL COMMODITIES Market Access Program § 1485.21 Failure to make required contribution...

  3. The contribution of hibernation to heart failure.

    PubMed

    Camici, Paolo G; Rimoldi, Ornella E

    2004-01-01

    For many years the functional sequelae of chronic coronary artery disease (CAD) were considered irreversible. Evidence accrued over the past three decades proves that this concept is not necessarily true. Non-randomised studies demonstrated that coronary revascularisation (CR) confers symptomatic and prognostic benefits to patients with CAD and heart failure. Based on available studies, one can assume that the beneficial effect of CR in heart failure derives primarily from recovery of contractile function in 'hibernating myocardium' (HM), i.e., chronically dysfunctional, but viable, myocardium subtended by stenosed coronary arteries which recovers after CR. Cardiac imaging with echocardiography, single photon and positron emission tomography (PET) and magnetic resonance allows the identification of HM. These techniques have comparable predictive values in patients with moderate left ventricular impairment. PET studies have shown that resting myocardial blood flow is preserved in most cases of HM while its main feature is a severe impairment of coronary flow reserve. Thus, the pathophysiology of HM is more complex than initially postulated. Recent evidence that repetitive ischaemia in patients can be cumulative and lead to more severe and prolonged stunning, lends further support to the hypothesis that, at least initially, stunning and HM are two facets of the same coin.

  4. The Contributing Factors of Pragmatic Failure in China's ELT Classrooms

    ERIC Educational Resources Information Center

    Shen, Qi-yuan

    2013-01-01

    Pragmatic failure is the inability to understand what is meant by what is said, which can often lead to misunderstanding or confusion in cross-cultural communication. For this reason, the present article explores the contributing factors of pragmatic failure in China's ELT Classrooms. According to the exploration, the following factors are found…

  5. Abdominal contributions to cardiorenal dysfunction in congestive heart failure.

    PubMed

    Verbrugge, Frederik H; Dupont, Matthias; Steels, Paul; Grieten, Lars; Malbrain, Manu; Tang, W H Wilson; Mullens, Wilfried

    2013-08-06

    Current pathophysiological models of congestive heart failure unsatisfactorily explain the detrimental link between congestion and cardiorenal function. Abdominal congestion (i.e., splanchnic venous and interstitial congestion) manifests in a substantial number of patients with advanced congestive heart failure, yet is poorly defined. Compromised capacitance function of the splanchnic vasculature and deficient abdominal lymph flow resulting in interstitial edema might both be implied in the occurrence of increased cardiac filling pressures and renal dysfunction. Indeed, increased intra-abdominal pressure, as an extreme marker of abdominal congestion, is correlated with renal dysfunction in advanced congestive heart failure. Intriguing findings provide preliminary evidence that alterations in the liver and spleen contribute to systemic congestion in heart failure. Finally, gut-derived hormones might influence sodium homeostasis, whereas entrance of bowel toxins into the circulatory system, as a result of impaired intestinal barrier function secondary to congestion, might further depress cardiac as well as renal function. Those toxins are mainly produced by micro-organisms in the gut lumen, with presumably important alterations in advanced heart failure, especially when renal function is depressed. Therefore, in this state-of-the-art review, we explore the crosstalk between the abdomen, heart, and kidneys in congestive heart failure. This might offer new diagnostic opportunities as well as treatment strategies to achieve decongestion in heart failure, especially when abdominal congestion is present. Among those currently under investigation are paracentesis, ultrafiltration, peritoneal dialysis, oral sodium binders, vasodilator therapy, renal sympathetic denervation and agents targeting the gut microbiota.

  6. Colles-Stokes contributions to the concept of heart failure.

    PubMed

    Ventura, H O; Mehra, M R

    1998-06-15

    "Colles fracture," "Colles law," "Stokes-Adams syndrome," "Cheyne-Stokes respiration," and "Corrigan pulse" are some of the contributions of the Irish school that are utilized for teaching purposes in medical schools and training programs, as well as in daily practice of medicine. We wish to add an important description by Drs. Colles and Stokes that personifies the considerable personal contributions of these 2 physicians in our understanding of the pathophysiologic expression of the syndrome of heart failure. The clinical-pathologic correlation of the disease that affected Dr. Colles is well described by Dr. Stokes in his treatise Diseases of the Heart and the Aorta. He recognized the cyclical nature of frequent decompensations in heart failure, the relation of clinical worsening in conjunction with reduced urine output, as well as the importance of reestablishing urinary flow to achieve a decrease in dyspnea. Dr. Colles also demonstrated a profound clinical insight when he noticed, first, that his affliction was "eventually a fatal disease and that remedies that work may lose effect over time," illustrating an observation that has stood the test of time and, secondly, when he told Dr. Smith "... I would direct particular attention to the heart and the lungs ... and the swelling in the right hypochondrium ... I suspect that there is some connexion between this swelling of the hypochondrium and the diseased state of the heart." We believe that the Colles-Stokes contributions, both in the clinical as well as the clinical-pathologic arenas, are one of the landmark descriptions that helped to evolve the concept of the syndrome of heart failure.

  7. Factors contributing to migraine headache surgery failure and success.

    PubMed

    Larson, Kelsey; Lee, Michelle; Davis, Janine; Guyuron, Bahman

    2011-11-01

    The purpose of this study was to identify factors that contribute to migraine headache surgery failure and success. A retrospective chart review was conducted of patients who underwent surgery for migraine headaches performed by the senior author (B.G.) and had at least 11 months of follow-up. The study population included three groups: migraine surgery success, improvement, and failure. Thirty-six unique data points were collected for each patient. A total of 169 patients met inclusion criteria. Of these, 66 patients comprised the migraine surgery success group (S, complete elimination of migraine headaches); 67 comprised the migraine surgery improvement group (I, >50 percent reduction in migraine frequency, intensity, or duration); and 36 comprised the migraine surgery failure group (F, <50 percent reduction in migraine frequency, intensity, or duration). Significant differences among the groups included age at surgery (S>I, p=0.02), migraine frequency (SI, p=0.003; S>F, p=0.04), history of head or neck injury (SI, p=0.02), increased intraoperative bleeding (SF, p=0.0006; I>F, p=0.0004), site II (S>F, p=0.015), single operative site (SI, p=0.05; S>F, p=0.04). Factors associated with migraine surgery failure include increased intraoperative bleeding and surgery on fewer trigger sites. Factors associated with migraine surgery success are older age of migraine onset, higher rate of visual symptoms versus improvement group, surgery at site I or II, and deactivating all four operative sites. Risk, III.

  8. Quantifying Pilot Contribution to Flight Safety during Hydraulic Systems Failure

    NASA Technical Reports Server (NTRS)

    Kramer, Lynda J.; Etherington, Timothy J.; Bailey, Randall E.; Kennedy, Kellie D.

    2017-01-01

    Accident statistics cite the flight crew as a causal factor in over 60% of large transport aircraft fatal accidents. Yet, a well-trained and well-qualified pilot is acknowledged as the critical center point of aircraft systems safety and an integral safety component of the entire commercial aviation system. The latter statement, while generally accepted, cannot be verified because little or no quantitative data exists on how and how many accidents/incidents are averted by crew actions. A joint NASA/FAA high-fidelity motion-base human-in-the-loop test was conducted using a Level D certified Boeing 737-800 simulator to evaluate the pilot's contribution to safety-of-flight during routine air carrier flight operations and in response to aircraft system failures. To quantify the human's contribution, crew complement (two-crew, reduced crew, single pilot) was used as the independent variable in a between-subjects design. This paper details the crew's actions, including decision-making, and responses while dealing with a hydraulic systems leak - one of 6 total non-normal events that were simulated in this experiment.

  9. Caracterisation des etats de surface par teledetection infrarouge thermique multispectrale: Contribution a l'etude des conditions de viabilite hivernale

    NASA Astrophysics Data System (ADS)

    Chagnon, Frederic

    valeur de temperature corrigee, une verification prealable ayant permis de determiner la precision du TES a 0,5 °C, nous avons determine la precision relative des deux autres methodes par rapport a celle du TES. Pour les deux methodes TISI et ITR, la correction de temperature radiative a donne un ecart moyen similaire de l'ordre de --1,2 °C, avec une etendue d'ecart allant de ---0,5 a --2,2 °C. L'experience realisee a permis de presenter un prototype operationnel de mesure de la temperature de surface permettant en meme temps la caracterisation de la surface mesuree. L'extraction de ces deux types d'informations a partir d'une meme serie de mesures est une innovation. La banque d'emissivite spectrale mesuree sur le terrain est aussi une contribution de ce projet. Teledetection -- Infrarouge thermique -- Temperature de surface -- Neige -- Glace -- Meteorologie routiere

  10. 7 CFR 1485.25 - Failure to make required contribution.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... contribution. A MAP Participant's required contribution will be specified in the approval letter. If the MAP Participant's required contribution is specified as a dollar amount and the MAP Participant does not make the required contribution, the MAP Participant shall pay to CCC in dollars the difference between the...

  11. 7 CFR 1485.21 - Failure to make required contribution.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... required contribution. An MAP participant's contribution requirement will be specified in the MAP.... The MAP participant shall pay to CCC in dollars the difference between the amount actually contributed and the amount specified in the allocation approval letter. An MAP participant shall remit...

  12. 7 CFR 1485.21 - Failure to make required contribution.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... required contribution. An MAP participant's contribution requirement will be specified in the MAP.... The MAP participant shall pay to CCC in dollars the difference between the amount actually contributed and the amount specified in the allocation approval letter. An MAP participant shall remit...

  13. Contribution aux Methodes Analytiques des Substances a L'aide de Faisceaux de Particules Chargees

    NASA Astrophysics Data System (ADS)

    Saidi, Abdelmajid

    Nous avons vu les possibilites d'analyse par particules chargees des aerosols recueillis sur des filtres de type MILLIPORE. La meme technique a ete utilisee pour des filtres ayant servi a la filtration de l'eau du fleuve Saint-laurent. Deux techniques ont ete utilisees: (1) FAST (Forward Alpha Scattering Technique): pour analyser l'hydrogene, le carbone, l'oxygene et puis l'azote. Des alpha de 12 MeV ont ete utilises. (2) PIXE (Particle Induced X-ray Emission): pour analyser les elements moyens et lourds, dans ce cas des protons de 3 MeV ainsi que des ions d'argon de 1 et 1.6 MeV ont ete utilises. Les etudes ont montre que sous vide, la majorite des problemes proviennent des dommages causes par l'echauffement du a l'impact du faisceau sur le filtre. L'analyse quantitative par l'intermediaire du faisceau extrait peut presenter des difficultes en ce qui concerne les elements legers pour lesquels l'absorption des rayonnements caracteristiques dans l'atmosphere externe est importante. Les ions lourds se pretent mal aux analyses des aerosols du fait de leur limite de sensibilite. L'analyse directe de liquides par des protons est particulierement interessante puisqu'elle ne necessite aucune preparation prealable des echantillons. A cet effet, un programme de calcul de concentration des elements dans la solution a analyser a ete mis au point. Nous avons determine la limite de sensibilite de la methode PIXE pour les cibles minces (filtre) et pour le cas ou la matrice est de l'eau. Enfin, la technique FAST peut etre un complement de la technique PIXE.

  14. Contributions à la Définition des Besoins scientifiques et des Solutions instrumentales du Projet Planck-HFI

    NASA Astrophysics Data System (ADS)

    Piat, Michel

    2000-10-01

    Le satellite Planck, dont le lancement est prévu en 2007, constituera la troisième génération d'instruments dédiés à l'observation de l'anisotropie du corps noir cosmologique, avec une sensibilité environ 600 fois meilleurs que COBE. C'est grâce à l'évolution des technologies instrumentales au niveau des détecteurs bolométriques, de la cryogénie et de l'électronique à faible bruit que cette avancée considérable est possible. Une mesure aussi sensible demande la maîtrise de plusieurs aspects intimement liés: l'acquisition de signaux bas niveau, la production et la maîtrise des basses températures, le contrôle du rayonnement parasite et la stabilité de la mesure. Ce mémoire traite des relations entre ces différents aspects mais aussi des avancées technologiques auxquelles j'ai contribué dans chacun de ces domaines. Les deux premiers chapitres sont consacrés à la description d'une part du contexte scientifique et d'autre part du satellite Planck et de l'instrument HFI (High Frequency Instrument). Le troisième chapitre expose la mise au point et l'utilisation du cryostat Symbol qui m'a permis de tester et de valider des solutions techniques pour HFI. Le quatrième chapitre concerne la chaîne de détection bolométrique et le développement d'un système symétrique pour HFI. Le problème de la lumière parasite est traité en chapitre 5 et conduit aux spécifications de stabilité de température des différents étages de Planck-HFI. Ceci m'a amené à étudier les solutions technologiques permettant d'atteindre ces spécifications auniveau de l'étage 100mK supportant les bolomètres, sujet traité en chapitre 6, alors que le chapitre 7 est consacré à la thermométrie HFI du point de vue de la sensibilité et de la précision. Enfin, le dernier chapitre montre comment ces progrès instrumentaux rendent possible la détection par Planck-HFI de l'effet dipolaire dans le Fond Diffus Extragalactique Sub-millimétrique (FDES) provenant de

  15. Equipment failures and their contribution to industrial incidents and accidents in the manufacturing industry.

    PubMed

    Bourassa, Dominic; Gauthier, François; Abdul-Nour, Georges

    2016-01-01

    Accidental events in manufacturing industries can be caused by many factors, including work methods, lack of training, equipment design, maintenance and reliability. This study is aimed at determining the contribution of failures of commonly used industrial equipment, such as machines, tools and material handling equipment, to the chain of causality of industrial accidents and incidents. Based on a case study which aimed at the analysis of an existing pulp and paper company's accident database, this paper examines the number, type and gravity of the failures involved in these events and their causes. Results from this study show that equipment failures had a major effect on the number and severity of accidents accounted for in the database: 272 out of 773 accidental events were related to equipment failure, where 13 of them had direct human consequences. Failures that contributed directly or indirectly to these events are analyzed.

  16. Liver congestion in heart failure contributes to inappropriately increased serum hepcidin despite anemia.

    PubMed

    Ohno, Yukako; Hanawa, Haruo; Jiao, Shuang; Hayashi, Yuka; Yoshida, Kaori; Suzuki, Tomoyasu; Kashimura, Takeshi; Obata, Hiroaki; Tanaka, Komei; Watanabe, Tohru; Minamino, Tohru

    2015-01-01

    Hepcidin is a key regulator of mammalian iron metabolism and mainly produced by the liver. Hepcidin excess causes iron deficiency and anemia by inhibiting iron absorption from the intestine and iron release from macrophage stores. Anemia is frequently complicated with heart failure. In heart failure patients, the most frequent histologic appearance of liver is congestion. However, it remains unclear whether liver congestion associated with heart failure influences hepcidin production, thereby contributing to anemia and functional iron deficiency. In this study, we investigated this relationship in clinical and basic studies. In clinical studies of consecutive heart failure patients (n = 320), anemia was a common comorbidity (41%). In heart failure patients without active infection and ongoing cancer (n = 30), log-serum hepcidin concentration of patients with liver congestion was higher than those without liver congestion (p = 0.0316). Moreover, in heart failure patients with liver congestion (n = 19), the anemia was associated with the higher serum hepcidin concentrations, which is a type of anemia characterized by induction of hepcidin. Subsequently, we produced a rat model of heart failure with liver congestion by injecting monocrotaline that causes pulmonary hypertension. The monocrotaline-treated rats displayed liver congestion with increase of hepcidin expression at 4 weeks after monocrotaline injection, followed by anemia and functional iron deficiency observed at 5 weeks. We conclude that liver congestion induces hepcidin production, which may result in anemia and functional iron deficiency in some patients with heart failure.

  17. The Contribution of Counseling Providers to the Success or Failure of Marriages

    ERIC Educational Resources Information Center

    Ansah-Hughes, Winifred

    2015-01-01

    This study is an investigation into the contribution of counseling providers to the success or failure of marriages. The purposive and the simple random sampling methods were used to select eight churches and 259 respondents (married people) in the Techiman Municipality. The instrument used to collect data was a 26-item questionnaire including a…

  18. Identification of the human factors contributing to maintenance failures in a petroleum operation.

    PubMed

    Antonovsky, Ari; Pollock, Clare; Straker, Leon

    2014-03-01

    This research aimed to identify the most frequently occurring human factors contributing to maintenance-related failures within a petroleum industry organization. Commonality between failures will assist in understanding reliability in maintenance processes, thereby preventing accidents in high-hazard domains. Methods exist for understanding the human factors contributing to accidents. Their application in a maintenance context mainly has been advanced in aviation and nuclear power. Maintenance in the petroleum industry provides a different context for investigating the role that human factors play in influencing outcomes. It is therefore worth investigating the contributing human factors to improve our understanding of both human factors in reliability and the factors specific to this domain. Detailed analyses were conducted of maintenance-related failures (N = 38) in a petroleum company using structured interviews with maintenance technicians. The interview structure was based on the Human Factor Investigation Tool (HFIT), which in turn was based on Rasmussen's model of human malfunction. A mean of 9.5 factors per incident was identified across the cases investigated.The three most frequent human factors contributing to the maintenance failures were found to be assumption (79% of cases), design and maintenance (71%), and communication (66%). HFIT proved to be a useful instrument for identifying the pattern of human factors that recurred most frequently in maintenance-related failures. The high frequency of failures attributed to assumptions and communication demonstrated the importance of problem-solving abilities and organizational communication in a domain where maintenance personnel have a high degree of autonomy and a wide geographical distribution.

  19. Contribution des avortements et des grossesses extra-utérines dans la mortalité maternelle dans trois hôpitaux universitaires de Yaoundé

    PubMed Central

    Kamga, Danielle Victoire Tiako; Nana, Philip Njotang; Fouelifack, Florent Ymele; Fouedjio, Jeanne Hortence

    2017-01-01

    Introduction L'organisation mondiale de santé (OMS) estime que chaque année dans le monde 585 000 femmes meurent de complications liés à la grossesse, à l'accouchement, aux suites de couche et à l'avortement (ce dernier contribuant pour 13% des décès maternels). La GEU est responsable de 10% de mortalité maternelle au premier trimestre de la grossesse. Le taux de mortalité maternelle reste élevé au Cameroun, estimé à 782 pour 100 000 naissances vivantes selon EDS-MICS 2011. La contribution de ces deux entités dans la mortalité maternelle étant peu documentée dans notre pays, nous avons entrepris de réaliser cette étude avec pour objectif d'évaluer la contribution des avortements et des GEU dans la mortalité maternelle au Cameroun. Méthodes il s'agissait d'une étude rétrospective et analytique. Nous avons colligé tous les dossiers des patientes enceintes et décédées avant la 28ème semaine de grossesse, dans trois hôpitaux universitaires: Hôpital Central de Yaoundé (HCY), Hôpital Gynéco-Obstétrique et Pédiatrique de Yaoundé (HGOPY), Centre Hospitalier et Universitaire (CHU), sur la période allant du 1er juin 2011 au 31 mai 2016, soit sur cinq ans. Les données étaient compilées sur une fiche technique préétablie et testée, saisies en utilisant le logiciel CS pro 6.2 et analysées par le logiciel SPSS 20. Les tests statistiques de comparaison utilisés étaient le Khi 2 et le test de Fischer en fonction des effectifs. Le seuil de significativité était retenu pour P < 005. Résultats Tous avons enregistré 524 décès maternels pour 31116 naissances vivantes, soit un taux de mortalité maternelle (TMM) de 1538.9/100 000 naissances vivantes. Sur les 524 décès maternels, 414 dossiers étaient exploitables, parmi lesquels, 100 (soit 24.2%) concernaient les avortements et 24 (soit 5.8%) concernaient les grossesses extra-utérines, ces 2 entités contribuaient ainsi pour 30% de décès maternels (124 dossiers sur 414). L

  20. Quantification des besoins en intrants antipaludiques: contribution à l'actualisation des hypothèses pour la quantification des intrants de prise en charge des cas de paludisme grave en République Démocratique du Congo

    PubMed Central

    Likwela, Joris Losimba; Otokoye, John Otshudiema

    2015-01-01

    Les formes graves de paludisme à Plasmodium falciparum sont une cause majeure de décès des enfants de moins de 5 ans en Afrique Sub-saharienne. Un traitement rapide dépend de la disponibilité de médicaments appropriés au niveau des points de prestation de service. La fréquence des ruptures de stock des commodités antipaludiques, en particuliers celles utilisées pour le paludisme grave, avait nécessité une mise à jour des hypothèses de quantification. Les données issues de la collecte de routine du PNLP de 2007 à 2012 ont été comparées à celles rapportés par d'autres pays africains et utilisées pour orienter les discussions au cours d'un atelier organisé par le PNLP et ses partenaires techniques et financiers afin de dégager un consensus national. La proportion des cas de paludisme rapportés comme grave en RDC est resté autour d'une médiane de 7% avec un domaine de variation de 6 à 9%. Hormis la proportion rapportée au Kenya (2%), les pays africains ont rapporté une proportion de cas grave variant entre 5 et 7%. Il apparaît que la proportion de 1% précédemment utilisée pour la quantification en RDC a été sous-estimée dans le contexte de la gestion des cas graves sur terrain. Un consensus s'est dégagé autour de la proportion de 5% étant entendu que des efforts de renforcement des capacités seraient déployés afin d'améliorer le diagnostic au niveau des points de prestation des services. PMID:26213595

  1. Mineralocorticoid Receptor Activation Contributes to the Supine Hypertension of Autonomic Failure.

    PubMed

    Arnold, Amy C; Okamoto, Luis E; Gamboa, Alfredo; Black, Bonnie K; Raj, Satish R; Elijovich, Fernando; Robertson, David; Shibao, Cyndya A; Biaggioni, Italo

    2016-02-01

    Primary autonomic failure is characterized by disabling orthostatic hypotension, but at least half of these patients have paradoxical supine hypertension. Renin-angiotensin mechanisms were not initially thought to contribute to this hypertension because plasma renin activity is often undetectable in autonomic failure. Plasma aldosterone levels are normal, however, and we recently showed that plasma angiotensin II is elevated and acts at AT1 (angiotensin type 1) receptors to contribute to hypertension in these patients. Because aldosterone and angiotensin II can also bind mineralocorticoid receptors to elevate blood pressure, we hypothesized that mineralocorticoid receptor activation plays a role in the hypertension of autonomic failure. To test this hypothesis, we determined the acute effects of the mineralocorticoid receptor antagonist eplerenone (50 mg, oral) versus placebo on supine blood pressure in a randomized, double-blind, crossover study. Medications were given at 8:00 pm with blood pressure recorded every 2 hours for 12 hours. Ten primary autonomic failure patients with supine hypertension completed this study (7 pure autonomic failure, 2 multiple system atrophy, 1 parkinson's disease; 7 male; 70±2 years of age). Eplerenone maximally reduced supine systolic blood pressure by 32±6 mm Hg at 8 hours after administration (versus 8±10 mm Hg placebo, P=0.016), with no effect on nocturia (12-hour urine volume: 985±134 mL placebo versus 931±94 mL eplerenone, P=0.492; nocturnal weight loss: -1.19±0.15 kg placebo versus -1.18±0.15 kg eplerenone, P=0.766). These findings suggest that inappropriate mineralocorticoid receptor activation contributes to the hypertension of autonomic failure, likely independent of canonical mineralocorticoid effects, and provides rationale for use of eplerenone in these patients. © 2015 American Heart Association, Inc.

  2. 617-R2 Mineralocorticoid Receptor Activation Contributes to the Supine Hypertension of Autonomic Failure

    PubMed Central

    Arnold, Amy C.; Okamoto, Luis E.; Gamboa, Alfredo; Black, Bonnie K.; Raj, Satish R.; Elijovich, Fernando; Robertson, David; Shibao, Cyndya A.; Biaggioni, Italo

    2016-01-01

    Primary autonomic failure is characterized by disabling orthostatic hypotension; but at least half of these patients have paradoxical supine hypertension. Renin-angiotensin mechanisms were not initially thought to contribute to this hypertension, as plasma renin activity is often undetectable in autonomic failure. Plasma aldosterone levels are normal, however, and we recently showed that plasma angiotensin II is elevated and acts at AT1 receptors to contribute to hypertension in these patients. Since aldosterone and angiotensin II can also bind mineralocorticoid receptors to elevate blood pressure, we hypothesized that mineralocorticoid receptor activation plays a role in the hypertension of autonomic failure. To test this hypothesis, we determined the acute effects of the mineralocorticoid receptor antagonist eplerenone (50 mg, oral) versus placebo on supine blood pressure in a randomized, double blind, crossover study. Medications were given at 8:00 PM with blood pressure recorded every 2 hours for 12 hours. Ten primary autonomic failure patients with supine hypertension completed this study (7 Pure Autonomic Failure, 2 Multiple System Atrophy, 1 Parkinson’s disease; 7 male; 70±2 years of age). Eplerenone maximally reduced supine systolic blood pressure by 32±6 mmHg at 8 hours after administration (vs. 8±10 mmHg placebo, p=0.016), with no effect on nocturia (12-hour urine volume: 985±134 placebo vs. 931±94 ml eplerenone, p=0.492; nocturnal weight loss: −1.19±0.15 placebo vs. −1.18±0.15 kg eplerenone, p=0.766). These findings suggest that inappropriate mineralocorticoid receptor activation contributes to the hypertension of autonomic failure, likely independent of canonical mineralocorticoid effects, and provides rationale for use of eplerenone in these patients. PMID:26644241

  3. Angiotensin II, independent of plasma renin activity, contributes to the hypertension of autonomic failure.

    PubMed

    Arnold, Amy C; Okamoto, Luis E; Gamboa, Alfredo; Shibao, Cyndya; Raj, Satish R; Robertson, David; Biaggioni, Italo

    2013-03-01

    At least half of primary autonomic failure patients exhibit supine hypertension, despite profound impairments in sympathetic activity. Although the mechanisms underlying this hypertension are unknown, plasma renin activity is often undetectable, suggesting renin-angiotensin (Ang) pathways are not involved. However, because aldosterone levels are preserved, we tested the hypothesis that Ang II is intact and contributes to the hypertension of autonomic failure. Indeed, circulating Ang II was paradoxically increased in hypertensive autonomic failure patients (52±5 pg/mL, n=11) compared with matched healthy controls (27±4 pg/mL, n=10; P=0.002), despite similarly low renin activity (0.19±0.06 versus 0.34±0.13 ng/mL per hour, respectively; P=0.449). To determine the contribution of Ang II to supine hypertension in these patients, we administered the AT(1) receptor blocker losartan (50 mg) at bedtime in a randomized, double-blind, placebo-controlled study (n=11). Losartan maximally reduced systolic blood pressure by 32±11 mm Hg at 6 hours after administration (P<0.05), decreased nocturnal urinary sodium excretion (P=0.0461), and did not worsen morning orthostatic tolerance. In contrast, there was no effect of captopril on supine blood pressure in a subset of these patients. These findings suggest that Ang II formation in autonomic failure is independent of plasma renin activity, and perhaps Ang-converting enzyme. Furthermore, these studies suggest that elevations in Ang II contribute to the hypertension of autonomic failure, and provide rationale for the use of AT(1) receptor blockers for treatment of these patients.

  4. Dysregulated long intergenic non-coding RNA modules contribute to heart failure

    PubMed Central

    Zhang, Xinxin; Yu, Fulong; Lan, Yujia; Xu, Jinyuan; Pang, Bo; Han, Dong; Xiao, Yun; Li, Xia

    2016-01-01

    Long intergenic non-coding RNAs (lincRNAs) are emerging as important regulatory molecules involved in diseases including heart failure. However, little is known about how the lincRNAs work together with protein-coding genes (PCGs) contributing to the pathogenesis of heart failure. In this study, we constructed a comprehensive transcriptome profile of lincRNAs, PCGs and miRNAs using RNA-seq and miRNA-seq data of 16 heart failure patients (HFs) and 8 non-failing individuals (NFs). Through integrating lincRNA and PCG expression profiles, we identified HF-associated lincRNA modules. We identified a heart-specific lincRNA module which was significantly enriched for differentially expressed lincRNAs and PCGs. This module was associated with heart failure rather than with other clinical traits such as sex, age, smoking and diabetes mellitus. Moreover, the module was significantly correlated with certain indicators of left ventricular function like ejection fraction and left ventricular end-diastolic diameter, implying the potential of its components as crucial biomarkers. Apart from enhancer-like function, lincRNAs in this module could act as competing endogenous RNAs (ceRNAs) to regulate genes which were associated with left-ventricular systolic function. Our work provided deep insights into the critical roles of lincRNAs in the pathology of heart failure and suggested that they could be valuable biomarkers and therapeutic targets. PMID:28040802

  5. Validity and reliability of the caregiver contribution to self-care of heart failure index.

    PubMed

    Vellone, Ercole; Riegel, Barbara; Cocchieri, Antonello; Barbaranelli, Claudio; D'Agostino, Fabio; Glaser, Dale; Rocco, Gennaro; Alvaro, Rosaria

    2013-01-01

    Caregivers make an important contribution to the self-care of patients with heart failure (HF), but few instruments are available to measure this contribution. The objective of this study was to test the psychometric properties of the Caregiver Contribution to Self-care of Heart Failure Index (CC-SCHFI), an instrument derived from the Self-care of Heart Failure Index version 6.2. The CC-SCHFI measures the contribution of caregivers to the self-care maintenance and self-care management of HF patients, as well as their confidence in their ability to contribute to the patients' HF self-care. A cross-sectional design was used to study 291 Italian caregivers whose HF patients were cared for in 17 cardiovascular centers across Italy. Caregivers completed the CC-SCHFI and a sociodemographic questionnaire. Caregivers were retested on the CC-SCHFI 2 weeks later to assess test-retest reliability. Most caregivers were women (66%) with a mean age of 59 years. First- and second-order confirmatory factor analysis (CFA) for each CC-SCHFI scale showed good model fit: χ2 = 37.22, P = .08, Comparative Fit Index (CFI) = 0.97, Non-Normed Fit Index (NNFI) = 0.96 for caregiver contribution to self-care maintenance (second-order CFA); χ2 = 14.05, P = .12, CFI = 0.96, NNFI = 0.93 for caregiver contribution to self-care management (first-order CFA); and χ2 = 10.63, P = .15, CFI = 0.99, NNFI = 0.98 for caregiver confidence in contributing to self-care (second-order CFA). The CC-SCHFI was able to discriminate statistical and clinical differences between 2 groups of caregivers who had received or not received HF self-care education. Internal consistency reliability measured by factor score determinacy was more than .80 for all factors and scales except for 1 factor in the caregiver contribution to self-care management scale (.65). Test-retest reliability computed by intraclass correlation coefficient was high (>0.90) for most factors and scales. The CC-SCHFI showed good psychometric

  6. Contribution a la comprehension de la durabilite a l'ecaillage des betons contenant de la cendre volante et du laitier

    NASA Astrophysics Data System (ADS)

    Houehanou, Ernesto C.

    significativement leurs resistances a l'ecaillage mais elle a tendance a reduire la durabilite a l'ecaillage des betons contenant de laitier. Pour developper une bonne resistance a l'ecaillage, il est essentiel de produire une surface de beton impermeable qui resiste a la penetration de l'eau externe. La permeabilite et la porosite de la peau du beton sont etroitement liees a la sorptivite. L' allongement de la duree de murissement humide des betons avec ajouts cimentaires diminue systematiquement la sorptivite et ameliore leur durabilite a l'ecaillage, particulierement dans le cas des betons avec cendres volantes. Les resultats montrent qu'il existe une bonne correlation entre les resultats des essais d'ecaillage et les mesures de sorptivite. La correlation etablie entre la sorptivite et la durabilite a l'ecaillage des betons, l'effet • determinant de la carbonatation sur la durabilite a l'ecaillage des betons avec cendres volantes ainsi que l'explication de l'origine de la difference de severite entre les essais ASTM C-672 et NQ 2621-900 sont les contributions scientifiques de cette these. Au plan technique et industriel, elle met en evidence le mode de murissement qui favorise une meilleure durabilite a l'ecaillage des betons et suggere une methode de caracterisation en laboratoire qui ferait une meilleure prediction du comportement en service. Mots cles : Beton, cendre volante, laitier, durabilite, ecaillage, murissement, sorptivite

  7. Quantifying Pilot Contribution to Flight Safety During an In-Flight Airspeed Failure

    NASA Technical Reports Server (NTRS)

    Etherington, Timothy J.; Kramer, Lynda J.; Bailey, Randall E.; Kennedey, Kellie D.

    2017-01-01

    Accident statistics cite the flight crew as a causal factor in over 60% of large transport fatal accidents. Yet a well-trained and well-qualified crew is acknowledged as the critical center point of aircraft systems safety and an integral component of the entire commercial aviation system. A human-in-the-loop test was conducted using a Level D certified Boeing 737-800 simulator to evaluate the pilot's contribution to safety-of-flight during routine air carrier flight operations and in response to system failures. To quantify the human's contribution, crew complement was used as an independent variable in a between-subjects design. This paper details the crew's actions and responses while dealing with an in-flight airspeed failure. Accident statistics often cite flight crew error (Baker, 2001) as the primary contributor in accidents and incidents in transport category aircraft. However, the Air Line Pilots Association (2011) suggests "a well-trained and well-qualified pilot is acknowledged as the critical center point of the aircraft systems safety and an integral safety component of the entire commercial aviation system." This is generally acknowledged but cannot be verified because little or no quantitative data exists on how or how many accidents/incidents are averted by crew actions. Anecdotal evidence suggest crews handle failures on a daily basis and Aviation Safety Action Program data generally supports this assertion, even if the data is not released to the public. However without hard evidence, the contribution and means by which pilots achieve safety of flight is difficult to define. Thus, ways to improve the human ability to contribute or overcome deficiencies are ill-defined.

  8. Contribution à la modélisation des convertisseurs statiques pour la simulation à topologie variable

    NASA Astrophysics Data System (ADS)

    Sahraoui, Omar; Gerbaud, Laurent; Normand, Olivier; Roudet, James

    1993-06-01

    This paper presents a simple and structured method of static converter modelling with variable topology, for the simulation of controlled converter-machine drives. The methodology is based on the notion of switching cells which enables a modular decomposition of converters in structures easy to be studied and henceforth called independent converter legs. These independent legs will be stored in libraries (algorithms or programs, and models) in order to be re-used for the study of other converters. Cet article propose une méthode simple et structurée pour la modélisation des convertisseurs statiques par des modèles à topologie variable, en vue de la simulation d'associations machine-convertisseur-commande complètes. Cette démarche s'appuie sur la notion de cellule de commutation pour permettre de dégager une décomposition modulaire du convertisseur en structures élémentaires, faciles à étudier, qui seront appelées bras indépendants. Ces derniers sont stockés en bibliothèque (sous forme d'algorithme ou programme, et sous forme de modèle), pour être réutilisés dans l'étude d'autres convertisseurs.

  9. Contribution au contrôle de la fluidisation des sédiments marins par ultrasons

    NASA Astrophysics Data System (ADS)

    Bresson, J.; Daïf, A.; Longuemard, J. P.; Mevel, Y.

    1994-08-01

    The authors present an original method based on acoustic propagation of longitudinal waves to determine the state of fluidisation in marine sediments as a function of wave characteristics. Indeed, the pressure variations due to the wave in permeable marine sediments contributes to the desegregation of the inter granular structure. This approach have been tested in wave's channel before being experiment in sea environment. Après avoir présenté le phénomène de fluidisation des sédiments marins et sa modélisation simple, les auteurs étudient dans un canal à houle et expérimentent en mer une méthode, basée sur la propagation d'ondes ultrasonores longitudinales, permettant de détecter l'état de fluidisation du sédiment marin en fonction des caractéristiques de la houle. En effet, les variations de pression engendrées par la houle, dans les sédiments marins perméables, détruisent la liaison du "squelette" inter granulaire existant dans celui-ci quand il est consolidé. Il n'y a plus de contact grain à grain, mais un mince film d'eau sépare complètement ces derniers. On assiste alors à la fluidisation des sédiments près du fond. Cet état est détecté par moyens acoustiques.

  10. Caregivers' contributions to heart failure self-care: a systematic review.

    PubMed

    Buck, Harleah G; Harkness, Karen; Wion, Rachel; Carroll, Sandra L; Cosman, Tammy; Kaasalainen, Sharon; Kryworuchko, Jennifer; McGillion, Michael; O'Keefe-McCarthy, Sheila; Sherifali, Diana; Strachan, Patricia H; Arthur, Heather M

    2015-02-01

    The purpose of this study was to conduct a systematic review answering the following questions: (a) what specific activities do caregivers (CGs) contribute to patients' self-care in heart failure (HF)?; and (b) how mature (or developed) is the science of the CG contribution to self-care? MEDLINE, EMBASE, Cumulative Index of Nursing and Allied Health Literature (CINAHL), the Cochrane Library and ClinicalTrials.gov were searched using the terms heart failure and caregiv* as well as the keywords 'careers', 'family members' and 'lay persons' for studies published between 1948 and September 2012. Inclusion criteria for studies were: informal CGs of adult HF patients-either as dependent/independent variable in quantitative studies or participant in qualitative studies; English language. Exclusion criteria for studies were: formal CGs; pediatric, adult congenital, or devices or transplant CGs; mixed diagnosis; non-empiric reports or reports publishing duplicate results. Each study was abstracted and confirmed by two authors. After CG activities were identified and theoretically categorized, an analysis across studies was conducted. Forty papers were reviewed from a pool of 283 papers. CGs contribute substantively to HF patients' self-care characterized from concrete (weighing the patient) to interpersonal (providing understanding). Only two studies attempted to quantify the impact of CGs' activities on patients' self-care reporting a positive impact. Our analysis provides evidence for a rapidly developing science that is based largely on observational research. To our knowledge, this is the first systematic review to examine CGs' contributions in depth. Informal caregivers play a major role in HF self-care. Longitudinal research is needed to examine the impact of CGs' contributions on patient self-care outcomes. © The European Society of Cardiology 2013.

  11. Does Disruption of Circadian Rhythms Contribute to Beta-Cell Failure in Type 2 Diabetes?

    PubMed Central

    Rakshit, Kuntol; Thomas, Anthony P.

    2014-01-01

    Type 2 diabetes mellitus (T2DM) is a complex metabolic disease characterized by the loss of beta-cell secretory function and mass. The pathophysiology of beta-cell failure in T2DM involves a complex interaction between genetic susceptibilities and environmental risk factors. One environmental condition that is gaining greater appreciation as a risk factor for T2DM is the disruption of circadian rhythms (eg, shift-work and sleep loss). In recent years, circadian disruption has become increasingly prevalent in modern societies and consistently shown to augment T2DM susceptibility (partly mediated through its effects on pancreatic beta-cells). Since beta-cell failure is essential for development of T2DM, we will review current work from epidemiologic, clinical, and animal studies designed to gain insights into the molecular and physiological mechanisms underlying the predisposition to beta-cell failure associated with circadian disruption. Elucidating the role of circadian clocks in regulating beta-cell health will add to our understanding of T2DM pathophysiology and may contribute to the development of novel therapeutic and preventative approaches. PMID:24532160

  12. Direct acute tubular damage contributes to Shigatoxin-mediated kidney failure.

    PubMed

    Porubsky, Stefan; Federico, Giuseppina; Müthing, Johannes; Jennemann, Richard; Gretz, Norbert; Büttner, Stefan; Obermüller, Nicholas; Jung, Oliver; Hauser, Ingeborg A; Gröne, Elisabeth; Geiger, Helmut; Gröne, Hermann-Josef; Betz, Christoph

    2014-09-01

    The pathogenesis and therapy of Shigatoxin 2 (Stx2)-mediated kidney failure remain controversial. Our aim was to test whether, during an infection with Stx2-producing E. coli (STEC), Stx2 exerts direct effects on renal tubular epithelium and thereby possibly contributes to acute renal failure. Mice represent a suitable model because they, like humans, express the Stx2-receptor Gb3 in the tubular epithelium but, in contrast to humans, not in glomerular endothelia, and are thus free of glomerular thrombotic microangiopathy (TMA). In wild-type mice, Stx2 caused acute tubular dysfunction with consequent electrolyte disturbance, which was most likely the cause of death. Tubule-specific depletion of Gb3 protected the mice from acute renal failure. In vitro, Stx2 induced secretion of proinflammatory cytokines and apoptosis in human tubular epithelial cells, thus implicating a direct effect of Stx2 on the tubular epithelium. To correlate these results to human disease, kidney biopsies and outcome were analysed in patients with Stx2-associated kidney failure (n = 11, aged 22-44 years). The majority of kidney biopsies showed different stages of an ongoing TMA; however, no glomerular complement activation could be demonstrated. All biopsies, including those without TMA, showed severe acute tubular damage. Due to these findings, patients were treated with supportive therapy without complement-inhibiting antibodies (eculizumab) or immunoadsorption. Despite the severity of the initial disease [creatinine 6.34 (1.31-17.60) mg/dl, lactate dehydrogenase 1944 (753-2792) U/l, platelets 33 (19-124)/nl and haemoglobin 6.2 (5.2-7.8) g/dl; median (range)], all patients were discharged after 33 (range 19-43) days with no neurological symptoms and no dialysis requirement [creatinine 1.39 (range 0.84-2.86) mg/dl]. The creatinine decreased further to 0.90 (range 0.66-1.27) mg/dl after 24 months. Based on these data, one may surmise that acute tubular damage represents a separate

  13. Direct acute tubular damage contributes to Shigatoxin-mediated kidney failure

    PubMed Central

    Porubsky, Stefan; Federico, Giuseppina; Müthing, Johannes; Jennemann, Richard; Gretz, Norbert; Büttner, Stefan; Obermüller, Nicholas; Jung, Oliver; Hauser, Ingeborg A; Gröne, Elisabeth; Geiger, Helmut; Gröne, Hermann-Josef; Betz, Christoph

    2014-01-01

    The pathogenesis and therapy of Shigatoxin 2 (Stx2)-mediated kidney failure remain controversial. Our aim was to test whether, during an infection with Stx2-producing E. coli (STEC), Stx2 exerts direct effects on renal tubular epithelium and thereby possibly contributes to acute renal failure. Mice represent a suitable model because they, like humans, express the Stx2-receptor Gb3 in the tubular epithelium but, in contrast to humans, not in glomerular endothelia, and are thus free of glomerular thrombotic microangiopathy (TMA). In wild-type mice, Stx2 caused acute tubular dysfunction with consequent electrolyte disturbance, which was most likely the cause of death. Tubule-specific depletion of Gb3 protected the mice from acute renal failure. In vitro, Stx2 induced secretion of proinflammatory cytokines and apoptosis in human tubular epithelial cells, thus implicating a direct effect of Stx2 on the tubular epithelium. To correlate these results to human disease, kidney biopsies and outcome were analysed in patients with Stx2-associated kidney failure (n = 11, aged 22–44 years). The majority of kidney biopsies showed different stages of an ongoing TMA; however, no glomerular complement activation could be demonstrated. All biopsies, including those without TMA, showed severe acute tubular damage. Due to these findings, patients were treated with supportive therapy without complement-inhibiting antibodies (eculizumab) or immunoadsorption. Despite the severity of the initial disease [creatinine 6.34 (1.31–17.60) mg/dl, lactate dehydrogenase 1944 (753–2792) U/l, platelets 33 (19–124)/nl and haemoglobin 6.2 (5.2–7.8) g/dl; median (range)], all patients were discharged after 33 (range 19–43) days with no neurological symptoms and no dialysis requirement [creatinine 1.39 (range 0.84–2.86) mg/dl]. The creatinine decreased further to 0.90 (range 0.66–1.27) mg/dl after 24 months. Based on these data, one may surmise that acute tubular damage represents a

  14. Detection, Diagnosis and Prognosis: Contribution to the energy challenge: Proceedings of the Meeting of the Mechanical Failures Prevention Group

    NASA Astrophysics Data System (ADS)

    Shives, T. R.; Willard, W. A.

    1981-10-01

    The contribution of failure detection, diagnosis and prognosis to the energy challenge is discussed. Areas of special emphasis included energy management, techniques for failure detection in energy related systems, improved prognostic techniques for energy related systems and opportunities for detection, diagnosis and prognosis in the energy field.

  15. Detection, Diagnosis and Prognosis: Contribution to the energy challenge: Proceedings of the Meeting of the Mechanical Failures Prevention Group

    NASA Technical Reports Server (NTRS)

    Shives, T. R. (Editor); Willard, W. A. (Editor)

    1981-01-01

    The contribution of failure detection, diagnosis and prognosis to the energy challenge is discussed. Areas of special emphasis included energy management, techniques for failure detection in energy related systems, improved prognostic techniques for energy related systems and opportunities for detection, diagnosis and prognosis in the energy field.

  16. Metabolic alkalosis contributes to acute hypercapnic respiratory failure in adult cystic fibrosis.

    PubMed

    Holland, Anne E; Wilson, John W; Kotsimbos, Thomas C; Naughton, Matthew T

    2003-08-01

    and study objectives: Patients with end-stage cystic fibrosis (CF) develop respiratory failure and hypercapnia. In contrast to COPD patients, altered electrolyte transport and malnutrition in CF patients may predispose them to metabolic alkalosis and, therefore, may contribute to hypercapnia. The aim of this study was to determine the prevalence of metabolic alkalosis in adults with hypercapnic respiratory failure in the setting of acute exacerbations of CF compared with COPD. Levels of arterial blood gases, plasma electrolytes, and serum albumin from 14 consecutive hypercapnic CF patients who had been admitted to the hospital with a respiratory exacerbation were compared with 49 consecutive hypercapnic patients with exacerbations of COPD. Hypercapnia was defined as a PaCO(2) of > or = 45 mm Hg. Despite similar PaCO(2) values, patients in the CF group were significantly more alkalotic than were those in the COPD group (mean [+/- SD] pH, 7.43 +/- 0.03 vs 7.37 +/- 0.05, respectively; p < 0.01). A mixed respiratory acidosis and metabolic alkalosis was evident in 71% of CF patients and 22% of COPD patients (p < 0.01). The mean concentrations of plasma chloride (95.1 +/- 4.9 vs 99.8 +/- 5.2 mmol/L, respectively; p < 0.01) and sodium (136.5 +/- 2.8 vs 140.4 +/- 4.5 mmol/L, respectively; p < 0.01) were significantly lower in the CF group, and the levels of serum albumin were significantly reduced (27.4 +/- 5.8 vs 33.7 +/- 4.8 mmol/L, respectively; p < 0.01). Metabolic alkalosis contributes to hypercapnic respiratory failure in adults with acute exacerbations of CF. This acid-base disturbance occurs in conjunction with reduced total body salt levels and hypoalbuminemia.

  17. Mechanical failures as a contributing cause to motor vehicle accidents South Africa.

    PubMed

    van Schoor, O; van Niekerk, J L; Grobbelaar, B

    2001-11-01

    Over the past decades motor vehicles became the primary mode of transportation in developing countries. At the same time an improvement in automotive engineering and manufacturing as well as the phenomena of urbanisation have resulted in more vehicles spending more time on the road at higher speeds. Invariably this leads to driving scenarios where safety critical manoeuvres have to be performed that rely on the mechanical condition of the vehicles. In developing countries, where economic realities force the population to make use of older and less reliable vehicles, the risk of accidents caused by some sort of mechanical failure increases. The casualty rate (events causing death and/or serious injuries) for road traffic accidents in South Africa is amongst the highest in the world. This trend has persisted with little variation over the years, despite the efforts of local road safety organisations and research institutes to decrease them. The main goal of this study was to establish the contribution of mechanical failures to motor vehicle accidents, and furthermore, to compare it with international trends. Data obtained from accident response units (ARU) indicate that tyres and brakes were the main contributors to mechanical failures resulting in accidents in the Pretoria region (Gauteng Province). However, the reported percentage of approximately 3% is comparable to similar statistics from developed countries. Detailed information on the condition of road-going vehicles was then collected in this area. The roadside survey (potential mechanical defect tests (PMDT)) indicated that 40% of the vehicles surveyed on the suburban road and 29% of the vehicles surveyed on the highway had mechanical defects that contravened current road and traffic regulations in South Africa and may, therefore, be at risk of causing an accident due to a mechanical failure. In the Minibus (taxi) survey, large irregularities in tyre inflation pressure were identified as a cause of concern

  18. Revue systématique sur la contribution des femmes distributeurs communautaires dans la lutte contre l'onchocercose en Afrique sub-saharienne

    PubMed Central

    Vouking, Marius Zambou; Tadenfok, Carine Nouboudem; Evina, Christine Danielle; Nsangou, Moustapha; Bonono, Cécile-Renée; Yondo, David

    2014-01-01

    Le Programme Africain de lutte contre l'Onchocercose (APOC) fut lancé en 1995, comme complément au brillant programme de lutte contre l'onchocercose en Afrique de l'Ouest. En 2011, plus de 80 millions de personnes ont bénéficié de cette intervention grâce à la contribution de 268 718 Distributeurs Communautaires (DC). Ses résultats significatifs occultent le rôle des femmes DC dans cette lutte cette maladie. L'objectif de cette analyse est de déterminer la contribution des femmes DC dans le traitement de l'onchocercose sous directive communautaire en Afrique sub-saharienne, et d’évaluer leur acceptation dans ledit programme. Comme stratégie de recherche, nous avons identifié toutes les études pertinentes de Janvier 1995 à Décembre 2012. Des recherches ont été effectuées dans les bases de données suivantes: Medline, Embase (Excerpta Medica Database), CINAHL (Cumulative Index to Nursing and Allied Health Literature), LILAS (Latin American and Caribbean Literature on Health Sciences). Nous avons également consulté les sites d'APOC et de l'OMS AFRO. Deux auteurs ont indépendamment évalué la pertinence des articles potentiels à l'aide des critères d'inclusion et d'exclusion bien définis. Six (6) des 25 études ont rempli les critères d'inclusion. Une étude a montré que 81% des populations où il y avait des femmes DC ont reçu l'Ivermectine par rapport à 78% des villages où n'exerçaient pas de femmes DC. Une autre étude a montré qu'il y a eu une prise de conscience croissante dans les IDC en faveur de l'acceptation de la participation des femmes à la distribution communautaire de l'Ivermectine. De plus, 70% des membres de la communauté interrogés dans certaines zones endémiques, ont déclaré que les femmes étaient plus engagées, persuasives et plus patientes que les hommes dans la distribution de l'Ivermectine. Au terme de cette étude, les évaluations qui ont été effectuées donnent à penser que les femmes peuvent jouer

  19. Contribution of peripheral and central chemoreceptors to sympatho-excitation in heart failure.

    PubMed

    Toledo, Camilo; Andrade, David C; Lucero, Claudia; Schultz, Harold D; Marcus, Noah; Retamal, Mauricio; Madrid, Carlos; Del Rio, Rodrigo

    2017-01-01

    Chronic heart failure (CHF) is a major public health problem. Tonic hyper-activation of sympathetic neural outflow is commonly observed in patients with CHF. Importantly, sympatho-excitation in CHF exacerbates its progression and is strongly related to poor prognosis and high mortality risk. Increases in both peripheral and central chemoreflex drive are considered markers of the severity of CHF. The principal peripheral chemoreceptors are the carotid bodies (CBs) and alteration in their function has been described in CHF. Mainly, during CHF the CB chemosensitivity is enhanced leading to increases in ventilation and sympathetic outflow. In addition to peripheral control of breathing, central chemoreceptors (CCs) are considered a dominant mechanism in ventilatory regulation. Potentiation of the ventilatory and sympathetic drive in response to CC activation has been shown in patients with CHF as well as in animal models. Therefore, improving understanding of the contribution of the peripheral and central chemoreflexes to augmented sympathetic discharge in CHF could help in developing new therapeutic approaches intended to attenuate the progression of CHF. Accordingly, the main focus of this review is to discuss recent evidence that peripheral and central chemoreflex function are altered in CHF and that they contribute to autonomic imbalance and progression of CHF.

  20. Contribution of central nervous system endothelial nitric oxide synthase to neurohumoral activation in heart failure rats.

    PubMed

    Biancardi, Vinicia C; Son, Sook J; Sonner, Patrick M; Zheng, Hong; Patel, Kaushik P; Stern, Javier E

    2011-09-01

    Neurohumoral activation, a hallmark in heart failure (HF), is linked to the progression and mortality of HF patients. Thus, elucidating its precise underlying mechanisms is of critical importance. Other than its classic peripheral vasodilatory actions, the gas NO is a pivotal neurotransmitter in the central nervous system control of the circulation. While accumulating evidence supports a contribution of blunted NO function to neurohumoral activation in HF, the precise cellular sources, and NO synthase (NOS) isoforms involved, remain unknown. Here, we used a multidisciplinary approach to study the expression, cellular distribution, and functional relevance of the endothelial NOS isoform within the hypothalamic paraventricular nucleus in sham and HF rats. Our results show high expression of endothelial NOS in the paraventricular nucleus (mostly confined to astroglial cells), which contributes to constitutive NO bioavailability, as well as tonic inhibition of presympathetic neuronal activity and sympathoexcitatory outflow from the paraventricular nucleus. A diminished endothelial NOS expression and endothelial NOS-derived NO availability were found in the paraventricular nucleus of HF rats, resulting, in turn, in blunted NO inhibitory actions on neuronal activity and sympathoexcitatory outflow. Taken together, our study supports blunted central nervous system endothelial NOS-derived NO as a pathophysiological mechanism underlying neurohumoral activation in HF.

  1. Galectin-3 marks activated macrophages in failure-prone hypertrophied hearts and contributes to cardiac dysfunction.

    PubMed

    Sharma, Umesh C; Pokharel, Saraswati; van Brakel, Thomas J; van Berlo, Jop H; Cleutjens, Jack P M; Schroen, Blanche; André, Sabine; Crijns, Harry J G M; Gabius, Hans-J; Maessen, Jos; Pinto, Yigal M

    2004-11-09

    Inflammatory mechanisms have been proposed to be important in heart failure (HF), and cytokines have been implicated to add to the progression of HF. However, it is unclear whether such mechanisms are already activated when hypertrophied hearts still appear well-compensated and whether such early mechanisms contribute to the development of HF. In a comprehensive microarray study, galectin-3 emerged as the most robustly overexpressed gene in failing versus functionally compensated hearts from homozygous transgenic TGRmRen2-27 (Ren-2) rats. Myocardial biopsies obtained at an early stage of hypertrophy before apparent HF showed that expression of galectin-3 was increased specifically in the rats that later rapidly developed HF. Galectin-3 colocalized with activated myocardial macrophages. We found galectin-3-binding sites in rat cardiac fibroblasts and the extracellular matrix. Recombinant galectin-3 induced cardiac fibroblast proliferation, collagen production, and cyclin D1 expression. A 4-week continuous infusion of low-dose galectin-3 into the pericardial sac of healthy Sprague-Dawley rats led to left ventricular dysfunction, with a 3-fold differential increase of collagen I over collagen III. Myocardial galectin-3 expression was increased in aortic stenosis patients with depressed ejection fraction. This study shows that an early increase in galectin-3 expression identifies failure-prone hypertrophied hearts. Galectin-3, a macrophage-derived mediator, induces cardiac fibroblast proliferation, collagen deposition, and ventricular dysfunction. This implies that HF therapy aimed at inflammatory responses may need to be targeted at the early stages of HF and probably needs to antagonize multiple inflammatory mediators, including galectin-3.

  2. Review of Fusion Systems and Contributing Technologies for SIHS-TD (Examen des Systemes de Fusion et des Technologies d’Appui pour la DT SIHS)

    DTIC Science & Technology

    2007-03-31

    de la DT - SIHS. L’équipe des sous-systèmes de vision de la DT - SIHS planifie le développement à court terme d’un banc d’essai de fusion...references, the researcher systematically added additional keywords to refine the search. In general, this process produced many irrelevant references...development. State of the art fusion processing system architectures are described. The report analyses selected fusion systems based on their ability to

  3. Calcium/Calmodulin-Dependent Protein Kinase II Contributes to Cardiac Arrhythmogenesis in Heart Failure

    PubMed Central

    Sag, Can M.; Wadsack, Daniel P.; Khabbazzadeh, Sepideh; Abesser, Marco; Grefe, Clemens; Neumann, Kay; Opiela, Marie-Kristin; Backs, Johannes; Olson, Eric N.; Brown, Joan Heller; Neef, Stefan; Maier, Sebastian K.G.; Maier, Lars S.

    2010-01-01

    Background Transgenic (TG) Ca/calmodulin-dependent protein kinase II (CaMKII)δC mice have heart failure and isoproterenol (ISO)-inducible arrhythmias. We hypothesized that CaMKII contributes to arrhythmias and underlying cellular events and that inhibition of CaMKII reduces cardiac arrhythmogenesis in vitro and in vivo. Methods and Results Under baseline conditions, isolated cardiac myocytes from TG mice showed an increased incidence of early afterdepolarizations compared with wild-type myocytes (P<0.05). CaMKII inhibition (AIP) completely abolished these afterdepolarizations in TG cells (P<0.05). Increasing intracellular Ca stores using ISO (10−8 M) induced a larger amount of delayed afterdepolarizations and spontaneous action potentials in TG compared with wild-type cells (P<0.05). This seems to be due to an increased sarcoplasmic reticulum (SR) Ca leak because diastolic [Ca]i rose clearly on ISO in TG but not in wild-type cells (+20±5% versus +3±4% at 10−6 M ISO, P<0.05). In parallel, SR Ca leak assessed by spontaneous SR Ca release events showed an increased Ca spark frequency (3.9±0.5 versus 2.0±0.4 sparks per 100 μm−1·s−1, P<0.05). However, CaMKII inhibition (either pharmacologically using KN-93 or genetically using an isoform-specific CaMKIIδ-knockout mouse model) significantly reduced SR Ca spark frequency, although this rather increased SR Ca content. In parallel, ISO increased the incidence of early (54% versus 4%, P<0.05) and late (86% versus 43%, P<0.05) nonstimulated events in TG versus wild-type myocytes, but CaMKII inhibition (KN-93 and KO) reduced these proarrhythmogenic events (P<0.05). In addition, CaMKII inhibition in TG mice (KN-93) clearly reduced ISO-induced arrhythmias in vivo (P<0.05). Conclusions We conclude that CaMKII contributes to cardiac arrhythmogenesis in TG CaMKIIδC mice having heart failure and suggest the increased SR Ca leak as an important mechanism. Moreover, CaMKII inhibition reduces cardiac arrhythmias in

  4. La contribution des astronomes aux mesures de précision.

    NASA Astrophysics Data System (ADS)

    Debarbat, S.

    The system for astronomical constants includes the astronomical unit, the velocity of light and the light-time for the unit distance in the metric system. In France, at least from the 17th century, scientists had in mind to unify the units. But it is not before the time of the French Revolution that it was succeeded to adopt a unified system based on the metre. Measurements were made of an arc of meridian, from Dunkirk to Barcelona to determine the new unit as the fraction of 1 over 107 of a quarter of any part of the Earth from the north pole to the equator. On the occasion of the bicentenary of the nomenclature of the metric system (1795), the Paris Observatory has presented during more than six months in 1995, mostly for students, manuscripts, documents related to the subject, in its galeries on the first floor of the Perrault building. The exhibition ended with the 1960 and 1983 definitions of the meter to which the Paris Observatory has contributed. For astronomers it was recalled the reason for which the Angström had to be considered as not more usable, being only close to the fraction 1/1010 of the meter.

  5. ASIC3 Contributes to the Blunted Muscle Metaboreflex in Heart Failure

    PubMed Central

    Xing, Jihong; Lu, Jian; Li, Jianhua

    2014-01-01

    Introduction During exercise, the sympathetic nervous system is activated and blood pressure and heart rate increase. In heart failure (HF), the muscle metaboreceptor contribution to sympathetic outflow is attenuated and the mechanoreceptor contribution is accentuated. Previous studies suggest that lactic acid stimulates acid sensing channel subtype 3 (ASIC3), inducing a neurally mediated pressor response. Thus, we hypothesized that the pressor response to ASIC3 stimulation is smaller in HF rats due to attenuation in expression and function of ASIC3 in sensory nerves. Methods Lactic acid was injected into the arterial blood supply of the hindlimb to stimulate ASIC3 in muscle afferent nerves and evoke the muscle metaboreceptor response in control rats and HF rats. Also, western blot analysis was employed to examine expression of ASIC3 in dorsal root ganglion (DRG) and patch clamp to examine current response with ASIC3 activation. Results Lactic acid (4 µmol/kg) increased mean arterial pressure by 28±5 mmHg in controls (n=6) but only by 16±3 mmHg (P<0.05 vs. control) in HF (n=8). In addition, HF decreased the protein levels of ASIC3 in DRG (optical density: 1.03±0.02 in control vs. 0.79±0.03 in HF, P<0.05; n=6 in each group). The peak current amplitude of dorsal DRG neuron in response to ASIC3 stimulation is smaller in HF rats than that in control rats. Conclusions Compared with controls, cardiovascular responses to lactic acid administered into the hindlimb muscles are blunted in HF rats owing to attenuated ASIC3. This suggests that ASIC3 plays a role in engagement in the attenuated metaboreceptor component of the exercise pressor reflex in HF. PMID:24983337

  6. The contribution of observational studies to the knowledge of drug effectiveness in heart failure

    PubMed Central

    Dobre, Daniela; van Veldhuisen, Dirk J; deJongste, Mike J L; van Sonderen, Eric; Klungel, Olaf H; Sanderman, Robbert; Ranchor, Adelita V; Haaijer-Ruskamp, Flora M

    2007-01-01

    Aims Randomized controlled trials (RCTs) are the golden standard for the assessment of drug efficacy. Little is known about the add-on value of observational studies in heart failure (HF). We aimed to assess the contribution of observational studies to actual knowledge regarding the effectiveness of angiotensin-converting enzyme inhibitors (ACEI), and β-blockers (BB) in HF. Methods Observational studies that assessed the effectiveness of ACEI and BB in HF were identified by searching Medline, Embase, Cochrane Database (1990–2005) and the bibliographies of published articles. Cohort, case–control and time-series analysis studies were considered for inclusion. Studies with <100 patients and those who did not perform a multivariate analysis were excluded. Results A total of 23 cohort studies met the inclusion criteria. Studies of ACEI and BB showed a decrease in mortality with drug use in elderly patients with a broad range of ejection fraction (EF), and in those with depressed EF. Additionally, they showed a decrease in mortality in patients with renal insufficiency. The effect of ACEI and BB in HF with preserved EF was not clear, although last evidence suggests a potential benefit. Low-dose ACEI and BB may have beneficial effects. Target doses of ACEI seemed superior to low doses, but there was no clear dose–response relationship. Conclusions Observational studies in HF validate the effectiveness of ACEI and BB in populations underrepresented or excluded from RCTs. Observational studies of drug effectiveness provide relevant additional information for clinical practice. PMID:17764473

  7. Contributions of clinical disconnections and unresolved conflict to failures in intrapartum safety

    PubMed Central

    Lyndon, Audrey; Zlatnik, Marya G.; Maxfield, David G.; Lewis, Annie; McMillan, Chase; Kennedy, Holly Powell

    2014-01-01

    Objective To explore clinician perspectives on whether they experience difficulty resolving patient-related concerns or observe problems with the performance or behavior of colleagues involved in intrapartum care. Design Qualitative descriptive study of physician, nursing, and midwifery professional association members. Participants and Setting Participants (N=1932) were drawn from the membership lists of the Association of Women’s Health, Obstetric, and Neonatal Nurses (AWHONN), American College of Obstetricians and Gynecologists (ACOG), American College of Nurse Midwives (ACNM), and Society for Maternal-Fetal Medicine (SMFM). Methods Email survey with multiple choice and free text responses. Descriptive statistics and inductive thematic analysis were used to characterize the data. Results Forty-seven percent of participants reported experiencing situations in which patients were put at risk due to failure of team members to listen or respond to a concern. Thirty-seven percent reported unresolved concerns regarding another clinician’s performance. The overarching theme was clinical disconnection, which included disconnections between clinicians about patient needs and plans of care and disconnections between clinicians and administration about the support required to provide safe and appropriate clinical care. Lack of responsiveness to concerns by colleagues and administration contributed to resignation and defeatism among participants who had experienced such situations. Conclusion Despite encouraging progress in developing cultures of safety in individual centers and systems, significant work is needed to improve collaboration and reverse historic normalization of both systemic disrespect and overt disruptive behaviors in intrapartum care. PMID:24354506

  8. Altered systemic bile acid homeostasis contributes to liver disease in pediatric patients with intestinal failure

    PubMed Central

    Xiao, Yong-Tao; Cao, Yi; Zhou, Ke-Jun; Lu, Li-Na; Cai, Wei

    2016-01-01

    Intestinal failure (IF)-associated liver disease (IFALD), as a major complication, contributes to significant morbidity in pediatric IF patients. However, the pathogenesis of IFALD is still uncertain. We here investigate the roles of bile acid (BA) dysmetabolism in the unclear pathogenesis of IFALD. It found that the histological evidence of pediatric IF patients exhibited liver injury, which was characterized by liver bile duct proliferation, inflammatory infiltration, hepatocyte apoptosis and different stages of fibrosis. The BA compositions were altered in serum and liver of pediatric IF patients, as reflected by a primary BA dominant composition. In IF patients, the serum FGF19 levels decreased significantly, and were conversely correlated with ileal inflammation grades (r = −0.50, p < 0.05). In ileum, the inflammation grades were inversely associated with farnesoid X receptor (FXR) expression (r = −0.55, p < 0.05). In liver, the expression of induction of the rate-limiting enzyme in bile salt synthesis, cytochrome P450 7a1 (CYP7A1) increased evidently. In conclusion, ileum inflammation decreases FXR expression corresponding to reduce serum FGF19 concentration, along with increased hepatic bile acid synthesis, leading to liver damages in IF patients. PMID:27976737

  9. High-Output Heart Failure Contributing to Recurrent Epistaxis Kiesselbach Area Syndrome in a Patient With Hereditary Hemorrhagic Telangiectasia

    PubMed Central

    Bhattad, Venugopal Brijmohan; Bowman, Jennifer N.; Panchal, Hemang B.; Paul, Timir K.

    2017-01-01

    Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare genetic blood disorder that leads to abnormal bleeding due to absent capillaries and multiple abnormal blood vessels known as arteriovenous malformations. A feature of HHT is high-output heart failure due to multiple arteriovenous malformations. High-output heart failure can lead to recurrent epistaxis Kiesselbach area syndrome (REKAS), further exacerbating heart failure through increased blood loss and resultant anemia. We report a patient with HHT who presented with high-output heart failure contributing to REKAS. In patients with REKAS, we propose if anemia is present, REKAS can be avoided by correcting the anemia by increasing the hemoglobin level to greater than 9 to 10 g/dL. This decreases hyperdynamic circulation and reduces pressure in the blood vessels of the nose. PMID:28210642

  10. Contribution of ischemic mitral regurgitation to congestive heart failure after myocardial infarction.

    PubMed

    Grigioni, Francesco; Detaint, Delphine; Avierinos, Jean-François; Scott, Christopher; Tajik, Jamil; Enriquez-Sarano, Maurice

    2005-01-18

    The purpose of this study was to define the contribution of ischemic mitral regurgitation (IMR) to the occurrence of congestive heart failure (CHF) after myocardial infarction (MI). After MI, CHF is a frequent and serious complication, but its determinants and, particularly, the role of IMR are poorly defined. We analyzed 173 asymptomatic patients with previous Q-wave MI (>16 days) with echocardiographic quantitation of IMR (measuring effective regurgitant orifice [ERO] and regurgitant volume). The 102 patients with IMR were matched to 71 patients without IMR for age (71 +/- 11 years vs. 68 +/- 9 years; p = 0.11), gender (76% vs. 82% males; p = 0.41), and left ventricular ejection fraction (EF) (37 +/- 14% vs. 36 +/- 11%; p = 0.92). Five-year rates of CHF and of CHF or cardiac death (CD) were 36 +/- 5% and 52 +/- 5%, respectively. Independent determinants of CHF were EF, sodium plasma level, and presence and degree of IMR (p < 0.0001). Five-year CHF rates were 18 +/- 5% without mitral regurgitation (MR), 53 +/- 7% with IMR, 46 +/- 9% with ERO 1 to 19 mm(2) and 68 +/- 12% with ERO > or =20 mm(2) (all p < 0.0001). The adjusted relative risk of CHF was 3.65 (95% confidence interval [CI] 1.86 to 7.75) for IMR presence and 4.42 (95% CI 1.9 to 10.5) for ERO > or =20 mm(2). The adjusted relative risk of CHF/CD was 2.97 (95% CI 1.77 to 5.16) for IMR presence and 4.4 (95% CI 2.4 to 8.2) for ERO > or =20 mm(2). After MI, incidence of CHF and of CHF/CD are high even in patients with no or minimal symptoms at baseline and are higher in patients with IMR. Congestive heart failure is independently determined by larger ERO of IMR. These data suggest that detecting and quantifying IMR is essential for risk stratification after MI. Value of IMR treatment in improving post-MI outcome should be investigated.

  11. Don’t get (sun) burned : exposing exterior wood to the weather prior to painting contributes to finish failure

    Treesearch

    R. Sam Williams

    2005-01-01

    Contrary to what might be called popular myth, research shows that allowing exterior wood surfaces to weather before applying paint does not help the cause of long-term coating performance. Instead, weathering prior to painting has been shown to contribute significantly to premature failure of the finish due to loss of adhesion.

  12. Impaired Myocardial Oxygen Availability Contributes to Abnormal Exercise Hemodynamics in Heart Failure With Preserved Ejection Fraction

    PubMed Central

    van Empel, Vanessa P. M.; Mariani, Justin; Borlaug, Barry A.; Kaye, David M.

    2014-01-01

    Background Hypertension is a frequent risk factor for the development of heart failure with preserved ejection fraction (HFPEF). Progressive extracellular matrix accumulation has been presumed to be the fundamental pathophysiologic mechanism that leads to the transition to impaired diastolic reserve. However, the contribution of other mechanisms affecting active and passive components of diastolic function has not been comprehensively assessed. In this study, we investigated the potential role of impaired myocardial oxygen delivery in the pathophysiology of HFPEF. Methods and Results Patients with HFPEF, those with controlled hypertension, and healthy controls underwent simultaneous right‐heart catheterization, echocardiography, and paired arterial and coronary sinus blood gas sampling at rest and during supine‐cycle ergometry. Despite a lower workload (HFPEF vs control, hypertension: 43±8 versus 114±12, 87±14 W; P<0.001 and P<0.05, respectively), peak exercise pulmonary capillary wedge pressure was markedly higher in HFPEF patients compared with healthy and hypertensive controls (32±2 versus 16±1 and 17±1 mm Hg, both P<0.001). During exercise, the transcardiac oxygen gradient increased significantly in all groups; however, the peak transcardiac oxygen gradient was significantly lower in HFPEF patients (P<0.05). In addition, the left ventricular–work corrected transcardiac oxygen gradient remained significantly lower in HFPEF patients compared with controls (P<0.001). Conclusion The current study provides unique data suggesting that the abnormal diastolic reserve observed during exertion in HFPEF patients may, in part, be explained by impaired myocardial oxygen delivery due possibly to microvascular dysfunction. Further studies are required to confirm the structural and functional basis of these findings and to investigate the influence of potential therapies on this abnormality. PMID:25468660

  13. Redox modification of ryanodine receptors contributes to sarcoplasmic reticulum Ca2+ leak in chronic heart failure.

    PubMed

    Terentyev, Dmitry; Györke, Inna; Belevych, Andriy E; Terentyeva, Radmila; Sridhar, Arun; Nishijima, Yoshinori; de Blanco, Esperanza Carcache; Khanna, Savita; Sen, Chandan K; Cardounel, Arturo J; Carnes, Cynthia A; Györke, Sandor

    2008-12-05

    Abnormal cardiac ryanodine receptor (RyR2) function is recognized as an important factor in the pathogenesis of heart failure (HF). However, the specific molecular causes underlying RyR2 defects in HF remain poorly understood. In the present study, we used a canine model of chronic HF to test the hypothesis that the HF-related alterations in RyR2 function are caused by posttranslational modification by reactive oxygen species generated in the failing heart. Experimental approaches included imaging of cytosolic ([Ca(2+)](c)) and sarcoplasmic reticulum (SR) luminal Ca(2+) ([Ca(2+)]SR) in isolated intact and permeabilized ventricular myocytes and single RyR2 channel recording using the planar lipid bilayer technique. The ratio of reduced to oxidized glutathione, as well as the level of free thiols on RyR2 decreased markedly in failing versus control hearts consistent with increased oxidative stress in HF. RyR2-mediated SR Ca(2+) leak was significantly enhanced in permeabilized myocytes, resulting in reduced [Ca(2+)](SR) in HF compared to control cells. Both SR Ca(2+) leak and [Ca(2+)](SR) were partially normalized by treating HF myocytes with reducing agents. Conversely, oxidizing agents accelerated SR Ca(2+) leak and decreased [Ca(2+)](SR) in cells from normal hearts. Moreover, exposure to antioxidants significantly improved intracellular Ca(2+)-handling parameters in intact HF myocytes. Single RyR2 channel activity was significantly higher in HF versus control because of increased sensitivity to activation by luminal Ca(2+) and was partially normalized by reducing agents through restoring luminal Ca(2+) sensitivity oxidation of control RyR2s enhanced their luminal Ca(2+) sensitivity, thus reproducing the HF phenotype. These findings suggest that redox modification contributes to abnormal function of RyR2s in HF, presenting a potential therapeutic target for treating HF.

  14. Sulfonylurea receptor 1 contributes to the astrocyte swelling and brain edema in acute liver failure.

    PubMed

    Jayakumar, A R; Valdes, V; Tong, X Y; Shamaladevi, N; Gonzalez, W; Norenberg, M D

    2014-02-01

    Astrocyte swelling (cytotoxic brain edema) is the major neurological complication of acute liver failure (ALF), a condition in which ammonia has been strongly implicated in its etiology. Ion channels and transporters are known to be involved in cell volume regulation, and a disturbance in these systems may result in cell swelling. One ion channel known to contribute to astrocyte swelling/brain edema in other neurological disorders is the ATP-dependent, nonselective cation (NCCa-ATP) channel. We therefore examined its potential role in the astrocyte swelling/brain edema associated with ALF. Cultured astrocytes treated with 5 mM ammonia showed a threefold increase in the sulfonylurea receptor type 1 (SUR1) protein expression, a marker of NCCa-ATP channel activity. Blocking SUR1 with glibenclamide significantly reduced the ammonia-induced cell swelling in cultured astrocytes. Additionally, overexpression of SUR1 in ammonia-treated cultured astrocytes was significantly reduced by cotreatment of cells with BAY 11-7082, an inhibitor of NF-κB, indicating the involvement of an NF-κB-mediated SUR1 upregulation in the mechanism of ammonia-induced astrocyte swelling. Brain SUR1 mRNA level was also found to be increased in the thioacetamide (TAA) rat model of ALF. Additionally, we found a significant increase in SUR1 protein expression in rat brain cortical astrocytes in TAA-treated rats. Treatment with glibenclamide significantly reduced the brain edema in this model of ALF. These findings strongly suggest the involvement of NCCa-ATP channel in the astrocyte swelling/brain edema in ALF and that targeting this channel may represent a useful approach for the treatment of the brain edema associated with ALF.

  15. Contribution a la modelisation et a l'identification des machines synchrones soumises a la saturation magnetique

    NASA Astrophysics Data System (ADS)

    Tahan, Souheil-Antoine

    Le concept de circuits équivalents, utilisé pour décrire le comportement dynamique des machines électriques, semble établir un large consensus auprès des chercheurs et des industriels. Sa flexibilité et sa capacité de simuler, avec une bonne précision, le comportement de la machine, lui assure un champ d'application certain. Pourtant, si le problème de la modélisation et de l'identification d'une machine tenant compte d'une approche linéaire, semble être résolu depuis quelques années, les chercheurs s'accordent sur le fait que pour améliorer la capacité de prédiction du modèle, il est impératif d'y incorporer les effets non linéaires dus à la saturation magnétique. À partir des équations fondamentales de la physique, nous développons un modèle original pour inclure l'influence de la saturation magnétique sur le comportement dynamique des machines. Plus spécifiquement, nos travaux visent l'incorporation des effets engendrés par la saturation dans des modèles de circuits équivalents déjà reconnus pour leur efficience et leur flexibilité dans le cadre des approches linéaires de modélisation. En conformité avec une démarche scientifique classique, nous présentons une analyse théorique détaillée qui prouve l'existence et explique le comportement des flux dits ``croisés''. Par la suite, et en s'accordant avec les conclusions obtenues, nous appliquons la théorie de Park afin d'obtenir le modèle de la machine exprimé par deux circuits électriques. L'ordre optimal de ce système est maintenu arbitraire en modifiant le nombre d'amortisseurs dans chaque axe. Cette démarche procure au système la flexibilité nécessaire pour caractériser le comportement dynamique d'une multitude de machines. L'application d'une transformée originale nous permet d'introduire l'effet de la saturation dans la partie magnétisante des circuits. Il en résulte un nouveau modèle non linéaire de la machine. Concrètement, notre recherche d

  16. Glutamatergic receptor dysfunction in spinal cord contributes to the exaggerated exercise pressor reflex in heart failure

    PubMed Central

    Wang, Han-Jun; Cahoon, Rebecca; Cahoon, Edgar B.; Zheng, Hong; Patel, Kaushik P.

    2014-01-01

    Excitatory amino acids (e.g., glutamate) released by contraction-activated skeletal muscle afferents into the dorsal horn of the spinal cord initiate the central component of the exercise pressor reflex (EPR) in physiological conditions. However, the role of glutamate and glutamate receptors in mediating the exaggerated EPR in the chronic heart failure (CHF) state remains to be determined. In the present study, we performed microinjection of glutamate receptor antagonists into ipisilateral L4/L5 dorsal horns to investigate their effects on the pressor response to static contraction induced by stimulation of the peripheral end of L4/L5 ventral roots in decerebrate sham-operated (sham) and CHF rats. Microinjection of glutamate (10 mM, 100 nl) into the L4 or L5 dorsal horn caused a greater pressor response in CHF rats compared with sham rats. Furthermore, microinjection of either the broad-spectrum glutamate receptor antagonist kynurenate (10 mM, 100 nl) or the N-methyl-d-aspartate (NMDA) receptor antagonist dl-2-amino-5-phosphonovalerate (50 mM, 100 nl) or the non-NMDA-sensitive receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (5 mM, 100 nl) into L4/5 dorsal horns decreased the pressor response to static contraction in CHF rats to a greater extent than in sham rats. Molecular evidence showed that the protein expression of glutamate receptors (both non-NMDA and NMDA) was elevated in the dorsal horn of the lumbar spinal cord in CHF rats. In addition, data from microdialysis experiments demonstrated that although basal glutamate release at the dorsal horn at rest was similar between sham and CHF rats (225 ± 50 vs. 260 ± 63 nM in sham vs. CHF rats, n = 4, P > 0.05), CHF rats exhibit greater glutamate release into the dorsal horn during muscle contraction compared with sham rats (549 ± 60 vs. 980 ± 65 nM in sham vs. CHF rats, n = 4, P < 0.01). These data indicate that the spinal glutamate system contributes to the exaggerated EPR in the CHF state. PMID

  17. Biological factors contributing to failures of osseointegrated oral implants. (I). Success criteria and epidemiology.

    PubMed

    Esposito, M; Hirsch, J M; Lekholm, U; Thomsen, P

    1998-02-01

    The aim of this review was to offer a critical evaluation of the literature and to provide the clinician with scientifically-based diagnostic criteria for monitoring the implant condition. The review presents the current opinions on definitions of osseointegration and implant failure. Further, distinctions between failed and failing implants are discussed together with the presently used parameters to assess the implant status. Radiographic examinations together with implant mobility tests seem to be the most reliable parameters in the assessment of the prognosis for osseointegrated implants. On the basis of 73 published articles, the rates of early and late failures of Brånemark implants, used in various anatomical locations and clinical situations, were analyzed using a metanalytic approach. Biologically related implant failures calculated on a sample of 2,812 implants were relatively rare: 7.7% over a 5-year period (bone graft excluded). The predictability of implant treatment was remarkable, particularly for partially edentulous patients, who showed failure rates about half those of totally edentulous subjects. Our analysis also confirmed (for both early and late failures) the general trend of maxillas, having almost 3 times more implant losses than mandibles, with the exception of the partially edentulous situation which displayed similar failure rates both in upper and lower jaws. Surgical trauma together with anatomical conditions are believed to be the most important etiological factors for early implant losses (3.60% of 16,935 implants). The low prevalence of failures attributable to peri-implantitis found in the literature together with the fact that, in general, partially edentulous patients have less resorbed jaws, speak in favour of jaw volume, bone quality, and overload as the three major determinants for late implant failures in the Brånemark system. Conversely, the ITI system seemed to be characterized by a higher prevalence of losses due to peri

  18. Contribution of thermal stresses to the failure of Kevlar fabric composites

    SciTech Connect

    Deteresa, S.J.; Nicolais, L.

    1988-06-01

    The effect of temperature changes on the compressive characteristics of Kevlar 49-epoxy composites were investigated. Using published data on the elastic properties of Kevlar 49 fiber and a typical epoxy matrix and the equation for the thermal expansion coefficient (TEC) developed by Schapery (1968) and Nairn (1985) for isotropic and transversely isotropic fibers, respectively, the temperature change required to cause compressive failure of the fiber was calculated for various volume fractions; it was found that, for typical unidirectional composites, thermally induced compressive failure of Kevlar fibers is of little concern. However, a temperature reduction places the curved fiber in the fabric-reinforced composite in axial compression, adding to the bending strain in the fiber. The combination of thermal stresses and external compressive loads that are below ultimate values by themselves can cause local compresive failure of the fiber. In addition, the kink bands formed as a result of compressive failure of Kevlar fiber are expected to cause debonding between fiber and matrix, and thus are also potential sites for crack initiation. 14 references.

  19. Does Fusarium-caused seed mortality contribute to Bromus tectorum stand failure in the Great Basin?

    Treesearch

    S. E. Meyer; J.-L. Franke; O. W. Baughman; J. Beckstead; B. Geary

    2014-01-01

    Bromus tectorum (cheatgrass, downy brome) is an important invader in western North America, dominating millions of hectares of former semi-arid shrubland. Stand failure or 'die-off' is relatively common in monocultures of this annual grass. The study reported here investigated whether soil-borne pathogens could be causal agents in die-offs. Soils from two die...

  20. Proliferation and recruitment contribute to myocardial macrophage expansion in chronic heart failure

    PubMed Central

    Sager, Hendrik B.; Hulsmans, Maarten; Lavine, Kory J.; Moreira, Marina B.; Heidt, Timo; Courties, Gabriel; Sun, Yuan; Iwamoto, Yoshiko; Tricot, Benoit; Khan, Omar F.; Dahlman, James E.; Borodovsky, Anna; Fitzgerald, Kevin; Anderson, Daniel G.; Weissleder, Ralph; Libby, Peter; Swirski, Filip K.; Nahrendorf, Matthias

    2017-01-01

    Rationale Macrophages reside in the healthy myocardium, participate in ischemic heart disease and modulate myocardial infarction (MI) healing. Their origin and roles in post-MI remodeling of non-ischemic remote myocardium, however, remain unclear. Objective This study investigated the number, origin, phenotype and function of remote cardiac macrophages residing in the non-ischemic myocardium in mice with chronic heart failure after coronary ligation. Methods and Results Eight weeks post-MI, fate mapping and flow cytometry revealed that a 2.9-fold increase in remote macrophages results from both increased local macrophage proliferation and monocyte recruitment. Heart failure produced by extensive MI, through activation of the sympathetic nervous system, expanded medullary and extramedullary hematopoiesis. Circulating Ly6Chigh monocytes rose from 64±5 to 108±9 /μl blood (p<0.05). Cardiac monocyte recruitment declined in Ccr2−/− mice, reducing macrophage numbers in the failing myocardium. Mechanical strain of primary murine and human macrophage cultures promoted cell cycle entry, suggesting that the increased wall tension in post-MI heart failure stimulates local macrophage proliferation. Strained cells activated the MAPK pathway, while specific inhibitors of this pathway reduced macrophage proliferation in strained cell cultures and in the failing myocardium (p<0.05). Steady-state cardiac macrophages, monocyte-derived and locally sourced macrophages isolated from failing myocardium expressed different genes in a pattern distinct from the M1/M2 macrophage polarization paradigm. In vivo silencing of endothelial cell adhesion molecules curbed post-MI monocyte recruitment to the remote myocardium and preserved ejection fraction (27.4±2.4 vs.19.1±2%, p<0.05). Conclusions Myocardial failure is influenced by an altered myeloid cell repertoire. PMID:27444755

  1. Proliferation and Recruitment Contribute to Myocardial Macrophage Expansion in Chronic Heart Failure.

    PubMed

    Sager, Hendrik B; Hulsmans, Maarten; Lavine, Kory J; Moreira, Marina B; Heidt, Timo; Courties, Gabriel; Sun, Yuan; Iwamoto, Yoshiko; Tricot, Benoit; Khan, Omar F; Dahlman, James E; Borodovsky, Anna; Fitzgerald, Kevin; Anderson, Daniel G; Weissleder, Ralph; Libby, Peter; Swirski, Filip K; Nahrendorf, Matthias

    2016-09-16

    Macrophages reside in the healthy myocardium, participate in ischemic heart disease, and modulate myocardial infarction (MI) healing. Their origin and roles in post-MI remodeling of nonischemic remote myocardium, however, remain unclear. This study investigated the number, origin, phenotype, and function of remote cardiac macrophages residing in the nonischemic myocardium in mice with chronic heart failure after coronary ligation. Eight weeks post MI, fate mapping and flow cytometry revealed that a 2.9-fold increase in remote macrophages results from both increased local macrophage proliferation and monocyte recruitment. Heart failure produced by extensive MI, through activation of the sympathetic nervous system, expanded medullary and extramedullary hematopoiesis. Circulating Ly6C(high) monocytes rose from 64±5 to 108±9 per microliter of blood (P<0.05). Cardiac monocyte recruitment declined in Ccr2(-/-) mice, reducing macrophage numbers in the failing myocardium. Mechanical strain of primary murine and human macrophage cultures promoted cell cycle entry, suggesting that the increased wall tension in post-MI heart failure stimulates local macrophage proliferation. Strained cells activated the mitogen-activated protein kinase pathway, whereas specific inhibitors of this pathway reduced macrophage proliferation in strained cell cultures and in the failing myocardium (P<0.05). Steady-state cardiac macrophages, monocyte-derived macrophages, and locally sourced macrophages isolated from failing myocardium expressed different genes in a pattern distinct from the M1/M2 macrophage polarization paradigm. In vivo silencing of endothelial cell adhesion molecules curbed post-MI monocyte recruitment to the remote myocardium and preserved ejection fraction (27.4±2.4 versus 19.1±2%; P<0.05). Myocardial failure is influenced by an altered myeloid cell repertoire. © 2016 American Heart Association, Inc.

  2. Autotoxic Ginsenosides in the Rhizosphere Contribute to the Replant Failure of Panax notoginseng

    PubMed Central

    Yang, Min; Zhang, Xiaodan; Xu, Yanguo; Mei, Xinyue; Jiang, Bingbing; Liao, Jingjing; Yin, Zhaobo; Zheng, Jianfen; Zhao, Zhi; Fan, Liming; He, Xiahong; Zhu, Youyong; Zhu, Shusheng

    2015-01-01

    Background and Aims Sanqi ginseng (Panax notoginseng) growth is often hampered by replant failure. In this study, we aimed to examine the role of autotoxicity in Sanqi replant failures and assess the role of ginsenosides in autotoxicity. Methods The autotoxicities were measured using seedling emergence bioassays and root cell vigor staining. The ginsenosides in the roots, soils, and root exudates were identified with HPLC-MS. Results The seedling emergence and survival rate decreased significantly with the continuous number of planting years from one to three years. The root exudates, root extracts, and extracts from consecutively cultivated soils also showed significant autotoxicity against seedling emergence and growth. Ginsenosides, including R1, Rg1, Re, Rb1, Rb3, Rg2, and Rd, were identified in the roots and consecutively cultivated soil. The ginsenosides, Rg1, Re, Rg2, and Rd, were identified in the root exudates. Furthermore, the ginsenosides, R1, Rg1, Re, Rg2, and Rd, caused autotoxicity against seedling emergence and growth and root cell vigor at a concentration of 1.0 µg/mL. Conclusion Our results demonstrated that autotoxicity results in replant failure of Sanqi ginseng. While Sanqi ginseng consecutively cultivated, some ginsenosides can accumulate in rhizosphere soils through root exudates or root decomposition, which impedes seedling emergence and growth. PMID:25695831

  3. Design and Environmental Factors Contributing to the Failure of Thermal Barrier Coating Systems

    NASA Astrophysics Data System (ADS)

    Weeks, Matthew David

    Gas turbine engines are a staple of 21st century air and sea propulsion systems and are also a critical component in large-scale electricity generation. The hot-section components of these engines are protected by a complex ceramic and metal multi-layer coating called a thermal barrier coating (TBC) system. The failure of TBC systems occurs as a result of both thermo-chemical and thermo-mechanical degradation. This research involves exploring both of these mechanisms for two distinctly different issues. The United States Navy is currently making a push to implement the use of alternative fuels by 2012, but the use of these fuels (syngas, high hydrogen content, and alternatives to JP-8) presents significant materials durability challenges. Initial data suggests that high water vapor levels, high sulfur concentrations, and ash deposits from fuel impurities lead to unique, and severe, degradation modes. This research is aimed at addressing the effects of differing combustion environment characteristics on the corrosion and oxidation of TBC systems. On the industrial front, there is a constant driver to better understand and predict coating failure, particularly in air-plasma sprayed (APS) TBC systems. The morphology of the metal-ceramic interface is known to play a key role in the generation of compressive and tensile stresses that eventually cause coating failure in typical engine environments. Experimental evidence and field experience have shown that a tortuous interface is generally beneficial to coating lifetime. Nevertheless, for the past 40 years engineers have struggled to find a functional correlation between BC topology and coating system lifetime. This document also addresses the progress that has been made toward the establishment of this functional correlation.

  4. Contribution à l'Etude des Disques Planétaires et Protoplanétaires Perturbés

    NASA Astrophysics Data System (ADS)

    Charnoz, Sébastien

    2000-11-01

    Nous avons étudié plusieurs aspects dynamiques et photométriques des disques planétaires et protoplanétaires perturbés. Dans la première partie, à l'aide de modèles numériques simples, nous avons étudié l'eacute;volution thermodynamique d'un disque protoplanétaire composé de planétésimaux subissant des collisions physiques inélastiques, au voisinage d'un embryon de planète géante (~ 15 masses terrestres). Dès l'apparition de l'embryon planétaire, un transfert de chaleur se met en place dans le disque, augmentant fortement les vitesses relatives dans ce dernier, sur une région s'étendant sur plusieurs unités astronomiques. L'évolution de ce mécanisme transitoire a été étudiée sur des temps longs (un million d'années) et pour une vaste gamme demasses du perturbateur. C'est un mécanisme générique qui pourrait avoir profondément affecté le processus de formation des planètes, aussi bien telluriques que géantes. Les conséquences sur la formation de la Ceinture d'Astéroïdes sont discutées, ainsi que l'effet possible de la fragmentation des planétésimaux, qui n'a pu être prise en compte dans le modèle numérique. La deuxième partie de cette thèse est une étude photométrique de l'anneau F de Saturne, qui est perturbé par ses deux satellites gardiens. En étudiant un ensemble de plus de 300 images prises au télescope CFH, nous avons mis en évidence la présence de structures étendues, dont l'origine est toujours mal connue. En combinant nos données et celles du télescope spatial, nous avons établi avec précision une nouvelle orbite de l'anneau F, à 140060+/-60 km, soit plus faible de 150 km par rapport à celle déterminée en 1980-81. Cecipourrait être le signe qu'une important restructuration radiale de l'anneau F a dû avoir lieu entre 1980 et 1995.

  5. The informative contribution of the "virtual medical visit" in a new heart failure telemedicine integrated system.

    PubMed

    Romano, Maria Francesca; Sardella, Maria Vittoria; Alboni, Fabrizio; L'Abbate, Antonio; Mariotti, Rita; Di Bello, Vitantonio

    2014-06-01

    Telemedicine systems consist of collection, transmission, and analysis of biometric data essentially based on instrumental measures. Our goal was to evaluate if information collected from patients has an incremental informative value in automatically rating the patient's health status. We present preliminary results of a new telemedicine system (ASCOLTA) obtained by observation of 12 heart failure patients (New York Heart Association Class IIb-III). Instrumental data (electrocardiogram, oxygen saturation level, and respiration rate) were wirelessly collected daily together with clinical data (weight, heart rate, and blood pressure values) and patients' information obtained through a Web-based questionnaire, simulating a virtual medical visit. Health status was independently judged by two blinded cardiologists and by the patient's cardiologist on the basis of 348 daily clinical reports. Random forest classification analysis was applied to 240 complete clinical report variables in order to estimate the judged health status. The use of "patient's information" led to a better predictive ability in comparison with using only physiological parameters assessed by instruments. The complete set of variables (Patient+Instrumental) achieved 84% concordance, compared with 72% for the instrumental-only variables and 69% for the patient-only variables. The receiver operator characteristics curves graphically confirmed the described results. Patients have an active role in home monitoring, and their information appears relevant for a new telemedicine approach integrating subjective and objective vital signs. Combining patient information with instrumental parameters, it is possible to achieve a more correct automatic classification of health status of heart failure patients.

  6. T-Tubular Electrical Defects Contribute to Blunted β-Adrenergic Response in Heart Failure

    PubMed Central

    Crocini, Claudia; Coppini, Raffaele; Ferrantini, Cecilia; Yan, Ping; Loew, Leslie M.; Poggesi, Corrado; Cerbai, Elisabetta; Pavone, Francesco S.; Sacconi, Leonardo

    2016-01-01

    Alterations of the β-adrenergic signalling, structural remodelling, and electrical failure of T-tubules are hallmarks of heart failure (HF). Here, we assess the effect of β-adrenoceptor activation on local Ca2+ release in electrically coupled and uncoupled T-tubules in ventricular myocytes from HF rats. We employ an ultrafast random access multi-photon (RAMP) microscope to simultaneously record action potentials and Ca2+ transients from multiple T-tubules in ventricular cardiomyocytes from a HF rat model of coronary ligation compared to sham-operated rats as a control. We confirmed that β-adrenergic stimulation increases the frequency of Ca2+ sparks, reduces Ca2+ transient variability, and hastens the decay of Ca2+ transients: all these effects are similarly exerted by β-adrenergic stimulation in control and HF cardiomyocytes. Conversely, β-adrenergic stimulation in HF cells accelerates a Ca2+ rise exclusively in the proximity of T-tubules that regularly conduct the action potential. The delayed Ca2+ rise found at T-tubules that fail to conduct the action potential is instead not affected by β-adrenergic signalling. Taken together, these findings indicate that HF cells globally respond to β-adrenergic stimulation, except at T-tubules that fail to conduct action potentials, where the blunted effect of the β-adrenergic signalling may be directly caused by the lack of electrical activity. PMID:27598150

  7. Distinct contribution of working memory and social comprehension failures in neuropsychological impairment in schizophrenia.

    PubMed

    Nestor, Paul G; Niznikiewicz, Margaret; McCarley, Robert W

    2010-03-01

    Neuropsychological impairment represents a core characteristic of schizophrenia, but its underlying components have yet to be clearly established. Using a comprehensive battery of standardized measures of intelligence, declarative episodic memory, and executive function, we hypothesized that the variance in neuropsychological performance in schizophrenia may reflect at least 2 distinct sources related to failures of (a) the central executive division of working memory and (b) social comprehension. In comparison to age-matched controls, patients with schizophrenia showed not only overall reduced scores on Wechsler intelligence and memory scales and Wisconsin Card Sorting Test (WCST) of executive function, but they also demonstrated different patterns of performance for each of these tests. Hierarchical regression revealed executive attentional control, measured by Trails B performance speed, and social comprehension, measured by Wechsler IQ Comprehension and Picture Arrangement subtests, each accounted for a unique and specific proportion of variance in test scores for the patient group, even when controlling for general intelligence. Failures in social comprehension and executive attentional control may account for distinct sources of variance in the neuropsychological impairment of schizophrenia.

  8. Contribution of ventricular remodeling to pathogenesis of heart failure in rats.

    PubMed

    Brower, G L; Janicki, J S

    2001-02-01

    We previously reported an approximately 50% incidence of rats with symptoms of congestive heart failure (CHF) at 8 wk postinfrarenal aorto-caval fistula. However, it was not clear whether compensatory ventricular remodeling could continue beyond 8 wk or whether the remaining animals would have developed CHF or died. Therefore, the intent of this study was to complete the characterization of this model of sustained volume overload by determining the morbidity and mortality and the temporal response of left ventricular (LV) remodeling and function beyond 8 wk. The findings demonstrate an upper limit to LV hypertrophy and substantial increases in LV volume and compliance, matrix metalloproteinase activity, and collagen volume fraction associated with the development of CHF. There was an 80% incidence of morbidity and mortality following 21 wk of chronic volume overload. These findings indicate that the development of CHF is triggered by marked ventricular dilatation and increased compliance occurring once the myocardial hypertrophic response is exhausted.

  9. Contribution a l'etude des mecanismes de l'adhesion de la glace a differents materiaux et application a l'evaluation des materiaux glaciophobes

    NASA Astrophysics Data System (ADS)

    Ghalmi, Zahira

    Several Nordic countries with cold climates like Canada are often subjected to ice storms causing major economic and social losses. Ice or sticky snow adhesion on power network equipment can be a significant issue in transmission and distribution of electrical energy for companies operating in these regions. The costs of such events can be substantial, particularly due to the cessation of economic activities, equipment failures, deicing techniques (active methods), and population safety. Because of such events, power companies have understood the need to develop so-called superhydrophobic and/or icephobic surfaces, which can significantly reduce ice adhesion (passive methods). Several studies have led to the development of a variety of new nanostructured surfaces using various strategies. These studies have led to the design of superhydrophobic surfaces with contact angles greater than 150 and low ice adhesion strength. In order to optimally reduce the ice adhesion strength on different substrates, better understanding of the various mechanisms involved in the icing process is essential. It is in this context and within the framework of Canada's research chair on atmospheric icing of power networks (INGIVRE) that this thesis was carried out, aiming to improve the knowledge of atmospheric icing, and explain the forces involved at the ice/substrate interface. Furthermore, the effect of contact angle, surface roughness and porosity on icing and ice/substrate interface was investigated. This study clearly showed that the electrostatic, van der Waals and hydrogen bond forces are the main contributors to ice adhesion to a surface at the molecular level. The electrostatic energy, based on the principle of image charge, depends on the type of material in contact with the ice, the distance between the ice and the material, and the types of ice surface defects. The van der Waals energy depends on the material type, the thickness of the liquid water layer, and the temperature

  10. Direct Evidence that Myocardial Insulin Resistance following Myocardial Ischemia Contributes to Post-Ischemic Heart Failure

    PubMed Central

    Fu, Feng; Zhao, Kun; Li, Jia; Xu, Jie; Zhang, Yuan; Liu, Chengfeng; Yang, Weidong; Gao, Chao; Li, Jun; Zhang, Haifeng; Li, Yan; Cui, Qin; Wang, Haichang; Tao, Ling; Wang, Jing; Quon, Michael J; Gao, Feng

    2015-01-01

    A close link between heart failure (HF) and systemic insulin resistance has been well documented, whereas myocardial insulin resistance and its association with HF are inadequately investigated. This study aims to determine the role of myocardial insulin resistance in ischemic HF and its underlying mechanisms. Male Sprague-Dawley rats subjected to myocardial infarction (MI) developed progressive left ventricular dilation with dysfunction and HF at 4 wk post-MI. Of note, myocardial insulin sensitivity was decreased as early as 1 wk after MI, which was accompanied by increased production of myocardial TNF-α. Overexpression of TNF-α in heart mimicked impaired insulin signaling and cardiac dysfunction leading to HF observed after MI. Treatment of rats with a specific TNF-α inhibitor improved myocardial insulin signaling post-MI. Insulin treatment given immediately following MI suppressed myocardial TNF-α production and improved cardiac insulin sensitivity and opposed cardiac dysfunction/remodeling. Moreover, tamoxifen-induced cardiomyocyte-specific insulin receptor knockout mice exhibited aggravated post-ischemic ventricular remodeling and dysfunction compared with controls. In conclusion, MI induces myocardial insulin resistance (without systemic insulin resistance) mediated partly by ischemia-induced myocardial TNF-α overproduction and promotes the development of HF. Our findings underscore the direct and essential role of myocardial insulin signaling in protection against post-ischemic HF. PMID:26659007

  11. Nitrogen deposition potentially contributes to oak regeneration failure in the Midwestern temperate forests of the USA.

    PubMed

    BassiriRad, Hormoz; Lussenhop, John F; Sehtiya, Harbans L; Borden, Kara K

    2015-01-01

    We conducted a 7-year field study at two oak-dominated forest sites which differ in their atmospheric N deposition to test the hypothesis that red oak regeneration failure in the upper Midwestern US forests, at least in part, results from increased N load. The sites are located in Swallow Cliffs (SC) in Cook County, Illinois, and Indiana Dunes National Lakeshore (IDNL) in Porter County, Indiana. Annual wet NO3(-) deposition for the 22 years immediately prior to the experiments was significantly higher in IDNL than in the SC site. Results from common garden experiments showed that oak seedling biomass was 60% lower at IDNL compared with SC, but there was little site effect on growth of maple seedlings. Experimental N addition also resulted in a 45% decrease in the total biomass of the oak seedlings at SC, but had no significant effect on the biomass at IDNL. Maple seedlings responded little to experimental fertilization. The growth rate of mature oak trees was also lower at IDNL but to a much smaller extent than that of seedlings. Maple trees did not significantly differ between sites. We conclude that: (1) chronic N load adversely affects seedling performance of red oak, but not sugar maple, in these temperate forests; and (2) the seedling establishment phase rather than the adult tree is the likely target stage for this adverse effect of N loading. The exact mechanisms for the differential effects of N on these co-occurring species are not clear, but different plasticity in fractional biomass and N allocation to the leaves might be involved.

  12. Contribution of Transjugular Liver Biopsy in Patients with the Clinical Presentation of Acute Liver Failure

    SciTech Connect

    Miraglia, Roberto Luca, Angelo; Gruttadauria, Salvatore; Minervini, Marta Ida; Vizzini, Giovanni; Arcadipane, Antonio; Gridelli, Bruno

    2006-12-15

    Purpose. Acute liver failure (ALF) treated with conservative therapy has a poor prognosis, although individual survival varies greatly. In these patients, the eligibility for liver transplantation must be quickly decided. The aim of this study was to assess the role of transjugular liver biopsy (TJLB) in the management of patients with the clinical presentation of ALF. Methods. Seventeen patients with the clinical presentation of ALF were referred to our institution during a 52 month period. A TJLB was performed using the Cook Quick-Core needle biopsy. Clinical data, procedural complications, and histologic findings were evaluated. Results. Causes of ALF were virus hepatitis B infection in 7 patients, drug toxicity in 4, mushroom in 1, Wilson's disease in 1, and unknown origin in 4. TJLB was technically successful in all patients without procedure-related complications. Tissue specimens were satisfactory for diagnosis in all cases. In 14 of 17 patients the initial clinical diagnosis was confirmed by TJLB; in 3 patients the initial diagnosis was altered by the presence of unknown cirrhosis. Seven patients with necrosis <60% were successfully treated with medical therapy; 6 patients with submassive or massive necrosis ({>=}85%) were treated with liver transplantation. Four patients died, 3 had cirrhosis, and 1 had submassive necrosis. There was a strict statistical correlation (r = 0.972, p < 0.0001) between the amount of necrosis at the frozen section examination and the necrosis found at routine histologic examination. The average time for TJLB and frozen section examination was 80 min. Conclusion. In patients with the clinical presentation of ALF, submassive or massive liver necrosis and cirrhosis are predictors of poor prognosis. TLJB using an automated device and frozen section examination can be a quick and effective tool in clinical decision-making, especially in deciding patient selection and the best timing for liver transplantation.

  13. Endothelial Senescence Contributes to Heart Failure With Preserved Ejection Fraction in an Aging Mouse Model.

    PubMed

    Gevaert, Andreas B; Shakeri, Hadis; Leloup, Arthur J; Van Hove, Cor E; De Meyer, Guido R Y; Vrints, Christiaan J; Lemmens, Katrien; Van Craenenbroeck, Emeline M

    2017-06-01

    Because of global aging, the prevalence of heart failure with preserved ejection fraction (HFpEF) continues to rise. Although HFpEF pathophysiology remains incompletely understood, endothelial inflammation is stated to play a central role. Cellular senescence is a process of cellular growth arrest linked with aging and inflammation. We used mice with accelerated aging to investigate the role of cellular senescence in HFpEF development. Senescence-accelerated mice (SAM, n=18) and control mice with normal senescence (n=15) were fed normal chow or a high-fat, high-salt diet (WD). Vascular and cardiac function was assessed at 8, 16, and 24 weeks of age. At 24 weeks, both SAM on WD (SAM-WD) and SAM on regular diet displayed endothelial dysfunction, as evidenced by impaired acetylcholine-induced relaxation of aortic segments and reduced basal nitric oxide. At week 24, SAM-WD had developed HFpEF, characterized by diastolic dysfunction, left ventricular hypertrophy, left atrial dilatation, and interstitial fibrosis. Also, exercise capacity was reduced and lung weight increased. Cardiovascular inflammation and senescence were assessed by immunohistochemical and immunofluorescence staining of hearts and aortas. SAM-WD showed increased endothelial inflammation (intercellular adhesion molecule 1 expression) and increased endothelial senescence (acetyl-p53/CD31 costaining). The latter correlated with diastolic function and intercellular adhesion molecule 1 expression. SAM develop endothelial dysfunction. Adding a high-salt, high-fat diet accelerates endothelial senescence and instigates endothelial inflammation. This coincides with hemodynamic and structural changes typical of HFpEF. Targeting endothelial senescence could be a new therapeutic avenue in HFpEF. © 2017 American Heart Association, Inc.

  14. Relative contribution of resting haemodynamic profile and lung function to exercise tolerance in male patients with chronic heart failure

    PubMed Central

    Faggiano, P; D'Aloia, A; Gualeni, A; Giordano, A

    2001-01-01

    OBJECTIVE—To clarify the relative contribution of resting haemodynamic profile and pulmonary function to exercise capacity in patients with heart failure.
SETTING—Cardiology department and cardiac rehabilitation unit in a tertiary centre.
DESIGN—161 male patients (mean (SD) age 59 (9) years) with heart failure (New York Heart Association class II-IV, left ventricular ejection fraction 23 (7)%) underwent spirometry, alveolar capillary diffusing capacity (DLCO), and mouth inspiratory and expiratory pressures (MIP, MEP, respectively, in 100 patients). Right heart catheterisation and a symptom limited cardiopulmonary exercise test were performed in 137 patients within 3-4 days.
RESULTS—Mean peak exercise oxygen consumption (V̇O2) was 13 (3.9) ml/kg/min. Among resting haemodynamic variables only cardiac index showed a significant correlation with peak V̇O2. There were no differences in haemodynamic variables between patients with peak V̇O2 ⩽ or > 14 ml/kg/min. There was a moderate correlation (p < 0.05) between several pulmonary function variables and peak V̇O2. Forced vital capacity (3.5 (0.9) v 3.2 (0.8) l, p < 0.05) and DLCO (21.6 (6.9) v 17.7 (5.5) ml/mm Hg/min, p < 0.05) were higher in patients with peak V̇O2 > 14 ml/kg/min than in those with peak V̇O2 ⩽ 14 ml/kg/min. Using a stepwise regression analysis, the respiratory and haemodynamic variables which correlated significantly with peak V̇O2 were DLCO, MEP, and cardiac index, with an overall R value of 0.63.
CONCLUSIONS—The data confirm previous studies showing a poor correlation between resting indices of cardiac function and exercise capacity in heart failure. However, several pulmonary function variables were related to peak exercise V̇O2. In particular, lung diffusing capacity and respiratory muscle function seem to affect exercise tolerance during heart failure.


Keywords: heart failure; exercise; pulmonary function; alveolar-capillary diffusing

  15. The contribution of stem cell therapy to skeletal muscle remodeling in heart failure.

    PubMed

    Castellani, Chiara; Vescovo, Giorgio; Ravara, Barbara; Franzin, Chiara; Pozzobon, Michela; Tavano, Regina; Gorza, Luisa; Papini, Emanuele; Vettor, Roberto; De Coppi, Paolo; Thiene, Gaetano; Angelini, Annalisa

    2013-10-03

    The aim of our study was to investigate whether stem cell (SC) therapy with human amniotic fluid stem cells (hAFS, fetal stem cells) and rat adipose tissue stromal vascular fraction cells-GFP positive cells (rSVC-GFP) was able to produce favorable effects on skeletal muscle (SM) remodeling in a well-established rat model of right heart failure (RHF). RHF was induced by monocrotaline (MCT) in Sprague-Dawley rats. Three weeks later, four millions of hAFS or rSVC-GFP cells were injected via tail vein. SM remodeling was assessed by Soleus muscle fiber cross sectional area (CSA), myocyte apoptosis, myosin heavy chain (MHC) composition, satellite cells pattern, and SC immunohistochemistry. hAFS and rSVC-GFP injection produced significant SC homing in Soleus (0.68 ± 1.0 and 0.67 ± 0.75% respectively), with a 50% differentiation toward smooth muscle and endothelial cells. Pro-inflammatory cytokines were down regulated to levels similar to those of controls. SC-treated (SCT) rats showed increased CSA (p<0.004 vs MCT) similarly to controls with a reshift toward the slow MHC1 isoform. Apoptosis was significantly decreased (11.12.± 8.8 cells/mm(3) hAFS and 13.1+7.6 rSVC-GFP) (p<0.001 vs MCT) and similar to controls (5.38 ± 3.0 cells/mm(3)). RHF rats showed a dramatic reduction of satellite cells(MCT 0.2 ± 0.06% Pax7 native vs controls 2.60 ± 2.46%, p<0.001), while SCT induced a repopulation of both native and SC derived satellite cells (p<0.005). SC treatment led to SM remodeling with satellite cell repopulation, decreased atrophy and apoptosis. Modulation of the cytokine milieu might play a crucial pathophysiological role with a possible scenario for autologous transplantation of SC in pts with CHF myopathy. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. La contribution de la diversité des expériences littéraires préscolaires aux habiletés émergentes en littéracie

    PubMed Central

    PARENT, Sophie; MONTÉSINOS-GELET, Isabelle; SÉGUIN, Jean R.; ZELAZO, Philip David; TREMBLAY, Richard E.

    2017-01-01

    RÉSUMÉ Les études antérieures montrent que les facteurs langagiers et cognitifs chez le jeune enfant ne suffisent pas pour expliquer les différences individuelles dans l’acquisition des compétences relatives à la langue écrite (Sénéchal et LeFevre, 2002). S’inspirant de l’éthologie et de la sociologie, Pellegrini (2001) propose que l’exposition à une plus grande variété d’interlocuteurs et de contextes sociaux pour l’exercice des compétences liées à l’écrit favorise l’acquisition du langage littéraire et des compétences en lecture/écriture. La présente étude a pour but de vérifier cette contribution de la variété des opportunités sociales reliées à l’écrit à l’acquisition des compétences émergentes en littéracie à 5 ans. Cette contribution est examinée de concert avec les ressources financières familiales, l’éducation parentale, la fréquence des activités mère-enfant de lecture/écriture et les compétences verbales et mnémoniques de l’enfant. Les résultats confirment partiellement l’hypothèse de Pellegrini et appuient la pertinence de considérer plusieurs dimensions des expériences sociales préscolaires. La contribution unique de la diversité des activités littéraires de l’enfant à 48 mois s’avère de taille similaire à celle du vocabulaire réceptif évalué à 42 mois et de la mémoire à court terme à 42 mois. La diversité des interlocuteurs n’ajoute toutefois pas au modèle. PMID:28566801

  17. Contributions of Comorbid Diabetes to Sleep Characteristics, Daytime Symptoms, and Physical Function among Patients with Stable Heart Failure

    PubMed Central

    Fritschi, Cynthia; Redeker, Nancy S.

    2014-01-01

    Background Diabetes (DM) and heart failure (HF) are often comorbid. Sleep disturbances, poor physical functioning, and high levels of daytime symptoms are prevalent and contribute to poor quality of life in both populations. However, little is known about the independent and additive effects of comorbid DM on sleep, physical function, and daytime symptoms among patients with HF. Objective To investigate the extent to which comorbid DM confers independent and additive effects on sleep disturbance, physical functioning, and symptoms among patients with stable HF. Methods This secondary analysis was conducted on a sample of 173 stable Class II-IV HF patients. Self-report and polysomnography were used to measure sleep quality, objective sleep characteristics, and sleep disordered breathing. Physical function measures included wrist actigraphy, the six minute walk test, and the SF-36 Physical Component Summary Score. Fatigue, sleepiness, and depression were also measured. Univariate analyses and hierarchical regression models were computed. Results The sample included 173 (n = 119/68% HF and n = 54/32% HF plus DM) patients (age 60.4 ± 16.1 years). In analyses adjusted for age, gender, BMI, and NY Heart Association classification, HF patients with DM had longer sleep latency and spent a greater percentage of time awake after sleep onset (WASO %] than the HF patients who did not have DM (all p < .05). There were no statistically significant differences in respiratory disturbance index (RDI) or self-reported sleep quality. Sleep duration was low in both groups. Patients with DM had shorter 6MWT distance, lower ratio of daytime to nighttime activity, and lower general health and self-reported physical function. Hierarchical regression models revealed that age and DM were the only significant correlates of the sleep variables, while age, gender, NYHA class, and DM were all associated with 6MWT distance. Conclusions Comorbid DM contributes independent and additive effects on

  18. Contribution des acteurs régionaux à la réduction des inégalités sociales de santé : le cas de la France.

    PubMed

    Stachenko, Sylvie; Pommier, Jeanine; You, Cécile; Porcherie, Marion; Halley, Justine; Breton, Eric

    2015-09-24

    Depuis le rapport de la Commission sur les Déterminants Sociaux de la Santé, plusieurs pays ont commencé à intégrer à leurs plans de santé la question des déterminants et de leur impact sur les inégalités de santé. En France, la création des Agences Régionales de Santé en 2009 est considérée comme une opportunité pour agir sur les inégalités sociales de santé (ISS) avec les instances régionales, départementales et locales qui détiennent les leviers appropriés. A la suite d'une analyse thématique des projets régionaux de santé, visant à identifier l'intégration des ISS ainsi que les approches retenues pour les aborder, quatre régions ont été étudiées plus finement. Des entretiens collectifs et individuels (N = 45 interviewés) ont été menés auprès d'acteurs de terrain et institutionnels, afin de mieux comprendre et identifier les types de programmes et processus pour réduire les ISS. Nos analyses font ressortir une prise en compte généralisée des ISS dans les documents de planification et de programmation des instances régionales, des stratégies régionales qui restent centrées sur les populations vulnérables avec une faible considération du gradient social, l'existence d'instances de concertations intersectorielles dans les quatre régions qui constituent un potentiel de gouvernance important à mieux exploiter, l'existence de modalités de suivi et d'évaluation des ISS qui restent à consolider, et une forte mobilisation de plusieurs secteurs dans les processus régionaux de consultation des publics et des acteurs, mais des résultats variables, souvent reliés au niveau de ressources investies et des approches privilégiées. L'analyse de ces expériences françaises démontre un intérêt croissant pour l'action sur les déterminants sociaux de la santé et les ISS ; mais leur opérationnalisation, toujours en cours, appelle à des analyses plus fines qui permettront de mieux éclairer les politiques publiques.

  19. Contribution a l'etude du comportement de dalles de ponts en beton arme de barres en PRF soumises a des charges concentrees simulant les charges de roues

    NASA Astrophysics Data System (ADS)

    Bouguerra, Kheireddine

    Au cours des dernieres annees, la deterioration des structures en beton arme a pris une ampleur sans precedent, et ce, malgre le fait que leur duree de vie en service initialement prevue est loin d'etre atteinte. La corrosion de l'armature d'acier est un des principaux facteurs reduisant la duree de vie des ponts en beton arme d'acier. Par ailleurs, l'armature en materiaux composites de polymeres renforces de fibres (PRF) constitue une solution a l'armature metallique afin de pallier au probleme de la corrosion d'acier et a la deterioration des structures en beton arme. Aussi, les barres d'armature en materiaux composites de PRF possedent une resistance en traction elevee (environ 2 a 6 fois la limite elastique de l'acier d'armature conventionnel), ce qui leur permet de constituer un renforcement structural attrayant pour les structures en beton. Le comportement d'elements structuraux en beton arme de barres en PRF est different de ceux en beton arme de barres d'acier. En effet, les barres en PRF possedent un module d'elasticite relativement plus faible que celui de l'acier et ont des proprietes d'adherence differentes de celles des barres d'acier. L'utilisation des barres d'armature en PRF pour armer les dalles de tabliers de ponts se concretise de plus en plus avec l'avancement des recherches dans ce domaine. La recherche entamee dans le cadre de cette these s'inscrit dans un programme de travaux realises au sein de la Chaire de recherche CRSNG/Industrie sur les Materiaux composites novateurs en PRF pour les infrastructures au departement de genie civil a l'Universite de Sherbrooke. Le comportement de membrures en beton arme de PRF soumis a des sollicitations mecaniques constitue un des principaux axes de recherche. Dans le cadre de cette these, une serie d'essais a ete effectuee sur huit dalles de ponts a confinement interne a grande echelle. Les parametres des essais comprennent: (1) l'epaisseur de la dalle, (2) le type et le taux d'armature transversale de l

  20. Contribution of right-sided heart enlargement to cardiomegaly on chest roentgenogram in diastolic and systolic heart failure.

    PubMed

    Fukuta, Hidekatsu; Ohte, Nobuyuki; Brucks, Steffen; Carr, J Jeffrey; Little, William C

    2007-01-01

    We investigated the contribution of a dilated right-sided heart to roentgenographic cardiomegaly in patients with heart failure (HF) and a normal ejection fraction (EF; diastolic HF) and those with HF and a decreased EF (systolic HF). We compared the cardiothoracic ratio (CTR) on upright chest roentgenograms and major- and minor-axis dimensions of the 4 cardiac chambers on echocardiograms in patients with HF and a normal EF (> or =0.50, n = 35) and those with a decreased EF (<0.50, n = 37) and examined the correlation between the CTR and cardiac chamber dimensions. The CTR did not differ between patients with normal and decreased EF values (0.58 +/- 0.07 vs 0.60 +/- 0.06, p = 0.26). Left-side cardiac chamber dimensions were substantially smaller in patients with a normal EF than in those with a decreased EF (left ventricular minor-axis dimension, 4.4 +/- 0.7 vs 5.8 +/- 0.8 cm, p <0.001). In contrast, right-side cardiac chamber dimensions were generally similar between groups. The CTR correlated with major-axis dimensions of the right ventricle and right atrium (p <0.01 for the 2 comparisons), but not with the left-side cardiac chamber dimensions (all p values >0.05). In conclusion, the CTR predominantly reflects right- rather than left-sided heart size in patients with HF. Right-sided heart size is similar between patients with normal and decreased EF values. Thus, despite the substantial difference in left ventricular size and EF, there is substantial overlap in the CTR between patients with diastolic and systolic HFs and the CTR is unable to discriminate between groups.

  1. Pharmacological evidence that a failure to recruit NMDA receptors contributes to impaired fear extinction retention in adolescent rats.

    PubMed

    Baker, Kathryn D; Richardson, Rick

    2016-11-01

    Adolescents, both humans and rodents, exhibit a marked impairment in extinction of fear relative to younger and older groups which could be caused by a failure to efficiently recruit NMDA receptors (NMDARs) in adolescence. It is well-established that systemic administration of NMDAR antagonists (e.g., MK801) before extinction training impairs the retention of extinction in adult and juvenile rodents, but it is unknown whether this is also the case for adolescents. Therefore, in the present study we investigated the effect of pharmacologically manipulating the NMDAR on extinction retention in adolescent rats. When extinction retention is typically impaired (i.e., after one session of extinction training) adolescent male rats given d-cycloserine (a partial NMDAR agonist) showed enhanced extinction retention relative to saline-treated animals while animals given MK801 (a non-competitive antagonist) did not exhibit any further impairment of extinction retention relative to the controls. In a further two experiments we demonstrated that when two sessions of extinction training separated by either 4 or 24h intervals were given to adolescent rats, saline-treated animals exhibited good extinction retention and the animals given MK801 before the second session exhibited impaired extinction retention. These findings suggest that extinction in adolescence does not initially involve NMDARs and this is a likely mechanism that contributes to the impaired fear inhibition observed at this age. However, NMDARs appear to be recruited with extended extinction training or after administration of a partial agonist, both of which lead to effective extinction retention.

  2. Central Actions of the Chemokine Stromal Cell-Derived Factor-1 Contribute to Neurohumoral Excitation in Heart Failure Rats

    PubMed Central

    Wei, Shun-Guang; Zhang, Zhi-Hua; Yu, Yang; Weiss, Robert M.; Felder, Robert B.

    2012-01-01

    The ample expression of chemokines and their receptors by neurons in the brain suggests that they play a functional role beyond the coordination of inflammatory and immune responses. Growing evidence implicates brain chemokines in the regulation of neuronal activity and neurohormonal release. This study examined the potential role of brain chemokines in regulating hemodynamic, sympathetic and neuroendocrine mechanisms in rats with ischemia-induced heart failure (HF). Immunohistochemical analysis revealed that the chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 was highly expressed in the hypothalamic paraventricular (PVN) and subfornical organ, and that SDF-1 expression was significantly increased in HF rats compared with sham-operated (SHAM) control rats. Intracerebroventricular (ICV) injection of SDF-1 induced substantial and long-lasting increases in blood pressure (BP), heart rate (HR) and renal sympathetic nerve activity (RSNA) in both SHAM and HF rats, but responses were exaggerated in HF rats. Bilateral microinjection of SDF-1 into the PVN also elicited exaggerated increases in BP, HR and RSNA in the HF rats. A 4-hour ICV infusion of SDF-1 increased plasma levels of arginine vasopressin (AVP), adrenocorticotropic hormone (ACTH) and norepinephrine (NE) in normal rats, responses that were prevented by pretreatment with ICV SDF-1 short-hairpin RNA (shRNA). ICV administration of SDF-1 shRNA also reduced plasma AVP, ACTH and NE levels in HF rats. These data suggest that the chemokine SDF-1, acting within the brain, plays an important role in regulating sympathetic drive, neuroendocrine release, and hemodynamic function in normal and pathophysiological conditions, and so may contribute to the neural and humoral activation in HF. PMID:22493069

  3. Contributions of Comorbid Diabetes to Sleep Characteristics, Daytime Symptoms, and Physical Function Among Patients With Stable Heart Failure.

    PubMed

    Fritschi, Cynthia; Redeker, Nancy S

    2015-01-01

    Diabetes mellitus (DM) and heart failure (HF) are often comorbid. Sleep disturbances, poor physical functioning, and high levels of daytime symptoms are prevalent and contribute to poor quality of life in both populations. However, little is known about the independent and additive effects of comorbid DM on sleep, physical function, and daytime symptoms among patients with HF. The aim of this study was to investigate the extent to which comorbid DM confers independent and additive effects on sleep disturbance, physical functioning, and symptoms among patients with stable HF. This secondary analysis was conducted on a sample of 173 stable class II to IV HF patients. Self-report and polysomnography were used to measure sleep quality, objective sleep characteristics, and sleep-disordered breathing. Physical function measures included wrist actigraphy, the 6-minute walk test (6MWT), and the Medical Outcomes Study 36-item Short Form physical component summary score. Fatigue, sleepiness, and depression were also measured. Univariate analyses and hierarchical regression models were computed. The sample included 173 (n = 119/68% HF and n = 54/32% HF plus DM) patients (mean [SD] age, 60.4 [16.1] years). In analyses adjusted for age, gender, body mass index, and New York Heart Association classification, the HF patients with DM had longer sleep latency and spent a greater percentage of time awake after sleep onset than the HF patients who did not have DM (all P < 0.05). There were no statistically significant differences in Respiratory Disturbance Index or self-reported sleep quality. Sleep duration was low in both groups. The patients with DM had shorter 6MWT distance, lower ratio of daytime to nighttime activity, as well as lower general health and self-reported physical function. Hierarchical regression models revealed that age and DM were the only significant correlates of the sleep variables, whereas age, gender, New York Heart Association class, and DM were all

  4. Common variants in IL-17A/IL-17RA axis contribute to predisposition to and progression of congestive heart failure

    PubMed Central

    Sandip, Chaugai; Tan, Lun; Huang, Jin; Li, Qing; Ni, Li; Cianflone, Katherine; Wang, Dao Wen

    2016-01-01

    Abstract Heart failure is characterized by immune activation leading to production and release of proinflammatory cytokines. Interleukin 17A (IL-17A) is a proinflammatory cytokine and multiple lines of evidence from animal and human studies suggest crucial roles of IL-17A in heart failure. Therefore, we investigated whether common polymorphisms of genes IL17A and IL17RA (coding interleukin 17 receptor A) contribute to genetic predisposition to heart failure and adverse clinical outcomes associated with it. A total of 1713 adult patients with congestive heart failure and 1713 age- and sex-matched controls were genotyped for promoter single nucleotide polymorphisms (SNPs), rs2275913 and rs8193037 in IL17A and rs4819554 in IL17RA, to assess the relationship between individual SNPs and the risk of congestive heart failure. Results showed that rs8193037 in IL17A was associated with the risk of congestive heart failure (odds ratio [OR] = 0.76; 95% confidence interval [CI] 0.63–0.90, adjusted P = 0.002) after adjustment for multiple cardiovascular risk factors including age, sex, smoking status, diabetes, hypertension, and dyslipidemia. This association was evident in both ischemic and nonischemic heart failure (P = 0.005 and P = 0.05, respectively). Furthermore, prospective follow-up of 12.7 months for the occurrence of adverse clinical outcomes showed that rs4819554 in IL17RA was significantly associated with cardiovascular mortality (hazard ratio [HR] = 1.28; 95% CI = 1.02–1.59, adjusted P = 0.03) after adjustments for multiple cardiovascular risk factors and New York Heart Association functional class. This study demonstrated associations of rs8193037 in the promoter of IL17A with the risk of congestive heart failure, and of rs4819554 in the promoter of IL17RA with the risk of cardiovascular mortality in patients with congestive heart failure. These data lend further support to the notion that immune activation and genetic polymorphisms contribute to heart failure

  5. Common variants in IL-17A/IL-17RA axis contribute to predisposition to and progression of congestive heart failure.

    PubMed

    Sandip, Chaugai; Tan, Lun; Huang, Jin; Li, Qing; Ni, Li; Cianflone, Katherine; Wang, Dao Wen

    2016-07-01

    Heart failure is characterized by immune activation leading to production and release of proinflammatory cytokines. Interleukin 17A (IL-17A) is a proinflammatory cytokine and multiple lines of evidence from animal and human studies suggest crucial roles of IL-17A in heart failure. Therefore, we investigated whether common polymorphisms of genes IL17A and IL17RA (coding interleukin 17 receptor A) contribute to genetic predisposition to heart failure and adverse clinical outcomes associated with it.A total of 1713 adult patients with congestive heart failure and 1713 age- and sex-matched controls were genotyped for promoter single nucleotide polymorphisms (SNPs), rs2275913 and rs8193037 in IL17A and rs4819554 in IL17RA, to assess the relationship between individual SNPs and the risk of congestive heart failure. Results showed that rs8193037 in IL17A was associated with the risk of congestive heart failure (odds ratio [OR] = 0.76; 95% confidence interval [CI] 0.63-0.90, adjusted P = 0.002) after adjustment for multiple cardiovascular risk factors including age, sex, smoking status, diabetes, hypertension, and dyslipidemia. This association was evident in both ischemic and nonischemic heart failure (P = 0.005 and P = 0.05, respectively). Furthermore, prospective follow-up of 12.7 months for the occurrence of adverse clinical outcomes showed that rs4819554 in IL17RA was significantly associated with cardiovascular mortality (hazard ratio [HR] = 1.28; 95% CI = 1.02-1.59, adjusted P = 0.03) after adjustments for multiple cardiovascular risk factors and New York Heart Association functional class.This study demonstrated associations of rs8193037 in the promoter of IL17A with the risk of congestive heart failure, and of rs4819554 in the promoter of IL17RA with the risk of cardiovascular mortality in patients with congestive heart failure. These data lend further support to the notion that immune activation and genetic polymorphisms contribute to heart failure pathogenesis

  6. Mid-regional pro-adrenomedullin and ST2 in heart failure: Contributions to diagnosis and prognosis.

    PubMed

    Lopes, Daniela; Menezes Falcão, Luiz

    2017-06-01

    Heart failure has a high prevalence in developed countries. It is a frequent cause of hospital admission and has an important impact on morbidity, mortality and healthcare costs. Biomarkers have been widely studied in heart failure, as they improve diagnosis and prognostic assessment. Natriuretic peptides are already a part of daily clinical practice but several other biomarkers are being studied. This review focuses on mid-regional pro-adrenomedullin (MR-proADM) and ST2. Neither of these biomarkers is useful in the diagnosis of acute heart failure. However, both have considerable short- and long-term prognostic value in patients with acute and with stable chronic heart failure. The utility of these two biomarkers in guiding heart failure treatment is yet to be established. ST2 appears to have some advantages compared to MR-proADM, because it is more closely associated with ventricular remodeling and fibrosis. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Overt expression of AP-1 reduces alpha myosin heavy chain expression and contributes to heart failure from chronic volume overload.

    PubMed

    Freire, Grace; Ocampo, Catherina; Ilbawi, Nadim; Griffin, Andrew J; Gupta, Madhu

    2007-10-01

    Reduced expression of alpha-MHC plays a significant role in cardiac contractile dysfunction from hemodynamic overload. Previously, Pur proteins and YY1 have been shown to play a role in alpha-MHC repression during heart failure induced by pressure overload and by spontaneous hypertension, respectively. This was not observed in volume-overload-induced heart failure, suggesting additional regulatory mechanisms for alpha-MHC repression. The present study was performed to identify volume overload responsive transcription factors involved in alpha-MHC gene regulation. DNA binding activity of several transcription factors was evaluated in a functionally characterized rat model of heart failure induced by aorto-caval shunt. After 10 weeks of shunt, severe LV dilatation and reduced LV function were accompanied by increased expression of ANF and beta-MHC, and decreased expression of alpha-MHC. This was associated with dramatic (10-fold) activation of AP-1 together with increased expression of c-fos and c-jun. AP-1 activation was not observed following 4 weeks of shunt when cardiac function was preserved. In cultured cardiomyocytes, induction of AP-1 by PMA attenuated alpha-MHC mRNA by 60%. Transient transfection assays mapped PMA responsive sequence to -582 to -588 bp of alpha-MHC promoter. Deletion or mutation of these nucleotides had minimal effect on basal promoter activity but played a dominant role in PMA-mediated repression of alpha-MHC promoter activity. Over-expression of c-fos and c-jun in cardiomyocytes inhibited alpha-MHC promoter activity in a concentration dependent manner. Data suggest a repressive role of AP-1 in alpha-MHC expression and its possible involvement in the transition from compensatory hypertrophy to heart failure in chronic volume overload.

  8. The internal model: A study of the relative contribution of proprioception and visual information to failure detection in dynamic systems. [sensitivity of operators versus monitors to failures

    NASA Technical Reports Server (NTRS)

    Kessel, C.; Wickens, C. D.

    1978-01-01

    The development of the internal model as it pertains to the detection of step changes in the order of control dynamics is investigated for two modes of participation: whether the subjects are actively controlling those dynamics or are monitoring an autopilot controlling them. A transfer of training design was used to evaluate the relative contribution of proprioception and visual information to the overall accuracy of the internal model. Sixteen subjects either tracked or monitored the system dynamics as a 2-dimensional pursuit display under single task conditions and concurrently with a sub-critical tracking task at two difficulty levels. Detection performance was faster and more accurate in the manual as opposed to the autopilot mode. The concurrent tracking task produced a decrement in detection performance for all conditions though this was more marked for the manual mode. The development of an internal model in the manual mode transferred positively to the automatic mode producing enhanced detection performance. There was no transfer from the internal model developed in the automatic mode to the manual mode.

  9. Identification of corrosion and damage mechanisms by using scanning electron microscopy and energy-dispersive X-ray microanalysis: contribution to failure analysis case histories

    NASA Astrophysics Data System (ADS)

    Pantazopoulos, G.; Vazdirvanidis, A.

    2014-03-01

    Emphasis is placed on the evaluation of corrosion failures of copper and machineable brass alloys during service. Typical corrosion failures of the presented case histories mainly focussed on stress corrosion cracking and dezincification that acted as the major degradation mechanisms in components used in piping and water supply systems. SEM assessment, coupled with EDS spectroscopy, revealed the main cracking modes together with the root-source(s) that are responsible for the damage initiation and evolution. In addition, fracture surface observations contributed to the identification of the incurred fracture mechanisms and potential environmental issues that stimulated crack initiation and propagation. Very frequently, the detection of chlorides among the corrosion products served as a suggestive evidence of the influence of working environment on passive layer destabilisation and metal dissolution.

  10. Environmental contributions to fatigue failure of micron-scale silicon films used in microelectromechanical system (MEMS) devices

    NASA Astrophysics Data System (ADS)

    Pierron, Olivier

    Over the past 40 years, the silicon semiconductor industry has explored critical properties of the silicon dioxide (SiO2)/silicon (Si) materials system. The recent advent of Si-based microelectromechanical system (MEMS) devices has, however, required new focus on the structural reliability of micron-scale Si films. The discovery over a decade ago of delayed failure for silicon films in room-temperature air caused active research to capture the underlying mechanism(s) for the fatigue process. This investigation established that the evolution of nanometer-scale surface oxide layers on micron-scale silicon films is a critical part in the fatigue damage accumulation process. The importance of service environment to the fatigue resistance of n +-type, 10 mum thick, single-crystal silicon structural films was characterized by evaluating the response of electrostatically-actuated resonators (natural frequency, f0, ˜40kHz) in controlled atmospheres. A testing methodology was developed to accurately measure stress amplitude and lifetime in humid air and vacuum environments. A short-life testing technique was introduced to measure with precision fatigue lives as low as a few hundred cycles from kHz-frequency resonators. Stress-life ( S-N) fatigue tests conducted in 30°C, 50% relative humidity (R.H.) air demonstrated the fatigue susceptibility of these films. Further characterization of the films in medium vacuum and 25% R.H. air at various stress amplitudes revealed that the rates of fatigue damage accumulation (measured via resonant frequency changes) were strongly sensitive to both stress amplitude and, more importantly, humidity. Scanning electron microcopy of high-cycle fatigue fracture surfaces (cycles to failure, Nf > 1 x 10 9) revealed clear failure origins that were not observed in short-life (Nf < 1 x 104) specimens. Similar results were observed for the fatigue testing of 2 mum thick, n+-type polycrystalline silicon films consisting of ˜100 nm equiaxed grains

  11. 29 CFR 4043.81 - PBGC Form 200, notice of failure to make required contributions; supplementary information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sponsor of a single-employer plan that is covered under section 4021 of ERISA and, if that contributing sponsor is a member of a parent-subsidiary controlled group, the ultimate parent must complete and submit... the ultimate parent completes and submits Form 200 in accordance with this section, the PBGC...

  12. Purinergic signalling in the rostral ventro-lateral medulla controls sympathetic drive and contributes to the progression of heart failure following myocardial infarction in rats.

    PubMed

    Marina, Nephtali; Tang, Feige; Figueiredo, Melina; Mastitskaya, Svetlana; Kasimov, Vitaliy; Mohamed-Ali, Vidya; Roloff, Eva; Teschemacher, Anja G; Gourine, Alexander V; Kasparov, Sergey

    2013-01-01

    Heart failure may lead to hypoperfusion and hypooxygenation of tissues and this is often exacerbated by central and obstructive sleep apnoeas associated with recurrent episodes of systemic hypoxia which triggers release of ATP within the CNS circuits controlling sympathetic outflow. Using in vitro and in vivo models we tested two hypotheses: (1) activated brainstem astroglia release ATP and via release of ATP activate sympathoexcitatory neurones of the rostral ventrolateral medulla (RVLM); and (2) ATP actions in the RVLM contribute to sympathoexcitation, progression of left ventricular (LV) remodelling and development heart failure secondary to myocardial infarction. In vitro, optogenetic activation of RVLM astrocytes transduced to express light-sensitive channelrhodopsin-2 activated sympathoexcitatory RVLM neurones in ATP-dependent manner. In anaesthetised rats in vivo, similar optogenetic activation of RVLM astrocytes increased sympathetic renal nerve activity, arterial blood pressure and heart rate. To interfere with ATP-mediated signalling by promoting its extracellular breakdown, we developed a lentiviral vector to express an ectonucleotidase--transmembrane prostatic acid phosphatase (TMPAP) on the cellular membranes. In rats with myocardial infarction-induced heart failure, expression of TMPAP bilaterally in the RVLM led to lower plasma noradrenaline concentration, maintained left ventricular end diastolic pressure, attenuated decline in dP/dT (max) and shifted the LV pressure-volume relationship curve to the left. These results show that activated RVLM astrocytes are capable of increasing sympathetic activity via release of ATP while facilitated breakdown of ATP in the RVLM attenuates the progression of LV remodelling and heart failure secondary to myocardial infarction.

  13. Cellular Aging Contributes to Failure of Cold-Induced Beige Adipocyte Formation in Old Mice and Humans.

    PubMed

    Berry, Daniel C; Jiang, Yuwei; Arpke, Robert W; Close, Elizabeth L; Uchida, Aki; Reading, David; Berglund, Eric D; Kyba, Michael; Graff, Jonathan M

    2017-01-10

    Cold temperatures induce progenitor cells within white adipose tissue to form beige adipocytes that burn energy and generate heat; this is a potential anti-diabesity therapy. However, the potential to form cold-induced beige adipocytes declines with age. This creates a clinical roadblock to potential therapeutic use in older individuals, who constitute a large percentage of the obesity epidemic. Here we show that aging murine and human beige progenitor cells display a cellular aging, senescence-like phenotype that accounts for their age-dependent failure. Activating the senescence pathway, either genetically or pharmacologically, in young beige progenitors induces premature cellular senescence and blocks their potential to form cold-induced beige adipocytes. Conversely, genetically or pharmacologically reversing cellular aging by targeting the p38/MAPK-p16(Ink4a) pathway in aged mouse or human beige progenitor cells rejuvenates cold-induced beiging. This in turn increases glucose sensitivity. Collectively, these data indicate that anti-aging or senescence modalities could be a strategy to induce beiging, thereby improving metabolic health in aging humans. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Failure of stress-induced downregulation of Bcl-2 contributes to apoptosis resistance in senescent human diploid fibroblasts.

    PubMed

    Ryu, S J; Oh, Y S; Park, S C

    2007-05-01

    We previously reported that senescent human diploid fibroblasts (HDFs) are resistant to apoptosis induced by H(2)O(2) and staurosporine. We report here that senescent HDFs are resistant to thapsigargin-induced apoptosis as well. These agonists caused the reductions in mitochondrial membrane potential (MMP) and in the apoptosis inhibitory protein (B-cell lymphoma) only in young HDFs but not in senescent HDFs. In addition, downregulation of Bcl-2 increased the sensitivity of senescent HDFs to apoptosis induction, suggesting the significant role of Bcl-2 in apoptosis resistance of the senescent HDFs. We further found that P-cAMP response element-binding protein (CREB), a positive regulator of Bcl-2, decreased in stress-induced apoptosis of young HDFs but not in senescent HDFs, and that Bcl-2 was markedly reduced in CREB small interfering RNA (siRNA), transfected senescent HDFs. In addition, activity of protein phosphatase 2A (PP2A), which dephosphorylates p-CREB, significantly increased in young HDFs but not in senescent HDFs treated with H(2)O(2), staurosporine or thapsigargin. Taken together, these results suggest that failure of stress-induced downregulation of Bcl-2 underlies resistance of senescent HDFs to apoptosis.

  15. Myocardial Stiffness in Patients with Heart Failure and a Preserved Ejection Fraction: Contributions of Collagen and Titin

    PubMed Central

    Zile, Michael R.; Baicu, Catalin F.; Ikonomidis, John; Stroud, Robert E.; Nietert, Paul J.; Bradshaw, Amy D.; Slater, Rebecca; Palmer, Bradley M.; Van Buren, Peter; Meyer, Markus; Redfield, Margaret; Bull, David; Granzier, Henk; LeWinter, Martin M.

    2015-01-01

    Background The purpose of this study was to determine whether patients with heart failure and a preserved ejection fraction (HFpEF) have an increase in passive myocardial stiffness and the extent to which discovered changes are dependent on changes in extracellular matrix fibrillar collagen and/or cardiomyocyte titin. Methods and Results Seventy patients undergoing coronary artery bypass grafting underwent an echocardiogram, plasma biomarker determination, and intra-operative left ventricular (LV) epicardial anterior wall biopsy. Patients were divided into 3 groups: referent control (n=17, no hypertension or diabetes), hypertension (HTN) without(-) HFpEF (n=31), and HTN with(+) HFpEF (n=22). One or more of the following studies were performed on the biopsies: passive stiffness measurements to determine total, collagen-dependent and titin-dependent stiffness (differential extraction assay), collagen assays (biochemistry or histology), or titin isoform and phosphorylation assays. Compared with controls, patients with HTN(-)HFpEF had no change in LV end diastolic pressure (LVEDP), myocardial passive stiffness, collagen, or titin phosphorylation but had an increase in biomarkers of inflammation (CRP, sST2, TIMP-1). Compared with both control and HTN(-)HFpEF, patients with HTN(+)HFpEF had increased LVEDP, left atrial volume, NT-proBNP, total, collagen-dependent and titin-dependent stiffness, insoluble collagen, increased titin phosphorylation on PEVK S11878(S26), reduced phosphorylation on N2B S4185(S469), and increased biomarkers of inflammation. Conclusions Hypertension in the absence of HFpEF, did not alter passive myocardial stiffness. Patients with HTN(+)HFpEF had a significant increase in passive myocardial stiffness; collagen-dependent and titin-dependent stiffness were increased. These data suggest that the development of HFpEF is dependent on changes in both collagen and titin homeostasis. PMID:25637629

  16. Advanced Glycation End Products in Extracellular Matrix Proteins Contribute to the Failure of Sensory Nerve Regeneration in Diabetes

    PubMed Central

    Duran-Jimenez, Beatriz; Dobler, Darin; Moffatt, Sarah; Rabbani, Naila; Streuli, Charles H.; Thornalley, Paul J.; Tomlinson, David R.; Gardiner, Natalie J.

    2009-01-01

    OBJECTIVE The goal of this study was to characterize glycation adducts formed in both in vivo extracellular matrix (ECM) proteins of endoneurium from streptozotocin (STZ)-induced diabetic rats and in vitro by glycation of laminin and fibronectin with methylglyoxal and glucose. We also investigated the impact of advanced glycation end product (AGE) residue content of ECM on neurite outgrowth from sensory neurons. RESEARCH DESIGN AND METHODS Glycation, oxidation, and nitration adducts of ECM proteins extracted from the endoneurium of control and STZ-induced diabetic rat sciatic nerve (3–24 weeks post-STZ) and of laminin and fibronectin that had been glycated using glucose or methylglyoxal were examined by liquid chromatography with tandem mass spectrometry. Methylglyoxal-glycated or unmodified ECM proteins were used as substrata for dissociated rat sensory neurons as in vitro models of regeneration. RESULTS STZ-induced diabetes produced a significant increase in early glycation Nε-fructosyl-lysine and AGE residue contents of endoneurial ECM. Glycation of laminin and fibronectin by methylglyoxal and glucose increased glycation adduct residue contents with methylglyoxal-derived hydroimidazolone and Nε-fructosyl-lysine, respectively, of greatest quantitative importance. Glycation of laminin caused a significant decrease in both neurotrophin-stimulated and preconditioned sensory neurite outgrowth. This decrease was prevented by aminoguanidine. Glycation of fibronectin also decreased preconditioned neurite outgrowth, which was prevented by aminoguanidine and nerve growth factor. CONCLUSIONS Early glycation and AGE residue content of endoneurial ECM proteins increase markedly in STZ-induced diabetes. Glycation of laminin and fibronectin causes a reduction in neurotrophin-stimulated neurite outgrowth and preconditioned neurite outgrowth. This may provide a mechanism for the failure of collateral sprouting and axonal regeneration in diabetic neuropathy. PMID:19720799

  17. Α-Dendrotoxin-sensitive Kv1 channels contribute to conduction failure of polymodal nociceptive C-fibers from rat coccygeal nerve.

    PubMed

    Wang, Xiu-Chao; Wang, Shan; Zhang, Ming; Gao, Fang; Yin, Chun; Li, Hao; Zhang, Ying; Hu, San-Jue; Duan, Jian-Hong

    2016-02-01

    It is known that some patients with diabetic neuropathy are usually accompanied by abnormal painful sensations. Evidence has accumulated that diabetic neuropathic pain is associated with the hyperexcitability of peripheral nociceptors. Previously, we demonstrated that reduced conduction failure of polymodal nociceptive C-fibers and enhanced voltage-dependent sodium currents of small dorsal root ganglion (DRG) neurons contribute to diabetic hyperalgesia. To further investigate whether and how potassium channels are involved in the conduction failure, α-dendrotoxin (α-DTX), a selective blocker of the low-threshold sustained Kv1 channel, was chosen to examine its functional capability in modulating the conduction properties of polymodal nociceptive C-fibers and the excitability of sensory neurons. We found that α-DTX reduced the conduction failure of C-fibers from coccygeal nerve in vivo accompanied by an increased initial conduction velocity but a decreased activity-dependent slowing of conduction velocity. In addition, the number of APs evoked by step currents was significantly enhanced after the treatment with α-DTX in small-diameter sensory neurons. Further study of the mechanism indicates α-DTX-sensitive K(+) current significantly reduced and the activation of this current in peak and steady state shifted to depolarization for diabetic neurons. Expression of Kv channel subunits Kv1.2 and Kv1.6 was downregulated in both small dorsal root ganglion neurons and peripheral C-fibers. Taken together, these results suggest that α-DTX-sensitive Kv1 channels might play an important role in regulating the conduction properties of polymodal nociceptive C-fibers and firing properties of sensory neurons.

  18. Des Moines.

    ERIC Educational Resources Information Center

    Gore, Deborah, Ed.

    1988-01-01

    This document, intended for elementary students, contains articles and activities designed to acquaint young people with the history of Des Moines, Iowa. The articles are short, and new or difficult words are highlighted and defined for young readers. "The Raccoon River Indian Agency" discusses the archeological exploration of the indian…

  19. Des Moines.

    ERIC Educational Resources Information Center

    Gore, Deborah, Ed.

    1988-01-01

    This document, intended for elementary students, contains articles and activities designed to acquaint young people with the history of Des Moines, Iowa. The articles are short, and new or difficult words are highlighted and defined for young readers. "The Raccoon River Indian Agency" discusses the archeological exploration of the indian…

  20. Les contributions de la psychologie cognitive a l'enseignement strategique des langues secondes au niveau universitaire (The Contributions of Cognitive Psychology to Strategic Second Language Instruction at the University Level).

    ERIC Educational Resources Information Center

    Besnard, Christine

    1995-01-01

    Contributions of the field of cognitive psychology to second language instruction are reviewed. It is proposed that these concepts can contribute not only to classroom language instruction, but also to methodology of language teacher education. (MSE)

  1. Les contributions de la psychologie cognitive a l'enseignement strategique des langues secondes au niveau universitaire (The Contributions of Cognitive Psychology to Strategic Second Language Instruction at the University Level).

    ERIC Educational Resources Information Center

    Besnard, Christine

    1995-01-01

    Contributions of the field of cognitive psychology to second language instruction are reviewed. It is proposed that these concepts can contribute not only to classroom language instruction, but also to methodology of language teacher education. (MSE)

  2. Failure diagnosis using discrete event models

    SciTech Connect

    Sampath, M.; Sengupta, R.; Lafortune, S.; Teneketzis, D.; Sinnamohideen, K.

    1994-12-31

    We propose a Discrete Event Systems (DES) approach to the failure diagnosis problem. We present a methodology for modeling physical systems in a DES framework. We discuss the notion of diagnosability and present the construction procedure of the diagnoser. Finally, we illustrate our approach using a Heating, Ventilation and Air Conditioning (HVAC) system.

  3. Global left atrial failure in heart failure.

    PubMed

    Triposkiadis, Filippos; Pieske, Burkert; Butler, Javed; Parissis, John; Giamouzis, Gregory; Skoularigis, John; Brutsaert, Dirk; Boudoulas, Harisios

    2016-11-01

    The left atrium plays an important role in the maintenance of cardiovascular and neurohumoral homeostasis in heart failure. However, with progressive left ventricular dysfunction, left atrial (LA) dilation and mechanical failure develop, which frequently culminate in atrial fibrillation. Moreover, LA mechanical failure is accompanied by LA endocrine failure [deficient atrial natriuretic peptide (ANP) processing-synthesis/development of ANP resistance) and LA regulatory failure (dominance of sympathetic nervous system excitatory mechanisms, excessive vasopressin release) contributing to neurohumoral overactivity, vasoconstriction, and volume overload (global LA failure). The purpose of the present review is to describe the characteristics and emphasize the clinical significance of global LA failure in patients with heart failure. © 2016 The Authors. European Journal of Heart Failure © 2016 European Society of Cardiology.

  4. Developmental delays consistent with cochlear hypothyroidism contribute to failure to develop hearing in mice lacking Slc26a4/pendrin expression

    PubMed Central

    Kim, Hyoung-Mi; Billings, Sara; Nakaya, Kazuhiro; Li, Xiangming; Singh, Ruchira; Sharlin, David S.; Forrest, Douglas; Marcus, Daniel C.; Fong, Peying

    2009-01-01

    Mutations of SLC26A4 cause an enlarged vestibular aqueduct, nonsyndromic deafness, and deafness as part of Pendred syndrome. SLC26A4 encodes pendrin, an anion exchanger located in the cochlea, thyroid, and kidney. The goal of the present study was to determine whether developmental delays, possibly mediated by systemic or local hypothyroidism, contribute to the failure to develop hearing in mice lacking Slc26a4 (Slc26a4−/−). We evaluated thyroid function by voltage and pH measurements, by array-assisted gene expression analysis, and by determination of plasma thyroxine levels. Cochlear development was evaluated for signs of hypothyroidism by microscopy, in situ hybridization, and quantitative RT-PCR. No differences in plasma thyroxine levels were found in Slc26a4−/− and sex-matched Slc26a4+/− littermates between postnatal day 5 (P5) and P90. In adult Slc26a4−/− mice, the transepithelial potential and the pH of thyroid follicles were reduced. No differences in the expression of genes that participate in thyroid hormone synthesis or ion transport were observed at P15, when plasma thyroxine levels peaked. Scala media of the cochlea was 10-fold enlarged, bulging into and thereby displacing fibrocytes, which express Dio2 to generate a cochlear thyroid hormone peak at P7. Cochlear development, including tunnel opening, arrival of efferent innervation at outer hair cells, endochondral and intramembraneous ossification, and developmental changes in the expression of Dio2, Dio3, and Tectb were delayed by 1–4 days. These data suggest that pendrin functions as a HCO3− transporter in the thyroid, that Slc26a4−/− mice are systemically euthyroid, and that delays in cochlear development, possibly due to local hypothyroidism, lead to the failure to develop hearing. PMID:19692489

  5. Numerical Investigation of Seismically Induced Rock Mass Fatigue as a Mechanism Contributing to the Progressive Failure of Deep-Seated Landslides

    NASA Astrophysics Data System (ADS)

    Gischig, Valentin; Preisig, Giona; Eberhardt, Erik

    2016-06-01

    The importance of earthquakes in triggering catastrophic failure of deep-seated landslides has long been recognized and is well documented in the literature. However, seismic waves do not only act as a trigger mechanism. They also contribute to the progressive failure of large rock slopes as a fatigue process that is highly efficient in deforming and damaging rock slopes. Given the typically long recurrence time and unpredictability of earthquakes, field-based investigations of co-seismic rock slope deformations are difficult. We present here a conceptual numerical study that demonstrates how repeated earthquake activity over time can destabilize a relatively strong rock slope by creating and propagating new fractures until the rock mass is sufficiently weakened to initiate catastrophic failure. Our results further show that the damage and displacement induced by a certain earthquake strongly depends on pre-existing damage. In fact, the damage history of the slope influences the earthquake-induced displacement as much as earthquake ground motion characteristics such as the peak ground acceleration. Because seismically induced fatigue is: (1) characterized by low repeat frequency, (2) represents a large amplitude damage event, and (3) weakens the entire rock mass, it differs from other fatigue processes. Hydro-mechanical cycles, for instance, occur at higher repeat frequencies (i.e., annual cycles), lower amplitude, and only affect limited parts of the rock mass. Thus, we also compare seismically induced fatigue to seasonal hydro-mechanical fatigue. While earthquakes can progressively weaken even a strong, competent rock mass, hydro-mechanical fatigue requires a higher degree of pre-existing damage to be effective. We conclude that displacement rates induced by hydro-mechanical cycling are indicative of the degree of pre-existing damage in the rock mass. Another indicator of pre-existing damage is the seismic amplification pattern of a slope; frequency

  6. Heart Failure

    MedlinePlus

    ... version of this page please turn Javascript on. Heart Failure What is Heart Failure? In heart failure, the heart cannot pump enough ... failure often experience tiredness and shortness of breath. Heart Failure is Serious Heart failure is a serious and ...

  7. Technical Evaluation Report on the Guidance and Control Panel 53rd Symposium on Air Vehicle Mission Control and Management (La Gestion et le Controle des Missions des Vehicules Aeriens)

    DTIC Science & Technology

    1992-07-01

    d’importance dans le guidage et le pilotage des vehicules aeriens. Les developpements dans ce domaine representent des contributions d’une importance...d’un vehicule non-pilots. fonctionner en mode automatique. Les communications techniques ont examine les realisations et les tendances actuelles dans...le domaine de la gestion des missions des vehicules aeriens, presente !’tat de I’art et propos, des solutions technologiques pour la conception des

  8. Physiological dead space and arterial carbon dioxide contributions to exercise ventilatory inefficiency in patients with reduced or preserved ejection fraction heart failure.

    PubMed

    Van Iterson, Erik H; Johnson, Bruce D; Borlaug, Barry A; Olson, Thomas P

    2017-10-08

    Patients with heart failure (HF) with reduced (HFrEF) or preserved (HFpEF) ejection fraction demonstrate an increased ventilatory equivalent for carbon dioxide (V̇E /V̇CO2 ) slope. The physiological correlates of the V̇E /V̇CO2 slope remain unclear in the two HF phenotypes. We hypothesized that changes in the physiological dead space to tidal volume ratio (VD /VT ) and arterial CO2 tension (PaCO2 ) differentially contribute to the V̇E /V̇CO2 slope in HFrEF vs. HFpEF. Adults with HFrEF (n = 32) and HFpEF (n = 27) [mean ± standard deviation (SD) left ventricular ejection fraction: 22 ± 7% and 61 ± 9%, respectively; mean ± SD body mass index: 28 ± 4 kg/m(2) and 33 ± 6 kg/m(2) , respectively; P < 0.01] performed cardiopulmonary exercise testing with breath-by-breath ventilation and gas exchange measurements. PaCO2 was measured via radial arterial catheterization. We calculated the V̇E /V̇CO2 slope via linear regression, and VD /VT  = 1 - [(863 × V̇CO2 )/(V̇E  × PaCO2 )]. Resting VD /VT (0.48 ± 0.08 vs. 0.41 ± 0.11; P = 0.04), but not PaCO2 (38 ± 5 mmHg vs. 40 ± 3 mmHg; P = 0.21) differed between HFrEF and HFpEF. Peak exercise VD /VT (0.39 ± 0.08 vs. 0.32 ± 0.12; P = 0.02) and PaCO2 (33 ± 6 mmHg vs. 38 ± 4 mmHg; P < 0.01) differed between HFrEF and HFpEF. The V̇E /V̇CO2 slope was higher in HFrEF compared with HFpEF (44 ± 11 vs. 35 ± 8; P < 0.01). Variance associated with the V̇E /V̇CO2 slope in HFrEF and HFpEF was explained by peak exercise VD /VT (R(2)  = 0.30 and R(2)  = 0.50, respectively) and PaCO2 (R(2)  = 0.64 and R(2)  = 0.28, respectively), but the relative contributions of each differed (all P < 0.01). Relationships between the V̇E /V̇CO2 slope and both VD /VT and PaCO2 are robust, but differ between HFpEF and HFrEF. Increasing V̇E /V̇CO2 slope appears to be strongly explained by

  9. Contributing factors to the failure of an unusually large landslide triggered by the 2014 Ludian, Yunnan, China, Ms = 6.5 earthquake

    NASA Astrophysics Data System (ADS)

    Chang, Z. F.; Chen, X. L.; An, X. W.; Cui, J. W.

    2016-02-01

    The 3 August 2014 Ludian, China, Ms = 6.5 earthquake caused many large landslides. The biggest occurred at Hongshiyan near the epicenter, had a volume of 1.0 × 107 m3 and dammed the Niulanjiang River, creating a large lake. Post-event field investigations yielded detailed data on the following aspects: rock structure of the landslide, the local lithology and geometry of the area around the landslide dam and composition and grain sizes of the debris avalanche. Based on these data, this work analyzes the geology and topography of the Hongshiyan area, and explores reasons for the occurrence of an unusually large landslide at this location. Our analysis suggests the following conditions are responsible for this catastrophic event. (1) Due to recent crustal deformation, intense incision on the river increased topographic relief with steep slopes and scarps. (2) Combined structures, including unloading fissures, high-angle joints and low-angle beds along the river, as well as an upper-strong and lower-weak interlayer structure on the slope, especially the existence of weak layers in the slope, are important factors that contribute to this large failure. (3) Hongshiyan lies near an active fault, where intense crustal deformation has resulted in rock fractures and weathering, and frequent earthquakes may progressively reduce the strength of the slope. (4) During the Ms = 6.5 earthquake, the terrain and site conditions led to abnormally strong ground shaking. The combined impacts of these factors triggered a very large landslide during a moderate-sized earthquake.

  10. ERK1/2 MAPK signaling in hypothalamic paraventricular nucleus contributes to sympathetic excitation in rats with heart failure after myocardial infarction.

    PubMed

    Yu, Yang; Wei, Shun-Guang; Zhang, Zhi-Hua; Weiss, Robert M; Felder, Robert B

    2016-03-15

    Brain MAPK signaling pathways are activated in heart failure (HF) induced by myocardial infarction and contribute to augmented sympathetic nerve activity. We tested whether decreasing ERK1/2 (also known as p44/42 MAPK) signaling in the hypothalamic paraventricular nucleus (PVN), a forebrain source of presympathetic neurons, would reduce the upregulation of sympathoexcitatory mediators in the PVN and augmented sympathetic nerve activity in rats with HF. Sprague-Dawley rats underwent left anterior descending coronary artery ligation to induce HF, with left ventricular dysfunction confirmed by echocardiography. One week after coronary artery ligation or sham operation, small interfering (si)RNAs targeting ERK1/2 or a nontargeting control siRNA was microinjected bilaterally into the PVN. Experiments were conducted 5-7 days later. Confocal images revealed reduced phosphorylated ERK1/2 immunofluorescence in the PVN of HF rats treated with ERK1/2 siRNAs compared with HF rats treated with control siRNA. Western blot analysis confirmed significant reductions in both total and phosphorylated ERK1/2 in the PVN of HF rats treated with ERK1/2 siRNAs along with reduced expression of renin-angiotensin system components and inflammatory mediators. HF rats treated with ERK1/2 siRNAs also had reduced PVN neuronal excitation (fewer Fos-related antigen-like-immunoreactive neurons), lower plasma norepinephrine levels, and improved peripheral manifestations of HF compared with HF rats treated with control siRNAs. These results demonstrate that ERK1/2 signaling in the PVN plays a pivotal role in mediating sympathetic drive in HF induced by myocardial infarction and may be a novel target for therapeutic intervention. Copyright © 2016 the American Physiological Society.

  11. ERK1/2 MAPK signaling in hypothalamic paraventricular nucleus contributes to sympathetic excitation in rats with heart failure after myocardial infarction

    PubMed Central

    Yu, Yang; Wei, Shun-Guang; Zhang, Zhi-Hua; Weiss, Robert M.

    2016-01-01

    Brain MAPK signaling pathways are activated in heart failure (HF) induced by myocardial infarction and contribute to augmented sympathetic nerve activity. We tested whether decreasing ERK1/2 (also known as p44/42 MAPK) signaling in the hypothalamic paraventricular nucleus (PVN), a forebrain source of presympathetic neurons, would reduce the upregulation of sympathoexcitatory mediators in the PVN and augmented sympathetic nerve activity in rats with HF. Sprague-Dawley rats underwent left anterior descending coronary artery ligation to induce HF, with left ventricular dysfunction confirmed by echocardiography. One week after coronary artery ligation or sham operation, small interfering (si)RNAs targeting ERK1/2 or a nontargeting control siRNA was microinjected bilaterally into the PVN. Experiments were conducted 5–7 days later. Confocal images revealed reduced phosphorylated ERK1/2 immunofluorescence in the PVN of HF rats treated with ERK1/2 siRNAs compared with HF rats treated with control siRNA. Western blot analysis confirmed significant reductions in both total and phosphorylated ERK1/2 in the PVN of HF rats treated with ERK1/2 siRNAs along with reduced expression of renin-angiotensin system components and inflammatory mediators. HF rats treated with ERK1/2 siRNAs also had reduced PVN neuronal excitation (fewer Fos-related antigen-like-immunoreactive neurons), lower plasma norepinephrine levels, and improved peripheral manifestations of HF compared with HF rats treated with control siRNAs. These results demonstrate that ERK1/2 signaling in the PVN plays a pivotal role in mediating sympathetic drive in HF induced by myocardial infarction and may be a novel target for therapeutic intervention. PMID:26801309

  12. Inducible nitric oxide synthase-derived superoxide contributes to hypereactivity in small mesenteric arteries from a rat model of chronic heart failure

    PubMed Central

    Miller, Alyson A; Megson, Ian L; Gray, Gillian A

    2000-01-01

    The aims of this study were to (a) determine whether inducible nitric oxide synthase (iNOS) is expressed in small mesenteric arteries from rats with chronic heart failure (CHF), (b) investigate the functional significance of this potential source of nitric oxide (NO) on vascular responsiveness and (c) investigate the role that superoxide plays in modulating vascular function in these arteries. CHF was induced in male Wistar rats by coronary artery ligation (CAL). In sham-operated rats the ligature was not tied but pulled under the artery. Six weeks after surgery CAL rats had left ventricular (LV) infarctions and elevated LV end-diastolic pressures. Immunoreactive iNOS was found in endothelial cells, vascular smooth muscle cells and in the adventitia of small mesenteric arteries from CAL rats but not those from sham-operated rats. Third order mesenteric arteries (300–350 μm) were mounted in a small vessel pressure myograph. Endothelium-intact arteries from CAL rats were more responsive to phenylephrine (PE) than arteries from sham-operated rats (pD2 value, CAL, 6.2±0.1; sham-operated, 5.9±0.1, P<0.05). Both the selective iNOS inhibitor, N-(3-(Aminomethyl) benzyl) acetamidine dihydrochloride (1400W; 10−6 M) and the superoxide dismutase mimetic, Mn [III] tetrakis [1-methyl-4-pyridyl] porphyrin, (MnTMPyP; 10−4 M) reversed the hyperesponsiveness (pD2 values, 1400W, 5.9±0.1; MnTMPyP, 5.81±0.1, P<0.05). The NOS substrate, L-arginine (10−3 M), reduced responsiveness of endothelium-denuded small mesenteric arteries from CAL rats (P<0.01). None of these drugs altered responses to PE in arteries from sham-operated rats. In summary, this study demonstrates that iNOS is expressed in mesenteric arteries from rats with CHF. However, instead of generating large quantities of NO, iNOS appears to be generating superoxide, perhaps because of a deficiency in its substrate, L-arginine. Increased superoxide generation from iNOS contributes to the hyperesponsive

  13. 26 CFR 31.6652(c)-1 - Failure of employee to report tips for purposes of the Federal Insurance Contributions Act.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... imposed by section 3101 with respect to the amount of tips which he so failed to report, an amount equal... failed to report will not be required if it is established to the satisfaction of the district director... 26 Internal Revenue 15 2011-04-01 2011-04-01 false Failure of employee to report tips for purposes...

  14. Failure Assessment

    NASA Technical Reports Server (NTRS)

    Lutz, Robyn; Nikora, Allen

    2005-01-01

    Three questions to which software developers want accurate, precise answers are "How can the software system fail?", "mat bad things will happen if the software fails?t', and "How many failures will the software experience?". Numerous techniques have been devised to answer these questions; three of the best known are: 1) Software Fault Tree Analysis (SFTA) 2) Software Failure Modes, Effects, and Criticality Analysis (SFMECA 3) Software Fault/Failure Modeling. SFTA and SFMECA have been successfully used to analyze the flight software for a number of robotic planetary exploration missions, including Galileo, Cassini, and Deep Space 1. Given the increasing interest in reusing software components from mission to mission, one of us has developed techniques for reusing the corresponding portions of the SFTA and SFMECA, reducing the effort required to conduct these analyses. SFTA has also been shown to be effective in analyzing the security aspects of software systems; intrusion mechanisms and effects can easily be modeled using these techniques. The Bi- Directional Safety Analysis (BDSA) method combines a forward search (similar to SFMECA) from potential failure modes to their effects, with a backward search (similar to SFTA) from feasible hazards to the contributing causes of each hazard. BDSA offers an efficient way to identify latent failures. Recent work has extended BDSA to product-line applications such as flight-instrumentation displays and developed tool support for the reuse of the failure-analysis artifacts within a product line. BDSA has also been streamlined to support those projects having tight cost and/or schedule constraints for their failure analysis efforts. We discuss lessons learned from practice, describe available tools, and identi@ some future directions for the topic. A substantial amount of research has been devoted to estimating the number of failures that a software system will experience during test and operations, as well as the number of

  15. Some risk factors for reproductive failures and contribution of Toxoplasma gondii infection in sheep and goats of Central Ethiopia: a cross-sectional study.

    PubMed

    Gebremedhin, Endrias Zewdu; Agonafir, Abebe; Tessema, Tesfaye Sisay; Tilahun, Getachew; Medhin, Girmay; Vitale, Maria; Di Marco, Vincenzo

    2013-12-01

    Reproductive failure has a negative impact on animal production, health and welfare and ultimately rural economies. In Ethiopia, the factors affecting small ruminant reproductive efficiency are inadequately investigated. A cross-sectional survey was done from November, 2010 to May, 2011 to investigate risk factors of reproductive failures including Toxoplasma gondii infection. Analysis of 1372 sera (787 sheep and 585 goats) from 409 flocks using ELISA showed high flock (59.7%) and animal (31.8%) level T. gondii seroprevalence. An overall 24.9% (341/1372) annual abortion rate (19.6% in sheep and 32.0% in goats) was recorded. Animal level T. gondii seroprevalence was significantly associated with abortion in Ambo and Ada'a-Liben districts (Odds ratio [OR] = 2.31, 95% confidence interval [CI]: 1.42, 3.76; P = 0.001). Questionnaire survey on 199 households of Ambo, Ada'a-Liben and Fentale districts revealed high flock level abortion (57.5%), still birth (28.9%) and neonatal losses (47.9%), which are significantly different between study districts (P<0.001). Multivariable logistic regression model showed that species (goat), large flock size, pastoral and agro-pastoral production systems, drinking water from river and stagnant water bodies, grazing/browsing in plain land and extensive management were significant predictors of flock level reproductive failures. In the final Zero inflated Poisson regression model number of abortions was significantly higher in goat than in sheep flocks (Incidence risk ratio [IRR] = 1.42, 95% CI: 1.08, 1.87; P = 0.012). It is also significantly higher in pastoral (IRR = 1.81, 95% CI: 1.16, 2.83; P = 0.008) and agro-pastoral production systems (IRR = 1.94, 95% CI: 1.32, 2.86; P = 0.001) than in sedentary production system. Prevention of toxoplasmosis, improved husbandry practices and further epidemiological studies to identify causes of reproductive failures are recommended.

  16. The contribution of reactive oxygen species and p38 mitogen-activated protein kinase to myofilament oxidation and progression of heart failure in rabbits.

    PubMed

    Heusch, P; Canton, M; Aker, S; van de Sand, A; Konietzka, I; Rassaf, T; Menazza, S; Brodde, O E; Di Lisa, F; Heusch, G; Schulz, R

    2010-07-01

    The formation of reactive oxygen species (ROS) is increased in heart failure (HF). However, the causal and mechanistic relationship of ROS formation with contractile dysfunction is not clear in detail. Therefore, ROS formation, myofibrillar protein oxidation and p38 MAP kinase activation were related to contractile function in failing rabbit hearts. Three weeks of rapid left ventricular (LV) pacing reduced LV shortening fraction (SF, echocardiography) from 32 +/- 1% to 13 +/- 1%. ROS formation, as assessed by dihydroethidine staining, increased by 36 +/- 8% and was associated with increased tropomyosin oxidation, as reflected by dimer formation (dimer to monomer ratio increased 2.28 +/- 0.66-fold in HF vs. sham, P < 0.05). Apoptosis (TdT-mediated dUTP nick end labelling staining) increased more than 12-fold after 3 weeks of pacing when a significant increase in the phosphorylation of p38 MAP kinase and HSP27 was detected (Western blotting). Vitamins C and E abolished the increases in ROS formation and tropomyosin oxidation along with an improvement of LVSF (19 +/- 1%, P < 0.05 vs. untreated HF) and prevention of apoptosis, but without modifying p38 MAP kinase activation. Inhibition of p38 MAP kinase by SB281832 counteracted ROS formation, tropomyosin oxidation and contractile failure, without affecting apoptosis. Thus, p38 MAP kinase activation appears to be upstream rather than downstream of ROS, which impacts on LV function through myofibrillar oxidation. p38 MAP kinase inhibition is a potential target to prevent or treat HF.

  17. The contribution of reactive oxygen species and p38 mitogen-activated protein kinase to myofilament oxidation and progression of heart failure in rabbits

    PubMed Central

    Heusch, P; Canton, M; Aker, S; van de Sand, A; Konietzka, I; Rassaf, T; Menazza, S; Brodde, OE; Di Lisa, F; Heusch, G; Schulz, R

    2010-01-01

    Background and purpose: The formation of reactive oxygen species (ROS) is increased in heart failure (HF). However, the causal and mechanistic relationship of ROS formation with contractile dysfunction is not clear in detail. Therefore, ROS formation, myofibrillar protein oxidation and p38 MAP kinase activation were related to contractile function in failing rabbit hearts. Experimental approach and key results: Three weeks of rapid left ventricular (LV) pacing reduced LV shortening fraction (SF, echocardiography) from 32 ± 1% to 13 ± 1%. ROS formation, as assessed by dihydroethidine staining, increased by 36 ± 8% and was associated with increased tropomyosin oxidation, as reflected by dimer formation (dimer to monomer ratio increased 2.28 ± 0.66-fold in HF vs. sham, P < 0.05). Apoptosis (TdT-mediated dUTP nick end labelling staining) increased more than 12-fold after 3 weeks of pacing when a significant increase in the phosphorylation of p38 MAP kinase and HSP27 was detected (Western blotting). Vitamins C and E abolished the increases in ROS formation and tropomyosin oxidation along with an improvement of LVSF (19 ± 1%, P < 0.05 vs. untreated HF) and prevention of apoptosis, but without modifying p38 MAP kinase activation. Inhibition of p38 MAP kinase by SB281832 counteracted ROS formation, tropomyosin oxidation and contractile failure, without affecting apoptosis. Conclusions and implications: Thus, p38 MAP kinase activation appears to be upstream rather than downstream of ROS, which impacts on LV function through myofibrillar oxidation. p38 MAP kinase inhibition is a potential target to prevent or treat HF. PMID:20590631

  18. Loss of MeCP2 Causes Urological Dysfunction and Contributes to Death by Kidney Failure in Mouse Models of Rett Syndrome

    PubMed Central

    Ward, Christopher S.; Huang, Teng-Wei; Herrera, José A.; Samaco, Rodney C.; Pitcher, Meagan R.; Herron, Alan; Skinner, Steven A.; Kaufmann, Walter E.; Glaze, Daniel G.; Percy, Alan K.; Neul, Jeffrey L.

    2016-01-01

    Rett Syndrome (RTT) is a neurodevelopmental disorder characterized by loss of acquired skills during development, autonomic dysfunction, and an increased risk for premature lethality. Clinical experience identified a subset of individuals with RTT that present with urological dysfunction including individuals with frequent urinary tract infections, kidney stones, and urine retention requiring frequent catheterization for bladder voiding. To determine if urologic dysfunction is a feature of RTT, we queried the Rett Syndrome Natural History Study, a repository of clinical data from over 1000 individuals with RTT and found multiple instances of urological dysfunction. We then evaluated urological function in a mouse model of RTT and found an abnormal pattern of micturition. Both male and female mice possessing Mecp2 mutations show a decrease in urine output per micturition event. Furthermore, we identified signs of kidney failure secondary to urethral obstruction. Although genetic strain background significantly affects both survival and penetrance of the urethral obstruction phenotype, survival and penetrance of urethral obstruction do not directly correlate. We have identified an additional phenotype caused by loss of MeCP2, urological dysfunction. Furthermore, we urge caution in the interpretation of survival data as an endpoint in preclinical studies, especially where causes of mortality are poorly characterized. PMID:27828991

  19. Acute care costs of patients admitted for management of chronic obstructive pulmonary disease exacerbations: contribution of disease severity, infection and chronic heart failure.

    PubMed

    Hutchinson, A; Brand, C; Irving, L; Roberts, C; Thompson, P; Campbell, D

    2010-05-01

    In 2003, chronic obstructive pulmonary disease (COPD) accounted for 46% of the burden of chronic respiratory disease in the Australian community. In the 65-74-year-old age group, COPD was the sixth leading cause of disability for men and the seventh for women. To measure the influence of disease severity, COPD phenotype and comorbidities on acute health service utilization and direct acute care costs in patients admitted with COPD. Prospective cohort study of 80 patients admitted to the Royal Melbourne Hospital in 2001-2002 for an exacerbation of COPD. Patients were followed for 12 months and data were collected on acute care utilization. Direct hospital costs were derived using Transition II, an activity-based costing system. Individual patient costs were then modelled to ascertain which patient factors influenced total direct hospital costs. Direct costs were calculated for 225 episodes of care, the median cost per admission was AU$3124 (interquartile range $1393 to $5045). The median direct cost of acute care management per patient per year was AU$7273 (interquartile range $3957 to $14 448). In a multivariate analysis using linear regression modelling, factors predictive of higher annual costs were increasing age (P= 0.041), use of domiciliary oxygen (P= 0.008) and the presence of chronic heart failure (P= 0.006). This model has identified a number of patient factors that predict higher acute care costs and awareness of these can be used for service planning to meet the needs of patients admitted with COPD.

  20. Loss of MeCP2 Causes Urological Dysfunction and Contributes to Death by Kidney Failure in Mouse Models of Rett Syndrome.

    PubMed

    Ward, Christopher S; Huang, Teng-Wei; Herrera, José A; Samaco, Rodney C; Pitcher, Meagan R; Herron, Alan; Skinner, Steven A; Kaufmann, Walter E; Glaze, Daniel G; Percy, Alan K; Neul, Jeffrey L

    2016-01-01

    Rett Syndrome (RTT) is a neurodevelopmental disorder characterized by loss of acquired skills during development, autonomic dysfunction, and an increased risk for premature lethality. Clinical experience identified a subset of individuals with RTT that present with urological dysfunction including individuals with frequent urinary tract infections, kidney stones, and urine retention requiring frequent catheterization for bladder voiding. To determine if urologic dysfunction is a feature of RTT, we queried the Rett Syndrome Natural History Study, a repository of clinical data from over 1000 individuals with RTT and found multiple instances of urological dysfunction. We then evaluated urological function in a mouse model of RTT and found an abnormal pattern of micturition. Both male and female mice possessing Mecp2 mutations show a decrease in urine output per micturition event. Furthermore, we identified signs of kidney failure secondary to urethral obstruction. Although genetic strain background significantly affects both survival and penetrance of the urethral obstruction phenotype, survival and penetrance of urethral obstruction do not directly correlate. We have identified an additional phenotype caused by loss of MeCP2, urological dysfunction. Furthermore, we urge caution in the interpretation of survival data as an endpoint in preclinical studies, especially where causes of mortality are poorly characterized.

  1. Diffusion incohérente des neutrons : modèles analytiques pour la dynamique interne des protéines

    NASA Astrophysics Data System (ADS)

    Bicout, D. J.

    2005-11-01

    La dynamique interne des protéines joue un rôle central dans la stabilité, la fonction et l'activité biologique de ces biomolécules. Il est maintenant établi que les fluctuations d'états conformationnels des protéines influencent fortement la plupart des réactions biochimiques et s'accompagnent d'une augmentation brutale des déplacements carrés moyens des atomes au dessus de la température de la transition dynamique. Dans cette contribution, nous présentons une revue critique de quelques modèles théoriques couramment utilisés dans la littérature pour l'analyse des mouvements internes des protéines et la description de la transition dynamique.

  2. Failure to thrive.

    PubMed

    Krugman, Scott D; Dubowitz, Howard

    2003-09-01

    Failure to thrive is a condition commonly seen by primary care physicians. Prompt diagnosis and intervention are important for preventing malnutrition and developmental sequelae. Medical and social factors often contribute to failure to thrive. Either extreme of parental attention (neglect or hypervigilance) can lead to failure to thrive. About 25 percent of normal infants will shift to a lower growth percentile in the first two years of life and then follow that percentile; this should not be diagnosed as failure to thrive. Infants with Down syndrome, intrauterine growth retardation, or premature birth follow different growth patterns than normal infants. Many infants with failure to thrive are not identified unless careful attention is paid to plotting growth parameters at routine checkups. A thorough history is the best guide to establishing the etiology of the failure to thrive and directing further evaluation and management. All children with failure to thrive need additional calories for catch-up growth (typically 150 percent of the caloric requirement for their expected, not actual, weight). Few need laboratory evaluation. Hospitalization is rarely required and is indicated only for severe failure to thrive and for those whose safety is a concern. A multidisciplinary approach is recommended when failure to thrive persists despite intervention or when it is severe.

  3. Contribution of the long-term care insurance certificate for predicting 1-year all-cause readmission compared with validated risk scores in elderly patients with heart failure.

    PubMed

    Takahashi, Kayo; Saito, Makoto; Inaba, Shinji; Morofuji, Toru; Aisu, Hiroe; Sumimoto, Takumi; Ogimoto, Akiyoshi; Ikeda, Shuntaro; Higaki, Jitsuo

    2016-01-01

    Readmission is a common and serious problem associated with heart failure (HF). Unfortunately, conventional risk models have limited predictive value for predicting readmission. The recipients of long-term care insurance (LTCI) are frail and have mental and physical impairments. We hypothesised that adjustment of the conventional risk score with an LTCI certificate enables a more accurate appreciation of readmission for HF. We investigated 452 patients with HF who were followed up for 1 year to determine all-cause readmission. We obtained their clinical and socioeconomic data, including LTCI. The three clinical risk scores used in our evaluation were Keenan (2008), Krumholz (2000) and Charlson (1994). We used net reclassification improvement (NRI) to assess the incremental benefit. Patients with LTCI were significantly older, and had a higher prevalence of cerebrovascular disease and dementia than those without LTCI. One-year all-cause readmission (n=193, 43%) was significantly associated with all risk scores, receiving LTCI and the category of LTCI. Receiving LTCI was associated with readmission independent of all risk scores (HR, 1.59 to 1.63; all p<0.01). Adding LTCI to all risk scores led to a significantly improved reclassification, which was observed in the subgroup of patients with HF with preserved ejection fraction (≥50%) but not in the subgroup with reduced ejection fraction (<50%). Possession of an LTCI certificate was independently associated with 1-year all-cause readmission after adjusting for validated clinical risk scores in patients with HF. Adding LTCI status significantly improved the model performance for readmission risk, particularly in patients with HF and preserved ejection fraction.

  4. Contribution of the long-term care insurance certificate for predicting 1-year all-cause readmission compared with validated risk scores in elderly patients with heart failure

    PubMed Central

    Takahashi, Kayo; Saito, Makoto; Inaba, Shinji; Morofuji, Toru; Aisu, Hiroe; Sumimoto, Takumi; Ogimoto, Akiyoshi; Ikeda, Shuntaro; Higaki, Jitsuo

    2016-01-01

    Objectives Readmission is a common and serious problem associated with heart failure (HF). Unfortunately, conventional risk models have limited predictive value for predicting readmission. The recipients of long-term care insurance (LTCI) are frail and have mental and physical impairments. We hypothesised that adjustment of the conventional risk score with an LTCI certificate enables a more accurate appreciation of readmission for HF. Methods We investigated 452 patients with HF who were followed up for 1 year to determine all-cause readmission. We obtained their clinical and socioeconomic data, including LTCI. The three clinical risk scores used in our evaluation were Keenan (2008), Krumholz (2000) and Charlson (1994). We used net reclassification improvement (NRI) to assess the incremental benefit. Results Patients with LTCI were significantly older, and had a higher prevalence of cerebrovascular disease and dementia than those without LTCI. One-year all-cause readmission (n=193, 43%) was significantly associated with all risk scores, receiving LTCI and the category of LTCI. Receiving LTCI was associated with readmission independent of all risk scores (HR, 1.59 to 1.63; all p<0.01). Adding LTCI to all risk scores led to a significantly improved reclassification, which was observed in the subgroup of patients with HF with preserved ejection fraction (≥50%) but not in the subgroup with reduced ejection fraction (<50%). Conclusions Possession of an LTCI certificate was independently associated with 1-year all-cause readmission after adjusting for validated clinical risk scores in patients with HF. Adding LTCI status significantly improved the model performance for readmission risk, particularly in patients with HF and preserved ejection fraction. PMID:27933194

  5. Generic Safety Issue (GSI) 171 -- Engineered Safety Feature (ESF) failure from a loop subsequent to LOCA: Assessment of plant vulnerability and CDF contributions

    SciTech Connect

    Martinez-Guridi, G.; Samanta, P.; Chu, L.; Yang, J.

    1998-03-01

    Generic Safety Issue 171 (GSI-171), Engineered Safety Feature (ESF) from a Loss Of Offsite Power (LOOP) subsequent to a Loss Of Coolant Accident (LOCA), deals with an accident sequence in which a LOCA is followed by a LOOP. This issue was later broadened to include a LOOP followed by a LOCA. Plants are designed to handle a simultaneous LOCA and LOOP. In this paper, the authors address the unique issues that are involved i LOCA with delayed LOOP (LOCA/LOOP) and LOOP with delayed LOCA (LOOP/LOCA) accident sequences. LOCA/LOOP accidents are analyzed further by developing event-tree/fault-tree models to quantify their contributions to core-damage frequency (CDF) in a pressurized water reactor and a boiling water reactor (PWR and a BWR). Engineering evaluation and judgments are used during quantification to estimate the unique conditions that arise in a LOCA/LOOP accident. The results show that the CDF contribution of such an accident can be a dominant contributor to plant risk, although BWRs are less vulnerable than PWRs.

  6. Gait failure.

    PubMed

    Sudarsky, L

    1987-11-01

    Gait failure is a common presentation in the Emergency Department, and one that may herald an acute neurologic episode. This article reviews the mechanisms of gait failure, some of their causes, and the appropriate examination techniques for determining possible diagnoses.

  7. Respiratory Failure

    MedlinePlus

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can' ...

  8. Des ballons pour demain

    NASA Astrophysics Data System (ADS)

    Régipa, R.

    A partir d'une théorie sur la détermination des formes et des contraintes globales d'un ballon de révolution, ou s'en rapprochant, une nouvelle famille de ballons a été définie. Les ballons actuels, dits de ``forme naturelle'', sont calculés en général pour une tension circonférencielle nulle. Ainsi, pour une mission donnée, la tension longitudinale et la forme de l'enveloppe sont strictement imposées. Les ballons de la nouvelle génération sont globalement cylindriques et leurs pôles sont réunis par un câble axial, chargé de transmettre une partie des efforts depuis le crochet (pôle inférieur), directement au pôle supérieur. De plus, la zone latérale cylindrique est soumise à un faible champ de tensions circonférencielles. Ainsi, deux paramètres permettent de faire évoluer la distribution des tensions et la forme de l'enveloppe: - la tension du câble de liaison entre pôles (ou la longueur de ce câble) - la tension circonférencielle moyenne désirée (ou le rayon du ballon). On peut donc calculer et réaliser: - soit des ballons de forme adaptée, comme les ballons à fond plat pour le bon fonctionnement des montgolfières infrarouge (projet MIR); - soit des ballons optimisés pour une bonne répartition des contraintes et une meilleure utilisation des matériaux d'enveloppe, pour l'ensemble des programmes stratosphériques. Il s'ensuit une économie sensible des coûts de fabrication, une fiabilité accrue du fonctionnement de ces ballons et une rendement opérationnel bien supérieur, permettant entre autres, d'envisager des vols à très haute altitude en matériaux très légers.

  9. Heart Failure

    MedlinePlus

    Heart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Heart failure does not mean that your heart has stopped ... Tiredness and shortness of breath Common causes of heart failure are coronary artery disease, high blood pressure and ...

  10. The intramuscular contribution to the slow oxygen uptake kinetics during exercise in chronic heart failure is related to the severity of the condition

    PubMed Central

    Bowen, T. Scott; Cannon, Daniel T.; Murgatroyd, Scott R.; Birch, Karen M.; Witte, Klaus K.

    2012-01-01

    The mechanism for slow pulmonary O2 uptake (V̇o2) kinetics in patients with chronic heart failure (CHF) is unclear but may be due to limitations in the intramuscular control of O2 utilization or O2 delivery. Recent evidence of a transient overshoot in microvascular deoxygenation supports the latter. Prior (or warm-up) exercise can increase O2 delivery in healthy individuals. We therefore aimed to determine whether prior exercise could increase muscle oxygenation and speed V̇o2 kinetics during exercise in CHF. Fifteen men with CHF (New York Heart Association I–III) due to left ventricular systolic dysfunction performed two 6-min moderate-intensity exercise transitions (bouts 1 and 2, separated by 6 min of rest) from rest to 90% of lactate threshold on a cycle ergometer. V̇o2 was measured using a turbine and a mass spectrometer, and muscle tissue oxygenation index (TOI) was determined by near-infrared spectroscopy. Prior exercise increased resting TOI by 5.3 ± 2.4% (P = 0.001), attenuated the deoxygenation overshoot (−3.9 ± 3.6 vs. −2.0 ± 1.4%, P = 0.011), and speeded the V̇o2 time constant (τV̇o2; 49 ± 19 vs. 41 ± 16 s, P = 0.003). Resting TOI was correlated to τV̇o2 before (R2 = 0.51, P = 0.014) and after (R2 = 0.36, P = 0.051) warm-up exercise. However, the mean response time of TOI was speeded between bouts in half of the patients (26 ± 8 vs. 20 ± 8 s) and slowed in the remainder (32 ± 11 vs. 44 ± 16 s), the latter group having worse New York Heart Association scores (P = 0.042) and slower V̇o2 kinetics (P = 0.001). These data indicate that prior moderate-intensity exercise improves muscle oxygenation and speeds V̇o2 kinetics in CHF. The most severely limited patients, however, appear to have an intramuscular pathology that limits V̇o2 kinetics during moderate exercise. PMID:22033530

  11. Superinfection with drug-resistant HIV is rare and does not contribute substantially to therapy failure in a large European cohort

    PubMed Central

    2013-01-01

    Background Superinfection with drug resistant HIV strains could potentially contribute to compromised therapy in patients initially infected with drug-sensitive virus and receiving antiretroviral therapy. To investigate the importance of this potential route to drug resistance, we developed a bioinformatics pipeline to detect superinfection from routinely collected genotyping data, and assessed whether superinfection contributed to increased drug resistance in a large European cohort of viremic, drug treated patients. Methods We used sequence data from routine genotypic tests spanning the protease and partial reverse transcriptase regions in the Virolab and EuResist databases that collated data from five European countries. Superinfection was indicated when sequences of a patient failed to cluster together in phylogenetic trees constructed with selected sets of control sequences. A subset of the indicated cases was validated by re-sequencing pol and env regions from the original samples. Results 4425 patients had at least two sequences in the database, with a total of 13816 distinct sequence entries (of which 86% belonged to subtype B). We identified 107 patients with phylogenetic evidence for superinfection. In 14 of these cases, we analyzed newly amplified sequences from the original samples for validation purposes: only 2 cases were verified as superinfections in the repeated analyses, the other 12 cases turned out to involve sample or sequence misidentification. Resistance to drugs used at the time of strain replacement did not change in these two patients. A third case could not be validated by re-sequencing, but was supported as superinfection by an intermediate sequence with high degenerate base pair count within the time frame of strain switching. Drug resistance increased in this single patient. Conclusions Routine genotyping data are informative for the detection of HIV superinfection; however, most cases of non-monophyletic clustering in patient

  12. Paternité des articles et intérêts concurrents : une analyse des recommandations aux auteurs des journaux traitant de pratique pharmaceutique

    PubMed Central

    Courbon, Ève; Tanguay, Cynthia; Lebel, Denis; Bussières, Jean-François

    2014-01-01

    RÉSUMÉ Contexte : La présence d’auteurs honorifiques et fantômes ainsi que les intérêts concurrents représentent des difficultés bien documentées, liées à la publication d’articles scientifiques. Il existe des lignes directrices encadrant la rédaction et la publication de manuscrits scientifiques, notamment celles de l’International Committee of Medical Journal Editors (ICMJE). Objectifs : L’objectif principal de cette étude descriptive et transversale visait à recenser les instructions portant sur la paternité des articles et les intérêts concurrents provenant des recommandations aux auteurs des journaux traitant de pratique pharmaceutique. L’objectif secondaire visait à déterminer des mesures correctrices pour une paternité des articles plus transparente. Méthode : La recherche a débuté par l’identification des journaux traitant de pratique pharmaceutique. La consultation des instructions aux auteurs des journaux a permis ensuite de recenser les recommandations destinées à éviter les problèmes de paternité des articles et d’intérêts concurrents. Finalement, les membres de l’équipe de recherche se sont consultés afin de définir des mesures correctrices possibles à l’intention des chercheurs. Résultats : Des 232 journaux traitant de pharmacie, 33 ont été définis comme traitant de pratique pharmaceutique. Un total de 24 (73 %) journaux mentionnaient suivre la politique de l’ICMJE, 14 (42 %) demandaient aux auteurs de remplir un formulaire de déclaration d’intérêts concurrents au moment de la soumission de l’article, 17 (52 %) présentaient une définition de la qualité d’auteur et 5 (15 %) demandaient de détailler les contributions de chaque auteur. Une grille de 40 critères a été élaborée pour définir l’attribution du statut d’auteur. Conclusion : Moins de la moitié des journaux demandait aux auteurs de transmettre un formulaire de déclaration des intérêts concurrents au moment de la

  13. Le role du phytoplancton de petite taille (<20 mum) dans les variations des proprietes optiques des eaux du Saint-Laurent

    NASA Astrophysics Data System (ADS)

    Mas, Sebastien

    Les mesures satellitaires de couleur des oceans sont largement determinees par les proprietes optiques inherentes (IOPs) des eaux de surface. D'autre part, le phytoplancton de petite taille (<20 mum) est le plus souvent dominant dans les oceans, et peut donc etre une source importante de variation des IOPs dans les oceans. Dans ce contexte, le but principal de ce doctorat etait de definir l'impact du phytoplancton (<20 mum) sur les variations des proprietes optiques de l'Estuaire et du Golfe du Saint-Laurent (Canada). Afin d'atteindre cet objectif, il etait necessaire de determiner en milieu controle les facteurs de variabilite des proprietes optiques cellulaires et des IOPs du phytoplancton (<20 mum) des eaux du Saint-Laurent, et d'evaluer la contribution du phytoplancton (<20 mum) aux proprietes optiques totales des eaux du Saint-Laurent. Des experiences en laboratoire ont montre que les variations des proprietes optiques des cellules phytoplanctoniques soumises a un cycle jour-nuit, ainsi qu'a des changements concomitants d'intensite lumineuse, peuvent contribuer significativement a la variabilite des proprietes optiques observee en milieu naturel. D'autres experiences ont, quant a elles, mis en evidence que les variations des proprietes optiques des cellules phytoplanctoniques dues aux phases de croissance peuvent alterer les IOPs des oceans, particulierement pendant les periodes de floraison. De plus, la presence de bacteries et de particules detritiques peut egalement affecter la variabilite des IOPs totales, notamment la diffusion. Au printemps, dans l'Estuaire et le Golfe du Saint-Laurent, la contribution du phytoplancton <20 mum aux IOPs presentait des differences regionales evidentes pour les proprietes d'absorption et de diffusion. En plus de la variabilite spatiale, les proprietes optiques cellulaires presentaient des variations journalieres, et ce particulierement pour le picophytoplancton. Enfin, la plupart des differences observees dans les

  14. Pathophysiology of heart failure.

    PubMed

    Chiariello, M; Perrone-Filardi, P

    1999-01-01

    Heart failure is a leading cause of mortality and morbidity in Western countries. Common etiology is mostly represented by ischemic and hypertensive heart disease. Clinically, heart failure can be defined as an impaired cardiac performance, unable to meet the energy requirements of the periphery. Pathophysiologically, the clinical onset of heart failure symptoms already represents an advanced stage of disease when compensatory mechanisms triggered by the underlying decrease in contractility are no longer capable of maintaining adequate cardiac performance during exercise and, subsequently, under resting conditions. Independent of its underlying etiology, cardiac failure is always characterized by an impairment in the intrinsic contractility of myocytes. As a consequence of reduced contractility, a number of central and peripheral compensatory mechanisms take place that are capable of effectively counteracting reduced intravascular intrinsic performance for a long period of time. Among them, recruitment of preload reserve, enhanced neurohormonal stimulation and cardiac hypertrophy are the most important. All of them, however, also carry unfavorable effects that contribute to further deterioration of cardiac function. In fact, increased end-diastolic volume determines increased wall stress that further reduces systolic performance; sympathetic and angiotensin stimulation increases peripheral resistance and contributes to increase volume expansion; hypertrophic myocytes demonstrate impaired intrinsic contractility and relaxation, and hypertrophy causes a clinically relevant deterioration of ventricular relaxation and compliance that substantially participates in increased end-diastolic pressure, and, therefore, to limited exercise performance. Diastolic dysfunction usually accompanies systolic dysfunction, although in some cases it may represent the prevalent mechanism of congestive heart failure in patients in whom systolic performance is preserved. Biological causes

  15. Extensional Failure of "Pre-Stressed" Lithosphere Above a Subduction Zone May Have Contributed to the Size of the Tohoku-Oki Earthquake and Tsunami

    NASA Astrophysics Data System (ADS)

    Buck, W. R.; Lavier, L. L.; Petersen, K. D.

    2015-12-01

    The Tohoku-oki earthquake was not only the costliest natural disaster in history it was the best monitored. The unprecedented data set showed that anomalously large lateral motion of the seafloor near the trench contributed to the size of the tsunami. Also, for the first time it was shown that a large subduction earthquake was followed by extensional aftershocks in a broad region of the upper plate (up to 250 km from the Japan Trench). Several observations suggest that the near-trench seafloor motion and the extensional aftershocks are linked. For example, a seismically imaged fault, just landward of the region of large seafloor motion, slipped in a normal sense during the earthquake. Also, inspired by the Tohoku data, researchers have searched for and found upper plate extensional aftershocks associated with several other subduction earthquakes that produced large tsunami. Extension of the upper plate can be driven by a reduction in the dip of a subducting slab. Such a dip change is suggested by the post-Miocene westward migration of the volcanic arc in Honshu. Numerical models show that a long-term reduction in slab dip can generate enough extensional stress to cause normal faulting over a broad region of the upper plate. The time step of the numerical model is then reduced to treat the inter-seismic time scale of 100-1000 years, when the subduction interface is locked. The interface dip continues to be reduced during the inter-seismic period, but extensional fault slip is suppressed by the relative compression of the upper plate caused by continued convergence. The relief of compressional stresses during dynamic weakening of the megathrust triggers a release of bending-related extensional strain energy. This extensional yielding can add significantly to the co-seismic radiated seismic energy and seafloor deformation. This mechanism is analogous to the breaking of a pre-stressed concrete beam supporting a bending moment when the compressional pre-stress is

  16. Maladie des vibrations

    PubMed Central

    Shen, Shixin (Cindy); House, Ronald A.

    2017-01-01

    Résumé Objectif Permettre aux médecins de famille de comprendre l’épidémiologie, la pathogenèse, les symptômes, le diagnostic et la prise en charge de la maladie des vibrations, une maladie professionnelle importante et courante au Canada. Sources d’information Une recherche a été effectuée sur MEDLINE afin de relever les recherches et comptes rendus portant sur la maladie des vibrations. Une recherche a été effectuée sur Google dans le but d’obtenir la littérature grise qui convient au contexte canadien. D’autres références ont été tirées des articles relevés. Message principal La maladie des vibrations est une maladie professionnelle répandue touchant les travailleurs de diverses industries qui utilisent des outils vibrants. La maladie est cependant sous-diagnostiquée au Canada. Elle compte 3 éléments : vasculaire, sous la forme d’un phénomène de Raynaud secondaire; neurosensoriel; et musculosquelettique. Aux stades les plus avancés, la maladie des vibrations entraîne une invalidité importante et une piètre qualité de vie. Son diagnostic exige une anamnèse minutieuse, en particulier des antécédents professionnels, un examen physique, des analyses de laboratoire afin d’éliminer les autres diagnostics, et la recommandation en médecine du travail aux fins d’investigations plus poussées. La prise en charge consiste à réduire l’exposition aux vibrations, éviter les températures froides, abandonner le tabac et administrer des médicaments. Conclusion Pour assurer un diagnostic rapide de la maladie des vibrations et améliorer le pronostic et la qualité de vie, les médecins de famille devraient connaître cette maladie professionnelle courante, et pouvoir obtenir les détails pertinents durant l’anamnèse, recommander les patients aux cliniques de médecine du travail et débuter les demandes d’indemnisation de manière appropriée. PMID:28292812

  17. Des Vents et des Jets Astrophysiques

    NASA Astrophysics Data System (ADS)

    Sauty, C.

    well expected result from the theory. Although, collimation may be conical, paraboloidal or cylindrical (Part 4), cylindrical collimation is the more likely to occur. The shape of outflows may then be used as a tool to predict physical conditions on the flows or on their source. L'éjection continue de plasma autour d'objets massifs est un phénomène largement répandu en astrophysique, que ce soit sous la forme du vent solaire, de vents stellaires, de jets d'étoiles en formation, de jets stellaires autour d'objets compacts ou de jets extra-galactiques. Cette zoologie diversifiée fait pourtant l'objet d'un commun effort de modélisation. Le but de cette revue est d'abord de présenter qualitativement le développement, depuis leur origine, des diverses théories de vents (Partie 1) et l'inter disciplinarité dans ce domaine. Il s'agit d'une énumération, plus ou moins exhaustive, des idées proposées pour expliquer l'accélération et la morphologie des vents et des jets, accompagnée d'une présentation sommaire des aspects observationnels. Cette partie s'abstient de tout aspect faisant appel au formalisme mathématique. Ces écoulements peuvent être décrits, au moins partiellement, en résolvant les équations magnétohydrodynamiques, axisymétriques et stationnaires. Ce formalisme, à la base de la plupart des théories, est exposé dans la Partie 2. Il permet d'introduire quantitativement les intégrales premières qu'un tel système possède. Ces dernières sont amenées à jouer un rôle important dans la compréhension des phénomènes d'accélération ou de collimation, en particulier le taux de perte de masse, le taux de perte de moment angulaire ou l'énergie du rotateur magnétique. La difficulté de modélisation réside dans l'existence de points critiques, propres aux équations non linéaires, qu'il faut franchir. La nature physique et la localisation de ces points critiques fait l'objet d'un débat important car ils sont la clef de voute de la r

  18. Synthese Spectrale de Populations Stellaires des Galaxies: Separation des Effets D'age et de Metallicite

    NASA Astrophysics Data System (ADS)

    Delisle, Sonya

    Des observations spectroscopiques de 3 galaxies elliptiques normales, 4 lenticulaires, 2 bulbes de spirales (dont celui de la Voie Lactée) et 2 elliptiques naines péculières sont analysées. Les spectres couvrent d'environ 3900 à 10000 Å, donnant accès aux raies du visible qui sont sensibles soit à la métallicité, soit à l'âge. Les largeurs équivalentes des raies sont mesurées selon deux systèmes d'indices spectroscopiques. Les mesures sont faites à plusieurs distances radiales du centre de chaque galaxie afin d'obtenir des gradients. Les indices Hβ, et Mg2 sont comparés à des prédictions de modèles évolutifs théoriques de populations de façon à déterminer les abondances moyennes. Par la suite, deux codes de synthèse spectrale d'optimisation sont utilisés, avec deux bibliothèques spectrales empiriques et deux bibliothèques de largeurs équivalentes (dont une théorique), pour retrouver les contributions des différentes populations stellaires aux spectres intégrés des galaxies. L'information obtenue permettra de séparer les effets d'âge des effets de métallicité et de retracer l'historique de la formation stellaire.

  19. Evaluation of ultrafiltration failure.

    PubMed

    Korbet, S M

    1998-07-01

    The evaluation of ultrafiltration failure is embarked upon when a patient has persistent problems with symptoms and signs of fluid overload. Fluid overload is a common problem in peritoneal dialysis (PD) patients and the risk of its occurrence increases with time on dialysis. Although often attributed to changes in peritoneal membrane function (membrane failure), there are a number of potential, and frequently more common factors that can contribute to the failure of adequate fluid removal in patients on PD. Many of the causes of ultrafiltration failure may be apparent after an initial informal evaluation. However, if after this the etiology remains unexplained, a systematic approach to the differential diagnosis of this problem can be utilized with the use of the peritoneal equilibration test. Once a diagnosis is confirmed, a logical therapeutic plan can be formulated.

  20. Testicular failure

    MedlinePlus

    ... Blood tests may show a low level of testosterone and high levels of prolactin, FSH , and LH . ... testes will be ordered. Testicular failure and low testosterone level may be hard to diagnose in older ...

  1. Decompensated heart failure

    PubMed Central

    Mangini, Sandrigo; Pires, Philippe Vieira; Braga, Fabiana Goulart Marcondes; Bacal, Fernando

    2013-01-01

    ABSTRACT Heart failure is a disease with high incidence and prevalence in the population. The costs with hospitalization for decompensated heart failure reach approximately 60% of the total cost with heart failure treatment, and mortality during hospitalization varies according to the studied population, and could achieve values of 10%. In patients with decompensated heart failure, history and physical examination are of great value for the diagnosis of the syndrome, and also can help the physician to identify the beginning of symptoms, and give information about etiology, causes and prognosis of the disease. The initial objective of decompensated heart failure treatment is the hemodynamic and symptomatic improvement preservation and/or improvement of renal function, prevention of myocardial damage, modulation of the neurohormonal and/or inflammatory activation and control of comorbidities that can cause or contribute to progression of the syndrome. According to the clinical-hemodynamic profile, it is possible to establish a rational for the treatment of decompensated heart failure, individualizing the proceedings to be held, leading to reduction in the period of hospitalization and consequently reducing overall mortality. PMID:24136770

  2. Cartographie des disques

    NASA Astrophysics Data System (ADS)

    Hameury, Jean-Marie

    2001-01-01

    Two techniques are frequently used to produce images of the accretion disc in an eclipsing binary: eclipse mapping and Doppler tomography. From the light curve, one can deduce the radial distribution of the effective temperature, assuming axial symmetry. On the other hand, from the variation of the line profile one can reconstruct an image in the velocity space, which can be converted into a real image if one knows the kinematics of the system. Deux techniques sont couramment utilisées pour obtenir des images des disques dans les systèmes binaires à éclipses. En utilisant la courbe de lumière, on peut remonter à la distribution radiale de la brillance de surface, en supposant que celle-ci a une symètrie axiale. D'autre part, les profils de raies renseignent sur la distribution de vitesse des régions émissives leur variation temporelle permet de réaliser une image dans l'espace des vitesses, que l'on peut ensuite transformer en carte dans l'espace (x,y) si on connaît la cinématique du système.

  3. Injectabilite des coulis de ciment dans des milieux fissures

    NASA Astrophysics Data System (ADS)

    Mnif, Thameur

    Le travail presente ici est un bilan du travaux de recherche effectues sur l'injectabilite des coulis de ciment dans lu milieux fissures. Un certain nombre de coulis a base de ciment Portland et microfin ont ete selectionnes afin de caracteriser leur capacite a penetrer des milieux fissures. Une partie des essais a ete menee en laboratoire. L'etude rheologique des differents melanges a permis de tester l'influence de l'ajout de superplastifiant et/ou de fumee de silice sur la distribution granulometrique des coulis et par consequent sur leur capacite a injecter des colonnes de sable simulant un milieu fissure donne. La classe granulometrique d'un coulis, sa stabilite et sa fluidite sont apparus comme les trois facteurs principaux pour la reussite d'une injection. Un facteur de finesse a ete defini au cours de cette etude: base sur la classe granulometrique du ciment et sa stabilite, il peut entrer dans la formulation theorique du debit d'injection avant application sur chantier. La deuxieme et derniere partie de l'etude presente les resultats de deux projets de recherche sur l'injection realises sur chantier. L'injection de dalles de beton fissurees a permis le suivi de l'evolution des pressions avec la distance au point d'injection. L'injection de murs de maconnerie a caractere historique a montre l'importance de la definition de criteres de performance des coulis a utiliser pour traiter un milieu donne et pour un objectif donne. Plusieurs melanges peuvent ainsi etre predefinis et mis a disposition sur le chantier. La complementarite des ciments traditionnels et des ciments microfins devient alors un atout important. Le choix d'utilisation de ces melanges est fonction du terrain rencontre. En conclusion, cette recherche etablit une methodologie pour la selection des coulis a base de ciment et des pressions d'injection en fonction de l'ouverture des fissures ou joints de construction.

  4. Heart failure

    PubMed Central

    2011-01-01

    Introduction Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of multidisciplinary interventions for heart failure? What are the effects of exercise in people with heart failure? What are the effects of drug treatments for heart failure? What are the effects of devices for treatment of heart failure? What are the effects of coronary revascularisation for treatment of heart failure? What are the effects of drug treatments in people at high risk of heart failure? What are the effects of treatments for diastolic heart failure? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 80 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: aldosterone receptor antagonists, amiodarone, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, anticoagulation, antiplatelet agents, beta-blockers, calcium

  5. Simulation de l'accretion de glace sur un obstacle bidimensionnel par la methode des bissectrices et par la modelisation des ruisselets et des gouttes de surface

    NASA Astrophysics Data System (ADS)

    Fortin, Guy

    Le LIMA (Laboratoire International des Materiaux Antigivre) en collaboration avec le CIRA (Italian Aerospace Research Centre) a developpe un logiciel simulant l'accretion de la glace en regimes sec et humide sur un objet bidimensionnel fixe. L'approche utilisee s'appuie sur les travaux de Lozowski pour les bilans energetiques, sur une etude du comportement du film d'eau, des ruisselets et des gouttes de surface pour le calcul des rugosites et des masses d'eau residuelle, ainsi que sur une methode de bissectrice pour l'evolution de la surface de glace. La contribution du CIRA a ete de fournir le logiciel pour le calcul des ecoulements et de la captation. Le bilan energetique base sur la conservation de l'energie est la sommation de la chaleur latente de fusion, d'evaporation et de sublimation, du rechauffement adiabatique et cinetique, et des pertes de chaleur par convection et conduction, ainsi que de l'evolution thermodynamique de l'eau de son etat initial a son etat final. La densite de la glace, qui a un impact important sur la simulation, est calculee a partir d'une correlation empirique developpee avec les cylindres tournants. En se basant sur les travaux de Al-Khalil et Hansman, le comportement des gouttes en regimes sec et humide a ete decrit analytiquement, ce qui a mene a determiner la hauteur maximale que peuvent atteindre les gouttes avant mouvement. Cette hauteur, appelee hauteur de mouvement, permet de determiner l'etat de l'eau sur la surface (film, ruisselets ou gouttes), ainsi que la hauteur des rugosites lorsque l'eau existe sous forme de gouttes ou de ruisselets. La hauteur de mouvement est determinee par l'equilibre entre les forces de cisaillement, induites par les effets aerodynamiques et gravitationnels evalues pour une goutte non deformee, et la force de cisaillement, induite par la tension de surface et la deformation de la goutte. Elle a ete validee en laboratoire et la precision obtenue pour la partie aerodynamique et gravitationnelle est

  6. Heart failure

    PubMed Central

    2010-01-01

    Introduction Heart failure occurs in 3% to 4% of adults aged over 65 years, usually as a consequence of coronary artery disease or hypertension, and causes breathlessness, effort intolerance, fluid retention, and increased mortality. The 5-year mortality in people with systolic heart failure ranges from 25% to 75%, often owing to sudden death following ventricular arrhythmia. Risks of cardiovascular events are increased in people with left ventricular systolic dysfunction (LVSD) or heart failure. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of non-drug treatments, and of drug and invasive treatments, for heart failure? What are the effects of angiotensin-converting enzyme inhibitors in people at high risk of heart failure? What are the effects of treatments for diastolic heart failure? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 85 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: aldosterone receptor antagonists, amiodarone, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, anticoagulation, antiplatelet agents, beta-blockers, calcium channel blockers, cardiac resynchronisation therapy, digoxin (in people already receiving diuretics and angiotensin-converting enzyme inhibitors), exercise, hydralazine plus isosorbide dinitrate, implantable cardiac

  7. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Rob; Novack, Steven D.

    2015-01-01

    Common Cause Failures (CCFs) are a known and documented phenomenon that defeats system redundancy. CCFS are a set of dependent type of failures that can be caused by: system environments; manufacturing; transportation; storage; maintenance; and assembly, as examples. Since there are many factors that contribute to CCFs, the effects can be reduced, but they are difficult to eliminate entirely. Furthermore, failure databases sometimes fail to differentiate between independent and CCF (dependent) failure and data is limited, especially for launch vehicles. The Probabilistic Risk Assessment (PRA) of NASA's Safety and Mission Assurance Directorate at Marshall Space Flight Center (MFSC) is using generic data from the Nuclear Regulatory Commission's database of common cause failures at nuclear power plants to estimate CCF due to the lack of a more appropriate data source. There remains uncertainty in the actual magnitude of the common cause risk estimates for different systems at this stage of the design. Given the limited data about launch vehicle CCF and that launch vehicles are a highly redundant system by design, it is important to make design decisions to account for a range of values for independent and CCFs. When investigating the design of the one-out-of-two component redundant system for launch vehicles, a response surface was constructed to represent the impact of the independent failure rate versus a common cause beta factor effect on a system's failure probability. This presentation will define a CCF and review estimation calculations. It gives a summary of reduction methodologies and a review of examples of historical CCFs. Finally, it presents the response surface and discusses the results of the different CCFs on the reliability of a one-out-of-two system.

  8. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Rob; Novack, Steven D.

    2016-01-01

    Common Cause Failures (CCFs) are a known and documented phenomenon that defeats system redundancy. CCFS are a set of dependent type of failures that can be caused by: system environments; manufacturing; transportation; storage; maintenance; and assembly, as examples. Since there are many factors that contribute to CCFs, the effects can be reduced, but they are difficult to eliminate entirely. Furthermore, failure databases sometimes fail to differentiate between independent and CCF (dependent) failure and data is limited, especially for launch vehicles. The Probabilistic Risk Assessment (PRA) of NASA's Safety and Mission Assurance Directorate at Marshal Space Flight Center (MFSC) is using generic data from the Nuclear Regulatory Commission's database of common cause failures at nuclear power plants to estimate CCF due to the lack of a more appropriate data source. There remains uncertainty in the actual magnitude of the common cause risk estimates for different systems at this stage of the design. Given the limited data about launch vehicle CCF and that launch vehicles are a highly redundant system by design, it is important to make design decisions to account for a range of values for independent and CCFs. When investigating the design of the one-out-of-two component redundant system for launch vehicles, a response surface was constructed to represent the impact of the independent failure rate versus a common cause beta factor effect on a system's failure probability. This presentation will define a CCF and review estimation calculations. It gives a summary of reduction methodologies and a review of examples of historical CCFs. Finally, it presents the response surface and discusses the results of the different CCFs on the reliability of a one-out-of-two system.

  9. Impact of Incidental Irradiation on Clinically Uninvolved Nodal Regions in Patients With Advanced Non-Small-Cell Lung Cancer Treated With Involved-Field Radiation Therapy: Does Incidental Irradiation Contribute to the Low Incidence of Elective Nodal Failure?

    SciTech Connect

    Kimura, Tomoki; Togami, Taro; Nishiyama, Yoshihiro; Ohkawa, Motoomi; Takashima, Hitoshi

    2010-06-01

    Purpose: To evaluate the incidental irradiation dose to elective nodal regions in the treatment of advanced non-small-cell lung cancer with involved-field radiation therapy (IF-RT) and the pattern of elective nodal failure (ENF). Methods and Materials: Fifty patients with advanced non-small-cell lung cancer, who received IF-RT at Kagawa University were enrolled. To evaluate the dose of incidental irradiation, we delineated nodal regions with a Japanese map and the American Thoracic Society map (levels 1-11) in each patient retrospectively and calculated the dose parameters such as mean dose, D95, and V95 (40 Gy as the prescribed dose of elective nodal irradiation). Results: Using the Japanese map, the median mean dose was more than 40 Gy in most of the nodal regions, except at levels 1, 3, and 7. In particular, each dosimetric parameter of level 1 was significantly lower than those at other levels, and each dosimetric parameter of levels 10 to 11 ipsilateral (11I) was significantly higher than those in other nodal regions. Using the American Thoracic Society map, basically, the results were similar to those of the Japanese map. ENF was observed in 4 patients (8%), five nodal regions, and no mean dose to the nodal region exceeded 40 Gy. On the Japanese map, each parameter of these five nodal region was significantly lower than those of the other nodal regions. Conclusions: These results show that a high dose of incidental irradiation may contribute to the low incidence of ENF in patients who have received IF-RT.

  10. Grundlagen des Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Mayer, Jörg; Blum, Janaki; Wintermantel, Erich

    Die Organtransplantation stellt eine verbreitete Therapie dar, um bei krankheitsoder unfallbedingter Schädigung eines Organs die Gesamtheit seiner Funktionen wieder herzustellen, indem es durch ein Spenderorgan ersetzt wird. Organtransplantationen werden für die Leber, die Niere, die Lunge, das Herz oder bei schweren grossflächigen Verbrennungen der Haut vorgenommen. Der grosse apparative, personelle und logistische Aufwand und die Risiken der Transplantationschirurgie (Abstossungsreaktionen) sowie die mangelnde Verfügbarkeit von immunologisch kompatiblen Spenderorganen führen jedoch dazu, dass der Bedarf an Organtransplantaten nur zu einem sehr geringen Teil gedeckt werden kann. Sind Spenderorgane nicht verfügbar, können in einzelnen Fällen lebenswichtige Teilfunktionen, wie beispielsweise die Filtrationsfunktion der Niere durch die Blutreinigung mittels Dialyse ersetzt oder, bei mangelnder Funktion der Bauchspeicheldrüse (Diabetes), durch die Verabreichung von Insulin ein normaler Zustand des Gesamtorganismus auch über Jahre hinweg erhalten werden. Bei der notwendigen lebenslangen Anwendung apparativer oder medikamentöser Therapie können für den Patienten jedoch häufig schwerwiegende, möglicherweise lebensverkürzende Nebenwirkungen entstehen. Daher werden in der Forschung Alternativen gesucht, um die Funktionen des ausgefallenen Organs durch die Implantation von Zellen oder in vitro gezüchteten Geweben möglichst umfassend wieder herzustellen. Dies erfordert biologisch aktive Implantate, welche die für den Stoffwechsel des Organs wichtigen Zellen enthalten und einen organtypischen Stoffwechsel entfalten.

  11. Kidney (Renal) Failure

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Kidney Failure Kidney failure, also known as renal failure, ... evaluated? How is kidney failure treated? What is kidney (renal) failure? The kidneys are designed to maintain ...

  12. Reticulation des fibres lignocellulosiques

    NASA Astrophysics Data System (ADS)

    Landrevy, Christel

    Pour faire face à la crise économique la conception de papier à valeur ajoutée est développée par les industries papetières. Le but de se projet est l'amélioration des techniques actuelles de réticulation des fibres lignocellulosiques de la pâte à papier visant à produire un papier plus résistant. En effet, lors des réactions de réticulation traditionnelles, de nombreuses liaisons intra-fibres se forment ce qui affecte négativement l'amélioration anticipée des propriétés physiques du papier ou du matériau produit. Pour éviter la formation de ces liaisons intra-fibres, un greffage sur les fibres de groupements ne pouvant pas réagir entre eux est nécessaire. La réticulation des fibres par une réaction de « click chemistry » appelée cycloaddition de Huisgen entre un azide et un alcyne vrai, catalysée par du cuivre (CuAAC) a été l'une des solutions trouvée pour remédier à ce problème. De plus, une adaptation de cette réaction en milieux aqueux pourrait favoriser son utilisation en milieu industriel. L'étude que nous désirons entreprendre lors de ce projet vise à optimiser la réaction de CuAAC et les réactions intermédiaires (propargylation, tosylation et azidation) sur la pâte kraft, en milieu aqueux. Pour cela, les réactions ont été adaptées en milieu aqueux sur la cellulose microcristalline afin de vérifier sa faisabilité, puis transférée à la pâte kraft et l'influence de différents paramètres comme le temps de réaction ou la quantité de réactifs utilisée a été étudiée. Dans un second temps, une étude des différentes propriétés conférées au papier par les réactions a été réalisée à partir d'une série de tests papetiers optiques et physiques. Mots Clés Click chemistry, Huisgen, CuAAC, propargylation, tosylation, azidation, cellulose, pâte kraft, milieu aqueux, papier.

  13. Biomarkers for Heart Failure in Asia.

    PubMed

    Richards, Arthur Mark

    2015-10-01

    Contributions from the Asian biomedical community to knowledge of biomarkers in heart failure have grown rapidly since 2000. Japan has made world-leading contributions in the discovery and application of cardiac natriuretic peptides as biomarkers in heart failure, but there has been rapid growth in reports from China. Contributions also come from Taiwan, South Korea, Singapore, and Hong Kong. Centers in Asia have established clinical cohorts providing powerful platforms for the discovery and validation of biomarkers in heart failure. This century, Asian enquiry into biomarkers in heart failure will include peptides, cytokines, metabolites, nucleic acids, and other analytes. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. La diffraction des neutrons et des rayons X pour l'étude structurale des liquides et des verres

    NASA Astrophysics Data System (ADS)

    Fischer, H. E.; Salmon, P. S.; Barnes, A. C.

    2003-02-01

    La compréhension de mainte propriété physique d'un verre ou d'un liquide nécessite la connaissance des facteurs de structure partiels (PSFs) qui décrivent chacun la distribution d'une espèce atomique autour d'une autre. La technique de diffraction des neutrons avec substitution isotopique (NDIS) [1,2,3], ayant bien réussi a déterminer les PSFs de certains composés [4,5], est pourtant restreinte aux isotopes présentant un contraste suffisant en longueur de diffusion. D'un autre cote, la technique de diffusion anomale des rayons X (AXS ou AXD) [6] permet de faire varier la longueur de diffusion d'une espèce atomique pourvu que son énergie d'absorption soit à la fois accessible et suffisamment élevée pour donner un assez grand transfert du moment. La combinaison des techniques de diffraction des neutrons (avec ou sans substitution isotopique) et de diffraction des rayons X (avec ou sans diffusion anomale) peut donc permettre d'obtenir un meilleur contraste en longueurs de diffusion pour un système donné, mais exige une analyse de données plus soignée pour pouvoir bien tenir compte des erreurs systématiques qui sont différentes pour les 2 techniques [7]. Pour les atomes ayant des distributions électroniques quasi-sphériques, e.g. dans le cas d'un alliage liquide, la combinaison des techniques de NDIS et de diffraction des rayons X s'est déjà montrée très avantageuse pour la détermination des PSFs [8,9]. Dans le cas des verres ayant d'importantes liaisons covalentes, l'effective combinaison des 2 techniques peut être moins directe mais facilitée lorsqu'il s'agit des atomes de grand Z [10,11]. Nous présentons ici un sommaire du méthode et quelques exemples des résultats.

  15. Choice of DES: is there a difference?

    PubMed Central

    Kaul, U; Bhatia, V

    2009-01-01

    Restenosis after percutaneous coronary interventions has been a major limitation of this otherwise very well-accepted method of coronary revascularisation. Coronary stents work by scaffolding the intimal flaps and preventing elastic recoil, which was a major problem after balloon angioplasty. The neointimal growth response to stenting contributes significantly to the restenotic process. Randomised studies comparing coronary artery bypass surgery with coronary stenting especially in multivessel disease clearly highlighted this problem. The problem has been greater in magnitude in special subgroups: diabetics, patients with small vessels (≤2.5 mm in diameter), long segments of disease (≥20 mm in length), etc. These limitations of Bare metal stents have been addressed by drug-eluting stents (DESs). Third-generation stents with bioabsorbable polymers like the Biolimus releasing Biomatrix stent have already become available in Europe and parts of Asia. A longer follow-up will prove their long-term safety vis-à-vis first-generation DES. The polymer-free stent with capability of using more than one drug, though very attractive, needs larger multicentric studies before gaining wider acceptance. The fully bioabsorbable stent is yet another promising concept. The feasibility has already been demonstrated, and finer refinements are under way. The future of newer DES thus is very promising, and most of the issues related to first-generation DES are at the threshold of being solved. PMID:27325919

  16. Metallization failures

    NASA Technical Reports Server (NTRS)

    Beatty, R.

    1971-01-01

    Metallization-related failure mechanisms were shown to be a major cause of integrated circuit failures under accelerated stress conditions, as well as in actual use under field operation. The integrated circuit industry is aware of the problem and is attempting to solve it in one of two ways: (1) better understanding of the aluminum system, which is the most widely used metallization material for silicon integrated circuits both as a single level and multilevel metallization, or (2) evaluating alternative metal systems. Aluminum metallization offers many advantages, but also has limitations particularly at elevated temperatures and high current densities. As an alternative, multilayer systems of the general form, silicon device-metal-inorganic insulator-metal, are being considered to produce large scale integrated arrays. The merits and restrictions of metallization systems in current usage and systems under development are defined.

  17. Contribution des surfaces saturées et des versants aux flux d'eau et d'éléments exportés en période de crue: traçage à l'aide du carbone organique dissous et de la silice. Cas du petit bassin versant du Strengbach (Vosges, France)

    NASA Astrophysics Data System (ADS)

    Idir, Samir; Probst, Anne; Viville, Daniel; Probst, Jean-Luc

    1999-01-01

    Two contributing areas have been determined in the small forested Strengbach catchment by using dissolved organic carbon (DOC) and dissolved silica as the most efficient chemical tracers of stream water origin during a storm event. Dissolved silica represents the deep layers of the hillslopes which contributes 71-75 % of the total storm runoff and 85-99 % of the fluxes of major elements exported by the Strengbach. DOC corresponds to the saturated areas which occupy only 2 % of the total catchment area but which supply 25-29 % of the total streamflow and 56 % of the DOC stream flux. The specific fluxes of water (L·s -1·ha -1) and elements (kg·ha -1) are much more important in the saturared areas than in the rest of the catchment.

  18. A Magellanic origin of the DES dwarfs

    NASA Astrophysics Data System (ADS)

    Jethwa, P.; Erkal, D.; Belokurov, V.

    2016-09-01

    We establish the connection between the Magellanic Clouds (MCs) and the dwarf galaxy candidates discovered in the Dark Energy Survey (DES) by building a dynamical model of the MC satellite populations, based on an extensive suite of tailor-made numerical simulations. Our model takes into account the response of the Galaxy to the MCs infall, the dynamical friction experienced by the MCs and the disruption of the MC satellites by their hosts. The simulation suite samples over the uncertainties in the MC's proper motions, the masses of the MW and the Clouds themselves, and allows for flexibility in the intrinsic volume density distribution of the MC satellites. As a result, we can accurately reproduce the DES satellites' observed positions and kinematics. Assuming that Milky Way (MW) dwarfs follow the distribution of sub-haloes in Λ cold dark matter, we further demonstrate that, of 14 observed satellites, the MW halo contributes fewer than 4(8) of these with 68(95) per cent confidence and that 7(12) DES dwarfs have probabilities greater than 0.7(0.5) of belonging to the Large Magellanic Cloud (LMC). Marginalizing over the entire suite, we constrain the number of Magellanic satellites in the range -7 < MV < -1 which exceed the DES surface brightness threshold at ˜70, and the mass of the LMC around 1011 M⊙. The data also strongly support a first-infall scenario for the LMC. Finally, we give predictions for the line-of-sight velocities and the proper motions of the satellites discovered in the vicinity of the LMC.

  19. Diabetes Mellitus and Heart Failure.

    PubMed

    Lehrke, Michael; Marx, Nikolaus

    2017-06-01

    Epidemiologic and clinical data from the last 2 decades have shown that the prevalence of heart failure in diabetes is very high, and the prognosis for patients with heart failure is worse in those with diabetes than in those without diabetes. Experimental data suggest that various mechanisms contribute to the impairment in systolic and diastolic function in patients with diabetes, and there is an increased recognition that these patients develop heart failure independent of the presence of coronary artery disease or its associated risk factors. In addition, current clinical data demonstrated that treatment with the sodium glucose cotransporter 2 inhibitor empagliflozin reduced hospitalization for heart failure in patients with type 2 diabetes mellitus and high cardiovascular risk. This review article summarizes recent data on the prevalence, prognosis, pathophysiology, and therapeutic strategies to treat patients with diabetes and heart failure. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Diabetes Mellitus and Heart Failure.

    PubMed

    Lehrke, Michael; Marx, Nikolaus

    2017-07-01

    Epidemiologic and clinical data from the last 2 decades have shown that the prevalence of heart failure in diabetes is very high, and the prognosis for patients with heart failure is worse in those with diabetes than in those without diabetes. Experimental data suggest that various mechanisms contribute to the impairment in systolic and diastolic function in patients with diabetes, and there is an increased recognition that these patients develop heart failure independent of the presence of coronary artery disease or its associated risk factors. In addition, current clinical data demonstrated that treatment with the sodium glucose cotransporter 2 inhibitor empagliflozin reduced hospitalization for heart failure in patients with type 2 diabetes mellitus and high cardiovascular risk. This review article summarizes recent data on the prevalence, prognosis, pathophysiology, and therapeutic strategies to treat patients with diabetes and heart failure. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  1. La participation des enfants et des adolescents à la boxe

    PubMed Central

    Purcell, Laura K; LeBlanc, Claire MA

    2012-01-01

    RÉSUMÉ Des milliers de garçons et de filles de moins de 19 ans font de la boxe en Amérique du Nord. Même si la boxe comporte des avantages pour ceux qui y participent, y compris l’exercice, l’autodiscipline et la confiance en soi, le sport lui-même favorise et récompense des coups délibérés à la tête et au visage. Les personnes qui font de la boxe risquent de subir des blessures à la tête, au visage et au cou, y compris des traumatismes neurologiques chroniques et même fatals. Les commotions cérébrales sont l’une des principales blessures causées par la boxe. En raison du risque de blessures crâniennes et faciales, la Société canadienne de pédiatrie et l’American Academy of Pediatrics s’opposent vigoureusement à la boxe comme activité sportive pour les enfants et les adolescents. Ces organismes recommandent que les médecins s’élèvent contre la boxe auprès des jeunes et les encouragent à participer à d’autres activités dans lesquelles les coups intentionnels à la tête ne constituent pas un élément essentiel du sport.

  2. Heart failure.

    PubMed

    Braunwald, Eugene

    2013-02-01

    Despite major improvements in the treatment of virtually all cardiac disorders, heart failure (HF) is an exception, in that its prevalence is rising, and only small prolongations in survival are occurring. An increasing fraction, especially older women with diabetes, obesity, and atrial fibrillation exhibit HF with preserved systolic function. Several pathogenetic mechanisms appear to be operative in HF. These include increased hemodynamic overload, ischemia-related dysfunction, ventricular remodeling, excessive neurohumoral stimulation, abnormal myocyte calcium cycling, excessive or inadequate proliferation of the extracellular matrix, accelerated apoptosis, and genetic mutations. Biomarkers released as a consequence of myocardial stretch, imbalance between formation and breakdown of extracellular matrix, inflammation, and renal failure are useful in the identification of the pathogenetic mechanism and, when used in combination, may become helpful in estimating prognosis and selecting appropriate therapy. Promising new therapies that are now undergoing intensive investigation include an angiotensin receptor neprilysin inhibitor, a naturally-occurring vasodilator peptide, a myofilament sensitizer and several drugs that enhance Ca++ uptake by the sarcoplasmic reticulum. Cell therapy, using autologous bone marrow and cardiac progenitor cells, appears to be promising, as does gene therapy. Chronic left ventricular assistance with continuous flow pumps is being applied more frequently and successfully as destination therapy, as a bridge to transplantation, and even as a bridge to recovery and explantation. While many of these therapies will improve the care of patients with HF, significant reductions in prevalence will require vigorous, multifaceted, preventive approaches.

  3. Les Applications Therapeutiques Des Lasers

    NASA Astrophysics Data System (ADS)

    Brunetaud, J. M.; Mordon, S.; Bourez, J.; Mosquet, L.; Moschetto, Y.

    1984-03-01

    C'est de tres loin le mecanisme predominant dans les applications therapeutiques du laser. En concentrant le flux lumineux sur une surface redui-te, le laser chauffe localement les tissus qui se retractent (coagulation) pour etre elimines ensuite (detersion) ; si on chauffe plus intensement, les tissus peuvent etre volatilises. La coagulation est utilisee soit pour detruire de petits phenomenes tumoraux qui seront elimines lors du processus de detersion, soit pour arreter une hemorragie (hemo-stase) ; dans ce cas la retraction thermique des tissus va provoquer la fermeture de la lumiere des vaisseaux qui seront secondairement obliteres par des caillots formes sur place (thrombose). Par volatilisation it est possible de detruire des phenomenes tumoraux plus importants que ceux at-teints lors d'une simple coagulation. Si la zone volatilisee est tres etroite (de 0,1 a 1 mm) on obtient un effet de coupe avec une excellente hemostase au niveau des berges. Certes ces deux processus - coagulation et volatilisation - peuvent etre obtenus par d'autres procedes : echauffement par contact (sonde thermique) ou effet Joule (courant electrique haute frequence). Le laser a l'avantage de ne necessiter aucun contact mecanique entre le vecteur d'energie et les tissus ; on peut alors predire correctement la repartition d'energie au niveau des tissus et les effets sont tres repro-ductibles. Par ailleurs, l'absorption tissulaire variant considerablement avec la longueur d'onde on peut choisir la source laser en fonction des effets desires.

  4. Médecine des voyages

    PubMed Central

    Aw, Brian; Boraston, Suni; Botten, David; Cherniwchan, Darin; Fazal, Hyder; Kelton, Timothy; Libman, Michael; Saldanha, Colin; Scappatura, Philip; Stowe, Brian

    2014-01-01

    Résumé Objectif Définir la pratique de la médecine des voyages, présenter les éléments fondamentaux d’une consultation complète préalable aux voyages à des voyageurs internationaux et aider à identifier les patients qu’il vaudrait mieux envoyer en consultation auprès de professionnels de la médecine des voyages. Sources des données Les lignes directrices et les recommandations sur la médecine des voyages et les maladies liées aux voyages publiées par les autorités sanitaires nationales et internationales ont fait l’objet d’un examen. Une recension des ouvrages connexes dans MEDLINE et EMBASE a aussi été effectuée. Message principal La médecine des voyages est une spécialité très dynamique qui se concentre sur les soins préventifs avant un voyage. Une évaluation exhaustive du risque pour chaque voyageur est essentielle pour mesurer avec exactitude les risques particuliers au voyageur, à son itinéraire et à sa destination et pour offrir des conseils sur les interventions les plus appropriées en gestion du risque afin de promouvoir la santé et prévenir les problèmes médicaux indésirables durant le voyage. Des vaccins peuvent aussi être nécessaires et doivent être personnalisés en fonction des antécédents d’immunisation du voyageur, de son itinéraire et du temps qu’il reste avant son départ. Conclusion La santé et la sécurité d’un voyageur dépendent du degré d’expertise du médecin qui offre le counseling préalable à son voyage et les vaccins, au besoin. On recommande à ceux qui donnent des conseils aux voyageurs d’être conscients de l’ampleur de cette responsabilité et de demander si possible une consultation auprès de professionnels de la médecine des voyages pour tous les voyageurs à risque élevé.

  5. Mecanique et mecanisme de la dechirure des materiaux textiles

    NASA Astrophysics Data System (ADS)

    Triki, Ennouri

    Cette thèse vise à apporter une contribution à l’étude et à la modélisation de la déchirure des textiles et des textiles enduits. Notons que la résistance à la déchirure est l’une des caractéristiques mesurées pour les équipements de protection contre les agresseurs mécaniques en milieu de travail. Jusqu'à présent, ce comportement en déchirure a été étudié en mesurant la force de déchirure et le travail de déchirure. De fait, aucun critère de rupture en déchirure n’existe actuellement. Par conséquent, en s’inspirant de la théorie du Griffith et de la mécanique de la rupture, une formulation d’un nouveau critère de rupture des structures textiles a été proposée. Cette approche offre la possibilité de déterminer d’une manière plus précise l’énergie nécessaire pour la création d’une nouvelle surface de rupture. Ce critère nous permet d’analyser l’effet des caractéristiques des tissus sur la variation de l’énergie de rupture. Cette étude montre que la résistance au glissement des fils dans la structure est le principal facteur qui contrôle la propagation de la fissure. En se basant sur la théorie de la mécanique de la rupture, un modèle de calcul de l’énergie de rupture par déchirure a été aussi élaboré. Ce modèle de déchirure relie l’énergie aux paramètres caractérisant les phénomènes affectant la déchirure des tissus, notamment la force de glissement et la force à la rupture des fils. Cette modélisation a tenu compte de certaines caractéristiques des tissus tels que l’épaisseur du matériau, la densité des fils, etc. Par l’étude de la variation de l’énergie de rupture par déchirure en fonction du rapport établi entre la force à la rupture et la force de glissement d’un fil ( FYB/FS), l’effet des mécanismes de la propagation de la fissure dans les tissus sur leur comportement en déchirure a été aussi observé. Les résultats obtenus

  6. Towards a Dynamic DES model

    NASA Astrophysics Data System (ADS)

    Subbareddy, Pramod; Candler, Graham

    2009-11-01

    Hybrid RANS/LES methods are being increasingly used for turbulent flow simulations in complex geometries. Spalart's detached eddy simulation (DES) model is one of the more popular ones. We are interested in examining the behavior of the Spalart-Allmaras (S-A) Detached Eddy Simulation (DES) model in its ``LES mode.'' The role of the near-wall functions present in the equations is analyzed and an explicit analogy between the S-A and a one-equation LES model based on the sub-grid kinetic energy is presented. A dynamic version of the S-A DES model is proposed based on this connection. Validation studies and results from DES and LES applications will be presented and the effect of the proposed modification will be discussed.

  7. Heart Failure in North America

    PubMed Central

    Blair, John E. A; Huffman, Mark; Shah, Sanjiv J

    2013-01-01

    Heart failure is a major health problem that affects patients and healthcare systems worldwide. Within the continent of North America, differences in economic development, genetic susceptibility, cultural practices, and trends in risk factors and treatment all contribute to both inter-continental and within-continent differences in heart failure. The United States and Canada represent industrialized countries with similar culture, geography, and advanced economies and infrastructure. During the epidemiologic transition from rural to industrial in countries such as the United States and Canada, nutritional deficiencies and infectious diseases made way for degenerative diseases such as cardiovascular diseases, cancer, overweight/obesity, and diabetes. This in turn has resulted in an increase in heart failure incidence in these countries, especially as overall life expectancy increases. Mexico, on the other hand, has a less developed economy and infrastructure, and has a wide distribution in the level of urbanization as it becomes more industrialized. Mexico is under a period of epidemiologic transition and the etiology and incidence of heart failure is rapidly changing. Ethnic differences within the populations of the United States and Canada highlight the changing demographics of each country as well as potential disparities in heart failure care. Heart failure with preserved ejection fraction makes up approximately half of all hospital admissions throughout North America; however, important differences in demographics and etiology exist between countries. Similarly, acute heart failure etiology, severity, and management differ between countries in North America. The overall economic burden of heart failure continues to be large and growing worldwide, with each country managing this burden differently. Understanding the inter-and within-continental differences may help improve understanding of the heart failure epidemic, and may aid healthcare systems in delivering

  8. Contribution to the G0 violation of parity experience: calculation and simulation of radiative corrections and the background noise study; Contribution a l'experience G0 de violation de la parite : calcul et simulation des corrections radiatives et etude du bruit de fond

    SciTech Connect

    Guler, Hayg

    2003-12-17

    In the framework of quantum chromodynamics, the nucleon is made of three valence quarks surrpounded by a sea of gluons and quark-antiquark pairs. Only the only lightest quarks (u, d and s) contribute significantly to the nucleon properties. In Go we using the property of weak interaction to violate parity symmetry, in order to determine separately the contributions of the three types of quarks to nucleon form factors. The experiment, which takes place at Thomas Jefferson laboratory (USA), aims at measuring parity violation asymmetry in electron-proton scattering. By doing several measurements at different momentum squared of the exchanged photons and for different kinematics (forward angle when the proton is detected and backward angle it will be the electron) will permit to determine separately strange quarks electric and magnetic contributions to nucleon form factors. To extract an asymmetry with small errors, it is necessary to correct all the beam parameters, and to have high enough counting rates in detectors. A special electronics was developed to treat information coming from 16 scintillator pairs for each of the 8 sectors of the Go spectrometer. A complete calculation of radiative corrections has been clone and Monte Carlo simulations with the GEANT program has permitted to determine the shape of the experimental spectra including inelastic background. This work will allow to do a comparison between experimental data and theoretical calculations based on the Standard Model.

  9. Failure Analysis at the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Salazar, Victoria L.; Wright, M. Clara

    2010-01-01

    History has shown that failures occur in every engineering endeavor, and what we learn from those failures contributes to the knowledge base to safely complete future missions. The necessity of failure analysis is at its apex at the end of one aged program and at the beginning of a new and untested program. The information that we gain through failure analysis corrects the deficiencies in the current vehicle to make the next generation of vehicles more efficient and safe. The Failure Analysis and Materials Evaluation Branch in the Materials Science Division at the Kennedy Space Center performs metallurgical, mechanical, electrical, and non-metallic materials failure analyses and accident investigations on both flight hardware and ground support equipment for the Space Shuttle, International Space Station, Constellation, and Launch Services Programs. This paper will explore a variety of failure case studies at the Kennedy Space Center and the lessons learned that can be applied in future programs.

  10. Failure Analysis at the Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Salazar, Victoria L.; Wright, Clara

    2010-01-01

    History has shown that failures occur in every engineering endeavor, and what we learn from those failures contributes to the knowledge base to safely complete future missions. The necessity of failure analysis is at its apex at the end of one aged program (i.e. Shuttle) and at the beginning of a new and untested program (i.e. Constellation). The information that we gain through failure analysis corrects the deficiencies in the current vehicle to make the next generation of vehicles more efficient and safe. The Failure Analysis and Materials Evaluation section in the Materials Science Division at the Kennedy Space Center performs metallurgical, mechanical, electrical, and non-metallic failure analysis and accident investigations on both flight hardware and ground support equipment (GSE) for the Shuttle, International Space Station, Constellation, and Launch Services Programs. This presentation will explore a variety of failure case studies at KSC and the lessons learned that can be applied in future programs.

  11. Depression, Anxiety and Heart Failure: A Review

    DTIC Science & Technology

    2005-03-08

    Although common among patients with heart failure, depression and anxiety have been relatively neglected by researchers and practitioners. Both... depression and anxiety have been implicated in contributing independently to the poor outcomes seen in patients with heart failure. Emphasis in the...This review summarizes and integrates research findings on anxiety and depression and translates these findings to clinical practice. Depression and

  12. Peste des petits ruminants.

    PubMed

    Parida, S; Muniraju, M; Mahapatra, M; Muthuchelvan, D; Buczkowski, H; Banyard, A C

    2015-12-14

    Peste des petits ruminants virus causes a highly infectious disease of small ruminants that is endemic across Africa, the Middle East and large regions of Asia. The virus is considered to be a major obstacle to the development of sustainable agriculture across the developing world and has recently been targeted by the World Organisation for Animal Health (OIE) and the Food and Agriculture Organisation (FAO) for eradication with the aim of global elimination of the disease by 2030. Fundamentally, the vaccines required to successfully achieve this goal are currently available, but the availability of novel vaccine preparations to also fulfill the requisite for differentiation between infected and vaccinated animals (DIVA) may reduce the time taken and the financial costs of serological surveillance in the later stages of any eradication campaign. Here, we overview what is currently known about the virus, with reference to its origin, updated global circulation, molecular evolution, diagnostic tools and vaccines currently available to combat the disease. Further, we comment on recent developments in our knowledge of various recombinant vaccines and on the potential for the development of novel multivalent vaccines for small ruminants.

  13. Peste des petits ruminants

    PubMed Central

    Parida, S.; Muniraju, M.; Mahapatra, M.; Muthuchelvan, D.; Buczkowski, H.; Banyard, A.C.

    2015-01-01

    Peste des petits ruminants virus causes a highly infectious disease of small ruminants that is endemic across Africa, the Middle East and large regions of Asia. The virus is considered to be a major obstacle to the development of sustainable agriculture across the developing world and has recently been targeted by the World Organisation for Animal Health (OIE) and the Food and Agriculture Organisation (FAO) for eradication with the aim of global elimination of the disease by 2030. Fundamentally, the vaccines required to successfully achieve this goal are currently available, but the availability of novel vaccine preparations to also fulfill the requisite for differentiation between infected and vaccinated animals (DIVA) may reduce the time taken and the financial costs of serological surveillance in the later stages of any eradication campaign. Here, we overview what is currently known about the virus, with reference to its origin, updated global circulation, molecular evolution, diagnostic tools and vaccines currently available to combat the disease. Further, we comment on recent developments in our knowledge of various recombinant vaccines and on the potential for the development of novel multivalent vaccines for small ruminants. PMID:26443889

  14. Elimination of early rehospitalization in a randomized, controlled trial of multidisciplinary care in a high-risk, elderly heart failure population: the potential contributions of specialist care, clinical stability and optimal angiotensin-converting enzyme inhibitor dose at discharge.

    PubMed

    McDonald, K; Ledwidge, M; Cahill, J; Kelly, J; Quigley, P; Maurer, B; Begley, F; Ryder, M; Travers, B; Timmons, L; Burke, T

    2001-03-01

    Despite a growing body of data demonstrating the benefits of multidisciplinary care in heart failure, persistently high rates of readmission, especially within the first month of discharge, continue to be documented. As part of an ongoing randomized study on the value of multidisciplinary care in a high risk (NYHA Class IV), elderly (mean age 69 years) heart failure population, we examined the effects of this intervention on previously high (20%) 1-month readmission rates. Unlike previous studies of this approach, both multidisciplinary (MC) and routine care (RC) populations were cared for by the cardiology service, complied with adherence to clinical stability criteria prior to discharge (100% of patients) and received at least target dose angiotensin-converting enzyme (ACE) inhibition with perindopril prior to discharge (94% of indicated patients). We analysed death and unplanned readmission for heart failure at 1 month. This early report from the first 70 patients (67% male, 71% systolic dysfunction with a mean ejection fraction of 31.0+/-6.7%) enrolled in this study demonstrates elimination of 1-month hospital readmission in both RC and MC groups. This unexpected result represents a dramatic improvement both for this patient cohort (20% 30-day readmission rate prior to enrollment reduced to 0% following the index admission in both care groups) and in comparison with available data. Critical contributors to this improvement appear to be specialist cardiology care, adherence to clinical stability criteria prior to discharge and routine use of target or high-dose ACE inhibitor therapy prior to discharge. Widespread application of this approach may have a dramatic improvement in morbidity of CHF while limiting the escalating costs of this condition.

  15. Acute kidney failure

    MedlinePlus

    Kidney failure; Renal failure; Renal failure - acute; ARF; Kidney injury - acute ... There are many possible causes of kidney damage. They include: ... cholesterol (cholesterol emboli) Decreased blood flow due to very ...

  16. What Is Heart Failure?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Is Heart Failure? Heart failure is a condition in which the heart can' ... force. Some people have both problems. The term "heart failure" doesn't mean that your heart has stopped ...

  17. Heart failure - medicines

    MedlinePlus

    CHF - medicines; Congestive heart failure - medicines; Cardiomyopathy - medicines; HF - medicines ... You will need to take most of your heart failure medicines every day. Some medicines are taken ...

  18. Intracoronary brachytherapy following drug-eluting stent failure It's still not time to hang up the spikes{exclamation_point}

    SciTech Connect

    Angiolillo, Dominick J.; Sabate, Manel; Jimenez-Quevedo, Pilar; Alfonso, Fernando; Galvan, Carmen; Fernandez, Jose Miguel; Hernandez-Antolin, Rosana; Escaned, Javier; Banuelos, Camino; Moreno, Raul; Macaya, Carlos

    2003-12-01

    Drug-eluting stents (DES) have significantly reduced the incidence of restenosis. Although the results obtained with these novel antiproliferative devices are encouraging, recent reports have shown that DES are not completely immune from restenosis. Therefore, the broad use of DES has inevitably led to a major issue: treatment of DES failure. Intracoronary brachytherapy (IBT) represents an important advancement for treatment of in-stent restenosis (ISR) and has led to important pathophysiological insight on the restenotic process. To date, IBT, when properly used, still represents the gold standard for treatment of ISR. However, experience with IBT is for treatment of ISR occurring with bare metal stents (BMS). Whether IBT may be used with the same safety and efficacy profile as an adjunctive treatment for ISR following DES implantation is still unknown. In this article, we report the outcome of a series of patients with DES failure treated with IBT. IBT for treatment of DES failure was shown to be both safe and efficient and, therefore, until ISR exists, IBT still remains an important player in this growing and even more challenging setting.

  19. Heart failure - surgeries and devices

    MedlinePlus

    CHF - surgery; Congestive heart failure - surgery; Cardiomyopathy - surgery; HF - surgery; Intra-aortic balloon pumps - heart failure; IABP - heart failure; Catheter based assist devices - heart failure

  20. Epidemiology of anemia in heart failure.

    PubMed

    Tang, W H Wilson; Yeo, P S Daniel

    2010-07-01

    Anemia is being increasingly recognized as an important comorbidity in patients with heart failure. Despite wide variations in defining anemia, approximately one-fifth to one-third of patients with heart failure may experience anemia at a given time. The prevalence may increase to more than half of patients in the setting of severe heart failure, and it may differ with different settings. Meanwhile, up to a fifth of patients may experience new-onset anemia, even though most cases may resolve over time. Different factors contribute to the development of anemia, including increasing age, renal insufficiency, hemodilution, chronic inflammation, and increasing heart failure disease severity.

  1. Etude des Abondances de MG et de fe dans la Composante Stellaire des Disques des Galaxies Spirales

    NASA Astrophysics Data System (ADS)

    Beauchamp, Dominique

    Je presente ici une technique d'observation par imagerie des disques stellaires des galaxies spirales. Je tente, a l'aide d'un modele evolutif multiphase, de determiner les abondances de fer et de magnesium dans les disques. Dans ce but, je mesure les indices Mg2 et Fe5270 du systeme de Lick. Ces elements representent un choix judicieux d'indicateurs car ils sont formes par des supernovae de deux types differents ayant des durees de vie differentes. Le rapport d'abondances de ces deux elements est un indicateur du taux de formation des populations stellaires. Je decris, en premier lieu, les observations, la technique de mesure, ainsi que son application. J'analyse ensuite les indices mesures. A partir du modele multiphase, j'explore differents parametres physiques des spirales comme le taux de formation stellaire, l'evolution des abondances, les effets possibles de la presence de la barre, etc.

  2. High Technology Systems with Low Technology Failures: Some Experiences with Rockets on Software Quality and Integration

    NASA Technical Reports Server (NTRS)

    Craig, Larry G.

    2010-01-01

    This slide presentation reviews three failures of software and how the failures contributed to or caused the failure of a launch or payload insertion into orbit. In order to avoid these systematic failures in the future, failure mitigation strategies are suggested for use.

  3. Classification of 17 DES supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Mudd, D.; Martini, P.; Lewis, G. F.; Moller, A.; Sharp, R. G.; Sommer, N. E.; Tucker, B. E.; Yuan, F.; Zhang, B.; Asorey, J.; Davis, T. M.; Hinton, S.; Muthukrishna, D.; Parkinson, D.; Carnero, A.; King, A.; Lidman, C.; Webb, S.; Uddin, S.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; D'Andrea, C.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Macaulay, E.; Nichol, R.; Childress, M.; Prajs, S.; Smith, M.; Sullivan, M.; Maartens, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Gupta, R.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Papadopoulos, A.; Morganson, E.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.

    2016-11-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  4. Classification of 17 DES supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Muthukrishna, D.; Sharp, R. G.; Tucker, B. E.; Moller, A.; Sommer, N. E.; Asorey, J.; Lewis, G. F.; Lidman, C.; Mould, J.; Macaulay, E.; Maartens, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Gupta, R.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Papadopoulos, A.; Morganson, E.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Yuan, F.; Zhang, B.; Davis, T. M.; Hinton, S.; Parkinson, D.; Uddin, S.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; D'Andrea, C.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Childress, M.; Prajs, S.; Smith, M.; Sullivan, M.

    2017-09-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  5. Classification of 3 DES Supernovae with OzDES

    NASA Astrophysics Data System (ADS)

    Moller, A.; Tucker, B. E.; Yuan, F.; Lewis, G.; Lidman, C.; Macaulay, E.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.

    2016-02-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  6. Classification of 20 DES Supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Davis, T. M.; Kim, A. G.; Macualay, E.; Lidman, C.; Sharp, R.; Tucker, B. E.; Yuan, F.; Zhang, B.; Lewis, G. F.; Sommer, N. E.; Martini, P.; Mould, J.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.

    2015-12-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  7. Classification of 14 DES Supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Tucker, B. E.; Sharp, R.; Yuan, F.; Zhang, B.; Lidman, C.; Davis, T. M.; Hinton, S.; Mould, J.; Smith, R. C.; Schubnell, M.; Kessler, R.; Scolnic, D.; Covarrubias, R. A.; Brout, D. J.; Fischer, J. A.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; D'Andrea, C.; Smith, M.; Sullivan, M.; Childress, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Castander, F. J.; Desai, S.; Paech, K.

    2015-10-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey. The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  8. Classification of 4 DES supernovae by OzDES

    NASA Astrophysics Data System (ADS)

    Glazebrook, K.; Amon, A.; Lidman, C.; Martini, P.; Tucker, B. E.; Yuan, F.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.

    2015-12-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  9. Classification of 6 DES Supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Lewis, G. F.; Mould, J.; Lidman, C.; Tucker, B. E.; Sharp, R.; Yuan, F.; Martini, P.; Kessler, R.; Scolnic, D.; Covarrubias, R. A.; Brout, D. J.; Fischer, J. A.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; D'Andrea, C.; Smith, M.; Sullivan, M.; Childress, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.

    2015-10-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  10. Classification of 15 DES supernovae by OzDES

    NASA Astrophysics Data System (ADS)

    Yuan, F.; Tucker, B. E.; Lidman, C.; Martini, P.; Gshwend, Julia; Moller, A.; Zhang, B.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.

    2015-12-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  11. Classification of 8 DES Supernova with OzDES

    NASA Astrophysics Data System (ADS)

    King, A.; Moller, A.; Sommer, N. E.; Tucker, B. E.; Childress, M. J.; Lewis, G. F.; Lidman, C.; OâNeill, C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; D'Andrea, C.; Prajs, S.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.

    2016-09-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  12. Classification of 17 DES Supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Hoormann, J. K.; Asorey, J.; Carollo, D.; Moller, A.; Sharp, R.; Sommer, N. E.; Tucker, B. E.; Zhang, B.; Lidman, C.; Brout, D. J.; D'Andrea, C.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Macaulay, E.; Nichol, R.; Childress, M.; Prajs, S.; Smith, M.; Sullivan, M.; Maartens, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Gupta, R.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Papadopoulos, A.; Morganson, E.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Yuan, F.; Davis, T. M.; Hinton, S.; Muthukrishna, D.; Parkinson, D.; Lewis, G. F.; Uddin, S.; Kessler, R.; Lasker, J.; Scolnic, D.

    2016-12-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  13. Classification of 13 DES supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Sommer, N.; Tucker, B. E.; Moller, A.; Zhang, B.; Macualay, E.; Lidman, C.; Gshwend, J.; Martini, P.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; Gladney, L.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Nichol, R.; Papadopoulos, A.; Childress, M.; D'Andrea, C.; Prajs, S.; Smith, M.; Sullivan, M.; Maartens, R.; Gupta, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.

    2016-09-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  14. Classification of 11 DES supernova with OzDES

    NASA Astrophysics Data System (ADS)

    Sharp, R.; Zhang, B.; Sommer, N. E.; Tucker, B. E.; Lidman, C.; Davis, T. M.; Asorey, J.; Mould, J.; Smith, M.; Macaulay, E.; Nichol, R.; Childress, M.; Prajs, S.; Sullivan, M.; Maartens, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Gupta, R.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Papadopoulos, A.; Morganson, E.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Carollo, D.; Moller, A.; Yuan, F.; Hinton, S.; Muthukrishna, D.; Parkinson, D.; Lewis, G. F.; Uddin, S.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; D'Andrea, C.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.

    2017-01-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  15. Classification of 2 DES supernova with OzDES

    NASA Astrophysics Data System (ADS)

    O'Neill, C. R.; Moller, A.; Sommer, N. E.; Tucker, B. E.; Childress, M. J.; Lewis, G. F.; Lidman, C.; Desai, S.; Paech, K.; Smith, R. C.; Schubnell, M.; Kessler, R.; Lasker, J.; Scolnic, D.; Brout, D. J.; D'Andrea, C.; Gladney, L.; March, M.; Sako, M.; Wolf, R. C.; Brown, P. J.; Krisciunas, K.; Suntzeff, N.; Macaulay, E.; Nichol, R.; Prajs, S.; Smith, M.; Sullivan, M.; Maartens, R.; Kovacs, E.; Kuhlmann, S.; Spinka, H.; Ahn, E.; Finley, D. A.; Frieman, J.; Marriner, J.; Wester, W.; Aldering, G.; Kim, A. G.; Thomas, R. C.; Barbary, K.; Bloom, J. S.; Goldstein, D.; Gupta, R.; Nugent, P.; Perlmutter, S.; Foley, R. J.; Pan, Y.-C.; Casas, R.; Castander, F. J.; Papadopoulos, A.; Morganson, E.

    2016-10-01

    We report new spectroscopic classifications by OzDES of supernovae discovered by the Dark Energy Survey (ATEL #4668). The spectra (370-885nm) were obtained with the AAOmega Spectrograph (Saunders et al. 2004, SPIE, 5492, 389) and the 2dF fibre positioner at the Anglo-Australian Telescope (AAT).

  16. Understanding Cytokinesis Failure

    PubMed Central

    Normand, Guillaume; King, Randall W.

    2011-01-01

    Cytokinesis is the final step in cell division. The process begins during chromosome segregation, when the ingressing cleavage furrow begins to partition the cytoplasm between the nascent daughter cells. The process is not completed until much later, however, when the final cytoplasmic bridge connecting the two daughter cells is severed. Cytokinesis is a highly ordered process, requiring an intricate interplay between cytoskeletal, chromosomal, and cell cycle regulatory pathways. A surprisingly broad range of additional cellular processes are also important for cytokinesis, including protein and membrane trafficking, lipid metabolism, protein synthesis and signaling pathways. As a highly regulated, complex process, it is not surprising that cytokinesis can sometimes fail. Cytokinesis failure leads to both centrosome amplification and production of tetraploid cells, which may set the stage for the development of tumor cells. However, tetraploid cells are abundant components of some normal tissues including liver and heart, indicating that cytokinesis is physiologically regulated. In this chapter, we summarize our current understanding of the mechanisms of cytokinesis, emphasizing steps in the pathway that may be regulated or prone to failure. Our discussion emphasizes findings in vertebrate cells although we have attempted to highlight important contributions from other model systems. PMID:20687468

  17. Thyroid hormones and heart failure.

    PubMed

    Martinez, Felipe

    2016-07-01

    Heart failure is a major health problem and its relationship to thyroid dysfunction has been increasingly investigated in recent years. Since it has been demonstrated that thyroid hormones (TH) and mainly T3 have cardioprotective effects, it is easy to understand that in the scenario of thyroid disorder, cardiac function may be damaged, and inversely in cardiac dysfunction thyroid dysregulation may be seen. The increase in plasma TH produces a clear neurohormonal activation which impacts negatively on cardiac function. In hypothyroidism, and in addition to extracardiac dysfunction, myocardial and vascular remodelling is altered and they contribute to cardiac failure. Abnormal low plasma TSH has also been shown to be a risk factor for developing HF in several recent studies, and they suggest that TSH is an independent predictor of clinical outcome including death and cardiac hospitalizations. Therefore, physicians should consider all these concepts when managing a patient with heart failure, not only for a clear diagnosis, but also for better and accurate treatment.

  18. The lived experience of NCLEX failure.

    PubMed

    Griffiths, Margaret J; Papastrat, Karen; Czekanski, Kathleen; Hagan, Kevin

    2004-07-01

    Educators help coach, focus, and prepare students for the National Council Licensure Examination (NCLEX), but often fall short in providing support when graduates are not successful. Most research to date has focused solely on predicting failure, with little to no attention given to interventions after failure. This study presents the voices of unsuccessful candidates, their responses to failure, their perspectives of the factors that contributed to their failure, and the changes they made that led to subsequent success. The results demonstrate common themes related to the failure experience, successful remediation strategies for retesting, and recommendations for faculty interventions during this vulnerable period. Nurse educators have a responsibility to identify, inform, and intervene with students who are at high risk of failing the NCLEX, and this responsibility is executed capably. However, the role extends beyond graduation. The responsibility to help nursing graduates transition from failure to licensure is the final step of successful undergraduate nursing education.

  19. Heart Failure and Loss of Metabolic Control

    PubMed Central

    Wang, Zhao V.; Li, Dan L.; Hill, Joseph A.

    2014-01-01

    Heart failure is a leading cause of morbidity and mortality worldwide, currently affecting 5 million Americans. A syndrome defined on clinical terms, heart failure is the end-result of events occurring in multiple heart diseases, including hypertension, myocardial infarction, genetic mutations and diabetes, and metabolic dysregulation is a hallmark feature. Mounting evidence from clinical and preclinical studies suggests strongly that fatty acid uptake and oxidation are adversely affected, especially in end-stage heart failure. Moreover, metabolic flexibility, the heart’s ability to move freely among diverse energy substrates, is impaired in heart failure. Indeed, impairment of the heart’s ability to adapt to its metabolic milieu, and associated metabolic derangement, are important contributing factors in heart failure pathogenesis. Elucidation of molecular mechanisms governing metabolic control in heart failure will provide critical insights into disease initiation and progression, raising the prospect of advances with clinical relevance. PMID:24336014

  20. Latina Voices of Des Moines.

    ERIC Educational Resources Information Center

    Taylor, P. Dawn

    This dissertation examines the lives of Hispanic women living in Des Moines and includes their views of problems and opportunities involved in living in that city. Interviews were conducted with 24 Latino women over the age of 17 who had been in the area for over 2 years. Findings indicate that learning to speak English was the single most…

  1. Insulin Signaling and Heart Failure.

    PubMed

    Riehle, Christian; Abel, E Dale

    2016-04-01

    Heart failure is associated with generalized insulin resistance. Moreover, insulin-resistant states such as type 2 diabetes mellitus and obesity increases the risk of heart failure even after adjusting for traditional risk factors. Insulin resistance or type 2 diabetes mellitus alters the systemic and neurohumoral milieu, leading to changes in metabolism and signaling pathways in the heart that may contribute to myocardial dysfunction. In addition, changes in insulin signaling within cardiomyocytes develop in the failing heart. The changes range from activation of proximal insulin signaling pathways that may contribute to adverse left ventricular remodeling and mitochondrial dysfunction to repression of distal elements of insulin signaling pathways such as forkhead box O transcriptional signaling or glucose transport, which may also impair cardiac metabolism, structure, and function. This article will review the complexities of insulin signaling within the myocardium and ways in which these pathways are altered in heart failure or in conditions associated with generalized insulin resistance. The implications of these changes for therapeutic approaches to treating or preventing heart failure will be discussed.

  2. Insulin Signaling and Heart Failure

    PubMed Central

    Riehle, Christian; Abel, E. Dale

    2016-01-01

    Heart failure is associated with generalized insulin resistance. Moreover, insulin resistant states such as type 2 diabetes and obesity increases the risk of heart failure even after adjusting for traditional risk factors. Insulin resistance or type 2 diabetes alters the systemic and neurohumoral milieu leading to changes in metabolism and signaling pathways in the heart that may contribute to myocardial dysfunction. In addition, changes in insulin signaling within cardiomyocytes develop in the failing heart. The changes range from activation of proximal insulin signaling pathways that may contribute to adverse left ventricular remodeling and mitochondrial dysfunction to repression of distal elements of insulin signaling pathways such as forkhead (FOXO) transcriptional signaling or glucose transport which may also impair cardiac metabolism, structure and function. This article will review the complexities of insulin signaling within the myocardium and ways in which these pathways are altered in heart failure or in conditions associated with generalized insulin resistance. The implications of these changes for therapeutic approaches to treating or preventing heart failure will be discussed. PMID:27034277

  3. L'astronomie des Anciens

    NASA Astrophysics Data System (ADS)

    Nazé, Yaël

    2009-04-01

    Quelle que soit la civilisation à laquelle il appartient, l'être humain cherche dans le ciel des réponses aux questions qu'il se pose sur son origine, son avenir et sa finalité. Le premier mérite de ce livre est de nous rappeler que l'astronomie a commencé ainsi à travers les mythes célestes imaginés par les Anciens pour expliquer l'ordre du monde et la place qu'ils y occupaient. Mais les savoirs astronomiques passés étaient loin d'être négligeables et certainement pas limités aux seuls travaux des Grecs : c'est ce que l'auteur montre à travers une passionnante enquête, de Stonehenge à Gizeh en passant par Pékin et Mexico, fondée sur l'étude des monuments anciens et des sources écrites encore accessibles. Les tablettes mésopotamiennes, les annales chinoises, les chroniques médiévales, etc. sont en outre d'une singulière utilité pour les astronomes modernes : comment sinon remonter aux variations de la durée du jour au cours des siècles, ou percer la nature de l'explosion qui a frappé tant d'observateurs en 1054 ? Ce livre offre un voyage magnifiquement illustré à travers les âges, entre astronomie et archéologie.

  4. Multistatic Surveillance and Reconnaissance: Sensor, Signals and Data Fusion (Surveillance et Reconnaissance Multistatiques : Fusion des capteurs, des signaux et des donnees)

    DTIC Science & Technology

    2009-04-01

    capteurs , des signaux et des données) Research and Technology Organisation (NATO) BP 25, F-92201 Neuilly-sur-Seine Cedex, France RTO-EN-SET-133...Multistatiques : Fusion des capteurs , des signaux et des données) The material in this publication was assembled to support a Lecture Series under the...Surveillance et Reconnaissance Multistatiques : Fusion des capteurs , des signaux et des données (RTO-EN-SET-133) Synthèse Les systèmes radar

  5. Supergroupes de Lie et solutions invariantes pour des equations differentielles non-lineaires a valeurs de Grassmann

    NASA Astrophysics Data System (ADS)

    Ayari, Mohamed Ali

    Le present travail est une contribution a l'etude des equations aux derivees partielles a valeurs de Grassmann (superequations) qui constituent une extension des equations usuelles en ce sens qu'elles contiennent en plus des variables dependantes et independantes anticommutantes (fermioniques). Nous nous sommes d'abord poses la question de savoir comment generaliser la notion de groupe de Lie de symetrie de telles superequations. En effet, de telles equations etant souvent supersymetriques, elles englobent une symetrie plus large que les equations usuelles. Ensuite, nous avons utilise la methode de reduction par symetrie pour donner des solutions explicites. Nous nous sommes attardes plus specifiquement sur la superequation de KdV (N = 2) qui apparai t comme la version supersymetrique des equations de KdV et KdV modifiee. Calculer la superalgebre de Lie de symetrie d'un supersysteme est une tache tres lourde qui depend de l'ordre et du nombre de variables dependantes et independantes. Afin de surmonter ce probleme algorithmique, nous avons realise une premiere version d'un code appele GLie permettant non seulement le calcul des superequations determinantes des systemes d'equations differentielles a valeurs de Grassmann mais aussi des equations aux derivees partielles usuelles. Ce programme ecrit dans le langage Maple permet d'economiser le temps et d'echapper aux inevitables erreurs de calculs.

  6. A retrospective pilot study: management of patients with heart failure.

    PubMed

    Ancheta, Irma B

    2006-01-01

    An epidemic disease - a major cause of chronic disability - congestive heart failure adversely affects the health of millions. Congestive heart failure is the most frequent cause of cardiovascular hospital admissions and shares a significant responsibility for the high cost of healthcare. Despite medical and technological advances, studies show that the treatment of heart failure is suboptimal. Physician knowledge and awareness of appropriate treatment may contribute to patient compliance and improve delivery of healthcare. The purpose of this article is to examine how patients with heart failure in a heart failure clinic are managed. Recommendations are proposed and the role of nurses and clinicians in heart failure management is discussed.

  7. Recognition Failure: Another Case of Retrieval Failure

    ERIC Educational Resources Information Center

    Rabinowitz, Jan; And Others

    1977-01-01

    A theoretical explanation of the phenomenon of recognition failure and a presentation of seven experiments investigating performance. Recognition failure is reduced when a more stringent recognition criterion is used, essentially eliminated when the proper access test is used and significantly reduced when variability in recognition performance is…

  8. Contribution à la modélisation du soudage TIG des tôles minces d'acier austénitique 304L par un modèle source bi-elliptique, avec confrontation expérimentale

    NASA Astrophysics Data System (ADS)

    Aissani, M.; Maza, H.; Belkessa, B.; Maamache, B.

    2005-05-01

    Ce travail contribue dans la modélisation du phénomène du soudage de l'acier inoxydable Austénitique 304L, afin d'étudier le comportement thermique d'un joint de soudure, obtenu par le procédé de soudage à l'arc électrique TIG (Tungsten-Inert-Gas). Le modèle simulant la source d'énergie de soudage, utilise une distribution surfacique Gaussienne du flux de chaleur provenant de l'arc électrique. La forme de cette source est supposée circulaire pour un premier cas et de forme bi-elliptique pour un second cas, tout en procédant à l'évaluation des champs et cycles thermiques à chaque instant, pour déterminer l'étendu des zones à risque, et l'effet de la vitesse de soudage sur ces dernières. Permettant ainsi de remonter par la suite, aux problèmes de contraintes résiduelles et déformations générées dans l'assemblage soudé. L'équation de chaleur régissant le problème est discrétisée par la méthode des volumes finis. Les calculs sont effectués en considérant que les propriétés physiques et thermiques ainsi que les conditions aux limites de convection et rayonnement, sont dépendante de la température. Pour évaluer la précision du modèle, une comparaison avec des mesures expérimentales de température d'un essai de soudage a été effectuée, les résultats indiquent un bon accord.

  9. The role of ultrafiltration in the management of heart failure.

    PubMed

    Costanzo, Maria Rosa

    2008-01-01

    Congestion causes the majority of hospitalizations for heart failure and contributes to heart failure progression and mortality. Intravenous loop diuretics reduce the signs and symptoms of congestion. Loop diuretics, however, may be associated with increased morbidity and mortality due to deleterious effects on neurohormonal activation, electrolyte balance, and cardiac and renal function. Ultrafiltration, an alternative method of sodium and water removal, safely improves hemodynamics in heart failure patients. Recent clinical trial data suggest that ultrafiltration may also reduce rehospitalizations for worsening heart failure.

  10. Signature spectrale des grains interstellaires.

    NASA Astrophysics Data System (ADS)

    Léger, A.

    Notre connaissance de la nature des grains interstellaires reposait sur un nombre très restreint de signatures spectrales dans la courbe d'extinction du milieu interstellaire. Une information considérable est contenue dans les 40 bandes interstellaires diffuses dans le visible, mais reste inexploitée. L'interprétation récente des cinq bandes IR en émission, en terme de molécules d'hydrocarbures aromatiques polycycliques, est développée. Elle permet l'utilisation d'une information spectroscopique comparable, à elle seule, à ce sur quoi était basée jusqu'alors notre connaissance de la matière interstellaire condensée. Différentes implications de cette mise en évidence sont proposées.

  11. Failure in glass

    NASA Technical Reports Server (NTRS)

    Keeton, S. C.

    1972-01-01

    Review of state of the art concerning glass failure mechanisms and fatigue theories discusses brittle fracture in glass, fatigue mechanisms, fatigue behavior, environmental effects on failure rate, and aging.

  12. [Understanding heart failure].

    PubMed

    Boo, José Fernando Guadalajara

    2006-01-01

    Heart failure is a disease with several definitions. The term "heart failure" is used by has brougth about confusion in the terminology. For this reason, the value of the ejection fraction (< 0.40 or < 0.35) is used in most meganalyses on the treatment of heart failure, avoiding the term "heart failure" that is a confounding concept. In this paper we carefully analyze the meaning of contractility, ventricular function or performance, preload, afterload, heart failure, compensation mechanisms in heart failure, myocardial oxygen consumption, inadequate, adequate and inappropriate hypertrophy, systole, diastole, compliance, problems of relaxation, and diastolic dysfunction. Their definitions are supported by the original scientific descriptions in an attempt to clarify the concepts about ventricular function and heart failure and, in this way, use the same scientific language about the meaning of ventricular function, heart failure, and diastolic dysfunction.

  13. Loess failure in northeast Afghanistan

    NASA Astrophysics Data System (ADS)

    Shroder, John F.; Schettler, Megan Jensen; Weihs, Brandon J.

    Mass movements in northeastern Afghanistan include large-scale rockslides and complex slope failures, as well as failures in loess. The loess region in northeastern Afghanistan occurs in the Badakhshan and Takhar provinces and was likely created by dust blown to the east from the Karakum Desert and the alluvial plains of northern Afghanistan. This loessic dust was deposited against the Hindu Kush mountain range which rises up along the eastern half of Afghanistan as a result of transpressional tectonism. It overlies less permeable crystalline and sedimentary bedrocks such as Triassic granite, Proterozoic gneiss, and Miocene and Pliocene clastics in the area with the largest concentration of slope failures. Thirty-four loess slides and flows were mapped and analyzed using remote satellite imagery over digital elevation models on Google Earth™. This source enabled location, classification, and measurement of failures. Findings revealed that most failed slopes faced north, west, and northwest. This trend can be explained possibly as different moisture contents resulting from the primarily westerly wind direction, which may cause more precipitation to be deposited on west-facing slopes, and sun position during the hottest part of the day. Additionally, the easterly rising Hindu Kush range may cause more slope area to face west in the study region. Other contributing factors could be the very high seismicity of the area, which may cause rapid dry fluidized loess flows, and landscape modification by humans. Several loess slope failures appear to be generated by water concentration through irrigation ditches and possible rutted tire tracks, which can create tunneling between the loess and its less permeable bedrock. Causes and effects of loess failure in Afghanistan need to be investigated in more depth. Further study may lead to the adoption of more sustainable and safe farming practices and more informed housing locations, which may prevent loss of property, crop, and

  14. Failures in psychodynamic psychotherapy.

    PubMed

    Gold, Jerry; Stricker, George

    2011-11-01

    This article addresses the issue of failures in psychodynamic psychotherapy. Drawing on the clinical and research literatures, and utilizing our clinical experiences, we first describe and define criteria for success and failure in treatment. We then review five factors that can lead to failure: client factors, therapist factors, technical factors, relationship factors, and environmental factors. We illustrate our presentation with a case example, and conclude by discussing ways in which the likelihood of failures in psychodynamic treatment can be lowered.

  15. Failure analysis of high performance ballistic fibers

    NASA Astrophysics Data System (ADS)

    Spatola, Jennifer S.

    High performance fibers have a high tensile strength and modulus, good wear resistance, and a low density, making them ideal for applications in ballistic impact resistance, such as body armor. However, the observed ballistic performance of these fibers is much lower than the predicted values. Since the predictions assume only tensile stress failure, it is safe to assume that the stress state is affecting fiber performance. The purpose of this research was to determine if there are failure mode changes in the fiber fracture when transversely loaded by indenters of different shapes. An experimental design mimicking transverse impact was used to determine any such effects. Three different indenters were used: round, FSP, and razor blade. The indenter height was changed to change the angle of failure tested. Five high performance fibers were examined: KevlarRTM KM2, SpectraRTM 130d, DyneemaRTM SK-62 and SK-76, and ZylonRTM 555. Failed fibers were analyzed using an SEM to determine failure mechanisms. The results show that the round and razor blade indenters produced a constant failure strain, as well as failure mechanisms independent of testing angle. The FSP indenter produced a decrease in failure strain as the angle increased. Fibrillation was the dominant failure mechanism at all angles for the round indenter, while through thickness shearing was the failure mechanism for the razor blade. The FSP indenter showed a transition from fibrillation at low angles to through thickness shearing at high angles, indicating that the round and razor blade indenters are extreme cases of the FSP indenter. The failure mechanisms observed with the FSP indenter at various angles correlated with the experimental strain data obtained during fiber testing. This indicates that geometry of the indenter tip in compression is a contributing factor in lowering the failure strain of the high performance fibers. TEM analysis of the fiber failure mechanisms was also attempted, though without

  16. Alcohol based-deep eutectic solvent (DES) as an alternative green additive to increase rotenone yield

    SciTech Connect

    Othman, Zetty Shafiqa; Hassan, Nur Hasyareeda; Zubairi, Saiful Irwan

    2015-09-25

    Deep eutectic solvents (DESs) are basically molten salts that interact by forming hydrogen bonds between two added components at a ratio where eutectic point reaches a melting point lower than that of each individual component. Their remarkable physicochemical properties (similar to ionic liquids) with remarkable green properties, low cost and easy handling make them a growing interest in many fields of research. Therefore, the objective of pursuing this study is to analyze the potential of alcohol-based DES as an extraction medium for rotenone extraction from Derris elliptica roots. DES was prepared by a combination of choline chloride, ChCl and 1, 4-butanediol at a ratio of 1/5. The structure of elucidation of DES was analyzed using FTIR, {sup 1}H-NMR and {sup 13}C-NMR. Normal soaking extraction (NSE) method was carried out for 14 hours using seven different types of solvent systems of (1) acetone; (2) methanol; (3) acetonitrile; (4) DES; (5) DES + methanol; (6) DES + acetonitrile; and (7) [BMIM] OTf + acetone. Next, the yield of rotenone, % (w/w), and its concentration (mg/ml) in dried roots were quantitatively determined by means of RP-HPLC. The results showed that a binary solvent system of [BMIM] OTf + acetone and DES + acetonitrile was the best solvent system combination as compared to other solvent systems. It contributed to the highest rotenone content of 0.84 ± 0.05% (w/w) (1.09 ± 0.06 mg/ml) and 0.84 ± 0.02% (w/w) (1.03 ± 0.01 mg/ml) after 14 hours of exhaustive extraction time. In conclusion, a combination of the DES with a selective organic solvent has been proven to have a similar potential and efficiency as of ILs in extracting bioactive constituents in the phytochemical extraction process.

  17. Alcohol based-deep eutectic solvent (DES) as an alternative green additive to increase rotenone yield

    NASA Astrophysics Data System (ADS)

    Othman, Zetty Shafiqa; Hassan, Nur Hasyareeda; Zubairi, Saiful Irwan

    2015-09-01

    Deep eutectic solvents (DESs) are basically molten salts that interact by forming hydrogen bonds between two added components at a ratio where eutectic point reaches a melting point lower than that of each individual component. Their remarkable physicochemical properties (similar to ionic liquids) with remarkable green properties, low cost and easy handling make them a growing interest in many fields of research. Therefore, the objective of pursuing this study is to analyze the potential of alcohol-based DES as an extraction medium for rotenone extraction from Derris elliptica roots. DES was prepared by a combination of choline chloride, ChCl and 1, 4-butanediol at a ratio of 1/5. The structure of elucidation of DES was analyzed using FTIR, 1H-NMR and 13C-NMR. Normal soaking extraction (NSE) method was carried out for 14 hours using seven different types of solvent systems of (1) acetone; (2) methanol; (3) acetonitrile; (4) DES; (5) DES + methanol; (6) DES + acetonitrile; and (7) [BMIM] OTf + acetone. Next, the yield of rotenone, % (w/w), and its concentration (mg/ml) in dried roots were quantitatively determined by means of RP-HPLC. The results showed that a binary solvent system of [BMIM] OTf + acetone and DES + acetonitrile was the best solvent system combination as compared to other solvent systems. It contributed to the highest rotenone content of 0.84 ± 0.05% (w/w) (1.09 ± 0.06 mg/ml) and 0.84 ± 0.02% (w/w) (1.03 ± 0.01 mg/ml) after 14 hours of exhaustive extraction time. In conclusion, a combination of the DES with a selective organic solvent has been proven to have a similar potential and efficiency as of ILs in extracting bioactive constituents in the phytochemical extraction process.

  18. Annuaire du Bureau des longitudes - 2006

    NASA Astrophysics Data System (ADS)

    Imcce; Bureau Des Longitudes

    2005-07-01

    This annual publication provides ephemerides and data to the use of professionnal and amateur astronomers. Divided in 11 chapters it covers concordance of various calendars, explanation of fondamental astronomy and various time scales, explanation for the use of ephemerides; tables provide ephemerides (positions, rise/set/passage) of the Sun and the Moon, planets, planetary satellites, asteroids, comets, bright stars; data and explanation for the physical observation of the surface of the Sun, the Moon, and planets; chart of the sky and a list of constellations and galaxies; prediction and ephemerides for astronomical phenomenon: occultation by the moon, stellar occultations by asteroids and appulses, solar eclipses and lunar eclipses; and an additional review about a hot scientific topic, this year: "Legendre et le méridien terrestre, 200 ans après". Cette publication annuelle fournit des éphémérides et des données à l'usage des astronomes professionnels et des astronomes amateurs. Composée de 11 chapitres elle comprend les rubriques sur les différents calendriers et leurs concordance, les fêtes légales en France, les dates et décrets sur les heures légales en France métropolitaine ; une introduction à l'astronomie fondamentale et aux différentes échelles de temps, des explications sur l'utilisation des éphémérides ; des tables fournissent les éphémérides (positions, heures de lever/coucher/passage) du Soleil et de la Lune, de planètes, de satellites naturels, d'astéroïdes, de comètes, d'étoiles brillantes ; des données pour l'observation de la surface du Soleil, de la Lune, et des planètes ; des cartes du ciel ainsi qu'une liste de constellations et de galaxies ; des prédictions des phénomènes astronomiques : occultation par la Lune, occultation stellaires par des astéroïdes et appulses, éclipses de Soleil et de la Lune; la liste et les coordonnées des observatoires astronomiques les plus connus ; et enfin un cahier th

  19. Ammonia tank failure

    SciTech Connect

    Sweat, M.E.

    1983-04-01

    An ammonia tank failure at Hawkeye Chemical of Clinton, Iowa is discussed. The tank was a double-wall, 27,000 metric-ton tank built in 1968 and commissioned in December 1969. The paper presented covers the cause of the failure, repair, and procedural changes made to prevent recurrence of the failure. (JMT)

  20. Heart failure - palliative care

    MedlinePlus

    Chronic heart failure very often gets worse over time. Many people who have heart failure die of ... failure to take in enough calories and nutrients. Wasting of muscles and weight loss are part of the natural disease process. It can help to eat several small ...

  1. Success, Failure, and Aggression.

    ERIC Educational Resources Information Center

    Harris, Mary B.; Fisher, Judith L.

    In order to discover the effects of success and failure on subsequent aggressiveness, 26 male and 55 female college students were randomly assigned to success, failure, and neutral conditions. Those in the success condition were led to feel they were superior to other college students on a task, those in the failure condition were led to feel they…

  2. Ethical Failure and Its Operational Cost

    DTIC Science & Technology

    2011-12-01

    Examples of the First Formulation of the Categorical Imperative ” The Philosophical Quarterly, Vol. 7, No. 26 (Jan., 1957), pp. 50-62 Headquarters...hold as the basis of their service, contributing to cases of Post-Traumatic Stress Disorder (PTSD) and suicide. Moral issues have existed as a part...compromise their values and commit ethical failures for multiple reasons.8 The causes of ethical failure are generally categorized into two theories

  3. Heart failure - fluids and diuretics

    MedlinePlus

    ... Heart failure - discharge Heart failure - home monitoring Heart failure - what to ask ... Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, ...

  4. External coating failures in Venezuelan pipelines

    SciTech Connect

    Rodriguez, V.; Paiva, A.; Castaneda, L.

    1994-12-31

    External organic coatings have been used in Venezuelan pipelines to prevent corrosion in different environments. These environments can be considered critical due to the high temperature of the fluid transported or due to the aggressiveness of the surrounding soils and waters. It has also been found that inadequate application of the coating has contributed greatly to a premature failure. An overview of the techniques used to determine the causes of the failures and the interpretation of the failure analysis will be presented in detail in this paper.

  5. Environmental Impact of Munition and Propellant Disposal (Impact Environnemental de l’Elimination des Munitions et des Combustibles)

    DTIC Science & Technology

    2010-02-01

    AVT-115 Environmental Impact of Munition and Propellant Disposal (Impact environnemental de l’élimination des munitions et des combustibles...TR-AVT-115 Environmental Impact of Munition and Propellant Disposal (Impact environnemental de l’élimination des munitions et des combustibles...meet present and future needs in NATO. RTO-TR-AVT-115 ES - 3 Impact environnemental de l’élimination des munitions et des combustibles

  6. Transport quantique dans des nanostructures

    NASA Astrophysics Data System (ADS)

    Naud, C.

    2002-09-01

    structure des oscillations de conductance en fonction du flux du champ magnétique de période h/e dont l'amplitude est beaucoup plus importante que celle mesurée sur un réseau carré de même dimension. Cette différence constitue une signature d'un effet de localisation induit par le champ magnétique sur la topologie mathcal{T}3. Pour des valeurs spécifiques du champ magnétique, du fait des interférences destructives Aharonov-Bohm, la propagation des fonctions d'ondes est limitée à un ensemble fini de cellule du réseau appelé cage. De la dépendance en température des oscillations de période h/e mesurées sur le réseau mathcal{T}3 nous avons tiré une longueur caractéristique qui peut être rattachée au périmètre des cages. Un phénomène inattendu fut l'observation, pour des champs magnétiques plus importants, d'un doublement de fréquence des oscillations. Ces oscillations de période h/2e pouvant avoir une amplitude supérieure aux oscillations de période h/e, une interprétation en terme d'harmonique n'est pas possible. Enfin, l'influence de la largeur électrique des fils constituant le réseau et donc celle du nombre de canaux par brin a été étudiée en réalisant des grilles électrostatique. Les variations de l'amplitude des signaux en h/e et h/2e en fonction de la tension de grille ont été mesurés.

  7. The failure of earthquake failure models

    USGS Publications Warehouse

    Gomberg, J.

    2001-01-01

    In this study I show that simple heuristic models and numerical calculations suggest that an entire class of commonly invoked models of earthquake failure processes cannot explain triggering of seismicity by transient or "dynamic" stress changes, such as stress changes associated with passing seismic waves. The models of this class have the common feature that the physical property characterizing failure increases at an accelerating rate when a fault is loaded (stressed) at a constant rate. Examples include models that invoke rate state friction or subcritical crack growth, in which the properties characterizing failure are slip or crack length, respectively. Failure occurs when the rate at which these grow accelerates to values exceeding some critical threshold. These accelerating failure models do not predict the finite durations of dynamically triggered earthquake sequences (e.g., at aftershock or remote distances). Some of the failure models belonging to this class have been used to explain static stress triggering of aftershocks. This may imply that the physical processes underlying dynamic triggering differs or that currently applied models of static triggering require modification. If the former is the case, we might appeal to physical mechanisms relying on oscillatory deformations such as compaction of saturated fault gouge leading to pore pressure increase, or cyclic fatigue. However, if dynamic and static triggering mechanisms differ, one still needs to ask why static triggering models that neglect these dynamic mechanisms appear to explain many observations. If the static and dynamic triggering mechanisms are the same, perhaps assumptions about accelerating failure and/or that triggering advances the failure times of a population of inevitable earthquakes are incorrect.

  8. Failure During Sheared Edge Stretching

    NASA Astrophysics Data System (ADS)

    Levy, B. S.; van Tyne, C. J.

    2008-12-01

    Failure during sheared edge stretching of sheet steels is a serious concern, especially in advanced high-strength steel (AHSS) grades. The shearing process produces a shear face and a zone of deformation behind the shear face, which is the shear-affected zone (SAZ). A failure during sheared edge stretching depends on prior deformation in the sheet, the shearing process, and the subsequent strain path in the SAZ during stretching. Data from laboratory hole expansion tests and hole extrusion tests for multiple lots of fourteen grades of steel were analyzed. The forming limit curve (FLC), regression equations, measurement uncertainty calculations, and difference calculations were used in the analyses. From these analyses, an assessment of the primary factors that contribute to the fracture during sheared edge stretching was made. It was found that the forming limit strain with consideration of strain path in the SAZ is a major factor that contributes to the failure of a sheared edge during stretching. Although metallurgical factors are important, they appear to play a somewhat lesser role.

  9. Impact de la preparation des anodes crues et des conditions de cuisson sur la fissuration dans des anodes denses

    NASA Astrophysics Data System (ADS)

    Amrani, Salah

    La fabrication de l'aluminium est realisee dans une cellule d'electrolyse, et cette operation utilise des anodes en carbone. L'evaluation de la qualite de ces anodes reste indispensable avant leur utilisation. La presence des fissures dans les anodes provoque une perturbation du procede l'electrolyse et une diminution de sa performance. Ce projet a ete entrepris pour determiner l'impact des differents parametres de procedes de fabrication des anodes sur la fissuration des anodes denses. Ces parametres incluent ceux de la fabrication des anodes crues, des proprietes des matieres premieres et de la cuisson. Une recherche bibliographique a ete effectuee sur tous les aspects de la fissuration des anodes en carbone pour compiler les travaux anterieurs. Une methodologie detaillee a ete mise au point pour faciliter le deroulement des travaux et atteindre les objectifs vises. La majorite de ce document est reservee pour la discussion des resultats obtenus au laboratoire de l'UQAC et au niveau industriel. Concernant les etudes realisees a l'UQAC, une partie des travaux experimentaux est reservee a la recherche des differents mecanismes de fissuration dans les anodes denses utilisees dans l'industrie d'aluminium. L'approche etait d'abord basee sur la caracterisation qualitative du mecanisme de la fissuration en surface et en profondeur. Puis, une caracterisation quantitative a ete realisee pour la determination de la distribution de la largeur de la fissure sur toute sa longueur, ainsi que le pourcentage de sa surface par rapport a la surface totale de l'echantillon. Cette etude a ete realisee par le biais de la technique d'analyse d'image utilisee pour caracteriser la fissuration d'un echantillon d'anode cuite. L'analyse surfacique et en profondeur de cet echantillon a permis de voir clairement la formation des fissures sur une grande partie de la surface analysee. L'autre partie des travaux est basee sur la caracterisation des defauts dans des echantillons d'anodes crues

  10. Using XML to encode TMA DES metadata

    PubMed Central

    Lyttleton, Oliver; Wright, Alexander; Treanor, Darren; Lewis, Paul

    2011-01-01

    Background: The Tissue Microarray Data Exchange Specification (TMA DES) is an XML specification for encoding TMA experiment data. While TMA DES data is encoded in XML, the files that describe its syntax, structure, and semantics are not. The DTD format is used to describe the syntax and structure of TMA DES, and the ISO 11179 format is used to define the semantics of TMA DES. However, XML Schema can be used in place of DTDs, and another XML encoded format, RDF, can be used in place of ISO 11179. Encoding all TMA DES data and metadata in XML would simplify the development and usage of programs which validate and parse TMA DES data. XML Schema has advantages over DTDs such as support for data types, and a more powerful means of specifying constraints on data values. An advantage of RDF encoded in XML over ISO 11179 is that XML defines rules for encoding data, whereas ISO 11179 does not. Materials and Methods: We created an XML Schema version of the TMA DES DTD. We wrote a program that converted ISO 11179 definitions to RDF encoded in XML, and used it to convert the TMA DES ISO 11179 definitions to RDF. Results: We validated a sample TMA DES XML file that was supplied with the publication that originally specified TMA DES using our XML Schema. We successfully validated the RDF produced by our ISO 11179 converter with the W3C RDF validation service. Conclusions: All TMA DES data could be encoded using XML, which simplifies its processing. XML Schema allows datatypes and valid value ranges to be specified for CDEs, which enables a wider range of error checking to be performed using XML Schemas than could be performed using DTDs. PMID:21969921

  11. Using XML to encode TMA DES metadata.

    PubMed

    Lyttleton, Oliver; Wright, Alexander; Treanor, Darren; Lewis, Paul

    2011-01-01

    The Tissue Microarray Data Exchange Specification (TMA DES) is an XML specification for encoding TMA experiment data. While TMA DES data is encoded in XML, the files that describe its syntax, structure, and semantics are not. The DTD format is used to describe the syntax and structure of TMA DES, and the ISO 11179 format is used to define the semantics of TMA DES. However, XML Schema can be used in place of DTDs, and another XML encoded format, RDF, can be used in place of ISO 11179. Encoding all TMA DES data and metadata in XML would simplify the development and usage of programs which validate and parse TMA DES data. XML Schema has advantages over DTDs such as support for data types, and a more powerful means of specifying constraints on data values. An advantage of RDF encoded in XML over ISO 11179 is that XML defines rules for encoding data, whereas ISO 11179 does not. We created an XML Schema version of the TMA DES DTD. We wrote a program that converted ISO 11179 definitions to RDF encoded in XML, and used it to convert the TMA DES ISO 11179 definitions to RDF. We validated a sample TMA DES XML file that was supplied with the publication that originally specified TMA DES using our XML Schema. We successfully validated the RDF produced by our ISO 11179 converter with the W3C RDF validation service. All TMA DES data could be encoded using XML, which simplifies its processing. XML Schema allows datatypes and valid value ranges to be specified for CDEs, which enables a wider range of error checking to be performed using XML Schemas than could be performed using DTDs.

  12. Diuretics as pathogenetic treatment for heart failure

    PubMed Central

    Guglin, Maya

    2011-01-01

    Increased intracardiac filling pressure or congestion causes symptoms and leads to hospital admissions in patients with heart failure, regardless of their systolic function. A history of hospital admission, in turn, predicts further hospitalizations and morbidity, and a higher number of hospitalizations determine higher mortality. Congestion is therefore the driving force of the natural history of heart failure. Congestion is the syndrome shared by heart failure with preserved and reduced systolic function. These two conditions have almost identical morbidity, mortality, and survival because the outcomes are driven by congestion. A small difference in favor of heart failure with preserved systolic function comes from decreased ejection fraction and left ventricular remodeling which is only present in heart failure with decreased systolic function. The magnitude of this difference reflects the contribution of decreased systolic function and ventricular remodeling to the progression of heart failure. The only treatment available for congestion is fluid removal via diuretics, ultrafiltration, or dialysis. It is the only treatment that works equally well for heart failure with reduced and preserved systolic function because it affects congestion, the main pathogenetic feature of the disease. Diuretics are pathogenetic therapy for heart failure. PMID:21403798

  13. Atrial natriuretic factor binding sites in experimental congestive heart failure

    SciTech Connect

    Bianchi, C.; Thibault, G.; Wrobel-Konrad, E.; De Lean, A.; Genest, J.; Cantin, M. )

    1989-10-01

    A quantitative in vitro autoradiographic study was performed on the aorta, renal glomeruli, and adrenal cortex of cardiomyopathic hamsters in various stages of heart failure and correlated, in some instances, with in vivo autoradiography. The results indicate virtually no correlation between the degree of congestive heart failure and the density of 125I-labeled atrial natriuretic factor ((Ser99, Tyr126)ANF) binding sites (Bmax) in the tissues examined. Whereas the Bmax was increased in the thoracic aorta in moderate and severe heart failure, there were no significant changes in the zona glomerulosa. The renal glomeruli Bmax was lower in mild and moderate heart failure compared with control and severe heart failure. The proportion of ANF B- and C-receptors was also evaluated in sections of the aorta, adrenal, and kidney of control and cardiomyopathic hamsters with severe heart failure. (Arg102, Cys121)ANF (des-(Gln113, Ser114, Gly115, Leu116, Gly117) NH2) (C-ANF) at 10(-6) M displaced approximately 505 of (Ser99, Tyr126)125I-ANF bound in the aorta and renal glomeruli and approximately 20% in the adrenal zona glomerulosa in both series of animals. These results suggest that ANF may exert a buffering effect on the vasoconstriction of heart failure and to a certain extent may inhibit aldosterone secretion. The impairment of renal sodium excretion does not appear to be related to glomerular ANF binding sites at any stage of the disease.

  14. Kidney Failure: What to Expect

    MedlinePlus

    ... Kidneys & How They Work Kidney Disease A-Z Kidney Failure What is kidney failure and how is it treated? Kidney failure ... Methods for Kidney Failure: Peritoneal Dialysis . Peritoneal dialysis Kidney Transplant A kidney transplant places a healthy kidney ...

  15. Deficiencies in the uterine environment and failure to support embryo development

    USDA-ARS?s Scientific Manuscript database

    Pregnancy failure in livestock can result from failure to fertilize the oocyte or embryonic loss during gestation. Although fertilization failure occurs, embryonic mortality has a greater contribution to pregnancy failure. The focus of this review is on cattle and factors affecting, and mechanisms r...

  16. Identification of classical anaphylatoxin as the des-Arg form of the C5a molecule: Evidence of a modulator role for the oligosaccharide unit in human des-Arg74-C5a

    PubMed Central

    Gerard, Craig; Hugli, Tony E.

    1981-01-01

    A functionally active and potentially lethal fragment of the fifth component of complement (C5) is generated during complement activation in serum from animals of various species. This factor, termed the “classical” anaphylatoxin, was isolated from porcine serum and was identified chemically as the des-Arg derivative of the well-characterized C5a molecule. Unlike the C3a and C4a anaphylatoxins, porcine C5a does not require the COOH-terminal arginyl residue for spasmogenic activity. Further degradation of porcine des-Arg74-C5a by carboxypeptidase Y removed glycine-73 and leucine-72 and decreased the intrinsic spasmogenic activity by >90%. Hence, we conclude that, although the arginyl residue is not essential, the COOH-terminal sequence Leu-Gly-Arg contributes structural information that accounts for >90% of C5a activity. Human des-Arg74-C5a, like its porcine counterpart, has instrinsic anaphylatoxin activity; however, higher concentrations were needed to contract the guinea pig ileal tissue (i.e., 1 μM for human des-Arg74-C5a versus 1 nM for porcine des-Arg74-C5a). Furthermore, the des-Arg form of human C5a was only 0.1% as active as porcine des-Arg74-C5a for enhancing vascular permeability in guinea pig skin. In addition to these biological differences, numerous chemical differences exist between the human and porcine des-Arg74-C5a molecules, the most prominent feature being an oligosaccharide entity associated uniquely with the human C5a. When the oligosaccharide unit of human des-Arg74-C5a was removed by glycosidases, leaving a single glucosamine residue attached to the side chain of asparagine-64, activity was enhanced. The human des-Arg74-C5a molecule devoid of the complex oligosaccharide unit exhibited 10-fold stronger spasmogenic activity and 20- to 50-fold greater permeability-enhancing activity than did human des-Arg74-C5a containing the oligosaccharide. Consequently, the oligosaccharide associated with human C5a modulates or suppresses potentially

  17. Duralumin - Defects and Failures

    NASA Technical Reports Server (NTRS)

    Nelson, WM

    1927-01-01

    It is proposed in this paper to identify some of the defects and failures in duralumin most frequently encountered by the aircraft industry with a view to indicate their importance. The defects and failures in duralumin may be classified into the following groups: 1) defects produced during manufacture; 2) defects produced during fabrication; 3) corrosion and erosion; and 4) fatigue failures. Only the first two will be covered in this report.

  18. Early complications. Respiratory failure.

    PubMed

    Zwischenberger, J B; Alpard, S K; Bidani, A

    1999-08-01

    Pulmonary complications following thoracic surgery are common and associated with significant morbidity and mortality. Respiratory failure after pneumonectomy occurs in approximately 5% to 15% of cases and significantly increases patient mortality. Strategies for ventilator support are based on the nature of the underlying complication and the pathophysiology of respiratory failure. This article describes the cause and pathophysiology of respiratory failure and pulmonary embolus postpneumonectomy. Diagnosis, management, and innovative therapies are also reviewed.

  19. La structure des verres étudiée par diffraction des neutrons

    NASA Astrophysics Data System (ADS)

    Cormier, L.

    2003-09-01

    La diffraction des neutrons est une méthode largement utilisée pour déterminer la structure des matériaux amorphes et en particulier des verres. L'utilisation de la méthode de substitution isotopique permet d'extraire les fonctions de distribution de paires partielles centrées autour d'un élément choisi. Nous présentons quelques exemples récents d'études par diffraction des neutrons sur des verres qui ont permis de mieux comprendre à la fois le réseau polymérique de la matrice vitreuse et l'environnement local et à moyenne distance autour des cations. Ces études ont révélées un ordre structural s'étendant au delà des premiers voisins, jusque vers de distances d'environ 10Å. Le couplage avec d'autres méthodes expérimentales (diffraction anormale des rayons X) et des techniques de simulations (dynamique moléculaire, Monte Carlo Inverse ou RMC) sont indispensables pour affiner nos connaissances de la structure des verres.

  20. Micronutrients in chronic heart failure.

    PubMed

    Krim, Selim R; Campbell, Patrick; Lavie, Carl J; Ventura, Hector

    2013-03-01

    Heart failure (HF)-associated mortality remains high, despite guideline-recommended medical therapies. Poor nutritional status and unintentional cachexia have been shown to have a strong association with worse survival in HF patients. Importantly, micronutrient deficiencies are potential contributing factors to the progression of HF. This review aims to summarize contemporary evidence on the role of micronutrients in the pathophysiology and outcome of HF patients. Emphasis will be given to the most well-studied micronutrients, specifically, vitamin D, vitamin B complex, coenzyme Q10 and L-carnitine.

  1. Prendre le virage des partenariats.

    PubMed

    Sebestyen, Norma; Sulatycky, Ron; Rondos, Spyro; Davis, Sheila

    2015-11-01

    Deux projets démontrent que la mise en œuvre de données colligées sur le terrain peut contribuer à régler des problèmes dans le milieu de la santé pour favoriser de meilleurs résultats et de plus grandes efficiences. Dans le premier exemple, une vaste coalition de partenaires publics et privés de l'Alberta recourt aux techniques de mesures améliorées et à la méthodologie du Triple objectif pour améliorer les résultats cliniques de populations de cas complexes et lourds du quartier Eastwood d'Edmonton. On espère que les conclusions novatrices qui en sont tirées seront adaptées à d'autres régions de la province. Dans le deuxième exemple, la Childhood Obesity Foundation s'associe à Merck au Canada et à Ayogo (une société de thérapies numériques située à Vancouver) et utilise le concept novateur de la « ludification » pour mobiliser les jeunes de plus en plus sédentaires du Canada et modifier leurs comportements. © 2015 Collège canadien des leaders en santé

  2. VR-CoDES and patient-centeredness. The intersection points between a measure and a concept.

    PubMed

    Del Piccolo, Lidia

    2017-11-01

    The Verona Coding Definitions of Emotional sequences (VR-CoDES) system has been applied in a wide range of studies, in some of these, because of its attention on healthcare provider's ability to respond to patient emotions, it has been used as a proxy of patient-centeredness. The paper aims to discuss how the VR-CoDES can contribute to the broader concept of patient-centeredness and its limitations. VR-CoDES and patient-centeredness concept are briefly described, trying to detect commonalities and distinctions. The VR-CoDES dimensions of Explicit/non explicit responding and Providing or Reducing Space are analysed in relation to relevant aspects of patient-centred communication. Emotional aspects are encompassed within patient-centeredness model, but they represent only one of the numerous dimensions that contribute to define patient-centeredness as well as Explicit/non explicit responding and Providing or Reducing Space serve different functions during communication. The VR-CoDES can contribute to operationalize the description of emotional aspects emerging in a consultation, by inducing coders to adopt a factual attitude in assessing how health providers react to patient's expression of emotions. To better define empirically which measure affective aspects and dimensions of health provider responses are relevant and may contribute to patient-centeredness in different clinical settings. Copyright © 2017. Published by Elsevier B.V.

  3. Morphometric analysis of renal cortex changes induced by diethylstilbestrol (DES) in Syrian hamsters.

    PubMed

    Chang, C J; Lin, Y C; Brueggemeier, R W; Rikihisa, Y

    1992-12-01

    Estrogen-induced renal adenocarcinoma usually can be readily detected in castrated hamsters after 9 to 12 months of DES treatment. In the present study, we examined the morphological characteristics of the renal cortices of castrated hamsters that had received 3 months of DES treatment in order to describe early histological evidence of carcinogenesis induction. Twelve Syrian Golden hamsters, 8 to 9 weeks of age, were first castrated and then subjected to either subpannicular implantation of a 20 mg DES pellet (experiment group), or sham operation (controls). Morphological and 2-D morphometric evaluations were conducted sequentially on kidney histological sections. Numbers (N's) or area fractions (AF's) of renal components in the juxta-medullary junction of each kidney section were processed for morphometric evaluation. The DES treatment caused a 15% increase in kidney weight, but not body weight. Dysplastic foci associated with hyperplastic tubules were present in 67% of the left kidneys or 17% of the right kidneys of hamsters in the test group, but were absent in kidneys of controls. DES treatment decreased glomeruli N by 33% and increased the vasculature AF by 169% per examination field. DES also increased AF's of glomeruli, proximal tubules, distal tubules, and vasculature by 17, 81, 53 and 346% per nephron, respectively. Our results showed that, after the first three months of DES-treatment, hamster kidneys developed dysplastic foci and their masses were greater than controls. Increased renal components in the juxta-medullary junction region included glomeruli, tubules, and vasculature. The dysplastic foci may be sites of subsequent malignancies, whereas the increased renal mass might be a result of functional adaptation/expression to exogenous estrogen which might contribute to the carcinogenic process.

  4. Etude des effets du martelage repetitif sur les contraintes residuelles

    NASA Astrophysics Data System (ADS)

    Hacini, Lyes

    L'assemblage par soudage peut engendrer des contraintes residuelles. Ces contraintes provoquent des fissurations prematurees et un raccourcissement de la duree de vie des composants. Dans ce contexte, le martelage robotise est utilise pour relaxer ces contraintes residuelles. Trois volets sont presentes: le premier est l'evaluation des effets des impacts unitaires repetes sur le champ de contraintes developpe dans des plaques d'acier inoxydable austenitique 304L vierges ou contenant des contraintes residuelles initiales. Dans la deuxieme partie de ce projet, le martelage est applique grace au robot SCOMPI. Les contraintes residuelles induites et relaxees par martelage sont ensuite mesurees par la methode des contours, qui a ete adaptee a cet effet. Dans la troisieme partie, le martelage est modelise par la methode des elements finis. Un modele axisymetrique developpe grace au logiciel ANSYS permet de simuler des impacts repetes d'un marteau elastique sur une plaque ayant un comportement elastoplastique.

  5. Sleep apnea in chronic heart failure.

    PubMed

    Anselm, Anjali H; Gauthier, Nadine; Beanlands, Rob S B; Haddad, Haissam

    2008-03-01

    As heart failure continues to carry significant morbidity and mortality it is crucial to pursue new lines of therapy. Addressing sleep apnea, which is highly prevalent in these patients, offers just such an avenue. We discuss how sleep apnea may contribute to the propagation of heart failure, and how understanding its effects and reversing these effects might benefit heart failure patients. Continuous positive airway pressure ventilation, atrial pacing, and chronic resynchronization therapy have all been studied in sleep apnea. Some of these therapies have shown benefits in heart failure. This offers hope for improved outcomes, particularly with respect to mortality. Delineating how these therapies affect the heart's energetics and metabolism may also provide further understanding of the relationship between sleep apnea and heart failure. As both obstructive and central sleep apnea are highly prevalent in heart failure, treating these patients with continuous positive airway pressure, atrial pacing, or chronic resynchronization therapy may offer morbidity and mortality benefits. Much remains to be understood about the relationship between sleep apnea and heart failure, and understanding the interaction between the two at both the myocardial and clinical level is crucial.

  6. Retrieval Failure Contributes to Gist-Based False Recognition

    ERIC Educational Resources Information Center

    Guerin, Scott A.; Robbins, Clifford A.; Gilmore, Adrian W.; Schacter, Daniel L.

    2012-01-01

    People often falsely recognize items that are similar to previously encountered items. This robust memory error is referred to as "gist-based false recognition". A widely held view is that this error occurs because the details fade rapidly from our memory. Contrary to this view, an initial experiment revealed that, following the same encoding…

  7. Retrieval Failure Contributes to Gist-Based False Recognition

    ERIC Educational Resources Information Center

    Guerin, Scott A.; Robbins, Clifford A.; Gilmore, Adrian W.; Schacter, Daniel L.

    2012-01-01

    People often falsely recognize items that are similar to previously encountered items. This robust memory error is referred to as "gist-based false recognition". A widely held view is that this error occurs because the details fade rapidly from our memory. Contrary to this view, an initial experiment revealed that, following the same encoding…

  8. Ampoule Failure System

    NASA Technical Reports Server (NTRS)

    Watring, Dale A. (Inventor); Johnson, Martin L. (Inventor)

    1996-01-01

    An ampoule failure system for use in material processing furnaces comprising a containment cartridge and an ampoule failure sensor. The containment cartridge contains an ampoule of toxic material therein and is positioned within a furnace for processing. An ampoule failure probe is positioned in the containment cartridge adjacent the ampoule for detecting a potential harmful release of toxic material therefrom during processing. The failure probe is spaced a predetermined distance from the ampoule and is chemically chosen so as to undergo a timely chemical reaction with the toxic material upon the harmful release thereof. The ampoule failure system further comprises a data acquisition system which is positioned externally of the furnace and is electrically connected to the ampoule failure probe so as to form a communicating electrical circuit. The data acquisition system includes an automatic shutdown device for shutting down the furnace upon the harmful release of toxic material. It also includes a resistance measuring device for measuring the resistance of the failure probe during processing. The chemical reaction causes a step increase in resistance of the failure probe whereupon the automatic shutdown device will responsively shut down the furnace.

  9. Physicists and failure

    NASA Astrophysics Data System (ADS)

    Raheem, Ruby; zilch, Mortimer

    2015-08-01

    In reply to a post on the physicsworld.com blog about the central role of failure in physics (“Success, failure and women in physics”, 10 June, http://ow.ly/O8kvR; see also “Failing better,” Editorial, July p15).

  10. Living with Respiratory Failure

    MedlinePlus

    ... smoking. Emotional Issues and Support Living with respiratory failure may cause fear, anxiety, depression, and stress. Talk about how you feel with your health care team. Talking to a professional counselor also can ... to living with respiratory failure. You can see how other people who have ...

  11. Generalized energy failure criterion.

    PubMed

    Qu, R T; Zhang, Z J; Zhang, P; Liu, Z Q; Zhang, Z F

    2016-03-21

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the "generalized energy criterion", as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components.

  12. Acute Decompensated Heart Failure

    PubMed Central

    Joseph, Susan M.; Cedars, Ari M.; Ewald, Gregory A.; Geltman, Edward M.; Mann, Douglas L.

    2009-01-01

    Hospitalizations for acute decompensated heart failure are increasing in the United States. Moreover, the prevalence of heart failure is increasing consequent to an increased number of older individuals, as well as to improvement in therapies for coronary artery disease and sudden cardiac death that have enabled patients to live longer with cardiovascular disease. The main treatment goals in the hospitalized patient with heart failure are to restore euvolemia and to minimize adverse events. Common in-hospital treatments include intravenous diuretics, vasodilators, and inotropic agents. Novel pharmaceutical agents have shown promise in the treatment of acute decompensated heart failure and may simplify the treatment and reduce the morbidity associated with the disease. This review summarizes the contemporary management of patients with acute decompensated heart failure. PMID:20069075

  13. Failure mechanisms in MEMS.

    SciTech Connect

    Walraven, Jeremy Allen

    2003-07-01

    MEMS components by their very nature have different and unique failure mechanisms than their macroscopic counterparts. This paper discusses failure mechanisms observed in various MEMS components and technologies. MEMS devices fabricated using bulk and surface micromachining process technologies are emphasized. MEMS devices offer uniqueness in their application, fabrication, and functionality. Their uniqueness creates various failure mechanisms not typically found in their bulk or IC counterparts. In ICs, electrical precautions are taken to mitigate failure. In MEMS, both electrical and mechanical precautions must be enacted to reduce the risk of failure and increased reliability. Unlike ICs, many MEMS components are designed to interact with their environment, making the fabrication, testing, and packaging processes critical for the success of the device.

  14. Generalized energy failure criterion

    PubMed Central

    Qu, R. T.; Zhang, Z. J.; Zhang, P.; Liu, Z. Q.; Zhang, Z. F.

    2016-01-01

    Discovering a generalized criterion that can predict the mechanical failure of various different structural materials is one of ultimate goals for scientists in both material and mechanics communities. Since the first study on the failure criterion of materials by Galileo, about three centuries have passed. Now we eventually find the “generalized energy criterion”, as presented here, which appears to be one universal law for various different kinds of materials. The validity of the energy criterion for quantitatively predicting the failure is experimentally confirmed using a metallic glass. The generalized energy criterion reveals the competition and interaction between shear and cleavage, the two fundamental inherent failure mechanisms, and thus provides new physical insights into the failure prediction of materials and structural components. PMID:26996781

  15. Renouvellement des eaux du fjord du Saguenay

    NASA Astrophysics Data System (ADS)

    Belzile, Melany

    Le fjord du Saguenay, localise dans la region subarctique de l'est du Canada, ala particularite d' etre connecte a un estuaire tres energetique plutot que directement a 1' ocean. L'embouchure du fjord est situee ala rencontre d'un chenal profond et d'un seuil de 20m de profondeur qui limite les echanges d'eau entre le fjord et l'estuaire du Saint-Laurent. Cependant, les grandes amplitudes de maree a son embouchure ont le potentiel d'entrainer des eaux denses du Saint-Laurent a l'interieur du fjord renouvelant ainsi les eaux des differents bassins. Dans le but d' a voir une meilleure comprehension de la dynamique et de la saisonnalite des renouvellements dans le bassin interne, deux mouillages y ont ete deployes pour recolter les premieres donnees de courant, sur toute la colonne d' eau et sur plusieurs mois, ainsi que des observations de temperature et de salinite a differentes profondeurs. L'un de ces mouillages n' a malheureusement pas pu etre analyse en detail dfi a la complexite de ses resultats et au manque de temps. Des profils ont ete recoltes le long de section transversales (transects), couvrant plusieurs saisons et plusieurs annees, ce qui a contribue a une meilleure comprehension de la distribution spatiale des masses d'eau dans le fjord. Les resultats montrent que ladynamique du fjord est plus complexe que ce qui avait ete precedemment presente dans la litterature. Un changement saisonnier abrupte dans la circulation du fjord a ete observe a la rni-fevrier. De plus, des renouvellements non-anticipes juste en-dessous de la thermohalocline (˜ 10 m de profondeur) ont ete observes entre la fin de 1' hiver et le milieu de 1' ete. En fonction des saisons, trois types de renouvellement peuvent etre observes : renouvellements profonds a l'automne et au debut de l'hiver suivis des renouvellements de sous-surface et enfin les renouvellements a des profondeurs intermediaires pendant l'ete. Le changement saisonnier abrupte observe au milieu de l'hiver ainsi que la

  16. Ostéosynthèse des fractures des métacarpiens et des phalanges de la main par mini plaque: à propos de 12 cas

    PubMed Central

    Moncef, Erraji; Abdelhafid, Derfoufi; Abdessamad, Kharraji; Omar, Agoumi; Najib, Abdeljaouad; Abdelkrim, Daoudi; Hicham, Yacoubi

    2016-01-01

    Le traitement des fractures instables des métacarpes et des phalanges reste un objet de controverse. Peu de séries ont été rapportées dans la littérature, rendant leur analyse difficile. Nous rapportons une étude rétrospective comportant 12 patients, opérés par cette technique, ayant eu des fractures déplacées des métacarpes ou des phalanges, sur une période de deux ans. Les résultats globaux ont été bons dans 75% des cas, moyenne dans 16,5% des cas et mauvais dans 8,5% des cas. La stabilité du montage par mini plaques des fractures instables des métacarpiens et des phalanges ont permis une mobilisation précoce des articulations de la main, évitant ainsi la raideur. PMID:27800079

  17. Restauration adaptative des contours par une approche inspiree de la prediction des performances

    NASA Astrophysics Data System (ADS)

    Rousseau, Kami

    effectuee et permet de mieux comprendre la contribution de chaque indicateur. L'efficacite de l'outil developpe est comparable a celle d'autres methodes de detection de contours et en fait un choix interessant pour la detection de contours. Les differences de qualite observees entre notre methode et celle de Canny semble etre dues a l'utilisation, ou non, de post-traitements. Grace au logiciel developpe, il est possible de reutiliser la methodologie; cette derniere a permis d'operationnaliser la methode proposee. La possibilite de reutiliser le filtre, sans reentrainement est interessante. La simplicite du parametrage lors de l'utilisation est aussi un avantage. Ces deux facteurs repondent a un besoin de reduire le temps d'utilisation du logiciel. Mots-cles: detection de signal adaptative, caracterisation des performances, reseaux de neurones, imagerie panchromatique, analyse de contours.

  18. Component criticality in failure cascade processes of network systems.

    PubMed

    Zio, Enrico; Sansavini, Giovanni

    2011-08-01

    In this work, specific indicators are used to characterize the criticality of components in a network system with respect to their contribution to failure cascade processes. A realistic-size network is considered as reference case study. Three different models of cascading failures are analyzed, differing both on the failure load distribution logic and on the cascade triggering event. The criticality indicators are compared to classical measures of topological centrality to identify the one most characteristic of the cascade processes considered.

  19. Heart failure in the diabetic population - pathophysiology, diagnosis and management.

    PubMed

    Kasznicki, Jacek; Drzewoski, Jozef

    2014-06-29

    Evidence from clinical trials repeatedly confirms the association of diabetes with heart failure, independent of hypertension, atherosclerosis, coronary artery disease and valvular heart disease. However, the importance of coexistence of diabetes and heart failure is not universally recognized, despite the fact that it may significantly contribute to morbidity and mortality of the diabetic population. It seems that prevention of heart failure, early diagnosis, and appropriate management could improve the outcome. Unfortunately, the etiology of heart failure in diabetic patients is still to be elucidated. It is multifactorial in nature and several cellular, molecular and metabolic factors are implicated. Additionally, there are still no definite guidelines on either the diagnosis and treatment of heart failure in diabetic patients or on the therapy of diabetes in subjects with heart failure. This review focuses on the pathophysiology, diagnosis, and prevention of heart failure in the diabetic population as well as management of both comorbidities.

  20. Peste des Petits Ruminants Virus.

    PubMed

    Baron, M D; Diallo, A; Lancelot, R; Libeau, G

    2016-01-01

    Peste des petits ruminants virus (PPRV) causes a severe contagious disease of sheep and goats and has spread extensively through the developing world. Because of its disproportionately large impact on the livelihoods of low-income livestock keepers, and the availability of effective vaccines and good diagnostics, the virus is being targeted for global control and eventual eradication. In this review we examine the origin of the virus and its current distribution, and the factors that have led international organizations to conclude that it is eradicable. We also review recent progress in the molecular and cellular biology of the virus and consider areas where further research is required to support the efforts being made by national, regional, and international bodies to tackle this growing threat.

  1. [Heart failure and comorbidities].

    PubMed

    Boully, Clémence; Hanon, Olivier

    2015-03-01

    Heart failure is a frequent disease in the elderly. Its clinical presentation is less typical and the prognosis more severe than in younger subjects because heart failure occurs in patients with multiple comorbidities. A comprehensive geriatric assessment should therefore be performed to detect the vulnerabilities and manage the comorbidities. The main diseases associated with heart failure are dementia, depression, malnutrition, atrial fibrillation, coronary artery disease, orthostatic hypotension, renal failure, anemia and iron deficiency. Comorbidities worsen heart failure and makes its treatment more difficult. The identification and treatment of comorbidities improve the prognosis in terms of mortality but especially in terms of quality of life. Caution with drugs is necessary because of pharmacokinetic or pharmacodynamic changes related to aging and the comorbidities. In this context, clinical and laboratory monitoring should be increased, mostly during an acute event (acute heart failure, infection, dehydration, fall, new therapy…). Therefore, the follow-up of elderly patients with heart failure requires a multidisciplinary approach that involves close cooperation between cardiologists, geriatricians, general practitioners, nurses, and pharmacists.

  2. Greening America's Capitals - Des Moines, IA

    EPA Pesticide Factsheets

    Report from Greening America's Capitals project in Des Moines, IA, to help the city enhance the 6th Avenue Corridor with pedestrian and bike improvements and green infrastructure to manage stormwater.

  3. Applying Systems Analysis to Program Failure in Organizations.

    ERIC Educational Resources Information Center

    Holt, Margaret E.; And Others

    1986-01-01

    Certain systems analysis techniques can be applied to examinations of program failure in continuing education to locate weaknesses in planning and implementing stages. Questions to guide an analysis and various procedures are recommended. Twelve issues that contribute to failures or discontinuations are identified. (Author/MLW)

  4. Liver Failure in Pregnancy.

    PubMed

    Bacak, Stephen J; Thornburg, Loralei L

    2016-01-01

    Acute liver failure is a rare but life-threatening medical emergency in pregnancy whose true incidence remains unknown. Many cases of acute liver failure are caused by pregnancy-related conditions such as acute fatty liver of pregnancy and HELLP syndrome. However, acute deterioration in liver function can also be caused by drug overdose, viral infections, and an exacerbation of underlying chronic liver disease. This article provides an overview of the normal liver changes that occur during pregnancy, and summarizes the most common conditions and general management strategies of liver failure during pregnancy.

  5. Damage mechanics - failure modes

    SciTech Connect

    Krajcinovic, D.; Vujosevic, M.

    1996-12-31

    The present study summarizes the results of the DOE sponsored research program focused on the brittle failure of solids with disordered microstructure. The failure is related to the stochastic processes on the microstructural scale; namely, the nucleation and growth of microcracks. The intrinsic failure modes, such as the percolation, localization and creep rupture, are studied by emphasizing the effect of the micro-structural disorder. A rich spectrum of physical phenomena and new concepts that emerges from this research demonstrates the reasons behind the limitations of traditional, deterministic, and local continuum models.

  6. Fonction diélectrique des milieux inhomogènes

    NASA Astrophysics Data System (ADS)

    Berthier, Serge

    This review article is based on the thesis of Berthier — Laboratoire d'Optique des solides, Université P. et M. Curie— and on various contributions or ulterior works. Its aim is to present a critical and detailed review of the main theories of the optical dielectric function of inhomogeneous media. Together with a mathematical description of the theories, we give a physical interpretation of the results and the practical limits of validity. Each theory is compared to experimental results and other theoretical predictions as well. This study is introduced by theoretical reminders about the electric polarization and considerations about the physical meaning of some fundamental parameters when going from a microscopic to a macroscopic point of view. Cette revue est tirée de la thèse de Berthier préparée au Laboratoire d'Optique des Solides, Université P. et M. Curie, ainsi que des travaux qui lui font suite (thèse en préparation de Driss-Khodja) ou de ceux menés parallèlement (systèmes 2D) par d'autres membres de l'équipe. Son ambition est de présenter une étude approfondie et critique des différentes théories de la fonction diélectrique optique des milieux inhomogènes à trois dimensions. Après une description mathématique détaillée des principales théories, nous donnons une interprétation physique des résultats et les limites concrètes d'utilisation de chacune d'elles. Chaque grande théorie est confrontée à la fois à des résultats expérimentaux et aux prédictions des autres théories. Cette étude est précédée de rappels théoriques sur la polarisation électrique et de considérations sur la signification réelle de certains paramètres lors du passage d'un système microscopique isolé à un système macroscopique aléatoire.

  7. Caracterisation des proprietes acoustiques des materiaux poreux a cellules ouvertes et a matrice rigide ou souple

    NASA Astrophysics Data System (ADS)

    Salissou, Yacoubou

    L'objectif global vise par les travaux de cette these est d'ameliorer la caracterisation des proprietes macroscopiques des materiaux poreux a structure rigide ou souple par des approches inverses et indirectes basees sur des mesures acoustiques faites en tube d'impedance. La precision des approches inverses et indirectes utilisees aujourd'hui est principalement limitee par la qualite des mesures acoustiques obtenues en tube d'impedance. En consequence, cette these se penche sur quatre problemes qui aideront a l'atteinte de l'objectif global precite. Le premier probleme porte sur une caracterisation precise de la porosite ouverte des materiaux poreux. Cette propriete en est une de passage permettant de lier la mesure des proprietes dynamiques acoustiques d'un materiau poreux aux proprietes effectives de sa phase fluide decrite par les modeles semi-phenomenologiques. Le deuxieme probleme traite de l'hypothese de symetrie des materiaux poreux selon leur epaisseur ou un index et un critere sont proposes pour quantifier l'asymetrie d'un materiau. Cette hypothese est souvent source d'imprecision des methodes de caracterisation inverses et indirectes en tube d'impedance. Le critere d'asymetrie propose permet ainsi de s'assurer de l'applicabilite et de la precision de ces methodes pour un materiau donne. Le troisieme probleme vise a mieux comprendre le probleme de transmission sonore en tube d'impedance en presentant pour la premiere fois un developpement exact du probleme par decomposition d'ondes. Ce developpement permet d'etablir clairement les limites des nombreuses methodes existantes basees sur des tubes de transmission a 2, 3 ou 4 microphones. La meilleure comprehension de ce probleme de transmission est importante puisque c'est par ce type de mesures que des methodes permettent d'extraire successivement la matrice de transfert d'un materiau poreux et ses proprietes dynamiques intrinseques comme son impedance caracteristique et son nombre d'onde complexe. Enfin, le

  8. Renal neurohormonal regulation in heart failure decompensation.

    PubMed

    Jönsson, Sofia; Agic, Mediha Becirovic; Narfström, Fredrik; Melville, Jacqueline M; Hultström, Michael

    2014-09-01

    Decompensation in heart failure occurs when the heart fails to balance venous return with cardiac output, leading to fluid congestion and contributing to mortality. Decompensated heart failure can cause acute kidney injury (AKI), which further increases mortality. Heart failure activates signaling systems that are deleterious to kidneys such as renal sympathetic nerve activity (RSNA), renin-angiotensin-aldosterone system, and vasopressin secretion. All three reduce renal blood flow (RBF) and increase tubular sodium reabsorption, which may increase renal oxygen consumption causing AKI through renal tissue hypoxia. Vasopressin contributes to venous congestion through aquaporin-mediated water retention. Additional water retention may be mediated through vasopressin-induced medullary urea transport and hyaluronan but needs further study. In addition, there are several systems that could protect the kidneys and reduce fluid retention such as natriuretic peptides, prostaglandins, and nitric oxide. However, the effect of natriuretic peptides and nitric oxide are blunted in decompensation, partly due to oxidative stress. This review considers how neurohormonal signaling in heart failure drives fluid retention by the kidneys and thus exacerbates decompensation. It further identifies areas where there is limited data, such as signaling systems 20-HETE, purines, endothelin, the role of renal water retention mechanisms for congestion, and renal hypoxia in AKI during heart failure.

  9. Heart failure in children - overview

    MedlinePlus

    Congestive heart failure - children; Cor pulmonale - children; Cardiomyopathy - children; CHF - children; Congenital heart defect - heart failure in children; Cyanotic heart disease - heart failure in children; Birth defect of the heart - heart ...

  10. Triac failure detector

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1983-01-01

    A failure detector is provided for detecting unidirectional failures in triacs, particularly as used in power factor controllers for induction motors. In a first embodiment, the triac voltage waveform is sensed and upon detection of an unbalanced signal, corresponding to failure of the triac in either the positive or negative direction, the triac is turned full on in both directions. In a second embodiment, a pair of pulsed signals are derived, the pulse durations of which are proportional to the phase difference between the load current and voltage for each half cycle, and the triac is turned full on responsive to a difference in pulse duration between the half cycle signals. An unidirectional open circuit detector is adapted to use a signal from either of the first and second embodiment to turn the triac off in response to an open circuit failure in either direction.

  11. Inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  12. Acute Liver Failure

    MedlinePlus

    ... cause acute liver failure include the poisonous wild mushroom Amanita phalloides, which is sometimes mistaken for one ... also can spread infection. Don't eat wild mushrooms. It can be difficult to tell the difference ...

  13. Failure to communicate.

    PubMed

    Fiesta, J

    1998-02-01

    When a medication error is coupled with a communication problem, a patient may experience significant injury. Cases involving communication breakdown, i.e, failure to communicate or listen, are discussed.

  14. Common Cause Failure Modeling

    NASA Technical Reports Server (NTRS)

    Hark, Frank; Britton, Paul; Ring, Robert; Novack, Steven

    2015-01-01

    Space Launch System (SLS) Agenda: Objective; Key Definitions; Calculating Common Cause; Examples; Defense against Common Cause; Impact of varied Common Cause Failure (CCF) and abortability; Response Surface for various CCF Beta; Takeaways.

  15. Heart failure - discharge

    MedlinePlus

    ... Heart failure - overview Heart pacemaker High blood pressure Implantable cardioverter-defibrillator Smoking - tips on how to quit Ventricular assist ... ask your doctor How to read food labels Implantable cardioverter defibrillator - discharge Low-salt diet Mediterranean diet Taking warfarin ( ...

  16. Living with Heart Failure

    MedlinePlus

    ... help you in the future. Follow Your Treatment Plan Treatment can relieve your symptoms and make daily ... or nurse about getting flu and pneumonia vaccines. Plan Ahead If you have heart failure, it's important ...

  17. Maximizing wood Failure

    Treesearch

    Peter Koch

    1965-01-01

    The durability of plywood bonds in exterior exposure is commonly measured indirectly by failing wetted specimens in shear; a high percentage of wood failure is accepted in the industry as evidence that the gluebond will be durable.

  18. Heart failure - tests

    MedlinePlus

    CHF - tests; Congestive heart failure - tests; Cardiomyopathy - tests; HF - tests ... An echocardiogram (echo) is a test that uses sound waves to create a moving picture of the heart. The picture is much more detailed than a plain ...

  19. Acute Liver Failure

    MedlinePlus

    ... drugs and anticonvulsants, can cause acute liver failure. Herbal supplements. Herbal drugs and supplements, including kava, ephedra, skullcap ... over-the-counter medications do you take? What herbal supplements do you take? Do you use illegal drugs? ...

  20. What Causes Respiratory Failure?

    MedlinePlus

    ... Conditions Causing Respiratory Failure Figure A shows the location of the lungs, airways, diaphragm, rib cage, pulmonary arteries, brain, and spinal cord ... STATEMENT FOIA NO FEAR ACT OIG CONTACT US ...

  1. Heart failure overview

    MedlinePlus

    ... The most common causes of heart failure are: Coronary artery disease (CAD), a narrowing of the small blood vessels that ... at the same time. A defibrillator sends an electrical pulse to stop life-threatening abnormal heart rhythms. ...

  2. Advanced Heart Failure

    MedlinePlus

    ... doctors, making good decisions requires teamwork. Through shared decision making, doctors and patients consider both the options and ... care you want to receive. What is shared decision making? When heart failure progresses to an advanced stage, ...

  3. Diffusion des Metaux et Evolution Stellaire

    NASA Astrophysics Data System (ADS)

    Turcotte, Sylvain

    Nous presentons dans cette these des modeles d'evolution stellaire incorporant la diffusion microscopique de maniere consistante. Pour la premiere fois, on a calcule l'evolution d'etoiles en tenant compte en detail de l'impact des variations d'abondances sur leur structure. Nous utilisons des spectres monochromatiques pour chacun des elements les plus abondants dans un melange solaire pour recalculer l'opacite pour les abondances et les conditions locales dans l'interieur d'une etoile au cours de son evolution. Nos modeles montrent que la diffusion atomique des metaux a un effet important sur les opacites dan les etoiles de plus de 1.3Msolar ou l'abondance du fer et des autres elements du pic du fer varient substantiellement. Ces etoiles, sans rotation ou champ magnetique, sont proches des etoiles de type Fm-Am dans lesquelles on observe une legere surabondance d'elements du pic du fer en plus d'une sous-abondance de calcium, sous-abondance que l'on obtient egalement. Nous obtenons cependant des surabondances depassant un facteur 10 pour les etoiles de plus de 1.4Msolar ce qui suggere qu'il existe un ou plusieurs mecanismes limitant la diffusion microscopique. La surabondance du fer en surface cause une augmentation, qui peut atteindre un facteur sept, de l'opacite a la limite de la zone convective. Ceci cause un accroissement de la temperature effective et de la masse de la zone convective comparativement aux modeles n'incluant que la diffusion de l'helium. Il s'agit la du principal effet de la diffusion sur la structure interne de ces etoiles. La diffusions n'a pas d'influence sur l'evolution de coeur stellaire dans les etoiles significativement plus massives quie le Soleil. Nous avons verife que l'utilisation de modeles consistants avec diffusion n'apporte pas d'amelioration sensible aux modeles solaires. Les forces radiatives calculees a partir des spectres d'OPAL pour les elements du pic du fer representent une fraction importante de la gravite. On obtient des

  4. Acute renal failure.

    PubMed

    Bellomo, Rinaldo

    2011-10-01

    Acute renal failure (now acute kidney injury) is a common complication of critical illness affecting between 30 and 60% of critically ill patients. The development of a consensus definition (RIFLE--risk, injury, failure, loss, end-stage system) has allowed standardization of reporting and epidemiological work. Multicenter multinational epidemiological studies indicate that sepsis is now the most common cause of acute renal failure in the intensive care unit (ICU) followed by cardiac surgery-associated acute kidney injury. Unfortunately, our understanding of the pathogenesis of acute renal failure in these settings remains limited. Because of such limited understanding, no reproducibly effective therapies have been developed. In addition the diagnosis of acute renal failure still rests upon the detection of changes in serum creatinine, which only occur if more than 50% of glomerular filtration is lost and are often delayed by more than 24 hours. Such diagnostic delays make the implementation of early therapy nearly impossible. In response to these difficulties, there has been a concerted effort to use proteomics to identify novel early biomarkers of acute renal failure. The identification and study of neutrophil gelatinase- associated lipocalin has been an important step in this field. Another area of active interest and investigation relates to the role of intravenous fluid resuscitation and fluid balance. Data from large observational studies and randomized, controlled trials consistently indicate that a positive fluid balance in patients with acute renal failure represents a major independent risk factor for mortality and provides no protection of renal function. The pendulum is clearly swinging away from a fluid-liberal approach to a fluid-conservative approach in these patients. Finally, there is a growing appreciation that acute renal failure may identify patients who are at increased risk of subsequent chronic renal dysfunction and mortality, opening the way

  5. Genesis Failure Investigation Report

    NASA Technical Reports Server (NTRS)

    Klein, John

    2004-01-01

    The-Genesis mission to collect solar-wind samples and return them to Earth for detailed analysis proceeded successfully for 3.5 years. During reentry on September 8, 2004, a failure in the entry, descent and landing sequence resulted in a crash landing of the Genesis sample return capsule. This document describes the findings of the avionics sub-team that supported the accident investigation of the JPL Failure Review Board.

  6. Heart failure in pregnancy.

    PubMed

    Rutherford, John D

    2012-12-01

    With increasing maternal age and the presence of comorbid conditions such as hypertension, cardiovascular assessment and monitoring is the responsibility of all clinicians caring for pregnant patients. Furthermore, there are specific conditions, such as mitral stenosis, peripartum cardiomyopathy, and preeclampsia, that can be associated with heart failure and secondary maternal (and fetal) mortality and morbidity. The important causes of heart failure in pregnancy are discussed.

  7. Equipment Failure Analysis

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Tennessee Eastman uses NASTRAN to minimize lost production by pinpointing the causes of equipment failures and preventing recurrences. An example of the program's utility involves a large centrifugal fan which developed cracks during start-ups and shutdowns. This information prompted redesign of the fan. Tennessee Eastman has made extensive use of NASTRAN, both as failure analysis tool and as an aid in redesigning production hardware.

  8. Premature ovarian failure.

    PubMed

    Kalantaridou, S N; Davis, S R; Nelson, L M

    1998-12-01

    In 1% of women, premature ovarian failure develops by 40 years of age, a condition causing amenorrhea, infertility, sex steroid deficiency, and elevated gonadotropins. Early loss of ovarian function has significant psychosocial sequelae and major health implications. These young women have a nearly two-fold age-specific increase in mortality rate. Among women with spontaneous premature ovarian failure who have a normal karyotype, half have ovarian follicles remaining in the ovary that function intermittently. Indeed, pregnancies have occurred after the diagnosis of premature ovarian failure. Thus, premature ovarian failure should not be considered as a premature menopause. Young women with this disorder have a 5% to 10% chance for spontaneous pregnancy. Attempts at ovulation induction using various regimens fail to induce ovulation rates greater than those seen in untreated patients; however, oocyte donation for women desiring fertility is an option. Young women with premature ovarian failure need a thorough assessment, sex steroid replacement, and long-term surveillance to monitor therapy. Estrogen-progestin replacement therapy should be instituted as soon as the diagnosis is made. Androgen replacement should also be considered for women with low libido, persistent fatigue, and poor well-being despite taking adequate estrogen replacement. Women with premature ovarian failure should be followed up for the presence of associated autoimmune endocrine disorders such as hypothyroidism, adrenal insufficiency, and diabetes mellitus.

  9. Mechanisms for cachexia in heart failure.

    PubMed

    Pureza, Vincent; Florea, Viorel G

    2013-12-01

    The combination of profound muscle wasting and severe weight loss that occurs in heart failure is a complex phenomenon that involves the interplay of numerous factors. In this article, we describe processes that contribute to cachexia, as part of the clinical sequelae of heart failure, and their potential underlying mechanisms. While multiple mechanisms of cardiac cachexia have been described, we propose a multifactorial etiology for this condition that includes, but is not limited to, nutritional and gastrointestinal alterations, immunological and neurohormonal activation, and anabolic and catabolic imbalance.

  10. Effets perturbateurs endocriniens des pesticides organochlores.

    PubMed

    Charlier, C; Plomteux, G

    2002-01-01

    Xenoestrogens such organochlorine pesticides are known to induce changes in reproductive development, function or behaviour in wildlife. Because these compounds are able to modify the estrogens metabolism, or to compete with estradiol for binding to the estrogen receptor, it may be possible that these products affect the risk of developing impaired fertility, precocious puberty or some kinds of cancer in man. Le plus ancien récit de lutte contre la pollution remonte à une légende indienne racontant que la divinité Sing-bonga était incommodée par les émanations des fours dans lesquels les Asuras fondaient leurs métaux (1). Evidemment depuis, la problématique n-a cessé de s-accroître et la contamination de la Terre par de nombreux polluants est devenue aujourd-hui un problème majeur de notre Société. La protection de notre environnement est une question capitale qui doit être respectée malgré la pression économique actuelle et qui ne cessera de croître au cours des prochaines années même si l-identification objective et indiscutable de ce qui est essentiel - donc devant être prioritairement garanti sur la planète - est difficile à cerner (2). « Un oiseau en mauvais état ne pond pas de bons oeufs » disait un proverbe grec. Mais ce n-est qu-à partir de la seconde moitié du XXème siècle que les toxicologues ont commencé à identifier les effets qu-avaient entraînés à l-échelle mondiale les pollutions émises aux XIXème siècle sur la faune sauvage et sur le cheptel (3). L-histoire contemporaine des pesticides industriels commence vers 1874 (synthèse des organochlorés) et se poursuit tout au long de ces 2 siècles en passant par la synthèse des organophosphorés (1950), des carbamates (1970) et des pyréthroïdes (1975) (4). Le dichlorodiphényltrichloroéthane (DDT) a été synthétisé pour la première fois par un étudiant en cours de préparation de sa thèse de doctorat : Othmer Zeidler. La production, reprise par les

  11. Dialysis Arteriovenous Fistula Failure and Angioplasty: Intimal Hyperplasia and Other Causes of Access Failure.

    PubMed

    Duque, Juan C; Tabbara, Marwan; Martinez, Laisel; Cardona, Jose; Vazquez-Padron, Roberto I; Salman, Loay H

    2017-01-01

    The arteriovenous fistula (AVF) is the preferred hemodialysis access type because it has better patency rates and fewer complications than other access types. However, primary failure remains a common problem impeding AVF maturation and adding to patients' morbidity and mortality. Juxta-anastomotic (or inflow) stenosis is the most common reason leading to primary failure, and percutaneous transluminal angioplasty continues to be the gold-standard treatment with excellent success rates. Intimal hyperplasia (IH) has been traditionally blamed as the main pathophysiologic culprit, but new evidence raises doubts regarding the contribution of IH alone to primary failure. We report a 64-year-old man with a 2-stage brachiobasilic AVF that was complicated by failure 4 months after creation. An angiogram showed multiple juxta-anastomotic and midfistula stenotic lesions. Percutaneous transluminal angioplasty was successful in assisting maturation and subsequently cannulating the AVF for hemodialysis treatment. We failed to identify the underlying cause of stenosis because biopsy specimens from fistula tissue obtained at the time of transposition revealed no occlusive IH. This case emphasizes the need for additional research on factors contributing to AVF failure besides IH and highlights the need for more therapeutic options to reduce AVF failure rate. Copyright © 2016 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  12. Neonatal acute liver failure.

    PubMed

    Taylor, Sarah A; Whitington, Peter F

    2016-05-01

    Neonatal acute liver failure (NALF) is a rare disease about which there is little published data; however, NALF is an extremely important condition as it is distinct from acute liver failure seen in older children and adults. First, unlike acute liver failure in older patients, NALF can be diagnosed in an infant with cirrhosis. This is due to the fetal-neonatal continuum of liver disease, or the principle that neonatal liver failure may be the result of a liver disease that began in utero. Further differences exist in the mechanism of disease, diagnostic principles, and the common etiologies of NALF when compared with pediatric and adult acute liver failure. This review will address many of the distinguishing features of NALF and focus on the most common etiologies of NALF, including gestational alloimmune liver disease (GALD), the most common cause of NALF. Additionally, this review will provide insight into the pathogenesis, diagnosis, and treatment of this rare condition. Liver Transplantation 22 677-685 2016 AASLD. © 2016 American Association for the Study of Liver Diseases.

  13. [Heart failure and anemia].

    PubMed

    Reda, S; Motloch, L J; Hoppe, U C

    2013-09-01

    Chronic heart failure has an age-dependent prevalence of 2% and is therefore one of the most frequent diseases in western societies. A reduced hemoglobin concentration according to the definition of the World Health Organization is a common comorbidity affecting more than half of all heart failure patients. Elderly patients, patients suffering from renal impairment and women are more likely to develop anemia but a definitive etiology of anemia is only identified in the minority of cases. Anemia is associated with a poor clinical status and a greater risk of hospitalization and is a predictive factor for increased mortality. The incidence of anemia appears to increase with a poorer functional class. Intravenous iron therapy improves the exercise capacity in patients with systolic heart failure and iron deficiency and is currently being recommended for patients with persistent symptoms despite optimal medical and device therapy. However, erythropoietin-stimulating agents as a treatment for anemia in chronic heart failure have failed to improve clinical outcome in a large randomized trial. In patients with heart failure but with maintained ejection fraction, anemia is also associated with a poor prognosis. Specific therapeutic recommendations for these patients are still not available.

  14. Heart Failure in South Asia

    PubMed Central

    Sivadasan Pillai, Harikrishnan; Ganapathi, Sanjay

    2013-01-01

    South Asia (SA) is both the most populous and the most densely populated geographical region in the world. The countries in this region are undergoing epidemiological transition and are facing the double burden of infectious and non-communicable diseases. Heart failure (HF) is a major and increasing burden all over the world. In this review, we discuss the epidemiology of HF in SA today and its impact in the health system of the countries in the region. There are no reliable estimates of incidence and prevalence of HF (heart failure) from this region. The prevalence of HF which is predominantly a disease of the elderly is likely to rise in this region due to the growing age of the population. Patients admitted with HF in the SA region are relatively younger than their western counterparts. The etiology of HF in this region is also different from the western world. Untreated congenital heart disease and rheumatic heart disease still contribute significantly to the burden of HF in this region. Due to epidemiological transition, the prevalence of hypertension, diabetes mellitus, obesity and smoking is on the rise in this region. This is likely to escalate the prevalence of HF in South Asia. We also discuss potential developments in the field of HF management likely to occur in the nations in South Asia. Finally, we discuss the interventions for prevention of HF in this region PMID:23597297

  15. Heart failure in South Asia.

    PubMed

    Pillai, Harikrishnan Sivadasan; Ganapathi, Sanjay

    2013-05-01

    South Asia (SA) is both the most populous and the most densely populated geographical region in the world. The countries in this region are undergoing epidemiological transition and are facing the double burden of infectious and non-communicable diseases. Heart failure (HF) is a major and increasing burden all over the world. In this review, we discuss the epidemiology of HF in SA today and its impact in the health system of the countries in the region. There are no reliable estimates of incidence and prevalence of HF (heart failure) from this region. The prevalence of HF which is predominantly a disease of the elderly is likely to rise in this region due to the growing age of the population. Patients admitted with HF in the SA region are relatively younger than their western counterparts. The etiology of HF in this region is also different from the western world. Untreated congenital heart disease and rheumatic heart disease still contribute significantly to the burden of HF in this region. Due to epidemiological transition, the prevalence of hypertension, diabetes mellitus, obesity and smoking is on the rise in this region. This is likely to escalate the prevalence of HF in South Asia. We also discuss potential developments in the field of HF management likely to occur in the nations in South Asia. Finally, we discuss the interventions for prevention of HF in this region.

  16. Mitochondria in cardiac hypertrophy and heart failure

    PubMed Central

    Rosca, Mariana G.; Tandler, Bernard; Hoppel, Charles L.

    2013-01-01

    Heart failure (HF) frequently is the unfavorable outcome of pathological heart hypertrophy. In contrast to physiological cardiac hypertrophy, which occurs in response to exercise and leads to full adaptation of contractility to the increased wall stress, pathological hypertrophy occurs in response to volume or pressure overload, ultimately leading to contractile dysfunction and HF. Because cardiac hypertrophy impairs the relationship between ATP demand and production, mitochondrial bioenergetics must keep up with the cardiac hypertrophic phenotype. We review data regarding the mitochondrial proteomic and energetic remodeling in cardiac hypertrophy, as well as the temporal and causal relationship between mitochondrial failure to match the increased energy demand and progression to cardiac decompensation. We suggest that the maladaptive effect of sustained neuroendocrine signals on mitochondria leads to bioenergetic fading which contributes to the progression from cardiac hypertrophy to failure. PMID:22982369

  17. Isolated ultrafiltration in heart failure patients.

    PubMed

    Costanzo, Maria Rosa; Ronco, Claudio

    2012-06-01

    Most heart failure hospitalizations are due to volume overload, which contributes to disease progression. Heart failure decompensation is typically treated with intravenous diuretics, which are of limited efficacy especially in patients with underlying chronic kidney disease. Since the introduction of hemodialysis, ultrafiltration has been used to remove excess body fluid. Newer, simplified isolated ultrafiltration devices make ultrafiltration feasible at most hospitals and in less acute care settings. Veno-venous ultrafiltration is characterized by transport of solutes and water across a semipermeable membrane in response to a transmembrane pressure gradient generated by a peristaltic pump. Monitoring of ultrafiltration requires a combination of clinical and biomarkers values. Hemodynamic instability due to overaggressive fluid removal must be avoided. Based on recent clinical trials, practice guidelines state that ultrafiltration is reasonable for patients with congestion refractory to medical therapy (Class IIa, Level of Evidence B). Unanswered questions regarding ultrafiltration in heart failure patients include optimal fluid removal rates, effect on long-term survival, and cost.

  18. Heart failure and Alzheimer′s disease

    PubMed Central

    Cermakova, P; Eriksdotter, M; Lund, L H; Winblad, B; Religa, P; Religa, D

    2015-01-01

    It has recently been proposed that heart failure is a risk factor for Alzheimer′s disease. Decreased cerebral blood flow and neurohormonal activation due to heart failure may contribute to the dysfunction of the neurovascular unit and cause an energy crisis in neurons. This leads to the impaired clearance of amyloid beta and hyperphosphorylation of tau protein, resulting in the formation of amyloid beta plaques and neurofibrillary tangles. In this article, we will summarize the current understanding of the relationship between heart failure and Alzheimer′s disease based on epidemiological studies, brain imaging research, pathological findings and the use of animal models. The importance of atherosclerosis, myocardial infarction, atrial fibrillation, blood pressure and valve disease as well as the effect of relevant medications will be discussed. PMID:25041352

  19. Mitochondria in cardiac hypertrophy and heart failure.

    PubMed

    Rosca, Mariana G; Tandler, Bernard; Hoppel, Charles L

    2013-02-01

    Heart failure (HF) frequently is the unfavorable outcome of pathological heart hypertrophy. In contrast to physiological cardiac hypertrophy, which occurs in response to exercise and leads to full adaptation of contractility to the increased wall stress, pathological hypertrophy occurs in response to volume or pressure overload, ultimately leading to contractile dysfunction and HF. Because cardiac hypertrophy impairs the relationship between ATP demand and production, mitochondrial bioenergetics must keep up with the cardiac hypertrophic phenotype. We review data regarding the mitochondrial proteomic and energetic remodeling in cardiac hypertrophy, as well as the temporal and causal relationships between mitochondrial failure to match the increased energy demand and progression to cardiac decompensation. We suggest that the maladaptive effect of sustained neuroendocrine signals on mitochondria leads to bioenergetic fading which contributes to the progression from cardiac hypertrophy to failure. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism". Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Positionsbestimmung des Unternehmens: Interne und externe Analyse

    NASA Astrophysics Data System (ADS)

    Bergmann, Lars; Crespo, Isabel; Portmann, Stefan

    Die Initiierung und Lenkung von Maßnahmen zur integrierten Modernisierung zielen auf die Verbesserung der Wettbewerbsfähigkeit eines Unternehmens ab. Damit diese Maßnahmen zielgerichtet die Wettbewerbsfähigkeit verbessern können, ist Wissen über die bestehende Wettbewerbsfähigkeit sowie über die bestehenden Fähigkeiten eine zentrale Voraussetzung. Eine zielgerichtete Auswahl problemadäquater Maßnahmen zur Verbesserung der Wettbewerbsfähigkeit bedarf daher im Vorfeld einer Bewertung der aktuellen Situation des Unternehmens im Sinne einer Positionsbestimmung. Erst wenn die internen Stärken und Schwächen sowie die externen Chancen und Risiken identifiziert sind, kann ein ganzheitliches Bild von der Position eines Unternehmens in seiner Umwelt gewonnen werden. Auf Basis der Kenntnisse über die Position des Unternehmens können anschließend zielgerichtet Maßnahmen ausgewählt werden, die einen Beitrag zur Verbesserung der Wettbewerbsfähigkeit des Unternehmens haben. Damit kommt der Positionsbestimmung als initialer Schritt des Prozesses der strategischen Unternehmensplanung eine zentrale Bedeutung im Rahmen der integrierten Modernisierung zu. Erfolgt die Auswahl von Maßnahmen ohne eine vorherige Positionsbestimmung, also lediglich auf Basis drängender Probleme, so besteht die Gefahr einer unbedachten und nur auf das "hier und heute“ bezogenen Schwerpunktbildung ohne Berücksichtigung der mittel- und langfristigen Ziele des Unternehmens.

  1. BIOASSAY VESSEL FAILURE ANALYSIS

    SciTech Connect

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  2. Weld failure detection

    DOEpatents

    Pennell, William E.; Sutton, Jr., Harry G.

    1981-01-01

    Method and apparatus for detecting failure in a welded connection, particrly applicable to not readily accessible welds such as those joining components within the reactor vessel of a nuclear reactor system. A preselected tag gas is sealed within a chamber which extends through selected portions of the base metal and weld deposit. In the event of a failure, such as development of a crack extending from the chamber to an outer surface, the tag gas is released. The environment about the welded area is directed to an analyzer which, in the event of presence of the tag gas, evidences the failure. A trigger gas can be included with the tag gas to actuate the analyzer.

  3. Failure to Diagnose Failure to Grow.

    PubMed

    Rose; Strasburger; Penland

    1996-10-01

    A 14-year-old female presented with a 3-week history of sore throat, hoarseness, croupy nonproductive cough, fever, diarrhea, and 5.5-kg weight loss. She was a poor student and "picky eater," and both her current weight and height (18.5 kg and 128 cm) were far below the fifth percentile. Her apparent failure to thrive was a source of concern, and although her diarrhea appeared to be acute, she began to have guaiac-positive stools, and admitted to chronic episodes of diarrhea and recurrent abdominal pains. A colonoscopy revealed chronic aphthous ulcers consistent with Crohn's disease of the large bowel. She was discharged on nutritional supplements, high-dose prednisone therapy, and mesalimine delayed-release tablets.

  4. Lactulose and renal failure.

    PubMed

    Vogt, B; Frey, F J

    1997-01-01

    The introduction of lactulose as a new therapeutic agent for treatment of hepatic encephalopathy was a major breakthrough in this field. It was hypothesized that lactulose might prevent postoperative renal impairment after biliary surgery in patients with obstructive jaundice. The presumable mechanism purported was the diminished endotoxinemia by lactulose. Unfortunately, such a reno-protective effect has not been shown conclusively until now in clinical studies. In chronic renal failure lactulose is known to promote fecal excretion of water, sodium, potassium, amonium, urea, creatinine and protons. Thus, lactulose could be useful for the treatment of chronic renal failure. However, compliance to the therapy represents a major problem.

  5. Hypothyroid acute renal failure.

    PubMed

    Birewar, Sonali; Oppenheimer, Mark; Zawada, Edward T

    2004-03-01

    Muscular disorders and even hypothyroid myopathy with elevated muscle enzymes are commonly seen in hypothyroidism. In this paper, we report a case of acute renal failure in a 35-year old male patient with myalgia. His serum creatinine reached a level of 2.4 mg/dl. Later, his myalgia was found to be due to hypothyroidism with TSH of over 500 uiv/ml. With thyroid replacement therapy, myalgia and his serum creatinine stabilized and subsequently improved. Hypothyroidism, although rare, has been reported as a definite and authentic cause of rhabdomyolysis. As a result, hypothyroidism must be considered in patients presenting with acute renal failure and elevated muscle enzymes.

  6. Diuretics for heart failure.

    PubMed

    Faris, Rajaa F; Flather, Marcus; Purcell, Henry; Poole-Wilson, Philip A; Coats, Andrew J S

    2012-02-15

    Chronic heart failure is a major cause of morbidity and mortality worldwide. Diuretics are regarded as the first-line treatment for patients with congestive heart failure since they provide symptomatic relief. The effects of diuretics on disease progression and survival remain unclear. To assess the harms and benefits of diuretics for chronic heart failure Updated searches were run in the Cochrane Central Register of Controlled Trials in The Cochrane Library (CENTRAL Issue 1 of 4, 2011), MEDLINE (1966 to 22 February 2011), EMBASE (1980 to 2011 Week 07) and HERDIN database (1990 to February 2011). We hand searched pertinent journals and reference lists of papers were inspected. We also contacted manufacturers and researchers in the field. No language restrictions were applied. Double-blinded randomised controlled trials of diuretic therapy comparing one diuretic with placebo, or one diuretic with another active agent (e.g. ACE inhibitors, digoxin) in patients with chronic heart failure. Two authors independently abstracted the data and assessed the eligibility and methodological quality of each trial. Extracted data were analysed by determining the odds ratio for dichotomous data, and difference in means for continuous data, of the treated group compared with controls. The likelihood of heterogeneity of the study population was assessed by the Chi-square test. If there was no evidence of statistical heterogeneity and pooling of results was clinically appropriate, a combined estimate was obtained using the fixed-effects model. This update has not identified any new studies for inclusion. The review includes 14 trials (525 participants), 7 were placebo-controlled, and 7 compared diuretics against other agents such as ACE inhibitors or digoxin. We analysed the data for mortality and for worsening heart failure. Mortality data were available in 3 of the placebo-controlled trials (202 participants). Mortality was lower for participants treated with diuretics than for

  7. Congestive Heart Failure.

    PubMed

    Scott, Michael C; Winters, Michael E

    2015-08-01

    Patients with acute decompensated heart failure are usually critically ill and require immediate treatment. However, most are not volume overloaded. Emergency department (ED) management is based on rapid initiation of noninvasive positive-pressure ventilation and aggressive titration of nitrates. Afterload reduction with an angiotensin-converting enzyme inhibitor can be considered. A diuretic should not be administered before optimal preload and afterload reduction has been achieved. Short-term inotropic therapy can be considered in select patients with cardiogenic shock and acute decompensated heart failure (ADHF) who fail to respond to standard therapy.

  8. Failure detection and identification

    NASA Technical Reports Server (NTRS)

    Massoumnia, Mohammad-Ali; Verghese, George C.; Willsky, Alan S.

    1989-01-01

    Using the geometric concept of an unobservability subspace, a solution is given to the problem of detecting and identifying control system component failures in linear, time-invariant systems. Conditions are developed for the existence of a causal, linear, time-invariant processor that can detect and uniquely identify a component failure, first for the case where components can fail simultaneously, and then for the case where they fail only one at a time. Explicit design algorithms are provided when these conditions are satisfied. In addition to time-domain solvability conditions, frequency-domain interpretations of the results are given, and connections are drawn with results already available in the literature.

  9. Common Cause Failure Modes

    NASA Technical Reports Server (NTRS)

    Wetherholt, Jon; Heimann, Timothy J.; Anderson, Brenda

    2011-01-01

    High technology industries with high failure costs commonly use redundancy as a means to reduce risk. Redundant systems, whether similar or dissimilar, are susceptible to Common Cause Failures (CCF). CCF is not always considered in the design effort and, therefore, can be a major threat to success. There are several aspects to CCF which must be understood to perform an analysis which will find hidden issues that may negate redundancy. This paper will provide definition, types, a list of possible causes and some examples of CCF. Requirements and designs from NASA projects will be used in the paper as examples.

  10. Dynamic DDES On DES Type Grid

    NASA Astrophysics Data System (ADS)

    Yin, Zifei; Durbin, Paul

    2014-11-01

    A dynamic procedure allows a DES formulation that we developed to adjustCDES for different flow configurations. Similarly to the dynamic Smagorinsky model, the grid is required to be fine enough to resolve a significant portion of the inertial range. In some cases, that requirement conflicts with the goal of DES to cut down computing cost. The current effort is therefore to determine a properCDES value by approximately recovering some unresolved small scales from primary, filtered solution. Repeated test filtering is adopted here to compute the approximation of the unfiltered solution. The formulation is based on the dynamicl2 w DDES model and different geometries with varies grid resolution are tested to determine the applicability of proposed formultion on DES type grids.

  11. Cross-Correlating DES and SPT

    NASA Astrophysics Data System (ADS)

    Baxter, Eric

    2017-01-01

    The Dark Energy Survey (DES) and the South Pole Telescope (SPT) provide a uniquely powerful combination of overlapping optical imaging and cosmic microwave background (CMB) data. Cross-correlations between DES and SPT are expected to arise from several physical effects, including gravitational lensing, the Sunyaev-Zel'dovich (SZ) effect, and the Integrated Sachs-Wolfe effect. The resultant correlations contain information not accessible to either experiment on its own. Measurement of these correlations offers several exciting possibilities, such as improved cosmological parameter constraints, improved understanding of systematics affecting the two experiments, and calibration of the masses of galaxy clusters at high redshift. In this talk I will summarize recent results obtained by cross-correlating early DES data with data from the SPT-SZ survey and will discuss prospects for future cross-correlation measurements with these two surveys.

  12. Effet Hall et Magnetisme des Alliages Amorphes Nickel-Zirconium Fabriques Par Pulverisation

    NASA Astrophysics Data System (ADS)

    Morel, Robert

    Cette these se situe dans le cadre d'une etude des proprietes electroniques et structurales des alliages metalliques amorphes, en cours depuis quelques annees a l'Universite de Montreal. Ce programme nous a entre autres amene a caracteriser la magnetoresistivite et l'effet Hall d'alliages FeZr, CoZr et NiZr, ce qui a permis de mettre en evidence deux caracteristiques de l'effet Hall: Dans les alliages amorphes ferromagnetiques, la resistivite elevee engendre un effet Hall extraordinaire beaucoup plus important que celui enregistre dans les metaux cristallins. La polarisation des spins entrai ne une asymetrie de la diffusion qui, tant dans les phases cristalline et amorphe, est tenue responsable de cette contribution. L'autre particularite du comportement de Hall de ces systemes est le renversement de signe du coefficient de Hall ordinaire, qui passe du negatif au positif dans les echantillons plus riches en zirconium. Dans les metaux cristallins, un modele d'electrons libres predit un signe negatif a moins que la conduction ne soit dominee par les trous. Or, dans un milieu desordonne les memes concepts sont difficilement applicables et de nouvelles theories ont du etre elaborees pour expliquer ce phenomene. Jusqu'a maintenant, l'etude des alliages amorphes nickel-zirconium s'est faite surtout a partir d'echantillons fabriques par trempe sur roue. Malheureusement cette technique ne permet pas la fabrication d'alliages contenant plus de 70% de nickel, a l'exception du seul compose Ni _{90}Zr_{10 }. Pour pallier a cette lacune et etendre nos connaissance a l'ensemble de la gamme de compositions, nous avons fabrique par pulverisation cathodique des echantillons NiZr amorphes--et quelques alliages cristallins tres riches en nickel--couvrant une bonne partie de la gamme interdite par la technique de trempe sur roue. Dans un premier temps, par comparaison avec les resultats connus nous avons mis en evidence les similitudes et les differences entre les alliages obtenus par

  13. Heart failure with preserved ejection fraction

    PubMed Central

    ElGuindy, Ahmed; Yacoub, Magdi H

    2012-01-01

    Abstract Heart failure with preserved ejection fraction (HFpEF) has recently emerged as a major cause of cardiovascular morbidity and mortality. Contrary to initial beliefs, HFpEF is now known to be as common as heart failure with reduced ejection fraction (HFrEF) and carries an unacceptably high mortality rate. With a prevalence that has been steadily rising over the past two decades, it is very likely that HFpEF will represent the dominant heart failure phenotype over the coming few years. The scarcity of trials in this semi-discrete form of heart failure and lack of unified enrolment criteria in the studies conducted to date might have contributed to the current absence of specific therapies. Understanding the epidemiological, pathophysiological and molecular differences (and similarities) between these two forms of heart failure is cornerstone to the development of targeted therapies. Carefully designed studies that adhere to unified diagnostic criteria with the recruitment of appropriate controls and adoption of practical end-points are urgently needed to help identify effective treatment strategies. PMID:25610841

  14. Detecting dam failures

    SciTech Connect

    Knarr, C.M.; Barker, T.J.; McKenery, S.F. )

    1994-06-01

    This article describes efforts by Southern California Edison to meet Federal Energy Regulatory Commission requirements for unattended dam monitoring against failure. The topics include a description of the two dam systems, monitoring system design and operation including warning sirens for remote camping areas, and installation of the systems.

  15. Preventing Early Learning Failure.

    ERIC Educational Resources Information Center

    Sornson, Bob, Ed.

    Noting that thousands of young children with the capacity to experience school success do not because they are unprepared for school learning activities, have experienced physical or emotional setbacks that cause them to be at risk for early learning failure, have never experienced limits on their behavior, or have mild sensory or motor deficits,…

  16. Failure in Education

    ERIC Educational Resources Information Center

    Carpenter, Peter

    2009-01-01

    In this article, it is argued that Kurt Hahn felt that it was important for children to experience 'failure' at times and to learn how to cope with it. If this is no longer desirable in the classroom, it ought to be possible to encourage children to be adventurous and "take risks" in a wide range of Outward Bound activities.

  17. Learning from Failures.

    ERIC Educational Resources Information Center

    Saffran, Murray

    1991-01-01

    Describes mistakes made in trying to change the Nutrition and Digestion section of a medical biochemistry course. Author tried to make the section student taught and reports nine mistakes including the following: ignoring active opposition of colleagues, failure to assess the receptivity of the class to a new form of teaching, and overestimating…

  18. Learning from Failures.

    ERIC Educational Resources Information Center

    Saffran, Murray

    1991-01-01

    Describes mistakes made in trying to change the Nutrition and Digestion section of a medical biochemistry course. Author tried to make the section student taught and reports nine mistakes including the following: ignoring active opposition of colleagues, failure to assess the receptivity of the class to a new form of teaching, and overestimating…

  19. Kidney (Renal) Failure

    MedlinePlus

    ... the ureter (s) or a tube connected to an external drainage bag. Both options are used to unblock the ureters in order to allow proper urine flow from the kidneys if this has been identified as the cause for the renal failure. Surgical treatment such as a urinary stent or ...

  20. Preventing Early Learning Failure.

    ERIC Educational Resources Information Center

    Sornson, Bob, Ed.

    Noting that thousands of young children with the capacity to experience school success do not because they are unprepared for school learning activities, have experienced physical or emotional setbacks that cause them to be at risk for early learning failure, have never experienced limits on their behavior, or have mild sensory or motor deficits,…

  1. Designing for Productive Failure

    ERIC Educational Resources Information Center

    Kapur, Manu; Bielaczyc, Katerine

    2012-01-01

    In this article, we describe the design principles undergirding "productive failure" (PF; M. Kapur, 2008). We then report findings from an ongoing program of research on PF in mathematical problem solving in 3 Singapore public schools with significantly different mathematical ability profiles, ranging from average to lower ability. In…

  2. PREVENTION OF FAILURE.

    ERIC Educational Resources Information Center

    National Education Association, Washington, DC.

    THE IMPORTANCE OF THE PREVENTION OF FAILURE IN SCHOOL IS THE MAIN THEME OF THIS PAMPHLET. THE DIFFERENT FORCES WHICH INFLUENCE THE SELF-IMAGES OF CHILDREN, THEIR SCHOOL PERFORMANCE, ACCEPTANCE OR REJECTION BY OTHER CHILDREN, AND, MOST IMPORTANT, ACCEPTANCE OR REJECTION BY THE TEACHER HERSELF, ARE DISCUSSED IN A GROUP OF PAPERS UNDER ELEVEN…

  3. Force dynamique des membranes fluides

    NASA Astrophysics Data System (ADS)

    Evans, Evan; Heinrich, Volkmar

    2003-03-01

    Rupturing fluid membrane vesicles with a steady ramp of micropipette suction yields a tension distribution that images the kinetic process of membrane failure. When plotted on a log scale of tension loading rate, the distribution peaks (membrane strengths) define a dynamic tension spectrum with distinct regimes that reflect passage of prominent energy barriers along the pathway to rupture. Demonstrated here by tests on giant PC lipid vesicles over loading rates from 0.06-60 mN/m/s, the stochastic process of rupture can be modelled as a causal sequence of two thermally-activated transitions where each transition governs membrane strength on separate scales of loading rate. Under fast ramps of tension, a steep linear regime appears in each spectrum at high strengths which implies that failure requires nucleation of a rare nanoscale defect. The slope and projected intercept yield defect size and spontaneous production rate respectively. However, under slow ramps of loading, the spectrum crosses over to a shallow-curved regime at lower strength, which is consistent with the kinetic impedance to opening an unstable hole in a fluid film. The dependence of rupture tension on rate reveals hole edge energy and frequency scale for thermal fluctuations in size. To cite this article: E. Evans, V. Heinrich, C. R. Physique 4 (2003).

  4. Localization of magma injections, hydrothermal alteration, and deformation in a volcanic detachment (Piton des Neiges, La Réunion)

    NASA Astrophysics Data System (ADS)

    Famin, Vincent; Berthod, Carole; Michon, Laurent; Eychenne, Julia; Brothelande, Elodie; Mahabot, Marie-Myriam; Chaput, Marie

    2016-11-01

    This contribution aims at understanding how magmatism, hydrothermal alteration, and deformation may have interacted to localize a detachment (a low-angle normal fault) in a basaltic volcano. Piton des Neiges, an inactive volcano of La Réunion Island, has been deeply cut by erosion, allowing its inner structure to be investigated. The deepest unit observed in the edifice is a kilometer-scale plutonic complex, the top of which is intruded by multiple sills. This zone of repeated sill intrusions has been interpreted as a detachment because it displays evidence of hydrothermal alteration in the greenschist facies linked to a brittle-ductile shear deformation. Deformation begins with cataclasis and is followed by mylonitization and chlorite crystallization, then by hydrofracturing and pumpellyite crystallization. Subsequent and post-deformation calcite crystallization occurs in voids such as fractures and vacuoles. Aluminium substitutions in chlorite suggest that the syn-deformation hydrothermal alteration did not exceed 250 °C and peaked in the deformation zone. Comparison of bulk-rock major element analyses of fresh, altered and deformed rocks shows that the zone of sill intrusion and deformation localized increased concentrations of P and K otherwise depleted in the footwall and hangingwall rocks, suggesting that the detachment acted as a trap for fluids. In contradiction with proposed models of volcano spreading, it is apparent that the portion of Piton des Neiges accessible to observation did not deform by creep of a large hydrothermal system or a plutonic complex below its solidus. Instead, the interface between the already cooled plutonic complex and the host rock acted as a brittle failure zone and was repeatedly intruded by magma injections. This localized heat source promoted hydrothermal alteration and low temperature creep in and around the discontinuity. The same process of magmatism-related weakening might occur on active volcanoes; it may, for instance

  5. Targeting Iron Deficiency Anemia in Heart Failure.

    PubMed

    Saraon, Tajinderpal; Katz, Stuart D

    2016-01-01

    Iron deficiency is common in heart failure (HF) patients, and is associated with increased risk of adverse clinical outcomes. Clinical trials of intravenous iron supplementation in iron-deficient HF patients have demonstrated short-term improvement in functional capacity and quality of life. In some trials, the benefits of iron supplementation were independent of the hemoglobin levels. Additional investigations of iron supplementation are needed to characterize the mechanisms contributing to clinical benefit and long-term safety in HF.

  6. The history of Werner Spalteholz's Handatlas der Anatomie des Menschen.

    PubMed

    Williams, D J

    1999-12-01

    Werner Spalteholz's Handatlas der Anatomie des Menschen is one of the most elegantly illustrated anatomical atlases of all time. Originally published in Leipzig as three volumes from 1895 to 1903, the atlas is still widely used and remains highly regarded by many. The atlas was remarkably popular during the first half of the 20th century, especially the English version in North America and the UK. Unfortunately, the original illustrations and printing plates for the work disappeared following the Second World War and their fate remains a mystery. And, in spite of the atlas's popularity, little is known to the men who prepared the artwork for Spalteholz. It is commonly believed that Max Brödel contributed illustrations to the atlas, but a close examination of the work does not confirm this. A century after its inception, Spalteholz's atlas remains a classic milestone in the history of anatomical illustration.

  7. Contribution de Ch.S. Draper a la connaissance des phenomenes vibratoires dans les foyers des moteurs et de reacteurs

    NASA Astrophysics Data System (ADS)

    Manson, N.

    The demonstration by Ch.S. Draper in 1934 of the existence and preponderant effects of transverse vibration modes of working gases in combustion chambers of piston engines during knocking is underlined. These modes were also later recognized as specific of detonation waves in gaseous mixtures, as well as of "high frequency" combustion instability in jet propulsion engines. Ch.S. Draper was the first to notice these transverse destructive vibratory phenomena in combustion chambers.

  8. Etude numerique et experimentale de la reponse vibro-acoustique des structures raidies a des excitations aeriennes et solidiennes

    NASA Astrophysics Data System (ADS)

    Mejdi, Abderrazak

    Les fuselages des avions sont generalement en aluminium ou en composite renforces par des raidisseurs longitudinaux (lisses) et transversaux (cadres). Les raidisseurs peuvent etre metalliques ou en composite. Durant leurs differentes phases de vol, les structures d'avions sont soumises a des excitations aeriennes (couche limite turbulente : TBL, champs diffus : DAF) sur la peau exterieure dont l'energie acoustique produite se transmet a l'interieur de la cabine. Les moteurs, montes sur la structure, produisent une excitation solidienne significative. Ce projet a pour objectifs de developper et de mettre en place des strategies de modelisations des fuselages d'avions soumises a des excitations aeriennes et solidiennes. Tous d'abord, une mise a jour des modeles existants de la TBL apparait dans le deuxieme chapitre afin de mieux les classer. Les proprietes de la reponse vibro-acoustique des structures planes finies et infinies sont analysees. Dans le troisieme chapitre, les hypotheses sur lesquelles sont bases les modeles existants concernant les structures metalliques orthogonalement raidies soumises a des excitations mecaniques, DAF et TBL sont reexamines en premier lieu. Ensuite, une modelisation fine et fiable de ces structures est developpee. Le modele est valide numeriquement a l'aide des methodes des elements finis (FEM) et de frontiere (BEM). Des tests de validations experimentales sont realises sur des panneaux d'avions fournis par des societes aeronautiques. Au quatrieme chapitre, une extension vers les structures composites renforcees par des raidisseurs aussi en composites et de formes complexes est etablie. Un modele analytique simple est egalement implemente et valide numeriquement. Au cinquieme chapitre, la modelisation des structures raidies periodiques en composites est beaucoup plus raffinee par la prise en compte des effets de couplage des deplacements planes et transversaux. L'effet de taille des structures finies periodiques est egalement pris en

  9. Matériaux pour la dépollution des gaz d'échappement automobile

    NASA Astrophysics Data System (ADS)

    Mouaddib-Moral, N.; Gauthier, C.

    2002-04-01

    Les premières législations antipollution ont été mises en place suite à la détection, aux Etats Unis plus particulièrement en Californie, du smog photochimique et des pluies acides, néfastes pour la faune et la flore. Les estimations de la contribution de l'automobile aux émissions de composés, considérés comme précurseurs de ces phénomènes, ont été suffisantes pour provoquer la mise en place de normes draconiennes en matière d'émissions automobiles. Les matériaux catalytiques ont été évalués en tant que solution possible pour réduire les émissions à l'échappement. En Europe, l'utilisation des catalyseurs trois voies a été généralisée sur les véhicules essence fonctionnant à richesse stoechiométrique à partir de 1993. Une nouvelle génération de catalyseurs appelée piège à oxydes d'azote (NOx) est maintenant nécessaire pour le post-traitement des gaz d'échappement des motorisations à essence fonctionnant en mélange pauvre (combustion en présence d'un excès d'oxygène) pour diminuer la consommation et par conséquent réduire les émissions du CO2 connu pour son impact sur l'effet de serre. La dépollution des moteurs diesel via un catalyseur d'oxydation a été généralisée en Europe depuis 1996. La sévérisation des normes européennes impose pour les moteurs diesel le recours à des matériaux spécifiques pour le traitement des oxydes d'azotes et des particules par l'intermédiaire de filtres à particules dont l'efficacité de filtration est supérieure à 95%, mais doivent subir des régénérations périodiques.

  10. Note des Éditeurs scientifiques

    NASA Astrophysics Data System (ADS)

    Averbuch, P.

    Cette série d'articles est une revue de résultats expérimentaux sur différents "fluides" moléculaires, dans lesquels la cohésion est due à des forces de Van der Waals et à des liaisons hydrogène, l'eau étant un de ces fluides. Ces résultats sont présentés de façon à justifier expérimentalement un modèle original, non extensif, des propriétés de ces fluides, et l'ensemble se présente sous la forme de trois articles décrivant le modèle, suivis chacun par un article le comparant aux résultats expérimentaux publiés par de nombreux auteurs. Le caractère non extensif des propriétés physiques des fluides est choquant, contraire à beaucoup d'idées établies, il semble n'avoir en sa faveur qu'un argument, la comparaison avec un nombre de résultats expérimentaux assez grand pour que l'effet du hasard soit difficilement soupçonnable. En particulier, les écarts entre des résultats de mesures faits par des auteurs différents dans des conditions différentes sont expliqués, le sérieux et la compétence des différents expérimentateurs ne sont plus mis en doute : mais l'interprétation de ces résultats avec un modèle extensif non adapté est seule mise en cause. Les modèles extensifs étant utilisés systématiquement, au delà des expériences de physiciens, dans les calculs d'ingénieurs, et dans la modélisation d'appareils qui fonctionnent et de phénomènes naturels observés par tout le monde, il fallait expliquer pourquoi on pouvait renoncer à l'extensivité. Les raisons du succès pratique des modèles extensifs sont données, d'abord dans le cas des nématiques, puis dans celui des liquides ordinaires, et c'est ce qui rend l'ensemble cohérent, tant avec les mesures physiques fines qu'avec les observations quotidiennes. Il n'en reste pas moins que si l'interprétation donnée dans cette série d'articles est généralisable, une justification théorique du modèle utilisé devient nécessaire. Pour ce qui est des propriétés d

  11. Les applications des faisceaux d'ions dans la physique des polymères

    NASA Astrophysics Data System (ADS)

    Ratier, B.; Moliton, A.; Lucas, B.; Guille, B.; Clamadieu, M.

    1998-06-01

    Experimental configurations of ions beams are illustrated by diagrams in the case of low energy implantation, Reactive Ion Beam Etching (RIBE), Ion Beam Assisted Deposition (IBAD) of molecular layers (or oligomers). Nous présentons les configurations expérimentales (illustrées par des schémas) de trois applications des faisceaux d'ions au traitement physique des polymères : dopage par implantation (cité pour mémoire), gravure par faisceaux d'ions réactifs (RIBE), dépôt des couches moléculaires (ou oligomères) assistés par faisceau (IBAD).

  12. La structure des liquides simples et des alliages liquides métalliques

    NASA Astrophysics Data System (ADS)

    Simonet, V.; Bellissent, R.

    2003-09-01

    De par le caractère isotrope des interactions et leur courte portée, les liquides métalliques ont longtemps été considérés comme des systèmes modèles pouvant être décrits par un arrangement aléatoire de sphères dures. Ceci a été confirmé par l'allure des premières fonctions de distribution de paires déterminées par diffusion de RX ou de neutrons à la précision près des expériences de l'époque. Néanmoins, cette image a tout d'abord été révisée pour le cas des alliages métalliques dont les fonctions de distribution de paires ont révélé un ordre local plus complexe à cause des affinités chimiques entre espèces différentes. Grâce à la possibilité actuelle de mesurer des facteurs de structure de bien meilleure qualité, la question de la nature de l'ordre local et du degré d'isotropie des interactions peut se poser même dans le cas des liquides simples ou dans le cas d'alliages présentant à priori peu d'ordre chimique. Dans ce cadre, l'ordre local icosaédrique est particulièrement intéressant puisque l'icosaèdre est un agrégat très compact et, bien que présentant des liaisons directionnelles, très proche d'une configuration isotrope. La mise en évidence de ce type d'ordre local est présentée pour deux types de liquides : les liquides surfondus dans lesquels un ordre local icosaédrique a été prédit pour expliquer les propriétés de surfusion, et les liquides en équilibre avec des quasicristaux qui présentent un ordre local icosaédrique.

  13. Dynamic failure in brittle solids

    SciTech Connect

    Grady, D.E.

    1994-04-01

    Failure of brittle solids within the extremes of the shock loading environment is not well understood. Recent shock-wave data on compression shear failure and tensile spall failure for selected high-strength ceramics are presented and used to examine the mechanisms of dynamic failure. Energy-based theories are used to bound the measured strength properties. A new concept of failure waves in brittle solids is explored in light of the kinetic processes of high-rate fracture. Classical failure criteria are compared with the present base of dynamic strength data on ceramics.

  14. Market failure, policy failure and other distortions in chronic disease markets

    PubMed Central

    Watts, Jennifer J; Segal, Leonie

    2009-01-01

    Background The increasing prevalence of chronic disease represents a significant burden on most health systems. This paper explores the market failures and policy failures that exist in the management of chronic diseases. Discussion There are many sources of market failure in health care that undermine the efficiency of chronic disease management. These include incomplete information as well as information asymmetry between providers and consumers, the effect of externalities on consumer behaviour, and the divergence between social and private time preference rates. This has seen government and policy interventions to address both market failures and distributional issues resulting from the inability of private markets to reach an efficient and equitable distribution of resources. However, these have introduced a series of policy failures such as distorted re-imbursement arrangements across modalities and delivery settings. Summary The paper concludes that market failure resulting from a preference of individuals for 'immediate gratification' in the form of health care and disease management, rather than preventative services, where the benefits are delayed, has a major impact on achieving an efficient allocation of resources in markets for the management of chronic diseases. This distortion is compounded by government health policy that tends to favour medical and pharmaceutical interventions further contributing to distortions in the allocation of resources and inefficiencies in the management of chronic disease. PMID:19534822

  15. Developpement des betons semi autoplacants a rheologie adaptee pour des infrastructures

    NASA Astrophysics Data System (ADS)

    Sotomayor Cruz, Cristian Daniel

    Au cours des dernières décennies, les infrastructures canadiennes et québécoises comportent plusieurs structures en béton armé présentant des problèmes de durabilité dus aux conditions climatiques sévères, à la mauvaise conception des structures, à la qualité des matériaux, aux types des bétons choisis, aux systèmes de construction ou à l'existence d'événements incontrôlables. En ce qui concerne le choix du béton pour la construction des infrastructures, une vaste gamme de béton divisée en deux principaux types peut être utilisée: le béton conventionnel vibré (BCV) et le béton autoplaçant (BAP). Dans le cas d'un BCV, la consolidation inadéquate par vibration a été un problème récurrent, occasionnant des dommages structuraux. Ceci a conduit à une réduction de la durabilité et à une augmentation du coût d'entretien et de réparation des infrastructures. Rien que l'utilisation d'un BAP a des avantages tels que l'élimination de la vibration, la réduction des coûts de main d'oeuvre et l'amélioration de la qualité des structures, néanmoins, le coût initial d'un BAP par rapport à un BCV ne permet pas encore de généraliser son utilisation dans l'industrie de la construction. Ce mémoire présente la conception d'une nouvelle gamme de béton semi-autoplaçant pour la construction des infrastructures (BSAP-I) exigeant une vibration minimale. Il s'agit de trouver un équilibre optimal entre la rhéologie et le coût initial du nouveau béton pour conférer une bonne performance structurale et économique aux structures. Le programme expérimental établi a premièrement permis d'évaluer la faisabilité d'utilisation des BSAP-I pour la mise en place des piliers d'une infrastructure de pont à Sherbrooke. En plus, l'utilisation d'un plan d'expériences a permis l'évaluation de trois paramètres de formulation sur les propriétés des mélanges de BSAP-I à l'état frais et durci. Finalement, l'évaluation de la performance des

  16. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    NASA Astrophysics Data System (ADS)

    Bendaoud, Adlane Larbi

    Les evaporateurs de refrigeration sont surtout du type tube a ailettes, appeles serpentins, et fonctionnent dans l'une des conditions suivantes: seche, humide ou avec formation de givre. Il a ete demontre que la formation du givre sur la paroi exterieure de l'echangeur engendre une surconsommation energetique a cause des operations de degivrage puisque 15 a 20% seulement de la chaleur produite sert au degivrage tandis que le reste est dissipee dans l'environnement [1]. Avec l'avenement des nouveaux refrigerants, moins nocifs envers l'environnement, l'industrie du froid se trouve penalisee du fait que peu ou pas de composantes mecaniques (compresseur, pompe, echangeur...etc.) adaptees sont disponibles [3]. Il s'agit pour la communaute des frigoristes de combler ce retard technologique en redeveloppant ces composantes mecaniques afin qu'elles soient adaptees aux nouveaux refrigerants. Dans cette optique, et afin de mieux comprendre le comportement thermique des evaporateurs au CO2 fonctionnant dans des conditions seches, qu'un groupe de chercheurs du CanmetENERGIE avaient lance, en 2000, un programme de R & D. Dans le cadre de programme un outil de simulation des evaporateurs au CO2 a ete developpe et un banc d'essai contenant une boucle secondaire de refrigeration utilisant le CO2 comme refrigerant a ete construit. Comme continuite de ce travail de recherche, en 2006 ce meme groupe de recherche a lance un nouveau projet qui consiste a faire une etude theorique et experimentale des evaporateurs au CO2 operants dans des conditions de givrage. Et, c'est exactement dans le cadre de ce projet que se positionne ce travail de these. Ce travail de recherche a ete entrepris pour mieux comprendre le comportement thermique et hydrodynamique des serpentins fonctionnant dans des conditions de givrage, l'effet des circuits de refrigerant ainsi que celui des parametres geometriques et d'operation. Pour cela, un travail theorique supporte par une etude experimentale a ete effectue

  17. Impacts of Gender Differences on Conducting Operational Activities (Impact des diffrenes homme/femme sur la conduite des activites oprationnelles)

    DTIC Science & Technology

    2008-10-01

    MP-HFM-158 Impacts of Gender Differences on Conducting Operational Activities (Impact des différences homme/ femme sur la conduite des activités...harassment should also be dealt with on a multicultural basis. ES - 2 RTO-MP-HFM-158 Impact des différences homme/ femme sur la...conduite des activités opérationnelles (RTO-MP-HFM-158) Synthèse L’intégration des femmes dans les armées, se fait à un rythme variable dans les

  18. Long term dismantling of a basaltic volcano (Piton des Neiges, La Réunion hotspot).

    NASA Astrophysics Data System (ADS)

    Chaput, Marie; Famin, Vincent; Michon, Laurent; Catry, Thibault

    2010-05-01

    been affected by an extensional deformation oriented N-S, characterized by a similar combination of slow deformations and rapid flank failure (Famin and Michon, 2009). Two directions of flank destabilization consistent with debris avalanche flow directions, can thus be distinguished on the Piton des Neiges volcano by structural investigations: the N120 deformation in Cilaos and the N-S deformation in Salazie. Our structural study also reveals that the stress field within a volcanic edifice is complex and evolves with time throughout the life of a basaltic volcano.

  19. Effets des electrons secondaires sur l'ADN

    NASA Astrophysics Data System (ADS)

    Boudaiffa, Badia

    Les interactions des electrons de basse energie (EBE) representent un element important en sciences des radiations, particulierement, les sequences se produisant immediatement apres l'interaction de la radiation ionisante avec le milieu biologique. Il est bien connu que lorsque ces radiations deposent leur energie dans la cellule, elles produisent un grand nombre d'electrons secondaires (4 x 104/MeV), qui sont crees le long de la trace avec des energies cinetiques initiales bien inferieures a 20 eV. Cependant, il n'y a jamais eu de mesures directes demontrant l'interaction de ces electrons de tres basse energie avec l'ADN, du principalement aux difficultes experimentales imposees par la complexite du milieu biologique. Dans notre laboratoire, les dernieres annees ont ete consacrees a l'etude des phenomenes fondamentaux induits par impact des EBE sur differentes molecules simples (e.g., N2, CO, O2, H2O, NO, C2H 4, C6H6, C2H12) et quelques molecules complexes dans leur phase solide. D'autres travaux effectues recemment sur des bases de l'ADN et des oligonucleotides ont montre que les EBE produisent des bris moleculaires sur les biomolecules. Ces travaux nous ont permis d'elaborer des techniques pour mettre en evidence et comprendre les interactions fondamentales des EBE avec des molecules d'interet biologique, afin d'atteindre notre objectif majeur d'etudier l'effet direct de ces particules sur la molecule d'ADN. Les techniques de sciences des surfaces developpees et utilisees dans les etudes precitees peuvent etre etendues et combinees avec des methodes classiques de biologie pour etudier les dommages de l'ADN induits par l'impact des EBE. Nos experiences ont montre l'efficacite des electrons de 3--20 eV a induire des coupures simple et double brins dans l'ADN. Pour des energies inferieures a 15 eV, ces coupures sont induites par la localisation temporaire d'un electron sur une unite moleculaire de l'ADN, ce qui engendre la formation d'un ion negatif transitoire

  20. Autoimmune premature ovarian failure

    PubMed Central

    2017-01-01

    Premature ovarian failure (POF), also termed as primary ovarian insufficiency (POI), is a highly heterogenous condition affecting 0.5-3.0% of women in childbearing age. These young women comprise quite a formidable group with unique physical and psychological needs that require special attention. Premature ovarian senescence (POS) in all of its forms evolves insidiously as a basically asymptomatic process, leading to complete loss of ovarian function, and POI/POF diagnoses are currently made at relatively late stages. Well-known and well-documented risk factors exist, and the presence or suspicion of autoimmune disorder should be regarded as an important one. Premature ovarian failure is to some degree predictable in its occurrence and should be considered while encountering young women with loss of menstrual regularity, especially when there is a concomitant dysfunction in the immune system. PMID:28250725

  1. Anemia and heart failure.

    PubMed

    O'Meara, Eileen; Murphy, Clare; McMurray, John J V

    2004-12-01

    Over the past few years, anemia has emerged as a powerful independent predictor of adverse outcomes in chronic heart failure (CHF). It affects up to 50% of patients with CHF, depending on the definition of anemia used and on the population studied. Even small reductions in hemoglobin are associated with worse outcome. However, the causes of anemia in CHF remain unclear, although impairment of renal function and inflammatory cytokines are proposed mechanisms. Both may act through impairment of the synthesis or action of erythropoietin. Preliminary studies have demonstrated improvement in symptoms, exercise tolerance, quality of life, and reductions in hospitalizations when patients with severe CHF were treated with erythropoietin. The benefits and the potential risks of such therapies will be further addressed in upcoming larger randomized trials. The recent interest in anemia reflects a new perspective in heart failure therapy, focusing on non-cardiovascular comorbidities.

  2. DES Science Portal: Computing Photometric Redshifts

    SciTech Connect

    Gschwend, Julia

    2016-01-01

    An important challenge facing photometric surveys for cosmological purposes, such as the Dark Energy Survey (DES), is the need to produce reliable photometric redshifts (photo-z). The choice of adequate algorithms and configurations and the maintenance of an up-to-date spectroscopic database to build training sets, for example, are challenging tasks when dealing with large amounts of data that are regularly updated and constantly growing. In this paper, we present the first of a series of tools developed by DES, provided as part of the DES Science Portal, an integrated web-based data portal developed to facilitate the scientific analysis of the data, while ensuring the reproducibility of the analysis. We present the DES Science Portal photometric redshift tools, starting from the creation of a spectroscopic sample to training the neural network photo-z codes, to the final estimation of photo-zs for a large photometric catalog. We illustrate this operation by calculating well calibrated photo-zs for a galaxy sample extracted from the DES first year (Y1A1) data. The series of processes mentioned above is run entirely within the Portal environment, which automatically produces validation metrics, and maintains the provenance between the different steps. This system allows us to fine tune the many steps involved in the process of calculating photo-zs, making sure that we do not lose the information on the configurations and inputs of the previous processes. By matching the DES Y1A1 photometry to a spectroscopic sample, we define different training sets that we use to feed the photo-z algorithms already installed at the Portal. Finally, we validate the results under several conditions, including the case of a sample limited to i<22.5 with the color properties close to the full DES Y1A1 photometric data. This way we compare the performance of multiple methods and training configurations. The infrastructure presented here is an effcient way to test several methods of

  3. Triggers of State Failure

    DTIC Science & Technology

    2010-03-01

    forms, and is limited to the most acute cases of state failure in which the apparatus of the state collapses. A state trying, and failing, to provide...and the writ of government does not practically extend beyond the city limits of the capital. A failing state may be on the trend towards collapse...provide reasonable accuracy in post-dictive analysis, but are of limited use for short-term predictions as changes do not happen quickly, not are they

  4. Observing a failure

    NASA Astrophysics Data System (ADS)

    David, Leonard

    1994-06-01

    Mars Observer was being sent to 'rewrite the book on Mars.' That was the claim of one NASA scientist as the interplanetary robot sat atop a Titan 3 booster that roared skyward from a Cape Canaveral launch pad. On August 21, 1993, only three days before entering Mars orbit, America's first mission to Mars in 17 years fell silent. This article reviews possible causes of this failure.

  5. Fiabilité des structures mécaniques adaptatives: effet de la panne des actionneurs ou des capteurs sur la stabilité

    NASA Astrophysics Data System (ADS)

    Fall, H.; Charon, W.; Kouta, R.

    2002-12-01

    Ces dernières décennies, des activités significatives dans le monde étaient dirigées autour du contrôle actif. Le but de ces recherches était essentiellement d'améliorer les performances, la fiabilité et la sécurité des systèmes. Notamment dans le cas des structures soumises à des vibrations aléatoires. D'importants travaux ont été consacré à l'utilisation des “matériaux intelligents” comme capteurs et actionneurs. Cette article propose l'analyse de la fiabilité des systèmes mécaniques en étudiant les pannes des actionneurs ou des capteurs. L'effet de ces pannes sur la stabilité et la performance du système y est démontré. Les méthodologies de conception y sont rappelées. Des exemples numériques sont fournis à travers le contrôle d'un panneau sous chargement dynamique pour illustrer la méthode proposée.

  6. [Obesity and heart failure].

    PubMed

    Weismann, D; Wiedmann, S; Bala, M; Frantz, S; Fassnacht, M

    2015-02-01

    Obesity is an important risk factor for the development of heart failure. In normotensive obese patients, a reduced peripheral resistance is typically observed and is accompanied by an increased fluid volume and an increase in cardiac work, resulting in hypertrophy and diastolic heart failure, which can be visualized with echocardiography. However, in the presence of arterial hypertension cardiac geometry is not different to hypertensive heart disease without obesity. Furthermore, the typical changes found with obesity, such as reduced peripheral resistance and increased blood volume, are no longer present. Obstructive sleep apnea (OSA) is very common in obesity and warrants screening but levels of the heart failure marker N-terminal pro-brain natriuretic peptide (NT-ProBNP) might be misleading as the values are lower in obesity than in normal weight controls. Body weight reduction is advisable but difficult to achieve and much more difficult to maintain. Furthermore, diet and exercise has not been proven to enhance life expectancy in obesity. However, with bariatric surgery, long-term weight reduction can be achieved and mortality can be reduced. With effective weight loss and improved clinical outcome after bariatric surgery, treatment of obesity has shifted much more into focus. Regardless of technical challenges in the work-up of obese patients, clinical symptoms suggestive of cardiac disorders warrant prompt investigation with standard techniques following recommendations as established for normal weight patients.

  7. Pharmacogenetics of Heart Failure

    PubMed Central

    Mestroni, Luisa; Begay, Rene; Graw, Sharon L; Taylor, Matthew RG

    2014-01-01

    Purpose of Review Novel medical approaches and personalized medicine seek to use genetic information to “individualize” and improve diagnosis, prevention, and therapy. The personalized management of cardiovascular disease involves a large spectrum of potential applications, from diagnostics of monogenic disorders, to prevention and management strategies based on modifier genes, to pharmacogenetics in which individual genetic information is used to optimize pharmacological treatments. Recent Findings Evidence suggests that common polymorphic variants of modifier genes could influence drug response in cardiovascular disease in a variety of areas including heart failure, arrhythmias, dyslipidemia and hypertension. In heart failure, common genetic variants of beta-adrenergic receptors, alpha-adrenergic receptors, and endothelin receptors (among others) have been associated with variable response to heart failure therapies. The challenge remains to develop strategies to leverage this information in ways that personalize and optimize cardiovascular therapy based on a patient's genetic profile. Summary While advances in technologies will continue to transition personalized medicine from the research to the clinical setting, health care providers will need to reshape clinical diagnostic paradigms. Ultimately, pharmacogenetics will give providers options for improving patient management on the basis of pharmacogenetic data. PMID:24717669

  8. Pharmacogenetics of heart failure.

    PubMed

    Mestroni, Luisa; Begay, Rene L; Graw, Sharon L; Taylor, Matthew R G

    2014-05-01

    Novel medical approaches and personalized medicine seek to use genetic information to 'individualize' and improve diagnosis, prevention, and therapy. The personalized management of cardiovascular disease involves a large spectrum of potential applications, from diagnostics of monogenic disorders, to prevention and management strategies based on modifier genes, to pharmacogenetics, in which individual genetic information is used to optimize the pharmacological treatments. Evidence suggests that the common polymorphic variants of modifier genes could influence drug response in cardiovascular disease in a variety of areas, including heart failure, arrhythmias, dyslipidemia, and hypertension. In heart failure, common genetic variants of β-adrenergic receptors, α-adrenergic receptors, and endothelin receptors (among others) have been associated with variable response to heart failure therapies. The challenge remains to develop strategies to leverage this information in ways that personalize and optimize cardiovascular therapy based on a patient's genetic profile. Although advances in technologies will continue to transition personalized medicine from the research to the clinical setting, healthcare providers will need to reshape the clinical diagnostic paradigms. Ultimately, pharmacogenetics will give providers the options for improving patient management on the basis of pharmacogenetic data.

  9. Reducing Failures in Reference Service.

    ERIC Educational Resources Information Center

    Douglas, Ian

    1988-01-01

    Summarizes the results of 11 selected studies of the accuracy of reference services and identifies six modes of failure of reference services. Methods of detecting and reducing failure in each of these modes are then discussed. (17 references) (MES)

  10. Drug Treatment of Cardiac Failure

    PubMed Central

    Achong, M. R.; Kumana, C. R.

    1982-01-01

    Treatment of cardiac failure should first be aimed at reversing or ameliorating the underlying pathological processes. This review highlights the common problems and pitfalls in the use of digoxin, diuretics and vasodilators in patients with cardiac failure. PMID:21289849

  11. Saturn component failure rate and failure rate modifiers

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Failure mode frequency ratios, environmental adjustment factors, and failure rates for mechanical and electromechanical component families are presented. The failure rates and failure rate modifiers resulted from a series of studies whose purpose was to provide design, tests, reliability, and systems engineers with accurate, up-to-date failure rate information. The results of the studies were achieved through an extensive engineering analysis of the Saturn Program test data and Unsatisfactory Condition Reports (UCR's) and the application of mathematical techniques developed for the studies.

  12. Improving Patient Outcomes With Oral Heart Failure Medications.

    PubMed

    Sherrod, Melissa M; Cheek, Dennis J; Seale, Ashlie

    2016-05-01

    Hospitals are under immense pressure to reduce heart failure readmissions that occur within 30 days of discharge, and to improve the quality of care for these patients. Penalties mandated by the Affordable Care Act decrease hospital reimbursement and ultimately the overall cost of caring for these patients increases if they are not well managed. Approximately 25% of patients hospitalized for heart failure are at high risk for readmission and these rates have not changed over the past decade. As a result of an aging population, the incidence of heart failure is expected to increase to one in five Americans over the age of 65. Pharmacologic management can reduce the risk of death and help prevent unnecessary hospitalizations. Healthcare providers who have knowledge of heart failure medications and drug interactions and share this information with their patients contribute to improved long-term survival and physical functioning as well as fewer hospitalizations and a delay of progressive worsening of heart failure.

  13. Anemia associated with chronic heart failure: current concepts

    PubMed Central

    Shah, Ravish; Agarwal, Anil K

    2013-01-01

    Anemia is a frequent comorbidity of heart failure and is associated with poor outcomes. Anemia in heart failure is considered to develop due to a complex interaction of iron deficiency, kidney disease, and cytokine production, although micronutrient insufficiency and blood loss may contribute. Currently, treatment of anemia of heart failure lacks clear targets and specific therapy is not defined. Intravenous iron use has been shown to benefit anemic as well as nonanemic patients with heart failure. Treatment with erythropoietin-stimulating agents has been considered alone or in combination with iron, but robust evidence to dictate clear guidelines is not currently available. Available and emerging new agents in the treatment of anemia of heart failure will need to be tested in randomized, controlled studies. PMID:23403618

  14. Anemia associated with chronic heart failure: current concepts.

    PubMed

    Shah, Ravish; Agarwal, Anil K

    2013-01-01

    Anemia is a frequent comorbidity of heart failure and is associated with poor outcomes. Anemia in heart failure is considered to develop due to a complex interaction of iron deficiency, kidney disease, and cytokine production, although micronutrient insufficiency and blood loss may contribute. Currently, treatment of anemia of heart failure lacks clear targets and specific therapy is not defined. Intravenous iron use has been shown to benefit anemic as well as nonanemic patients with heart failure. Treatment with erythropoietin-stimulating agents has been considered alone or in combination with iron, but robust evidence to dictate clear guidelines is not currently available. Available and emerging new agents in the treatment of anemia of heart failure will need to be tested in randomized, controlled studies.

  15. Constructive Failure in Mathematics Classes

    ERIC Educational Resources Information Center

    Rowlett, Joel E.

    2011-01-01

    Great strides in the real world are usually accompanied by failure. Mathematics teachers should accept some failure as their students take risks during mathematical explorations. This is not to imply that students should fail an entire course, but they should have opportunities to take risks that may lead to failure, especially in the area of…

  16. Your Heart Failure Healthcare Team

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Your Heart Failure Healthcare Team Updated:Sep 28,2016 Patients with ... to the Terms and Conditions and Privacy Policy Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  17. Warning Signs of Heart Failure

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Warning Signs of Heart Failure Updated:Feb 9,2017 By themselves, any one ... faster. This content was last reviewed April 2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  18. Effet de la composition des materiaux composites sur la caracterisation et detection par ondes de Lamb

    NASA Astrophysics Data System (ADS)

    Ostiguy, Pierre-Claude

    Les matériaux composites sont de plus en plus utilisés en aéronautique. Leurs excellentes propriétés mécaniques et leur faible poids leur procurent un avantage certain par rapport aux matériaux métalliques. Ceux-ci étant soumis à diverses conditions de chargement et environnementales, ils sont suceptibles de subir plusieurs types d'endommagements, compromettant leur intégrité. Des méthodes fiables d'inspection sont donc nécessaires pour évaluer leur intégrité. Néanmoins, peu d'approches non destructives, embarquées et efficaces sont présentement utilisées. Ce travail de recherche se penche sur l'étude de l'effet de la composition des matériaux composites sur la détection et la caractérisation par ondes guidées. L'objectif du projet est de développer une approche de caractérisation mécanique embarquée permettant d'améliorer la performance d'une approche d'imagerie par antenne piézoélectriques sur des structures composite et métalliques. La contribution de ce projet est de proposer une approche embarquée de caractérisation mécanique par ultrasons qui ne requiert pas une mesure sur une multitude d'échantillons et qui est non destructive. Ce mémoire par articles est divisé en quatre parties, dont les parties deux A quatre présentant les articles publiés et soumis. La première partie présente l'état des connaissances dans la matière nécessaires à l'acomplissement de ce projet de maîtrise. Les principaux sujets traités portent sur les matériaux composites, propagation d'ondes, la modélisation des ondes guidées, la caractérisation par ondes guidées et la surveillance embarquée des structures. La deuxième partie présente une étude de l'effet des propriétés mécaniques sur la performance de l'algorithme d'imagerie Excitelet. L'étude est faite sur une structure isotrope. Les résultats ont démontré que l'algorithme est sensible à l'exactitude des propriétés mécaniques utilisées dans le modèle. Cette

  19. Use of DES Modeling for Determining Launch Availability for SLS

    NASA Technical Reports Server (NTRS)

    Watson, Mike; Staton, Eric; Cates, Grant; Finn, Ron; Altino, Karen; Burns, Lee

    2014-01-01

    The National Aeronautics and Space Administration (NASA) is developing new capabilities for human and scientific exploration beyond Earth's orbit. This effort includes the Space Shuttle derived Space Launch System (SLS), the Multi-Purpose Crew Vehicle (MPCV) "Orion", and the Ground Systems Development and Operations (GSDO). There are several requirements and Technical Performance Measures (TPMs) that have been levied by the Exploration Systems Development (ESD) upon the SLS, MPCV, and GSDO Programs including an integrated Launch Availability (LA) TPM. The LA TPM is used to drive into the SLS, Orion and GSDO designs a high confidence of successfully launching exploration missions that have narrow Earth departure windows. The LA TPM takes into consideration the reliability of the overall system (SLS, Orion and GSDO), natural environments, likelihood of a failure, and the time required to recover from an anomaly. A challenge with the LA TPM is the interrelationships between SLS, Orion, GSDO and the natural environments during launch countdown and launch delays that makes it impossible to develop an analytical solution for calculating the integrated launch probability. This paper provides an overview of how Discrete Event Simulation (DES) modeling was used to develop the LA TPM, how it was allocated down to the individual programs, and how the LA analysis is being used to inform and drive the SLS, Orion, and GSDO designs to ensure adequate launch availability for future human exploration.

  20. Use of DES Modeling for Determining Launch Availability for SLS

    NASA Technical Reports Server (NTRS)

    Staton, Eric; Cates, Grant; Finn, Ronald; Altino, Karen M.; Burns, K. Lee; Watson, Michael D.

    2014-01-01

    The National Aeronautics and Space Administration (NASA) is developing new capabilities for human and scientific exploration beyond Earth's orbit. This effort includes the Space Shuttle derived Space Launch System (SLS), the Orion Multi-Purpose Crew Vehicle (MPCV), and the Ground Systems Development and Operations (GSDO). There are several requirements and Technical Performance Measures (TPMs) that have been levied by the Exploration Systems Development (ESD) upon the SLS, Orion, and GSDO Programs including an integrated Launch Availability (LA) TPM. The LA TPM is used to drive into the SLS, Orion and GSDO designs a high confidence of successfully launching exploration missions that have narrow Earth departure windows. The LA TPM takes into consideration the reliability of the overall system (SLS, Orion and GSDO), natural environments, likelihood of a failure, and the time required to recover from an anomaly. A challenge with the LA TPM is the interrelationships between SLS, Orion, GSDO and the natural environments during launch countdown and launch delays that makes it impossible to develop an analytical solution for calculating the integrated launch probability. This paper provides an overview of how Discrete Event Simulation (DES) modeling was used to develop the LA TPM, how it was allocated down to the individual programs, and how the LA analysis is being used to inform and drive the SLS, Orion, and GSDO designs to ensure adequate launch availability for future human exploration.

  1. Determination des Parametres Atmospheriques des Etoiles Naines Blanches de Type DB

    NASA Astrophysics Data System (ADS)

    Beauchamp, Alain

    1995-01-01

    Les etoiles naines blanches dont les spectres visibles sont domines par des raies fortes d'helium neutre sont subdivisees en trois classes, DB (raies d'helium neutre seulement), DBA (raies d'helium neutre et d'hydrogene) et DBZ (raies d'helium neutre et d'elements lourds). Nous analysons trois echantillons de spectres observes de ces types de naines blanches. Les echantillons consistent, respectivement, de 48 spectres dans le domaine du visible (3700-5100 A). 24 dans l'ultraviolet (1200-3100 A) et quatre dans la partie rouge du visible (5100-6900) A). Parmi les objets de l'echantillon visible, nous identifions quatre nouvelles DBA, ainsi que deux nouvelles DBZ, auparavant classees DB. L'analyse nous permet de determiner spectroscopiquement les parametres atmospheriques, soit la temperature effective, la gravite de surface, ainsi que l'abondance relative de l'hydrogene, N(H)/N(He), dans le cas des DBA. Pour les objets plus chauds que ~15,000 K, la gravite de surface determinee est fiable, et nous obtenons les masses stellaires avec une relation masse -rayon theorique. Les exigences propres a l'analyse de ces objets ont requis d'importantes ameliorations dans la modelisation de leurs atmospheres et distributions de flux de radiation emis par ces derniers. Nous avons inclus dans les modeles d'atmospheres, pour la premiere fois a notre connaissance, les effets dus a la molecule He_sp{2 }{+}, ainsi que l'equation d'etat de Hummer et Mihalas (1988), qui tient compte des perturbations entre particules dans le calcul des populations des differents niveaux atomiques. Nous traitons la convection dans le cadre de la theorie de la longueur de melange. Trois grilles de modeles d'atmospheres a l'ETL (equilibre thermodynamique local) ont ete produites, pour un ensemble de temperatures effectives, gravites de surface et abondances d'hydrogene couvrant les proprietes des etoiles de nos echantillons; elles sont caracterisees par differentes parametrisations appelees, respectivement

  2. [Acute renal failure: a rare presentation of Addison's disease].

    PubMed

    Salhi, Houda

    2016-01-01

    Addison's disease is a rare condition. Its onset of symptoms most often is nonspecific contributing to a diagnostic and therapeutic delay. Acute renal failure can be the first manifestation of this disease. We report the case of a patient with Addison's disease who was initially treated for acute renal failure due to multiple myeloma and whose diagnosis was adjusted thereafter. Patient's condition dramatically improved after treatment with intravenous rehydration; injectable hydrocortisone.

  3. Profil epidemiologique des brulures d'enfants admis au Centre National des Brules, Maroc

    PubMed Central

    Zahid, A.; Atannaz, J.; Alaoui, M.; Rafik, A.; Ezzoubi, M.; Diouri, M.; Chlihi, A.; Bahechar, N.; Boukind, E.H.

    2011-01-01

    Summary Ce travail rétrospectif analyse les particularités épidémiologiques de 543 cas de brûlures d'enfants, représentant 45,7% des admissions de notre centre, en vue de déterminer les éléments pouvant contribuer à renforcer la prévention, qui reste le traitement de choix de cette pathologie. La moyenne d'âge est de 4,25 ans avec une prédilection pour la tranche d'âge d'un à cinq ans, avec 42,5% des cas. Une atteinte masculine est retrouvée dans 63,5% des cas. La brûlure survient à domicile dans 85,1% et accidentellement dans 95% des cas. Les brûlures thermiques représentent 96,5% des causes dominées par les liquides dans 69,3% des cas. La surface cutanée brûlée est ≥ 20% dans 52,3%. La brûlure intéresse essentiellement les membres supérieurs (79,1%). 56,8% des enfants sont transférés par d'autres hôpitaux et le délai de prise en charge hospitalière est supérieur à 6 heures dans 65,5%. Le taux de mortalité a été de 13,2%. PMID:22639559

  4. Intercellular communication lessons in heart failure.

    PubMed

    Bang, Claudia; Antoniades, Charalambos; Antonopoulos, Alexios S; Eriksson, Ulf; Franssen, Constantijn; Hamdani, Nazha; Lehmann, Lorenz; Moessinger, Christine; Mongillo, Marco; Muhl, Lars; Speer, Thimoteus; Thum, Thomas

    2015-11-01

    Cell-cell or inter-organ communication allows the exchange of information and messages, which is essential for the coordination of cell/organ functions and the maintenance of homeostasis. It has become evident that dynamic interactions of different cell types play a major role in the heart, in particular during the progression of heart failure, a leading cause of mortality worldwide. Heart failure is associated with compensatory structural and functional changes mostly in cardiomyocytes and cardiac fibroblasts, which finally lead to cardiomyocyte hypertrophy and fibrosis. Intercellular communication within the heart is mediated mostly via direct cell-cell interaction or the release of paracrine signalling mediators such as cytokines and chemokines. However, recent studies have focused on the exchange of genetic information via the packaging into vesicles as well as the crosstalk of lipids and other paracrine molecules within the heart and distant organs, such as kidney and adipose tissue, which might all contribute to the pathogenesis of heart failure. In this review, we discuss emerging communication networks and respective underlying mechanisms which could be involved in cardiovascular disease conditions and further emphasize promising therapeutic targets for drug development. © 2015 The Authors European Journal of Heart Failure © 2015 European Society of Cardiology.

  5. Electrophysiological Remodeling in Heart Failure

    PubMed Central

    Wang, Yanggan; Hill, Joseph A.

    2010-01-01

    Heart failure affects nearly 6 million Americans, with a half-million new cases emerging each year. Whereas up to 50% of heart failure patients die of arrhythmia, the diverse mechanisms underlying heart failure-associated arrhythmia are poorly understood. As a consequence, effectiveness of antiarrhythmic pharmacotherapy remains elusive. Here, we review recent advances in our understanding of heart failure-associated molecular events impacting the electrical function of the myocardium. We approach this from an anatomical standpoint, summarizing recent insights gleaned from pre-clinical models and discussing their relevance to human heart failure. PMID:20096285

  6. La microscopie ionique analytique des tissus biologiques

    NASA Astrophysics Data System (ADS)

    Galle, P.

    Proposed in 1960 by R. Castaing and G. Slodzian, secondary ion emission microanalysis is a microanalytical method which is now largely used for the study of inert material. The instrument called the analytical ion microscope can also be used for the study of biological spécimens ; images representing the distribution of a given stable or radioactive isotope in a tissue section are obtained with a resolution of 0.5 μm. Among the characteristics of this method, two are of particular interest in biological research : its capacity for isotopic analysis and its very high sensitivity which makes possible for the first time a chemical analysis of element at a very low or even at a trace concentration in a microvolume. Proposé en 1960 par R. Castaing et G. Slodzian, la microanalyse par émission ionique secondaire est une méthode qui permet, entre autre, d'obtenir des images représentant la distribution des isotopes présents à la surface d'un échantillon solide avec une résolution de 0,5 μm. D'intérêt très général, cette méthode a été d'abord largement utilisée pour l'étude des matériaux inertes. Elle offre en outre des possibilités entièrement nouvelles dans le domaine de la recherche biomédicale. L'instrument réalisé, le microscope ionique analytique présente deux caractéristiques particulièrement intéressantes pour la biologie : la possibilité d'analyse isotopique, et l'extrême sensibilité permettant de détecter et de localiser dans une coupe histologique des éléments à des concentrations très faibles voire à l'état de trace.

  7. Les effets des interfaces sur les proprietes magnetiques et de transport des multicouches nickel/iron et cobalt/silver

    NASA Astrophysics Data System (ADS)

    Veres, Teodor

    Cette these est consacree a l'etude de l'evolution structurale des proprietes magnetiques et de transport des multicouches Ni/Fe et nanostructures a base de Co et de l'Ag. Dans une premiere partie, essentiellement bibliographique, nous introduisons quelques concepts de base relies aux proprietes magnetiques et de transport des multicouches metalliques. Ensuite, nous presentons une breve description des methodes d'analyse des resultats. La deuxieme partie est consacree a l'etude des proprietes magnetiques et de transport des multicouches ferromagnetiques/ferromagnetiques Ni/Fe. Nous montrerons qu'une interpretation coherente de ces proprietes necessite la prise en consideration des effets des interfaces. Nous nous attacherons a mettre en evidence, a evaluer et a etudier les effets de ces interfaces ainsi que leur evolution, et ce, suite a des traitements thermiques tel que le depot a temperature elevee et l'irradiation ionique. Les analyses correlees de la structure et de la magnetoresistance nous permettront d'emettre des conclusions sur l'influence des couches tampons entre l'interface et le substrat ainsi qu'entre les couches elles-memes sur le comportement magnetique des couches F/F. La troisieme partie est consacree aux systemes a Magneto-Resistance Geante (MRG) a base de Co et Ag. Nous allons etudier l'evolution de la microstructure suite a l'irradiation avec des ions Si+ ayant une energie de 1 MeV, ainsi que les effets de ces changements sur le comportement magnetique. Cette partie debutera par l'analyse des proprietes d'une multicouche hybride, intermediaire entre les multicouches et les materiaux granulaires. Nous analyserons a l'aide des mesures de diffraction, de relaxation superparamagnetique et de magnetoresistance, les evolutions structurales produites par l'irradiation ionique. Nous etablirons des modeles qui nous aideront a interpreter les resultats pour une serie des multicouches qui couvrent un large eventail de differents comportements magnetiques

  8. Steam generator tube failures

    SciTech Connect

    MacDonald, P.E.; Shah, V.N.; Ward, L.W.; Ellison, P.G.

    1996-04-01

    A review and summary of the available information on steam generator tubing failures and the impact of these failures on plant safety is presented. The following topics are covered: pressurized water reactor (PWR), Canadian deuterium uranium (CANDU) reactor, and Russian water moderated, water cooled energy reactor (VVER) steam generator degradation, PWR steam generator tube ruptures, the thermal-hydraulic response of a PWR plant with a faulted steam generator, the risk significance of steam generator tube rupture accidents, tubing inspection requirements and fitness-for-service criteria in various countries, and defect detection reliability and sizing accuracy. A significant number of steam generator tubes are defective and are removed from service or repaired each year. This wide spread damage has been caused by many diverse degradation mechanisms, some of which are difficult to detect and predict. In addition, spontaneous tube ruptures have occurred at the rate of about one every 2 years over the last 20 years, and incipient tube ruptures (tube failures usually identified with leak detection monitors just before rupture) have been occurring at the rate of about one per year. These ruptures have caused complex plant transients which have not always been easy for the reactor operators to control. Our analysis shows that if more than 15 tubes rupture during a main steam line break, the system response could lead to core melting. Although spontaneous and induced steam generator tube ruptures are small contributors to the total core damage frequency calculated in probabilistic risk assessments, they are risk significant because the radionuclides are likely to bypass the reactor containment building. The frequency of steam generator tube ruptures can be significantly reduced through appropriate and timely inspections and repairs or removal from service.

  9. Lunar Base Life Support Failures

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2009-01-01

    Dynamic simulation of the lunar outpost habitat life support was undertaken to investigate the impact of life support failures and to investigate responses. Some preparatory static analysis for the Lunar Outpost life support model, an earlier version of the model, and an investigation into the impact of Extravehicular Activity (EVA) were reported previously. (Jones, 2008-01-2184, 2008-01-2017) The earlier model was modified to include possible resupply delays, power failures, recycling system failures, and atmosphere and other material storage failures. Most failures impact the lunar outpost water balance and can be mitigated by reducing water usage. Food solids, nitrogen can be obtained only by resupply from Earth. The most time urgent failure is a lass of carbon dioxide removal capability. Life support failures might be survivable if effective operational solutions are provided in the system design.

  10. Intelligent failure-tolerant control

    NASA Technical Reports Server (NTRS)

    Stengel, Robert F.

    1991-01-01

    An overview of failure-tolerant control is presented, beginning with robust control, progressing through parallel and analytical redundancy, and ending with rule-based systems and artificial neural networks. By design or implementation, failure-tolerant control systems are 'intelligent' systems. All failure-tolerant systems require some degrees of robustness to protect against catastrophic failure; failure tolerance often can be improved by adaptivity in decision-making and control, as well as by redundancy in measurement and actuation. Reliability, maintainability, and survivability can be enhanced by failure tolerance, although each objective poses different goals for control system design. Artificial intelligence concepts are helpful for integrating and codifying failure-tolerant control systems, not as alternatives but as adjuncts to conventional design methods.

  11. Acute Liver Failure.

    PubMed

    Newland, Catherine D

    2016-12-01

    Pediatric acute liver failure (ALF) is a complex and rapidly progressive syndrome that results from a variety of age-dependent etiologies. It is defined by the acute onset of liver disease with no evidence of chronic liver disease. There must be biochemical or clinical evidence of severe liver dysfunction as defined by an international normalized ratio (INR) ≥2. If hepatic encephalopathy is present, INR should be ≥1.5. Unfortunately, due to the rarity of ALF in pediatric patients, there is a paucity of diagnostic and management algorithms and each patient must have an individualized approach. [Pediatr Ann. 2016;45(12):e433-e438.]. Copyright 2016, SLACK Incorporated.

  12. Renal Failure in Pregnancy.

    PubMed

    Balofsky, Ari; Fedarau, Maksim

    2016-01-01

    Renal failure during pregnancy affects both mother and fetus, and may be related to preexisting disease or develop secondary to diseases of pregnancy. Causes include hypovolemia, sepsis, shock, preeclampsia, thrombotic microangiopathies, and renal obstruction. Treatment focuses on supportive measures, while pharmacologic treatment is viewed as second-line therapy, and is more useful in mitigating harmful effects than treating the underlying cause. When supportive measures and pharmacotherapy prove inadequate, dialysis may be required, with the goal being to prolong pregnancy until delivery is feasible. Outcomes and recommendations depend primarily on the underlying cause.

  13. Pharmacoepigenetics in Heart Failure

    PubMed Central

    Mateo Leach, Irene; van der Harst, Pim

    2010-01-01

    Epigenetics studies inheritable changes of genes and gene expression that do not concern DNA nucleotide variation. Such modifications include DNA methylation, several forms of histone modification, and microRNAs. From recent studies, we know not only that genetic changes account for heritable phenotypic variation, but that epigenetic changes also play an important role in the variation of predisposition to disease and to drug response. In this review, we discuss recent evidence of epigenetic changes that play an important role in the development of cardiac hypertrophy and heart failure and may dictate response to therapy. PMID:20424992

  14. Gottfried Kirch (1639-1710) and astronomy in Berlin in the 18th century. Contributions of the colloquium held in Berlin-Treptow on March 6, 2010 (German Title: Gottfried Kirch (1639-1710) und die Berliner Astronomie im 18. Jahrhundert.) Beiträge des Kolloquiums am 6. März 2010 in Berlin-Treptow

    NASA Astrophysics Data System (ADS)

    Hamel, Jürgen

    2010-12-01

    The contributions of this volume are dedicated to Gottfried Kirch (1639-1710), the first Berlin astronomer, on the occasion of the 300th anniversary of his death. They deal with the astronomy of his times and developments in later times, which are connected to his work. The papers deal with the following topics: The instrumental equipment of Berlin Observatory at the time of G. Kirch and its modernisation up to around 1780; the instruments of Johann Makob Marioni's Viennese observatory around 1730; the heraldic celestial globe by Kirch's teacher Erhard Weigel. In addition, they deal with Kirch's share in the propagation of ideas of the Enlightenment, and with the Berlin meteorological record and its consequences for the investigation of anthropogenous climatic changes. They also deal with astronomical topics in the exchange of letters between Leonhard Euler and Daniel Bernoulli, and with the Berlin "Astronomisches Jahrbuch", which is based on Kirch's activities, as a biographical source.

  15. Why young elite athletes fear failure: consequences of failure.

    PubMed

    Sagar, Sam S; Lavallee, David; Spray, Christopher M

    2007-09-01

    Fear of failure can have negative effects on children in achievement settings, affecting many aspects of their lives. Perceiving the consequences of failure to be aversive provides the basis for fear of failure, and the anticipation of a threatening outcome elicits fear. Problems attributed to fear of failure in achievement settings are prevalent. Sport is a popular and significant achievement domain for children and adolescents and there is a lack of research on fear of failure in sport among this age group. Therefore, the aim of the present study was to investigate fear of failure in the sport domain among young elite athletes, and to explore their perceptions of the consequences of failure. Interviews were conducted individually with nine athletes aged 14 - 17 years (5 males, 4 females). Analysis identified and organized perceived consequences of failure into themes and categories. Results revealed that the most commonly perceived aversive consequences of failure were diminished perception of self, no sense of achievement, and the emotional cost of failure. These findings are consistent with those reported in adult population, suggesting the potential for generalizing existing results to young elite athletes.

  16. X-framework: Space system failure analysis framework

    NASA Astrophysics Data System (ADS)

    Newman, John Steven

    failures, and generating better and more consistent reports. Through this approach failures can be more fully understood, existing programs can be evaluated and future failures avoided. The x-fw development involved a review of the historical failure analysis and prevention literature, coupled with examination of numerous failure case studies. Analytical approaches included use of a relational failure "knowledge base" for classification and sorting of x-fw elements and attributes for each case. In addition a novel "management mapping" technique was developed as a means of displaying an integrated snapshot of indirect causes within the management chain. Further research opportunities will extend the depth of knowledge available for many of the component level cases. In addition, the x-fw has the potential to expand the scope of space sector lessons learned, and contribute to knowledge management and organizational learning.

  17. Elaboration de nouvelles approches micromecaniques pour l'optimisation des performances mecaniques des materiaux heterogenes

    NASA Astrophysics Data System (ADS)

    Aboutajeddine, Ahmed

    Les modeles micromecaniques de transition d'echelles qui permettent de determiner les proprietes effectives des materiaux heterogenes a partir de la microstructure sont consideres dans ce travail. L'objectif est la prise en compte de la presence d'une interphase entre la matrice et le renforcement dans les modeles micromecaniques classiques, de meme que la reconsideration des approximations de base de ces modeles, afin de traiter les materiaux multiphasiques. Un nouveau modele micromecanique est alors propose pour tenir compte de la presence d'une interphase elastique mince lors de la determination des proprietes effectives. Ce modele a ete construit grace a l'apport de l'equation integrale, des operateurs interfaciaux de Hill et de la methode de Mori-Tanaka. Les expressions obtenues pour les modules globaux et les champs dans l'enrobage sont de nature analytique. L'approximation de base de ce modele est amelioree par la suite dans un nouveau modele qui s'interesse aux inclusions enrobees avec un enrobage mince ou epais. La resolution utilisee s'appuie sur une double homogeneisation realisee au niveau de l'inclusion enrobee et du materiau. Cette nouvelle demarche, permettra d'apprehender completement les implications des approximations de la modelisation. Les resultats obtenus sont exploites par la suite dans la solution de l'assemblage de Hashin. Ainsi, plusieurs modeles micromecaniques classiques d'origines differentes se voient unifier et rattacher, dans ce travail, a la representation geometrique de Hashin. En plus de pouvoir apprecier completement la pertinence de l'approximation de chaque modele dans cette vision unique, l'extension correcte de ces modeles aux materiaux multiphasiques est rendue possible. Plusieurs modeles analytiques et explicites sont alors proposee suivant des solutions de differents ordres de l'assemblage de Hashin. L'un des modeles explicite apparait comme une correction directe du modele de Mori-Tanaka, dans les cas ou celui ci echoue a

  18. Adaptive control of nonlinear systems with actuator failures and uncertainties

    NASA Astrophysics Data System (ADS)

    Tang, Xidong

    2005-11-01

    Actuator failures have damaging effect on the performance of control systems, leading to undesired system behavior or even instability. Actuator failures are unknown in terms of failure time instants, failure patterns, and failure parameters. For system safety and reliability, the compensation of actuator failures is of both theoretical and practical significance. This dissertation is to further the study of adaptive designs for actuator failure compensation to nonlinear systems. In this dissertation a theoretical framework for adaptive control of nonlinear systems with actuator failures and system uncertainties is established. The contributions are the development of new adaptive nonlinear control schemes to handle unknown actuator failures for convergent tracking performance, the specification of conditions as a guideline for applications and system designs, and the extension of the adaptive nonlinear control theory. In the dissertation, adaptive actuator failure compensation is studied for several classes of nonlinear systems. In particular, adaptive state feedback schemes are developed for feedback linearizable systems and parametric strict-feedback systems. Adaptive output feedback schemes are deigned for output-feedback systems and a class of systems with unknown state-dependent nonlinearities. Furthermore, adaptive designs are addressed for MIMO systems with actuator failures, based on two grouping techniques: fixed grouping and virtual grouping. Theoretical issues such as controller structures, actuation schemes, zero dynamics, observation, grouping conditions, closed-loop stability, and tracking performance are extensively investigated. For each scheme, design conditions are clarified, and detailed stability and performance analysis is presented. A variety of applications including a wing-rock model, twin otter aircraft, hypersonic aircraft, and cooperative multiple manipulators are addressed with simulation results showing the effectiveness of the

  19. Etude des phenomenes de penetration des especes chimiques dans les revetements cathodiques des cuves d'electrolyse de l'aluminium

    NASA Astrophysics Data System (ADS)

    Brisson, Pierre-Yves

    Cette these decrit l'etude effectuee sur les phenomenes d'insertion du sodium et de penetration du bain electrolytique dans les revetements cathodiques des cuves d'electrolyse de l'aluminium. L'etude fut effectuee a l'aide d'un montage permettant d'effectuer l'electrolyse en laboratoire. Trois types de revetement cathodiques furent etudies : des blocs semi-graphitique, des blocs graphitiques et des blocs graphitises. L'insertion du sodium dans les trois differents types de blocs fut etudiee a l'aide de la spectrometrie des photoelectrons X (XPS). L'analyse a permis de mettre en evidence deux formes de sodium dans l'anthracite et la phase liante des materiaux semi-graphitiques et graphitiques, indiquant qu'une fraction du sodium se retrouve sous forme adsorbee dans les micropores des materiaux alors que l'autre fraction est inseree dans la structure cristalline du carbone. Dans les phases graphitiques (materiaux graphitises et graphitiques), seuls les micropores sont occupes par le sodium Ce resultat explique la tendance observee selon laquelle l'ajout de graphite dans les blocs permet d'abaisser le gonflement sodique. Les mecanismes de penetration du bain dans le reseau poreux des materiaux furent etudies en microscopie electronique et en diffraction des rayons X sur des echantillons apres differents temps d'electrolyses et en variant l'atmosphere (soit sous argon ou sous azote). Ces analyses ont permis d'identifier le mecanisme conduisant a la mouillabilite du bain sur le carbone en fonction de l'atmosphere entourant l'electrolyse. Ainsi, sous azote, la formation de NaCN dans les pores des materiaux par reactions entre le sodium et l'azote permet une mouillabilite accrue du bain alors qu'en absence d'azote (sous argon), le carbure d'aluminium, formes a la surface des pores, joue un role similaire. Dans ce dernier cas, la penetration du bain est moins rapide etant donnee la necessite de toujours amener des especes contenant de l'aluminium en tete du front de

  20. Scaling of structural failure

    SciTech Connect

    Bazant, Z.P.; Chen, Er-Ping

    1997-01-01

    This article attempts to review the progress achieved in the understanding of scaling and size effect in the failure of structures. Particular emphasis is placed on quasibrittle materials for which the size effect is complicated. Attention is focused on three main types of size effects, namely the statistical size effect due to randomness of strength, the energy release size effect, and the possible size effect due to fractality of fracture or microcracks. Definitive conclusions on the applicability of these theories are drawn. Subsequently, the article discusses the application of the known size effect law for the measurement of material fracture properties, and the modeling of the size effect by the cohesive crack model, nonlocal finite element models and discrete element models. Extensions to compression failure and to the rate-dependent material behavior are also outlined. The damage constitutive law needed for describing a microcracked material in the fracture process zone is discussed. Various applications to quasibrittle materials, including concrete, sea ice, fiber composites, rocks and ceramics are presented.

  1. Heart Failure Readmission Reduction.

    PubMed

    Drozda, Joseph P; Smith, Donna A; Freiman, Paul C; Pursley, Janet; VanSlette, Jeffrey A; Smith, Timothy R

    Little is known regarding effectiveness of readmission reduction programs over time. The Heart Failure Management Program (HFMP) of St. John's Physician Group Practice (PGP) Demonstration provided an opportunity to assess outcomes over an extended period. Data from an electronic health record, an inpatient database, a disease registry, and the Social Security Death Master File were analyzed for patients admitted with heart failure (HF) for 5 years before (Period 1) and 5 years after (Period 2) inception of PGP. HF admissions decreased (Period 1, 58.3/month; Period 2, 52.4/month, P = .007). Thirty-day all-cause readmission rate dropped from Period 1 (annual average 18.8% [668/3545]) to year 1 of Period 2 (16.9% [136/804], P = .04) and remained stable thereafter (annual average 16.8% [589/3503]). Thirty-day mortality rate was flat throughout. HFMP was associated with decreased readmissions, primarily related to outpatient case management, while mortality remained stable.

  2. Preparing for Failure

    SciTech Connect

    Murphy, L.T.

    2006-07-01

    Risk management is one of the most complex project management processes, requiring rigorous management and discipline. Unfortunately, for many organizations, the risk management process has become contaminated by poor management practices, an absence of meaningful risk assessments, meaningless risk event descriptions, incomplete and vague risk impact analyses, poor follow through on risk mitigation activities and a general lack of attention to accuracy, completeness and quality. At this point, the risk register, instead of being a key tool used by the organization to systematically identify and eliminate risk, while exploiting opportunities, has become a list of pre-prepared excuses based on the repeat of failures encountered on past projects. However, organizations are not condemned to repeat past failures. By returning to the basics of risk management, and through the application of some basic management guidelines, the risk register-instead of being an 'Excuse Register' - can become the cornerstone of a comprehensive risk management program to promote a systematic, pro-active approach within an organization that will result in accomplishing mitigation activities, reducing risk and gaining advantage through opportunities. (authors)

  3. Fracture, failure, and fragmentation

    NASA Technical Reports Server (NTRS)

    Dienes, J. K.

    1984-01-01

    A general approach is required for describing matter of behavior when the failure is likely to involve growth and coalescence of a large number of fractures. Failures of this kind appear frequently in rapid dynamic processes, particularly in the formation of spall fragments. An approach to formulating constitutive relations that accounts for the opening, shear and growth of an ensemble of cracks is discussed. The approach accounts for plastic flow accompanying fragmentation. The resulting constitutive relations were incorporated into a Lagrangian computer program. A theoretical approach to coalescence is described. The simplest formulation uses a linear Liouville equation, with crack growth limited by the mean free path of cracks, assumed constant. This approach allows for an anisotropic distribution of cracks. An alternative approach in which the decrease of the mean free path with increasing crack size is accounted for, but the crack distribution is assumed isotropic is described. A reduction of the governing Liouville equation to an ordinary differential equation of third order is possible, and the result can be used to determine how mean free path decreases with increasing crack size.

  4. Energetics of lithium ion battery failure.

    PubMed

    Lyon, Richard E; Walters, Richard N

    2016-11-15

    The energy released by failure of rechargeable 18-mm diameter by 65-mm long cylindrical (18650) lithium ion cells/batteries was measured in a bomb calorimeter for 4 different commercial cathode chemistries over the full range of charge using a method developed for this purpose. Thermal runaway was induced by electrical resistance (Joule) heating of the cell in the nitrogen-filled pressure vessel (bomb) to preclude combustion. The total energy released by cell failure, ΔHf, was assumed to be comprised of the stored electrical energy E (cell potential×charge) and the chemical energy of mixing, reaction and thermal decomposition of the cell components, ΔUrxn. The contribution of E and ΔUrxn to ΔHf was determined and the mass of volatile, combustible thermal decomposition products was measured in an effort to characterize the fire safety hazard of rechargeable lithium ion cells.

  5. Modeling of microstructural effects on electromigration failure

    SciTech Connect

    Ceric, H.; Orio, R. L. de; Zisser, W.; Selberherr, S.

    2014-06-19

    Current electromigration models used for simulation and analysis of interconnect reliability lack the appropriate description of metal microstructure and consequently have a very limited predictive capability. Therefore, the main objective of our work was obtaining more sophisticated electromigration tools. The problem is addressed through a combination of different levels of atomistic modeling and already available, continuum level macroscopic models. A novel method for an ab initio calculation of the effective valence for electromigration is presented and its application on the analysis of EM behavior is demonstrated. Additionally, a simple analytical model for the early electromigration lifetime is obtained. We have shown that its application provides a reasonable estimate for the early electromigration failures including the effect of microstructure. A simulation study is also applied on electromigration failure in tin solder bumps, where it contributed the understanding of the role of tin crystal anisotropy in the degradation mechanism of solder bumps.

  6. Cardiac Imaging in Heart Failure with Comorbidities.

    PubMed

    Wong, Chiew; Chen, Sylvia; Iyngkaran, Pupalan

    2017-01-01

    Imaging modalities stand at the frontiers for progress in congestive heart failure (CHF) screening, risk stratification and monitoring. Advancements in echocardiography (ECHO) and Magnetic Resonance Imaging (MRI) have allowed for improved tissue characterizations, cardiac motion analysis, and cardiac performance analysis under stress. Common cardiac comorbidities such as hypertension, metabolic syndromes and chronic renal failure contribute to cardiac remodeling, sharing similar pathophysiological mechanisms starting with interstitial changes, structural changes and finally clinical CHF. These imaging techniques can potentially detect changes earlier. Such information could have clinical benefits for screening, planning preventive therapies and risk stratifying patients. Imaging reports have often focused on traditional measures without factoring these novel parameters. This review is aimed at providing a synopsis on how we can use this information to assess and monitor improvements for CHF with comorbidities.

  7. TRANSPLANTATION EN MASSE DES ORGANES ABDOMINAUX

    PubMed Central

    STARZL, T.

    2010-01-01

    Les transplantations multi-organes, comprenant les blocs foie-duodénum-pancréas, foie-estomac-duodénum-pancréas, et foie-intestin sont réalisées avec un succés croissant Ces techniques et leurs combinaisons variées de transplantation monobloc ne sont pas de pratique courante. Les techniques de prélévement, de conservation et de soins post-opératoires sont décrites pour la transplantation multi-organes compléte ainsi que pour les variantes incomplétes. Le probléme particulier à ce type de transplantation est celui de la transplantation intestinale, c’est-à-dire la transplantation d’un organe à composante lymphoréticulaire complexe ce qui peut provoquer un syndrome greffon contre hôte. Par erreur de conception, et un peu par esprit de systéme, les efforts par le passé étaient dirigés sur la modification et la destruction des systémes lymphoréticulaires grâce au traitement préalable du donneur ou des organes transplantés, par médicaments, radiation ou autres moyens. Actuellement, I’idée directrice est de garder intacte les systémes lymphoréticulaires qui deviennent alors le site d’une circulation à double sens aprés transplantation. Avec la puissante immunodépression que fournit le FK 506, les cellules lymphoréticulaires du donneur peuvent circuler chez le receveur sans créer de syndrome du greffon contre hôte clinique et les cellules de la greffe s’assimilent à celles du receveur (chimérisme local) sans provoquer de rejet. Même si I’on évite le rejet ou le syndrome greffon contre hôte, il existe, à côté de ces entités, des relations métaboliques entre les organes greffés ainsi qu’entre les organes greffés et les viscéres du receveur laissés en place, qui peuvent influencer I’avenir soit des organes greffés, soit des organes laissés en place. Parmi les échanges métaboliques les mieux connus actuellement, il y a les facteurs splanchniques hépatotrophes endogénes, dont I’insuline est la mieux

  8. Insomnia Self-Management in Heart Failure

    ClinicalTrials.gov

    2016-12-07

    Cardiac Failure; Heart Failure; Congestive Heart Failure; Heart Failure, Congestive; Sleep Initiation and Maintenance Disorders; Chronic Insomnia; Disorders of Initiating and Maintaining Sleep; Fatigue; Pain; Depressive Symptoms; Sleep Disorders; Anxiety

  9. Peste des petits ruminants in Arabian wildlife.

    PubMed

    Kinne, J; Kreutzer, R; Kreutzer, M; Wernery, U; Wohlsein, P

    2010-08-01

    Recurrence of peste des petits ruminants (PPR) was diagnosed in the United Arabian Emirates in several wild ruminants confirmed by morphological, immunohistochemical, serological and molecular findings. Phylogenetic analysis revealed that the virus strain belongs to lineage IV, which is different to some previously isolated PPR strains from the Arabian Peninsula. This study shows that wild ruminants may play an important epidemiological role as virus source for domestic small ruminants.

  10. Regulation of renal glomerular and papillary ANP receptors in rats with experimental heart failure.

    PubMed

    Yechieli, H; Kahana, L; Haramati, A; Hoffman, A; Winaver, J

    1993-07-01

    Rats with aortocaval (A-V) fistula, an experimental model of congestive heart failure (CHF), display high circulating atrial natriuretic peptide (ANP) levels and a markedly blunted natriuretic response to ANP infusion. The present study was designed to evaluate whether alterations in renal ANP receptors may contribute to renal hyporesponsiveness to ANP in experimental CHF. Densities (Bmax) and dissociation constants (Kd) of both the biologically active (ANPA) and clearance receptors (ANPC) were evaluated in glomerular and papillary membranes from A-V fistula rats (n = 18) and sham-operated controls (n = 20). ANPA and ANPC receptor subtypes were assayed by displacement of 125I-ANP-(99-126) bound to glomerular or papillary membranes by increasing concentrations of unlabeled ANP-(99-126) or des-(18-22)-ANP-(4-23), an analogue which binds only to ANPC. Seven days after the operation, rats with A-V fistula displayed avid sodium retention, elevated plasma renin activity, and approximately a 10-fold increase in plasma ANP levels. Bmax of total ANP binding sites was significantly decreased in rats with A-V fistula compared with controls (220 +/- 61 vs. 399 +/- 88 fmol/mg protein, P < 0.05). The decrease was mainly due to a reduction in ANPA receptor density (51 +/- 10 vs. 110 +/- 15 fmol/mg protein, P < 0.05) with no change in receptor affinity. Likewise, a significant reduction in the density of ANPA (23 +/- 5 vs. 64 +/- 10 fmol/mg protein, P < 0.05) with no change in receptor affinity was observed in papillary membranes of rats with A-V fistula.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Remote monitoring of heart failure patients.

    PubMed

    Bhimaraj, Arvind

    2013-01-01

    "The Teledactyl (Tele, far; Dactyl, finger--from the Greek) is a future instrument by which it will be possible for us to 'feel at a distance.' This idea is not at all impossible, for the instrument can be built today with means available right now. It is simply the well known telautograph, translated into radio terms, with additional refinements. The doctor of the future, by means of this instrument, will be able to feel his patient, as it were, at a distance...The doctor manipulates his controls, which are then manipulated at the patient's room in exactly the same manner. The doctor sees what is going on in the patient's room by means of a television screen." -Hugo Gernsback, Science and Invention Magazine, February 1925 Heart failure continues to be a major burden on our health care system. As the number of patients with heart failure increases, the cost of hospitalization alone is contributing significantly to the overall cost of this disease. Readmission rate and hospital length of stay are emerging as quality markers of heart failure care along with reimbursement policies that force hospitals to optimize these outcomes. Apart from maintaining quality assurance, the disease process of heart failure per-se requires demanding and close attention to vitals, diet, and medication compliance to prevent acute decompensation episodes. Remote patient monitoring is morphing into a key disease management strategy to optimize care for heart failure. Innovative implantable technologies to monitor intracardiac hemodynamics also are evolving, which potentially could offer better and substantial parameters to monitor.

  12. Remote Monitoring of Heart Failure Patients

    PubMed Central

    Bhimaraj, Arvind

    2013-01-01

    “The Teledactyl (Tele, far; Dactyl, finger — from the Greek) is a future instrument by which it will be possible for us to ‘feel at a distance.’ This idea is not at all impossible, for the instrument can be built today with means available right now. It is simply the well known telautograph, translated into radio terms, with additional refinements. The doctor of the future, by means of this instrument, will be able to feel his patient, as it were, at a distance…The doctor manipulates his controls, which are then manipulated at the patient’s room in exactly the same manner. The doctor sees what is going on in the patient’s room by means of a television screen.” —Hugo Gernsback, Science and Invention Magazine, February 1925 Heart failure continues to be a major burden on our health care system. As the number of patients with heart failure increases, the cost of hospitalization alone is contributing significantly to the overall cost of this disease. Readmission rate and hospital length of stay are emerging as quality markers of heart failure care along with reimbursement policies that force hospitals to optimize these outcomes. Apart from maintaining quality assurance, the disease process of heart failure per-se requires demanding and close attention to vitals, diet, and medication compliance to prevent acute decompensation episodes. Remote patient monitoring is morphing into a key disease management strategy to optimize care for heart failure. Innovative implantable technologies to monitor intracardiac hemodynamics also are evolving, which potentially could offer better and substantial parameters to monitor. PMID:23519115

  13. Sonderverfahren des Spritzgießens

    NASA Astrophysics Data System (ADS)

    Michaeli, Walther; Lettowsky, Christoph

    Das Spritzgießen ist neben der Extrusion das wichtigste Verarbeitungsverfahren für Kunststoffe [1]. Das Verfahren hat sich seit seinen Ursprüngen Ende des 19. Jahrhunderts bis heute stetig weiterentwickelt [2]. In neuerer Zeit steigt die Anzahl komplexer Anwendungen, die die gezielte Kombination verschiedener Funktionalitäten in einem Formteil erfordern. Das Standard-Spritzgießen kann diese Anforderungen immer weniger befriedigen. Daher gewinnen die Sonderverfahren des Spritzgießens zunehmend an Bedeutung [3]. Ihre Anzahl beträgt inzwischen über 100. Die Aufgabe des Anwenders ist es, aus der Vielzahl der möglichen Verfahren, ein anforderungsgerechtes auszuwählen, das sowohl unter technischen wie wirtschaftlichen Gesichtspunkten die optimale Lösung darstellt. Dies setzt die ständige Auseinandersetzung mit Entwicklungstendenzen im Bereich der Spritzgießtechnologie voraus. Daher soll im folgenden Abschnitt ein Überblick über die wichtigsten Spritzgieß-Sonderverfahren gegeben werden.

  14. Newtons Universum. Materialien zur Geschichte des Kraftbegriffes.

    NASA Astrophysics Data System (ADS)

    Mit einem Vorwort von E. Seibold und einer Einführung von W. Neuser. This book is a selection of 15 articles published in the journal "Spektrum der Wissenschaft". The original English versions of the papers were first published in "Scientific American". Contents: 1. Impetustheorie und Intuition in der Physik (M. McCloskey). 2. Mittelalterliche Ursprünge der industriellen Revolution (T. S. Reynolds). 3. Leonardo da Vincis Beiträge zur theoretischen Mechanik (V. Foley, W. Soedel). 4. Nikolaus Kopernikus und Tycho Brahe (O. Gingerich). 5. Keplers Entdeckung der ersten beiden Planetengesetze (C. Wilson). 6. Galileis Entdeckung des Fallgesetzes (S. Drake). 7. Galileis Beobachtung des Neptun (S. Drake, C. T. Kowal). 8. Galileo Galilei und der Schatten des Giordano Bruno (L. S. Lerner, E. A. Gosselin). 9. Der Fall Galilei (O. Gingerich). 10. Newtons Apfel und Galileis "Dialog" (S. Drake). 11. Newtons Gravitationsgesetz - aus Formeln wird eine Idee (I. B. Cohen). 12. Christopher Wren: Astronom und Architekt (H. Dorn, R. Mark). 13. Atomismus und Kräfte in der Geschichte (L. Holliday). 14. Ein Elitezirkel vor 200 Jahren: Die Lunar Society von Birmingham (L. Ritchie-Calder). 15. Sadi Carnot: Technik und Theorie der Dampfmaschine (S. S. Wilson).

  15. Dermatomyosite et panniculite: place des immunoglobulines

    PubMed Central

    Abdelhafidh, Nadia Ben; Toujeni, Sana; Kefi, Asma; Bousetta, Najeh; Sayhi, Sameh; Gharsallah, Imen; Othmani, Salah

    2016-01-01

    La panniculite est une maladie inflammatoire du tissu adipeux sous-cutané rarement associée à la dermatomyosite. Elle peut survenir avant, après ou en même temps que l'atteinte musculaire. Dans la plupart des cas, l’évolution de la panniculite et des autres atteintes de la dermatomyosite est favorable sous traitement corticoïde et/ou immunosuppresseur. Nous rapportons le cas d'une patiente âgée de 48 ans ayant présenté des lésions de panniculite précédant de 2 mois les signes musculaires. L'atteinte cutanée était résistante au traitement corticoïde associés aux immunosuppresseurs ce qui a nécessité le recours au traitement par Immunoglobulines polyvalentes permettant ainsi une amélioration à la fois de l'atteinte cutanée et musculaire. PMID:27516827

  16. [Settlement effected for damages for victims of diethylstilbestrol (DES)].

    PubMed

    van Erp, E J M; Heintz, A P M; Helmerhorst, T J M; Koster, M E T A; van Leeuwen, F E

    2007-05-26

    In 2007 the Dutch DESFonds (DES Fund) starts payment to victims of exposure to diethylstilbestrol in a collective settlement. This is unique in the world because the arrangement covers the entire range of DES-related disorders and individual persons do not have to start an expensive and emotionally taxing legal procedure with uncertain outcome, which would last several years. Individuals can now be compensated based on medical evidence of DES exposure and the presence of a DES-related disorder covered by the settlement. In close collaboration with the DES Centre (an association of DES victims) a careful procedure was followed before this settlement was realised. The Dutch Expert Committee on DES-related Health Effects first reviewed the literature for evidence and established a list of disorders with a causal association with DES. For each DES-related disorder covered by the settlement, the appropriate compensation was determined by the attributive risk and the severity of the disease. The settlement is the result of close collaboration between all parties involved.

  17. Combustion of Solid Propellants (La Combustion des Propergols Solides)

    DTIC Science & Technology

    1991-07-01

    on peut s’interroger sur l’adquation des moyens engages ausceptiblea do se manifester naturellement au cours du A Ia complexit6 du probl~me... capteur d’Helmoltz; de pression lorsque Ia fr~quence vanet. Calcul num~rique et mithode expdrimentale donnent des irdsultats en bon accord, c’cst-i... naturellement , avec des niveaux stabilis~s moddr~s. mod~le de combustion (r~f. 30) et des limites de L’opinion est r~pandue que la segmentation peut l’approche

  18. Inhomogeneites dans le Vent des Etoiles Wolf-Rayet

    NASA Astrophysics Data System (ADS)

    Robert, Carmelle

    1992-01-01

    Des mesures spectroscopiques effectuees avec un haut rapport signal sur bruit et une bonne resolution ont demontre l'existence de regions perturbees en mouvement dans le vent d'etoiles Wolf-Rayet (WR). L'echantillon d'objets etudies ici comprend 9 etoiles WR couvrant differents sous-types WN et WC. De nombreuses petites structures variables superposees au profil des raies d'emission formees dans le vent stellaire signalent la presence des perturbations. L'etude des variations globales des raies et l'examen des micro-structures individuelles ont permis de decrire plusieurs caracteristiques des perturbations. Entre autres, on observe des correlations significatives entre le niveau de variabilite des raies et certains parametres des etoiles qui confirment que le phenomene de variabilite est intrinseque au vent stellaire. En comparant les changements des vitesses radiales et des largeurs equivalentes des differentes raies d'une meme etoile, on conclut que les regions perturbees ont une etendue finie par rapport a l'enveloppe des etoiles. On peut facilement suivre les structures individuelles sur une periode de temps couvrant ~eq8 heures (et peut etre meme 24 heures) avant qu'elles ne disparaissent. Durant ce temps les structures se deplacent en s'eloignant du centre de la raie. A partir des differents comportements notes lors de l'analyse des variations globales et lors de l'examen des structures individuelles, on propose de representer les perturbations par un modele d'inhomogeneites discretes en expansion dans le vent. On suppose simplement que les inhomogeneites emettent comme le vent global (et absorbent aussi si le vent global montre un profil P Cyg). La superposition du graphique de l'acceleration radiale moyenne des inhomogeneites de WR140 en fonction de leur vitesse radiale et du modele theorique d'inhomogeneites qui suivent la loi generale de vitesse donne un taux d'acceleration lent, avec beta >= 3 pour les inhomogeneites de cette etoile. On obtient, entre

  19. Annual Program Management Report (1990), Des Moines Recreational River and Greenbelt, Des Moines River, Iowa

    DTIC Science & Technology

    1990-12-01

    study are listed below: STUDY MANAGEMENT C111 Jim MIll I SITE PLANNING George Gitter, AICP ECONOMIC AND SOCIAL ANALYSIS Patricia Risser ENVIRONMENTAL...Trail (Raccoon River Segment), Des Moines - The project involves the construction of approximately 42,500 feet of paved multi-purpose trail in the...Federd Fee kwe Sc Am 1000 02000 ~]Lod Area -~ aroraed SCALE FEET Des Moies Recreaond Rvf And Greenbdt U.S. ARMY VNGDIKE DITrWC - ROC BLAND -A MOCK SA’rL0A

  20. Etude des phenomenes dynamiques ultrarapides et des caracteristiques impulsionnelles d'emission terahertz du supraconducteur YBCO

    NASA Astrophysics Data System (ADS)

    Savard, Stephane

    Les premieres etudes d'antennes a base de supraconducteurs a haute temperature critique emettant une impulsion electromagnetique dont le contenu en frequence se situe dans le domaine terahertz remontent a 1996. Une antenne supraconductrice est formee d'un micro-pont d'une couche mince supraconductrice sur lequel un courant continu est applique. Un faisceau laser dans le visible est focalise sur le micro-pont et place le supraconducteur dans un etat hors-equilibre ou des paires sont brisees. Grace a la relaxation des quasiparticules en surplus et eventuellement de la reformation des paires supraconductrices, nous pouvons etudier la nature de la supraconductivite. L'analyse de la cinetique temporelle du champ electromagnetique emis par une telle antenne terahertz supraconductrice s'est averee utile pour decrire qualitativement les caracteristiques de celle-ci en fonction des parametres d'operation tels que le courant applique, la temperature et la puissance d'excitation. La comprehension de l'etat hors-equilibre est la cle pour comprendre le fonctionnement des antennes terahertz supraconductrices a haute temperature critique. Dans le but de comprendre ultimement cet etat hors-equilibre, nous avions besoin d'une methode et d'un modele pour extraire de facon plus systematique les proprietes intrinseques du materiau qui compose l'antenne terahertz a partir des caracteristiques d'emission de celle-ci. Nous avons developpe une procedure pour calibrer le spectrometre dans le domaine temporel en utilisant des antennes terahertz de GaAs bombarde aux protons H+ comme emetteur et detecteur. Une fois le montage calibre, nous y avons insere une antenne emettrice dipolaire de YBa 2Cu3O7-delta . Un modele avec des fonctions exponentielles de montee et de descente du signal est utilise pour lisser le spectre du champ electromagnetique de l'antenne de YBa 2Cu3O7-delta, ce qui nous permet d'extraire les proprietes intrinseques de ce dernier. Pour confirmer la validite du modele

  1. Global Failure Modes in Composite Structures

    NASA Technical Reports Server (NTRS)

    Knauss, W. G.; Gonzalez, Luis

    2001-01-01

    Composite materials provide well-known advantages for space and aeronautical applications in terms of strength and rigidity to weight ratios and other mechanical properties. As a consequence, their use has experienced a constant increase in the past decades and it is anticipated that this trend will be maintained in the near future. At the same time, being these materials relatively new compared to metals, and having failure characteristics completely different from them, their damage growth and their failure mechanisms are not as well understood in a predictive sense. For example, while in metals fracture produces "clean" cracks with their well defined analytically stress fields at the crack tip, composite fracture is a more complex phenomenon. Instead of a crack, we confront a "damage zone" that may include fiber breakage, fiber microbuckling, fiber pullout, matrix cracking, delamination, debonding or any combination of all these different mechanisms. These phenomena are prevalent in any failure process through an aircraft structure, whether one addresses a global failure such as the ripping of a fuselage or wing section, or whether one is concerned with the failure initiation near a thickness change at stringers or other reinforcement. Thus the topic that has been under consideration has wide application in any real structure and is considered an essential contribution to the predictive failure analysis capability for aircraft containing composite components. The heterogeneity and the anisotropy of composites are not only advantageous but essential characteristics, yet these same features provide complex stress fields, especially in the presence of geometrical discontinuities such as notches, holes or cutouts or structural elements such as stiffeners, stringers, etc. To properly address the interaction between a damage/crack front and a hole with a stringer it is imperative that the stress and deformation fields of the former be (sufficiently well) characterized

  2. Fatigue failure load indicator

    NASA Technical Reports Server (NTRS)

    Imig, L. A.; Davis, W. T.; Davis, D. C. (Inventor)

    1979-01-01

    An indicator for recording the load at which a fatigue specimen breaks during the last cycle of a fatigue test is described. A load cell is attached to the specimen which is alternately subjected to tension and compression loads. The output of the load cell which is proportional to the load on the specimen is applied to the input of a peak detector. Each time the specimen is subjected to a compression load, means are provided for applying a positive voltage to the rest of the peak detector to reset it. During the last cycle of the tension load the peak detector measures the maximum load on the specimen. Means are provided for disconnecting the load cell from the peak detector when there is a failure in the specimen.

  3. Component failure data handbook

    SciTech Connect

    Gentillon, C.D.

    1991-04-01

    This report presents generic component failure rates that are used in reliability and risk studies of commercial nuclear power plants. The rates are computed using plant-specific data from published probabilistic risk assessments supplemented by selected other sources. Each data source is described. For rates with four or more separate estimates among the sources, plots show the data that are combined. The method for combining data from different sources is presented. The resulting aggregated rates are listed with upper bounds that reflect the variability observed in each rate across the nuclear power plant industry. Thus, the rates are generic. Both per hour and per demand rates are included. They may be used for screening in risk assessments or for forming distributions to be updated with plant-specific data.

  4. Iridium: failures & successes

    NASA Astrophysics Data System (ADS)

    Christensen, CarissaBryce; Beard, Suzette

    2001-03-01

    This paper will provide an overview of the Iridium business venture in terms of the challenges faced, the successes achieved, and the causes of the ultimate failure of the venture — bankruptcy and system de-orbit. The paper will address technical, business, and policy issues. The intent of the paper is to provide a balanced and accurate overview of the Iridium experience, to aid future decision-making by policy makers, the business community, and technical experts. Key topics will include the history of the program, the objectives and decision-making of Motorola, the market research and analysis conducted, partnering strategies and their impact, consumer equipment availability, and technical issues — target performance, performance achieved, technical accomplishments, and expected and unexpected technical challenges. The paper will use as sources trade media and business articles on the Iridium program, technical papers and conference presentations, Wall Street analyst's reports, and, where possible, interviews with participants and close observers.

  5. Mud pump failure analysis

    SciTech Connect

    Lewis, E.C. II

    1981-10-01

    Extrusion, the primary cause of piston failure, is the degradation of a seal caused by the seal material moving into the interface between the two parts being sealed. It is shown that operational dynamics of the mud piston lead to an aggravated extrusion condition. As both the liner wall and the piston OD lose material, the clearance gap between liner and piston increases. This gap provides the piston seal a space to move into when pressurized. This movement, called extrusion, is undesirable because the piston rubber is then subjected to abnormal stresses which it cannot tolerate. As the piston moves forward, this extruded material is gradually nibbled away. Extrusion and nibble action continue on each stroke of the pump as additional rubber moves away from the high-pressure side of the piston toward the low-pressure side. A discussion is presented of extrusion rates and seal leakage.

  6. Vein graft failure

    PubMed Central

    Owens, Christopher D.; Gasper, Warren J.; Rahman, Amreen S.; Conte, Michael S

    2013-01-01

    Following the creation of an autogenous lower extremity bypass graft, the vein must undergo a series of dynamic structural changes to stabilize the arterial hemodynamic forces. These changes, commonly referred to as remodeling, include an inflammatory response, the development of a neointima, matrix turnover, and cellular proliferation and apoptosis. The sum total of these processes results in dramatic alterations in the physical and biomechanical attributes of the arterialized vein. The most clinically obvious and easily measured of these is lumen remodeling of the graft. However, though somewhat less precise, wall thickness, matrix composition, and endothelial changes can be measured in vivo within the healing vein graft. Recent translational work has demonstrated the clinical relevance of remodeling as it relates to vein graft patency and the systemic factors influencing it. By correlating histologic and molecular changes in the vein, insights into potential therapeutic strategies to prevent bypass failure and areas for future investigation are explored. PMID:24095042

  7. Les effets du travail en equipe dans l'apprentissage par projets sur la motivation des etudiantes et des etudiants en formation des ingenieurs

    NASA Astrophysics Data System (ADS)

    Fernandez, Nicolas

    Les representants des secteurs industriels et les, milieux professionnels en Amerique du Nord reprochaient aux universites de former des ingenieurs avec peu d'experience pratique en resolution de problemes et en conception. Quelques programmes de genie ont alors mis en place le travail en equipe dans l'apprentissage par projets. Beaucoup d'ecrits font valoir les benefices de l'apprentissage par projets sur la motivation des etudiants. Or, ces benefices commencent a peine a faire l'objet de recherches visant a produire des donnees probantes a ce sujet. Les travaux sur la motivation en contexte d'apprentissage et les modeles theoriques developpes sont issus d'environnements d'apprentissage marques par l'enseignement magistral. Le modele de la valeur attendue de la tache (Eccles et Wigfield, 1995; Neuville, 2004) et le modele du systeme-groupe (St-Arnaud, 2008) ont ete retenus pour mesurer les effets du travail en equipe dans l'apprentissage par projets sur la motivation. La recherche visait aussi a approfondir et a nuancer la comprehension de la motivation des etudiants universitaires apprenant en contexte innovant. Les sujets constituent des etudiants (n=100) travaillant sur des projets d'integration au cours des trois sessions initiales du programme de genie mecanique d'une universite canadienne. L'analyse de regression multiple revele que les construits de la motivation expliquent un tiers de la variance de l'engagement academique dans la realisation du projet d'integration. Les perceptions de l' "expectancy", de la valeur intrinseque et utilitaire sont les determinants principaux de l'engagement des etudiants. L'analyse de variance multivariee a mesures repetees indique que la motivation des etudiants pour le travail sur les projets d'integration a augmente au cours des trois sessions initiales du parcours de formation. Finalement, malgre l'absence d'interaction significative entre les variables de motivation et de l'equipe, les reponses des sujets indiquent une

  8. Transition de phase quantique de type verrouillage-deverrouillage dans les canaux lineaires coherents des phases en rayures dans les doubles puits quantiques sous champ magnetique perpendiculaire

    NASA Astrophysics Data System (ADS)

    Faribault, Alexandre

    On peut creer un gaz electronique bidimensionnel en utilisant le potentiel de confinement d'une couche mince d'un semiconducteur dans un substrat fait d'une autre semiconducteur de gap plus eleve. L'ajout d'un champ magnetique perpendiculaire au plan de confinement modifie de facon drastique les proprietes du gaz electronique. Pour des densites et des valeurs du champ magnetique adequatement choisies, on obtient un etat fondamental en onde de densite de charge. Dans un systeme compose de deux de ces gaz bidimensionnels suffisamment rapproches l'un de l'autre, on prevoit theoriquement l'existence d'un etat fondamental compose d'une onde de densite de charge dans chacun des puits et d'une serie de regions lineaires ou l'on a une delocalisation coherente des electrons entre les deux puits. Dans cette these, on etudie le comportement a temperature nulle de cet etat fondamental en rayures coherentes. L'etude numerique des modes collectifs de ces phases laisse croire qu'un deverrouillage des canaux coherents est envisageable dans ce systeme. Afin d'etudier cette possibilite, nous construisons d'abord un modele effectif de canaux quasi-unidimensionnels couples qui permettent de reproduire correctement les excitations collectives a basse energie de la phase en rayures coherentes du double puits quantique. Dans un systeme de coordonnees adequatement choisi, ces excitations peuvent etre decrites par des ondes de pseudospin. Les parametres de ce modele effectif simple peuvent etre extraits des calculs des fonctions de reponse realises dans l'approximation Hartree-Fock dependante du temps (appelee aussi Generalized Random Phase Approximation). On constate l'efficacite de ce modele a decrire la dynamique basse energie du systeme pour une certaine plage de distances inter-puits. En retirant de ce modele les contributions a l'hamiltonien provenant des couplages de type Josephson entre les canaux, on obtient alors un systeme ou les canaux sont deverrouilles. Un traitement en

  9. Metabolic mechanisms in heart failure.

    PubMed

    Ashrafian, Houman; Frenneaux, Michael P; Opie, Lionel H

    2007-07-24

    Although neurohumoral antagonism has successfully reduced heart failure morbidity and mortality, the residual disability and death rate remains unacceptably high. Though abnormalities of myocardial metabolism are associated with heart failure, recent data suggest that heart failure may itself promote metabolic changes such as insulin resistance, in part through neurohumoral activation. A detrimental self-perpetuating cycle (heart failure --> altered metabolism --> heart failure) that promotes the progression of heart failure may thus be postulated. Accordingly, we review the cellular mechanisms and pathophysiology of altered metabolism and insulin resistance in heart failure. It is hypothesized that the ensuing detrimental myocardial energetic perturbations result from neurohumoral activation, increased adverse free fatty acid metabolism, decreased protective glucose metabolism, and in some cases insulin resistance. The result is depletion of myocardial ATP, phosphocreatine, and creatine kinase with decreased efficiency of mechanical work. On the basis of the mechanisms outlined, appropriate therapies to mitigate aberrant metabolism include intense neurohumoral antagonism, limitation of diuretics, correction of hypokalemia, exercise, and diet. We also discuss more novel mechanistic-based therapies to ameliorate metabolism and insulin resistance in heart failure. For example, metabolic modulators may optimize myocardial substrate utilization to improve cardiac function and exercise performance beyond standard care. The ultimate success of metabolic-based therapy will be manifest by its capacity further to lessen the residual mortality in heart failure.

  10. Insulation failure in laparoscopic instruments.

    PubMed

    Montero, Paul N; Robinson, Thomas N; Weaver, John S; Stiegmann, Greg V

    2010-02-01

    Electrosurgery is used in virtually every laparoscopic operation. In the early days of laparoscopic surgery, capacitive coupling, associated with hybrid trocars, was thought to be the major cause of laparoscopic electrosurgery injuries. Modern laparoscopy has reduced capacitive coupling, and now insulation failure is thought to be the main cause of electrosurgical complications. The aim of this study was (1) to determine the incidence of insulation failures, (2) to compare the incidence of insulation failure in reusable and disposable instruments, and (3) to determine the location of insulation failures. At four major urban hospitals, reusable laparoscopic instruments were checked for insulation failure using a high-voltage porosity detector. Disposable L-hooks were collected following laparoscopic cholecystectomy and similarly evaluated for insulation failure. Instruments were determined to have insulation failure if 2.5 kV crossed the instrument's insulation to create a closed loop circuit. Statistical analysis was performed using Fisher's exact or chi(2) analysis (*denotes significance set at p < 0.05). Two hundred twenty-six laparoscopic instruments were tested (165 reusable). Insulation failure occurred more often in reusable (19%; 31/165) than in disposable instruments (3%; 2/61; *p < 0.01). When reusable sets were evaluated, 71% (12/17) were found to have at least one instrument with insulation failure. Insulation failure incidence in reusable instruments was similar between hospitals that routinely checked for insulation failure (19%; 25/130) and hospitals that do not routinely check for insulation failures (33%; 7/21; p = 0.16). Insulation failure was most common in the distal third of the instruments (54%; 25/46) compared to the middle or proximal third of the instruments (*p < 0.05). One in five reusable laparoscopic instruments has insulation failure; a finding that is not altered by whether the hospital routinely checks for insulation defects

  11. Heart Failure in South America

    PubMed Central

    Bocchi, Edimar Alcides

    2013-01-01

    Continued assessment of temporal trends in mortality and epidemiology of specific heart failure in South America is needed to provide a scientific basis for rational allocation of the limited health care resources, and strategies to reduce risk and predict the future burden of heart failure. The epidemiology of heart failure in South America was reviewed. Heart failure is the main cause of hospitalization based on available data from approximately 50% of the South American population. The main etiologies of heart failure are ischemic, idiopathic dilated cardiomyopathy, valvular, hypertensive and chagasic etiologies. In endemic areas, Chagas heart disease may be responsible by 41% of the HF cases. Also, heart failure presents high mortality especially in patients with Chagas etiology. Heart failure and etiologies associated with heart failure may be responsible for 6.3% of causes of deaths. Rheumatic fever is the leading cause of valvular heart disease. However, a tendency to reduction of HF mortality due to Chagas heart disease from 1985 to 2006, and reduction in mortality due to HF from 1999 to 2005 were observed in selected states in Brazil. The findings have important public health implications because the allocation of health care resources, and strategies to reduce risk of heart failure should also consider the control of neglected Chagas disease and rheumatic fever in South American countries. PMID:23597301

  12. Strategies of learning from failure.

    PubMed

    Edmondson, Amy C

    2011-04-01

    Many executives believe that all failure is bad (although it usually provides Lessons) and that Learning from it is pretty straightforward. The author, a professor at Harvard Business School, thinks both beliefs are misguided. In organizational life, she says, some failures are inevitable and some are even good. And successful learning from failure is not simple: It requires context-specific strategies. But first leaders must understand how the blame game gets in the way and work to create an organizational culture in which employees feel safe admitting or reporting on failure. Failures fall into three categories: preventable ones in predictable operations, which usually involve deviations from spec; unavoidable ones in complex systems, which may arise from unique combinations of needs, people, and problems; and intelligent ones at the frontier, where "good" failures occur quickly and on a small scale, providing the most valuable information. Strong leadership can build a learning culture-one in which failures large and small are consistently reported and deeply analyzed, and opportunities to experiment are proactively sought. Executives commonly and understandably worry that taking a sympathetic stance toward failure will create an "anything goes" work environment. They should instead recognize that failure is inevitable in today's complex work organizations.

  13. A zipper network model of the failure mechanics of extracellular matrices.

    PubMed

    Ritter, Michael C; Jesudason, Rajiv; Majumdar, Arnab; Stamenovic, Dimitrije; Buczek-Thomas, Jo Ann; Stone, Phillip J; Nugent, Matthew A; Suki, Béla

    2009-01-27

    Mechanical failure of soft tissues is characteristic of life-threatening diseases, including capillary stress failure, pulmonary emphysema, and vessel wall aneurysms. Failure occurs when mechanical forces are sufficiently high to rupture the enzymatically weakened extracellular matrix (ECM). Elastin, an important structural ECM protein, is known to stretch beyond 200% strain before failing. However, ECM constructs and native vessel walls composed primarily of elastin and proteoglycans (PGs) have been found to fail at much lower strains. In this study, we hypothesized that PGs significantly contribute to tissue failure. To test this, we developed a zipper network model (ZNM), in which springs representing elastin are organized into long wavy fibers in a zipper-like formation and placed within a network of springs mimicking PGs. Elastin and PG springs possessed distinct mechanical and failure properties. Simulations using the ZNM showed that the failure of PGs alone reduces the global failure strain of the ECM well below that of elastin, and hence, digestion of elastin does not influence the failure strain. Network analysis suggested that whereas PGs drive the failure process and define the failure strain, elastin determines the peak and failure stresses. Predictions of the ZNM were experimentally confirmed by measuring the failure properties of engineered elastin-rich ECM constructs before and after digestion with trypsin, which cleaves the core protein of PGs without affecting elastin. This study reveals a role for PGs in the failure properties of engineered and native ECM with implications for the design of engineered tissues.

  14. Rescue of Heart Failure by Mitochondrial Recovery.

    PubMed

    Marquez, Jubert; Lee, Sung Ryul; Kim, Nari; Han, Jin

    2016-03-01

    Heart failure (HF) is a multifactorial disease brought about by numerous, and oftentimes complex, etiological mechanisms. Although well studied, HF continues to affect millions of people worldwide and current treatments can only prevent further progression of HF. Mitochondria undoubtedly play an important role in the progression of HF, and numerous studies have highlighted mitochondrial components that contribute to HF. This review presents an overview of the role of mitochondrial biogenesis, mitochondrial oxidative stress, and mitochondrial permeability transition pore in HF, discusses ongoing studies that attempt to address the disease through mitochondrial targeting, and provides an insight on how these studies can affect future research on HF treatment.

  15. Intercultural health: proposals, actions and failures.

    PubMed

    Menéndez, Eduardo Luiz

    2016-01-01

    During the 1980s, 1990s and early 2000s,various intercultural health proposals and actions emerged in most Latin American countries. These initiatives aimed to integrate biomedicine with traditional medicine based on 'parallel' relationships, as opposed relationships based on exclusion, subordination and hegemony. These initiatives had two basic objectives:1) to contribute to the cultural rehabilitation of ethnic groups that made effective use of traditional medicine; and 2) to improve the quality of relationships between health professionals and indigenous patients. This paper analyzes the reasons for the limited impact and, in some cases, failure of such intercultural health initiatives.

  16. β-Blocker pharmacogenetics in heart failure

    PubMed Central

    Shin, Jaekyu

    2009-01-01

    β-Blockers (metoprolol, bisoprolol, and carvedilol) are a cornerstone of heart failure (HF) treatment. However, it is well recognized that responses to a β-blocker are variable among patients with HF. Numerous studies now suggest that genetic polymorphisms may contribute to variability in responses to a β-blocker, including left ventricular ejection fraction improvement, survival, and hospitalization due to HF exacerbation. This review summarizes the pharmacogenetic data for β-blockers in patients with HF and discusses the potential implications of β-blocker pharmacogenetics for HF patients. PMID:18437562

  17. Proprietes Adiabatiques des Naines Blanches Pulsantes de Type ZZ Ceti

    NASA Astrophysics Data System (ADS)

    Brassard, Pierre

    1992-01-01

    Cette these a pour but d'etudier les proprietes des oscillation non-radiales des etoiles ZZ Ceti, appelees aussi etoiles DA variables, dans le contexte de la theorie adiabatique des petites oscillations. Ces oscillations sont observables, pour ce type d'etoiles, sous forme de variations periodiques de la luminosite. A partir d'une analyse de modeles stellaires, analyse qui consiste principalement a calculer et a interpreter les periodes d'oscillations des modeles, nous voulons mieux connai tre les proprietes physiques fondamentales des ZZ Ceti. Nous developpons tout d'abord divers outils pour entreprendre cette etude. Apres avoir presente le formalisme mathematique de base decrivant les oscillations non-radiales d'une etoile, nous discutons des difficultes pouvant etre rencontrees dans le calcul de la frequence de Brunt-Vaisala, une quantite fondamentale pour le calcul des periodes d'oscillations. Par la suite, nous developpons un modele theorique simple permettant d'analyser et d'interpreter la structure des periodes calculees (ou observees) en termes des proprietes de structure de l'etoile. Nous presentons aussi les outils numeriques tout a fait originaux utilises pour calculer nos periodes a partir de modeles stellaires. Finalement, nous presentons les resultats d'ensemble de l'analyse de nos modeles, et discutons de l'interpretation des observations de periodes et du taux de variation de ces periodes en termes de structure de l'etoile et de composition du noyau de l'etoile, respectivement. Ces resultats representent l'etude la plus complete a ce jour de la seismologie des naines blanches.

  18. Public Choice, Market Failure, and Government Failure in Principles Textbooks

    ERIC Educational Resources Information Center

    Fike, Rosemarie; Gwartney, James

    2015-01-01

    Public choice uses the tools of economics to analyze how the political process allocates resources and impacts economic activity. In this study, the authors examine twenty-three principles texts regarding coverage of public choice, market failure, and government failure. Approximately half the texts provide coverage of public choice and recognize…

  19. Public Choice, Market Failure, and Government Failure in Principles Textbooks

    ERIC Educational Resources Information Center

    Fike, Rosemarie; Gwartney, James

    2015-01-01

    Public choice uses the tools of economics to analyze how the political process allocates resources and impacts economic activity. In this study, the authors examine twenty-three principles texts regarding coverage of public choice, market failure, and government failure. Approximately half the texts provide coverage of public choice and recognize…

  20. Comparing Learning from Productive Failure and Vicarious Failure

    ERIC Educational Resources Information Center

    Kapur, Manu

    2014-01-01

    A total of 136 eighth-grade math students from 2 Singapore schools learned from either productive failure (PF) or vicarious failure (VF). PF students "generated" solutions to a complex problem targeting the concept of variance that they had not learned yet before receiving instruction on the targeted concept. VF students…

  1. Impact of polymer hydrophilicity on biocompatibility: implication for DES polymer design.

    PubMed

    Hezi-Yamit, Ayala; Sullivan, Carol; Wong, Jennifer; David, Laura; Chen, Mingfei; Cheng, Peiwen; Shumaker, David; Wilcox, Josiah N; Udipi, Kishore

    2009-07-01

    Polymer coatings are essential for local delivery of drug from the stent platform. In designing a DES, it is critical to balance the hydrophilic and hydrophobic components of the polymer system to obtain optimal biocompatibility, while maintaining controlled drug elution. This study investigates the impact of polymer composition of the BioLinx polymer blend on in vitro biocompatibility, as measured by monocytic adhesion. Comparable evaluation was performed with polymers similar to those utilized in various DES that are currently being marketed. Relative hydrophilicities of polymer surfaces were determined through contact angle measurements and surface analyses. Polymer biocompatibility was evaluated in a novel in vitro assay system in which activated monocyte cells were exposed to polymer coated on 96-well plates. Enhanced monocyte adhesion was observed with polymers of a more hydrophobic nature, whereas those which were more hydrophilic did not induce activated monocyte adhesion. Our data supports the hypothesis that polymer composition is a feature that dictates in vitro biocompatibility as measured by monocyte driven inflammation. Monocyte adhesion has been shown to induce local inflammation as well as promote vascular cell proliferation factors contributing to in stent restenosis (Rogers et al., Arterioscler Thromb Vasc Biol 1996;16:1312-1318). Observed results suggest hydrophobic but not hydrophilic polymer surfaces support adhesion of activated monocytes to the polymer scaffold. The proprietary DES polymer blend BioLinx has a hydrophilic surface architecture and does not induce an inflammatory response as measured by these in vitro assays.

  2. Flight Deck Refuelling Hose Failure HMCS Preserver

    DTIC Science & Technology

    2000-01-01

    secondes. L’adherence de l’une des deux couches de renfort en fibres a la surface de caoutchouc etait egalement inferieure a la valeur prescrite. La...lb/po2 pendant 30 s. De plus, !’adherence d’une des couches de renfort en fibres sur la surface de caoutchouc etait inferieure a la valeur prescrite

  3. The use of biocompatible dialysis membranes in acute renal failure.

    PubMed

    Himmelfarb, J; Hakim, R M

    1997-04-01

    The interactions between blood and the dialysis membrane, aside from solute clearance, can be referred to as biocompatibility. It has increasingly been recognized that significant side effects may occur as a result of interactions of blood with the dialysis membrane itself. The use of unmodified cellulosic hemodialysis membranes results in potent activation of the alternative pathway of complement, and numerous investigators have now carefully defined the membrane characteristics that contribute to complement activation, adsorption, and clearance. Complement-dependent granulocyte activation during hemodialysis causes neutrophil degranulation and protease release, the production of reactive oxygen species, and modulation of granulocyte cell adhesion molecules. Recently, a number of experimental studies in animal models suggest that complement and granulocyte activation during hemodialysis could contribute to the prolongation of acute renal failure. Based on the hypothesis that hemodialysis with complement and granulocyte-activating membranes could contribute to the prolongation of acute renal failure and increased mortality, several recent prospective randomized clinical trials examining the role of membrane biocompatibility in the treatment of acute renal failure have been reported. Although not unanimous in their conclusions, most studies suggest that hemodialysis with more biocompatible membranes in patients with acute renal failure leads to a more rapid return of renal function and a lower morbidity and mortality. Thus, hemodialysis membrane biocompatibility may be an important contributor to the outcome of patients with acute renal failure who require dialysis.

  4. Electron transport chain defects in heart failure.

    PubMed

    Casademont, Jordi; Miró, Oscar

    2002-04-01

    In recent years, the possibility that disorders of cardiac metabolism play a role in the mechanisms that lead to ventricular dilatation and dysfunction in heart failure has attracted much attention. Electron transport chain is constituted by a series of multimeric protein complexes, located in the inner mitochondrial membranes, whose genes are distributed over both nuclear and mitochondrial DNA. Its normal function is essential to provide the energy for cardiac function. Many studies have described abnormalities in mitochondrial DNA genes encoding for electron transport chain (ETC) in dilated cardiomyopathies. In some cases, heart failure is one more or less relevant symptom among other multisystem manifestations characteristic of mitochondrial encephalomyopathies, being heart failure imputable to a primary mitochondrial disease. In the case of idiopathic dilated cardiomyopathies (IDC), many mitochondrial abnormalities have also been described using hystological, biochemical or molecular studies. The importance of such findings is under debate. The great variability in the mitochondrial abnormalities described has prompted the proposal that mitochondrial dysfunction could be a secondary phenomenon in IDC, and not a primary one. Among other possible explanations for such findings, the presence of an increased oxidative damage due to a free radical excess has been postulated. In this setting, the dysfunction of ETC could be a consequence, but also a cause of the presence of an increased free radical damage. Independently of its origin, ETC dysfunction may contribute to the persistence and worsening of heart failure. If this hypothesis, still to be proven, was certain, the modulation of cardiac metabolism could be an interesting approach to treat IDC. The precise mechanisms that lead to ventricular dilatation and dysfunction in heart failure are still nowadays poorly understood. Circumstances such as cytotoxic insults, viral infections, immune abnormalities

  5. La modelisation mathematique dans l'enseignement de la chimie des gaz a des eleves de la cinquieme annee du secondaire

    NASA Astrophysics Data System (ADS)

    Gauthier, Diane

    Les problemes d'enseignement de la chimie des gaz parfaits sont donc importants. Si plusieurs etudes ont ete realisees dans le but d'identifier et d'interpreter ces problemes, aucune recherche, a notre connaissance, n'a ete realisee sur l'enseignement des lois sur les gaz parfaits. Notre recherche sur l'enseignement est donc pionniere. Elle a pour objectif general de construire et d'analyser une sequence d'enseignement de la chimie des gaz comportant diverses situations de modelisation mathematique des conduites des gaz. Les principaux objectifs specifiques sont les suivants: (1) identifier et caracteriser les situations qui provoquent une evolution des conceptions naives des eleves, evolution vers des connaissances plus adequate sur les gaz; (2) identifier et caractEriser les situations qui provoquent une evolution des connaissances mathematiques des eleves leur permettant d'interpreter convenablement les resultats des experiences, d'eprouver leurs conceptions, de donner un sens aux notions et aux relations impliquees dans les lois des gaz parfaits, lois de Boyle-Mariotte et Gay-Lussac. Une sequence d'enseignement comportant huit situations est d'eleves de secondaire V. La construction de ces situations est orientee par les recherches sur les conceptions naives des eleves, par les etudes sur l'evolution historique des conceptions sur les gaz et des pratiques scientifiques, ainsi que par les etudes theoriques et empiriques realisees en didactique des sciences et des mathematiques. La methodologie de l'ingenierie didactique (Artigue, 1998) qui constitue une application de la theorie des situations didactiques (Brousseau, 1986) est utilisee dans la construction et l'analyse des situations d'enseignement. Une analyse a priori de chacune des situations d'enseignement est effectuee; elle a pour but dexpliquer les choix des taches qui font partie des situations et de preciser la gestion didactique des situations. Diverses situations d'enseignement de la chimie ont ainsi

  6. Heart failure: the pivotal role of histone deacetylases.

    PubMed

    Hewitson, Ruth; Dargan, James; Collis, David; Green, Aneta; Moorjani, Narain; Ohri, Sunil; Townsend, Paul A

    2013-02-01

    Heart failure, a state in which cardiac output is unable to meet the metabolic demands of the tissues, poses a significant health burden; following an initial hospital admission with heart failure, five-year mortality is close to 50%. Cardiac hypertrophy, characterised by increased cardiomyocyte size and protein synthesis, has deleterious effects when prolonged and contributes to heart failure. Cardiac hypertrophy itself increases risk of morbidity and mortality. Histone deacetylases are chromatin modifiers which deacetylate the N-terminal tails of histones and have been implicated in common cardiac pathologies associated with hypertrophy. There are 18 histone deacetylases separated into four classes. Class I histone deacetylases interact with heat shock proteins and are pro-hypertrophic, class IIa histone deacetylases repress hypertrophy by inhibiting the activity of transcription factors such as myocyte enhancer factor 2. Histone deacetylases present an exciting new target in combating cardiac hypertrophy and progression to heart failure.

  7. Role of Infections in Acute-on-Chronic Liver Failure.

    PubMed

    Moreau, Richard

    2015-01-01

    Patients with cirrhosis are prone to developing bacterial infections. Moreover, bacterial infection is the most common identifiable trigger of acute-on-chronic liver failure (ACLF), which is characterized by organ failures and a high risk of death. There is evidence of an excessive immune response of the host as a major mechanism leading to the development of organ failures in patients with cirrhosis. However, a role for direct tissue damage caused by bacterial toxins and virulence factors cannot be excluded. Failed tolerance mechanisms may also contribute to organ failures, although the involved mechanisms are unclear. A proportion of patients with infection-related ACLF have a prolonged stay in the intensive care unit. These patients have immune suppression, increased risk of superinfection and poor outcome. Immune suppression might be a consequence of the first infection episode that has led patients to be admitted to hospital.

  8. Diagnosis and management of heart failure in the fetus

    PubMed Central

    DAVEY, B.; SZWAST, A.; RYCHIK, J.

    2015-01-01

    Heart failure can be defined as the inability of the heart to sufficiently support the circulation. In the fetus, heart failure can be caused by a myriad of factors that include fetal shunting abnormalities, genetic cardiomyopathies, extracardiac malformations, arrhythmias and structural congenital heart disease. With advances in ultrasound has come the ability to characterize many complex conditions, previously poorly understood. Fetal echocardiography provides the tools necessary to evaluate and understand the various physiologies that contribute to heart failure in the fetus. In this review, we will explore the different mechanisms of heart failure in this unique patient population and highlight the role of fetal echocardiography in the current management of these conditions PMID:22992530

  9. Modeling Common Cause Failures of Thrusters on ISS Visiting Vehicles

    NASA Technical Reports Server (NTRS)

    Haught, Megan

    2014-01-01

    This paper discusses the methodology used to model common cause failures of thrusters on the International Space Station (ISS) Visiting Vehicles. The ISS Visiting Vehicles each have as many as 32 thrusters, whose redundancy makes them susceptible to common cause failures. The Global Alpha Model (as described in NUREG/CR-5485) can be used to represent the system common cause contribution, but NUREG/CR-5496 supplies global alpha parameters for groups only up to size six. Because of the large number of redundant thrusters on each vehicle, regression is used to determine parameter values for groups of size larger than six. An additional challenge is that Visiting Vehicle thruster failures must occur in specific combinations in order to fail the propulsion system; not all failure groups of a certain size are critical.

  10. Modeling Common Cause Failures of Thrusters on ISS Visiting Vehicles

    NASA Technical Reports Server (NTRS)

    Haught, Megan; Duncan, Gary

    2014-01-01

    This paper discusses the methodology used to model common cause failures of thrusters on the International Space Station (ISS) Visiting Vehicles. The ISS Visiting Vehicles each have as many as 32 thrusters, whose redundancy and similar design make them susceptible to common cause failures. The Global Alpha Model (as described in NUREG/CR-5485) can be used to represent the system common cause contribution, but NUREG/CR-5496 supplies global alpha parameters for groups only up to size six. Because of the large number of redundant thrusters on each vehicle, regression is used to determine parameter values for groups of size larger than six. An additional challenge is that Visiting Vehicle thruster failures must occur in specific combinations in order to fail the propulsion system; not all failure groups of a certain size are critical.

  11. Genetics and genomics of dilated cardiomyopathy and systolic heart failure.

    PubMed

    Tayal, Upasana; Prasad, Sanjay; Cook, Stuart A

    2017-02-22

    Heart failure is a major health burden, affecting 40 million people globally. One of the main causes of systolic heart failure is dilated cardiomyopathy (DCM), the leading global indication for heart transplantation. Our understanding of the genetic basis of both DCM and systolic heart failure has improved in recent years with the application of next-generation sequencing and genome-wide association studies (GWAS). This has enabled rapid sequencing at scale, leading to the discovery of many novel rare variants in DCM and of common variants in both systolic heart failure and DCM. Identifying rare and common genetic variants contributing to systolic heart failure has been challenging given its diverse and multiple etiologies. DCM, however, although rarer, is a reasonably specific and well-defined condition, leading to the identification of many rare genetic variants. Truncating variants in titin represent the single largest genetic cause of DCM. Here, we review the progress and challenges in the detection of rare and common variants in DCM and systolic heart failure, and the particular challenges in accurate and informed variant interpretation, and in understanding the effects of these variants. We also discuss how our increasing genetic knowledge is changing clinical management. Harnessing genetic data and translating it to improve risk stratification and the development of novel therapeutics represents a major challenge and unmet critical need for patients with heart failure and their families.

  12. Etude des chaines de spins par les methodes de la theorie quantique des champs

    NASA Astrophysics Data System (ADS)

    Allen, Dave

    Notre etude porte sur la chaine de spins en zigzag avec dimerisation dans le cas des spins 1/2 et 1. L'echelle de spin ordinaire et la chaine en zigzag simple en sont des cas particuliers. Dans la limite continue, ces systemes sont decrits par des modeles Wess-Zumino-Witten couples. Afin de pouvoir calculer les fonctions de correlation, nous exposons differentes equivalences quantiques permettant de simplifier les calculs. Dans le cas de chaines de spin 1/2, nous demontrons l'equivalence avec un modele de type Gross-Neveu, en fonction de fermions de Majorana; ces fermions decrivent alors les excitations elementaires du systeme. Nous exposons une vision classique de ces excitations afin de voir les mecanismes de confinement des spinons. Dans le cas de chaines de spin 1, l'etude est plus complexe. Nous pouvons decrire le systeme a l'aide de modeles sine-Gordon perturbes par de nombreuses interactions. En se limitant aux plus importantes, nous pouvons expliquer le comportement du gap en fonction du couplage interchaine observe numeriquement.

  13. Etude des defauts microscopiques et des proprietes optiques, electroniques et magnetiques du compose neodyme cerium oxyde de cuivre

    NASA Astrophysics Data System (ADS)

    Richard, Pierre

    La presente these, qui combine des mesures de diffusion Raman, de transmission infrarouge, de conductivite hyperfrequence et d'interferometrie ultrasonore sur les composes Nd 2-xCexCuO 4, traite des defauts d'oxygene, ainsi que des proprietes optiques, electroniques et magnetiques de ces materiaux. Les resultats experimentaux obtenus sont correles avec plusieurs donnees experimentales disponibles dans la litterature. D'abord, la caracterisation des modes Raman et des niveaux d'energie de champ cristallin de l'ion Nd3+ au moyen de techniques optiques, en fonction du dopage en cerium et du contenu en oxygene, permettent de conclure a la presence de defauts lies a une non-stoechiometrie en oxygene dans ces composes. En effet, des excitations de champ cristallin assignees a des ions Nd3+ en sites irreguliers sont observees, en plus des bandes d'absorption associees aux ions Nd3+ en site regulier, dans les spectres correspondant aux multiplets 4I11/2, 4I13/2 et 4I 15/2 de l'ion Nd3+. Les resultats experimentaux indiquent que, contrairement a la croyance largement repandue, les oxygenes apicaux, bien que presents dans les echantillons dopes, ne sont pas enleves lors du processus de reduction des echantillons necessaire pour faire apparaitre la supraconductivite dans cette famille de cuprates. Au contraire, des lacunes d'oxygene, dont le type varie en fonction du dopage, sont creees lors de ce processus. En particulier, il est montre dans ce travail que la reduction des echantillons dopes de maniere optimale conduit a la creation de lacunes d'oxygene dans les plans CuO2. Les consequences de telles lacunes sont largement discutees. En outre, il est suggere que de telles lacunes sont responsables de la perte de l'ordre antiferromagnetique a longue portee des ions Cu2+. Finalement, l'interaction d'echange anisotrope Nd3+-Cu 2+ dans le compose nondope est caracterisee au moyen de la transmission infrarouge sous champ magnetique. L'eclatement des doublets de Kramers mesure

  14. Diastolic heart failure: mechanisms and controversies.

    PubMed

    Ouzounian, Maral; Lee, Douglas S; Liu, Peter P

    2008-07-01

    Epidemiological and experimental studies have documented both the rising burden of diastolic heart failure (DHF) and several mechanisms that distinguish this disease from systolic heart failure (SHF). Controversies continue to surround the term 'DHF' as well as its existence as a pathophysiological entity distinct from SHF. Approximately half of all patients who present with heart failure have near-normal systolic function and predominately abnormal diastolic function. Recent reports counter the commonly held belief that survival of patients with DHF is better than that of patients with SHF. The challenges associated with managing the DHF phenotype arise from the heterogeneous etiologies of the condition that include aging, diabetes mellitus, hypertension and ischemia. Lack of diastolic distensibility in DHF has been attributed primarily to hypertrophy and fibrosis. Extracellular matrix and cytoskeletal components including matrix metalloproteinases, titin isoforms, and the quality and quantity of collagen are implicated in DHF development. Impaired active relaxation of the contractile apparatus also contributes to DHF. Novel therapeutic targets that address the pathophysiology of this disease are being actively explored, although as yet there are no proven therapies for DHF. New epidemiologic and mechanistic data regarding DHF highlight the urgency with which the scientific community must address this important public health problem.

  15. Vers des boites quantiques a base de graphene

    NASA Astrophysics Data System (ADS)

    Branchaud, Simon

    Le graphene est un materiau a base de carbone qui est etudie largement depuis 2004. De tres nombreux articles ont ete publies tant sur les proprietes electroniques, qu'optiques ou mecaniques de ce materiel. Cet ouvrage porte sur l'etude des fluctuations de conductance dans le graphene, et sur la fabrication et la caracterisation de nanostructures gravees dans des feuilles de ce cristal 2D. Des mesures de magnetoresistance a basse temperature ont ete faites pres du point de neutralite de charge (PNC) ainsi qu'a haute densite electronique. On trouve deux origines aux fluctuations de conductance pres du PNC, soit des oscillations mesoscopiques provenant de l'interference quantique, et des fluctuations dites Hall quantique apparaissant a plus haut champ (>0.5T), semblant suivre les facteurs de remplissage associes aux monocouches de graphene. Ces dernieres fluctuations sont attribuees a la charge d'etats localises, et revelent un precurseur a l'effet Hall quantique, qui lui, ne se manifeste pas avant 2T. On arrive a extraire les parametres caracterisant l'echantillon a partir de ces donnees. A la fin de cet ouvrage, on effectue des mesures de transport dans des constrictions et ilots de graphene, ou des boites quantiques sont formees. A partir de ces mesures, on extrait les parametres importants de ces boites quantiques, comme leur taille et leur energie de charge.

  16. 75 FR 63714 - Drawbridge Operation Regulation; Des Allemands Bayou, LA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-18

    ... Burlington Northern Santa Fe Railway swing bridge across Des Allemands Bayou, mile 14.0, in St. Charles and... Transportation, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590... INFORMATION: The Burlington Northern Santa Fe Railway swing span drawbridge across Bayou Des Allemands, mile...

  17. Peste des petits ruminants virus in Heilongjiang province, China, 2014.

    PubMed

    Wang, Jingfei; Wang, Miao; Wang, Shida; Liu, Zaisi; Shen, Nan; Si, Wei; Sun, Gang; Drewe, Julian A; Cai, Xuehui

    2015-04-01

    During March 25-May 5, 2014, we investigated 11 outbreaks of peste des petits ruminants in Heilongjiang Province, China. We found that the most likely source of the outbreaks was animals from livestock markets in Shandong. Peste des petits ruminants viruses belonging to lineages II and IV were detected in sick animals.

  18. Peste des Petits Ruminants Virus in Heilongjiang Province, China, 2014

    PubMed Central

    Wang, Miao; Wang, Shida; Liu, Zaisi; Shen, Nan; Si, Wei; Sun, Gang; Drewe, Julian A.; Cai, Xuehui

    2015-01-01

    During March 25–May 5, 2014, we investigated 11 outbreaks of peste des petits ruminants in Heilongjiang Province, China. We found that the most likely source of the outbreaks was animals from livestock markets in Shandong. Peste des petits ruminants viruses belonging to lineages II and IV were detected in sick animals. PMID:25811935

  19. 33 CFR 117.439 - Des Allemands Bayou.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Des Allemands Bayou. 117.439 Section 117.439 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.439 Des Allemands Bayou. (a) The...

  20. 33 CFR 117.439 - Des Allemands Bayou.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Des Allemands Bayou. 117.439 Section 117.439 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.439 Des Allemands Bayou. (a) The...

  1. 33 CFR 117.439 - Des Allemands Bayou.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Des Allemands Bayou. 117.439 Section 117.439 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.439 Des Allemands Bayou. (a) The...

  2. 33 CFR 117.439 - Des Allemands Bayou.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Des Allemands Bayou. 117.439 Section 117.439 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.439 Des Allemands Bayou. (a) The...

  3. 33 CFR 117.439 - Des Allemands Bayou.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Des Allemands Bayou. 117.439 Section 117.439 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.439 Des Allemands Bayou. (a) The...

  4. "Cognitive Style" and School Failure.

    ERIC Educational Resources Information Center

    Anderson, Kathryn M.

    Focusing on school failure among lower-class and minority children, the paper reexamines the relationship between "cognitive style" and school performance, and questions whether lower-class school failure really concerns cognitive performance at all. "Cognitive style" is defined as information processing habits which represent the learners'…

  5. Data Driven Device Failure Prediction

    DTIC Science & Technology

    2016-09-15

    solution is to use statistical machine learning to predict failure. However, since failure is still a relatively rare event, obtaining labelled training...52 15 Pre-Update, Memory Leak Support Vector Machine (SVM...37 9 Pre-Update, Memory Leak, Support Vector Machine (SVM) Confusion Matrix

  6. Compression failure of composite laminates

    NASA Technical Reports Server (NTRS)

    Pipes, R. B.

    1983-01-01

    This presentation attempts to characterize the compressive behavior of Hercules AS-1/3501-6 graphite-epoxy composite. The effect of varying specimen geometry on test results is examined. The transition region is determined between buckling and compressive failure. Failure modes are defined and analytical models to describe these modes are presented.

  7. Failure to Manage Constant Change

    ERIC Educational Resources Information Center

    McDonald, Ann

    2010-01-01

    This study examines patterns of system failure (communication, typographic, material, economic, maintenance) and the resulting workarounds in signs that are intended to communicate frequently changing information in the built environment. The observed failures and workarounds in the communication of ephemeral data and the accompanying narratives…

  8. Biomarkers in acute heart failure.

    PubMed

    Mallick, Aditi; Januzzi, James L

    2015-06-01

    The care of patients with acutely decompensated heart failure is being reshaped by the availability and understanding of several novel and emerging heart failure biomarkers. The gold standard biomarkers in heart failure are B-type natriuretic peptide and N-terminal pro-B-type natriuretic peptide, which play an important role in the diagnosis, prognosis, and management of acute decompensated heart failure. Novel biomarkers that are increasingly involved in the processes of myocardial injury, neurohormonal activation, and ventricular remodeling are showing promise in improving diagnosis and prognosis among patients with acute decompensated heart failure. These include midregional proatrial natriuretic peptide, soluble ST2, galectin-3, highly-sensitive troponin, and midregional proadrenomedullin. There has also been an emergence of biomarkers for evaluation of acute decompensated heart failure that assist in the differential diagnosis of dyspnea, such as procalcitonin (for identification of acute pneumonia), as well as markers that predict complications of acute decompensated heart failure, such as renal injury markers. In this article, we will review the pathophysiology and usefulness of established and emerging biomarkers for the clinical diagnosis, prognosis, and management of acute decompensated heart failure. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  9. Heart Failure Society of America

    MedlinePlus

    ... March 31, 2017 The United Network for Organ Sharing (UNOS) asks the Heart Failure Society of America (HFSA) members to comment on the proposed Organ Procurement and Transplant... Highlights Video from the Managing the Economic Challenges in the Treatment of Heart Failure (Non- ...

  10. Failure criteria for viscoelastic materials

    NASA Technical Reports Server (NTRS)

    Knauss, W. G.

    1974-01-01

    Research projects concerned with developing a theory of fracture of materials are discussed. The effects of the geometry of the structure and the loads acting on the structure as they influence the failure process are analyzed. The effects of the viscoelastic deformation characteristics of the bulk elastomer on failure behavior are examined. Additional material parameters which control the fracture process are identified.

  11. Failure detection system risk reduction assessment

    NASA Technical Reports Server (NTRS)

    Aguilar, Robert B. (Inventor); Huang, Zhaofeng (Inventor)

    2012-01-01

    A process includes determining a probability of a failure mode of a system being analyzed reaching a failure limit as a function of time to failure limit, determining a probability of a mitigation of the failure mode as a function of a time to failure limit, and quantifying a risk reduction based on the probability of the failure mode reaching the failure limit and the probability of the mitigation.

  12. Failure to recall.

    PubMed

    Laming, Donald

    2009-01-01

    Mathematical analysis shows that if the pattern of rehearsal in free-recall experiments (of necessity, the pattern observed when participants rehearse aloud) be continued without any further interruption by stimuli (as happens during recall), it terminates with the retrieval of the same 1 word over and over again. Such a terminal state is commonly reached before some of the words in the list have been retrieved even once; those words are not recalled. The 1 minute frequently allowed for recall in free-recall experiments is ample time for retrieval to seize up in this way. The author proposes a model that represents the essential features of the pattern of rehearsal; validates that model by reference to the overt rehearsal data from B. B. Murdock, Jr., and J. Metcalfe (1978) and the recall data from B. B. Murdock, Jr., and R. Okada (1970); demonstrates the long-term properties of continued sequences of retrievals and, also, a fundamental relation linking recall to the total time of presentation; and, finally, compares failure to recall in free-recall experiments with forgetting in general.

  13. Acute liver failure.

    PubMed

    Blackmore, Laura; Bernal, William

    2015-10-01

    Acute liver failure (ALF) is a rare critical illness with high mortality whose successful management requires early recognition and effective initial management. Though it may result from a wide variety of causes, in the UK and much of the developed world most cases result from paracetamol-induced hepatotoxicity, and administration of antidotal N-acetyl cysteine at first recognition is key. Involvement of local critical care services should occur at an early stage for stabilisation, monitoring and supportive care with parallel discussion with specialist liver centres to identify those patients who may benefit from transfer. Prognostic criteria are applied to identify patients for emergency liver transplantation, and candidates for surgery are prioritised on waitlisting schemes. Outcomes now approach that of elective surgery. However, the majority of cases, and particularly those with paracetamol-induced disease, recover with supportive medical care alone. Overall outcomes for patients with ALF have improved dramatically over the last three decades, but mortality remains unacceptable and further advances in care are required.

  14. Pharmacotherapy of autonomic failure

    PubMed Central

    Shibao, Cyndya; Okamoto, Luis; Biaggioni, Italo

    2012-01-01

    The clinical picture of autonomic failure is characterized by severe and disabling orthostatic hypotension. These disorders can develop as a result of damage of central neural pathways or peripheral autonomic nerves, caused either by a primary autonomic neurodegenerative disorder or secondary to systemic illness. Treatment should be focused on decreasing presyncopal symptoms instead of achieving blood pressure goals. Non-pharmacologic strategies such as physical counter-maneuvers, dietary changes (i.e. high salt diet, rapid water drinking or compression garments) are the first line therapy. Affected patients should be screened for co-morbid conditions such as post-prandial hypotension and supine hypertension that can worsen orthostatic hypotension if not treated. If symptoms are not controlled with these conservative measures the next step is to start pharmacological agents; these interventions should be aimed at increasing intravascular volume either by promoting water and salt retention (fludrocortisone) or by increasing red blood cell mass when anemia is present (recombinant erythropoietin). When pressor agents are needed, direct pressor agents (midodrine) or agents that potentiate sympathetic activity (atomoxetine, yohimbine, pyridostigmine) can be used. It is preferable to use short-acting pressor agents that can be taken on as needed basis in preparation for upright activities. PMID:21664375

  15. Rethinking Heart Failure

    PubMed Central

    Fürstenwerth, Hauke

    2012-01-01

    An increasing body of clinical observations and experimental evidence suggests that cardiac dysfunction results from autonomic dysregulation of the contractile output of the heart. Excessive activation of the sympathetic nervous system and a decrease in parasympathetic tone are associated with increased mortality. Elevated levels of circulating catecholamines closely correlate with the severity and poor prognosis in heart failure. Sympathetic over-stimulation causes increased levels of catecholamines, which induce excessive aerobic metabolism leading to excessive cardiac oxygen consumption. Resulting impaired mitochondrial function causes acidosis, which results in reduction in blood flow by impairment of contractility. To the extent that the excessive aerobic metabolism resulting from adrenergic stimulation comes to a halt the energy deficit has to be compensated for by anaerobic metabolism. Glucose and glycogen become the essential nutrients. Beta-adrenergic blockade is used successfully to decrease hyperadrenergic drive. Neurohumoral antagonists block adrenergic over-stimulation but do not provide the heart with fuel for compensatory anaerobic metabolism. The endogenous hormone ouabain reduces catecholamine levels in healthy volunteers, promotes the secretion of insulin, induces release of acetylcholine from synaptosomes and potentiates the stimulation of glucose metabolism by insulin and acetylcholine. Ouabain stimulates glycogen synthesis and increases lactate utilisation by the myocardium. Decades of clinical experience with ouabain confirm the cardioprotective effects of this endogenous hormone. The so far neglected sympatholytic and vagotonic effects of ouabain on myocardial metabolism clearly make a clinical re-evaluation of this endogenous hormone necessary. Clinical studies with ouabain that correspond to current standards are warranted. PMID:28352413

  16. Growth factors and acute renal failure.

    PubMed

    Hirschberg, R; Ding, H

    1998-03-01

    During acute renal injury, there are alterations in the expression of several growth factors and their receptors in the kidney. The increased expression of several growth factors and/or their receptors at sites of nephron injury suggests important contributions to repair. Exogenous administration of some growth factors, such as IGF-I, EGF and HGF, accelerates recovery of renal function in experimental acute renal failure (ARF). In ARF growth factors act through several mechanisms, which may include altered cell cycle regulation and mitogenesis, differentiation of recovered cells, regulation of apoptosis, improved renal hemodynamics, and others. There is evidence for interactions of growth factors with other growth factors as well as with other genes resulting in complex orchestration of biologic events contributing to recovery from ARF.

  17. Intelligent Design and Intelligent Failure

    NASA Technical Reports Server (NTRS)

    Jerman, Gregory

    2015-01-01

    Good Evening, my name is Greg Jerman and for nearly a quarter century I have been performing failure analysis on NASA's aerospace hardware. During that time I had the distinct privilege of keeping the Space Shuttle flying for two thirds of its history. I have analyzed a wide variety of failed hardware from simple electrical cables to cryogenic fuel tanks to high temperature turbine blades. During this time I have found that for all the time we spend intelligently designing things, we need to be equally intelligent about understanding why things fail. The NASA Flight Director for Apollo 13, Gene Kranz, is best known for the expression "Failure is not an option." However, NASA history is filled with failures both large and small, so it might be more accurate to say failure is inevitable. It is how we react and learn from our failures that makes the difference.

  18. Right side of heart failure.

    PubMed

    Guglin, Maya; Verma, Sameer

    2012-05-01

    The function of the right ventricle (RV) in heart failure (HF) has been mostly ignored until recently. A 2006 report of the National Heart, Lung, and Blood Institute identified a gap between RV research efforts and its clinical importance compared with that of the left ventricle. This recent shift in paradigm is fueled by the prognostic value ascribed to RV failure in HF and morbidity/mortality after myocardial infarction and surgery. In this review, we examine the significance of RV failure in the HF setting, its clinical presentation and pathophysiology, and ways to evaluate RV function using echocardiographic measurements. Furthermore, we discuss the medical management of RV failure including traditional therapies like beta-blockers and newer options like nitric oxide, phosphodiesterase inhibitors, and calcium sensitizers. Mechanical support is also examined. Finally, this review places an emphasis on RV failure in the setting of left ventricular assist devices and heart transplantation.

  19. Pure autonomic failure without synucleinopathy.

    PubMed

    Isonaka, Risa; Holmes, Courtney; Cook, Glen A; Sullivan, Patti; Sharabi, Yehonatan; Goldstein, David S

    2017-04-01

    Pure autonomic failure is a rare form of chronic autonomic failure manifesting with neurogenic orthostatic hypotension and evidence of sympathetic noradrenergic denervation unaccompanied by signs of central neurodegeneration. It has been proposed that pure autonomic failure is a Lewy body disease characterized by intra-neuronal deposition of the protein alpha-synuclein in Lewy bodies and neurites. A middle-aged man with previously diagnosed pure autonomic failure experienced a sudden, fatal cardiac arrest. He was autopsied, and tissues were harvested for neurochemical and immunofluorescence studies. Post-mortem microscopic neuropathology showed no Lewy bodies, Lewy neurites, or alpha-synuclein deposition by immunohistochemistry anywhere in the brain. The patient had markedly decreased immunofluorescent tyrosine hydroxylase in sympathetic ganglion tissue without detectable alpha-synuclein even in rare residual nests of tyrosine hydroxylase-containing ganglionic fibers. In pure autonomic failure, sympathetic noradrenergic denervation can occur without concurrent Lewy bodies or alpha-synuclein deposition in the brain or sympathetic ganglion tissue.

  20. [Premature ovarian failure: present aspects].

    PubMed

    Vilodre, Luiz Cesar; Moretto, Marcelo; Kohek, Maria Beatriz da Fonte; Spritzer, Poli Mara

    2007-08-01

    Premature ovarian failure occurs in approximately 1:1000 women before 30 years, 1:250 by 35 years and 1:100 by the age of 40. It is characterized by primary or secondary amenorrhea and cannot be considered as definitive because spontaneous conception may occur in 5 to 10% of cases. In 95% of cases, premature ovarian failure is sporadic. The known causes of premature ovarian failure include chromosomal defects, autoimmune diseases, exposure to radiation or chemotherapy, surgical procedures, and certain drugs. Frequently, however, the etiology is not clear and these cases are considered to be idiopathic. Premature ovarian failure is defined by gonadal failure and high serum follicle-stimulating hormone (FSH) levels. Clinical approach includes emotional support, hormonal therapy with estrogens and progesterone or progestogens, infertility treatment, and prevention of osteoporosis and potential cardiovascular risk.

  1. Medical therapy for spermatogenic failure

    PubMed Central

    Ramasamy, Ranjith; Stahl, Peter J; Schlegel, Peter N

    2012-01-01

    Medical treatment of men with primary spermatogenic failure remains largely ineffective in contrast to those with secondary testicular failure. Treatment has been attempted with a multitude of agents ranging from hormones to nutritional supplements (antioxidants). While some studies have demonstrated benefit to some treatments, no treatments have consistently demonstrated efficacy nor has it been possible to reliably identify patients likely to benefit. Idiopathic spermatogenic failure likely results from multiple discrete defects in sperm production that are as yet unidentified. A better understanding of these defects will yield more effective treatment options and appropriate triage of patients to specific therapeutic regimens. This review focuses on the rationale and current evidence for hormonal and antioxidant therapy in medical treatment of male infertility, spermatogenic failure in particular. Although empiric medical therapy for spermatogenic failure has been largely replaced by assisted reproductive techniques, both treatment modalities could play a role, perhaps as combination therapy. PMID:22179517

  2. STS-3 main parachute failure

    NASA Technical Reports Server (NTRS)

    Runkle, R.; Henson, K.

    1982-01-01

    A failure analysis of the parachute on the Space Transportation System 3 flight's solid rocket booster's is presented. During the reentry phase of the two Solid Rocket Boosters (SRBs), one 115 ft diameter main parachute failed on the right hand SRB (A12). This parachute failure caused the SRB to impact the Ocean at 110 ft/sec in lieu of the expected 3 parachute impact velocity of 88 ft/sec. This higher impact velocity relates directly to more SRB aft skirt and more motor case damage. The cause of the parachute failure, the potential risks of losing an SRB as a result of this failure, and recommendations to ensure that the probability of chute failures of this type in the future will be low are discussed.

  3. Etude du processus de changement vecu par des familles ayant decide d'adopter volontairement des comportements d'attenuation des changements climatiques

    NASA Astrophysics Data System (ADS)

    Leger, Michel T.

    Les activites humaines energivores telles l'utilisation intensive de l'automobile, la surconsommation de biens et l'usage excessif d'electricite contribuent aux changements climatiques et autres problemes environnementaux. Bien que plusieurs recherches rapportent que l'etre humain est de plus en plus conscient de ses impacts sur le climat de la planete, ces memes recherches indiquent qu'en general, les gens continuent a se comporter de facon non ecologique. Que ce soit a l'ecole ou dans la communaute, plusieurs chercheurs en education relative a l'environnement estiment qu'une personne bien intentionnee est capable d'adopter des comportements plus respectueux de l'environnement. Le but de cette these etait de comprendre le processus d'integration de comportements d'attenuation des changements climatiques dans des familles. A cette fin, nous nous sommes fixe deux objectifs : 1) decrire les competences et les procedes qui favorisent l'adoption de comportements d'attenuation des changements climatiques dans des familles et 2) decrire les facteurs et les dynamiques familiales qui facilitent et limitent l'adoption de comportements d'attenuation des changements climatiques dans des familles. Des familles ont ete invitees a essayer des comportements personnels et collectifs d'attenuation des changements climatiques de sorte a integrer des modes de vie plus ecologiques. Sur une periode de huit mois, nous avons suivi leur experience de changement afin de mieux comprendre comment se produit le processus de changement dans des familles qui decident volontairement d'adopter des comportements d'attenuation des changements climatiques. Apres leur avoir fourni quelques connaissances de base sur les changements climatiques, nous avons observe le vecu de changement des familles durant huit mois d'essais a l'aide de journaux reflexifs, d'entretiens d'explicitation et du journal du chercheur. La these comporte trois articles scientifiques. Dans le premier article, nous presentons une

  4. Anisotropie des coefficients de diffusion dans des cristaux liquides discotiques hexagonaux

    NASA Astrophysics Data System (ADS)

    Daoud, M.; Gharbia, M.; Gharbi, A.

    1994-06-01

    The diffusion constants of dyes in several hexagonal discotic liquid crystals are measured and discussed. For all the liquid crystals studied, these constants are anisotropic : the diffusion in the direction parallel to the columns is faster than that in the perpendicular plane (frac{D_allel}{D_perp}>1). The effects of the length and shape of the chains bound to the triphenylene discs are shown. The effect of the dye molecular size is also described. The study of the diffusion coefficients of hexapentoxytriphenylene (C5HET) as a function of temperature has shown that the activation energies along the columns and perpendicular to the columns are comparable. The main features of dye diffusion in the hexagonal columnar liquid crystals studied are similar to those reported in nematic phases. Les mesures des constantes de diffusion de colorants dans plusieurs cristaux liquides discotiques hexagonaux sont présentées et discutées. Pour tous les cristaux liquides étudiés, ces constantes présentent une anisotropie, avec une diffusion plus rapide parallèlement aux colonnes que perpendiculairement à celles-ci (frac{D_allel}{D_perp}>1). Des effets de longueur et de forme des chaînes branchées sur les disques de triphénylène sont mis en évidence. Il en est de même pour la taille des molécules de colorants. L'étude en fonction de la température a montré que dans le cas de l'hexapentoxytriphénylène (C5HET), les énergies d'activation dans les directions parallèle et perpendiculaire aux colonnes sont comparables. Les caractéristiques de la diffusion de colorants dans les cristaux liquides colonnaires hexagonaux étudiés sont semblables à celles des nématiques.

  5. Etude de la dynamique des porteurs dans des nanofils de silicium par spectroscopie terahertz

    NASA Astrophysics Data System (ADS)

    Beaudoin, Alexandre

    Ce memoire presente une etude des proprietes de conduction electrique et de la dynamique temporelle des porteurs de charges dans des nanofils de silicium sondes par rayonnement terahertz. Les cas de nanofils de silicium non intentionnellement dopes et dopes type n sont compares pour differentes configurations du montage experimental. Les mesures de spectroscopie terahertz en transmission montre qu'il est possible de detecter la presence de dopants dans les nanofils via leur absorption du rayonnement terahertz (˜ 1--12 meV). Les difficultes de modelisation de la transmission d'une impulsion electromagnetique dans un systeme de nanofils sont egalement discutees. La detection differentielle, une modification au systeme de spectroscopie terahertz, est testee et ses performances sont comparees au montage de caracterisation standard. Les instructions et des recommendations pour la mise en place de ce type de mesure sont incluses. Les resultats d'une experience de pompe optique-sonde terahertz sont egalement presentes. Dans cette experience, les porteurs de charge temporairement crees suite a l'absorption de la pompe optique (lambda ˜ 800 nm) dans les nanofils (les photoporteurs) s'ajoutent aux porteurs initialement presents et augmentent done l'absorption du rayonnement terahertz. Premierement, l'anisotropie de l'absorption terahertz et de la pompe optique par les nanofils est demontree. Deuxiemement, le temps de recombinaison des photoporteurs est etudie en fonction du nombre de photoporteurs injectes. Une hypothese expliquant les comportements observes pour les nanofils non-dopes et dopes-n est presentee. Troisiemement, la photoconductivite est extraite pour les nanofils non-dopes et dopes-n sur une plage de 0.5 a 2 THz. Un lissage sur la photoconductivite permet d'estimer le nombre de dopants dans les nanofils dopes-n. Mots-cles: nanofil, silicium, terahertz, conductivite, spectroscopie, photoconductivite.

  6. Etude des systèmes protoplanétaires

    NASA Astrophysics Data System (ADS)

    Augereau, Jean-Charles

    2000-11-01

    Les disques de poussières et de gaz autour des étoiles rejoignant la Séquence Principale sont les sites de formation des planètes extra-solaires dont l'existence s'est vu confirmée récemment. Cette thèse aborde l'étude de la poussière des environnements circumstellaires. Elle associe des observations spatiales à haute résolution angulaire, la modélisation des propriétés physico-chimiques des poussières et leur comportement optique, la modélisation des disques optiquement fins et la dynamique des planétésimaux à l'origine des grains observés autour des étoiles âgées. Les images obtenues avec le Télescope Spatial Hubble révèlent deux nouveaux disques circumstellaires autour des étoiles HD 141569 et HD 100546, parfois classées dans la catégorie des étoiles de Herbig. Bien que les systèmes présentent des âges proches (~10 millions d'années), les morphologies très différentes des disques mettent en évidence la difficulté pour élaborer un scénario unique d'évolution des systèmes protoplanétaires. L'anneau fin de poussières autour de HR 4796A, une étoile d'âge similaire aux précédentes, est marginalement résolu depuis le sol. La modélisation complète de ce disque permet de reproduire l'ensemble des observations disponibles. Ces résultats impliquent la présence de planétésimaux, à un âge aussi peu avancé, pour repeupler le disque en poussières poreuses et essentiellement amorphes qui sont soufflées par la pression de radiation. Une modélisation dynamique du prototypique disque autour de β Pictoris est proposée. Associée à une description réaliste du comportement optique des grains, cette approche reproduit les caractéristiques générales du disque ainsi que des asymétries plus fines en supposant la présence d'une planète dans un disque de planétésimaux et en tenant compte des effets différentiels de la pression de radiation sur les grains. Enfin, le modèle de disques que j'ai développé est exploit

  7. Procedure for Failure Mode, Effects, and Criticality Analysis (FMECA)

    NASA Technical Reports Server (NTRS)

    1966-01-01

    This document provides guidelines for the accomplishment of Failure Mode, Effects, and Criticality Analysis (FMECA) on the Apollo program. It is a procedure for analysis of hardware items to determine those items contributing most to system unreliability and crew safety problems.

  8. Boiler tube failure reduction program

    SciTech Connect

    Lamping, G.A. ); Jonas, O. ); Niebo, R.J. )

    1991-08-01

    Boiler tube failures are generally recognized as the major cause of forced outages of fossil power generating units for US electric utilities. In almost all cases of serious availability losses, the boiler tube failures are repeat in nature and result in multiple forced outages. Primary factors influencing repeat, rather than random, tube failures are usually found to result from not following state-of-the-art operating, maintenance and/or engineering practices, lack of proper tube failure analysis, wrong choice of corrective/preventive action or solution, and lack of a tube failure reporting and monitoring system. A proven way to prevent costly repeat failures is to implement a formalized Boiler Tube Failure Prevention Program that is supported by senior management and focuses attention and resources on operating, maintenance and engineering controllable parameters that influence repeat tube failures. This report describes such a program, implemented at sixteen utilities under EPRI Research Project RP 1890-7, Boiler Tube Failure Reduction Program.'' Results are presented for ten utilities that began the program in the summer of 1986 with over four years of participation, and for six additional utilities from June of 1988 through December 1990. Both sets of utilities have produced remarkable improvements, the most tangible being substantial reductions in equivalent availability factor losses due to BTF of between 1.5 to 4.5%. Failure mechanism data submitted to the North American Electric Reliability Council (NERC) over the project term has also made it possible to delineate the leading BTF mechanisms causing problems for the participating utilities. Corrosion fatigue, fly ash erosion and high temperature creep accounted for over 28% of the total reported. 3 figs.

  9. Hans Bethe : Des etoiles a la bombe

    NASA Astrophysics Data System (ADS)

    Bonnet-Bidaud, J. M.

    1996-06-01

    Il comprit le premier comment brillent les etoiles. Il fut aussi de cette poignee de scientifiques qui, dans le secret de Los Alamos, mirent au point la tristement celebre bombe atomique. Hans Bethe est l'un des derniers geants qui auront marque la physique de ce siecle d'une empreinte indelebile. C'est dans le bureau 01 du prestigieux laboratoire Kellog de l'institut Caltech qu'il a bien voulu retracer pour nous son impressionnante carriere, et revenir sur les motivations qui ont guide ses pas.

  10. Le traitement familial des enfants et des adolescents anorexiques : Des lignes directrices pour le médecin communautaire

    PubMed Central

    Findlay, S; Pinzon, J; Taddeo, D; Katzman, DK

    2010-01-01

    L’anorexie mentale (AM) est une maladie grave qui met la vie en danger et qui fait généralement son apparition pendant l’adolescence. Les données probantes au sujet du traitement optimal de l’AM chez les enfants et les adolescents sont en croissance, mais il reste beaucoup à apprendre. Même si les démarches thérapeutiques actuelles varient au Canada et ailleurs, les données jusqu’à présent indiquent que le traitement familial (TF) est le plus efficace pour les enfants et les adolescents anorexiques. Un élément essentiel du modèle de TF, c’est que les parents sont investis de la responsabilité de rétablir la santé physique de leur enfant et de s’assurer de la reprise complète de son poids. Le médecin qui comprend les principes fondamentaux et la philosophie du TF peut mettre en place les éléments de cette intervention fondée sur des faits probants auprès des jeunes patients anorexiques et de leur famille.

  11. Failure studies on rubber and rubber composites

    NASA Astrophysics Data System (ADS)

    Tao, Zhenghong

    A research study has been conducted to investigate selected failure processes in rubber and rubbery composites. Specific failure modes and materials considered included mechanical tearing of rubber-coated fabrics and mechanical/thermal fatigue of carbon black-filled elastomers. Experimental efforts developed novel evaluation techniques that were used to access failure resistance of the materials, as well as to elucidate molecular structure/physical properties relationships. Results are presented in multi-monograph format consisting of a series of four interdependent papers published in peer-reviewed journals. The first monograph measures the tear resistance of a series of polyester fabrics, of controlled fill-yarn size, coated with a compounded butyl rubber resin. A constrained trouser tear test is used to quantify the role of yarn mobility on crack-tip development and the resultant tear strength. As the area around a propagating crack is constrained, tear strength decreases by several orders of magnitude, indicating that the ability of the composite structure to dissipate energy away from the crack tip contributes more to tear resistance than the intrinsic strength of the concomitant materials. Monograph number two continues the work of the first by developing a novel cutting technique to monitor the role of the fiber/rubber interphase during tear propagation. This approach was applied to five different elastomers coated onto one of the polyester yarns. These data show a threefold increase in strength is possible by proper optimization of the fiber/rubber bond. In the third monograph, five different rubber bushing compounds were evaluated for mechanical/thermal fatigue resistance. Samples were dynamically excited in combined compression and shear loadings using a specially designed test fixture. Results indicated that heat build-up was a major contributing factor to the eventual failure of the materials via a complex fracture mechanism, with epoxidized natural

  12. Exercise and heart failure in the elderly.

    PubMed

    Kappagoda, Tissa; Amsterdam, Ezra A

    2012-09-01

    In this review, we will examine the physiological responses to exercise in elderly populations (age > 65 years) with and without evidence of heart failure. Aging per se in both men and women is associated with a ~40% lower maximum oxygen consumption in sedentary subjects. In trained individuals, this value is 25-32% lower. A smaller SV accounts for nearly 50% of these age-related differences, and the remainder is explained by a lower maximal HR and reduced oxygen extraction. Exercise training is also associated with an increase in the arteriovenous O(2) difference in previously sedentary elderly men and women, which probably contributes to the overall beneficial effect of training in the elderly. However, during vigorous exercise (125 W), the cardiac output in the elderly is dependent upon an age-related increase in end-diastolic volume and stroke volume, which "compensates" partially for the age-related decrease in heart rate. Hence, in elderly individuals, the stroke volume during exercise depends upon diastolic filling. The changes that occur in the heart are also associated with an overall reduction in efferent sympathetic nerve activity. Despite this decline, the metaboreflex initiated by receptors in exercising muscles remains the main determinant of sympathetic activation (to maintain blood pressure) during exercise in the elderly. It is recognized that aging is associated with the development of heart failure, particularly in women in whom its prevalence increases >twofold from age 65-69 (6.6%) to age 85 years (14%). Almost half the people presenting with heart failure appear to have normal left ventricular systolic function, a phenomenon that is more common in women. Exercise training in elderly people with and without heart failure appears to have a beneficial effect in terms of enhancing the quality of life and functional capacity. Mortality benefit in the latter has not been established with certainty.

  13. Preventing medical errors by designing benign failures.

    PubMed

    Grout, John R

    2003-07-01

    One way to successfully reduce medical errors is to design health care systems that are more resistant to the tendencies of human beings to err. One interdisciplinary approach entails creating design changes, mitigating human errors, and making human error irrelevant to outcomes. This approach is intended to facilitate the creation of benign failures, which have been called mistake-proofing devices and forcing functions elsewhere. USING FAULT TREES TO DESIGN FORCING FUNCTIONS: A fault tree is a graphical tool used to understand the relationships that either directly cause or contribute to the cause of a particular failure. A careful analysis of a fault tree enables the analyst to anticipate how the process will behave after the change. EXAMPLE OF AN APPLICATION: A scenario in which a patient is scalded while bathing can serve as an example of how multiple fault trees can be used to design forcing functions. The first fault tree shows the undesirable event--patient scalded while bathing. The second fault tree has a benign event--no water. Adding a scald valve changes the outcome from the undesirable event ("patient scalded while bathing") to the benign event ("no water") Analysis of fault trees does not ensure or guarantee that changes necessary to eliminate error actually occur. Most mistake-proofing is used to prevent simple errors and to create well-defended processes, but complex errors can also result. The utilization of mistake-proofing or forcing functions can be thought of as changing the logic of a process. Errors that formerly caused undesirable failures can be converted into the causes of benign failures. The use of fault trees can provide a variety of insights into the design of forcing functions that will improve patient safety.

  14. Report of the NASA Ad Hoc Committee on failure of high strength structural materials

    NASA Technical Reports Server (NTRS)

    Brown, W. F., Jr. (Editor)

    1972-01-01

    An analysis of structural failures that have occurred in NASA programs was conducted. Reports of 231 examples of structural failure were reviewed. Attempts were made to identify those factors which contributed to the failures, and recommendations were formulated for actions which would minimize their effects on future NASA programs. Two classes of factors were identified: (1) those associated with deficiencies in existing materials and structures technology and (2) those attributable to inadequate documentation or communication of that technology.

  15. Estimating the probability of failure when testing reveals no failures

    NASA Technical Reports Server (NTRS)

    Miller, Keith W.; Morell, Larry J.; Noonan, Robert E.; Park, Stephen K.; Nicol, David M.; Murrill, Branson W.; Voas, Jeffrey M.

    1992-01-01

    Formulas for estimating the probability of failure when testing reveals no errors are introduced. These formulas incorporate random testing results, information about the input distribution, and prior assumptions about the probability of failure of the software. The formulas are not restricted to equally likely input distributions, and the probability of failure estimate can be adjusted when assumptions about the input distribution change. The formulas are based on a discrete sample space statistical model of software and include Bayesian prior assumptions. Reusable software and software in life-critical applications are particularly appropriate candidates for this type of analysis.

  16. Estimating the probability of failure when testing reveals no failures

    NASA Technical Reports Server (NTRS)

    Miller, Keith W.; Morell, Larry J.; Noonan, Robert E.; Park, Stephen K.; Nicol, David M.; Murrill, Branson W.; Voas, Jeffrey M.

    1992-01-01

    Formulas for estimating the probability of failure when testing reveals no errors are introduced. These formulas incorporate random testing results, information about the input distribution, and prior assumptions about the probability of failure of the software. The formulas are not restricted to equally likely input distributions, and the probability of failure estimate can be adjusted when assumptions about the input distribution change. The formulas are based on a discrete sample space statistical model of software and include Bayesian prior assumptions. Reusable software and software in life-critical applications are particularly appropriate candidates for this type of analysis.

  17. Accidental knowledge: Using accidents and other project failures to inform research in systems engineering

    NASA Astrophysics Data System (ADS)

    Sorenson, Diane C.

    Projects experience cost overruns, late deliveries, quality issues, cancellation, and accidents despite the best efforts of the systems engineering community. There is relatively little research on why systems engineering failures in general happen, but a substantial body of work on accident causation. Here, we investigate whether systems failures in general exhibit the same patterns of causation as accidents. We conducted a review of existing accident models to develop a model that could be applied to all types of project failures. Our model helped us to classify where the factors occur during the system development/system operation phases and which entity was involved in each factor. We analyzed 58 failure case studies. The failure cases span non-accidents, accidents, and dual failures. The sources for each subset had varying depth and scope of investigation. We developed a coding method to compare the factors between failure cases that broke each factor down into an "actor-action-object" structure. We further generalized the actions from the "actor-action-object" strings into control flaws so that we could analyze the failure cases at a high level. We analyzed the control flaws, actions, and actors for each failure case and compared the results for accidents and non-accidents. Of our results that we could not attribute to study biases, we found similarities and differences between project failure causation. We also identified which control flaws, actions, and actors were the most prevalent in the different types of project failures. Of all the actions, "failure to consider factor in system development" contributed most to non-accidents, while "failure to consider step in risk management" contributed the most to accidents. Of all the actors, "company management" contributed the most to non-accidents and accidents.

  18. Acute decompensated heart failure and the cardiorenal syndrome.

    PubMed

    Liang, Kelly V; Williams, Amy W; Greene, Eddie L; Redfield, Margaret M

    2008-01-01

    Heart failure is one of the leading causes of hospitalizations in the United States. Concomitant and significant renal dysfunction is common in patients with heart failure. Increasingly, the syndrome of heart failure is one of cardiorenal failure, in which concomitant cardiac and renal dysfunctions exist, with each accelerating the progression of the other. One fourth of patients hospitalized for the treatment of acute decompensated heart failure will experience significant worsening of renal function, which is associated with worse outcomes. It remains unclear whether worsening renal function specifically contributes to poor outcomes or whether it is merely a marker of advanced cardiac and renal dysfunction. Diuretic resistance, with or without worsening renal function, is also common in acute decompensated heart failure, although the definition of diuretic resistance, its prevalence, and prognostic implications are less well defined. The term cardiorenal syndrome has been variably associated with cardiorenal failure, worsening renal function, and diuretic resistance but is more comprehensively defined as a state of advanced cardiorenal dysregulation manifest by one or all of these specific features. The pathophysiology of the cardiorenal syndrome is poorly understood and likely involves interrelated hemodynamic and neurohormonal mechanisms. When conventional therapy for acute decompensated heart failure fails, mechanical fluid removal via ultrafiltration, hemofiltration, or hemodialysis may be needed for refractory volume overload. While ultrafiltration can address diuretic resistance, whether ultrafiltration prevents worsening renal function or improves outcomes in patients with cardiorenal syndrome remains unclear. Evidence regarding the potential renal-preserving effects of nesiritide is mixed, and further studies on the efficacy and safety of different doses of nesiritide in heart failure therapy are warranted. Newer therapeutic agents, including vasopressin

  19. Heart failure among Indigenous Australians: a systematic review

    PubMed Central

    2012-01-01

    Background Cardiovascular diseases contribute substantially to the poor health and reduced life expectancy of Indigenous Australians. Heart failure is a common, disabling, progressive and costly complication of these disorders. The epidemiology of heart failure and the adequacy of relevant health service provision in Indigenous Australians are not well delineated. Methods A systematic search of the electronic databases PubMed, Embase, Web of Science, Cinahl Plus, Informit and Google Scholar was undertaken in April 2012 for peer-reviewed journal articles relevant to the topic of heart failure in Indigenous Australians. Additionally, a website search was done to identify other pertinent publications, particularly government reports. Results There was a paucity of relevant peer-reviewed research, and government reports dominated the results. Ten journal articles, 1 published conference abstract and 10 reports were eligible for inclusion. Indigenous Australians reportedly have higher morbidity and mortality from heart failure than their non-Indigenous counterparts (age-standardised prevalence ratio 1.7; age-standardised hospital separation ratio ≥3; crude per capita hospital expenditure ratio 1.58; age-adjusted mortality ratio >2). Despite the evident disproportionate burden of heart failure in Indigenous Australians, the accuracy of estimation from administrative data is limited by poor indigenous identification, inadequate case ascertainment and exclusion of younger subjects from mortality statistics. A recent journal article specifically documented a high prevalence of heart failure in Central Australian Aboriginal adults (5.3%), noting frequent undiagnosed disease. One study examined barriers to health service provision for Indigenous Australians in the context of heart failure. Conclusions Despite the shortcomings of available published data, it is clear that Indigenous Australians have an excess burden of heart failure. Emerging data suggest that undiagnosed

  20. Coordination des regulateurs conventionnels des machines Synchrones et des Compensateurs Statiques (SVCs)

    NASA Astrophysics Data System (ADS)

    Zabaiou, Tarik

    This thesis proposes a new control design method based on wide-area measurements to coordinate generator excitations and Static Var Compensator (SVC) auxiliary controls. A state space model of a multimachine power system that includes a SVC is first derived. This model has several specific characteristics. The interactions between SVC and generator variables are clearly shown and the interactions among the generators are also quantified. Generators terminal voltages are used as state variables instead of internal field voltages and damper winding flux linkages. The benefit is that the proposed model state variables are easily measurable. Moreover, it is a hierarchical approach and suitable for wide-area control design in large power systems. Next, remote measurements are used to generate coordinating signals for the generator excitations and the SVC. The coordinating controller decouples the system dynamics by compensating the interaction terms. The effectiveness of the new control strategy is tested on Anderson and Farmer four-generator nine-bus power system. Simulation results demonstrate that both local and inter-area oscillations are well damped when the global controller is used. Furthermore, Relative Gain Array (RGA) theory is proposed to evaluate the interactions and to select the input global signals for the coordinate controller. Only signals that contribute to the strongest interactions are used by the controller to considerably reduce or eliminate the interactions between the system components. The second controller with a reduced set of measurements is compared to the first controller with full measurements. Results show that performances of both controllers are very similar. They provide significant additional damping for power oscillations and increase the power transfer in the system. Communication time delay effects are also considered in this study. The simulation results show that coordinating controller performances are excellent when realistic

  1. Premature ovarian failure

    PubMed Central

    Beck-Peccoz, Paolo; Persani, Luca

    2006-01-01

    Premature ovarian failure (POF) is a primary ovarian defect characterized by absent menarche (primary amenorrhea) or premature depletion of ovarian follicles before the age of 40 years (secondary amenorrhea). It is a heterogeneous disorder affecting approximately 1% of women <40 years, 1:10,000 women by age 20 and 1:1,000 women by age 30. The most severe forms present with absent pubertal development and primary amenorrhea (50% of these cases due to ovarian dysgenesis), whereas forms with post-pubertal onset are characterized by disappearance of menstrual cycles (secondary amenorrhea) associated with premature follicular depletion. As in the case of physiological menopause, POF presents by typical manifestations of climacterium: infertility associated with palpitations, heat intolerance, flushes, anxiety, depression, fatigue. POF is biochemically characterized by low levels of gonadal hormones (estrogens and inhibins) and high levels of gonadotropins (LH and FSH) (hypergonadotropic amenorrhea). Beyond infertility, hormone defects may cause severe neurological, metabolic or cardiovascular consequences and lead to the early onset of osteoporosis. Heterogeneity of POF is also reflected by the variety of possible causes, including autoimmunity, toxics, drugs, as well as genetic defects. POF has a strong genetic component. X chromosome abnormalities (e.g. Turner syndrome) represent the major cause of primary amenorrhea associated with ovarian dysgenesis. Despite the description of several candidate genes, the cause of POF remains undetermined in the vast majority of the cases. Management includes substitution of the hormone defect by estrogen/progestin preparations. The only solution presently available for the fertility defect in women with absent follicular reserve is ovum donation. PMID:16722528

  2. Failure environment analysis tool applications

    NASA Technical Reports Server (NTRS)

    Pack, Ginger L.; Wadsworth, David B.

    1994-01-01

    Understanding risks and avoiding failure are daily concerns for the women and men of NASA. Although NASA's mission propels us to push the limits of technology, and though the risks are considerable, the NASA community has instilled within it, the determination to preserve the integrity of the systems upon which our mission and, our employees lives and well-being depend. One of the ways this is being done is by expanding and improving the tools used to perform risk assessment. The Failure Environment Analysis Tool (FEAT) was developed to help engineers and analysts more thoroughly and reliably conduct risk assessment and failure analysis. FEAT accomplishes this by providing answers to questions regarding what might have caused a particular failure; or, conversely, what effect the occurrence of a failure might have on an entire system. Additionally, FEAT can determine what common causes could have resulted in other combinations of failures. FEAT will even help determine the vulnerability of a system to failures, in light of reduced capability. FEAT also is useful in training personnel who must develop an understanding of particular systems. FEAT facilitates training on system behavior, by providing an automated environment in which to conduct 'what-if' evaluation. These types of analyses make FEAT a valuable tool for engineers and operations personnel in the design, analysis, and operation of NASA space systems.

  3. Failure environment analysis tool applications

    NASA Technical Reports Server (NTRS)

    Pack, Ginger L.; Wadsworth, David B.

    1993-01-01

    Understanding risks and avoiding failure are daily concerns for the women and men of NASA. Although NASA's mission propels us to push the limits of technology, and though the risks are considerable, the NASA community has instilled within, the determination to preserve the integrity of the systems upon which our mission and, our employees lives and well-being depend. One of the ways this is being done is by expanding and improving the tools used to perform risk assessment. The Failure Environment Analysis Tool (FEAT) was developed to help engineers and analysts more thoroughly and reliably conduct risk assessment and failure analysis. FEAT accomplishes this by providing answers to questions regarding what might have caused a particular failure; or, conversely, what effect the occurrence of a failure might have on an entire system. Additionally, FEAT can determine what common causes could have resulted in other combinations of failures. FEAT will even help determine the vulnerability of a system to failures, in light of reduced capability. FEAT also is useful in training personnel who must develop an understanding of particular systems. FEAT facilitates training on system behavior, by providing an automated environment in which to conduct 'what-if' evaluation. These types of analyses make FEAT a valuable tool for engineers and operations personnel in the design, analysis, and operation of NASA space systems.

  4. Periodontitis in Chronic Heart Failure.

    PubMed

    Fröhlich, Hanna; Herrmann, Kristina; Franke, Jennifer; Karimi, Alamara; Täger, Tobias; Cebola, Rita; Katus, Hugo A; Zugck, Christian; Frankenstein, Lutz

    2016-08-01

    Periodontal disease has been associated with an increased risk of cardiovascular events. The purpose of our study was to investigate whether a correlation between periodontitis and chronic heart failure exists, as well as the nature of the underlying cause. We enrolled 71 patients (mean age, 54 ± 13 yr; 56 men) who had stable chronic heart failure; all underwent complete cardiologic and dental evaluations. The periodontal screening index was used to quantify the degree of periodontal disease. We compared the findings to those in the general population with use of data from the 4th German Dental Health Survey. Gingivitis, moderate periodontitis, and severe periodontitis were present in 17 (24%), 17 (24%), and 37 (52%) patients, respectively. Severe periodontitis was more prevalent among chronic heart failure patients than in the general population. In contrast, moderate periodontitis was more prevalent in the general population (P <0.00001). The severity of periodontal disease was not associated with the cause of chronic heart failure or the severity of heart failure symptoms. Six-minute walking distance was the only independent predictor of severe periodontitis. Periodontal disease is highly prevalent in chronic heart failure patients regardless of the cause of heart failure. Prospective trials are warranted to clarify the causal relationship between both diseases.

  5. Periodontitis in Chronic Heart Failure

    PubMed Central

    Fröhlich, Hanna; Herrmann, Kristina; Franke, Jennifer; Karimi, Alamara; Täger, Tobias; Cebola, Rita; Katus, Hugo A.; Zugck, Christian

    2016-01-01

    Periodontal disease has been associated with an increased risk of cardiovascular events. The purpose of our study was to investigate whether a correlation between periodontitis and chronic heart failure exists, as well as the nature of the underlying cause. We enrolled 71 patients (mean age, 54 ± 13 yr; 56 men) who had stable chronic heart failure; all underwent complete cardiologic and dental evaluations. The periodontal screening index was used to quantify the degree of periodontal disease. We compared the findings to those in the general population with use of data from the 4th German Dental Health Survey. Gingivitis, moderate periodontitis, and severe periodontitis were present in 17 (24%), 17 (24%), and 37 (52%) patients, respectively. Severe periodontitis was more prevalent among chronic heart failure patients than in the general population. In contrast, moderate periodontitis was more prevalent in the general population (P <0.00001). The severity of periodontal disease was not associated with the cause of chronic heart failure or the severity of heart failure symptoms. Six-minute walking distance was the only independent predictor of severe periodontitis. Periodontal disease is highly prevalent in chronic heart failure patients regardless of the cause of heart failure. Prospective trials are warranted to clarify the causal relationship between both diseases. PMID:27547136

  6. Energy metabolism in heart failure

    PubMed Central

    Ventura-Clapier, Renée; Garnier, Anne; Veksler, Vladimir

    2004-01-01

    Heart failure (HF) is a syndrome resulting from the inability of the cardiac pump to meet the energy requirements of the body. Despite intensive work, the pathogenesis of the cardiac intracellular abnormalities that result from HF remains incompletely understood. Factors that lead to abnormal contraction and relaxation in the failing heart include metabolic pathway abnormalities that result in decreased energy production, energy transfer and energy utilization. Heart failure also affects the periphery. Patients suffering from heart failure always complain of early muscular fatigue and exercise intolerance. This is linked in part to intrinsic alterations of skeletal muscle, among which decreases in the mitochondrial ATP production and in the transfer of energy through the phosphotransfer kinases play an important role. Alterations in energy metabolism that affect both cardiac and skeletal muscles argue for a generalized metabolic myopathy in heart failure. Recent evidence shows that decreased expression of mitochondrial transcription factors and mitochondrial proteins are involved in mechanisms causing the energy starvation in heart failure. This review will focus on energy metabolism alterations in long-term chronic heart failure with only a few references to compensated hypertrophy when necessary. It will briefly describe the energy metabolism of normal heart and skeletal muscles and their alterations in chronic heart failure. It is beyond the scope of this review to address the metabolic switches occurring in compensated hypertrophy; readers could refer to well-documented reviews on this subject. PMID:14660709

  7. Perception of Leitmotives in Richard Wagner's Der Ring des Nibelungen.

    PubMed

    Baker, David J; Müllensiefen, Daniel

    2017-01-01

    The music of Richard Wagner tends to generate very diverse judgments indicative of the complex relationship between listeners and the sophisticated musical structures in Wagner's music. This paper presents findings from two listening experiments using the music from Wagner's Der Ring des Nibelungen that explores musical as well as individual listener parameters to better understand how listeners are able to hear leitmotives, a compositional device closely associated with Wagner's music. Results confirm findings from a previous experiment showing that specific expertise with Wagner's music can account for a greater portion of the variance in an individual's ability to recognize and remember musical material compared to measures of generic musical training. Results also explore how acoustical distance of the leitmotives affects memory recognition using a chroma similarity measure. In addition, we show how characteristics of the compositional structure of the leitmotives contributes to their salience and memorability. A final model is then presented that accounts for the aforementioned individual differences factors, as well as parameters of musical surface and structure. Our results suggest that that future work in music perception may consider both individual differences variables beyond musical training, as well as symbolic features and audio commonly used in music information retrieval in order to build robust models of musical perception and cognition.

  8. Perception of Leitmotives in Richard Wagner's Der Ring des Nibelungen

    PubMed Central

    Baker, David J.; Müllensiefen, Daniel

    2017-01-01

    The music of Richard Wagner tends to generate very diverse judgments indicative of the complex relationship between listeners and the sophisticated musical structures in Wagner's music. This paper presents findings from two listening experiments using the music from Wagner's Der Ring des Nibelungen that explores musical as well as individual listener parameters to better understand how listeners are able to hear leitmotives, a compositional device closely associated with Wagner's music. Results confirm findings from a previous experiment showing that specific expertise with Wagner's music can account for a greater portion of the variance in an individual's ability to recognize and remember musical material compared to measures of generic musical training. Results also explore how acoustical distance of the leitmotives affects memory recognition using a chroma similarity measure. In addition, we show how characteristics of the compositional structure of the leitmotives contributes to their salience and memorability. A final model is then presented that accounts for the aforementioned individual differences factors, as well as parameters of musical surface and structure. Our results suggest that that future work in music perception may consider both individual differences variables beyond musical training, as well as symbolic features and audio commonly used in music information retrieval in order to build robust models of musical perception and cognition. PMID:28522981

  9. Failure Analysis and Mechanisms of Failure of Fibrous Composite Structures

    NASA Technical Reports Server (NTRS)

    Noor, A. K. (Compiler); Shuart, M. J. (Compiler); Starnes, J. H., Jr. (Compiler); Williams, J. G. (Compiler)

    1983-01-01

    The state of the art of failure analysis and current design practices, especially as applied to the use of fibrous composite materials in aircraft structures is discussed. Deficiencies in these technologies are identified, as are directions for future research.

  10. Failure probability under parameter uncertainty.

    PubMed

    Gerrard, R; Tsanakas, A

    2011-05-01

    In many problems of risk analysis, failure is equivalent to the event of a random risk factor exceeding a given threshold. Failure probabilities can be controlled if a decisionmaker is able to set the threshold at an appropriate level. This abstract situation applies, for example, to environmental risks with infrastructure controls; to supply chain risks with inventory controls; and to insurance solvency risks with capital controls. However, uncertainty around the distribution of the risk factor implies that parameter error will be present and the measures taken to control failure probabilities may not be effective. We show that parameter uncertainty increases the probability (understood as expected frequency) of failures. For a large class of loss distributions, arising from increasing transformations of location-scale families (including the log-normal, Weibull, and Pareto distributions), the article shows that failure probabilities can be exactly calculated, as they are independent of the true (but unknown) parameters. Hence it is possible to obtain an explicit measure of the effect of parameter uncertainty on failure probability. Failure probability can be controlled in two different ways: (1) by reducing the nominal required failure probability, depending on the size of the available data set, and (2) by modifying of the distribution itself that is used to calculate the risk control. Approach (1) corresponds to a frequentist/regulatory view of probability, while approach (2) is consistent with a Bayesian/personalistic view. We furthermore show that the two approaches are consistent in achieving the required failure probability. Finally, we briefly discuss the effects of data pooling and its systemic risk implications.

  11. Owning Failure: Insights into the Perceptions and Understandings of Art Educators

    ERIC Educational Resources Information Center

    Fremantle, Chris; Kearney, Gemma

    2015-01-01

    Failure forms an important dimension of art and design and is inherent in creative endeavours. This article explores current literature on failure in the art and design context and offers a contribution through qualitative research drawing upon interviews with lecturing staff in a UK art school. The findings from this research emphasise the…

  12. Owning Failure: Insights into the Perceptions and Understandings of Art Educators

    ERIC Educational Resources Information Center

    Fremantle, Chris; Kearney, Gemma

    2015-01-01

    Failure forms an important dimension of art and design and is inherent in creative endeavours. This article explores current literature on failure in the art and design context and offers a contribution through qualitative research drawing upon interviews with lecturing staff in a UK art school. The findings from this research emphasise the…

  13. The polymerization and thrombin-binding properties of des-(B beta 1-42)-fibrin.

    PubMed

    Siebenlist, K R; DiOrio, J P; Budzynski, A Z; Mosesson, M W

    1990-10-25

    Multiple factors affect the thrombin-catalyzed conversion of fibrinogen to fibrin, including: fibrinopeptide (FPA and FPB) release leading to exposure of two types of polymerization domains ("A" and "B," respectively) in the central portion of the molecule, and exposure of a noncatalytic "secondary" thrombin-binding site in fibrin. Fibrinogen containing the FPA sequence but lacking the B beta 1-42 sequence ("des-(B beta 1-42)-fibrinogen"), was compared to native fibrinogen (containing both FPA and FPB) to investigate the role played by B beta 1-42 in the polymerization of alpha-fibrin (i.e. fibrin lacking FPA), to compare reptilase and thrombin cleavage of FPA from fibrinogen, and to explore the location and function of the secondary thrombin-binding site. Electron microscopy of evolving polymer structures (mu, 0.14; pH 7.4) plus turbidity measurements, showed that early thin fibril formation as well as subsequent lateral fibril associations were impaired in des-(B beta 1-42)-alpha-fibrin, thus indicating that the B beta 1-42 sequence contributes to the A polymerization site. Reptilase-activated des-(B beta 1-42)-alpha-fibrin polymerized even more slowly than thrombin-activated des-(B beta 1-42)-alpha-fibrin, differences that disappeared when repolymerization of preformed fibrin monomers was carried out. Since existing data indicate that thrombin releases FPA in a concerted manner, resulting in relatively rapid evolution of fully functional divalent alpha-fibrin monomers, it can be inferred that delayed fibrin assembly of reptilase fibrin is due to slower formation of divalent alpha-fibrin monomers. Thrombin-activated des-(B beta 1-42)-alpha-fibrin polymerized more rapidly at low ionic strength (mu, 0.04) than did native alpha,beta-fibrin, a reversal of their behavior at physiological ionic strength (mu, 0.14). Concomitant measurement of FPA release revealed modest slowing of release at low ionic strength from des-(B beta 1-42)-fibrinogen (t1/2, 36.5 versus 21

  14. Outpatient Emergencies: Acute Heart Failure.

    PubMed

    Mysliwiec, Malgorzata; Bonita, Raphael E

    2017-05-01

    Heart failure is an epidemic in the United States and a major health problem worldwide. The syndrome of acute heart failure is marked by a recent onset of symptoms usually in terms of days to a few weeks of worsening fatigue, shortness of breath, orthopnea, swelling, and sudden onset of weight gain. Physicians caring for patients with heart failure must know the risk factors for this disease, pathophysiology, symptomatology, important examination findings, key diagnostic tests, and management approach so as to improve symptoms and reduce mortality. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Management of Postoperative Respiratory Failure.

    PubMed

    Mulligan, Michael S; Berfield, Kathleen S; Abbaszadeh, Ryan V

    2015-11-01

    Despite best efforts, postoperative complications such as postoperative respiratory failure may occur and prompt recognition of the process and management is required. Postoperative respiratory failure, such as postoperative pneumonia, postpneumonectomy pulmonary edema, acute respiratory distress-like syndromes, and pulmonary embolism, are associated with high morbidity and mortality. The causes of these complications are multifactorial and depend on preoperative, intraoperative, and postoperative factors, some of which are modifiable. The article identifies some of the risk factors, causes, and treatment strategies for successful management of the patient with postoperative respiratory failure. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Wind Turbine Failures - Tackling current Problems in Failure Data Analysis

    NASA Astrophysics Data System (ADS)

    Reder, M. D.; Gonzalez, E.; Melero, J. J.

    2016-09-01

    The wind industry has been growing significantly over the past decades, resulting in a remarkable increase in installed wind power capacity. Turbine technologies are rapidly evolving in terms of complexity and size, and there is an urgent need for cost effective operation and maintenance (O&M) strategies. Especially unplanned downtime represents one of the main cost drivers of a modern wind farm. Here, reliability and failure prediction models can enable operators to apply preventive O&M strategies rather than corrective actions. In order to develop these models, the failure rates and downtimes of wind turbine (WT) components have to be understood profoundly. This paper is focused on tackling three of the main issues related to WT failure analyses. These are, the non-uniform data treatment, the scarcity of available failure analyses, and the lack of investigation on alternative data sources. For this, a modernised form of an existing WT taxonomy is introduced. Additionally, an extensive analysis of historical failure and downtime data of more than 4300 turbines is presented. Finally, the possibilities to encounter the lack of available failure data by complementing historical databases with Supervisory Control and Data Acquisition (SCADA) alarms are evaluated.

  17. Contribution au developpement d'une methode de controle des procedes dans une usine de bouletage

    NASA Astrophysics Data System (ADS)

    Gosselin, Claude

    This thesis, a collaborative effort between Ecole de technologie superieure and ArcelorMittal Company, presents the development of a methodology for monitoring and quality control of multivariable industrial production processes. This innovation research mandate was developed at ArcelorMittal Exploitation Miniere (AMEM) pellet plant in Port-Cartier (Quebec, Canada). With this undertaking, ArcelorMittal is striving to maintain its world class level of excellence and continues to pursue initiatives that can augment its competitive advantage worldwide. The plant's gravimetric classification process was retained as a prototype and development laboratory due to its effect on the company's competitiveness and its impact on subsequent steps leading to final production of iron oxide pellets. Concretely, the development of this expertise in process control and in situ monitoring will establish a firm basic knowledge in the fields of complex system physical modeling, data reconciliation, statistical observers, multivariate command and quality control using real-time monitoring of the desirability function. The hydraulic classifier is mathematically modeled. Using planned disturbances on the production line, an identification procedure was established to provide empirical estimations of the model's structural parameters. A new sampling campaign and a previously unpublished data collection and consolidation policy were implemented plant-wide. Access to these invaluable data sources has enabled the establishment of new thresholds that govern the production process and its control. Finally, as a substitute for the traditional quality control process, we have implemented a new strategy based on the use of the desirability function. Our innovation is not in using this Finally, as a substitute for the traditional quality control process, we have implemented a new strategy based on the use of the desirability function. Our innovation is not in using this function as an indicator of overall (economic) satisfaction in the production process, but rather in proposing it as an "observer" of the system's state. The first implementation steps have already demonstrated the method's feasibility as well as other numerous industrial impacts on production processes within the company. Namely, the emergence of the economical aspect as a strategic variable that assures better governance of production processes where quality variables present strategic issues.

  18. Contribution a l'auscultation des chaussees mixtes par methodes GPR et electrique

    NASA Astrophysics Data System (ADS)

    Kaouane, Carole

    Quebec's infrastructures are ageing. A reliable, quick and economical assessment of the state of urban roads would help to plan civil engineering. This M.Sc. thesis aims to investigate and develop the potential of Ground Penetrating Radar (GPR) and electrical methods to assess pavement condition subject to wetting, freezing and drying cycles. The objectives are to display defects and estimate water content in the materials used for the mixed pavement construction; these consist in layers of asphalt (top), concrete (middle) and grade and sub-grade (bottom). Prior studies showed a valuable potential of joint application of GPR and electrical resistivity to assess mixed pavement condition. These studies were mainly based on numerical modeling and some site tests using both methods. It was concluded that a better evaluation of the potential of the coupled methods would come from the assessment of physical properties and validation from geotechnical evidences. At first, we characterized the context. Structural defects and water content implied modification of physical properties of road materials. After running numerical modeling, we carried out an experiment in one of the streets in Montreal (Canada) where pavement needed complete rehabilitation. GPR surveys were carried out before the pavement was destroyed and removed, and subsequently a resistivity imaging was carried out on the subgrade layer. We also sampled blocks of asphalt and concrete along the street from the demolition rubble in order to study their physical properties in the lab. Soil samples were taken from trenches to measure water content. The grade and sub-grade were mainly a mix of clayey-silt and gravel, as the embedding ground is grey clay. We measured the complex dielectric constants of asphalt and concrete in the range 50 MHz-900 MHz with a recently developed dielectric probe sampling a volume of 30 cm3. Resistivity measurements were also performed on large cores of asphalt and concrete using an inhouse system. Measurements were carried out on dry and wet samples, which provided a range of values encompassing the climatic conditions for the whole year. Finally the physical property and geotechnical data were used as input to numerical modeling and the modeled responses compared to the survey data. The predicted data fit nicely with the observed data. This work aims to provide further information for a better calibration of geophysical devices in pavement condition assessment. Moreover, it gives a wide range of information, which could become a base for further and more specific works.

  19. [Failures regarding the treatment plan].

    PubMed

    Lecocq, Guillaume

    2016-03-01

    Who has never had a treatment failure? Who has never regretted launching into a treatment plan? And who has never vowed to avoid falling again into the same trap? All of us, of course. Which simply allowed us to fall into other traps once we'd pulled ourselves out of our previous failures. And to start with, do we believe that a successful outcome means achieving a molar and canine bilateral Class I, a normal overjet and overbite, and centered and coinciding midlines? So, does that make any other kind of treatment plan a recipe for failure? In more realistic mode, we should consider a treatment plan a failure when we are unable to achieve the objectives we set ourselves at the beginning of treatment, due to a lack of realism, or excessive optimism...

  20. Intestinal Failure (Short Bowel Syndrome)

    MedlinePlus

    ... N Vitamin deficiencies as a result of poor absorption in the intestine N Electrolyte and mineral deficiencies ... N Kidney stones or gallstones due to poor absorption of calcium or bile How is intestinal failure ...