Science.gov

Sample records for failure contribution des

  1. 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…

  2. 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

    2013-08-01

    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. PMID:23747781

  3. 7 CFR 1485.21 - Failure to make required contribution.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Failure to make required contribution. 1485.21 Section 1485.21 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS COOPERATIVE AGREEMENTS FOR THE DEVELOPMENT OF FOREIGN MARKETS...

  4. 47 CFR 54.713 - Contributors' failure to report or to contribute.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... to contribute. (a) A contributor that fails to file a Telecommunications Reporting Worksheet and... filing of an untruthful or inaccurate Telecommunications Reporting Worksheet, failure to file the Telecommunications Reporting Worksheet, or late payment of contributions. Failure to file the...

  5. 47 CFR 54.713 - Contributors' failure to report or to contribute.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... to contribute. (a) A contributor that fails to file a Telecommunications Reporting Worksheet and... filing of an untruthful or inaccurate Telecommunications Reporting Worksheet, failure to file the Telecommunications Reporting Worksheet, or late payment of contributions. Failure to file the...

  6. 47 CFR 54.713 - Contributors' failure to report or to contribute.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... to contribute. (a) A contributor that fails to file a Telecommunications Reporting Worksheet and... filing of an untruthful or inaccurate Telecommunications Reporting Worksheet, failure to file the Telecommunications Reporting Worksheet, or late payment of contributions. Failure to file the...

  7. 47 CFR 54.713 - Contributors' failure to report or to contribute.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... to contribute. (a) A contributor that fails to file a Telecommunications Reporting Worksheet and... filing of an untruthful or inaccurate Telecommunications Reporting Worksheet, failure to file the Telecommunications Reporting Worksheet, or late payment of contributions. Failure to file the...

  8. 47 CFR 54.713 - Contributors' failure to report or to contribute.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... to contribute. (a) A contributor that fails to file a Telecommunications Reporting Worksheet and... filing of an untruthful or inaccurate Telecommunications Reporting Worksheet, failure to file the Telecommunications Reporting Worksheet, or late payment of contributions. Failure to file the...

  9. 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...

  10. 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.

  11. Dispersal failure contributes to plant losses in NW Europe.

    PubMed

    Ozinga, Wim A; Römermann, Christine; Bekker, Renée M; Prinzing, Andreas; Tamis, Wil L M; Schaminée, Joop H J; Hennekens, Stephan M; Thompson, Ken; Poschlod, Peter; Kleyer, Michael; Bakker, Jan P; van Groenendael, Jan M

    2009-01-01

    The ongoing decline of many plant species in Northwest Europe indicates that traditional conservation measures to improve the habitat quality, although useful, are not enough to halt diversity losses. Using recent databases, we show for the first time that differences between species in adaptations to various dispersal vectors, in combination with changes in the availability of these vectors, contribute significantly to explaining losses in plant diversity in Northwest Europe in the 20th century. Species with water- or fur-assisted dispersal are over-represented among declining species, while others (wind- or bird-assisted dispersal) are under-represented. Our analysis indicates that the 'colonization deficit' due to a degraded dispersal infrastructure is no less important in explaining plant diversity losses than the more commonly accepted effect of eutrophication and associated niche-based processes. Our findings call for measures that aim to restore the dispersal infrastructure across entire regions and that go beyond current conservation practices. PMID:19016826

  12. 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

  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. 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…

  15. 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.

  16. The relative contribution of system failures and extreme behaviour in South Australian crashes.

    PubMed

    Wundersitz, Lisa; Baldock, Matthew; Raftery, Simon

    2014-12-01

    Within the road system, there are compliant road users who may make an error that leads to a crash, resulting in a 'system failure', and there are also road users who deliberately take risks and display dangerous or 'extreme' behaviours that lead to a crash. Crashes resulting from system failures can be addressed through improvements to road system design more readily than crashes resulting from extreme behaviours. The classification of crash causation in terms of system failures or extreme behaviour is important for determining the extent to which a Safe System approach (i.e. improvements to road system design to serve compliant road users) is capable of reducing the number of crashes. This study examined the relative contribution of system failures and extreme behaviour in South Australian crashes as identified from information in Coroner's investigation files and in-depth crash investigations conducted by the Centre for Automotive Safety Research (CASR). The analysis of 189 fatal crashes, 272 non-fatal metropolitan injury crashes and 181 non-fatal rural crashes indicated that very few non-fatal crashes (3% metropolitan, 9% rural) involved extreme behaviour by road users and, even in fatal crashes, the majority (54%) were the result of system failures. Fatal crashes resulting from system failures were more likely than those resulting from extreme behaviour to occur during the day, on weekdays, in rural areas and on roads with high speed limits. Findings from the current study suggest that improvements to the road transport system (i.e. forgiving road infrastructure, appropriate speed limits, and safe vehicle design) can be expected to be much more effective in reducing crashes than concentrating on preventing extreme behaviours. Such a strategy could reduce the incidence and severity of a large proportion of crashes in South Australia. PMID:25238295

  17. The relative contribution of system failures and extreme behaviour in South Australian crashes.

    PubMed

    Wundersitz, Lisa; Baldock, Matthew; Raftery, Simon

    2014-12-01

    Within the road system, there are compliant road users who may make an error that leads to a crash, resulting in a 'system failure', and there are also road users who deliberately take risks and display dangerous or 'extreme' behaviours that lead to a crash. Crashes resulting from system failures can be addressed through improvements to road system design more readily than crashes resulting from extreme behaviours. The classification of crash causation in terms of system failures or extreme behaviour is important for determining the extent to which a Safe System approach (i.e. improvements to road system design to serve compliant road users) is capable of reducing the number of crashes. This study examined the relative contribution of system failures and extreme behaviour in South Australian crashes as identified from information in Coroner's investigation files and in-depth crash investigations conducted by the Centre for Automotive Safety Research (CASR). The analysis of 189 fatal crashes, 272 non-fatal metropolitan injury crashes and 181 non-fatal rural crashes indicated that very few non-fatal crashes (3% metropolitan, 9% rural) involved extreme behaviour by road users and, even in fatal crashes, the majority (54%) were the result of system failures. Fatal crashes resulting from system failures were more likely than those resulting from extreme behaviour to occur during the day, on weekdays, in rural areas and on roads with high speed limits. Findings from the current study suggest that improvements to the road transport system (i.e. forgiving road infrastructure, appropriate speed limits, and safe vehicle design) can be expected to be much more effective in reducing crashes than concentrating on preventing extreme behaviours. Such a strategy could reduce the incidence and severity of a large proportion of crashes in South Australia.

  18. Autonomic contributions to empathy: evidence from patients with primary autonomic failure.

    PubMed

    Chauhan, Bina; Mathias, Christopher J; Critchley, Hugo D

    2008-06-01

    Empathy for the emotions of others may require simulatory engagement of corresponding autonomic arousal states. We tested the hypothesis that disruption of autonomic control impairs the ability to empathize emotionally with others. Fifteen patients with primary autonomic failure showed attenuated scores on the Mehrabian Balanced Emotional Empathy Scale (BEES), compared to both younger and older controls. This effect was not accounted for by age, gender, mood state or functional disability. These early observations provide preliminary evidence for a direct contribution of autonomic responsivity to the 'higher-order' social cognitive process of empathy, and may inform the dynamics of supportive care.

  19. 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

  20. 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.

  1. 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

  2. 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

  3. The contributions of dipeptidyl peptidase IV to inflammation in heart failure.

    PubMed

    de Almeida Salles, Thiago; Zogbi, Camila; de Lima, Thais Martins; de Godoi Carneiro, Camila; Garcez, Alexandre Teles; Barbeiro, Hermes Vieira; Antonio, Ednei Luiz; Dos Santos, Leonardo; da Costa Pereira, Alexandre; Tucci, Paulo José Ferreira; de Paula Faria, Daniele; Soriano, Francisco Garcia; Girardi, Adriana Castello Costa

    2016-06-01

    Circulating dipeptidyl peptidase IV (DPPIV) activity correlates with cardiac dysfunction in humans and experimental heart failure (HF) models. Similarly, inflammatory markers are associated with poorer outcomes in HF patients. However, the contributions of DPPIV to inflammation in HF remain elusive. Therefore, this study aimed to investigate whether the cardioprotective effects of DPPIV inhibition after myocardial injury are accompanied by reduced cardiac inflammation, whether circulating DPPIV activity correlates with the levels of systemic inflammatory markers in HF patients, and whether leukocytes and/or splenocytes may be one of the sources of circulating DPPIV in HF. Experimental HF was induced in male Wistar rats by left ventricular myocardial injury after radiofrequency catheter ablation. The rats were divided into three groups: sham, HF, and HF + DPPIV inhibitor (sitagliptin). Six weeks after surgery, cardiac function, perfusion and inflammatory status were evaluated. Sitagliptin treatment improved cardiac function and perfusion, reduced macrophage infiltration, and diminished the levels of inflammatory biomarkers including TNF-α, IL-1β, and CCL2. In HF patients, serum DPPIV activity correlated with CCL2, suggesting that leukocytes may be the source of circulating DPPIV in HF. Unexpectedly, DPPIV release was higher in splenocytes from HF rats and similar in HF circulating mononuclear cells compared with those from sham, suggesting an organ-specific modulation of DPPIV in HF. Collectively, our data provide new evidence that the cardioprotective effects of DPPIV inhibition in HF may be due to suppression of inflammatory cytokines. Moreover, they suggest that a vicious circle between DPPIV and inflammation may contribute to HF development and progression. PMID:27199127

  4. 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

  5. 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

  6. Tonic arterial chemoreceptor activity contributes to cardiac sympathetic activation in mild ovine heart failure.

    PubMed

    Xing, Daniel T; May, Clive N; Booth, Lindsea C; Ramchandra, Rohit

    2014-08-01

    Heart failure (HF) is associated with a large increase in cardiac sympathetic nerve activity (CSNA), which has detrimental effects on the heart and promotes arrhythmias and sudden death. There is increasing evidence that arterial chemoreceptor activation plays an important role in stimulating renal sympathetic nerve activity (RSNA) and muscle sympathetic nerve activity in HF. Given that sympathetic nerve activity to individual organs is differentially controlled, we investigated whether tonic arterial chemoreceptor activation contributes to the increased CSNA in HF. We recorded CSNA and RSNA in conscious normal sheep and in sheep with mild HF induced by rapid ventricular pacing (ejection fraction <40%). Tonic arterial chemoreceptor function was evaluated by supplementing room air with 100% intranasal oxygen (2-3 l min(-1)) for 20 min, thereby deactivating chemoreceptors. The effects of hyperoxia on resting levels and baroreflex control of heart rate, CSNA and RSNA were determined. In HF, chemoreceptor deactivation induced by hyperoxia significantly reduced CSNA [90 ± 2 versus 75 ± 5 bursts (100 heart beats)(-1), P < 0.05, n = 10; room air versus hyperoxia] and heart rate (96 ± 4 versus 85 ± 4 beats min(-1), P < 0.001, n = 12). There was no change in RSNA burst incidence [93 ± 4 versus 92 ± 4 bursts (100 heart beats)(-1), n = 7], although due to the bradycardia the RSNA burst frequency was decreased (90 ± 8 versus 77 ± 7 bursts min(-1), P < 0.001). In normal sheep, chemoreceptor deactivation reduced heart rate without a significant effect on CSNA or RSNA. In summary, deactivation of peripheral chemoreceptors during HF reduced the elevated levels of CSNA, indicating that tonic arterial chemoreceptor activation plays a critical role in stimulating the elevated CSNA in HF.

  7. Sulfonylurea Receptor 1 Contributes to the Astrocyte Swelling and Brain Edema in Acute Liver Failure

    PubMed Central

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

    2014-01-01

    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, non-selective cation channel (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 3-fold 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 co-treatment 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. PMID:24443056

  8. 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

  9. 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

  10. Contribution of Major Lifestyle Risk Factors for Incident Heart Failure in Older Adults

    PubMed Central

    Del Gobbo, Liana C.; Kalantarian, Shadi; Imamura, Fumiaki; Lemaitre, Rozenn; Siscovick, David S.; Psaty, Bruce M.; Mozaffarian, Dariush

    2015-01-01

    Objectives The goal of this study was to determine the relative contribution of major lifestyle factors on the development of heart failure (HF) in older adults. Background HF incurs high morbidity, mortality, and health care costs among adults ≥65 years of age, which is the most rapidly growing segment of the U.S. population. Methods We prospectively investigated separate and combined associations of lifestyle risk factors with incident HF (1,380 cases) over 21.5 years among 4,490 men and women in the Cardiovascular Health Study, which is a community-based cohort of older adults. Lifestyle factors included 4 dietary patterns (Alternative Healthy Eating Index, Dietary Approaches to Stop Hypertension, an American Heart Association 2020 dietary goals score, and a Biologic pattern, which was constructed using previous knowledge of cardiovascular disease dietary risk factors), 4 physical activity metrics (exercise intensity, walking pace, energy expended in leisure activity, and walking distance), alcohol intake, smoking, and obesity. Results No dietary pattern was associated with developing HF (p > 0.05). Walking pace and leisure activity were associated with a 26% and 22% lower risk of HF, respectively (pace >3 mph vs. <2 mph; hazard ratio [HR]: 0.74; 95% confidence interval [CI]: 0.63 to 0.86; leisure activity ≥845 kcal/week vs. <845 kcal/week; HR: 0.78; 95% CI: 0.69 to 0.87). Modest alcohol intake, maintaining a body mass index <30 kg/m2, and not smoking were also independently associated with a lower risk of HF. Participants with ≥4 healthy lifestyle factors had a 45% (HR: 0.55; 95% CI: 0.42 to 0.74) lower risk of HF. Heterogeneity by age, sex, cardiovascular disease, hypertension medication use, and diabetes was not observed. Conclusions Among older U.S. adults, physical activity, modest alcohol intake, avoiding obesity, and not smoking, but not dietary patterns, were associated with a lower risk of HF. PMID:26160366

  11. 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.

  12. Factors contributing to the hospitalization of patients with congestive heart failure.

    PubMed Central

    Chin, M H; Goldman, L

    1997-01-01

    OBJECTIVES: This study identifies acute precipitants of hospitalization and evaluates utilization of angiotension-converting enzyme inhibitors in patients admitted with congestive heart failure. METHODS: Cross-sectional chart-review study was done of 435 patients admitted nonelectively from February 1993 to February 1994 to an urban university hospital with a complaint of shortness of breath or fatigue and evidence of congestive heart failure. RESULTS: The most common identifiable abnormalities associated with clinical deterioration prior to admission were acute anginal chest pain (33%), respiratory infection (16%), uncontrolled hypertension with initial systolic blood pressure > or = 180 mm Hg (15%), atrial arrhythmia with heart rate > or = 120 (8%), and noncompliance with medications (15%) or diet (6%); in 34% of patients, no clear cause could be identified. After exclusion of those who were already on a different vasodilator or who had relative contraindications, 18 (32%) of the patients with ejection fractions < or = 0.35 measured prior to admission were not taking an angiotensin-converting enzyme inhibitor on presentation to the hospital. CONCLUSIONS: Interventions to improve compliance, the control of hypertension, and the appropriate use of angiotensin-converting enzyme inhibitors may prevent many hospitalizations of heart-failure patients. PMID:9146445

  13. 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.

  14. Abnormal Mitochondrial L-Arginine Transport Contributes to the Pathogenesis of Heart Failure and Rexoygenation Injury

    PubMed Central

    Byrne, Melissa; Joshi, Mandar; Horlock, Duncan; Lam, Nicholas T.; Gregorevic, Paul; McGee, Sean L.; Kaye, David M.

    2014-01-01

    Background Impaired mitochondrial function is fundamental feature of heart failure (HF) and myocardial ischemia. In addition to the effects of heightened oxidative stress, altered nitric oxide (NO) metabolism, generated by a mitochondrial NO synthase, has also been proposed to impact upon mitochondrial function. However, the mechanism responsible for arginine transport into mitochondria and the effect of HF on such a process is unknown. We therefore aimed to characterize mitochondrial L-arginine transport and to investigate the hypothesis that impaired mitochondrial L-arginine transport plays a key role in the pathogenesis of heart failure and myocardial injury. Methods and Results In mitochondria isolated from failing hearts (sheep rapid pacing model and mouse Mst1 transgenic model) we demonstrated a marked reduction in L-arginine uptake (p<0.05 and p<0.01 respectively) and expression of the principal L-arginine transporter, CAT-1 (p<0.001, p<0.01) compared to controls. This was accompanied by significantly lower NO production and higher 3-nitrotyrosine levels (both p<0.05). The role of mitochondrial L-arginine transport in modulating cardiac stress responses was examined in cardiomyocytes with mitochondrial specific overexpression of CAT-1 (mtCAT1) exposed to hypoxia-reoxygenation stress. mtCAT1 cardiomyocytes had significantly improved mitochondrial membrane potential, respiration and ATP turnover together with significantly decreased reactive oxygen species production and cell death following mitochondrial stress. Conclusion These data provide new insights into the role of L-arginine transport in mitochondrial biology and cardiovascular disease. Augmentation of mitochondrial L-arginine availability may be a novel therapeutic strategy for myocardial disorders involving mitochondrial stress such as heart failure and reperfusion injury. PMID:25111602

  15. Contribution of peripheral chemoreceptors to ventilation and the effects of their suppression on exercise tolerance in chronic heart failure.

    PubMed Central

    Chua, T. P.; Ponikowski, P. P.; Harrington, D.; Chambers, J.; Coats, A. J.

    1996-01-01

    OBJECTIVES: To assess the contribution of peripheral chemoreceptors to ventilation and the effects of continuous inspired oxygen on exercise tolerance in chronic heart failure patients. The role of peripheral chemoreceptors in mediating hyperpnoea in chronic heart failure is unknown. Hyperoxia is known to suppress the peripheral chemoreceptor drive. The magnitude of decrease in ventilation with transient inhalations of oxygen thus provides a measure of the contribution of the peripheral chemoreceptors to ventilation. SETTING: Tertiary specialist hospital. SUBJECTS AND METHODS: Three breaths of 100% oxygen were given at rest and also during cycle ergometry at 25 W to 8 healthy controls (age 52.0 (4.7) (SEM) years) and 13 patients with chronic heart failure (age 60.5 (2.1) years (P = NS); radionuclide left ventricular ejection fraction 25.5 (4.3)%). The peripheral chemoreceptor sensitivity was also measured by assessing the ventilatory response to hypoxia using transient inhalations of pure nitrogen. Another group of 12 patients with chronic heart failure (age 65.5 (1.5) years; left ventricular ejection fraction 21.3 (3.0)%) underwent treadmill exercise testing on 2 occasions, breathing air or 100% oxygen in a randomised single-blind manner, to examine the effects of continuous inspired oxygen on exercise tolerance. RESULTS: The reduction in ventilation with transient hyperoxia was 18.1 (2.9)% v 17.9 (2.6)% (P = NS) at rest and 20.4 (2.8)% v 21.0 (1.6)% (P = NS) during cycle ergometry, for controls and patients respectively. The hypoxic chemosensitivity was higher in patients (0.232 (0.022) v 0.572 (0.082) 1/min/%SaO2; P = 0.002). Continuous inspired oxygen increased exercise time (517 (31) v 455 (27) seconds; P = 0.003), and a trend towards a reduction in the ventilatory response to exercise, characterised by the regression slope relating ventilation to carbon dioxide output, was evident (31.27 (2.60) v 34.19 (2.35); P = 0.08). CONCLUSIONS: Despite an increased

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

    PubMed

    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 Ca(2+) 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 Ca(2+) 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 Ca(2+) sparks, reduces Ca(2+) transient variability, and hastens the decay of Ca(2+) 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 Ca(2+) rise exclusively in the proximity of T-tubules that regularly conduct the action potential. The delayed Ca(2+) 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

  17. 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

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

    PubMed

    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

    2015-12-14

    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.

  19. 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.

  20. 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. PMID:25407618

  1. Angioscopic findings before and after thrombus-related drug-eluting stent failure.

    PubMed

    Kotani, Jun-ichi; Nanto, Shinsuke; Ueda, Yasunori; Uematsu, Masaaki; Nishino, Masami; Miyazaki, Shunichi; Yasaka, Yoshinori; Yasuda, Satoshi; Mizuno, Kyoichi

    2015-07-01

    Drug-eluting stent (DES) failure and conditions thereafter remain issues of concern despite generational advancements in DES technology. Registry data and pathological investigations have shown a variety of causes of late stent thrombosis and very late stent thrombosis. On the other hand, clinical imaging including serial studies can provide information on the conditions during the event, the previous status of the lesion, and the healing process after stent implantation. Therefore we investigated thrombus-related DES failure using coronary angioscopy (CAS), which is a robust tool for thrombus assessment. Five out of 8 thrombotic DES failures were documented during urgent repeat percutaneous coronary intervention (repeat PCI). Four patients underwent CAS before the event, and 5 patients were followed using CAS after repeat PCI for DES failure. Among these cases, there were data before and after the event in 4 patients, which highlighted various patterns of healing after repeat PCI for thrombus-related DES failure, including erosion and yellow plaque underneath the DES. The cause of thrombus formation in this series was delayed healing process, but other possible triggers included restenosis, insufficient DAPT duration, neoatherosclerosis, and vasospasm. In addition to these findings being consistent with previous segmental postmortem studies, invasive imaging modalities can provide data on more than just the event itself, such as sequential comparison and lesion features of the survivor. Accumulation of this knowledge would contribute to generating new hypothesis in the future. PMID:25666526

  2. 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.

  3. 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

  4. 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

  5. Étude de la contribution de la diffusion simple et multiple à l'amplitude des atomes voisins du silicium dans SiO{2} : application à un granulat soumis à la réaction alcali-silice

    NASA Astrophysics Data System (ADS)

    Boinski, F.; Khouchaf, L.; Verstraete, J.; Tuilier, M. H.

    2004-11-01

    Les amplitudes des différentes distributions lointaines de la transformée de Fourier d'un spectre EXAFS contiennent des informations précieuses pour la caractérisation de l'ordre local autour d'un atome donné. Ces informations sont souvent nécessaires pour la proposition de modèles. Or souvent dans cette zone, les distances inter atomiques correspondent à des libres parcours moyens du photoélectron assez importants. La contribution due à la diffusion multiple perturbe le signal propre de la diffusion simple des atomes diffuseurs. Afin de mieux évaluer l'influence de la diffusion multiple dans nos échantillons constitués de granulats à base de SiO{2} attaqués par la réaction alcali-silice, nous avons calculé les différents parcours de diffusion simple et multiple dans ce composé. Les calculs montrent que lorsque la contribution de la diffusion multiple n'est pas atténuée, l'exploitation des voisins lointains est difficile voir impossible. La modélisation des spectres TF expérimentaux a pu être réalisée uniquement en négligeant la contribution de la diffusion multiple. Ce résultat va nous permettre l'exploitation des voisins lointains en particulier les atomes silicium dans le granulat brut et après dégradation en se basant sur le formalisme de la diffusion simple.

  6. Contribution a la caracterisation des betons endommages par des methodes de l'acoustique non lineaire. Application a la reaction alcalis-silice

    NASA Astrophysics Data System (ADS)

    Kodjo, Apedovi

    The aim of this thesis is to contribute to the non-destructive characterization of concrete materials damaged by alkali-silica reaction (ASR). For this purpose, some nonlinear characterization techniques have been developed, as well as a nonlinear resonance test device. In order to optimize the sensitivity of the test device, the excitation module and signal processing have been improved. The nonlinear tests were conducted on seven samples of concrete damaged by ASR, three samples of concrete damaged by heat, three concrete samples damaged mechanically and three sound concrete samples. Since, nonlinear behaviour of the material is often attribute to its micro-defects hysteretic behaviour, it was shown at first that concrete damaged by ASR exhibits an hysteresis behaviour. To conduct this study, an acoustoelastic test was set, and then nonlinear resonance test device was used for characterizing sound concrete and concrete damaged by ASR. It was shown that the nonlinear technique can be used for characterizing the material without knowing its initial state, and also for detecting early damage in the reactive material. Studies were also carried out on the effect of moisture regarding the nonlinear parameters; they allowed understanding the low values of nonlinear parameters measured on concrete samples that were kept in high moisture conditions. In order to find a specific characteristic of damage caused by ASR, the viscosity of ASR gel was used. An approach, based on static creep analysis, performed on the material, while applying the nonlinear resonance technique. The spring-damping model of Maxwell was used for the interpretation of the results. Then, the creep time was analysed on samples damaged by ASR. It appears that the ASR gel increases the creep time. Finally, the limitations of the nonlinear resonance technique for in situ application have been explained and a new applicable nonlinear technique was initiated. This technique use an external source such as a

  7. "Blood failure" time to view blood as an organ: how oxygen debt contributes to blood failure and its implications for remote damage control resuscitation.

    PubMed

    Bjerkvig, Christopher K; Strandenes, Geir; Eliassen, Håkon S; Spinella, Philip C; Fosse, Theodor K; Cap, Andrew P; Ward, Kevin R

    2016-04-01

    Hemorrhagic shock is both a local and systemic disorder. In the context of systemic effects, blood loss may lead to levels of reduced oxygen delivery (DO2 ) sufficient to cause tissue ischemia. Similar to other physiologic debts such as sleep, it is not possible to incur a significant oxygen debt and suffer no consequences for lack of timely repayment. While the linkage between oxygen debt and traditional organ failure (renal, hepatic, lung, and circulation) has been long recognized, we should consider failure in two additional linked and very dynamic organ systems, the endothelium and blood. These systems are very sensitive to oxygen debt and at risk for failing, having further implications on all other organ systems. The degree of damage to the endothelium is largely modulated by the degree of oxygen debt. Thus hypoperfusion is believed to begin a cascade of events leading to acute traumatic coagulopathy (ATC). This combination of oxygen debt driven endothelial damage and ATC might be considered collectively as "blood failure" due to the highly connected networks between these drivers. This article presents the implications of oxygen debt for remote damage control resuscitation strategies, such as permissive hypotension and hemostatic resuscitation. We review the impact of whole blood resuscitation and red blood cell efficacy in mitigation of oxygen debt. At last, this article recognizes the need for simple and durable, lightweight equipment that can detect the adequacy of tissue DO2 and thus patient needs for resuscitative care. Point-of-care lactate measuring may be a predictive tool for identifying high-risk trauma patients and occult shock because it provides information beyond that of vital signs and mechanism of injury as it may help predict the level of oxygen debt accumulation and need for resuscitation. Serial measurements may also be valuable as a tool in guiding resuscitative efforts. PMID:27100755

  8. 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

  9. 26 CFR 54.4980G-3 - Failure of employer to make comparable health savings account contributions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... distributions under section 731. However, if a partnership contributes to the HSAs of any employee who is not a... contribution to each of A's and B's HSAs which are treated as section 731 distributions to A and B; (B) A $300... contributions to A's and B's HSAs are section 731 distributions, which are treated as cash...

  10. 26 CFR 54.4980G-3 - Failure of employer to make comparable health savings account contributions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... distributions under section 731. However, if a partnership contributes to the HSAs of any employee who is not a... contribution to each of A's and B's HSAs which are treated as section 731 distributions to A and B; (B) A $300... contributions to A's and B's HSAs are section 731 distributions, which are treated as cash...

  11. 26 CFR 54.4980G-3 - Failure of employer to make comparable health savings account contributions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... distributions under section 731. However, if a partnership contributes to the HSAs of any employee who is not a... contribution to each of A's and B's HSAs which are treated as section 731 distributions to A and B; (B) A $300... contributions to A's and B's HSAs are section 731 distributions, which are treated as cash...

  12. 26 CFR 54.4980G-3 - Failure of employer to make comparable health savings account contributions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... distributions under section 731. However, if a partnership contributes to the HSAs of any employee who is not a... contribution to each of A's and B's HSAs which are treated as section 731 distributions to A and B; (B) A $300... contributions to A's and B's HSAs are section 731 distributions, which are treated as cash...

  13. 26 CFR 54.4980G-3 - Failure of employer to make comparable health savings account contributions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... distributions under section 731. However, if a partnership contributes to the HSAs of any employee who is not a... contribution to each of A's and B's HSAs which are treated as section 731 distributions to A and B; (B) A $300... contributions to A's and B's HSAs are section 731 distributions, which are treated as cash...

  14. Suppressed Production of Soluble Fms-Like Tyrosine Kinase-1 Contributes to Myocardial Remodeling and Heart Failure.

    PubMed

    Seno, Ayako; Takeda, Yukiji; Matsui, Masaru; Okuda, Aya; Nakano, Tomoya; Nakada, Yasuki; Kumazawa, Takuya; Nakagawa, Hitoshi; Nishida, Taku; Onoue, Kenji; Somekawa, Satoshi; Watanabe, Makoto; Kawata, Hiroyuki; Kawakami, Rika; Okura, Hiroyuki; Uemura, Shiro; Saito, Yoshihiko

    2016-09-01

    Soluble fms-like tyrosine kinase-1 (sFlt-1), an endogenous inhibitor of vascular endothelial growth factor and placental growth factor, is involved in the pathogenesis of cardiovascular disease. However, the significance of sFlt-1 in heart failure has not been fully elucidated. We found that sFlt-1 is decreased in renal failure and serves as a key molecule in atherosclerosis. In this study, we aimed to investigate the role of the decreased sFlt-1 production in heart failure, using sFlt-1 knockout mice. sFlt-1 knockout mice and wild-type mice were subjected to transverse aortic constriction and evaluated after 7 days. The sFlt-1 knockout mice had significantly higher mortality (52% versus 15%; P=0.0002) attributable to heart failure and showed greater cardiac hypertrophy (heart weight to body weight ratio, 8.95±0.45 mg/g in sFlt-1 knockout mice versus 6.60±0.32 mg/g in wild-type mice; P<0.0001) and cardiac dysfunction, which was accompanied by a significant increase in macrophage infiltration and cardiac fibrosis, than wild-type mice after transverse aortic constriction. An anti-placental growth factor-neutralizing antibody prevented pressure overload-induced cardiac hypertrophy, fibrosis, and cardiac dysfunction. Moreover, monocyte chemoattractant protein-1 expression was significantly increased in the hypertrophied hearts of sFlt-1 knockout mice compared with wild-type mice. Monocyte chemoattractant protein-1 inhibition with neutralizing antibody ameliorated maladaptive cardiac remodeling in sFlt-1 knockout mice after transverse aortic constriction. In conclusion, decreased sFlt-1 production plays a key role in the aggravation of cardiac hypertrophy and heart failure through upregulation of monocyte chemoattractant protein-1 expression in pressure-overloaded heart.

  15. 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

  16. 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.

  17. Did submarine mass failures significantly contribute to the extreme runup of the Tohoku-oki 2011 tsunami in Sanriku

    NASA Astrophysics Data System (ADS)

    Grilli, S. T.; Harris, J. C.; Tappin, D. R.; Masterlark, T.; Kirby, J. T.; Shi, F.; Ma, G.

    2012-12-01

    The devastating coastal impact of the 2011 Tohoku-oki tsunami (40+ m runup along the Sanriku coast) cannot at present be fully explained from a co-seismic source alone. In earlier work, the authors developed and used in tsunami simulations a new co-seismic source based on a detailed three-dimensional Finite Element Model (FEM) of the heterogeneous subduction zone, with geodetic data assimilation, and showed that it better explains long wave features of the tsunami, measured at deep water (DART) and nearshore (GPS) buoys, than any of the other proposed sources that did not assimilate tsunami observations. Simulations based on any of these coseismic sources, however, could not reproduce the large higher frequency waves (order 3 min. period) recorded at GPS buoys off of the Sanriku Coast, which were shown to be responsible for the largest tsunami runup heights. By contrast, sources solely based on inverting tsunami observation at GPS and DART buoys indicated that shorter scale seabed failures should have occurred north of the main rupture, with a 100 sec. time delay with respect to the main rupture. Travel time/ray tracing analyses performed by the authors on the 3 min. period waves observed at the Iwate buoys confirm this finding and identify an area around 39.5 deg. N as the origin of these waves. A comparison of pre- and post-tsunami seafloor surveys in the area further confirms that vertical seafloor motions as large as 40 m may have occurred as a result of the earthquake, that match the footprint of a large rotational submarine mass failure (SMF; i.e., a slump). Slope stability analyses finally indicate that this area would also have ben the likeliest to fail under seismic loading. Accordingly, we model the tsunami generated from the combination of: (i) our earlier FEM coseimsic source; and (ii) an additional tsunami source from a shorter scale SMF triggered north of the main rupture with a 2' time delay. We show that the multi-source tsunami agrees well with all

  18. 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

  19. 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.

  20. 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 ...

  1. 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

  2. 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

  3. 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)

  4. 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.

  5. 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…

  6. Kidney Failure

    MedlinePlus

    ... if You Have Kidney Disease Kidney Failure Expand Dialysis Kidney Transplant Preparing for Kidney Failure Treatment Choosing Not to Treat with Dialysis or Transplant Paying for Kidney Failure Treatment Contact ...

  7. 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.

  8. Notable Australian contributions to the management of ventilatory failure of acute poliomyelitis: with special reference to the Both respirator and Dr. John A. Forbes.

    PubMed

    Trubuhovich, Ronald V

    2006-12-01

    When Australia's 1937 epidemic of poliomyelitis created an urgent need for extra ventilating machines to compensate for respiratory paralysis, Edward Both, an innovative Adelaide biomedical engineer, invented a wooden-cabinet respirator capable of being made relatively quickly in sufficient quantity. His device, here called "the Both", alleviated the problem at Adelaide's Northfield Infectious Diseases Hospital and others, and in late 1938 was introduced into England when Both was visiting there. Appreciating its merits, Lord Nuffield financed assembly-line production at the Morris motor works in Cowley, Oxford. Then, through the Nuffield Department of Anaesthetics in Oxford's Radcliffe Infirmary, he had the Both distributed Commonwealth-wide, as a gift for treating ventilatory failure in polio - especially in children. For the 1937 epidemic in Victoria, and to the design of Melbourne University's Professor of Engineering, Aubrey Burstall, nearly 200 of another wooden-cabinet respirator were ultimately built. Some were installed at the Acute Respiratory Unit of the Infectious Diseases Hospital at Fairfield, then others "all over Australia". However, by the early 1950s, the Both had replaced Fairfield Hospital's "Burstall", which had functioned as Victoria's favoured respirator since 1937. Dr John Forbes at Fairfield became the foremost Australian clinician for expertise with the Both. Before the advent of intermittent positive pressure ventilation, the Both's usefulness had seen it tried for ventilatory failure in some non-polio conditions, but uptake of that application was limited. Nonetheless, Nuffield's philanthropy with the (Nuffield-)Both ultimately furthered progress along the 20th century pathway to intensive care medicine.

  9. 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' ...

  10. BMP15 c.-9C>G promoter sequence variant may contribute to the cause of non-syndromic premature ovarian failure.

    PubMed

    Fonseca, Dora Janeth; Ortega-Recalde, Oscar; Esteban-Perez, Clara; Moreno-Ortiz, Harold; Patiño, Liliana Catherine; Bermúdez, Olga María; Ortiz, Angela María; Restrepo, Carlos M; Lucena, Elkin; Laissue, Paul

    2014-11-01

    BMP15 has drawn particular attention in the pathophysiology of reproduction, as its mutations in mammalian species have been related to different reproductive phenotypes. In humans, BMP15 coding regions have been sequenced in large panels of women with premature ovarian failure (POF), but only some mutations have been definitely validated as causing the phenotype. A functional association between the BMP15 c.-9C>G promoter polymorphism and cause of POF have been reported. The aim of this study was to determine the potential functional effect of this sequence variant on specific BMP15 promoter transactivation disturbances. Bioinformatics was used to identify transcription factor binding sites located on the promoter region of BMP15. Reverse transcription polymerase chain reaction was used to study specific gene expression in ovarian tissue. Luciferase reporter assays were used to establish transactivation disturbances caused by the BMP15 c.-9C>G variant. The c.-9C>G variant was found to modify the PITX1 transcription factor binding site. PITX1 and BMP15 co-expressed in human and mouse ovarian tissue, and PITX1 transactivated both BMP15 promoter versions (-9C and -9G). It was found that the BMP15 c.-9G allele was related to BMP15 increased transcription, supporting c.-9C>G as a causal agent of POF.

  11. 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.

  12. Interleukin-10 Contributes to Therapeutic Effect of Mesenchymal Stem Cells for Acute Liver Failure via Signal Transducer and Activator of Transcription 3 Signaling Pathway

    PubMed Central

    Ma, Hu-Cheng; Wang, Xin; Wu, Min-Na; Zhao, Xin; Yuan, Xian-Wen; Shi, Xiao-Lei

    2016-01-01

    Background: Mesenchymal stem cells (MSCs) transplantation has been proven to have therapeutic potential for acute liver failure (ALF). However, the mechanism remains controversial. Recently, modulation of inflammation by MSCs has been regarded as a crucial mechanism. The aim of the present study was to explore the soluble cytokines secreted by MSCs and their therapeutic effects in ALF. Methods: MSCs isolated from Sprague-Dawley rats were identified by fluorescence-activated cell sorting analysis. Conditioned medium derived from MSCs (MSCs-CM) was collected and analyzed by a cytokine microarray. MSCs and MSCs-CM were transplanted into rats with D-galactosamine-induced ALF. Liver function, survival rate, histology, and inflammatory factors were determined. Exogenous recombinant rat interleukin (IL)-10, anti-rat IL-10 antibody, and AG490 (signal transducer and activator of transcription 3 [STAT3] signaling pathway inhibitor) were administered to explore the therapeutic mechanism of MSCs-CM. Statistical analysis was performed with SPSS version 19.0, and all data were analyzed by the independent-sample t-test. Results: There are statistical differences of the survival curve between ALF+MSCs group and ALF+Dulbecco's modified Eagle's medium (DMEM) group, as well as ALF+MSCs-CM group and ALF+DMEM group (all P < 0.05). Serum alanine aminotransferase (ALT) level in the ALF+MSCs and ALF+MSCs-CM groups was lower than that in the ALF+DMEM group (865.53±52.80 vs. 1709.75±372.12 U/L and 964.72±414.59 vs. 1709.75±372.12 U/L, respectively, all P < 0.05); meanwhile, serum aspartate aminotransferase (AST) level in the ALF+MSCs and ALF+MSCs-CM groups was lower than that in the ALF+DMEM group (2440.83±511.94 vs. 4234.35±807.30 U/L and 2739.83±587.33 vs. 4234.35±807.30 U/L, respectively, all P < 0.05). Furthermore, MSCs or MSCs-CM treatment significantly reduced serum interferon-γ (IFN-γ), IL-1β, IL-6 levels and increased serum IL-10 level compared with DMEM (all P < 0

  13. 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

  14. Testicular failure

    MedlinePlus

    ... LH . Your doctor may also order a semen analysis to examine the number of healthy sperm you are producing. Sometimes, an ultrasound of the testes will be ordered. Testicular failure and low testosterone level may be hard to ...

  15. 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

  16. Pathophysiology of Heart Failure.

    PubMed

    Tanai, Edit; Frantz, Stefan

    2015-12-15

    Heart failure is considered an epidemic disease in the modern world affecting approximately 1% to 2% of adult population. It presents a multifactorial, systemic disease, in which--after cardiac injury--structural, neurohumoral, cellular, and molecular mechanisms are activated and act as a network to maintain physiological functioning. These coordinated, complex processes lead to excessive volume overload, increased sympathetic activity, circulation redistribution, and result in different, parallel developing clinical signs and symptoms. These signs and symptoms sum up to an unspecific clinical picture; thus invasive and noninvasive diagnostic tools are used to get an accurate diagnosis and to specify the underlying cause. The most important, outcome determining factor in heart failure is its constant progression. Constant optimizing of pharmatherapeutical regimes, novel targets, and fine regulation of these processes try to keep these compensatory mechanisms in a physiological range. Beside pharmacological therapy, interventional and surgical therapy options give new chances in the management of heart failure. For the optimization and establishment of these and novel therapeutical approaches, complete and comprehensive understanding of the underlying mechanisms is essentially needed. Besides diagnosis and treatment, efforts should be made for better prevention in heart failure by treatment of risk factors, or identifying and following risk groups. This summary of the pathophysiology of heart failure tries to give a compact overview of basic mechanisms and of the novel unfolding, progressive theory of heart failure to contribute to a more comprehensive knowledge of the disease.

  17. Pathophysiology of Heart Failure.

    PubMed

    Tanai, Edit; Frantz, Stefan

    2015-01-01

    Heart failure is considered an epidemic disease in the modern world affecting approximately 1% to 2% of adult population. It presents a multifactorial, systemic disease, in which--after cardiac injury--structural, neurohumoral, cellular, and molecular mechanisms are activated and act as a network to maintain physiological functioning. These coordinated, complex processes lead to excessive volume overload, increased sympathetic activity, circulation redistribution, and result in different, parallel developing clinical signs and symptoms. These signs and symptoms sum up to an unspecific clinical picture; thus invasive and noninvasive diagnostic tools are used to get an accurate diagnosis and to specify the underlying cause. The most important, outcome determining factor in heart failure is its constant progression. Constant optimizing of pharmatherapeutical regimes, novel targets, and fine regulation of these processes try to keep these compensatory mechanisms in a physiological range. Beside pharmacological therapy, interventional and surgical therapy options give new chances in the management of heart failure. For the optimization and establishment of these and novel therapeutical approaches, complete and comprehensive understanding of the underlying mechanisms is essentially needed. Besides diagnosis and treatment, efforts should be made for better prevention in heart failure by treatment of risk factors, or identifying and following risk groups. This summary of the pathophysiology of heart failure tries to give a compact overview of basic mechanisms and of the novel unfolding, progressive theory of heart failure to contribute to a more comprehensive knowledge of the disease. PMID:26756631

  18. Heart failure.

    PubMed

    2014-12-15

    Essential facts Heart failure affects about 900,000 people in the UK. The condition can affect people of all ages, but it is more common in older people, with more than half of all patients over the age of 75. It is caused by the heart failing to pump enough blood around the body at the right pressure, usually because the heart muscle has become too weak or stiff to work properly. Acute heart failure, which occurs when symptoms develop quickly, is the leading cause of hospital admission in people over 65. PMID:25492766

  19. 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.

  20. 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.

  1. Heart Failure

    MedlinePlus

    ... of breath Common causes of heart failure are coronary artery disease, high blood pressure and diabetes. It is more common in people who are 65 years old or older, African Americans, people who are ... treatments fail. NIH: National Heart, Lung, and Blood Institute

  2. 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.

  3. Treatment failure in humanistic and experiential psychotherapy.

    PubMed

    Watson, Jeanne C

    2011-11-01

    In this article, treatment failure in humanistic experiential psychotherapy is defined and explored. I outline several markers that indicate when treatment is not going well. Factors that contribute to failure include client factors, for example, emotional processing capacities, shame, and impoverished narratives, as well as therapist factors including lack of empathic attunement and inflexibility. Treatment failure is illuminated with a case example drawn from humanistic/experiential psychotherapy, and clinical strategies for dealing with failures are recommended.

  4. 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.

  5. 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

  6. Heart failure in North America.

    PubMed

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

    2013-05-01

    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

  7. 32-Bit-Wide Memory Tolerates Failures

    NASA Technical Reports Server (NTRS)

    Buskirk, Glenn A.

    1990-01-01

    Electronic memory system of 32-bit words corrects bit errors caused by some common type of failures - even failure of entire 4-bit-wide random-access-memory (RAM) chip. Detects failure of two such chips, so user warned that ouput of memory may contain errors. Includes eight 4-bit-wide DRAM's configured so each bit of each DRAM assigned to different one of four parallel 8-bit words. Each DRAM contributes only 1 bit to each 8-bit word.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Interprétation hydrogéologique de l'aquifère des bassins sud-rifains (Maroc) : apport de la sismique réflexionHydrogeological interpretation of the southern Rifean basins aquifer (Morocco): seismic reflexion contribution

    NASA Astrophysics Data System (ADS)

    Zouhri, Lahcen; Gorini, Christian; Lamouroux, Christian; Vachard, Daniel; Dakki, Mohammed

    2003-03-01

    The aquifer of the Rharb Basin is constituted by heterogeneous material. The seismic reflexion interpretation carried out in this area, highlighted a permeable device compartmentalized in raised and subsided blocks. Depressions identified in the northern and southernmost zones are characterized by Plio-Quaternary fillings that are favourable to the hydrogeological exploitation. Two mechanisms contribute to structure the Plio-Quaternary aquifer: the Hercynian reactivation in the southernmost part, and the gravitational mechanism of the Pre-Rifean nappe. The groundwater flow and the aquifer thickening are controlled by this reactivation.

  13. 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 ...

  14. 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 ...

  15. 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 ...

  16. 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.

  17. 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.

  18. Advanced Heart Failure

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Advanced Heart Failure Updated:Oct 8,2015 When heart failure (HF) ... content was last reviewed on 04/06/2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  19. 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.

  20. Mesh convergence differences based on failure mechanisms

    SciTech Connect

    Pilat, K.R.; Revelli, V.D.

    1994-04-01

    Material properties affect the deformation and failure modes in structural parts. When performing finite element analyses to compare response for different materials, different levels of mesh discretization may be necessary for each analyses because the failure mode changes, even through the part geometry and loading remain the same. Take, for example, strain localization, a material dependent phenomenon. When localization occurs, the mesh needs to be much finer to capture the steep strain gradients in the region of localization than in a case where localization does not occur. Although this requirement is almost intuitive once stated, it is often not used in practice because the effects are less pronounced when failure is not present, and also because failure modes are difficult to anticipate. The lack of availability of constitutive models for failure prediction is also a contributing factor. This paper describes a recent study regarding the effect of mesh refinement on failure prediction in a part modeled with two different materials.

  1. 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.

  2. 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. PMID:27034277

  3. 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.

  4. 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.

  5. Faster clearance of omeprazole in rats with acute renal failure induced by uranyl nitrate: contribution of increased expression of hepatic cytochrome P450 (CYP) 3A1 and intestinal CYP1A and 3A subfamilies.

    PubMed

    Lee, Dae Y; Jung, Young S; Shin, Hyun S; Lee, Inchul; Kim, Young C; Lee, Myung G

    2008-07-01

    It has been reported that omeprazole is mainly metabolized via hepatic cytochrome P450 (CYP) 1A1/2, CYP2D1 and CYP3A1/2 in male Sprague-Dawley rats, and the expression of hepatic CYP3A1 is increased in male Sprague-Dawley rats with acute renal failure induced by uranyl nitrate (U-ARF rats). Thus, the metabolism of omeprazole would be expected to increase in U-ARF rats. After intravenous administration of omeprazole (20 mgkg(-1)) to U-ARF rats, the area under the plasma concentration-time curve from time zero to infinity (AUC) was significantly reduced (371 vs 494 microg min mL(-1)), possibly due to the significantly faster non-renal clearance (56.6 vs 41.2 mL min(-1) kg(-1)) compared with control rats. This could have been due to increased expression of hepatic CYP3A1 in U-ARF rats. After oral administration of omeprazole (40 mgkg(-1)) to U-ARF rats, the AUC was also significantly reduced (89.3 vs 235 microg min mL(-1)) compared with control rats. The AUC difference after oral administration (62.0% decrease) was greater than that after intravenous administration (24.9% decrease). This may have been primarily due to increased intestinal metabolism of omeprazole caused by increased expression of intestinal CYP1A and 3A subfamilies in U-ARF rats, in addition to increased hepatic metabolism.

  6. 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.

  7. Contraceptive failure in China.

    PubMed

    Wang, Duolao

    2002-09-01

    This study examines patterns and differentials of contraceptive failure rates by method and characteristics of users, using the Chinese Two-per-Thousand Fertility Survey data. The results show that contraceptive failure rates for modern methods including sterilization are some of the highest in the world. The first year failure rates are 4.2% for male sterilization, 0.7% for female sterilization, 10.3% for IUD, 14.5% for pill, and 19.0% for condom. There are also some differentials in contraceptive failure rates by users' sociodemographic and fertility characteristics. Contraceptive failure rate declines with women's age for all reversible methods. Rural women have higher sterilization, IUD, and condom contraceptive failure rates than urban women. Women with two or more children have a higher failure rate for sterilization methods but have lower failure rates for other methods.

  8. 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

  9. In Support of Failure

    ERIC Educational Resources Information Center

    Carr, Allison

    2013-01-01

    In this essay, I propose a concerted effort to begin devising a theory and pedagogy of failure. I review the discourse of failure in Western culture as well as in composition pedagogy, ultimately suggesting that failure is not simply a judgement or indication of rank but is a relational, affect-bearing concept with tremendous relevance to…

  10. 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)

  11. 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

  12. 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.

  13. 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.

  14. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. 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.

  17. 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.

  18. Common Variants for Heart Failure

    PubMed Central

    Shen, Shutong; Tao, Lichan; Wang, Xiuzhi; Kong, Xiangqing; Li, Xinli

    2015-01-01

    Heart failure (HF) is a common disease with high morbidity and mortality; however, none of the drugs available are now entirely optimal for the treatment of HF. In addition to various clinical diseases and environment influences, genetic factors also contribute to the development and progression of HF. Identifying the common variants for HF by genome-wide association studies will facilitate the understanding of pathophysiological mechanisms underlying HF. This review summarizes the recently identified common variants for HF risk and outcome and discusses their implications for the clinic therapy. PMID:26085806

  19. 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.

  20. 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. PMID:26443889

  1. 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

  2. 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.

  3. Immune mediated liver failure

    PubMed Central

    Wang, Xiaojing; Ning, Qin

    2014-01-01

    Liver failure is a clinical syndrome of various etiologies, manifesting as jaundice, encephalopathy, coagulopathy and circulatory dysfunction, which result in subsequent multiorgan failure. Clinically, liver failure is classified into four categories: acute, subacute, acute-on-chronic and chronic liver failure. Massive hepatocyte death is considered to be the core event in the development of liver failure, which occurs when the extent of hepatocyte death is beyond the liver regenerative capacity. Direct damage and immune-mediated liver injury are two major factors involved in this process. Increasing evidence has suggested the essential role of immune-mediated liver injury in the pathogenesis of liver failure. Here, we review the evolved concepts concerning the mechanisms of immune-mediated liver injury in liver failure from human and animal studies. Both innate and adaptive immunity, especially the interaction of various immune cells and molecules as well as death receptor signaling system are discussed. In addition, we highlight the concept of “immune coagulation”, which has been shown to be related to the disease progression and liver injury exacerbation in HBV related acute-on-chronic liver failure. PMID:26417328

  4. 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).

  5. Generalized energy failure criterion.

    PubMed

    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

  6. 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

  7. 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

  8. 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…

  9. Heart failure in African Americans: disparities can be overcome.

    PubMed

    Sharma, Alok; Colvin-Adams, Monica; Yancy, Clyde W

    2014-05-01

    African Americans are disproportionately affected by heart failure, with a high prevalence at an early age. Hypertension, diabetes, obesity, and chronic kidney disease are all common in African Americans and all predispose to heart failure. Neurohormonal imbalances, endothelial dysfunction, genetic polymorphisms, and socioeconomic factors also contribute. In general, the same evidence-based treatment guidelines that apply to white patients with heart failure also apply to African Americans. However, the combination of hydralazine and isosorbide dinitrate is advised specifically for African Americans.

  10. 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.

  11. 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.

  12. Progressive failure of structures

    NASA Technical Reports Server (NTRS)

    Khozeimeh, K.; Toridis, G. T. G.; Zanganeh, S. E.

    1978-01-01

    A procedure is presented for determining the nonlinear behavior of structures subjected to extreme loading and the possibility of development of potential for progressive failure. The methodology takes into account the effect of both material and geometric nonlinearities. At a given stage of analysis, the individual components of the structure are checked against predetermined failure criteria. Subsequently, the failing components are removed and the modified structure is analyzed for overall failure. Examples, obtained from a computer program based on the proposed procedure, showing the applicability of the method are presented.

  13. 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.

  14. Failure of Viral Shells

    NASA Astrophysics Data System (ADS)

    Klug, William S.; Bruinsma, Robijn F.; Michel, Jean-Philippe; Knobler, Charles M.; Ivanovska, Irena L.; Schmidt, Christoph F.; Wuite, Gijs J. L.

    2006-12-01

    We report a combined theoretical and experimental study of the structural failure of viral shells under mechanical stress. We find that discontinuities in the force-indentation curve associated with failure should appear when the so-called Föppl von Kármán (FvK) number exceeds a critical value. A nanoindentation study of a viral shell subject to a soft-mode instability, where the stiffness of the shell decreases with increasing pH, confirms the predicted onset of failure as a function of the FvK number.

  15. 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).

  16. 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).

  17. 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).

  18. 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).

  19. 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).

  20. Hyperkalemia in Heart Failure.

    PubMed

    Sarwar, Chaudhry M S; Papadimitriou, Lampros; Pitt, Bertram; Piña, Ileana; Zannad, Faiez; Anker, Stefan D; Gheorghiade, Mihai; Butler, Javed

    2016-10-01

    Disorders of potassium homeostasis can potentiate the already elevated risk of arrhythmia in heart failure. Heart failure patients have a high prevalence of chronic kidney disease, which further heightens the risk of hyperkalemia, especially when renin-angiotensin-aldosterone system inhibitors are used. Acute treatment for hyperkalemia may not be tolerated in the long term. Recent data for patiromer and sodium zirconium cyclosilicate, used to treat and prevent high serum potassium levels on a more chronic basis, have sparked interest in the treatment of hyperkalemia, as well as the potential use of renin-angiotensin-aldosterone system inhibitors in patients who were previously unable to take these drugs or tolerated only low doses. This review discusses the epidemiology, pathophysiology, and outcomes of hyperkalemia in heart failure; provides an overview of traditional and novel ways to approach management of hyperkalemia; and discusses the need for further research to optimally treat heart failure.

  1. Hyperkalemia in Heart Failure.

    PubMed

    Sarwar, Chaudhry M S; Papadimitriou, Lampros; Pitt, Bertram; Piña, Ileana; Zannad, Faiez; Anker, Stefan D; Gheorghiade, Mihai; Butler, Javed

    2016-10-01

    Disorders of potassium homeostasis can potentiate the already elevated risk of arrhythmia in heart failure. Heart failure patients have a high prevalence of chronic kidney disease, which further heightens the risk of hyperkalemia, especially when renin-angiotensin-aldosterone system inhibitors are used. Acute treatment for hyperkalemia may not be tolerated in the long term. Recent data for patiromer and sodium zirconium cyclosilicate, used to treat and prevent high serum potassium levels on a more chronic basis, have sparked interest in the treatment of hyperkalemia, as well as the potential use of renin-angiotensin-aldosterone system inhibitors in patients who were previously unable to take these drugs or tolerated only low doses. This review discusses the epidemiology, pathophysiology, and outcomes of hyperkalemia in heart failure; provides an overview of traditional and novel ways to approach management of hyperkalemia; and discusses the need for further research to optimally treat heart failure. PMID:27687200

  2. What Causes Heart Failure?

    MedlinePlus

    ... the heart, leading to heart failure. High Blood Pressure Blood pressure is the force of blood pushing against the ... weaken your heart and lead to plaque buildup. Blood pressure is considered high if it stays at or ...

  3. 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 ...

  4. Types of Heart Failure

    MedlinePlus

    ... to be made. Here we delve into the importance of shared decision making. This content was last ... heart failure. Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Low Blood Pressure ...

  5. Classes of Heart Failure

    MedlinePlus

    ... to be made. Here we delve into the importance of shared decision making. HF Resources For Life ... heart failure. Popular Articles 1 Understanding Blood Pressure Readings 2 Sodium and Salt 3 Low Blood Pressure ...

  6. 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.

  7. Kidney (Renal) Failure

    MedlinePlus

    ... renal function using ureteral stenting, nephrostomy, surgery or dialysis. What is kidney (renal) failure? How is kidney ... as a urinary stent or kidney stone removal. Dialysis , including hemodialysis and peritoneal dialysis: These procedures remove ...

  8. What Causes Respiratory Failure?

    MedlinePlus

    ... easily move oxygen into your blood and remove carbon dioxide from your blood (gas exchange). This can cause a low oxygen level or high carbon dioxide level, or both, in your blood. Respiratory failure ...

  9. 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.

  10. 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.

  11. Troponins in heart failure.

    PubMed

    Omland, T; Røsjø, H; Giannitsis, E; Agewall, S

    2015-03-30

    The signs and symptoms of heart failure are frequently unspecific and correlate poorly with objective indices of cardiac function. Objective assessment of cardiac function by echocardiography or other imaging modalities also correlate poorly with symptomatic status and functional capacity. Accordingly, there is a need for circulating biomarkers that can provide incremental diagnostic and prognostic information to the existing armamentarium of tests. The introduction of more sensitive assays that allow determination of very low circulating concentrations of the myofibrillar proteins cardiac troponin I and T has not only resulted in improved diagnostic accuracy in the setting of acute coronary syndromes. The high sensitivity assays have also shown that cardiac troponins are frequently found chronically circulating in a variety of acute and chronic, cardiac and non-cardiac disease conditions, including acute heart failure and chronic symptomatic and asymptomatic left ventricular dysfunction. Cardiac troponin I and T provide may provide clinically useful prognostic information both concerning the future risk of developing heart failure in asymptomatic subjects and the risk of fatal events and hospital admissions in those with already established heart failure This review summarizes current literature on the clinical performance and utility of cardiac troponin measurements as diagnostic and prognostic tools in patients with symptomatic heart failure, as well as in those with asymptomatic left ventricular dysfunction, and clinical phenotypes at high risk for developing heart failure, including stable coronary artery disease, left ventricular hypertrophy, and aortic stenosis.

  12. 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.

  13. Heart failure and sleep disorders.

    PubMed

    Parati, Gianfranco; Lombardi, Carolina; Castagna, Francesco; Mattaliano, Paola; Filardi, Pasquale Perrone; Agostoni, Piergiuseppe

    2016-07-01

    Awareness of the importance of sleep-related disorders in patients with cardiovascular diseases is growing. In particular, sleep-disordered breathing, short sleep time, and low sleep quality are frequently reported by patients with heart failure (HF). Sleep-disordered breathing, which includes obstructive sleep apnoea (OSA) and central sleep apnoea (CSA), is common in patients with HF and has been suggested to increase the morbidity and mortality in these patients. Both OSA and CSA are associated with increased sympathetic activation, vagal withdrawal, altered haemodynamic loading conditions, and hypoxaemia. Moreover, OSA is strongly associated with arterial hypertension, the most common risk factor for cardiac hypertrophy and failure. Intrathoracic pressure changes are also associated with OSA, contributing to haemodynamic alterations and potentially affecting overexpression of genes involved in ventricular remodelling. HF treatment can decrease the severity of both OSA and CSA. Indeed, furosemide and spironolactone administration, exercise training, cardiac resynchronization therapy, and eventually heart transplantation have shown a positive effect on OSA and CSA in patients with HF. At present, whether CSA should be treated and, if so, which is the optimal therapy is still debated. By contrast, more evidence is available on the beneficial effects of OSA treatment in patients with HF.

  14. 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.

  15. 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.

  16. Judicial failure to thrive.

    PubMed

    Stern, H P; Casey, P H

    1984-06-01

    The case of a toddler who developed nonorganic failure to thrive during the course of a custody determination is reported. The child demonstrated physical, emotional, and developmental aspects of failure to thrive. These signs correlated with custody ordered by the judge, during which time the child's care was alternated between parents. The symptoms resolved when the child was in the hospital and when provided stable care by his grandmother. With the increasing frequency of divorce, failure to thrive resulting from judicial decisions will probably increase. Physicians should monitor these children carefully in order to prevent serious psychosocial complications. The judicial system should expedite custody decisions, availing itself of information in child development. PMID:6736261

  17. 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

  18. Management of acute decompensated heart failure.

    PubMed

    Varughese, Sheeba

    2007-01-01

    Heart failure, a debilitating complex clinical syndrome, affects nearly 5 million people in the United States and presents a heavy socioeconomic burden. Neurohormonal abnormalities contribute to the pathophysiology of heart failure. Acute decompensated heart failure (ADHF) has emerged as a major health problem associated with poor prognosis, increased costs related to care, reduced quality of life, and frequent readmissions. Symptoms of ADHF are primarily related to congestion and/or low perfusion states. The use of biomakers such as B-natriuretic peptides is useful in distinguishing between cardiac and noncardiac causes of symptoms. Treatment for ADHF begins with identification and treatment of precipitating factors for acute decompensation. Initial goal of therapy is focused on symptom management followed by interventions that delay disease progression, reduce readmission, and prolong survival. PMID:17356351

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. Living with Heart Failure

    MedlinePlus

    ... should be. This includes advice on daily activities, work, leisure time, sex, and exercise. Your level of activity will depend on the stage of your heart failure (how severe it is). Keep all of your ... to get tests and lab work. Your doctor needs the results of these tests ...

  4. Failure Free Reading.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    This paper provides an overview of Failure Free Reading, a program with the primary goal of providing a basic understanding of the reading process to students in grades K-12 with pronounced reading difficulty and move them into traditional reading programs. The program is targeted to and most effective with at-risk and English as a Second Language…

  5. 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 the 1st…

  6. Premature Ovarian Failure

    MedlinePlus

    Premature ovarian failure (POF) is when a woman's ovaries stop working before she is 40. POF is different from premature menopause. With premature menopause, ... be a disease, surgery, chemotherapy, or radiation. With POF, some women still have occasional periods. They may ...

  7. 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,…

  8. Explaining Jewish Student Failure.

    ERIC Educational Resources Information Center

    Schoem, David

    1982-01-01

    Ethnographic study of a suburban Jewish afternoon school suggests that students' failure to meet school behavior and learning standards occurred because they did not value or understand the rewards made available to them through the school and because their means of achieving status mobility had shifted away from the Jewish school. (Author/GC)

  9. 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…

  10. 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

  11. Determined to Fail--the Role of Genetic Mechanisms in Heart Failure.

    PubMed

    Kayvanpour, Elham; Katus, Hugo A; Meder, Benjamin

    2015-10-01

    Genetic variants contribute to several steps during heart failure pathophysiology. The mechanisms include frequent polymorphisms that increase the susceptibility to heart failure in the general population and rare variants as causes of an underlying cardiomyopathy. In this review, we highlight recent discoveries made by genetic approaches and provide an outlook onto the role of epigenetic modifiers of heart failure.

  12. 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.

  13. 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

  14. Mitochondrial dysfunction in heart failure.

    PubMed

    Rosca, Mariana G; Hoppel, Charles L

    2013-09-01

    Heart failure (HF) is a complex chronic clinical syndrome. Energy deficit is considered to be a key contributor to the development of both cardiac and skeletal myopathy. In HF, several components of cardiac and skeletal muscle bioenergetics are altered, such as oxygen availability, substrate oxidation, mitochondrial ATP production, and ATP transfer to the contractile apparatus via the creatine kinase shuttle. This review focuses on alterations in mitochondrial biogenesis and respirasome organization, substrate oxidation coupled with ATP synthesis in the context of their contribution to the chronic energy deficit, and mechanical dysfunction of the cardiac and skeletal muscle in HF. We conclude that HF is associated with decreased mitochondrial biogenesis and function in both heart and skeletal muscle, supporting the concept of a systemic mitochondrial cytopathy. The sites of mitochondrial defects are located within the electron transport and phosphorylation apparatus and differ with the etiology and progression of HF in the two mitochondrial populations (subsarcolemmal and interfibrillar) of cardiac and skeletal muscle. The roles of adrenergic stimulation, the renin-angiotensin system, and cytokines are evaluated as factors responsible for the systemic energy deficit. We propose a cyclic AMP-mediated mechanism by which increased adrenergic stimulation contributes to the mitochondrial dysfunction.

  15. Mitochondrial dysfunction in heart failure

    PubMed Central

    Rosca, Mariana G.; Hoppel, Charles L.

    2013-01-01

    Heart failure (HF) is a complex chronic clinical syndrome. Energy deficit is considered to be a key contributor to the development of both cardiac and skeletal myopathy. In HF several components of cardiac and skeletal muscle bioenergetics are altered, such as oxygen availability, substrate oxidation, mitochondrial ATP production, and ATP transfer to the contractile apparatus via the creatine kinase shuttle. This review focuses on alterations in mitochondrial biogenesis and respirasome organization, substrate oxidation coupled with ATP synthesis in the context of their contribution to the chronic energy deficit, and mechanical dysfunction of the cardiac and skeletal muscle in HF. We conclude that HF is associated with decreased mitochondrial biogenesis and function in both heart and skeletal muscle, supporting the concept of a systemic mitochondrial cytopathy. The sites of mitochondrial defects are located within the electron transport and phosphorylation apparatus, and differ with the etiology and progression of HF in the two mitochondrial populations (subsarcolemmal and interfibrillar) of cardiac and skeletal muscle. The roles of adrenergic stimulation, the renin-angiotensin system, and cytokines are evaluated as factors responsible for the systemic energy deficit. We propose a cylic AMP-mediated mechanism by which increased adrenergic stimulation contributes to the mitochondrial dysfunction. PMID:22948484

  16. 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

  17. Satellite failures revisited

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-12-01

    In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

  18. Diastolic heart failure.

    PubMed

    Gary, Rebecca; Davis, Leslie

    2008-01-01

    Diastolic heart failure (DHF) is estimated to occur in 40% to 50% of patients with heart failure. Evidence suggests that DHF is primarily a cardiogeriatric syndrome that increases from approximately 1% at age 50 years to 10% or more at 80 years. DHF is also more likely to occur in older women who are hypertensive or diabetic. Although survival is better in patients with DHF compared with systolic heart failure, mortality rates for patients with DHF are four times higher than those for healthy, community-dwelling older adults. The increase in DHF is anticipated to continue during the next several decades largely because of the aging of the population; increase in risk factors associated with hypertension, diabetes, and obesity; and ongoing technologic advances in the treatment of cardiovascular disease. Few clinical trials have evaluated therapy in this population, so evidence about the effectiveness of treatment strategies for DHF is limited. Future research should target novel interventions that specifically target patients with DHF who are typically older and female, and experience exertional intolerance and have a considerably reduced quality of life.

  19. Heart Failure Society of America

    MedlinePlus

    ... Review Course in Advanced Heart Failure and Transplant Cardiology is now available OnDemand! Monday, August 29, 2016! ... than expected, and the FDA... European Society of Cardiology – Heart Failure 2017 October 11, 2016 ESC: Heart ...

  20. Failure Analysis for Improved Reliability

    NASA Technical Reports Server (NTRS)

    Sood, Bhanu

    2016-01-01

    Outline: Section 1 - What is reliability and root cause? Section 2 - Overview of failure mechanisms. Section 3 - Failure analysis techniques (1. Non destructive analysis techniques, 2. Destructive Analysis, 3. Materials Characterization). Section 4 - Summary and Closure

  1. Heart failure prognostic model.

    PubMed

    Axente, L; Sinescu, C; Bazacliu, G

    2011-05-15

    Heart failure (HF) is a common, costly, disabling and deadly syndrome. Heart failure is a progressive disease characterized by high prevalence in society, significantly reducing physical and mental health, frequent hospitalization and high mortality (50% of the patients survive up to 4 years after the diagnosis, the annual mortality varying from 5% to 75%). The purpose of this study is to develop a prognostic model with easily obtainable variables for patients with heart failure. METHODS AND RESULTS. Our lot included 101 non-consecutive hospitalized patients with heart failure diagnosis. It included 49.5% women having the average age of 71.23 years (starting from 40 up to 91 years old) and the roughly estimated period for monitoring was 35.1 months (5-65 months). Survival data were available for all patients and the median survival duration was of 44.0 months. A large number of variables (demographic, etiologic, co morbidity, clinical, echocardiograph, ECG, laboratory and medication) were evaluated. We performed a complex statistical analysis, studying: survival curve, cumulative hazard, hazard function, lifetime distribution and density function, meaning residual life time, Ln S (t) vs. t and Ln(H) t vs. Ln (t). The Cox multiple regression model was used in order to determine the major factors that allow the forecasting survival and their regression coefficients: age (0.0369), systolic blood pressure (-0.0219), potassium (0.0570), sex (-0.3124) and the acute myocardial infarction (0.2662). DISCUSSION. Our model easily incorporates obtainable variables that may be available in any hospital, accurately predicting survival of the heart failure patients and enables risk stratification in a few hours after the patients' presentation. Our model is derived from a sample of patients hospitalized in an emergency department of cardiology, some with major life-altering co morbidities. The benefit of being aware of the prognosis of these patients with high risk is extremely

  2. Detecting servo failures with software

    NASA Technical Reports Server (NTRS)

    Lew, D.; Quam, R.

    1979-01-01

    Program detects hardware failure in servosystems by comparing actual servo valve position with predictions of software model. In addition, system will also pick up most computer input/output failures. Process presents faster and more reliable results than previous failure detection methods.

  3. Planning Ahead: Advanced Heart Failure

    MedlinePlus

    ... Pressure Tools & Resources Stroke More Planning Ahead: Advanced Heart Failure Updated:Aug 24,2016 An important part of ... content was last reviewed on 04/16/2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  4. Your Heart Failure Healthcare Team

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Your Heart Failure Healthcare Team Updated:Mar 25,2016 Patients with ... to the Terms and Conditions and Privacy Policy Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  5. Management of Noncardiac Comorbidities in Chronic Heart Failure.

    PubMed

    Chong, Vun Heng; Singh, Jagdeep; Parry, Helen; Saunders, Jocelyn; Chowdhury, Farhad; Mancini, Donna M; Lang, Chim C

    2015-10-01

    Prevalence of heart failure is increasing, especially in the elderly population. Noncardiac comorbidities complicate heart failure care and are increasingly common in elderly patients with reduced or preserved ejection fraction heart failure, owing to prolongation of patient's lives by advances in chronic heart failure (CHF) management. Common comorbidities include respiratory disease, renal dysfunction, anemia, arthritis, obesity, diabetes mellitus, cognitive dysfunction, and depression. These conditions contribute to the progression of the disease and may alter the response to treatment, partly as polypharmacy is inevitable in these patients. Cardiologists and other physicians caring for patients with CHF need to be vigilant to comorbid conditions that complicate the care of these patients. There is now more guidance on management of noncardiac comorbidities in heart failure, and this article contains a comprehensive review of the most recent updates on management of noncardiac comorbidities in CHF.

  6. 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.

  7. 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

  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. Renal failure in Yemen.

    PubMed

    Al-Rohani, M

    2004-01-01

    Renal failure remains a serious cause of mortality in Yemen. Our region has 1.25 million population and our hospital is the central hospital, which has a nephrology department and performs dialysis for the region. Between January 1998 and December 2002, we admitted 547 patients; including children, with acute renal failure (ARF) and chronic renal failure (CRF). CRF was observed in 400 patients, an incidence of 64 per million per year and a prevalence of 320 per million. ARF occurred in 147 persons with an incidence of 23.5 per million per year and a prevalence of 117.5 patients per million. Of all patients, 72% were adults (age range, 20-60 years) with a male preponderance. As a tropical country, malaria (27.9%), diarrhea (13.6%), and other infectious diseases were the main causes. Next most common were obstructive diseases causing CRF and ARF (26.8% and 12.9%, respectively), mainly urolithiasis, Schistosomiasis, and prostatic enlargement. However the cause of CRF in 57.5% of patients was unknown as most persons presented late with end-stage disease (64.7%), requiring immediate intervention. Other causes, such as hepatorenal syndrome, snake bite, diabetes mellitus, and hypertension, showed low occurrence rates. Patients presented to the hospital mostly in severe uremia and without a clear history of prior medications. The major findings were vomiting, acidosis, and hypertension with serum creatinine values ranging between 2.8-45 mg/dL (mean value, 13.4 mg/dL). Anemia was observed in 80.4% of CRF versus 62.6% of ARF patients. Hypertension prevalence was 65.5% among CRF patients, of whom 25% were in hypertensive crisis, whereas among ARF the prevalence was only 26.5%. PMID:15350475

  10. 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.

  11. Sleep and Heart Failure.

    PubMed

    Nelson, Kimberly A; Trupp, Robin J

    2015-12-01

    Sleep deprivation occurs for many reasons but, when chronic in nature, has many consequences for optimal health and performance. Despite its high prevalence, sleep-disordered breathing is underrecognized and undertreated. This is especially true in the setting of heart failure, where sleep-disordered breathing affects more than 50% of patients. Although the optimal strategy to best identify patients is currently unknown, concerted and consistent efforts to support early recognition, diagnosis, and subsequent treatment should be encouraged. Optimization of guideline-directed medical therapy and concurrent treatment of sleep-disordered breathing are necessary to improve outcomes in this complex high-risk population. PMID:26567495

  12. 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.

  13. [Cardiac failure in endocrine diseases].

    PubMed

    Hashizume, K

    1993-05-01

    Several endocrine diseases show the symptoms of cardiac failure. Among them, patients with acromegaly show a specific cardiomyopathy which results in a severe left-sided cardiac failure. Hypoparathyroidism also induces cardiac failure, which is resulted from hypocalcemia and low levels of serum parathyroid hormone. In the cases of hypothyroidism, the patients with myxedemal coma show a severe cardiac failure, which is characterized by disturbance of central nervous system, renal function, and cardiac function. In the patients with thyroid crisis (storm), the cardiac failure comes from the great reduction of cardiac output with dehydration. The reduction of circulation volume, observed in the patients with pheochromocytoma easily induces cardiac failure (shock) just after the removal of adrenal tumor. In patients with malignant carcinoid syndrome, right-sided ventricular failure which may be occurred through the actions of biogenic amines is observed. PMID:8331806

  14. 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.

  15. 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.

  16. Telomeres and marrow failure.

    PubMed

    Calado, Rodrigo T

    2009-01-01

    Telomeres, repeat sequences at the ends of chromosomes, are protective chromosomal structures highly conserved from primitive organisms to humans. Telomeres inevitably shorten with every cell cycle, and telomere attrition has been hypothesized to be fundamental to normal senescence of cells, tissues, and organisms. Molecular mechanisms have evolved to maintain their length and protective function; telomerase (TERT) is a reverse transcriptase enzyme that uses an RNA molecule (TERC) as the template to elongate the 3' ends of telomeres. Shelterin is a collection of DNA-binding proteins that cover and protect telomeres. The recent discovery of inherited mutations in genes that function to repair telomeres as etiologic in a range of human diseases, which have clinical manifestations in diverse tissues, including the hematopoietic tissue, suggests that defects in telomere repair and protection can cause organ failure. Dyskeratosis congenita is the prototype of telomere diseases; it is characterized by bone marrow failure, mucocutaneous abnormalities, pulmonary fibrosis, liver cirrhosis, and increased susceptibility to cancer, including acute myeloid leukemia. Aplastic anemia, acute myeloid leukemia, and idiopathic pulmonary fibrosis also are associated with inherited mutations in telomere repair or protection genes. Additionally, telomere defects associate with predisposition to hematologic malignancy and epithelial tumors. Telomere erosion is abnormally rapid in patients with mutations in telomerase genes but also after hematopoietic stem cell transplant, and telomeres are naturally shorter in older individuals-all conditions associated with higher rates of malignant diseases. In human tissue culture, short telomeres produce end-to-end chromosome fusion, nonreciprocal translocations, and aneuploidy.

  17. Fracture, failure, and fragmentation

    SciTech Connect

    Dienes, J.K.

    1984-01-01

    Though continuum descriptions of material behavior are useful for many kinds of problems, particularly those involving plastic flow, a more general approach is required when the failure is likely to involve growth and coalescence of a large number of fractures, as in fragmentation. Failures of this kind appear frequently in rapid dynamic processes such as those resulting from impacts and explosions, particularly in the formation of spall fragments. In the first part of this paper an approach to formulating constitutive relations that accounts for the opening, shear and growth of an ensemble of cracks is discussed. The approach also accounts for plastic flow accompanying fragmentation. The resulting constitutive relations have been incorporated into a Lagrangean computer program. In the second part of this paper a theoretical approach to coalescence is described. The simplest formulation makes use of 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 is also described in which the decrease of the mean free path with increasing crack size is accounted for, but the crack distribution is assumed isotropic. 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.

  18. Obesity and heart failure.

    PubMed

    De Pergola, Giovanni; Nardecchia, Adele; Giagulli, Vito Angelo; Triggiani, Vincenzo; Guastamacchia, Edoardo; Minischetti, Manuela Castiglione; Silvestris, Franco

    2013-03-01

    Epidemiological studies have recently shown that obesity, and abdominal obesity in particular, is an independent risk factor for the development of heart failure (HF). Higher cardiac oxidative stress is the early stage of heart dysfunction due to obesity, and it is the result of insulin resistance, altered fatty acid and glucose metabolism, and impaired mitochondrial biogenesis. Extense myocyte hypertrophy and myocardial fibrosis are early microscopic changes in patients with HF, whereas circumferential strain during the left ventricular (LV) systole, LV increase in both chamber size and wall thickness (LV hypertrophy), and LV dilatation are the early macroscopic and functional alterations in obese developing heart failure. LV hypertrophy leads to diastolic dysfunction and subendocardial ischemia in obesity, and pericardial fat has been shown to be significantly associated with LV diastolic dysfunction. Evolving abnormalities of diastolic dysfunction may include progressive hypertrophy and systolic dysfunction, and various degrees of eccentric and/or concentric LV hypertrophy may be present with time. Once HF is established, overweight and obese have a better prognosis than do their lean counterparts with the same level of cardiovascular disease, and this phenomenon is called "obesity paradox". It is mainly due to lower muscle protein degradation, brain natriuretic peptide circulating levels and cardio-respiratory fitness than normal weight patients with HF.

  19. 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.

  20. 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

  1. 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.

  2. 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. PMID:27420388

  3. 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.

  4. Mesoscale simulation of concrete spall failure

    NASA Astrophysics Data System (ADS)

    Knell, S.; Sauer, M.; Millon, O.; Riedel, W.

    2012-05-01

    Although intensively studied, it is still being debated which physical mechanisms are responsible for the increase of dynamic strength and fracture energy of concrete observed at high loading rates, and to what extent structural inertia forces on different scales contribute to the observation. We present a new approach for the three dimensional mesoscale modelling of dynamic damage and cracking in concrete. Concrete is approximated as a composite of spherical elastic aggregates of mm to cm size embedded in an elastic cement stone matrix. Cracking within the matrix and at aggregate interfaces in the μm range are modelled with adaptively inserted—initially rigid—cohesive interface elements. The model is applied to analyse the dynamic tensile failure observed in Hopkinson-Bar spallation experiments with strain rates up to 100/s. The influence of the key mesoscale failure parameters of strength, fracture energy and relative weakening of the ITZ on macromechanic strength, momentum and energy conservation is numerically investigated.

  5. 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.

  6. 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

  7. Insomnia Self-Management in Heart Failure

    ClinicalTrials.gov

    2016-05-11

    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

  8. 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

  9. 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.

  10. 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. PMID:27112279

  11. 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.

  12. Copeptin in Heart Failure.

    PubMed

    Balling, Louise; Gustafsson, Finn

    2016-01-01

    Heart failure (HF) is one of the most common causes of hospitalization and mortality in the modern Western world and an increasing proportion of the population will be affected by HF in the future. Although HF management has improved quality of life and prognosis, mortality remains very high despite therapeutic options. Medical management consists of a neurohormonal blockade of an overly activated neurohormonal axis. No single marker has been able to predict or monitor HF with respect to disease progression, hospitalization, or mortality. New methods for diagnosis, monitoring therapy, and prognosis are warranted. Copeptin, a precursor of pre-provasopressin, is a new biomarker in HF with promising potential. Copeptin has been found to be elevated in both acute and chronic HF and is associated with prognosis. Copeptin, in combination with other biomarkers, could be a useful marker in the monitoring of disease severity and as a predictor of prognosis and survival in HF. PMID:26975969

  13. Failure to control gonorrhoea

    PubMed Central

    Guthe, T.

    1961-01-01

    There is increasing evidence of emerging resistance of the gonococcus to antibiotics, particularly penicillin, but apparent resistance may sometimes be due to concomitant infection with micro-organisms other than the gonococcus, which are not susceptible to this antibiotic. There is also evidence that clinical complications, particularly in the female, are much more frequent than was previously believed to be the case. The incidence of gonorrhoea has increased significantly in many countries in spite of the availability of the ”ideal” drug, penicillin. The reasons for the failure to control gonorrhoea in the individual and in the mass of patients are discussed, taking into account a number of factors relating to emerging drug resistance of the gonococcus, insufficient criteria for diagnosis, the possibility of persistence of infection and increased frequency of reinfection. PMID:13709981

  14. 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.

  15. Premature ovarian failure.

    PubMed

    Vujović, Svetlana; Ivović, Miomira; Tancić-Gajić, Milina; Marina, Ljiljana; Barać, Marija; Arizanović, Zorana; Nenezić, Ana; Ivanisević, Maja; Micić, Jelena; Sajić, Silvija; Micić, Dragan

    2012-01-01

    Premature ovarian failure (POF) is the occurrence of hypergonadotropic hypoestrogenic amenorrhea in women under the age of forty years. It is idiopathic in 74-90% patients. Known cases can be divided into primary and secondary POF. In primary POF genetic aberrations can involve the X chromosome (monosomy, trisomy, translocations, deletions) or autosomes. Genetic mechanisms include reduced gene dosage and non-specific chromosome effects impairing meiosis, decreasing the pool of primordial follicles and increasing atresia due to apoptosis or failure of follicle maturation. Autoimmune ovarian damage is caused by alteration of T-cell subsets and T-cell mediated injury, increase of autoantibody producing B-cells, a low number of effector/cytotoxic lymphocyte, which decreases the number and activity of natural killer cells. Bilateral oophorectomy, chemotherapy, radiotherapy and infections cause the secondary POF. Symptoms of POF include irritability, nervousness, loss of libido, depression, lack of concentration, hot flushes, weight gaining, dry skin, vaginal dryness, frequent infections etc.The diagnosis is confirmed by the level of FSH of over 40 IU/L and estradiol below 50 pmol/L in women aged below 40 years. Biochemical and other hormonal analysis (free thyroxin, TSH, prolactin, testosterone), karyotype (<30 years of age), ultrasound of the breasts and pelvis are advisable. Optimal therapy is combined estrogen progestagen therapy given in a sequential rhythm, after excluding absolute contraindications. Testosterone can be added to adnexectomized women and those with a low libido. Sequential estrogen progestagen replacement therapy is the first line therapy for ovulation induction in those looking for pregnancy and after that oocyte donation will be advised. Appropriate estro-progestagen therapy improves the quality of life and prevents complications such as cardiovascular diseases, osteoporosis, stroke etc. PMID:23350261

  16. Cancer risk in DES daughters

    PubMed Central

    Verloop, Janneke; van Leeuwen, Flora E.; Helmerhorst, Theo J. M.; van Boven, Hester H.

    2010-01-01

    Objective We examined long-term risk of cancer in women exposed to diethylstilbestrol (DES) in utero. Methods A total of 12,091 DES-exposed women in the Netherlands were followed prospectively from December 1992 till June 2008. Cancer incidence was assessed through linkage with the Dutch pathology database (PALGA) and the Netherlands Cancer Registry and compared with the Dutch female population. Results A total of 348 medically verified cancers occurred; median age at end of follow-up was 44.0 years. No overall increased risk of cancer was found (standardized incidence ratio [SIR] = 1.01; 95% confidence interval [CI] = 0.91, 1.13). The risk of clear cell adenocarcinoma of the vagina and cervix (CCA) was statistically significantly increased (SIR = 24.23; 95% CI = 8.89, 52.74); the elevated risk persisted above 40 years of age. The risk of melanoma diagnosed before age 40 was increased (SIR = 1.59; 95% CI = 1.08, 2.26). No excess risks were found for other sites, including breast cancer. Conclusions Except for an elevated risk of CCA, persisting at older ages, and an increased risk of melanoma at young ages, we found no increased risk of cancer. Longer follow-up is warranted to examine cancer risk at ages when cancer occurs more frequently. Electronic supplementary material The online version of this article (doi:10.1007/s10552-010-9526-5) contains supplementary material, which is available to authorized users. PMID:20204493

  17. The enhancement of existing DES Maplet interface

    NASA Astrophysics Data System (ADS)

    Abdullah, Nur Lina; Mutalip, Rasidah Abdull; Abdullah, Kamilah

    2014-07-01

    This study pertains to the process of Data Encryption Standard, DES. DES consists of encryption and decryption processes linked with mathematical elements such as algebra and number theory. Preliminary, studies revealed that most of mathematics students face a problem in understanding the complicated process of DES. In modern learning methods, learning environment becomes more interesting with the use of computer and a variety of mathematical software packages. Several mathematical softwares such as Maple, Mathematica, Mathlab and Sage were developed in order to fulfill the specific calculation requirements. Correspondingly, motivated from that, this study incorporated with Maple to enhance the existing DES Maplet interface to be more interactive and user-friendly compared to the original version.

  18. Probabilistic Failure Assessment For Fatigue

    NASA Technical Reports Server (NTRS)

    Moore, Nicholas; Ebbeler, Donald; Newlin, Laura; Sutharshana, Sravan; Creager, Matthew

    1995-01-01

    Probabilistic Failure Assessment for Fatigue (PFAFAT) package of software utilizing probabilistic failure-assessment (PFA) methodology to model high- and low-cycle-fatigue modes of failure of structural components. Consists of nine programs. Three programs perform probabilistic fatigue analysis by means of Monte Carlo simulation. Other six used for generating random processes, characterizing fatigue-life data pertaining to materials, and processing outputs of computational simulations. Written in FORTRAN 77.

  19. 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

  20. Heart failure in South America.

    PubMed

    Bocchi, Edimar Alcides

    2013-05-01

    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.

  1. 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

  2. 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.

  3. 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…

  4. 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. PMID:26816169

  5. Rescue of Heart Failure by Mitochondrial Recovery

    PubMed Central

    2016-01-01

    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. PMID:27032551

  6. 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

  7. Fulminant hepatic failure.

    PubMed

    Sass, David A; Shakil, A Obaid

    2003-12-01

    FHF is a devastating illness of varied causes, carrying considerable mortality and affecting patients with previously healthy livers. The clinical presentation varies widely but encephalopathy is the defining criterion. Management requires a multidisciplinary approach, including rapid triage, monitoring, and referral to a transplantation center for further evaluation. Early prognostication and timely availability of donor livers are essential for a successful outcome. A donor shortage, however, continues to pose problems for both hepatologists and surgeons. Effective liver support devices may greatly prolong the window of opportunity to provide a donor liver, or alternatively to allow the native liver to regenerate. Despite decades of great progress in the field of liver support systems, the ideal system is still a long-cherished goal in hepatology. Hybrid systems have garnered most of the recent attention, but the quest for improved synthetic function has not yet been realized. It is hoped that rapid conceptual and technologic developments with respect to hybrid systems, hepatocyte transplantation, and xenografting will yield a safe and accessible tool for managing these critically ill patients. Controlled, multicenter trials in well-defined patient groups and with standard outcome measures are essential to evaluate the clinical value of these devices. A better understanding of mechanisms responsible for liver cell death and multiorgan failure, and the development of strategies to enhance liver regeneration, may allow a more targeted approach to therapy.

  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.

  9. 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.

  10. 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…

  11. Analysis of electronic component failures using high-density radiography

    SciTech Connect

    Tuohig, W.D.; Potter, T.J.

    1991-11-01

    The exceptional resolution and nondestructive nature of microfocus radiography has proven to be extremely useful in the diagnosis of electronic component failures, particularly when the components are contained in sealed or encapsulated assemblies. An epoxy-encapsulated NTC thermistor and an epitaxial silicon P-N junction photodetector are examples of discrete devices in which the cause of failure was correctly hypothesized directly from a radiographic image. Subsequent destructive physical examinations confirmed the initial hypothesis and established the underlying cause in each case. The problem in a vacuum switch tube which failed to function was apparent in the radiographic image, but the underlying cause was not clear. However, radiography also showed that the position of a flat cable in the assembly could contribute to failure, an observation which resulted in a change in manufacturing procedure. In each of these instances, microradiography played a key role in decisions concerning the root cause of failure, product viability, and corrective action. 15 refs., 10 figs.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. [Premature ovarian failures].

    PubMed

    Bricaire, Léopoldine; Laroche, Emmanuelle; Bourcigaux, Nathalie; Donadille, Bruno; Christin-Maitre, Sophie

    2013-11-01

    Premature ovarian failure (POF) is clinically suspected by amenorrhea and confirmed by an elevated FSH serum level above 40 mUI/L (even 20 mUI/L) twice, in a woman before the age of 40. Prevalence of POF is between 1 to 2% in women. In 90% of cases, no aetiology is identified. Obvious causes are chemotherapy, pelvic radiotherapy, ovarian surgery and diethylstilbestrol exposure in utero. A karyotype should be performed as Turner Syndrome is the most frequent genetic cause of POF. Some X abnormalities such as X deletion or X autosome translocation can be found. FMR1 pre-mutation (fragile X syndrome) should be searched for, even though no cases of mental retardation are known, in the family. Other genetic abnormalities can be suggested by associated symptoms (i.e.: FOXL2, SF1 mutations). Auto-immune aetiology can be suspected if other auto-immune features are present, however, there are no reliable auto-antibodies to confirm auto-immunity in POF. Treatment of POF is based on hormonal replacement therapy in order to avoid estrogen deficiency, suppress vasomotor symptoms and avoid bone loss as well as cardiovascular risk. Estrogens should be associated with progesterone or a progestin, at least up to the age of 51. Patients with POF should be informed that spontaneous pregnancies may occur (in 5% of cases). In case of desire of pregnancy, the patient should be oriented to a specialized unit for in vitro fertilization with oocyte donation. Psychological support is essential and should be part of the treatment. POF is associated with an increased risk of emotional distress and depression. No preventive treatment of POF is available so far. PMID:24157186

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:27547136

  1. 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.

  2. 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

  3. New medications for heart failure.

    PubMed

    Gordin, Jonathan S; Fonarow, Gregg C

    2016-08-01

    Heart failure is common and results in substantial morbidity and mortality. Current guideline-based therapies for heart failure with reduced ejection fraction, including beta blockers, angiotensin converting enzyme (ACE) inhibitors, and aldosterone antagonists aim to interrupt deleterious neurohormonal pathways and have shown significant success in reducing morbidity and mortality associated with heart failure. Continued efforts to further improve outcomes in patients with heart failure with reduced ejection fraction have led to the first new-in-class medications approved for heart failure since 2005, ivabradine and sacubitril/valsartan. Ivabradine targets the If channels in the sinoatrial node of the heart, decreasing heart rate. Sacubitril/valsartan combines a neprilysin inhibitor that increases levels of beneficial vasodilatory peptides with an angiotensin receptor antagonist. On a background of previously approved, guideline-directed medical therapies for heart failure, these medications have shown improved clinical outcomes ranging from decreased hospitalizations in a select group of patients to a reduction in all-cause mortality across all pre-specified subgroups. In this review, we will discuss the previously established guideline-directed medical therapies for heart failure with reduced ejection fraction, the translational research that led to the development of these new therapies, and the results from the major clinical trials of ivabradine and sacubitril/valsartan. PMID:27038558

  4. 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.

  5. 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.

  6. 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

  7. [Syndrome of multiple organ failure].

    PubMed

    Charbonneau, P; Suisse, A

    1990-11-01

    The multiple organ failure syndrome (MOF) is a relatively new entity defined as the successive occurrence of respiratory (ARDS), hepatic, renal, myocardial, gastro-intestinal or neurological failure in patients with hyperkinetic haemodynamic and hypermetabolic states. The etiologies are: infection, septic and non-septic shock, burns and multiple injuries. The MOF syndrome is considered to be a generalised "inflammatory reaction" to tissue aggression involving a cascade of mediatory factors (TNF, interleukines...) of macrophagic, lymphocytic origin, causing multiple organ failure. The treatment depends on early correction of cellular hypoxia related to circulatory disturbances, nutritional support, anti-infective therapy and, in the near future, "control of mediator activity" (immunotherapy).

  8. Offshore pipeline failures. Master's thesis

    SciTech Connect

    Woodson, R.D.

    1990-12-01

    An overview of current concerns in the regulation of offshore pipelines is presented along with tabulated summaries of pipeline failure causes, failure prevention techniques, and pipeline monitoring and early intervention techniques. A database of over 1000 offshore pipeline failures in the Gulf of Mexico Offshore waters has been compiled from combined records of the Department of Transportation Office of pipeline Safety, U.S. Coast Guard National Response Center, and the Department of Interior Minerals Management Service. The data has been analyzed to identify trends and initial recommendations for future data collection have been suggested.

  9. Acute liver failure in children.

    PubMed

    Devictor, Denis; Tissieres, Pierre; Afanetti, Mickael; Debray, Dominique

    2011-06-01

    The management of children with acute liver failure mandates a multidisciplinary approach and intense monitoring. In recent years, considerable progress has been made in developing specific and supportive medical measures, but clinical studies have mainly concerned adult patients. There are no specific medical therapies, except for a few metabolic diseases presenting with acute liver failure. Liver transplantation still remains the only definitive therapy in most instances. Recent clinical studies suggest that hepatocyte transplantation may be useful for bridging patients to liver transplantation, for providing metabolic support during liver failure and for replacing liver transplantation in certain metabolic liver diseases.

  10. 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... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.439 Des Allemands Bayou. (a) The draw of the S631 bridge, mile 13.9 at Des Allemands, shall open on signal if at least four hours notice...

  11. 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... DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Louisiana § 117.439 Des Allemands Bayou. (a) The draw of the S631 bridge, mile 13.9 at Des Allemands, shall open on signal if at least four hours notice...

  12. 75 FR 63714 - Drawbridge Operation Regulation; Des Allemands Bayou, LA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-18

    ... SECURITY Coast Guard 33 CFR Part 117 Drawbridge Operation Regulation; Des Allemands Bayou, LA AGENCY: Coast... Burlington Northern Santa Fe Railway swing bridge across Des Allemands Bayou, mile 14.0, in St. Charles and... INFORMATION: The Burlington Northern Santa Fe Railway swing span drawbridge across Bayou Des Allemands,...

  13. Statutes of limitations: the special problem of DES suits.

    PubMed

    Feigin, C A

    1981-01-01

    In 1971, medical studies determined that DES causes a rare type of vaginal cancer in a small number of daughters of mothers who took DES during pregnancy. Subsequently, medical studies determined that exposure to DES can cause other vaginal abnormalities in the daughters, some of which may be precancerous. As a result of these discoveries, many lawsuits have been filed by these daughters against DES manufacturers. Many DES suits may be barred by statutes of limitations, both because the number of years between the daughters' exposure to DES in utero and the discovery that DES can cause injuries exceeds the statutory period, and because the cancer or other injuries caused by DES may not develop for many additional years. This Note discusses two methods that DES plaintiffs may be able to use to overcome the potential statutes of limitations bar: the discovery rule, and state provisions which toll the statute of limitations for minors. The Note contends that courts should apply an expanded discovery rule to DES suits to avoid the unfair result of barring a claim before the plaintiff could have known that she had a cause of action. In addition, the Note argues that the injury which causes the statute of limitations to begin to run in DES suits should not be rigidly defined. Finally, the Note urges that courts allow eligible DES plaintiffs to take advantage of applicable state provisions that toll the statute of limitations for minors.

  14. 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.

  15. 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…

  16. 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.

  17. Respiratory failure in diabetic ketoacidosis

    PubMed Central

    Konstantinov, Nikifor K; Rohrscheib, Mark; Agaba, Emmanuel I; Dorin, Richard I; Murata, Glen H; Tzamaloukas, Antonios H

    2015-01-01

    Respiratory failure complicating the course of diabetic ketoacidosis (DKA) is a source of increased morbidity and mortality. Detection of respiratory failure in DKA requires focused clinical monitoring, careful interpretation of arterial blood gases, and investigation for conditions that can affect adversely the respiration. Conditions that compromise respiratory function caused by DKA can be detected at presentation but are usually more prevalent during treatment. These conditions include deficits of potassium, magnesium and phosphate and hydrostatic or non-hydrostatic pulmonary edema. Conditions not caused by DKA that can worsen respiratory function under the added stress of DKA include infections of the respiratory system, pre-existing respiratory or neuromuscular disease and miscellaneous other conditions. Prompt recognition and management of the conditions that can lead to respiratory failure in DKA may prevent respiratory failure and improve mortality from DKA. PMID:26240698

  18. Urea distribution in renal failure

    PubMed Central

    Blackmore, D. J.; Elder, W. J.; Bowden, C. H.

    1963-01-01

    An assessment of intracellular urea removed during haemodialysis has been made from urea extraction and plasma urea estimations. An apparent wide variation in the movement of intracellular urea in patients with acute renal failure from obstetric and traumatic causes and with chronic renal failure is reported. A method for the estimation of red cell water urea is presented. In two patients with chronic renal failure the red cell urea level was much higher than would have been expected from the plasma urea level before dialysis. In two obstetric patients there was no such discrepancy. The conclusion is drawn that research should be directed to variations of intracellular metabolism in renal failure before a more rational approach can be made to its management. PMID:16811009

  19. Heart failure - fluids and diuretics

    MedlinePlus

    ... Clinical Cardiology; American Heart Association Council on Nutrition, Physical Activity, and Metabolism; American Heart Association Interdisciplinary Council on Quality of Care and Outcomes Research. State of the science: promoting self-care in persons with heart failure: ...

  20. Data and Statistics: Heart Failure

    MedlinePlus

    ... this? Submit What's this? Submit Button Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ... to Prevent and Control Chronic Diseases Million Hearts® Web Sites with More Information About Heart Failure For ...

  1. How Is Respiratory Failure Treated?

    MedlinePlus

    ... Once your doctor figures out what's causing your respiratory failure, he or she will plan how to treat that disease or condition. Treatments may include medicines, procedures, and other therapies. Rate This Content: NEXT >> Updated: December 19, 2011 Twitter ...

  2. Ejection Fraction Heart Failure Measurement

    MedlinePlus

    ... 70. You can have a normal ejection fraction reading and still have heart failure (called HFpEF or ... to be made. Here we delve into the importance of shared decision making. HF Resources For Life ...

  3. Identifying Clients Predisposed To Failure

    ERIC Educational Resources Information Center

    Carnes, G. D.

    1973-01-01

    Studies are reviewed that report the prediction of rehabilitation failure from personality measures. Related research is discussed that suggest the dynamics underlying a key concept, the "hypochondriacally organized personality" which is identifiable from the Rorschach anatomy response percentage. (Author)

  4. Severe Obesity and Heart Failure

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_161011.html Severe Obesity and Heart Failure Study sees link even without ... 2016 FRIDAY, Sept. 16, 2016 (HealthDay News) -- Severe obesity appears to be an independent risk factor for ...

  5. Analyses of Transistor Punchthrough Failures

    NASA Technical Reports Server (NTRS)

    Nicolas, David P.

    1999-01-01

    The failure of two transistors in the Altitude Switch Assembly for the Solid Rocket Booster followed by two additional failures a year later presented a challenge to failure analysts. These devices had successfully worked for many years on numerous missions. There was no history of failures with this type of device. Extensive checks of the test procedures gave no indication for a source of the cause. The devices were manufactured more than twenty years ago and failure information on this lot date code was not readily available. External visual exam, radiography, PEID, and leak testing were performed with nominal results Electrical testing indicated nearly identical base-emitter and base-collector characteristics (both forward and reverse) with a low resistance short emitter to collector. These characteristics are indicative of a classic failure mechanism called punchthrough. In failure analysis punchthrough refers to an condition where a relatively low voltage pulse causes the device to conduct very hard producing localized areas of thermal runaway or "hot spots". At one or more of these hot spots, the excessive currents melt the silicon. Heavily doped emitter material diffuses through the base region to the collector forming a diffusion pipe shorting the emitter to base to collector. Upon cooling, an alloy junction forms between the pipe and the base region. Generally, the hot spot (punch-through site) is under the bond and no surface artifact is visible. The devices were delidded and the internal structures were examined microscopically. The gold emitter lead was melted on one device, but others had anomalies in the metallization around the in-tact emitter bonds. The SEM examination confirmed some anomalies to be cosmetic defects while other anomalies were artifacts of the punchthrough site. Subsequent to these analyses, the contractor determined that some irregular testing procedures occurred at the time of the failures heretofore unreported. These testing

  6. Early failure of the famous.

    PubMed

    Illingworth, R

    1986-01-01

    This is a historical review of school failure, underachievement and underestimation of the ability of children destined for world fame. Many were refused admission to a college of higher education, many failed to secure a university degree, more than 30 were expelled from school or university and several were sent to prison. Some reasons are discussed for the failure of parents and teachers to recognize outstanding ability in children.

  7. Acute hepatic failure in children.

    PubMed Central

    Riely, C. A.

    1984-01-01

    Many diseases may present as acute hepatic failure in the pediatric age group, including viral hepatitis A and B, adverse drug reactions, both toxic and "hepatitic," and inherited metabolic disorders such as tyrosinemia, alpha 1 antitrypsin deficiency, and Wilson's disease. Management is primarily supportive, with care taken to anticipate the known complications of hepatic failure. Few "curative" therapies are known, although attempts at stimulating hepatic regeneration may be helpful. Images FIG. 1 FIG. 3 FIG. 4 PMID:6433587

  8. The failure-tolerant leader.

    PubMed

    Farson, Richard; Keyes, Ralph

    2002-08-01

    "The fastest way to succeed," IBM's Thomas Watson, Sr., once said, "is to double your failure rate." In recent years, more and more executives have embraced Watson's point of view, coming to understand what innovators have always known: Failure is a prerequisite to invention. But while companies may grasp the value of making mistakes at the level of corporate practices, they have a harder time accepting the idea at the personal level. People are afraid to fail, and corporate culture reinforces that fear. In this article, psychologist and former Harvard Business School professor Richard Farson and coauthor Ralph Keyes discuss how companies can reduce the fear of miscues. What's crucial is the presence of failure-tolerant leaders--executives who, through their words and actions, help employees overcome their anxieties about making mistakes and, in the process, create a culture of intelligent risk-taking that leads to sustained innovation. Such leaders don't just accept productive failure, they promote it. Drawing from their research in business, politics, sports, and science, the authors identify common practices among failure-tolerant leaders. These leaders break down the social and bureaucratic barriers that separate them from their followers. They engage at a personal level with the people they lead. They avoid giving either praise or criticism, preferring to take a nonjudgmental, analytical posture as they interact with staff. They openly admit their own mistakes rather than trying to cover them up or shifting the blame. And they try to root out the destructive competitiveness built into most organizations. Above all else, failure-tolerant leaders push people to see beyond traditional definitions of success and failure. They know that as long as a person views failure as the opposite of success, rather than its complement, he or she will never be able to take the risks necessary for innovation. PMID:12195921

  9. Peyronie's disease and erectile failure

    SciTech Connect

    Metz, P.; Ebbehoj, J.; Uhrenholdt, A.; Wagner, G.

    1983-12-01

    A total of 20 patients with Peyronie's disease, including 15 with erectile failure and 5 with normal potency, underwent evaluation with dynamic xenon washout and infusion cavernosography. Abnormal drainage from the cavernous body was found in 13 of the 15 patients with erectile failure and in none of the 5 potent patients, indicating that this condition seems to be the underlying pathological mechanism leading to erectile impotence in patients with Peyronie's disease.

  10. [Metabolic therapy for heart failure].

    PubMed

    Loiacono, Ferdinando; Alberti, Luca; Lauretta, Ludovica; Puccetti, Patrizia; Silipigni, Carmen; Margonato, Alberto; Fragasso, Gabriele

    2014-01-01

    Heart failure may promote metabolic changes such as insulin resistance, in part through neurohumoral activation, and determining an increased utilization of non-carbohydrate substrates for energy production. In fact, fasting blood ketone bodies as well as fat oxidation have been shown to be increased in patients with heart failure. The result is depletion of myocardial ATP, phosphocreatine and creatine kinase with decreased efficiency of mechanical work. A direct approach to manipulate cardiac energy metabolism consists in modifying substrate utilization by the failing heart. To date, the most effective metabolic treatments include several pharmacological agents that directly inhibit fatty acid oxidation. The results of current research are supporting the concept that shifting the energy substrate preference away from fatty acid metabolism and toward glucose metabolism could be an effective adjunctive treatment in patients with heart failure. Trimetazidine is the most studied drug in this context. Several small studies have evidenced the usefulness of such additional therapeutic tools for heart failure. More specifically, recent meta-analyses and a multicenter retrospective study have shown that additional use of trimetazidine in patients with heart failure, along with symptoms and cardiac function improvement, also provides a significant protective effect on all-cause mortality, cardiovascular events and hospitalization due to cardiac causes. Nevertheless, the exact role of metabolic therapy in heart failure is yet to be established, and a large multicenter randomized trial is necessary. PMID:25072544

  11. Epigenetic regulation and heart failure.

    PubMed

    Cao, Dian J

    2014-09-01

    Heart failure has become a huge public health problem. The treatment options for heart failure, however, are considerably limited. The significant disparity between the scope of a prominent health problem and the restricted means of therapy propagates heart failure epidemics. Delineating novel mechanisms of heart failure is imperative. Emerging evidence suggests that epigenetic regulation may take part in the pathogenesis of heart failure. Epigenetic regulation involves DNA and histone modifications that lead to changes in DNA-based transcriptional programs without altering the DNA sequence. Although more and more mechanisms are being discovered, the best understood epigenetic modifications are achieved through covalent biochemical reactions including histone acetylation, histone methylation and DNA methylation. Connecting environmental stimuli with genomic programs, epigenetic regulation remains important in maintaining homeostases and the pathogeneses of diseases. This review summarizes the most recent developments regarding individual epigenetic modifications and their implications in the pathogenesis of heart failure. Understanding this strategically important mechanism is potentially the key for developing powerful interventions in the future.

  12. Cascaded failures in weighted networks.

    PubMed

    Mirzasoleiman, Baharan; Babaei, Mahmoudreza; Jalili, Mahdi; Safari, Mohammadali

    2011-10-01

    Many technological networks can experience random and/or systematic failures in their components. More destructive situations can happen if the components have limited capacity, where the failure in one of them might lead to a cascade of failures in other components, and consequently break down the structure of the network. In this paper, the tolerance of cascaded failures was investigated in weighted networks. Three weighting strategies were considered including the betweenness centrality of the edges, the product of the degrees of the end nodes, and the product of their betweenness centralities. Then, the effect of the cascaded attack was investigated by considering the local weighted flow redistribution rule. The capacity of the edges was considered to be proportional to their initial weight distribution. The size of the survived part of the attacked network was determined in model networks as well as in a number of real-world networks including the power grid, the internet in the level of autonomous system, the railway network of Europe, and the United States airports network. We found that the networks in which the weight of each edge is the multiplication of the betweenness centrality of the end nodes had the best robustness against cascaded failures. In other words, the case where the load of the links is considered to be the product of the betweenness centrality of the end nodes is favored for the robustness of the network against cascaded failures.

  13. Bond failure patterns in vivo.

    PubMed

    Linklater, Rognvald A; Gordon, Peter H

    2003-05-01

    The aim of this study was to identify the presence and pattern of differences in bond failure between tooth types in vivo when bonding orthodontic brackets with the no-mix orthodontic composite adhesive Right-On. In vivo bond failure for a single operator was recorded for 108 consecutive patients undergoing fixed-appliance orthodontic treatment. The bond failure data were analyzed by survival analysis. Time to first failure or censorship was recorded for each bonded attachment. Overall failure in the sample matched previous clinical studies but conflicted with previous ex vivo bond strength data. Mandibular and posterior teeth had significantly higher rates of failure than did maxillary and anterior teeth. The type of attachment used had a significant effect on bond survival. The results of this study confirm that in vivo bond survival is not uniform for all teeth. Comparisons between the findings of this study and those of a previous ex vivo study by the same authors failed to validate ex vivo bond strength testing as clinically relevant.

  14. [Competence Network Heart Failure (CNHF). Together against heart failure].

    PubMed

    Ertl, Georg; Störk, Stefan; Börste, Rita

    2016-04-01

    Heart failure is one of the most urgent medical and socio-economic challenges of the 21(st) century. Up to three million people are affected in Germany; this means one in ten people over the age of 65  live with heart failure. The current demographic changes will accentuate the importance of this grave health problem. The care of patients with heart failure, as well as the associated research mandates a comprehensive, multidisciplinary approach. The Competence Network Heart Failure (CNHF) pursues this objective. CNHF is a research alliance with 11 sites in Germany and was funded by the Federal Ministry of Research (BMBF) from 2003 through 2014. Since January 2015, the network has been an associate cooperating partner of the German Centre for Cardiovascular Research (DZHK). During the 12-year funding period by the BMBF, scientists in the field of heart failure from 30 university hospitals, 5 research institutes, 7 heart centers, 17 cardiovascular clinics, over 200 general practitioners, 4 rehabilitation clinics, as well as numerous organizations and associations were involved in cooperative CNHF research. In the context of 22 projects, the CNHF covered basic, clinical, and health care research, and generated numerous groundbreaking insights into disease mechanisms, as well as diagnosis and treatment of heart failure, which are documented in more than 350 publications. With its central study database and bank of biomaterials, the network has set up a Europe-wide unique research resource, which can be used in the future for national and international cooperations with the DZHK and other partners. Furthermore, the CNHF strongly promotes nation- and Europe-wide public relations and heart failure awareness activities. PMID:26979718

  15. 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.

  16. Genetic susceptibility to dental implant failure: a critical review.

    PubMed

    Alvim-Pereira, Fabino; Montes, Claudia C; Mira, Marcelo T; Trevilatto, Paula C

    2008-01-01

    The observation that clinical factors alone do not explain why some patients develop implant loss; the understanding of the osseointegrated implant failure as a complex, multifactorial process; and the observed aggregation of repetitive failure in certain individuals raise interesting questions related to host susceptibility to dental implant failure. Genetic analysis applied to dental implants began in the late 1990s, and since then, increased interest in genetic susceptibility to the phenotype has been demonstrated by several studies. These studies, however, have been based on and limited to candidate gene association analysis and were intended to find associations between specific alleles and/or genotypes of genetic markers and susceptibility to implant failure. The aim of this review is to provide a brief description of the current methodology for genetic analysis of complex traits, followed by a comprehensive review of the literature related to genetic susceptibility to dental implant failure and a discussion of different aspects of the applied methodology. Moreover, a novel approach of genome wide, case-control analysis is discussed as an alternative method to access genetic influence to dental implant failure mechanisms. Advances toward the elucidation of the genetic basis of dental implant loss may contribute to the understanding of why some patients do not respond to currently available treatments while others do and provide potential targets for effective screening, prevention, and treatment. For example, clinicians might be able to estimate, before the elective surgical procedure, the risk of a given patient to develop a negative individual host response. PMID:18700362

  17. Nutrition and metabolism in sepsis and multisystem organ failure.

    PubMed

    Baue, A E

    1991-06-01

    Sepsis and organ failure produce profound metabolic changes that contribute to hepatic and musculoskeletal failure. When multiple organ failure develops, the mortality rate is high, and therapy is unlikely to be effective unless the causative process (e.g., infection, low cardiac output) can be eliminated. Thus, the prevention of multiple organ failure and the prevention or early treatment of infection are paramount. Organ and nutritional support to prevent complications is necessary. The gastrointestinal tract should be used for nutrition whenever possible with a blenderized regular diet with fiber, glutamine, and short-chain fatty acids to protect and preserve the gut. If parenteral nutrition is necessary, special solutions may be necessary for the liver, kidneys, or lungs. If not, protein with 45% branched-chain amino acid, medium- and short-chain triglycerides, glutamine supplementation, and carbohydrates seem best. Other substances are being evaluated that may be helpful in nutrition and organ support, including arginine, xylitol, growth hormone, and anabolic steroids. Multiple organ failure should be prevented, if at all possible, by stopping or controlling the injury, removing as much necrotic tissue as possible, improving blood flow and oxygen consumption, supporting metabolism, and preventing infection or treating it early and adequately. Nutritional support plays a key role in preventing metabolic failure.

  18. Experimental methods for identifying failure mechanisms

    NASA Technical Reports Server (NTRS)

    Daniel, I. M.

    1983-01-01

    Experimental methods for identifying failure mechanisms in fibrous composites are studied. Methods to identify failure in composite materials includes interferometry, holography, fractography and ultrasonics.

  19. Common Cause Failures and Ultra Reliability

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2012-01-01

    A common cause failure occurs when several failures have the same origin. Common cause failures are either common event failures, where the cause is a single external event, or common mode failures, where two systems fail in the same way for the same reason. Common mode failures can occur at different times because of a design defect or a repeated external event. Common event failures reduce the reliability of on-line redundant systems but not of systems using off-line spare parts. Common mode failures reduce the dependability of systems using off-line spare parts and on-line redundancy.

  20. Using Generic Data to Establish Dormancy Failure Rates

    NASA Technical Reports Server (NTRS)

    Reistle, Bruce

    2014-01-01

    Many hardware items are dormant prior to being operated. The dormant period might be especially long, for example during missions to the moon or Mars. In missions with long dormant periods the risk incurred during dormancy can exceed the active risk contribution. Probabilistic Risk Assessments (PRAs) need to account for the dormant risk contribution as well as the active contribution. A typical method for calculating a dormant failure rate is to multiply the active failure rate by a constant, the dormancy factor. For example, some practitioners use a heuristic and divide the active failure rate by 30 to obtain an estimate of the dormant failure rate. To obtain a more empirical estimate of the dormancy factor, this paper uses the recently updated database NPRD-2011 [1] to arrive at a set of distributions for the dormancy factor. The resulting dormancy factor distributions are significantly different depending on whether the item is electrical, mechanical, or electro-mechanical. Additionally, this paper will show that using a heuristic constant fails to capture the uncertainty of the possible dormancy factors.

  1. 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

  2. Failure to thrive as a manifestation of child neglect.

    PubMed

    Block, Robert W; Krebs, Nancy F

    2005-11-01

    Failure to thrive is a common problem in infancy and childhood. It is most often multifactorial in origin. Inadequate nutrition and disturbed social interactions contribute to poor weight gain, delayed development, and abnormal behavior. The syndrome develops in a significant number of children as a consequence of child neglect. This clinical report is intended to focus the pediatrician on the consideration, evaluation, and management of failure to thrive when child neglect may be present. Child protective services agencies should be notified when the evaluation leads to a suspicion of abuse or neglect. PMID:16264015

  3. Creep failure of cracking heater at a petrochemical plant

    SciTech Connect

    El-Batahgy, A. . E-mail: elbatahgy@yahoo.com; Zaghloul, B.

    2005-03-15

    After two and half years of operation, a bend tube in a cracking heater at an ethylene plant failed due to creep cracking. Creep damage occurred as a result of metallurgical instability including coarsening of carbides that caused softening and initiation of voids or wedge-type intergranular cracks. This was accelerated due to increasing inner surface temperature during decoking process. Thermal fatigue contributed to the failure as a result of temperature variations due to several shutdown-startup operations. To minimize such failure in futures, periodic inspection to monitor crack formation was scheduled. Nondestructive tests including dye penetrant test for surface cracking and radiographic test for internal crack were implemented.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. The "Conservatoire National des Arts et Metiers"

    ERIC Educational Resources Information Center

    Kuhn, Gerard

    2004-01-01

    The overall mission of the Conservatoire national des arts et metiers--(CNAM) [National Conservatory of Industrial Arts and Trades] is outlined. One of its centers, the "Centre national de l'entrepreneuriat"--(CNE) [National Center for Entrepreneurship] is described in greater detail. In particular, this center offers various services, notably…

  10. 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.

  11. 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

  12. Pathogenesis of Multiple Organ Failure in Sepsis.

    PubMed

    Rossaint, Jan; Zarbock, Alexander

    2015-01-01

    Sepsis is a severe critical illness syndrome that arises from infectious insults. While the host immune system is generally beneficial, an overshooting and unregulated immune response can cause serious organ tissue injury. During sepsis, systemic hypotension, disturbed perfusion of the microcirculation, and direct tissue-toxicity caused by inflammatory immune reaction can occur and contribute to organ failure. The failure of two or more vital organ systems is termed multi-organ dysfunction syndrome (MODS) and resembles a very critical condition associated with high morbidity and mortality. Importantly, no specific treatment strategy exists to efficiently prevent the development of MODS during sepsis. In this review, we aim to identify the relevant molecular immunological pathways involved in the pathogenesis of MODS during sepsis. We believe that a detailed understanding of this mechanism is necessary for the development of new treatment approaches for septic patients. In particular, knowledge of the endogenous regulators keeping the balance between necessary immune system activation to combat infections and prevention of host tissue damage would greatly improve the chances for the development of effective interventions.

  13. Prognostic modeling in pediatric acute liver failure.

    PubMed

    Jain, Vandana; Dhawan, Anil

    2016-10-01

    Liver transplantation (LT) is the only proven treatment for pediatric acute liver failure (PALF). However, over a period of time, spontaneous native liver survival is increasingly reported, making us wonder if we are overtransplanting children with acute liver failure (ALF). An effective prognostic model for PALF would help direct appropriate organ allocation. Only patients who would die would undergo LT, and those who would spontaneously recover would avoid unnecessary LT. Deriving and validating such a model for PALF, however, encompasses numerous challenges. In particular, the heterogeneity of age and etiology in PALF, as well as a lack of understanding of the natural history of the disease, contributed by the availability of LT has led to difficulties in prognostic model development. Several prognostic laboratory variables have been identified, and the incorporation of these variables into scoring systems has been attempted. A reliable targeted prognostic model for ALF in Wilson's disease has been established and externally validated. The roles of physiological, immunological, and metabolomic parameters in prognosis are being investigated. This review discusses the challenges with prognostic modeling in PALF and describes predictive methods that are currently available and in development for the future. Liver Transplantation 22 1418-1430 2016 AASLD. PMID:27343006

  14. Nutrient dyshomeostasis in congestive heart failure.

    PubMed

    Kamalov, German; Holewinski, Joshua P; Bhattacharya, Syamal K; Ahokas, Robert A; Sun, Yao; Gerling, Ivan C; Weber, Karl T

    2009-07-01

    The clinical syndrome congestive heart failure (CHF) has its origins rooted in a salt-avid state mediated largely by effector hormones of the renin-angiotensin-aldosterone system. In recent years, this cardiorenal perspective of CHF has taken on a broader perspective. One which focuses on a progressive systemic illness, whose major features include the presence of oxidative stress in diverse tissues and elevated circulating levels of proinflammatory cytokines coupled with a wasting of soft tissues and bone. Experimental studies, which simulate chronic renin-angiotensin-aldosterone system activation, and translational studies in patients with salt avidity having decompensated biventricular failure with hepatic and splanchnic congestion have forged a broader understanding of this illness and the important contribution of a dyshomeostasis of Ca2+, Mg2+, Zn2+, Se2+, and vitamins D, B12, and B1. Herein, we review biomarkers indicative of the nutrient imbalance found in CHF and raise the question of a need for a polynutrient supplement in the overall management of CHF. PMID:19593100

  15. Stop sucker rod failures to save money

    SciTech Connect

    Moore, K.H.

    1981-07-01

    This study presents examples of frequent and common sucker rod failures, explains how failures occur, presents methods to recognize these failures, and discusses changes in conditions that cause failure. From early identification, corrective measures can be taken to prevent their recurrence, reducing downtime and lost production.

  16. Everyday Attention Failures: An Individual Differences Investigation

    ERIC Educational Resources Information Center

    Unsworth, Nash; McMillan, Brittany D.; Brewer, Gene A.; Spillers, Gregory J.

    2012-01-01

    The present study examined individual differences in everyday attention failures. Undergraduate students completed various cognitive ability measures in the laboratory and recorded everyday attention failures in a diary over the course of a week. The majority of attention failures were failures of distraction or mind wandering in educational…

  17. Understand Your Risk for Heart Failure

    MedlinePlus

    ... Tools & Resources Stroke More Causes and Risks for Heart Failure Updated:Jul 29,2016 Who Develops Heart Failure ( ... HF. This content was last reviewed April 2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  18. Integrated Circuit Failure Analysis Expert System

    1995-10-03

    The software assists a failure analyst performing failure anaysis on intergrated circuits. The software can also be used to train inexperienced failure analysts. The software also provides a method for storing information and making it easily available to experienced failure analysts.

  19. Integrated Circuit Failure Analysis Hypertext Help System

    1995-02-23

    This software assists a failure analyst performing failure analysis on integrated circuits. The software can also be used to train inexperienced failure analysts. The software also provides a method for storing information and making it easily available to experienced failure analysts.

  20. Failure models for textile composites

    NASA Technical Reports Server (NTRS)

    Cox, Brian

    1995-01-01

    The goals of this investigation were to: (1) identify mechanisms of failure and determine how the architecture of reinforcing fibers in 3D woven composites controlled stiffness, strength, strain to failure, work of fracture, notch sensitivity, and fatigue life; and (2) to model composite stiffness, strength, and fatigue life. A total of 11 different angle and orthogonal interlock woven composites were examined. Composite properties depended on the weave architecture, the tow size, and the spatial distributions and strength of geometrical flaws. Simple models were developed for elastic properties, strength, and fatigue life. A more complicated stochastic model, called the 'Binary Model,' was developed for damage tolerance and ultimate failure. These 3D woven composites possessed an extraordinary combination of strength, damage tolerance, and notch insensitivity.

  1. Acute Decompensated Heart Failure Update

    PubMed Central

    Teerlink, John R; Alburikan, Khalid; Metra, Marco; Rodgers, Jo E

    2015-01-01

    Acute decompensated heart failure (ADHF) continues to increase in prevalence and is associated with substantial mortality and morbidity including frequent hospitalizations. The American Heart Association is predicting that more than eight million Americans will have heart failure by 2030 and that the total direct costs associated with the disease will rise from $21 billion in 2012 to $70 billion in 2030. The increase in the prevalence and cost of HF is primarily the result of shifting demographics and a growing population. Although many large, randomized, controlled clinical trials have been conducted in patients with chronic heart failure, it was not until recently that a growing number of studies began to address the management of ADHF. It is the intent of this review to update the clinician regarding the evaluation and optimal management of ADHF. PMID:24251454

  2. [Inherited bone marrow failure syndromes].

    PubMed

    Okuno, Yusuke

    2016-02-01

    Inherited bone marrow failure syndromes comprise a series of disorders caused by various gene mutations. Genetic tests were formerly difficult to perform because of the large size and number of causative genes. However, recent advances in next-generation sequencing has enabled simultaneous testing of all causative genes to be performed at an acceptable cost. We collaboratively conducted a series of whole-exome sequencing studies of patients with inherited bone marrow failure syndromes and discovered RPS27/RPL27 and FANCT as causative genes of Diamond-Blackfan anemia and Fanconi anemia, respectively. Furthermore, we established a target gene sequencing system to cover 189 genes associated with pediatric blood diseases to assist genetic diagnoses in clinical practice. In this review, discovery of new causative genes and possible roles of next-generation sequencing in the genetic diagnosis of inherited bone marrow failure syndromes are discussed. PMID:26935625

  3. Failure models for textile composites

    SciTech Connect

    Cox, B.

    1995-08-01

    The goals of this investigation were to: (1) identify mechanisms of failure and determine how the architecture of reinforcing fibers in 3D woven composites controlled stiffness, strength, strain to failure, work of fracture, notch sensitivity, and fatigue life; and (2) to model composite stiffness, strength, and fatigue life. A total of 11 different angle and orthogonal interlock woven composites were examined. Composite properties depended on the weave architecture, the tow size, and the spatial distributions and strength of geometrical flaws. Simple models were developed for elastic properties, strength, and fatigue life. A more complicated stochastic model, called the `Binary Model,` was developed for damage tolerance and ultimate failure. These 3D woven composites possessed an extraordinary combination of strength, damage tolerance, and notch insensitivity.

  4. The pathophysiology of hypertensive acute heart failure.

    PubMed

    Viau, David M; Sala-Mercado, Javier A; Spranger, Marty D; O'Leary, Donal S; Levy, Phillip D

    2015-12-01

    While acute heart failure (AHF) is often regarded as a single disorder, an evolving understanding recognises the existence of multiple phenotypes with varied pathophysiological alterations. Herein we discuss hypertensive AHF and provide insight into a mechanism where acute fluid redistribution is caused by a disturbance in the ventricular-vascular coupling relationship. In this relationship, acute alterations in vascular elasticity, vasoconstriction and reflected pulse waves lead to increases in cardiac work and contribute to decompensated LV function with associated subendocardial ischaemia and end-organ damage. Chronic predisposing factors (neurohormonal activity, nitric oxide insensitivity, arterial stiffening) and physiological stressors (sympathetic surge, volume overload, physical exertion) that are causally linked to acute symptom onset are discussed. Lastly, we review treatment options including both nitrovasodilators and promising novel therapeutics, and discuss future directions in the management of this phenotypic variant.

  5. Catastrophic failure of ceramic-polyethylene bearing total hip arthroplasty.

    PubMed

    Needham, Justin; Burns, Travis; Gerlinger, Tad

    2008-06-01

    Complications of ceramic-polyethylene bearing total hip arthroplasty (THA) include osteolysis, loosening, dislocation, and component failure. Catastrophic acetabular component failure involves severe damage to both the polyethylene liner and metal shell. This case study presents the first reported complete wear-through of the acetabular portion of a ceramic-polyethylene arthroplasty presenting as a dislocation and a review of the literature. In this study, a patient's alumina ceramic femoral head penetrated the polyethylene liner and titanium shell and presented as a dislocated THA. The contributing factors for this catastrophic failure include young patient age, high activity level, thin polyethylene liner, backside wear, component positioning, polyethylene sterilization with gamma irradiation in air, and lack of appropriate follow-up. Revision THA was performed without complications. PMID:18514888

  6. Antibiotic failure mediated by a resistant subpopulation in Enterobacter cloacae.

    PubMed

    Band, Victor I; Crispell, Emily K; Napier, Brooke A; Herrera, Carmen M; Tharp, Greg K; Vavikolanu, Kranthi; Pohl, Jan; Read, Timothy D; Bosinger, Steven E; Trent, M Stephen; Burd, Eileen M; Weiss, David S

    2016-01-01

    Antibiotic resistance is a major public health threat, further complicated by unexplained treatment failures caused by bacteria that appear antibiotic susceptible. We describe an Enterobacter cloacae isolate harbouring a minor subpopulation that is highly resistant to the last-line antibiotic colistin. This subpopulation was distinct from persisters, became predominant in colistin, returned to baseline after colistin removal and was dependent on the histidine kinase PhoQ. During murine infection, but in the absence of colistin, innate immune defences led to an increased frequency of the resistant subpopulation, leading to inefficacy of subsequent colistin therapy. An isolate with a lower-frequency colistin-resistant subpopulation similarly caused treatment failure but was misclassified as susceptible by current diagnostics once cultured outside the host. These data demonstrate the ability of low-frequency bacterial subpopulations to contribute to clinically relevant antibiotic resistance, elucidating an enigmatic cause of antibiotic treatment failure and highlighting the critical need for more sensitive diagnostics. PMID:27572838

  7. A Comparative Study of Failure with Incremental Forming

    NASA Astrophysics Data System (ADS)

    Wu, S. H.; Song, N. N.; Pires, F. M. Andrade

    2016-08-01

    Incremental forming (ISF) is an innovative flexible sheet metal forming process which can be used to manufacture complex shapes from various materials. Due to its flexibility, it has attracted more and more attention over recent decades. Localized deformation and shear through the thickness are essential characteristics of ISF. These lead to specific failure modes and formability of ISF that are different from the conventional stamping process. In this contribution, three continuum damage models (Lemaitre, Gurson, extended GTN models) are formulated and fully coupled with the finite element simulation in a commercial software ABAQUS to predict failure in incremental forming. A comparative investigation of these three damage models has been carried out to analyze both the deformation behavior and failure mechanisms.

  8. Cell cycle regulation: repair and regeneration in acute renal failure.

    PubMed

    Price, Peter M; Megyesi, Judit; Safirstein, Robert L

    2003-09-01

    Research into mechanisms of acute renal failure has begun to reveal molecular targets for possible therapeutic intervention. Much useful knowledge into the causes and prevention of this syndrome has been gained by the study of animal models. Most recently, investigation of the effects on acute renal failure of selected gene knock-outs in mice has contributed to our recognition of many previously unappreciated molecular pathways. Particularly, experiments have revealed the protective nature of 2 highly induced genes whose functions are to inhibit and control the cell cycle after acute renal failure. By use of these models we have started to understand the role of increased cell cycle activity after renal stress and the role of proteins induced by these stresses that limit this proliferation.

  9. Cell cycle regulation: repair and regeneration in acute renal failure.

    PubMed

    Price, Peter M; Megyesi, Judit; Saf Irstein, Robert L

    2004-08-01

    Research into mechanisms of acute renal failure has begun to reveal molecular targets for possible therapeutic intervention. Much useful knowledge into the causes and prevention of this syndrome has been gained by the study of animal models. Most recently, investigation of the effects on acute renal failure of selected gene knock-outs in mice has contributed to our recognition of many previously unappreciated molecular pathways. Particularly, experiments have revealed the protective nature of two highly induced genes whose functions are to inhibit and control the cell cycle after acute renal failure. By use of these models we have started to understand the role of increased cell cycle activity after renal stress, and the role of proteins induced by these stresses that limit this proliferation.

  10. Heart failure: SGLT2 inhibitors and heart failure -- clinical implications.

    PubMed

    Raz, Itamar; Cahn, Avivit

    2016-04-01

    The latest findings from the EMPA-REG OUTCOME trial show a 34% reduction in hospitalization for heart failure or cardiovascular death in patients receiving empagliflozin, a sodium/glucose cotransporter 2 (SGLT2) inhibitor, compared with placebo. These outstanding results call for discussion of the clinical implications, and in-depth studies of the mechanisms of action of SGLT2 inhibitors.

  11. Heart failure in African Americans.

    PubMed

    Yancy, Clyde W

    2005-10-10

    The demographics of the United States are changing, and in the next few decades there will no longer be a racial/ethnic majority population. Increased awareness of cardiovascular disease (CVD) in special populations is warranted as these populations increase. Heart failure carries a substantial burden on those affected, particularly African Americans, who have a disproportionate burden of heart disease. Current treatments for heart failure include angiotensin-converting enzyme inhibitors, beta-blockers, angiotensin II-receptor antagonists, and vasodilating agents. This review discusses the unique characteristics of CVD in African Americans and addresses the need for targeted treatments to reduce the excess burden found in this population.

  12. Redesign overcomes electrode hammer failures

    SciTech Connect

    Roberts, R.; Necessary, J.; Spond, D. )

    1992-06-01

    This paper reports that growing numbers of collection electrode (CE) hammer failures challenged Arkansas Power and Light Co. (AP and L) engineers recently during their studies of electrostatic precipitator (ESP) incidents. Failed hammers eventually cause opacity compliance violations. Quick response was deemed necessary. During an August, 1989, inspection of the precipitator, plant engineers found pieces of CE hammers in the inlet field of A box. Findings showed that failures resulted form reverse bending fatigue, which was caused by repetitive impact loads on these low alloy steel castings.

  13. Diastolic Function in Heart Failure

    PubMed Central

    Kovács, Sándor J

    2015-01-01

    Heart failure has reached epidemic proportions, and diastolic heart failure or heart failure with preserved ejection fraction (HFpEF) constitutes about 50% of all heart failure admissions. Long-term prognosis of both reduced ejection fraction heart failure and HFpEF are similarly dismal. No pharmacologic agent has been developed that actually treats or repairs the physiologic deficit(s) responsible for HFpEF. Because the physiology of diastole is both subtle and counterintuitive, its role in heart failure has received insufficient attention. In this review, the focus is on the physiology of diastole in heart failure, the dominant physiologic laws that govern the process in all hearts, how all hearts work as a suction pump, and, therefore, the elucidation and characterization of what actually is meant by “diastolic function”. The intent is for the reader to understand what diastolic function actually is, what it is not, and how to measure it. Proper measurement of diastolic function requires one to go beyond the usual E/A, E/E′, etc. phenomenological metrics and employ more rigorous causality (mathematical modeling) based parameters of diastolic function. The method simultaneously provides new physiologic insight into the meaning of in vivo “equilibrium volume” of the left ventricle (LV), longitudinal versus transverse volume accommodation of the chamber, diastatic “ringing” of the mitral annulus, and the mechanism of L-wave generation, as well as availability of a load-independent index of diastolic function (LIIDF). One important consequence of understanding what diastolic function is, is the recognition that all that current therapies can do is basically alter the load, rather than actually “repair” the functional components (chamber stiffness, chamber relaxation). If beneficial (biological/structural/metabolic) remodeling due to therapy does manifest ultimately as improved diastolic function, it is due to resumption of normal physiology (as in

  14. Graphical Displays Assist In Analysis Of Failures

    NASA Technical Reports Server (NTRS)

    Pack, Ginger; Wadsworth, David; Razavipour, Reza

    1995-01-01

    Failure Environment Analysis Tool (FEAT) computer program enables people to see and better understand effects of failures in system. Uses digraph models to determine what will happen to system if set of failure events occurs and to identify possible causes of selected set of failures. Digraphs or engineering schematics used. Also used in operations to help identify causes of failures after they occur. Written in C language.

  15. A simple approach to modeling ductile failure.

    SciTech Connect

    Wellman, Gerald William

    2012-06-01

    Sandia National Laboratories has the need to predict the behavior of structures after the occurrence of an initial failure. In some cases determining the extent of failure, beyond initiation, is required, while in a few cases the initial failure is a design feature used to tailor the subsequent load paths. In either case, the ability to numerically simulate the initiation and propagation of failures is a highly desired capability. This document describes one approach to the simulation of failure initiation and propagation.

  16. 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

  17. 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.

  18. Statins and oxidative stress in chronic heart failure.

    PubMed

    Costa, Sónia; Reina-Couto, Marta; Albino-Teixeira, António; Sousa, Teresa

    2016-01-01

    Statins are the most commonly prescribed drugs for the treatment of dyslipidemia. They are also recommended in primary and secondary prevention of cardiovascular disease. In addition to decreasing cholesterol synthesis, statins interfere with the synthesis of isoprenoid intermediates, which may explain many of their pleiotropic properties, including their antioxidant effects. Oxidative stress is defined as an imbalance between the synthesis of reactive oxygen species and their elimination by antioxidant defense systems, with a prevailing pro-oxidant status that results in macromolecular damage and disruption of cellular redox signaling. Reactive oxygen species interfere with various processes that affect cardiac structure and function, contributing to the contractile dysfunction, myocardial hypertrophy and fibrosis observed in the pathophysiology of heart failure. By regulating several molecular pathways that control nicotinamide adenine dinucleotide phosphate oxidase and endothelial nitric oxide synthase activity, statins help restore redox homeostasis. These drugs also contribute to the control of inflammation and appear to have a protective role in various diseases. The results of observational studies and clinical trials with statins in heart failure have not been consensual. This review aims to analyze the role of oxidative stress in heart failure and the molecular mechanisms underlying statins' antioxidant properties. It also examines current scientific evidence on the use of these drugs as a specific treatment for heart failure.

  19. 3D statistical failure analysis of monolithic dental ceramic crowns.

    PubMed

    Nasrin, Sadia; Katsube, Noriko; Seghi, Robert R; Rokhlin, Stanislav I

    2016-07-01

    For adhesively retained ceramic crown of various types, it has been clinically observed that the most catastrophic failures initiate from the cement interface as a result of radial crack formation as opposed to Hertzian contact stresses originating on the occlusal surface. In this work, a 3D failure prognosis model is developed for interface initiated failures of monolithic ceramic crowns. The surface flaw distribution parameters determined by biaxial flexural tests on ceramic plates and point-to-point variations of multi-axial stress state at the intaglio surface are obtained by finite element stress analysis. They are combined on the basis of fracture mechanics based statistical failure probability model to predict failure probability of a monolithic crown subjected to single-cycle indentation load. The proposed method is verified by prior 2D axisymmetric model and experimental data. Under conditions where the crowns are completely bonded to the tooth substrate, both high flexural stress and high interfacial shear stress are shown to occur in the wall region where the crown thickness is relatively thin while high interfacial normal tensile stress distribution is observed at the margin region. Significant impact of reduced cement modulus on these stress states is shown. While the analyses are limited to single-cycle load-to-failure tests, high interfacial normal tensile stress or high interfacial shear stress may contribute to degradation of the cement bond between ceramic and dentin. In addition, the crown failure probability is shown to be controlled by high flexural stress concentrations over a small area, and the proposed method might be of some value to detect initial crown design errors. PMID:27215334

  20. 3D statistical failure analysis of monolithic dental ceramic crowns.

    PubMed

    Nasrin, Sadia; Katsube, Noriko; Seghi, Robert R; Rokhlin, Stanislav I

    2016-07-01

    For adhesively retained ceramic crown of various types, it has been clinically observed that the most catastrophic failures initiate from the cement interface as a result of radial crack formation as opposed to Hertzian contact stresses originating on the occlusal surface. In this work, a 3D failure prognosis model is developed for interface initiated failures of monolithic ceramic crowns. The surface flaw distribution parameters determined by biaxial flexural tests on ceramic plates and point-to-point variations of multi-axial stress state at the intaglio surface are obtained by finite element stress analysis. They are combined on the basis of fracture mechanics based statistical failure probability model to predict failure probability of a monolithic crown subjected to single-cycle indentation load. The proposed method is verified by prior 2D axisymmetric model and experimental data. Under conditions where the crowns are completely bonded to the tooth substrate, both high flexural stress and high interfacial shear stress are shown to occur in the wall region where the crown thickness is relatively thin while high interfacial normal tensile stress distribution is observed at the margin region. Significant impact of reduced cement modulus on these stress states is shown. While the analyses are limited to single-cycle load-to-failure tests, high interfacial normal tensile stress or high interfacial shear stress may contribute to degradation of the cement bond between ceramic and dentin. In addition, the crown failure probability is shown to be controlled by high flexural stress concentrations over a small area, and the proposed method might be of some value to detect initial crown design errors.

  1. Polyhydramnios and acute renal failure

    PubMed Central

    Hamilton, D. V.; Kelly, Moira B.; Pryor, J. S.

    1980-01-01

    Acute renal failure secondary to ureteric obstruction is described in a primigravida with twin gestation and polyhydramnios. Relief of the obstruction occurred on drainage of the liquor and return to normal renal function following delivery. ImagesFig. 1 PMID:7022419

  2. Nonresident Fathering and School Failure

    ERIC Educational Resources Information Center

    Menning, Chadwick L.

    2006-01-01

    Does involvement by nonresident fathers affect adolescents' propensity to remain in school? If so, is some involvement necessarily better than none, and are changes in involvement with time associated with changes in the odds of school failure? What aspects of involvement matter the most? This study uses data from the National Longitudinal Study…

  3. Failure Is Always an Option

    ERIC Educational Resources Information Center

    Chudnov, Daniel

    2008-01-01

    Things are failing everywhere. A few years ago, several large companies disappeared almost overnight in a series of scandals. This year, the mortgage industry imploded. More recently, stalwart financial and insurance corporations have been dropping like flies. Failures happen on a smaller scale too. Recently, the all-caps word "FAIL" became a…

  4. Skin Failure: An Emerging Concept.

    PubMed

    Levine, Jeffrey M

    2016-07-01

    Skin failure is an emerging concept that clarifies trends in clinical practice. Its recognition provides common nomenclature, opens research directions, and questions assumptions regarding pressure ulcers as a quality measure. Adoption of the term is a step toward uniform terminology in compliance with a value based payment system.

  5. Children's Coping with Academic Failure

    ERIC Educational Resources Information Center

    Raftery-Helmer, Jacquelyn N.; Grolnick, Wendy S.

    2016-01-01

    There is little consensus on how to conceptualize coping after perceived failure and less is known about the contextual resources that may support or undermine the use of specific coping strategies. This study examined parenting in relation to coping using the framework of self-determination theory and examined the motivational processes through…

  6. Failure rate analysis using GLIMMIX

    SciTech Connect

    Moore, L.M.; Hemphill, G.M.; Martz, H.F.

    1998-12-01

    This paper illustrates use of a recently developed SAS macro, GLIMMIX, for implementing an analysis suggested by Wolfinger and O`Connell (1993) in modeling failure count data with random as well as fixed factor effects. Interest in this software tool arose from consideration of modernizing the Failure Rate Analysis Code (FRAC), developed at Los Alamos National Laboratory in the early 1980`s by Martz, Beckman and McInteer (1982). FRAC is a FORTRAN program developed to analyze Poisson distributed failure count data as a log-linear model, possibly with random as well as fixed effects. These statistical modeling assumptions are a special case of generalized linear mixed models, identified as GLMM in the current statistics literature. In the nearly 15 years since FRAC was developed, there have been considerable advances in computing capability, statistical methodology and available statistical software tools allowing worthwhile consideration of the tasks of modernizing FRAC. In this paper, the approaches to GLMM estimation implemented in GLIMMIX and in FRAC are described and a comparison of results for the two approaches is made with data on catastrophic time-dependent pump failures from a report by Martz and Whiteman (1984). Additionally, statistical and graphical model diagnostics are suggested and illustrated with the GLIMMIX analysis results.

  7. Leveraging Failure in Design Research

    ERIC Educational Resources Information Center

    Lobato, Joanne; Walters, C. David; Hohensee, Charles; Gruver, John; Diamond, Jaime Marie

    2015-01-01

    Even in the resource-rich, more ideal conditions of many design-based classroom interventions, unexpected events can lead to disappointing results in student learning. However, if later iterations in a design research study are more successful, the previous failures can provide opportunities for comparisons to reveal subtle differences in…

  8. Development of GENOA Progressive Failure Parallel Processing Software Systems

    NASA Technical Reports Server (NTRS)

    Abdi, Frank; Minnetyan, Levon

    1999-01-01

    A capability consisting of software development and experimental techniques has been developed and is described. The capability is integrated into GENOA-PFA to model polymer matrix composite (PMC) structures. The capability considers the physics and mechanics of composite materials and structure by integration of a hierarchical multilevel macro-scale (lamina, laminate, and structure) and micro scale (fiber, matrix, and interface) simulation analyses. The modeling involves (1) ply layering methodology utilizing FEM elements with through-the-thickness representation, (2) simulation of effects of material defects and conditions (e.g., voids, fiber waviness, and residual stress) on global static and cyclic fatigue strengths, (3) including material nonlinearities (by updating properties periodically) and geometrical nonlinearities (by Lagrangian updating), (4) simulating crack initiation. and growth to failure under static, cyclic, creep, and impact loads. (5) progressive fracture analysis to determine durability and damage tolerance. (6) identifying the percent contribution of various possible composite failure modes involved in critical damage events. and (7) determining sensitivities of failure modes to design parameters (e.g., fiber volume fraction, ply thickness, fiber orientation. and adhesive-bond thickness). GENOA-PFA progressive failure analysis is now ready for use to investigate the effects on structural responses to PMC material degradation from damage induced by static, cyclic (fatigue). creep, and impact loading in 2D/3D PMC structures subjected to hygrothermal environments. Its use will significantly facilitate targeting design parameter changes that will be most effective in reducing the probability of a given failure mode occurring.

  9. 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

  10. On the failure of distractor inhibition in the attentional blink.

    PubMed

    Dux, Paul E; Harris, Irina M

    2007-08-01

    We investigated whether a failure of distractor inhibition contributes to the magnitude of the attentional blink (AB). Subjects viewed dual-target rapid serial visual presentation (RSVP) streams, where the distractors that directly preceded and succeeded Target 2 (T2-1, T2+ 1) were either identical to each other or different. Previously, Dux, Coltheart, and Harris (2006) found enhanced target report in RSVP due to repetition of distractors around Target 1, which was interpreted as evidence of distractor inhibition. Here, distractor repetition again attenuated the AB, but only at lag 2, the Target 2 position where T2-1 would have undergone attentive processing. Our results demonstrate that the distractor repetition effect is dependent on attention, and that a failure to inhibit distractors contributes to the AB.

  11. Pathophysiology and clinical evaluation of acute heart failure.

    PubMed

    Mentz, Robert J; O'Connor, Christopher M

    2016-01-01

    Acute heart failure (AHF) is a complex syndrome characterized by worsening heart failure (HF) symptoms that requires escalation of therapy. Intrinsic cardiac abnormalities and comorbid conditions, including lung and renal disease, and sleep-disordered breathing, can contribute to the development of AHF. In this Review, we summarize and discuss the literature on the clinical evaluation and underlying pathophysiology of AHF. Important features of AHF evaluation include identification of precipitating factors to the disease, and assessment of circulatory-renal limitations associated with use of HF medications, prior HF hospitalizations, congestion and perfusion profiles, and end-organ dysfunction. The pathophysiological contributions of endothelial dysfunction, neurohormonal activation, venous congestion, and myocardial injury to the development of AHF are also discussed. These potential causative mechanisms provide a framework for clinicians to evaluate and manage patients with AHF and highlight possible future targets for therapies designed to improve clinical outcomes.

  12. Genetics Home Reference: action myoclonus-renal failure syndrome

    MedlinePlus

    ... Action Myoclonus - Renal Failure Syndrome Genetic Testing Registry: Epilepsy, progressive myoclonic 4, with or without renal failure ... failure syndrome action myoclonus–renal failure syndrome AMRF epilepsy, progressive myoclonic 4, with or without renal failure ...

  13. Étude des déplacements induits par des précipités dans des alliages à base de cuivre

    NASA Astrophysics Data System (ADS)

    Guillon, I.; Servant, C.; Lyon, O.

    2004-11-01

    Cette étude a pour but de mieux comprendre les premières étapes des phénomènes se produisant lors de la formation de nanoprécipités. En effet, la microstructure des alliages conditionne leurs propriétés mécaniques, et donc l'emploi de ces matériaux. Alors que l'anisotropie des déformations élastiques permet d'expliquer la morphologie des précipités formés lors des traitements thermiques de revenu, peu d'études se sont attachées à les déterminer expérimentalement. Mots clés : transformations de phases, diffusion/diffraction, synchrotron, alliages à base Cu, déplacements

  14. Mechanisms of heart failure in obesity.

    PubMed

    Ebong, Imo A; Goff, David C; Rodriguez, Carlos J; Chen, Haiying; Bertoni, Alain G

    2014-01-01

    Heart failure is a leading cause of morbidity and mortality and its prevalence continues to rise. Because obesity has been linked with heart failure, the increasing prevalence of obesity may presage further rise in heart failure in the future. Obesity-related factors are estimated to cause 11% of heart failure cases in men and 14% in women. Obesity may result in heart failure by inducing haemodynamic and myocardial changes that lead to cardiac dysfunction, or due to an increased predisposition to other heart failure risk factors. Direct cardiac lipotoxicity has been described where lipid accumulation in the heart results in cardiac dysfunction inexplicable of other heart failure risk factors. In this overview, we discussed various pathophysiological mechanisms that could lead to heart failure in obesity, including the molecular mechanisms underlying cardiac lipotoxicity. We defined the obesity paradox and enumerated various premises for the paradoxical associations observed in the relationship between obesity and heart failure.

  15. 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

  16. Caractérisation des technologies IR au CELAR

    NASA Astrophysics Data System (ADS)

    Burgaud, Pierre; Moreau, Christian; Ruelloux, Daniel

    2003-12-01

    In this paper, we described the Infrared technologies (MCT, QWIP and microbolometers) characterization carried out by CELAR, in addition to the Electro-Optical (EO) characterization driven by ONERA, both backing up service programs of the French National Armaments Organization (DGA). After a brief description of the methodology and tools used, some results are given in order to show the construction and failure analysis contributions in the correlation of EO defects to visual defects and also, in the quality and preventive reliability improvements for these IR technologies, for a better satisfaction of the military end-users needs. To cite this article: P. Burgaud et al., C. R. Physique 4 (2003).

  17. 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.

  18. Interventions for heart failure readmissions: successes and failures.

    PubMed

    Fleming, Lisa M; Kociol, Robb D

    2014-06-01

    Heart failure readmissions result in significant costs to the health care system and to patients' quality of life, but programs to reduce readmissions have met with mixed success. Successful strategies have included multidisciplinary hospital-based quality initiatives, disease management programs, and care transition interventions. Devices like telemonitors and indwelling catheters, however, have met with mixed success. Research is still needed to elucidate the most effective interventions for readmission reduction in the HF population.

  19. 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

  20. 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

  1. 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

  2. Profil anthropometrique des enfants scolarises tananariviens

    PubMed Central

    Razafimanantsoa, Fetralinjiva; Razafindramaro, Notahiana; Raherimandimby, Hasina; Robinson, Annick; RakotoAlson, Olivat; Rasamindrakotroka, Andry

    2013-01-01

    Les enfants tananariviens sont en état de malnutrition chronique. Notre objectif est d’évaluer l'indice de masse corporelle (IMC) pour estimer les enfants apparemment "sains". Une enquête et une mesure de la taille et du poids des enfants scolarisés tananariviens de 6 à 11 ans ont été réalisées. Après leur accord, la taille et l'indice de masse corporelle des 442 enfants tirés au hasard ont été ainsi obtenus. L'analyse de la moyenne de la taille a révélé une différence significative à 8 ans, une différence non évidente sur l'indice de masse corporelle. La comparaison avec les valeurs de référence (OMS 2006) a montré un retard statural de 34% avec une tendance globale à la hausse et un déficit pondéral égal à 5,5% selon le z score. Ainsi, au sein d'une population malnutrie, l'indice de masse corporelle pourrait être utilisé comme un des paramètres à considérer dans l’évaluation de l’état de santé pour classer ces enfants en bonne santé apparente. PMID:24711862

  3. 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).

  4. Sécurité au-delà des mythes et des croyances

    SciTech Connect

    2010-06-24

    Présentation orale en français, support visuel en français et en anglais. La pire des failles de sécurité est l'impression de sécurité. Le décalage entre la compréhension que l’on a des technologies utilisées, et leurs potentiels réels, ainsi que l'impact potentiellement négatif qu'elles peuvent avoir sur nos vies, n'est pas toujours compris, ou pris en compte par la plupart d'entre-nous. On se contente de nos perceptions pour ne pas avoir à se confronter à la réalité... Alors qu'en est-il vraiment ? En matière de sécurité qui de l'humain ou des technologies a le contrôle ?

  5. 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

  6. 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

  7. Disastrous events and political failures.

    PubMed

    Levett, Jeffrey

    2015-06-01

    Response to the Ebola crisis (ongoing event) has been less than efficient. It has been monitored less than adequately by the international community and has been coordinated poorly in the USA. The event is used as a platform to examine deficiencies in public health infrastructure, the limits of its political and financial support, and how political outcomes can be affected. The need to tease out the political determinants implicit in policy failure and disaster management is argued in this Editorial. Failures mentioned include in the Balkans and in Greece with ongoing austerity. Comments on the real heroes of Ebola on the ground in Africa and the need for a charismatic role for political leaders in public health are also included. PMID:25882131

  8. Red eyes in renal failure.

    PubMed Central

    Klaassen-Broekema, N; van Bijsterveld, O P

    1992-01-01

    Of 57 patients with chronic renal failure who all had deposition of calcium salts in the conjunctival and corneal tissue two developed a brief episode of painful irritation and redness of the conjunctiva and subconjunctiva. This hyperaemia was adjacent to erosions of the corneal epithelium of the eye as a consequence of exfoliation of calcium concretions from the superficial corneal epithelium. Eight patients showed inflammatory reactions of the conjunctivae that were clinically identical to inflamed pingueculae. Three patients showed an inflammatory reaction of the eye that was characterised by a waxy red, more or less diffuse, episcleral and conjunctival hyperaemia extending beyond the palpebral fissure. The average value of the serum calcium concentration in these patients was particularly high and statistically significantly higher than in patients with calcification but without inflammatory signs and also higher than in patients who showed pingueculitis. We propose to reserve the term 'red eye of renal failure' for the latter group of patients. Images PMID:1390507

  9. Disastrous events and political failures.

    PubMed

    Levett, Jeffrey

    2015-06-01

    Response to the Ebola crisis (ongoing event) has been less than efficient. It has been monitored less than adequately by the international community and has been coordinated poorly in the USA. The event is used as a platform to examine deficiencies in public health infrastructure, the limits of its political and financial support, and how political outcomes can be affected. The need to tease out the political determinants implicit in policy failure and disaster management is argued in this Editorial. Failures mentioned include in the Balkans and in Greece with ongoing austerity. Comments on the real heroes of Ebola on the ground in Africa and the need for a charismatic role for political leaders in public health are also included.

  10. ATM CMG bearing failure analysis

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The cause or causes for the failure of ATM CMG S/N 5 (Skylab 1) and the anomalies associated with ATM CMG S/N 6 (Skylab 2) were investigated. Skylab telemetry data were reviewed and presented in the form of parameter distributions. The theory that the problems were caused by marginal bearing lubrication was studied along with the effects of orbital conditions on lubricants. Bearing tests were performed to investigate the effect of lubricant or lack of lubricant in the ATM CMG bearings and the dispersion and migration of the lubricant. The vacuum and weightless conditions of space were simulated in the bearing tests. Analysis of the results of the tests conducted points to inadequate lubrication as the predominant factor causing the failure of ATM CMG S/N 5 (Skylab 1) and the anomalies associated with ATM CMG S/N 6 (Skylab 2).

  11. SYNTHETIC SLING FAILURE - EVALUATIONS & RECOMMENDATIONS

    SciTech Connect

    MACKEY TC; HENDERSON CS

    2009-10-26

    The information and evaluations provided in this report were compiled to address the recurring problem of synthetic sling failure. As safety is the number one priority in all work aspects, a solution must be devised to prevent accidents from occurring. A total of thirteen cases regarding synthetic sling failure were evaluated in order to determine their causes, effects, and preventative measures. From the collected data, it was found that all cases in which the synthetic sling contacted the edge of its load resulted in sling failure. It is required that adequate synthetic sling protection devices be used to protect slings in any lift where the sling comes in direct contact with the edge or corner of its load. However, there are no consensus codes or standards stating the type, material, or purpose of the type of protective device used to protect the sling from being cut. Numerous industry standards and codes provide vague descriptions on how to protect synthetic slings. Without a clear, concise statement of how to protect synthetic slings, it is common for inadequate materials and sling protection devices to be used in an attempt to meet the intent of these requirements. The use of an inadequate sling protection device is the main cause of synthetic sling failure in all researched cases. Commercial sling protection devices come in many shapes and sizes, and have a variety of names, as well as advertised uses. 'Abrasion pads' and 'wear protectors' are two different names for products with the same intended purpose. There is no distinguishable way to determine the extent of sling protection which these devices will provide, or what specific scenarios they are made for. This creates room for error in a field where error is unacceptable. This report provides a recommended action for hoisting and rigging activities which require synthetic slings to contact a load, as well as recommended changes to industry standards which will benefit overall industry safety.

  12. [Reactor safety and human failure].

    PubMed

    Smidt, D

    1979-12-01

    Reactor safety is given by the reliable solution of 3 tasks: on-time shutdown, continuous decay-heat removal, safe containment. After describing the general strategy of their solution even under upset conditions the most important engineered safeguards of pressurized water reactors are summarized. The important problem of human failure is discussed in some more detail. For the example Harrisburg some difficulties, but also some technical countermeasures are illustrated. PMID:537639

  13. Multiaxial failure characterization of composites

    SciTech Connect

    Groves, S.E.; Sanchez, R.J.; Feng, W.W.

    1991-02-01

    The primary objective of this research has been to develop a multiaxial testing capability for continuous fiber composites using the axial/torsion/internal pressurization of tubes. This capability enables one to generate the two-dimensional (in-plane) failure surface for these materials. The multiaxial test specimen consists of a 5.08 cm (2.0 in.) diameter composite tube with 15{degrees} cast epoxy end cones for gripping. The unique advancement with this new technique is the simple, but very efficient, gripping mechanism that provides a very smooth transition in load from the grip into the specimen. This has eliminated grip related stress risers in the composite tube. Consequently, most of the failures occur in the gage section of the tube. This system is coupled into a biaxial MTS servo hydraulic test machine capable of simultaneously applying axial load, torque, and internal pressure, providing one complete control of the axial, transverse, and shear stresses that develop in the wall of the composite tube. This paper will present the failure results obtained to date for various laminate configurations of Toray 1000/DER332-T403 filament wound carbon/epoxy tubes along with T300/F263 prepreg carbon/epoxy tubes. The goal of our efforts is to develop a more fully characterized three-dimensional failure criterion for these materials. This model will then be incorporated into a large three-dimensional orthotropic finite element model for structural analysis as well as a specialized three-dimensional orthotropic finite element model capable of detailed sub-ply level analysis on sub-structural components. 19 refs., 10 figs.

  14. Accountability for network backup failures

    SciTech Connect

    Benson, W.H.

    1994-02-01

    Regular hard disk backups for workstations are widely recommended. The necessity of backups -- akin to one`s own mortality -- is something most people would rather not think about. This attitude has two consequences. When people do subscribe to automated network backups, they expect the system to perform at a high level of reliability and that their files will be there for them when they need them. Second, they usually fail to appreciate that reliability is a shared responsibility. Although ostensibly their only responsibility is to keep the computer powered on overnight, there are actually many more opportunities for failure within the user`s jurisdiction than in other parts of the infrastructure. High reliability is almost a sine qua non for backups. We describe a strategy for enhancing reliability based on the principle of accountability. This strategy involves monitoring the system, gathering statistics, detecting problems, anticipating problems, troubleshooting, and finally determining where failure occurred within the infrastructure and who should be accountable. We describe a specific backup system in a specific network environment to illustrate the value of accountability. This system, macdumps, backs up Macintosh disks over an AppleTalk network. The original software was written by Dan Tappan of BBN in the early years of the Mac and is available by ftp for noncommercial use. It has proven reliable and robust. Despite the high quality of the fundamental software, there are still many opportunities for failure within the infrastructure. We first discuss accountability in the context of network backups, then briefly describe how the backup system operates, the components of the infrastructure, types of failures experienced, and then summarize our experience.

  15. Outpatient treatment of heart failure.

    PubMed

    McConaghy, John R; Smith, Steven R

    2002-06-01

    Heart failure (HF) affects more than 2 million adults in the United States. This common, costly, and disabling disorder mainly affects the elderly, with prevalence rates up to 10% in patients older than 65 years. The management of HF is responsible for millions of outpatient visits per year, is the most common discharge diagnosis for Medicare beneficiaries, and accounts for more than 5% of total health care dollars spent.

  16. Detecting failure of climate predictions

    USGS Publications Warehouse

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-01-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty1, 2. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies3. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  17. Detecting failure of climate predictions

    NASA Astrophysics Data System (ADS)

    Runge, Michael C.; Stroeve, Julienne C.; Barrett, Andrew P.; McDonald-Madden, Eve

    2016-09-01

    The practical consequences of climate change challenge society to formulate responses that are more suited to achieving long-term objectives, even if those responses have to be made in the face of uncertainty. Such a decision-analytic focus uses the products of climate science as probabilistic predictions about the effects of management policies. Here we present methods to detect when climate predictions are failing to capture the system dynamics. For a single model, we measure goodness of fit based on the empirical distribution function, and define failure when the distribution of observed values significantly diverges from the modelled distribution. For a set of models, the same statistic can be used to provide relative weights for the individual models, and we define failure when there is no linear weighting of the ensemble models that produces a satisfactory match to the observations. Early detection of failure of a set of predictions is important for improving model predictions and the decisions based on them. We show that these methods would have detected a range shift in northern pintail 20 years before it was actually discovered, and are increasingly giving more weight to those climate models that forecast a September ice-free Arctic by 2055.

  18. Predicting Electronic Failure from Smoke

    SciTech Connect

    Tanaka, T.J.

    1999-01-15

    Smoke can cause electronic equipment to fail through increased leakage currents and shorts. Sandia National Laboratories is studying the increased leakage currents caused by smoke with varying characteristics. The objective is to develop models to predict the failure of electronic equipment exposed to smoke. This requires the collection of data on the conductivity of smoke and knowledge of critical electrical systems that control high-consequence operations. We have found that conductivity is a function of the type of fuel, how it is burned, and smoke density. Video recordings of highly biased dc circuits exposed in a test chamber show that during a fire, smoke is attracted to high voltages and can build fragile carbon bridges that conduct leakage currents. The movement of air breaks the bridges, so the conductivity decreases after the fire is extinguished and the test chamber is vented. During the fire, however, electronic equipment may not operate correctly, leading to problems for critical operations dependent on electronic control. The potential for electronic failure is highly dependent on the type of electrical circuit, and Sandia National Laboratories plans to include electrical circuit modeling in the failure models.

  19. Model for heart failure education.

    PubMed

    Baldonado, Analiza; Dutra, Danette; Abriam-Yago, Katherine

    2014-01-01

    Heart failure (HF) is the heart's inability to meet the body's need for blood and oxygen. According to the American Heart Association 2013 update, approximately 5.1 million people are diagnosed with HF in the United States in 2006. Heart failure is the most common diagnosis for hospitalization. In the United States, the HF direct and indirect costs are estimated to be US $39.2 billion in 2010. To address this issue, nursing educators designed innovative teaching frameworks on HF management both in academia and in clinical settings. The model was based on 2 resources: the American Association of Heart Failure Nurses (2012) national nursing certification and the award-winning Pierce County Responsive Care Coordination Program. The HF educational program is divided into 4 modules. The initial modules offer foundational levels of Bloom's Taxonomy then progress to incorporate higher-levels of learning when modules 3 and 4 are reached. The applicability of the key components within each module allows formatting to enhance learning in all areas of nursing, from the emergency department to intensive care units to the medical-surgical step-down units. Also applicable would be to provide specific aspects of the modules to nurses who care for HF patients in skilled nursing facility, rehabilitation centers, and in the home-health care setting. PMID:25140745

  20. Acylated but not des-acyl ghrelin is neuroprotective in an MPTP mouse model of Parkinson's disease.

    PubMed

    Bayliss, Jacqueline A; Lemus, Moyra; Santos, Vanessa V; Deo, Minh; Elsworth, John D; Andrews, Zane B

    2016-05-01

    The gut hormone ghrelin is widely beneficial in many disease states. However, ghrelin exists in two distinctive isoforms, each with its own metabolic profile. In Parkinson's Disease (PD) acylated ghrelin administration is neuroprotective, however, the role of des-acylated ghrelin remains unknown. In this study, we wanted to identify the relative contribution each isoform plays using the MPTP model of PD. Chronic administration of acylated ghrelin in mice lacking both isoforms of ghrelin (Ghrelin KO) attenuated the MPTP-induced loss on tyrosine hydroxylase (TH) neuronal number and volume and TH protein expression in the nigrostriatal pathway. Moreover, acylated ghrelin reduced the increase in glial fibrillary acidic protein and Ionized calcium binding adaptor molecule 1 microglia in the substantia nigra. However, injection of acylated ghrelin also elevated plasma des-acylated ghrelin, indicating in vivo deacetylation. Next, we chronically administered des-acylated ghrelin to Ghrelin KO mice and observed no neuroprotective effects in terms of TH cell number, TH protein expression, glial fibrillary acidic protein and ionized calcium binding adaptor molecule 1 cell number. The lack of a protective effect was mirrored in ghrelin-O-acyltransferase KO mice, which lack the ability to acylate ghrelin and consequently these mice have chronically increased plasma des-acyl ghrelin. Plasma corticosterone was elevated in ghrelin-O-acyltransferase KO mice and with des-acylated ghrelin administration. Overall, our studies suggest that acylated ghrelin is the isoform responsible for in vivo neuroprotection and that pharmacological approaches preventing plasma conversion from acyl ghrelin to des-acyl ghrelin may have clinical efficacy to help slow or prevent the debilitating effects of PD. Ghrelin exists in the plasma as acyl and des-acyl ghrelin. We determined the form responsible for in vivo neuroprotection in a mouse model of Parkinson's disease. Although exogenous acyl ghrelin

  1. CSM RCS Design Considerations and Failure Modes

    NASA Technical Reports Server (NTRS)

    Interbartolo, Michael

    2009-01-01

    Objectives include: a) Define major Command and Service Module (CSM) design considerations; b) List Command Module (CM) RCS failures and lessons learned; and c) List Service Module (SM) RCS failures and lessons learned.

  2. Program Helps In Analysis Of Failures

    NASA Technical Reports Server (NTRS)

    Stevenson, R. W.; Austin, M. E.; Miller, J. G.

    1993-01-01

    Failure Environment Analysis Tool (FEAT) computer program developed to enable people to see and better understand effects of failures in system. User selects failures from either engineering schematic diagrams or digraph-model graphics, and effects or potential causes of failures highlighted in color on same schematic-diagram or digraph representation. Uses digraph models to answer two questions: What will happen to system if set of failure events occurs? and What are possible causes of set of selected failures? Helps design reviewers understand exactly what redundancies built into system and where there is need to protect weak parts of system or remove them by redesign. Program also useful in operations, where it helps identify causes of failure after they occur. FEAT reduces costs of evaluation of designs, training, and learning how failures propagate through system. Written using Macintosh Programmers Workshop C v3.1. Can be linked with CLIPS 5.0 (MSC-21927, available from COSMIC).

  3. Heart failure - what to ask your doctor

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000224.htm Heart failure - what to ask your doctor To use the ... a pump that moves blood through your body. Heart failure occurs when blood does not move well and ...

  4. Limitations and Failures of the Layzer Model

    SciTech Connect

    Mikaelian, K O

    2007-12-21

    We report several limitations and failure modes of the recently expanded Layzer model for hydrodynamic instabilities. The failures occur for large initial amplitudes, for stable accelerations, and for spikes in two-fluid systems.

  5. Make Program Failures Work for You.

    ERIC Educational Resources Information Center

    Keller, M. Jean; Mills, Helen H.

    1984-01-01

    Recreation program planners can learn from program failures. Failures should not be viewed as negative statements about personnel. Examining feelings in a supportive staff environment is suggested as a technique for developing competence. (DF)

  6. 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.

  7. Contributions au probleme d'affectation des types d'avion

    NASA Astrophysics Data System (ADS)

    Belanger, Nicolas

    In this thesis, we approach the problem of assigning aircraft types to flights (what is called aircraft fleet assignment) in a strategic planning context. The literature mentions many studies considering this problem on a daily flight schedule basis, but the proposed models do no allow to consider many elements that are either necessary to assure the practical feasibility of the solutions, or relevant to get more beneficial solutions. After describing the practical context of the problem (Chapter 1) and presenting the literature on the subject (Chapter 2), we propose new models and solution approaches to improve the quality of' the solutions obtained. The general scheme of the thesis is presented in Chapter 3. We summarize here the models and solution approaches that we propose; and present the main elements of our conclusions. First, in Chapter 4, we consider the problem of aircraft fleet Assignment over a weekly flight schedule, integrating into the objective an homogeneity factor for driving the choice of the aircraft types for the flights with the same flight number over the week. We present an integer linear model based on a time-space multicommodity network. This model includes, among others, decision variables relative to the aircraft type assigned to each flight and to the dominant aircraft type assigned to each flight number. We present in Chapter 5 the results of a research project made in collaboration with Air Canada within a consulting contract. The project aimed at analyzing the relevance for the planners of using an optimization software to help them to first identify non profitable flight legs in the network, and second to efficiently establish the aircraft fleet assignment. In this chapter, we propose an iterative approach to take into account the fact that the passenger demand is not known on a leg basis, but rather on an origin-destination and departure time basis. Finally, in Chapter 6, we propose a model and a solution approach that aim at solving the fleet assignment problem over a periodic schedule in the case where there is a flexibility on the flight departure times and the fleet size must be minimized. Moreover, the objective of this model includes the impact on the passenger demand for each flight of the variation of the flight departure times and the closing of the departure times of consecutive flights connecting the same pairs of stations. (Abstract shortened by UMI.)

  8. 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.

  9. Khat Use: History and Heart Failure

    PubMed Central

    El-Menyar, Ayman; Mekkodathil, Ahammed; Al-Thani, Hassan; Al-Motarreb, Ahmed

    2015-01-01

    Recent reports suggest that 20 million people worldwide are regularly using khat as a stimulant, even though the habit of chewing khat is known to cause serious health issues. Historical evidence suggests khat use has existed since the 13th century in Ethiopia and the southwestern Arabian regions even before the cultivation and use of coffee. In the past three decades, its availability and use spread all over the world including the United States and Europe. Most of the consumers in the Western world are immigrant groups from Eastern Africa or the Middle East. The global transport and availability of khat has been enhanced by the development of synthetic forms of its active component. The World Health Organization considers khat a drug of abuse since it causes a range of health problems. However, it remains lawful in some countries. Khat use has long been a part of Yemeni culture and is used in virtually every social occasion. The main component of khat is cathinone, which is structurally and functionally similar to amphetamine and cocaine. Several studies have demonstrated that khat chewing has unfavorable cardiovascular effects. The effect on the myocardium could be explained by its effect on the heart rate, blood pressure, its vasomotor effect on the coronary vessels, and its amphetamine–like effects. However, its direct effect on the myocardium needs further elaboration. To date, there are few articles that contribute death among khat chewers to khat-induced heart failure. Further studies are needed to address the risk factors in khat chewers that may explain khat-induced cardiotoxicity, cardiomyopathy, and heart failure. PMID:25960830

  10. Sympathetically mediated hypertension in autonomic failure

    NASA Technical Reports Server (NTRS)

    Shannon, J. R.; Jordan, J.; Diedrich, A.; Pohar, B.; Black, B. K.; Robertson, D.; Biaggioni, I.; Roberton, D. (Principal Investigator)

    2000-01-01

    BACKGROUND: Approximately 50% of patients with primary autonomic failure have supine hypertension. We investigated whether this supine hypertension could be driven by residual sympathetic activity. METHODS AND RESULTS: In patients with multiple system atrophy (MSA) or pure autonomic failure (PAF), we studied the effect of oral yohimbine on seated systolic blood pressure (SBP), the effect of ganglionic blockade (with trimethaphan) on supine SBP and plasma catecholamine levels, and the effect of alpha(1)-adrenoreceptor blockade (phentolamine) on supine SBP. The SBP response to yohimbine was greater in patients with MSA than in those with PAF (area under the curve, 2248+/-543 versus 467+/-209 mm Hg. min; P=0.022). MSA patients with a higher supine SBP had a greater response than those with a lower supine SBP (3874+/-809 versus 785+/-189 mm Hg. min; P=0. 0017); this relationship was not seen in PAF patients. MSA patients had a marked depressor response to low infusion rates of trimethaphan; the response in PAF patients was more variable. Plasma norepinephrine decreased in both groups, but heart rate did not change in either group. At 1 mg/min, trimethaphan decreased supine SBP by 67+/-8 and 12+/-6 mm Hg in MSA and PAF patients, respectively (P<0.0001). Cardiac index and total peripheral resistance decreased in MSA patients by 33.4+/-5.8% and 40.7+/-9.5%, respectively (P=0. 0015). Patients having a depressor response to trimethaphan also had a depressor response to phentolamine. In MSA patients, the pressor response to yohimbine and the decrease in SBP with 1 mg/min trimethaphan were correlated (r=0.98; P=0.001). CONCLUSIONS: Residual sympathetic activity drives supine hypertension in MSA. It contributes to, but does not completely explain, supine hypertension in PAF.

  11. Gene therapy for heart failure.

    PubMed

    Greenberg, Barry

    2015-09-01

    Heart failure is a major public health problem throughout the world and it is likely that its prevalence will continue to grow over the next several decades. Despite advances in the treatment of heart failure, morbidity and mortality remain unacceptably high. Gene transfer therapy provides a novel strategy for targeting abnormalities in cardiac cells that adversely affect cardiac function. New vectors for gene delivery, mainly adeno-associated viruses (AAVs) that are preferentially taken up by cardiomyocytes, can result in sustained transgene expression. The cardiac isoform of sarco(endo)plasmic reticulum Ca(2+)ATPase (SERCA2a) plays a major role in regulating calcium levels in cardiomyocytes. Abnormal calcium handling by the failing heart caused by a reduction in SERCA2a activity adversely affects both systolic and diastolic function. The Calcium Upregulation by Percutaneous Administration of Gene Therapy in Cardiac Disease (CUPID) study was a Phase 2a double-blind, randomized, placebo-controlled, dose-finding study that was performed in patients with advanced heart failure due to systolic dysfunction. Eligible patients received AAV/SERCA2a or placebo by direct antegrade infusion into the coronary circulation. At the end of 12 months, patients receiving high-dose therapy (i.e. 1×10(13) DNase Resistant Particles) had evidence of favorable changes in several clinically relevant domains compared to patients treated with placebo. There were no safety concerns at any dose of AAV/SERCA2a. Patients treated with AAV/SERCA2a exhibited a striking reduction in cardiovascular events that persisted through 36 months of follow-up compared to patients who received placebo. Transgene expression was detected in the myocardium of patients receiving AAV/SERCA2a gene therapy as long as 31 months after delivery. A second Phase 2b study, CUPID 2, designed to confirm this favorable effect on heart failure events, is currently underway with the results expected to be presented later in

  12. 26 CFR 301.6501(n)-2 - Certain contributions to section 501(c)(3) organizations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... private foundation makes a contribution to a section 501(c)(3) organization as provided in section 4942(g)(3), and a deficiency of tax of such foundation occurs due to the failure of the section...

  13. Failure analysis: Status and future trends

    SciTech Connect

    Anderson, R.E.; Soden, J.M.; Henderson, C.L.

    1995-02-01

    Failure analysis is a critical element in the integrated circuit manufacturing industry. This paper reviews the changing role of failure analysis and describes major techniques employed in the industry today. Several advanced failure analysis techniques that meet the challenges imposed by advancements in integrated circuit technology are described and their applications are discussed. Future trends in failure analysis needed to keep pace with the continuing advancements in integrated circuit technology are anticipated.

  14. The role of exogenous risk factors of antituberculosis treatment failure

    PubMed Central

    LESNIC, EVELINA; USTIAN, AURELIA; POP, CARMEN MONICA

    2016-01-01

    Background and aim The Republic of Moldova reports the highest incidence of tuberculosis and the lowest treatment success rate among European region countries. In most of the patients the antituberculosis treatment failure is correlated with social risk factors (low socio-economical state, epidemiological danger characteristics) and biological factors (young age, male sex, physiological conditions, associated diseases). Clinical factors (advanced forms of tuberculosis, chronic evolution, immune disturbances), therapeutic factors (treatment errors and interruptions, individualized regimens) and administrative factors (drug interruption in supply, suboptimal treatment quality) prevail in regions with defficient in health care delivery. The association of risk factors has a higher impact than the severity of one risk factor. The risk factor assessment is very important before initiation of the treatment, for establishing the plan of risk reduction measures for increasing the success rate. The aim of the study was to determine the impact of exogenous risk factors on antituberculosis treatment failure. Methods The study was conducted on 201 patients with pulmonary tuberculosis and treatment failure and 105 patients with pulmonary tuberculosis who successfully finished the antituberculosis treatment. Selected cases were investigated according national standards. Results The treatment failure occurred in patients belonging to socially disadvantaged groups, patients with harmful habits (alcohol abuse, drug use, active smoking), patients from infectious clusters. Migration, homelessness and detention releasing imperil the quality of treatment, thus predisposing to the treatment failure. Social, educational support and the substitutive therapy and withdrawal techniques (tobacco, alcohol, psycho-active substances) must be implemented in the high risk groups in order to diminish the risk of treatment failure and to increase the treatment success rate. Conclusions The study of

  15. Thermographic Observation Of Pyrotechnic Fuse Failure

    NASA Astrophysics Data System (ADS)

    Abney, Linda D.; Mohler, Jonathan H.

    1987-05-01

    Certain metal combinations alloy, with release of large amounts of energy. Palladium/Aluminum is available commercially in the form of wire, braid and foil of various diameters and thicknesses. These products are useful as heat sources and as fuses to ignite other pyrotechnic compositions. We have found that when used in small devices, where the fuse wire may be required to go through narrow channels and sharp bends, the alloying reaction may not propagate reliably. We have used infrared thermography to monitor heat flow in the fuse wire and in materials surrounding it, to observe the thermal dynamics involved in fuse wire propagation. Fuse wire can be ignited by passing an electrical current through it from end to end or it can be lit from one end to carry ignition to other locations in a device or system. Two effects have been observed thermographically: Conductive cooling of the wire where effective thermal contact occurs and hot zone formation at stress points produced by sharp bends. Thermographic measurements have demonstrated that when electrical current is used to ignite palladium/aluminum wire or braid, reaction begins farthest from a heat sink region, or at a sharp bend.The problem with high thermal contact is easily understood since heat sinking can cool the fuse wire and retard reaction, even to the point of failure. Hot zone formation at high stress regions may, on the other hand, not appear detrimental. However, if one recognizes that these hot zones result from high electrical resistance, probably due to microscopic cracks formed in the palladium sheath of the fuse wire, it is easy to see that a corresponding thermal resistance will also be present. Such a high thermal resistance point, when coupled with adjacent conductive cooling paths can contribute to fuse failure.By using infrared scanning, one can not only observe the importance of such effects in fuse wire ignition and propagation but also see where they may be occurring in a particular

  16. 30 CFR 57.7010 - Power failures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Power failures. 57.7010 Section 57.7010 Mineral... Drilling-Surface Only § 57.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  17. 30 CFR 56.7010 - Power failures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Power failures. 56.7010 Section 56.7010 Mineral... Drilling § 56.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  18. The advent of failure analysis software technology

    SciTech Connect

    Henderson, C.L.; Barnard, R.D.

    1994-02-01

    The increasing complexity of integrated circuits demands that software tools, in addition to hardware tools, be used for successful diagnosis of failure. A series of customizable software tools have been developed that organize failure analysis information and provide expert level help to failure analysts to increase their productivity and success.

  19. 30 CFR 56.7010 - Power failures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Power failures. 56.7010 Section 56.7010 Mineral... Drilling § 56.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  20. 30 CFR 57.7010 - Power failures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Power failures. 57.7010 Section 57.7010 Mineral... Drilling-Surface Only § 57.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  1. 30 CFR 57.7010 - Power failures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Power failures. 57.7010 Section 57.7010 Mineral... Drilling-Surface Only § 57.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  2. 30 CFR 57.7010 - Power failures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Power failures. 57.7010 Section 57.7010 Mineral... Drilling-Surface Only § 57.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  3. 30 CFR 57.7010 - Power failures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Power failures. 57.7010 Section 57.7010 Mineral... Drilling-Surface Only § 57.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  4. 30 CFR 56.7010 - Power failures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Power failures. 56.7010 Section 56.7010 Mineral... Drilling § 56.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  5. 30 CFR 56.7010 - Power failures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Power failures. 56.7010 Section 56.7010 Mineral... Drilling § 56.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  6. 30 CFR 56.7010 - Power failures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Power failures. 56.7010 Section 56.7010 Mineral... Drilling § 56.7010 Power failures. In the event of power failure, drill controls shall be placed in the neutral position until power is restored....

  7. Acute Renal Failure after Uterine Artery Embolization

    SciTech Connect

    Rastogi, Sachin; Wu, Yu-Hsin; Shlansky-Goldberg, Richard D.; Stavropoulos, S. William

    2004-09-15

    Renal failure is a potential complication of any endovascular procedure using iodinated contrast, including uterine artery embolization (UAE). In this report we present a case of acute renal failure (ARF) following UAE performed as a treatment for uterine fibroids. The likely causes of ARF in this patient are explored and the possible etiologies of renal failure in patients undergoing UAE are reviewed.

  8. Structural failures: Causes, prevention, and misinterpretation

    SciTech Connect

    Barsom, J.M. )

    1993-07-01

    This article presents a few observations on causes and prevention of failures in structural and equipment components that are related to the initiation and propagation of fatigue cracks. Some of these observations are illustrated by using actual failures. Also, the article presents a discussion of some common misconceptions and misinterpretations that have led to incorrect conclusions in failure investigations.

  9. Learning from Failures: Archiving and Designing with Failure and Risk

    NASA Technical Reports Server (NTRS)

    VanWie, Michael; Bohm, Matt; Barrientos, Francesca; Turner, Irem; Stone, Robert

    2005-01-01

    Identifying and mitigating risks during conceptual design remains an ongoing challenge. This work presents the results of collaborative efforts between The University of Missouri-Rolla and NASA Ames Research Center to examine how an early stage mission design team at NASA addresses risk, and, how a computational support tool can assist these designers in their tasks. Results of our observations are given in addition to a brief example of our implementation of a repository based computational tool that allows users to browse and search through archived failure and risk data as related to either physical artifacts or functionality.

  10. Are Your Students Ready for Anatomy and Physiology? Developing Tools to Identify Students at Risk for Failure

    ERIC Educational Resources Information Center

    Gultice, Amy; Witham, Ann; Kallmeyer, Robert

    2015-01-01

    High failure rates in introductory college science courses, including anatomy and physiology, are common at institutions across the country, and determining the specific factors that contribute to this problem is challenging. To identify students at risk for failure in introductory physiology courses at our open-enrollment institution, an online…

  11. 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

  12. An analysis of the causes of failure in high chrome oxide refractory materials from slagging gasifiers

    SciTech Connect

    Bennett, James P.; Kwong, Kyei-Sing; Powell, Cynthia A.; Thomas, Hugh; Krabbe, Rick

    2006-01-01

    High Cr2O3 refractory materials are used to line the hot face of slagging gasifiers. Gasifiers are reaction chambers that convert water, oxygen, and a carbon feedstock into CO, H2, and methane at temperatures as high as 1575DGC and pressures up to 1000 psi. Ash in the carbon feedstock liquefies, erodes and corrodes the gasifier's refractory liner, contributing to liner failure within a few months to two years. The failure of a refractory liner decreases a gasifier's on-line availability and causes costly system downtime and repairs. Many factors contribute to refractory lining failure, including slag penetration and corrosion, thermal cycling, gasifier environment, and mechanical loads. The results of refractory post-mortem failure analysis and how observations relate to gasifier service life will be discussed.

  13. Analysis of the causes of failure in high chrome oxide refractory materials from slagging gasifiers

    SciTech Connect

    Bennett, J.P.; Kwong, K.-S.; Powell, C.A.; Thomas, H.; Krabbe, R.A.

    2006-03-01

    High Cr2O3 refractory materials are used to line the hot face of slagging gasifiers. Gasifiers are reaction chambers that convert water, oxygen, and a carbon feedstock into CO, H2, and methane at temperatures as high as 1575oC and pressures up to 1000 psi. Ash in the carbon feedstock liquefies, erodes and corrodes the gasifier’s refractory liner, contributing to liner failure within a few months to two years. The failure of a refractory liner decreases a gasifier’s on-line availability and causes costly system downtime and repairs. Many factors contribute to refractory lining failure, including slag penetration and corrosion, thermal cycling, gasifier environment, and mechanical loads. The results of refractory post-mortem failure analysis and how observations relate to gasifier service life will be discussed.

  14. Les neuropeptides gastro-intestinaux cibles des effets des rayonnements ionisants : altérations fonctionnelles

    NASA Astrophysics Data System (ADS)

    Linard, C.; Esposito, V.; Wysocki, J.; Griffiths, N. M.

    1998-04-01

    The symptoms associated with exposure to ionizing radiation are nausea, vomiting, diarrhoea. The response of the gut is complex involving modifications of motility and fluid and electrolyte transport. Gastrointestinal regulatory peptides have an important role in these functions. This study showed that radiation-induced tissue variations of neuropeptides have some repercussions on intestinal biological activity of these peptides soon after irradiation. In addition such modifications are also seen a few years after irradiation. Les symptômes associés à l'exposition aux rayonnements ionisants sont des nausées, vomissements et diarrhées. La réponse du système digestif est complexe, impliquant des modifications de la motilité et du transport d'eau et d'électrolytes. les neuropeptides gastro-intestinaux ont un rôle important dans ces fonctions. Cette étude montre que les variations tissulaires de ces neuropeptides induites par l'irradiation ont des répercussions sur l'activité biologique intestinale pour des temps précoces mais que ces perturbations sont encore visibles quelques années après l'irradiation.

  15. Comparaison des effets des irradiations γ, X et UV dans les fibres optiques

    NASA Astrophysics Data System (ADS)

    Girard, S.; Ouerdane, Y.; Baggio, J.; Boukenter, A.; Meunier, J.-P.; Leray, J.-L.

    2005-06-01

    Les fibres optiques présentent de nombreux avantages incitant à les intégrer dans des applications devant résister aux environnements radiatifs associés aux domaines civil, spatial ou militaire. Cependant, leur exposition à un rayonnement entraîne la création de défauts ponctuels dans la silice amorphe pure ou dopée qui constitue les différentes parties de la fibre optique. Ces défauts causent, en particulier, une augmentation transitoire de l'atténuation linéique des fibres optiques responsable de la dégradation voire de la perte du signal propagé dans celles-ci. Dans cet article, nous comparons les effets de deux types d'irradiation: une impulsion X et une dose γ cumulée. Les effets de ces irradiations sont ensuite comparés avec ceux induits par une insolation ultraviolette (244 nm) sur les propriétés d'absorption des fibres optiques. Nous montrons qu'il existe des similitudes entre ces différentes excitations et qu'il est possible, sous certaines conditions, d'utiliser celles-ci afin d'évaluer la capacité de certaines fibres optiques à fonctionner dans un environnement nucléaire donné.

  16. 1. ORIGINAL STONE ARCH BRIDGE OVER THE DES PLAINES RIVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. ORIGINAL STONE ARCH BRIDGE OVER THE DES PLAINES RIVER AT NINTH STREET IN LOCKPORT. THE BRIDGE WAS BUILT ABOUT 1865. NOTE METAL CLAMP ON THE NEAR PIER AND THE 20TH CENTURY REINFORCED CONCRETE ADDITION. - Lockport Historic District, Stone Arch Bridge, Spanning Des Plaines River at Ninth Street, Lockport, Will County, IL

  17. 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.

  18. 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. PMID:25811935

  19. 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.

  20. Determining the Cause of a Header Failure in a Natural Gas Production Facility

    SciTech Connect

    Matthes, S.A.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.; Holcomb, G.R.

    2007-03-01

    An investigation was made into the premature failure of a gas-header at the Rocky Mountain Oilfield Testing Center (RMOTC) natural gas production facility. A wide variety of possible failure mechanisms were considered: design of the header, deviation from normal pipe alloy composition, physical orientation of the header, gas composition and flow rate, type of corrosion, protectiveness of the interior oxide film, time of wetness, and erosion-corrosion. The failed header was examined using metallographic techniques, scanning electron microscopy, and microanalysis. A comparison of the failure site and an analogous site that had not failed, but exhibited similar metal thinning was also performed. From these studies it was concluded that failure resulted from erosion-corrosion, and that design elements of the header and orientation with respect to gas flow contributed to the mass loss at the failure point.

  1. Obesity and heart failure as a mediator of the cerebrorenal interaction.

    PubMed

    Jindal, Ankur; Whaley-Connell, Adam; Sowers, James R

    2013-01-01

    The obesity epidemic is contributing substantially to the burden of cardiovascular disease including heart disease and congestive heart failure, in the United States and the rest of the world. Overnutrition as a driver of obesity, promotes alterations in fatty acid, lipid, and glucose metabolism that influence myocardial function and progression of heart failure from diastolic to systolic failure. The association of progressive heart failure and progressive chronic kidney disease is well documented and often referred to as the cardiorenal syndrome, as well as a prognosticator for cerebrovascular disease (e.g. stroke). Whether the relationship between obesity, heart disease/failure and risk for chronic kidney disease and stroke is direct or a confluence of risk factors is poorly understood.

  2. 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

  3. 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

  4. Real-time failure control (SAFD)

    NASA Technical Reports Server (NTRS)

    Panossian, Hagop V.; Kemp, Victoria R.; Eckerling, Sherry J.

    1990-01-01

    The Real Time Failure Control program involves development of a failure detection algorithm, referred as System for Failure and Anomaly Detection (SAFD), for the Space Shuttle Main Engine (SSME). This failure detection approach is signal-based and it entails monitoring SSME measurement signals based on predetermined and computed mean values and standard deviations. Twenty four engine measurements are included in the algorithm and provisions are made to add more parameters if needed. Six major sections of research are presented: (1) SAFD algorithm development; (2) SAFD simulations; (3) Digital Transient Model failure simulation; (4) closed-loop simulation; (5) SAFD current limitations; and (6) enhancements planned for.

  5. Malignant vagotonia due to selective baroreflex failure

    NASA Technical Reports Server (NTRS)

    Jordan, J.; Shannon, J. R.; Black, B. K.; Costa, F.; Ertl, A. C.; Furlan, R.; Biaggioni, I.; Robertson, D.

    1997-01-01

    Baroreflex failure is characterized by dramatic fluctuations of sympathetic activity and paroxysms of hypertension and tachycardia. In contrast, unopposed parasympathetic activity has not been described in patients with baroreflex failure because of concurrent parasympathetic denervation of the heart. We describe the unusual case of a patient with baroreflex failure in a setting of preserved parasympathetic control of HR manifesting episodes of severe bradycardia and asystole. Thus, parasympathetic control of the HR may be intact in occasional patients with baroreflex failure. Patients with this selective baroreflex failure require a unique therapeutic strategy for the control of disease manifestations.

  6. 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.

  7. 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.

  8. Impairment of cardiac function and energetics in experimental renal failure.

    PubMed Central

    Raine, A E; Seymour, A M; Roberts, A F; Radda, G K; Ledingham, J G

    1993-01-01

    Cardiac function and energetics in experimental renal failure in the rat (5/6 nephrectomy) have been investigated by means of an isolated perfused working heart preparation and an isometric Langendorff preparation using 31P nuclear magnetic resonance (31P NMR). 4 wk after nephrectomy cardiac output of isolated hearts perfused with Krebs-Henseleit buffer was significantly lower (P < 0.0001) at all levels of preload and afterload in the renal failure groups than in the pair-fed sham operated control group. In control hearts, cardiac output increased with increases in perfusate calcium from 0.73 to 5.61 mmol/liter whereas uremic hearts failed in high calcium perfusate. Collection of 31P NMR spectra from hearts of renal failure and control animals during 30 min normoxic Langendorff perfusion showed that basal phosphocreatine was reduced by 32% to 4.7 mumol/g wet wt (P < 0.01) and the phosphocreatine to ATP ratio was reduced by 32% (P < 0.01) in uremic hearts. During low flow ischemia, there was a substantial decrease in phosphocreatine in the uremic hearts and an accompanying marked increase in release of inosine into the coronary effluent (14.9 vs 6.1 microM, P < 0.01). We conclude that cardiac function is impaired in experimental renal failure, in association with abnormal cardiac energetics and increased susceptibility to ischemic damage. Disordered myocardial calcium utilization may contribute to these derangements. PMID:8254048

  9. Common Cause Failure Modeling in Space Launch Vehicles

    NASA Technical Reports Server (NTRS)

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

    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 for example by system environments, manufacturing, transportation, storage, maintenance, and assembly. Since there are many factors that contribute to CCFs, they can be reduced, but are difficult to eliminate entirely. Furthermore, failure databases sometimes fail to differentiate between independent and dependent CCF. Because common cause failure data is limited in the aerospace industry, the Probabilistic Risk Assessment (PRA) Team at Bastion Technology Inc. is estimating CCF risk using generic data collected by the Nuclear Regulatory Commission (NRC). Consequently, common cause risk estimates based on this database, when applied to other industry applications, are highly uncertain. Therefore, it is important to account for a range of values for independent and CCF risk and to communicate the uncertainty to decision makers. There is an existing methodology for reducing CCF risk during design, which includes a checklist of 40+ factors grouped into eight categories. Using this checklist, an approach to produce a beta factor estimate is being investigated that quantitatively relates these factors. In this example, the checklist will be tailored to space launch vehicles, a quantitative approach will be described, and an example of the method will be presented.

  10. Advances in the management of acute liver failure

    PubMed Central

    Wang, Da-Wei; Yin, Yi-Mei; Yao, Yong-Ming

    2013-01-01

    Acute liver failure (ALF) is an uncommon but dramatic clinical syndrome characterized by hepatic encephalopathy and a bleeding tendency due to abrupt loss of liver function caused by massive or submassive liver necrosis in a patient with a previously healthy liver. The causes of ALF encompass a wide variety of toxic, viral, metabolic, vascular and autoimmune insults to the liver, and identifying the correct cause can be difficult or even impossible. Many patients with ALF develop a cascade of serious complications involving almost every organ system, and death is mostly due to multi-organ failure, hemorrhage, infection, and intracranial hypertension. Fortunately, the outcome of ALF has been improved in the last 3 decades through the specific treatment for the disease of certain etiology, and the advanced intensive care management. For most severely affected patients who fail to recover after treatment, rapid evaluation for transfer to a transplantation center and consideration for liver transplantation is mandatory so that transplantation can be applied before contraindications develop. This review focuses on the recent advances in the understanding of various contributing etiologies, the administration of etiology-specific treatment to alleviate the liver injury, and the management of complications (e.g., encephalopathy, coagulopathy, cardiovascular instability, respiratory failure, renal failure, sepsis and metabolic disturbance) in patients with ALF. Assessment of the need for liver transplantation is also presented. PMID:24222950

  11. Prognosis of morbid obesity patients with advanced heart failure.

    PubMed

    Nagarajan, Vijaiganesh; Cauthen, Clay A; Starling, Randall C; Tang, Wai Hong Wilson

    2013-01-01

    Obese patients have been noted to have better prognosis in many conditions including heart failure. We hypothesize that this favorable prognosis for obesity may not be seen in patients with morbid obesity and advanced heart failure. A total of 501 consecutive patients with advanced heart failure referred for heart transplant evaluation to the Cleveland Clinic were studied. Patients were categorized into 3 groups based on their body mass index score as nonobese (≤30 kg/m(2) ), obese (30.1-40 kg/m(2) ), and morbidly obese (≥40 kg/m(2) ). There were fewer cardiovascular risk factors in the morbidly obese group. Unadjusted event-free survival rates were 48.4%, 57.4%, and 28.6% in the nonobese, obese, and morbidly obese groups, respectively (P=.02). In univariate analysis, both the nonobese group (hazard ratio [HR], 1.44; 95% confidence interval [CI], 1.09-1.91; P=.01) and the morbidly obese group (HR, 2.46; 95% CI, 1.40-4.30; P=.002) had significantly higher risk of all-cause mortality/transplantation compared with the obese group. This difference persisted in multivariate analysis after adjustment for confounding factors. Our study re-emphasizes the presence of an obesity paradox even in patients with very advanced heart failure. This favorable prognosis, however, may not be relevant in patients with morbidly obesity. Cardiovascular risk factors may not contribute to this phenomenon.

  12. Tolvaptan: A Novel Diuretic in Heart Failure Management.

    PubMed

    Zulkifli Amin, Hilman; Suridanda Danny, Siska

    2016-01-13

    Heart failure (HF) is still a major problem worldwide with high morbidity and mortality rates. The recently developed medication for HF is still incapable of reducing its morbidity and mortality, and clinical data supporting the efficacy and safety of its mainstay therapy remain insufficient. Arginine-vasopressin (AVP) plays important roles in circulatory and water homeostasis, one of which is water retention through the V2 receptor. In patients with HF, there is an increased level of AVP, contributing to such symptoms as edema, dyspnea, and congestion. Tolvaptan as a selective V2 receptor antagonist, in addition to the conventional therapy, has been shown to cause an increase in net fluid loss, a decrease in body weight, and a reduction in the rate of HF exacerbation. Such evidence has been provided by the Acute and Chronic Therapeutic Impact of a Vasopressin Antagonist (ACTIV) in Congestive Heart Failure (CHF), Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study With Tolvaptan (EVEREST), Acute Heart Failure Volume Control Multicenter Randomized (AVCMA), and Study of Ascending Levels of Tolvaptan in hyponatremia 1and 2 (SALT-1 and SALT-2) trials. Tolvaptan can be an alternative diuretic in conjunction with other standard therapies for HF and has already been proved to be able to decrease morbidity and mortality, especially in HF patients with hyponatremia. PMID:27403182

  13. Non-organic failure to thrive: a reappraisal.

    PubMed

    Skuse, D H

    1985-02-01

    Non-organic failure to thrive has traditionally been regarded as due primarily to maternal rejection and neglect. A critical reappraisal of the evidence suggests a more balanced view of the mother-child relationship should be taken. A classification of the condition, founded on facts not concepts, is urgently required. Non-organic failure to thrive should be viewed in a multidimensional context, in which potential influences upon the symptomatic infant are considered. Inadequacy of nutrition is caused by both a failure of adequate provision of food and by inadequate intake. A vicious circle of maladaptive behavioural interaction between caregiver and infant is often present, sustained by high emotional tensions. Clinical intervention should aim to clarify the contributions made by both caregiver and infant to that interaction and thus break the cycle. The basis on which intervention is made should be direct observation of the parent and child relationship in as many different environmental contexts as feasible, especially during feeding. The multidisciplinary team has an important role to play in management. An emphasis on parental culpability in the aetiology of non-organic failure to thrive, in the absence of direct evidence of neglect, is wrong. PMID:3883912

  14. Buckling failures in insect exoskeletons.

    PubMed

    Parle, Eoin; Herbaj, Simona; Sheils, Fiona; Larmon, Hannah; Taylor, David

    2016-02-01

    Thin walled tubes are often used for load-bearing structures, in nature and in engineering, because they offer good resistance to bending and torsion at relatively low weight. However, when loaded in bending they are prone to failure by buckling. It is difficult to predict the loading conditions which cause buckling, especially for tubes whose cross sections are not simple shapes. Insights into buckling prevention might be gained by studying this phenomenon in the exoskeletons of insects and other arthropods. We investigated the leg segments (tibiae) of five different insects: the locust (Schistocerca gergaria), American cockroach (Periplaneta americana), death's head cockroach (Blaberus discoidalis), stick insect (Parapachymorpha zomproi) and bumblebee (Bombus terrestris audax). These were tested to failure in cantilever bending and modelled using finite element analysis (FEA). The tibiae of the locust and the cockroaches were found to be approximately circular in shape. Their buckling loads were well predicted by linear elastic FEA, and also by one of the analytical solutions available in the literature for elastic buckling. The legs of the stick insect are also circular in cross section but have several prominent longitudinal ridges. We hypothesised that these ridges might protect the legs against buckling but we found that this was not the case: the loads necessary for elastic buckling were not reached in practice because yield occurred in the material, causing plastic buckling. The legs of bees have a non-circular cross section due to a pollen-carrying feature (the corbicula). We found that this did not significantly affect their resistance to buckling. Our results imply that buckling is the dominant failure mode in the tibia of insects; it likely to be a significant consideration for other arthropods and any organisms with stiff exoskeletons. The interactions displayed here between material properties and cross sectional geometry may provide insights for the

  15. Heart Failure in Rural Communities.

    PubMed

    Verdejo, Hugo E; Ferreccio, Catterina; Castro, Pablo F

    2015-10-01

    Patients with chronic heart failure (CHF) living in rural areas face an increased risk of adverse cardiovascular events. Even in countries with universal access to health care, rural areas are characteristically underserved, with reduced health care providers supply, greater distance to health care centers, decreased physician density with higher reliance on generalists, and high health care staff turnover. On the other hand, patient-related characteristics vary widely among published data. This review describes the epidemiology of CHF in rural or remote settings, organizational and patient-related factors involved in cardiovascular outcomes, and the role of interventions to improve rural health care.

  16. Nutritional support during liver failure.

    PubMed

    Gecelter, G R; Comer, G M

    1995-07-01

    Critically ill patients in varying degrees of liver failure are catabolic and consequently require expeditious caloric support. Unique problems in this group of patients essentially revolve around the diagnosis and management of hepatic encephalopathy. From the overview provided in this text, it can be concluded that, only in overt hepatic coma, should all nitrogen products be withheld while precipitating causes are evaluated. Protein should be reintroduced as rapidly as possible to avoid the consequences of protein deprivation. Once the acute intercurrent illness has resolved, the cirrhotic patient returns to baseline energy and protein requirements indistinguishable from the population at large. PMID:7552976

  17. [Diuretic therapy in heart failure].

    PubMed

    Trullàs, Joan Carles; Morales-Rull, José Luís; Formiga, Francesc

    2014-02-20

    Many of the primary clinical manifestations of heart failure (HF) are due to fluid retention, and treatments targeting congestion play a central role in HF management. Diuretic therapy remains the cornerstone of congestion treatment, and diuretics are prescribed to the majority of HF patients. Despite this ubiquitous use, there is limited evidence from prospective randomized studies to guide the use of diuretics. With the chronic use of diuretic and usually in advanced stages of HF, diuretics may fail to control salt and water retention. This review describes the mechanism of action of available diuretic classes, reviews their clinical use based on scientific evidence and discusses strategies to overcome diuretic resistance.

  18. Failure Assessment of Brazed Structures

    NASA Technical Reports Server (NTRS)

    Flom, Yuri

    2012-01-01

    Despite the great advances in analytical methods available to structural engineers, designers of brazed structures have great difficulties in addressing fundamental questions related to the loadcarrying capabilities of brazed assemblies. In this chapter we will review why such common engineering tools as Finite Element Analysis (FEA) as well as many well-established theories (Tresca, von Mises, Highest Principal Stress, etc) don't work well for the brazed joints. This chapter will show how the classic approach of using interaction equations and the less known Coulomb-Mohr failure criterion can be employed to estimate Margins of Safety (MS) in brazed joints.

  19. Mineralcorticoid antagonists in heart failure.

    PubMed

    D'Elia, Emilia; Krum, Henry

    2014-10-01

    Mineralocorticoid receptor antagonists (MRAs) have become mandated therapy in patients with reduced ejection fraction (systolic) heart failure (HF) across all symptom classes. These agents should also be prescribed in the early post-myocardial infarction setting in those with reduced ejection fraction and either HF symptoms or diabetes. This article explores the pathophysiological role of aldosterone, an endogenous ligand for the mineralcorticoid receptor (MR), and summarizes the clinical data supporting guideline recommendations for these agents in systolic HF. The use of MRAs in novel areas beyond systolic HF ejection is also explored. Finally, the current status of newer agents will be examined. PMID:25217431

  20. Socioeconomic Inequalities in Heart Failure.

    PubMed

    Díaz-Toro, Felipe; Verdejo, Hugo E; Castro, Pablo F

    2015-10-01

    Prevalence and incidence of chronic heart failure (CHF) has increased during the past decades. Beyond its impact on mortality rates, CHF severely impairs quality of life, particularly with the elderly and vulnerable population. Several studies have shown that CHF takes its toll mostly on the uneducated, low-income population, who exhibit impaired access to health care systems, less knowledge regarding its pathology and poorer self-care behaviors. This review summarizes the available evidence linking socioeconomic inequalities and CHF, focusing on the modifiable factors that may explain the impaired health outcomes in socioeconomically deprived populations. PMID:26462090

  1. Post-hepatectomy liver failure

    PubMed Central

    Kauffmann, Rondi

    2014-01-01

    Hepatectomies are among some of the most complex operative interventions performed. Mortality rates after major hepatectomy are as high as 30%, with post-hepatic liver failure (PHLF) representing the major source of morbidity and mortality. We present a review of PHLF, including the current definition, predictive factors, pre-operative risk assessment, techniques to prevent PHLF, identification and management. Despite great improvements in morbidity and mortality, liver surgery continues to demand excellent clinical judgement in selecting patients for surgery. Appropriate choice of pre-operative techniques to improve the functional liver remnant (FLR), fastidious surgical technique, and excellent post-operative management are essential to optimize patient outcomes. PMID:25392835

  2. [Bone-based anchorage failure].

    PubMed

    Mer, Grégoria; Brezulier, Damien; Sorel, Olivier

    2016-03-01

    The aim of this article is to list the circumstances likely to give rise to failure of orthodontic temporary bone-supported anchorage and, hence, to attempt to define criteria for correct miniscrew usage. Our study was based on a review of the literature and analyses of clinical cases. Our findings show that, with a sound knowledge of the indications for screw selection and positioning and of the insertion protocols combined with a clear understanding of orthodontic mechanics, bone-based anchorage can henceforth provide orthodontists with an essential tool to enable formerly unachievable dental movements and to stabilize unwanted movements, thus making treatment both more reliable and more effective. PMID:27083224

  3. Organic Evaporator steam valve failure

    SciTech Connect

    Jacobs, R. A.

    1992-09-29

    DWPF Technical has requested an analysis of the capacity of the organic Evaporator (OE) condenser (OEC) be performed to determine its capability in the case where the OE steam flow control valve fails open. Calculations of the OE boilup and the OEC heat transfer coefficient indicate the OEC will have more than enough capacity to remove the heat at maximum OE boilup. In fact, the Salt Cell Vent Condenser (SCVC) should also have sufficient capacity to handle the maximum OE boilup. Therefore it would require simultaneous loss of OEC and/or SCVC condensing capacity for the steam valve failure to cause high benzene in the Process Vessel Vent System (PVVS).

  4. Fracture - An Unforgiving Failure Mode

    NASA Technical Reports Server (NTRS)

    Goodin, James Ronald

    2006-01-01

    During the 2005 Conference for the Advancement for Space Safety, after a typical presentation of safety tools, a Russian in the audience simply asked, "How does that affect the hardware?" Having participated in several International System Safety Conferences, I recalled that most attention is dedicated to safety tools and little, if any, to hardware. The intent of this paper on the hazard of fracture and failure modes associated with fracture is my attempt to draw attention to the grass roots of system safety - improving hardware robustness and resilience.

  5. Predicting Failure Progression and Failure Loads in Composite Open-Hole Tension Coupons

    NASA Technical Reports Server (NTRS)

    Arunkumar, Satyanarayana; Przekop, Adam

    2010-01-01

    Failure types and failure loads in carbon-epoxy [45n/90n/-45n/0n]ms laminate coupons with central circular holes subjected to tensile load are simulated using progressive failure analysis (PFA) methodology. The progressive failure methodology is implemented using VUMAT subroutine within the ABAQUS(TradeMark)/Explicit nonlinear finite element code. The degradation model adopted in the present PFA methodology uses an instantaneous complete stress reduction (COSTR) approach to simulate damage at a material point when failure occurs. In-plane modeling parameters such as element size and shape are held constant in the finite element models, irrespective of laminate thickness and hole size, to predict failure loads and failure progression. Comparison to published test data indicates that this methodology accurately simulates brittle, pull-out and delamination failure types. The sensitivity of the failure progression and the failure load to analytical loading rates and solvers precision is demonstrated.

  6. Aluminium intoxication in undialysed adults with chronic renal failure.

    PubMed Central

    Russo, L S; Beale, G; Sandroni, S; Ballinger, W E

    1992-01-01

    The dialysis encephalopathy syndrome (DES) consists of altered mental status, communication difficulty, seizures and myoclonus. It has been attributed to elevated serum aluminium (A1) levels. Two undialysed patients with chronic renal failure who presented with the characteristic syndrome are reported. The first, a 48 year old female, had used A1 containing phosphate binders for two years. Her serum A1 level was 25.34 mumol/L. Despite treatment with desferoximine and dialysis, she died. Necropsy revealed elevated A1 levels in the cerebral cortex (19 mcg/gm) and spongioform change in the outer three cortical layers. The second patient, a 46 year old woman, had a serum A1 of 8.70 mumol/L. She had never taken A1 containing phosphate binders but had taken several grams/day of citrate for at least six months. Treatment with haemodialysis and discontinuation of the citrate produced a resolution of symptoms and return of the A1 level to normal. During two years of haemodialysis there has been no recurrence. Images PMID:1527541

  7. 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.

  8. Renal failure in patients with multiple myeloma.

    PubMed

    Almueilo, Samir H

    2015-01-01

    Renal dysfunction is encountered in 20-25% of patients with multiple myeloma (MM) at the time of diagnosis. There is often a precipitating event. Several biochemical and clinical correlations with renal failure in MM have been reported. Renal failure in MM is associated with worse outcome of the disease. We retrospectively analyzed the medical records of 64 patients with MM admitted to our institution during the period January 1992 to December 2012. Abnormal renal function was observed in 24 (37.5%) patients and 17 (26.6%) of them had renal failure; 14 of the 17 (82.4%) of patients with renal failure had Stage III MM. Urine Bence- Jones protein was positive in ten (58.8%) patients with renal failure versus ten (21.3%) patients without renal failure (P = 0.004). Potential precipitating factors of renal failure were determined in nine patients. Renal function normalized in 11 patients with simple measures, while six patients required hemodialysis; one remained dialysis dependent till time of death. Early mortality occurred in five (29.4%) patients with renal failure as compared with two (4.3%) patients in the group without renal failure (P = 0.005). In conclusion, renal failure is associated with a higher tumor burden and Bence-Jones proteinuria in patients with MM. It is reversible in the majority of patients; however, early mortality tends to be higher in patients with persistent renal failure.

  9. Hypogonadism and renal failure: An update.

    PubMed

    Thirumavalavan, Nannan; Wilken, Nathan A; Ramasamy, Ranjith

    2015-01-01

    The prevalence of both hypogonadism and renal failure is increasing. Hypogonadism in men with renal failure carries with it significant morbidity, including anemia and premature cardiovascular disease. It remains unclear whether testosterone therapy can affect the morbidity and mortality associated with renal failure. As such, in this review, we sought to evaluate the current literature addressing hypogonadism and testosterone replacement, specifically in men with renal failure. The articles chosen for this review were selected by performing a broad search using Pubmed, Embase and Scopus including the terms hypogonadism and renal failure from 1990 to the present. This review is based on both primary sources as well as review articles. Hypogonadism in renal failure has a multifactorial etiology, including co-morbid conditions such as diabetes, hypertension, old age and obesity. Renal failure can lead to decreased luteinizing hormone production and decreased prolactin clearance that could impair testosterone production. Given the increasing prevalence of hypogonadism and the potential morbidity associated with hypogonadism in men with renal failure, careful evaluation of serum testosterone would be valuable. Testosterone replacement therapy should be considered in men with symptomatic hypogonadism and renal failure, and may ameliorate some of the morbidity associated with renal failure. Patients with all stages of renal disease are at an increased risk of hypogonadism that could be associated with significant morbidity. Testosterone replacement therapy may reduce some of the morbidity of renal failure, although it carries risk.

  10. Everyday attention failures: an individual differences investigation.

    PubMed

    Unsworth, Nash; McMillan, Brittany D; Brewer, Gene A; Spillers, Gregory J

    2012-11-01

    The present study examined individual differences in everyday attention failures. Undergraduate students completed various cognitive ability measures in the laboratory and recorded everyday attention failures in a diary over the course of a week. The majority of attention failures were failures of distraction or mind wandering in educational contexts (in class or while studying). Latent variable techniques were used to perform analyses, and the results suggested that individual differences in working memory capacity and attention control were related to some but not all everyday attention failures. Furthermore, everyday attention failures predicted SAT scores and partially accounted for the relation between cognitive abilities and SAT scores. These results provide important evidence for individual differences in everyday attention failures as well as for the ecological validity of laboratory measures of working memory capacity and attention control.

  11. The intergenerational transmission of fear of failure.

    PubMed

    Elliot, Andrew J; Thrash, Todd M

    2004-08-01

    The intergenerational transmission of fear of failure was examined in two studies with undergraduates and their parents. Parent-undergraduate concordance in fear of failure was documented for mothers and fathers, controlling for parents' and undergraduate's impression management and self-deceptive enhancement response tendencies. Love withdrawal was validated as a mediator of parent-undergraduate concordance in fear of failure for mothers but not for fathers. Mothers' and fathers' fear of failure was also a positive predictor of undergraduate's adoption of performance-avoidance goals in the classroom, and undergraduate's fear of failure was shown to mediate this relationship. Fathers' fear of failure was also a negative predictor of undergraduate's mastery goal adoption, and this relationship was likewise mediated by undergraduate's fear of failure. The results are discussed in terms of the reorienting of positive, appetitive achievement motivation toward negative, aversive achievement motivation. PMID:15257781

  12. Hydrogen-containing saline attenuates doxorubicin-induced heart failure in rats.

    PubMed

    Wu, Shujing; Zhu, Liqun; Yang, Jing; Fan, Zhixin; Dong, Yanli; Luan, Rui; Cai, Jingjing; Fu, Lu

    2014-08-01

    Interactions between doxorubicin (DOX) and iron generate reactive oxygen species and contribute to DOX-induced heart failure. Hydrogen, as a selective antioxidant, is a promising potential therapeutic option for the treatment of a variety of diseases. Therefore, we investigated the preventive effects of hydrogen treatment on DOX-induced heart failure in rats. We found that cardiac function was significantly improved and that the plasma levels of oxidative-stress markers and myocardial autophagic activity were decreased in animals treated with hydrogen-containing saline. Therefore, we conclude that hydrogen-containing saline may have beneficial effects for doxorubicin-induced heart failure.

  13. Parental failure in captive cotton-top tamarins (Saguinus Oedipus).

    PubMed

    Bardi, M; Petto, A J; Lee-Parritz, D E

    2001-07-01

    Several New World monkey species experience high rates of infant mortality in captivity, and parental failure in the form of infant neglect and abuse is often regarded as one of the leading causes of this problem. We explored a large archival database to assess environmental, familial, and biological variables identified as significant for parental success in previous studies of captive tamarins, through several generations and across several dozen pedigrees. Using a stepwise multiple regression analysis we developed a model including the fewest variables able to identify statistically significant predictors of infant outcome. We found that seven independent variables could predict infant outcome in the colony. The most important appeared to be the presence of helpers with whom parents could share infant carrying. Mother's experience and litter size were two other variables that contributed to a significant extent to explaining parental failure. Moreover, the model showed that there is a measurable contribution to infant outcome due to the health status of both parents. Finally, we found a distinct role for mothers and fathers, and that parental failure follows different patterns for abuse and rejection. PMID:11443631

  14. Executive Dysfunction is Independently Associated with Reduced Functional Independence in Heart Failure

    PubMed Central

    Alosco, Michael L.; Spitznagel, Mary Beth; Raz, Naftali; Cohen, Ronald; Sweet, Lawrence H.; Colbert, Lisa H.; Josephson, Richard; van Dulmen, Manfred; Hughes, Joel; Rosneck, Jim; Gunstad, John

    2016-01-01

    Aims and Objectives To examine the independent association between executive function with instrumental activities of daily living and health behaviors in older adults with heart failure. Background Executive function is an important contributor to functional independence as it consists of cognitive processes needed for decision-making, planning, organizing, and behavioral monitoring. Impairment in this domain is common in heart failure patients and associated with reduced performance of instrumental activities of daily living in many medical and neurological populations. However, the contribution of executive functions to functional independence and healthy lifestyle choices in heart failure patients has not been fully examined. Design Cross-sectional analyses. Methods 175 heart failure patients completed a neuropsychological battery and echocardiogram. Participants also completed the Lawton-Brody instrumental activities of daily living scale and reported current cigarette use. Results Hierarchical regressions revealed reduced executive function was independently associated with worse instrumental activity of daily living performance with a specific association for decreased ability to manage medications. Partial correlations showed executive dysfunction was associated with current cigarette use. Conclusions Our findings suggest that executive dysfunction is associated with poorer functional independence and contributes to unhealthy behaviors in heart failure. Future studies should examine whether heart failure patients benefit from formal organization schemae (i.e., pill organizers) to maintain independence. Relevance to Clinical Practice Screening of executive function in heart failure patients may provide key insight into their ability to perform daily tasks, including management of treatment recommendations. PMID:23650879

  15. 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

  16. Synergistic Failure of BWR Internals

    SciTech Connect

    Ware, Arthur Gates; Chang, T-Y

    1999-10-01

    Boiling Water Reactor (BWR) core shrouds and other reactor internals important to safety are experiencing intergranular stress corrosion cracking (IGSCC). The United States Nuclear Regulatory Commission has followed the problem, and as part of its investigations, contracted with the Idaho National Engineering and Environmental Laboratory to conduct a risk assessment. The overall project objective is to assess the potential consequences and risks associated with the failure of IGSCC-susceptible BWR vessel internals, with specific consideration given to potential cascading and common mode effects. An initial phase has been completed in which background material was gathered and evaluated, and potential accident sequences were identified. A second phase is underway to perform a simplified, quantitative probabilistic risk assessment on a representative high-power BWR/4. Results of the initial study conducted on the jet pumps show that any cascading failures would not result in a significant increase in the core damage frequency. The methodology is currently being extended to other major reactor internals components.

  17. Floods from tailings dam failures.

    PubMed

    Rico, M; Benito, G; Díez-Herrero, A

    2008-06-15

    This paper compiles the available information on historic tailings dam failures with the purpose to establish simple correlations between tailings ponds geometric parameters (e.g., dam height, tailings volume) and the hydraulic characteristics of floods resulting from released tailings. Following the collapse of a mining waste dam, only a part of tailings and polluted water stored at the dam is released, and this outflow volume is difficult to estimate prior the incident. In this study, tailings' volume stored at the time of failure was shown to have a good correlation (r2=0.86) with the tailings outflow volume, and the volume of spilled tailings was correlated with its run-out distance (r2=0.57). An envelope curve was drawn encompassing the majority of data points indicating the potential maximum downstream distance affected by a tailings' spill. The application of the described regression equations for prediction purposes needs to be treated with caution and with support of on-site measurement and observations. However, they may provide a universal baseline approximation on tailing outflow characteristics (even if detailed dam information is unavailable), which is of a great importance for risk analysis purposes.

  18. [Nutrition and chronic renal failure].

    PubMed

    Ayúcar Ruiz de Galarreta, A; Cordero Lorenzana, M L; Martínez-Puga y López, E; Gómez Seijo, A; Escudero Alvarez, E

    2000-01-01

    The causes of malnutrition in chronic terminal kidney failure are reviewed in the situation both before and after dialysis, as are the malnutrition rates in both circumstances and their treatment. Malnutrition has a high prevalence in terminal kidney patients, partly as a result of the therapeutic restriction on calories and proteins, but also due to the metabolic reactions typical of the disease and to anorexia. In patients subjected to dialytical methods, certain other mechanisms are added. In addition to malnutrition, there are alterations in the metabolism of calcium, phosphorus and potassium, as well as lipids, thus limiting nutritional therapy's ability to restore the nutritional status to normal. An awareness of energy expenditure in chronic terminal kidney failure and the consequences of malnutrition have led to new challenges in nutritional therapy, both in the dose and quality of the proteins, with a debate raging over the advantages of ketoanalogues, and also in the methods for providing nutrients. The ideal nutritional method for repletion is oral administration, but this can be enhanced with artificial support such as oral supplements, parenteral nutrition during dialysis or such alternatives as enteral nutrition at home in the case of chronic kidney problems in children, using percutaneous endoscopic gastrostomy (PEG), in order to nourish the patients and minimize growth disorders.

  19. The failure of cancer chemoprevention.

    PubMed

    Potter, John D

    2014-05-01

    Chemoprevention is proposed as a clinical analogue of population prevention, aimed at reducing likelihood of disease progression, not across the population, but in identified high-risk individuals and not by behavioral or lifestyle modification, but by the use of pharmaceutical agents. Cardiovascular chemoprevention is successful via control of hyperlipidemias and hypertension. However, chemoprevention of cancer is an almost universal failure: not only are some results null; even more frequently, there is an excess of disease, including disease that the agents were chosen specifically to reduce. A brief introduction is followed by the evidence for a wide variety of agents and their largely deleterious, sometimes null, and in one case, largely beneficial, consequences as possible chemopreventives. The agents include (i) those that are food derived and their synthetic analogues: β-carotene, folic acid, retinol and retinoids, vitamin E, multivitamin supplements, vitamin C, calcium and selenium and (ii) agents targeted at metabolic and hormonal pathways: statins, estrogen and antagonists, 5α-reductase inhibitors. There are two agents for which there is good evidence of benefit when the strategy is focused on those at defined high risk but where wider application is much more problematic: aspirin and tamoxifen. The major problems with cancer chemoprevention are presented. This is followed by a hypothesis to explain the failure of cancer chemoprevention as an enterprise, arguing that the central tenets that underpin it are flawed and showing why, far from doing good, cancer chemoprevention causes harm.

  20. ZINC AND THE PROOXIDANT HEART FAILURE PHENOTYPE

    PubMed Central

    Efeovbokhan, Nephertiti; Bhattacharya, Syamal K.; Ahokas, Robert A.; Sun, Yao; Guntaka, Ramareddy V.; Gerling, Ivan C.; Weber, Karl T.

    2014-01-01

    Neurohormonal activation with attendant aldosteronism contributes to the clinical appearance of congestive heart failure (CHF). Aldosteronism is intrinsically coupled to Zn2+ and Ca2+ dyshomeostasis, in which consequent hypozincemia compromises Zn2+ homeostasis and Zn2+-based antioxidant defenses that contribute to the CHF prooxidant phenotype. Ionized hypocalcemia leads to secondary hyperparathyroidism with parathyroid hormone-mediated Ca2+ overloading of diverse cells, including cardiomyocytes. When mitochondrial Ca2+ overload exceeds a threshold, myocyte necrosis follows. The reciprocal regulation involving cytosolic free [Zn2+]i as antioxidant and [Ca2+]i as prooxidant that can be uncoupled in favor of Zn2+-based antioxidant defenses. Increased [Zn2+]i acts as a multifaceted antioxidant by: i) inhibiting Ca2+ entry via L-type channels and hence cardioprotectant from the Ca2+-driven mitochondriocentric signal-transducer-effector pathway to nonischemic necrosis; ii) serving as catalytic regulator of Cu/Zn-superoxide dismutase; and iii) activating its cytosolic sensor, metal-responsive transcription factor that regulates the expression of relevant antioxidant defense genes. Albeit present in subnanomolar range, increased cytosolic free [Zn2+]i enhances antioxidant capacity that confers cardioprotection. It can be achieved exogenously by ZnSO4 supplementation or endogenously, using a β3 receptor agonist, (e.g., nebivolol) that enhances NO generation to release inactive cytosolic Zn2+ bound to metallothionein. By recognizing the pathophysiologic relevance of Zn2+ dyshomeostasis in the prooxidant CHF phenotype and by exploiting the pharmacophysiologic potential of [Zn2+]i as antioxidant, vulnerable cardiomyocytes under assault from neurohormonal activation can be protected and the myocardium spared from adverse structural remodeling. PMID:25291496

  1. Endogenous cardiotonic steroids in chronic renal failure

    PubMed Central

    Kolmakova, Elena V.; Haller, Steven T.; Kennedy, David J.; Isachkina, Alina N.; Budny, George V.; Frolova, Elena V.; Piecha, Grzegorz; Nikitina, Elena R.; Malhotra, Deepak; Fedorova, Olga V.; Shapiro, Joseph I.

    2011-01-01

    Background. Previous reports demonstrated that digitalis-like cardiotonic steroids (CTS) contribute to the pathogenesis of end-stage renal disease. The goal of the present study was to define the nature of CTS in patients with chronic kidney disease (CKD) and in partially nephrectomized (PNx) rats. Methods. In patients with CKD and in healthy controls, we determined plasma levels of marinobufagenin (MBG) and endogenous ouabain (EO) and erythrocyte Na/K-ATPase activity in the absence and in the presence of 3E9 anti-MBG monoclonal antibody (mAb) and Digibind. Levels of MBG and EO were also determined in sham-operated Sprague–Dawley rats and in rats following 4 weeks of PNx. Results. In 25 patients with CKD plasma, MBG but not EO was increased (0.86 ± 0.07 versus 0.28 ± 0.02 nmol/L, P < 0.01) and erythrocyte Na/K-ATPase was inhibited (1.24 ± 0.10 versus 2.80 ± 0.09 μmol Pi/mL/h, P < 0.01) as compared to that in 19 healthy subjects. Ex vivo, 3E9 mAb restored Na/K-ATPase in erythrocytes from patients with CKD but did not affect Na/K-ATPase from control subjects. Following chromatographic fractionation of uremic versus normal plasma, a competitive immunoassay based on anti-MBG mAb detected a 3-fold increase in the level of endogenous material having retention time similar to that seen with MBG. A similar pattern of CTS changes was observed in uremic rats. As compared to sham-operated animals, PNx rats exhibited 3-fold elevated levels of MBG but not that of EO. Conclusions. In chronic renal failure, elevated levels of a bufadienolide CTS, MBG, contribute to Na/K-ATPase inhibition and may represent a potential target for therapy. PMID:21292813

  2. Regional Hippocampal Damage in Heart Failure

    PubMed Central

    Woo, Mary A.; Ogren, Jennifer A.; Abouzeid, Christiane M.; Macey, Paul M.; Sairafian, Kevin G.; Saharan, Priya S.; Thompson, Paul M.; Fonarow, Gregg C.; Hamilton, Michele A.; Harper, Ronald M.; Kumar, Rajesh

    2015-01-01

    Aims Heart failure (HF) patients show cognitive and mood impairments, including short-term memory loss and depression, adversely impacting quality of life and self-care management. Brain regions, including the hippocampus, a structure significantly involved in memory and mood, show injury in HF, but the integrity of specific hippocampal subregions is unclear. Methods and results To assess regional hippocampal volume loss, we evaluated 17 HF patients (mean age ± SD, 54.4 ± 2.0 years; 12 male, LVEF 28.3 ± 6.8%; NYHA Class II/III 94%/6%) and 34 healthy control subjects (52.3 ± 1.3 years; 24 male) using high-resolution T1-weighted magnetic resonance imaging and evaluated localized surface changes with morphometric procedures. Hippocampi were manually outlined, and volumes calculated from normalized tracings. Volume differences between groups were assessed by two-sample t-tests, and regional differences were assessed by surface morphometry. HF patients exhibited smaller hippocampal volumes than controls (Right: 3060±146 vs. 3478±94 mm3; p = 0.02, Left: 3021±145 vs. 3352±98 mm3; p = 0.06). Volume reductions were detected principally in CA1, an area integral to an array of learning and memory functions, as well as in mid- to posterior CA3 and subiculum. Conclusion The hippocampus shows regional volume reduction in HF, which may contribute to short-term memory loss and depression associated with the condition. PMID:25704495

  3. Blood flow dynamics in heart failure

    NASA Technical Reports Server (NTRS)

    Shoemaker, J. K.; Naylor, H. L.; Hogeman, C. S.; Sinoway, L. I.

    1999-01-01

    BACKGROUND: Exercise intolerance in heart failure (HF) may be due to inadequate vasodilation, augmented vasoconstriction, and/or altered muscle metabolic responses that lead to fatigue. METHODS AND RESULTS: Vascular and metabolic responses to rhythmic forearm exercise were tested in 9 HF patients and 9 control subjects (CTL) during 2 protocols designed to examine the effect of HF on the time course of oxygen delivery versus uptake (protocol 1) and on vasoconstriction during exercise with 50 mm Hg pressure about the forearm to evoke a metaboreflex (protocol 2). In protocol 1, venous lactate and H+ were greater at 4 minutes of exercise in HF versus CTL (P<0.05) despite similar blood flow and oxygen uptake responses. In protocol 2, mean arterial pressure increased similarly in each group during ischemic exercise. In CTL, forearm blood flow and vascular conductance were similar at the end of ischemic and ambient exercise. In HF, forearm blood flow and vascular conductance were reduced during ischemic exercise compared with the ambient trial. CONCLUSIONS: Intrinsic differences in skeletal muscle metabolism, not vasodilatory dynamics, must account for the augmented glycolytic metabolic responses to moderate-intensity exercise in class II and III HF. The inability to increase forearm vascular conductance during ischemic handgrip exercise, despite a normal pressor response, suggests that enhanced vasoconstriction of strenuously exercising skeletal muscle contributes to exertional fatigue in HF.

  4. [Carbonyl stress and oxidatively modified proteins in chronic renal failure].

    PubMed

    Bargnoux, A-S; Morena, M; Badiou, S; Dupuy, A-M; Canaud, B; Cristol, J-P

    2009-01-01

    Oxidative stress is commonly observed in chronic renal failure patients resulting from an unbalance between overproduction of reactive oxygen species and impairement of defense mechanisms. Proteins appear as potential targets of uremia-induced oxidative stress and may undergo qualitative modifications. Proteins could be directly modified by reactive oxygen species which leads to amino acid oxydation and cross-linking. Proteins could be indirectly modified by reactive carbonyl compounds produced by glycoxidation and lipo-peroxidation. The resulting post-traductional modifications are known as carbonyl stress. In addition, thiols could be oxidized or could react with homocystein leading to homocysteinylation. Finally, tyrosin could be oxidized by myeloperoxidase leading to advanced oxidative protein products (AOPP). Oxidatively modified proteins are increased in chronic renal failure patients and may contribute to exacerbate the oxidative stress/inflammation syndrome. They have been involved in long term complications of uremia such as amyloidosis and accelerated atherosclerosis. PMID:19297289

  5. Acute renal failure following binge drinking and nonsteroidal antiinflammatory drugs.

    PubMed

    Wen, S F; Parthasarathy, R; Iliopoulos, O; Oberley, T D

    1992-09-01

    Two college students who developed reversible acute deterioration in renal function following binge drinking of beer and the use of nonsteroidal antiinflammatory drugs (NSAIDs) are reported. Both patients presented with back and flank pain with muscle tenderness, but showed no evidence of overt rhabdomyolysis. The first case had marked renal failure, with a peak serum creatinine reaching 575 mumol/L (6.5 mg/dL), and acute tubular necrosis was documented by renal biopsy. The second case had only modest elevation in serum creatinine, and renal function rapidly improved on rehydration. The contribution of the potential muscle damage associated with alcohol ingestion to the changes in renal function in these two cases is not clear. However, the major mechanism for the acute renal failure was thought to be related to inhibition of renal prostaglandin synthesis in the face of compromised renal hemodynamics secondary to alcohol-induced volume depletion. PMID:1519610

  6. Critical diaphragm failure in sudden infant death syndrome.

    PubMed

    Siren, Pontus Max Axel; Siren, Matti Juhani

    2011-05-01

    Sudden infant death syndrome (SIDS) is the leading cause of death in infants between the ages of 1 and 12 months in developed countries. SIDS is by definition a diagnosis of exclusion, and its mechanism of action is unknown. The SIDS-Critical Diaphragm Failure (CDF) hypothesis postulates that the cause of death in SIDS is respiratory failure caused by CDF. Four principal risk factors contribute to CDF in young infants: undeveloped respiratory muscles, non-lethal infections, prone resting position, and REM sleep. Even relatively minor infections can cause an acute and significant reduction in diaphragm force generation capacity that in conjunction with other risk factors can precipitate CDF. CDF-induced acute muscle weakness leaves few, if any pathological marks on the affected tissue.Understanding the underlying mechanism of SIDS may help in formulating new approaches to child care that can help to further reduce the incidence of SIDS. PMID:21222555

  7. Acute kidney injury in acute liver failure: a review.

    PubMed

    Moore, Joanna K; Love, Eleanor; Craig, Darren G; Hayes, Peter C; Simpson, Kenneth J

    2013-11-01

    Acute liver failure is a rare and often devastating condition consequent on massive liver cell necrosis that frequently affects young, previously healthy individuals resulting in altered cognitive function, coagulopathy and peripheral vasodilation. These patients frequently develop concurrent acute kidney injury (AKI). This abrupt and sustained decline in renal function, through a number of pathogenic mechanisms such as renal hypoperfusion, direct drug-induced nephrotoxicity or sepsis/systemic inflammatory response contributes to increased morbidity and is strongly associated with a worse prognosis. Improved understanding of the pathophysiology AKI in the context of acute liver failure may be beneficial in a number of areas; the development of new and sensitive biomarkers of renal dysfunction, refining prognosis and organ allocation, and ultimately leading to the development of novel treatment strategies, these issues are discussed in more detail in this expert review.

  8. Patient Characteristics Predicting Readmission Among Individuals Hospitalized for Heart Failure

    PubMed Central

    O'Connor, Melissa; Murtaugh, Christopher M.; Shah, Shivani; Barrón-Vaya, Yolanda; Bowles, Kathryn H.; Peng, Timothy R.; Zhu, Carolyn W.; Feldman, Penny H.

    2015-01-01

    Heart failure is difficult to manage and increasingly common with many individuals experiencing frequent hospitalizations. Little is known about patient factors consistently associated with hospital readmission. A literature review was conducted to identify heart failure patient characteristics, measured before discharge, that contribute to variation in hospital readmission rates. Database searches yielded 950 potential articles, of which 34 studies met inclusion criteria. Patient characteristics generally have a very modest effect on all-cause or heart failure–related readmission within 7 to 180 days of index hospital discharge. A range of cardiac diseases and other comorbidities only minimally increase readmission rates. No single patient characteristic stands out as a key contributor across multiple studies underscoring the challenge of developing successful interventions to reduce readmissions. Interventions may need to be general in design with the specific intervention depending on each patient's unique clinical profile. PMID:26180045

  9. Register of experts for information on mechanics of structural failure

    NASA Technical Reports Server (NTRS)

    Carpenter, J. L., Jr.; Stuhrke, W. F.

    1975-01-01

    This register is comprised of a list of approximately 300 experts from approximately 90 organizations who have published results of theoretical and/or experimental research related to six problem areas in the mechanics of structural failure: (1) life prediction for structural materials, (2) fracture toughness testing, (3) fracture mechanics analysis; (4) hydrogen embrittlement; (5) protective coatings; and (6) composite materials. The criteria for the selection of names for the register are recent contributions to the literature, participation in or support of relevant research programs, and referral by peers. Each author included is listed by organizational affiliation, address, and principal field of expertise. The purpose of the register is to present, in easy reference form, sources for dependable information regarding failure modes and mechanisms of aerospace structures. The register includes two indexes; an alphabetical listing of the experts and an alphabetical listing of the organizations with whom they are affiliated.

  10. [Diuretics in heart failure and Karl Popper's turkey].

    PubMed

    Cice, Gennaro

    2015-12-01

    Heart failure and renal failure often coexist in the same patient. This condition is commonly referred to as cardiorenal syndrome. When this occurs, patient survival worsens significantly with increasing degree of renal dysfunction. Management of this complex patient poses treatment challenges because of unstable hemodynamics (the problem is to reduce congestion without affecting organ perfusion) and very high mid-term in-hospital mortality. Congestion is a typical feature of this syndrome, and use of diuretics is mandatory. Loop diuretics should be administered first. However, poor attention to pharmacodynamic and pharmacokinetic properties of loop diuretics may contribute to the development of diuretic resistance leading to iatrogenic hyponatremia. Accordingly, emphasis is given to the importance of sequential nephron blockade to reduce the number of non-responder patients to diuretics and to recognize a possible role for acquaretics.

  11. Register of experts for information on mechanics of structural failure

    NASA Technical Reports Server (NTRS)

    Carpenter, J. L., Jr.; Moya, N.

    1973-01-01

    A list of approximately 150 experts from approximately 60 organizations who have published results of theoretical and/or experimental research related to six problem areas in the mechanics of structural failure is presented. Each author included is listed by organizational affiliation, address and principal field of expertise. The initial criteria for the selection of names for the register are recent contributions to the literature, participation in or support of relevant research programs, and referral by peers. The purpose of the register is to present, in easy reference form, sources for dependable information regarding failure modes and mechanisms of aerospace structures. The Register includes two indexes: an alphabetical listing of the experts and an alphabetical listing of the organizations with whom they are affiliated.

  12. Analysis of sucker rod and sinkerbar failures

    SciTech Connect

    Waggoner, J.R.; Buchheit, R.G.

    1992-12-31

    This paper presents results from a study to analyze the performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, structural finite element analysis, and detailed failure data collection. Metallography demonstrated that microstructure of steel bar stock needs to be considered. Current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding. Finite element analysis of the threaded connection identifies stress and fatigue concentrations and quantitatively assesses the performance and failure of coupling designs under a variety of loading conditions. Subcritical fractures observed in the metallography are also suggested by the calculated stress distribution in the threaded coupling. Failure data illustrates both magnitude and frequency of the failures, as well as categorizing the suspected cause of failure. This failure information alone can reduce failures by indicating specific problem areas. These results are expected to yield improved choice of metal bar stock, thread design, and make-up practices which can reduce sucker rod failures.

  13. Analysis of sucker rod and sinkerbar failures

    SciTech Connect

    Waggoner, J.R.; Buchheit, R.G.

    1992-01-01

    This paper presents results from a study to analyze the performance and failures of the sucker rod/sinkerbar string used in beam-pumping operations through metallography, structural finite element analysis, and detailed failure data collection. Metallography demonstrated that microstructure of steel bar stock needs to be considered. Current specification based on tensile strength, or yield strength, may not be appropriate since failure occurs because of fatigue and not yielding. Finite element analysis of the threaded connection identifies stress and fatigue concentrations and quantitatively assesses the performance and failure of coupling designs under a variety of loading conditions. Subcritical fractures observed in the metallography are also suggested by the calculated stress distribution in the threaded coupling. Failure data illustrates both magnitude and frequency of the failures, as well as categorizing the suspected cause of failure. This failure information alone can reduce failures by indicating specific problem areas. These results are expected to yield improved choice of metal bar stock, thread design, and make-up practices which can reduce sucker rod failures.

  14. Postbuckling failure of composite plates with holes

    NASA Technical Reports Server (NTRS)

    Lee, H. H.; Hyer, M. W.

    1992-01-01

    This paper summarizes a study focused on understanding the failure mechanisms present in a plate with a centrally located circular hole loaded inplane into the postbuckling range of deflections. The study was numerical and experimental in nature and had as a goal the a priori prediction of failure using existing failure data from several sources, together with a stress analysis. The maximum stress failure criterion was used to predict failure and both intra- and interlaminar stresses were considered. Four laminates were considered. The phenomenon of modal interaction, or the jumping from one deformed configuration to another, is discussed. With this jumping, the plate configuration may change from one half-wave in the loading direction to two half-waves in the loading direction. The study concludes that the failure in (+/-45/0/90)2s and (+/-45/2(2))2s laminates is due to fiber compression failure and is predictable. The failure load is, for the most part, independent of response configuration. The (+/-45/0/(6))s laminate fails due to interlaminar shear along the simple support, while the response and failure of the (+/-45)4s laminate is governed to a large degree by material nonlinearities and progressive failure.

  15. Plasma Glutamine Concentrations in Liver Failure

    PubMed Central

    Helling, Gunnel; Wahlin, Staffan; Smedberg, Marie; Pettersson, Linn; Tjäder, Inga; Norberg, Åke; Rooyackers, Olav; Wernerman, Jan

    2016-01-01

    Background Higher than normal plasma glutamine concentration at admission to an intensive care unit is associated with an unfavorable outcome. Very high plasma glutamine levels are sometimes seen in both acute and chronic liver failure. We aimed to systematically explore the relation between different types of liver failure and plasma glutamine concentrations. Methods Four different groups of patients were studies; chronic liver failure (n = 40), acute on chronic liver failure (n = 20), acute fulminant liver failure (n = 20), and post-hepatectomy liver failure (n = 20). Child-Pugh and Model for End-stage Liver Disease (MELD) scores were assessed as indices of liver function. All groups except the chronic liver failure group were followed longitudinally during hospitalisation. Outcomes were recorded up to 48 months after study inclusion. Results All groups had individuals with very high plasma glutamine concentrations. In the total group of patients (n = 100), severity of liver failure correlated significantly with plasma glutamine concentration, but the correlation was not strong. Conclusion Liver failure, regardless of severity and course of illness, may be associated with a high plasma glutamine concentration. Further studies are needed to understand whether high glutamine levels should be regarded as a biomarker or as a contributor to symptomatology in liver failure. PMID:26938452

  16. Avicenna's contribution to cardiology.

    PubMed

    Chamsi-Pasha, Mohammed A R; Chamsi-Pasha, Hassan

    2014-01-01

    Ibn Sina, known in the West as Avicenna, was the most famous and influential of all the Islamic philosopher-scientists. His most important medical works are the Canon of Medicine medical encyclopedia and a treatise on cardiac drugs. His Canon of Medicine remained the standard text in both the East and West until the 16(th) century. Avicenna's description of cardiac diseases was logically presented perhaps for the first time in the history of medicine. Avicenna was the first to describe carotid sinus hypersensitivity, which presents with vasovagal syncope. He was a pioneer in pulsology and the first correct explanation of pulsation was given by Avicenna, after he refined Galen's theory of the pulse. Besides, he discussed the action of available drugs on the heart in details and mentioned their indications and contraindications. In conclusion, Avicenna made important contributions to cardiology. This article describes some of his contributions in this field. PMID:24678465

  17. Avicenna's contribution to cardiology

    PubMed Central

    Chamsi-Pasha, Mohammed A.R.; Chamsi-Pasha, Hassan

    2014-01-01

    Ibn Sina, known in the West as Avicenna, was the most famous and influential of all the Islamic philosopher-scientists. His most important medical works are the Canon of Medicine medical encyclopedia and a treatise on cardiac drugs. His Canon of Medicine remained the standard text in both the East and West until the 16th century. Avicenna's description of cardiac diseases was logically presented perhaps for the first time in the history of medicine. Avicenna was the first to describe carotid sinus hypersensitivity, which presents with vasovagal syncope. He was a pioneer in pulsology and the first correct explanation of pulsation was given by Avicenna, after he refined Galen's theory of the pulse. Besides, he discussed the action of available drugs on the heart in details and mentioned their indications and contraindications. In conclusion, Avicenna made important contributions to cardiology. This article describes some of his contributions in this field. PMID:24678465

  18. NADPH Oxidases in Heart Failure: Poachers or Gamekeepers?

    PubMed Central

    Zhang, Min; Perino, Alessia; Ghigo, Alessandra; Hirsch, Emilio

    2013-01-01

    Abstract Significance: Oxidative stress is involved in the pathogenesis of heart failure but clinical antioxidant trials have been unsuccessful. This may be because effects of reactive oxygen species (ROS) depend upon their source, location, and concentration. Nicotinamide adenine dinucleotide phosphate oxidase (Nox) proteins generate ROS in a highly regulated fashion and modulate several components of the heart failure phenotype. Recent Advances: Two Nox isoforms, Nox2 and Nox4, are expressed in the heart. Studies using gene-modified mice deficient in Nox2 activity indicate that Nox2 activation contributes to angiotensin II–induced cardiomyocyte hypertrophy, atrial fibrillation, and the development of interstitial fibrosis but may also positively modulate physiological excitation-contraction coupling. Nox2 contributes to myocyte death under stress situations and plays important roles in postmyocardial infarction remodeling, in part by modulating matrix metalloprotease activity. In contrast to Nox2, Nox4 is constitutively active at a low level and induces protective effects in the heart under chronic stress, for example, by maintaining myocardial capillary density. However, high levels of Nox4 could have detrimental effects. Critical Issues: The effects of Nox proteins during the development of heart failure likely depend upon the isoform, activation level, and cellular distribution, and may include beneficial as well as detrimental effects. More needs to be learnt about the precise regulation of abundance and biochemical activity of these proteins in the heart as well as the downstream signaling pathways that they regulate. Future Directions: The development of specific approaches to target individual Nox isoforms and/or specific cell types may be important for the achievement of therapeutic efficacy in heart failure. Antioxid. Redox Signal. 18, 1024–1041. PMID:22747566

  19. Exhausting Multiple Hemodialysis Access Failures

    PubMed Central

    Bolleke, Erjola; Seferi, Saimir; Rroji, Merita; Idrizi, Alma; Barbullushi, Myftar; Thereska, Nestor

    2014-01-01

    ABSTRACT Introduction: Vascular access is often considered the Achilles heel the of hemodialysis because of its impact on morbidity, all cause mortality and finally costs of these patients. The most common complication of permanent hemodialysis (HD) vascular access is thrombosis, with some cases being related to hypercoagulability states. Antiphospholipid antibody syndrome (APAS) is a cause of increased thrombotic tendency, and this may complicate the management of such patients on HD. Case report: We describe a 41-year-old woman with end stage renal disease (ESRD) from Adult Polycystic Kidney Disease who was referred to our tertiary care center for treatment and selection of renal replacement therapy form. It was thought to initiate with peritoneal dialysis considering her actual conditions. She was putted on hemodialysis for several sessions, and a subclavian cathether was her first vascular access. The surgeon created an arterio-venous fistula which did not mature. After the implantation of the peritoneal cathether she started peritoneal dialysis and continued living with that for 2 years. She felt exhausted and because of a grave peritonitis episode accompanied with procedure failure and a long hospitalization she was transferred to hemodialysis. Renal transplantation was not possible because she didn’t have a kidney donation. She was maintained on regular HD, but her dialysis care was complicated by recurrent vascular access failures. She had multiple interventions for arterio-venous fistulas and grafts but almost all of them failed due to thrombosis to the extent that only one access site was available for her routine renal replacement treatment. A thorough thrombophilia screen confirmed the presence of antiphospholipid antibodies. A diagnosis of APAS was made and she was anticoagulated with warfarin. The AVG made in this last available site is still working from 18 months. If it fails we have no answers and solutions for her. Conclusion: The presence of

  20. Abstracts of contributed papers

    SciTech Connect

    Not Available

    1994-08-01

    This volume contains 571 abstracts of contributed papers to be presented during the Twelfth US National Congress of Applied Mechanics. Abstracts are arranged in the order in which they fall in the program -- the main sessions are listed chronologically in the Table of Contents. The Author Index is in alphabetical order and lists each paper number (matching the schedule in the Final Program) with its corresponding page number in the book.

  1. Do deglaciated mountainslopes contribute significantly to paraglacial sediment fluxes?

    NASA Astrophysics Data System (ADS)

    Cossart, Etienne

    2013-04-01

    Current models of paraglacial sediment generation and transport (Ballantyne, 2002 & 2003) are general in nature; they are probably inaccurate for many specific locations because of the wide range in local or regional geomorphic conditions encountered around the globe. One of the conditions that varies from place to place is the pattern of paraglacial landsliding; it varies in both the magnitude, scale, and timing, and therefore has variable influence on sediment generation. Another condition that varies is the sediment connectivity between slopes and the fluvial system; this can vary due to differences in topography, hydrologic regimes, or transient sediment buffers such as landslide dams. In this paper, we examine the extent to which variability in paraglacial landslide patterns and sediment connectivity may affect the applicability of the general paraglacial model. To achieve this we draw on both existing literature and our field experience from the European Alps and Iceland. Sediment generation and pathways, as influenced by post-glacial collapse of mountain slopes in particular, are studied in three steps. First, the processes involved in rock failure are identified and their possible influence on mass-movement locations at different spatial scales in various places is discussed. This comparison reveals a variable pattern of paraglacial landslide distribution, and allows the local/regional controlling parameters to be identified. Second, the rate of triggering of mass-movement over time is roughly assessed in various settings based on a review of recently published data. This comparison aims to identify typical temporal-models for slope evolution through the time elapsed since deglaciation. Third, an attempt is made to assess the contribution of landsliding to the whole paraglacial cascading system by evaluating the somewhat contradictory findings and assertions from previous authors: Some authors have argued for a high sediment yield at catchment sinks in

  2. Internal Progressive Failure in Deep-Seated Landslides

    NASA Astrophysics Data System (ADS)

    Yerro, Alba; Pinyol, Núria M.; Alonso, Eduardo E.

    2016-06-01

    Except for simple sliding motions, the stability of a slope does not depend only on the resistance of the basal failure surface. It is affected by the internal distortion of the moving mass, which plays an important role on the stability and post-failure behaviour of a landslide. The paper examines the stability conditions and the post-failure behaviour of a compound landslide whose geometry is inspired by one of the representative cross-sections of Vajont landslide. The brittleness of the mobilized rock mass was described by a strain-softening Mohr-Coulomb model, whose parameters were derived from previous contributions. The analysis was performed by means of a MPM computer code, which is capable of modelling the whole instability procedure in a unified calculation. The gravity action has been applied to initialize the stress state. This step mobilizes part of the strength along a shearing band located just above the kink of the basal surface, leading to the formation a kinematically admissible mechanism. The overall instability is triggered by an increase of water level. The increase of pore water pressures reduces the effective stresses within the slope and it leads to a progressive failure mechanism developing along an internal shearing band which controls the stability of the compound slope. The effect of the basal shearing resistance has been analysed during the post-failure stage. If no shearing strength is considered (as predicted by a thermal pressurization analysis), the model predicts a response similar to actual observations, namely a maximum sliding velocity of 25 m/s and a run-out close to 500 m.

  3. Radiocontrast-induced renal failure

    SciTech Connect

    Misson, R.T.; Cutler, R.E.

    1985-05-01

    Review of the literature concerning contrast-induced renal dysfunction shows that the currently used agents are remarkably safe with careful patient selection. Clinically apparent kidney failure after their use is essentially nonexistent in those without preexistent renal insufficiency. The incidence rises rapidly in those with azotemia from any cause, however, and diabetic persons with nephropathy are perhaps at special risk. Vigorous volume expansion is possibly effective as a preventive measure and may attenuate adverse effects in those in whom postcontrast dysfunction occurs. New agents are becoming available. It is not yet known if these will prove safer or cost-effective. They have some experimentally demonstrated and theoretical advantages over the presently used agents. 58 references, 1 figure, 2 tables.

  4. Heart Failure Update: Outpatient Management.

    PubMed

    Wojnowich, Katherine; Korabathina, Ravi

    2016-03-01

    Outpatient management of heart failure (HF) is aimed at treating symptoms and preventing hospitalizations and readmissions. Management is initiated in a stepwise approach. Blockade of the renin-angiotensin system is a cornerstone of therapy and should be started, along with beta blockers, as soon as the diagnosis of HF is made. Other drugs, including diuretics, aldosterone antagonists, hydralazine, and nitrates, may be added based on symptoms and American College of Cardiology/American Heart Association stage. Despite a great interest in and theoretical benefit of naturoceutical products in the mitigation of oxidative stress and HF progression, none has been proven to be beneficial, and concerns exist regarding their interactions with standard HF drugs. Other nonpharmacologic interventions, including sodium restriction, regular exercise, and/or cardiac rehabilitation, should be initiated at diagnosis. HF often is progressive, and clinicians should be aware of late stage management options, including implantable devices, cardiac transplantation, and hospice care. PMID:26974001

  5. Addressing Failures in Exascale Computing

    SciTech Connect

    Snir, Marc; Wisniewski, Robert; Abraham, Jacob; Adve, Sarita; Bagchi, Saurabh; Balaji, Pavan; Belak, J.; Bose, Pradip; Cappello, Franck; Carlson, Bill; Chien, Andrew; Coteus, Paul; DeBardeleben, Nathan; Diniz, Pedro; Engelmann, Christian; Erez, Mattan; Fazzari, Saverio; Geist, Al; Gupta, Rinku; Johnson, Fred; Krishnamoorthy, Sriram; Leyffer, Sven; Liberty, Dean; Mitra, Subhasish; Munson, Todd; Schreiber, Rob; Stearley, Jon; Van Hensbergen, Eric

    2014-01-01

    We present here a report produced by a workshop on Addressing failures in exascale computing' held in Park City, Utah, 4-11 August 2012. The charter of this workshop was to establish a common taxonomy about resilience across all the levels in a computing system, discuss existing knowledge on resilience across the various hardware and software layers of an exascale system, and build on those results, examining potential solutions from both a hardware and software perspective and focusing on a combined approach. The workshop brought together participants with expertise in applications, system software, and hardware; they came from industry, government, and academia, and their interests ranged from theory to implementation. The combination allowed broad and comprehensive discussions and led to this document, which summarizes and builds on those discussions.

  6. Addressing failures in exascale computing

    SciTech Connect

    Snir, Marc; Wisniewski, Robert W.; Abraham, Jacob A.; Adve, Sarita; Bagchi, Saurabh; Balaji, Pavan; Belak, Jim; Bose, Pradip; Cappello, Franck; Carlson, William; Chien, Andrew A.; Coteus, Paul; Debardeleben, Nathan A.; Diniz, Pedro; Engelmann, Christian; Erez, Mattan; Saverio, Fazzari; Geist, Al; Gupta, Rinku; Johnson, Fred; Krishnamoorthy, Sriram; Leyffer, Sven; Liberty, Dean; Mitra, Subhasish; Munson, Todd; Schreiber, Robert; Stearly, Jon; Van Hensbergen, Eric

    2014-05-01

    We present here a report produced by a workshop on “Addressing Failures in Exascale Computing” held in Park City, Utah, August 4–11, 2012. The charter of this workshop was to establish a common taxonomy about resilience across all the levels in a computing system; discuss existing knowledge on resilience across the various hardware and software layers of an exascale system; and build on those results, examining potential solutions from both a hardware and software perspective and focusing on a combined approach. The workshop brought together participants with expertise in applications, system software, and hardware; they came from industry, government, and academia; and their interests ranged from theory to implementation. The combination allowed broad and comprehensive discussions and led to this document, which summarizes and builds on those discussions.

  7. Etude de la photosensibilite dans la silice implantee avec des ions de haute energie

    NASA Astrophysics Data System (ADS)

    Verhaegen, Marc

    La photosensibilite est la propriete par laquelle une materiau donne voit son indice de refraction changer sous l'effet d'une exposition lumineuse. Malgre le nombre croissant de dispositif base sur ce phenomene, les mecanismes a la base de la photosensibilite sont encore debattus. Nous apportons dans cette these un eclairage original sur ce sujet en etudiant la matrice de silice pure non dopee rendue photosensible par implantation d'ion de haute energie. L'implantation d'ions silicium de S MeV modifie l'indice de refraction principalement en densifiant une couche mince dont l'epaisseur est de l'ordre de quelques microns. Nos mesures montrent qu'un guide plan supportant les modes TEi et TMi (i = 0,1) est forme et que l'indice effectif du mode TE0 suit l'evolution de la densification en fonction de la dose de silicium implantee. Nous montrerons egalement que l'augmentation d'indice et la densification produites par implantation atteignent un palier pour une dose de 3 x 1014Si/cm 2, alors que la production de defauts par implantation atteint son palier pour une dose plus faible d'un ordre de grandeur soit 3 x 1013Si/cm2. Le profil d'indice longitudinal produit par l'implantation ionique est calcule a partir des mesures des indices effectifs des modes guides. Ce profil suggere que l'augmentation d'indice comprend une contribution dues collisions et une contribution dues aux pertes d'energie par ionisation. La contribution des pertes par ionisation influence significativement le profil d'indice pour des valeurs de pertes d'energie par unite de longueur (dE/dx) de l'ordre de 2 keV/nm. Lorsque la silice implantee est soumise a un rayonnement ultraviolet d'un laser a excimeres, il en resulte une diminution d'indice de refraction de l'ordre de 10-3 avec une efficacite plus grande si la longueur d'onde d'exposition est 193nm (ArF) plutot que 248nm (KrF). Deux regimes d'exposition lumineuse de la silice implantee a 193nm sont observes. Le premier regime produit une diminution

  8. Fault failure with moderate earthquakes

    USGS Publications Warehouse

    Johnston, M.J.S.; Linde, A.T.; Gladwin, M.T.; Borcherdt, R.D.

    1987-01-01

    High resolution strain and tilt recordings were made in the near-field of, and prior to, the May 1983 Coalinga earthquake (ML = 6.7, ?? = 51 km), the August 4, 1985, Kettleman Hills earthquake (ML = 5.5, ?? = 34 km), the April 1984 Morgan Hill earthquake (ML = 6.1, ?? = 55 km), the November 1984 Round Valley earthquake (ML = 5.8, ?? = 54 km), the January 14, 1978, Izu, Japan earthquake (ML = 7.0, ?? = 28 km), and several other smaller magnitude earthquakes. These recordings were made with near-surface instruments (resolution 10-8), with borehole dilatometers (resolution 10-10) and a 3-component borehole strainmeter (resolution 10-9). While observed coseismic offsets are generally in good agreement with expectations from elastic dislocation theory, and while post-seismic deformation continued, in some cases, with a moment comparable to that of the main shock, preseismic strain or tilt perturbations from hours to seconds (or less) before the main shock are not apparent above the present resolution. Precursory slip for these events, if any occurred, must have had a moment less than a few percent of that of the main event. To the extent that these records reflect general fault behavior, the strong constraint on the size and amount of slip triggering major rupture makes prediction of the onset times and final magnitudes of the rupture zones a difficult task unless the instruments are fortuitously installed near the rupture initiation point. These data are best explained by an inhomogeneous failure model for which various areas of the fault plane have either different stress-slip constitutive laws or spatially varying constitutive parameters. Other work on seismic waveform analysis and synthetic waveforms indicates that the rupturing process is inhomogeneous and controlled by points of higher strength. These models indicate that rupture initiation occurs at smaller regions of higher strength which, when broken, allow runaway catastrophic failure. ?? 1987.

  9. Pediatric Heart Failure in the Developing World.

    PubMed

    Ramakrishnan, Sivasubramanian

    2014-01-01

    The exact prevalence of heart failure among children of developing countries is not known, as the data is limited. The relative frequency of different causes of pediatric heart failure varies widely across different countries and even among different parts of large countries like India. Children of developing countries face a double burden of etiologies. Conditions such us congenital heart disease, myocarditis and cardiomyopathies are common causes of pediatric of heart failure. In addition, diseases like rheumatic heart disease, nutritional deficiencies, and other tropical diseases also result in heart failure among children of the developing countries. However, most of the developing countries have low resources and hence management of pediatric heart failure becomes challenging. Advanced therapies for heart failure are rarely used in children of developing countries and cardiac transplant remains a distant dream.

  10. A review of macroscopic ductile failure criteria.

    SciTech Connect

    Corona, Edmundo; Reedlunn, Benjamin

    2013-09-01

    The objective of this work was to describe several of the ductile failure criteria com- monly used to solve practical problems. The following failure models were considered: equivalent plastic strain, equivalent plastic strain in tension, maximum shear, Mohr- Coulomb, Wellman's tearing parameter, Johnson-Cook and BCJ MEM. The document presents the main characteristics of each failure model as well as sample failure predic- tions for simple proportional loading stress histories in three dimensions and in plane stress. Plasticity calculations prior to failure were conducted with a simple, linear hardening, J2 plasticity model. The resulting failure envelopes were plotted in prin- cipal stress space and plastic strain space, where the dependence on stress triaxiality and Lode angle are clearly visible. This information may help analysts select a ductile fracture model for a practical problem and help interpret analysis results.

  11. Analyzing failures: the problems and the solutions

    SciTech Connect

    Goel, V.S.

    1986-01-01

    Papers are presented on a failure analysis of a large centrifugal blower, field fractures in heavy equipment, a failure analysis of a liquid propane gas cylinder, an analysis of helicopter blade fatigue fracture by digital fractographic imaging analysis, and the influence of failure analyses on materials technology and design. Also considered are an analysis of aircraft component failures, the growth of short cracks in IN718, the improper fabrication of rotating blades (resulting in premature failure), and low cycle thermal fatigue and fracture of reinforced piping. Other topics include a nonlinear finite element analysis of stress concentration at high temperature, the inelastic analysis of a hot spot on a heavy vessel wall, the accuracy and precision of mechanical test data generated using computerized testing systems, and maintenance related failures.

  12. Failure analysis issues in microelectromechanical systems (MEMS).

    SciTech Connect

    Walraven, Jeremy Allen

    2005-07-01

    Failure analysis and device characterization of MEMS components are critical steps in understanding the root causes of failure and improving device performance. At the wafer and die level these tasks can be performed with little or no sample preparation. Larger challenges occur after fabrication when the device is packaged, capped, sealed, or otherwise obstructed from view. The challenges and issues of MEMS failure analysis lie in identifying the root cause of failure for these packaged, capped, and sealed devices without perturbing the device or its immediate environment. Novel methods of gaining access to the device or preparing the device for analysis are crucial to accurately determining the root cause of failure. This paper will discuss issues identified in performing root cause failure analysis of packaged MEMS devices, as well as the methods employed to analyze them.

  13. Failure analyses of composite bolted joints

    NASA Technical Reports Server (NTRS)

    Wilson, D. W.; Gillespie, J. W.; York, J. L.; Pipes, R. B.

    1980-01-01

    The complex failure behavior exhibited by bolted joints of graphite epoxy (Hercules AS/3501) was investigated for the net tension, bearing and shearout failure modes using combined analytical and experimental techniques. Plane stress, linear elastic, finite element methods were employed to determine the two dimensional state of stress resulting from a loaded hole in a finite width, semiinfinite strip. The stresses predicted by the finite element method were verified by experiment to lend credence to the analysis. The influence of joint geometric parameters on the state of stress and resultant strength of the joint was also studied. The resulting functional relationships found to exist between bolted joint strength and the geometric parameters, were applied in the formulation of semiempirical strength models for the basic failure modes. A point stress failure criterion was successfully applied as the failure criterion for the net tension and shearout failure modes.

  14. Light water reactor lower head failure analysis

    SciTech Connect

    Rempe, J.L.; Chavez, S.A.; Thinnes, G.L.

    1993-10-01

    This document presents the results from a US Nuclear Regulatory Commission-sponsored research program to investigate the mode and timing of vessel lower head failure. Major objectives of the analysis were to identify plausible failure mechanisms and to develop a method for determining which failure mode would occur first in different light water reactor designs and accident conditions. Failure mechanisms, such as tube ejection, tube rupture, global vessel failure, and localized vessel creep rupture, were studied. Newly developed models and existing models were applied to predict which failure mechanism would occur first in various severe accident scenarios. So that a broader range of conditions could be considered simultaneously, calculations relied heavily on models with closed-form or simplified numerical solution techniques. Finite element techniques-were employed for analytical model verification and examining more detailed phenomena. High-temperature creep and tensile data were obtained for predicting vessel and penetration structural response.

  15. Acute renal failure due to falciparum malaria.

    PubMed

    Habte, B

    1990-01-01

    Seventy-two patients with severe falciparum malaria are described. Twenty-four (33.3%) were complicated by acute renal failure. Comparing patients with renal failure and those without, statistically significant differences occurred regarding presence of cerebral malaria (83% vs 46%), jaundice (92% vs 33%), and death (54% vs 17%). A significantly higher number of patients with renal failure were nonimmune visitors to malaria endemic regions. Renal failure was oliguric in 45% of cases. Dialysis was indicated in 38%, 29% died in early renal failure, and 33% recovered spontaneously. It is concluded that falciparum malaria is frequently complicated by cerebral malaria and renal failure. As nonimmune individuals are prone to develop serious complications, malaria prophylaxis and vigorous treatment of cases is mandatory. PMID:2236718

  16. Renovascular heart failure: heart failure in patients with atherosclerotic renal artery disease.

    PubMed

    Kawarada, Osami; Yasuda, Satoshi; Noguchi, Teruo; Anzai, Toshihisa; Ogawa, Hisao

    2016-07-01

    Atherosclerotic renal artery disease presents with a broad spectrum of clinical features, including heart failure as well as hypertension, and renal failure. Although recent randomized controlled trials failed to demonstrate renal artery stenting can reduce blood pressure or the number of cardiovascular or renal events more so than medical therapy, increasing attention has been paid to flash pulmonary edema and congestive heart failure associated with atherosclerotic renal artery disease. This clinical entity "renovascular heart failure" is diagnosed retrospectively. Given the increasing global burden of heart failure, this review highlights the background and catheter-based therapeutic aspects for renovascular heart failure.

  17. Muscle reflex in heart failure: the role of exercise training

    PubMed Central

    Wang, Han-Jun; Zucker, Irving H.; Wang, Wei

    2012-01-01

    Exercise evokes sympathetic activation and increases blood pressure and heart rate (HR). Two neural mechanisms that cause the exercise-induced increase in sympathetic discharge are central command and the exercise pressor reflex (EPR). The former suggests that a volitional signal emanating from central motor areas leads to increased sympathetic activation during exercise. The latter is a reflex originating in skeletal muscle which contributes significantly to the regulation of the cardiovascular and respiratory systems during exercise. The afferent arm of this reflex is composed of metabolically sensitive (predominantly group IV, C-fibers) and mechanically sensitive (predominately group III, A-delta fibers) afferent fibers. Activation of these receptors and their associated afferent fibers reflexively adjusts sympathetic and parasympathetic nerve activity during exercise. In heart failure, the sympathetic activation during exercise is exaggerated, which potentially increases cardiovascular risk and contributes to exercise intolerance during physical activity in chronic heart failure (CHF) patients. A therapeutic strategy for preventing or slowing the progression of the exaggerated EPR may be of benefit in CHF patients. Long-term exercise training (ExT), as a non-pharmacological treatment for CHF increases exercise capacity, reduces sympatho-excitation and improves cardiovascular function in CHF animals and patients. In this review, we will discuss the effects of ExT and the mechanisms that contribute to the exaggerated EPR in the CHF state. PMID:23060821

  18. Failure mode analysis to predict product reliability.

    NASA Technical Reports Server (NTRS)

    Zemanick, P. P.

    1972-01-01

    The failure mode analysis (FMA) is described as a design tool to predict and improve product reliability. The objectives of the failure mode analysis are presented as they influence component design, configuration selection, the product test program, the quality assurance plan, and engineering analysis priorities. The detailed mechanics of performing a failure mode analysis are discussed, including one suggested format. Some practical difficulties of implementation are indicated, drawn from experience with preparing FMAs on the nuclear rocket engine program.

  19. Failure of Non-Circular Composite Cylinders

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.

    2004-01-01

    In this study, a progressive failure analysis is used to investigate leakage in internally pressurized non-circular composite cylinders. This type of approach accounts for the localized loss of stiffness when material failure occurs at some location in a structure by degrading the local material elastic properties by a certain factor. The manner in which this degradation of material properties takes place depends on the failure modes, which are determined by the application of a failure criterion. The finite-element code STAGS, which has the capability to perform progressive failure analysis using different degradation schemes and failure criteria, is utilized to analyze laboratory scale, graphite-epoxy, elliptical cylinders with quasi-isotropic, circumferentially-stiff, and axially-stiff material orthotropies. The results are divided into two parts. The first part shows that leakage, which is assumed to develop if there is material failure in every layer at some axial and circumferential location within the cylinder, does not occur without failure of fibers. Moreover before fibers begin to fail, only matrix tensile failures, or matrix cracking, takes place, and at least one layer in all three cylinders studied remain uncracked, preventing the formation of a leakage path. That determination is corroborated by the use of different degradation schemes and various failure criteria. Among the degradation schemes investigated are the degradation of different engineering properties, the use of various degradation factors, the recursive or non-recursive degradation of the engineering properties, and the degradation of material properties using different computational approaches. The failure criteria used in the analysis include the noninteractive maximum stress criterion and the interactive Hashin and Tsai-Wu criteria. The second part of the results shows that leakage occurs due to a combination of matrix tensile and compressive, fiber tensile and compressive, and inplane

  20. Failure modes in surface micromachined microelectromechanical actuators

    SciTech Connect

    Miller, S.L.; Rodgers, M.S.; LaVigne, G.; Sniegowski, J.J.; Clews, P.; Tanner, D.M.; Peterson, K.A.

    1998-03-01

    In order for the rapidly emerging field of MicroElectroMechanical Systems (MEMS) to meet its extraordinary expectations regarding commercial impact, issues pertaining to how they fail must be understood. The authors identify failure modes common to a broad range of MEMS actuators, including adhesion (stiction) and friction induced failures caused by improper operational methods, mechanical instabilities, and electrical instabilities. Demonstrated methods to mitigate these failure modes include implementing optimized designs, model based operational methods, and chemical surface treatments.

  1. ASPH modeling of Material Damage and Failure

    SciTech Connect

    Owen, J M

    2010-04-30

    We describe our new methodology for Adaptive Smoothed Particle Hydrodynamics (ASPH) and its application to problems in modeling material failure. We find that ASPH is often crucial for properly modeling such experiments, since in most cases the strain placed on materials is non-isotropic (such as a stretching rod), and without the directional adaptability of ASPH numerical failure due to SPH nodes losing contact in the straining direction can compete with or exceed the physical process of failure.

  2. Energy efficiency, market failures, and government policy

    SciTech Connect

    Levine, M.D.; Koomey, J.G.; McMahon, J.E.; Sanstad, A.H.; Hirst, E.

    1994-03-01

    This paper presents a framework for evaluating engineering-economic evidence on the diffusion of energy efficiency improvements. Four examples are evaluated within this framework. The analysis provides evidence of market failures related to energy efficiency. Specific market failures that may impede the adoption of cost-effective energy efficiency are discussed. Two programs that have had a major impact in overcoming these market failures, utility DSM programs and appliance standards, are described.

  3. Strain limit criteria to predict failure

    SciTech Connect

    Flanders, H.E.

    1995-12-31

    In recent years extensive effort has been expended to qualify existing structures for conditions that are beyond the original design basis. Determination of the component failure load is useful for this type of evaluation. This paper presents criteria based upon strain limits to predict the load at failure. The failure modes addressed are excessive plastic deformations, localized plastic strains, and structural instability. The effects of analytical method sophistication, as built configurations, material properties degradation, and stress state are addressed by the criteria.

  4. Potentiel des images satellitaires multibandes a haute resolution spatiale pour la cartographie des componsants de l'eau en milieu cotier marin

    NASA Astrophysics Data System (ADS)

    Lavoie, Andre

    L'objectif principal que que nous poursuivons est de developper un modele de simulation du transfert radiatif eau-atmosphere adapte aux observations faites par le capteur Thematic Mapper (TM) de Landsat. Les informations que nous cherchons ont trait au milieu cotier marin et concernent les elements qui sont en suspension dans l'eau. Les images multibandes du capteur TM dans la partie visible du spectre, sont surtout visees par nos travaux. A la base de la simulation, nous utilisons un programme de simulation atmospherique, le code 6S, auquel nous greffons un modele de simulation du transfert radiatif dans la masse d'eau. Ce dernier estime le signal en fonction de 4 composants: l'eau, les pigments chlorophylliens (chlorophylle et phaeopigments), les matieres minerales et les substances organiques dissoutes. La concentration des differents composants sert de parametre d'entree pour definir le comportement optique de la masse d'eau. Le modele permet egalement de simuler une masse d'eau stratifiee si l'on connai t les concentrations des composants dans les differentes couches. Il inclut aussi la contribution du fond, selon sa nature et sa composition, ainsi que celle du miroitement du soleil et du ciel a la surface de l'eau. Les informations d'un echantillonnage de la masse d' eau synchronise avec le passage du satellite, a la baie des Chaleurs, d'une cartographie du couvert d'algues et d'un modele bathymetrique ont ete utilisees pour fixer les parametres de simulation par le modele. La comparaison montrent que le modele se comporte relativement bien surtout dans la bande TM2. Une erreur systematique de 2 valeurs numeriques en moyenne subsiste dans les trois bandes spectrales. Les resultats nous montrent que la visibilite du fond aux faibles profondeurs est un element tres important a considerer. Par ailleurs, l'analyse de sensibilite montre que les images TM sont plus sensibles aux concentrations en matieres minerales qu'aux pigments chlorophylliens et aux substances

  5. Sécurité au-delà des mythes et des croyances

    ScienceCinema

    None

    2016-07-12

    Présentation orale en français, support visuel en français et en anglais. La pire des failles de sécurité est l'impression de sécurité. Le décalage entre la compréhension que l’on a des technologies utilisées, et leurs potentiels réels, ainsi que l'impact potentiellement négatif qu'elles peuvent avoir sur nos vies, n'est pas toujours compris, ou pris en compte par la plupart d'entre-nous. On se contente de nos perceptions pour ne pas avoir à se confronter à la réalité... Alors qu'en est-il vraiment ? En matière de sécurité qui de l'humain ou des technologies a le contrôle ?

  6. Evaluation des connaissances des parents sur les bronchiolites aiguës

    PubMed Central

    Gueddari, Widad; Tazi, Abderrahmane; Ouardi, Amine; Nani, Samira; Zineddine, Abdelhadi

    2014-01-01

    Les infections respiratoires (IR) constituent la deuxième cause de mortalité infantile au Maroc, dû en partie à l'absence d'information et de sensibilisation. Le but de ce travail était d’évaluer les connaissances des parents sur la bronchiolite aiguë, infection respiratoire très fréquente. Nous avons réalisé une enquête basée sur un questionnaire, auprès de parents de nourrissons consultants pour toux, avec ou sans gêne respiratoire. 180 parents ont été inclus dans l’étude. Les parents pensaient que l'infection respiratoire était secondaire au climat froid (96%); seuls 4% ont évoqué une origine infectieuse. Aucun des parents ne savait que le lavage des mains était un moyen de prévention de la transmission. Les parents ont majoritairement répondu que la kinésithérapie respiratoire ne servait à rien (65%), et qu'elle était nocive (24.5%). Ce manque de connaissances fondamentales en matière d'IR et de bronchiolite en particulier, devrait inciter à entreprendre un programme de sensibilisation PMID:25328606

  7. Explanatory Models of Heart Failure Etiology

    PubMed Central

    Clark, Angela P.; McDougall, Graham J.; Joiner-Rogers, Glenda; Innerarity, Sheri; Delville, Carol; Meraviglia, Marty; Davila, Ashley

    2014-01-01

    Chronic health failure is a leading cause of hospital readmissions and is reaching epidemic proportions in the United States. Explanatory models of illness can provide insight about how people with heart failure perceive their etiology of heart failure. Six themes were found in this descriptive, qualitative study to explore the perceived origin of heart failure in 50 participants. Forty percent of the people were unaware of why they had the diagnosis. Misconceptions and misinformation were common, including confusion about whether the symptoms themselves caused the disease. PMID:22156813

  8. Focus on renal congestion in heart failure.

    PubMed

    Afsar, Baris; Ortiz, Alberto; Covic, Adrian; Solak, Yalcin; Goldsmith, David; Kanbay, Mehmet

    2016-02-01

    Hospitalizations due to heart failure are increasing steadily despite advances in medicine. Patients hospitalized for worsening heart failure have high mortality in hospital and within the months following discharge. Kidney dysfunction is associated with adverse outcomes in heart failure patients. Recent evidence suggests that both deterioration in kidney function and renal congestion are important prognostic factors in heart failure. Kidney congestion in heart failure results from low cardiac output (forward failure), tubuloglomerular feedback, increased intra-abdominal pressure or increased venous pressure. Regardless of the cause, renal congestion is associated with increased morbidity and mortality in heart failure. The impact on outcomes of renal decongestion strategies that do not compromise renal function should be explored in heart failure. These studies require novel diagnostic markers that identify early renal damage and renal congestion and allow monitoring of treatment responses in order to avoid severe worsening of renal function. In addition, there is an unmet need regarding evidence-based therapeutic management of renal congestion and worsening renal function. In the present review, we summarize the mechanisms, diagnosis, outcomes, prognostic markers and treatment options of renal congestion in heart failure.

  9. Failure of endodontic treatment: The usual suspects

    PubMed Central

    Tabassum, Sadia; Khan, Farhan Raza

    2016-01-01

    Inappropriate mechanical debridement, persistence of bacteria in the canals and apex, poor obturation quality, over and under extension of the root canal filling, and coronal leakage are some of the commonly attributable causes of failure. Despite the high success rate of endodontic treatment, failures do occur in a large number of cases and most of the times can be attributed to the already stated causes. With an ever increasing number of endodontic treatments being done each day, it has become imperative to avoid or minimize the most fundamental of reasons leading to endodontic failure. This paper reviews the most common causes of endodontic failure along with radiographic examples. PMID:27011754

  10. [Perioperative acute kidney injury and failure].

    PubMed

    Chhor, Vibol; Journois, Didier

    2014-04-01

    Perioperative period is very likely to lead to acute renal failure because of anesthesia (general or perimedullary) and/or surgery which can cause acute kidney injury. Characterization of acute renal failure is based on serum creatinine level which is imprecise during and following surgery. Studies are based on various definitions of acute renal failure with different thresholds which skewed their comparisons. The RIFLE classification (risk, injury, failure, loss, end stage kidney disease) allows clinicians to distinguish in a similar manner between different stages of acute kidney injury rather than using a unique definition of acute renal failure. Acute renal failure during the perioperative period can mainly be explained by iatrogenic, hemodynamic or surgical causes and can result in an increased morbi-mortality. Prevention of this complication requires hemodynamic optimization (venous return, cardiac output, vascular resistance), discontinuation of nephrotoxic drugs but also knowledge of the different steps of the surgery to avoid further degradation of renal perfusion. Diuretics do not prevent acute renal failure and may even push it forward especially during the perioperative period when venous retourn is already reduced. Edema or weight gain following surgery are not correlated with the vascular compartment volume, much less with renal perfusion. Treatment of perioperative acute renal failure is similar to other acute renal failure. Renal replacement therapy must be mastered to prevent any additional risk of hemodynamic instability or hydro-electrolytic imbalance.

  11. Modelling the failure behaviour of wind turbines

    NASA Astrophysics Data System (ADS)

    Faulstich, S.; Berkhout, V.; Mayer, J.; Siebenlist, D.

    2016-09-01

    Modelling the failure behaviour of wind turbines is an essential part of offshore wind farm simulation software as it leads to optimized decision making when specifying the necessary resources for the operation and maintenance of wind farms. In order to optimize O&M strategies, a thorough understanding of a wind turbine's failure behaviour is vital and is therefore being developed at Fraunhofer IWES. Within this article, first the failure models of existing offshore O&M tools are presented to show the state of the art and strengths and weaknesses of the respective models are briefly discussed. Then a conceptual framework for modelling different failure mechanisms of wind turbines is being presented. This framework takes into account the different wind turbine subsystems and structures as well as the failure modes of a component by applying several influencing factors representing wear and break failure mechanisms. A failure function is being set up for the rotor blade as exemplary component and simulation results have been compared to a constant failure rate and to empirical wind turbine fleet data as a reference. The comparison and the breakdown of specific failure categories demonstrate the overall plausibility of the model.

  12. Failure Waves in Cylindrical Glass Bars

    NASA Astrophysics Data System (ADS)

    Cazamias, James U.; Bless, Stephan J.; Marder, Michael P.

    1997-07-01

    Failure waves, a propagating front separating virgin and comminuted material, have been receiving a fair amount of attention the last couple of years. While most scientists have been looking at failure waves in plate impact geometries, we have conducted a series of experiments on Pyrex bars. In this paper, we present two types of photographic data from a series of tests. A streak camera was used to determine velocities of the failure front as a function of impact stress. A polaroid camera and a flash lamp provide detailed pictures of the actual event. Attempts were made to observe failure waves in amorphous quartz and acrylic.

  13. Jesuits' Contribution to Meteorology.

    NASA Astrophysics Data System (ADS)

    Udías, Agustín

    1996-10-01

    Starting in the middle of the nineteenth century, as part of their scientific tradition, Jesuits founded a considerable number of meteorological observatories throughout the world. In many countries, Jesuits established and maintained the first meteorological stations during the period from 1860 to 1950. The Jesuits' most important contribution to atmospheric science was their pioneer work related to the study and forecast of tropical hurricanes. That research was carried out at observatories of Belén (Cuba), Manila (Philippines), and Zikawei (China). B. Viñes, M. Decheyrens, J. Aigué, and C.E. Deppermann stood out in this movement.

  14. Examining suicide: imaging's contributions.

    PubMed

    Church, Elizabeth J

    2015-01-01

    For many people, the death of hope leads inexorably to the conclusion that the only viable solution, the only way to put an end to unendurable pain, is suicide. What leads a person to commit this final, desperate act, and how might we predict, intervene, and prevent suicide? Health care workers, including radiologic technologists, can play an important role in detecting warning signs in patients and in better understanding what factors may lead to suicide. Although certain forms of suicide such as suicide bombings and assisted suicide are beyond its scope, this article explores medical imaging's contributions to the study of this phenomenon.

  15. Genetic and environmental contributions.

    PubMed

    Jensen, M D

    2000-03-01

    There is a remarkable variability in insulin action in humans. Depending upon the definition of the insulin resistance syndrome, different inheritability/environmental influences on insulin action are reported. The environmental contributions to insulin resistance appear to account for approximately 50% of this syndrome. Obese and sedentary insulin-resistant individuals can see dramatic improvement in insulin sensitivity with weight reduction and fitness training. The degree to which obesity is determined by genetic influences will have a substantial impact on insulin resistance in the Western populations. Familial components also appear to account for approximately 50% of the variation and insulin action (as commonly defined by glucose metabolic effects).

  16. [Outpatient rehabilitation after myocardial infarction or for heart failure].

    PubMed

    Fischer, H M; Charrier, A; Dörr, R; Spitzer, S G

    2012-02-01

    Reducing cardiac mortality and improving quality of life are the main objectives of cardiac rehabilitation. In recent years, outpatient rehabilitation within easy patient reach has achieved the same status as inpatient rehabilitation. Outpatient rehabilitation permits close involvement of the patient's family and social environment, thus easing reintegration into everyday life. However, the health care system is not yet utilizing outpatient rehabilitation to its full potential. This contribution illustrates the principles of rehabilitation following myocardial infarction or for heart failure in an outpatient setting, as well as its potential and future development.

  17. Potential applications of pharmacogenomics to heart failure therapies.

    PubMed

    Parikh, Kishan S; Ahmad, Tariq; Fiuzat, Mona

    2014-10-01

    Pharmacogenomics explores one drug's varying effects on different patient genotypes. A better understanding of genomic variation's contribution to drug response can impact 4 arenas in heart failure (HF): (1) identification of patients most likely to receive benefit from therapy, (2) risk stratify patients for risk of adverse events, (3) optimize dosing of drugs, and (4) steer future clinical trial design and drug development. In this review, the authors explore the potential applications of pharmacogenomics in patients with HF in the context of these categories.

  18. Corrosion and failure processes in high-level waste tanks

    SciTech Connect

    Mahidhara, R.K.; Elleman, T.S.; Murty, K.L.

    1992-11-01

    A large amount of radioactive waste has been stored safely at the Savannah River and Hanford sites over the past 46 years. The aim of this report is to review the experimental corrosion studies at Savannah River and Hanford with the intention of identifying the types and rates of corrosion encountered and indicate how these data contribute to tank failure predictions. The compositions of the High-Level Wastes, mild steels used in the construction of the waste tanks and degradation-modes particularly stress corrosion cracking and pitting are discussed. Current concerns at the Hanford Site are highlighted.

  19. DES the year in review: controversies.

    PubMed

    Garg, S; Bourantas, C; Serruys, P W

    2013-04-01

    Drug-eluting stents (DES) have transformed interventional cardiology over the past decade. Whilst their efficacy has rarely been called into question, there have been concerns over the safety of the early devices, which has prompted the development of new coronary stents. Many of these new devices have entered clinical practice, however questions remain as to whether they offer the improvements in clinical outcomes that were originally anticipated. In addition, there is a debate whether the reported high efficacy of these devices enables percutaneous coronary intervention (PCI) to be performed in patient and lesion sub-groups previous entirely the domain of the cardiac surgeon. This review paper addresses these outstanding questions. PMID:23492595

  20. Formation et Evolution des Quasars et Contraintes cosmologiques

    NASA Astrophysics Data System (ADS)

    Hatziminaoglou, Evanthia

    2000-06-01

    Cette thèse porte sur l'étude de l'évolution des quasars. Elle en aborde certains aspects théoriques et observationnels, ainsi que la construction des grands échantillons de quasars dans le but à long terme de combiner le tout dans un test cosmologique géométrique pour déterminer les valeurs des paramètres cosmologiques Omega et Lambda. Les paramètres cosmologiques Omegaspan>et Lambdaspan>décrivent la géométrie globale de l'Univers. En faisant des hypothèses raisonnables sur la distribution spatiale et l'évolution des objets astrophysiques (galaxies, amas des galaxies, quasars), on peut déterminer les valeurs de ces paramètres qui sont cohérentes avec ces hypothèses. Les tests cosmologiques traditionnels ont besoin de ''chandelles standards'', objets dont les propriétés intrinsèques sont indépendantes des distances. De tels objets sont probablement fictifs. Néanmoins, certains de ces tests cosmologiques peuvent être adaptés si l'évolution individuelle, ou au moins l'évolution statistique d'une population d'objets est connue. La question de la nature de l'évolution des quasars a très vite été posée et des réponses ''phénoménologiques'' ont d'abord été données. Ces réponses ne faisaient que donner une forme mathématique à l'évolution mais n'expliquaient rien de la physique duphénomène. Les premières tentatives de construction d'un modèle physique, liées au processus d'accrétion sur un trou noir et à la théorie de la formation de l'Univers ont commencé à la fin des années 80. Depuis, des dizaines de modèles tentent d'expliquer les observations, qui sont les résultats de l'étude d'objets de plus en plus nombreux. Au cours de cette thèse, le test V/Vmax a été appliqué sur l'échantillon du Large Bright Quasar Survey en montrant 1) que l'échantillon était biaisé à cause des critères de sélection et 2) que la (simple) loi de Pure Evolution en Luminosité n'était pas une bonne approximation à tout